Novel Oligotrophic Bacteria from the Deep Subsurface Phylogenetically Related to Plastids

小行星9707224 在今天地球上被认为存在的100多万种细菌中，只有几千种被仔细命名和描述。 这些未描述的生命形式的特征可能与已知的生命形式相当不同。 最近从沉积于约1000年的沉积岩中分离出了一些细菌菌株。9500万年前，目前位于地球表面以下150-200米处。 其中一些菌株含有代表小亚基核糖体RNA基因的DNA序列，与藻类和陆地植物的叶绿体最相似，而不是其他细菌。 这些序列是细菌本身的，还是来自其他来源？ 如果是原生的，这些细菌（令人惊讶地）与质体密切相关吗？ 如果这些基因不是原生的，那么它们是如何进入并留在细菌中，与已经存在的类似基因竞争的呢？ 为了回答这些和相关的问题，Tery Marsh和Frans de Bruijn将对这些深层的培养细菌进行分子生物学研究，这些细菌似乎带有类似质体的DNA序列。 他们将试图确定类质体基因是这些细菌的主要DNA分子的一部分还是携带在较小的片段上。 他们将对这些细菌的其他基因进行测序，以确定它们是否也类似于叶绿体中的对应基因。 他们还将寻找使用荧光标记标记这些细菌和来自相同或相似栖息地的其他细菌的方法。

9707224 MARSH Of the more than a million species of bacteria thought to exist on Earth today, only several thousand have been named and described carefully. The characteristics of these undescribed lifeforms may be rather different from those that are known. Strains of bacteria have been isolated recently from sedimentary rocks deposited ca. 95 million years ago and currently lying 150-200 meters below the earthOs surface. Some of these strains contain DNA sequences, representing the small-subunit ribosomal RNA gene, that most closely resemble those of the chloroplasts of algae and land plants, not other bacteria. Are these sequences native to the bacteria, or did they come from some other source? If native, are these bacteria (surprisingly) closely related to plastids? If not native, how did these genes get into, and stay within, the bacteria, in competition with the similar genes already there? To answer these and related questions, Tery Marsh and Frans de Bruijn will conduct molecular biological research on cultivated bacteria from these deep strata that appear to bear plastid-like DNA sequences. They will attempt to determine whether the plastid-like genes are part of the major (OgenomicO) DNA molecules of these bacteria or are carried on smaller fragments (OplasmidsO). They will sequence additional genes from these bacteria to determine whether they also resemble counterpart genes in chloroplasts. They will also look for ways to label these bacteria and others from the same or similar habitats, using fluorescent markers.