How hosts cope with a major threat in the ocean: Pipefish - Vibrio immunological and genotypic interactions.

Keller, Isabel (2011) How hosts cope with a major threat in the ocean: Pipefish - Vibrio immunological and genotypic interactions. (Master thesis), Christian-Albrechts-Universität, Kiel, Germany, 73 pp.

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Abstract

The coevolution of hosts and parasites is one of the most prominent examples describing evolution in action. One of the manifold theories in the field of host-parasite interaction is local adaptation. Local adaptation evolves due to a difference in the evolutionary potential of host and parasite and suggests that a parasite genotype is better adapted to a sympatric (locally common) than to an allopatric (foreign) host genotype. Research has mainly focused on the investigation of adaption of parasites to their local hosts. In this study, however, I tried to establish the potential of host to adapt to their sympatric parasites. I here investigated local adaptation using a variety of pathogenic Vibrio strains and as host the pipefish Syngnathus typhle from four different locations along a north-south gradient. For all four habitats (Sweden, Denmark, Germany and Italy) the structure of the Vibrio strain community was characterized in a phylogeny. In addition, in two in vitro experiments local adaptation of the host to its potential sympatric or allopatric pathogens was investigated. Local adaptation has been studied by checking the antimicrobial activity of pipefish plasma to a subset of Vibrio strains isolated from all four habitats. Furthermore, differences in pipefish immune pararneters, such as rnonocyte to lyrnphocyte ratio, cell cycle analysis and phagocytosis capacity, have been deterrnined along the N orth-South gradient by flow cytornetry and lucigenin assays. Inhibition zone assays show that pipefish plasrna has a higher potential to clear bacterial growth of syrnpathric Vibrio strains than to clear allopatric strains in rnost interations tested. This indicates pipefish to be locally adapted to the rnajority of their syrnpatric parasites. However, in Sweden, were natural Vibrio prevalence was low during sarnpling, fish show the lowest potential of clearing not only their allopatric but even their syrnpatric Vibrio strains. The immune competence of pipefish differs arnong the four locations. Cell counts suggest that the Italian fish have the highest relative nurnber of lymphocytes, whereas cells in Swedish fishes where rnost active. Gerrnan fish have the highest phagocytosis activity.

Document Type: Thesis (Master thesis)
Thesis Advisor: Reusch, Thorsten B. H. and Roth, Olivia
Keywords: Marine Biology; host - parasite interaction; Vibrio; Syngnathus Typhle
Subjects: Course of study: MSc Biological Oceanography
Research affiliation: OceanRep > GEOMAR > FB3 Marine Ecology > FB3-EV Marine Evolutionary Ecology
Date Deposited: 15 Sep 2011 12:01
Last Modified: 07 Jan 2022 13:17
URI: https://oceanrep.geomar.de/id/eprint/12148

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