Prokaryotic Community Composition Affected by Seasonal Changes in Physicochemical Properties of Water in Peat Bog Lakes

Based on a three-year study on the prokaryotic community composition in peat bog lakes surrounded by a floating mat of Sphagnum sp. moss in the conditions of Northeast Poland (Central Europe), we verified the relationship between 20 water parameters and main Eubacteria and Archaea phyla for specific sites: the subsurface (pelagic zone), near-bottom (benthic zone), and the Sphagnum mat (ecotone zone). Abundance and composition of the main aquatic bacteria phyla (Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria, Deltaproteobacteria, Actinobacteria, and Cytophaga-Flavobacteria) and Archaea were associated with different combinations of physico-chemical parameters of water, and followed temporal variations of temperature, dissolved organic carbon (DOC), aromaticity, and water color. Redundancy analysis (RDA) showed that water acidity is a less significant predictor of bacterial activity; however, we have found Betaproteobacteria negatively correlated (r = −0.49, p = 0.01), while Actinobacteria positively correlated (r = 0.21, p = 0.05) to pH. This relation was the most significant in the ecotone zone. In the overall bacteria community structure Betaproteobacteria dominated (18.3%) regardless of site or season, except for winter when, at low temperatures and DOC concentrations, Actinobacteria increased to 22.9%. The Archaea fraction was uniform (11%) in seasons and sites and showed no specific preferences to physico-chemical predictors. Although the water parameters from the Sphagnum mat did not differ significantly from pelagic water, its role as a source of allochthonous organic matter is crucial for bacteria activity. The relations between peat bog lake attributes and seasonal changes in bacterial diversity demonstrated a distinct divergent pattern for each prokaryote. Obtaining results will provide support for any future evaluation of the effects of environmental variables on prokaryotic community structures in peat bog lakes

Low basal metabolic rate as a risk factor for development of insulin resistance and type 2 diabetes

Introduction Identification of physiological factors influencing susceptibility to insulin resistance and type 2 diabetes (T2D) remains an important challenge for biology and medicine. Numerous studies reported energy expenditures as one of those components directly linked to T2D, with noticeable increase of basal metabolic rate (BMR) associated with the progression of insulin resistance. Conversely, the putative link between genetic, rather than phenotypic, determination of BMR and predisposition to development of T2D remains little studied. In particular, low BMR may constitute a considerable risk factor predisposing to development of T2D.Research design and methods We analyzed the development of insulin resistance and T2D in 20-week-old male laboratory mice originating from three independent genetic line types. Two of those lines were subjected to divergent, non-replicated selection towards high or low body mass-corrected BMR. The third line type was non-selected and consisted of randomly bred animals serving as an outgroup (reference) to the selected line types. To induce insulin resistance, mice were fed for 8 weeks with a high fat diet; the T2D was induced by injection with a single dose of streptozotocin and further promotion with high fat diet. As markers for insulin resistance and T2D advancement, we followed the changes in body mass, fasting blood glucose, insulin level, lipid profile and mTOR expression.Results We found BMR-associated differentiation in standard diabetic indexes between studied metabolic lines. In particular, mice with low BMR were characterized by faster body mass gain, blood glucose gain and deterioration in lipid profile. In contrast, high BMR mice were characterized by markedly higher expression of the mTOR, which may be associated with much slower development of T2D.Conclusions Our study suggests that genetically determined low BMR makeup involves metabolism-specific pathways increasing the risk of development of insulin resistance and T2D

Liver injury in patients with COVID-19 without underlying liver disease

SARS-CoV-2 shows a high affinity for the ACE-2 receptor, present on the epithelial cells of the upper and lower respiratory tract, within the intestine, kidneys, heart, testes, biliary epithelium, and—where it is particularly challenging—on vascular endothelial cells. Liver involvement is a rare manifestation of COVID-19. Material and Methods: We reviewed 450 patients admitted due to the fact of SARS-CoV-2 infection (COVID-19) including 88 with liver injury. Based on medical history and previous laboratory test results, we excluded cases of underlying liver disease. The analysis involved a clinical course of COVID-19 in patients without underlying liver disease as well as the type and course of liver injury. Results: Signs and symptoms of liver injury were present in 20% of patients, mostly presenting as a mixed-type pattern of injury with less common cases of standalone hepatocellular (parenchymal) or cholestatic injury. The liver injury symptoms resolved at the end of inpatient treatment in 20% of cases. Sixteen patients died with no cases where liver injury would be deemed a cause of death. Conclusions: (1) Liver injury secondary to COVID-19 was mild, and in in 20%, the signs and symptoms of liver injury resolved by the end of hospitalization. (2) It seems that liver injury in patients with COVID-19 was not associated with a higher risk of mortality. (3) The underlying mechanism of liver injury as well as its sequelae are not fully known. Therefore, caution and further monitoring are advised, especially in patients whose liver function tests have not returned to normal values