Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.1.26.9 (ribonuclease)
6,589 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Heat-labile enterotoxin (LT) produced by a human strain of enterotoxigenic Escherichia coli (286C(2)) was purified to homogeneity from pH extracts of fermentor-grown cells by ultrafiltration, (NH(4))(2)SO(4) fractionation, hydrophobic chromatography on norleucine-Sepharose 4B, hydroxylapatite chromatography, and Bio-Gel P-150 filtration. Purified LT preparations exhibited biological activity comparable to that of cholera toxin in four bioassays specific for the two enterotoxins (Y-1 adrenal tumor cells, Chinese hamster ovary cells, pigeon erythrocyte lysates, and skin permeability test). The overall yield of LT protein was 20%, which represented a 500-fold purification over pH extracts. A native molecular weight of 73,000 was determined by gel electrophoresis. The toxin dissociated upon treatment with sodium dodecyl sulfate, pH 7.0, into two components with molecular weights of 44,000 and 30,000. Purified LT preparations were remarkably stable over a wide range of storage conditions, temperatures, and pH's. The biological activity was increased by incubation with trypsin and completely destroyed by pronase and proteinase K, whereas deoxyribonuclease I, ribonuclease, and phospholipase D had no effect. The amino acid composition of purified LT was quite different from that of cholera toxin. Neither carbohydrate nor lipopolysaccharide was present in purified preparations. The purification scheme appeared applicable to LT produced by other human and porcine enterotoxigenic strains, but reflected the amount of LT produced by each strain. These data show that LT and cholera toxin share many common chemical and physical properties, but must be purified by different techniques.
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PMID:Purification and chemical characterization of the heat-labile enterotoxin produced by enterotoxigenic Escherichia coli. 3 93

An extract made from the supernatant of Neisseria gonorrhoeae Gc2 strain 1291 degraded the Gc2 polysaccharide antigen. Chemical analysis of this polysaccharide indicated it contains glucose, galactose, glucosamine, galactosamine, glucosamine-6-phosphate, heptose, 2-keto-3-deoxyotonate, and ethanolamine and is the polysaccharide component of gonococcal lipopolysaccharide. Degradation of the polysaccharide by sonic extracts resulted either in complete loss of antigenicity and immunogenicity or in partial degradation to subunits that could inhibit the Gc2-specific hemagglutination inhibition. The factors responsible for degradation were destroyed by heating at 100 degrees C for 5 min or by Pronase digestion, but were unaffected by ribonuclease, deoxyribonuclease, Mg2+, Ca2+, or ethylenediaminetetraacetic acid. The process was pH dependent, with optimal activity occurring at pH 7. Sonic extract supernatants from group B and C meningococcal strains contained degrading properties, whereas similar extracts produced from Escherichia coli, Staphylococcus aureus, Klebsiella pneumoniae, and Streptococcus pneumoniae type II failed to degrade the Gc2 polysaccharide.
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PMID:Degradation of the polysaccharide component of gonococcal lipopolysaccharide by gonococcal and meningococcal sonic extracts. 7 94

Antiserum to a purified type R lipopolysaccharide antigen isolated from Neisseria gonorrhoeae was used in a slide agglutination test and compared with conventional carbohydrate utilization and fluorescent antibody tests to confirm the identity of laboratory cultures classified as typical or "atypical" N. gonorrhoeae. Cultures of Corynebacterium vaginalis, N. meningitidis, N. catarrhalis, N. sicca, and N. lactamicus were also tested in the slide agglutination procedure. The addition of both deoxyribonuclease and ribonuclease (1 mg/ml) to the cell suspension medium of phosphate-buffered saline improved the sensitivity and specificity of the agglutination reaction for N. gonorrhoeae. Problems relating to the agglutination test as an aid in identification of N. gonorrhoeae are discussed.
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PMID:Nuclease enhancement of specific cell agglutination in a serodiagnostic test for Neisseria gonorrhoeae. 11 Aug 30

Membrane-defective mutants of Escherichia coli J5 were isolated on the basis of supersensitivity to the antibiotic novobiocin. These mutants display an increased sensitivity to a wide range of antibiotics and to several dyes and detergents. In addition, several mutants leak the periplasmic enzymes, alkyline phosphatase and ribonuclease. This evidence indicates an outer membrane defect in these mutants. The inner and outer membranes of one mutant were separated and subjected to compositional analysis. A deficiency in galactose containing lipopolysaccharide in the outer membrane of the mutant was observed. Two possible causes of this deficiency were examined and discounted: defective galactose uptake into the cell, and defective translocation of lipopolysaccharide from the inner membrane. Extraction and chemical analysis of mutant and wild type lipopolysaccharides suggests that the mutant is defective in the enzyme which transfers glucose to the growing lipopolysaccharide core, UDPglucose transferase. Thus, the mutant's deficiency in galactose-containing lipopolysaccharide can be ascribed to the fact that addition of glucose to the lipopolysaccharide core is a prerequisite for galactose addition. The physiological implications of this alteration are discussed.
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PMID:Biosynthesis and structure of lipopolysaccharide in an outer membrane-defective mutant of Escherichia coli J5. 32 11

Heat-stable enterotoxin (ST) produced by porcine strains of enterotoxigenic (ENT+) Escherichia coli has been purified to apparent homogeneity by sequential ultrafiltration, acetone fractionation, preparative gel electrophoresis, diethylaminoethyl Bio-Gel A ion-exchange chromatography, and Bio-Gel P-10 gel filtration. The enterotoxin, purified more than 1,500-fold, exhibited a molecular weight of 4,400, as determined by both sodium dodecyl sulfate-gel electrophoresis and gel filtration. A molecular weight of 5,100, representing 47 residues, was calculated from amino acid analysis data. The amino acid content was distinctive, with an unusually high proportion of cystines and few hydrophobic amino acids. A single amino-terminal residue, glycine, was observed. Purified ST was stable to heating (100 degrees C, 30 min) and did not lose biological activity after treatment with Pronase, trypsin, proteinase K, deoxyribonuclease, ribonuclease, and phospholipase C. Periodic acid oxidation and several organic solvents (acetone, phenol, chloroform, and methanol) had no effect on the biological activity of ST. Further, purified ST was stable to acid treatment at pH 1.0 but lost biological activity at pH values greater than 9.0. Neither lipopolysaccharide nor lipid contamination was evident in purified preparations. A characteristic absorption spectrum was observed during the course of the purification, which shifted from a maximum at 260 nm in crude preparations to 270 nm for the purified toxin. Antiserum obtained from rabbits immunized with ST or ST coupled to bovine serum albumin neutralized the action of the enterotoxin in suckling mice; however, passive hemagglutination and hemolysis titer assays suggested that ST is a poor antigen.
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PMID:Purification and chemical characterization of the heat-stable enterotoxin produced by porcine strains of enterotoxigenic Escherichia coli. 34 81

Ribosomal preparations from Neisseria gonorrhoeae types 1 and 4 were examined for their in vitro stimulation of mouse splenocytes to determine the ribosomal moiety or contaminant responsible for the immunoproliferative activity. In immunodiffusion tests with homologous rabbit antiserum, crude 70S ribosomes formed four precipitin bands while the purified 30S and 50S subunits showed one major line. The same antiserum reacted with lysed N. gonorrhoeae and Neisseria meningitidis A cells but no precipitation occurred with Escherichia coli cells purified N. gonorrhoeae lipopolysaccharide (LPS). No membrane or LPS contaminant was detected in the purified 30S and 50S preparations. All the ribosomal preparations from virulent and non-virulent N. gonorrhoeae consistently stimulated the murine splenocytes. The mitogenic activity of the 30S and 50S ribosomal preparation was destroyed by treatment with trypsin but only slightly decreased by ribonuclease. It is suggested that the lymphoproliferative response elicited by gonococcal ribosomes is triggered by the protein moiety of the 30S or 50S subunits.
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PMID:Characterization of the mitogenic activity elicited by Neisseria gonorrhoeae ribosomal fractions. 41 60

The cells of P. multocida strain P-1059 were destroyed with the French pressure cell; the ribosomal fraction proven to be homogeneous by analytical ultracentrifugation was obtained from the product by centrifugal fractionation, zonal electrophoresis, and Sephadex G-200 gel filtration. The ribosomal fraction exhibited intense protective antigenicity in mice and chickens, but the lipopolysaccharide (endotoxin) and the other bacterial cell fraction obtained in this experiment did not. Sodium deoxycholate treatment of the ribosomal fraction resulted in only a 13% loss in immunological activity, and ribonuclease treatment caused a 60% loss of activity.
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PMID:Immunogenic activity of a ribosomal fraction obtained from Pasteurella multocida. 83 95

The endotoxic activity of Fusobacterium necrophorum bov 5 was investigated. The supernatant (S) fluid and cell wall (CW) preparation, obtained after differential centrifugation of the ruptured cell mass, were lethal for mice. The toxicity of the S fluid was stable during prolonged storage, treatment with formalin, and heating for 15 minutes at 80, 100, and 121 C, but was destroyed by alkaline hydrolysis with 0.25 N NaOH. The toxic factor was found in a high molecular weight (MW) fraction after gel filtration. The properties exhibited by the toxic S fluid resembled those of endotoxic lipopolysaccharide (LPS). Extracted and partially purified LPS (endotoxin) from F necrophorum bov 5 demonstrated a mouse median lethal dose (mouse LD50) of 16.8 mg/kg of body weight. The toxic LPS material, a high molecular weight moiety as estimated by gel filtration, was resistant to ribonuclease (RNase), deoxyribonuclease (DNase), and pronase treatment. A positive Shwartzman reaction (median skin lesion dose (SLD50) equal to 3.32 mug/kg of body weight) and biphasic fever response (minimal dose required to produce a fever index of 40 sq cm which falls on the linear portion of dose-response curve (FL40) equal to 0.41 mug/kg of body weight) further indicated the toxin was endotoxin in nature. The LPS from F necrophorum bov 5 was less toxic than Salmonella typhimurium LPS; but had considerable toxicity for experimental animals. The toxic activity of the partially purified F necrophorum bov 5 endotoxin was separated into 2 fraction regions by diethylaminoethyl (DEAE)-cellulose chromatography. The data provide evidence for the production of a potent endotoxin, possibly composed of more than one toxic component, which may be released upon cell disruption.
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PMID:Endotoxin from Fusobacterium necrophorum of bovine hepatic abscess origin. 114 41

Transforming growth factor (TGF)-beta and interleukin (IL)-10 inhibited lipopolysaccharide (LPS)-induced macrophage production of the inflammatory cytokines tumor necrosis factor-alpha (TNF), IL-1 alpha, and IL-1 beta by contrasting post-transcriptional mechanisms. TGF-beta acted slowly and late, as it required 12-16 h to exert a suppressive effect, and inhibited TNF production even when added 6 h after LPS. TGF-beta affected neither the level of TNF mRNA, the release of preformed TNF nor the degradation of TNF. Thus, TGF-beta appeared to inhibit translation of TNF mRNA. IL-10 not only suppressed TNF release to a 25-fold greater extent than TGF-beta, but also inhibited release of IL-1. In contrast to TGF-beta, IL-10 acted on an early step in cytokine production, its effect being maximal 3 h after addition of LPS. Unlike TGF-beta, IL-10 markedly suppressed TNF, IL-1 alpha, and IL-1 beta mRNA levels. However, this was accomplished without suppressing transcription of the corresponding genes. Moreover, cycloheximide antagonized the IL-10-dependent reduction in cytokine mRNA levels. Thus, IL-10 may induce a ribonuclease active on cytokine transcripts or may induce a protein that enhances the susceptibility of TNF, IL-1 alpha, and IL-1 beta mRNAs to ribonucleolytic action. We conclude that IL-10 and TGF-beta induce different phenotypes of macrophage deactivation, and deactivate macrophages by different mechanisms: IL-10 promotes degradation of cytokine mRNA, while TGF-beta primarily suppresses translation.
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PMID:Contrasting mechanisms for suppression of macrophage cytokine release by transforming growth factor-beta and interleukin-10. 142 77

The strain-dependent expression of murine serum amyloid P-component (SAP) has been known to be linked to the Sap locus. We have quantified the SAP mRNA in several inbred strains including DBA/2 and C57BL/6 mice which represent high and low producers of SAP at resting state, respectively, and found that the mRNA levels correlated well with the amount of SAP protein. Interestingly, the SAP mRNA level of F1 mouse between DBA/2 and C57BL/6 was low and similar to that of C57BL/6. Primer extension and ribonuclease (RNAase) protection analyses demonstrated that a single type of transcript was generated from the SAP gene and that the cap sites were identical regardless mouse strains tested under unstimulated and stimulated (by lipopolysaccharide (LPS) or interleukin-6 (IL-6)) conditions. To investigate possible structural difference of the SAP gene including 5' flanking region, we have cloned, sequenced and compared the SAP genes from DBA/2 and C57BL/6 mice. Sequence analyses revealed that the 5' flanking regulatory regions, as well as the coding regions, were well-conserved between the two strains. These results demonstrate that the strain-dependent SAP expression occurs at the transcriptional level but seems to be affected by neither different type of the transcripts nor structural difference of the 5' flanking and coding regions of the SAP gene. It was suggested that a possible transcription factor with suppressive activity, which is encoded by a gene linked to Sap, may be involved.
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PMID:The strain-dependent constitutive expression of murine serum amyloid-P component is regulated at the transcriptional level. 162 42


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