Pettersson B, Lembke F, Hammer P, Stackebrandt E, Priest F G
Department of Biochemistry and Biotechnology, Royal Institute of Technology, Stockholm, Sweden.
Int J Syst Bacteriol. 1996 Jul;46(3):759-64. doi: 10.1099/00207713-46-3-759.
Bacteria that differentiate into highly heat-resistant endospores (HHRS strains) may survive ultrahigh-temperature treatment of milk and germinate in the final product. They do not noticeably spoil the milk and are nonpathogenic. The complete (>96%) 16S rRNA genes from three HHRS strains were identical, and phylogenetic analysis placed them alongside Bacillus firmus in the B. megaterium group of the genus Bacillus. Moreover, the approximately 550 nucleotides between regions U2 and U5 were invariant for seven HHRS strains. However, three cloned 16S rRNA genes from one HHRS strain, M215, showed marked size and sequence variations within the V1 and V2 regions. DNA reassociation assays confirmed the distinction between a reference HHRS strain and closely related members of the B. megaterium group, notably, B. firmus (30%), B. benzoevorans (28%), and B. circulans (20%). Ribotyping and pyrolysis mass spectrometry both indicated that the HHRS strains belong to a homogeneous, species-ranked taxon, an exception being strain TP1248, which is slightly atypical. The HHRS strains are unusual in that they grow poorly, if at all, on nutrient agar; good growth is obtained on brain heart infusion agar. On subculture, most HHRS strains form long, filamentous rods which stain unevenly in the Gram reaction. They are strictly aerobic and do not produce acid from sugars. We propose the name Bacillus sporothermodurans for these bacteria, which are phenotypically and phylogenetically distinct from other Bacillus species. The type strain is M215 (= DSMZ 10599).
分化为高度耐热芽孢的细菌（HHRS菌株）可能在牛奶的超高温处理中存活，并在最终产品中发芽。它们不会明显破坏牛奶，且无致病性。来自三个HHRS菌株的完整（>96%）16S rRNA基因相同，系统发育分析将它们与芽孢杆菌属巨大芽孢杆菌组中的坚强芽孢杆菌归为一类。此外，七个HHRS菌株在U2和U5区域之间的大约550个核苷酸是不变的。然而，来自一个HHRS菌株M215的三个克隆16S rRNA基因在V1和V2区域显示出明显的大小和序列变异。DNA重结合分析证实了参考HHRS菌株与巨大芽孢杆菌组密切相关成员之间的区别，特别是坚强芽孢杆菌（30%）、苯甲酸芽孢杆菌（28%）和环状芽孢杆菌（20%）。核糖体分型和热解质谱分析均表明，HHRS菌株属于一个同质的、具有种级别的分类单元，但菌株TP1248略有非典型。HHRS菌株的不同寻常之处在于，它们在营养琼脂上生长不良（如果生长的话）；在脑心浸液琼脂上生长良好。传代培养时，大多数HHRS菌株形成长的丝状杆菌，革兰氏反应染色不均匀。它们严格需氧，不利用糖类产酸。我们提议将这些细菌命名为嗜热栖芽孢杆菌，它们在表型和系统发育上与其他芽孢杆菌属物种不同。模式菌株是M215（=DSMZ 10599）。
