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Phages of highly pathogenic bacteria represent an area of growing interest for bacterial detection and identification and subspecies typing, as well as for phage therapy and environmental decontamination. Eight new phages—YpEc56, YpEc56D, YpEc57, YpEe58, YpEc1, YpEc2, YpEc11, and YpYeO9—expressing lytic activity towards Yersinia pestis revealed a virion morphology consistent with the Podoviridae morphotype. These phages lyse all 68 strains from 2 different sets of Y. pestis isolates, thus limiting their potential application for subtyping of Y. pestis strains but making them rather promising in terms of infection control. Two phages—YpYeO9 and YpEc11—were selected for detailed studies based on their source of isolation and lytic cross activity towards other Enterobacteriaceae. The full genome sequencing demonstrated the virulent nature of new phages. Phage YpYeO9 was identified as a member of the Teseptimavirus genus and YpEc11 was identified as a member of the Helsettvirus genus, thereby representing new species. A bacterial challenge assay in liquid microcosm with a YpYeO9/YpEc11 phage mixture showed elimination of Y. pestis EV76 during 4 h at a P/B ratio of 1000:1. These results, in combination with high lysis stability results of phages in liquid culture, the low frequency of formation of phage resistant mutants, and their viability under different physical–chemical factors indicate their potential for their practical use as an antibacterial mean.

Phage therapy can be an effective alternative to standard antimicrobial chemotherapy for control of

Viruses have the greatest abundance and highest genetic diversity in marine ecosystems. The interactions between viruses and their hosts is one of the hot spots of marine ecology. Besides their important role in various ecosystems, viruses, especially bacteriophages and their gene pool, are of enormous interest for the development of new gene products with high innovation value. Various studies have been conducted in diverse ecosystems to understand microbial diversity and phage&ndash, host interactions, however, the Black Sea, especially the Eastern coastal area, remains among the least studied ecosystems in this regard. This study was aimed at to fill this gap by analyzing microbial diversity and bacteriophage&ndash, host interactions in the waters of Eastern Black Sea using a metagenomic approach. To this end, prokaryotic and viral metagenomic DNA from two sampling sites, Poti and Gonio, were sequenced on the Illumina Miseq platform and taxonomic and functional profiles of the metagenomes were obtained using various bioinformatics tools. Our metagenomics analyses allowed us to identify the microbial communities, with Proteobacteria, Cyanobacteria, Actinibacteria, and Firmicutes found to be the most dominant bacterial phyla and Synechococcus and Candidatus Pelagibacter phages found to be the most dominant viral groups in the Black Sea. As minor groups, putative phages specific to human pathogens were identified in the metagenomes. We also characterized interactions between the phages and prokaryotic communities by determining clustered regularly interspaced short palindromic repeats (CRISPR), prophage-like sequences, and integrase/excisionase sequences in the metagenomes, along with identification of putative horizontally transferred genes in the viral contigs. In addition, in the viral contig sequences related to peptidoglycan lytic activity were identified as well. This is the first study on phage and prokaryote diversity and their interactions in the Eastern coastal area of the Black Sea using a metagenomic approach.

Social entrepreneurship as an event appeared in XIX century. However, the emergence, development, forms of origin, scale of activity and speed of dissemination of social entrepreneurship are uneven across countries due to objective institutional factors. Based on the analysis of the emergence and development of social entrepreneurship worldwide, we can say that social entrepreneurship is a global event, which, on the one hand, extends to all regions of the world, on the other hand, has its national forms and characteristics depending on the degree of development of institutions, traditions and cultures in any one country. In generalizing the key trends in the development of social entrepreneurship worldwide, we can infer that the temporal and geographical frameworks for the spread of social entrepreneurship are driven by objective preconditions. Historical, political and socio-economic factors have influenced the period of formation of social entrepreneurial firms, organizational-legal forms and the intensity of the spread of social entrepreneurship in different regions of the world. The article discusses the regional features of social entrepreneurship development not only in countries where it has an established tradition, but also in countries where social entrepreneurship is starting to emerge. The main objective of the presented analysis is, on the one hand, to show the global scale of this event worldwide, and on the other, to reveal its national features.

Summary Three freshwater lakes, Lisi Lake, Kumisi Lake and Tbilisi Sea, near Tbilisi, Georgia, were studied from January 2006 to December 2007 to determine the presence of Vibrio cholerae employing both bacteriological culture method and direct detection methods, namely PCR and direct fluorescent antibody (DFA). For PCR, DNA extracted from water samples was tested for presence of V. cholerae and genes coding for selected virulence factors. Vibrio cholerae non-O1/non-O139 was routinely isolated by culture from all three lakes; whereas V. cholerae O1 and O139 were not. Water samples collected during the summer months from Lisi Lake and Kumisi Lake were positive for both V. cholerae and V. cholerae ctxA, tcpA, zot, ompU and toxR by PCR. Water samples collected during the same period from both Lisi and Kumisi Lake were also positive for V. cholerae serogroup O1 by DFA. All of the samples were negative for V. cholerae serotype O139. The results of this study provide evidence for an environmental presence of toxigenic V. cholerae O1, which may represent a potential source of illness as these lakes serve as recreational water in Tbilisi, Georgia.

Knowledge of both the packaging of the linear, double-stranded (ds)DNA in bacteriophages and its subsequent release into the bacterial host is vital to our understanding of phage infection. There is now strong evidence that packaging requires a powerful rotary motor fuelled by ATP. From thermodynamic studies, however, it has been proposed that, at least for those viruses with a contractile tail, the dsDNA ejection from the phage head is a relatively simple physical process that does not require cellular energy and is facilitated by the difference in the conditions of the medium in the environments inside and outside the head. In this case, there should be no enthalpic effects associated with the dehiscence of the capsid and no destruction of it or the other structural elements of the phage. For the present study of temperature-induced phage dehiscence, we used a newly discovered phage with a contractile tail, named the Un (unknown) bacteriophage. Evidence is given of its characteristics in terms of ultrastructural morphology, serological parameters, host range and interaction with host cell. These show that, although it has similarities with the T-even phages and, in particular, the DDVI phage, it appears to be a new type. Earlier viscometric studies with it had shown that the temperature-induced release of the capsid dsDNA was completed at 70 degrees C. In the present investigation, a concentrated suspension of purified phage was subjected to pycnometric analysis through the temperature range of 30 to 70 degrees C. This showed that a significant and abrupt increase in the phage partial volume takes place, which remarkably is in the order of threefold. Viscometric measurements over time at 72 degrees C gave a kinetic curve from which evidence it was suggested that the temperature-induced DNA release is similar to a second order phase transition. At the same time, data from differential scanning calorimetry over the same temperature range showed no enthalpic effect. Our results indicate that the ejection of DNA from the capsid tail is driven by an entropy change.

Three freshwater lakes, Lisi Lake, Kumisi Lake and Tbilisi Sea, near Tbilisi, Georgia, were studied from January 2006 to December 2007 to determine the presence of Vibrio cholerae employing both bacteriological culture method and direct detection methods, namely PCR and direct fluorescent antibody (DFA). For PCR, DNA extracted from water samples was tested for presence of V. cholerae and genes coding for selected virulence factors. Vibrio cholerae non-O1/non-O139 was routinely isolated by culture from all three lakes; whereas V. cholerae O1 and O139 were not. Water samples collected during the summer months from Lisi Lake and Kumisi Lake were positive for both V. cholerae and V. cholerae ctxA, tcpA, zot, ompU and toxR by PCR. Water samples collected during the same period from both Lisi and Kumisi Lake were also positive for V. cholerae serogroup O1 by DFA. All of the samples were negative for V. cholerae serotype O139. The results of this study provide evidence for an environmental presence of toxigenic V. cholerae O1, which may represent a potential source of illness as these lakes serve as recreational water in Tbilisi, Georgia.

Microbial safety of recreational water is one of the major human public health issues in developing countries. Three water bodies, the Tbilisi Sea, Kumisi and Lisi lakes, in the South Caucasus region near Tbilisi, Georgia, were monitored in 2006–2009 to determine microbiological quality using standard methods. Microbial pollution indicators were determined in parallel with phytoplankton abundance and measurement of a number of physical–chemical parameters. Kumisi Lake, a brackish water body in an active agricultural area, appeared to be the most polluted, whereas the Tbilisi Sea, a freshwater reservoir was the least polluted. High values for fecal indicators in all three lakes in summer and early autumn were revealed. In our study, total enterococci counts (TEC) appeared to be a better indicator than either fecal or total coliform counts for the evaluation of fresh and brackish microbial water quality. We found significant correlation between total Vibrio counts and TEC for all three water bodies. Prevalence of somatic coliphages and V. cholerae-specific phages as additional water pollution indicator significantly correlated with abundance of the host bacteria. Particular phytoplankton groups in the lakes responded to the changes of fecal indicators; however, no correlation was observed between dominant zooplankton taxonomic groups and microbial parameters.

The Ibis T5000 is a novel diagnostic platform that couples PCR and mass spectrometry. In this study, we developed an assay that can identify all known pathogenic Vibrio species and field-tested it using natural water samples from both freshwater lakes and the Georgian coastal zone of the Black Sea. Of the 278 total water samples screened, 9 different Vibrio species were detected, 114 (41%) samples were positive for V. cholerae , and 5 (0.8%) samples were positive for the cholera toxin A gene ( ctxA ). All ctxA -positive samples were from two freshwater lakes, and no ctxA -positive samples from any of the Black Sea sites were detected.