Detection of viruses and body fluids which may contain viruses in the domestic environment.
(9/25126)
The domestic environment was investigated for the presence of viruses and body fluids that may contain viruses. A range of surfaces in 39 homes (17 visited on 2 occasions) were sampled by swabbing and analysed using cell culture, reverse transcription polymerase chain reaction for enteroviral RNA, haemoglobin as a marker for blood, amylase as an indicator of urine, saliva and sweat, and protein as an indicator of general hygiene. Haemoglobin was found on 1.9% of surfaces sampled and of the positive samples 30% were from articles frequently handled. Amylase (> 5 U/l) was found in 29.3% of samples tested. Protein was found in 97.8% of samples tested. Enteroviral RNA, indicating the presence of virus, was detected in 3 out of 448 samples tested; they were from a tap handle, telephone handpiece and a toilet bowl. No viruses were isolated in cell culture, however significant problems were encountered with bacterial and fungal contamination. This work demonstrates that only testing environmental samples for bacteria and ATP may not give a total view of the microbiological problem in the home. A range of test methods is useful to gain a broad view of the problems of hygiene in the home and to allow comparative studies of specific areas such as the kitchen and bathroom. (+info)
Inhibition of Echovirus-12 multiplication by N-carbobenzoxy-D-glucosamine.
(10/25126)
The glucosamine derivative, N-carbobenzoxy-D-glucosamine (NCBZG) inhibits the multiplication of Echovirus-12 and the synthesis of both virus RNA and protein at a stage in the virus growth cycle after attachment and penetration. However, the compound does not inhibit virus multiplication after the appearance of progeny virus nor after virus RNA has accumulated. Incorporation of radioactive glucosamine and choline into infected and uninfected cultures is inhibited by NCBZG as is the virus-induced increase in choline incorporation. The compound also prevents the appearance of radioactive choline in isolated membranous structures. The compound did not alter significantly the cellular RNA or protein synthesis, plating efficiency of the cells, their growth over a period of several days, nor the virus-directed inhibition of cellular RNA and protein. These findings suggest that the compound inhibits virus multiplication by its effect on the initiation of biosynthesis which appears to require membrane synthesis. (+info)
Synthesis of bacteriophage phi6 double-stranded ribonucleic acid.
(11/25126)
Uracil was incorporated into all three bacteriophage phi6 dsRNA segments throughout the infection cycle; the rates of incorporation into each of the three segments were approx. constant for the first 15 to 20 min and then increased rapidly until 50 min after infection. The medium and small dsRNA segments were produced in greater amounts than the large dsRNA segment at all times in the infection cycle. Inhibition of host RNA and protein synthesis with rifampin and chloramphenicol revealed that virus dsRNA synthesis immediately after infection was independent of either host function. (+info)
Cervicovaginal human papillomavirus infection in human immunodeficiency virus-1 (HIV)-positive and high-risk HIV-negative women.
(12/25126)
BACKGROUND: Human papillomavirus (HPV) infection is associated with precancerous cervical squamous intraepithelial lesions commonly seen among women infected with human immunodeficiency virus-1 (HIV). We characterized HPV infection in a large cohort of HIV-positive and HIV-negative women participating in the Women's Interagency HIV Study to determine the prevalence of and risk factors for cervicovaginal HPV infection in HIV-positive women. METHODS: HIV-positive (n = 1778) and HIV-negative (n = 500) women were tested at enrollment for the presence of HPV DNA in a cervicovaginal lavage specimen. Blood samples were tested for HIV antibody status, level of CD4-positive T cells, and HIV RNA load (copies/mL). An interview detailing risk factors was conducted. Univariate and multivariate analyses were performed. RESULTS: Compared with HIV-negative women, HIV-positive women with a CD4+ cell count of less than 200/mm3 were at the highest risk of HPV infection, regardless of HIV RNA load (odds ratio [OR] = 10.13; 95% confidence interval [CI] = 7.32-14.04), followed by women with a CD4+ count greater than 200/mm3 and an HIV RNA load greater than 20,000 copies/mL (OR = 5.78; 95% CI = 4.17-8.08) and women with a CD4+ count greater than 200/mm3 and an HIV RNA load less than 20,000 copies/mL (OR = 3.12; 95% CI = 2.36-4.12), after adjustment for other factors. Other risk factors among HIV-positive women included racial/ethnic background (African-American versus Caucasian, OR = 1.64; 95% CI = 1.19-2.28), current smoking (yes versus no; OR = 1.55; 95% CI = 1.20-1.99), and younger age (age < 30 years versus > or = 40 years; OR = 1.75; 95% CI = 1.23-2.49). CONCLUSIONS: Although the strongest risk factors of HPV infection among HIV-positive women were indicators of more advanced HIV-related disease, other factors commonly found in studies of HIV-negative women, including racial/ethnic background, current smoking, and age, were important in HIV-positive women as well. (+info)
hnRNP C and polypyrimidine tract-binding protein specifically interact with the pyrimidine-rich region within the 3'NTR of the HCV RNA genome.
(13/25126)
Like other members of the Flaviviridae family, the 3' non-translated region (NTR) of the hepatitis C virus (HCV) is believed to function in the initiation and regulation of viral RNA replication by interacting with components of the viral replicase complex. To inves-tigate the possibility that host components may also participate in this process, we used UV cross-linking assays to determine if any cellular proteins could bind specifically to the 3'NTR RNA. We demonstrate the specific interaction of two host proteins with the extensive pyrimidine-rich region within the HCV 3'NTR. One host protein migrates as a doublet with a molecular weight of 57 kDa and is immunoreactive with antisera specific for polypyrimidine tract-binding protein (PTB), and the other protein (35 kDa) is recognized by a monoclonal antibody specific for heterogeneous nuclear ribonucleoprotein C (hnRNP C). These results suggest that recognition of the large pyrimidine-rich region by PTB and hnRNP C may play a role in the initiation and/or regulation of HCV RNA replication. (+info)
Mutational analysis of the antigenomic trans-acting delta ribozyme: the alterations of the middle nucleotides located on the P1 stem.
(14/25126)
Our previous report on delta ribozyme cleavage using a trans -acting antigenomic delta ribozyme and a collection of short substrates showed that the middle nucleotides of the P1 stem, the substrate binding site, are essential for the cleavage activity. Here we have further investigated the effect of alterations in the P1 stem on the kinetic and thermodynamic parameters of delta ribozyme cleavage using various ribozyme variants carrying single base mutations at putative positions reported. The kinetic and thermodynamic values obtained in mutational studies of the two middle nucleotides of the P1 stem suggest that the binding and active sites of the delta ribozyme are uniquely formed. Firstly, the substrate and the ribozyme are engaged in the formation of a helix, known as the P1 stem, which may contain a weak hydrogen bond(s) or a bulge. Secondly, a tertiary interaction involving the base moieties in the middle of the P1 stem likely plays a role in defining the chemical environment. As a con-sequence, the active site might form simultaneously or subsequently to the binding site during later steps of the pathway. (+info)
unr, a cellular cytoplasmic RNA-binding protein with five cold-shock domains, is required for internal initiation of translation of human rhinovirus RNA.
(15/25126)
Initiation of translation of the animal picornavirus RNAs occurs via a mechanism of direct ribosome entry, which requires a segment of the 5' UTR of the RNA, known as the internal ribosome entry site (IRES). In addition, translation of the enterovirus and rhinovirus (HRV) subgroups requires cellular trans-acting factors that are absent from, or limiting in rabbit reticulocytes, but are more abundant in HeLa cell extracts. It has been shown previously that HeLa cells contain two separable activities, each of which independently stimulates HRV IRES-dependent translation when used to supplement reticulocyte lysate; one of these activities was identified as polypyrimidine tract-binding protein (PTB). Here, the purification of the second activity is achieved by use of an RNA-affinity column based on the HRV 5' UTR. It comprises two components: a 38-kD protein (p38), which is a novel member of the GH-WD repeat protein family and has no intrinsic RNA-binding activity; and a 96- to 97-kD protein doublet, which was identified as unr, an RNA-binding protein with five cold-shock domains. Coimmunoprecipitation with antibodies against either protein shows that the two proteins interact with each other, and thus p38 is named unrip (unr-interacting protein). Recombinant unr acts synergistically with recombinant PTB to stimulate translation dependent on the rhinovirus IRES. In contrast, unr did not significantly augment the PTB-dependent stimulation of poliovirus IRES activity. (+info)
The cleavable carboxyl-terminus of the small coat protein of cowpea mosaic virus is involved in RNA encapsidation.
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The site of cleavage of the small coat protein of cowpea mosaic virus has been precisely mapped and the proteolysis has been shown to result in the loss of 24 amino acids from the carboxyl-terminus of the protein. A series of premature termination and deletion mutants was constructed to investigate the role or roles of these carboxyl-terminal amino acids in the viral replication cycle. Mutants containing premature termination codons at or downstream of the cleavage site were viable but reverted to wild-type after a single passage through cowpea plants, indicating that the carboxyl-terminal amino acids are important. Mutants with the equivalent deletions were genetically stable and shown to be debilitated with respect to virus accumulation. The specific infectivity of preparations of a deletion mutant (DM4) lacking all 24 amino acids was 6-fold less than that of a wild-type preparation. This was shown to be a result of DM4 preparations containing a much increased percentage (73%) of empty (RNA-free) particles, a finding that implicates the cleavable carboxyl-terminal residues in the packaging of the virion RNAs. (+info)