Microbial toxins are toxins produced by microorganisms like bacteria, viruses and fungi. Bacterial toxins can be exotoxins, which are secreted, or endotoxins, which are part of the bacterial cell membrane. Clostridium tetani produces tetanospasmin toxin which causes tetanus, while Clostridium botulinum produces botulinum neurotoxins that cause botulism. Mycotoxins are toxins produced by fungi that can grow on foods and cause illness. Aflatoxins produced by Aspergillus can cause liver damage. Bacillus thuringiensis is a bacterium that produces crystal toxins that target insect larvae and has been
A toxin (Greek toxikon)
Poisonous substance produced by living cells or organisms
Small molecules, peptides, or proteins that capable of causing disease on contact with or absorption by body tissues interacting with biological macromolecules (enzymes or cellular receptors)
Severity: minor and acute to almost immediately deadly (as in botulinum toxin).
Microbial toxins are toxins produced by microorganisms,
including bacteria, viruses and fungi.
Abundant dispersal.
Mycorrhiza Biofertilizer is also known as VAM (Myco = Fungal + rrhiza = roots) adheres to plants rhizoids leading to development of hyphae. Hyphae boost development and spreading of white root in to soil leading to significant increase in rhizosphere. These hyphae further penetrate and form arbuscules within the root cortical. VAM fungi form a special symbiotic relationship with roots of plant that can enhance growth and survivability of colonized plants. Mycorrhiza Biofertilizer is very useful in organic farming as well as normal commercial farming
A toxin (Greek toxikon)
Poisonous substance produced by living cells or organisms
Small molecules, peptides, or proteins that capable of causing disease on contact with or absorption by body tissues interacting with biological macromolecules (enzymes or cellular receptors)
Severity: minor and acute to almost immediately deadly (as in botulinum toxin).
Microbial toxins are toxins produced by microorganisms,
including bacteria, viruses and fungi.
Abundant dispersal.
Mycorrhiza Biofertilizer is also known as VAM (Myco = Fungal + rrhiza = roots) adheres to plants rhizoids leading to development of hyphae. Hyphae boost development and spreading of white root in to soil leading to significant increase in rhizosphere. These hyphae further penetrate and form arbuscules within the root cortical. VAM fungi form a special symbiotic relationship with roots of plant that can enhance growth and survivability of colonized plants. Mycorrhiza Biofertilizer is very useful in organic farming as well as normal commercial farming
he rhizosphere is the narrow region of soil or substrate that is directly influenced by root secretions and associated soil microorganisms known as the root microbiome.
The phyllosphere is a term used in microbiology to refer to the total above-ground portions of plants as habitat for microorganisms.
Microbial interactions are ubiquitous, diverse, critically important in the function of any biological community.
The most common cooperative interactions seen in microbial systems are mutually beneficial. The interactions between the two populations are classified according to whether both populations and one of them benefit from the associations, or one or both populations are negatively affected.
Soil organic matter has long been recognized as one of the most important components in maintaining soil fertility, soil quality, and agricultural sustainability. The soil zone strongly influenced by plant roots, the rhizosphere, plays an important role in regulating soil organic matter decomposition and nutrient cycling. Processes that are largely controlled or directly influenced by roots are often referred to as rhizosphere processes. These processes may include exudation of soluble compounds, water uptake, nutrient mobilization by roots and microorganisms, rhizosphere-mediated soil organic matter decomposition, and the subsequent release of CO2 through respiration. Rhizosphere processes are major gateways for nutrients and water. At the global scale, rhizosphere processes utilize approximately 50% of the energy fixed by photosynthesis in terrestrial ecosystems, contribute roughly 50% of the total CO2 emitted from terrestrial ecosystems, and mediate virtually all aspects of nutrient cycling. Therefore, plant roots and their rhizosphere interactions are at the center of many ecosystem processes. However, the linkage between rhizosphere processes and soil organic matter decomposition is not well understood. Because of the lack of appropriate methods, rates of soil organic matter decomposition are commonly assessed by incubating soil samples in the absence of vegetation and live roots with an implicit assumption that rhizosphere processes have little impact on the results. Our recent studies have overwhelmingly proved that this implicit assumption is often invalid, because the rate of soil organic matter decomposition can be accelerated by as much as 380% or inhibited by as much as 50% by the presence of live roots. The rhizosphere effect on soil organic matter decomposition is often large in magnitude and significant in mediating plant-soil interactions.
Soils give a mechanical support to plants from which they extract nutrients. soil provides shelters for many animal types, from invertebrates such as worms and insects up to mammals like rabbits, moles, foxes and badgers. It also provides habitats colonised by a staggering variety of microorganisms. This module is about the microbial life in soils.
he rhizosphere is the narrow region of soil or substrate that is directly influenced by root secretions and associated soil microorganisms known as the root microbiome.
The phyllosphere is a term used in microbiology to refer to the total above-ground portions of plants as habitat for microorganisms.
Microbial interactions are ubiquitous, diverse, critically important in the function of any biological community.
The most common cooperative interactions seen in microbial systems are mutually beneficial. The interactions between the two populations are classified according to whether both populations and one of them benefit from the associations, or one or both populations are negatively affected.
Soil organic matter has long been recognized as one of the most important components in maintaining soil fertility, soil quality, and agricultural sustainability. The soil zone strongly influenced by plant roots, the rhizosphere, plays an important role in regulating soil organic matter decomposition and nutrient cycling. Processes that are largely controlled or directly influenced by roots are often referred to as rhizosphere processes. These processes may include exudation of soluble compounds, water uptake, nutrient mobilization by roots and microorganisms, rhizosphere-mediated soil organic matter decomposition, and the subsequent release of CO2 through respiration. Rhizosphere processes are major gateways for nutrients and water. At the global scale, rhizosphere processes utilize approximately 50% of the energy fixed by photosynthesis in terrestrial ecosystems, contribute roughly 50% of the total CO2 emitted from terrestrial ecosystems, and mediate virtually all aspects of nutrient cycling. Therefore, plant roots and their rhizosphere interactions are at the center of many ecosystem processes. However, the linkage between rhizosphere processes and soil organic matter decomposition is not well understood. Because of the lack of appropriate methods, rates of soil organic matter decomposition are commonly assessed by incubating soil samples in the absence of vegetation and live roots with an implicit assumption that rhizosphere processes have little impact on the results. Our recent studies have overwhelmingly proved that this implicit assumption is often invalid, because the rate of soil organic matter decomposition can be accelerated by as much as 380% or inhibited by as much as 50% by the presence of live roots. The rhizosphere effect on soil organic matter decomposition is often large in magnitude and significant in mediating plant-soil interactions.
Soils give a mechanical support to plants from which they extract nutrients. soil provides shelters for many animal types, from invertebrates such as worms and insects up to mammals like rabbits, moles, foxes and badgers. It also provides habitats colonised by a staggering variety of microorganisms. This module is about the microbial life in soils.
The following presentation is only for quick reference. I would advise you to read the theoretical aspects of the respective topic and then use this presentation for your last minute revision. I hope it helps you..!!
Mayur D. Chauhan
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For centuries, humans have searched for crop plants that can survive and produce in spite of insect pests.
Knowingly or unknowingly, ancient farmers selected for pest resistance genes in their crops, sometimes by actions as simple as collecting seed from only the highest-yielding plants in their fields.
With the advent of genetic engineering, genes for insect resistance now can be moved into plants more quickly and deliberately.
Bt technology is only one example of ways genetic engineering may be used to develop insect-resistant crops now and in the future.
ture, the population size of the species is regulated by environment factors. These factors are responsible for the check and balance of the living organisms. The event where living organisms leave and die without the aid of the man is termed as the natural control. Weather the abiotic factors are responsible for the natural control of the living organism; humidity and temperature are the common factors affecting this sector. Availability of the biotic factors is also a great determine for the survival of the living organisms. Many organisms attacked by pathogens causing diseases to the organisms.CONTROL OF PARASITES;METHODS; Reduction of the source of infection- the parasite is attacked within the host, thereby preventing the dissemination of the infecting agent. Therefore, a prompt diagnosis and treatment of parasitic diseases is an important component in the prevention of dissemination. Sanitary control of drinking water and food. Proper waste disposal – through establishing safe sewage systems, use of screened latrines, and treatment of night soil. The use of insecticides and other chemicals used to control the vector population. Protective clothing that would prevent vectors from resting in the surface of the body and inoculate pathogens during their blood meal. Good personal hygiene. Avoidance of unprotected sexual practices. (1Grazing management strategies in livestock (2Genetic selection (3Biological control and pasture ecology (4Vaccines (5 Dietary control-alternative forages (6 practice safe sex using condom (7 wash your hand regularly, especially after handling uncooked food or feces (8 drink clean water, including bottled water when you are traveling (9fecal exam and regular deworming 1.Grazing management strategies in livestock Management strategies include;Reduce stocking rate Here there is a positive effect on reducing parasites hence is a risk factor that affects the incidence of parasitism in livestock Use of clean grazing Grazing seasons are divided into 2 parts but if the livestock will grazing in different season there will be a dangerous to get infection hence will be at high risk.Mixed/alternate grazing Mixed grazing is based on diluting strategy, do not use cattle under 12 months.Rotational grazing Requires sub division of and careful management, rotation must be long enough for larvae from previous grazing to have died, difficult to estimate time required. 2.biological control The use of biological agents which are natural enemies of the parasites as the method of control,acts on the parasite larvae on pasture natural enemies of parasites include 1.viruses
Highly descriptive and illustrative presentation based on Biotechnology chapter 12 of NCERT class XII.
This is an important topic especially from biological research point of view.
This is to help students thoroughly understand the topic for exams as well as for future practical applications.
This presentation explores a brief idea about the structural and functional attributes of nucleotides, the structure and function of genetic materials along with the impact of UV rays and pH upon them.
The use of Nauplii and metanauplii artemia in aquaculture (brine shrimp).pptxMAGOTI ERNEST
Although Artemia has been known to man for centuries, its use as a food for the culture of larval organisms apparently began only in the 1930s, when several investigators found that it made an excellent food for newly hatched fish larvae (Litvinenko et al., 2023). As aquaculture developed in the 1960s and ‘70s, the use of Artemia also became more widespread, due both to its convenience and to its nutritional value for larval organisms (Arenas-Pardo et al., 2024). The fact that Artemia dormant cysts can be stored for long periods in cans, and then used as an off-the-shelf food requiring only 24 h of incubation makes them the most convenient, least labor-intensive, live food available for aquaculture (Sorgeloos & Roubach, 2021). The nutritional value of Artemia, especially for marine organisms, is not constant, but varies both geographically and temporally. During the last decade, however, both the causes of Artemia nutritional variability and methods to improve poorquality Artemia have been identified (Loufi et al., 2024).
Brine shrimp (Artemia spp.) are used in marine aquaculture worldwide. Annually, more than 2,000 metric tons of dry cysts are used for cultivation of fish, crustacean, and shellfish larva. Brine shrimp are important to aquaculture because newly hatched brine shrimp nauplii (larvae) provide a food source for many fish fry (Mozanzadeh et al., 2021). Culture and harvesting of brine shrimp eggs represents another aspect of the aquaculture industry. Nauplii and metanauplii of Artemia, commonly known as brine shrimp, play a crucial role in aquaculture due to their nutritional value and suitability as live feed for many aquatic species, particularly in larval stages (Sorgeloos & Roubach, 2021).
Comparing Evolved Extractive Text Summary Scores of Bidirectional Encoder Rep...University of Maribor
Slides from:
11th International Conference on Electrical, Electronics and Computer Engineering (IcETRAN), Niš, 3-6 June 2024
Track: Artificial Intelligence
https://www.etran.rs/2024/en/home-english/
Remote Sensing and Computational, Evolutionary, Supercomputing, and Intellige...University of Maribor
Slides from talk:
Aleš Zamuda: Remote Sensing and Computational, Evolutionary, Supercomputing, and Intelligent Systems.
11th International Conference on Electrical, Electronics and Computer Engineering (IcETRAN), Niš, 3-6 June 2024
Inter-Society Networking Panel GRSS/MTT-S/CIS Panel Session: Promoting Connection and Cooperation
https://www.etran.rs/2024/en/home-english/
Professional air quality monitoring systems provide immediate, on-site data for analysis, compliance, and decision-making.
Monitor common gases, weather parameters, particulates.
Nutraceutical market, scope and growth: Herbal drug technologyLokesh Patil
As consumer awareness of health and wellness rises, the nutraceutical market—which includes goods like functional meals, drinks, and dietary supplements that provide health advantages beyond basic nutrition—is growing significantly. As healthcare expenses rise, the population ages, and people want natural and preventative health solutions more and more, this industry is increasing quickly. Further driving market expansion are product formulation innovations and the use of cutting-edge technology for customized nutrition. With its worldwide reach, the nutraceutical industry is expected to keep growing and provide significant chances for research and investment in a number of categories, including vitamins, minerals, probiotics, and herbal supplements.
What is greenhouse gasses and how many gasses are there to affect the Earth.moosaasad1975
What are greenhouse gasses how they affect the earth and its environment what is the future of the environment and earth how the weather and the climate effects.
Earliest Galaxies in the JADES Origins Field: Luminosity Function and Cosmic ...Sérgio Sacani
We characterize the earliest galaxy population in the JADES Origins Field (JOF), the deepest
imaging field observed with JWST. We make use of the ancillary Hubble optical images (5 filters
spanning 0.4−0.9µm) and novel JWST images with 14 filters spanning 0.8−5µm, including 7 mediumband filters, and reaching total exposure times of up to 46 hours per filter. We combine all our data
at > 2.3µm to construct an ultradeep image, reaching as deep as ≈ 31.4 AB mag in the stack and
30.3-31.0 AB mag (5σ, r = 0.1” circular aperture) in individual filters. We measure photometric
redshifts and use robust selection criteria to identify a sample of eight galaxy candidates at redshifts
z = 11.5 − 15. These objects show compact half-light radii of R1/2 ∼ 50 − 200pc, stellar masses of
M⋆ ∼ 107−108M⊙, and star-formation rates of SFR ∼ 0.1−1 M⊙ yr−1
. Our search finds no candidates
at 15 < z < 20, placing upper limits at these redshifts. We develop a forward modeling approach to
infer the properties of the evolving luminosity function without binning in redshift or luminosity that
marginalizes over the photometric redshift uncertainty of our candidate galaxies and incorporates the
impact of non-detections. We find a z = 12 luminosity function in good agreement with prior results,
and that the luminosity function normalization and UV luminosity density decline by a factor of ∼ 2.5
from z = 12 to z = 14. We discuss the possible implications of our results in the context of theoretical
models for evolution of the dark matter halo mass function.
ISI 2024: Application Form (Extended), Exam Date (Out), EligibilitySciAstra
The Indian Statistical Institute (ISI) has extended its application deadline for 2024 admissions to April 2. Known for its excellence in statistics and related fields, ISI offers a range of programs from Bachelor's to Junior Research Fellowships. The admission test is scheduled for May 12, 2024. Eligibility varies by program, generally requiring a background in Mathematics and English for undergraduate courses and specific degrees for postgraduate and research positions. Application fees are ₹1500 for male general category applicants and ₹1000 for females. Applications are open to Indian and OCI candidates.
Salas, V. (2024) "John of St. Thomas (Poinsot) on the Science of Sacred Theol...Studia Poinsotiana
I Introduction
II Subalternation and Theology
III Theology and Dogmatic Declarations
IV The Mixed Principles of Theology
V Virtual Revelation: The Unity of Theology
VI Theology as a Natural Science
VII Theology’s Certitude
VIII Conclusion
Notes
Bibliography
All the contents are fully attributable to the author, Doctor Victor Salas. Should you wish to get this text republished, get in touch with the author or the editorial committee of the Studia Poinsotiana. Insofar as possible, we will be happy to broker your contact.
The ability to recreate computational results with minimal effort and actionable metrics provides a solid foundation for scientific research and software development. When people can replicate an analysis at the touch of a button using open-source software, open data, and methods to assess and compare proposals, it significantly eases verification of results, engagement with a diverse range of contributors, and progress. However, we have yet to fully achieve this; there are still many sociotechnical frictions.
Inspired by David Donoho's vision, this talk aims to revisit the three crucial pillars of frictionless reproducibility (data sharing, code sharing, and competitive challenges) with the perspective of deep software variability.
Our observation is that multiple layers — hardware, operating systems, third-party libraries, software versions, input data, compile-time options, and parameters — are subject to variability that exacerbates frictions but is also essential for achieving robust, generalizable results and fostering innovation. I will first review the literature, providing evidence of how the complex variability interactions across these layers affect qualitative and quantitative software properties, thereby complicating the reproduction and replication of scientific studies in various fields.
I will then present some software engineering and AI techniques that can support the strategic exploration of variability spaces. These include the use of abstractions and models (e.g., feature models), sampling strategies (e.g., uniform, random), cost-effective measurements (e.g., incremental build of software configurations), and dimensionality reduction methods (e.g., transfer learning, feature selection, software debloating).
I will finally argue that deep variability is both the problem and solution of frictionless reproducibility, calling the software science community to develop new methods and tools to manage variability and foster reproducibility in software systems.
Exposé invité Journées Nationales du GDR GPL 2024
Phenomics assisted breeding in crop improvementIshaGoswami9
As the population is increasing and will reach about 9 billion upto 2050. Also due to climate change, it is difficult to meet the food requirement of such a large population. Facing the challenges presented by resource shortages, climate
change, and increasing global population, crop yield and quality need to be improved in a sustainable way over the coming decades. Genetic improvement by breeding is the best way to increase crop productivity. With the rapid progression of functional
genomics, an increasing number of crop genomes have been sequenced and dozens of genes influencing key agronomic traits have been identified. However, current genome sequence information has not been adequately exploited for understanding
the complex characteristics of multiple gene, owing to a lack of crop phenotypic data. Efficient, automatic, and accurate technologies and platforms that can capture phenotypic data that can
be linked to genomics information for crop improvement at all growth stages have become as important as genotyping. Thus,
high-throughput phenotyping has become the major bottleneck restricting crop breeding. Plant phenomics has been defined as the high-throughput, accurate acquisition and analysis of multi-dimensional phenotypes
during crop growing stages at the organism level, including the cell, tissue, organ, individual plant, plot, and field levels. With the rapid development of novel sensors, imaging technology,
and analysis methods, numerous infrastructure platforms have been developed for phenotyping.
2. Microbial Toxins
A toxin (Greek toxikon)
poisonous substance produced by living cells or organisms
small molecules, peptides, or proteins that capable of
causing disease on contact with or absorption by body tissues
interacting with biological macromolecules (enzymes or
cellular receptors)
severity: minor and acute to almost immediately deadly (as
in botulinum toxin).
Microbial toxins are toxins produced by microorganisms,
including bacteria, viruses and fungi.
Ubiquitous distribution.
3. Different Types of Microbial Toxins
Bacterial Toxins:
Exotoxins : generated by the bacteria and actively
secreted.
Endotoxins :are part of the bacteria itself( bacterial
outer membrane) and it is not released until the bacteria
is killed by the immune system.
Clostridium tetani :
rod-shaped, anaerobic , Gram-positive
found as spores in soil or in the gastrointestinal tract of
animals.
biological toxin, tetanospasmin
the causative agent of tetanus, a disease characterized
by painful muscular spasms that can lead to respiratory
failure .
4. Clostridium botulinum
gram-positive, rod-shaped
produces neurotoxins, known as botulinum neurotoxins types
A-G,
that cause the flaccid muscular paralysis seen in botulism.
Obligate anaerobic spore-former, endospores
commonly found in soil.
Pseudomonas fluorescens
Gram-negative, rod-shaped ,an obligate aerobe
has multiple flagella
found in the soil and in water.
strains (CHA0 or Pf-5, ) present biocontrol properties, protecting the roots of
some plant species against parasitic fungi such as Fusarium or Pythium, as
well as some phytophagous nematodes.
produce the secondary metabolite 2,4-diacetylphloroglucinol
(2,4-DAPG )
5. Mycotoxin:
Fungi produces two categories of toxins.
One of those produced by some mushrooms (such as Amanita
phalloids, Cortinarius orellanus, Coprinus atrementarius, Inocybe
sp., etc) which are consumed directly as food.
The poisoning caused by mushrooms is called “mycetismus”.
Second type of toxins is those produced by certain molds, which
grow on other food products.
These are reffered as “mycotoxins”. Mycotoxins may be mutagenic
or carcinogenic and may display specific organ toxicity.
6. Mycotoxins are produced by fungi as secondary metabolites at the
end of the exponential growth phase.
Mycotoxins are generally synthesized via polypeptide route.
Induction of mycotoxicoses i.e. disease of animals and humans caused
by the consumption of feed and food invaded by toxin producing fungi,
thus pose serious threat to human and animal health.
Most mycotoxicoses are caused by common and wide spread fungi as
Aspergillus, Fusarium, Penicillum and Stachybotrys. Aspergillus and
Penicillum produces toxins mostly in stored seeds, hay or commercially
processed food and feeds.
Fusarium produces toxins on corn and other stored grains and
Stachbotrys on straw, hay and other cellulose products used used as
fodder or bedding for animals.
7. Aflatoxins are naturally occurring mycotoxins. Aflotoxins may
be produced in infected cereal grains, most legumes, groundnut
and other seeds.
The moisture content in the seed or grains is the most
important factor determining whether the aflotoxins producing
fungus will grow or not.
Moisture content >14% favours fungal growth. Aflotoxin , a
polyketide toxin, is a metabolic product of Aspergillus flavus ,
Aspergillus parasiticus and other Aspergillus species.
The polyketides are derived from acetyl CoA and melonyl
CoA. Aflotoxins consists of several chromatographically
distinguishable components such as aflotoxin B1 ,B2, G1,G2,etc.
The main target organ in mammals is the liver so aflatoxicosis
is primarily a hepatic disease.
8. Fusarium toxins:
Several species of Fusarium produce zearalenone and trichothecene
toxins in molded corn. zearalenone (F-2 mycotoxin) is produced by
F.roseum, F.graminearum, F.oxisporum, F.moniliforme and F.tricinctum.
It causes ‘estrogenic syndrome’ in swine.
9. Ergot alkaloids:
These are produced by Claviceps purpurea and other Claviceps
species which grow in the heads of cereal grains, produce sclerotinia
and replace grains with the bodies containing ergot alkaloids.
These fungi produce an extensive series of alkaloids , based on the
aminoacid trptophan, dimethyl-allyl pyrophosphate and methyl
methionine and form ergoline ring structure.
The alkaloids are structurally related to lysergic acid diethylamide
(LSD),a well known psycho-active drug. Ergots cause abortion and
smooth muscle contraction which sometimes may lead to the loss of
limbs.
10. Patulin:
It is polyketide carcinogenic toxin produced by Penicillium
urticae, P.patulum, P.griseofulvum, P.claviforme, etc,.
It is biosynthesized through acetate – malonate pathway. It is
toxic to bacteria and some fungi, higher plants and animals.
Stachybotrys toxins:
These toxins are produced thye species of stachybotrys on
straw, hay, other fodders and animal feeds, etc. stachybotrys
toxins cause diseases like haemorrhage, necrosis and general
cell damage in domesticated animals.
11. Alternaria toxins:
Several species of Alternaria produce toxins that have
been found in apple, tomato , blue berry, etc. the toxins
produced include alternariol, monomethl ether, alternune,
tenuazoic acid and altertoxin.
Aspergillus and Penicillium produce many other kinds of
toxins such as yellow rice toxins and tremorgenic toxins.
Ochratoxins produced by A.ochraceus causes fatty liver
disease.
12. Effects of Mycotoxins(aflatoxin B1 )
Mycotoxins (100 or 200 μg kg−1 soil) significantly decreased nodule
number, nodule fresh weight and total nitrogenase activity, leading to
reductions in dry matter accumulation and nitrogen yield of the bean
suppressed specific nitrogenase activity.
NADH-dependent glutamate dehydrogenase (NADH-GDH) as well
as glutamate synthase (NADH-GOGAT) activities.
inhibited synthesis of leghaemoglobin, carbohydrate and protein in
the nodule cytosol.
interference with normal nodule physiology and function.
13. Bacillus thuringiensis (Bt)
Gram-positive, soil-dwelling bacterium
naturally in the gut of caterpillars ( moths, butterflies, )
aerobes capable of producing endospores.
During sporulation produce crystal proteins (proteinaceous
inclusions), δ-endotoxins ( crystal proteins or Cry proteins),
encoded by cry genes(located on the plasmid)
14. specific activities against insect species of orders
Lepidoptera (moths and butterflies),
Diptera (flies and mosquitoes),
Coleoptera (beetles),
hymenoptera(wasps, bees, ants and sawflies)
nematodes
use as insecticides, genetically modified crops using Bt
genes.
biological alternative to a pesticides.
many crystal-producing Bt strains that do not have
insecticidal properties.
used as specific insecticides under trade names
such as Dipel and Thuricide
16. Mechanism of Toxicity
1.Ingestion: ICP (Insecticidal crystalline proteins) spore
complexes of Bt by susceptible insect larvae
2. Activation: alkaline pH, in midgut ICP is dissociated to
protoxin form
protoxin is then activated to holotoxin by gut
proteases.
3.Paralysis: gut becomes paralysed
larva ceases to feed
17. 4.Binding:Binding of the ICP to receptors
major determinant of ICP specificity
5.Pore formation: midgut epithelial cells damaged,
the haemolymph and gut contents can mix.
results in favourable conditions for the Bt spores to
germinate.
vegetative cells of Bt and the pre-existing microorganisms
in the gut proliferate in the haemocoel causing septicaemia,
6.Mortality of larvae
18. Effects of Bt Toxins on Soil Ecosystem
Microbial communities- part of complex food webs together
with soil dwelling invertebrates( earthworms , collembolans
,mites ,woodlice ,nematodes )
Carry out processes in soil ecosystem(Nutrient cycling,
decomposition of organic matter, decomposition of agricultural
chemicals , improvement of soil structure).
Mediators of stability of food webs.
Generally, few or no toxic effects of cry protein on invertebrates,
microorganisms and activity of various enzymes in soil.