Positive Signature-Tagged Mutagenesis in Pseudomonas aeruginosa: Tracking Patho-Adaptive Mutations Promoting Airways Chronic Infection

The opportunistic pathogen Pseudomonas aeruginosa can establish life-long chronic infections in the airways of cystic fibrosis (CF) patients. Persistent lifestyle is established with P. aeruginosa patho-adaptive variants, which are clonal with the initially-acquired strains. Several reports indicated that P. aeruginosa adapts by loss-of-function mutations which enhance fitness in CF airways and sustain its clonal expansion during chronic infection. To validate this model of P. aeruginosa adaptation to CF airways and to identify novel genes involved in this microevolution, we designed a novel approach of positive-selection screening by PCR-based signature-tagged mutagenesis (Pos-STM) in a murine model of chronic airways infection. A systematic positive-selection scheme using sequential rounds of in vivo screenings for bacterial maintenance, as opposed to elimination, generated a list of genes whose inactivation increased the colonization and persistence in chronic airways infection. The phenotypes associated to these Pos-STM mutations reflect alterations in diverse aspects of P. aeruginosa biology which include lack of swimming and twitching motility, lack of production of the virulence factors such as pyocyanin, biofilm formation, and metabolic functions. In addition, Pos-STM mutants showed altered invasion and stimulation of immune response when tested in human respiratory epithelial cells, indicating that P. aeruginosa is prone to revise the interaction with its host during persistent lifestyle. Finally, sequence analysis of Pos-STM genes in longitudinally P. aeruginosa isolates from CF patients identified signs of patho-adaptive mutations within the genome. This novel Pos-STM approach identified bacterial functions that can have important clinical implications for the persistent lifestyle and disease progression of the airway chronic infection

The Bacterial Fimbrial Tip Acts as a Mechanical Force Sensor

The subunits that constitute the bacterial adhesive complex located at the tip of the fimbria form a hook-chain that acts as a rapid force-sensitive anchor at high flow

A Comparison of Shiga-Toxin 2 Bacteriophage from Classical Enterohemorrhagic Escherichia coli Serotypes and the German E. coli O104:H4 Outbreak Strain

Escherichia coli O104:H4 was associated with a severe foodborne disease outbreak originating in Germany in May 2011. More than 4000 illnesses and 50 deaths were reported. The outbreak strain was a typical enteroaggregative E. coli (EAEC) that acquired an antibiotic resistance plasmid and a Shiga-toxin 2 (Stx2)-encoding bacteriophage. Based on whole-genome phylogenies, the O104:H4 strain was most closely related to other EAEC strains; however, Stx2-bacteriophage are mobile, and do not necessarily share an evolutionary history with their bacterial host. In this study, we analyzed Stx2-bacteriophage from the E. coli O104:H4 outbreak isolates and compared them to all available Stx2-bacteriophage sequences. We also compared Stx2 production by an E. coli O104:H4 outbreak-associated isolate (ON-2011) to that of E. coli O157:H7 strains EDL933 and Sakai. Among the E. coli Stx2-phage sequences studied, that from O111:H- strain JB1-95 was most closely related phylogenetically to the Stx2-phage from the O104:H4 outbreak isolates. The phylogeny of most other Stx2-phage was largely concordant with their bacterial host genomes. Finally, O104:H4 strain ON-2011 produced less Stx2 than E. coli O157:H7 strains EDL933 and Sakai in culture; however, when mitomycin C was added, ON-2011 produced significantly more toxin than the E. coli O157:H7 strains. The Stx2-phage from the E. coli O104:H4 outbreak strain and the Stx2-phage from O111:H- strain JB1-95 likely share a common ancestor. Incongruence between the phylogenies of the Stx2-phage and their host genomes suggest the recent Stx2-phage acquisition by E. coli O104:H4. The increase in Stx2-production by ON-2011 following mitomycin C treatment may or may not be related to the high rates of hemolytic uremic syndrome associated with the German outbreak strain. Further studies are required to determine whether the elevated Stx2-production levels are due to bacteriophage or E. coli O104:H4 host related factors

Genomic variation landscape of the human gut microbiome

While large-scale efforts have rapidly advanced the understanding and practical impact of human genomic variation, the latter is largely unexplored in the human microbiome. We therefore developed a framework for metagenomic variation analysis and applied it to 252 fecal metagenomes of 207 individuals from Europe and North America. Using 7.4 billion reads aligned to 101 reference species, we detected 10.3 million single nucleotide polymorphisms (SNPs), 107,991 short indels, and 1,051 structural variants. The average ratio of non-synonymous to synonymous polymorphism rates of 0.11 was more variable between gut microbial species than across human hosts. Subjects sampled at varying time intervals exhibited individuality and temporal stability of SNP variation patterns, despite considerable composition changes of their gut microbiota. This implies that individual-specific strains are not easily replaced and that an individual might have a unique metagenomic genotype, which may be exploitable for personalized diet or drug intake

навчальний посібник

Законодавче забезпечення правоохоронної діяльності : навч. посіб. / за заг. ред. В. В. Сокуренка. – Харків : Стильна типографія, 2017. – 1164 с. – (до 100-річчя підготовки охоронців правопорядку у Харкові).У навчальному посібнику представлено методичні рекомендації, пропозиції і зауваження до проектів нормативно-правових актів та наукові роз’яснення окремих положень чинного законодавства, розроблені кафедрами факультету № 1 Харківського національного університету внутрішніх справ. Наукові праці, що включено до навчального посібника, безпосередньо стосуються питань удосконалення форм та методів діяльності слідчих і інших підрозділів органів Національної поліції України. Для працівників органів Національної поліції України, науковців, викладачів, ад’юнктів, аспірантів, докторантів, курсантів, студентів та слухачів навчальних закладів юридичного профілю, а також усіх, хто цікавиться питаннями удосконалення діяльності органів Національної поліції України і інших органів правопорядку.The training manual presents methodological recommendations, suggestions and comments on draft normative legal acts and scientific explanations of certain provisions of the current legislation developed by the departments of the faculty No. 1 of the Kharkov National University of Internal Affairs. Scientific works, included in the textbook, directly relate to issues of improving the forms and methods of activity of investigative and other units of the National Police of Ukraine. For employees of the National Police of Ukraine, scientists, teachers, adjuncts, graduate students, doctoral students, cadets, students and students of legal educational institutions, as well as anyone interested in improving the activities of the National Police of Ukraine and other law enforcement agencies.В учебном пособии представлены методические рекомендации, предложения и замечания к проектам нормативно-правовых актов и научные разъяснения отдельных положений действующего законодательства, разработанные кафедрами факультета № 1 Харьковского национального университета внутренних дел. Научные труды, включен в учебного пособия, непосредственно касаются вопросов совершенствования форм и методов деятельности следственных и других подразделений органов Национальной полиции Украины. Для работников органов Национальной полиции Украины, научных работников, преподавателей, адъюнктов, аспирантов, докторантов, курсантов, студентов и слушателей учебных заведений юридического профиля, а также всех, кто интересуется вопросами совершенствования деятельности органов Национальной полиции Украины и других органов правопорядка