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Query: UMLS:C0519030 (Klebsiella)
 21,988 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In Pseudomonas aeruginosa, the synthesis of histidase, urocanase and amidase is severly repressed when succinate is added to a culture growing in pyruvate + ammonium salts medium. When growth is nitrogen-limited, catabolite repression by succinate of histidase and urocanase synthesis does not occur but succinate repression of amidase synthesis persists. Amidase synthesis is not regulated in the same way as histidase synthesis by the availability of other nitrogen compounds for growth. Growth of P. aeruginosa strain PACI in succinate + histidine media is nitrogen-limited since this strain is defective in a histidine transport system. When methyl-ammonium chloride is added to succinate + histidine media, growth inhibition occurs. Mutants isolated from succinate + histidine + methylammonium chloride plates were found to be resistant to catabolite repression by succinate even in ammonium salts media. It is suggested that the hut genes of P. aeruginosa may be regulated in the same way as in Klebsiella aerogenes, by induction by urocanate and activation by either the cyclic AMP-dependent activator protein or by glutamine synthetase.
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PMID:The effect of nitrogen limitation on catabolite repression of amidase, histidase and urocanase in Pseudomonas aeruginosa. 0 23

We used polyacrylamide gel electrophoresis to examine the regulation and adenylylation states of glutamine synthetases (GSs) from Escherichia coli (GS(E)) and Klebsiella aerogenes (GS(K)). In gels containing sodium dodecyl sulfate (SDS), we found that GS(K) had a mobility which differed significantly from that of GS(E). In addition, for both GS(K) and GS(E), adenylylated subunits (GS(K)-adenosine 5'-monophosphate [AMP] and GS(E)-AMP) had lesser mobilities in SDS gels than did the corresponding non-adenylylated subunits. The order of mobilities was GS(K)-AMP < GS(K) < GS(E)-AMP < GS(E). We were able to detect these mobility differences with purified and partially purified preparations of GS, crude cell extracts, and whole cell lysates. SDS gel electrophoresis thus provided a means of estimating the adenylylation state and the quantity of GS present independent of enzymatic activity measurements and of determining the strain origin. Using SDS gels, we showed that: (i) the constitutively produced GS in strains carrying the glnA4 allele was mostly adenylylated, (ii) the GS-like polypeptide produced by strains carrying the glnA51 allele was indistinguishable from wild-type GS(K), and (iii) strains carrying the glnA10 allele contained no polypeptide having the mobility of GS(K) or GS(K)-AMP. Using native polyacrylamide gels, we detected the increased amount of dodecameric GS present in cells grown under nitrogen limitation compared with cells grown under conditions of nitrogen excess. In native gels there was neither a significant difference in the mobilities of adenylylated and non-adenylylated GSs nor a GS-like protein in cells carrying the glnA10 allele.
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PMID:Glutamine synthetase regulation, adenylylation state, and strain specificity analyzed by polyacrylamide gel electrophoresis. 3 58

The prosthetic group of citrate (pro-3S)-lyase [citrate oxaloacetate-lyase (pro-3S-CH2COO- leads to acetate); EC 4.1.3.6] from Klebsiella aerogenes was obtained by mild alkaline hydrolysis of the enzyme and purified by DEAE-cellulose chromatography. Several chemical and enzymatic degradation products of the compound have been isolated, and analyses of these have shown the structure of the prosthetic group to be 3'(or 2') leads to 1 inch-(5 inches-phosphoribosyl) dephosphocoenzyme A. Proof as to the exact linkage between the two ribose moieties and the anomeric configuration of the glycosidic bonds has not yet been obtained. A similar analysis was obtained for a product isolated after Pronase digestion of the enzyme (without alkaline hydrolysis). The isolated prosthetic group also can serve as a substrate for a crude preparation of acetate:-SH-(acyl carrier protein) enzyme ligase (AMP) from K. aerogenes, pure pig heart citrate (si)-synthase (EC 4.1.3.7), and pure rat liver ATP citrate (pro-3S)-lyase (EC4.1.3.8). This compound is the first shown to substitute for coenzyme A in the latter reaction.
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PMID:Structure of the prosthetic group of Klebsiella aerogenes citrate (pro-3S)-lyase. 18 May 26

Derivatives of Salmonella typhimurium carrying F prime or P prime plasmids with Klebsiella nif and his genes had specific nitrogenase activities similar to Klebsiella in selective conditions, even to showing "hyperinduction" under argon. No evidence was obtained for catabolite repression of normal nif expression but dibutyl cyclic AMP often augmented "hyperinduction". In non-selective conditions the Klebsiella his nif determinants were rapidly lost from the plasmids; the low levels of nif expression and temperature-sensitive his expression previously reported were probably due to ready loss of his nif in the test conditions used.
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PMID:Expression of Klebsiella nif and his genes in Salmonella typhimurium. 19 33

Immunochemical studies demonstrated that Klebsiella pneumoniae (Aerobacter aerogenes) ATCC 8724 produces only a single diol dehydratase whether grown on glycerol or on 1,2-propanediol. The enzyme was subject to induction by 1,2-diols and to catabolite repression reversed by cyclic AMP.
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PMID:Coenzyme B12-dependent diol dehydratase: regulation of apoenzyme synthesis in Klebsiella pneumoniae (Aerobacter aerogenes) ATCC 8724. 21 Jan 57

1. The enzyme citramalate from Clostridium tetanomorphum is not stable in crude extracts. However, the inactive enzyme can be reactivated by incubation with dithioerythritol followed by acetylation with acetic anhydride. Reactivation was also obtained with acetate, ATP, MgCl2 and acetate : SH-enzyme ligases (AMP) from C. tetanomorphum or Klebsiella aerogenes. 2. Incubation of the inactive enzyme with iodoacetate resulted in rapid loss of enzymic activity as determined by reactivation with acetic anhydride whereas the active enzyme was stable in the presence of iodoacetate. Using ido[2-(14)C]acetate the sites of carboxymethylation and acetylation where identified as cysteamine residues of the enzyme. The results demonstrate that the active enzyme contains acetyl thiolester residues which play the central role in the catalytic mechanism. 3. Citramalate lyase was purified by a procedure almost identical to that already described for citrate lyase from K. aerogenes. The molecular weight of citramalate lyase is equal to that of citrate lyase (Mr = 5.2--5.8 X 10(5)) as estimated by gel chromatography and sucrose gradient centrifugation. Polyacrylamide gel elctrophoresis of citramalate lyase in sodium dodecylsulfate yielded three polypeptide chains (Mr: alpha 5.3--5.6 X 10(4); beta 3.3--3.6 X 10(4); gamma 1.0--1.2 X 10(4)) in probably equal molar amounts. These data lead to a hexameric structure (alpha,beta,gamma)6 of the complete enzyme. 4. Pantothenate (5 mol/mol of enzyme) and the essential cysteamine residues were exclusively present in the gamma-chain, the acyl carrier protein of citramalate lyase. The acyl exchange and cleavage functions, probably catalysed by the alpha and beta-subunits, were measured with acyl-CoA derivatives which were able to substitute for the natural acyl carrier. 5. The results demonstrate that citramalate lyase is an enzyme complex with structure and functions closely resembling those of citrate lyase. Although the similarity between citramalate lyase and citrate lyases from various organisms suggests a close evolutionary relationship, these occur in very different, unrelated bacteria. A parallel situation found in the distribution of the nitrogenase system among procaryotes is discussed.
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PMID:The enzyme complex citramalate lyase from Clostridium tetanomorphum. 127 56

The Klebsiella aerogenes gene maoA, which is involved in the synthesis of monoamine oxidase, was induced by tyramine and the related compounds, subjected to catabolite and ammonium ion repression, and cloned. The nucleotide sequence of the region involved in monoamine oxidase synthesis was determined. Two open reading frames, the maoA gene and a hitherto unknown gene (maoC), were found. These are located between a potential promoter sequence and a transcriptional terminator sequence. A region of the Escherichia coli chromosome that was highly homologous to the Klebsiella maoA gene was found. The potential maoA gene is located at 30.9 min on the E. coli chromosome. Analysis of the amino acid sequences of the first 11 amino acids from the N terminus of the purified monoamine oxidase agrees with those deduced from the nucleotide sequence of the maoA gene. The leader peptide extends over 30 amino acids and has the characteristics of a signal sequence. Primer extension and S1 nuclease mapping of transcripts generated in vivo suggests that the tyramine-induced mRNA starts at a site 62 bases upstream from the ATG initiation codon of the maoC gene. In the putative promoter region, a high degree of similarity to the consensus sequence for the binding site of cyclic AMP receptor protein was found. Thus, the mao region is composed of two cistrons, and the mao operon is regulated by monoamine compounds, glucose, and ammonium ions.
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PMID:A monoamine-regulated Klebsiella aerogenes operon containing the monoamine oxidase structural gene (maoA) and the maoC gene. 155 68

The promoter region preceding the hutUH operon in Klebsiella aerogenes contains two oppositely oriented, overlapping promoters. In the absence of catabolite gene activator protein-cyclic AMP (CAP-cAMP), transcription proceeds primarily from the backward-oriented promoter (Pc), whose function has not yet been determined, and only very weakly from the forward hutUH promoter, hutUp. In the presence of CAP-cAMP, Pc is repressed and transcription from hutUp is favored. Two protein components required for this in vitro transcription system, RNA polymerase (RNAP) and CAP, were purified from K. aerogenes and were shown to be functionally interchangeable with the corresponding proteins from Escherichia coli, suggesting that E. coli RNAP could be used to study some aspects of hut transcription. We showed that a gradual activation of hutUp (by increasing concentrations of CAP, cAMP, or glycerol) resulted in a parallel repression of Pc, arguing in favor of a direct competition between the two promoters. The presence of a DNA sequence resembling the consensus for CAP-binding sites and centered at nucleotide -82 (relative to hutUp) initially suggested that a primary role of CAP was to repress Pc, thereby indirectly activating hutUp. However, the relatively slow formation of open complexes at Pc, even in the absence of CAP-cAMP, showed that Pc is a weak promoter and likely to be a poor competitor for RNAP. The observed dominance of Pc over hutUp suggested that the latter is an even weaker promoter. Thus, repression of Pc would not be sufficient to cause the observed increase in hutUp activity, and the CAP-cAMP complex must play a direct role in the activation of hutUp.
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PMID:In vitro transcription of the histidine utilization (hutUH) operon from Klebsiella aerogenes. 184 33

The in vitro effects of the single agents, and the synergistic/antagonistic action of three different combinations of ampicillin (AMP, CAS 69-53-4), cefotaxime (CTX, CAS 63527-52-6), mezlocillin (MEZ, CAS 51481-65-3), and piperacillin (PIP, CAS 61477-96-1) with the beta-lactamase inhibitor sulbactam (SUL, CAS 68373-14-8) were determined against 675 gram-positive and gram-negative, both aerobic and anaerobic bacteria. All the combinations of sulbactam and the antibiotics (1: 1, 1:2 and 1:4) exhibited very similar synergistic action. The percentage of the total strains tested for which synergistic activity was found was 51% with SUL + AMP (1:1), 24% with SUL + CTX (1:1), 31% with SUL + MEZ (1:1), and 28% with SUL + PIP (1:1). A fourfold or greater reduction of MIC's in the comparison with the antibiotics alone was found with 23% of the total strains tested for the SUL + AMP, with 9% of the strains tested with SUL + CTX, with 11% of the strains tested with SUL + MEZ, and with 15% of the strains tested with the SUL + PIP-combination. In the presence of sulbactam, 18% of the strains tested showed a significant reduction in the number of resistant strains with ampicillin, 7% with cefotaxime, 16% with mezlocillin, 14% with piperacillin, and in parallel there was an increase in the number of fully susceptible strains (shift from resistant or moderately sensitive to sensitive) by about 14%. In comparison with the antibiotic alone, the most marked reductions in the number of resistant strains on combination with sulbactam were as follows (the percentage of reduction is shown in brackets): for SUL + AMP and Acine-tobacter spp. (39% fewer resistant strains). Citrobacter spp. (-60%), Enterobacter aerogenes (-48%), Klebsiella oxytoca (-49%), Klebsiella pneumoniae (-63%), Morganella morganii (-74%), and Proteus vulgaris (-55%); for SUL + CTX and Acinetobacter spp. (-38%), Enterobacter cloacae (-6%), Klebsiella pneumoniae (-16%), Serratia marcescens (-9%), and Bacteroides fragilis (-31%); for SUL + MEZ and Acinetobacter spp. (-68%), Citrobacter spp. (-27%), Enterobacter spp. (-23%), Klebsiella pneumoniae (-32%), and Serratia marcescens (-19%); for SUL + PIP and Acinetobacter spp. (-41%), Citrobacter spp. (-30%), Klebsiella spp. (-30%), and Serratia marcescens (-33%).
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PMID:In vitro activity against clinically important gram-positive and gram-negative bacteria of sulbactam, alone and in combination with ampicillin, cefotaxime, mezlocillin, and piperacillin. 229 54

Pullulanase is an extracellular starch-debranching enzyme produced by Klebsiella pneumoniae. When its structural gene, pulA, is introduced into Escherichia coli, it is controlled by malT, the positive regulator gene of the maltose regulon. Characterization of the region 5' to pulA and of the beginning of the gene described herein demonstrate that (i) pullulanase is probably a lipoprotein; (ii) an additional malT-controlled promoter (the malX promoter) lies adjacent to the pulA promoter and is oriented in the opposite direction; (iii) in common with the three previously described malT-controlled promoters, the pulA and malX promoters have a conserved hexanucleotide (consensus sequence, 5'-GGATGGA) 35 base pairs upstream from the transcription initiation site; and (iv) upstream from this conserved hexanucleotide the pulA and malX promoters differ from the other mal promoters in that they lack any detectable binding site for the cyclic AMP-binding protein.
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PMID:Structure of two divergent promoters located in front of the gene encoding pullulanase in Klebsiella pneumoniae and positively regulated by the malT product. 390 92


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