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Morphological, Small Subunit rRNA, and Physiological Characterization of Trimyema minutum (Kahl, 1931), an Anaerobic Ciliate from Submarine Hydrothermal Vents Growing from 28°C to 52°C
Author(s) -
BAUMGARTNER MANUELA,
STETTER KARL O.,
FOISSNER WLHELM
Publication year - 2002
Publication title -
journal of eukaryotic microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.067
H-Index - 77
eISSN - 1550-7408
pISSN - 1066-5234
DOI - 10.1111/j.1550-7408.2002.tb00527.x
Subject(s) - biology , ciliate , thermophile , hydrothermal vent , ribosomal rna , botany , population , taxonomy (biology) , 16s ribosomal rna , zoology , ecology , hydrothermal circulation , bacteria , genetics , gene , paleontology , demography , sociology
ABSTRACT. A thermophilic strain of Trimyema minutum was isolated from the hydrothermally heated sea floor at Vulcano Island (Italy) and cultivated monoxenically on Marinobaaer sp. and Methanococcus thermolithotrophicus. It can be propagated strictly an aerobically and is sensitive to oxygen: if exposed to air at 48°C all cells die within 60 min. It grows from 0.45–7.2% (w/v) salt and at pH 6.0–8.0. The isolate is the most extreme thermophilic ciliate which ever has been cultivated, exhibiting an optimal growth temperature of 48°C (doubling time 6 h). Growth occurs between 28°C and 52°C. Trimyema minutum is redescribed using live observation and silver impregnation. Its morphology and the small subunit ribosomal RNA sequence is distinctly different from that of T. compressum , but morphology is highly similar to that of T. shoalsia Nerad et al. 1995, which is thus probably a junior synonym of T. minutum . To stabilize the bewildering species taxonomy in Trimyema. we suggest to recognize our population as a neotype of T. minutum.