Vibrio cholerae secretion system of the type VI

The review summarizes literature data on the Vibrio cholerae secretion system of the 6th type. This system is a contact-dependent macromolecular mechanism through which bacteria translocate toxic effector proteins into target cells. It is found in many Gram-negative bacteria, including Vibrio cholerae. V. cholerae infects phagocytic amoebae, nematodes, ciliates, bacteria belonging to different species, as well as unrelated strains of V. cholerae using this system. DNA released after lysis of competing bacteria can be taken up by Vibrio cholerae cells, which leads to the acquisition of new genetic material. The type VI secretion system is involved in the infectious process. The destruction of macrophages and microbiota contributes to the active reproduction of the pathogen and colonization of host epitheliocytes, and the production of effector proteins causes the development of diarrhea and intestinal inflammation. Cholera vibrio secretion system of the 6th type has a structure similar to other gram-negative bacteria. The genes encoding the proteins of this system are located in one large region of the second chromosome and in several additional clusters. It has been shown that toxigenic strains of V. cholerae contain an identical set of secretion system genes, while their composition is variable in non-toxigenic isolates. The regulation of secretion system protein expression differs in V. cholerae strains of different toxigenicity, depends on a number of environmental signals, and is associated with other cell regulatory networks. The paper provides experimental data on the analysis of the structure of the global regulatory gene, vasH, of the type VI secretion system in toxigenic and non-toxigenic V. cholerae O1, biovar El Tor strains isolated in the Russian Federation. Thus, the type VI secretion system is an important mechanism that facilitates the survival of V. cholerae in complex communities in vitro, protects against damaging factors of the macroorganism and increases virulence in vivo, and also provides evolutionary transformations of cholera vibrio. Further study of this system will allow a better understanding of the pathogen-host interaction processes, as well as the adaptation mechanisms of V. cholerae in the external environment

Comparative Analysis of Survival Capacity among Typical and Genovariant Strains of <i>Vibrio cholerae</i>, Biovar El Tor <i>in vivo</i> and <i>in vitro</i>

Objective of the study was to conduct experiments on survival capacity of toxigenic genovariant strains as compared to typical strains of V. cholerae , biovar El Tor in autoclaved river water and in the organism of laboratory animals. Consequently, it was determined that both, genovariant and typical El Tor vibrios, sustained for a significant period of time (more than 5 months) in the river water, though a number of the bacterial cells in the population of the typical ones gradually decreased, while in the genovariant strains - the growth was observed in between the 7th and 21st day. CFU of the genovariants was 1.5-2.5 and 1.8-3.0 times higher than the amount of typical strain bacteria on the day 7 and day 21, respectively. Selective advantage of genovariants was also confirmed by competitive test in vitro . Furthermore, genovariants dominated over typical strains of V. cholerae , biovar El Tor in the mixed population in vivo (bioassay animals): CFU of the genovariants 1.25-84.0 times exceeded that of the typical strains when seeding out the contents of intestine and gastrointestinal wall homogenate. Put forward was an assumption that one of the factors for genovariant selective advantage might be enhanced adaptation ability affected by changes of cell metabolic activity. Identified capacity of genovariant toxigenic strains - not only to sustain in open water bodies of our country, but also to propagate in there, creates unfavorable epidemiological situation on cholera

Gyrodactylus salinae n. sp. (Platyhelminthes: Monogenea) infecting the south European toothcarp Aphanius fasciatus (Valenciennes) (Teleostei, Cyprinodontidae) from a hypersaline environment in Italy

Background: Historically, non-native species of Gambusia (Poeciliidae) have been used to control larval stages of the Asian tiger mosquito, Stegomyia albopicta Reinert, Harbach et Kitching, 2004 throughout Italy. The potential utility of indigenous populations of Aphanius fasciatus (Valenciennes) (Teleostei: Cyprinodontidae) as an appropriate alternative biological control is currently being explored. A sub-sample of ten fish collected from Cervia Saline, Italy (salinity 65 ppt; 30&deg;C) to assess their reproductive capability in captivity, harboured a moderate infection of Gyrodactylus von Nordmann, 1832 (Platyhelminthes, Monogenea). A subsequent morphological and molecular study identified this as being a new species. Results: Gyrodactylus salinae n. sp. is described from the skin, fins and gills of A. fasciatus. Light and scanning electron microscopical (SEM) examination of the opisthaptoral armature and their comparison with all other recorded species suggested morphological similarities to Gyrodactylus rugiensoides Huyse et Volckaert, 2002 from Pomatoschistus minutus (Pallas). Features of the ventral bar, however, permit its discrimination from G. rugiensoides. Sequencing of the nuclear ribosomal DNA internal transcribed spacers 1 and 2 and the 5.8S rRNA gene and a comparison with all species listed in GenBank confirmed they are unique and represent a new species (most similar to Gyrodactylus anguillae Ergens, 1960, 8.3% pair-wise distance based on 5.8S+ITS2). This represents the first species of Gyrodactylus to be described from Aphanius and, to date, has the longest ITS1 (774 bp) sequenced from any Gyrodactylus. Additional sampling of Cervia Saline throughout the year, found G. salinae n. sp. to persist in conditions ranging from 35 ppt and 5&deg;C in December to 65 ppt and 30&deg;C in July, while in captivity a low level of infection was present, even in freshwater conditions (0 ppt). Conclusions: The ability of G. salinae n. sp. to tolerate a wide range of salinities and temperatures shows its potential to readily adapt to several environmental conditions. These findings, together with the fact that A. fasciatus is a protected species and is considered as a biological control organism, necessitate further studies on the ecology and virulence of G. salinae n. sp

Light regulation of metabolic pathways in fungi

Light represents a major carrier of information in nature. The molecular machineries translating its electromagnetic energy (photons) into the chemical language of cells transmit vital signals for adjustment of virtually every living organism to its habitat. Fungi react to illumination in various ways, and we found that they initiate considerable adaptations in their metabolic pathways upon growth in light or after perception of a light pulse. Alterations in response to light have predominantly been observed in carotenoid metabolism, polysaccharide and carbohydrate metabolism, fatty acid metabolism, nucleotide and nucleoside metabolism, and in regulation of production of secondary metabolites. Transcription of genes is initiated within minutes, abundance and activity of metabolic enzymes are adjusted, and subsequently, levels of metabolites are altered to cope with the harmful effects of light or to prepare for reproduction, which is dependent on light in many cases. This review aims to give an overview on metabolic pathways impacted by light and to illustrate the physiological significance of light for fungi. We provide a basis for assessment whether a given metabolic pathway might be subject to regulation by light and how these properties can be exploited for improvement of biotechnological processes

The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance

INTRODUCTION Investment in Africa over the past year with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing has led to a massive increase in the number of sequences, which, to date, exceeds 100,000 sequences generated to track the pandemic on the continent. These sequences have profoundly affected how public health officials in Africa have navigated the COVID-19 pandemic. RATIONALE We demonstrate how the first 100,000 SARS-CoV-2 sequences from Africa have helped monitor the epidemic on the continent, how genomic surveillance expanded over the course of the pandemic, and how we adapted our sequencing methods to deal with an evolving virus. Finally, we also examine how viral lineages have spread across the continent in a phylogeographic framework to gain insights into the underlying temporal and spatial transmission dynamics for several variants of concern (VOCs). RESULTS Our results indicate that the number of countries in Africa that can sequence the virus within their own borders is growing and that this is coupled with a shorter turnaround time from the time of sampling to sequence submission. Ongoing evolution necessitated the continual updating of primer sets, and, as a result, eight primer sets were designed in tandem with viral evolution and used to ensure effective sequencing of the virus. The pandemic unfolded through multiple waves of infection that were each driven by distinct genetic lineages, with B.1-like ancestral strains associated with the first pandemic wave of infections in 2020. Successive waves on the continent were fueled by different VOCs, with Alpha and Beta cocirculating in distinct spatial patterns during the second wave and Delta and Omicron affecting the whole continent during the third and fourth waves, respectively. Phylogeographic reconstruction points toward distinct differences in viral importation and exportation patterns associated with the Alpha, Beta, Delta, and Omicron variants and subvariants, when considering both Africa versus the rest of the world and viral dissemination within the continent. Our epidemiological and phylogenetic inferences therefore underscore the heterogeneous nature of the pandemic on the continent and highlight key insights and challenges, for instance, recognizing the limitations of low testing proportions. We also highlight the early warning capacity that genomic surveillance in Africa has had for the rest of the world with the detection of new lineages and variants, the most recent being the characterization of various Omicron subvariants. CONCLUSION Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve. This is important not only to help combat SARS-CoV-2 on the continent but also because it can be used as a platform to help address the many emerging and reemerging infectious disease threats in Africa. In particular, capacity building for local sequencing within countries or within the continent should be prioritized because this is generally associated with shorter turnaround times, providing the most benefit to local public health authorities tasked with pandemic response and mitigation and allowing for the fastest reaction to localized outbreaks. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century

Вміст вітаміну D у чоловіків з гіпотиреозом та його кореляція з рівнем тестостерону

Background. Recent studies have found a correlation between vitamin D deficiency and the state of thyroid autoimmunity. However, it remains unclear whether low levels of 25(OH)D are a consequence of hypothyroidism or a cause. The aim is to investigate the content of vitamin D in the serum and to establish its correlation with testosterone levels in men with hypothyroidism. Materials and methods. During the autumn months of 2019, 52 men with hypothyroidism were examined in the endocrinology department of Ternopil University Hospital. The median age of the subjects was 56.0 years (51.0—64.0). Depending on the level of testosterone in the serum (up to 8.0 nmol/l and more than 12 nmol/l), patients were divided into two groups: with androgen deficiency (n = 21) and with normal testosterone (n = 31). The results of assessment of 20 healthy men with a median age of 49.0 years (46.0—52.0)served as control. Results and discussion. An inverse correlation was established between the level of vitamin D and the level of TSH in the blood (r = -0.26; p < 0.05), BMI (r = -0.32; p < 0.01) andserum leptin = -0.37; p < 0.05). A direct correlation was demonstrated between total testosterone and vitamin D (r = 0.16; p < 0.05), TSH and leptin levels (r = 0.28; p < 0.05), TSHand with HOMA-IR index (r = 0.34; p < 0.05), leptin and fasting glycemia (r = 0.34; p < 0.05) and HOMA index (r = 0.36; p < 0.05). Logistic regression was used to show a relationship between 25 (OH) D levels and total testosterone. Compared with men in the highest quartile of 25(OH)Dlevel, the probabilityof androgen deficiency in men in the lowest quartile of 25(OH)D was 1.52 (95 % CI, 1.18, 2.03; P < 0.05). The level of 25(OH)D is positively associated with the level of total testosterone. Conclusions. In men with hypothyroidism, vitamin D deficiency was found both on the background of androgen deficiency (13.9 ± 1.7 ng/ml) and with normal total testosterone (19.6 ± 1.8 ng/ml). Theserum level of 25(OH)D is positively associated with serum total testosterone.Цель работы — исследовать содержание витамина D (25(OH)D) в сыворотке крови и установить взаимосвязь между ним и уровнем тестостерона у мужчин, больных гипотиреозом. Материалы и методы. В эндокринологичес­­ком отделении Тернопольской университетской больницы в течение сентября—ноября 2019 г. обследованы 52 мужчины с гипотиреозом. Медиана возраста обследованных составила 56,0 лет (51,0–64,0). В зависимости от уровня тестостерона в сыворотке крови ( 12 нмоль/л) больных разделили на две группы: с андрогенным дефицитом (n = 21) и нормальным содержанием тестостерона (n = 31). Контролем служили результаты обследования 20 практически здоровых мужчин, медиана возраста которых составила 49,0 лет (46,0—52,0). Результаты и обсуждение. Выявлена обратно пропорциональная связь между уровнями витамина D и тиреотропного гормона (ТТГ) в крови (r = –0,26; р < 0,05), индексом массы тела (r = –0,32; р Мета роботи — дослідити вміст вітаміну D (25(OH)D) у сироватці крові та встановити взаємозв’язок між ним і рівнем тестостерону у чоловіків, хворих на гіпотиреоз. Матеріали та методи. В ендокринологічному відділенні Тернопільської університетської лікарні впродовж вересня—листопада 2019 р. обстежено 52 чоловіків з гіпотиреозом. Медіана віку обстежених становила 56,0 років (51,0—64,0). Залежно від рівня тесто­­стерону в сироватці крові ( 12 нмоль/л) хворих розподілили на дві групи: з андрогенним дефіцитом (n = 21) та нормальним вмістом тестостерону (n = 31). Контролем слугували результати обстеження 20 практично здорових чоловіків, медіана віку яких становила 49,0 років (46,0—52,0). Результати та обговорення. Виявлено обернено пропорційний зв’язок між рівнями вітаміну D і тиреотропного гормону (ТТГ) у крові (r= –0,26; р

Comparative Analysis of Molecular-Genetic Properties in Non-Toxigenic Vibrio cholerae O1 Strains Biovar El Tor, Isolated in Russia and on Cholera Endemic Territories

Objective of the study was to perform a comparative analysis of molecular-genetic properties in non-toxigenic Vibrio cholerae O1 strains biovar El Tor, isolated in the Republic of Kalmykia and on cholera endemic territories and to reveal their phylogenetic relations to toxigenic isolates.Materials and methods. We have carried out bio-information analysis of whole genome sequences of 60 cholera vibrio strains from endemic as regards cholera regions and from Kalmykia. The presence of pathogenicity and endemicity islands in their genomes has been determined. Specifed have been the sequence-types of the examined strains and whole genome SNP-analysis conducted.Results and discussion. Non-toxigenic El Tor vibrios circulating in Kalmykia are clustered into two major genotypes: ctxA–tcpA+VPI-2+VSP– and ctxA–tcpA–VPI-2Δ+VSP–, where VPI-2 Δ+ signifes the presence of deletions of varying length in the genome of this pathogenicity island. Only the latter one is found in regions endemic for cholera. In addition, ctxA– tcpA+VPI-2+VSP+ populations circulate in cholera endemic foci, not found in Kalmykia. 17 sequence-types were identifed among the studied strains (by seven housekeeping gene loci). Phylogenetic analysis performed using SNP-typing demonstrated the absence of close genetic relation between the ctxA–tcpA+VPI-2+VSP– vibrios from Kalmykia and both toxigenic and non-toxigenic vibrios with different composition of pathogenicity and pandemicity islands in the genome. At the same time, genetic proximity of ctxA–tcpA–VPI-2Δ+VSP– cholera vibrios from endemic cholera foci with those isolated in Kalmykia was detected, which may indicate the possibility of their recurrent importation into the territory of Russia. Non-toxigenic V. cholerae strains found in the territory of Kalmykia are characterized by a high genetic diversity. Circulation of the strains with unique sequence-types suggests their potential for long-term persistence on this territory. At the same time, phylogenetic closeness and identity of certain strains with strains from endemic territories can be an evidence of repeated importation