Phyllobacterium catacumbae sp. nov., a member of the order 'Rhizobiales' isolated from Roman catacombs

Two strains were isolated from tuff, a volcanic rock that forms the walls of the Roman Catacombs of Saint Callixtus in Rome, Italy. A polyphasic approach using nutritional and physiological tests, reactions to antibiotics, fatty acid profiles, DNA base ratios, DNA-DNA reassociation and 16S rRNA gene sequence comparisons showed that the two isolates belong to a novel species within the genus Phyllobacterium. The species Phyllobacterium catacumbae sp. nov. is proposed. The type strain is CSC19T (=CECT 5680T=LMG 22520T).V. J. and L. L. received fellowships from the Spanish Ministry of Education and Science (MEC), I3P programme and J. M. G. is supported by an MEC contract from the ‘Ramón y Cajal’ program. This study was supported by EC project EVK4-CT2000-00028 and MEC project BTE2002-04492-C02-01.Peer Reviewe

Salicola marasensis gen. nov., sp. nov., an extremely halophilic bacterium isolated from the Maras solar salterns in Peru

Six strains of extremely halophilic bacteria were isolated from several crystallizer ponds of the Maras solar salterns in the Peruvian Andes. On the basis of 16S rRNA gene sequence similarity, G+C contents and DNA-DNA hybridization results, the six isolates constituted a genomically homogeneous group affiliated with the Gammaproteobacteria. The closest relatives were members of the halophilic genera Halovibrio and Halospina, which showed 16S rRNA gene sequence similarities below 97% and whole-genome hybridization levels below 33% for the type strain, 7Sm5T. From the genomic and phenotypic properties of the six novel isolates and phylogenetic reconstruction based on 16S rRNA gene sequence analysis, they can be considered to represent a novel genus within the Gammaproteobacteria. On the basis of the taxonomic study, a novel genus, Salicola gen. nov., is proposed containing the single species Salicola marasensis sp. nov., which is the type species. The type strain of Salicola marasensis is 7Sm5T ( = CECT 7107T = CIP 108835T). © 2006 IUMS.The authors’ research is funded by the following projects: BIO2000-005-P4-04 and BOS-2003-05198-C02-01 and BOS-2003-05198-C02-02 of the Spanish Ministry of Science and Education, grant GRUPOS03/137 from the Generalitat Valenciana and the network of excellence Marine Genomics Europe (GOCE-CT-505403) of the European UnionPeer Reviewe

Identification of a bacterial strain isolated from the liver of a laboratory mouse as Microbacterium paraoxydans and emended description of the species Microbacterium paraoxydans Laffineur et al 2003

A rod-shaped, Gram-positive bacterial strain, designated C57-33, was isolated from the liver of the laboratory mouse strain C57Bl/6J and characterised by a polyphasic approach. 16S rRNA gene sequence similarity placed strain C57-33 in the genus Microbacterium with Microbacterium paraoxydans CF36T as the next relative (99.9% sequence similarity). Major fatty acids ai-C15:0, i-C16:0 and ai-C17:0 and peptidoglycan type B2β with ornithine as the diagnostic cell-wall diamino acid and glycolyl residues were in agreement with the description of Microbacterium paraoxydans. The quinone system of C57-33 (major menaquinones MK-12 and MK-11) and polar lipid profile (major polar lipids diphosphatidyl glycerol, phosphatidyl glycerol and two unknown glycolipids) were in accordance with those of Microbacterium paraoxydans strains CF36T, CF7 and CF40 which were analysed in this study as well. The results of biochemical/ physiological characterisation, DNA-DNA hybridization, MALDI-TOF mass spectrometry of cell extracts and comparison of protein patterns after SDS-PAGE demonstrated that our isolate C57-33 (= DSM 15461) is a strain of the species Microbacterium paraoxydans. Based on new characteristics such as quinone system, polar lipid profile and physiological traits analysed for strain C57-33, the type strain of Microbacterium paraoxydans and some additional strains an emended description of the species Microbacterium paraoxydans is provided. © 2008 Association of Microbiologists of India.Peer Reviewe

Identification of a bacterial strain isolated from the liver of a laboratory mouse as Microbacterium paraoxydans and emended description of the species Microbacterium paraoxydans Laffineur et al 2003

A rod-shaped, Gram-positive bacterial strain, designated C57-33, was isolated from the liver of the laboratory mouse strain C57Bl/6J and characterised by a polyphasic approach. 16S rRNA gene sequence similarity placed strain C57-33 in the genus Microbacterium with Microbacterium paraoxydans CF36T as the next relative (99.9% sequence similarity). Major fatty acids ai-C15:0, i-C16:0 and ai-C17:0 and peptidoglycan type B2β with ornithine as the diagnostic cell-wall diamino acid and glycolyl residues were in agreement with the description of Microbacterium paraoxydans. The quinone system of C57-33 (major menaquinones MK-12 and MK-11) and polar lipid profile (major polar lipids diphosphatidyl glycerol, phosphatidyl glycerol and two unknown glycolipids) were in accordance with those of Microbacterium paraoxydans strains CF36T, CF7 and CF40 which were analysed in this study as well. The results of biochemical/ physiological characterisation, DNA-DNA hybridization, MALDI-TOF mass spectrometry of cell extracts and comparison of protein patterns after SDS-PAGE demonstrated that our isolate C57-33 (= DSM 15461) is a strain of the species Microbacterium paraoxydans. Based on new characteristics such as quinone system, polar lipid profile and physiological traits analysed for strain C57-33, the type strain of Microbacterium paraoxydans and some additional strains an emended description of the species Microbacterium paraoxydans is provided. © 2008 Association of Microbiologists of India.Peer Reviewe

A detailed phenotypic and genotypic description of Pseudomonas strain OX1

Strain OX1 exhibits important physiological, ecological, and biotechnological properties in the degradation of chemical pollutants. It was previously classified as a member of Pseudomonas stutzeri based on its phenotypic characteristics. The present taxonomic study describes phenotypic and genomic properties of strain OX1 and illustrates the value both of multigenic sequence analysis and siderotyping methods to justify its species circumscription within the genus Pseudomonas. We have concluded that strain OX1 is a member of the Pseudomonas corrugata group, distantly related to P. stutzeri, and should be considered representative of a new species. However, phenotypic differentiation between species in this group remains difficult, and species proposals based on only a single strain must be cautious. We, therefore, prefer not to propose a new species until more strains with the same genomic and phenotypic properties as strain OX1 have been isolated. © 2005 Elsevier GmbH. All rights reserved.Peer Reviewe

Phylogenetic position of Salinibacter ruber based on concatenated protein alignments

A total of 22 genes from the genome of Salinibacter ruber strain M31 were selected in order to study the phylogenetic position of this species based on protein alignments. The selection of the genes was based on their essential function for the organism, dispersion within the genome, and sufficient informative length of the final alignment. For each gene, an individual phylogenetic analysis was performed and compared with the resulting tree based on the concatenation of the 22 genes, which rendered a single alignment of 10,757 homologous positions. In addition to the manually chosen genes, an automatically selected data set of 74 orthologous genes was used to reconstruct a tree based on 17,149 homologous positions. Although single genes supported different topologies, the tree topology of both concatenated data sets was shown to be identical to that previously observed based on small subunit (SSU) rRNA gene analysis, in which S. ruber was placed together with Bacteroidetes. In both concatenated data sets the bootstrap was very high, but an analysis with a gradually lower number of genes indicated that the bootstrap was greatly reduced with less than 12 genes. The results indicate that tree reconstructions based on concatenating large numbers of protein coding genes seem to produce tree topologies with similar resolution to that of the single 16S rRNA gene trees. For classification purposes, 16S rRNA gene analysis may remain as the most pragmatic approach to infer genealogic relationships. © 2006 Elsevier GmbH. All rights reserved.The authors’ research is founded by the following projects: BOS-2003-05198-C02-01 and -02 of the Spanish Ministry of Science and Education, a research grant in bioinformatics from the Fundación BBVA (Spain), the grant GRUPOS03/137 from the Generalitat Valenciana, and the network of excellence Marine Genomics Europe GOCE-CT-505403 of the European UnionPeer Reviewe

Intraspecific comparative analysis of the species Salinibacter ruber

Salinibacter ruber is the first extremely halophilic member of the Bacteria domain of proven environmental relevance in hypersaline brines at or approaching NaCl saturation, that has been brought to pure culture. A collection of 17 strains isolated from five different geographical locations (Mallorca, Alicante, Ebro Delta, Canary Islands, and Peruvian Andes) were studied following the currently accepted taxonomic approach. Additionally, random amplification of genomic DNA led to the phenetic analysis of the intraspecific diversity. Altogether the taxonomic study indicated that S. ruber remained highly homogeneous beyond any geographical barrier. However, genomic fingerprints indicated that populations from different isolation sites could still be discriminated. © Springer-Verlag 2005.This work was supported by the research projects BOS-2000-1123-C02-01, --02, BOS-2003-05198-C02-01, --02 from the Spanish Ministry of Science and Technology (to JA and RRM); and by the Acción Especial of the Govern de les Illes Balears (to RRM), and GRUPOS03/137 of the Generalitat Valenciana (to JA). The work has as well been done in the frame of the European Network of Excellence Marine Genomics Europe GOCE-CT-2004-505403 (to RRM and RA)Peer Reviewe

Metabolic evidence for biogeographic isolation of the extremophilic bacterium Salinibacter ruber

The biogeography of prokaryotes and the effect of geographical barriers as evolutionary constraints are currently subjected to great debate. Some clear-cut evidence for geographic isolation has been obtained by genetic methods but, in many cases, the markers used are too coarse to reveal subtle biogeographical trends. Contrary to eukaryotic microorganisms, phenotypic evidence for allopatric segregation in prokaryotes has never been found. Here we present, for the first time, a metabolomic approach based on ultrahigh resolution mass spectrometry to reveal phenotypic biogeographical discrimination. We demonstrate that strains of the cosmopolitan extremophilic bacterium Salinibacter ruber, isolated from different sites in the world, can be distinguished by means of characteristic metabolites, and that these differences can be correlated to their geographical isolation site distances. The approach allows distinct degrees of discrimination for isolates at different geographical scales. In all cases, the discriminative metabolite patterns were quantitative rather than qualitative, which may be an indication of geographically distinct transcriptional or posttranscriptional regulations. © 2008 International Society for Microbial Ecology All rights reserved.Funding for this study was provided by the Ministerio de Educación y Ciencia through the research projects CLG2006-12714-C02-01 and -02Peer Reviewe

Occurrence of rhizobia in the gut of the higher termite Nasutitermes nigriceps

Wood-eating termites feed on a diet highly deficient in nitrogen. They must complement their diet with the aid of nitrogen-fixing bacteria. Nitrogen fixation in the gut has been demonstrated, but information about nitrogen-fixing bacteria in pure culture is scarce. From the higher termite Nasutitermes nigriceps the symbiotic bacterial strain M3A was isolated, which thrives in the hindgut contents. The Gram-negative strain exhibited similarities to the species of the genus Ensifer (including Sinorhizobium) on the basis of morphological and physiological/biochemical features. The 16S rRNA gene analysis showed the highest sequence similarity of the isolate M3A to Ensifer adhaerens (>99%; ATCC 33499). The DNA-DNA hybridization revealed a similarity of 66% with E. adhaerens (NCIMB12342T). In contrast to the type strain the isolate M3A possesses the capacity to nodulate plant roots. This is the first report on the detailed identification of a rhizobia-related strain from the intestinal tract of animals. Strain M3A has been deposited with two culture collections (DSM10169; ATCC BAA-396). © 2006 Elsevier GmbH. All rights reserved.This work was supported by the Deutsche Forschungsgemeinschaft (Ko 785). Research of R. R. was supported by the Spanish Ministry of Science and Technology with the grant BOS-2003-05198-C02-01Peer Reviewe