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)

As part of a screening program for pseudomonad enzymes having an industrial interest, we selected ribonuclease (RNase) producing strains. Of the 150 pseudomonads screened, 6 were found to produce an extracellular RNase activity when grown on solid medium. In broth culture, the RNase activity from these six species remained bound to the cells unless gelatin was added to the medium. Gelatin was essential for the release of RNase in the broth culture, but the pH of the medium, addition of potential inducers such as nucleic acids, or addition of cations did not affect this release. However, gelatin did not appear to induce the synthesis of the enzyme. Strain B-88, identified as Pseudomonas maltophilia, was selected for further study of the enzyme. The extracellular RNase isolated from B-88 broth cultures could be separated in two fractions on the basis of the molecular weight by the ultrafiltration technique. The low molecular weight fraction reacts optimally at temperatures between 55 and 60 degrees C and optimal pH values varying from 7.4 to 9.5. At neutral or alkaline pH, the enzyme was stable at temperatures below 37 degrees C but was inactivated at 55 degrees C. The RNase was inhibited by mercury and cobalt and stimulated by magnesium.
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PMID:Production of an extracellular ribonuclease by Pseudomonas maltophilia. 3 76

Pseudomonas aeruginosa (ATCC 9027) releases four periplasm-located enzymes, i.e., ribonuclease (EC 3.1.4.22; EC 3.1.4.23), alkaline phosphatase (EC 3.1.3.1), cyclic-2', 3'-phosphodiesterase (EC 3.1.4.d), and 5'-nucleotidase (EC 3.1.3.5) into the medium during growth. Ribonuclease and alkaline phosphatase are classed as enzymes which are readily extracted by osmotic shock and spheroplast formation whereas cyclic-2',3'-phosphodiesterase and 5'-nucleotidase are classed as enzymes which are not readily extracted by these procedures. In view of the relative ease of extraction of the former enzymes it is suggested that the lattter enzymes, cyclic-2',3'-phosphodiesterase and 5'-nucleotidase, are bound and located in the periplasm in a manner different to ribonuclease and alkaline phosphatase.
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PMID:The release and characterization of some periplasm-located enzymes of Pseudomona aeruginosa. 18 95

Ribosomal protein S4 of Escherichia coli was bound to 16-S ribosomal RNAs from several bacterial species and the complexes digested with pancreatic ribonuclease in an effort to isolate heterologous RNA binding sites for protein S4. 16-S RNAs from Aeromonas punctata, Pseudomonas fluorescens and Vibrio cuneatus each gave rise to protected fragments whose electrophoretic mobility was 7S, i.e. similar to that of the fragment generated from E. coli 16-S RNA using the same conditions. No comparable fragment was obtained from 16-S RNA of either Bacillus subtilis or Bacillus stearothermophilus, if E. coli protein S4 was present prior to digestion. The protected 7-S RNA fragment from A. punctata and the subfragments obtained from it by gel electrophoresis under denaturing conditions were characterized further by fingerprinting and nucleotide sequence analysis. The sequence of many of the T1 ribonuclease oligonucleotides was obtained and compared to those from the E. coli 7-S fragment. This has permitted a tentative identification of the sequences of A. punctata 16-S RNA which are protected by E. coli protein S4, namely, the regions homologous to the E. coli sequence from section M through C''. The fingerprints of the protected 7-S fragments from both P. fluorescens and V. cuneatus were sufficiently different from that of the E. coli 7-S fragment that no conclusions regarding sequence homologies could be drawn.
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PMID:The binding site of Escherichia coli ribosomal protein S4 on 16-S ribosomal RNA from different bacterial species. 82 36

Strains from type culture collections and clinical isolates belonging to the Aeromonas and Pseudomonas genera were identified with conventional tests. Production of extra-cellular enzymes and haemolysins were detected by simple plate agar methods. The following enzymes were found to be of special value for a rapid and simple classification of certain species in both genera: potease (casein and gelatin agar), lecithinase (lecithin agar), and deoxyribonuclease (DNA agar). Elastase, staphylolytic enzyme, lipase, ribonuclease, amylase, and egg yolk reaction were other enzymes studied. However, these tests were not positive for more than 90% of any species. A. hydrophila, A. salmonicida, and P. aeruginosa were haemolytic on agar containing rabbit erythrocytes.
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PMID:Characterization of three Aeromonas and nine pseudomonas species by extracellular enzymes and haemolysins. 117 Apr 82

Pseudomonas exotoxin A (PE) is a protein toxin composed of three structural domains. Functional analysis of PE has revealed that domain I is the cell-binding domain and that domain III functions in ADP ribosylation. Domain II was originally designated as the translocation domain, mediating the transfer of domain III to the cytosol, because mutations in this domain result in toxin molecules with normal cell-binding and ADP-ribosylation activities but which are not cytotoxic. However, the results do not rule out the possibility that regions of PE outside of domain II also participate in the translocation process. To investigate this problem, we have now constructed a toxin in which domain III of PE is replaced with barnase, the extracellular ribonuclease of Bacillus amyloliquefaciens. This chimeric toxin, termed PE1-412-Bar, is cytotoxic to a murine fibroblast cell line and to a murine hybridoma resistant to the ADP-ribosylation activity of PE. A mutant form of PE1-412-Bar with an inactivating mutation in domain II at position 276 was significantly less toxic. Because the cytotoxic effect of PE1-412-Bar was due to the ribonuclease-activity of barnase molecules which had been translocated to the cytosol, we conclude that domain II of PE is not only essential but also probably sufficient to carry out the translocation process.
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PMID:Translocation mediated by domain II of Pseudomonas exotoxin A: transport of barnase into the cytosol. 156 15

We have constructed a chimeric toxin composed of Pseudomonas exotoxin A (PE) and the extracellular ribonuclease of Bacillus amyloliquefaciens, barnase. The chimeric protein, termed PE-Bar, reacted with both anti-PE and anti-barnase antisera and had both ADP ribosylation and ribonuclease activities. The chimeric toxin was cytotoxic to the murine fibroblast cell line L929 and to a murine hybridoma resistant to PE. A mutant form of PE-Bar lacking ADP-ribosylating activity was still cytotoxic to L929 cells. Because treatment of cells prelabeld with [3H]uridine resulted in a decrease in their RNA content, we conclude that this cytotoxic effect was due to the ribonuclease activity of barnase molecules that had been translocated to the cytosol. It is now possible to construct chimeric toxins with two or more enzymatic activities that can be delivered to the cytosol of the target cells.
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PMID:Barnase toxin: a new chimeric toxin composed of pseudomonas exotoxin A and barnase. 190 Apr 55

Bacteriophage phi 6 contains three segments of double-stranded RNA within a nucleocapsid. Plasmids containing cDNA copies of the large genomic segment direct the synthesis of viral proteins that assemble into procapsids in Escherichia coli or Pseudomonas phaseolicola. These structures are dodecahedral assemblages of proteins P1, P2, P4, and P7. We report in this paper that these particles are capable of packaging viral single-stranded plus-sense RNA in vitro. The packaging reaction requires the presence of ATP or dATP. Synthesis of minus strands takes place within this filled procapsid in the presence of all four nucleoside triphosphates. Packaged ssRNA is found to be protected from added ribonuclease.
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PMID:In vitro packaging of the bacteriophage phi 6 ssRNA genomic precursors. 201 38

Secondary structure models for the ribonuclease (RNAase) P RNAs of Bacillus subtilis and E. coli were derived by a phylogenetic comparative analysis of published sequences as well as four novel ones. The RNAase P RNA genes from Bacillus megaterium, Bacillus brevis, Bacillus stearothermophilus, and Pseudomonas fluorescens were cloned, sequenced, and compared with the other available sequences. Regions of pairing were identified by the occurrence of homologous complementary sequences that vary among the compared molecules. A common core of primary and secondary structure can be identified in all these RNAase P RNAs. The previously noted striking differences between the Bacillus and the enteric RNAase P RNAs arise not only from point mutations, but from the addition or deletion of structural domains. The primary and secondary structural features that are common to all of the RNAase P RNAs are likely to be the elements involved in the binding and cleavage of tRNA precursors, and in the interaction with the RNAase P protein.
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PMID:The secondary structure of ribonuclease P RNA, the catalytic element of a ribonucleoprotein enzyme. 244 69

The present studies were conducted to identify factors in human purulent material that might limit or enhance the activity of ciprofloxacin against bacteria causing suppurative infection. Ciprofloxacin, imipenem, and ampicillin were tested with regard to binding or inactivation by pus. The bactericidal activity of ciprofloxacin and imipenem were tested against Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, or Staphylococcus aureus in human pus with a pH of 6.0 incubated at 37 degrees C under aerobic or anaerobic conditions. The effect of single or combination drug therapy with 20 mg/kg of ciprofloxacin, imipenem, or rifampin given every 12 hours was tested against E. coli or P. aeruginosa in polymicrobic murine abscesses that had been produced by subcutaneous injection of either of those organisms mixed with Bacteroides fragilis and autoclaved human stool. Antibiotic levels and the number of bacteria surviving in pus were quantitated. Therapy of subcutaneous abscesses was delayed 72 hours to test drug efficacy against organisms in well-established infections. Levels of ampicillin, imipenem, or ciprofloxacin were reduced from 10 micrograms/ml to 3.1 +/- 4.0, 2.7 +/- 3, or 5.8 +/- 2 micrograms/ml, respectively, after incubation in eight pus specimens for 24 hours at 37 degrees C. Ampicillin levels were reduced to less than 1 microgram/ml in four pus specimens containing beta-lactamase. Imipenem levels were undetectable in two specimens and were 0.2 micrograms/ml in one specimen. Ciprofloxacin binding to pus supernate or sediment appeared to be explained by its binding to the deoxyribonucleic acid (DNA) present in pus. Activity of 5 micrograms/ml of ciprofloxacin against four E. coli or K. pneumoniae strains in pus in vitro was greater than that of twofold higher concentrations of imipenem. The bactericidal activity of ciprofloxacin and imipenem were comparable but substantially reduced against S. aureus and P. aeruginosa in pus. Ciprofloxacin alone or regimens combining ciprofloxacin with rifampin or rifampin plus imipenem reduced the number of E. coli in polymicrobic subcutaneous abscesses but had little effect on P. aeruginosa in polymicrobic abscesses. The anaerobic abscess milieu appeared to inhibit the growth of P. aeruginosa. Ciprofloxacin activity in abscess fluid did not appear to be adversely affected by acid pH, aerobic or anaerobic conditions of incubation, the abscess constituents, or the binding of ciprofloxacin to the DNA in pus. Ciprofloxacin was bound to DNA of bacterial or human origin. Binding by pus was reversible, and binding to DNA extracts of pus was blocked by pretreatment of extracts with deoxyribonuclease but not by pretreatment with ribonuclease.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Effect of the abscess environment on the antimicrobial activity of ciprofloxacin. 258 67

The means by which coxsackievirus type A9 (CA9) is inactivated by proteolytic enzymes was investigated. After reaction of (14)C-leucine-labeled CA9 with Pronase, free leucine was liberated as measured by radiochromatography. Treatment of (14)C-leucine-labeled CA9 with trypsin or proteolytic filtrates of Pseudomonas aeruginosa caused the release of a variety of labeled substances. The extent of viral ribonucleic acid (RNA) release after exposure of CA9 to Pronase was determined by RNA infectivity tests or trichloroacetic acid solubility tests. Infective viral RNA was found not to be consistently released by reaction of CA9 with Pronase, but further treatment with 1% sodium dodecyl sulfate at pH 7.0 promoted viral RNA release. Sodium dodecyl sulfate treatment of CA9 that had not been reacted with Pronase did not inactivate virus or cause viral RNA release. Reaction of Pronase with (32)P-labeled CA9 resulted in the liberation of virus components soluble in cold trichloroacetic acid, whereas untreated CA9 or CA9 reacted with ribonuclease were precipitated by cold trichloroacetic acid. These results demonstrate that the primary means by which protease-sensitive enteroviruses are inactivated is by degradation of the virus capsid, with subsequent release of viral RNA.
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PMID:Degradation of coxsackievirus type A9 by proteolytic enzymes. 420 58


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