Influence of factors of electroplating production on the immunoreactivity of the body of workers

Introduction. Modern electroplating production is the leader in air pollution of the working area with substances containing highly toxic compounds. Therefore, early detection of the negative impact of harmful factors on the body of workers is of paramount importance. The purpose of the study: to evaluate changes in individual parts of the immune system under prolonged exposure to chemical factors of the production environment. Materials and methods. 195 employees of electroplating production (the leading group) and 67 employees who are not in contact with harmful factors of the production environment (the control group) were examined. Cytochemical and immunological studies were performed according to standard and unified methods. The nickel content in the urine was determined by the voltammetric method. Results. With an increase in the work experience of workers, there is a decrease in the activity of myeloperoxidase of neutrophils MPn (r = -0.89) and an increase in the activity of acid phosphatase of neutrophils AcPN, alkaline phosphatase of neutrophils AlPN (r = 0,88-0,91). There was a destabilization of the cellular component of the immune response, characterized by a decrease in the immunoregulatory index by 2.0 times, and activation of the humoral component with an increase in the levels of IgM, IgE and circulating immune complexes by 1.4-1.8 times relative to the control. An imbalance of cytokine regulation was established, where proinflammatory responses with increased cytokine production by 1.5-3.5 times (IL-1β, TNF-α, IL-4) prevail. The relationship between the concentration of nickel in the urine and changes in the parameters of AcPN (r = 0.87), MPn (r = -0.84), IgA (r = -0.72); IL-1β, IL-4, IgE, (r = 0.62-0.71), confirming the priority effect of nickel compounds on the established changes. Conclusion. The identified violations of the immunoreactivity of the workers ‘ body can contribute to the development of immunodeficiency, allergic and autoimmune conditions that underlie occupational and industrial-related diseases. The proposed biomarkers are recommended to be used for early diagnosis of health disorders in workers of electroplating production, formation of “risk groups”, evaluation of the effectiveness of timely preventive and rehabilitation measures.

Temporally auto-correlated predator attacks structure ecological communities

For species regulated by a common predator, the P* rule predicts that the prey species that supports the highest mean predator density (P*) excludes the other prey species. This prediction is re-examined in the presence of temporal fluctuations in the vital rates of the interacting species including predator attack rates. When the fluctuations in predator attack rates are temporally uncorrelated, the P* rule still holds even when the other vital rates are temporally auto-correlated. However, when temporal auto-correlations in attack rates are positive but not too strongly, the prey species can coexist due to the emergence of a positive covariance between predator density and prey vulnerability. This coexistence mechanism is similar to the storage effect for species regulated by a common resource. Strongly positive or negative auto-correlations in attack rates generate a negative covariance between predator density and prey vulnerability and a stochastic priority effect can emerge: with non-zero probability either prey species is excluded. These results highlight how temporally auto-correlated species' interaction rates impact the structure and dynamics of ecological communities.

Bacillus pumilus Group Comparative Genomics: Toward Pangenome Features, Diversity, and Marine Environmental Adaptation

BackgroundMembers of the Bacillus pumilus group (abbreviated as the Bp group) are quite diverse and ubiquitous in marine environments, but little is known about correlation with their terrestrial counterparts. In this study, 16 marine strains that we had isolated before were sequenced and comparative genome analyses were performed with a total of 52 Bp group strains. The analyses included 20 marine isolates (which included the 16 new strains) and 32 terrestrial isolates, and their evolutionary relationships, differentiation, and environmental adaptation.ResultsPhylogenomic analysis revealed that the marine Bp group strains were grouped into three species: B. pumilus, B. altitudinis and B. safensis. All the three share a common ancestor. However, members of B. altitudinis were observed to cluster independently, separating from the other two, thus diverging from the others. Consistent with the universal nature of genes involved in the functioning of the translational machinery, the genes related to translation were enriched in the core genome. Functional genomic analyses revealed that the marine-derived and the terrestrial strains showed differences in certain hypothetical proteins, transcriptional regulators, K+ transporter (TrK) and ABC transporters. However, species differences showed the precedence of environmental adaptation discrepancies. In each species, land specific genes were found with possible functions that likely facilitate survival in diverse terrestrial niches, while marine bacteria were enriched with genes of unknown functions and those related to transcription, phage defense, DNA recombination and repair.ConclusionOur results indicated that the Bp isolates show distinct genomic features even as they share a common core. The marine and land isolates did not evolve independently; the transition between marine and non-marine habitats might have occurred multiple times. The lineage exhibited a priority effect over the niche in driving their dispersal. Certain intra-species niche specific genes could be related to a strain’s adaptation to its respective marine or terrestrial environment(s). In summary, this report describes the systematic evolution of 52 Bp group strains and will facilitate future studies toward understanding their ecological role and adaptation to marine and/or terrestrial environments.

Interactions during growth eclipse interactions during flowering for determining plant fecundity in pollinator-sharing annual plants

Species interactions are foundational to ecological theory, but studies often reduce the complex nature of species interactions. In plant ecology, the result is that interactions during vegetative growth and flowering are considered separately, though both can affect fecundity. Here we use a system of annual flowering plants in the genus Clarkia to ask how interactions during flowering and growth contribute to plant interactions, and if pollinator behaviors explain apparent patterns in plant interactions during flowering. We measure seed success and fecundity of Clarkia focal plants in experimental interaction plots with the effect of pollinators experimentally removed or retained. We also observe pollinator behaviors in the plots and experimental arrays. During flowering, pollinators significantly changed the effect of Clarkia interactions on seed success in 31% of species interactions, and these changes corresponded to pollinator behaviors. Whole-plant fecundity, however, did not depend on interactions between Clarkia; instead, non-Clarkia forbs that grew earlier in the season limited fecundity, constituting a priority effect during vegetative growth. Our study shows that interactions during vegetative growth can preclude the effect of pollinator-mediated interactions on fecundity by limiting potential reproductive output, and that simultaneously studying different modes of interaction allows for understanding the contingency of ecological outcomes.

Influence of cultivation technology elements on yield and water consumption of peas Premier variety under rainfed conditions

Purpose: to identify the optimal combination of the seeding rate of seeds and the background of fertilizers to achieve a high yield of a new peas Premier variety, as well as to study the peculiarities of water consumption of the crop under the soil and climatic conditions of Azov zone Rostov region. Materials and methods. The studies were carried out in Aksai district Rostov region in 2019–2020. The soil of the experimental site is represented by ordinary calcareous medium-thick light loamy chernozem on loess-like loam. The experiments used the Premier pea variety. Factor A: seeding rates (0.8 (control); 1.0; 1.2 million pcs/ha); factor B: fertilizer backgrounds (high – N30Р80K80; medium – N15Р40K40; control without fertilizers) were studied. During the field experiment, the generally accepted methods were used (B. A. Dospekhov, 1985; A. N. Kostyakov, 1961; A. F. Vadyunina, 1986). Results. When growing peas in rainfed conditions, the priority effect on grain yield is provided by the moisture supply of plants during the critical period of water consumption. In years with optimal (GTC = 1.37) and stressful (GTC = 0.22) conditions of this growing season, the difference in yield indicators reached 47.0–51.9 %. The change in the seeding density from 0.8 to 1.0 and 1.2 million pcs/ha contributed to an increase in the average grain yield under different nutritional backgrounds, respectively, by 21.3–25.0 and 34.0–40.5 % compared to control. The fertilizer rate N15Р40K40 increased the peas yield at different sowing densities by 16.0–21.2 %, and a high background (N30Р80K80) – by 38.6–42.2 % compared to natural fertility conditions. The best payback of fertilizers by an increase in yield was obtained in the variant with a high background of nutrition N30P80K80 and a seeding rate of 1.2 million units/ha – 3.32 kg/kg. Conclusions. The best average grain yield was ensured at the rates of fertilization N30P80K80 and seeding of seeds of 1.2 million units/ha, reaching 2.26 t/ha.

Diversity and Geographic Distribution of Ligninolytic Fungi Associated With Castanopsis sieboldii Leaf Litter in Japan

The diversity and geographic pattern of ligninolytic fungi were investigated within the distribution range of an evergreen tree, Castanopsis sieboldii (Fagaceae), in Japan. Fungal isolates obtained from 18 sites in subtropical and temperate regions in Japan were classified into 50 operational taxonomic units in Ascomycota and Basidiomycota according to the base sequence of the rDNA internal transcribed spacer region. Ordination by nonmetric multidimensional scaling showed the separation of fungal compositions between the study sites which was significantly related to the latitude, longitude, and mean annual temperature (MAT) of the study sites. We applied variation partitioning to separate the magnitude of the climatic, spatial, and leaf property factors and found the roles of MAT and spatial factors in structuring fungal assemblages, suggesting the importance of both niche processes and such non-niche processes as priority effect and dispersal limitation. The bleached area on leaf litter was greater at sites with higher MAT and precipitation located at lower latitudes and at sites where some major ligninolytic fungi occurred at greater relative frequencies, indicating that not only the climatic conditions but also the biogeographic patterns of distribution of ligninolytic fungi influence the decomposition of lignin in leaf litter.

Priority effects and season length shape long-term competition dynamics

The relative arrival time of species often affects species interactions within a community, contributing to priority effects. Recent studies on phenological shifts under climate change have generated renewed interest on priority effects, but their role in shaping long-term dynamics of seasonal communities is poorly resolved. Here we use a general stage-structure competition model to determine how different types of priority effects influence long-term coexistence of species in seasonal systems. We show that while shifts in mean and variance of relative arrival time can alter persistence and coexistence conditions of species, these effects depend on season length and type of priority effect. In “slow” systems with one or a few cohorts per season, changes in mean and seasonal variation of relative arrival time strongly altered species persistence through trait-mediated priority effects. In contrast, competition outcome in “fast” systems is largely determined by numeric priority effects due to interaction between many overlapping generations. These results suggest that empirically observed priority effects may arise from fundamentally different mechanisms, and that fast-generating systems may be less impacted by seasonal variation in phenology. Our model provides important insight into how natural communities respond to increasing variation in phenology over seasons under climate change.

Evolutionary mechanisms that determine which bacterial genes are carried on plasmids

The evolutionary pressures that determine the location (chromosomal or plasmid-borne) of bacterial genes are not fully understood. We investigate these pressures through mathematical modelling in the context of antibiotic resistance, which is often found on plasmids. Our central finding is that gene location is under positive frequency-dependent selection, which can keep moderately beneficial genes on plasmids, despite occasional plasmid loss. For these genes, positive frequency-dependence leads to a priority effect: whichever form is acquired first has time to increase in frequency and thus become difficult to displace. We therefore propose that some traits, including antibiotic resistance, are found on plasmids because they are typically acquired on plasmids. Gene flow between plasmid and chromosome allows chromosomal forms to arise, but positive frequency-dependent selection prevents these from establishing. We also re-visit some previous theory in light of our results, with implications for plasmid persistence and the role of local adaptation in plasmid dynamics.

The application of community ecology theory to co-infections in wildlife hosts

Priority effect theory, a foundational concept from community ecology, states that the order and timing of species arrival during species assembly can affect species composition. Although this theory has been applied to co-infecting parasite species, it has almost always been with a single time lag between co-infecting parasites. Thus, how the timing of parasite species arrival affects co-infections and disease remains poorly understood. To address this gap in the literature, we exposed post-metamorphic Cuban tree frogs (Osteopilus septentrionalis) to Ranavirus, the fungus Batrachochytrium dendrobatidis (Bd), a nematode Aplectana hamatospicula, or pairs of these parasites either simultaneously or sequentially at a range of time lags and quantified load of the secondary parasite and host growth, survival and parasite tolerance. Prior exposure to Bd or A. hamatospicula significantly increased viral loads relative to hosts singly infected with Ranavirus, whereas A. hamatospicula loads in hosts were higher when co-exposed to Bd than when co-exposed to Ranavirus. There was a significant positive relationship between time since Ranavirus infection and Bd load, and prior exposure to A. hamatospicula decreased Bd loads compared to simultaneous co-infection with these parasites. Infections with Bd and Ranavirus either singly or in co-infections decreased host growth and survival. This research reveals that time lags between co-infections can affect parasite loads, in line with priority effects theory. As co-infections in the field are unlikely to be simultaneous, an understanding of when co-infections are impacted by time lags between parasite exposures may play a major role in controlling problematic co-infections.