CU and the CDC

Legionella is a gram-negative genus of bacteria that is the cause of Legionnaires disease. Currently, 50 species and 70 serogroups of Legionella have been identified. The Center for Disease Control (CDC) in Atlanta maintains a bank of identified and unidentified Legionella samples. The availability of sequencing technologies has increased since many samples were collected allowing for identification of many previously unidentifiable isolates. We received 68 unidentified samples from the CDC. A sequence based typing scheme was used for characterization. Genomic DNA was extracted from samples and polymerase chain reactionwas performed on the 16S and mip genes. These samples were then sequenced at Clemson University Genomics Institute. Currently, we have identified several samples which were previously undescribed. Once a sample is identified as novel, characterization through sequencing other genes along with morphological and biochemical assays will be conducted. As a collaborative project, regular meetings occur with scientists from the CDC. Characterization of novel strains expands this lab\u27s ability to conduct outbreak analysis and risk assessment along with expanding our knowledge of the pathogen

Parasite infection rather than tactile stimulation is the proximate cause of cleaning behaviour in reef fish.

Cleaning behaviour is a popular example of non-kin cooperation. However, quantitative support for this is generally sparse and the alternative, that cleaners are parasitic, has also been proposed. Although the behaviour involves some of the most complex and highly developed interspecific communication signals known, the proximate causal factors for why clients seek cleaners are controversial. However, this information is essential to understanding the evolution of cleaning. I tested whether clients seek cleaners in response to parasite infection or whether clients seek cleaners for tactile stimulation regardless of parasite load. Parasite loads on client fish were manipulated and clients exposed to cleaner fish and control fish behind glass. I found that parasitized client fish spent more time than unparasitized fish next to a cleaner fish. In addition, parasitized clients spent more time next to cleaners than next to control fish, whereas unparasitized fish were not attracted to cleaners. This study shows, I believe for the first time, which is somewhat surprising, that parasite infection alone causes clients to seek cleaning by cleaners and provides insight into how this behaviour evolved

Honesty and cheating in cleaning symbioses: evolutionarily stable strategies defined by variable pay-offs.

Game-theory models have indicated that the evolution of mixed strategies of cheating and honesty in many mutualisms is unlikely. Moreover, the mutualistic nature of interspecific interactions has often been difficult to demonstrate empirically. We present a game-theory analysis that addresses these issues using cleaning symbioses among fishes as a model system. We show that the assumption of constant pay-offs in existing models prevents the evolution of evolutionarily stable mixed strategies of cheating and honesty. However, when interaction pay-offs are assumed to be density dependent, mixed strategies of cheating and honesty become possible. In nature, cheating by clients often takes the form of retaliation by clients against cheating cleaners, and we show that mixed strategies of cheating and honesty evolve within the cleaner population when clients retaliate. The dynamics of strategies include both negative and positive effects of interactions, as well as density-dependent interactions. Consequently, the effects of perturbations to the model are nonlinear. In particular, we show that under certain conditions the removal of cleaners may have little impact on client populations. This indicates that the underlying mutualistic nature of some interspecific interactions may be difficult to demonstrate using simple manipulation experiments