Browsing by Author "Timsit, Édouard"
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Item Open Access Myoviridae as Part of Cattle Fecal Microbiome(2019-03-18) Rincón García, Mónica; van der Meer, Frank; Bachofen, Claudia; Orsel, Karin; Timsit, Édouard; Hynes, Michael F.Double-stranded deoxyribonucleic acid (dsDNA) phages from the order of Caudovirales are the most abundant viruses in the microbiome of the mammalian digestive tract. There is increasing awareness of the role of phages in modulating bacterial composition in digestive compartments. Mammalian digestive microbiomes are generally dominated by members of the Bacteroidetes and Firmicutes phyla. Moreover, phages from the Siphoviridae family (order Caudovirales) are the most abundant members in the rumen of cattle and large intestine of humans, horses and pigs. However, there is a knowledge gap regarding composition of the virome in the large intestine of cattle. To facilitate these studies, suitable methods to analyze bovine fecal sample for virus content are needed. Therefore, the objective of this thesis was to establish appropriate methodologies and evaluate fecal samples from various sources. Two virus particle purification (VPP) procedures, namely filtration and cesium chloride (CsCl) ultracentrifugation were compared, using electron microscopy (EM), polymerase chain reaction (PCR) and metagenomic analyses. In total, 39 cattle fecal samples were processed. Metagenomic analysis was the most suitable methodology for measuring relative abundance (RA) and diversity of Myoviridae in fecal samples from two beef and two dairy cattle. Overall, numbers of phage members of the order Caudovirales was higher compared to other dsDNA viruses, with Myoviridae being the most abundant family within this order. Furthermore, a functional procedure to estimate total viral dsDNA virome in feces was developed. In conclusion, this thesis includes methods to detect and characterize phages in cattle feces, with generation of novel data that improve understanding of viral diversity in fecal microbiomes.