Errant HIV strain renders test virus stock useless

Science ◽  
1992 ◽  
Vol 256 (5062) ◽  
pp. 1387-1388 ◽  
Author(s):  
J Palca
Keyword(s):  
Virus Stock ◽  
Test Virus

scholarly journals FURTHER CHARACTERIZATION OF THE ADENOVIRUS ERYTHROCYTE RECEPTOR-MODIFYING FACTOR

1961 ◽  
Vol 114 (5) ◽  
pp. 717-728 ◽  
Author(s):  
Julius A. Kasel ◽  
Wallace P. Rowe ◽  
John L. Nemes
Keyword(s):  
Infectious Virus ◽  
Rabbit Antiserum ◽  
Human Erythrocytes ◽  
Red Cells ◽  
Tissue Cultures ◽  
Test Virus

Agglutinability of human erythrocytes for 3 hemagglutinating adenoviruses was markedly reduced by pretreatment of red cells with a factor present in tissue cultures which had been infected with adenovirus types 1, 2,4, or 15. The factor responsible for erythrocyte receptor modification was non-dialyzable and unaffected by the action of ribonuclease, desoxyribonuclease, trypsin, chymotrypsin, or ether. The factor was smaller, more thermostable, and separable from the infectious virus. Erythrocyte receptor modification was found to be a function of time and temperature. Titers of erythrocyte receptor-modifying activity were not diminished by successive exposures to fresh erythrocytes. Erythrocytes treated with erythrocyte receptor-modifying factor suspensions failed to significantly adsorb test virus hemagglutinin. Inhibition of erythrocyte receptor modifying-activity of the adenovirus suspensions by rabbit antiserum was type-specific.

scholarly journals Trans-complementation of a genetic defect in the coxsackie B3 virus 2B protein

2002 ◽  
Vol 83 (2) ◽  
pp. 341-350 ◽  
Author(s):  
Frank J. M. van Kuppeveld ◽  
Patrick J. J. C. van den Hurk ◽  
Ina W. J. Schrama ◽  
Jochem M. D. Galama ◽  
Willem J. G. Melchers
Keyword(s):  
Glutamic Acid ◽  
Genetic Defect ◽  
Wild Type Virus ◽  
Wild Type ◽  
Virus Stock ◽  
Rna Transcripts ◽  
Observation Sequence ◽  
2B Protein ◽  
Α Helix ◽  
Positively Charged

The enterovirus 2B protein contains a putative amphipathic α-helix that includes three positively charged and one negatively charged residue. Previously, we observed that replacement of the glutamic acid-40 residue with a lysine residue (mutation 2B-E[40]K) in the amphipathic α-helix of the coxsackie B3 virus 2B protein resulted in a quasi-infectious phenotype. On one occasion, however, transfection of 2B-E[40]K RNA transcripts gave rise to a virus stock in which the mutation was retained. This study was aimed at elucidating the molecular mechanism underlying this observation. Sequence analysis of the viral RNA provided no evidence for a second-site suppression mutation that rescued the defect of the 2B-E[40]K mutation in cis. Therefore, the possibility was considered that the defect caused by the 2B-E[40]K mutation was complemented in trans by viable revertants that had emerged in the virus population. The transfection-derived virus stock indeed contained a small fraction of (pseudo)revertant viruses, carrying the original glutamic acid-40, threonine-40 or asparagine-40, rather than the introduced lysine-40. Consistent with the idea that the 2B-E[40]K virus is unable to grow without the aid of trans-acting wild-type(-like) proteins, only the (pseudo)revertant viruses were able to produce individual plaques. Further support for the idea of trans-rescue was obtained using a genetic complementation assay, which revealed the occurrence of a low level of trans-complementation of the 2B-E[40]K mutation by wild-type virus. This is the first report that provides evidence that a genetic defect in the enterovirus 2B protein can be complemented in trans.

Comparison of RE Virus (Strain T) With the Visceral Lymphomatosis Agent

1967 ◽  
Vol 25 ◽  
pp. 114-115
Author(s):  
R. F. Zeigel ◽  
G. H. Theilen ◽  
P. Sarma
Keyword(s):  
Japanese Quail ◽  
Virus Strain ◽  
Virus Budding ◽  
Virus Stock ◽  
Turkey Poults

Theilen, Zeigel and Twiehaus, '66 and Zeigel, Theilen and Twiehaus, '66 reported biological and morphological observations on a virus which was originally derived from adult turkeys and which produced reticuloendotheliosis after inoculation into chicks, turkey poults, and Japanese quail. These publications indicated differences between the RE virus and the agent of visceral lymphomatosis. Because of the difficulty in obtaining absolutely R I F free embryos and chicks for experimental purposes, it was fortuitous that the early studies were not confused by contamination of the RE virus stock. Ultimately, during the final phases of the studies, some cultures utilized for R I F and C O F A L, tests became doubly infected. It is the purpose of this note to present further observations on the characteristics of the immature developing RE virus (budding forms) and to show the RE virus and the R I F agent, simultaneously, in the contaminated cultures.

In Vitro Efficacy of “Essential Iodine Drops” Against Severe Acute Respiratory Syndrome-Coronavirus 2 (SARS-CoV-2)

2020 ◽  
Author(s):  
Köntös Zoltán
Keyword(s):  
Severe Acute Respiratory Syndrome ◽  
Room Temperature ◽  
Cytopathic Effect ◽  
Virucidal Activity ◽  
Virus Stock ◽  
Infectious Dose ◽  
Strain Virus ◽  
Respiratory Droplets ◽  
Elemental Iodine

AbstractBackgroundAerosolization of respiratory droplets is considered the main route of coronavirus disease 2019 (COVID-19). Therefore, reducing the viral load of Severe Acute Respiratory Syndrome-Coronavirus 2 (SARS-CoV-2) shed via respiratory droplets is potentially an ideal strategy to prevent the spread of the pandemic. The in vitro virucidal activity of intranasal Povidone-Iodine (PVP-I) has been demonstrated recently to reduce SARS-CoV-2 viral titres. This study evaluated the virucidal activity of the aqueous solution of Iodine-V (a clathrate complex formed by elemental iodine and fulvic acid) as in Essential Iodine Drops (EID) with 200 μg elemental iodine/ml content against SARS-CoV-2 to ascertain whether it is a better alternative to PVP-I.MethodsSARS-CoV-2 (USAWA1/2020 strain) virus stock was prepared by infecting Vero 76 cells (ATCC CRL-1587) until cytopathic effect (CPE). The virucidal activity of EID against SARS-CoV-2 was tested in three dilutions (1:1; 2:1 and 3:1) in triplicates by incubating at room temperature (22 ± 2°C) for either 60 or 90 seconds. The surviving viruses from each sample were quantified by a standard end-point dilution assay.ResultsEID (200 μg iodine/ml) after exposure for 60 and 90 seconds was compared to controls. In both cases, the viral titre was reduced by 99% (LRV 2.0). The 1:1 dilution of EID with virus reduced SARS-CoV-2 virus from 31,623 cell culture infectious dose 50% (CCCID50) to 316 CCID50 within 90 seconds.ConclusionSubstantial reductions in LRV by Iodine-V in EID confirmed the activity of EID against SARS-CoV-2 in vitro, demonstrating that Iodine-V in EID is effective at inactivating the virus in vitro and therefore suggesting its potential application intranasally to reduce SARS-CoV-2 transmission from known or suspected COVID-19 patients.

scholarly journals Cloned Genomic DNA of Type 2 Porcine Circovirus Is Infectious When Injected Directly into the Liver and Lymph Nodes of Pigs: Characterization of Clinical Disease, Virus Distribution, and Pathologic Lesions

2002 ◽  
Vol 76 (2) ◽  
pp. 541-551 ◽  
Author(s):  
M. Fenaux ◽  
P. G. Halbur ◽  
G. Haqshenas ◽  
R. Royer ◽  
P. Thomas ◽  
...  
Keyword(s):  
Lymph Nodes ◽  
Plasmid Dna ◽  
Genomic Dna ◽  
Clinical Signs ◽  
Porcine Circovirus ◽  
Live Virus ◽  
Virus Stock ◽  
Molecular Clone ◽  
Pathologic Lesions

ABSTRACT Infection of animals with a molecular viral clone is critical to study the genetic determinants of viral replication and virulence in the host. Type 2 porcine circovirus (PCV2) has been incriminated as the cause of postweaning multisystemic wasting syndrome (PMWS), an emerging disease in pigs. We report here for the first time the construction and use of an infectious molecular DNA clone of PCV2 to characterize the disease and pathologic lesions associated with PCV2 infection by direct in vivo transfection of pigs with the molecular clone. The PCV2 molecular clone was generated by ligating two copies of the complete PCV2 genome in tandem into the pBluescript SK (pSK) vector and was shown to be infectious in vitro when transfected into PK-15 cells. Forty specific-pathogen-free pigs at 4 weeks of age were randomly assigned to four groups of 10 each. Group 1 pigs served as uninoculated controls. Pigs in group 2 were each inoculated intranasally with about 1.9 × 105 50% tissue culture infective doses of a homogeneous PCV2 live virus stock derived from the molecular clone. Pigs in group 3 were each injected intrahepatically with 200 μg of the cloned PCV2 plasmid DNA, and pigs in group 4 were each injected into the superficial iliac lymph nodes with 200 μg of the cloned PCV2 plasmid DNA. Animals injected with the cloned PCV2 plasmid DNA developed infection resembling that induced by intranasal inoculation with PCV2 live virus stock. Seroconversion to PCV2-specific antibody was detected in the majority of pigs from the three inoculated groups at 35 days postinoculation (DPI). Viremia, beginning at 14 DPI and lasting 2 to 4 weeks, was detected in the majority of the pigs from all three inoculated groups. There were no remarkable clinical signs of PMWS in control or any of the inoculated pigs. Gross lesions in pigs of the three inoculated groups were similar and were characterized by systemically enlarged, tan lymph nodes and lungs that failed to collapse. Histopathological lesions and PCV2-specific antigen were detected in numerous tissues and organs, including brain, lung, heart, kidney, tonsil, lymph nodes, spleen, ileum, and liver of infected pigs. This study more definitively characterizes the clinical course and pathologic lesions exclusively attributable to PCV2 infection. The data from this study indicate that the cloned PCV2 genomic DNA may replace infectious virus for future PCV2 pathogenesis and immunization studies. The data also suggest that PCV2, although essential for development of PMWS, may require other factors or agents to induce the full spectrum of clinical signs and lesions associated with advanced cases of PMWS.

scholarly journals Rapid Genome Assembly and Comparison Decode Intrastrain Variation in Human Alphaherpesviruses

mBio ◽  
2015 ◽  
Vol 6 (2) ◽  
Author(s):  
Lance R. Parsons ◽  
Yolanda R. Tafuri ◽  
Jacob T. Shreve ◽  
Christopher D. Bowen ◽  
Mackenzie M. Shipley ◽  
...  
Keyword(s):  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Genome Assembly ◽  
Viral Genome ◽  
Recurrent Disease ◽  
Virus Stock ◽  
New Approach ◽  
Epithelial Lesions ◽  
Simplex Virus ◽  
Hsv 1

ABSTRACTHerpes simplex virus (HSV) is a widespread pathogen that causes epithelial lesions with recurrent disease that manifests over a lifetime. The lifelong aspect of infection results from latent viral infection of neurons, a reservoir from which the virus reactivates periodically. Recent work has demonstrated the breadth of genetic variation in globally distributed HSV strains. However, the amount of variation or capacity for mutation within one strain has not been well studied. Here we developed and applied a streamlined new approach for assembly and comparison of large DNA viral genomes such as HSV-1. This viral genome assembly (VirGA) workflow incorporates a combination ofde novoassembly, alignment, and annotation strategies to automate the generation of draft genomes for large viruses. We applied this approach to quantify the amount of variation between clonal derivatives of a common parental virus stock. In addition, we examined the genetic basis for syncytial plaque phenotypes displayed by a subset of these strains. In each of the syncytial strains, we found an identical DNA change, affecting one residue in the gB (UL27) fusion protein. Since these identical mutations could have appeared after extensivein vitropassaging, we applied the VirGA sequencing and comparison approach to two clinical HSV-1 strains isolated from the same patient. One of these strains was syncytial upon first culturing; its sequence revealed the same gB mutation. These data provide insight into the extent and origin of genome-wide intrastrain HSV-1 variation and present useful methods for expansion toin vivopatient infection studies.IMPORTANCEHerpes simplex virus (HSV) infects more than 70% of adults worldwide, causing epithelial lesions and recurrent disease that manifests over a lifetime. Prior work has demonstrated that HSV strains vary from country to country and between individuals. However, the amount of variation within one strain has not been well studied. To address this, we developed a new approach for viral genome assembly (VirGA) and analysis. We used this approach to quantify the amount of variation between sister clones of a common parental virus stock and to determine the basis of a unique fusion phenotype displayed by several variants. These data revealed that while sister clones of one HSV stock are more than 98% identical, these variants harbor enough genetic differences to change their observed characteristics. Comparative genomics approaches will allow us to explore the impacts of viral inter- and intrastrain diversity on drug and vaccine efficacy.

A Polymerase Chain Reaction–Based Method for the Detection of Hepatitis A Virus in Produce and Shellfish

2002 ◽  
Vol 65 (2) ◽  
pp. 393-402 ◽  
Author(s):  
BISWENDU B. GOSWAMI ◽  
MICHAEL KULKA ◽  
DIANA NGO ◽  
PHILLIP ISTAFANOS ◽  
THOMAS A. CEBULA
Keyword(s):  
Polymerase Chain Reaction ◽  
Hepatitis A ◽  
Hepatitis A Virus ◽  
General Procedure ◽  
Pcr Analysis ◽  
Genomic Rna ◽  
Chain Reaction ◽  
Viral Origin ◽  
Polymerase Chain ◽  
Test Virus

Outbreaks of gastroenteritis that are suspected to be of viral origin are on the rise. Thus, there is a need for regulatory agencies entrusted with food safety to develop adequate techniques for the detection of viruses in foods. We have established a general procedure for the detection of hepatitis A virus (HAV) in shellfish that, with minor modifications, is also applicable to fresh produce such as cilantro. Total RNA was isolated from shellfish or cilantro, followed by isolation of poly(A)-containing RNA. Because HAV genomic RNA contains a poly(A) tail, the isolation of poly(A)-containing RNA also enriches HAV genomic RNA. Reverse transcription was used to convert the RNA to cDNA, and then amplification was carried out by polymerase chain reaction (PCR). Reamplification with internal primers was used to improve the quality and the quantity of amplified DNA, allowing for post-PCR analysis such as sequence identification of the viral strain. With this procedure, multiple samples could be analyzed in four working days by a single trained individual. The nominal sensitivity of detection of the procedure was 0.15 TCID50 (50% tissue culture infective dose) per 0.62 g of tissue with a test virus. The direct RNA isolation protocol avoided pitfalls associated with whole-virus purification procedures by replacing virus precipitation steps involving polyethylene glycol and Procipitate with phenol extraction. The method is straightforward and reliable. We successfully used this procedure to detect naturally occurring HAV in clams involved in a gastroenteritis outbreak, as well as in cilantro artificially contaminated with a test virus.

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