580 research outputs found

    Reclassification of <i>Vibrio hollisae</i> as <i>Grimontia hollisae</i> gen. nov., comb. nov.

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    The taxonomic positions of three representative strains of Vibrio hollisae (LMG 17719T, LMG 21416 and LMG 21538) were investigated by means of 16S rDNA sequences and phenotypic data. V. hollisae strains (GenBank/EMBL accession nos AJ514909–AJ514911) shared 99·5 % 16S rDNA sequence similarity, but had only 94·6 % similarity to their closest phylogenetic neighbour, Enterovibrio norvegicus. 16S rDNA sequence similarity of V. hollisae and Vibrio cholerae was only 91 %. These results suggest that V. hollisae should be placed into a novel genus, for which the name Grimontia gen. nov. is proposed

    <i>Vibrio kanaloae</i> sp. nov., <i>Vibrio pomeroyi</i> sp. nov. and <i>Vibrio chagasii</i> sp. nov., from sea water and marine animals

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    The taxonomic position of the fluorescent amplified fragment length polymorphism fingerprinting groups A46 (five isolates), A51 (six isolates), A52 (five isolates) and A53 (seven isolates) obtained in a previous study were further analysed through a polyphasic approach. The 23 isolates were phylogenetically related to Vibrio splendidus, but DNA-DNA hybridization experiments proved that they belong to three novel species. Chemotaxonomic and phenotypic analyses further disclosed several features that differentiate between the 23 isolates and known Vibrio species. The names Vibrio kanaloae sp. nov. (type strain LMG 20539T=CAIM 485T; EMBL accession no. AJ316193; G+C content 44·7 mol%), Vibrio pomeroyi sp. nov. (type strain LMG 20537T=CAIM 578T; EMBL accession no. AJ491290; G+C content 44·1 mol%) and Vibrio chagasii sp. nov. (type strain LMG 21353T=CAIM 431T; EMBL accession no. AJ316199; G+C content 44·6 mol%) are respectively proposed to encompass the five isolates of A46, the six isolates of A51 and the 12 isolates of A52/A53. The three novel species can be distinguished from known Vibrio species by several phenotypic features, including utilization and fermentation of various carbon sources, -galactosidase activity and fatty acid content (particularly of 12 : 0, 14 : 0, 14 : 0 iso and 16 : 0 iso)

    Use of <i>recA</i> as an alternative phylogenetic marker in the family <i>Vibrionaceae</i>

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    This study analysed the usefulness of recA gene sequences as an alternative phylogenetic and/or identification marker for vibrios. The recA sequences suggest that the genus Vibrio is polyphyletic. The high heterogeneity observed within vibrios was congruent with former polyphasic taxonomic studies on this group. Photobacterium species clustered together and apparently nested within vibrios, while Grimontia hollisae was apart from other vibrios. Within the vibrios, Vibrio cholerae and Vibrio mimicus clustered apart from the other genus members. Vibrio harveyi- and Vibrio splendidus-related species formed compact separated groups. On the other hand, species related to Vibrio tubiashii appeared scattered in the phylogenetic tree. The pairs Vibrio coralliilyticus and Vibrio neptunius, Vibrio nereis and Vibrio xuii and V. tubiashii and Vibrio brasiliensis clustered completely apart from each other. There was a correlation of 0·58 between recA and 16S rDNA pairwise similarities. Strains of the same species have at least 94 % recA sequence similarity. recA gene sequences are much more discriminatory than 16S rDNA. For 16S rDNA similarity values above 98 % there was a wide range of recA similarities, from 83 to 99 %

    <i>Vibrio coralliilyticus</i> sp. nov., a temperature-dependent pathogen of the coral <i>Pocillopora damicornis</i>

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    Vibrio sp. YB1T (=ATCC BAA-450T =LMG 20984T), the aetiological agent of tissue lysis of the coral Pocillopora damicornis, was characterized as a novel Vibrio species on the basis of 16S rDNA sequence, DNA-DNA hybridization data (G+C content is 45·6 mol%), AFLP and GTG5-PCR genomic fingerprinting patterns and phenotypic properties, including the cellular fatty acid profile. The predominant fatty acids were 16 : 0 and 18 : 1?7c. The name Vibrio coralliilyticus sp. nov. is proposed for the novel coral-pathogenic species. In addition to strain YB1T, which was isolated from the Indian Ocean, five additional strains of V. coralliilyticus have been isolated, three from diseased P. damicornis in the Red Sea, one from diseased oyster larvae (Kent, UK) and one from bivalve larvae (Brazil). The six V. coralliilyticus strains showed high genotypic and phenotypic similarities and all were pathogenic to P. damicornis. The closest phylogenetic neighbours to V. coralliilyticus are Vibrio tubiashii, Vibrio nereis and Vibrio shilonii</i

    <i>Echinicola vietnamensis</i> sp. nov., a member of the phylum <i>Bacteroidetes</i> isolated from seawater

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    The taxonomic position of a novel marine, heterotrophic, gliding, halotolerant and light-pink-pigmented bacterium, designated strain KMM 6221T, was examined by using a polyphasic approach. 16S rRNA gene sequence analysis indicated that strain KMM 6221T is affiliated with the genus Echinicola, a member of the phylum Bacteroidetes, with levels of similarity of 94.7–95.0 % to strains of Echinicola pacifica. Growth of strain KMM 6221T was observed with 0–15 % NaCl and at 6–44 °C. The DNA G+C content of strain KMM 6221T was 45.9 mol%. On the basis of molecular distinctiveness supported by phenotypic and chemotaxonomic data, strain KMM 6221T is considered to represent a novel species of the genus Echinicola, for which the name Echinicola vietnamensis sp. nov. is proposed. The type strain is KMM 6221T (=DSM 17526T=LMG 23754T)

    Theoretical and experimental study of AC loss in HTS single pancake coils

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    The electromagnetic properties of a pancake coil in AC regime as a function of the number of turns is studied theoretically and experimentally. Specifically, the AC loss, the coil critical current and the voltage signal are discussed. The coils are made of Bi2Sr2Ca2Cu3O10/Ag (BiSCCO) tape, although the main qualitative results are also applicable to other kinds of superconducting tapes, such as coated conductors. The AC loss and the voltage signal are electrically measured using different pick up coils with the help of a transformer. One of them avoids dealing with the huge coil inductance. Besides, the critical current of the coils is experimentally determined by conventional DC measurements. Furthermore, the critical current, the AC loss and the voltage signal are simulated, showing a good agreement with the experiments. For all simulations, the field dependent critical current density inferred from DC measurements on a short tape sample is taken into account.Comment: 22 pages, 15 figures; contents extended (sections 3.2 and 4); one new figure (figure 5) and two figures replaced (figures 3 and 8); typos corrected; title change

    Knot invariants in lens spaces

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    In this survey we summarize results regarding the Kauffman bracket, HOMFLYPT, Kauffman 2-variable and Dubrovnik skein modules, and the Alexander polynomial of links in lens spaces, which we represent as mixed link diagrams. These invariants generalize the corresponding knot polynomials in the classical case. We compare the invariants by means of the ability to distinguish between some difficult cases of knots with certain symmetries

    <i>Vibrio neptunius</i> sp. nov., <i>Vibrio brasiliensis</i> sp. nov. and <i>Vibrio xuii</i> sp. nov., isolated from the marine aquaculture environment (bivalves, fish, rotifers and shrimps)

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    The fluorescent amplified fragment length polymorphism (FAFLP) groups A5 (21 isolates), A8 (6 isolates) and A23 (3 isolates) distinguished in an earlier paper (Thompson et al., Syst Appl Microbiol 24, 520-538, 2001) were examined in more depth. These three groups were phylogenetically related to Vibrio tubiashii, but DNA-DNA hybridization experiments proved that the three AFLP groups are in fact novel species. Chemotaxonomic and phenotypic analyses further revealed several differences among the 30 isolates and known Vibrio species. It is proposed to accommodate these isolates in three novel species, namely Vibrio neptunius (type strain LMG 20536T; EMBL accession no. AJ316171; G + C content of the type strain 46·0 mol%), Vibrio brasiliensis (type strain LMG 20546T; EMBL accession no. AJ316172; G + C content of the type strain 45·9 mol%) and Vibrio xuii (type strain LMG 21346T; EMBL accession no. AJ316181; G + C content of the type strain 46·6 mol%). These species can be differentiated on the basis of phenotypic features, including fatty acid composition (particularly 14 : 0 iso, 14 : 0 iso 3-OH, 16 : 0 iso, 16 : 0, 17 : 0 and 17 : 1?8c), enzyme activities and utilization and fermentation of various carbon sources
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