Research Profile:

Our laboratory carries out research in two areas. In one, we study the structure and mechanism of activity of the Halophilic microalgae Dunaliella. In the second, we explore naturally occurring communities of marine microalgae isolation and identification through using molecular methods that sidestep the need to cultivate the organisms. Although these two research areas might seem disparate, they overlap substantially in techniques and in a phylogenetic-comparative approach.

In the second project area, comparisons of ribosomal RNA (rRNA) sequences are used to explore naturally occurring microbial ecosystems. Little is known about the natural microbial world because biologists have always had to cultivate organisms in order to study them, and typically <0.1%>of organisms observed microscopically in the environment can be cultivated. Consequently, we have been developing a suite of molecular techniques, based on the molecular phylogeny of 18S rRNA, that allow us to characterize naturally occurring organisms without cultivation. Comparisons of 18S rRNA sequences can be used to generate evolutionary trees that can be used as a quantitative framework in which to identify unknown organisms.

Future work plan:

In natural population analyses, rRNA genes are obtained by cloning from DNA isolated directly from the environment. Sequence and phylogenetic analyses of the rRNA genes incisively relate unknown organisms to known ones. Some properties of the unknown organisms can be inferred from the properties of their relatives. The sequences can be used to design hybridization probes for further studies of interesting organisms, in the environment or laboratory. We have developed these techniques in the context of studying several types of ecosystems.