Isolation and characterization of soil bacteria that define Teniglobus gen. nov., in the phylum Acidobacteria
Isolation and characterization of soil bacteria that define Teniglobus gen. nov., in the phylum Acidobacteria
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DOI：
10.1128/aem.02140-06
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发表时间：
2007-04-01
影响因子：
4.4
通讯作者：
Schmidt, Thomas M.
中科院分区：
文献类型：
--
作者：
Eichorst, Stephanie A.;Breznak, John A.;Schmidt, Thomas M.
酸杆菌门中的细菌在土壤中广泛分布和丰富，但由于缺乏培养的代表，人们对它们的生态作用知之甚少。在密歇根州立大学凯洛格生物站长期生态研究场地进行的一项关于酸性细菌多样性的分子调查中，在一个从未耕作的演替植物群落中，27%的酸性细菌16S rRNA基因克隆属于亚纲1，其相对丰度与土壤pH成反比。从这些从未耕作的土壤中分离出I亚组菌株，使用低营养的培养基，在二氧化碳浓度升高的情况下培养3-4周，从而产生与菌株的最适pH值(在5-6之间)相匹配的轻微酸化的培养基。菌落直径约1毫米，白色或粉红色，后者是由于一种类胡萝卜素(S)在20%的氧气中优先合成的，而不是2%的氧气。菌株是革兰氏阴性，需氧，化学有机营养，无菌杆，产生细胞外基质。所有菌株都含有一个或两个16S rRNA编码基因的拷贝，加上相对较慢的倍增时间(在约23摄氏度下10至15小时)，暗示着一种寡营养的生活方式。其中6个菌株彼此足够相似，但与以前命名的酸杆菌截然不同，因此有理由创建一个新属--Terriglobus，其中Terriglobus roseus被定义为模式种。土豆的生理营养特性与其在土壤中广泛分布的潜力是一致的。
Bacteria in the phylum Acidobacteria are widely distributed and abundant in soils, but their ecological roles are poorly understood, owing in part to a paucity of cultured representatives. In a molecular survey of acidobacterial diversity at the Michigan State University Kellogg Biological Station Long-Term Ecological Research site, 27% of acidobacterial 16S rRNA gene clones in a never-tilled, successional plant community belonged to subdivision 1, whose relative abundance varied inversely with soil pH. Strains of subdivision I were isolated from these never-tilled soils using low-nutrient medium incubated for 3 to 4 weeks under elevated levels of carbon dioxide, which resulted in a slightly acidified medium that matched the pH optima of the strains (between 5 and 6). Colonies were approximately 1 mm in diameter and either white or pink, the latter due to a carotenoid(s) that was synthesized preferentially under 20% instead of 2% oxygen. Strains were gram-negative, aerobic, chemo-organotrophic, nomnotile rods that produced an extracellular matrix. All strains contained either one or two copies of the 16S rRNA encoding gene, which along with a relatively slow doubling time (10 to 15 h at ca. 23 degrees C) is suggestive of an oligotrophic lifestyle. Six of the strains are sufficiently similar to one another, but distinct from previously named Acidobacteria, to warrant creation of a new genus, Terriglobus, with Terriglobus roseus defined as the type species. The physiological and nutritional characteristics of Terriglobus are consistent with its potential widespread distribution in soil.