This document describes a study that identified and characterized two actinomycete bacterial strains with
antagonistic activity against Streptomyces scabies, the pathogen that causes potato scab disease. The two strains
were isolated from soil samples. Molecular characterization using 16S rDNA gene sequencing identified the first
strain as Streptomyces avermitilis and the second strain as Actinomyces odontolyticus. Both strains showed high
levels of antibiosis against S. scabies in in vitro and in vivo assays, effectively controlling potato scab disease
symptoms on potato varieties Cara and Diamond.
Avs significant achievements and present status of trichoderma spp. inAMOL SHITOLE
This document summarizes a seminar presentation on the significant achievements and present status of Trichoderma spp. in biocontrol of plant diseases.
The summary includes:
1) Trichoderma spp. are filamentous fungi commonly used as biocontrol agents due to their ability to control plant pathogens through competition, mycoparasitism, and induced resistance.
2) Mutation induction using physical and chemical mutagens has been used to improve the biocontrol potential of Trichoderma spp. by impacting their morphological, biochemical, and mycoparasitic properties.
3) Studies presented show mutants exhibiting increased growth, sporulation, antibiotic production, and tolerance to stress
— The microbiological content of Lettuce (a vegetable), commonly vended in the Benin metropolis of Edo state were evaluated. Five vending locations were chosen for the study. Whole and soft rot samples were purchased and analysed for microbiological composition. Results showed high counts in soft rot samples in lettuce. Nutrient agar plated lettuce samples had bacterial counts in the range of 2.0x 103 to 4.7x10 7. Pseudomonas species was the dominant species found in lettuce samples. Bacillus species was isolated from one location in the lettuce samples. Mac Conkey agar plated lettuce plated had bacterial counts in the range of 2.3 x 10 3 to 5.7x 10 7. Enterobacter species, E. coli, and Klebsiella species were the dominant species isolated. Though, Proteus species was isolated from lettuce samples obtained from location five only. The study observes that consuming soft rot samples could pose a risk of introducing pathogens to the consumer due to their high microbial counts and could be detrimental to the health of the consumer.
Gut microflora and their role in susceptibility of lepidopteran pests to baci...Prema Latha
The document discusses the role of gut microflora in the susceptibility of lepidopteran pests to Bacillus thuringiensis. It provides background on the diversity of gut microbes in different insect orders. Case studies show that certain gut bacteria can promote the insecticidal activity of Bt by cleaving Bt crystal proteins or having synergistic effects with Bt. The toxicity of Bt towards cotton bollworm was reduced when the insects were pre-treated with antibiotics, indicating that gut microflora influence Bt susceptibility.
Bioactivity screening of soil bacteria against human pathogenspharmaindexing
1) Soil bacteria were isolated from three soil samples and screened for bioactivity against human pathogens.
2) A total of 36 soil bacteria isolates were obtained, of which 14 showed antibacterial activity against pathogens like S. aureus, S. feacalis, E. coli, K. aerogenes, P. vulgaris, P. aureginosa and S. typhi in preliminary screening.
3) The 3 most active isolates were grown in culture media to produce bioactive metabolites, which were extracted and found to have prominent antimicrobial effects against the test pathogens.
This document provides prefaces to the second edition and English edition of a book titled "Pictorial Atlas of Soil and Seed Fungi". The book contains photographs and descriptions of 308 fungal species isolated from soil and seeds. It has been revised to include additional fungal species and updated classification information. The prefaces discuss the importance of studying soil fungi and their role in ecosystems, as well as the lack of resources on the morphology of soil and seed fungi. The book aims to increase knowledge and interest in these often overlooked fungi.
This study evaluated methods for eliminating potato viruses Potato leafroll virus (PLRV) and Potato virus X (PVX) from infected potato cultivars. Thermotherapy at 38°C for 3 weeks eliminated PLRV from 80% of tubers but only 33.3% of PVX. Combining thermotherapy with meristem tip culture achieved 93.1% elimination of PLRV and 76% of PVX. Virus-free plantlets were grown in a greenhouse with different soil mixtures. Vermiculite and sand produced the largest minituber diameter for both cultivars. This research developed effective methods for producing virus-free potato plantlets and minitubers.
Biological Control Mechanism- by KanishKanish Sarker
Fluorescent pseudomonads can be used as biological control agents against plant pathogens through several mechanisms. They produce siderophores like pyoverdin and pyochelin that compete with pathogens for iron. Secondary metabolites like 2,4-diacetylphloroglucinol (DAPG), pyrrolnitrin, and phenazines also inhibit pathogens. Some fluorescent pseudomonads induce systemic resistance in plants via the jasmonic acid/ethylene pathway. Understanding the regulation of traits involved in biological control can help improve the use of fluorescent pseudomonads as sustainable alternatives to chemicals for controlling plant diseases.
Effects of six selected antibiotics on plant growth and soil microbial and en...Junior Dou
This study examined the effects of six antibiotics (chlortetracycline, tetracycline, tylosin, sulfamethoxazole, sulfamethazine, and trimethoprim) on plant growth, soil microbial activity, and soil enzyme activity. Seed germination tests and plant growth tests in soil were conducted on three plant species (rice, cucumber, and sweet oat) to assess phytotoxicity. Soil respiration and phosphatase activity were also measured to evaluate the impact on soil microbial activity. The results showed varying effects between antibiotics and plant species. Rice was most sensitive to sulfamethoxazole. All antibiotics inhibited soil phosphatase activity. Sulfonamides and trimethoprim significantly
Avs significant achievements and present status of trichoderma spp. inAMOL SHITOLE
This document summarizes a seminar presentation on the significant achievements and present status of Trichoderma spp. in biocontrol of plant diseases.
The summary includes:
1) Trichoderma spp. are filamentous fungi commonly used as biocontrol agents due to their ability to control plant pathogens through competition, mycoparasitism, and induced resistance.
2) Mutation induction using physical and chemical mutagens has been used to improve the biocontrol potential of Trichoderma spp. by impacting their morphological, biochemical, and mycoparasitic properties.
3) Studies presented show mutants exhibiting increased growth, sporulation, antibiotic production, and tolerance to stress
— The microbiological content of Lettuce (a vegetable), commonly vended in the Benin metropolis of Edo state were evaluated. Five vending locations were chosen for the study. Whole and soft rot samples were purchased and analysed for microbiological composition. Results showed high counts in soft rot samples in lettuce. Nutrient agar plated lettuce samples had bacterial counts in the range of 2.0x 103 to 4.7x10 7. Pseudomonas species was the dominant species found in lettuce samples. Bacillus species was isolated from one location in the lettuce samples. Mac Conkey agar plated lettuce plated had bacterial counts in the range of 2.3 x 10 3 to 5.7x 10 7. Enterobacter species, E. coli, and Klebsiella species were the dominant species isolated. Though, Proteus species was isolated from lettuce samples obtained from location five only. The study observes that consuming soft rot samples could pose a risk of introducing pathogens to the consumer due to their high microbial counts and could be detrimental to the health of the consumer.
Gut microflora and their role in susceptibility of lepidopteran pests to baci...Prema Latha
The document discusses the role of gut microflora in the susceptibility of lepidopteran pests to Bacillus thuringiensis. It provides background on the diversity of gut microbes in different insect orders. Case studies show that certain gut bacteria can promote the insecticidal activity of Bt by cleaving Bt crystal proteins or having synergistic effects with Bt. The toxicity of Bt towards cotton bollworm was reduced when the insects were pre-treated with antibiotics, indicating that gut microflora influence Bt susceptibility.
Bioactivity screening of soil bacteria against human pathogenspharmaindexing
1) Soil bacteria were isolated from three soil samples and screened for bioactivity against human pathogens.
2) A total of 36 soil bacteria isolates were obtained, of which 14 showed antibacterial activity against pathogens like S. aureus, S. feacalis, E. coli, K. aerogenes, P. vulgaris, P. aureginosa and S. typhi in preliminary screening.
3) The 3 most active isolates were grown in culture media to produce bioactive metabolites, which were extracted and found to have prominent antimicrobial effects against the test pathogens.
This document provides prefaces to the second edition and English edition of a book titled "Pictorial Atlas of Soil and Seed Fungi". The book contains photographs and descriptions of 308 fungal species isolated from soil and seeds. It has been revised to include additional fungal species and updated classification information. The prefaces discuss the importance of studying soil fungi and their role in ecosystems, as well as the lack of resources on the morphology of soil and seed fungi. The book aims to increase knowledge and interest in these often overlooked fungi.
This study evaluated methods for eliminating potato viruses Potato leafroll virus (PLRV) and Potato virus X (PVX) from infected potato cultivars. Thermotherapy at 38°C for 3 weeks eliminated PLRV from 80% of tubers but only 33.3% of PVX. Combining thermotherapy with meristem tip culture achieved 93.1% elimination of PLRV and 76% of PVX. Virus-free plantlets were grown in a greenhouse with different soil mixtures. Vermiculite and sand produced the largest minituber diameter for both cultivars. This research developed effective methods for producing virus-free potato plantlets and minitubers.
Biological Control Mechanism- by KanishKanish Sarker
Fluorescent pseudomonads can be used as biological control agents against plant pathogens through several mechanisms. They produce siderophores like pyoverdin and pyochelin that compete with pathogens for iron. Secondary metabolites like 2,4-diacetylphloroglucinol (DAPG), pyrrolnitrin, and phenazines also inhibit pathogens. Some fluorescent pseudomonads induce systemic resistance in plants via the jasmonic acid/ethylene pathway. Understanding the regulation of traits involved in biological control can help improve the use of fluorescent pseudomonads as sustainable alternatives to chemicals for controlling plant diseases.
Effects of six selected antibiotics on plant growth and soil microbial and en...Junior Dou
This study examined the effects of six antibiotics (chlortetracycline, tetracycline, tylosin, sulfamethoxazole, sulfamethazine, and trimethoprim) on plant growth, soil microbial activity, and soil enzyme activity. Seed germination tests and plant growth tests in soil were conducted on three plant species (rice, cucumber, and sweet oat) to assess phytotoxicity. Soil respiration and phosphatase activity were also measured to evaluate the impact on soil microbial activity. The results showed varying effects between antibiotics and plant species. Rice was most sensitive to sulfamethoxazole. All antibiotics inhibited soil phosphatase activity. Sulfonamides and trimethoprim significantly
Identification of Ralstonia Solanacearum in Kyrgyzstan’s Potato Fields and th...Agriculture Journal IJOEAR
Abstract— In this study, we have used well-known, efficient methods and bioassay for systematic screening of R. solanacearum for identification of its phenotype and biochemical profile, as well as for pathogenicity and virulence. As a result, an aggressive race — Biovar 3 — was most isolated from the potato fields of the Issyk-Kul region, especially in fields where the Picasso variety was grown. The isolated indigenous strains of Streptomyces diastatochromogenesstrain sk-6 and Streptomyces bambergiensis strain k1-3 has the potential to be used as a biocontrol agent for the management of the bacterial wilt of potatoes, as indicated by the reduced percentage wilt incidence. Root zone and soil application of Streptomyces diastatochromogenesstrain sk-6 and Streptomyces bambergiensis strain k1-3 at a dose of 108 cell/ml significantly reduced disease incidence and increased the growth of potato plants. The disease’s progress was reduced by 60% and 56% in plants inoculated with Streptomyces diastatochromogenesstrain sk-6 and Streptomyces bambergiensis strain k1-3, respectively.
Fungi-Nematode Interaction: Diversity, Ecology and Bio-control Prospects in A...UASR, UASD
Nematodes in the genera Aphelenchus, Aphelenchoides, Ditylenchus and Tylenchus are among the most common fungivorous nematodes
Fungivorous nematodes feed on a diversity of soil fungi, including saprophytic, plant-pathogenic and plant-beneficial (such as mycorrhizal) fungi and are known as polyphagous nematodes
Identification of Race/strain of Phytopathogenic Fungi through Conventional A...Sarda Konjengbam
Detection and identification of fungi has relied on a combination of microscopy and culture based techniques. Conventional methods often rely on identification of disease symptoms, isolation and culturing of environmental organisms, and laboratory identification by morphology and biochemical tests. These methods, although the cornerstone of fungal diagnostics, can lead to problems in identification, resulting in incorrect interpretation, diagnosis and ultimately treatment. The methods rely on experienced, skilled laboratory staff, the ability of the organism to be cultured, are time consuming, non quantitative, prone to contamination and error and often delay management (Atkins and Clark, 2004). During the last decades, the advent of molecular biology promised to offer radical alternatives in the detection and enumeration of fungal pathogens. Molecular technology increases understanding of the biology and population structures of plant pathogens, provides quick and accurate answers to epidemiological questions about plant diseases, and supports disease management decisions. New, rapid screening methods are being developed and increasingly used in all aspects of fungal diagnostics.
4068 isolation, identification and characterization of entomopathogenicSheena Prem
Control of white grub using entomopathogenic nematode (Heterorhabdtidae and steinernematidae )and entomopathogenic fungi Isolation of Symbiontic bacteria of antomopathogenic nematode .
Study of antagonistic capability of trichoderma harzianum isolates against so...AL-kitab university -IRAQ
This study evaluated the antagonistic potential of two isolates of Trichoderma harzianum against seven soil-borne pathogenic fungi. In dual culture tests, T. harzianum isolate T2 showed the highest inhibitory effect against the pathogens, reducing their mycelial growth by 45.99% on average. Alternaria sp. was most inhibited by T2 at 51.18%. Volatile metabolites from T2 were also effective at inhibiting pathogen growth. Non-volatile metabolites collected from T2 cultures at different time periods and concentrations inhibited pathogen mycelial growth, with the highest (100%) concentration having the greatest effect. Microscopic analysis revealed T2 interacting with and inhibiting the pathogens through mechanisms like coiling around their
Laboratory manual for fusarium research 3rd edition Lester BurgessMarcos Buitrago
Authors of this laboratory manual are Lester W. Burgess, Brett A. Summerell, Suzanne Bullock, Kathryn P. Gott and David Backhouse.
Fusarium Research Laboratory
Department of Crop Sciences
University of Sydney
August, 1994
This study evaluated endophytic bacteria from Pinus taeda L. as potential biocontrol agents of Fusarium circinatum, the causal agent of pitch canker disease affecting pine seedlings. Five bacterial strains - four Bacillus subtilis and one Burkholderia sp. isolated from healthy pine tissue - were tested against F. circinatum in dual culture experiments. All bacteria inhibited the fungal pathogen, arresting mycelial growth within 1 cm. Thermostable metabolites from the bacterial cultures also significantly reduced fungal growth over 50% when added to media. These endophytic bacteria adapted to pine tissues showed potential as biocontrol agents to control the pitch canker fungus in nurseries and prevent disease spread.
Isolation and Identification of Fungi from fast food restaurants in Langa BazarIJEAB
A total of (218) samples from Eleven different foods were processed between October 2016 and February 2017 which include (Tomato, Chicken meat, red meat, falafel, potato, bread, eggplant, cabbage, celery, cucumber and onion). Samples were collected from 4 different fast food restaurants inoculated on Potato dextrose agar and Sabouraud Dextrose Agar. Isolated fungus identified morphologically and microscopically in accordance with standard procedures. Results showed that six fungal genera were associated with the selected fast food restaurants. The isolated fungal genera were Aspergillus sp., Alternaria sp., Mucor sp., Rhizopus sp., Saccharomyces sp., Brettanomyces sp. The number of total colonies in October were 236 and in February were 119 and the number of colonies were higher when cultured on Potato dextrose agar than Sabouraud Dextrose Agar. There was variation in the pattern of occurrence of the fungus in fast foods Aspergillus sp. appears to be the most pathogenic fungi that present in the food samples.
Evaluation of four plants compost teas against fungi responsible for Corn dam...IJEABJ
Corn (Zea mays L.) is one of the most important cereals in Côte d'Ivoire. However, Corn seeds and seedlings are susceptible to infection by a number of soilborne fungi which caused seeds decay before or after germination. The objective of this study is to evaluate the suppressive effect of Four plants compost teas (Chromolaena odorata, Ricinus communis, Nicotiana tabacum, Azadiracta indica) on Corn damping off. In vitro assays showed a most suppressive effect of C. odorata and R. communis compost teas on mycelial growth of pathogenic fungi. Results of in vivo trials showed significant reduction of Corn seedlings diseases incidence and high seed germination percent after treatment with C. odorata, R. communis and A. indica compost teas. No efficiency effect was noted with N. tabacum compost tea. This study demonstrated the usefulness of compost tea as an efficient biological tool for the control of fungi responsible of corn damping-off.
CHITINASE AS THE MOST IMPORTANT SECONDARY METABOLITES OF STREPTOMYCES BACTERISIJSIT Editor
This document summarizes a study on chitinase produced by Streptomyces bacteria. 310 Streptomyces isolates were obtained from soil samples collected across East Azerbaijan, Iran. DNA was extracted from the isolates and screened using PCR for a gene encoding family 19 chitinase, which shows significant antifungal activity. One isolate with strong antifungal effects was identified as S. griseous based on 16S rDNA sequencing and presence of the chitinase gene. The results suggest certain Streptomyces isolates have potential as biological control agents against fungal plant pathogens due to production of antifungal family 19 chitinase.
This document discusses antibiotic resistance genes found in natural environments. It begins by reviewing the early discoveries of antibiotic resistance in pathogens. It then discusses how antibiotic resistance genes are often found in environmental bacteria and can spread between species through horizontal gene transfer, especially on mobile genetic elements like plasmids. The overuse of antibiotics in agriculture, aquaculture and livestock has contributed to the increased presence of these genes in natural ecosystems. Understanding the distribution and transfer of antibiotic resistance genes in nature is important for evaluating antibiotic usage and policies.
Effect of plant growth promoting rhizobacterial (PGPR) inoculation on growth ...IJEAB
This document summarizes a study that evaluated the effects of inoculating tomato plants with three plant growth-promoting rhizobacteria (PGPR) strains. The study found that all three strains (B. cereus 2027-2, P. agglomerans 2066-7, and S. proteamaculans 2025-1) significantly increased various growth parameters of the tomato plants compared to non-inoculated controls, including aerial plant length, root length, stem diameter, chlorophyll content, and yield. The three strains were selected for further characterization of their plant growth promotion mechanisms, which found that they exhibited various combinations of abilities to solubilize phosphate, fix nitrogen, and produce ammonia, ind
Isolation and Characterization of Bacteria from Tropical SoilsNicole Rivera
This document describes a study that aimed to isolate bacteria from tropical soils in Puerto Rico that have the potential to produce antibiotics. Soil samples were collected and bacteria were isolated through serial dilution and culturing. Four isolated bacteria were purified and characterized through gram staining, testing for antibiotic production against E. coli and M. luteus, PCR amplification with 16S rRNA primers, and DNA sequencing. Two of the bacteria showed potential as antibiotic producers against M. luteus. The isolation and characterization of soil bacteria with antibiotic properties could help address the growing problem of antibiotic resistance.
This study investigated the presence of the FimH adhesin gene and biofilm formation among 24 Enterobacter isolates recovered from urine samples of cystitis patients. PCR results revealed that 18 of the 24 isolates (75%) were positive for the FimH gene. Phenotypic assays showed that 17 of the 24 isolates (70.8%) were biofilm formers. There was a significant positive correlation between biofilm formation and the presence of the FimH gene, with the gene present in 16 of the 17 biofilm-forming isolates (94.1%). The results indicate the importance of the FimH adhesin in biofilm establishment and pathogenesis of cystitis infections.
The document provides an overview of different types of entomopathogenic microbes (viruses, bacteria, fungi, nematodes, protozoa) used for insect management. It discusses the history, mode of action, symptoms caused, and examples of specific microbes used to control various insect pests for different crops. These include Bacillus thuringiensis for lepidopteran larvae, Beauveria bassiana for sucking pests, Metarhizium anisopliae for beet armyworm and rhinoceros beetle, Steinernema carpocapsea for soil-dwelling insects, and Nosema locustae for grasshoppers. The advantages of using entomopathogenic
The document discusses the effects of various bioagents on the growth of Coleus forskohlii. Key findings include:
1) Inoculation with Trichoderma viride, Pseudomonas fluorescens, and neem cake improved growth characteristics like plant height and root weight of Coleus cuttings.
2) In field conditions, inoculation with Glomus fasciculatum and Pseudomonas fluorescens led to higher yields, nutrient uptake, and forskohlin content compared to the uninoculated control.
3) Inoculation with arbuscular mycorrhizal fungi like Glomus bagyaragii and Scutellosp
Distribution of fungi, bacteria and actinomycetes in relation to cropping pat...Dr. siddhant
Eight soil samples closely situated cultivated field with varying cropping patterns have been assayed for fungi, bacteria, actinomycetes. The microbial population in different plots differed to a considerable extent. Plot with thick coverege and short term cropping pattern gave higher fungal counts. The availability of substrates for microbial growth seems to be an important factor in governing the soil microbial population. A marginal difference in moisture content and PH plays a negligible role in the determination of soil microflora.
This document discusses the challenges of classifying protists, which are eukaryotic organisms that are not plants, animals, or fungi. Protists exhibit a wide variety in their characteristics such as being photosynthetic or motile, unicellular or multicellular, and living in various habitats. They are difficult to classify because some protists share similarities with organisms from other kingdoms. While classification of protists continues to evolve, they are believed to have been the first eukaryotes and some protist ancestors gave rise to plants, animals and fungi based on their evolutionary relationships.
Prokaryotes are unicellular organisms that are classified as bacteria or archaea. They vary greatly in size, shape, movement, nutrition, and metabolism. Prokaryotes play important roles in the living world as decomposers, producers, and nitrogen fixers, recycling nutrients and producing food and biomass that supports food chains. They are ecologically important due to their diversity and roles in ecosystems.
Identification of Ralstonia Solanacearum in Kyrgyzstan’s Potato Fields and th...Agriculture Journal IJOEAR
Abstract— In this study, we have used well-known, efficient methods and bioassay for systematic screening of R. solanacearum for identification of its phenotype and biochemical profile, as well as for pathogenicity and virulence. As a result, an aggressive race — Biovar 3 — was most isolated from the potato fields of the Issyk-Kul region, especially in fields where the Picasso variety was grown. The isolated indigenous strains of Streptomyces diastatochromogenesstrain sk-6 and Streptomyces bambergiensis strain k1-3 has the potential to be used as a biocontrol agent for the management of the bacterial wilt of potatoes, as indicated by the reduced percentage wilt incidence. Root zone and soil application of Streptomyces diastatochromogenesstrain sk-6 and Streptomyces bambergiensis strain k1-3 at a dose of 108 cell/ml significantly reduced disease incidence and increased the growth of potato plants. The disease’s progress was reduced by 60% and 56% in plants inoculated with Streptomyces diastatochromogenesstrain sk-6 and Streptomyces bambergiensis strain k1-3, respectively.
Fungi-Nematode Interaction: Diversity, Ecology and Bio-control Prospects in A...UASR, UASD
Nematodes in the genera Aphelenchus, Aphelenchoides, Ditylenchus and Tylenchus are among the most common fungivorous nematodes
Fungivorous nematodes feed on a diversity of soil fungi, including saprophytic, plant-pathogenic and plant-beneficial (such as mycorrhizal) fungi and are known as polyphagous nematodes
Identification of Race/strain of Phytopathogenic Fungi through Conventional A...Sarda Konjengbam
Detection and identification of fungi has relied on a combination of microscopy and culture based techniques. Conventional methods often rely on identification of disease symptoms, isolation and culturing of environmental organisms, and laboratory identification by morphology and biochemical tests. These methods, although the cornerstone of fungal diagnostics, can lead to problems in identification, resulting in incorrect interpretation, diagnosis and ultimately treatment. The methods rely on experienced, skilled laboratory staff, the ability of the organism to be cultured, are time consuming, non quantitative, prone to contamination and error and often delay management (Atkins and Clark, 2004). During the last decades, the advent of molecular biology promised to offer radical alternatives in the detection and enumeration of fungal pathogens. Molecular technology increases understanding of the biology and population structures of plant pathogens, provides quick and accurate answers to epidemiological questions about plant diseases, and supports disease management decisions. New, rapid screening methods are being developed and increasingly used in all aspects of fungal diagnostics.
4068 isolation, identification and characterization of entomopathogenicSheena Prem
Control of white grub using entomopathogenic nematode (Heterorhabdtidae and steinernematidae )and entomopathogenic fungi Isolation of Symbiontic bacteria of antomopathogenic nematode .
Study of antagonistic capability of trichoderma harzianum isolates against so...AL-kitab university -IRAQ
This study evaluated the antagonistic potential of two isolates of Trichoderma harzianum against seven soil-borne pathogenic fungi. In dual culture tests, T. harzianum isolate T2 showed the highest inhibitory effect against the pathogens, reducing their mycelial growth by 45.99% on average. Alternaria sp. was most inhibited by T2 at 51.18%. Volatile metabolites from T2 were also effective at inhibiting pathogen growth. Non-volatile metabolites collected from T2 cultures at different time periods and concentrations inhibited pathogen mycelial growth, with the highest (100%) concentration having the greatest effect. Microscopic analysis revealed T2 interacting with and inhibiting the pathogens through mechanisms like coiling around their
Laboratory manual for fusarium research 3rd edition Lester BurgessMarcos Buitrago
Authors of this laboratory manual are Lester W. Burgess, Brett A. Summerell, Suzanne Bullock, Kathryn P. Gott and David Backhouse.
Fusarium Research Laboratory
Department of Crop Sciences
University of Sydney
August, 1994
This study evaluated endophytic bacteria from Pinus taeda L. as potential biocontrol agents of Fusarium circinatum, the causal agent of pitch canker disease affecting pine seedlings. Five bacterial strains - four Bacillus subtilis and one Burkholderia sp. isolated from healthy pine tissue - were tested against F. circinatum in dual culture experiments. All bacteria inhibited the fungal pathogen, arresting mycelial growth within 1 cm. Thermostable metabolites from the bacterial cultures also significantly reduced fungal growth over 50% when added to media. These endophytic bacteria adapted to pine tissues showed potential as biocontrol agents to control the pitch canker fungus in nurseries and prevent disease spread.
Isolation and Identification of Fungi from fast food restaurants in Langa BazarIJEAB
A total of (218) samples from Eleven different foods were processed between October 2016 and February 2017 which include (Tomato, Chicken meat, red meat, falafel, potato, bread, eggplant, cabbage, celery, cucumber and onion). Samples were collected from 4 different fast food restaurants inoculated on Potato dextrose agar and Sabouraud Dextrose Agar. Isolated fungus identified morphologically and microscopically in accordance with standard procedures. Results showed that six fungal genera were associated with the selected fast food restaurants. The isolated fungal genera were Aspergillus sp., Alternaria sp., Mucor sp., Rhizopus sp., Saccharomyces sp., Brettanomyces sp. The number of total colonies in October were 236 and in February were 119 and the number of colonies were higher when cultured on Potato dextrose agar than Sabouraud Dextrose Agar. There was variation in the pattern of occurrence of the fungus in fast foods Aspergillus sp. appears to be the most pathogenic fungi that present in the food samples.
Evaluation of four plants compost teas against fungi responsible for Corn dam...IJEABJ
Corn (Zea mays L.) is one of the most important cereals in Côte d'Ivoire. However, Corn seeds and seedlings are susceptible to infection by a number of soilborne fungi which caused seeds decay before or after germination. The objective of this study is to evaluate the suppressive effect of Four plants compost teas (Chromolaena odorata, Ricinus communis, Nicotiana tabacum, Azadiracta indica) on Corn damping off. In vitro assays showed a most suppressive effect of C. odorata and R. communis compost teas on mycelial growth of pathogenic fungi. Results of in vivo trials showed significant reduction of Corn seedlings diseases incidence and high seed germination percent after treatment with C. odorata, R. communis and A. indica compost teas. No efficiency effect was noted with N. tabacum compost tea. This study demonstrated the usefulness of compost tea as an efficient biological tool for the control of fungi responsible of corn damping-off.
CHITINASE AS THE MOST IMPORTANT SECONDARY METABOLITES OF STREPTOMYCES BACTERISIJSIT Editor
This document summarizes a study on chitinase produced by Streptomyces bacteria. 310 Streptomyces isolates were obtained from soil samples collected across East Azerbaijan, Iran. DNA was extracted from the isolates and screened using PCR for a gene encoding family 19 chitinase, which shows significant antifungal activity. One isolate with strong antifungal effects was identified as S. griseous based on 16S rDNA sequencing and presence of the chitinase gene. The results suggest certain Streptomyces isolates have potential as biological control agents against fungal plant pathogens due to production of antifungal family 19 chitinase.
This document discusses antibiotic resistance genes found in natural environments. It begins by reviewing the early discoveries of antibiotic resistance in pathogens. It then discusses how antibiotic resistance genes are often found in environmental bacteria and can spread between species through horizontal gene transfer, especially on mobile genetic elements like plasmids. The overuse of antibiotics in agriculture, aquaculture and livestock has contributed to the increased presence of these genes in natural ecosystems. Understanding the distribution and transfer of antibiotic resistance genes in nature is important for evaluating antibiotic usage and policies.
Effect of plant growth promoting rhizobacterial (PGPR) inoculation on growth ...IJEAB
This document summarizes a study that evaluated the effects of inoculating tomato plants with three plant growth-promoting rhizobacteria (PGPR) strains. The study found that all three strains (B. cereus 2027-2, P. agglomerans 2066-7, and S. proteamaculans 2025-1) significantly increased various growth parameters of the tomato plants compared to non-inoculated controls, including aerial plant length, root length, stem diameter, chlorophyll content, and yield. The three strains were selected for further characterization of their plant growth promotion mechanisms, which found that they exhibited various combinations of abilities to solubilize phosphate, fix nitrogen, and produce ammonia, ind
Isolation and Characterization of Bacteria from Tropical SoilsNicole Rivera
This document describes a study that aimed to isolate bacteria from tropical soils in Puerto Rico that have the potential to produce antibiotics. Soil samples were collected and bacteria were isolated through serial dilution and culturing. Four isolated bacteria were purified and characterized through gram staining, testing for antibiotic production against E. coli and M. luteus, PCR amplification with 16S rRNA primers, and DNA sequencing. Two of the bacteria showed potential as antibiotic producers against M. luteus. The isolation and characterization of soil bacteria with antibiotic properties could help address the growing problem of antibiotic resistance.
This study investigated the presence of the FimH adhesin gene and biofilm formation among 24 Enterobacter isolates recovered from urine samples of cystitis patients. PCR results revealed that 18 of the 24 isolates (75%) were positive for the FimH gene. Phenotypic assays showed that 17 of the 24 isolates (70.8%) were biofilm formers. There was a significant positive correlation between biofilm formation and the presence of the FimH gene, with the gene present in 16 of the 17 biofilm-forming isolates (94.1%). The results indicate the importance of the FimH adhesin in biofilm establishment and pathogenesis of cystitis infections.
The document provides an overview of different types of entomopathogenic microbes (viruses, bacteria, fungi, nematodes, protozoa) used for insect management. It discusses the history, mode of action, symptoms caused, and examples of specific microbes used to control various insect pests for different crops. These include Bacillus thuringiensis for lepidopteran larvae, Beauveria bassiana for sucking pests, Metarhizium anisopliae for beet armyworm and rhinoceros beetle, Steinernema carpocapsea for soil-dwelling insects, and Nosema locustae for grasshoppers. The advantages of using entomopathogenic
The document discusses the effects of various bioagents on the growth of Coleus forskohlii. Key findings include:
1) Inoculation with Trichoderma viride, Pseudomonas fluorescens, and neem cake improved growth characteristics like plant height and root weight of Coleus cuttings.
2) In field conditions, inoculation with Glomus fasciculatum and Pseudomonas fluorescens led to higher yields, nutrient uptake, and forskohlin content compared to the uninoculated control.
3) Inoculation with arbuscular mycorrhizal fungi like Glomus bagyaragii and Scutellosp
Distribution of fungi, bacteria and actinomycetes in relation to cropping pat...Dr. siddhant
Eight soil samples closely situated cultivated field with varying cropping patterns have been assayed for fungi, bacteria, actinomycetes. The microbial population in different plots differed to a considerable extent. Plot with thick coverege and short term cropping pattern gave higher fungal counts. The availability of substrates for microbial growth seems to be an important factor in governing the soil microbial population. A marginal difference in moisture content and PH plays a negligible role in the determination of soil microflora.
This document discusses the challenges of classifying protists, which are eukaryotic organisms that are not plants, animals, or fungi. Protists exhibit a wide variety in their characteristics such as being photosynthetic or motile, unicellular or multicellular, and living in various habitats. They are difficult to classify because some protists share similarities with organisms from other kingdoms. While classification of protists continues to evolve, they are believed to have been the first eukaryotes and some protist ancestors gave rise to plants, animals and fungi based on their evolutionary relationships.
Prokaryotes are unicellular organisms that are classified as bacteria or archaea. They vary greatly in size, shape, movement, nutrition, and metabolism. Prokaryotes play important roles in the living world as decomposers, producers, and nitrogen fixers, recycling nutrients and producing food and biomass that supports food chains. They are ecologically important due to their diversity and roles in ecosystems.
Lab 6 isolation of antibiotic producer from soilHama Nabaz
The document outlines steps to isolate antibiotic-producing microorganisms from soil samples and determine their antimicrobial activity. Students will isolate Bacillus, Penicillium, and Actinomyces colonies on agar plates. Colonies will be streaked on plates seeded with Staphylococcus epidermidis or fungi to check for evidence of antibiosis. Colonies showing inhibition will be re-streaked with test pathogens to confirm antimicrobial activity through zone of inhibition assays. The goal is to isolate microbes producing antibiotics that could have clinical significance.
Actinomycetes are filamentous, gram-positive bacteria that have characteristics of both bacteria and fungi. They form a mycelium like fungi but have bacterial cell walls lacking chitin and cellulose. Common genera found in soil include Streptomyces, Nocardia, and Micromonospora. Streptomyces and Nocardia are important because they produce many antibiotics and can cause infections in humans. Nocardia forms branching filaments and causes pneumonia and brain infections, especially in immunocompromised individuals.
This document discusses the role of biological control agents in crop protection. It defines biological control as using natural enemies like parasites, predators, and pathogens to suppress pest populations. The three main techniques of biological control are classical, augmentative, and conservation biological control. Examples are provided of important insect pests and their corresponding natural enemies, including parasitoid wasps, green lacewings, fungi, bacteria like Bt, viruses, nematodes, and protozoa.
Biological control is a component of integrated pest management that involves using natural enemies like predators, parasitoids, and pathogens to reduce pest populations. It typically requires active human involvement. Biological control can be used against insect pests, weeds, and plant diseases. While it has advantages like being selective and inexpensive, it also has disadvantages like taking a long time to become established and not eliminating pest populations entirely.
Actinomycetes are a group of gram-positive bacteria that form branching filaments and resemble fungi. They include the genera Actinomyces, Norcardia, and Streptomyces. Actinomyces are anaerobic bacteria that are part of normal oral and gut flora and can cause actinomycosis, a chronic suppurative infection. Nocardia are partially acid-fast aerobic bacteria that are opportunistic pathogens commonly causing nocardiosis, a lung infection or disseminated disease in immunocompromised individuals. Actinomycetes play an important environmental role in soil decomposition and are a major source of antibiotics produced industrially.
Actinomycetes are filamentous, Gram-positive bacteria that can cause several types of infections in humans and animals. Actinomyces bacteria like Actinomyces israelii are anaerobic and cause cervicofacial, thoracic, abdominal, or pelvic actinomycosis by forming sulfur granules in tissues. Nocardia bacteria are aerobic, sometimes acid-fast, and can cause cutaneous, subcutaneous, or systemic infections. Streptomyces bacteria are the source of many antibiotics. Diagnosis involves identifying the sulfur granules in tissues which contain bacterial colonies and filaments. Treatment involves long-term high dose penicillin or tetracycline antibiotics.
Soil microorganisms play important roles in maintaining soil health and fertility. They are involved in nutrient cycling by decomposing organic matter, fixing nitrogen, and carrying out other biochemical processes. The main types of microbes found in soil are bacteria, actinomycetes, fungi, algae, and protozoa. Soil microbes affect soil structure, plant growth, and carry out important processes like nitrogen fixation, nutrient availability, and degradation of pollutants. However, human activities like agricultural practices, urbanization, and climate change threaten soil microbes by reducing organic matter, increasing salinity, and introducing pollutants. Proper management is needed to protect these vital soil microorganisms.
Isolation and antimicrobial activity of rhamnolipid (biosurfactant) from oil ...eSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
Prevalence, occurrence and biochemical characterization of Xanthomonas campes...INNS PUBNET
Xanthomonas campestris pv. vesicatoria the causal organism of bacterial spot in tomato results in heavy losses both in the form of quality and. In this study a survey was carried out to report the incidence of bacterial spot disease of tomato in district Swat. We reported maximum disease incidence in tehsil Kabal (71.66%), followed by Charbagh (61.66%) and Barikot (58.33%). For resistant screening a total of 13 tomato germplasms were screened against the disease. The foliar severity ranged from 3.33% to 73.33%, while severity for fruits was ranged from 18.33% to 30.66%. In case of phenotypic data the highest numbers of fruits obtained were 34, plant height 79.5cm and fruit weight was 470 grams/ten tomatoes. While the lowest average numbers of fruits were 6.67, plant height 45.7cm and fruit weight recorded was 215.67 grams/ten tomatoes. Line 1288 showed highest level of resistance followed by Red-stone. However, line 9708 showed highest susceptibility when exposed to artificial inoculation. Our study showed that bacterial spot is a major issue in some part of Pakistan and germplasm screening are linked to increased host resistance and could offer an important contribution to future integrated bacterial spot management programs.
The objectives of this study to investigate the occurrence and etiology of tomato malformation recently observed in Egypt and illustrate the responsibility of associated phytoplasma. Also, the study was extended to characterize associated phytoplasma, based on molecular techniques.
Pseudomonas aeruginosa WS-1 shows potential as a biopesticide for managing fruit rot and die back disease in chili caused by Colletotrichum capsici. In laboratory experiments, P. aeruginosa WS-1 inhibited the growth of C. capsici in dual plate cultures and produced antifungal compounds including chitinases, proteases, hydrogen cyanide, and siderophores. In greenhouse tests, treatment of chili seedlings with P. aeruginosa WS-1 prior to inoculation with C. capsici resulted in similar disease control as the fungicide carbendazim. This suggests that P. aeruginosa WS-1 could provide effective biological control of the disease under field conditions.
This document summarizes a study that evaluated the antimicrobial activity of crude culture filtrate and methanol extract of the mushroom Stereum ostrea against bacteria. Key findings:
- Crude culture filtrate of S. ostrea showed the highest inhibitory activity against both gram-positive and gram-negative bacteria based on zone of inhibition tests, with the strongest effect against Bacillus subtilis. Methanol extract also inhibited bacterial growth but to a lesser degree.
- The minimum inhibitory concentration of both crude extract and methanol extract was 20μl for B. subtilis and 30μl for other tested bacteria.
- Results indicate S. ostrea contains metabolites with potential broad-spectrum antimicrobial properties that
Potentials of Compost Tea of Certain Botanicals for Minimizing Root- Knot and...Premier Publishers
Two greenhouse experiments were conducted on eggplant to assess the impact of compost tea derived from plant residues namely rice hull (RHC), rice straw (RSC), tomato (TC), potato (PC), citrus (CC), and guava(GC) as well as city waste (CWC) compost on eggplant biomass and reproduction of Meloidogyne incognita and Rotylenchulus reniformis. Screened composts were introduced to plants as drenching application. Results indicated that percentage of increase in total plant fresh weight of eggplant infected with such nematodeswere more pronounced (P<0.05) with compost teas of RSW. Drenching the soil with RHC (Rf=0.7) and PC (Rf=0.9) were also effective in suppressing densities of M. incognita as well as number of galls, and eggs/ root. However, population densities and fecundity of R. reniformis were significantly reduced following the introduction of GC. Only, total phenol showed remarkable increment in plants treated with PC, GC and RSC compared to untreated inoculated plants.
Isolation and Screening of Soil Actinomycetes for Antimicrobial Activity OlakunleAjibola
Antimicrobial resistance in pathogens has greatly increased of late and now pose a serious public health problem globally. New antimicrobials are continuously needed to inhibit the growth of these resistant strains.
The aim of this study was to isolate and screen soil actinomycetes and evaluate their secondary metabolites for antimicrobial activities against selected pathogenic bacteria and fungi.
Bioactivity screening of Soil bacteria against human pathogenspharmaindexing
This study aimed to isolate soil bacteria with potential bioactive properties against human pathogens. 36 bacterial strains were isolated from 3 soil samples and screened against common pathogens. 14 isolates showed antibacterial activity, including against Staphylococcus aureus, Streptococcus faecalis, E. coli, Klebsiella aerogenes, Proteus vulgaris, Pseudomonas aureginosa and Salmonella typhi. The 3 most active bacterial isolates were selected for further production and isolation of their bioactive metabolites. Testing found the metabolites had prominent antibacterial effects against the clinical pathogens studied, indicating their potential as a source of new antimicrobials given the rise in drug resistance.
This study evaluated endophytic bacteria isolated from Pinus taeda L. as potential biocontrol agents of the pitch canker fungus Fusarium circinatum. Five bacterial strains - four Bacillus subtilis and one Burkholderia sp. - were tested for their ability to inhibit F. circinatum growth both through direct confrontation and through thermostable metabolites. All bacterial strains showed antagonism against F. circinatum in dual culture experiments, arresting fungal growth. Thermostable metabolites from the bacterial cultures reduced F. circinatum growth by over 50% in some cases. The results demonstrate that these endophytic bacteria and their metabolites have potential as biocontrol agents for F. circinatum affecting Pin
Effect of Trichoderma Fortified Compost on Disease Suppression, Growth and Yi...IJEAB
Trichoderma species are commonly used as effective biological control agents against phytopathogens especially the soil-borne fungi while some isolates are able to ameliorate plant growth. In the present study, Trichoderma fortified compost with different substrates were evaluated to reduce the pre-emergence and post-emergence seedling mortality, diseases of stem and root of chickpea caused by several soil-borne fungal pathogens, including Fusarium oxysporum, Rhizoctonia solani and Sclerotium rolfsii at different growth stages in the field under natural epiphytotic conditions. Among the twenty isolates of T. harzianum, Co-7 showed the most effective antagonist against the test pathogens in dual culture method. In field experiment, subsequently it was used for inoculum preparation with colonized wheat grain and mixed with well-matured decomposed composting materials like, saw dust, cow dung, tea waste, water hyacinth and poultry manure. Trichoderma fortified compost with poultry manure was found significantly effective in reducing pre-emergence and post emergence seedling mortality, disease incidence and disease severity of chickpea in the field. Interestingly, all the treatments significantly increased but Trichoderma fortified compost with poultry manure was the best to boost seed yield and quality.
First report on fusarium solani, a pathogenic fungus causing stem rot disease...Alexander Decker
This document reports on the first identification of Fusarium solani as the causal agent of stem rot disease in dragon fruits in Bali, Indonesia. Two Fusarium isolates (w1 and w2) were isolated from diseased dragon fruit stems and identified as F. solani based on morphological characteristics, molecular analysis of the internal transcribed spacer region, and Koch's postulates tests. Sequence analysis of the 18S rDNA region from both isolates showed 99% similarity to F. solani, representing the first report of this pathogenic fungus affecting dragon fruits in Bali.
The Production of Triploid Clariobranchus in Indoor HatcheryIOSR Journals
This study evaluated the interactive effects of rhizobium and virus inocula on three cowpea cultivars. The cultivars were inoculated with two rhizobium strains (R25B and IRj2180A) and two virus strains (CABMV and CYMV) at two different times. Viral inoculation significantly reduced nodulation, biomass production, and grain yields across all cultivars. Maximum reductions occurred without rhizobium inoculation. Early inoculation had a greater effect than late inoculation. The interaction of rhizobium and virus strains showed that viral severity was not reduced by rhizobium presence. Cultivar IT90K-277-2 performed best
MOLECULAR ANALYSIS OF BACTERIAL GENE CODING CHITINASE ENZYMES, FAMILY 19 STR...IJSIT Editor
The document summarizes a study on molecular analysis of bacterial genes coding for chitinase enzymes in Streptomyces bacteria. Streptomyces are known to produce chitinase enzymes that belong to families 18 and 19 and have antifungal activity. The study isolated 310 Streptomyces bacteria from soil samples in East Azerbaijan, Iran. DNA was extracted from the isolates and PCR was performed to identify isolates containing genes for family 19 chitinases. Five isolates tested positive and one showed strong antifungal activity. The gene from this isolate was cloned and sequencing identified it as a family 19 chitinase gene with 96% similarity to Streptomyces griseus. The isolate shows potential as a
Two field experiment were run at the farms of Omar AL-Mokhtar university, in order to knew the effect of some methods used to control tomato pests on soil arthropod systemic groups in organic cultivated tomato field such as (BT, algifol, methyl salicylate, neem oil), Results indicated that application of B. thuringensis and Algifol achieved the highest performance showing 100% reduction in mites and other soil arthropods systemic groups, and gave reduction 55.5 and 54.96% in both insect and total population of soil arthropods collected with pitfall traps. As far as Neemazone and Methyl salicylate increased the insect population with percentages 132.5 and 310% and total soil arthropods with 133.2% and 308.6% respectively and reduced the mites and the other arthropods population with 100%. Also results showed that the pesticides (avermectin, indoxacarb, & neemazone) increased the average number of the total soil arthropod population groups, and these pesticides showed selective effect, so that, it will be recommended that in order to preserve the beneficial predators, carnivorous and parasitoids these biological and selective pesticides in conventional tomato field should be applied.
According to the results obtained from this work, the changes in diversity and equitability and decrease or increase of percent population of soil arthropods groups were differed according to the soil arthropod groups, sampling period, applied plant protection products and system of agricultural.
1) The study evaluated the antimicrobial activity of crude culture filtrate and methanol extract of the mushroom Stereum ostrea against both Gram-positive and Gram-negative bacteria.
2) Crude culture filtrate showed higher inhibitory activity compared to methanol extract, as evidenced by larger inhibition zones. The crude filtrate was most effective against Bacillus subtilis and least effective against Klebsiella pneumoniae.
3) The minimal inhibitory concentration of both crude and methanol extracts was 20 μl for Bacillus subtilis and 30 μl for the other bacteria tested, indicating Stereum ostrea was most potent against Bacillus subtilis.
Mushroom is a type of fungus that can be found in forests and grows in winters and rainy seasons. Pleurotus ostreatus is a wild mushroom commonly found growing on dead wood in moist, shady forests. It is one of the most widely cultivated edible mushrooms worldwide and has high nutritional value. The objectives of the current study are to culture the mycelium and fruiting body of P. ostreatus and check its antibacterial activity against Bacillus subtilis and Klebsiella oxytoca using the agar disk diffusion assay method. Previous studies have shown that extracts from the mycelium and fruiting bodies of P. ostreatus produced using various solvents exhibit antibacterial
CHARACTERIZATION OF STREPTOMYCES SCABIES ISOLATESijabjournal
Potato, (Solanum tuberosum L,) have various biotic constraints in its production due to pest attack. Among these, common scab caused by streptomyces scabies in an important disease in potato which causes economic loss with respect to plant yield and quality of tubers. The present study was conducted to determine the pathogenicity, pathogenic variation, characterization of morphological, physiological and
biochemical aspects of Streptomyces specie associated with potato tubers grown in Rawalpindi district.Severity data and pathogenic variation of disease was studied by using different isolation and characterization techniques. Isolation and characterization of Streptomyces spp. From potato tubers will
guide the researchers about the causative strains of common scab of potato present in the particular area.
Effect of phytobiocides in controlling soft rot of tomatoAlexander Decker
Turmeric was the most effective phytobiocide for controlling soft rot of tomato caused by Erwinia carotovora carotovora in both laboratory and screen house experiments. In laboratory tests, turmeric produced the largest zone of inhibition against the bacteria, followed by neem and garlic. In screen house studies, tomato plants treated with turmeric grew taller and produced more fresh shoot weight than those treated with other phytobiocides or the control, indicating turmeric was best at controlling the disease and promoting plant growth. Specifically, turmeric treated plants reached 61.67 cm in height and produced 35.68 g of fresh shoot weight, more than any other treatment.
Effect of phytobiocides in controlling soft rot of tomatoAlexander Decker
1) The study tested various phytobiocides (plant-derived pesticides), including turmeric, neem, garlic, mint, oleander, and chili, for their ability to inhibit the growth of Erwinia carotovora carotovora bacteria, which causes soft rot disease in tomatoes.
2) Turmeric produced the largest zone of bacterial growth inhibition in laboratory tests, followed by neem and garlic. Screen house tests found turmeric-treated tomato plants had the highest disease resistance and growth.
3) The results suggest that phytobiocides like turmeric could serve as effective and natural agents for controlling soft rot disease in tomatoes. Turmeric was the most potent inhibitor of the bacteria.
Application of certain bacterial and fungal species for controlling Meloidogy...Premier Publishers
Bacillus subtilis (Bs) and B. megaterium (Bm), Pseudomonas fluorescens (Pf) as well as Trichoderma harziamum (Th), Trichoderma vierns (Tvr)and T. viride (Tv) were applied alone as well as in combination in pot experiment for controlling M. incognita in Cowpea. Results showed that Bs, Bp and Pf had nematicidal effects against M. incognita parameters viz., J2 in soil and roots, galls and egg-masses compared to untreated check. Bm alone had highly nematicidal activity against J2 in soil, while Bs was the best against J2 in roots, galls and egg-masses. Bs + Bm in combination was effective against M. incognita parameters. The tested species of Trichoderma also reduced the parameters of M. incognita.Th alone was highly effective in reducing the tested nematode parameters, followed by Tvr and Tv treatments. Tv + Tvr highly reduced the numbers of J2 in soil and roots, while Th+Tv+Tvr significantly reduced the galls and egg-masses numbers. All treatments also increased the growth parameters of cowpea viz., shoot length, fresh and dry shoot weights, and leaf numbers.
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Abnormalities of hormones and inflammatory cytokines in women affected with p...Alexander Decker
Women with polycystic ovary syndrome (PCOS) have elevated levels of hormones like luteinizing hormone and testosterone, as well as higher levels of insulin and insulin resistance compared to healthy women. They also have increased levels of inflammatory markers like C-reactive protein, interleukin-6, and leptin. This study found these abnormalities in the hormones and inflammatory cytokines of women with PCOS ages 23-40, indicating that hormone imbalances associated with insulin resistance and elevated inflammatory markers may worsen infertility in women with PCOS.
A usability evaluation framework for b2 c e commerce websitesAlexander Decker
This document presents a framework for evaluating the usability of B2C e-commerce websites. It involves user testing methods like usability testing and interviews to identify usability problems in areas like navigation, design, purchasing processes, and customer service. The framework specifies goals for the evaluation, determines which website aspects to evaluate, and identifies target users. It then describes collecting data through user testing and analyzing the results to identify usability problems and suggest improvements.
A universal model for managing the marketing executives in nigerian banksAlexander Decker
This document discusses a study that aimed to synthesize motivation theories into a universal model for managing marketing executives in Nigerian banks. The study was guided by Maslow and McGregor's theories. A sample of 303 marketing executives was used. The results showed that managers will be most effective at motivating marketing executives if they consider individual needs and create challenging but attainable goals. The emerged model suggests managers should provide job satisfaction by tailoring assignments to abilities and monitoring performance with feedback. This addresses confusion faced by Nigerian bank managers in determining effective motivation strategies.
A unique common fixed point theorems in generalized dAlexander Decker
This document presents definitions and properties related to generalized D*-metric spaces and establishes some common fixed point theorems for contractive type mappings in these spaces. It begins by introducing D*-metric spaces and generalized D*-metric spaces, defines concepts like convergence and Cauchy sequences. It presents lemmas showing the uniqueness of limits in these spaces and the equivalence of different definitions of convergence. The goal of the paper is then stated as obtaining a unique common fixed point theorem for generalized D*-metric spaces.
A trends of salmonella and antibiotic resistanceAlexander Decker
This document provides a review of trends in Salmonella and antibiotic resistance. It begins with an introduction to Salmonella as a facultative anaerobe that causes nontyphoidal salmonellosis. The emergence of antimicrobial-resistant Salmonella is then discussed. The document proceeds to cover the historical perspective and classification of Salmonella, definitions of antimicrobials and antibiotic resistance, and mechanisms of antibiotic resistance in Salmonella including modification or destruction of antimicrobial agents, efflux pumps, modification of antibiotic targets, and decreased membrane permeability. Specific resistance mechanisms are discussed for several classes of antimicrobials.
A transformational generative approach towards understanding al-istifhamAlexander Decker
This document discusses a transformational-generative approach to understanding Al-Istifham, which refers to interrogative sentences in Arabic. It begins with an introduction to the origin and development of Arabic grammar. The paper then explains the theoretical framework of transformational-generative grammar that is used. Basic linguistic concepts and terms related to Arabic grammar are defined. The document analyzes how interrogative sentences in Arabic can be derived and transformed via tools from transformational-generative grammar, categorizing Al-Istifham into linguistic and literary questions.
A time series analysis of the determinants of savings in namibiaAlexander Decker
This document summarizes a study on the determinants of savings in Namibia from 1991 to 2012. It reviews previous literature on savings determinants in developing countries. The study uses time series analysis including unit root tests, cointegration, and error correction models to analyze the relationship between savings and variables like income, inflation, population growth, deposit rates, and financial deepening in Namibia. The results found inflation and income have a positive impact on savings, while population growth negatively impacts savings. Deposit rates and financial deepening were found to have no significant impact. The study reinforces previous work and emphasizes the importance of improving income levels to achieve higher savings rates in Namibia.
A therapy for physical and mental fitness of school childrenAlexander Decker
This document summarizes a study on the importance of exercise in maintaining physical and mental fitness for school children. It discusses how physical and mental fitness are developed through participation in regular physical exercises and cannot be achieved solely through classroom learning. The document outlines different types and components of fitness and argues that developing fitness should be a key objective of education systems. It recommends that schools ensure pupils engage in graded physical activities and exercises to support their overall development.
A theory of efficiency for managing the marketing executives in nigerian banksAlexander Decker
This document summarizes a study examining efficiency in managing marketing executives in Nigerian banks. The study was examined through the lenses of Kaizen theory (continuous improvement) and efficiency theory. A survey of 303 marketing executives from Nigerian banks found that management plays a key role in identifying and implementing efficiency improvements. The document recommends adopting a "3H grand strategy" to improve the heads, hearts, and hands of management and marketing executives by enhancing their knowledge, attitudes, and tools.
This document discusses evaluating the link budget for effective 900MHz GSM communication. It describes the basic parameters needed for a high-level link budget calculation, including transmitter power, antenna gains, path loss, and propagation models. Common propagation models for 900MHz that are described include Okumura model for urban areas and Hata model for urban, suburban, and open areas. Rain attenuation is also incorporated using the updated ITU model to improve communication during rainfall.
A synthetic review of contraceptive supplies in punjabAlexander Decker
This document discusses contraceptive use in Punjab, Pakistan. It begins by providing background on the benefits of family planning and contraceptive use for maternal and child health. It then analyzes contraceptive commodity data from Punjab, finding that use is still low despite efforts to improve access. The document concludes by emphasizing the need for strategies to bridge gaps and meet the unmet need for effective and affordable contraceptive methods and supplies in Punjab in order to improve health outcomes.
A synthesis of taylor’s and fayol’s management approaches for managing market...Alexander Decker
1) The document discusses synthesizing Taylor's scientific management approach and Fayol's process management approach to identify an effective way to manage marketing executives in Nigerian banks.
2) It reviews Taylor's emphasis on efficiency and breaking tasks into small parts, and Fayol's focus on developing general management principles.
3) The study administered a survey to 303 marketing executives in Nigerian banks to test if combining elements of Taylor and Fayol's approaches would help manage their performance through clear roles, accountability, and motivation. Statistical analysis supported combining the two approaches.
A survey paper on sequence pattern mining with incrementalAlexander Decker
This document summarizes four algorithms for sequential pattern mining: GSP, ISM, FreeSpan, and PrefixSpan. GSP is an Apriori-based algorithm that incorporates time constraints. ISM extends SPADE to incrementally update patterns after database changes. FreeSpan uses frequent items to recursively project databases and grow subsequences. PrefixSpan also uses projection but claims to not require candidate generation. It recursively projects databases based on short prefix patterns. The document concludes by stating the goal was to find an efficient scheme for extracting sequential patterns from transactional datasets.
A survey on live virtual machine migrations and its techniquesAlexander Decker
This document summarizes several techniques for live virtual machine migration in cloud computing. It discusses works that have proposed affinity-aware migration models to improve resource utilization, energy efficient migration approaches using storage migration and live VM migration, and a dynamic consolidation technique using migration control to avoid unnecessary migrations. The document also summarizes works that have designed methods to minimize migration downtime and network traffic, proposed a resource reservation framework for efficient migration of multiple VMs, and addressed real-time issues in live migration. Finally, it provides a table summarizing the techniques, tools used, and potential future work or gaps identified for each discussed work.
A survey on data mining and analysis in hadoop and mongo dbAlexander Decker
This document discusses data mining of big data using Hadoop and MongoDB. It provides an overview of Hadoop and MongoDB and their uses in big data analysis. Specifically, it proposes using Hadoop for distributed processing and MongoDB for data storage and input. The document reviews several related works that discuss big data analysis using these tools, as well as their capabilities for scalable data storage and mining. It aims to improve computational time and fault tolerance for big data analysis by mining data stored in Hadoop using MongoDB and MapReduce.
1. The document discusses several challenges for integrating media with cloud computing including media content convergence, scalability and expandability, finding appropriate applications, and reliability.
2. Media content convergence challenges include dealing with the heterogeneity of media types, services, networks, devices, and quality of service requirements as well as integrating technologies used by media providers and consumers.
3. Scalability and expandability challenges involve adapting to the increasing volume of media content and being able to support new media formats and outlets over time.
This document surveys trust architectures that leverage provenance in wireless sensor networks. It begins with background on provenance, which refers to the documented history or derivation of data. Provenance can be used to assess trust by providing metadata about how data was processed. The document then discusses challenges for using provenance to establish trust in wireless sensor networks, which have constraints on energy and computation. Finally, it provides background on trust, which is the subjective probability that a node will behave dependably. Trust architectures need to be lightweight to account for the constraints of wireless sensor networks.
This document discusses private equity investments in Kenya. It provides background on private equity and discusses trends in various regions. The objectives of the study discussed are to establish the extent of private equity adoption in Kenya, identify common forms of private equity utilized, and determine typical exit strategies. Private equity can involve venture capital, leveraged buyouts, or mezzanine financing. Exits allow recycling of capital into new opportunities. The document provides context on private equity globally and in developing markets like Africa to frame the goals of the study.
This document discusses a study that analyzes the financial health of the Indian logistics industry from 2005-2012 using Altman's Z-score model. The study finds that the average Z-score for selected logistics firms was in the healthy to very healthy range during the study period. The average Z-score increased from 2006 to 2010 when the Indian economy was hit by the global recession, indicating the overall performance of the Indian logistics industry was good. The document reviews previous literature on measuring financial performance and distress using ratios and Z-scores, and outlines the objectives and methodology used in the current study.
For the full video of this presentation, please visit: https://www.edge-ai-vision.com/2024/06/building-and-scaling-ai-applications-with-the-nx-ai-manager-a-presentation-from-network-optix/
Robin van Emden, Senior Director of Data Science at Network Optix, presents the “Building and Scaling AI Applications with the Nx AI Manager,” tutorial at the May 2024 Embedded Vision Summit.
In this presentation, van Emden covers the basics of scaling edge AI solutions using the Nx tool kit. He emphasizes the process of developing AI models and deploying them globally. He also showcases the conversion of AI models and the creation of effective edge AI pipelines, with a focus on pre-processing, model conversion, selecting the appropriate inference engine for the target hardware and post-processing.
van Emden shows how Nx can simplify the developer’s life and facilitate a rapid transition from concept to production-ready applications.He provides valuable insights into developing scalable and efficient edge AI solutions, with a strong focus on practical implementation.
AI 101: An Introduction to the Basics and Impact of Artificial IntelligenceIndexBug
Imagine a world where machines not only perform tasks but also learn, adapt, and make decisions. This is the promise of Artificial Intelligence (AI), a technology that's not just enhancing our lives but revolutionizing entire industries.
Taking AI to the Next Level in Manufacturing.pdfssuserfac0301
Read Taking AI to the Next Level in Manufacturing to gain insights on AI adoption in the manufacturing industry, such as:
1. How quickly AI is being implemented in manufacturing.
2. Which barriers stand in the way of AI adoption.
3. How data quality and governance form the backbone of AI.
4. Organizational processes and structures that may inhibit effective AI adoption.
6. Ideas and approaches to help build your organization's AI strategy.
Removing Uninteresting Bytes in Software FuzzingAftab Hussain
Imagine a world where software fuzzing, the process of mutating bytes in test seeds to uncover hidden and erroneous program behaviors, becomes faster and more effective. A lot depends on the initial seeds, which can significantly dictate the trajectory of a fuzzing campaign, particularly in terms of how long it takes to uncover interesting behaviour in your code. We introduce DIAR, a technique designed to speedup fuzzing campaigns by pinpointing and eliminating those uninteresting bytes in the seeds. Picture this: instead of wasting valuable resources on meaningless mutations in large, bloated seeds, DIAR removes the unnecessary bytes, streamlining the entire process.
In this work, we equipped AFL, a popular fuzzer, with DIAR and examined two critical Linux libraries -- Libxml's xmllint, a tool for parsing xml documents, and Binutil's readelf, an essential debugging and security analysis command-line tool used to display detailed information about ELF (Executable and Linkable Format). Our preliminary results show that AFL+DIAR does not only discover new paths more quickly but also achieves higher coverage overall. This work thus showcases how starting with lean and optimized seeds can lead to faster, more comprehensive fuzzing campaigns -- and DIAR helps you find such seeds.
- These are slides of the talk given at IEEE International Conference on Software Testing Verification and Validation Workshop, ICSTW 2022.
Ocean lotus Threat actors project by John Sitima 2024 (1).pptxSitimaJohn
Ocean Lotus cyber threat actors represent a sophisticated, persistent, and politically motivated group that poses a significant risk to organizations and individuals in the Southeast Asian region. Their continuous evolution and adaptability underscore the need for robust cybersecurity measures and international cooperation to identify and mitigate the threats posed by such advanced persistent threat groups.
AI-Powered Food Delivery Transforming App Development in Saudi Arabia.pdfTechgropse Pvt.Ltd.
In this blog post, we'll delve into the intersection of AI and app development in Saudi Arabia, focusing on the food delivery sector. We'll explore how AI is revolutionizing the way Saudi consumers order food, how restaurants manage their operations, and how delivery partners navigate the bustling streets of cities like Riyadh, Jeddah, and Dammam. Through real-world case studies, we'll showcase how leading Saudi food delivery apps are leveraging AI to redefine convenience, personalization, and efficiency.
UiPath Test Automation using UiPath Test Suite series, part 6DianaGray10
Welcome to UiPath Test Automation using UiPath Test Suite series part 6. In this session, we will cover Test Automation with generative AI and Open AI.
UiPath Test Automation with generative AI and Open AI webinar offers an in-depth exploration of leveraging cutting-edge technologies for test automation within the UiPath platform. Attendees will delve into the integration of generative AI, a test automation solution, with Open AI advanced natural language processing capabilities.
Throughout the session, participants will discover how this synergy empowers testers to automate repetitive tasks, enhance testing accuracy, and expedite the software testing life cycle. Topics covered include the seamless integration process, practical use cases, and the benefits of harnessing AI-driven automation for UiPath testing initiatives. By attending this webinar, testers, and automation professionals can gain valuable insights into harnessing the power of AI to optimize their test automation workflows within the UiPath ecosystem, ultimately driving efficiency and quality in software development processes.
What will you get from this session?
1. Insights into integrating generative AI.
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Identification and characterization of actinomycetes for
1. Journal of Biology, Agriculture and Healthcare
ISSN 2224-3208 (Paper) ISSN 2225-093X (Online)
Vol.3, No.13, 2013
www.iiste.org
Identification and Characterization of Actinomycetes for
Biological Control of Bacterial Scab of Streptomyces scabies
Isolated from Potato
Hend Abdulhmeed Hamedo1 * Abeer Hamdy Makhlouf2
1.Faculty of Education, El Arish Suez CanalUniversity
2.Faculty of Agriculture, Minufiya University
* E-mail of the corresponding author:hend_hamedo@hotmail.com
Abstract
A novel strain of Streptomyces in Egypt (known asStreptomyces scabies) was isolated from a scabby potato
field in different regions of Egypt. The taxonomy of the organism was determined by morphology, biochemistry,
and physiological characteristics. Two bacterial strains (actinomycetes) which were isolated from soil sample
and showed antagonistic activity towards potato scab were identified using specific polymerase chain reaction
(PCR) of 16S rDNA gene. The 16SrDNA sequence analysis showed that the 1st strain belongs to the genus
Streptomyces, with closest similarity to Streptomyces avermitilis MA-4680 (100% similarity). Sequence
similarities between the 1st strain and other Streptomyces species in the same subclade ranged from 98% (with
Streptomyces griseus NBRC 13350 and Streptomyces sp. Wigar10). Keyphenotypic characteristics as well as
chemotaxonomic features of the actinomyces were congruent with thedescription of the genus Streptomyces. On
the basis of phenotypic and phylogenetic analyses. The 2nd strain identified as Actinomyces odontolyticus ATCC
17982(100% similarity). Sequence similarities between the 2nd strain and other Actenomycetes species was 98%
(with Actinomyces odontolyticusC 505).
The two identified strains showed a high level of antibiosis against pathogenic organism (Streptomyces scabies)
and achieve a significant control of disease as no sign of disease symptoms are shown on the tested varieties of
potato ( Cara and Diamond)
Keywords: Actinomycetes, biological control, Streptomyces scabies.
1. Introduction
Potato (Solanum tuberosum L.) is one of the most important vegetable crops in Egypt, for both local
consumption and exportation. It is widely cultivated and could contribute to reducing worldwide food shortages
(Han et al., 2005). One of the most important potato disease is common scabe caused by Streptomyces scabies. It
is indigenous in all potato growing areas in the world (Loria et al., 2006; Wanner, 2004). Severalspecies of
Streptomyces can cause PCS but Streptomyces scabies is considered to be predominant (Lambert and Loria,
1989). And can infects number of root crops, including radish, parsnip beet and carrot.). The disease has little
impact on total potato yield but spoils the appearance, quality, and marketability of the tubers (Johnson and
Powelson, 2008). Several methods have been used to control potato scab, including: Planting resistant varieties
and agriculture practices such as excess irrigation during tuber formation (Lapwood and Adams , 1975).
However all these methods are less effective and durable with seldom preventing disease from occurring but
generally reducing its extent of severity 3- Chemical control ,such as (3,5-D,telon) and (polyram and
mancozeb).However these chemical increase phytotexicity to freshly cut tuber and decrease in the tuber size and
yield. Therefore, we need more research into nonchemical methods of potato production seems to be justified
than other. Biological control is suitable alternative of chemical control.
Microorganisms are virtually unlimited sources of novel compounds with many medicinal and agricultural
applications. Actinomycetes, among them, hold a prominent position due to their ability to produce numerous
different metabolites such as antibiotics, enzymes and inhibitors (Xu et al., 2005). Further the discovery of novel
antibiotic and nonantibiotic lead compounds through microbial secondary metabolite screening is becoming
increasingly important. In recent years, there has been an increasing interest in discovering new agricultural
antibiotics for the protection of our living environments. The genus Streptomyces is the largest producer of
bioactive compounds (Chun et al., 1997; Labeda et al., 1997).
Actinomycetes are a gram-positive, aerobic, high GC-content and 0.5–1.0 µm in size. They are filamentous,
sporulating colonies and recognized as a transition group between primitive bacteria and fungi (Lo et al., 2002).
Among the actinomycetes groups, Streptomyces are the most popular and found worldwide in soil, and important
in soil ecology. They belong to the order Actinomycetales. Streptomyces are metabolically diverse and can
utilize almost anything as carbon source due to its ability to produce extracellular hydrolytic enzymes, including
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2. Journal of Biology, Agriculture and Healthcare
ISSN 2224-3208 (Paper) ISSN 2225-093X (Online)
Vol.3, No.13, 2013
www.iiste.org
sugars, alcohols, amino acids, organic acids, aromatic compounds and other complex substrate such as cellulose,
mannan and xylan. They are also well known for their abilities to produce antibiotics and other secondary
metabolites (Willey et al., 2008). Thus, these microorganisms have been implicated in the antagonism of a wide
variety of plant pathogenic bacteria, fungi and nematodes for their potential use as biological disease control
agents (Sahilah et al., 2010).
In the context of the information provided above, the objectives of this study have been , to evaluate the potential
of these two antibiotic-producing suppressive strains of Actinomycetes to control potato scab disease.
2 . Materials and methods
2.1 Isolation of Streptomyces scabies(pathogen)
Samples of soils and tubers of potato cultivars with scab symptoms were collected from fields of different
locations of five governorates( Kafr El-Sheikh, El-Gharbiya, El-Minufya, El-Dakahlia and El-Nobaria) in Egypt.
Isolation of actinomycetes from the scab lesions was carried out essentially as described byLawrence (1956).
Cultural, morphological microscopical and pathological properties were considered to identify the isolated
pathogens according to Burgess et al. (1994).
2.2 Morphological and physiological characterization of Streptomyces scabies (pathogen)
The morphology of the sporophores was examined microscopically, and the color of spores and colonies were
observed on oatmeal agar(OMA) after 14 days of incubation at 28°C (Holt, 1994).Production of soluble pigment
were observed after 4 days of incubation at 28°C. The ability to utilize the International Streptomyces Project
(ISP) sugars was tested on the standard basal medium (Shirling and Gottlieb, 1966).
2.3 Pathogenicity test
Pathogenicity tests were performed on potato cultivars using the methods described by Labruyere (1971).34
Strains were isolated and tested for pathogenicity. Inoculums were prepared by growing test strains for two
weeks at 30oC in 50ml tubes containing sterilized veriniculite saturated with a modified Say – solution
composed of 20gm of Sucrose, 1.2gmof L-asparagine,0.6gm of K2HPO4 and 10 gm of yeast extract per liter of
water. The healthy cultivars Cara and Diamond potato were planted in 35cm diameter pots containing sterile clay
soil mixed with 20ml of inoculum. Plants were arranged in a growth chamber as a randomized complete block
with three replicates. Uninculated controls were included in the tests. Potatoes were harvested after three months
and tubers were examined for common scab symptoms.
2.4 Screening and isolation of antagonists
Antagonists were isolated from soil rhizosphere samples of healthy potato plants producing areas at some
governorates, Egypt. The used bioagents were isolated on selected media according to the methods
recommended by Anonymous (1984), Burgess et al. (1994) and Turner et al. (1998).
2.5 Biological control of the tested microorganisms on potato scab pathogen
2.5.1 In vitro
The antagonistic activity was estimated by disc diffusion method (Barakate et al., 2002). A disc of 5mm in
diameter from every microorganisms (from 48 hours old culture) was placed on the surface of OMA plates
seeded with potato scab pathogen. The plates were incubated at 28 ºC for 24 h. The inhibition zone around the
discs indicated the antagonistic interaction.
2.5.2 In vivo
Pots of 30 cm in diameter were filled with nonsterilized clay-loam soil at rate of 8 Kg per pot. Soil infestation
with the pathogen Streptomyces scabies (control) and antagonistic microorganisms namely (Actinomycetes
odontolyticus, Streptomyces avermitilis, Streptomyces griseus, Bacillus subtilis, Bacillus thuringiensis,
Trichoderma hamatum and Trichoderma koningii) according to(Michel and Mew,1998).One tuber of either
potato cultivars(Cara and Diamond) was planted per pot(a replicate).The same eight treatment were repeated
with the other cultivar of potato. Each treatment was represented by six replicates. At harvest
the average weight of tuber and percentage of disease tuber were recorded.
2.6 Statistical analysis.
The obtained data were statistically analysed according to the method of Gomez and Gomez, (1984).
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2.7 Molecular characterization of Streptomyces avermitilis and Actinomycetes odontolyticus
2.7.1 Genomic DNA extraction from actinomycetes and Streptomyces. DNA extraction was
carried out following the CTAB method according to (Azadeh and Meon, 2009). Ten colonies of bacteria was
inoculated into 10 mL nutrient broth and incubated at 28±2°C overnight. One mL of the overnight culture was
transferred into a 1.5 mL eppendorf tube and centrifuge for 30 sec at 13,000 rpm The bacteria cells were
collected by discarding the supernatant and resuspended in 567 µL TE buffer (10 mM Tris-HCL, pH 7.4, 1 mM
EDTA and 1 L distilled water), mixing well by vortexing. Then 30 µL of 10 % SDS, 3 µL of NAOAC (sodium
acetate) pH 5.2, 100 µL of 5 M NaCl and 80 µL CTAB-NaCl were added to a total volume of 780 µL and mixed
well before incubating for 10 min in water bath at 65°C. An equal volume (780 µL) of chloroform/isoamyl
alcohol (24:1) was added to the mixture and centrifuged at 13000 rpm for 5 min to separate the phases. The clear
supernatant was transferred into a new eppendorf tube and the aqueous DNA layer was again extracted using
phenol/chloroform/isoamyl alcohol (25:24:1). This step was repeated 3 times and the supernatant pooled. The
clear supernatant was transferred into new eppendorf tube and 400 µL of isopropanol was added to precipitate
the nucleic acid. Finally the DNA was washed with 200 µL of 75% of cooled ethanol and dried at room
temperature (28±2°C) before dissolving in 100 µL Sterile Distilled Water and kept at -20°C for further analysis.
Electrophoresis was run for identifying the nucleic acids after DNA extraction in 1% of agarose gel and 1% of
TBE (Tris base, boric acid, 0.5 M EDTA solution, 1L ddH2O, pH 8.0). The products were mixed with loading
dye buffer (MBI Fermentas) in 5:1 ratio and subjected to electrophoresis at 70 volts for 1 h and 45 min. DNA
ladder 100 bp (MBI Fermentas) was used as marker. The gel was stained in ethidium bromide solution and the
bands visualized and photographed using Sony digital camira.
2.7.2 Primer design and PCR amplification. Oligonucleotide primer for 16S rDNA gene was 16S-1f (5'GCTAGTTGGTGGGGTAA-3', 17 mer) and 16S-2r (5'- GCCATCTCAGTTCGGATTG-3'; 18 mer) were
designed on the basis of the sequence of E. coli 16 S gene( corresponding to positions 247 to 263 and 1291 to
1309; E coli numbering system) (Wilems and Collins, 1993). Oligonucleotide primer for Glyophosate tolerant
gene was AroA
f (5'- GCTCTAGAAGTGTTGGAACAATATG-3'; 27 mer) and AroA r (5'TTACTCGAGTGAGAATTAAATTGATGG-3'; 33 mer) (Sun et al., 2005). Amplification reaction for bacteria
was performed in 25 µL of total volume containing 2 µL of DNA as a template, 2.5 µL of 10 PCR buffer
(Fermentas), 1.5 µL of 25 mM MgCl2 (Fermentas), 0.2 µL of 10 mMdNTPs, 0.1 µL primer oligonucleotides,
0.1 µL Taq polymerase (Fermentas) and 18.5 µL of sterilized distilled water. The amplification was performed
in a Thermal Cycler (Biometra®,T3thermocycler) (Syngene, UK) programmed for pre-denaturing of 3 min at
94°C, 30 cycles of 1min at 94°C, 1min at 58°C and 2 min at 72°C. After a final extension of 7 min at 72°C, the
samples were cooled to 4°C.
2.7.3 Nucleotide sequence analysis: The PCR products was purified using a commercial kit (QIA Quick PCR
purification kit (Qiagen, Valencia, CA), according to manufacturer's instruction. After purification, the PCR
products were sent for sequencing services at Sigma Co. Germany. The 16 S gene sequences were aligned using
BioEdit software versions 7.0.8 (http://www.mbio.nscu.edu/bioEdit/bioEdit) and searched for sequence
similarity to other sequences which are available in the NCBI database at http://www.ncbi.nih.gov using Basic
Local Alignment Search Tool (BLAST) algorithm. Multiple sequence alignments were performed on the
selected closely related sequence accessions available using bioedit software (http://bioedit.edu/).
2.7.4 Phylogenetic analysis: Phylogenetic analysis was done based on the nucleotides sequences of 16 S gene
using draw tree software provided by the Biology Workbench Program (http://workbench.sdsc.edu/).
Number of Data base JYZVMFRR015, K12FNS3P01S.
3. Results and Discussion
3.1 Isolation of Streptomyces scabies (pathogen)
Streptomyces scabies Waksman & Henrici occurs worldwide and causes common scab on potato tubers (Hooker,
1981). The type strain of S. scabies (ATCC 49173) (Lambert and Loria, 1989) is characterized by gray spores
born in spiral chains (sporophores), melanin pigment production on tyrosin-containing medium (peptone iron
agar), and utilization of all the diagnostic sugars recommended by the International Streptomyces Project (ISP)
(Shirling and Gottlieb, 1966) for identification of Streptomyces spp. S. scabies does not grow at pH 4.5 (Lambert
and Loria, 1989). Subsequently, common scab is less severe in acidic soils and does not usually occur in soils of
pH < 5.2. Severity of common scab can also be reduced by maintaining high soil moisture with irrigation and by
growing resistant cultivars (Lindholm et al., 1997).
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3.2 Description of streptomycetes isolated from scabby potato plants. Streptomyces spp. were isolated from
scabby potato plants collected from fields of different locations from many governorates, Egypt (Table 1). The
original scabby tubers showed a range of symptoms from superficial small discrete lesions covering parts of a
tuber to large, deep, coalescing raised or pitted lesions covering most or all of a tuber. They also varied in their
pathogen city on radish and on potato cultivars.
Table 1: Regions of pathogenic isolates and pathogenicity test.
Region
Isolate
source
Kafr El-Sheikh
Kafr El-Sheikh
El-Gharbiya
El-Gharbiya
El-Minufya
El-Minufya
El-Dakahlia
El-Dakahlia
El-Nobaria
El-Nobaria
Tuber
Soil
Tuber
Soil
Tuber
Soil
Tuber
Soil
Tuber
Soil
Scab type
No. of
isolates
Common
Common
Superficial
Common
Superficial
-
6
3
8
4
3
1
7
0
2
0
Pathogenicity
Potato
tubers
+
+
+
+
+
+
+
+
+
+
Radish
seedling
+
+
+
+
+
+
+
-
+ Positive reaction
- Negative reaction
3.3 Morphological and physiological characterization of Streptomyces scabies (pathogen).
Morphological observation of the 7–15 days old culture of strain isolated from potato scab is revealed that both
aerial and vegetative hyphae were abundant, well developed. Long spore chains were developed on the aerial
mycelium. The aerial mycelium was observed after the 15th day of incubation in all test media. Cultural
characteristics of the strain are shown in Table 2. Aerial mycelium of this strain was abundant, well-developed
and varied from brown to white on different tested media. The substrate hyphae varied from pale-yellow to
brown or white. Yellow diffusible pigments were produced on Yeast extract–malt extract agar media, and
melanin was produced on Peptone- Yeast extract- iron agar.
Table 2: Cultural characteristics of strain Streptomyces scabies.
Medium
Yeast extract–malt extract
agar (ISP medium 2)
Oatmeal agar (ISP medium 3)
Peptone- Yeast extract- iron agar
(ISP medium 6)
Tyrosine agar (ISP medium 7)
Nutrient agar
Czapek’s agar
Color of Aerial
mycelium
Brown
Color of Substrate
mycelium
Yellow
Production of
soluble pigment
Yellow
White
Brown
White
Brown
None
Melanin
Yellowish White
White
White
White
White
White
None
None
None
ISP, International Streptomyces Project Shirling and Gottieb (1966).
The physiological and biochemical characteristics of the same strain isolated from potato scab are indicated in
Table 3.
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Table3: Morphological and Physiological characterization of Streptomyces scabies.
Characteristic
Results
Shape of cell
Spiral hyphae
Size of cell
Long
Arial mycelium colour
Grey to brown
Colour of spores
Grey
Gram's staining
+ve
Pigment production agar
brown
Optimum temp.
28-30o
Utilization of sugar:
Mannitol
++
Fructose
+
Sucrose
++
Arabinose
+
Glucose
++
Fructose
+
Raffinose
+
Rhamnose
+
Starch hydrolysis
-
Gelatin liquefication
+
Indol formation
-
Catalase activity
+
V.P. Test
+
Methyl Red (MR)
-
Production of H2S
-
Nitrogen reaction
-
Litmus milk
+
+ positive Utilization
+ + strong positive Utilization
These results were agreed with the results shown by (Lindholm et al., 1997) which showed that S. scabie (type
strain ATCC 49173) is characterized by spiral sporophores and gray spores, production of melanin pigment on
peptone-iron agar, utilization of all ISP sugars, and pathogenicity on potato. Also color of colonies and
production of diffusiblepigments are criteria for species identification.
3.4 Pathogenicity test
Results obtained clear that potato common scabe symptoms varied according to Streptomyces scabies.
.
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3.5 Screening and isolation of antagonists
Preliminary study of 3 actinomycetes (Actinomycetes odontolyticus , Streptomyces avermitilis and Streptomyces
griseus ) , 2 bacteria (Bacillus subtilis and Bacillus thuringiensis ) and 2 fungi (Trichoderma hamatum and
Trichoderma koningii ) are isolated.
3.6 Biological control of the tested microorganisms on potato scab pathogen.
3.6.1 In vitro
The isolated organisms 3streptomycesand 2 bacteria and 2 fungi were screened against the plant pathogen
Streptomyces scabies showed antagonism activity towards it as shown in Table (4).
Table 4: Antagonistic efficiency between isolated microorganisms on potato scab.
Antagonism
Inhibition zone in mm
Actinomycetes odontolyticus
48.9
Streptomyces avermitilis
51.6
Streptomyces griseus
32.0
Bacillus subtilis
24.9
Bacillus thuringiensis
24.3
Trichoderma hamatum
19.6
Trichoderma koningii
22.9
3.6.2 In vivo
At harvest the average weight of tuber and percentage of disease tuber
was determined. The two strains that showed most clearing zone towards S. scabies (Streptomyces avermitilis
and Actinomycetes odontolyticus)were showed a high average weight of tuber and also percentage of disease on
tubers (a high biological control of disease) as shown in Table (5).
Table 5: the average weight of tuber and percentage of disease tuber.
Organisms
Average weight of tuber
% of disease tuber
Diamond
Cara
Diamond
Cara
Streptomyces scabies
76.67AB
53.57B
96.89A
94.14A
Actinomycetes
odontolyticus
79.32 A
58.38 A
0.00 F
0.00 E
Streptomyces
avermitilis
78.08 A
53.45 B
0.00 F
0.00 E
Bacillus subtilis
66.79 C
50.35 C
2.147 E
0.00 E
Bacillus thuringiensis
64.28 CD
48.67 D
9.443 D
5.803 D
Streptomyces griseus
74.01 B
53.57 B
31.51 B
22.13 B
Trichoderma koningii
62.04 D
40.15 E
16.27 C
15.16 C
Trichoderma hamatum
L.S.D
70.00 A
50.01 B
3.604 at α 0.05
147
50.12 A
23.21 B
0.689 at α 0.05
7. Journal of Biology, Agriculture and Healthcare
ISSN 2224-3208 (Paper) ISSN 2225-093X (Online)
Vol.3, No.13, 2013
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It is worthy to note that the strains Streptomyces avermitilis and Actinomycetes odontolyticus showed high
protective of antibiosis against
pathogen are subjected to further identification (morphological cultural and biochemical characteristic) (Tables 6
and7).
Table 6: Cultural characteristics of the two antagonistic strains to Streptomyces scabies
Medium
Yeast extract–malt extract
agar (ISP medium 2)
Oatmeal agar (ISP
medium 3)
Peptone- Yeast extract- iron
agar (ISP medium 6)
Tyrosine agar (ISP
medium 7)
Nutrient agar
Czapek’s agar
Color of Aerial
mycelium
Strain 1
Strain 2
Brown
Orangebrown
White to
White to
yellow
yellow
Brown
Brown
Yellowish
White
White
White to
yellow
Color of Substrate
mycelium
Strain 1
Strain 2
Yellow
Brown
Production of
soluble pigment
Strain 1
Strain 2
Yellow
Yellow
White
White
None
None
Brown
Brown
Melanin
Melanin
Yellow
White
White
None
None
Brown
Brown
White
White
Yellow
Yellow
None
None
None
None
ISP, International Streptomyces Project Shirling and Gottieb (1966).
Strain 1: Streptomyces avermitilis
strain 2: Actinomycetesodontolyticus
Morphological observation of the 7–15 days old culture of strains isolated and showed antagonism against potato
scab is revealed that both aerial and vegetative hyphae were well developed. Long spore chains were born on the
aerial mycelium. The aerial mycelium was observed after the 15th day of incubation on all test media. Cultural
characteristics of the two strains are shown in Table 5. Aerial mycelium of strain1was abundant, well-developed
and varied from white to brown on different tested media. The substrate hyphae varied from white to brown.
Aerial mycelium of strain 2 was well-developed and varied from white to orange- brown on the tested media.
The substrate hyphae varied from white to brown. The diffusible pigment melanin was observed on ISP-6
medium.
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Table 7: Morphological and Physiological characterization of the two antagonistic organisms.
Characteristic
Results
Shape of cells
Strain 1
Hyphae
Strain 2
Hyphae
Size
Long
Long
Gram's staining
+
+
Sporulation
+
+
Motility
-
-
Growth of KBA Medium
-
-
Optimum temp.
28-30o
30o
Mannitol
AG
A
Fructose
-
A
Sucrose
AG
AG
Arabinose
-
A
Glucose
A
A
Galactose
A
A
Lactose
-
-
Maltose
A
AG
Dextrose
AG
AG
Glycerol
A
A
Menthol
-
A
Raffinose
-
-
Starch hydrolysis
-
-
Gelatin liquefication
+
+
Indole formation
-
-
Catalase activity
+
+
Lipolytic activity
+
-
V.P. Test
+
+
Methyl Red (MR)
-
-
Production of H2S
-
-
-
+
+
+
Utilization of suger:
Nitratereduction
Milk coagulation
(+) Positive reaction
( -) Negative reaction
Strain 1: Streptomyces avermitilis
G : Gas
A : Acid
strain 2: Actinomycetes odontolyticus
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These results also were consistent with results obtained for 16SrDNA gene sequences DNA, indicated that one
of the two spp. is belongs to actinomycetes and the other is represented as Streptomyces sp.
3.7 Identification of the two spp. using 16SrDNA partial sequences DNA.
Two actinomycetes were examined for the specific amplification of 16S rDNA gene sequences (Azadeh and
Meon, 2009). As indicated in Table 4, the most active microorganisms against potato scab were strains 1and 2.
They were identified as Streptomyces species withmore100% sequence similarity. Strain 1and strain 2 was
identified up to species level, namely Streptomyces avermitilis MA-4680and Actinomyces odontolyticus ATCC
17982respectively.
Analysis of the 16SrDNA from Streptomyces species showed that the 1st
strain was grouped into a branch with Streptomyces coelicolor A3(similarity value of 97%; the close stneighbors.
The almost complete 16S rRNA gene sequenceof1st strain was determined in this study and has been deposited
in the GenBank datebase. This sequence was subjected to similarity searches against public databases to infer
possible phylogenetic relationships of this strain. This analysis revealed that strain was a member of the genus
Streptomyces. A neighbor-joining tree (Saitou and Nei, 1987) (Figure 1) based on 16S rDNA gene sequences
were constructed to show relationships between the strain and some other related Streptomyces species.
Bootstrap analysis was used to evaluate the tree topology of then eighbor-joining data by performing 1000
resembling (Felsenstein, 1985). Thus, based on the results of the above phenotypic and genotypic analyses, strain
1should represent specie of the genus Streptomyces, for which we propose the name Streptomyces avermitilis
MA-4680.
Streptomyces griseus NBRC 13350
Streptomyces sp SirexAA E
Streptomyces roseosporus NRRL 11379
Streptomyces lysosuperificus ATCC 31396
Streptomyces avermitilis MA 4680
Streptomyces coelicolor A 3
Streptomyces sp W 10
Streptomyces avermitilis AB 1
0.3
0.2
0.1
0.0
Figure 1. Phylogenetic dendrogram obtained by distance matrix analysis of 16S rDNA sequences, showing the
position of strain Streptomyces avermitilis MA-4680among phylogenetic neighbors. Numbers on branch nodes
are bootstrap values (1000 resamplings).
Description of Streptomyces avermitilis MA-4680
Gram positive organism both vegetative and aerial hyphae were abundant and well-developed, spore forming.
Aerial mycelium varied from white to brown. The substrate hyphae from white to brown. The diffusible pigment
melanin was observed on ISP-6 medium. Gelatin liquefaction, Catalase activity, Lipolytic activity, V.P. Test
and Milk coagulation were positive while starch hydrolysis, H2S and indole production, nitrate reduction were
negative. Glucose, mannitol, sucrose, galactose, maltose, dextrose and glycerol are utilized but not fructose,
lactose, arabinose, raffinose and mannitol.
The analysis of the 16SrDNA for 2nd strain showed Streptomyces species showed that this strain was grouped
into a branch with Actinomyces odontolyticus C 505(similarity value of 98%; the closest neighbors.The almost
complete 16S rRNA gene sequence of 2nd strain was determined in this study and has been deposited in the
GenBank datebase. This sequence was subjected to similarity searches against public databases to infer possible
phylogenetic relationships of this strain. This analysis revealed that strain was a member of the genus
actinomycetes. A neighbor-joining tree (Saitou and Nei, 1987) as shown in Figure(2) based on 16S rDNA gene
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Vol.3, No.13, 2013
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sequences was constructed to show relationships between strain 2 and some other related actinomycetes species.
Bootstrap analysis was used to evaluate the tree topology of then eighbor-joining data by performing 1000
resamplings (Felsenstein, 1985). Thus, based on the results of the above phenotypic and genotypic analyses,
strain 2 should represent a specie of the genus actinomycetes, for which we propose the name Actinomyces
odontolyticus ATCC 17982.
A coleocanis DSM 15436
Actinomyces oris H 22
Actinomyces sp F 400
Actinomyces sp F 338
A urogenitalis DSM 15434
Actinomyces sp F 310
Actinomyces sp DSM 15324
A odontolyticus C 505
A odontolyticus F 309
A odontolyticus TU 104
A odontolyticus ATCC 17982
Figure 2. Phylogenetic dendrogram obtained by distance matrix analysis of 16S rDNA sequences, showing the
position of strain Actinomyces odontolyticus ATCC 17982among phylogenetic neighbors. Numbers on branch
nodes are bootstrap values (1000 resamplings).
Description of Actinomyces odontolyticus ATCC 17982
Gram positive organism both vegetative and aerial hyphae were abundant and well-developed, spore forming
aerial mycelium of strain 2 varied from white to orange- brown on the tested media and the substrate hyphae
from white to brown. The diffusible pigment melanin was observed on ISP-6medium.Gelatineliquification,
Catalase activity, nitrate reduction, V.P. Test and Milk coagulation were positive while starch hydrolysis, H2S
and indole production were negative. Glucose, mannitol, fructose, sucrose, arabinose, galactose, maltose,
dextrose and glycerol are utilizedbut not lactose and raffinose.
Conclusion
The two identified strains Streptomyces avermitilis MA-4680 and Actinomyces odontolyticus ATCC 17982 are
showed high level of antibiosis against pathogenic organism (Streptomyces scabies) and achieve a significant
control of disease as no sign of disease symptoms are shown on the tested varieties of potato ( Cara and
Diamond).
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