New Hyperthermophilic Organotrophic Archaea from Kamchatka Thermal Areas
Margarita L. MIROSHNICHENKO, Maria I.PROKOFJEVA, Vitlay A. SVETLICHNY, and Elizaveta A. BONCH-OSMOLOVSKAYA
Department of Microbial Communities, Institute of Microbiology, Russian Academy of Sciences, prospect 60 Letiya Oktyabrya 7/2, 117811 Moscow, Russia
From caldera Uzon and Moutnovski volcano hot springs two anaerobic organotrophic archaea were isolated and characterized. Isolate 1312 obtained from a neutral hot spring of Uzon caldera has cells of regular coccoid shape, 1-2 μm in diameter, with one long fiagellum. Growth is optimal at 82℃ and pH 6.0. Various carbohydrates and polysaccharides are fermented under obligately anaerobic conditions with acetate, molecular hydrogen and CO2 as growth products. Elemental sulfur is neither required nor stimulating; molecular hydrogen does not suppress growth. G+C content of the DNA is 42.5 mol%. Isolate 1904 was obtained from an acidic hot spring of Moutnovski volcano. Its cells are irregular cocci having no flagella and diameter not exceeding 1 μm. Characteristic features of the new isolate are: (1) an unusual cell envelope structure and (2) the specific mode of division by fragmentation to several lobes at once. This isolate grows optimally at 78-80℃ and pH 3.5-3.8, is an obligate anaerobe growing on starch, or yeast and beef extracts. Elemental sulfur supply stimulates the growth significantly. The G+C content of the DNA is 53.8 mol%.
