A novel species of thermoacidophilic archaeon, Sulfolobus yangmingensis sp. nov.Ren-Long Jan,' Jeffrey Wu,' Shu-Miaw Chaw,3 Chien-Wei Tsai' and Suh-Der Tsen'Author for correspondence: Suh-Der Tsen. Tel: +886 2 28267108. Fax: $886 2 28212880. e-mail : nymut sen @, yrn.edu. twInstitute of Microbiology and immunology, National Yang-Ming University, ShihPail, Taipei American School2 and Institute of Botany, Academia Sinica3, Taipei, Taiwan, ROC A novel microbe was isolated from a geothermal vent in Yang-Ming National Park in northern Taiwan. This spherical microbe with mean cell diameter of 1.1 20-2 pm is a facultatively chemolithoautotrophic archaeon that grows on elemental sulfur and reduced sulfur compounds. The optimal pH and temperature for growth are 4-0 (pH range 2.0-6.0) and 80 "C (temperature range 65-95 "C). Its membranes contain the lipids calditoglycerocaldarchaeol and caldarchaeol, which are common to other members of the Sulfolobaceae. Like Sulfolobus acidocaldarius, Sulfolobus shibatae and Sulfolobus solfataricus, the new isolate utilizes sugars and amino acids effectively as sole carbon sources. The G+C content of the genomic DNA was 42 mol0/o. DNA of the isolate hybridized weakly to the DNA of other Sulfolobus species. Phylogenetic analysis of the 165 rRNA indicated that the new isolate represents a deep branch within the genus Sulfolobus. On the basis of these properties, the new isolate appears to represent a new species of Sulfolobus, for which the name Sulfolobus yangmingensis sp. nov. is proposed. The type strain is strain YMIT.1 Keywords: thermoacidophile, archaeon, Sulfolobus
INTRODUCTIONMembers of the genus Sulfolobus, the first reported genus of the family Sulfolobaceae (Brock et al., 1972;Segerer et al., 1986), are characterized by aerobic growth at high temperatures and low pH in the presence of elemental sulfur. Members of the genus are usually found in habitats such as acidic hot springs and mud holes that contain elemental sulfur. Among the described species of Sulfolobus, Sulfolobus acidocaldarius, originally discovered in Yellowstone National Park, USA, and Sulfolobus solfataricus, originally discovered in Pisciarelli, Italy, have been used widely in research. Both species are distributed worldwide. Sulfolobus hakonensis was isolated in Hakone, Japan (Takayanagi et al., 1996).Taiwan has many active geothermal vents. A new microbial strain was isolated from an acidic, muddy, hot spring in Longfong valley at the southern YangAbbreviations: MP, maximum-parsimony; NJ, neighbour-joining.The GenBank accession number for the 16s rDNA sequence of strain YMIT is AB010957.Ming National Park in northern Taiwan. The temperature of this hot spring can reach 105 "C and the pH is as low as 2. In this report, we have characterized this novel strain in terms of morphology, nutritional requirements, DNA homology with similar species and phylogenetic analysis of its 16s rRNA sequence.
METHODSMicrobial strains. S. acidocaldarius DSM 639', S. hakonensis DSM 7519', Sulfolobus shibatae DSM 5389' and S. sol...