Shift in potential pathogenic bacteria during permafrost degradation on the Qinghai-Tibet Plateau.

Permafrost acts as a potential pathogen reservoir. With accelerating climate change and intensifying permafrost degradation, the release of these pathogens poses significant threats to ecosystems and public health. However, the changes in pathogenic communities during permafrost degradation remain unclear. This study utilized quantitative PCR and Illumina high-throughput sequencing to analyze the composition and quantities of potential pathogenic bacteria in four types of permafrost soil on the northeast edge of the Qinghai-Tibet Plateau (QTP): sub-stable permafrost (SSP), transition permafrost (TP), unstable permafrost (UP), and extremely unstable permafrost (EUP). The results showed that during permafrost degradation, the quantity of potential pathogenic bacteria decreased from 7.8 × 106 to 3.1 × 106 copies/g. Both the Richness and Shannon indices initially declined from SSP, to TP, UP, and then began to rise when permafrost degraded to EUP. A total of 216 potential pathogenic bacterial species were identified, including 166 animal pathogens, 28 zoonotic pathogens, and 22 plant pathogens. The pathogenic community intergroup differences (ANOSIM), unique taxa, and dominant pathogen analysis indicated the significant changes in pathogenic communities during permafrost degradation. The potential pathogenic community was significantly influenced by non-pathogenic bacterial communities (Procrustes analysis), with soil moisture being the primary environmental factor, followed by TDS, soil organic carbon, and total nitrogen. SourceTracker2 analysis indicated that the majority of potential pathogenic bacteria in the soil originated from external sources, only a small portion coming from the permafrost itself. These findings suggest that a large number of pathogens were released into the environment while also preserving amount from external sources. It elucidates that each stage of permafrost degradation presents unique biosecurity risks. This study highlights the release and redistribution of pathogenic bacteria associated with the potential public health risks. It provides the crucial insights into the ecological dynamics of permafrost degradation, emphasizing the need for ongoing monitoring and proactive management strategies.

Rumen microbiota helps Tibetan sheep obtain energy more efficiently to survive in the extreme environment of the Qinghai-Tibet Plateau.

Introduction: T-sheep and H-sheep exhibit different environmental adaptability and production performance. The rumen microbiome has co-evolved with hosts and plays a vital role in nutrient digestion and energy metabolism. In our previous study, we found that T-sheep have a higher efficiency in energy metabolism than H-sheep, but the rumen microbial community remains unclear. Methods: In this study, we determined the rumen bacterial profile and rumen fermentation parameters to reveal the bacterial profiles and predictive functions among breeds and diets with four different energy levels, as well as the correlation between bacterial profiles and rumen fermentation characteristics. Results: The results showed that the rumen total volatile fatty acids (VFAs), acetate, butyrate, total branched-chain VFAs, iso-butyrate, and iso-valerate were higher in T-sheep than H-sheep. The alpha diversity of ruminal bacteria is not affected by dietary energy, but it shows a distinction between the sheep breeds. Specifically, T-sheep rumen bacteria exhibit higher alpha diversity than H-sheep. The beta diversity of ruminal bacteria is not influenced by dietary energy or sheep breeds, indicating similar communities of ruminal bacteria between different diets and sheep breeds. The phyla of Bacteroidetes and Firmicutes predominate in the rumen, with a higher relative abundance of Firmicutes observed in T-sheep than H-sheep. The two most abundant genera in the rumen were Prevotella 1 and Rikenellaceae RC9 gut group. Prevotella 1 is the predominant bacterial genus in the rumen of H-sheep, while the Rikenellaceae RC9 gut group dominates in the rumen of T-sheep. Microbial co-occurrence network analysis reveals that variations in rumen fermentation characteristics result from differences in module abundance, with a higher abundance of VFA-producing modules observed in the rumen of T-sheep. Microbial function prediction analysis showed that dietary energy rarely alters the functional composition of rumen bacteria. However, there were differences in the functions of rumen bacteria between sheep breeds, with T-sheep showing a greater emphasis on energy metabolism-related functions, while H-sheep showed a greater emphasis on protein metabolism-related functions. Discussion: These findings provide evidence of the special rumen microbial community that helps T-sheep efficiently obtain energy from low-protein and low-energy diets, enabling them to survive in the extreme environment of the Qinghai-Tibet Plateau.

The diversity and risk of potential pathogenic bacteria on the surface of glaciers in the southeastern Tibetan Plateau.

Glaciers, which constitute the world's largest global freshwater reservoir, are also natural microbial repositories. The frequent pandemic in recent years underscored the potential biosafety risks associated with the release of microorganisms from the accelerated melting of glaciers due to global warming. However, the characteristics of pathogenic microorganisms in glaciers are not well understood. The glacier surface is the primary area where glacier melting occurs that is often the main subject of research on the dynamics of pathogenic microbial communities in efforts to assess glacier biosafety risks and devise preventive measures. In this study, high-throughput sequencing and quantitative polymerase chain reaction methods were employed in analyses of the composition and quantities of potential pathogenic bacteria on the surfaces of glaciers in the southeastern Tibetan Plateau. The study identified 441 potential pathogenic species ranging from 215 to 4.39 × 1011 copies/g, with notable seasonal and environmental variations being found in the composition and quantity of potential pathogens. The highest level of diversity was observed in April and snow, while the highest quantities were observed in October and cryoconite. Host analysis revealed that >70 % of the species were pathogens affecting animals, with the highest proportion of zoonotic pathogens being observed in April. Analysis of aerosols and glacial meltwater dispersion suggested that these microbes originated from West Asia, primarily affecting the central and southern regions of China. Null model analysis indicated that the assembly of potential pathogenic microbial communities on glacier surfaces was largely governed by deterministic processes. In conclusion, potential pathogenic bacteria on glacier surfaces mainly originated from the snow and exhibited significant temporal and spatial variation patterns. These findings can be used to enhance researchers' ability to predict potential biosafety risks associated with pathogenic bacteria in glaciers and to prevent their negative impact on populations and ecological systems.

Radiation-resistant bacteria in desiccated soil and their potentiality in applied sciences.

A rich diversity of radiation-resistant (Rr) and desiccation-resistant (Dr) bacteria has been found in arid habitats of the world. Evidence from scientific research has linked their origin to reactive oxygen species (ROS) intermediates. Rr and Dr. bacteria of arid regions have the potential to regulate imbalance radicals and evade a higher dose of radiation and oxidation than bacterial species of non-arid regions. Photochemical-activated ROS in Rr bacteria is run through photo-induction of electron transfer. A hypothetical model of the biogeochemical cycle based on solar radiation and desiccation. These selective stresses generate oxidative radicals for a short span with strong reactivity and toxic effects. Desert-inhibiting Rr bacteria efficiently evade ROS toxicity with an evolved antioxidant system and other defensive pathways. The imbalanced radicals in physiological disorders, cancer, and lung diseases could be neutralized by a self-sustaining evolved Rr bacteria antioxidant system. The direct link of evolved antioxidant system with intermediate ROS and indirect influence of radiation and desiccation provide useful insight into richness, ecological diversity, and origin of Rr bacteria capabilities. The distinguishing features of Rr bacteria in deserts present a fertile research area with promising applications in the pharmaceutical industry, genetic engineering, biological therapy, biological transformation, bioremediation, industrial biotechnology, and astrobiology.

Forest management positively reshapes the phyllosphere bacterial community and improves community stability.

Research has shown that forest management can improve the post-drought growth and resilience of Qinghai spruce in the eastern Qilian Mountains, located on the northeastern Tibetan Plateau. However, the impact of such management on the tree-associated phyllosphere microbiome is not yet fully understood. This study provides new evidence of positive forest management effects on the phyllosphere microbiome after extreme drought, from the perspectives of community diversity, structure, network inference, keystone species, and assembly processes. In managed Qinghai spruce forest, the α-diversity of the phyllosphere bacterial communities increased, whereas the ß-diversity decreased. In addition, the phyllosphere bacterial community became more stable and resistant, yet less complex, following forest management. Keystone species inferred from a bacterial network also changed under forest management. Furthermore, forest management mediated changes in community assembly processes, intensifying the influence of determinacy, while diminishing that of stochasticity. These findings support the hypothesis that management can re-assemble the phyllosphere bacterial community, enhance community stability, and ultimately improve tree growth. Overall, the study highlights the importance of forest management on the phyllosphere microbiome and furnishes new insights into forest conservation from the perspective of managing microbial processes and effects.

Saxibacter everestensis gen. nov., sp. nov., A Novel Member of the Family Brevibacteriaceae, Isolated from the North Slope of Mount Everest.

We isolated and analyzed a novel, Gram-stain-positive, aerobic, rod-shaped, non-motile actinobacterium, designated as strain ZFBP1038T, from rock sampled on the north slope of Mount Everest. The growth requirements of this strain were 10-37 °C, pH 4-10, and 0-6% (w/v) NaCl. The sole respiratory quinone was MK-9, and the major fatty acids were anteiso-C15:0 and iso-C17:0. Peptidoglycan containing meso-diaminopimelic acid, ribose, and glucose were the major cell wall sugars, while polar lipids included diphosphatidyl glycerol, phosphatidyl glycerol, an unidentified phospholipid, and an unidentified glycolipid. A phylogenetic analysis based on 16S rRNA gene sequences showed that strain ZFBP1038T has the highest similarity with Spelaeicoccus albus DSM 26341 T (96.02%). ZFBP1038T formed a distinct monophyletic clade within the family Brevibacteriaceae and was distantly related to the genus Spelaeicoccus. The G + C content of strain ZFBP1038T was 63.65 mol% and the genome size was 4.05 Mb. Digital DNA-DNA hybridization, average nucleotide identity, and average amino acid identity values between the genomes of strain ZFBP1038T and representative reference strains were 19.3-25.2, 68.0-71.0, and 52.8-60.1%, respectively. Phylogenetic, phenotypic, and chemotaxonomic characteristics as well as comparative genome analyses suggested that strain ZFBP1038T represents a novel species of a new genus, for which the name Saxibacter gen. nov., sp. nov. was assigned with the type strain Saxibacter everestensis ZFBP1038T (= EE 014 T = GDMCC 1.3024 T = JCM 35335 T).

Imaging of Sarcopenia in Type 2 Diabetes Mellitus.

Sarcopenia is an age-related condition characterized by the loss of skeletal muscle mass, muscular strength, and muscle function. In older adults, type 2 diabetes mellitus (T2DM) constitutes a significant health burden. Skeletal muscle damage and deterioration have emerged as novel chronic complications in patients with diabetes, often linked to their increased longevity. Diabetic sarcopenia has been associated with increased rates of hospitalization, cardiovascular events, and mortality. Nevertheless, effectively managing metabolic disorders in patients with T2DM through appropriate therapeutic interventions could potentially mitigate the risk of sarcopenia. Utilizing imaging technologies holds substantial clinical significance in the early detection of skeletal muscle mass alterations associated with sarcopenia. Such detection is pivotal for arresting disease progression and preserving patients' quality of life. These imaging modalities offer reproducible and consistent patterns over time, as they all provide varying degrees of quantitative data. This review primarily delves into the application of dual-energy X-ray absorptiometry, computed tomography, magnetic resonance imaging, and ultrasound for both qualitative and quantitative assessments of muscle mass in patients with T2DM. It also juxtaposes the merits and limitations of these four techniques. By understanding the nuances of each method, clinicians can discern how best to apply them in diverse clinical scenarios.

A novel UV-resistant bacterium Sphingomonas endolithica sp. nov., and genomic analysis, isolated from the north slope of Mount Everest.

Gram-stain-negative, aerobic, rod-shaped, non-motile bacterium strain ZFBP2030T was isolated from a rock on the North slope of Mount Everest. This strain contained a unique ubiquinone-10 (Q-10) as a predominant respiratory quinone. Among the tested fatty acids, the strain contained summed feature 8, C14:0 2OH, and C16:0, as major cellular fatty acids. The polar lipid profile contained phosphatidyl glycerol, phosphatidyl ethanolamine, three unidentified phospholipids, two unidentified aminolipids, and six unidentified lipids. The cell-wall peptidoglycan was a meso-diaminopimelic acid, and cell-wall sugars were ribose and galactose. Phylogenetic analyses based on 16S rRNA gene sequence revealed that strain ZFBP2030T was a member of the genus Sphingomonas, exhibiting high sequence similarity to the 16S rRNA gene sequences of Sphingomonas aliaeris DH-S5T (97.9%), Sphingomonas alpina DSM 22537T (97.3%) and Sphingomonas hylomeconis CCTCC AB 2013304T (97.0%). The 16S rRNA gene sequence similarity between ZFBP2030T and other typical strains was less than 97.0%. The average amino acid identity values, average nucleotide identity, and digital DNA-DNA hybridization values between strain ZFBP2030T and its highest sequence similarity strains were 56.9-79.9%, 65.1-82.2%, and 19.3-25.8%, respectively. The whole-genome size of the novel strain ZFBP2030T was 4.1 Mbp, annotated with 3838 protein-coding genes and 54 RNA genes. Moreover, DNA G + C content was 64.7 mol%. Stress-related functions predicted in the subsystem classification of the strain ZFBP2030T genome included osmotic, oxidative, cold/heat shock, detoxification, and periplasmic stress responses. The overall results of this study clearly showed that strain ZFBP2030T is a novel species of the genus Sphingomonas, for which the name Sphingomonas endolithica sp. nov. is proposed. The type of strain is ZFBP2030T (= EE 013T = GDMCC 1.3123T = JCM 35386T).

Potentilla parvifolia strongly influenced soil microbial community and environmental effect along an altitudinal gradient in central Qilian Mountains in western China.

The Qilian Mountains (QLMs) form an important ecological security barrier in western China and a priority area for biodiversity conservation. Potentilla parvifolia is a widespread species in the mid-high altitudes of the QLMs and has continuously migrated to higher altitudes in recent years. Understanding the effects of P. parvifolia on microbial community characteristics is important for exploring future changes in soil biogeochemical processes in the QLMs. This study found that P. parvifolia has profound effects on the community structure and ecological functions of soil microorganisms. The stability and complexity of the root zone microbial co-occurrence network were significantly higher than those of bare soils. There was a distinct altitudinal gradient in the effect of P. parvifolia on soil microbial community characteristics. At an elevation of 3204 m, P. parvifolia promoted the accumulation of carbon, nitrogen, and phosphorus and increased sucrase activity and soil C/N while significantly improving the community richness index of fungi (p < .05) compared with that of bacteria and the relative abundance of Ascomycota. The alpha diversity of fungi in the root zone soil of P. parvifolia was also significantly increased at 3550 m altitude. Furthermore, the community similarity distance matrix of fungi showed an evident separation at 3204 m. However, at an altitude of 3750 m, P. parvifolia mainly affected the bacterial community. Potentilla parvifolia increased the bacterial community richness. This is in agreement with the findings based on the functional prediction that P. parvifolia favors the growth and enrichment of denitrifying communities at 3550 and 3750 m. The results provide a scientific basis for predicting the evolutionary trends of the effects of P. parvifolia on soil microbial communities and functions and have important implications for ecological governance in the QLMs.

Comparative genomics reveals environmental adaptability and antimicrobial activity of a novel Streptomyces isolated from soil under black Gobi rocks.

A novel Streptomyces strain, designated 3_2T, was isolated from soil under the black Gobi rock sample of Northwest China. The taxonomic position of this strain was revealed by a polyphasic approach. Comparative analysis of the 16S rRNA gene sequences indicated that 3_2T was closely related to the members of the genus Streptomyces, with the highest similarity to Streptomyces rimosus subsp. rimosus CGMCC 4.1438 (99.17%), Streptomyces sioyaensis DSM 40032 (98.97%). Strain 3_2T can grow in media up to 13% NaCl. The genomic DNA G + C content of strain 3_2T was 69.9%. We obtained the genomes of 22 Streptomyces strains similar to strain 3_2T, compared the average nucleotide similarity, dDDH and average amino acid identity, and found that the genomic similarity of the new isolate 3_2T to all strains was below the threshold for interspecies classification. Chemotaxonomic data revealed that strain 3_2T possessed MK-9 (H6) and MK-9 (H8) as the major menaquinones. The cell wall contained LL-diaminopimelic acid (LL-DAP) and the whole-cell sugars were ribose and glucose. The major fatty acid methyl esters were iso-C16:0 (23.6%) and anteiso-C15:0 (10.4%). The fermentation products of strain 3_2T were inhibitory to Staphylococcus aureus and Bacillus thuringiensi. The genome of 3_2T was further predicted using anti-smash and the strain was found to encode the production of 41 secondary metabolites, and these gene clusters may be key to the good inhibitory activity exhibited by the strain. Genomic analysis revealed that strain 3_2T can encode genes that produce a variety of genes in response to environmental stresses, including cold shock, detoxification, heat shock, osmotic stress, oxidative stress, and these genes may play a key role in the harsh environment in which the strain can survive. Therefore, this strain represents a novel Streptomyces species, for which the name Streptomyces halobius sp. nov. is proposed. The type strain is 3_2T (= JCM 34935T = GDMCC 4.217T).

Low-intensity ultrasound combined with arsenic trioxide induced apoptosis of glioma via EGFR/AKT/mTOR.

AIMS: This study aimed to explore whether low-intensity ultrasound (LIUS) combined with low-concentration arsenic trioxide (ATO) could inhibit the proliferation of glioma and, if so, to clarify the potential mechanism. MAIN METHODS: The effects of ATO and LIUS alone or in combination on glioma were examined by CCK8, EdU, and flow cytometry assays. Western blot analysis was used to detect changes in expression of apoptosis-related proteins and their effects on the EGFR/AKT/mTOR pathway. The effects of ATO and LIUS were verified in vivo in orthotopic xenograft models, and tumor size, arsenic content in brain tissue, survival, and immunohistochemical changes were observed. KEY FINDINGS: LIUS enhanced the inhibitory effect of ATO on the proliferation of glioma, and EGF reversed the proliferation inhibition and protein changes induced by ATO and LIUS. The anti-glioma effect of ATO combined with LIUS was related to downstream AKT/mTOR pathway changes caused by inhibition of EGFR activation, which enhanced apoptosis of U87MG and U373 cells. In vivo experiments showed significant increases in arsenic content in brain tissue, as well as decreased tumor sizes and longer survival times in the combined treatment group compared with other groups. The trends of immunohistochemical protein changes were consistent with the in vitro results. SIGNIFICANCE: This study showed that LIUS enables ATO to exert anti-glioma effects at a safe dose by inhibiting the activation of EGFR and the downstream AKT/mTOR pathway to regulate apoptosis. LIUS in combination with ATO is a promising novel method for treating glioma and could improve patient prognosis.

Distribution patterns and functional characteristics of soil bacterial communities in desert ecosystems of northern China.

Deserts are extremely arid environments where life is exposed to multiple environmental stresses, including low water availability, high temperatures, intense radiation environments and soil carbon and nitrogen limitation. Microorganisms have enormous potential applications due to their unique physiological adaptation mechanisms, extensive involvement in geochemical cycles and production of new antibiotics, among many other characteristics. With the increasing amount of open data provides unprecedented opportunities to further reveal bacterial biodiversity and its global role in ecosystem function. Through the collection of published high-quality sequencing data supplemented with experimental findings, we investigated the distribution characteristics and functional properties of bacteria in desert ecosystems in northern China. We show that there are significant differences in bacterial diversity among different sandy areas, and that soil properties and climatic factors are the main factors affecting bacterial diversity in desert ecosystems. The mean annual precipitation in growing season, soil organic carbon, total nitrogen and total phosphorus had significant effects on the diversity of desert bacteria and main bacteria. Desert bacteria primarily participate in the macromolecular decomposition, phototrophy, and geochemical cycling of nitrogen. These findings deepen our understanding of the regional-scale soil microbial diversity patterns in Chinese desert ecosystems and broaden our understanding of the ecological functions carried out by bacteria in these environments.

The Distribution and Influencing Factors of Hypolithic Microbial Communities in the Hexi Corridor.

The Hexi Corridor is an arid region in northwestern China, where hypoliths are widely distributed, resulting from large amounts of translucent stone pavements. In this region, the water and heat distributions are uneven, with a descent gradient from east to west, which can affect the area's biological composition. The impact of environmental heterogeneity on the distribution of hypolithic microbial communities in this area is poorly understood, and this is an ideal location to investigate the factors that may influence the composition and structure of hypolithic microbial communities. An investigation of different sites with differences in precipitation between east and west revealed that the colonization rate decreased from 91.8% to 17.5% in the hypolithic community. Environmental heterogeneity influenced both the structure and function of the hypolithic community, especially total nitrogen (TN) and soil organic carbon (SOC). However, the effect on taxonomic composition was greater than that on ecological function. The dominant bacterial phyla in all sample sites were Cyanobacteria, Actinobacteria, Proteobacteria, and Deinococcus-Thermus, but the abundances varied significantly between the sampling sites. The eastern site had the highest relative abundance of Proteobacteria (18.43%) and Bacteroidetes (6.32%), while the western site had a higher relative abundance in the phyla Cyanobacteria (62%) and Firmicutes (1.45%); the middle site had a higher relative abundance of Chloroflexi (8.02%) and Gemmatimonadetes (1.87%). The dominant phylum in the fungal community is Ascomycota. Pearson correlation analysis showed that the soil's physicochemical properties were also associated with changes in community diversity at the sample sites. These results have important implications for better understanding the community assembly and ecological adaptations of hypolithic microorganisms.

Seasonal Variation of Hypolithic Microbiomes in the Gobi Desert : Seasonal Variation of Hypolithic Microbiomes in the Gobi Desert.

Understanding how microbial communities adapt to environmental stresses is critical for interpreting ecological patterns and microbial diversity. In the case of the Gobi Desert, little is known on the environmental factors that explain hypolithic colonization under quartz stones. By analyzing nine hypolithic communities across an arid gradient and the effects of the season of the year in the Hexi Corridor of this desert, we found a significant decrease in hypolithic colonization rates (from 47.24 to 15.73%) with the increasing drought gradient and found two distinct communities in Hot and Cold samples, which survived or proliferated after a hot or a cold period. While Cold communities showed a greater species diversity and a predominance of Cyanobacteria, Hot communities showed a predominance of members of the Proteobacteria and the Firmicutes. In comparison, Cold communities also possessed stronger functions in the photosynthesis and carbon metabolism. Based on the findings of this study, we proposed that the hypolithic communities of the Hexi Corridor of the Gobi Desert might follow a seasonal developmental cycle in which temperature play an important role. Thus after a critical thermal threshold is crossed, heterotrophic microorganisms predominate in the hot period, while Cyanobacteria predominate in the cold period.

Temperature sensitivity of methanogenesis and anaerobic methane oxidation in thermokarst lakes modulated by surrounding vegetation on the Qinghai-Tibet Plateau.

Understanding the balance between methane (CH4) production (methanogenesis) and its oxidation is important for predicting carbon emissions from thermokarst lakes under global warming. However, the response of thermokarst lake methanogenesis and the anaerobic oxidation of methane (AOM) to warming, especially from Qinghai-Tibetan Plateau (QTP), is still not quantified. In this study, sediments were collected from 11 thermokarst lakes on the QTP. These lakes are surrounded with different vegetation types, including alpine desert (AD), alpine steppe (AS), alpine meadow (AM) and alpine swamp meadow (ASM). The results showed that methanogenesis and AOM rates exponentially increased with temperature, while the temperature sensitivity (Q10, average Q10 values of methanogenesis and AOM were 0.69-30 and 0.54-16.9 respectively) of methanogenesis were larger than AOM, but not significant, showing a similar temperature dependence of methanogenesis and AOM in thermokarst lake sediments. Thermokarst lake sediments in the ASM had higher methanogenesis and anaerobic oxidation potential, matching its higher NDVI and relative abundances of methanogens and SBM (syntrophic bacteria with methanogens). Although the thermokarst lake sediments AOM depleted 15 %-27.8 % of the total CH4 production, the AOM rate was lower than methanogenesis in thermokarst lake sediments, it did not offset increased CH4 production under anaerobic conditions. The increase in CH4 production in thermokarst lake sediments will likely lead to higher emissions within a warming world. These findings indicate that methanogenesis and AOM in thermokarst lake sediments are sensitive to climate change. Models should consider the Q10 values of methanogenesis and AOM and vegetation types when predicting carbon cycle in thermokarst lakes under global warming.

Genomic Investigation of Desert Streptomyces huasconensis D23 Reveals Its Environmental Adaptability and Antimicrobial Activity.

The harsh climatic conditions of deserts may lead to unique adaptations of microbes, which could serve as potential sources of new metabolites to cope with environmental stresses. However, the mechanisms governing the environmental adaptability and antimicrobial activity of desert Streptomyces remain inadequate, especially in extreme temperature differences, drought conditions, and strong radiation. Here, we isolated a Streptomyces strain from rocks in the Kumtagh Desert in Northwest China and tested its antibacterial activity, resistance to UV-C irradiation, and tolerance to hydrogen peroxide (H2O2). The whole-genome sequencing was carried out to study the mechanisms underlying physiological characteristics and ecological adaptation from a genomic perspective. This strain has a growth inhibitory effect against a variety of indicator bacteria, and the highest antibacterial activity recorded was against Bacillus cereus. Moreover, strain D23 can withstand UV-C irradiation up to 100 J/m2 (D10 = 80 J/m2) and tolerate stress up to 70 mM H2O2. The genome prediction of strain D23 revealed the mechanisms associated with its adaptation to extreme environmental and stressful conditions. In total, 33 biosynthetic gene clusters (BGCs) were predicted based on anti-SMASH. Gene annotation found that S. huasconensis D23 contains several genes and proteins associated with the biosynthesis of factors required to cope with environmental stress of temperature, UV radiation, and osmotic pressure. The results of this study provide information about the genome and BGCs of the strain S. huasconensis D23. The experimental results combined with the genome sequencing data show that antimicrobial activity and stress resistance of S. huasconensis D23 was due to the rich and diverse secondary metabolite production capacity and the induction of stress-responsive genes. The environmental adaptability and antimicrobial activity information presented here will be valuable for subsequent work regarding the isolation of bioactive compounds and provide insight into the ecological adaptation mechanism of microbes to extreme desert environments.

Inhibition of Angiogenesis by MiR-524-5p through Suppression of AKT and ERK Activation by Targeting CXCR7 in Colon Cancer Cells.

Increasing evidence shows that alterations in microRNA (miRNA) expression are involved in the occurrence and development of various malignant tumors, including colon cancer. MiRNA-524-5p has been reported to have anticancer activity in colon cancer. This study explored the influence of the miRNA-524-5p/CXCR7 axis on angiogenesis using colon cancer cells and further studied the mechanisms involved. We found that changing the expression of miRNA-524-5p can affect colonic proliferation, migration, and angiogenesis. Furthermore, angiogenesis induced by miRNA-524-5p overexpression was reversed by overexpression of CXCR7 in HT-29 cells, while the opposite was observed in Caco-2 cells. Furthermore, miRNA-524-5p inhibited the activation of AKT and ERK signaling by targeting CXCR7. Overall, our results indicated that the miRNA-524-5p/CXCR7 axis regulated angiogenesis in colon cancer cells through the AKT and ERK pathways.

Transcriptional and biochemical analyses of Planomicrobium strain AX6 from Qinghai-Tibetan Plateau, China, reveal hydrogen peroxide scavenging potential.

BACKGROUND: The bacterial mechanisms responsible for hydrogen peroxide (H2O2) scavenging have been well-reported, yet little is known about how bacteria isolated from cold-environments respond to H2O2 stress. Therefore, we investigated the transcriptional profiling of the Planomicrobium strain AX6 strain isolated from the cold-desert ecosystem in the Qaidam Basin, Qinghai-Tibet Plateau, China, in response to H2O2 stress aiming to uncover the molecular mechanisms associated with H2O2 scavenging potential. METHODS: We investigated the H2O2-scavenging potential of the bacterial Planomicrobium strain AX6 isolated from the cold-desert ecosystem in the Qaidam Basin, Qinghai-Tibet Plateau, China. Furthermore, we used high-throughput RNA-sequencing to unravel the molecular aspects associated with the H2O2 scavenging potential of the Planomicrobium strain AX6 isolate. RESULTS: In total, 3,427 differentially expressed genes (DEGs) were identified in Planomicrobium strain AX6 isolate in response to 4 h of H2O2 (1.5 mM) exposure. Besides, Kyoto Encyclopedia of Genes and Genomes pathway and Gene Ontology analyses revealed the down- and/or up-regulated pathways following H2O2 treatment. Our study not only identified the H2O2 scavenging capability of the strain nevertheless also a range of mechanisms to cope with the toxic effect of H2O2 through genes involved in oxidative stress response. Compared to control, several genes coding for antioxidant proteins, including glutathione peroxidase (GSH-Px), Coproporphyrinogen III oxidase, and superoxide dismutase (SOD), were relatively up-regulated in Planomicrobium strain AX6, when exposed to H2O2. CONCLUSIONS: Overall, the results suggest that the up-regulated genes responsible for antioxidant defense pathways serve as essential regulatory mechanisms for removing H2O2 in Planomicrobium strain AX6. The DEGs identified here could provide a competitive advantage for the existence of Planomicrobium strain AX6 in H2O2-polluted environments.

Temporary Survival Increasing the Diversity of Culturable Heterotrophic Bacteria in the Newly Exposed Moraine at a Glacier Snout.

Laohugou Glacier No. 12 is located on the northern slope of the western Qilian Mountains with a temperate continental wet climate and an extremely cold winter. Bacteria in a newly exposed moraine have to cope with various pressures owing to deglaciation at the glacier snout. However, limited information is available regarding the high diversity and temporary survival of culturable heterotrophic bacteria under various environmental stresses. To examine the tolerance of extremophiles against varying environmental conditions in a newly exposed moraine, we simulated environmental stress in bacterial cultures. The results showed that the isolated strains belonged to actinobacteria, Proteobacteria, Bacteroidetes, Deinococcus-Thermus, and Firmicutes. Actinobacteria was the most abundant phylum, followed by Proteobacteria, at both high and low temperatures. Pseudarthrobacter was the most abundant genus, accounting for 14.2% of the total isolates. Although several microorganisms grew at 10 °C, the proportion of microorganisms that grew at 25 °C was substantially higher. In particular, 50% of all bacterial isolates grew only at a high temperature (HT), whereas 21.4% of the isolates grew at a low temperature (LT), and 38.6% of the isolates grew at both HT and LT. In addition, many radiation-resistant extremophiles were identified, which adapted to both cold and oxidative conditions. The nearest neighbors of approximately >90% of bacteria belonged to a nonglacial environment, such as oil-contaminated soil, rocks, and black sand, instead of glacial niches. This study provides insights into the ecological traits, stress responses, and temporary survival of culturable heterotrophic bacteria in a newly exposed moraine with variable environmental conditions and the relationship of these communities with the non-glacial environment. This study may help to understand the evolution, competition, and selective growth of bacteria in the transition regions between glaciers and retreats in the context of glacier melting and retreat owing to global warming.

Ferroptosis: A novel therapeutic strategy and mechanism of action in glioma.

Glioma is the most common malignant tumor of the central nervous system and resistance is easily developed to chemotherapy drugs during the treatment process, resulting in high mortality and short survival in glioma patients. Novel therapeutic approaches are urgently needed to improve the therapeutic efficacy of chemotherapeutic drugs and to improve the prognosis of patients with glioma. Ferroptosis is a novel regulatory cell death mechanism that plays a key role in cancer, neurodegenerative diseases, and other diseases. Studies have found that ferroptosis-related regulators are closely related to the survival of patients with glioma, and induction of ferroptosis can improve glioma resistance to chemotherapy drugs. Therefore, induction of tumor cell ferroptosis may be an effective therapeutic strategy for glioma. This review summarizes the relevant mechanisms of ferroptosis, systematically summarizes the key role of ferroptosis in the treatment of glioma and outlines the relationship between ferroptosis-related ncRNAs and the progression of glioma.