Project description:The SAR11 clade is one of the most abundant bacterioplankton groups in surface waters of most of the oceans and lakes. However, only 15 SAR11 phages have been isolated thus far, and only one of them belongs to the Myoviridae family (pelagimyophages). Here, we have analyzed 26 sequences of myophages that putatively infect the SAR11 clade. They have been retrieved by mining ca. 45 Gbp aquatic assembled cellular metagenomes and viromes. Most of the myophages were obtained from the cellular fraction (0.2 μm), indicating a bias against this type of virus in viromes. We have found the first myophages that putatively infect Candidatus Fonsibacter (freshwater SAR11) and another group putatively infecting bathypelagic SAR11 phylogroup Ic. The genomes have similar sizes and maintain overall synteny in spite of low average nucleotide identity values, revealing high similarity to marine cyanomyophages. Pelagimyophages recruited metagenomic reads widely from several locations but always much more from cellular metagenomes than from viromes, opposite to what happens with pelagipodophages. Comparing the genomes resulted in the identification of a hypervariable island that is related to host recognition. Interestingly, some genes in these islands could be related to host cell wall synthesis and coinfection avoidance. A cluster of curli-related proteins was widespread among the genomes, although its function is unclear.IMPORTANCE SAR11 clade members are among the most abundant bacteria on Earth. Their study is complicated by their great diversity and difficulties in being grown and manipulated in the laboratory. On the other hand, and due to their extraordinary abundance, metagenomic data sets provide enormous richness of information about these microbes. Given the major role played by phages in the lifestyle and evolution of prokaryotic cells, the contribution of several new bacteriophage genomes preying on this clade opens windows into the infection strategies and life cycle of its viruses. Such strategies could provide models of attack of large-genome phages preying on streamlined aquatic microbes.
Project description:Use of pyrosequencing to determine the effects of monochloramine treatment on Legionella and associated bacterial populations in a hospital hot water system
Project description:Bacterial 16S amplicon 454 pyrosequencing of environmental samples (vertebrate faeces, sediment, soil, surface water) to assess the potential of next generation sequencing methods for health related microbial water quality monitoring
Project description:In anaerobic digestion plants (ADP) homogenization of the feed, the fermenter content and the microbial communities represents a precondition for effective and robust biogas production,but also a major energy consumer. For a 850 m3 agricultural AD-P equipped with eight sampling ports we investigated whether different feeding and stirring regimes enable a sufficient homogenization of the microbial communities using metaproteome and TRFLP analysis. Systematic comparison of the samples by scatter plots and students t-test revealed only a limited number of slightly changed metaproteins, taxonomies and biological processes, indicating no systematic differences between the microbial communities in center and rim as well as between top and bottom. However, comparison of the amount of shared identified metaproteins between the sample ports showed minor variation, which might be correlated with the applied stirring strategy. In sum, the applied stirring and feeding conditionswere sufficient to homogenize the microbial communities in AD-Ps largely.