Novel Oligotrophic Bacteria from the Deep Subsurface Phylogenetically Related to Plastids

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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.