Transdisciplinary Research Integration Center, 4–3–13 Toranomon, Minato-ku, Tokyo 105–0001, Japan.
Microbes Environ. 2010;25(3):171-82. doi: 10.1264/jsme2.me10119.
To clarify altitudinal changes in the bacterial community on Gulkana Glacier in Alaska, we analyzed bacterial 16S rRNA gene by low-cycle PCR amplification, denaturing gradient gel electrophoresis (DGGE), and culturing in a snowmelt medium at 4°C. Low-cycle PCR-based cloning revealed the presence of 100 bacterial OTUs; however, 41 OTUs were identified only in a single clone, suggesting that their abundance was limited because of difficulty in predominating on the glacier. In contrast, 17 major OTUs accounted for 57-87% of the clone library at each site, suggesting that they accounted for the major part of the bacteria on the glacier. In addition, five of the 17 OTUs were included in the 21 OTUs cultured in the snowmelt medium. Based on the dominant phylotypes and DGGE results, the bacterial community on the glacier could be divided into three types, corresponding to the snow-covered, snow- and ice-covered, and bare-ice areas of the glacier. Our results suggest that a relatively limited number of bacteria predominate and that each phylotype is adapted to a distinct set of conditions on the glacier.
为了阐明阿拉斯加古尔卡纳冰川上细菌群落的海拔变化，我们通过低循环 PCR 扩增、变性梯度凝胶电泳（DGGE）和在 4°C 的融雪中培养基中进行培养来分析细菌 16S rRNA 基因。基于低循环 PCR 的克隆揭示了存在 100 个细菌 OTUs；然而，只有在单个克隆中鉴定出 41 个 OTUs，表明由于在冰川上占优势的难度，它们的丰度受到限制。相比之下，在每个地点，17 个主要 OTUs占克隆文库的 57-87%，表明它们占冰川上细菌的主要部分。此外，在融雪中培养基中培养的 21 个 OTUs 中包含 5 个 OTUs。基于优势的系统发育型和 DGGE 结果，冰川上的细菌群落可以分为三种类型，分别对应于冰川的积雪覆盖、雪和冰覆盖以及无冰区。我们的结果表明，相对数量有限的细菌占主导地位，每个系统发育型都适应于冰川上的一组独特条件。
