Improving the quantification of microbial cell abundances in subseafloor sediments through a combination of newly developed cell extraction and automated cell enumeration techniques

对海底深层生物圈的探索是IODP内进展最快的研究领域之一。最基本的参数之一是微生物生物量的总量及其随深度的分布。由于目前的方法缺乏敏感性，而且人工分析非常耗时，这一参数仍然不能令人满意地量化。申请人最近开发了一种新的细胞提取技术，通过半定量地从沉积物中去除细胞，允许使用更多的沉积物，从而允许更低的检测下限。由于每个样本上计数的细胞更多，因此计数统计数据显著改善，但代价是增加了处理时间。共同倡导者在自动样品处理领域的最新进展允许处理更多数量的样品。这两种技术的结合有可能通过更好的计数统计和更高的样本数量，特别是在极端缺乏细胞的环境中，极大地提高我们对微生物种群密度精细动态的理解。然而，将这两种技术结合起来并非易事，需要在细胞提取和自动计数方面进行仔细的修改。拟议的访问将用于制定这两种方法相结合的细节。

Exploration of the deep subseafloor biosphere is one of the most rapidly advancing fields of research within IODP. One the most fundamental parameters is the total amount of microbial biomass and its distribution with depth. This parameter can still not be quantified satisfactorily because of a lack of sensitivity of the current methods and the extremely time consuming manual analysis. The applicant recently developed a new cell extraction technique, which allows for a much lower detection limit by removing the cells semiquantitatively from the sediment, allowing more sediment to be used. Counting statistics improve significantly due to more cells being counted on each sample, however at the cost of increased processing time. Recent advances by the co-proponent in the field of automated sample processing allow for a much greater number of samples being processed. A combination of both techniques has the potential to greatly improve our understanding of the fine-scale dynamics of microbial population densities through better counting statistics and higher sample numbers, especially in extremely cell-poor environments. However, combining the two techniques is far from easy and requires careful modifications on both the cell extraction and the automated counting. The proposed visit will be used to work out the details for the combination of the two methods.