RESUMEN
Stainless steel electrodes were cathodically polarized at -200 mV versus an Ag/AgCl reference electrode in natural seawater in order to produce current. The current increased and stabilized at 0.5 A/m(2) in less than 10 days. The cultivable fraction of the microbial biofilm population formed on the surface of the current harvesting cathodes was examined by culture dependent techniques. Three hundred fifty six isolates were obtained. They were primarily characterized by whole cell fatty acid methyl ester analysis followed by 16S rRNA gene sequencing. The results showed that the isolates represented different phylogenetic groups including members of the Alpha- and Gammaproteobacteria, the phylum Firmicutes, the family Flavobacteriacae and the phylum Actinobacteria. Denaturing gradient gel electrophoresis demonstrated that the microbial population of the biofilm formed on the cathode and of the surrounding seawater comprised the same dominant members. This study demonstrated that the cultivable microbial fraction of a marine electroactive biofilm is phylogenetically highly diverse.
Asunto(s)
Bacterias Aerobias/genética , Bacterias Aerobias/aislamiento & purificación , Biopelículas , Electrodos/microbiología , Microbiología del Agua , Bacterias Aerobias/clasificación , Variación Genética , Océanos y MaresRESUMEN
Three isolates (LMG 24369(T), LMG 24370 and R-26156) obtained from a marine electroactive biofilm that was grown on a cathodically polarized electrode were investigated by using a polyphasic taxonomic approach. Whole-cell fatty acid methyl ester and 16S rRNA gene sequence analyses indicated that the isolates were members of the genus Phaeobacter, class Alphaproteobacteria. Genotypic and phenotypic analyses demonstrated that the three isolates represent a novel species of the genus Phaeobacter, for which the name Phaeobacter caeruleus sp. nov. is proposed. The type strain is LMG 24369(T) (=CCUG 55859(T)). The DNA G+C content of strain LMG 24369(T) is 63.6 mol%.
Asunto(s)
Biopelículas/crecimiento & desarrollo , Electrodos/microbiología , Rhodobacteraceae/clasificación , Rhodobacteraceae/crecimiento & desarrollo , Agua de Mar , Técnicas de Tipificación Bacteriana , Composición de Base , ADN Bacteriano/análisis , ADN Bacteriano/aislamiento & purificación , ADN Ribosómico/análisis , Ácidos Grasos/análisis , Genotipo , Datos de Secuencia Molecular , Fenotipo , Filogenia , ARN Ribosómico 16S/genética , Rhodobacteraceae/genética , Rhodobacteraceae/aislamiento & purificación , Análisis de Secuencia de ADN , Especificidad de la EspecieRESUMEN
Five isolates obtained from a marine electroactive biofilm grown on a stainless steel cathode were investigated by using a polyphasic taxonomic approach. Analyses of whole-cell fatty acid methyl esters and 16S rRNA gene sequences showed that the isolates belonged to the Roseobacter lineage of the class Alphaproteobacteria. Both phenotypic and genotypic analyses demonstrated that the five new isolates constituted a single species that did not represent a recognized member of the Roseobacter lineage. Therefore the five isolates represent a novel genus and species, for which the name Nautella italica gen. nov., sp. nov. is proposed. The type strain is LMG 24365(T) (=CCUG 55857(T)). The DNA G+C content of the type strain is 61 mol%.
Asunto(s)
Biopelículas , Rhodobacteraceae/clasificación , Rhodobacteraceae/aislamiento & purificación , Microbiología del Agua , Técnicas de Tipificación Bacteriana , Composición de Base , Análisis por Conglomerados , Dermatoglifia del ADN/métodos , ADN Bacteriano/química , ADN Bacteriano/genética , ADN Ribosómico/química , ADN Ribosómico/genética , Ácidos Grasos/análisis , Datos de Secuencia Molecular , Filogenia , ARN Ribosómico 16S/genética , Rhodobacteraceae/genética , Rhodobacteraceae/fisiología , Análisis de Secuencia de ADN , Homología de Secuencia de Ácido NucleicoRESUMEN
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RESUMEN
Seventy isolates were obtained from a marine electroactive biofilm that was generated on a cathodically polarized stainless steel electrode (Genoa, Italy). The genetic diversity was investigated by means of BOX-PCR fingerprinting and two clusters of isolates with similar BOX-PCR profiles were delineated. Whole-cell fatty acid methyl ester analysis and 16S rRNA gene sequence analysis showed that the isolates belonged to the Roseobacter lineage of the class Alphaproteobacteria. DNA-DNA hybridization experiments and a biochemical analysis demonstrated that four isolates belonged to the species Ruegeria mobilis. However, 66 isolates from the second BOX-PCR cluster constituted a novel species within the genus Ruegeria, for which the name Ruegeria scottomollicae sp. nov. is proposed. The DNA G+C content was 61.0+/-0.4 %. The type strain is LMG 24367(T) (=CCUG 55858(T)).
Asunto(s)
Alphaproteobacteria/clasificación , Alphaproteobacteria/fisiología , Biopelículas , Electricidad , Electrodos/microbiología , Alphaproteobacteria/química , Alphaproteobacteria/genética , Alphaproteobacteria/ultraestructura , Ácidos Grasos/análisis , Biología Marina , Microscopía Electrónica de Transmisión , Datos de Secuencia Molecular , Fenotipo , Filogenia , ARN Ribosómico 16S/genética , Especificidad de la EspecieRESUMEN
Strain LMG 24366(T) was isolated from a marine electroactive biofilm grown on a stainless steel cathode (Genova, Italy) and was investigated by using a polyphasic taxonomic approach. This study demonstrated that strain LMG 24366(T) represents a novel species within the genus Leisingera, which shared 98.9 % 16S rRNA gene similarity with its nearest phylogenetic neighbour, Leisingera methylohalidivorans. Strain LMG 24366(T) grew on betaine (1 mM) as a sole carbon source, whereas no growth was observed on L-methionine (10 mM). The phenotypic and genotypic analyses showed that strain LMG 24366(T) could be differentiated from established Leisingera species and that it represented a novel species, for which the name Leisingera aquimarina sp. nov. is proposed. The type strain is LMG 24366(T) (=CCUG 55860(T)) and has a DNA G+C content of 61.4 mol%.
Asunto(s)
Biopelículas , Electrodos/microbiología , Rhodobacteraceae/clasificación , Rhodobacteraceae/fisiología , Dermatoglifia del ADN , Electricidad , Biología Marina , Microscopía Electrónica de Transmisión , Datos de Secuencia Molecular , Fenotipo , Filogenia , ARN Ribosómico 16S/genética , Rhodobacteraceae/genética , Rhodobacteraceae/ultraestructura , Especificidad de la EspecieRESUMEN
Thirty-five isolates obtained from a marine electroactive biofilm grown on a stainless steel cathode (Genoa, Italy) were investigated by a polyphasic taxonomic approach. Whole-cell fatty acid methyl ester analysis indicated that the isolates belonged to the class Gammaproteobacteria and were closely related or belonging to the genus Alteromonas. Genomic fingerprinting using the BOX-PCR primer delineated five clusters of isolates with similar BOX-PCR fingerprints. This study demonstrated that isolates from four of the BOX-PCR clusters belonged to Alteromonas macleodii and that the 14 isolates representing BOX-PCR cluster 1 constituted a novel species, which shared 98.4 % 16S rRNA gene sequence similarity with its nearest phylogenetic neighbour, Alteromonas hispanica. Both phenotypic and genotypic analyses enabled this novel species, for which the name Alteromonas genovensis sp. nov. is proposed, to be differentiated from established species of the genus Alteromonas. The DNA G+C content of Alteromonas genovensis sp. nov. is 44.5 mol% and the type strain is LMG 24078(T) (=CCUG 55340(T)).