No abstract

Recently, heterotrophic nanoflagellates (HNF) have been reported to actively ingest prokaryotes in high salinity waters. We report the isolation and culture of an HNF from a Korean saltern pond of 300 per thousand salinity. The organism is biflagellated with an acronematic anterior flagellum and never glides on surfaces. The mitochondria have tubular cristae. Neither transitional helix nor spiral fiber were observed in the transition zones of the flagella. The cell has a cytostome supported by an arc of eight microtubules, suggesting that our isolate is a bicosoecid. Our isolate had neither mastigonemes, lorica, body scales, nor cytopharynx and thus could not be placed in any of the presently described bicosoecid genera. Phylogenetic analysis of 18S rRNA gene sequences from stramenopiles confirmed the bicosoecid affinities of our isolate, but did not place it within any established genus or family. Its closest relatives include Caecitellus and Cafeteria. The optimal range of growth temperature was 30-35 degrees C. The isolated HNF grew optimally at 150 per thousand salinity and tolerated up to 363 per thousand salinity, but it failed to grow below 75 per thousand salinity, indicating that it could be a borderline extreme halophile. On the basis of its morphological features and position in 18S rRNA trees we propose a novel genus for our isolate; Halocafeteria, n. gen. The species name Halocafeteria seosinensis sp. nov. is proposed.

A Gram-staining-negative, rod-shaped and non-motile bacterium, designated CL-SS4T , was isolated from crude-oil-contaminated seawater from the west coast of Korea and was investigated by means of a polyphasic taxonomic approach. Strain CL-SS4 T grew optimally at 25-30 6C, at pH 6.8-7.7 and in the presence of 2-3 % sea salts. The major fatty acids were iso-C 17 : 0 3-OH, iso-C 15 : 0 and iso-C 15 : 1 G. The major isoprenoid quinone was MK-6. The DNA G+C content was 50.7 mol%. Analysis of the 16S rRNA gene sequence of strain CL-SS4 T revealed that it was a member of the genus Muricauda, sharing 95.7-96.9 % sequence similarity with the type strains of Muricauda species and being most closely related to Muricauda aquimarina SW-63 T . Phylogenetic analyses based on 16S rRNA gene sequences confirmed that strain CL-SS4

Lutibacter litoralis gen. nov., sp. nov., a marine bacterium of the family Flavobacteriaceae isolated from tidal flat sediment

Strains in the Roseobacter clade, classified within the family Rhodobacteraceae, have been isolated mainly from various marine environments (seawater, sediment, hypersaline microbial mats and coastal biofilms) and from marine algae, invertebrates and vertebrates, and the Roseobacter clade is known to be one of the most abundant groups in marine environments (Giovannoni & Rappé, 2000;Selje et al., 2004;Buchan et al., 2005). The strains show diverse physiological and morphological features (e.g. phototrophy, aerobic sulfite oxidation, organic sulfur compound degradation, methylotrophy, gas vacuoles, poly-b-hydroxybutyrate granules, rosette formation) (Arahal et al., 2005;Buchan et al., 2005). Furthermore, phylogenetic analyses of marine Roseobacter sequences have shown that for two-thirds (68 %) of the Roseobacter diversity identified so far, it is not yet possible to access relevant physiological information through studies of cultured organisms (Buchan et al., 2005). In early stages of biofilm establishment, clones affiliated with the Roseobacter clade accounted for 85 % of the total sequenced clones, suggesting that organisms belonging to the Roseobacter clade are ubiquitous and rapid colonizers of surfaces in coastal environments (Dang & Lovell, 2000).In this study, a strain affiliated with the Rhodobacteraceae, CL-TA03 T , was isolated in October 2002 from a biofilm formed on an acrylic slide submerged for 1 month in surface water on a coastal fish farm in Tongyeong, Korea. The scraped biofilm was suspended in seawater that had been passed through a 0?2 mm filter and autoclaved. The suspension was spread on a marine agar 2216 (MA; Difco) plate and incubated at 25 u C for 1 week. Strain CL-TA03T was isolated and subsequently purified four times on MA at 30 uC. The strain was maintained both on MA at 4 uC and in marine broth 2216 (MB; Difco), supplemented with 30 % (v/v) glycerol, at 280 uC.The 16S rRNA gene was amplified from a single colony by PCR with Taq DNA polymerase (Bioneer) using primers 27F and 1492R (Lane, 1991). The PCR product was purified using the AccuPrep PCR Purification kit (Bioneer) and cloned using the pCR2.1 TOPO TA Cloning kit (Invitrogen). Sequencing of the 16S rRNA gene was performed with an Applied Biosystems automatic sequencer (ABI 3730xl) at Macrogen Corp., Seoul, Korea. An almost complete 16S rRNA gene sequence of strain CL-TA03 T (1382 bp) was obtained. The sequence of strain CL-TA03T was compared with 16S rRNA gene sequences available in GenBank using The GenBank/EMBL/DDBJ accession number for the 16S rRNA gene sequence of strain CL-TA03T is AY962292. G 2006 IUMS Printed in Great Britain