General dynamics of the URT microbiome and microbial signs of recovery in COVID-19 patients.

COVID-19 is caused by an airborne virus, SARS-CoV-2. The upper respiratory tract (URT) is, therefore, the first system to endure the attack. Inhabited by an assemblage of microbial communities, a healthy URT wards off the invasion. However, once invaded, it becomes destabilised, which could be crucial to the establishment and progression of the infection. We examined 696 URT samples collected from 285 COVID-19 patients at three time-points throughout their hospital stay and 100 URT samples from 100 healthy controls. We used 16S ribosomal RNA sequencing to evaluate the abundance of various bacterial taxa, α-diversity, and ß-diversity of the URT microbiome. Ordinary least squares regression was used to establish associations between the variables, with age, sex, and antibiotics as covariates. The URT microbiome in the COVID-19 patients was distinctively different from that of healthy controls. In COVID-19 patients, the abundance of 16 genera was significantly reduced. A total of 47 genera were specific to patients, whereas only 2 were unique to controls. The URT samples collected at admission differed more from the control than from the samples collected at later stages of treatment. The following four genera originally depleted in the patients grew significantly by the end of treatment: Fusobacterium, Haemophilus, Neisseria, and Stenotrophomonas. Our findings strongly suggest that SARS-CoV-2 caused significant changes in the URT microbiome, including the emergence of numerous atypical taxa. These findings may indicate increased instability of the URT microbiome in COVID-19 patients. In the course of the treatment, the microbial composition of the URT of COVID-19 patients tended toward that of controls. These microbial changes may be interpreted as markers of recovery.

Orphan gene in Littorina: An unexpected role of symbionts in the host evolution.

Mechanisms of reproductive isolation between closely related sympatric species are of high evolutionary significance as they may function as initial drivers of speciation and protect species integrity afterwards. Proteins involved in the establishment of reproductive barriers often evolve fast and may be key players in cessation of gene flow between the incipient species. The five Atlantic Littorina (Neritrema) species represent a notable example of recent radiation. The geographic ranges of these young species largely overlap and the mechanisms of reproductive isolation are poorly understood. In this study, we performed a detailed analysis of the reproductive protein LOSP, previously identified in Littorina. We showed that this protein is evolutionary young and taxonomically restricted to the genus Littorina. It has high sequence variation both within and between Littorina species, which is compatible with its presumable role in the reproductive isolation. The strongest differences in the LOSP structure were detected between Littorina subgenera with distinctive repetitive motifs present exclusively in the Neritrema species, but not in L. littorea. Moreover, the sequence of these repetitive structural elements demonstrates a high homology with genetic elements of bacteria, identified as components of Littorina associated microbiomes. We suggest that these elements were acquired from a symbiotic bacterial donor via horizontal genetic transfer (HGT), which is indirectly confirmed by the presence of multiple transposable elements in the LOSP flanking and intronic regions. Furthermore, we hypothesize that this HGT-driven evolutionary innovation promoted LOSP function in reproductive isolation, which might be one of the factors determining the intensive cladogenesis in the Littorina (Neritrema) lineage in contrast to the anagenesis in the L. littorea clade.

Quantitative screening level assessment of human risk from PCBs released in glacial meltwater: Silvretta Glacier, Swiss Alps.

Persistent organic pollutants (POPs) are entrained within glaciers globally, reemerging in many alpine ecosystems. Despite available data on POP flux from glaciers, a study of human health risk caused by POPs released in glacial meltwater has never been attempted. Glaciers in the European Alps house the largest known quantity of POPs in the Northern Hemisphere, presenting an opportunity for identification of potential risk in an endmember scenario case study. With methodology developed by the US Environmental Protection Agency (EPA), we provide a regional screening level human risk analysis of one class of POPs, polychlorinated-biphenyls (PCB) that have been measured in melt waters from the Silvretta Glacier in the Swiss Alps. Our model suggests the potential for both cancer and non-cancer impacts in residents with lifetime exposure to current levels of PCB in glacial meltwater and average consumption of local fish. For residents with an abbreviated 30-year exposure timeframe, the risk for cancer and non-cancer impacts is low. Populations that consume higher quantities of local fish are predicted to be at a greater risk, with risk to lifetime consumers higher by an order of magnitude. Based on the results of our screening study, we suggest that local government move to the next step within the risk assessment framework: local monitoring and management. Within the Alps, other glacial watersheds of a similar size and latitude may see comparable risk and our model framework can be adapted for further implementation therein.

Legacy organochlorine pollutants in glacial watersheds: a review.

Northern Hemisphere alpine glaciers have been identified as a point of concentration and reemergence of legacy organochlorine pollutants (OCPs). In this review, we compile a selection of published literature combining long-range, global atmospheric transport and distribution-based compartmental environmental flux models, as well as data from glacial meltwater, ice core, crevasse and proglacial lake sediment studies. Regional studies of ice and meltwater in alpine glaciers of the northern latitudes show similarities in sample deposition profiles and concentration due to chemical atmospheric residence time, precipitation type and glacier flow rates. In glaciated locations near areas of extensive OCPs use, such as the Swiss and Italian Alps, glacier sample concentrations are higher, while in areas more distant from use, including Arctic nations, OCPs concentrations in glaciers are significantly lower. Our review identifies alpine glaciers co-located with regions characterized by OCPs use as a significant organochlorine pollutant distribution source, secondary in timing and location to direct deposition, with subsequent bioaccumulation and potential human risk impacts.

Release of PCBs from Silvretta glacier (Switzerland) investigated in lake sediments and meltwater.

This study is part of our investigations about the release of persistent organic pollutants from melting Alpine glaciers and the relevance of the glaciers as secondary sources of legacy pollutants. Here, we studied the melt-related release of polychlorinated biphenyls (PCBs) in proglacial lakes and glacier streams of the catchment of the Silvretta glacier, located in the Swiss Alps. To explore a spatial and temporal distribution of chemicals in glacier melt, we combined two approaches: (1) analysing a sediment record as an archive of past remobilization and (2) passive water sampling to capture the current release of PCBs during melt period. In addition, we determined PCBs in a non-glacier-fed stream as a reference for the background pollutant level in the area. The PCBs in the sediment core from the Silvretta lake generally complied with trends of PCB emissions into the environment. Elevated concentrations during the most recent ten years, comparable in level with times of the highest atmospheric input, were attributed to accelerated melting of the glacier. This interpretation is supported by the detected PCB fractionation pattern towards heavier, less volatile congeners, and by increased activity concentrations of the radioactive tracer (137)Cs in this part of the sediment core. In contrast, PCB concentrations were not elevated in the stream water, since no significant difference between pollutant concentrations in the glacier-fed and the non-glacier-fed streams was detected. In stream water, no current decrease of the PCBs with distance from the glacier was observed. Thus, according to our data, an influence of PCBs release due to accelerated glacier melt was only detected in the proglacial lake, but not in the other compartments of the Silvretta catchment.

Application of HSV colour system in identification by colour of biological objects on the basis of microscopic images.

This paper demonstrates preliminary image processing with the aim of obtaining invariant signs for identification by colour. For this purpose we have used microscopic images of cell structures in coloured peripheral blood smears. The main parameter for the identification is the colouring of the respective cell structures on the basis of which we have created histograms by hue for the available cell types.

[Hygienic aspects of youth work brigades]. / Khigienni aspekti na mladezhkite trudovi brigadi.

A comprehensive inquiry study was carried out on living conditions, labour and regime in youth brigades. Furthermore, a complex hygienic-physiological assessment was made of the work of the students gone on agricultural brigades on the base of studies on the changes in the cardiovascular system, energy expenditure, nervous-muscular and thermoregulatory apparatuses, as well as on the functional activity of sympathico-adrenal system. The work, done by the students-members of the brigades, is qualified as moderately heavy, and as heavy only in some labour operations. Regardless of the relatively heavy and intensive work, the students are not overtired, because the duration of the working time is shortened on account of the rests, made at their desire. Recommendations are presented for the improvement both of the conditions in brigade camps and organization of labour regime.

[Age-related characteristics of reactivity of school children during mental processes]. / Vuzrastovi osobenosti na reaktivnostta na uchenitsite pri umstveno natovarvane.

An examination of 300 students was carried out, aged 9, 12 and 15, in the process of their training, aiming at the establishment of the characteristics of their reactivity to mental loading. Modern psychophysiological and biochemical methods were used in the dynamic follow up of the changes in CNS and neuroendocrine activity. Definite age and sex discrepancies were found, on the base of the analysis, in the CNS reactivity to mental loading. With the growing up, the volume and speed of the work performed were increased and their accuracy enhanced. The boys showed faster reactions and less accuracy at work. The girls were distinguished with a better characteristic of their capacity for work. The curves of the daily and weekly dynamics of mental capacity for work were outlined.

[Health status and morbidity in schoolchildren from villages in Silistra and Tutrakan Districts]. / Prouchvane na zdravnoto sustoianie i zabolevaemostta na uchenitsi ot niakoi sela na Silistrenski i Tutrakanski raion.

This is study of the health state and morbidity rate in a group comprising 408 schoolchildren from the Silistra and Tutrakan regions, aged 7 to 14 years. The results of the research demonstrate a slight lagging behind of the school-children's physical development relative to children of comparable ages from the urban areas. Their health state is estimated as good, and the somatic neurotic morbidity--rather low. The most frequently encountered affections include diseases of the upper airways, infectious and dental diseases. A considerable number of slightly hypochromic anemias are also recorded.

[Free plasma cortisol in mothers and newborn infants immediately after birth]. / Le cortisol plasmatique libre de la mère et du nouveau-né aussitôt après la naissance.

Free plasma cortisol levels were determined in 60 mothers and their newborn infants by the method of Ousvatova and Pankov. Twenty healthy, nonpregnant women were used as a control group. The data showed that the level of free plasma cortisol was higher in the mothers than in the healthy, nonpregnant women. The free plasma cortisol level in the newborn infants was lower than in the mothers but higher than in the non-pregnant women.