Biomedical subjects

Richard Christen

Publications and source records attributed to Richard Christen.

At least 37 records · Page 2Linked to original sources

PubMed2004

Belliella baltica gen. nov., sp. nov., a novel marine bacterium of the Cytophaga-Flavobacterium-Bacteroides group isolated from surface water of the central Baltic Sea.

Two bacterial isolates from the Baltic Sea, BA1 and BA134T, were characterized for their physiological and biochemical features, fatty acid profiles and phylogenetic position based on 16S rRNA gene sequences. The strains were isolated from surface water of the central Baltic Sea during the decay of a plankton bloom. Phylogenetic analysis of their 16S rRNA gene sequences revealed a clear affiliation to the family 'Flexibacteriaceae' and showed highest sequence similarity (91%) to Cyclobacterium marinum. The G+C content of the DNA was 35.4 mol%. The strains were pink-coloured due to carotinoids, Gram-negative, rod-shaped and catalase- and oxidase-positive. Growth was observed at 0-6% salinity, with good growth at 0-3%. Temperature for growth was 4-37 degrees C, with an optimum around 25 degrees C. The fatty acid profiles were dominated by branched-chain fatty acids (70%), with a high abundance of iso-C(15:0) (29-33%), iso-C(17:1)omega9c (7-10%) and C(17:1)omega6c (5-10%). According to their morphology, physiology, fatty acid composition, 16S rRNA gene sequences and DNA-DNA similarity, on one hand, the described bacteria are considered to be members of the same novel species; on the other hand, they are suggested as a novel genus of the family 'Flexibacteriaceae'. To honour the late aquatic microbiologist Russell T. Bell, the name Belliella baltica gen. nov, sp. nov. is suggested for the Baltic Sea isolates, for which the type strain is BA134T (=DSM 15883T=LMG 21964T=CIP 108006T).

Bacteroides↗

PubMed2004

Formosa algae gen. nov., sp. nov., a novel member of the family Flavobacteriaceae.

Four light-yellow-pigmented, Gram-negative, short-rod-shaped, non-motile isolates were obtained from enrichment culture during degradation of the thallus of the brown alga Fucus evanescens. The isolates studied were chemo-organotrophic, alkalitolerant and mesophilic. Polar lipids were analysed and phosphatidylethanolamine was the only phospholipid identified. The predominant cellular fatty acids were 15 : 0, i15 : 0, ai15 : 0, i15 : 1 and 15 : 1(n-6). The DNA G+C contents of the four strains were 34.0-34.4 mol%. The level of DNA relatedness of the four isolates was conspecific (88-98 %), indicating that they belong to the same species. The 16S rDNA sequence of strain KMM 3553(T) was determined. Phylogenetic analysis revealed that KMM 3553(T) formed a distinct phyletic line in the phylum Bacteroidetes, class Flavobacteria in the family Flavobacteriaceae and that, phylogenetically, this strain could be placed almost equidistant from the genera Gelidibacter and Psychroserpens (16S rRNA gene sequence similarities of 94 %). On the basis of significant differences in phenotypic and chemotaxonomic characteristics, it is suggested that the isolates represent a novel species in a new genus; the name Formosa algae gen. nov., sp. nov. is proposed. The type strain is KMM 3553(T) (=CIP 107684(T)).

Base Composition↗

PubMed2004

Vibrio gallicus sp. nov., isolated from the gut of the French abalone Haliotis tuberculata.

Five alginolytic, facultatively anaerobic, non-motile bacteria were isolated from the gut of the abalone Haliotis tuberculata. Phylogenetic analyses based on 16S rDNA data indicated that these strains are related to Vibrio wodanis, Vibrio salmonicida, Vibrio logei and Vibrio fischeri (but with <97 % 16S rRNA gene sequence similarity). DNA-DNA hybridization and fluorescence amplified fragment length polymorphism fingerprinting demonstrated that the five strains constituted a single species that was different from all currently known vibrios. The name Vibrio gallicus sp. nov. (type strain, CIP 107863(T)=LMG 21878(T)=HT2-1(T); DNA G+C content, 43.6-44.3 mol%) is proposed for this novel taxon. Several phenotypic features were disclosed that discriminated V. gallicus from other Vibrio species: V. gallicus can be differentiated from Vibrio halioticoli on the basis of four traits (beta-galactosidase test and assimilation of three carbon compounds) and from Vibrio superstes by 16 traits.

Animals↗

PubMed2004

Brevibacterium celere sp. nov., isolated from degraded thallus of a brown alga.

Two whitish yellow, Gram-positive, non-motile, aerobic bacteria were isolated from enrichment culture during degradation of the thallus of the brown alga Fucus evanescens. The bacteria studied were chemo-organotrophic, mesophilic and grew well on nutrient media containing up to 15 % (w/v) NaCl. The DNA G+C content was 61 mol%. The two isolates exhibited a conspecific DNA-DNA relatedness value of 98 %, indicating that they belong to the same species. A comparative analysis of 16S rRNA gene sequences revealed that strain KMM 3637(T) formed a distinct phyletic lineage in the genus Brevibacterium (family Brevibacteriaceae, class Actinobacteria) and showed the highest sequence similarity (about 97 %) to Brevibacterium casei. DNA-DNA hybridization experiments demonstrated 45 % binding with the DNA of B. casei DSM 20657(T). Physiological and chemotaxonomic characteristics (meso-diaminopimelic acid in the peptidoglycan, major cellular fatty acids 15 : 0ai and 17 : 0ai) of the bacteria studied were consistent with the genomic and phylogenetic data. On the basis of the results of this study, a novel species, Brevibacterium celere sp. nov., is proposed. The type strain is KMM 3637(T) (=DSM 15453(T)=ATCC BAA-809(T)).

Aerobiosis↗

PubMed2004

Phylogenetic relationships among marine Alteromonas-like proteobacteria: emended description of the family Alteromonadaceae and proposal of Pseudoalteromonadaceae fam. nov., Colwelliaceae fam. nov., Shewanellaceae fam. nov., Moritellaceae fam. nov., Ferrimonadaceae fam. nov., Idiomarinaceae fam. nov. and Psychromonadaceae fam. nov.

The phylogenetic relationships among marine Alteromonas-like bacteria of the genera Alteromonas, Pseudoalteromonas, Glaciecola, Thalassomonas, Colwellia, Idiomarina, Oceanimonas, Oceanisphaera, Shewanella, Moritella, Ferrimonas, Psychromonas and several other genera of the 'Gammaproteobacteria' were studied. Results of 16S rRNA gene sequence analyses revealed that some members of these genera formed several coherent groups at the family level. Characteristic signature oligonucleotides for studied taxa were defined. Signature positions are divided into three classes: (i) single compensatory mutations, (ii) double compensatory mutations and (iii) mutations affecting nucleotides not paired in the secondary structure. The 16S rRNA gene sequence similarity level within genera was 93 % or above. This value can be a useful additional criterion for genus discrimination. On the basis of this work and previous polyphasic taxonomic studies, the circumscription of the family Alteromonadaceae is limited to the genera Alteromonas and Glaciecola and the creation is proposed of the families Pseudoalteromonadaceae fam. nov. to accommodate bacteria of the genera Pseudoalteromonas and Algicola gen. nov. (formerly Pseudoalteromonas bacteriolytica) and Colwelliaceae fam. nov. to accommodate bacteria of the genera Colwellia and Thalassomonas. Bacteria of the genera Oceanimonas and Oceanisphaera formed a robust cluster and shared common signature oligonucleotides. Because of deep branching and lack of association with any other genus, the following families are proposed that include single genera: Idiomarinaceae fam. nov., Psychromonadaceae fam. nov., Moritellaceae fam. nov., Ferrimonadaceae fam. nov. and Shewanellaceae fam. nov. Finally, this study also revealed that [Hyphomicrobium] indicum should be reclassified as Photobacterium indicum comb. nov.

Alteromonas↗

PubMed2004

Characterization of Pseudoalteromonas distincta-like sea-water isolates and description of Pseudoalteromonas aliena sp. nov.

Seven melanogenic Pseudoalteromonas distincta-like strains, KMM 3562T, KMM 3536, KMM 3537, KMM 3538, KMM 3539, KMM 3615 and KMM 3629, which expressed tyrosinases were isolated from sea-water samples collected from different locations in Amursky Bay (Sea of Japan, Pacific Ocean) and characterized to clarify their taxonomic position. By 16S rRNA gene sequence analysis, the bacteria were shown to belong to the genus Pseudoalteromonas. The G + C content of the DNAs of the strains was 41-43 mol%. The level of DNA similarity among these strains was conspecific (92-97 %), indicating that they represented a single genospecies. However, DNA from the strains isolated from sea water showed only 63-65 % genetic relatedness with the DNA of the type strain P. distincta. The novel organisms grew mainly between 4 and 30 degrees C, were neutrophilic and slightly halophilic (four strains had a narrow range of growth between 3 and 6 % NaCl, w/v), were haemolytic and cytotoxic and were able to degrade starch, gelatin and Tween 80. The predominant fatty acids, including 16 : 0, 16 : 1omega7, 17 : 1omega7 and 18 : 1omega7, were typical of the genus Pseudolateromonas. The phylogenetic, genetic and physiological properties of the seven strains placed them within a novel species, Pseudoalteromonas aliena sp. nov., the type strain of which is SW19T (= KMM 3562T = LMG 22059T).

Anti-Bacterial Agents↗

PubMed2004

Aquiflexum balticum gen. nov., sp. nov., a novel marine bacterium of the Cytophaga-Flavobacterium-Bacteroides group isolated from surface water of the central Baltic Sea.

A bacterial isolate from the Baltic Sea, BA160(T), was characterized for its physiological and biochemical features, fatty acid profile, G+C content and phylogenetic position based on 16S rRNA gene sequences. The strain was isolated from the surface water of the central Baltic Sea during the decay of a plankton bloom. Phylogenetic analyses of the 16S rRNA gene sequence revealed a clear affiliation with the family 'Flexibacteraceae', and showed the closest phylogenetic relationship with the species Belliella baltica and Cyclobacterium marinum. The G+C content of the DNA was 38.4 mol%. The strain was red-coloured due to carotenoids, Gram-negative, rod-shaped, and catalase- and oxidase-positive. Growth was observed at salinities from 0 to 6 %, with an optimum around 1.5 %. Temperature for growth ranged from 4 to 40 degrees C, with an optimum around 30 degrees C. The fatty acids were dominated by branched-chain fatty acids (>87 %), with a high abundance of iso-C(15 : 0) (23 %) and anteiso-C(15 : 0) (19 %). According to its morphology, physiology, fatty acid composition, G+C content and 16S rRNA gene sequence, strain BA160(T) is considered to represent a new genus of the family 'Flexibacteraceae'. Due to its aquatic origin, the name Aquiflexum balticum gen. nov, sp. nov. is suggested for the type species (type strain, BA160(T)=DSM 16537(T)=LMG 22565(T)=CIP 108445(T)) of the new genus.

Bacterial Typing Techniques↗

PubMed2004

Establishment of a real-time PCR-based approach for accurate quantification of bacterial RNA targets in water, using Salmonella as a model organism.

Quantitative PCR (Q-PCR) is a fast and efficient tool to quantify target genes. In eukaryotic cells, quantitative reverse transcription-PCR (Q-RT-PCR) is also used to quantify gene expression, with stably expressed housekeeping genes as standards. In bacteria, such stable expression of housekeeping genes does not occur, and the use of DNA standards leads to a broad underestimation. Therefore, an accurate quantification of RNA is feasible only by using appropriate RNA standards. We established and validated a Q-PCR method which enables the quantification of not only the number of copies of target genes (i.e., the number of bacterial cells) but also the number of RNA copies. The genes coding for InvA and the 16S rRNA of Salmonella enterica serovar Typhimurium were selected for the evaluation of the method. As DNA standards, amplified fragments of the target genes were used, whereas the same DNA standards were transcribed in vitro for the development of appropriate RNA standards. Salmonella cultures and environmental water samples inoculated with bacteria were then employed for the final testing. Both experimental approaches led to a sensitive, accurate, and reproducible quantification of the selected target genes and RNA molecules by Q-PCR and Q-RT-PCR. It is the first time that RNA standards have been successfully used for a precise quantification of the number of RNA molecules in prokaryotes. This demonstrates the potential of this approach for determining the presence and metabolic activity of pathogenic bacteria in environmental samples.

Bacterial Proteins↗

PubMed2004

Development and application of a real-time PCR approach for quantification of uncultured bacteria in the central Baltic Sea.

We have developed a highly sensitive approach to assess the abundance of uncultured bacteria in water samples from the central Baltic Sea by using a noncultured member of the "Epsilonproteobacteria" related to Thiomicrospira denitrificans as an example. Environmental seawater samples and samples enriched for the target taxon provided a unique opportunity to test the approach over a broad range of abundances. The approach is based on a combination of taxon- and domain-specific real-time PCR measurements determining the relative T. denitrificans-like 16S rRNA gene and 16S rRNA abundances, as well as the determination of total cell counts and environmental RNA content. It allowed quantification of T. denitrificans-like 16S rRNA molecules or 16S rRNA genes as well as calculation of the number of ribosomes per T. denitrificans-like cell. Every real-time measurement and its specific primer system were calibrated using environmental nucleic acids obtained from the original habitat for external standardization. These standards, as well as the respective samples to be measured, were prepared from the same DNA or RNA extract. Enrichment samples could be analyzed directly, whereas environmental templates had to be preamplified with general bacterial primers before quantification. Preamplification increased the sensitivity of the assay by more than 4 orders of magnitude. Quantification of enrichments with or without a preamplification step yielded comparable results. T. denitrificans-like 16S rRNA molecules ranged from 7.1 x 10(3) to 4.4 x 10(9) copies ml(-1) or 0.002 to 49.7% relative abundance. T. denitrificans-like 16S rRNA genes ranged from 9.0 x 10(1) to 2.2 x10(6) copies ml(-1) or 0.01 to 49.7% relative abundance. Detection limits of this real-time-PCR approach were 20 16S rRNA molecules or 0.2 16S rRNA gene ml(-1). The number of ribosomes per T. denitrificans-like cell was estimated to range from 20 to 200 in seawater and reached up to 2,000 in the enrichments. The results indicate that our real-time PCR approach can be used to determine cellular and relative abundances of uncultured marine bacterial taxa and to provide information about their levels of activity in their natural environment.

Bacteria↗

PubMed2003

Shewanella fidelis sp. nov., isolated from sediments and sea water.

Two marine bacterial strains, KMM 3582T and KMM 3589, isolated respectively from sediments of the South China Sea and sea water of the Sea of Japan, have been characterized. Comparative 16S rDNA sequence-based phylogenetic analysis placed the two strains in a separate branch of the gamma-Proteobacteria within the members of the genus Shewanella. KMM 3582T showed the highest similarity (97.1 and 97.4%, respectively) to Shewanella pealeana and Shewanella gelidimarina. The G + C contents of the DNAs of the two strains studied were 45.0 mol%. The level of DNA-DNA relatedness between the two strains was 82%, indicating that they represent a single genospecies. These organisms were slightly pinkish, Gram-negative, polarly flagellated, facultatively anaerobic, mesophilic (with temperature range from 4 to 30 degrees C), neutrophilic and haemolytic and were able to degrade alginate, gelatin and DNA. The novel organisms were susceptible to gentamicin, lincomycin, oleandomycin, streptomycin and polymyxin. The predominant fatty acids were characteristic for shewanellae: 13 : 0-i, 15 : 0-i, 16 : 0 and 16 : 1omega7. Eicosapentaenoic acid, 20 : 5omega3, was not detected. Phylogenetic evidence, together with phenotypic characteristics, showed that the two bacteria constitute a novel species of the genus Shewanella. The name Shewanella fidelis sp. nov. is proposed, with the type strain KMM 3582T (=LMG 20551T =ATCC BAA-318T).

Anti-Bacterial Agents↗

PubMed2003

Idiomarina baltica sp. nov., a marine bacterium with a high optimum growth temperature isolated from surface water of the central Baltic Sea.

Two bacterial strains isolated from the Baltic Sea, OS145T and OS146, were characterized on the basis of their physiological and biochemical features, their fatty acid profiles and their phylogenetic position based on 16S rDNA sequence analyses. The strains were isolated from the upperoxic water column of the central Baltic Sea. Phylogenetic analyses of the 16S rDNA gene sequences revealed a clear affiliation of the novel strains with members of the genus Idiomarina, of the Gammaproteobacteria. Closest sequence similarity was seen with Idiomarina abyssalis and Idiomarina zobellii (95-96%). The mean G + C content of the DNA of strains OS145T and OS146 was 49.7 mol%. Both strains were non-pigmented, Gram-negative, polarly flagellated organisms that were strictly aerobic. Growth of the strains was observed at salinities ranging from 0.8 to 10% NaCl. Temperature range for growth was rather broad and high for marine bacteria: both strains grew between 8 and 46 degrees C, showed good growth between 20 and 44 degrees C, and had an optimum between 30 and 40 degrees C. The fatty acids of the two strains were dominated by iso-branched fatty acids (54-80%), with a high abundance of C15:0 iso (36%), C16:1 omega7c, C17:o iso and C17:1 iso omega9c. Growth temperature (8-40 degrees C) influenced the fatty acid composition of the strains in a way that the content of iso-branching fatty acids increased with increasing temperatures, while the mono-unsaturated fattyacids increased with decreasing temperatures. Salinity (1.7-10% NaCl) had only a minor effect on the fatty acid composition. According to their morphology, physiology, fatty acid composition and 16S rDNA sequences, strains OS145T and OS146 fitted well into the genus Idiomarina, but could be easily distinguished from the recognized species of the genus. Because of their unique nature, it is proposed that the strains isolated from the Baltic Sea represent a novel species, for which the name Idiomarina baltica (type strain OS145T =DSM 15154T =LMG 21691T) is proposed.

Baltic States↗

PubMed2003

Elevation of three subspecies of Pectobacterium carotovorum to species level: Pectobacterium atrosepticum sp. nov., Pectobacterium betavasculorum sp. nov. and Pectobacterium wasabiae sp. nov.

A collection of 42 strains belonging to the five subspecies of Pectobacterium carotovorum (subspecies atrosepticum, betavasculorum, carotovorum, odoriferum and wasabiae) and 11 reference and type strains of biovars of Pectobacterium chrysanthemi, Pectobacterium cacticidum and Brenneria paradisiaca were studied by DNA-DNA hybridization, numerical taxonomy of 120 phenotypic characteristics, serology and new phylogenetic analysis of previously reported sequences from a database of aligned 16S rDNA sequences. The P. carotovorum subspecies formed a clade according to neighbour-joining methods, but they formed two paraphyletic clusters according to maximum-likelihood and maximum-parsimony. However, phylogenetic analysis of 16S rDNA sequences alone is not sufficient to justify generic differentiation and therefore, it is proposed to retain the P. carotovorum subspecies in the genus Pectobacterium. The strains of P. carotovorum were distributed in four genomospecies: genomospecies 1, harbouring all strains of subsp. atrosepticum, genomospecies 2, including the strains of subsp. betavasculorum isolated from sugar beet, sunflower, potato, hyacinth and artichoke, genomospecies 3, clustering all strains of subsp. wasabiae isolated from wasabi in Japan, and genomospecies 4, gathering together strains of subsp. carotovorum and strains of subsp. odoriferum. Four strains of P. carotovorum subsp. carotovorum remained unclustered. Biochemical criteria, deduced from a numerical taxonomy study of phenotypic characteristics and serological reactions, allowed discrimination of strains belonging to the four genomospecies. Thus, it is proposed that three genomospecies be elevated to species level as Pectobacterium atrosepticum sp. nov. (type strain CFBP 1526T =LMG 2386T =NCPPB 549T =ICMP 1526T), Pectobacterium betavasculorum sp. nov. (type strain CFBP 2122T =LMG 2464T =NCPPB 2795T =ICMP 4226T) and Pectobacterium wasabiae sp. nov. (type strain CFBP 3304T =LMG 8404T =NCPPB 3701T =ICMP 9121T). Only two subspecies are maintained within P. carotovorum, subsp. carotovorum (type strain CFBP 2046T =LMG 2404T =NCPPB 312T =ICMP 5702T) and subsp. odoriferum (type strain CFBP 1878T =LMG 5863T =NCPPB 3839T = ICMP 11553T), for which discriminating tests are available.

Enterobacteriaceae↗

PubMed2003

Ramlibacter tataouinensis gen. nov., sp. nov., and Ramlibacter henchirensis sp. nov., cyst-producing bacteria isolated from subdesert soil in Tunisia.

Ramlibacter gen. nov. is proposed for two aerobic, chemo-organotrophic, cyst-producing soil bacterial strains. These bacteria are Gram-negative, non-flagellated rods or cysts, isolated from subdesert soil in Tataouine, Tunisia. Phylogenetic analyses of the rrs sequences of the two strains showed that they do not constitute a robust clade at the genus level with any previously described bacteria and that they are a deep branch of a clade also grouping the genera Acidovorax and Hydrogenophaga within the beta-Proteobacteria. They belong to two different species, as verified by DNA-DNA hybridization (23.5% reassociation). The type species of the genus is Ramlibacter tataouinensis sp. nov., with the type strain TTB310T (=DSM 14655T =ATCC BAA-407T =LMG 21543T). The second species is Ramlibacter henchirensis sp. nov., with the type strain TMB834T (=DSM 14656T =ATCC BAA-408T =LMG 21542T). The G + C contents of R. tataouinensis and R. henchirensis are 69.6 and 66.6 mol%, respectively.

Betaproteobacteria↗

PubMed2003

Vibrio superstes sp. nov., isolated from the gut of Australian abalones Haliotis laevigata and Haliotis rubra.

Five alginolytic, facultatively anaerobic, non-motile bacteria were isolated from the gut of abalones Haliotis laevigata and Haliotis rubra. Phylogenetic analyses based on 16S rDNA data indicated that these strains are related closely to Vibrio halioticoli (98 % 16S rDNA sequence similarity). DNA-DNA hybridization and fluorescent amplified fragment length polymorphism fingerprinting demonstrated that the five strains constituted a single species that was different from all currently known vibrios. The name Vibrio superstes sp. nov. (type strain, LMG 21323(T)=IAM 15009(T)=G3-29(T); DNA G+C content, 48.0-48.9 mol%) is proposed to encompass this novel taxon. Several phenotypic features were disclosed that discriminate V. superstes from other Vibrio species: V. superstes sp. nov. and V. halioticoli can be differentiated on the basis of 17 traits (indole production, beta-galactosidase test and assimilation of 15 carbon compounds).

Animals↗

PubMed2003

Shewanella waksmanii sp. nov., isolated from a sipuncula (Phascolosoma japonicum).

Two marine bacterial strains, KMM 3823(T) and KMM 3836, isolated from a sipuncula (Phascolosoma japonicum), a common inhabitant of Troitsa Bay in the Gulf of Peter the Great (Sea of Japan), were studied. Comparative 16S rRNA gene sequence-based phylogenetic analysis placed these bacteria into a separate branch of the 'Gammaproteobacteria' within members of the genus SHEWANELLA: KMM 3823(T) showed the highest similarity (96.6 %) with Shewanella fidelis. The DNA G+C contents of the two strains studied were 43.0 mol%. The level of DNA homology between these two strains was conspecific (93 %), indicating that they represent a single genospecies. These organisms were greenish-brown, Gram-negative, polarly flagellated, facultatively anaerobic, mesophilic (temperature range 4-30 degrees C), neutrophilic, haemolytic and were able to degrade elastin, gelatin and DNA. They were susceptible to ampicillin, carbenicillin, gentamicin and kanamycin. The predominant fatty acids were characteristic for shewanellas: 13 : 0-i, 15 : 0-i and 16 : 1(n-7); up to 6.7 % of eicosapentaenoic fatty acid, 20 : 5(n-3), was produced during growth at 28 degrees C. Phylogenetic evidence, confirmed by DNA hybridization and phenotypic characteristics revealed that the two bacteria studied constitute a new species, Shewanella waksmanii sp. nov., the type strain of which is KMM 3823(T) (=CIP 107701(T)=ATCC BAA-643(T)).

Animals↗

PubMed2003

Marinobacter excellens sp. nov., isolated from sediments of the Sea of Japan.

Five strains of halophilic, Gram-negative marine bacteria (KMM 3809(T), KMM 3814, KMM 3815, KMM 3817 and KMM 3818) were isolated from sediments collected from Chazhma Bay, Sea of Japan. Phylogenetic 16S rRNA gene sequence-based analysis placed these bacteria in a clade within the genus Marinobacter in the gamma-Proteobacteria. KMM 3809(T) showed highest 16S rRNA gene sequence similarity of 97.3 % to Marinobacter litoralis and 96.9 % to Marinobacter hydrocarbonoclasticus and Marinobacter aquaeolei. DNA-DNA hybridization between the five isolates was at the conspecific level (94-96 %) and that among the closest phylogenetic neighbours ranged from 45.0 to 62.5 %. The new organisms were susceptible to polymyxin. Predominant fatty acids were C(16 : 0), C(16 : 1)omega9c, C(16 : 1)omega7c and C(18 : 1)omega9c. Phylogenetic evidence, along with phenotypic and genotypic characteristics, showed that the bacteria constituted a novel species of the genus Marinobacter. The name Marinobacter excellens sp. nov. is proposed for this species, with the type strain KMM 3809(T) (=CIP 107686(T)).

Alteromonadaceae↗

PubMed2002

Pseudoalteromonas issachenkonii sp. nov., a bacterium that degrades the thallus of the brown alga Fucus evanescens.

Eleven non-pigmented strains of gram-negative, aerobic, marine bacteria with polar flagella were isolated from the thallus of the brown alga Fucus evanescens collected in the Kraternaya Bight of the Kurile Islands in the Pacific Ocean. These organisms were conspecific and exhibited high levels of genetic relatedness (up to 91%). The G+C contents of the DNAs of these strains were 42.9-43.3 mol%. These halophilic bacteria had bacteriolytic, proteolytic and haemolytic activities and degraded algal polysaccharides, synthesizing a number of glycoside hydrolases (fucoidanases, laminaranases, alginases, agarases, pullulanases, beta-glucosidases, beta-galactosidases, beta-N-acetylglucosaminidases and beta-xylosidases). By 16S rDNA analysis, the bacteria were shown to belong to the genus Pseudoalteromonas, a member of the gamma-subclass of the Proteobacteria. DNA from the strains isolated from the brown alga showed 27-54% genetic relatedness with respect to DNAs of other type strains of the genus Pseudoalteromonas. The phenotypic characteristics, together with the genetic evidence, indicate that this group of epiphytic bacteria represents a distinct species, Pseudoalteromonas issachenkonii sp. nov., for which the type strain is KMM 3549T (= LMG 19697T = CIP 106858T).

Gammaproteobacteria↗

PubMed2002

Pseudoalteromonas ruthenica sp. nov., isolated from marine invertebrates.

On the basis of phenotypic and genotypic characteristics and analysis of 165 rRNA sequences, a novel species belonging to the genus Pseudoalteromonas is described. Two pale-orange-pigmented strains, KMM 300T and KMM 290, isolated respectively from a mussel, Crenomytilus grayanus, and a scallop, Patinopecten yessoensis, are marine, gram-negative, aerobic, rod-shaped bacteria that produce a number of antimicrobial compounds. The strains are able to degrade gelatin, elastin, starch, DNA and Tween 80. Chitin and agar are not degraded. The isolates from marine invertebrates grew at NaCl concentrations of 1-9% and a temperature range of 10-35 degrees C and did not utilize most of the wide range of carbohydrates tested, with the exception of D-glucose, cellobiose and sucrose. The DNA G+C content was 48.4-48.9 mol%. The level of DNA homology of the two strains was 98%. DNA from the strains isolated from marine invertebrates showed 5-15% genetic relatedness to the DNA of other type strains of the genus Pseudoalteromonas. 16S rRNA analysis indicated a clear affiliation of the novel bacteria to other species of the genus. The strains are assigned to a novel species, Pseudomonas ruthenica sp. nov., with the type strain KMM 300T (= LMG 19699T = CIP 106857T).

Animals↗