Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “MICROCOCCAL INFECTIONS”

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 955 records · Page 53Linked to original sources
PubMed1976

Polyadenylate sequences of human rhinovirus and poliovirus RNA and cordycepin sensitivity of virus replication.

The polyadenylate [poly(A)] content of the genome RNA of human rhinovirus type 14 (HRV-14) is nearly twice as large as that of the genome RNA of poliovirus type 2. The poly(A) content of viral RNA was determined to be the RNase-resistant fraction of 32P-labeled viral RNA extracted from purified virions. Polyacrylamide gel electrophoresis indicated that the poly(A) sequences of HRV-14 are more heterogenous and on an average larger than those of poliovirus RNA. On the basis of susceptibility to micrococcal polynucleotide phosphorylase the rhinovirus genome terminates in poly(A). Replication of both viruses is almost totally inhibited by cordycepin at 50 mug/ml. At lower concentrations, rhinovirus replication is more sensitive to cordycepin than poliovirus replication. Addition of cordycepin (75 mug/ml) to infected culture prior to or during viral RNA replication results in more or less complete inhibition of virus-specific RNA synthesis. The results do not indicate that cordycepin sensitivity of either virus is due to preferential inhibition of viral poly(A) synthesis by this antibiotic.

Base Sequence↗
PubMed1995

Titration of serine/arginine (SR) splicing factors during adenoviral infection modulates E1A pre-mRNA alternative splicing.

Alternative splicing of the adenovirus-2 E1A pre-mRNA involves the use of three 5' splice sites and is modulated during infection because the 13S mRNA and 9S mRNA reactions are predominant during the early and late periods, respectively. We had previously reproduced in vitro the 13S to 9S modulation with nuclear extracts isolated from infected HeLa cells and shown that high molecular weight viral RNAs are involved in this modulation, most likely by sequestering or titrating general splicing factors. To further test this hypothesis, we titrated splicing factors from an uninfected nuclear extract using competitor RNA or by progressive inactivation of splicing factors with monoclonal antibodies. We found that the 13S to 9S modulation occurs when titrating only with certain RNAs (essentially adenoviral RNAs), and also by progressively inactivating the 9G8 SR splicing factor. The demonstration that late nuclear extracts contain levels of active SR splicing factors limiting for the 13S reaction has been made by complementation experiments. We show that late nuclear extracts do not complement SR factor-deficient extracts, whereas late extracts treated with micrococcal nuclease complement them. Furthermore, complementation of late nuclear extracts with each of the three 30-35-kDa SR factors (9G8, SC35, and SF2/ASF) restores an efficient 13S mRNA reaction. Thus, our results provide evidence that the 13S to 9S modulation is triggered through a titration of SR factors required for the 13S mRNA reaction by major late transcripts that accumulate in nuclei late in infection.

Adenoviridae↗
PubMed1982

Expression of vaccinia virus early mRNA in Ehrlich ascites tumor cells. 1. Translation of cellular and viral early mRNA in cell-free systems from uninfected and virus-infected cells at the early stage.

Translation of cellular and early vaccinia RNA in nuclease-treated lysates, derived from uninfected and vaccinia-virus-infected cells at the early stage, has been investigated. When using limiting amounts of RNA no discrimination of translation was observed in the infected cells lysates; this conclusion was confirmed by sensitive RNA competition experiments for translation in vitro and also when using two different fractionated systems for protein synthesis in vitro. This absence of detectable discrimination in vitro was established both by comparing incorporation of [35S]methionine into proteins and by analysis of the products thus synthesized by sodium dodecylsulfate gel electrophoresis. However, a modification of the translational machinery from vaccinia-virus-infected cells did occur since the only the ribosomal salt wash derived from infected cells was able to reverse the inhibition of protein synthesis in vitro resulting from excess RNA (control or early). This property of vaccinia-virus-infected cell lysates may result from the synthesis l machinery from vaccinia-virus-infected cells did occur since the only the ribosomal salt wash derived from infected cells was able to reverse the inhibition of protein synthesis in vitro resulting from excess RNA (control or early). This property of vaccinia-virus-infected cell lysates may result from the synthesis l machinery from vaccinia-virus-infected cells did occur since the only the ribosomal salt wash derived from infected cells was able to reverse the inhibition of protein synthesis in vitro resulting from excess RNA (control or early). This property of vaccinia-virus-infected cell lysates may result from the synthesis of an early protein involved in translation or from a better recovery of translational factors from the infected cells, as suggested in the accompanying paper.

Animals↗
PubMed1970

Enterotoxigenicity of Staphylococcus aureus cultures isolated from acute cases of bovine mastitis.

To determine whether staphylococci causing bovine mastitis are potential causes of human intoxications, 142 cultures identified as etiological agents of acute cases and 18 cultures causing chronic cases of staphylococcal mastitis were obtained from investigators in the United States and Canada, examined microscopically, and tested for carbohydrate utilization, terminal pH, catalase, coagulase, egg yolk hydrolysis, gelatin hydrolysis, cytochrome oxidase, urease production, nitrate reduction, micrococcal nuclease, phage type, and enterotoxin production. Three cultures were not confirmed as Staphylococcus aureus. Of the 157 S. aureus cultures, 23 produced staphylococcal enterotoxins. Although a direct relationship between staphylococcal mastitis and outbreaks of staphylococcal food poisoning was not proved, results indicated that staphylococcal infections of the bovine mammary gland represent a significant reservoir of enterotoxigenic strains of S. aureus.

Animals↗
PubMed1991

A rapid method for screening vaccinia virus recombinants.

A rapid and small-scale method for screening vaccinia virus recombinants employing micrococcal nuclease is described. This protocol utilizes the differential sensitivity of cellular and viral DNA to the nuclease, which can be selectively activated by addition of Ca2+ and inactivated by elimination of Ca2+. Two to five micrograms of viral DNA can be obtained from one infected L cell plate (50 mm) after overnight incubation.

Animals↗
PubMed1976

Subunit structure of simian-virus-40 minichromosome.

Electron microscopic evidence indicates that Simian virus 40 (SV40) minichromosomes extracted from infected cells consist of 20 +/- 2 nucleosomes, each containing 190 -- 200 base pairs of DNA. About 50% of the nucleosomes are not close together, but connected by segments of DNA of irregular lengths which correspond to about 15% of the viral genome, irrespective of the ionic strength. Micrococcal nuclease digestion studies show that there is about 200 base pairs of DNA in the biochemical unit of SV40 chromatin. Therefore, the visible internucleosomal DNA of the SV40 minichromosome does not arise from an unfolding of a fraction of the 190 - 200 base pairs of DNA initially wound in the nucleosome. These results support the chromatin model which proposes that the same DNA length is contained in the nucleosome and the biochemical unit. Results from extensive micrococcal nuclease digestion suggest that an SV40 nucleosome consists of a 'core' containing a DNA segment of about 135 base pairs associated to a DNA fragment more susceptible to nuclease attack. The addition of histone H1 results in a striking condensation of the SV40 minichromosome, which supports the assumption that histone H1 is involved in the folding of chromatin fibers.

Animals↗
PubMed1981

In vitro translation of Uukuniemi virus-specific RNAs: identification of a nonstructural protein and a precursor to the membrane glycoproteins.

We isolated the virus-specific RNA species from Uukuniemi virus-infected chicken embryo cells and fractionated them by sucrose gradient centrifugation. In addition to three RNA species cosedimenting with the three viral RNA segments L (29S), M (23S), and S (17S), a fourth major RNA species, sedimenting at about 12S (S2), was found early in the infection. Annealing experiments indicated that the cytoplasmic L and M RNA species consisted of both plus and minus strands, with the plus strands in slight excess. Most of the S1 RNA was of negative polarity, whereas S2 was of positive polarity. The S2 RNA specifically annealed to the virion S RNA segment, indicating that it is transcribed from this segment. In vitro translation of the individual RNA species in micrococcal nuclease-treated cell-free reticulocyte extracts showed that an mRNA cosedimenting with the virion M RNA directed the synthesis of a virus-specific 110,000-dalton polypeptide (p110). This polypeptide could be immunoprecipitated with antiserum prepared against purified virions. When translation was carried out in the presence of dog pancreas microsomes, p110 was absent. Instead, an immunoprecipitable polypeptide band, with a molecular weight of about 70,000 and migrating between the virion surface glycoproteins G1 and G2, was observed. It is thus likely that the glycoproteins are synthesized as a precursor (p110), which during translation is cleaved roughly in the middle to yield G1 and G2. The 12S RNA species directed the synthesis of the nucleocapsid protein and a novel polypeptide with an apparent molecular weight of about 30,000. The latter was not precipitated with antivirion serum and was absent from lysates programmed with the corresponding RNA fraction from a mock-infected extract. Since, in addition, it was not found in purified virions and was present in the cytoplasm of infected cells but not in uninfected cells, it probably represents a nonstructural polypeptide.

Animals↗
PubMed1994

Phage display of catalytically active staphylococcal nuclease.

Staphylococcal nuclease (SNase), a 14 kD enzyme that catalyzes the hydrolysis of single- and double-stranded nucleic acid, was fused to the N-terminus of the gene III (pIII) protein of filamentous phage fdtet. The SNase-pIII protein is infective and the catalyzes DNA hydrolysis, demonstrating that functional SNase can be displayed on the phage surface.

Bacteriophages↗
PubMed1982

Identification of adenovirus 2 early region 4 polypeptides by in vitro translation and tryptic peptide map analysis.

The mRNA species encoded by early region 4 (E4) (map position [mp] 91.5 to 99.3) of adenovirus 2 were isolated from the polysomes of infected KB cells and were purified by hybridization to the cloned HindIII-F fragment (mp 89.5 to 97.3) or to EcoRI-C fragment (mp 89.7 to 100). The mRNA's were translated in vitro using [35S]methionine as a labeled precursor in rabbit reticulocyte lysates treated with micrococcal nuclease as well as in wheat germ lysates. Five major (35,000-molecular-weight [35K], 23K, 22K, 21K, 18K) polypeptides were observed when the reticulocyte lysate was used. The 23K, 22K, 21K, and 18K polypeptides were also observed with the wheat germ lysate, as well as a very prominent 11K polypeptide; the 35K polypeptide was not observed. Assignment of these polypeptides to E4 was further established by hybrid arrested translation. Two-dimensional gel electrophoresis of a wheat germ translate resolved five polypeptides ranging from 18K to 23K, the major 11K polypeptide, and polypeptides of 10K and 9K. The in vitro 23K to 18K and 11K polypeptides migrated to approximately the same positions on two-dimensional gels as did seven 26K to 21K polypeptides and an 11K polypeptide synthesized in vivo (Brackmann et al., J. Biol. Chem, 255:6772--6779, 1980). Two-dimensional tryptic peptide maps demonstrated that the 35K, 23K, 22K, 21K, and 18K polypeptides are related. The peptide map of 11K is different from those of the above polypeptides, although 11K may share one tryptic methionine polypeptide with them. These results indicate that E4 encodes a major 11K polypeptide, as well as major 35K, 23K, 22K, 21K, and 18K polypeptides.

Adenoviruses, Human↗
PubMed2004

Development of cell lines stably expressing staphylococcal nuclease fused to dengue 2 virus capsid protein for CTVI.

To explore the potential application of capsid-targeted viral inactivation (CTVI) strategy in prophylactic model against dengue virus (DV) infection, here we fused a Ca(2+)-dependent nuclease, staphylococcal nuclease (SN), to the capsid protein of dengue 2 virus (D2C) at the carboxyl terminal, and constructed the desired expression plasmid pc/D2C-SN and control plasmids pc/D2C-SN* and pc/D2C. A mammalian cell line BHK-21 was transfected by electroporation with those plasmids and thereafter selected by 5mgr;/ml blasticidin. The resistant cell clones were then expanding cultured and screened by RT-PCR and Western Blot assays. The nuclease activity of the expressed fusion protein D2C-SN was analyzed by in vitro DNA digestion assay. It was confirmed cell lines stably expressing D2C-SN and control constructs were obtained. The intracellular expressed fusion protein D2C-SN had ideal nuclease activity and no cytotoxicity on mammalian cells. Those engineered cell lines provided the experimental system for CTVI application in prophylactic model and paved the new road for combating DV infection with CTVI.

Amino Acid Sequence↗
PubMed2003

Development and validation of a molecular beacon probe-based real-time polymerase chain reaction assay for rapid detection of methicillin resistance in Staphylococcus aureus.

CONTEXT: A rapid, real-time, duplex, fluorescent molecular beacon probe-based polymerase chain reaction (PCR) assay was recently developed for the detection of methicillin-resistant Staphylococcus aureus. OBJECTIVE: To describe the development and validation of this unique assay. DESIGN: Prospective laboratory analysis. SETTING: Urban health region/centralized diagnostic microbiology laboratory. BACTERIAL STRAINS: One hundred eighty-one previously characterized clinical and American Type Culture Collection isolates, including 50 strains each of methicillin-resistant and methicillin-sensitive S aureus, plus 50 strains of coagulase-negative staphylococci and 31 nonstaphylococcal isolates to ensure assay specificity. INTERVENTION: Assays were performed on purified genomic DNA extracted from growing bacterial colonies. Two sets of oligonucleotide primers were used to specifically amplify the mecA and nuc genes, followed by detection of amplicons using fluorophore-labeled molecular beacon probes. Assays were performed on the Mx4000 Multiplex Quantitative PCR System (Stratagene Inc, La Jolla, Calif). MAIN OUTCOME MEASURES: (1) Assay sensitivity and specificity, and (2) analytical sensitivity. RESULTS: The assay demonstrated 100% sensitivity and 100% specificity, and accurately characterized isolates as methicillin-resistant S aureus, methicillin-sensitive S aureus, or methicillin-resistant coagulase-negative staphylococci, with test results available in 2.5 hours. The analytical sensitivity of the assay was determined to be between 6 and 60 genomic equivalents. CONCLUSIONS: This assay is rapid, accurate, easy to perform, and is compatible with other real-time PCR instruments, making it a suitable alternative to conventional PCR methodologies.

Bacterial Proteins↗
PubMed1993

Partial purification and characterization of foxtail mosaic potexvirus RNA-dependent RNA polymerase.

The RNA-dependent RNA polymerase (RdRp) of foxtail mosaic virus (FMV) was partially purified from infected leaves of Chenopodium quinoa. The membrane fraction of crude plant extracts contained most of the FMV RdRp activity. Additional purification was obtained by solubilization of the RdRp using KCl and dodecyl-sucrose and by centrifugation through a glycerol gradient. The RNA template endogenous to RdRp preparations could be removed using micrococcal nuclease but the resulting fraction was unable to copy added template purified from FMV virions. However, supplementation of fractions containing RdRp activity with FMV RNA resulted in a significant decrease in the level of RNA synthesis. This effect was specific to potexviral RNAs since a similar interference was also observed with clover yellow mosaic virus RNA but not with brome mosaic virus RNA or yeast RNA. RNA transcripts corresponding to various regions of the FMV genome were tested for their ability to inhibit RNA synthesis on endogenous template. The simultaneous presence of both 5' and 3' terminal regions of the viral genome was necessary to interfere with RNA synthesis suggesting that this inhibition resulted from competition for the binding of component(s) of the RdRp complex.

Base Sequence↗
PubMed1980

Structure, spacing, and phasing of nucleosomes on isolated forms of mature simian virus 40 chromosomes.

Mature Simian virus 40 (SV40) chromosomes were isolated from infected CV-1 monkey cells by a hypotonic extraction method that not only allowed replicating viral chromosomes to faithfully continue DNA replication in vitro, but also was found to assemble nascent DNA into nucleosomes with a structure and arrangement typical of native viral chromosomes. Detailed analysis of the DNA and nucleoprotein products from micrococcal nuclease and DNase I digestion of mature viral chromosomes assembled in intact cells showed that the structure of SV40 and CV-1 cellular nucleosomes was the same. Furthermore, the histone composition of viral chromosome was indistinguishable from that of its host. In contrast to the identity in nucleosome structure, nucleosome spacing on isolated SV40 chromosomes was not as regular as on cellular chromatin. When 1% of the DNA was solubilized by micrococcal nuclease, as many as 20 cellular DNA bands were clearly resolved by gel electrophoresis, but only 6 to 7 viral DNA bands were observed and they were broader and less well resolved. In addition, micrococcal nuclease digested SV40 chromosomes at a faster initial rate and to a greater extent than CV-1 chromatin present in the same tube. Either BglI or EcoRI restriction endonuclease cut a single site in 30% of the SV40 chromosomes which suggested that viral nucleosomes were not located in a unique phase with respect to DNA sequence, but appeared to be randomly spaced around the genome. Viral chromosome structure was basically unaltered in hypotonically extracted chromosomes exposed to 200 or 600 mM NaCl and in isotonically extracted chromosomes prepared in the presence of Triton X-100 and EDTA. These results confirm and extend our previous data on the arrangement of SV40 nucleosomes inside isolated nuclei and demonstrate that the structure of viral chromosomes was not altered by the isolation procedures employed. The data are consistent with a model in which an average of 22 nucleosomes, randomly distributed around the SV40 genome, are separated by non-nucleosomal spacer regions which account for about 20% of the total DNA.

Animals↗