一个产生L-乳酸脱氢酶的嗜热菌的新种——非解朊栖热菌

THERMUS NONPROTEOLYTICUS SP.NOV.,A NEW SPECIES OF THERMOPHILIC NONSPOREFORMER PRODUCING LDH

从广东省阳江、电白和韶关等地55—95℃的温泉中采集水样,经分离得到21株 G^-、不产生芽孢的高温菌。它们都能产生 L-乳酸脱氢酶。根据表观特征,DNA 的同源性和 G+Cmol%等特征可归入栖热菌属(Thermus)。但对葡萄糖不产酸和不液化明胶等表型特征不同于已发表的种。又根据该群内的 DNA/DNA 杂交结果,有高的同源性(大多在80%以上),而与已发表的种仅有40.5—70.7%的同源性。结果表明可成立一独立的类群,建议为栖热菌属的一个新种,因具不液化明胶的特性,命名为非解朊栖热菌(Thermus nonproteolyticus Cai & Yangsp.nov.)。以菌株 HG-42为模式株,保藏于中国科学院微生物研究所。

21 strains of gram-negative nonsporeforming thermophilio rods were isolatedfrom hot springs of Yangjiang,Dianbai and Shaoguan in Guangdong.All the iso-lates can produce L-LDH.Their phenotypic features,homology and G+C mol%of deoxyribonucleic acid suggest that these strains be included in genus Thermus.But they differ from the previously described species with no acid from glucoseand nonliquefaction of gelatin.Deoxyribonucleic acid relatedness studies showed 6representative strains of the group to be very highly related(range 80—93%),butonly 40—70% related to other species of Thermus.Taxonomatically,they form atight cluster.We propose the name Thermus nonproteolyticus sp.nov.for thiscluster by the property of nonproteolytion.