The microbial ecology of Candida albicans strains CHN1 and SC5314 in mice

Strain SC5314 is the most widely studied strain of Candida albicans. Despite C. albicans being the most commonly isolated yeast from the human gastrointestinal (GI) microbiome, strain SC5314 does not stably colonize the mouse GI tract long term, even after antibiotic disruption. In contrast, strain CHN1 will stably colonize the mouse GI tract long term. Comparative genomic analysis of strain CHN1 indicates that it belongs to a different evolutionary clade of C. albicans than strain SC5314. Previous studies from our laboratory have shown that colonization by strain CHN1 causes a change in the GI bacterial microbiome of mice and predisposes them to more robust Th2 immune responses. Despite this, little is known about the GI microbial ecology of SC5314 vs. CHN1 and subsequent host responses. Using a short-term antibiotic disruption model in C57BL/6 mice, we have been able to observe significantly different colonization kinetics between these two C. albicans strains, with CHN1 establishing stable long-term colonization. In contrast, colonization by SC5314 was lower, highly variable and cage-dependent. C. albicans colonization kinetics impacted the composition of the bacterial microbiome with a marked effect on the levels of Lactobacillus and Enterococcus. qPCR analysis of 46 host immune response genes did not detect significant differences in host gene expression between SC5134 and CHN1 colonized mice, except for chitinase expression. Thus, these studies suggest that yeast-bacteria interactions in the microbiome may be far more important in determining long-term colonization potential of C. albicans and secondary immunomodulatory effects.

Cell colonization potential of thermoplastic silicone-based polyurethane nonwovens for novel heart valve prosthesis

Heart valve tissue engineering aims at creating living valves through colonization of scaffolds with patient’s own cells. Various cell sources have been explored focusing mainly on endothelialization of the scaffold surface. Endothelial like cells, such as endothelial progenitor cells (EPCs), which can be isolated from peripheral blood or bone marrow could be a suitable option. In this study we investigated cell colonization potential of ovine EPCs (OEPCs) on thermoplastic silicone-based polyurethane (TSPU) polymer scaffolds. TSPU nonwovens with and without vascular endothelial growth factor (VEGF) functionalization were used. SEM images showed that by day 3 the cells were growing as patches on the surface of both polymer groups. The cell patches continued growing and started covering more of the nonwoven surface. On day 7 the cells had almost covered the scaffold surface. The cells were more uniformly distributed as monolayer on the functionalized TSPU compared to the non-functionalized nonwovens. Live/Dead staining provided bright green fluorescence on the samples, indicating metabolically active alive cells. These static cell seeding experiments demonstrated that functionalized TPSU nonwovens support endothelialization. The feasibility of TPSU nonwovens as heart valve prosthesis scaffold could be further explored with animal studies in an ovine model.

Gammaproteobacteria, a core taxon in the guts of soil fauna, are potential responders to environmental concentrations of soil pollutants

Background The ubiquitous gut microbiotas acquired from the environment contribute to host health. The gut microbiotas of soil invertebrates are gradually assembled from the microecological region of the soil ecosystem which they inhabit, but little is known about their characteristics when the hosts are under environmental stress. The rapid development of high-throughput DNA sequencing in the last decade has provided unprecedented insights and opportunities to characterize the gut microbiotas of soil invertebrates. Here, we characterized the core, transient, and rare bacterial taxa in the guts of soil invertebrates using the core index (CI) and developed a new theory of global microbial diversity of soil ecological microregions. Results We found that the Gammaproteobacteria could respond indiscriminately to the exposure to environmental concentrations of soil pollutants and were closely associated with the physiology and function of the host. Meanwhile, machine-learning models based on metadata calculated that Gammaproteobacteria were the core bacteria with the highest colonization potential in the gut, and further identified that they were the best indicator taxon of the response to environmental concentrations of soil pollution. Gammaproteobacteria also closely correlated with the abundance of antibiotic resistance genes. Conclusions Our results determined that Gammaproteobacteria were an indicator taxon in the guts of the soil invertebrates that responded to environmental concentrations of soil pollutants, thus providing an effective theoretical basis for subsequent assessments of soil ecological risk. The results of the physiological and biochemical analyses of the host and the microbial-community functions, and the antibiotic resistance of Gammaproteobacteria, provide new insights for evaluating global soil ecological health.

Multiple evolutionary origins reflect the importance of sialic acid transporters in the colonization potential of bacterial pathogens and commensals

Located at the tip of cell surface glycoconjugates, sialic acids are at the forefront of host–microbe interactions and, being easily liberated by sialidase enzymes, are used as metabolites by numerous bacteria, particularly by pathogens and commensals living on or near diverse mucosal surfaces. These bacteria rely on specific transporters for the acquisition of host-derived sialic acids. Here, we present the first comprehensive genomic and phylogenetic analysis of bacterial sialic acid transporters, leading to the identification of multiple new families and subfamilies. Our phylogenetic analysis suggests that sialic acid-specific transport has evolved independently at least eight times during the evolution of bacteria, from within four of the major families/superfamilies of bacterial transporters, and we propose a robust classification scheme to bring together a myriad of different nomenclatures that exist to date. The new transporters discovered occur in diverse bacteria, including Spirochaetes , Bacteroidetes , Planctomycetes and Verrucomicrobia , many of which are species that have not been previously recognized to have sialometabolic capacities. Two subfamilies of transporters stand out in being fused to the sialic acid mutarotase enzyme, NanM, and these transporter fusions are enriched in bacteria present in gut microbial communities. Our analysis supports the increasing experimental evidence that competition for host-derived sialic acid is a key phenotype for successful colonization of complex mucosal microbiomes, such that a strong evolutionary selection has occurred for the emergence of sialic acid specificity within existing transporter architectures.

Shaping of the Present-Day Deep Biosphere at Chicxulub by the Impact Catastrophe That Ended the Cretaceous

We report on the effect of the end-Cretaceous impact event on the present-day deep microbial biosphere at the impact site. IODP-ICDP Expedition 364 drilled into the peak ring of the Chicxulub crater, México, allowing us to investigate the microbial communities within this structure. Increased cell biomass was found in the impact suevite, which was deposited within the first few hours of the Cenozoic, demonstrating that the impact produced a new lithological horizon that caused a long-term improvement in deep subsurface colonization potential. In the biologically impoverished granitic rocks, we observed increased cell abundances at impact-induced geological interfaces, that can be attributed to the nutritionally diverse substrates and/or elevated fluid flow. 16S rRNA gene amplicon sequencing revealed taxonomically distinct microbial communities in each crater lithology. These observations show that the impact caused geological deformation that continues to shape the deep subsurface biosphere at Chicxulub in the present day.

Organotin compounds as effective antimetastatic substances in the treatment of epidermoid lung carcinoma Lewis (LLC) in an experiment.

e15054 Background: Lung cancer occupies one of the first places in the structure of oncological diseases in the world. Reducing the life expectancy of patients, as a rule, occurs as a result of metastatic complications, so the search for new antimetastatic agents is an urgent task for experimental pharmacology and oncology. The aim of our study is to assess the severity of metastatic lesion in the Lewis lung epidermoid carcinoma (LLC) model in the presence of an organotin compound. Methods: The study was conducted on experimental C57BL/6 mice (n = 24, each group contained 12 mice) with LLC (subcutaneous transplantation) in the presence of the cytotoxic organotin compound 2,6-bis (1,1-dimethylethyl) - 4 - [(triphenylstannyl)thio]phenol (Me5). All manipulations were carried out in accordance with the European Convention for the Protection of Vertebrates Used for Experimental and Other Scientific Purposes (ETS 123). Female mice (8 weeks of age, weighing 21-22 g) were intraperitoneally injected with a 1% aqueous gelatin solution of organotin Me5 daily for 5 days. The most effective total dose of Me5 was 250 mg / kg. The animals of the control group received saline solution in similar modes and volumes. In the experimental and control groups, the degree of metastatic lesion was assessed on the 21-day post-grafting period according to the scale proposed by D. Tarin and J. E. Price, which allows us to differentiate the severity of the lesion depending on the number of metastases and their size. The experiment describes three degrees of lesion: LCP-1 (metastases less than 10 pcs. with a diameter not exceeding 1 mm); LCP-2 (metastases from 10 to 30 pieces, some of them larger than 1 mm) and HCP-3 (metastases larger than 30 pieces of different sizes, but no drain). The pathohistological structure was studied by the light-optical method with hematoxylin and eosin staining. Results: When administered intraperitoneal to mice, Me5 did not inhibit the growth of the primary tumor site in the experimental group, but significantly reduced the severity of metastatic lesions in the lungs. In the control group, 75 % of mice with LLC had LCP - 2 (low colonization potential) and in 25% of HCP-3 (high colonization potential) metastatic lesions, in the experimental group only mild lesions were noted in all animals: 58% of mice had LCP – 1, 42% - LCP-2. Conclusions: It is concluded that the overall result of this study clearly demonstrates that the organotin compound 2,6-bis (1,1-dimethylethyl) - 4 - [(triphenylstannyl)thio] phenol (Me5) is an effective antimetastatic agent in the Lewis lung epidermoid carcinoma (LLC) model at a total dose of 250 mg/kg.

The mobile genetic element RD2 affects colonization potential of different GAS serotypes

M-type 28 Streptococcus pyogenes (Group A Strep, GAS) strains are highly associated with life-threatening puerperal infections. Genome sequencing has revealed a large mobile genetic element, RD2, present in most M28 GAS isolates but not found widely in other serotypes. Previous studies have linked RD2 to the ability of M28 GAS to colonize the vaginal tract. A new study by Roshika and colleagues use gain-of-function mutants in three different GAS serotypes to help determine why RD2 appears to have a serotype preference and what that could mean for GAS mucosal colonization and pathogenesis.

“New” Cossack Troops in Government Projects and Official Notes of the 1860s

Introduction. The article considers the government policy for the Cossacks in the 1860s. During this period, the processes of organization/reorganization of the Cossack troops were most brightly shown. These processes were developed against the background of discussions between imperial officials about the roles and values of the Cossacks from the point of view of his military and colonization potential. Only the Semirechensky (Almaty) army created in 1867 was a “new” Cossack army for the empire. Methods and materials. As the main material for writing the article the contemporary records found in the 330th fund of the Russian state military and historical archive (Moscow) and the Historical archive of Omsk region (Omsk) served. The note of the chief of Tersky region in 1863–1875 M.T. Loris-Melikov “About education of the Transcaucasian Cossack army”, prepared in December, 1868, is of particular importance. The specifics of the sources attracted required the use of methods of source studies in accordance with the type of documents under consideration, followed by the structural analysis of the identified data based on the systematic approach. Discussion. The announced subject is poorly developed in historical literature, and only the studying of Semirechensky Cossack army history has a long tradition. Separately, the question of the place of the Cossacks in the projects for the administrative structure of the Central Asian possessions of the empire and plans for the training of new troops, except for Semirechensk, has not yet been considered in historiography. Analysis. At the initiative of the governor general of Western Siberia A.P. Khrushchov in 1867–1868, projects on the organizations of the Irtysh, Akmola, Semipalatinsk Cossack troops, as well as plans for the resettlement of the Cossacks to the lands bordering Western China, were prepared. Despite the support of the initiatives of A.P. Khrushchov from the Minister of War D.A. Milyutin and the Steppe commission, the projected Cossack troops nevertheless were not created, and the Cossack colonization of border territories did not take place. The negative decision of the authorities was also made on the note of the chief of Tersky region M.T. Loris-Melikov “About education of the Transcaucasian Cossack army” (1868). Conclusions. The article examines the reasons why colonization plans and projects for the creation of new Cossack troops were unclaimed in the 1860s.