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K Kersters

Publications and source records attributed to K Kersters.

At least 91 records · Page 5Linked to original sources
PubMed1991

Phylogenetic analysis of five medically important Candida species as deduced on the basis of small ribosomal subunit RNA sequences.

The classification of species belonging to the genus Candida Berkhout is problematic. Therefore, we have determined the small ribosomal subunit RNA (srRNA) sequences of the type strains of three human pathogenic Candida species; Candida krusei, C. lusitaniae and C. tropicalis. The srRNA sequences were aligned with published eukaryotic srRNA sequences and evolutionary trees were inferred using a matrix optimization method. An evolutionary tree comprising all available eukaryotic srRNA sequences, including two other pathogenic Candida species, C. albicans and C. glabrata, showed that the yeasts diverge rather late in the course of eukaryote evolution, namely at the same depth as green plants, ciliates and some smaller taxa. The cluster of the higher fungi consists of 10 ascomycetes and ascomycete-like species with the first branches leading to Neurospora crassa, Pneumocystis carinii, Candida lusitaniae and C. krusei, in that order. Next there is a dichotomous divergence leading to a group consisting of Torulaspora delbrueckii, Saccharomyces cerevisiae, C. glabrata and Kluyveromyces lactis and a smaller group comprising C. tropicalis and C. albicans. The divergence pattern obtained on the basis of srRNA sequence data is also compared to various other chemotaxonomic data.

Base Sequence↗
PubMed1990

Is "Campylobacter upsaliensis" an unrecognised cause of human diarrhoea?

For 3 years a filtration system for the isolation of "new" campylobacter was included in the culture protocol of 15,185 stool specimens. "C upsaliensis" was isolated in 99 patients, C jejuni subsp doylei in 4, and C hyointestinalis in 2. "C upsaliensis" was the only organism isolated in 83 patients. Clinical information was available for 77 out of these 83 patients. 92% of the patients had diarrhoea; vomiting and fever were rare (14% and 7%, respectively); the onset was mostly sudden; and the symptoms usually lasted for less than a week. Gross or occult blood was present in a quarter of cases and neutrophils were detected in faecal smears in about a fifth. "C upsaliensis" may be an unrecognised and frequent cause of diarrhoea in man, and selective isolation media should be combined with non-selective isolation systems.

Adult↗
PubMed1990

Interlaboratory comparative study of the numerical analysis of one-dimensional sodium dodecyl sulphate-polyacrylamide gel electrophoretic protein patterns of Campylobacter strains.

Twenty-nine bacterial strains of the genus Campylobacter were examined independently at two collaborating institutes, the National Collection of Type Cultures, London and the Laboratorium voor Microbiologie, Rijksuniversiteit Gent. The one-dimensional polyacrylamide gel electrophoretic protein patterns of the strains were analysed using computerised numerical methods which employed a correlation coefficient and a clustering algorithm. The electrophoretic methods used at the two institutes included both major differences such as gel composition and running conditions and minor differences in buffer composition. Although the algorithm on which similarity and clustering were computed were the same, the detailed treatment of scan patterns differed. The resulting protein patterns in the gels differed markedly in appearance but after numerical analysis the two systems were equally effective in their ability to speciate the strains. There were, however, differences in the relationships between the species defined at the two institutes and these were at least partly due to the different background subtraction methods employed. In conclusion, the portability and reproducibility of the two systems for identification was demonstrated but for definitive classification further standardization may be required.

Bacterial Proteins↗
PubMed1990

Acidovorax, a new genus for Pseudomonas facilis, Pseudomonas delafieldii, E. Falsen (EF) group 13, EF group 16, and several clinical isolates, with the species Acidovorax facilis comb. nov., Acidovorax delafieldii comb. nov., and Acidovorax temperans sp. nov.

Pseudomonas facilis and Pseudomonas delafieldii are inappropriately assigned to the genus Pseudomonas. They belong to the acidovorans rRNA complex in rRNA superfamily III (i.e., the beta subclass of the Proteobacteria). The taxonomic relationships of both of these species, two groups of clinical isolates (E. Falsen [EF] group 13 and EF group 16), and several unidentified or presently misnamed strains were examined by using DNA:rRNA hybridization, numerical analyses of biochemical and auxanographic features and of fatty acid patterns, polyacrylamide gel electrophoresis of cellular proteins, and DNA:DNA hybridization. These organisms form a separate group within the acidovorans rRNA complex, and we propose to transfer them to a new genus, Acidovorax. We describe the following three species in this genus: the type species, Acidovorax facilis (formerly Pseudomonas facilis), with type strain LMG 2193 (= CCUG 2113 = ATCC 11228); Acidovorax delafieldii (for the former Pseudomonas delafieldii and most of the EF group 13 strains), with type strain LMG 5943 (= CCUG 1779 = ATCC 17505); and Acidovorax temperans (for several former Pseudomonas and Alcaligenes strains and most of the EF group 16 strains), with type strain CCUG 11779 (= LMG 7169).

Base Composition↗
PubMed1990

Numerical analysis of electrophoretic protein patterns of 'Achromobacter' group B, E and F strains from human blood.

Thirty-two clinical strains representing 'Achromobacter' groups B, E and F were characterized by one-dimensional SDS-PAGE of cellular proteins. All the strains were isolated from blood samples from hospital patients in the United Kingdom. The protein patterns, which contained 40 to 45 discrete bands, were highly reproducible and were used as the basis for a numerical analysis which included all the protein bands. The 32 'Achromobacter' strains formed two clusters at the 77% S level. The first, phenon 1, included the 28 group B and the two group E strains and the second, phenon 2, contained the two strains of group F. The strains in each phenon were characterized by a clearly distinct pattern of protein bands. Phenon 1 could be further divided at the 87% S level into three subphenons which correlated with differences in the principal bands found between 40.0 and 42.5 kD. Strains of group E clustered with group B strains from which they could not be distinguished by protein patterns. We conclude that high resolution PAGE combined with computerized analysis of protein patterns provides a useful method for the classification of this group of bacteria. Reference strains of each of the PAGE types identified are available from NCTC for inclusion in future studies.

Alcaligenes↗
PubMed1990

Identification and Plant Interaction of a Phyllobacterium sp., a Predominant Rhizobacterium of Young Sugar Beet Plants.

The second most abundant bacterium on the root surface of young sugar beet plants was identified as a Phyllobacterium sp. (Rhizobiaceae) based on a comparison of the results of 39 conventional identification tests, 167 API tests, 30 antibiotic susceptibility tests, and sodium dodecyl sulfate-polyacrylamide gel electrophoretic fingerprints of total cellular proteins with type strains of Phyllobacterium myrsinacearum and Phyllobacterium rubiacearum. It was found on 198 of 1,100 investigated plants between the 2nd and 10th leaf stage on three different fields in Belgium and one field in Spain. Densities ranged from 2 x 10 to 2 x 10 CFU/g of root. Five isolates exerted a broad-spectrum in vitro antifungal activity. DNA-DNA hybridizations showed that Phyllobacterium sp. does not contain DNA sequences that are homologous with the attachment genes chvA, chvB, the transferred-DNA (T-DNA) hormone genes iaaH and ipt from Agrobacterium tumefaciens, iaaM from A. tumefaciens and Pseudomonas savastanoi, or the nitrogenase genes nifHDK from Klebsiella pneumoniae. Phyllobacterium sp. produces indolylacetic acid in in vitro cultures and induces auxinlike effects when cocultivated with callus tissue of tobacco. When Phyllobacterium sp. was transformed with a Ti plasmid derivative, it gained the capacity to induce tumors on Kalanchoe daigremontiana. The potential role of Phyllobacterium sp. in this newly recognized niche is discussed.

Journal Article↗
PubMed1990

Identification of Campylobacter cinaedi isolated from blood and feces of children and adult females.

Five Campylobacter-like organisms isolated from blood and feces were identified by numerical analysis of gel electrophoretic protein profiles and immunotyping as Campylobacter cinaedi. Two of these strains were isolated from adult females; the remaining three strains were isolated from children, two of whom were girls. C. cinaedi has hitherto been isolated only from rectal swabs and blood of homosexual and bisexual males with gastrointestinal symptoms. The results presented extend our knowledge of the features and the habitat of C. cinaedi.

Adult↗
PubMed1989

Identification of EF group 22 campylobacters from gastroenteritis cases as Campylobacter concisus.

EF (E. Falsen) group 22, a group of Campylobacter strains sorted out by routine immunotyping among unidentified or misidentified human nonoral clinical specimens, was characterized by numerical analysis of gel electrophoretic protein profiles and immunotyping. The protein electrophoretic and immunotyping analyses, DNA:DNA hybridizations, and the DNA base composition demonstrated unambiguously that all EF group 22 strains belong to Campylobacter concisus. EF group 22 strains have DNA binding values of at least 42% with the type strain of C. concisus, showing a considerable degree of genomic heterogeneity. The isolation from blood, esophagus, stomach, duodenum, and feces of humans in association with different gastrointestinal disorders considerably extends the clinical significance of this species. Our results indicate that sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunotyping are excellent tools for the identification of the fastidious C. concisus strains and relatives.

Adult↗
PubMed1989

Investigation of the ability of newer beta-lactam antibiotics to select resistant mutants from Serratia marcescens after mutagenesis with nitrosoguanidine.

Resistant mutants could easily be selected from a nitrosoguanidine-treated culture of Serratia marcescens with piperacillin, cefotaxime, cefoxitin, cefotetan, latamoxef (moxalactam) and aztreonam. Imipenem on the other hand was significantly less effective in mutant selection. Resistant clones broadly fell into two distinct classes. Most mutants did not show increased beta-lactamase; their resistance seemed to be due to changed outer membrane proteins. Other mutants had strongly increased cephalosporinase activity, although the derepression was only partial. Piperacillin, cefotaxime and aztreonam preferentially selected the derepressed phenotype, whereas mutants selected with cefoxitin, cefotetan, moxalactam and imipenem were exclusively of the non-derepressed phenotype. There was a significant degree of cross-resistance between the beta-lactam antibiotics except imipenem which was only slightly less active against the membrane-altered mutants.

Anti-Bacterial Agents↗
PubMed1986

Identification and grouping of Clostridium botulinum strains by numerical analysis of their electrophoretic protein patterns.

Strains of Clostridium botulinum type A, type E and both non-proteolytic and proteolytic types B and F were characterized by their electrophoretic protein patterns. As the protein pattern changes during sporulation, special attention was paid to the prevention of sporulation by selecting an appropriate medium (Strasdine's medium plus 1% w/v glucose) and a scheme of repeated subculturing. Ribosomal proteins, evolutionarily conservative and hence relatively similar in all types of bacteria, were removed to optimize the resolving power of the electrophoretic technique. Protein patterns were compared by computing correlation coefficients of normalized densitometric tracings. The method is highly reproducible and its resolving power is high: all protein patterns found were specific. The strains tested fall into two main groups: the proteolytic and the non-proteolytic cluster. Type A strains form a separate subgroup within the proteolytic cluster, the same applies to type E strains within the non-proteolytic group. Although time-consuming for spore-forming bacteria, this method is, to our knowledge, the only technique that recognizes individual strains of Cl. botulinum. For non-spore-forming micro-organisms the method is certainly much simpler and hence even more valuable.

Bacterial Proteins↗
PubMed1984

Differentiation between Xanthomonas campestris pv. oryzae, Xanthomonas campestris pv. oryzicola and the bacterial 'brown blotch' pathogen on rice by numerical analysis of phenotypic features and protein gel electrophoregrams.

Thirty-five Xanthomonas campestris pv. oryzae, fourteen X. campestris pv. oryzicola strains and six 'brown blotch' pathogens of rice, all of different geographical origin, were studied by numerical analysis of 133 phenotype features and gel electrophoregrams of soluble proteins, %G + C determinations and DNA:rRNA hybridizations. The following conclusions were drawn. (i) The Xanthomonas campestris pathovars oryzae and oryzicola display clearly distinct protein patterns on polyacrylamide gels and can be differentiated from each other by four phenotype tests. (ii) Both pathovars are indeed members of Xanthomonas which belongs to a separate rRNA branch of the second rRNA superfamily together with the rRNA branches of Pseudomonas fluorescens, Marinomonas, Azotobacter, Azomonas and Frateuria. (iii) 'Brown blotch' strains are considerably different from X. campestris pv. oryzae and oryzicola. They are not members of the genus Xanthomonas, but are more related to the generically misnamed. Flavobacterium capsulatum, Pseudomonas paucimobilis, Flavobacterium devorans and 'Pseudomonas azotocolligans' belonging in the fourth rRNA superfamily. (iv) No correlation was found between the virulence, pathogenic groups or geographical distribution of X. campestris pv. oryzae or oryzicola strains and any phenotypic or protein electrophoretic property or clustering.

Base Composition↗
PubMed1981

Gluconobacters from honey bees.

Fifty-six Gluconobacter strains and one Acetobacter strain were isolated from honey bees and their environment in three different regions in Belgium and identified phenotypically. Polyacrylamide gel electrophoresis of the soluble cell proteins showed that two different types exist within the Gluconobacter isolates: strains from type A were found in samples of the three regions, whereas strains from type B were only isolated in two of the three regions. Both types could occur in bees from the same region, from several hives of one bee keeper and from one hive. Strains from type A were almost identical with collection strain G. oxydans subsp. suboxydans NCIB 9018, whereas strains from type B constituted a new protein electrophoretic type within the genus Gluconobacter. Although Gluconobacter is apparently associated with honey bees, it is not known whether it is important or required for the bees or any hive product.

Animals↗
PubMed1976

L-Sorbose metabolism in Agrobacterium tumefaciens.

The pathway of L-sorbose metabolism in Agrobacterium tumefaciens strain B6 was determined to be: L-sorbose leads to D-glucitol (sorbitol) leads to D-fructose leads to D-fructose-6-phosphate leads to D-glucose-6-phosphate. The reduction of L-sorbose and the oxidation of D-glucitol were mediated by NADPH- and NAD+-linked oxidoreductases, respectively. The intermediates, D-glucitol and D-fructose, were isolated from in vitro reaction mixtures by column chromatography on Dowex 1-borate, and identified enzymatically. D-Fructose was identified chemically by its 1H-NMR spectrum and the IR spectrum and the melting point of the fructosazone. D-Glucitol was characterized chemically by the melting point and the IR spectrum of its hexaacetate. A. tumefaciens ICPB TT111, a representative of another genetic race of Agrobacterium, lacked L-sorbose reductase and therefore failed to grow on L-sorbose; it grew normally on D-glucitol.

Alcohol Oxidoreductases↗