Institute of Microbiology, Russian Academy of Sciences, Prospect 60-letiya Oktyabrya 7/2, 117312 Moscow, Russia.
Int J Syst Evol Microbiol. 2009 Dec;59(Pt 12):3116-22. doi: 10.1099/ijs.0.010355-0. Epub 2009 Jul 30.
An anaerobic acidophilic, hyperthermophilic archaeon, designated strain 345-15(T), was isolated from an acidic hot spring of Kamchatka (Russia). Cells of strain 345-15(T) were regular or irregular cocci, 1-2 mum in diameter, with flagella. Strain 345-15(T) grew optimally at 80-85 degrees C and pH 3.5-4.0 and fermented a wide range of carbohydrates, including polysaccharides. Acetate, ethanol and lactate were the fermentation products. Growth was stimulated by elemental sulfur and thiosulfate, which were reduced to hydrogen sulfide. The G+C content of the DNA was 54.5 mol%. The 16S rRNA gene sequence analysis indicated that strain 345-15(T) belonged to the genus Acidilobus. The level of DNA-DNA hybridization between strain 345-15(T) and Acidilobus aceticus 1904(T) was 61 %. Thus, strain 345-15(T) was considered as representing a novel species of the genus Acidilobus, with the name Acidilobus saccharovorans sp. nov. (type strain, 345-15(T)=DSM 16705(T)=VKM B-2471(T)), which shared the main morphological and physiological properties of the genus but differed by the presence of flagella and the spectrum of substrates utilized. Phylogenetic analysis showed that the genus Acidilobus, with its species Acidilobus aceticus, Acidilobus saccharovorans sp. nov. and 'Acidilobus sulfurireducens', and the genus Caldisphaera, represented by Caldisphaera lagunensis and 'Caldisphaera draconis', formed a separate cluster that adjoins the cluster formed by the species of the order Desulfurococcales. Members of the Acidilobus-Caldisphaera cluster are thermophilic, organotrophic anaerobic cocci that can be distinguished from all species of the order Desulfurococcales on the basis of acidophily. Based on these considerations, we propose a new family, Acidilobaceae fam. nov., to accommodate the subcluster of hyperthermophiles represented by the genus Acidilobus, a new family, Caldisphaeraceae fam. nov., for the subcluster of extreme thermophiles represented by the genus Caldisphaera, and a new order, Acidilobales ord. nov., to accommodate the two new families.
一种厌氧嗜酸、嗜热古菌，命名为菌株 345-15(T)，从俄罗斯堪察加的一个酸性温泉中分离得到。菌株 345-15(T)的细胞呈规则或不规则的球菌，直径 1-2 微米，有鞭毛。菌株 345-15(T)在 80-85°C 和 pH3.5-4.0 下生长最佳，并能发酵广泛的碳水化合物，包括多糖。乙酸盐、乙醇和乳酸是发酵产物。元素硫和硫代硫酸盐的刺激生长，这些物质被还原为硫化氢。DNA 的 G+C 含量为 54.5mol%。16S rRNA 基因序列分析表明，菌株 345-15(T)属于嗜酸杆菌属。菌株 345-15(T)与嗜酸杆菌 1904(T)之间的 DNA-DNA 杂交水平为 61%。因此，菌株 345-15(T)被认为代表了嗜酸杆菌属的一个新种，命名为嗜酸蔗糖杆菌新种(模式菌株 345-15(T)=DSM 16705(T)=VKM B-2471(T))，它具有该属的主要形态和生理特性，但有鞭毛和利用底物的谱不同。系统发育分析表明，嗜酸杆菌属及其种嗜酸杆菌、嗜酸蔗糖杆菌新种和“嗜酸硫还原菌”以及 Caldisphaera 属，以拉古纳氏 Caldisphaera lagunensis 和“巨龙 Caldisphaera draconis”为代表，形成一个单独的聚类，与脱硫球菌目物种形成的聚类相邻。嗜酸杆菌- Caldisphaera 聚类的成员是嗜热、有机营养的厌氧球菌，可根据嗜酸特性与脱硫球菌目所有物种区分开来。基于这些考虑，我们提出了一个新的科，即嗜酸杆菌科 fam. nov.，以容纳由嗜酸杆菌属代表的高温亚群；一个新的科，Caldisphaeraceae fam. nov.，以容纳由 Caldisphaera 属代表的极端高温亚群；以及一个新的目，Acidilobales ord. nov.，以容纳这两个新的科。
