FIRST REPORT ON TRUFFLE-INHABITING FUNGI AND METAGENOMIC COMMUNITIES OF TUBER AESTIVUM COLLECTED IN RUSSIA

Truffles are one of the least studied groups of fungi in terms of their biological and biotechnological aspects. This study aimed to isolate truffle-inhabiting fungi and assess the metagenomic communities of the most common Russian summer truffle, Tuber aestivum. This study is the first to characterize the biodiversity of prokaryotic and eukaryotic organisms living in the truffle T. aestivum using molecular analysis and sequencing. Plant pathogens involved in a symbiotic relationship with truffles were identified by sequencing the hypervariable fragments of the 16S rRNA and 18S rRNA genes. In addition, some strains of fungal symbionts and likely pathogens were isolated and recognized for the first time from the truffles. This study also compared and characterized the general diversity and distribution of microbial taxa of T. aestivum collected in Russia and Europe. The results revealed that the Russian and European truffle study materials demonstrated high similarity. In addition to the truffles, representatives of bacteria, fungi, and protists were found in the fruiting bodies. Many of these prokaryotic and eukaryotic species inhabiting truffles might influence them, help them form mycorrhizae with trees, and regulate biological processes. Thus, truffles are interesting and promising sources for modern biotechnological and agricultural studies

Screening, identification, and antibiotic activity of secondary metabolites of Penicillium sp. LPB2019K3-2 isolated from endemic amphipods of Lake Baikal

This study aimed to assess the influence of nutrient media content on the production of antibiotics and the ability of water fungi isolated from lake Baikal to synthesize novel natural products. Interest in this topic stems from the high demand for new drugs, and studies are carried out via the screening of new natural products with biological activity produced by unstudied or extremophilic microorganisms. For this study, a strain of Penicillium sp. was isolated from endemic Baikal phytophagous amphipod species. Here, we identified natural products using the following classical assays: biotechnological cultivation, MALDI identification of the strain, natural product extraction, antimicrobial activity determination, and modern methods such as HPLC-MS for the dereplication and description of natural products. It was found that many detected metabolites were not included in the most extensive database. Most of the identified metabolites were characterized by their biological activity and demonstrated antibiotic activity against model Gram-positive and Gram-negative bacteria. The isolated strain of water fungus produced penicolinate B, meleagrin A, austinoneol A, andrastin A, and other natural products. Additionally, we show that the synthesis of low-molecular-weight natural products depends on the composition of the microbiological nutrient media used for cultivation. Thus, although the golden age of antibiotics ended many years ago and microscopic fungi are well studied producers of known antibiotics, the water fungi of the Lake Baikal ecosystem possess great potential in the search for new natural products for the development of new drugs. These natural products can become new pharmaceuticals and can be used in therapy to treat new diseases such as SARS, MERS, H5N1, etc

Early mobilisation in critically ill COVID-19 patients: a subanalysis of the ESICM-initiated UNITE-COVID observational study

Background Early mobilisation (EM) is an intervention that may improve the outcome of critically ill patients. There is limited data on EM in COVID-19 patients and its use during the first pandemic wave. Methods This is a pre-planned subanalysis of the ESICM UNITE-COVID, an international multicenter observational study involving critically ill COVID-19 patients in the ICU between February 15th and May 15th, 2020. We analysed variables associated with the initiation of EM (within 72 h of ICU admission) and explored the impact of EM on mortality, ICU and hospital length of stay, as well as discharge location. Statistical analyses were done using (generalised) linear mixed-effect models and ANOVAs. Results Mobilisation data from 4190 patients from 280 ICUs in 45 countries were analysed. 1114 (26.6%) of these patients received mobilisation within 72 h after ICU admission; 3076 (73.4%) did not. In our analysis of factors associated with EM, mechanical ventilation at admission (OR 0.29; 95% CI 0.25, 0.35; p = 0.001), higher age (OR 0.99; 95% CI 0.98, 1.00; p ≤ 0.001), pre-existing asthma (OR 0.84; 95% CI 0.73, 0.98; p = 0.028), and pre-existing kidney disease (OR 0.84; 95% CI 0.71, 0.99; p = 0.036) were negatively associated with the initiation of EM. EM was associated with a higher chance of being discharged home (OR 1.31; 95% CI 1.08, 1.58; p = 0.007) but was not associated with length of stay in ICU (adj. difference 0.91 days; 95% CI − 0.47, 1.37, p = 0.34) and hospital (adj. difference 1.4 days; 95% CI − 0.62, 2.35, p = 0.24) or mortality (OR 0.88; 95% CI 0.7, 1.09, p = 0.24) when adjusted for covariates. Conclusions Our findings demonstrate that a quarter of COVID-19 patients received EM. There was no association found between EM in COVID-19 patients' ICU and hospital length of stay or mortality. However, EM in COVID-19 patients was associated with increased odds of being discharged home rather than to a care facility. Trial registration ClinicalTrials.gov: NCT04836065 (retrospectively registered April 8th 2021)

Determination of the critical values of flow parameters characteristic of the alignment of cylindrical nano-objects in suspensions

A method for determining the critical values of the flow speed and the flow constriction degree characteristic of the alignment of cylindrical nano-objects in a flowing suspension is proposed. Previously, the alignment process of cylindrical nano-objects in suspensions was investigated by using birefringence of the polarized light and the small-angle X-ray scattering. While both methods are suitable for measuring the alignment degree of cylindrical nano-objects in suspensions diluted down to low concentrations, they are restricted for the application to undiluted concentrated suspensions because of non-transparency and multiple scattering of X-rays. In addition, the use of the second method requires an expensive synchrotron equipment. We present a simple and faster method based on the direct ultrasound attenuation measurements of longitudinal viscosity of a suspension containing cylindrical nano-objects, which decreases monotonically, approaching its asymptotic value with increase in the flow speed and the flow constriction degree. The principle and advantages of the proposed method are as follows: • The cylindrical nano-objects align along an accelerated flow at overcritical values of the flow speed and the constriction degree. • The critical values correspond to the state of a suspension possessing viscosity close to the asymptotic value. • The method is applicable to undiluted concentrated suspensions, including opaque ones

α-Tocopherol at Nanomolar Concentration Protects Cortical Neurons against Oxidative Stress

The aim of the present work is to study the mechanism of the α-tocopherol (α-T) protective action at nanomolar and micromolar concentrations against H2O2-induced brain cortical neuron death. The mechanism of α-T action on neurons at its nanomolar concentrations characteristic for brain extracellular space has not been practically studied yet. Preincubation with nanomolar and micromolar α-T for 18 h was found to increase the viability of cortical neurons exposed to H2O2; α-T effect was concentration-dependent in the nanomolar range. However, preincubation with nanomolar α-T for 30 min was not effective. Nanomolar and micromolar α-T decreased the reactive oxygen species accumulation induced in cortical neurons by the prooxidant. Using immunoblotting it was shown that preincubation with α-T at nanomolar and micromolar concentrations for 18 h prevented Akt inactivation and decreased PKCδ activation induced in cortical neurons by H2O2. α-T prevented the ERK1/2 sustained activation during 24 h caused by H2O2. α-T at nanomolar and micromolar concentrations prevented a great increase of the proapoptotic to antiapoptotic proteins (Bax/Bcl-2) ratio, elicited by neuron exposure to H2O2. The similar neuron protection mechanism by nanomolar and micromolar α-T suggests that a “more is better” approach to patients’ supplementation with vitamin E or α-T is not reasonable

α-Tocopherol at Nanomolar Concentration Protects PC12 Cells from Hydrogen Peroxide-Induced Death and Modulates Protein Kinase Activities

The aim of this work was to compare protective and anti-apoptotic effects of α-tocopherol at nanomolar and micromolar concentrations against 0.2 mM H2O2-induced toxicity in the PC12 neuronal cell line and to reveal protein kinases that contribute to α-tocopherol protective action. The protection by 100 nM α-tocopherol against H2O2-induced PC12 cell death was pronounced if the time of pre-incubation with α-tocopherol was 3–18 h. For the first time, the protective effect of α-tocopherol was shown to depend on its concentration in the nanomolar range (1 nM < 10 nM < 100 nM), if the pre-incubation time was 18 h. Nanomolar and micromolar α-tocopherol decreased the number of PC12 cells in late apoptosis induced by H2O2 to the same extent if pre-incubation time was 18 h. Immunoblotting data showed that α-tocopherol markedly diminished the time of maximal activation of extracellular signal-regulated kinase 1/2 (ERK 1/2) and protein kinase B (Akt)-induced in PC12 cells by H2O2. Inhibitors of MEK 1/2, PI 3-kinase and protein kinase C (PKC) diminished the protective effect of α-tocopherol against H2O2-initiated toxicity if the pre-incubation time was long. The modulation of ERK 1/2, Akt and PKC activities appears to participate in the protection by α-tocopherol against H2O2-induced death of PC12 cells. The data obtained suggest that inhibition by α-tocopherol in late stage ERK 1/2 and Akt activation induced by H2O2 in PC12 cells makes contribution to its protective effect, while total inhibition of these enzymes is not protective

Metabolically Active Prokaryotic Complex in Grassland and Forests’ Sod-Podzol under Polycyclic Aromatic Hydrocarbon Influence

Molecular genetic techniques (FISH, RT-PCR, and metagenomic analysis) were used to investigate the comparative functional biodiversity in the prokaryotic complex in grassland and forests’ sod-podzol under polycyclic aromatic hydrocarbon influence. The polluted samples showed a decrease in the biomass of the prokaryotic community representatives and a change in the metabolically active dominants–representatives of the Bacteria and Archaea domains compared to the control samples. The suppression of the metabolic activity of prokaryote cells under the influence of PAHs in sod-podzolic soil under meadow vegetation was more pronounced compared to soils under forest vegetation. The representatives of prokaryotes that are sensitive and resistant to the studied PAHs were identified. The representatives of the phylogenetic groups from the bacterial complex resistant to PAH pollution were Proteobacteria (Alphaproteobacteria), Bacteroidetes, Firmicutes, Chloroflexi, and Thaumarhaeota in the archaeal complex. Representatives of the phylum Acidobacteria and Actinobacteria (Streptosporangiales) are noted among those sensitive to PAH contamination. The presence and expression of the functional alkane monooxygenase (alkB) gene were established in all the experimental variants studied. In the plant variants, the number of copies of alkB genes increased by an order of magnitude and the biomass of metabolically active prokaryotic representatives with the functional alkB gene doubled compared to the unpolluted territories. The copy number index of the alkB gene can be used as one of the parameters when characterizing an ecosystem for the presence of PAH pollutants