Here are some highlights from the February 2012 Issue of Journal of Visualized Experiments (JoVE).
An integrated microfluidic thermoplastic chip has been developed for use as a molecular diagnostic. The chip performs nucleic acid extraction, reverse transcriptase, and PCR. Methods for fabricating and running the chip are described.
1Agriculture and Agri-Food Canada, Lethbridge Research Centre, 2Department of Bioscience and Biotechnology, Dalian University of Technology, 3Agriculture Centre, Alberta Agriculture and Rural Development
Using readily available materials, this biocontained composting system enables effective on-site disposal of large animal carcasses arising in the event of infectious disease outbreak. This procedure kills most infectious agents in carcasses and contaminated manure. Once infectious agent is confirmed non-viable, mature compost can be spread as fertilizer.
This article describes the procedures for conducting a basic postmortem examination of a mouse or rat, and the collection of basic organs, as well as more challenging sample types from for histological, microbiological, and PCR evaluation.
A suite of spatiotemporal processing methods are presented to analyze human trajectory data, such as that collected using a GPS device, for the purpose of modeling pedestrian space-time activities.
The sialidase assay is a simple technical approach that will elucidate novel molecular mechanism(s) of TLR sensors of microbial infections and involvement in inflammatory diseases at the receptor level on the cell surface of live macrophages.
This paper describes a novel method for oral infection of mice using Listeria monocytogenes-contaminated food. The protocol can readily be adapted for use with other food borne bacterial pathogens.
Use of Fluorescent Immuno-Chemistry for the detection of Edwardsiella ictaluri in channel catfish (I. punctatus) samples
Here we describe a procedure allowing the labeling of Edwardsiella ictaluri in situ in histological sections from channel catfish Ictalurus punctatus using indirect immunohistochemistry with monoclonal antibodies Ed9 as a primary, and fluorescent FitC labeled antibodies as a secondary. This allowed for the detection of the bacterium using fluorescent microscopy.
1Laboratory of Molecular Immunology and Immunotherapy, Blood Research Institute, 2Department of Microbiology, Mount Sinai School of Medicine, 3Laboratory of Molecular Genetics, Blood Research Institute, 4City of Milwaukee Health Department Laboratory, 5Division of Hematology-Oncology/BMT, Children's Hospital of Wisconsin, Medical College of Wisconsin, 6Division of Hematology and Oncology, Dept Medicine, Medical College of Wisconsin
This method describes the use of Infrared dye based imaging system for detection of H1N1 in bronchioalveolar lavage (BAL) fluid of infected mice at a high sensitivity. This methodology can be performed in a 96- or 384-well plate, requires <10 μl volume of test material and has the potential for concurrent screening of multiple pathogens.
An efficient way to isolate lymphocytes from mouse genital tract is described. This method takes advantage of enzyme digestion and Percoll gradient separation to allow efficient isolation. This technique is also adaptable to for use in other species
Using Bioluminescent Imaging to Investigate Synergism Between Streptococcus pneumoniae and Influenza A Virus in Infant Mice
1Department of Microbiology and Immunology, University of Melbourne, 2Laboratory of Pediatric Infectious Diseases, Radboud University Nijmegen Medical Centre, 3The Centre for Dynamic Imaging, The Walter and Eliza Hall Institute for Medical Research
A concurrent infection with influenza A virus is one of the factors implicated in the induction of invasive pneumococcal disease during asymptomatic Streptococcus pneumoniae carriage. Here we describe a mixed infection method using infant mice to investigate the synergism between these two respiratory pathogens.
1Interdisciplinary Immunology Program, University of Iowa, and the VA Medical Center, 2Department of Biochemistry, University of Iowa, and the VA Medical Center, 3Department of Internal Medicine, University of Iowa, 4Department of Molecular Microbiology, Washington University School of Medicine, 5Division of Dermatology, Harbor-UCLA Medical Center, Hanley-Hardison Research Center, 6Interdisciplinary Immunology Program, Iowa City VA Medical Center, 7Departments of Internal Medicine, Microbiology and Epidemiology, University of Iowa
An in vivo imaging system is used to generate quantitative measurements of murine infection with the Trypanosomatid protozoan Leishmania. This is a non-invasive and non-lethal method for detecting parasites expressing luciferase within many tissues throughout the course of chronic Leishmania spp. infection.
Preparation and Pathogen Inactivation of Double Dose Buffy Coat Platelet Products using the INTERCEPT Blood System
This article describes the process used by Örebro University Hospital to produce double dose buffy coat platelet concentrates prepared from whole blood donations and treated with the INTERCEPT Blood System for pathogen inactivation. The in vitro quality of the final platelet units are evaluated over 7 days of storage.
Establish a chronic bacterial infected mouse model with persistent Salmonella typhimurium colonization in intestine for 27 weeks.
Cellular viability depends on timely and efficient management of protein misfolding. Here we describe a method for visualizing the different potential fates of a misfolded protein: refolding, degradation, or sequestration in inclusions. We demonstrate the use of a folding sensor, Ubc9ts, for monitoring proteostasis and aggregation quality control in live cells using 4D microscopy.
Anti-retroviral therapy to treat HIV/AIDS is monitored in South Africa on a large scale. Flow cytometry is combined for haematology (CD45), immunology (CD4) and viral-load linked CD38 assay. Recorded at NHLS-SA laboratories, Johannesburg, these modern methods are cost-efficient with heightened local internal quality control, serving as role-models for resource-limited diagnostics.
Here, we describe a non-invasive two-photon (2P) microscopy approach to study leukocyte homing in the mouse footpad. We discuss the technical aspects of our tissue imaging preparation and walk the reader through a typical experiment from initial set up to execution and data collection.
1Microbiology and Pathogenesis Activity, Bacterial Diseases Branch, Division of Vector-Borne Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, 2Tick-Borne Diseases Activity, Bacterial Diseases Branch, Division of Vector-Borne Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention
The collection of infected tick hemolymph, salivary glands, and saliva is important to study how tick-borne pathogens cause disease. In this protocol we demonstrate how to collect hemolymph and salivary glands from feeding Ixodes scapularis nymphs. We also demonstrate saliva collection from female I. scapularis adults.
The Citrobacter rodentium Mouse Model: Studying Pathogen and Host Contributions to Infectious Colitis
Citrobacter rodentium infection provides a valuable model to study enteric bacterial infections as well as host immune responses and colitis in mice. This protocol outlines the measurement of barrier integrity, pathogen load and histological damage allowing for the thorough characterization of pathogen and host contributions to murine infectious colitis.
1Department of Microbiology and Immunology, Tulane University Medical School, 2Physician/Scientist Program, Tulane University Medical School, 3Department of Molecular and Cellular Biology, Baylor College of Medicine
Traditional, two dimensional cell culture techniques often result in altered characteristics with respect to differentiation markers, cytokines and growth factors. Three-dimensional cell culture in the rotating cell culture system (RCCS) reestablishes expression of many of these factors as shown here with an extravillous trophoblast cell line.
1Respiratory Infection Group, Liverpool School of Tropical Medicine, 2Royal Liverpool and Broadgreen, University Hospital Trust, 3Comprehensive Local Research Network, 4NIHR Biomedical Research Centre in Microbial Diseases, Royal Liverpool and Broadgreen University Hospitals NHS Trust, 5Institute of Lung Health, Respiratory Biomedical Unit, University Hospitals of Leicester NHS Trust & University of Leicester, 6Department of Clinical Infection Microbiology & Immunology, Institute of Infection & Global Health, University of Liverpool
Experimental human pneumococcal carriage offers a natural model of carriage and a potential model for use in vaccine development. This technique is valuable yet complex and involves clinical risk by introducing a pathogen into a human. We have developed a detailed protocol.
In this candid interview, Anthony A. James explains how mosquito genetics can be exploited to control malaria and dengue transmission. Population replacement strategy, the idea that transgenic mosquitoes can be released into the wild to control disease transmission, is introduced as well as the concept of genetic drive and the design criterion for an effective genetic drive system. The ethical considerations of releasing genetically-modified organisms into the wild are also discussed.
1Department of Molecular Biology and Biochemistry, University of California, Irvine (UCI), 2Department of Molecular Biology and Biochemistry, Department of Microbiology and Molecular Genetics, University of California, Irvine (UCI)
The mosquito midgut and salivary glands are key entry and exit points for vector pathogens like Plasmodium falciparum and the dengue virus. This video demonstrates the dissection techniques for removing the midgut and salivary glands from Aedes aegypti mosquitoes.
Charles Taylor and John Marshall explain the utility of mathematical modeling for evaluating the effectiveness of population replacement strategy. Insight is given into how computational models can provide information on the population dynamics of mosquitoes and the spread of transposable elements through A. gambiae subspecies. The ethical considerations of releasing genetically modified mosquitoes into the wild are discussed.
Population Replacement Strategies for Controlling Vector Populations and the Use of Wolbachia pipientis for Genetic Drive
In this interview, Jason Rasgon explains the concept of genetic drive and the characteristics of an effective gene drive system. The use of the endosymbiotic bacterium, Wolbachia pipientis, as a means to spread genes through mosquito populations, is hypothesized.
This video describes a method for purifying Wolbachia pipientis from an Anopheles gambiae cell line and then culturing the endosymbiont in cell-free medium. An assay for viability of the bacterium is demonstrated.
This video illustrates the general techniques used to rear Anopheles gambiae in the laboratory. The methods for caring for laboratory mosquitoes are demonstrated through all stages of the organism's life cycle from larvae to pupae to blood-feeding adults.
Once a gene is identified as potentially refractory for the dengue virus, it must be evaluated for it's role in preventing viral infections within the mosquito. This protocol illustrates how the extent of dengue infections of mosquitoes can be assayed. The techniques for growing up the virus in culture, membrane feeding mosquitoes human blood, and assaying viral titers in the mosquito midgut are demonstrated.
1Dynamac, Inc., 2Department of Biological Sciences, University of Cincinnati, McMicken College of Arts and Science, 3Animal Parasitic Disease Laboratory, Agricultural Research Service, U.S. Department of Agriculture, 4National Exposure Research Laboratory, US Environmental Protection Agency
This study describes the development of a modified CsCl method that easily purifies T. gondii oocysts from feces of infected cats that are suitable for molecular biological and tissue culture manipulation
Specific Marking of HIV-1 Positive Cells using a Rev-dependent Lentiviral Vector Expressing the Green Fluorescent Protein
We have developed a lentiviral vector that possesses, in addition to the Tat-responsive LTR, the Rev-response element (RRE) that can regulate reporter gene expression in an HIV-1 Tat- and Rev-dependent fashion. The vector permits the specific detection of replicating HIV in living cells via the expression of GFP.
Transfection and Mutagenesis of Target Genes in Mosquito Cells by Locked Nucleic Acid-modified Oligonucleotides
Oligonucleotides can be used to site specifically substitute a single nucleotide of transfected target genes in both Anopheles gambiae and Anopheles stephensi cells.
Methods for using alphavirus transducing systems to express fluorescent reporters in vitro and in adult mosquitoes are described. This technique may be adapted to express any protein of interest in lieu of or in addition to a reporter.
Genetic crosses of rodent malaria parasites are performed by feeding two genetically distinct parasites to mosquitoes. Recombinant progeny are cloned from mouse blood after allowing mosquitoes to bite infected mice. This video shows how to produce genetic crosses of Plasmodium yoelii and is applicable to other rodent malaria parasites.
Bioimaging methods used to assess cell biodistribution of nanoparticles are applicable for therapeutic and diagnostic monitoring of nanoformulated compounds. The methods described herein are sensitive and specific when assessed by histological coregistration. The methodologies provide a translational pathway from rodent to human applications.
A method for RNA interference (RNAi) by injection of dsRNA into unfed ticks is described. RNAi is the most widely used gene-silencing technique in ticks where the use of other methods of genetic manipulation has been limited.
This article describes the procedure for the formation and visualization of a bacterial biofilm grown within an 8-well chamber slide
An accurate, short, sophisticated and cheap method is described that assesses telomere length in multiple tissues and species using qRT-PCR. In addition, we will describe a simple assay to assess telomerase activity as a complementary backbone test for telomere length.
The Virochip is a pan-viral microarray designed to simultaneously detect all known viruses as well as novel viruses on the basis of conserved sequence homology. Here we demonstrate how to run a Virochip assay to analyze clinical samples for the presence of both known and unknown viruses.
Protocols for Vaginal Inoculation and Sample Collection in the Experimental Mouse Model of Candida vaginitis
Key techniques to be used in the evaluation of Candida vaginitis in an experimental animal model are described. The methods will allow rapid collection of vaginal specimens and lymphocytes from draining lumbar lymph nodes. These techniques could give rise to mouse models of other diseases in the female lower genital tract.
This article describes the administration of lux-tagged bacteria to mice and subsequent in vivo analysis using IVIS bioluminescence imaging.
Detection of Invasive Pulmonary Aspergillosis in Haematological Malignancy Patients by using Lateral-flow Technology
A rapid and accurate point-of-care test for invasive pulmonary aspergillosis is presented. It takes advantage of lateral-flow technology using a specific monoclonal antibody that binds to an Aspergillus antigen secreted during pulmonary infections. The assay is compatible with serum and brochoalveolar lavage and represents a novel adjunct test for disease diagnosis.
1Department of Ophthalmology, Massachusetts Eye and Ear, 2JoVE Content Production
Here's a look at what's coming up in the February 2013 Issue of Journal of Visualized Experiments (JoVE).
Protein misfolding cyclic amplification (PMCA) is an in vitro assay for the study of prion conversion and strain and species barriers. It can also be used as a prion detection assay.
Most studies of herpetic corneal disease use a primary infection model. However, primary infection with HSV-1 does not typically lead to human disease. Here we describe a recurrent model of herpetic corneal disease, which more closely mimics human disease.
We report development of a negative selection system in E. histolytica based upon transgenic expression of a chimeric protein (FCU1) and selection with the prodrug 5-fluorocytosine. The FCU1 protein is a fusion of yeast cytosine deaminase and uracil phosphoribosyltransferase. Expression of FCU1 resulted in increased E. histolytica sensitivity towards 5-fluorocytosine.
Blood vessels as a target for infection, Paris center for cardiovascular research, INSERM U970
During the infection process, a key step is the adhesion of pathogens with host cells. In most instances this adhesion step occurs in the presence of mechanical stress generated by flowing liquid. We describe a technique that introduces shear stress as an important parameter in the study of bacterial adhesion.
Among the three mosquito genera, namely Anopheles, Aedes, and Culex, physical genome mapping techniques were established only for Anopheles, whose members possess readable polytene chromosomes. For the genera of Aedes and Culex, however, cytogenetic mapping remains challenging because of the poor quality of polytene chromosomes. Here we present a universal protocol for obtaining high-quality preparations of mitotic chromosomes and an optimized FISH protocol for all three genera of mosquitoes.
Enumeration of Major Peripheral Blood Leukocyte Populations for Multicenter Clinical Trials Using a Whole Blood Phenotyping Assay
In this report, we demonstrate the staining and analysis steps of a phenotyping assay performed on fresh whole blood to enumerate major innate and adaptive leukocyte populations. We emphasize considerations for performing these procedures in the context of a multicenter clinical trial.
Using Reverse Genetics to Manipulate the NSs Gene of the Rift Valley Fever Virus MP-12 Strain to Improve Vaccine Safety and Efficacy
The reverse genetics system for the Rift Valley fever virus MP-12 vaccine strain is a useful tool for creating additional MP-12 mutants with increased attenuation and immunogenicity. We describe the protocol to generate and characterize NSs mutant strains.
Microbial biofilms are generally constituted by distinct subpopulations of specialized cells. Single-cell analysis of these subpopulations requires the use of fluorescent reporters. Here we describe a protocol to visualize and monitor several subpopulationswithin B. subtilis biofilms using fluorescence microscopy and flow cytometry.