NASA Astrobiology Institute (NAI)

The goal of this project is to survey the microbial life that comprises a hypersaline microbial mat at Guerrero Negro, Mexico using culture independent technology (ribosomal and other gene sequences). The results have expanded significantly our knowledge of microbial diversity, bacterial, archaeal and eucaryotic.

In the main area of research, microbiology of hypersaline ecosystems, substantial progress was made in discovering new microbes including eucaryotes, in the Guerrero Negro hypersaline mat system. By partnering with the Joint Genome Institute (DOE) we have conducted the largest survey so far of environmental diversity, expanding significantly the ribosomal RNA tree of life, particularly among bacteria. Several publications have previously been reported and others are being prepared based on those findings.

Beyond the sequence census, the Guerrero Negro project has gone far to expanding the tree of life, not only in terms of numbers, but also the diversity of representation in calculations to extract computationally the actual topology of the tree of life, still unresolved at the deepest levels. The novel diversity provides many additional “survey points” with which to contruct the map of the course of evolution on Earth.

Taking advantage of the CU-Boulder high voltage electron microscopy facility, we have conducted a high resolution morphological study by electron tomography of the organisms Salmonella typhimurium, a bacterium, and Sulfolobus solfataricus, an archaeon. The study provides direct comparison between bacterial and an archaeal cell structure, which contrast significantly. Several morphologically conspicuous cellular features of unknown function were seen in S. solfataricus, providing a background for further studies.