The study aimed to match oral bacterial DNA from human bite marks to the biter's mouth. Five volunteers bit themselves and their bite marks were swabbed over time. Bacterial DNA was extracted from swabs and volunteers' mouths but could not be conclusively matched. One of five dental impressions was correctly matched to a bite mark photo. More time is needed but microbial analysis of bite marks may help forensics if traditional evidence is lacking.
Identification of Unknown Bacteria Extracted from Flagstaff, AZVictoria Ziegler
This document summarizes an experiment to identify an unknown bacteria extracted from soil in Flagstaff, Arizona. A cotton swab sample was taken from a twig and various tests were performed on the isolated bacteria, including staining, biochemical tests, and analysis of growth patterns. Through purification and isolation techniques, morphological analysis using stains, and tests of enzymatic activity and metabolic processes, the student aimed to determine the specific genus and species of the unknown bacteria. The results of the staining, catalase, oxidase, carbohydrate fermentation, oxygen requirement, and nitrate reduction tests would provide information to identify the bacteria.
Resistance to antimicrobials by pathogenic microorganisms has raised serious global clinical concerns in recent times. The present study aimed at detection of β-lactam resistance genes in S. aureus isolates from women with symptomatic and asymptomatic cases of urinary tract infections in Nasarawa state, Nigeria. A total of 200 non-repetitive midstream urinal samples were analysed and 50 (29%) bacterial isolates were identified as S. aureus. The susceptibility profile of the bacterial isolates to tested antibiotics was Nitrofurantoin (74.1%), Gentamicin (72.4%), Ciprofloxacin (65.5%), Ofloxacin (56.9), Augmentin (36.2%), Cotrimozazole (29.3%), Ampicillin (27.6%), Erythromycin (25.8%), Ceftazidine (20.7%) and Cefurozime (10.3%). Thirteen bacterial isolates were found to be resistant to all β-lactam antibiotics tested, out of which 7 were confirmed β-lactamase producers using the acidometric and iodometric methods. The detection of β-lactamase genes (blaZ, blaI and blaR1) was carried out and only five of the isolates were found to be expressing the blaI genes. This research finding suggests that β-lactam resistance by S. aureus may not be dependent only on the blaZ, blaI and blaR1 genes.
How to write an unknown lab report in microbiologygeneralarnit1
The document provides guidelines for writing an unknown lab report in microbiology. It discusses the general format and structure, including using the passive voice and past tense. It describes the typical sections - title page, introduction, materials and methods, results, discussion/conclusion, and references. For the materials and methods section, it recommends referencing the lab manual procedures. The results section should include biochemical test results in a table and identification flowchart. The discussion/conclusion interprets the results and identifies the unknown microorganism.
This master's seminar presentation speaks about the role of bacteriophage in the management of different plant diseases.
It deals with the history and discovery of bacteriophages up to current research studies and usage.
The researchers collected blue crabs from a polluted wetland (experimental group) and unpolluted dock (control group) to compare bacteria levels in their blood. They found higher bacteria counts in the male crab from the polluted site, including a salt-tolerant Bacillus species and Micrococcus species. However, further samples did not produce reliable bacteria counts, possibly due to differences in crab size and sex between trials. The study aimed to correlate environmental pollution to bacteria levels in crab blood but yielded inconclusive results requiring more sampling.
The document describes identifying Salmonella typhimurium from a mixed culture using differential tests. A pure culture of the Gram-negative bacteria was obtained and tested on five types of differential media. The results identified the bacteria as S. typhimurium based on its ability to ferment glucose and perform mixed acid fermentation, utilize citrate, reduce sulfur and be motile on SIM media. Standard differential testing using affordable media can successfully identify bacterial species from mixed cultures.
Genotyping and subgenotyping of Trichophyton rubrum isolated from dermatophyt...iosrjce
IOSR Journal of Pharmacy and Biological Sciences(IOSR-JPBS) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of Pharmacy and Biological Science. The journal welcomes publications of high quality papers on theoretical developments and practical applications in Pharmacy and Biological Science. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Development and comparison of capture enzyme linked immunosorbent assay and i...Alexander Decker
This document describes a study that developed and compared a capture enzyme-linked immunosorbent assay (C-ELISA) test and an indirect immunofluorescent test (IIFA) for detecting Nairobi sheep disease virus (NSDV). NSDV was purified from an infected sheep sample and used to immunize animals to produce antibodies. A C-ELISA was developed using these antibodies. 20 samples were tested with both C-ELISA and IIFA (the current standard), finding 95% agreement between the tests. C-ELISA had higher specificity (100% vs IIFA 80%) and was more efficient than IIFA which requires skilled personnel and tissue culture facilities. The study demonstrated C-ELISA as a viable
Identification of Unknown Bacteria Extracted from Flagstaff, AZVictoria Ziegler
This document summarizes an experiment to identify an unknown bacteria extracted from soil in Flagstaff, Arizona. A cotton swab sample was taken from a twig and various tests were performed on the isolated bacteria, including staining, biochemical tests, and analysis of growth patterns. Through purification and isolation techniques, morphological analysis using stains, and tests of enzymatic activity and metabolic processes, the student aimed to determine the specific genus and species of the unknown bacteria. The results of the staining, catalase, oxidase, carbohydrate fermentation, oxygen requirement, and nitrate reduction tests would provide information to identify the bacteria.
Resistance to antimicrobials by pathogenic microorganisms has raised serious global clinical concerns in recent times. The present study aimed at detection of β-lactam resistance genes in S. aureus isolates from women with symptomatic and asymptomatic cases of urinary tract infections in Nasarawa state, Nigeria. A total of 200 non-repetitive midstream urinal samples were analysed and 50 (29%) bacterial isolates were identified as S. aureus. The susceptibility profile of the bacterial isolates to tested antibiotics was Nitrofurantoin (74.1%), Gentamicin (72.4%), Ciprofloxacin (65.5%), Ofloxacin (56.9), Augmentin (36.2%), Cotrimozazole (29.3%), Ampicillin (27.6%), Erythromycin (25.8%), Ceftazidine (20.7%) and Cefurozime (10.3%). Thirteen bacterial isolates were found to be resistant to all β-lactam antibiotics tested, out of which 7 were confirmed β-lactamase producers using the acidometric and iodometric methods. The detection of β-lactamase genes (blaZ, blaI and blaR1) was carried out and only five of the isolates were found to be expressing the blaI genes. This research finding suggests that β-lactam resistance by S. aureus may not be dependent only on the blaZ, blaI and blaR1 genes.
How to write an unknown lab report in microbiologygeneralarnit1
The document provides guidelines for writing an unknown lab report in microbiology. It discusses the general format and structure, including using the passive voice and past tense. It describes the typical sections - title page, introduction, materials and methods, results, discussion/conclusion, and references. For the materials and methods section, it recommends referencing the lab manual procedures. The results section should include biochemical test results in a table and identification flowchart. The discussion/conclusion interprets the results and identifies the unknown microorganism.
This master's seminar presentation speaks about the role of bacteriophage in the management of different plant diseases.
It deals with the history and discovery of bacteriophages up to current research studies and usage.
The researchers collected blue crabs from a polluted wetland (experimental group) and unpolluted dock (control group) to compare bacteria levels in their blood. They found higher bacteria counts in the male crab from the polluted site, including a salt-tolerant Bacillus species and Micrococcus species. However, further samples did not produce reliable bacteria counts, possibly due to differences in crab size and sex between trials. The study aimed to correlate environmental pollution to bacteria levels in crab blood but yielded inconclusive results requiring more sampling.
The document describes identifying Salmonella typhimurium from a mixed culture using differential tests. A pure culture of the Gram-negative bacteria was obtained and tested on five types of differential media. The results identified the bacteria as S. typhimurium based on its ability to ferment glucose and perform mixed acid fermentation, utilize citrate, reduce sulfur and be motile on SIM media. Standard differential testing using affordable media can successfully identify bacterial species from mixed cultures.
Genotyping and subgenotyping of Trichophyton rubrum isolated from dermatophyt...iosrjce
IOSR Journal of Pharmacy and Biological Sciences(IOSR-JPBS) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of Pharmacy and Biological Science. The journal welcomes publications of high quality papers on theoretical developments and practical applications in Pharmacy and Biological Science. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Development and comparison of capture enzyme linked immunosorbent assay and i...Alexander Decker
This document describes a study that developed and compared a capture enzyme-linked immunosorbent assay (C-ELISA) test and an indirect immunofluorescent test (IIFA) for detecting Nairobi sheep disease virus (NSDV). NSDV was purified from an infected sheep sample and used to immunize animals to produce antibodies. A C-ELISA was developed using these antibodies. 20 samples were tested with both C-ELISA and IIFA (the current standard), finding 95% agreement between the tests. C-ELISA had higher specificity (100% vs IIFA 80%) and was more efficient than IIFA which requires skilled personnel and tissue culture facilities. The study demonstrated C-ELISA as a viable
This experiment aimed to generate Escherichia coli resistant to bacteriophage T1 and classify mutations. Plaque assays to isolate resistant mutants were unsuccessful, yielding no plaques. Regrowth of mutants from previous research was successful, as was MRVP testing to confirm the regrown cultures were E. coli. Genomic DNA was isolated from positive mutant cultures and will undergo PCR amplification and analysis. In summary, the experiment generated no new resistant mutants but validated previous work characterizing E. coli mutations that confer resistance to bacteriophage infection.
The study characterized the Campylobacter jejuni IAL 2383 strain isolated from humans in Brazil. They found that the strain harbored important virulence genes and expressed major virulence factor transcripts. It grew better at 41°C than 37°C, indicating ability to colonize avian hosts. The strain was sensitive to most antibiotics tested and could serve as an experimental model for interactions with host cells and acquisition of antibiotic resistance.
This document describes the development of a real-time PCR assay to detect and quantify Vibrio alginolyticus using the groEL gene. A species-specific primer was designed based on alignments of groEL gene sequences. Testing showed the primer only amplified V. alginolyticus and not other Vibrio or non-Vibrio strains. The assay was sensitive enough to detect as few as 10 cells per ml and was used to quantify V. alginolyticus artificially inoculated into shellfish and shrimp samples.
The document summarizes a Quantiswab study conducted by an intern to verify the recovery of microorganisms using the Quantiswab technique. Five organisms (Aspergillus brasiliensis, Bacillus subtilis, Candia albicans, Pseudomonas aeruginosa, Staphylococcus aureus) were inoculated onto steel coupons and allowed to dry. The coupons were then swabbed using Quantiswabs and the swabs processed in different ways to quantify recovery percentages. Unfortunately, none of the recovery percentages met the target 70-130% range. The intern concluded it was a valuable learning experience but that more work is needed to optimize the Quantiswab technique for higher recovery
Since Staphylococcus nepalensis were reported for the first time from Nepalese animal specimen, and have been reported from human specimens elsewhere, this bug can be a threat in our part. Protocols must be designed aimed at their identification in our laboratory during microbiological analysis of clinical specimens.
Isolation and Identification of MDRO's in the Rio Grande River PosterKayleeWersant
Antibiotic resistant bacteria was found in water samples from the Rio Grande River. 19 out of 34 isolated bacterial samples showed resistance to at least 4 classes of antibiotics. Common antibiotic resistant bacteria isolated included E. coli and Klebsiella pneumoniae. The presence of antibiotic resistant bacteria in the river implies that antibiotic resistance is a growing issue affecting an important water source used for agriculture, recreation, and domestic purposes in Texas, Colorado, and New Mexico.
This document summarizes a study that examined soil samples from 17 bat hibernacula caves in Oklahoma for the presence of Pseudogymnoascus destructans, the fungus that causes white-nose syndrome. 83 soil samples were tested using real-time polymerase chain reaction analysis and none were found to contain genetic material from P. destructans. The study suggests that P. destructans has not yet reached Oklahoma based on these results and previous negative tests of bats in the state.
The document outlines Stephanie Roto's thesis defense presentation on her research investigating the effects of feeding Original-XPCTM on modulating the cecal microbiota and inhibiting Salmonella survival in poultry hosts. Her research included in vitro assays examining Salmonella survival when treated with XPC and in vivo feeding trials analyzing how XPC impacts the cecal microbiota and Salmonella prevalence at different ages. Her results showed that XPC treatment led to a more rapid decrease in Salmonella survival by 24 hours and did not significantly alter the cecal microbial diversity between treatments but did increase with bird maturity.
This document describes the isolation and characterization of a new giant virus called Cedratvirus. Key points:
- Cedratvirus was isolated from an environmental sample in Algeria using Acanthamoeba castellanii.
- It has an ovoid shape with a cork structure at each end, resembling Pithovirus sibericum but with a unique double cork feature.
- The 589kb genome is most closely related to the pithovirus genomes, sharing over 100 genes, but with only 21% of genes involved in best reciprocal hits, indicating genetic distance from known pithoviruses.
PREVALENCE AND ANTIMICROBIAL SUSCEPTIBILITY OF ESBL IN SOKOTO PDFNuhu Tanko
This study examined the prevalence and antimicrobial susceptibility of extended-spectrum beta-lactamase (ESBL)-producing gram-negative uropathogens in Sokoto, Nigeria. 365 urine samples were collected and analyzed between November 2014 and February 2015. Gram-negative uropathogens made up 60.9% of positive cultures. The most common isolates were E. coli (29.7%) and Salmonella arizonae (23.4%). 15 isolates (23.3%) were confirmed as ESBL producers, with E. coli and Enterobacter gergoviae being the most common. The isolates showed high resistance to cotrimoxazole but high susceptibility to nitrofurantoin. This study demonstrates
This document describes the development and validation of a new quantitative PCR (qPCR) assay to estimate total bacterial load in stool samples.
1) The assay targets a conserved region of the 16S rRNA gene using new primers and a probe to generate a shorter amplicon compatible with clinical diagnostics.
2) Testing on 500 liquid and 50 solid stool samples showed the assay accurately measured total bacterial load compared to culture-based methods.
3) The new assay addresses previous issues with non-specific priming and amplification bias, and provides a standardized method for quantifying total bacteria in complex clinical samples.
Seshu K. Gudlavalleti has over 20 years of experience in vaccine development and microbial biochemistry. He received his PhD from Jawaharlal Nehru University and has held positions at the FDA, Emory University, and currently works as Chief Scientist at JN Medical Corporation developing meningococcal conjugate vaccines. He has authored over 15 publications and holds one US patent related to his work developing vaccines and characterizing microbial proteins and polysaccharides.
Dr. Ying Fang - Emerging swine disease diagnostics and characterization: conn...John Blue
Emerging swine disease diagnostics and characterization: connecting basic research to real-world applications - Dr. Ying Fang, Kansas State University, from the 2017 North American PRRS/National Swine Improvement Federation Joint Meeting, December 1‐3, 2017, Chicago, Illinois, USA.
More presentations at http://www.swinecast.com/2017-north-american-prrs-nsif-joint-meeting
Detection and Subtype Identification of Blastocystis Isolates from Wastewater...gon0603
Presented during the 6th Asian-Pacific Organization for Cell Biology (APOCB) International Congress, EDSA Shangri-La, Manila, Philippines, 25 to 28 February 2011
The document describes a study that tested a rapid saturated phenol screening method for detecting plasmids in bacteria. Several bacterial isolates were screened for plasmids using both the alkaline lysis method and the rapid screening method. The rapid method more quickly and consistently detected plasmids in three isolates. It is a simple, efficient alternative to alkaline lysis screening for plasmid presence or absence and allows screening many samples in a short time.
Richelle SOPKO is a biologist with expertise in kinase signaling pathways. She has extensive experience using techniques like proteomics, RNAi, transgenic animals, and mass spectrometry to identify kinase targets and characterize cellular signaling. Currently a postdoctoral fellow at Harvard Medical School, her work involves mapping phosphorylation pathways in Drosophila and examining crosstalk between survival pathways in blood cells.
10 the influence of environmental bacteria in freshwater stingraypryloock
The document discusses a study on bacteria found in the mucus of freshwater stingrays (Potamotrygon motoro) and river water in Brazil, and the ability of these bacteria to cause infections. The study identified bacteria from stingray mucus and river water samples, finding mostly gram-negative bacteria like Aeromonas spp. and Enterobacter cloacae. Some bacteria produced toxins that damaged human cells in lab tests. Antibiotic testing found that 68% of bacterial isolates were resistant to at least one antibiotic. While stingray venom was toxic to cells, it did not increase bacterial growth. In summary, bacteria from stingray mucus and river water could transfer into wounds and cause severe secondary infections.
Detection of Wuchereria bancrofti DNA in paired serum and urine samples using...dewisetiyana52
This study aimed to standardize PCR-based systems for the diagnosis of lymphatic filariasis using serum and urine samples. Paired biological samples were collected from 20 individuals known to be infected with Wuchereria bancrofti. Conventional and semi-nested PCR assays were optimized to detect W. bancrofti DNA. The internal PCR system was able to detect as little as 10 fg of W. bancrofti DNA and detected infection in all 20 patients using both serum and urine samples. In contrast, the semi-nested PCR only detected infection in 2 of the 20 patients. This study demonstrates the potential of using a simple internal PCR system and urine samples for the diagnosis of W. b
1. The study analyzed 30 Vibrio cholerae O1 isolates from patients in Delhi, India from 2012-2014 using mismatch amplification mutation assay (MAMA) PCR to identify the ctxB genotype.
2. All isolates were biochemically identified as V. cholerae El Tor serotype Ogawa. MAMA PCR results showed that all isolates carried the ctxB gene of the classical biotype, though they were phenotypically El Tor.
3. This identifies an "altered El Tor" variant circulating in Delhi that displays characteristics of both classical and El Tor biotypes in possessing the classical ctxB gene despite being phenotypically El Tor.
FLUID MECHANICS
Fluid mechanics is the branch of physics which involves the study of fluids (liquids, gases, and plasmas) and the forces on them. Fluid mechanics can be divided into fluid statics, the study of fluids at rest; and fluid dynamics, the study of the effect of forces on fluid motion. It is a branch of continuum mechanics, a subject which models matter without using the information that it is made out of atoms; that is, it models matter from a macroscopic viewpoint rather than from microscopic. Fluid mechanics, especially fluid dynamics, is an active field of research with many problems that are partly or wholly unsolved. Fluid mechanics can be mathematically complex, and can best be solved by numerical methods, typically using computers. A modern discipline, calledcomputational fluid dynamics (CFD), is devoted to this approach to solving fluid mechanics problems. Particle image velocimetry, an experimental method for visualizing and analyzing fluid flow, also takes advantage of the highly visual nature of fluid flow.
The study of fluid mechanics goes back at least to the days of ancient Greece, when Archimedes investigated fluid statics and buoyancy and formulated his famous law known now as the Archimedes' principle, which was published in his work On Floating Bodies - generally considered to be the first major work on fluid mechanics. Rapid advancement in fluid mechanics began with Leonardo da Vinci (observations and experiments), Evangelista Torricelli (invented the barometer), Isaac Newton (investigated viscosity) and Blaise Pascal (researched hydrostatics, formulated Pascal's law), and was continued by Daniel Bernoulli with the introduction of mathematical fluid dynamics in Hydrodynamica .
Fluid statics or hydrostatics is the branch of fluid mechanics that studies fluids at rest. It embraces the study of the conditions under which fluids are at rest in stableequilibrium; and is contrasted with fluid dynamics, the study of fluids in motion.
• the dynamics of fluids are the foundation of the understanding of water movement in streams and in the subsurface
• we need to understand this in order to figure out how to measure river discharge, for example
• the basic principles also apply to the flow of air, lava, glaciers, and the Earth's mantle
• we usually classify matter as either solid, liquid, or gas, based on macroscopic properties
o a gas takes on the shape and volume of a container,
o a liquid takes the shape of the portion of the container that it fills but retains a fixed volume
o a solid has its own defined shape as well as volume
• liquids and gases are called fluids
• shear stress is a tangential force per unit area acting on a surface
Police found two bodies within 16 hours of each other. The first was a woman found in her flat after music had been playing for days. Her death was not considered suspicious. The second was a man found in the woods dressed in sportswear and had clearly been there some time. Autopsies will be conducted to determine the causes of death. Forensic science uses tools like fingerprints, dental records, and DNA profiling to identify bodies and determine when and how people died. DNA profiling relies on each person having a unique DNA pattern, except for identical twins. It examines short tandem repeats at specific loci to generate DNA profiles for identification.
This experiment aimed to generate Escherichia coli resistant to bacteriophage T1 and classify mutations. Plaque assays to isolate resistant mutants were unsuccessful, yielding no plaques. Regrowth of mutants from previous research was successful, as was MRVP testing to confirm the regrown cultures were E. coli. Genomic DNA was isolated from positive mutant cultures and will undergo PCR amplification and analysis. In summary, the experiment generated no new resistant mutants but validated previous work characterizing E. coli mutations that confer resistance to bacteriophage infection.
The study characterized the Campylobacter jejuni IAL 2383 strain isolated from humans in Brazil. They found that the strain harbored important virulence genes and expressed major virulence factor transcripts. It grew better at 41°C than 37°C, indicating ability to colonize avian hosts. The strain was sensitive to most antibiotics tested and could serve as an experimental model for interactions with host cells and acquisition of antibiotic resistance.
This document describes the development of a real-time PCR assay to detect and quantify Vibrio alginolyticus using the groEL gene. A species-specific primer was designed based on alignments of groEL gene sequences. Testing showed the primer only amplified V. alginolyticus and not other Vibrio or non-Vibrio strains. The assay was sensitive enough to detect as few as 10 cells per ml and was used to quantify V. alginolyticus artificially inoculated into shellfish and shrimp samples.
The document summarizes a Quantiswab study conducted by an intern to verify the recovery of microorganisms using the Quantiswab technique. Five organisms (Aspergillus brasiliensis, Bacillus subtilis, Candia albicans, Pseudomonas aeruginosa, Staphylococcus aureus) were inoculated onto steel coupons and allowed to dry. The coupons were then swabbed using Quantiswabs and the swabs processed in different ways to quantify recovery percentages. Unfortunately, none of the recovery percentages met the target 70-130% range. The intern concluded it was a valuable learning experience but that more work is needed to optimize the Quantiswab technique for higher recovery
Since Staphylococcus nepalensis were reported for the first time from Nepalese animal specimen, and have been reported from human specimens elsewhere, this bug can be a threat in our part. Protocols must be designed aimed at their identification in our laboratory during microbiological analysis of clinical specimens.
Isolation and Identification of MDRO's in the Rio Grande River PosterKayleeWersant
Antibiotic resistant bacteria was found in water samples from the Rio Grande River. 19 out of 34 isolated bacterial samples showed resistance to at least 4 classes of antibiotics. Common antibiotic resistant bacteria isolated included E. coli and Klebsiella pneumoniae. The presence of antibiotic resistant bacteria in the river implies that antibiotic resistance is a growing issue affecting an important water source used for agriculture, recreation, and domestic purposes in Texas, Colorado, and New Mexico.
This document summarizes a study that examined soil samples from 17 bat hibernacula caves in Oklahoma for the presence of Pseudogymnoascus destructans, the fungus that causes white-nose syndrome. 83 soil samples were tested using real-time polymerase chain reaction analysis and none were found to contain genetic material from P. destructans. The study suggests that P. destructans has not yet reached Oklahoma based on these results and previous negative tests of bats in the state.
The document outlines Stephanie Roto's thesis defense presentation on her research investigating the effects of feeding Original-XPCTM on modulating the cecal microbiota and inhibiting Salmonella survival in poultry hosts. Her research included in vitro assays examining Salmonella survival when treated with XPC and in vivo feeding trials analyzing how XPC impacts the cecal microbiota and Salmonella prevalence at different ages. Her results showed that XPC treatment led to a more rapid decrease in Salmonella survival by 24 hours and did not significantly alter the cecal microbial diversity between treatments but did increase with bird maturity.
This document describes the isolation and characterization of a new giant virus called Cedratvirus. Key points:
- Cedratvirus was isolated from an environmental sample in Algeria using Acanthamoeba castellanii.
- It has an ovoid shape with a cork structure at each end, resembling Pithovirus sibericum but with a unique double cork feature.
- The 589kb genome is most closely related to the pithovirus genomes, sharing over 100 genes, but with only 21% of genes involved in best reciprocal hits, indicating genetic distance from known pithoviruses.
PREVALENCE AND ANTIMICROBIAL SUSCEPTIBILITY OF ESBL IN SOKOTO PDFNuhu Tanko
This study examined the prevalence and antimicrobial susceptibility of extended-spectrum beta-lactamase (ESBL)-producing gram-negative uropathogens in Sokoto, Nigeria. 365 urine samples were collected and analyzed between November 2014 and February 2015. Gram-negative uropathogens made up 60.9% of positive cultures. The most common isolates were E. coli (29.7%) and Salmonella arizonae (23.4%). 15 isolates (23.3%) were confirmed as ESBL producers, with E. coli and Enterobacter gergoviae being the most common. The isolates showed high resistance to cotrimoxazole but high susceptibility to nitrofurantoin. This study demonstrates
This document describes the development and validation of a new quantitative PCR (qPCR) assay to estimate total bacterial load in stool samples.
1) The assay targets a conserved region of the 16S rRNA gene using new primers and a probe to generate a shorter amplicon compatible with clinical diagnostics.
2) Testing on 500 liquid and 50 solid stool samples showed the assay accurately measured total bacterial load compared to culture-based methods.
3) The new assay addresses previous issues with non-specific priming and amplification bias, and provides a standardized method for quantifying total bacteria in complex clinical samples.
Seshu K. Gudlavalleti has over 20 years of experience in vaccine development and microbial biochemistry. He received his PhD from Jawaharlal Nehru University and has held positions at the FDA, Emory University, and currently works as Chief Scientist at JN Medical Corporation developing meningococcal conjugate vaccines. He has authored over 15 publications and holds one US patent related to his work developing vaccines and characterizing microbial proteins and polysaccharides.
Dr. Ying Fang - Emerging swine disease diagnostics and characterization: conn...John Blue
Emerging swine disease diagnostics and characterization: connecting basic research to real-world applications - Dr. Ying Fang, Kansas State University, from the 2017 North American PRRS/National Swine Improvement Federation Joint Meeting, December 1‐3, 2017, Chicago, Illinois, USA.
More presentations at http://www.swinecast.com/2017-north-american-prrs-nsif-joint-meeting
Detection and Subtype Identification of Blastocystis Isolates from Wastewater...gon0603
Presented during the 6th Asian-Pacific Organization for Cell Biology (APOCB) International Congress, EDSA Shangri-La, Manila, Philippines, 25 to 28 February 2011
The document describes a study that tested a rapid saturated phenol screening method for detecting plasmids in bacteria. Several bacterial isolates were screened for plasmids using both the alkaline lysis method and the rapid screening method. The rapid method more quickly and consistently detected plasmids in three isolates. It is a simple, efficient alternative to alkaline lysis screening for plasmid presence or absence and allows screening many samples in a short time.
Richelle SOPKO is a biologist with expertise in kinase signaling pathways. She has extensive experience using techniques like proteomics, RNAi, transgenic animals, and mass spectrometry to identify kinase targets and characterize cellular signaling. Currently a postdoctoral fellow at Harvard Medical School, her work involves mapping phosphorylation pathways in Drosophila and examining crosstalk between survival pathways in blood cells.
10 the influence of environmental bacteria in freshwater stingraypryloock
The document discusses a study on bacteria found in the mucus of freshwater stingrays (Potamotrygon motoro) and river water in Brazil, and the ability of these bacteria to cause infections. The study identified bacteria from stingray mucus and river water samples, finding mostly gram-negative bacteria like Aeromonas spp. and Enterobacter cloacae. Some bacteria produced toxins that damaged human cells in lab tests. Antibiotic testing found that 68% of bacterial isolates were resistant to at least one antibiotic. While stingray venom was toxic to cells, it did not increase bacterial growth. In summary, bacteria from stingray mucus and river water could transfer into wounds and cause severe secondary infections.
Detection of Wuchereria bancrofti DNA in paired serum and urine samples using...dewisetiyana52
This study aimed to standardize PCR-based systems for the diagnosis of lymphatic filariasis using serum and urine samples. Paired biological samples were collected from 20 individuals known to be infected with Wuchereria bancrofti. Conventional and semi-nested PCR assays were optimized to detect W. bancrofti DNA. The internal PCR system was able to detect as little as 10 fg of W. bancrofti DNA and detected infection in all 20 patients using both serum and urine samples. In contrast, the semi-nested PCR only detected infection in 2 of the 20 patients. This study demonstrates the potential of using a simple internal PCR system and urine samples for the diagnosis of W. b
1. The study analyzed 30 Vibrio cholerae O1 isolates from patients in Delhi, India from 2012-2014 using mismatch amplification mutation assay (MAMA) PCR to identify the ctxB genotype.
2. All isolates were biochemically identified as V. cholerae El Tor serotype Ogawa. MAMA PCR results showed that all isolates carried the ctxB gene of the classical biotype, though they were phenotypically El Tor.
3. This identifies an "altered El Tor" variant circulating in Delhi that displays characteristics of both classical and El Tor biotypes in possessing the classical ctxB gene despite being phenotypically El Tor.
FLUID MECHANICS
Fluid mechanics is the branch of physics which involves the study of fluids (liquids, gases, and plasmas) and the forces on them. Fluid mechanics can be divided into fluid statics, the study of fluids at rest; and fluid dynamics, the study of the effect of forces on fluid motion. It is a branch of continuum mechanics, a subject which models matter without using the information that it is made out of atoms; that is, it models matter from a macroscopic viewpoint rather than from microscopic. Fluid mechanics, especially fluid dynamics, is an active field of research with many problems that are partly or wholly unsolved. Fluid mechanics can be mathematically complex, and can best be solved by numerical methods, typically using computers. A modern discipline, calledcomputational fluid dynamics (CFD), is devoted to this approach to solving fluid mechanics problems. Particle image velocimetry, an experimental method for visualizing and analyzing fluid flow, also takes advantage of the highly visual nature of fluid flow.
The study of fluid mechanics goes back at least to the days of ancient Greece, when Archimedes investigated fluid statics and buoyancy and formulated his famous law known now as the Archimedes' principle, which was published in his work On Floating Bodies - generally considered to be the first major work on fluid mechanics. Rapid advancement in fluid mechanics began with Leonardo da Vinci (observations and experiments), Evangelista Torricelli (invented the barometer), Isaac Newton (investigated viscosity) and Blaise Pascal (researched hydrostatics, formulated Pascal's law), and was continued by Daniel Bernoulli with the introduction of mathematical fluid dynamics in Hydrodynamica .
Fluid statics or hydrostatics is the branch of fluid mechanics that studies fluids at rest. It embraces the study of the conditions under which fluids are at rest in stableequilibrium; and is contrasted with fluid dynamics, the study of fluids in motion.
• the dynamics of fluids are the foundation of the understanding of water movement in streams and in the subsurface
• we need to understand this in order to figure out how to measure river discharge, for example
• the basic principles also apply to the flow of air, lava, glaciers, and the Earth's mantle
• we usually classify matter as either solid, liquid, or gas, based on macroscopic properties
o a gas takes on the shape and volume of a container,
o a liquid takes the shape of the portion of the container that it fills but retains a fixed volume
o a solid has its own defined shape as well as volume
• liquids and gases are called fluids
• shear stress is a tangential force per unit area acting on a surface
Police found two bodies within 16 hours of each other. The first was a woman found in her flat after music had been playing for days. Her death was not considered suspicious. The second was a man found in the woods dressed in sportswear and had clearly been there some time. Autopsies will be conducted to determine the causes of death. Forensic science uses tools like fingerprints, dental records, and DNA profiling to identify bodies and determine when and how people died. DNA profiling relies on each person having a unique DNA pattern, except for identical twins. It examines short tandem repeats at specific loci to generate DNA profiles for identification.
Agarose gel electrophoresis is a technique used to separate DNA fragments by size. It involves preparing an agarose gel by dissolving agarose powder in buffer solution and pouring it into a casting tray. Samples are loaded into wells in the gel and an electric current is applied, causing DNA fragments to migrate through the agarose at rates depending on their size. After running the gel, DNA bands can be visualized by staining with ethidium bromide and exposing the gel to UV light. Agarose gel electrophoresis has applications in analyzing PCR products and restriction enzyme digests.
This PowerPoint is one small part of the Geology Topics unit from www.sciencepowerpoint.com. This unit consists of a five part 6000+ slide PowerPoint roadmap, 14 page bundled homework package, modified homework, detailed answer keys, 12 pages of unit notes for students who may require assistance, follow along worksheets, and many review games. The homework and lesson notes chronologically follow the PowerPoint slideshow. The answer keys and unit notes are great for support professionals. The activities and discussion questions in the slideshow are meaningful. The PowerPoint includes built-in instructions, visuals, and review questions. Also included are critical class notes (color coded red), project ideas, video links, and review games. This unit also includes four PowerPoint review games (110+ slides each with Answers), 38+ video links, lab handouts, activity sheets, rubrics, materials list, templates, guides, 6 PowerPoint review Game, and much more. Also included is a 190 slide first day of school PowerPoint presentation.
Areas of Focus within The Geology Topics Unit: -Plate Tectonics, Evidence for Plate Tectonics, Pangea, Energy Waves, Layers of the Earth, Heat Transfer, Types of Crust, Plate Boundaries, Hot Spots, Volcanoes, Positives and Negatives of Volcanoes, Types of Volcanoes, Parts of a Volcano, Magma, Types of Lava, Viscosity, Earthquakes, Faults, Folds, Seismograph, Richter Scale, Seismograph, Tsunami's, Rocks, Minerals, Crystals, Uses of Minerals, Types of Crystals, Physical Properties of Minerals, Rock Cycle, Common Igneous Rocks, Common Sedimentary Rocks, Common Metamorphic Rocks.
This unit aligns with the Next Generation Science Standards and with Common Core Standards for ELA and Literacy for Science and Technical Subjects. See preview for more information
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Gel electrophoresis is a technique used to separate DNA fragments by size. It works by applying an electric current to gel, causing negatively charged DNA fragments to migrate at different rates depending on their size. Smaller fragments move faster through the gel than larger ones. After running the current, DNA bands can be visualized by staining with ethidium bromide and viewing under UV light. Gel electrophoresis has various applications such as analyzing human DNA for forensics, diagnosing genetic diseases, and determining paternity.
The document defines key terms and concepts related to industrial pneumatics, including:
- The physical states of matter and how gases differ from liquids
- Common gas laws such as Boyle's law, Charles' law, and the combined gas law
- Fundamental pneumatic terms like pressure, vacuum, and compressibility
- Primary components of compressed air systems like filters, regulators, lubricators
- Types of pneumatic valves, actuators, and motors
The document describes the similarities between pneumatic and electrical systems. It explains key pneumatic components like pressure regulators, non-return valves, solenoid valves, and timers and their analogous electrical components. It then provides examples of pneumatic circuits used in container spreaders and discusses common faults that can occur.
Hydraulics and pneumatics systems are used in aircraft to transmit power and motion efficiently. Hydraulic systems use confined liquids to multiply force, while pneumatic systems use compressed air. Pascal's law states that pressure in a confined incompressible fluid transmits equally in all directions. Hydraulic systems have advantages like weight savings and unlimited force development that make them ideal for aircraft applications like flight controls. Pneumatic systems provide a reserve power source but lack the accuracy and response of hydraulics due to air compressibility.
Pneumatics is the use of compressed air to power machinery. It involves the movement of air under pressure and dates back to the 17th century when a German scientist invented the first air pump. Some key pneumatic inventions include the first air pump in 1650, the pneumatic subway in New York in 1870, and the pneumatic tire in 1888. Today, pneumatics is used in jet engines, machinery, and can be found in everyday items like tires, air brakes, and air tools.
Babic components of hydraulic & pneumatic systemswakurets_21
The document discusses the basic components and applications of hydraulic and pneumatic systems. It describes the main types of hydraulic and pneumatic actuators including linear actuators like cylinders, and rotary actuators like motors. It also explains the different types of valves used in hydraulic and pneumatic circuits including directional control valves, flow control valves, and pressure control valves. The purpose and basic operation of common valve types are provided like poppet valves, spool valves, needle valves, check valves, and relief valves.
150 WORDS AGREE OR DISAGREE1. Explain the proper collection ancargillfilberto
150 WORDS AGREE OR DISAGREE
1. Explain the proper collection and packaging methodologies for biological evidence. Why should biological evidence never be packaged in air-tight or non-breathable mediums?
The proper collection and packaging methodologies for biological evidence is important for investigators to follow in order to properly preserve evidence and not allow it to be contaminated. First, to explain what biological evidence is classified as, we will describe a few of the different specimens. Blood, saliva, or semen are common types of bodily fluids that can be retrieved at a crime scene. In order to properly contain these specimens, investigators will use a cotton swab that is encased in a plastic cover to protect the swab from being contaminated and they label where and when the located the specimen (Plaza, 2016). Fingerprints or teeth marks are other forms of biological evidence. These can be lifted using adhesives that can pull the print from the piece of evidence. If the adhesive will destroy the evidence, then the investigator will take a photograph of the dusted print and use this to examine in the lab. Teeth marks can be copied using a type of plaster that will fill the cavity left by the bite. This can be compared to dental records (Dorion, 2011).
Storing biological evidence is complicated because if you store it in air-tight container can damage the evidence by allowing it be effected by outside temperatures that can cause bacteria to grow on the evidence if not allowed to breath. Keeping the material in a dry location with a controlled temperature can preserve the evidence for a longer period of time. Not allowing the evidence to be stored properly can also cause the evidence to dry up and no longer be useful. Once DNA is damaged, it cannot be replicated or repaired (Lee, 2011).
2. What is PCR analysis? Why is this application important particularly for cold cases or cases in which only a small amount of DNA is recovered?
PCR is Polymerase Chain Reaction and is a test that replaced the Restriction Fragment Length Polymorphism test in the late 1990s (Minor, 2013). This test I able to develop a DNA sample and profile from biological evidence that was once deemed extremely small (DOJ, 2002). This test is able to do so by copying the DNA and reproducing it without causing damage to the original piece of evidence. This process is very important to cold cases because investigators have the ability to reconstruct DNA from evidence that may have previously been deemed damaged. When DNA evidence is damaged or only a small amount remains, this test can help investigators piece together the events and possibly assist in solving the cold case.
3. What is STR analysis? Why is this an effective method for DNA typing?
STR analysis is Short Tandem Repeat technology that can evaluate a specific region of DNA (DOJ, 2002). This test is able to compare DNA samples and identify the matching profile against ...
This document provides details of a study on screening, characterization, and antibiotic resistance testing of pathogens from various clinical specimens. Over 6,000 samples, including urine, blood, pus, sputum, and others, were collected and analyzed using microbiological techniques. Isolates were identified based on morphological and biochemical characteristics. Antibiotic susceptibility testing was performed using disk diffusion methods. Multiple drug-resistant organisms were detected. The study aimed to determine the prevalence and antibiotic resistance patterns of pathogens from different specimens to help guide treatment of infectious diseases.
This document summarizes a study that investigated the potential of using an individual's microbial fingerprint to link them to items they have touched. Fifteen individuals provided samples from their fingertips, personal laptops, chairs, a shared office doorknob, and photocopier. Bacterial DNA was extracted and 16S rRNA gene PCR and sequencing was used to analyze and compare the bacterial communities between samples. The results showed higher similarity between individuals' fingerprints and personal items than shared surfaces. Some individuals like regular users of the doorknob showed closer links between their fingerprints and the doorknob. Therefore, an individual's unique bacterial profile on their skin and possessions could potentially be used as a forensic tool to associate them with touched objects.
Evaluation of subgingival bacteria in the dog and susceptibility to commonly ...Daniel Ferro
Resistência bacteriana: o uso indiscriminado de antimicrobianos indicados para tratamento de afecções orais tem sido discutido como fonte importante de resistência bacteriana.
Este estudo apresenta cepas resistentes e discute novas formas de aplicação dos medicamentos.
This document summarizes a student's research project that sampled 12 surfaces in men's and women's bathroom daily over a week to quantify microbes present. The student plated samples on two types of media and counted colony forming units. The results showed the men's bathroom had more growth than women's, though not significantly. Tuesday had significantly more growth than Friday. The paper towel dispenser had the most growth of all surfaces sampled. Though some differences were found, the student notes limitations and that not all bacteria collected may be harmful.
Genetic engineering involves modifying an organism's genes using technology. It was first achieved in 1973 when Herbert Boyer and Stanley Cohen inserted antibiotic resistance genes into bacterial DNA. Rudolf Jaenisch then created the first genetically modified animal, a mouse, in 1974. In 1994, the first genetically modified food, a longer-lasting tomato, was approved for sale. More recently, scientists have developed new gene editing tools like CRISPR that allow more precise genetic modifications. While genetic engineering enables benefits like increased food production and disease resistance, it also raises concerns about unintended health and environmental impacts.
1. This laboratory focused on practicing proper micropipetting techniques. Students mixed solutions of water and dyes to practice using micropipettes accurately and safely. This helped prepare them for upcoming labs requiring precise measurements.
2. Students learned different microscopy techniques, including fluorescence and bright field microscopy. They took photomicrographs using a camera attached to the microscope.
3. Over three days, students extracted their own DNA from mouth cells, ran PCR tests to determine if a patient sample had diabetes, and used gel electrophoresis to analyze protein biomarkers and diagnose a lysosomal storage disorder.
The document discusses Streptococcus pyogenes, a common bacterial pathogen in humans. It causes diseases like strep throat, scarlet fever, and puerperal fever. S. pyogenes is Gram-positive and spherical, often appearing in chain-like formations under a microscope. It is sensitive to penicillin. The author describes experiments identifying an unknown bacteria as S. pyogenes based on tests showing Gram-positive cocci, negative catalase, beta hemolysis on blood agar, and inconsistent growth on selective media. The document reviews several studies on S. pyogenes strains isolated from children with pharyngitis.
Characterization of Bacteria Isolated from Tropical Soils of Puerto Rico ramoncolon7
This document summarizes a student research project that aimed to characterize bacteria isolated from soils in Puerto Rico. Soil samples were collected and bacteria were isolated on agar plates before being purified through restreaking. Gram staining identified the bacteria as either gram-positive or gram-negative. Genomic DNA was extracted and amplified via PCR. However, when tested on indicator plates, the isolated bacteria did not show any antibiotic production against E. coli or M. luteus as hypothesized. While full characterization was not completed due to time constraints, the student plans future work identifying the bacteria through DNA sequencing.
The document describes an experiment conducted by Lizbeth Pérez Castro and Javier Zavala Ayala to isolate a novel bacteriophage from soil samples collected in Puerto Rico. Soil samples were collected and enriched with bacterial hosts, then filtered and purified through multiple rounds of plating and streaking. A novel mycobacteriophage was successfully isolated from a soil sample collected near cow feces. The isolated phage, termed Nitidusvenutus, was then characterized through proteomic analysis, electron microscopy, and genomic DNA extraction and analysis.
Objective: To evaluate the antibacterial effects of 4 different cavity disinfectants on Streptococcus mutans, Lactobacillus acidophilus, and Enterococcus faecalis bacteria in different time periods.
Study Design: The antibacterial effects of Cavity Cleanser, Tubulicid Red Label, Chloraxid 2%, and Oxygenated Water cavity disinfectant solutions on E. faecalis (ATCC 29212), S. mutans (ATCC 25175), and L. acidophilus (RSKK 03037) bacterial strains were evaluated by disk diffusion method. In the study where vancomycin antibiogram disc constituted the positive control group, physiological saline solution was used as the negative control group. Standard, sterile, blank antibiogram discs of 5 mm in diameter, in which 15 μL of each material were added, were placed on agar plates at 2.5–3 cm intervals. The inhibition zone diameters formed around the discs that were left to incubate for 24–48 hours at 37°C were measured in millimeters. Statistical analysis of the data was performed using one-way analysis of variance, Kolmogorov-Smirnov, Levene, and Bonferroni tests.
Results: At the end of the study the solutions tested showed a statistically significant antibacterial effect on all bacterial strains used (p<0.05). Cavity Cleanser disinfectant containing 2% chlorhexidine showed the highest antibacterial effect on S. mutans and L. acidophilus, and benzalkonium-containing Tubulicid Red disinfectant on E. faecalis.
Conclusion: The antibacterial effect of all cavity disinfectants used in the study was found to be higher at the end of the 48th hour than at the end of the 24th hour, but there was no statistically significant difference (p>0.05).
Keywords: antibacterial agents; antibacterial effect; cavity disinfectants; chlorhexidine; contamination; dental caries; disinfection; disc diffusion; gram-negative bacteria; gram-positive bacteria
This research aimed to characterize bacteria isolated from soils in Puerto Rico. Two soil samples were collected and various tests were performed on the isolated bacteria, including Gram staining, DNA purification and amplification, and testing for antibiotic production. One isolated bacterium (S15UPRC-RISEAMGP30SP01A1) was identified as a gram-positive cocci resembling Staphylococcus and did not produce antibiotics. The other (S15UPRC-RISERBCR30P01A2) was a gram-positive Bacillus but did not produce antibiotics. Neither bacterium could be fully characterized due to negative PCR results, failing to confirm the hypothesis of positive antibiotic production. Further tests are needed to fully characterize the
Evolution of dental informatics as a major researchGaurav Salunkhe
This document discusses the evolution of dental informatics as a major research tool in oral pathology. It describes how dental informatics incorporates knowledge from various fields like health science, computer science, and information technology. The primary goals are to increase understanding of biological processes and improve patient outcomes. Major areas of research include gene finding, genome assembly, protein structure prediction, and drug design. Applications discussed include using microarrays and genomics/proteomics for early oral cancer detection, identifying genetic factors that influence disease progression, and cataloging proteins in oral fluids. The conclusion states that combining experimental and theoretical approaches from various disciplines like bioinformatics will provide better understanding of oral diseases at the molecular level.
The document describes a lab experiment that tests how the addition of a pGLO plasmid affects the growth and characteristics of E. coli bacteria. The experiment involves transforming E. coli bacteria with the pGLO plasmid by adding it to a solution containing the bacteria. One solution receives the pGLO plasmid (+pGLO) while the other does not (-pGLO). The bacteria are then observed under UV light and incubated under various conditions to analyze effects on growth and gene expression.
This document provides an overview of animal models used in periodontal research. It discusses the definition and history of animal models, the need for animal models in periodontal research given limitations of human studies, and various categories and classifications of animal models. The document then examines specific animal models used in periodontal research, including rats, mice, and hamsters, describing their anatomy, how periodontal disease presents in each, and advantages and limitations of each model.
Medical biotechnology uses living cells and organisms to develop medical products and therapies. It has applications in areas like stem cell research, the Human Genome Project, recombinant DNA technology, gene therapy, vaccine development, insulin production, diagnostics, and genetic engineering. Some key contributions of medical biotechnology include completing the human genome sequence, producing the first genetically engineered human insulin to treat diabetes, and developing vaccines that have saved millions of lives.
Abstract
An examination experiment has been carried out to investigate whether fingerprint powder and lifting technique can recover and transfer latent fingerprints from human skin surfaces of dead bodies. For recovery Swedish Black powder and for transfer White Fingerprint Gelatine were used.
Donors placed fingerprints on the human skin surfaces. Finger marks were then in all cases recovered with Swedish Black powder. The procedure was repeated after 2, 3, 4 and 5 hours. Treated finger marks were secured and preserved as latent fingerprint evidence by lifting process. We recovered 8% finger marks suitable for further examination of all deposited samples on the human skin surfaces.
Wagner College Forum for Undergraduate Research, Vol. 15 No. 1Wagner College
This document provides an introduction and summaries of papers presented in the Wagner Forum for Undergraduate Research journal. It discusses the purpose of the journal in publishing student research and outlines the sections and types of papers included. Abstracts are provided for 10 studies presented at the Eastern Colleges Science Conference on topics ranging from bacterial infections in zebrafish to the effects of plant extracts on bacteria. Full papers are summarized on detecting proteins in flatworm genomes and the benefits of diversity in corporate management.
Wagner College Forum for Undergraduate Research, Vol. 15 No. 1
final senior research paper
1. Matching Bite Mark Bacterial DNA to the Mouth of the Biter and Matching Dental
Impressions to Bite Marks Left on the Body
Brittany Cottingham
Abstract
The goal of this study was to investigate the possibility of matching oral bacterial DNA
from a fresh human bite mark to the oral bacterial DNA of the biter. When little to no evidence is
left at a crime scene, this protocol could provide a new insight into crime scene investigation. In
this experiment, bacterial samples were collected from 5 volunteers. They were instructed to bite
their biceps and the bite marks were then swabbed after the bite, after an hour had passed, and
again 12 hours later. All swabs were plated, then bacterial DNA was extracted from each sample
and PCR was run using primers designed to identify the bacterial species. The bacteria were not
conclusively identified, so the mouth band bite mark bacterial DNA could not be conclusively
matched. Each participant also had dental impressions made, which were used to compare and
match each volunteer’s impression to the picture of their bite mark. Out of the five dental
impressions, only one was able to be matched correctly. This study provides evidence that with
more time, microbial analysis of bite marks may be a promising tool used in forensics.
Introduction
Assault cases are being dismissed if there is little to no human DNA or if the victim
cannot identify their attacker (FBI, 2010). Cases in which bite marks are present can yield
desirable results in catching the perpetrator. One of the most famous cases in history that used
bite mark evidence was the Ted Bundy case. A main component in this conviction was the
examination and analysis of a bite mark he left on one of his victims. The odontologist for the
2. case was able to match his dental records to a photo of the bite marks found on the victim
(Bundy vs. State 1984).
Although bite mark analysis can be a useful tool, problems can occur when a bite mark is
left on a body. One of the major problems that can occur is that the bite mark can be distorted by
the movement of the dentition, but also because the skin is a poor material used for impressions
(Rothwell 1995). There are a set of characteristics that forensic odontologists consider when
examining bite marks. These characteristics include the presence or absence of each tooth, shape
of the teeth, and any abnormalities, such as fractured teeth (Glass et al 1980). The problem is that
any distortions in the bite mark, such as sliding the teeth down the skin, can mask any of the
characteristics, allowing for a false ID. Bite mark distortion is common, so to prevent a wrong
conviction, oral bacterial DNA may be used as evidence in cases which are otherwise thought to
have no evidence. The enzymes in saliva take longer to deteriorate the bacteria left behind
because it takes longer to digest the cell wall (Rahimi, et al 2005). Human DNA lacks a cell wall,
so the enzymes found in saliva deteriorate the DNA much quicker. By collecting the oral bacteria
left behind on a bite mark and amplifying their bacterial DNA by means of Polymerase Chain
Reaction, it can be compared to oral bacteria from the mouth, and used as evidence (Rahimi, et al
2005).
Though oral bacteria’s greatest use will be in aiding in the identification of a suspect, it
can also be helpful in determining the age of the bite mark. There isn’t a specific amount of time
known for how long oral bacteria can survive on the skin before it is either outcompeted or the
saliva degrades the cell wall, but the amount of bacteria collected from the skin can give
scientists a better understanding of the bacterial survival rate. This is important to determine
because most women who have been assaulted won’t report it for up to 12 hours after the attack,
3. on average (Peipert and Domagalski 1994). In this experiment, very little bacteria were found
after 12 hours, however, one study (Rahimi et al 2005) had a group of participants bite
themselves, and then waited 24 hours to gather the bacteria. Their results showed that even after
24 hours had past, oral bacteria from the biter were still able to be gathered from the marks. As
stated in similar studies, Streptococcus is the most prevalent genus found in the human mouth
(Rahimi 2005). Using this information, both Rahimi et al. (2005) and Kennedy (2011) swabbed
the bacteria that was collected from bite marks on a plate and allowed it to grow. Without
identifying the genus of the bacteria, they proceeded to perform PCR to amplify the bacterial
DNA. Next they ran gel electrophoresis, which showed the DNA profile needed to match the
samples. By comparing the bacteria from the mouths of the participants to the unknown bite
mark, they were able to correctly match the bacterial DNA from the unknown bite mark to the
bacterial DNA from the mouth of the biter (Rahimi et al. 2005)).
In order for PCR to be successful, primers are required. Primers act as starting points in
the amplification of bacterial DNA, which is then visualized through the bands that appear
during gel electophoresis. In an experiment performed by Chen et al. (2007), the primers
Sm479F and Sm479R were used. This primer pair is typically species specific for Streptococcus
mutans. S. mutans is the major bacteria species found in oral cavities. The purpose of Chen’s
(2007) experiment was to research S. mutans effect on dental caries and used the primer pair to
identify the bacteria. Using the primer pair Sm479F/R, Chen (2007) was able to show that the
primer pair was species specicific to S. mutans by identifying the species from a mixed sample.
Using this as a reference, bacteria was collected from the mouths of five volunteers and
from their bite marks after they were directed to bite themselves, one hour after, and 12 hours
afterward. DNA was extracted using a protocol specific for Streptococcal species. PCR was used
4. to amplify specific regions of Streptococcus mutans DNA and the DNA was then ran using gel
electrophoresis. No PCR products appeared, though DNA was clearly present in the gel. If more
time were allowed, the bacteria would have been identified and S. mutans would have been
specifically isolated. The primer pair Sm479F/R would have been used to identify S. mutans and
another primer would have been used to amplify the bacterial DNA and the bands would have
made a DNA profile that could have be used to match the DNA from the bite mark to the mouth.
When comparing the dental impressions to the bite marks, looking for the aforementioned
characteristics, distortions in the bite marks caused problems in matching the impressions to the
bite mark in all but one case. Overall, a new and an old method were attempted to match a bite
mark to the biter.
Materials and Methods
Before beginning the experiment, an IRB form was submitted, explaining the use of the
human subjects and the task they had to accomplish. It took about two months to get approved
and the experiment was allowed to begin. A blind study was performed using five volunteers.
Each volunteer signed a consent form stating that they understood any dangers involved in
participating in this study. For the purpose of the experiment, each volunteer bit themselves on
the bicep hard enough to leave an impression that lasted roughly 10 minutes. The section of the
bicep that was bitten was degermed with an alcohol wipe prior to biting so the bacteria collected
were strictly from the mouth. Photos of the bite mark were taken for comparison purposes. The
incisors and canines, the teeth that most prominently leave marks on the skin, were swabbed with
a sterile cotton swab, along with the saliva, for bacteria. The participants’ skin was swabbed after
the bite, one hour after the bite, and again 12 hours after the bite occurred with a sterile cotton
swab.
5. After all of the samples had been collected, the assistant randomly assigned each piece of
evidence a number, 1-5, each bite mark photo a number, 6-10, and each swab from mouth and
teeth, 21-40. The code was unknown to the experimenter.
Each of the collected samples was swabbed onto Nutrient Agar (Carolina, Burlington, NC)
and the plates were placed in an incubator for 48 hours at 37°C. After the 48 hours, the different
types of bacterial colonies grown were counted and gram stained to determine whether the
colony was gram positive or negative. Every colony was then grown in its own tube of nutrient
broth, which was also incubated for 48 hours at 37°C. After the 48 hours, a sample total of 5mL
of bacteria was taken from the tubes originating from the same plate and were mixed together,
combining all bacterial species (for example, plate 7 had five bacterial samples growing on it.
1mL was taken from each of the five tubes to make a total of 5mL of bacteria from plate 7). All
plates and tubes were placed at 4°C for storage.
Bacterial DNA Extraction
Sigma GenElute Bacterial Genomic DNA Kit (St. Louis, MO) was used to extract
bacterial DNA with the addition of Lysozyme from chicken egg white. A lysozyme solution was
made by diluting 2,115,000U/mL of lysozyme in 10mL of Gram-Positive Lysis Solution, making
a lysozyme solution stock of 4200µL. In order to extract the bacterial DNA, 1.5mL of bacterial
broth was pelleted by centrifuging for 2 minutes. The pellet was then resuspended by adding
200µL of Lysozyme Solution and then incubated at 37°C for 30 minutes. After 30 minutes, 20µL
of Proteinase K solution was added to the suspension, followed by 200µL of Lysis Solution C.
The sample was vortexed for 15 seconds and then incubated at 55°C for 10 minutes. This created
a lysate and was done for all 20 tubes. After 10 minutes of incubation, 500µL of Column
Preparation Solution was added to each binding column assembled within each tube. Each tube
6. containing this solution was centrifuged for 1 minute. 200µL were then added to the lysate and
vortexed for 10 seconds. All the contents in the tube were transferred into a clean binding
column tube, centrifuged for 1 minute at 12,000 X g, and the binding column was placed in a
new tube. 500µL of Wash Solution 1 was added to the column, centrifuged for 1 minute at 6500
X g, and the binding column was placed in a new tube. 500µL of Wash Solution was then added
to the tube, centrifuged for 3 minutes at maximum speed, and then placed in a new tube. 200µL
of Elution Buffer was added to the center of the column and centrifuged for 1 minute at
maximum speed in order to elute the bacterial DNA and the extraction was complete. This
protocol was specific for Streptococcus, which is why the primers used were for S. mutans. To
determine the amount of bacterial DNA extracted from each sample, 5µL of bacterial DNA and
45µL of water was measured using the spectrophotometer (BioRad, Hercules, CA).
Polymerase Chain Reaction
The primer pair Sm479F: 5` TCGCGAAAAAGATAAACAAACA-3`and Sm479R: 5`
GCCCCTTCACAGTTGGTTAG-3` were used. Sm479F/R is species specific for Streptococcus
mutans, meaning bands will only be produced if S. mutans is present in the bite mark.. S. mutans
is the major pathogen found in the oral cavity and the primers amplify specific regions in the 16S
rRNA genes, which are unique in S. mutans compared to other species of Streptococcus (Chen et
al 2007). In a 2mL tube, 10µL of DNA, 1µL Mg (25mM), 1µL Sm479F (10pmol/µL), 1µL
Sm479R (10pmol/µL), 0.6µL dNTP (10mM each), and 2.5µL 1X buffer were all added together.
This was done for all 20 tubes of extracted bacterial DNA. In an icycler (Bio-Rad, Hercules,CA),
the PCR was performed as follows: 95°C for 2 minutes, then 0.2µL Taq was added to each tube;
it was then followed by 40 cycles of 95°C for 30 seconds, 60°C for 30 seconds,72°C for 1
minute, and then 5 minutes at 72°C. The PCR amplified bacterial DNA was then placed in a 1%
7. agarose gel in TBE buffer and stained with 4µL of ethidium bromide (0.5µg/mL). All the
samples taken from the mouth and saliva were placed on one gel, swabs taken directly after the
bite were placed on a separate gel, swabs taken 1 hour after the bite were placed on a separate
gel, and swabs taken 12 hours after the bite were placed on a separate gel, creating a total of 4
gels. The gels were ran at 200 volts for 5 minutes, then reduced to 90 volts for 45 minutes. PCR
was ran 3 times previous to the final end products. The gel photos were documented by digital
camera.
Dental Impressions
All 5 volunteers were taken to Dr. Todd at C Clark Todd Dental Office in Canton, MO.
The volunteers were fitted for a metal maxillary impression plate. Putty, provided by the dentist,
was mixed and poured into the plate. The plate was placed in the mouth of the volunteer and
pushed against their top teeth until the putty hardened. This was repeated with the bottom set of
teeth and for each volunteer. Once all molds were made, they were left to dry for 30 minutes.
After 30 minutes, a plaster was poured into the molds to create a stronger mold of the teeth sets.
The new molds were left to dry for 30 minutes. The molds were used as a comparison to the bite
mark photos.
Results
The volunteers were asked to bite their bicep in order to collect bacterial samples. The
bite marks were swabbed directly after the bite, 1 hour after the bite, and 12 hours after the bite.
Photographs were taken (figure 1).
8. A. B. C.
D. E.
The bacteria from the bite marks were plated and incubated. Figure 2 shows the average
bacterial samples. On average, 3 colonies were found on each plate. They ranged from white to
yellow in color and the morphology was mostly coccus with few spirillum. As clearly depicted in
figure 2, the amount of bacteria found on the skin decreases as the time increases, with the plate
almost completely covered in the initial swab of the bitemark to very colonies found after 12
hours. The different colonies found were gram stained to determine whether the bacteria were
gram-positive or gram-negative. The results from the gram stain are shown in Table 1. The
results are 7 out of 40 colonies were gram-negative and 2 out of 40 were spirillum in shape.
Streptococcus is typically gram-positive and cocci in shape, which gives the possibility that the
majority of the bacteria found were species of Streptococcus, which is what this experiment was
specific for.
Figure 1. A-E are photographs of the bite marks on the five volunteers. Each was swabbed for bacteria at 3
time intervals.
9. A. B. C.
D.
Plate the colony was found on
and letter representing it
Gram-positive or Gram-
negative
Shape
Initial Bite Mark:
1A Gram positive Coccus
1B Gram positive Coccus
2A Gram positive Coccus
2B Gram positive Coccus
4A Gram positive Coccus
4B Gram negative Coccus
4C Gram positive Coccus
11 Gram positive Coccus
16A Gram negative Coccus
Figure 2. 1A represents the average plate of bacteria swabbed from the mouth. 1B is the average of bacteria
swabbed from the initial bitemark. 1C is the average of bacteria swabbed from the bitemark after 1 hour. 1D
is the average of bacteria swabbed from the bitemark after 12 hours.
11. Mouth:
17A Gram positive Coccus
17B Gram positive Coccus
18A Gram positive Coccus
18B Gram positive Coccus
19A Gram negative Coccus
19B Gram positive Coccus
20A Gram positive Coccus
20B Gram positive Coccus
22A Gram positive Coccus
22B Gram positive Coccus
Bacterial DNA Extraction
The bacterial DNA was extracted following the Streptococcus specific protocol from the
Sigma GenElute Bacterial Genomic DNA kit (St. Louis, MO). Once the bacterial DNA from
each plate was extracted, it was analyzed with the spectrophotometer to quantify the isolated
DNA. There was no correlation between a large quantity of DNA read by the machine and the
presence of bands on the gel. The most DNA in a sample was 1981.9/µL and the least amount in
a sample was 4.2775ng/µL
Tube number Machine reading (ng/mL) Actual amount (ng/µL)
1 2.4717 61.7925
2 1.0325 25.8125
Table 1. Gram stain results for the bacteria colonies found on the plates and bacterium
morphology.
13. A. B.
C. D.
The Polymerase Chain Reaction was performed 3 times previous to the last. In the first 3
attempts, no bacterial DNA was amplified. In the last trial, all bacterial reserves were used,
which was a larger amount of DNA used previously. Figure 3A was from the initial bite mark
swab. The size of the band in the figure was greater than 10kb, which is too large to be specific
fragments of bacterial DNA. The bands were genomic DNA, which means that DNA was
isolated and that there was a large quantity, but the PCR did not work. No PCR products were
collected in this experiment.
Dental Impressions
Figure 3. Gels resulting from gel electrophoresis. A is from the initial swab of the bitemark. B is
the swab after an hour. C is the swab after 12 hours. D is the swab from the mouth.
14. A. B.
C. D.
E.
The dental impressions were matched to the bite marks based on characteristics in the dentition.
These characteristics include the shape of the teeth, the presence or absence of teeth, and any
abnormalities. Based on these characteristics, only one set was able to be matched with the
bitemark. The bottom half of the bitemark shown in Figure 5D was made by the upper teeth (Fig.
Figure 4. A-E are the dental impressions from each volunteer had made.
15. 5C). The curvature of the two front teeth on the impression matches the curvature in the
bitemark. It can also be matched by the unique structure on the bottom row of teeth. One tooth
on the bottom set is set further back than the other teeth, which is clearly shown in the figure.
The rest of the bite marks were too distorted to correctly match.
A. B.
C. D.
Conclusion
Overall, this project attempted to compare two methods to match a biter to their bite
mark. Multiple methods can be useful for future forensic studies and to have more accurate
results in crime cases.
Figure 5. Matching the bitemark to the dental impressions.
16. In previous research, Rahimi (2005) yielded positive results, with 100% matching, when
matching the bacterial DNA from a bite mark to the mouth of the biter during the experiment.
The primer pairs used in that experiment was the OPA 02 and OPA13 pair. In terms of this
experiment, the results weren’t as adequate. The primer used was Sm479F/R. This primer is said
to be species specific for Streptococcus mutans. When tested in a study, 10 S. mutans strains and
10 non-S. mutans strains were tested and only S. mutans strains were amplified (Chen et al
2007). However, it was unknown during this experiment that Sm479F/R was a primer pair used
to identify a specific bacterial species (S. mutans) and another primer pair was used to actually
amplify the bacterial DNA. When gel electrophoresis was performed, the gel didn’t produce
bands because no PCR product was produced. The band shown was genomic DNA, meaning that
bacterial DNA was extracted; however, it wasn’t amplified in a specific region. Without detailed
results from PCR and gel electrophoresis, the bacterial DNA from each source was unable to be
linked back to the person it originated from.
The second aim of this experiment was to match dental impressions of each volunteer to
the bite mark photos. With today’s technology and training, forensic odontologists are able to
correctly match teeth to bite marks, though no actual percentage has been calculated (Pretty and
Sweet 2001). In order to successfully match them, odontologists look for unique teeth markers,
use dental records, x- rays, and any other tool they deem beneficial. The bite marks obtained
during this experiment were too distorted to match, except for one bite mark, which was able to
be match to the impression because of a notable tooth variation.
For future research, it would be beneficial to determine the various species of bacteria
grown on the agar plates. This would give the researcher a specific bacterium to run PCR and gel
electrophoresis on, leading to the possible correct identification of the biter. It would also narrow
17. down the best primer to use in order to amplify the bacterial DNA. In order to match the
impressions, better photos would be needed, along with more training in the field of odontology.
With a more in depth protocol, the research on this topic may prove beneficial in its purposes.
This protocol would open a new door in forensics in terms of solving cases with no DNA other
than bacterial DNA found in saliva. It would also be beneficial because there are few ethical
issues that could be brought up, mainly because it is only bacterial DNA being used, not human
DNA.
Acknowledgments
I would like to thank all my volunteers for donating their time, Dr. LaFerriere for going
over every little thing throughout the whole process and for making sure everything was on
track, all the other science faculty at Culver-Stockton College, Laken Workman for assisting this
experiment, Michelle Hall for helping when needed, and Dr. Todd for donating all the dental
equipment needed.
References
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