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Caldisericum exile gen. nov., sp. nov., an anaerobic, thermophilic, filamentous bacterium of a novel bacterial phylum, Caldiserica phyl. nov., originally called the candidate phylum OP5, and description of Caldisericaceae fam. nov., Caldisericales ord. nov. and Caldisericia classis nov.

Iamia majanohamensis gen. nov., sp. nov., an actinobacterium isolated from sea cucumber Holothuria edulis, and proposal of Iamiaceae fam. nov. Kurahashi & Yokota, 2007b). In this study we used SN medium, which is commonly used for algal cultivation, and a novel bacterial strain (F12 T ), forming a deep branch with Acidimicrobium ferrooxidans in the order Acidimicrobiales, was isolated.Acidimicrobium strains are Gram-positive, rod-shaped bacteria that are found in warm, acidic, sulphur-or mineral sulphide-rich environments. Acidimicrobium ferrooxidans was originally described by Clark & Norris (1996) and was subsequently placed in the subclass Acidimicrobidae (Stackebrandt et al., 1997), which contains only the order Acidimicrobiales, family Acidimicrobiaceae, genus Acidimicrobium and one species, Acidimicrobium ferrooxidans. Interestingly, Rheims et al. (1999) carried out molecular environmental studies and discovered the existence of several novel 16S rRNA gene sequence clusters with probable worldwide distribution in different terrestrial environments, forming several lineages deeply rooted to the order Acidimicrobiales. However, no novel species belonging to these clusters have been reported.The strain used in this study was obtained from the abdominal epidermis of a sea cucumber, Holothuria edulis, which was collected off the coast of Aka Island, Okinawa prefecture, Japan, at a depth of 6 m, as described previously (Kurahashi & Yokota, 2004). The medium used for isolation of strain F12T was SN medium, consisting of Abbreviations: DAP, diaminopimelic acid; ML, maximum likelihood; NJ, neighbour joining; TEM, transmission electron microscopy.The GenBank/EMBL/DDBJ accession number for the 16S rRNA gene sequence of strain F12 T is AB360448.A supplementary figure showing the general morphology of cells of strain F12 T is available with the online version of this paper.

Euzebya tangerina gen. nov., sp. nov., a deeply branching marine actinobacterium isolated from the sea cucumber Holothuria edulis, and proposal of Euzebyaceae fam. nov., Euzebyales ord. nov. and Nitriliruptoridae subclassis nov. A tangerine-coloured, Gram-positive actinobacterial strain, designated F10 T , was isolated from the abdominal epidermis of a sea cucumber, Holothuria edulis, collected in seawater off the coast of Japan. A 16S rRNA gene sequence analysis indicated that strain F10 T was a member of the class Actinobacteria and was most closely related to Nitriliruptor alkaliphilus ANL-iso2 T (87.4 % sequence similarity). Phylogenetic analyses showed that strain F10 T represented a novel, deeprooted, and distinct phylogenetic lineage within the class Actinobacteria and clustered with N. alkaliphilus and uncultured bacteria. The organism had meso-diaminopimelic acid as the diagnostic diamino acid in the cell-wall peptidoglycan, and rhamnose and galactose as the diagnostic cell-wall sugars. Strain F10 T contained C 16 : 1 v7c, C 16 : 0 and C 17 : 1 v8c as the major cellular fatty acids. The predominant isoprenoid quinone was MK-9 (H 4 ). The G+C content of the DNA was 68.3 mol%. Based on data from the current polyphasic study, it is proposed that the new marine isolate be placed in a novel genus and be considered a novel species designated Euzebya tangerina gen. nov., sp. nov. within the new family, order and subclass Euzebyaceae fam. nov., Euzebyales ord. nov. and Nitriliruptoridae subclassis nov. in the class Actinobacteria. The type strain of Euzebya tangerina is F10 T (5NBRC 105439 T 5KCTC 19736 T ).In the course of searching for novel lineages of bacteria from the intestine and epidermis of marine creatures, a novel bacterial strain, F10 T , was isolated, and this strain was shown to form a deep branch in the class Actinobacteria. As the field of marine actinobacterial research is still in its early stages (Bull et al., 2005), the isolation and taxonomic characterization of strain F10 T promises to increase our understanding of marine actinobacteria. Stackebrandt et al. (1997) proposed a hierarchical classification system for the actinobacteria by conducting 16S rRNA gene sequence analyses and by distinguishing between patterns of signature nucleotides. As a result, the phylum Actinobacteria was classified into 5 subclasses within one class Actinobacteria Stackebrandt et al. 1997: Acidimicrobidae Stackebrandt et al. 1997, Rubrobacteridae Stackebrandt et al. 1997, Coriobacteridae Stackebrandt et al. 1997, Actinobacteridae Stackebrandt et al. 1997 and Sphaerobacteridae Stackebrandt et al. 1997. Sphaerobacter thermophilus was originally described by Demharter et al. (1989) and was subsequently placed in the subclass Sphaerobacteridae, which contains only the order Sphaerobacterales, the family Sphaerobacteraceae, the genus Sphaerobacter, and one species, S. thermophilus. More recently, Hugenholtz & Stackebrandt (2004) proposed the reclassification of S. thermophilus from the subclass Sphaerobacteridae...

Actinomycetes were isolated from 109 soil and 93 leaf-litter samples collected at five sites in Vietnam between 2005 and 2008 using the rehydration-centrifugation (RC) method, sodium dodecyl sulfate-yeast extract dilution method, dry-heating method and oil-separation method in conjunction with humic acid-vitamin agar as an isolation medium. A total of 1882 strains were identified as Vietnamese (VN)-actinomycetes including 1080 (57%) streptomycetes (the genus Streptomyces isolates) and 802 (43%) non-streptomycetes. The 16S ribosomal RNA gene sequences of the VN-actinomycetes were analyzed using BLAST searches. The results showed that these isolates belonged to 53 genera distributed among 21 families. Approximately 90% of these strains were members of three families: Streptomycetaceae (1087 strains, 58%); Micromonosporaceae (516 strains, 27%); and Streptosporangiaceae (89 strains, 5%). Motile actinomycetes of the genera Actinoplanes, Kineosporia and Cryptosporangium, which have quite common morphological characteristics, were frequently isolated from leaf-litter samples using the RC method. It is possible that these three genera acquired common properties during a process of convergent evolution. By contrast, strains belonging to the suborder Streptosporangineae were exclusively isolated from soils. A comparison of the sampling sites revealed no significant difference in taxonomic diversity between these sites. Among the non-streptomycetes, 156 strains (19%) were considered as new taxa distributed into 21 genera belonging to 12 families. Interestingly, the isolation of actinomycetes from leaf-litter samples using the RC method proved to be the most efficient way to isolate new actinomycetes in Vietnam, especially the Micromonosporaceae species.