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Localization of an origin of replication in Corynebacterium diphtheriae broad host range plasmid pNG2 that also functions in Escherichia coli.

Subcloning and protoplast transformation studies identified a 2.6 kb fragment of Corynebacterium diphtheriae plasmid pNG2 which contains an origin of replication (oriR). Molecular combination of the 2.6 kb oriR cartridge with Escherichia coli plasmid pUC18CmR enabled the E. coli cloning vector to replicate within several species of Corynebacterium host cells. A 2.6 kb plasmid formed from the oriR cartridge alone is capable of replicating in E. coli. This suggests that a single origin could be used in vectors shuttling between Corynebacterium spp. and E. coli.

Cloning, Molecular↗

Ammonium assimilation and nitrogen control in Corynebacterium glutamicum and its relatives: an example for new regulatory mechanisms in actinomycetes.

Nitrogen is an essential component of nearly all complex macromolecules in a bacterial cell, such as proteins, nucleic acids and cell wall components. Accordingly, most prokaryotes have developed elaborate control mechanisms to provide an optimal supply of nitrogen for cellular metabolism and to cope with situations of nitrogen limitation. In this review, recent advances in our knowledge of ammonium uptake, its assimilation, and related regulatory systems in Corynebacterium glutamicum, a Gram-positive soil bacterium used for the industrial production of amino acids, are summarized and discussed with respect to the situation in the bacterial model organisms, Escherichia coli and Bacillus subtilis, and in comparison to the situation in other actinomycetes, namely in mycobacteria and streptomycetes. The regulatory network of nitrogen control in C. glutamicum seems to be a patchwork of different elements. It includes proteins similar to the UTase/GlnK pathway of E. coli and expression regulation by a repressor protein as in B. subtilis, but it lacks an NtrB/NtrC two-component signal transduction system. Furthermore, the C. glutamicum regulation network has unique features, such as a new sensing mechanism. Based on its extremely well-investigated central metabolism, well-established molecular biology tools, a public genome sequence and a newly-established proteome project, C. glutamicum seems to be a suitable model organism for other corynebacteria, such as Corynebacterium diphtheriae and Corynebacterium efficiens.

Corynebacterium↗

Detection of mycoloylglycerol by thin-layer chromatography as a tool for the rapid inclusion of corynebacteria of clinical origin in the genus Corynebacterium.

A chemotaxonomic study of some corynebacteria isolated from clinical samples revealed characteristic thin-layer chromatographic patterns for meso-diaminopimelic acid containing species included in the genera Corynebacterium, Dermabacter and Brevibacterium. Notably, a specific compound was consistently detected in mycolic acid containing species of the genus Corynebacterium. This compound was composed by glycerol and mycolic acids and structural analyses carried out by fast atom bombardment mass spectrometry in C. minutissimum confirmed its identification as mycoloylglycerol. The chain length of mycoloyl groups in this molecule ranged from 28 to 34 carbon atoms, being mono-, di- or triunsaturated. Detection of mycoloylglycerol by thin-layer chromatography may be thus useful for the rapid inclusion of a great variety of corynebacteria of clinical origin in the genus Corynebacterium in laboratories employing chromatographic techniques as an adjunct for the identification of these microorganisms.

Brevibacterium↗

A numerical analysis of ribosomal RNA gene patterns for typing clinical isolates of Corynebacterium group D2.

Restriction digest fragments of DNA from 46 clinical isolates identified as Corynebacterium group D2, were separated by electrophoresis, Southern blotted onto nylon membranes and hybridized to a ribosomal RNA gene probe. The resulting band patterns were subjected to unweighed pair-group cluster analysis. Representative strains from the main clusters were compared with similarly prepared band patterns from type strains of human Corynebacterium species. The results indicate that strains identified as Corynebacterium group D2 represent a unique taxon and that computer-assisted analysis of rRNA gene restriction fragment polymorphism (ribotyping) could be a useful technique in epidemiological studies of these bacteria.

Bacterial Typing Techniques↗

Characterisation of a catabolic epoxide hydrolase from a Corynebacterium sp.

The epoxide hydrolase (EH) from Corynebacterium sp. C12, which grows on cyclohexene oxide as sole carbon source, has been purified to homogeneity in two steps, involving anion exchange followed by hydrophobic-interaction chromatography. The purified enzyme is multimeric (probably tetrameric) with a subunit size of 32,140 Da. The gene encoding Corynebacterium EH was located on a 3.5-kb BamHI fragment of C12 chromosomal DNA using a DNA probe generated by PCR using degenerate primers based on the N-terminal and an internal amino acid sequence. Sequencing and database comparison of the predicted amino acid sequence of Corynebacterium EH shows that it is similar to mammalian and plant soluble EH, and the recently published sequence of epichlorohydrin EH from Agrobacterium radiobacter AD1 [Rink, R., Fennema, M., Smids, M., Dehmel, U. & Janssen, D. B. (1997) J. Biol. Chem. 272, 14650- 14657), particularly around the catalytic site. All of these proteins belong to the alpha/beta-hydrolase-fold family of enzymes. Similarity to the mammalian microsomal EH is weaker.

Amino Acid Sequence↗

Application of MALDI-TOF MS to lysine-producing Corynebacterium glutamicum: a novel approach for metabolic flux analysis.

In the present work, a novel comprehensive approach of (13)C-tracer studies with labeling measurements by MALDI-TOF MS, and metabolite balancing was developed to elucidate key fluxes in the central metabolism of lysine producing Corynebacterium glutamicum during batch culture. MALDI-TOF MS methods established allow the direct quantification of labeling patterns of low molecular mass Corynebacterium products from 1 microL of diluted culture supernatant. A mathematical model of the central Corynebacterium metabolism was developed, that describes the carbon transfer through the network via matrix calculations in a generally applicable way and calculates steady state mass isotopomer distributions of the involved metabolites. The model was applied for both experimental planning of tracer experiments and parameter estimation. Metabolic fluxes were calculated from stoichiometric data and from selected mass intensity ratios of lysine, alanine, and trehalose measured by MALDI-TOF MS in tracer experiments either with 1-(13)C glucose or with mixtures of (13)C6/(12)C6 glucose. During the phase of maximum lysine production C. glutamicum ATCC 21253 exhibited high relative fluxes into the pentose phosphate pathway of 71%, a highly reversible glucose-6-phosphate isomerase, significant backfluxes from the tricarboxylic acid cycle to the pyruvate node consuming the lysine precursor oxaloacetate, 36% net flux of anaplerotic carboxylation and 63% contribution of the dehydrogenase branch in the lysine biosynthetic pathway. Due to the straightforward and simple measurements of selected labeling patterns by MALDI-TOF MS sensitively reflecting the flux parameters of interest, the presented approach has an excellent potential to extend metabolic flux analysis from single experiments with enormous experimental effort to a broadly applied technique.

Citric Acid Cycle↗

Corynebacterium JK: a cause of nosocomial device-related infection.

Ten cases of serious infection due to antibiotic-resistant Corynebacterium JK are reported. Five infections occurred in patients with hematologic malignancy and granulocytopenia, an association previously reported. Five additional nosocomial infections occurred in patients without underlying disease previously reported to be associated with JK. Nine of the 10 infections were nosocomial in origin and were associated with plastic devices that had been inserted into the patients. JK organisms were isolated from a variety of sources from an additional 40 uninfected patients. Although the majority of clinical isolates of Corynebacterium JK were contaminants, our experience suggests that as many as 20% of isolations are associated with serious nosocomial infections. Isolation of Corynebacterium JK--particularly in blood cultures--from patients with indwelling catheters or other devices is highly suggestive of the presence of a serious nosocomial infection.

Adult↗

The complete genome sequence and analysis of Corynebacterium diphtheriae NCTC13129.

Corynebacterium diphtheriae is a Gram-positive, non-spore forming, non-motile, pleomorphic rod belonging to the genus Corynebacterium and the actinomycete group of organisms. The organism produces a potent bacteriophage-encoded protein exotoxin, diphtheria toxin (DT), which causes the symptoms of diphtheria. This potentially fatal infectious disease is controlled in many developed countries by an effective immunisation programme. However, the disease has made a dramatic return in recent years, in particular within the Eastern European region. The largest, and still on-going, outbreak since the advent of mass immunisation started within Russia and the newly independent states of the former Soviet Union in the 1990s. We have sequenced the genome of a UK clinical isolate (biotype gravis strain NCTC13129), representative of the clone responsible for this outbreak. The genome consists of a single circular chromosome of 2 488 635 bp, with no plasmids. It provides evidence that recent acquisition of pathogenicity factors goes beyond the toxin itself, and includes iron-uptake systems, adhesins and fimbrial proteins. This is in contrast to Corynebacterium's nearest sequenced pathogenic relative, Mycobacterium tuberculosis, where there is little evidence of recent horizontal DNA acquisition. The genome itself shows an unusually extreme large-scale compositional bias, being noticeably higher in G+C near the origin than at the terminus.

Aged↗

rRNA gene RFLP as an identification tool for Corynebacterium species.

The value of rRNA gene RFLP analysis (ribotyping) as a tool for Corynebacterium and Turicella species identification was evaluated. Seventy-four strains representing 26 different species or subspecies were analysed by BstEII, SmaI and SphI ribotyping. Numerical analysis of the resulting rDNA banding patterns was performed by Dice coefficient correlation in order to establish a database for species identification. In general, most of the strains belonging to the same species clustered together. Interestingly, BstEII clustering of many species followed known phylogenetic lineages. This was not evident with the more heterogeneous SmaI and SphI patterns. The SmaI patterns contained a 1800 bp band in the digests of all species studied with the exception of Corynebacterium urealyticum. SphI digestion resulted in the most heterogeneous patterns. The information provided by all three enzymes was considered essential for the reliable linking of strains of unknown identity with defined species in the database. It is concluded that ribotyping provides an useful tool for screening and characterization of potentially new Corynebacterium species.

Bacterial Typing Techniques↗

A pyrolysis-mass spectrometry study of Corynebacterium spp.

Clinical (66) and collection (38) strains of Corynebacterium spp., including C. jeikeium and CDC group D2, and of Listeria monocytogenes were examined. Conventional characters used in species identification were assessed by a microbiochemical method, and pyrolysis-mass spectrometry (Py-MS) was performed with a Horizon Instruments PYMS 200X. Classification based on Py-MS data yielded clusters that corresponded with species identification and classification groups from conventional data. One small group of clinical strains, homogeneous in conventional tests and Py-MS, comprised isolates from sputum samples from patients undergoing ventilation; they were similar to collection strains of C. renale and C. striatum; the latter species has been implicated in chest infection. Another group, similar to C. minutissimum in both systems, comprised clinical strains isolated from urogenital specimens. L. monocytogenes strains were clearly distinct from Corynebacterium spp. Groups comprising CDC D2 strains and C. jeikeium were resolved, and were similar to other Corynebacterium spp. Two collection strains of C. xerosis were distinct in conventional tests and Py-MS.

Bacterial Typing Techniques↗

Corynebacterium atypicum sp. nov., from a human clinical source, does not contain corynomycolic acids.

An unusual gram-positive, facultatively anaerobic, catalase-positive, diphtheroid-shaped organism originating from an unknown human clinical source was characterized by biochemical, molecular chemical and molecular phylogenetic methods. Based on its morphological and biochemical characteristics and the presence of a murein based on meso-diaminopimelic acid, the unidentified organism was tentatively assigned to the genus Corynebacterium. However, the unknown organism was found to lack the distinctive, short-chain corynomycolic acids that are considered to be characteristic of this genus. Despite the absence of these characteristic lipids, comparative 16S rRNA gene sequencing showed that the unknown bacterium was phylogenetically a member of the genus Corynebacterium and was distinct from all currently known species. Based on both phenotypic and 16S rRNA sequence considerations, it is proposed that the unknown organism be classified as a novel species, Corynebacterium atypicum sp. nov. The type strain of C. atypicum is strain R2070T (=CCUG 45804T=CIP 107431T).

Corynebacterium↗

Corynebacterium halotolerans sp. nov., isolated from saline soil in the west of China.

A halotolerant, non-spore-forming actinobacterium was isolated from a soil sample from the west of China. The strain, designated YIM 70093(T) (=CCTCC AA 001024(T)=DSM 44683(T)), comprised Gram-positive, non-motile, diphtheroid and irregular rods. It grew in 0-25 % KCl (KCl could be substituted by NaCl or MgCl(2).6H(2)O), with optimum growth at 10 % KCl, and its optimal pH and cultivation temperature were 7.2 and 28 degrees C, respectively. On the basis of its morphological, physiological and phylogenetic characteristics, strain YIM 70093(T) should be classified in the genus CORYNEBACTERIUM: However, it is sufficiently different from hitherto described Corynebacterium species to be considered as a novel species, for which the name Corynebacterium halotolerans sp. nov. is proposed.

Cell Wall↗

Identification of n-decane oxidation products in Corynebacterium cultures by combined gas chromatography-mass spectrometry.

The gas chromatography-mass spectrometry technique was employed to characterize n-decane oxidation products of Corynebacterium strains 7E1C and 269 (SNAM Progetti collection) after 73 h of incubation at 35 C. Corynebacterium 7E1C accumulated consistent amounts of esters of long chain acids with long chain alcohols, mainly decyldecanoate as well as products with mono- and diterminal carboxylic functions. Corynebacterium 269 yielded 1-decanol and 1-10 decanediol as principal oxidation products.

Alkanes↗

Discovery of a cutinase-producing Pseudomonas sp. cohabiting with an apparently nitrogen-fixing Corynebacterium sp. in the phyllosphere.

A phyllospheric bacterial culture, previously reported to partially replace nitrogen fertilizer (B. R. Patti and A. K. Chandra, Plant Soil 61:419-427, 1981) was found to contain a fluorescent pseudomonas which was identified as Pseudomonas putida and a Corynebacterium sp. The P. putida isolate was found to produce an extracellular cutinase when grown in a medium containing cutin, the polyester structural component of plant cuticle. The Corynebacterium sp. grew on nitrogen-free medium but could not produce cutinase under any induction conditions tested, whereas P. putida could not grow on nitrogen-free medium. When cocultured with the nitrogen-fixing Corynebacterium sp., the P. putida isolate grew in a nitrogen-free medium, suggesting that the former provided fixed N2 for the latter. These results suggest that the two species coexist on the plant surface, with one providing carbon and the other providing reduced nitrogen for their growth. The presence of cutin in the medium induced cutinase production by P. putida. However, unlike the previously studied fungal systems, cutin hydrolysate did not induce cutinase. Thin-layer chromatographic analysis of the products released from labeled apple fruit cutin showed that the extracellular enzyme released all classes of cutin monomers. This enzyme also catalyzed hydrolysis of the model ester substrates, p-nitrophenyl esters of fatty acids, and optimal conditions were determined for a spectrophotometric assay with p-nitrophenyl butyrate as the substrate. It did not hydrolyze triacyl glycerols, indicating that the cutinase activity was not due to a nonspecific lipase. It showed a broad pH optimum between 8.0 and 10.5 with 3H-labeled apple cutin as the substrate.(ABSTRACT TRUNCATED AT 250 WORDS)

Carboxylic Ester Hydrolases↗

Intraspecific variation of unusual phospholipids from Corynebacterium spp. containing a novel fatty acid.

The novel fatty acid trans-9-methyl-10-octadecenoic acid was isolated from the coryneform bacterial strain LMG 3820 (previously misidentified as Arthrobacter globiformis) and identified by spectroscopic methods and chemical derivatization. This fatty acid is attached to the unusual lipid acyl phosphatidylglycerol. Five different species of this lipid type were identified; their structures were elucidated by tandem mass spectrometry and are reported here for the first time. Additionally, we identified three different cardiolipins, two bearing the novel fatty acid. The characteristic 10-methyl-octadecanoic acid was present only in phosphatidylinositol. Because of the unusual fatty acid pattern of strain LMG 3820, the 16S rDNA sequence was determined and showed regions of identity to sequences of Corynebacterium variabilis DSM 20132(T) and DSM 20536. All three strains possessed the novel fatty acid, identifying trans-9-methyl-10-octadecenoic acid as a potential biomarker characteristic for this taxon. Surprisingly, the fatty acid and relative abundances of phospholipids of Corynebacterium sp. strain LMG 3820 were similar to those of the type strain but different from those of Corynebacterium variabilis DSM 20536, although all three strains possessed identical 16S rDNA sequences and strains DSM 20132(T) and DSM 20536 have 90.5% DNA-DNA homology. This is one of the rare cases wherein different organisms with identical 16S rDNA sequences have been observed to present recognizably different fatty acid and lipid compositions. Since methylation of a fatty acid considerably lowers the transition temperature of the corresponding lipid resulting in a more flexible cell membrane, the intraspecific variation in the lipid composition, coinciding with the morphological and Gram stain reaction variability of this species, probably offers an advantage for this species to inhabit different environmental niches.

Corynebacterium↗

Group JK corynebacterium peritonitis in a patient undergoing continuous ambulatory peritoneal dialysis.

We describe a case of peritonitis with isolation of a group JK corynebacterium from the peritoneal effluent in a patient undergoing continuous ambulatory peritoneal dialysis and treated with corticosteroids. Therapy with intraperitoneal vancomycin resulted in a rapid eradication of the organism. However, only 1 month after discontinuation of the 26-day therapy, a second episode of peritonitis with JK corynebacterium occurred. After vancomycin was restarted, the organism disappeared again from the peritoneal fluid, but the patient died a few days later from heart failure apparently unrelated to the infection. Some authors have mentioned the isolation of diphtheroids (without further identification) from peritoneal effluent of continuous ambulatory peritoneal dialysis patients, but to our knowledge, this is the first report of peritonitis associated with JK corynebacterium, an opportunistic organism that must be differentiated from other corynebacteria.

Aged↗

Corynebacterium group D2 as a cause of alkaline-encrusted cystitis: report of four cases and characterization of the organisms.

In four patients with alkaline-encrusted cystitis, Corynebacterium group D2 was isolated from consecutive urine cultures and stones. Encrusted cystitis occurred in bladders harboring inflammatory or tumorous lesions in patients with chronic or recurrent urinary tract infections appearing after surgery or instrumentation. The urease activity of Corynebacterium group D2 and the neutralization of this enzyme by acetohydroxamic acid are shown. Clinical improvement, disappearance of struvite crystals, and decrease of the urine pH were obtained when these bacteria were eliminated from urine samples. Corynebacterium group D2 strains were highly resistant to many antimicrobial agents but were highly susceptible to norfloxacin and vancomycin when tested at two pHs (7.4 and 8.5).

Aged↗

Identification of Corynebacterium glucuronolyticum strains from the urogenital tract of humans and pigs.

Bacterial strains isolated from the genital tracts of humans (predominantly males), semen of boars, and uterine and vaginal secretions of sows were identified as Corynebacterium glucuronolyticum and were compared with the type strains of the recently proposed species Corynebacterium glucuronolyticum and Corynebacterium seminale. The two type strains as well as the clinical strains were shown by DNA-DNA hybridization and sequencing of the 16S rRNA gene to be related at the species level. All strains were classified as C. glucuronolyticum, because this name has nomenclatural priority over C. seminale.

Animals↗