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Title: Molecular studies on the diversity of marine Prochlorococcus and their co-occurring phages in the Atlantic Ocean
Author: Jameson, Eleanor
ISNI:       0000 0001 3588 9661
Awarding Body: University of Warwick
Current Institution: University of Warwick
Date of Award: 2008
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Cyanobacteria of the genus Prochlorococcus are the most abundant photoautotrophs in the oceans. Prochlorococcus can be sub-divided into ecotypes that are genetically and physiologically diverse, which occupy different niches, with defined chemical and physical parameters. In this project environmental samples were collected during a north-south Atlantic transect cruise (AMT15) for the study of Prochlorococcus and Prochlorococcus-infecting viral diversity. Novel Prochlorococcus-specific primers were successfully developed to investigate Prochlorococcus microdiversity. When applied to the environmental samples these probes exposed high diversity in Prochlorococcus assemblages. Prochlorococcus microdiversity exhibited correlations to latitude and temperature, at the depth to which 14% of the surface light· levels penetrated. Phylogenetic analysis of these Prochlorococcus assemblages has revealed putatively novel lineages. Viruses that infect Prochlorococcus are abundant in the oceans and they are therefore likely to playa critical role in maintaining Prochlorococcus diversity. The analysis of environmental Prochlorococcus-infecting virus populations is still in its infancy, therefore viral isolation is important to understand the ecology of these viruses. The isolation of Prochlorococcus-infecting viruses has proven successful during this study. A podovirus was isolated from south Atlantic seawater samples. Given the unprecedentedly wide host of this isolate, podoviruses are likely to have exerted an influence on Prochlorococcus diversity, especially if they are present at high concentrations. To create genetic cut offs for the analysis cyanomyovirus diversity to a high resolution, existing g20 primers were successfully coupled with a novel in silico RFLP approach. The myoviral diversity revealed was higher than previously seen and putatively novel myovirallineages were identified. Myovirus diversity was variable between the Atlantic samples and showed no significant correlations to environmental parameters or cyanobacteria. The genetic diversity dynamics of both host and myoviral communities were correlated with environmental parameters. This analysis indicated that temperature and myoviral diversity had the greatest impact on Prochlorococcus diversity.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available