Lacey Rzodkiewicz and Rachael Kramp- Turcotte & Stephenson Labs
Lacey's Title:
"Exploring toxigenicity and system stability in harmful algal blooms"
Rachael's Title:
"Examining Skin Microbiome of Trinidadian guppy and its Role in Ectoparasite Infection Dynamics"
Monday, October 26, 2020
4:00 PM
Zoom Link:
https://pitt.zoom.us/j/99612467670
Meeting ID
996 1246 7670
Abstracts:
(Lacey Rzodkiewicz)
In the developing field of evolutionary ecotoxicology, systems involving naturally produced toxins are often neglected in favor of toxicants with anthropogenic origin despite providing a wealth of opportunity to study the ecological and evolutionary consequences of chemical stress. While allelochemicals and chemical defense are studied under ecological and evolutionary frameworks, I propose that these toxin systems may be discussed under evolutionary ecotoxicology as well. An idealized system is presented in harmful algal blooms (HABs), dense aggregates of cyanobacteria present in both toxigenic and nontoxigenic strains. The system allows us to measure toxigenicity of cyanobacterial focal populations while observing the interactions of the population and toxin with competitors and herbivores. I seek to begin addressing three questions using HABs as a study system. First, I will discuss the possibility of sufficient genetic variation for adaptation to cyanobacterial toxins existing in competitor populations, using duckweed species as a model given the promise of the taxa for bioremediation of HABs. Available preliminary data demonstrate that significant variation in growth and morphology existed among ten clonal lineages of Spirodela polyrhiza exposed to an ecologically relevant concentration of a cyanobacterial toxin, and investigations into additional variation are ongoing. Next, I will discuss the possibility of competition or herbivory acting as a greater driving force in toxigenicity selection. The question will be investigated both in the field and in a controlled microcosm environment. Lastly, I will suggest how the HAB system may be used to address questions of stability
(Rachael Kramp)
A host’s first line of defense against parasites, in the vast majority of animals, is its skin. Teleost fish skin is coated in mucus that shelters complex microbial communities that are generally well adapted to the epidermal surface. Fish ectoparasites spend much, if not all, of their life cycle on this microbially rich skin, directly interacting with microbes that could influence the interactions between host and parasite. Here, we tested whether the microbiome present on the host pre-infection could predict subsequent infection susceptibility to an ectoparasitic helminth. Using 16S rRNA community analysis, we studied the bacterial communities of Trinidadian guppies (Poecilia reticulata) and their correlations with Gyrodactylus turnbulli. We swabbed fish skin to inventory the skin microbiome before experimentally infecting them with G. turnbulli. We found that fish skin microbiome communities can predict infection severity. Additionally, we found that male and female guppies differed in their alpha diversity before infection with G. turnbulli, their defense against the parasites. Our results, therefore, suggest that the fish skin microbiome alters the host-parasite interactions during Gyrodactylus infection. Future experiments will test how environmental factors may alter the skin microbiome, improve or worsen infection outcomes for the host, and how parasites may respond to changing microbial communities