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Reverse Transcription: The biosynthesis of DNA carried out on a template of RNA.

RNA Analysis of Environmental Samples Using RT-PCR

JoVE 10104

Source: Laboratories of Dr. Ian Pepper and Dr. Charles Gerba - Arizona University
Demonstrating Author: Bradley Schmitz

Reverse transcription-polymerase chain reaction (RT-PCR) involves the same process as conventional PCR — cycling temperature to amplify nucleic acids. However, while conventional PCR only amplifies deoxyribonucleic acids (DNA), RT-PCR enables the amplification of ribonucleic acids (RNA) through the formation of complementary DNA (cDNA). This enables RNA-based organisms found within the environment to be analyzed utilizing methods and technologies that are designed for DNA. Many viruses found in the environment use RNA as their genetic material. Several RNA-based viral pathogens, such as Norovirus, and indicator organisms, such as pepper mild mottle virus (PMMoV), do not have culture-based detection methods for quantification. In order to detect for the presence of these RNA viruses in environmental samples from soil, water, agriculture, etc., molecular assays rely on RT-PCR to convert RNA into DNA. Without RT-PCR, microbiologists would not be able to assay and research numerous RNA-based viruses that pose risks to human and environmental health. RT-PCR can also be employed as a tool to measure microbial activity in the env


 Environmental Microbiology

An Overview of Gene Expression

JoVE 5546

Gene expression is the complex process where a cell uses its genetic information to make functional products. This process is regulated at multiple stages, and any misregulation could lead to diseases such as cancer.

This video highlights important historical discoveries relating to gene expression, including the understanding of how distinct combinations of DNA bases encode the amino acids that make up proteins. Key questions in the field of gene expression research are explored, followed by a discussion of several techniques used to measure gene expression and investigate its regulation. Finally, we look at how scientists are currently using these techniques to study gene expression.


 Genetics

Quantifying Environmental Microorganisms and Viruses Using qPCR

JoVE 10186

Source: Laboratories of Dr. Ian Pepper and Dr. Charles Gerba - Arizona University
Demonstrating Author: Bradley Schmitz

Quantitative polymerase chain reaction (qPCR), also known as real-time PCR, is a widely-used molecular technique for enumerating microorganisms in the environment. Prior to this approach, quantifying microorganisms was limited largely to classical culture-based techniques. However, the culturing of microbes from environmental samples can be particularly challenging, and it is generally held that as few as 1 to 10% of the microorganisms present within environmental samples are detectable using these techniques. The advent of qPCR in environmental microbiology research has therefore advanced the field greatly by allowing for more accurate determination of concentrations of microorganisms such as disease-causing pathogens in environmental samples. However, an important limitation of qPCR as an applied microbiological technique is that living, viable populations cannot be differentiated from inactive or non-living populations. This video demonstrates the use of qPCR to detect pepper mild mottle virus from an environmental water sample.


 Environmental Microbiology

Prediction and Validation of Gene Regulatory Elements Activated During Retinoic Acid Induced Embryonic Stem Cell Differentiation

1Sanford-Burnham-Prebys Medical Discovery Institute at Lake Nona, 2Department of Biochemistry and Molecular Biology, Research Center for Molecular Medicine, Medical and Health Science Center, University of Debrecen, 3MTA-DE “Lendulet” Immunogenomics Research Group, University of Debrecen

JoVE 53978


 Developmental Biology

iCLIP - Transcriptome-wide Mapping of Protein-RNA Interactions with Individual Nucleotide Resolution

1Laboratory of Molecular Biology, Medical Research Council - MRC, 2European Bioinformatics Institute, EMBL Heidelberg, 3Computer and Information Science, University of Ljubljana, 4Wellcome Trust Genome Campus, Wellcome Trust Sanger Institute

JoVE 2638


 Biology

High Throughput MicroRNA Profiling: Optimized Multiplex qRT-PCR at Nanoliter Scale on the Fluidigm Dynamic ArrayTM IFCs

1The Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California San Francisco, 2Center for Reproductive Sciences, University of California San Francisco, 3Department of Urology, University of California San Francisco, 4Department of Cell and Tissue Biology, University of California San Francisco, 5Fluidigm Corporation, Fluidigm Corporation, 6Department of Obstetrics and Gynecology, Hadassah-Hebrew University Medical Center, 7UCSF - Helen Diller Family Comprehensive Cancer Center, University of California San Francisco

JoVE 2552


 Bioengineering

Streamlined Single Cell TCR Isolation and Generation of Retroviral Vectors for In Vitro and In Vivo Expression of Human TCRs

1Department of Pediatrics, Section of Diabetes and Endocrinology, McNair Medical Institute, Baylor College of Medicine, Texas Children's Hospital, 2Benaroya Research Institute at Virginia Mason, 3Center for Human Immunobiology, Baylor College of Medicine, Texas Children's Hospital, 4Department of Pediatrics, Section of Diabetes and Endocrinology, Baylor College of Medicine, Texas Children's Hospital

JoVE 55379


 Immunology and Infection

An Affordable HIV-1 Drug Resistance Monitoring Method for Resource Limited Settings

1Africa Centre for Health and Population Studies, College of Health Sciences, University of KwaZulu-Natal, Durban, South Africa, 2Unit D11, Jembi Health Systems, 3Academic Medical Center, Department of Global Health, Amsterdam Institute for Global Health and Development (AIGHD), University of Amsterdam, 4Division of Infectious Diseases and Geographic Medicine, Centre for AIDS Research, Stanford Medical School

JoVE 51242


 Medicine

Induction of Mesenchymal-Epithelial Transitions in Sarcoma Cells

1Department of Medicine, Duke University, 2Department of Bioengineering, Rice University, 3Department of Molecular Genetics and Microbiology, Duke University, 4Solid Tumor Program and the Duke Prostate Center, Duke University Medical Center, 5Duke University Medical Center

JoVE 55520


 Developmental Biology

Detecting Environmental Microorganisms with the Polymerase Chain Reaction and Gel Electrophoresis

JoVE 10081

Source: Laboratories of Dr. Ian Pepper and Dr. Charles Gerba - Arizona University
Demonstrating Author: Bradley Schmitz

Polymerase chain reaction (PCR) is a technique used to detect microorganisms that are present in soil, water, and atmospheric environments. By amplifying specific sections of DNA, PCR can facilitate the detection and identification of target microorganisms down to the species, strain, and serovar/pathovar level. The technique can also be utilized to characterize entire communities of microorganisms in samples. The culturing of microorganisms in the laboratory using specialized growth media is a long-established technique and remains in use for the detection of microorganisms in environmental samples. Many microbes in the natural environment, while alive, maintain low levels of metabolic activity and/or doubling times and are thus referred to as viable but non-culturable (VBNC) organisms. The use of culture-based techniques alone cannot detect these microbes and, therefore, does not provide a thorough assessment of microbial populations in samples. The use of PCR allows for the detection of culturable microbes, VBNC organisms, and those that are no longer alive or active, as the amplification of genetic sequences does not generally require the pre-enrichment of microorga


 Environmental Microbiology

Retrospective MicroRNA Sequencing: Complementary DNA Library Preparation Protocol Using Formalin-fixed Paraffin-embedded RNA Specimens

1Department of Research, Hackensack University Medical Center, 2Department of Medical Sciences, Seton Hall University, 3Department of Epidemiology and Population Health, Albert Einstein College of Medicine, 4Department of Nephrology and Hypertension, Hadassah - Hebrew University Medical Center

JoVE 57471


 Genetics

Glass Wool Filters for Concentrating Waterborne Viruses and Agricultural Zoonotic Pathogens

1Wisconsin Water Science Center, United States Geological Survey, 2University of Wisconsin – Madison, 3Agricultural Research Service, United States Department of Agriculture, 4Alaska Science Center, United States Geological Survey

JoVE 3930


 Immunology and Infection

Gene Expression Analysis of Endothelial Cells Exposed to Shear Stress Using Multiple Parallel-plate Flow Chambers

1Institute of Medical Science, University of Toronto, 2Keenan Research Centre in the Li Ka Shing Knowledge Institute, St. Michael's Hospital, 3Department of Laboratory Medicine and Pathobiology, University of Toronto, 4Department of Medicine, University of Toronto

JoVE 58478


 Bioengineering

CRISPR-Mediated Reorganization of Chromatin Loop Structure

1Department of Dermatology, Program in Epithelial Biology, Stanford University School of Medicine, 2Program in Cancer Biology, Stanford University School of Medicine, 3Canary Center for Cancer Early Detection, Department of Radiology, Stanford University School of Medicine, 4Department of Biology, Bridgewater State University, 5System Biosciences, 6Veterans Affairs Healthcare System

JoVE 57457


 Genetics

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