Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Reporter virus”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 343 records · Page 19Linked to original sources
PubMed2003

Molecular characterization of a carnation etched ring virus isolate from India.

Incidence of the Carnation etched ring virus (CERV), the only DNA virus reported to date on carnation, was investigated by a bioassay using a partially purified virus as inoculum and then by a double-antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA). Out of 61 carnation cultivars analyzed 41 (67%) were found positive. The virus positivity was verified by polymerase chain reaction (PCR) and nucleotide sequencing. The amplified 1349 bp fragment was by about 98% and 96% identical with respect to coat protein (CP) and enzymatic polyprotein genes, respectively, as compared to the sequences available in the database. In terms of amino acid sequence similarity, the homology values were 99% and 97%, respectively. Comparison with other caulimoviruses revealed that CERV is most closely related to the Cauliflower mosaic virus (CaMV). High genetic stability of CERV may be attributed to the fact that it has evolved from the same initial sequence in an original host. Because of global market of cut flowers and vegetative propagation it has been dispersed around the world.

Amino Acid Sequence↗
PubMed2025

Generation of Biologically Contained Marburg Virus.

Wild-type Marburg virus (MARV) can only be handled in biosafety level 4 facilities. By removing an essential gene from the virus genome, deficient virus particles can be generated that are only capable of replication if the missing gene product is provided in trans. As a result, these viruses are restricted to specific cell lines, making them safe to handle at lower biosafety levels. Here, we provide a detailed overview of how to generate MARV in which the VP30 gene has been replaced by a green fluorescent reporter gene, as well as how to use lentiviral transduction to create stable cell lines expressing MARV VP30. These cell lines can be used for the propagation and confinement of the resulting reporter virus.

Marburgvirus↗
PubMed1991

Electron microscopic reporting of gastrointestinal viruses in the United Kingdom, 1985-1987.

We examined some epidemiological features of the viruses associated with gastrointestinal illness, using national data reported by electron microscopists in the United Kingdom. During the 3 years analyzed (1985-1987), a total of 1,993 positive detections of astroviruses, caliciviruses, coronaviruses, and small round structured viruses (SRSVs) were reported. In 1 year of this period, 8,210 rotaviruses were reported. More than 90% of the astroviruses and caliciviruses were detected in children under 5 years of age, while coronaviruses and SRSVs were detected in adults as well as children. Detections of astroviruses increased in the winter and were infrequent during the summer, a seasonal pattern similar to that observed for rotaviruses. There was some variability between reporting regions in rates of detection of fecal viruses. We have attempted to identify the reasons for this. We make suggestions for improving the detection of human fecal viruses, and we recognize the need for continued surveillance of these agents.

Adolescent↗
PubMed2005

High-throughput assays using a luciferase-expressing replicon, virus-like particles, and full-length virus for West Nile virus drug discovery.

Many flaviviruses cause significant human disease worldwide. The development of flavivirus chemotherapy requires reliable high-throughput screening (HTS) assays. Although genetic systems have been developed for many flaviviruses, their usage in antiviral HTS assays has not been well explored. Here we compare three cell-based HTS assays for West Nile virus (WNV) drug discovery: (i) an assay that uses a cell line harboring a persistently replicating subgenomic replicon (containing a deletion of viral structural genes), (ii) an assay that uses packaged virus-like particles containing replicon RNA, and (iii) an assay that uses a full-length reporting virus. A Renilla luciferase gene was engineered into the replicon or into the full-length viral genome to monitor viral replication. Potential inhibitors could be identified through suppression of luciferase signals upon compound incubation. The antiviral assays were optimized in a 96-well format, validated with known WNV inhibitors, and proved useful in identifying a new inhibitor(s) through HTS of a compound library. In addition, because each assay encompasses multiple but discrete steps of the viral life cycle, the three systems could potentially be used to discriminate the mode of action of any inhibitor among viral entry (detected by assays ii and iii but not by assay i), replication (including viral translation and RNA synthesis; detected by assays i to iii), and virion assembly (detected by assay iii but not by assays i and ii). The approaches described in this study should be applicable to the development of cell-based assays for other flaviviruses.

Antiviral Agents↗
PubMed1977

Hepatitis-B virus in bedbugs (Cimex hemipterus) from Senegal.

Bedbugs of the species Cimex hemipterus (F) were collected on four separate occasions from the bedding in the huts of village dwellers in Senegal, West Africa. Hepatitis-B surface antigen (HBSAg) was detected in unengorged nymph and adult bedbugs in each of the first three collections. 3 of 28 such specimens were HBSAg(+) in the first collection and 3 of 17 specimens were positive in the second collection. In the third, 6 of 9 were HBSAg(+) when the bed occupant was known to be HBSAg(+). 2 of these 6 positive insects did not contain human serum proteins. Bedbugs in the fourth collection were captured and kept alive without a blood meal for 30 days. 3 of 89 of these samples were HBSAg(+). These are the highest field infection-rates of hepatitis-B virus reported in any insect species. The bedbug must be considered a potential vector of hepatitis-B virus.

Adolescent↗
PubMed2005

The detection of lumpy skin disease virus in samples of experimentally infected cattle using different diagnostic techniques.

Lumpy skin disease (LSD) is a disease of cattle, primarily in Africa and Madagascar and rarely in the Middle East. It is caused by a capripoxvirus that belongs to the family Poxviridae. The disease is of economic importance in endemic areas. Effective control of LSD requires accurate and rapid laboratory techniques to confirm a tentative clinical diagnosis. Comparative studies on different diagnostic tests used at different stages of the disease have not been done. The aim of this study was to compare several of these tests. Six seronegative bulls, between 11 and 20 months of age, were infected intravenously and kept in an insect-free facility. The course of the infection was monitored. During a 3-month period blood samples and skin biopsies were collected for virus isolation and polymerase chain reaction (PCR). Skin biopsies were also examined using transmission electron microscopy (TEM). The incubation period in infected animals varied from 4-5 days. The length of the viraemic period did not correlate with the severity of clinical disease. Viraemia was detected from 1-12 days using virus isolation and from 4-11 days using the PCR, which is longer than has previously been reported. Virus was isolated from skin biopsies until Day 39 post infection (p.i.) and PCR could demonstrate viral DNA until Day 92 p.i. Transmission electron microscopy of negatively stained skin biopsies detected LSD virus only in one of the four bulls that developed skin lesions until Day 33 p.i. The PCR was a fast and sensitive method to demonstrate viral DNA in blood and skin samples. It could detect viral nucleic acid in skin lesions 53 days longer than virus isolation. Virus isolation from blood and skin samples was sensitive and reliable, but as a single test it may be too time-consuming to use although this depends on how rapidly the diagnosis must be confirmed. In conclusion, this study showed the PCR to be superior in detecting LSD virus from blood and skin samples. However, virus isolation is still required when the infectivity of the LSD virus is to be determined.

Animals↗
PubMed1989

[Human immunodeficiency virus type 2 infection in Western Africans living in Catalonia].

We have studied retrospectively the presence of serologic markers of type 1 and type 2 human immunodeficiency virus infection in 102 subjects coming from West Africa and living in Catalonia. We have proven the presence of specific antibodies to type 2 human immunodeficiency virus in three asymptomatic subjects among whose epidemiologic antecedents the unique risk factor was heterosexual promiscuity. These three subjects are the first seropositive to type 2 human immunodeficiency virus reported in our country. In none of the studied cases serologic markers of type 1 human immunodeficiency virus infection were detected.

Acquired Immunodeficiency Syndrome↗
PubMedDate not supplied

Recognition and management of ARI--a KAP study on private medical practitioners.

We interviewed 113 private medical practitioners (PMPs) of all system of medicine in Ambedkar Nagar area of South Delhi to determine as to how they recognise and treat Acute Respiratory tract Infections (ARI) in children, in particular, pneumonia. Allopathic PMPs reported viruses and bacteria as causes of ARI as compared to PMPs of other system of medicine who often reported exposure to cold, change in weather and dietary habits as a cause of ARI. Sixty-eight PMPs out of 113 did not count the respiratory rate (RR) in children with ARI and among those who counted, only 19.5% PMPs could correctly tell the normal RR in children aged less than two months. In children aged 2-12 months, the percentage of PMPs responding correctly was 15.0%. Relatively greater proportion of PMPs (31.8%) could correctly tell the normal respiratory rate in children aged 1-5 years. X-ray to diagnose pneumonia was suggested by 102 (90.3%) PMPs. Majority of PMPs prescribed some form of medication including antibiotics for the treatment of cough and cold. Eighty-seven (77%) PMPs prescribed antibiotics, 53 (46.9%) antihistaminics and 49 (43.4%) prescribed allopathic cough syrups to treat cough and cold. For pneumonia, 108 (96.4%) PMPs prescribed antibiotics and 31 (27.7%) PMPs prescribed steroids among other things.

Adrenal Cortex Hormones↗
PubMed1997

The role of genotypic heterogeneity in wild type virus populations on the selection of nonnucleoside reverse transcriptase inhibitor-resistant viruses.

Virus populations were selected in cell culture using two widely used protocols in order to evaluate the role of selection methodology on the genotype and phenotype of nonnucleoside reverse transcriptase inhibitor resistant viruses. Selection was performed by serial passage of virus in the presence of gradually increasing concentrations of antiviral compound or passage in the presence of a constant high concentration of compound. Using the CEM-SS cell line, the IIIB strain of HIV-1, and identical nonnucleoside reverse transcriptase inhibitors, resistant viruses were obtained and their phenotypic and genotypic properties were defined. Resistant virus populations containing the Y181C amino acid change in the reverse transcriptase were predominantly selected with each of the tested compounds. Several of the compounds selected secondary amino acid changes using both methods. A comparison of the resistant viruses selected in our laboratory using each of the two protocols with viruses reported by a second laboratory employing one of the two methods suggests that genotypic differences in the selected virus isolates may most likely result from the variation in the genetic composition of the respective wild type virus pools, rather than the specific selection methodology employed. These results imply that HIV may select a wide variety of amino acid changes to avoid the inhibitory effects of the nonnucleoside reverse transcriptase inhibitors and the selection of compounds for clinical use in combination with agents possessing non-overlapping resistance phenotypes will require evaluation of the agents against virus isolates possessing each of the mutations known to confer drug resistance.

Anti-HIV Agents↗
PubMed1997

[Routine PCR screening for HBV, HCV and HIV-I genome in a large blood donation services--experiences and initial results].

We adapted the PCR method to screen up to 3,000 blood donations per day for HBV, HCV, and HIV-1 contamination. Concerning logistics: The first step is the generation of 3 identical microtiter plates (PT) by using the self-validated automatic sample processor with disposable tips. Using the first PT, we pooled up to 600 aliquots taken from blood donations which are serological negative and free for clinical usage according to actual federal regulations. In the case of a positive PCR pool result the viremic donation is identified by 2 additional PCR pool testing steps with smaller pool sizes using the second and third PT. All described steps are supported by electronic data processing. The PCR-method: After virus concentration by ultracentrifugation and--in case of HCV and HIV-1--additional reverse transcription PCR-amplifications were performed. PCR in two genomic regions are done for each virus. Laser-induced fluorescence detection after polyacrylamide gel electrophoresis and computer analysis were used to check the amplification products. Using this approach, a virus-containing donation can be detected in up to 599 negative samples with following sensitivity: HBV and HIV-1, 1,000-1,500 genome equivalents/ml; HCV, 2,000-2,500 genome equivalents/ml, thus sensitivity being in the range of commercial available PCR kits when testing nonpooled samples. The sensitivity was validated by using national and international available standards with known virus genome concentrations. All processing steps are checked using different controls such as, e.g., negative, positive, premix controls, reporter virus, inhibition controls. Routinely employing this validated methodology, we investigated 327,013 donations until the end of June 1996. During this survey, we found at least 16 virus-containing donations which are negative in corresponding serological tests and would have been transfused (4 HBV-, 13 HCV-, 0 HIV-1-containing donations), including one later seroconversion for HBV and one for HCV. Using our adapted PCR-methodology, it seems possible to shorten the diagnostic window periods with acceptable costs for large transfusion centers (15 DM per donation for all 3 viruses including all steps and investments). Therefore, PCR seems to become a new method of choice to prevent transfusion transmitted infections.

Blood Banks↗
PubMed2004

Poor validity of self-reported hepatitis B virus infection and vaccination status among young drug users.

Self-reported hepatitis B virus (HBV) infection status and immunization status were compared with HBV serological markers among 324 young injection drug users (IDUs) and noninjection drug users (NIDUs). The overall validity of self-reported status was poor; 52% claiming to be vaccinated were actually susceptible to HBV. There was no difference in validity of self-reported HBV status between IDUs and NIDUs. Clinicians should adopt a "Don't Ask, Vaccinate" vaccination policy for young drug users.

Adult↗
PubMed1992

The mode of cauliflower mosaic virus propagation in the plant allows rapid amplification of viable mutant strains.

We inoculated the leaves of turnip plants (Brassica campestris spp. rapa cv. Just Right) with two cauliflower mosaic viruses (CaMVs) with different small mutations in a dispensable region of the viral genome, and followed the spread of the virus infection through the plant. Surprisingly, analysis of viral DNA in single primary chlorotic lesions revealed the presence of both mutants. In contrast, the secondary chlorotic lesions and systemically infected leaves contained virus molecules of either one or the other type only. Infection of plants with different ratios of the two reporter viruses showed that this ratio is not conserved during systemic virus spread. Infection with CaMV DNA in the form of heteroduplexes containing a single mismatched base pair, in which each strand carried a distinct diagnostic marker, provided us with evidence that the mismatch was subjected to a repair process in the host plant.

Base Sequence↗
PubMed2002

Severe nucleoside-associated lactic acidosis in human immunodeficiency virus-infected patients: report of 12 cases and review of the literature.

Lactic acidosis is a rare but often fatal complication reported in some human immunodeficiency virus (HIV)-infected patients treated with nucleoside-analogue reverse-transcriptase inhibitors. We report a series of 12 patients with HIV infection treated with nucleoside analogues who developed unexplained metabolic acidosis. We have also reviewed 60 additional published cases. The aim of the present study is to describe the clinical picture, prognostic factors, and final outcome for nucleoside-associated lactic acidosis. The mortality rate is high: 33% for our patients, and 57% for the patients described in the literature. In the multivariate analysis, a lactate serum level of >10 mM (odds ratio [OR], 13.23; 95% confidence interval [CI], 2.96-59.25) was the only factor associated with higher mortality. The administration of specific therapy with cofactors against acidosis was associated with a lower mortality (OR, 0.17; 95% CI, 0.04-0.73). We conclude that specific therapy with cofactors may improve the outcome for patients with this syndrome.

Acidosis, Lactic↗
PubMed2005

Structural requirements for recognition of the human immunodeficiency virus type 1 core during host restriction in owl monkey cells.

Human immunodeficiency virus type 1 (HIV-1) infection of simian cells is restricted at an early postentry step by host factors whose mechanism of action is unclear. These factors target the viral capsid protein (CA) and attenuate reverse transcription, suggesting that they bind to the HIV-1 core and interfere with its uncoating. To identify the relevant binding determinants in the capsid, we tested the capacity of viruses containing Gag cleavage site mutations and amino acid substitutions in CA to inhibit restriction of a wild type HIV-1 reporter virus in owl monkey cells. The results demonstrated that a stable, polymeric capsid and a correctly folded amino-terminal CA subunit interface are essential for saturation of host restriction in target cells by HIV-1 cores. We conclude that the owl monkey cellular restriction machinery recognizes a polymeric array of CA molecules, most likely via direct engagement of the HIV-1 capsid in target cells prior to uncoating.

Animals↗
PubMed2006

The structure of H5N1 avian influenza neuraminidase suggests new opportunities for drug design.

The worldwide spread of H5N1 avian influenza has raised concerns that this virus might acquire the ability to pass readily among humans and cause a pandemic. Two anti-influenza drugs currently being used to treat infected patients are oseltamivir (Tamiflu) and zanamivir (Relenza), both of which target the neuraminidase enzyme of the virus. Reports of the emergence of drug resistance make the development of new anti-influenza molecules a priority. Neuraminidases from influenza type A viruses form two genetically distinct groups: group-1 contains the N1 neuraminidase of the H5N1 avian virus and group-2 contains the N2 and N9 enzymes used for the structure-based design of current drugs. Here we show by X-ray crystallography that these two groups are structurally distinct. Group-1 neuraminidases contain a cavity adjacent to their active sites that closes on ligand binding. Our analysis suggests that it may be possible to exploit the size and location of the group-1 cavity to develop new anti-influenza drugs.

Acetamides↗
PubMed2002

GM-CSF and M-CSF modulate beta-chemokine and HIV-1 expression in microglia.

Significant numbers of patients with acquired immunodeficiency syndrome (AIDS) develop CNS infection primarily in macrophages and microglial cells. Therefore, the regulation of human immunodeficiency virus type 1 (HIV-1) infection and activation of the brain mononuclear phagocytes subsequent to infection are important areas of investigation. In the current report, we studied the role of granulocyte-macrophage colony-stimulating factor (GM-CSF) and macrophage-CSF (M-CSF) in the expression of antiviral beta-chemokines and HIV-1 p24 in cultures of primary human fetal microglia. We found that stimulation with GM-CSF or M-CSF induced macrophage inflammatory proteins (MIP-1alpha and MIP-1beta) and augmented RANTES expression, after HIV-1 infection of microglia. This was not due to the effect of GM-CSF on viral expression because GM-CSF was neither necessary nor stimulatory for viral infection, nor did GM-CSF enhance the expression of env-pseudotyped reporter viruses. Blocking GM-CSF-induced microglial proliferation by nocodazole had no effect on beta-chemokine or p24 expression. The functional significance of the GM-CSF-induced beta-chemokines was suggested by the finding that, in the presence of GM-CSF, exogenous beta-chemokines lost their anti-HIV-1 effects. We further show that although HIV-1-infected microglia produced M-CSF, they failed to produce GM-CSF. In vivo, GM-CSF expression was localized to activated astrocytes and some inflammatory cells in HIV-1 encephalitis, suggesting paracrine activation of microglia through GM-CSF. Our results demonstrate a complex interplay between CSFs, chemokines, and virus in microglial cells and may have bearing on the interpretation of data derived in vivo and in vitro.

AIDS Dementia Complex↗
PubMed1996

Development of a replication-deficient recombinant vaccinia virus vaccine effective against parainfluenza virus 3 infection in an animal model.

The highly attenuated, replication-deficient, modified vaccinia virus Ankara (MVA) was used to express the fusion (F) and/or hemagglutinin-neuraminidase (HN) glycoproteins of parainfluenza virus 3 (PIV3). Initial recombinant viruses in which the HN gene was regulated by a very strong synthetic earlyllate promoter replicated poorly in permissive chick embryo cells evidently due to toxic levels of the gene product. This result led us to construct and evaluate a modified earlyllate promoter derived from the H5 gene of vaccinia virus. Reporter gene experiments indicated that the enhanced H5 promoter was about five times stronger than the 7.5 promoter used in previous recombinant vaccinia/ PIV3 viruses. Although the overall expression from the modified H5 promoter was less than that of the strong synthetic promoter, early expression, determined in the presence of an inhibitor of DNA replication, was higher. Importantly, recombinant MVA employing the modified H5 promoter to regulate the F or HN gene of PIV3 replicated to high titers in chick cells and expressed functional F or HN proteins as measured by syncytial formation upon dual infection of mammalian cells. Cotton rats inoculated with recombinant MVA expressing F or HN by intramuscular or intranasal routes produced high levels of antibody. The virus expressing HN, however, was the more effective of the two in inducing immunity to PIV3 challenge, reducing PIV3 viral titers in the nasal turbinates by at least 4.7 logs and in the lungs by 3.4 logs, similar to that achieved by immunization with PIV3. These studies support further testing of recombinant MVA/PIV3 viruses as safe and effective candidate vaccines.

Animals↗