Genetic analysis of bacteriophages from clinical and environmental samples

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dc.contributor.advisor Prentice, Michael B. en Knapik, Kamila Z. 2014-02-10T16:50:24Z 2013 2014
dc.identifier.citation Knapik, K. Z. 2013. Genetic analysis of bacteriophages from clinical and environmental samples. PhD Thesis, University College Cork. en
dc.identifier.endpage 209
dc.description.abstract Bacteriophages, viruses infecting bacteria, are uniformly present in any location where there are high numbers of bacteria, both in the external environment and the human body. Knowledge of their diversity is limited by the difficulty to culture the host species and by the lack of the universal marker gene present in all viruses. Metagenomics is a powerful tool that can be used to analyse viral communities in their natural environments. The aim of this study was to investigate diverse populations of uncultured viruses from clinical (a sputum of patient with cystic fibrosis, CF) and environmental samples (a sludge from a dairy food wastewater treatment plant) containing rich bacterial populations using genetic and metagenomic analyses. Metagenomic sequencing of viruses obtained from these samples revealed that the majority of the metagenomic reads (97-99%) were novel when compared to the NCBI protein database using BLAST. A large proportion of assembled contigs were assignable as novel phages or uncharacterised prophages, the next largest assignable group being single-stranded eukaryotic virus genomes. Sputum from a cystic fibrosis patient contained DNA typical of phages of bacteria that are traditionally involved in CF lung infections and other bacteria that are part of the normal oral flora. The only eukaryotic virus detected in the CF sputum was Torque Teno virus (TTV). A substantial number of assigned sequences from dairy wastewater could be affiliated with phages of bacteria that are typically found in the soil and aquatic environments, including wastewater. Eukaryotic viral sequences were dominated by plant pathogens from the Geminiviridae and Nanoviridae families, and animal pathogens from the Circoviridae family. Antibiotic resistance genes were detected in both metagenomes suggesting phages could be a source for transmissible antimicrobial resistance. Overall, diversity of viruses in the CF sputum was low, with 89 distinct viral genotypes predicted, and higher (409 genotypes) in the wastewater. Function-based screening of a metagenomic library constructed from DNA extracted from dairy food wastewater viruses revealed candidate promoter sequences that have ability to drive expression of GFP in a promoter-trap vector in Escherichia coli. The majority of the cloned DNA sequences selected by the assay were related to ssDNA circular eukaryotic viruses and phages which formed a minority of the metagenome assembly, and many lacked any significant homology to known database sequences. Natural diversity of bacteriophages in wastewater samples was also examined by PCR amplification of the major capsid protein sequences, conserved within T4-type bacteriophages from Myoviridae family. Phylogenetic analysis of capsid sequences revealed that dairy wastewater contained mainly diverse and uncharacterized phages, while some showed a high level of similarity with phages from geographically distant environments. en
dc.description.sponsorship Microbiology, College of Science, Engineering and Food Science, University College Cork en
dc.format.mimetype application/pdf en
dc.language.iso en en
dc.publisher University College Cork en
dc.rights © 2013, Kamila Z. Knapik en
dc.rights.uri en
dc.subject Bacteriophage en
dc.subject Virus en
dc.subject Metagenomics en
dc.subject.lcsh Microbial genomics en
dc.subject.lcsh Bacteriophages--Genetics en
dc.title Genetic analysis of bacteriophages from clinical and environmental samples en
dc.type Doctoral thesis en
dc.type.qualificationlevel Doctoral en
dc.type.qualificationname PhD (Science) en
dc.internal.availability Full text not available en
dc.description.version Accepted Version
dc.contributor.funder Microbiology, College of Science, Engineering and Food Science, University College Cork en
dc.description.status Not peer reviewed en Microbiology en
dc.check.reason This thesis is due for publication or the author is actively seeking to publish this material en
dc.check.opt-out No en
dc.thesis.opt-out true
dc.check.entireThesis Entire Thesis Restricted
dc.check.embargoformat Both hard copy thesis and e-thesis en
dc.internal.conferring Spring Conferring 2014 en

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© 2013, Kamila Z. Knapik Except where otherwise noted, this item's license is described as © 2013, Kamila Z. Knapik
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