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Climate change is rapidly transforming Arctic landscapes where increasing soil temperatures speed up permafrost thaw. This exposes large carbon stocks to microbial decomposition, possibly worsening climate change by releasing more greenhouse gases. Understanding how microbes break down soil carbon, especially under the anaerobic conditions of thawing permafrost, is important to determine future changes. Here, we studied the microbial community dynamics and soil carbon decomposition potential in permafrost and active layer soils under anaerobic laboratory conditions that simulated an Arctic summer thaw. The microbial and viral compositions in the samples were analyzed based on metagenomes, metagenome-assembled genomes, and metagenomic viral contigs (mVCs). Following the thawing of permafrost, there was a notable shift in microbial community structure, with fermentative Firmicutes and Bacteroidota taking over from Actinobacteria and Proteobacteria over the 60-day incubation period. The increase in iron and sulfate-reducing microbes had a significant role in limiting methane production from thawed permafrost, underscoring the competition within microbial communities. We explored the growth strategies of microbial communities and found that slow growth was the major strategy in both the active layer and permafrost. Our findings challenge the assumption that fast-growing microbes mainly respond to environmental changes like permafrost thaw. Instead, they indicate a common strategy of slow growth among microbial communities, likely due to the thermodynamic constraints of soil substrates and electron acceptors, and the need for microbes to adjust to post-thaw conditions. The mVCs harbored a wide range of auxiliary metabolic genes that may support cell protection from ice formation in virus-infected cells.ImportanceAs the Arctic warms, thawing permafrost unlocks carbon, potentially accelerating climate change by releasing greenhouse gases. Our research delves into the underlying biogeochemical processes likely mediated by the soil microbial community in response to the wet and anaerobic conditions, akin to an Arctic summer thaw. We observed a significant shift in the microbial community post-thaw, with fermentative bacteria like Firmicutes and Bacteroidota taking over and switching to different fermentation pathways. The dominance of iron and sulfate-reducing bacteria likely constrained methane production in the thawing permafrost. Slow-growing microbes outweighed fast-growing ones, even after thaw, upending the expectation that rapid microbial responses to dominate after permafrost thaws. This research highlights the nuanced and complex interactions within Arctic soil microbial communities and underscores the challenges in predicting microbial response to environmental change.

Objective To investigate the effects and potential mechanisms of osteoblast-derived exosomes on the biological properties of prostate cancer (PC) cells. Methods Human bone marrow mesenchymal stem cells was induced to differentiate into osteoblasts, and then the exosomes were extracted from the supernatant of cell culture medium by ultracentrifugation and identified. Clone formation assay was employed to determine the effect of derived exosomes on the proliferation of PC cells, and PCR microarray was used to analyze miRNA changes after exosome treatment. Fluorescence labeling was applied to validate the transfer of miRNA between osteoblasts and tumor cells. The impact of key miRNA on the biological characteristics of PC cells was studied at the cellular and animal levels. Bioinformatics analysis was conducted to explore the target genes of key miRNA and then further validated. Results Osteoblast-derived exosomes were successfully extracted and then identified. These exosomes significantly promoted the clonogenic ability of PC cells when compared with the cells without treatment (P < 0.05). PCR microarray showed that miR-223 might be a key molecule in this process. Membrane exchange experiments demonstrated the presence of membrane exchange between osteoblasts and PC cells, and miRNA FAM labeling displayed that miR-223 was transferred within above cells. Functional experiments indicated that overexpression of miR-223 enhanced the proliferation, anti-apoptosis, and migration/invasion ability of PC cells (P < 0.05). Bioinformatics analysis indicated that APC, an inhibitor of WNT signaling pathway, may be a target gene of miR-223, which was further confirmed that overexpressing miR-223 down-regulated APC expression. Rescue experiment showed that overexpression of APC reversed the promoting effect of miR-223 on the proliferation, migration and invasion of PC cells. Conclusion Osteoblast-derived exosomes are pro-carcinogenic factors in PC, and miR-223 may be a key molecule in exosomes, which plays a oncogenic role by regulating APC in PC cells.

Ability to directly sequence DNA from the environment permanently changed microbial ecology. Here, we review the new insights to microbial life gleaned from the applications of metagenomics, as well as the extensive set of analytical tools that facilitate exploration of diversity and function of complex microbial communities. While metagenomics is shaping our understanding of microbial functions in ecosystems via gene-centric and genome-centric methods, annotating functions, metagenome assembly and binning in heterogeneous samples remains challenging. Development of new analysis and sequencing platforms generating high-throughput long-read sequences and functional screening opportunities will aid in harnessing metagenomes to increase our understanding of microbial taxonomy, function, ecology, and evolution in the environment.

Cancer stem cells (CSCs) are involved in tumorigenesis, recurrence, and therapy resistance. To identify critical regulators of sarcoma CSCs, we performed a reporter-based genome-wide CRISPR-Cas9 screen and uncovered Kruppel-like factor 11 (KLF11) as top candidate. In vitro and in vivo functional annotation defined a negative role of KLF11 in CSCs. Mechanistically, KLF11 and YAP/TEAD bound to adjacent DNA sites along with direct interaction. KLF11 recruited SIN3A/HDAC to suppress the transcriptional output of YAP/TEAD, which, in turn, promoted KLF11 transcription, forming a negative feedback loop. However, in CSCs, this negative feedback was lost because of epigenetic silence of KLF11, causing sustained YAP activation. Low KLF11 was associated with poor prognosis and chemotherapy response in patients with sarcoma. Pharmacological activation of KLF11 by thiazolidinedione effectively restored chemotherapy response. Collectively, our study identifies KLF11 as a negative regulator in sarcoma CSCs and potential therapeutic target.

Crawler combine harvesters are mostly used in paddy field operation in South China. The field operation load is complex and variable, which leads to fatigue fracture and other accidents of gearboxes under the impact of variable loads and seriously affects the trouble-free working time of the whole machine. In order to solve the problem of high fault rate of gearboxes of crawler combine harvesters, the single HST hydro-mechanical differential steering gearbox developed by the team is taken as the test object, this study designs and builds the gearbox assembly fatigue test bench, and then carries out the fatigue test of differential steering gearboxes. The test results show that the test bench can well test the comprehensive working performance and durability of differential steering gearboxes, and has advantages of simple structure, convenient installation, etc. This is of great significance to study the fatigue damage rule of differential steering gearboxes, optimize and improve the mechanical structure of gearboxes and reduce the fault rate of its internal parts in the future.

Changes in labile carbon (LC) pools and microbial communities are the primary factors controlling soil heterotrophic respiration (Rh ) in warming experiments. Warming is expected to initially increase Rh but studies show this increase may not be continuous or sustained. Specifically, LC and soil microbiome have been shown to contribute to the effect of extended warming on Rh . However, their relative contribution is unclear and this gap in knowledge causes considerable uncertainty in the prediction of carbon cycle feedbacks to climate change. In this study, we used a two-step incubation approach to reveal the relative contribution of LC limitation and soil microbial community responses in attenuating the effect that extended warming has on Rh . Soil samples from three Tibetan ecosystems-an alpine meadow (AM), alpine steppe (AS), and desert steppe (DS)-were exposed to a temperature gradient of 5-25°C. After an initial incubation period, soils were processed in one of two methods: (a) soils were sterilized then inoculated with parent soil microbes to assess the LC limitation effects, while controlling for microbial community responses; or (b) soil microbes from the incubations were used to inoculate sterilized parent soils to assess the microbial community effects, while controlling for LC limitation. We found both LC limitation and microbial community responses led to significant declines in Rh by 37% and 30%, respectively, but their relative contributions were ecosystem specific. LC limitation alone caused a greater Rh decrease for DS soils than AMs or ASs. Our study demonstrates that soil carbon loss due to Rh in Tibetan alpine soils-especially in copiotrophic soils-will be weakened by microbial community responses under short-term warming.

Biochar is a soil amendment that has the potential to effectively improve soil salinization. However, there is a paucity of studies on sodium adsorption using biochar, and the adsorption mechanism remains unclear. To better understand the adsorption mechanism of Na+ on the surface of biochar, both pyrochar and hydrochar were produced at different temperatures. The capacity and influencing factors of Na+ adsorption in biochar were analyzed via batch adsorption experiments. Pore filling dominated the Na+ adsorption in the concentration of the NaCl solution when it was ≤100 mg/L, where wheat straw pyrochar (WB, 3.95–4.94 mg/g Na) and poplar wood chip pyrochar (PB, 0.62–0.70 mg/g Na) presented the release and adsorption of Na+, respectively. When the concentration of the NaCl solution was >100 mg/L, the adsorption capacity of WB (25.44–36.45 mg/g) was significantly higher than PB (4.46–6.23 mg/g). Both the adsorption and release of Na+ in hydrochar was insufficient. In a high concentration of NaCl solution, ion exchange became the key mechanism determining the adsorption of Na+ in pyrochar, in which K+ contributed to more than 94% of the Na+ adsorption. The findings proposed strategies for the structural design of biochar used for Na adsorption. These will promote the utilization of solid biowaste for sodium adsorption and the potential of soil salinization amendment for agriculture in arid lands. [ABSTRACT FROM AUTHOR]

Glomalin-related soil protein (GRSP) is an important component of soil organic carbon (SOC), which can promote long-term SOC sequestration. However, GRSP distribution characteristics and its contribution to the SOC pool among different grassland types remain poorly understood. Therefore, six grassland types (alpine meadow, mountain meadow, temperate meadow steppe, temperate steppe, temperate desert steppe, and temperate desert) were chosen to evaluate the contribution of GRSP to the SOC pool and the factors that influence GRSP accumulation in the Irtysh River Basin in China. The results revealed that GRSP (EE-GRSP, T-GRSP) accumulated more in the 0–10 cm soil layer than in the 10–20 cm soil layer (p < 0.05). GRSP content was higher in alpine grasslands (15.69 mg·g−1) than in desert grasslands (5.45 mg·g−1). However, their contribution to the SOC pool exhibited an opposite trend, whereas GRSP-C/SOC even accounted for 11.88% in the desert grasslands. The redundancy analysis (RDA) showed that SOC was the top important positive regulator for GRSP accumulation both in the two layers (explanatory rate > 80%). Besides the SOC factor, the two soil layers had different factors in regulating GRSP accumulation. Changes in GRSP content in the 0–10 cm soil layer were more strongly associated with mean annual temperature (MAT), sand content, soil water content (SWC), and silt content. In contrast, in the 10–20 cm soil layer, GRSP content was more influenced by SWC, electrical conductivity (EC), and pH (p < 0.05). Additionally, the main factor in the GRSP content variation was the interaction between climate and soil in the two soil layers (explanatory rate > 80%). Our findings underscore the critical role of GRSP in facilitating SOC sequestration within desert grasslands and elucidate the primary factors driving GRSP distribution across varying soil depths. [ABSTRACT FROM AUTHOR]