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作者 Kimes, Nikole E
書名 The Coral Microbiome: A Study in Structure, Function, and Temperature Influences
國際標準書號 9781124575056
book jacket
說明 387 p
附註 Source: Dissertation Abstracts International, Volume: 72-06, Section: B, page: 3209
Adviser: Pamela J. Morris
Thesis (Ph.D.)--Medical University of South Carolina, 2010
Coral reef ecosystems are the most diverse marine ecosystems on earth, and they provide global ecological (e.g., biodiversity, nutrient cycling, and storm protection) and economic (e.g., fishing, tourism and natural products) benefits. Unfortunately, these ecosystems are being degraded worldwide due to infectious disease, human activities, and climate change. The most dramatic decline has been observed in the Caribbean where up to 80% of coral cover has been lost over the last thirty years. Globally, it is estimated that 60% of coral cover worldwide will be lost by 2030. Disease is a major cause of the visable deterioration evidenced in the past twenty years, and research implicates the coral-associated microbial community as a key component in the disease process. Culture-dependent studies have led to the identification of individual coral pathogens; while culture-independent studies have established that coral-associated microbial communities change during disease. The objective of this dissertation project was two-fold. First was to investigate the microbiome structure and function of healthy and yellow band disease (YBD) Montastraea faveolata, an important reef-building coral in the Caribbean. We hypothesized that a shift in the phylogenetic structure of the microbial community associated with M. faveolata during YBD would result in an altered functional role fulfilled by the new community. To test this hypothesis, we sequenced the zooxanthellar, bacterial, and archaeal communities and identified functional genes using the Geochip 2.0 associated with healthy and YBD M. faveolata collected in March 2009. The results revealed differences in the phylogenteic and functional structure between healthy and YBD colonies, providing support for this hypothesis. The second objective was to investigate the influence of temperature on the coral microbiome and its potential role in coral disease. To examine temporal changes in the coral microbiome of healthy and YBD M. faveolata, we sequenced the zooxanthellar and bacterial communities associated with the same tagged healthy and YBD M. faveolata collected in September 2009. Our results showed a significant change in both microbial communities between March and September, suggesting that temporal changes (e.g., heat stress and UV) affect both communities. To elucidate the role of a temperature-dependent coral pathogen, Vibrio coralliilyticus, we used two-dimensional liquid chromatography coupled with tandem mass spectrometry to compare protein expression of virulence factors at 24 and 27°C. Our results indicated that temperature has a direct effect on V. coralliilyticus virulence factors, including quorum sensing (QS), motility, secretion, antibiotic resistance, and host degradation proteins. Because changes in growth do not correlate with the differential temperature expression, we hypothesized that V. coralliilyticus QS, a global regulatory system, is directly influenced by temperature, resulting in increased virulence factor production. Quorum signaling assays provided support for temperature influence on QS in V. coralliilvticus. The research presented in this dissertation suggests that the coral microbiome is a complex and dynamic entity that undergoes structural and functional changes in response to changing ecological parameters. Furthermore, temperature influences the microbial community dynamics through increased diversity to the overall structure of the microbiome as well as increased expression of virulence factors in V. coralliilyticus. In conclusion, we hypothesize that continued increases in temperature due to global climate change will result in destabilization of the coral microbiome and increased Vibrio-induced diseases
School code: 0122
Host Item Dissertation Abstracts International 72-06B
主題 Biology, Molecular
Biology, Microbiology
Environmental Sciences
Alt Author Medical University of South Carolina
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