E. cloacae

The occurrence of 4-hydroxybenzoate decarboxylase was also found in facultative anaerobic bacteria, E. cloacae P240, and the enzyme was purified and characterized. The activity of the cell-free extract of E. cloacae P240 was determined to be 13.7 ijumol min (mg protein) at 30°C, which was much higher than... 

The occurrence of 3,4-dihydroxybenzoate decarboxylase was also found widely in facultative anaerobes. Among them, Enterobacter cloacae P241 showed the highest activity of 3,4-hydroxybenzoate decarboxylase, and the activity of the cell-free extract of E. cloacae P241 was determined to be 0.629 p.mol min (mg protein) at 30°C, which was more than that of C. hydroxybenzoicum, 0.11 (xmol min mg protein)" at 25°C. The E. cloacae P241 enzyme has a molecular mass of 334 kDa and consists of six identical 50 kDa subunits. The value for 3,4-dihydroxybenzoate was 177 p.M. The enzyme is also characteristic of its narrow substrate specificity and does not act on 4-hydroxybenzoate and other benzoate derivatives. The properties of E. cloacae P241 3,4-hydroxybenzoate decarboxylase were similar to those of C. hydroxybenzoicum in optimum temperature and pH, oxygen sensitivity, and substrate specificity. 

The reaction product of the reserve carboxylation reaction was isolated and identified to be 3,4-dihydroxybenzoic acid by NMR and NMR with the authentic 3,4-dihydroxybenzoic acid as a reference. The carboxylation reaction of catechol to 3,4-dihydroxybenzoate was affected by the concentration of KHCO3. The carboxylation activity of E. cloacae P241 3,4-dihydroxybenzoate decarboxylase in the presence of 0.1 M KHCO3 was only 15% of that in the presence of 3 M KHC03. In the case of C. hydroxybenzoicum 3,4-dihydroxybenzote decarboxylase, only 0.01 mM 3,4-dihydroxybenzoate was formed from 6mM catechol in the presence of 50 mM NaHC03 by 40 min incubation. The difference in molar conversion ratios might be caused by the concentration of bicarbonate added to the reaction mixture. 

The purified E. cloacae P240 4-hydroxybenzoate decarboxylase did not catalyze the carboxylation of phenylphosphate, indicating phenolphosphate... 

In the aligned primary structures of class I decarboxylases, the conserved amino acid residues are scattered over their primary structures. There have been few reports to identify the amino acid residues essential for catalytic activity or substrate binding. Huang et al. reported the E-X-P motif in the alignment analysis for 4-hydroxybenzoate decarboxylase of C. hydroxybenzoicum and its homologous unidentified proteins. The E-X-P motif is also conserved in pyrrole-2-carboxylate decarboxylase and indole-3-carboxylate decarboxylase (unpublished data). However, the corresponding motif sequence is not observed in the primary structures of 3,4-dihydroxybenzoate decarboxylase of E. cloacae P241. ... 

The selenate reductase from Enterobacter cloacae SLDla-1 functions only under aerobic conditions, and is not able to serve as an electron acceptor for anaerobic growth, in contrast to the periplasmic enzyme from Thauera selenatis (Schroder et al. 1997). In E. cloacae there are separate nitrate and selenate reductases, both of which are membrane-bound. The selenate reductase is able to reduce chlorate and bromate though not nitrate, contains Mo, heme and nonheme iron, and consists of three subunits in an a3p3y3 configuration. 

Based on chemical evidence and mass spectroscopy studies, the mechanism of inhibition shown in Scheme 2 has been proposed. The interactions of 6a with /6-lactamases of classes A, B, C, and D were investigated ki-netically [35]. A crystal structure of 6a in complex with E. cloacae 908R /6-lactamase has been reported recently [36]. 

Intra-abdominal infections Intra-abdominal infections, including peritonitis caused by E. coli, Klebsiella sp. including K. pneumoniae, Enterobacter sp. including E. cloacae, P. aeruginosa, Citrobacter sp. including C. freundii and Serratia sp. including S. marcescens. 

Benzyl isothiocyanate was identified in aqueous extracts of C. sativa foliage by Lovett and Duffield ( ). Tang, Bhothipaksa and Frank ( ) showed that E. cloacae was capable of degrading benzyl isothiocyanate to hydrogen sulfide and benzylamine. Tests were, accordingly, carried out with incubated leaf washings of Camelina and showed the presence of hydrogen sulfide and... 

The enteric bacterium Enterobacter cloacae produces a nitroreductase that reduces nitrofurans, nitroimidazoles, nitrobenzene derivatives, and quinones (Bryant DeLuca, 1991). This oxygen-insensitive enzyme has been purified and is known to require FMN to transfer reducing equivalents from NAD(P)H to the nitroaromatic compounds, TNT being the preferred substrate. Aerobically, this enzyme reduces nitrofurazone through the hydroxylamine intermediate, which then tautomerizes to yield an oxime end-product. Anaerobically, however, the reduction proceeds to the fully reduced amine adduct. When E. cloacae was grown in the presence of TNT, the nitroreductase activity increased five- to tenfold. 

Cells were transferred from an overnight liquid culture to fresh medium and grown overnight ( 18 h) on a gyrorotary shaker at room temperature. The cells were harvested by centrifugation (11,000 g, 10 min) and resuspended in sterile assay buffer (0.01 M phosphate buffer, Na salt, 0.26 M NaCl, pH 6.78 the pH prior to sterilization was 7.20). The cell concentration was adjusted to approximately 5 x 108/mL as judged by optical density of the solution. The actual numbers in dilutions of the cell suspensions were determined by direct counts. E. cloacae was grown as described, except that the M9 contained 0.5 g/L of NaCl. 

Pure Culture Studies. Two bacteria were cultured to study the decomposition of H202, Vibrio alginolyticus and Enterobacter cloacae. V. alginolyticus was selected because it is an extremely common inhabitant of environments like the Chesapeake Bay. Vibrios may provide up to 50% of the culturable bacterial species in the bay (60). E. cloacae was studied because it is commonly found in freshwater environments (94). 

Amino acids E. cloacae-214 (Ref. 46) E. coli B. cereus B. licheniformis S. aureus ... 

Continuing use of the third-generation cephalosporins and the introduction of p-lactamase inhibitor combinations (clavulanate with amoxycillin or ticarcillin, sulbactam with ampicillin, and tazobactam with piperacillin see section 4.2) resulted in the appearance of plasmids encoding class C P-lactamases. After several unconfirmed reports, the first proof that a class C P-lactamase had been captured on a plasmid came in 1990 when transmissible resistance to a-methoxy and oxyimino-P-lactams was shown to be mediated by an enzyme whose gene was 90% identical to the ampC gene of E. cloacae. They have subsequently been found worldwide. Strains with plasmid-mediated AmpC enzymes are typically resistant to aminopenicillins (ampicillin or amoxycillin), carboxypenicillins (carbenicillin or ticarcillin) and ureidopenicillins (piperacillin). The enzymes also provide resistance to the oxyimino cephalosporins (ceftazidime, cefo-... 

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