Articles by Priscilla L. Williams in JoVE
Biocontainment 내 바이러스 샘플의 음성 염색을위한 캡슐의 활용 Candace D. Blancett1, Mitchell K. Monninger1, Chrystal A. Nguessan1, Kathleen A. Kuehl1, Cynthia A. Rossi2, Scott P. Olschner2, Priscilla L. Williams2, Steven L. Goodman3, Mei G. Sun1 1Pathology Division, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), 2Diagnostic Systems Division, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), 3Microscopy Innovations LLC 이 프로토콜은 BSL-2, -3 또는 -4 실험실에서 쉽게 사용할 수있는 음성 염색 바이러스 샘플을 제공합니다. 여기에는 투과 전자 현미경 그리드를 보호하고 생체 내에서 난기류 환경에서 사용자가보다 쉽게 취급 할 수있게 해주는 혁신적인 가공 캡슐의 사용이 포함됩니다.
Other articles by Priscilla L. Williams on PubMed
Evaluation of ViroCyt® Virus Counter for Rapid Filovirus Quantitation Viruses. Feb, 2015 | Pubmed ID: 25710889 Development and evaluation of medical countermeasures for diagnostics, vaccines, and therapeutics requires production of standardized, reproducible, and well characterized virus preparations. For filoviruses this includes plaque assay for quantitation of infectious virus, transmission electron microscopy (TEM) for morphology and quantitation of virus particles, and real-time reverse transcription PCR for quantitation of viral RNA (qRT-PCR). The ViroCyt® Virus Counter (VC) 2100 (ViroCyt, Boulder, CO, USA) is a flow-based instrument capable of quantifying virus particles in solution. Using a proprietary combination of fluorescent dyes that stain both nucleic acid and protein in a single 30 min step, rapid, reproducible, and cost-effective quantification of filovirus particles was demonstrated. Using a seed stock of Ebola virus variant Kikwit, the linear range of the instrument was determined to be 2.8E+06 to 1.0E+09 virus particles per mL with coefficient of variation ranging from 9.4% to 31.5% for samples tested in triplicate. VC particle counts for various filovirus stocks were within one log of TEM particle counts. A linear relationship was established between the plaque assay, qRT-PCR, and the VC. VC results significantly correlated with both plaque assay and qRT-PCR. These results demonstrated that the VC is an easy, fast, and consistent method to quantify filoviruses in stock preparations.
Preparation of Viral Samples Within Biocontainment for Ultrastructural Analysis: Utilization of an Innovative Processing Capsule for Negative Staining Journal of Virological Methods. Dec, 2016 | Pubmed ID: 27751950 Transmission electron microscopy can be used to observe the ultrastructure of viruses and other microbial pathogens with nanometer resolution. In a transmission electron microscope (TEM), the image is created by passing an electron beam through a specimen with contrast generated by electron scattering from dense elements in the specimen. Viruses do not normally contain dense elements, so a negative stain that places dense heavy metal salts around the sample is added to create a dark border. To prepare a virus sample for a negative stain transmission electron microscopy, a virus suspension is applied to a TEM grid specimen support, which is a 3mm diameter fragile specimen screen coated with a few nanometers of plastic film. Then, deionized (dI) water rinses and a negative stain solution are applied to the grid. All infectious viruses must be handled in a biosafety cabinet (BSC) and many require a biocontainment laboratory environment. Staining viruses in biosafety levels (BSL) 3 and 4 is especially challenging because the support grids are small, fragile, and easily moved by air currents. In this study we evaluated a new device for negative staining viruses called mPrep/g capsule. It is a capsule that holds up to two TEM grids during all processing steps and for storage after staining is complete. This study reports that the mPrep/g capsule method is valid and effective to negative stain virus specimens, especially in high containment laboratory environments.
Corning HYPERFlask(®) for Viral Amplification and Production of Diagnostic Reagents Journal of Virological Methods. Apr, 2017 | Pubmed ID: 28012899 Viral preparations are essential components in diagnostic research and development. The production of large quantities of virus traditionally is done by infecting numerous tissue culture flasks or roller bottles, which require large incubators and/or roller bottle racks. The Corning HYPERFlask(®) is a multilayer flask that uses a gas permeable film to provide gas exchange between the cells and culture medium and the atmospheric environment. This study evaluated the suitability of the HYPERFlask for production of Lassa, Ebola, Bundibugyo, Reston, and Marburg viruses and compared it to more traditional methods using tissue culture flasks and roller bottles. The HYPERFlask produced cultures were equivalent in virus titer and indistinguishable in immunodiagnostic assays. The use of the Corning HYPERFlask for viral production is a viable alternative to traditional tissue culture flasks and roller bottles. HYPERFlasks allow for large volumes of virus to be produced in a small space without specialized equipment.