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unraveling the dha cluster in citrobacter werkmanii: comparative genomic analysis of bacterial 1,3-propanediol biosynthesis clusters.in natural 1,3-propanediol (pdo) producing microorganisms such as klebsiella pneumoniae, citrobacter freundii and clostridium sp., the genes coding for pdo producing enzymes are grouped in a dha cluster. this article describes the dha cluster of a novel candidate for pdo production, citrobacter werkmanii dsm17579 and compares the cluster to the currently known pdo clusters of enterobacteriaceae and clostridiaceae. moreover, we attribute a putative function to two previously unannotated orfs, orf ...201423996279
occurrence and characteristics of extended spectrum beta-lactamases-producing enterobacteriaceae from foods of animal origin.presence of extended spectrum beta-lactamases (esbl) in bacteria is a growing health concern of global significance. the local, regional, national, and international epidemiological studies for extended spectrum beta-lactamases-producing enterobacteriaceae and their encoding genes in foods are still incomplete. the objective of this study was to determine the occurrence of extended spectrum beta-lactamases-producing enterobacteriaceae and the characteristics of their encoding genes from a total ...201626991276
novel variants of the qnrb gene, qnrb22 and qnrb23, in citrobacter werkmanii and citrobacter freundii. 201020421404
structure of the glycerol phosphate-containing o-specific polysaccharide and serological studies on the lipopolysaccharides of citrobacter werkmanii pcm 1548 and pcm 1549 (serogroup o14).the o-specific polysaccharide was obtained by mild acid hydrolysis of the lipopolysaccharide of citrobacter werkmanii pcm 1548 and pcm 1549 (serogroup o14) and found to contain d-glucose, d-glucosamine and glycerol-1-phosphate in molar ratios 2 : 2 : 1. based on methylation analysis and 1h and 13c nuclear magnetic resonance spectroscopy data, it was established that the o-specific polysaccharides from both strains have the identical branched tetrasaccharide repeating unit with 3,6-disubstituted ...200818811720
structure of the o-specific polysaccharide from the lipopolysaccharide of citrobacter gillenii o11, strain pcm 1540.the o-specific polysaccharide of the lipopolysaccharide of citrobacter gillenii pcm 1540 (serogroup o11) consists of d-glc, d-man, d-galnac, d-glcnac, 2-acetamido-2,6-dideoxy-d-galactose (d-fucnac) and o-acetyl groups in the ratios 2:1:1:1:1:1. on the basis of sugar and methylation analyses and smith-degradation along with 1d and 2d 1h and 13c nmr spectroscopy, the following structure of the branched hexasaccharide repeating unit was established: [structure: see text]. citrobacter werkmanii pcm ...200312801712
cloning and sequencing of the beta-lactamase gene and surrounding dna sequences of citrobacter braakii, citrobacter murliniae, citrobacter werkmanii, escherichia fergusonii and enterobacter cancerogenus.to further identify the origins of plasmid-mediated cephalosporinases that are currently spreading worldwide, the chromosomal beta-lactamase genes of citrobacter braakii, citrobacter murliniae, citrobacter werkmanii reference strains and of escherichia fergusonii and enterobacter cancerogenus clinical isolates were cloned and expressed into escherichia coli and sequenced. these beta-lactamases had all a single pi value >8 and conferred a typical ampc-type resistance pattern in e. coli recombinan ...200212393205
re-speciation of the original reference strains of serovars in the citrobacter freundii (bethesda-ballerup group) antigenic scheme of west and edwards.the antigenic scheme for the bethesda-ballerup group of bacteria established by west and edwards in 1954 has continued to be applied as a serotyping scheme for citrobacter freundii. in 1993, however, the classification of the citrobacter was drastically revised and the species c. freundii redefined by brenner et al. accordingly, to judge the propriety to continuously use a single antigenic scheme for the c. freundii complex, the 90 reference strains listed in the antigenic scheme for c. freundii ...19969013489
classification of citrobacteria by dna hybridization: designation of citrobacter farmeri sp. nov., citrobacter youngae sp. nov., citrobacter braakii sp. nov., citrobacter werkmanii sp. nov., citrobacter sedlakii sp. nov., and three unnamed citrobacter genomospecies.dna relatedness studies (hydroxyapatite method) were done on 112 strains of citrobacteria. by using the recommended definition of a genomospecies 11 genomospecies were identified in the genus citrobacter. these genomospecies were separable by their biochemical profiles. citrobacter koseri (citrobacter diversus) and citrobacter amalonaticus proved to be homogeneous species, as previously described. c. amalonaticus biogroup 1, as described by farmer et al. (j. clin. microbiol. 21:46-76, 1985), was ...19938240948
structure of an abequose-containing o-polysaccharide from citrobacter freundii o22 strain pcm 1555.the lipopolysaccharide of citrobacter freundii o22 (strain pcm 1555) was degraded under mild acidic conditions and the o-polysaccharide released was isolated by gel chromatography. sugar and methylation analyses along with (1)h and (13)c nmr spectroscopy, including two-dimensional (1)h,(1)h roesy and (1)h,(13)c hmbc experiments, showed that the repeating unit of the o-polysaccharide has the following structure: alpha-abep 1 -->3 --> 2)-alpha-d-manp-(1-->4)-alpha-l-rhap-(1-->3)-alpha-d-galp-(1--> ...200919576576
two chromosomally located qnrb variants, qnrb6 and the new qnrb16, in citrobacter spp. isolates causing bacteraemia.the objective of this study was to determine the prevalence of the plasmid-borne quinolone resistance genes qnra, qnrb and qnrs in a collection of enterobacteriaceae causing bacteraemia. the presence of the three genes was tested for using multiplex pcr in 306 clinical isolates. plasmid analysis was performed using i-ceui and s1 nuclease digestion and hybridization with specific probes for the qnr and 23s rrna genes. five strains were found to carry a qnr gene, one of which, qnrb16, a new varian ...200919392890
novel variant of the qnrb gene, qnrb12, in citrobacter werkmanii. 200818086833
the identity of the o-specific polysaccharide structure of citrobacter strains from serogroups o2, o20 and o25 and immunochemical characterisation of c. youngae pcm 1507 (o2a,1b) and related strains.serological studies using sds-page and immunoblotting revealed that from five strains that are ascribed to citrobacter serogroup o2, four strains, pcm 1494, pcm 1495, pcm 1496 and pcm 1507, are reactive with specific anti-citrobacter o2 serum. in contrast, strain pcm 1573 did not react with anti-citrobacter o2 serum and, hence, does not belong to serogroup o2. the lps of citrobacter youngae o2a,1b (strain pcm 1507) was degraded under mild acidic conditions and the o-specific polysaccharide (ops) ...200312727368
proteome responses of citrobacter werkmanii bf-6 planktonic cells and biofilms to calcium chloride.calcium ions are well-known as intracellular second messengers that also have an important extracellular structural role for bacteria. recently, we found that denser biofilms were formed by citrobacter werkmanii bf-6 in the presence of 400 mm ca(2+) than that of 12.5mm ca(2+). therefore, we employed two-dimensional (2-d) electrophoresis methods to investigate the proteome profiles of planktonic cells and biofilms in bf-6 under different concentrations of ca(2+). meanwhile, bf-6 biofilm architect ...201626732726
effects of nutritional and environmental conditions on planktonic growth and biofilm formation of citrobacter werkmanii bf-6.citrobacter sp. is a cause of significant opportunistic nosocomial infection and is frequently found in human and animal feces, soil, and sewage water, and even in industrial waste or putrefaction. biofilm formation is an important virulence trait of citrobacter sp. pathogens but the process and characteristics of this formation are unclear. therefore, we employed in vitro assays to study the nutritional and environmental parameters that might influence biofilm formation of c. werkmanii bf-6 usi ...201324018970
high yield 1,3-propanediol production by rational engineering of the 3-hydroxypropionaldehyde bottleneck in citrobacter werkmanii.imbalance in cofactors causing the accumulation of intermediates in biosynthesis pathways is a frequently occurring problem in metabolic engineering when optimizing a production pathway in a microorganism. in our previous study, a single knock-out citrobacter werkmanii ∆dhad was constructed for improved 1,3-propanediol (pdo) production. instead of an enhanced pdo concentration on this strain, the gene knock-out led to the accumulation of the toxic intermediate 3-hydroxypropionaldehyde (3-hpa). t ...201626822953
1,3-propanediol production with citrobacter werkmanii dsm17579: effect of a dhad knock-out.1,3-propanediol (pdo) is a substantially industrial metabolite used in the polymer industry. although several natural pdo production hosts exist, e.g. klebsiella sp., citrobacter sp. and clostridium sp., the pdo yield on glycerol is insufficient for an economically viable bio-process. enhancing this yield via strain improvement can be achieved by disconnecting the production and growth pathways. in the case of pdo formation, this approach results in a microorganism metabolizing glycerol strictly ...201424885849
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