Molecular Recognition in Biological Systems and Bioinformatics

Symbiosis

My lab studies the symbiosis between corals (Cnidaria:Hexacorallia:Scleractinia) and photosynthetic dinoflagellate symbionts (Alveolata: Dinophycea: Symbiodinium). This symbiosis provides the foundation and structure of the coral reef ecosystem, as well as significant contributions to global carbon and biogeochemical cycles. Given the importance of this symbiosis to the coral-algal holobiont and the reef ecosystem, understanding the mechanisms governing the establishment and long term maintenance of this symbiosis is essential.

One of the major aims of my lab is to identify the mechanisms and selective processes that lead a host species to establish a symbiosis with a particular symbiont strain. The establishment of the symbiosis is a cascade of cellular events, from cell signaling and cell recognition, that begins prior to initial uptake, to metabolic and other changes that occur as the final complement is established. These events reflect physical and metabolic interactions between a host and symbiont that are ultimately due to the associations between functional proteins (proteome) present in each organism. Mechanisms of host-symbiont recognition likely involve interactions between molecules present on the surface of both the symbiont and host cell and a survey of our EST data set has identified several gene members of signaling pathways that are known to be involved in innate immunity.

As a sister group to the exclusively parasitic apicomplexans, an understanding of mechanisms by which these dinoflagellates symbionts become establish within the host is expected to yield insights into apicomplexan infections.

We are approaching this aim from two perspectives, ecologic and genomic, with the specific goals of (1) determining if different symbiont strains differentially affect fitness of settled corals and (2) determining if genes regulating the measured fitness traits are differentially expressed in host and symbiont as the symbiont community within a host is winnowed to the final assemblage found in the adult host. To do this we are measuring traits that directly affect coral fitness (i.e. growth, survivorship, energy production) over the ontogeny of coral recruits that are experimentally infected with different symbiotic strains. In collaboration with colleagues at UC-Merced, we are using high throughput gene expression profiling to identify differentially expressed genes using the same experimental design. Together, these data will be used to validate or falsify the hypotheses that the final symbiont assemblage found in the adult host is determined by (a) host selection and/or (b) competition among symbionts.

Coral, octocoral, dinoflagellates (Symbiodinium)

Apicomplexan parasitic infections

• Microarrays
• QPCR
• Standard PCR and sequencing

A series of Symbiodinium isoclonal strains

Apicomplexan parasitic infections

http://www.geology.buffalo.edu/people/faculty/coffroth.shtml

http://www.nsm.buffalo.edu/Bio/burr/