Variability of pathogenicity factors representative of the human microbiome under the influence of γ-Fe2O3 nanoparticles

Biomedical applications of nanoparticles require deep understanding of their interaction with normal human microflora. Previously, the toxic and mutagenic properties of iron oxide nanoparticles as well as their effect on the growth and morphology of the microflora were extensively investigated. However, the studies related to the variability of microbial pathogenicity factors induced by iron oxide nanoparticles are very limited. Meanwhile, this characteristic of microbes is genetically determined and is important for their survival and distribution in the human body. Therefore, pathogenicity factors are significant indicators of the experimental studies. In this work, the effect of the presence of Fe2O3 nanoparticles obtained by laser target evaporation (LTE) on selected enzymes that demonstrate invasion and aggression factors was evaluated for three reference strains of Candida albicans, Staphylococcus aureus, and Escherichia coli. It was found that the presence of LTE Fe2O3 nanoparticles supplied in the form of water-based suspensions does not induce changes of the above-mentioned parameters

The Complete Genome Sequence of Yersinia pseudotuberculosis IP31758, the Causative Agent of Far East Scarlet-Like Fever

The first reported Far East scarlet-like fever (FESLF) epidemic swept the Pacific coastal region of Russia in the late 1950s. Symptoms of the severe infection included erythematous skin rash and desquamation, exanthema, hyperhemic tongue, and a toxic shock syndrome. The term FESLF was coined for the infection because it shares clinical presentations with scarlet fever caused by group A streptococci. The causative agent was later identified as Yersinia pseudotuberculosis, although the range of morbidities was vastly different from classical pseudotuberculosis symptoms. To understand the origin and emergence of the peculiar clinical features of FESLF, we have sequenced the genome of the FESLF-causing strain Y. pseudotuberculosis IP31758 and compared it with that of another Y. pseudotuberculosis strain, IP32953, which causes classical gastrointestinal symptoms. The unique gene pool of Y pseudotuberculosis IP31758 accounts for more than 260 strain-specific genes and introduces individual physiological capabilities and virulence determinants, with a significant proportion horizontally acquired that likely originated from Enterobacteriaceae and other soil-dwelling bacteria that persist in the same ecological niche. The mobile genome pool includes two novel plasmids phylogenetically unrelated to all currently reported Yersinia plasmids. An icm/dot type IVB secretion system, shared only with the intracellular persisting pathogens of the order Legionellales, was found on the larger plasmid and could contribute to scarlatinoid fever symptoms in patients due to the introduction of immunomodulatory and immunosuppressive capabilities. We determined the common and unique traits resulting from genome evolution and speciation within the genus Yersinia and drew a more accurate species border between Y. pseudotuberculosis and Y. pestis. In contrast to the lack of genetic diversity observed in the evolutionary young descending Y. pestis lineage, the population genetics of Y. pseudotuberculosis is more heterogenous. Both Y. pseudotuberculosis strains IP31758 and the previously sequenced Y. pseudotuberculosis strain IP32953 have evolved by the acquisition of specific plasmids and by the horizontal acquisition and incorporation of different genetic information into the chromosome, which all together or independently seems to potentially impact the phenotypic adaptation of these two strains

Diversity of CRISPR loci in <i>Yersinia pseudotuberculosis</i> strains and their association with pathogenicity factors

Introduction. Heterogeneous microbial populations exist in the nature due to exchange of genetic material containing in extrachromosomal and transposable elements. Structures controlling horizontal gene transfer may affect development of pathogen genetic variants. The aim of the study is to analyze molecular genetic characteristics of CRISPR-loci in Yersinia pseudotuberculosis strains circulating in Russia and their association with pathogenicity factors. Materials and methods. We studied 56 strains of Y. pseudotuberculosis isolated from different sources in Russia during 19352014 from various sources in different regions of Russian Federation and in other countries. DNA fragments with CRISPR-loci were isolated and amplified by PCR, and subjected to Sanger sequencing. PCR was used to determine chromosomal genes of superantigen ypmA/C, pathogenicity islands HPI, YAPI, and plasmids pYV and pVM82. Results. Analysis of CRISPR-loci in Y. pseudotuberculosis showed that spacer content varies in strains depending on serotype, set of pathogenicity factors, and isolation place. The most variable loci are YP1 and YP3, locus YP2 is homogeneous. Locus YP1 varies in strains that differ by presence of plasmid pVM82, while content of locus YP3 depends on presence of plasmid pVM82 and adhesion pathogenicity island YAPI. Conclusion. Strains of Y. pseudotuberculosis circulating in Russia have a huge diversity of pathogenicity factors and CRISPR spacer content. Most of Russian strains differ by molecular markers from strains isolated in other countries. High variability is defined by ability to get new genetic elements in horizontal gene transfer. In bacteria, CRISPR-Cas system provides immunity against mobile genetic elements and can participate in formation of Y. pseudotuberculosis pathogenic potential

Heterogeneity of population of microorganisms grown in presence of iron oxide maghemite nanoparticles

In this work γ-Fe2O3 MNPs were obtained by laser target evaporation and water based suspensions were prepared. Maximum permissive dose of iron in water (MPD) is 0.3 mg/L. It was found that 100 MPD dose of iron induces formation of non-typical colonies after 72 or 96 hours exposition: against a background of small black colonies large white colonies appeared due to a disruption in tyrosine synthesis. Multiple re-cloning of the white colonies grown with MNPs showed that they retained their properties both under standard conditions (temperature of 24 °C) and at the temperatures up to 37o C. E.nigrum grown with MNPs demonstrated very scant extension of small colonies at the cultivation temperature of 24o C, their growth was completely blocked at 37°C. Significant changes in the structure of the population were noted. First of all, large cells with pronounced aggregation were observed among the black colonies. These aggregates consisted of large cells connected to each other by matrix. In the white colonies the appearance of very long threadlike cells connecting different groups of the cells establishing an intercellular communication was evident. Fe2O3 MNPs induce an increase in the heterogeneity of the population, expressed as a change in morpho-physiological states