RESUMO
A Gram-stain-negative, rod-shaped, non-flagellated, pink, cold-tolerant bacterial strain, NH7-4T, was isolated from the Riganqiao peatlands on the Tibetan Plateau. The 16S rRNA gene sequence of the novel isolate shared a pairwise similarity ranging from 96.84 to 93.02â% with type strains of species of the genus Mucilaginibacter. Growth of strain NH7-4T occurred between 0 and 30 °C and at pH 5.0-9.0, with an optimum growth temperature at 20 °C and an optimum pH for growth of approximately 7.0. The major isoprenoid quinone was MK-7. The major cellular fatty acids were summed feature 3 (C16â:â1ω7c and/or iso-C15â:â0 2-OH), iso-C15â:â0, iso-C17â:â0 3-OH, C16â:â0, iso-C15â:â0 3-OH and C16â:â1ω5c. The major polar lipid of strain NH7-4T was phosphatidylethanolamine. Strain NH7-4T did not assimilate any substrates in API 20NE strips without low concentrations of yeast extract being present and had a lower optimal growth temperature, which distinguished it from other type strains of species of the genus Mucilaginibacter. The DNA G+C content of strain NH7-4T was 48.6 mol%. Based on phylogenetic, phenotypic and chemotaxonomic data, strain NH7-4T (=JCM 30607T=CGMCC1.14937T) represents a novel species of the genus Mucilaginibacter for which the name Mucilaginibacter psychrotolerans sp. nov. is proposed.
Assuntos
Bacteroidetes/classificação , Filogenia , Microbiologia do Solo , Áreas Alagadas , Técnicas de Tipagem Bacteriana , Bacteroidetes/genética , Bacteroidetes/isolamento & purificação , Composição de Bases , DNA Bacteriano/genética , Ácidos Graxos/química , Fosfatidiletanolaminas/química , Pigmentação , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Tibet , Vitamina K 2/análogos & derivados , Vitamina K 2/químicaRESUMO
Bacterial diversity and cell abundance in the snow of the four glaciers (Guoqu, Zadang, East Rongbuk and Palong No. 4) located in different climatic zones of the Tibetan Plateau were investigated through culture-independent molecular analysis of 16S rRNA gene clone library and flow cytometry approaches. Cell abundance ranged from 0.68 x 10(3) to 720 x 10(3) cells mL(-1), with higher values in the northern glaciers than in the southern ones. Bacterial diversity was unexpectedly high in the snow habitats of the world's highest plateau, with 15 common genera distributed widely among the glaciers. The bacterial diversity in the snow at different glaciers was related to the surrounding environments. The Guoqu Glacier, to the north near the desert zone and with the lowest temperature, preserved more bacteria closely related to a cold environment and soil than the other glaciers. However, in the Palong No. 4 Glacier located in the south warm region around vegetation, most bacteria were phylogenetically related to plant-associated bacteria.
