Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.27.5 (RNase)
 17,967 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Several virion and nonvirion DNAs were tested for the ability to activate endogenous type C virus in BALB/c-derived mouse cells using the calcium precipitation technique. The DNAs from all herpesviruses tested activated xenotropic type C virus synthesis. These included DNAs from herpes simplex virus types 1 and 2, Epstein-Barr virus, human cytomegalovirus, SA8 virus, infectious bovine rhinotracheitis virus, pseudorabies virus, and herpes saimiri virus (M-DNA). In contrast, DNAs from vaccinia virus, simian virus 40, primate cells, bacteria, mycoplasma, and salmon sperm showed no ability to activate type C virus when tested under the same conditions. Several herpesviruses and vaccinia virus, which were highly infectious for the BALB/c cells used, were tested for their ability to activate type C virus after UV irradiation. All herpesviruses tested were positive, while vaccinia virus was negative. Unirradiated simian virus 40 also showed no ability to activate type C virus. Activation of type C virus by DNA from herpes simplex virus was observed after shearing or sonication of the DNA to an average size of 3 x 10(6) daltons, but was not observed with DNA sonicated to an average size of 1 x 10(6) daltons. Alkali denaturation of DNA from herpes simplex virus or treatment with DNase, but not RNase, destroyed its ability to activate type C virus, as did crosslinking of the DNA with 4,5',8-trimethylpsoralen (psoralen) and light.
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PMID:Activation of endogenous type C virus in BALB/c mouse cells by herpesvirus DNA. 21 61

The localization of some enzymic activities in cell fractions of Ureaplasma urealyticum was studied. A quantitative evaluation of the effectiveness of several cell lysis procedures was obtained by using labeled membranes and sucrose density gradient centrifugation. Ultrasonic treatment was found to be the most effective procedure for lysing the cells, whereas digitonin and osmotic shock caused the lysis of only 70 and 50% of the cells, respectively. The localization of selected enzymes in Ureaplasma cells resembled that found in other Mycoplasma species. Adenosine triphosphatase, ribonuclease, deoxyribonuclease, and p-nitrophenylphosphatase activities were located exclusively in the membrane fraction, whereas urease and L-histidine ammonia-lyase were located in the cytoplasm.
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PMID:Cell fractions and enzymatic activities of Ureaplasma urealyticum. 21 22

We have investigated the pathogenesis of the polyclonal hypogammaglobulinemia associated with BALB/c plasmacytomas TEPC-183 and SPQC-11 to gain insight into the hypogammaglobulinemia observed in human myeloma. With pokeweed mitogen-driven IgM biosynthesis by mouse splenocytes as the indicator system for suppression, we found that a protein extract of asscites cells obtained from these tumor-bearing animals could suppress immunoglobulin production, whereas like extracts from a non-suppressing plasmacytoma, modified RPC-5, caused no suppression in vitro. Extracts of tumor ascites depleted of mononuclear phagocytes by iron carbonyl treatment showed little suppressor activity. The active extract was not cytotoxic and contained no mycoplasma or common murine viruses. Furthermore, the active suppressor factor appears to be a low m.w. protein that is not affected by treatment with ribonuclease. These results and others are consistent with the idea that the hypogammaglobulinemia of myeloma is due to the formation of immunoregulatory macrophage-like cells which synthesize a suppressor substance.
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PMID:Hypogammaglobulinemia in experimental myeloma: the role of suppressor factors from mononuclear phagocytes. 85 68

Folded chromosomes were isolated from Mycoplasma hyorhinis. When examined by electron microscopy, these molecules show variability of loop size, number of loops, total contour length and degree of twisting of the DNA. Sedimentation velocity was unaltered after treatment with RNase, proteinase K, SDS, temperatures up to 65 degrees C and NaCl concentrations from 0.1 M to 4 M.
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PMID:Isolation of folded chromosomes from Mycoplasma hyorhinis. 89 68

A protein homologous to SRP54, a subunit of the mammalian signal recognition particle (SRP), was identified in Mycoplasma mycoides. The mycoplasma protein was expressed in E.coli and purified to near homogeneity. It was shown to bind specifically in vitro to a small mycoplasma RNA with structural features related to the RNA component of SRP. These findings provide evidence of a ribonucleoprotein complex in mycoplasma reminiscent of SRP. A part of the RNA was protected from ribonuclease digestion in the presence of the SRP54 homologue. The protected region contains structural elements that have been highly conserved in SRP RNAs during evolution.
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PMID:A Mycoplasma protein homologous to mammalian SRP54 recognizes a highly conserved domain of SRP RNA. 128 Aug 9

Mycoplasmas (Mollicutes) constitute a constant threat as insidious contaminants of animal cell cultures. They are responsible for myriad biochemical reactions associated with the cells they infect, and undoubtedly have been the source of metabolic and physiological activities attributed to their hosts. In an attempt to demonstrate a dsRNA-inducible double-stranded ribonuclease (dsRNase) in mammalian cells, comparable to that reported in avian cells, we discovered high levels of dsRNase "induced" by a particular stock of vesicular stomatitis virus. We now report that the double-stranded ribonuclease resulted from the activity of a contaminant in that stock--a "noncultivable" Mycoplasma hyorhinis. This report demonstrates the ubiquitous distribution of dsRNase among mycoplasmas, presents some characteristics of the enzyme and its production, and implicates once again mycoplasmas as contaminants of cell culture and potential perturbers of cellular physiology.
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PMID:Mycoplasmas produce double-stranded ribonuclease. 216 46

A method is described for the rapid isolation of chromosomal deoxyribonucleic acid from species of the genus Mycoplasma. The method involves incubation of washed cells at elevated temperature in the presence of an ionic detergent, chelating agents, and proteinase K prior to the removal of residual protein and ribonucleic acid with ribonuclease and chloroform. It results in a good yield of high molecular weight material that is shown to be free of endogenous nuclease and substantially free of protein or ribonucleic acid contamination without the use of phenol. The isolated DNA is shown to be an excellent substrate for restriction endonuclease digestion and ligation with T4 DNA ligase.
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PMID:An improved method for the rapid isolation of chromosomal DNA from Mycoplasma spp. 218 71

A Mycoplasma fermentans-derived high-molecular-weight material (MDHM) is described which causes differentiation of concanavalin A-stimulated CBA/J or C57BL/6 mouse thymocytes to cytolytic effector T cells (CTLs). The effect of MDHM was inhibited by addition of monoclonal anti-interleukin-6 (IL-6) antibody. It could also be abolished after removal of adherent cells. However, adherent cell-depleted thymocytes could still form CTLs after addition of IL-6. The action of MDHM could thus be explained by the capacity of MDHM to stimulate IL-6 release from adherent cells. MDHM was active on macrophages from CBA/J and C3H/HeJ endotoxin nonresponder mice and was also capable of stimulating IL-6 release from human monocytes. On gel chromatography, MDHM had an apparent molecular size of 1.5 x 10(6) daltons. Treatment with RNase and DNase had no effect on either size or biological activity. Proteinase K did not abolish activity but reduced the apparent molecular size of MDHM. MDHM production by M. fermentans required either coculture with eucaryotic cell lines in RPMI 1640 medium with fetal calf serum or addition of eucaryotic cell sonic extracts to this medium. The biological activity of MDHM is not identical to that of a mitogen for murine spleen cells derived from M. arthritidis; MDHM caused only slight proliferation in this system compared with the mitogen from M. arthritidis, and the latter did not elicit IL-6 release from macrophages. The results are discussed in relation to mycoplasmas as putative etiological agents for rheumatoid arthritis, since high IL-6 titers were reported for synovial fluid from patients with this disease.
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PMID:Mycoplasma fermentans-derived high-molecular-weight material induces interleukin-6 release in cultures of murine macrophages and human monocytes. 232 16

Mycoplasma colonies and Mycoplasma cells in preparations from infected milk and lymph nodes were observed for their fluorescent qualities after treatment with acridine orange. Mycoplasma colonies fluoresced brilliant red or red-orange. When treated after exposure to ribonuclease, the colonies fluoresced lime-green. There was no fluorescence when both ribonucleic acid and deoxyribonucleic acid were destroyed by perchloric acid. Detection of Mycoplasma in smears of mastitic milk or smears of infected lymph nodes was not definitive because of the large amount of nonspecific ribonucleic acid-rich material present during inflammatory reactions.
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PMID:Histochemical observations on Mycoplasma after staining with acridine orange. 416 9

A Mycoplasma gallisepticum subcellular fraction (P2), which contains the deoxyribonucleic acid replication complex, can be isolated by differential centrifugation of freeze-thaw-lysed cells. The nascent deoxyribonucleic acid is released from P2 by Lubrol-WX, sodium dodecyl sulfate, Pronase, and deoxyribonuclease, but not by saponin, ribonuclease, phospholipase C, or high-frequency sonic treatment. Sonic treatment further fractionates the cell ghost and allows partial purification, on sucrose density gradients, of a deoxyribonucleic acid replication complex attached to the cells' polar membrane-bleb-infrableb structures.
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PMID:Partial purification of a membrane-associated deoxyribonucleic acid complex from Mycoplasma gallisepticum. 442 Sep 60


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