RESUMO
A novel coccoid, anaerobic, Fe2+-oxidizing archaeum was isolated from a shallow submarine hydrothermal system at Vulcano, Italy. In addition to ferrous iron, H2 and sulfide served as electron donors. NO3- was used as electron acceptor. In the presence of H2, also S2O32- could serve as electron acceptor. The isolate was a neutrophilic hyperthermophile that grew between 65 degrees C and 95 degrees C. It represents a novel genus among the Archaeoglobales that we name Ferroglobus. The type species is Ferroglobus placidus (DSM 10642).
Assuntos
Archaea/classificação , Archaea/isolamento & purificação , Archaea/genética , Archaea/ultraestrutura , Técnicas Bacteriológicas , Composição de Bases , DNA Bacteriano/análise , Concentração de Íons de Hidrogênio , Ferro/metabolismo , Lipídeos/análise , Microscopia Eletrônica , Microscopia Eletrônica de Varredura , Filogenia , RNA Ribossômico 16S/análise , Cloreto de Sódio/metabolismoRESUMO
A novel, extremely thermophilic bacterium has been isolated from a neutral volcanic hot spring. The gram-negative, rod-shaped cells were motile and exhibited a complex cell wall composed of murein and a surface protein layer covered by a surface coat. The core lipids consisted of non-phytanyl mono- and diethers and of fatty acid esters. Growth occurred between 57 and 77 degrees C (opt.: 70 degrees C), pH 5.0 and 8.0 (opt.: 7.5) and 0 to 1.5% NaCl (opt.: 0.1% NaCl). The new isolate was a strict anaerobe, growing autotrophically by oxidation of hydrogen or formate, reducing nitrate to ammonium. Instead of nitrate, sulfate or sulfur were used as electron acceptors and H2S was formed as final product. Pyruvate was fermented to acetate, CO2, and hydrogen. The GC-content of the DNA was 54 mol%. On the basis of its 16S rRNA sequence, the new isolate represents a new genus, belonging to the "low G+C" subgroup of the gram-positive bacteria. Strain KC4 (DSM 10501) is described as the type strain of a new genus and species, which we name Ammonifex degensii.
Assuntos
Bactérias Gram-Positivas/classificação , Temperatura Alta , Nitratos/metabolismo , Compostos de Amônio Quaternário/metabolismo , Bactérias Redutoras de Enxofre/metabolismo , Água Doce , Bactérias Gram-Positivas/química , Bactérias Gram-Positivas/metabolismo , Bactérias Gram-Positivas/ultraestrutura , Indonésia , Lipídeos/análise , Microscopia Eletrônica , Oxirredução , Filogenia , Bactérias Redutoras de Enxofre/química , Bactérias Redutoras de Enxofre/classificação , Bactérias Redutoras de Enxofre/ultraestrutura , Microbiologia da ÁguaRESUMO
A variety of hyperthermophilic bacteria and archaea have been isolated from high-temperature environments by plating and serial dilutions. However, these techniques allow only the small percentage of organisms able to form colonies, or those that are predominant within environmental samples, to be obtained in pure culture. Recently, in situ 16S ribosomal RNA analyses of samples from the Obsidian hot pool at Yellowstone National Park, Wyoming, revealed a variety of archaeal sequences, which were all different from those of previously isolated species. This suggests substantial diversity of archaea with so far unknown morphological, physiological and biochemical features, which may play an important part within high-temperature ecosystems. Here we describe a procedure to obtain pure cultures of unknown organisms harbouring specific 16S rRNA sequences identified previously within the environment. It combines visual recognition of single cells by phylogenetic staining and cloning by 'optical tweezers'. Our result validates polymerase chain reaction data on the existence of large archael communities.
