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Free-living diazotrophs play a critical role in nitrogen (N) supply to ecosystems. Land-use change and plant rhizosphere are two important factors influencing diazotroph populations, but their relative strength in determining the soil diazotrophic community is still unclear, especially in acidic soils. One natural vegetation (the dominant species is green foxtail) and three agricultural land-uses (maize, peanut and soybean, respectively) widely distributed in the acidic soil region of southern China were selected. Bulk and rhizosphere soils were collected from every land-use, and their properties were determined. Quantitative PCR and high-throughput sequencing were applied to investigate soil diazotrophic abundance, diversity and community composition. Land use conversion from natural vegetation to different agricultural land-uses significantly reduced diazotroph abundances in bulk soils, however, the rhizosphere had a positive effect on the abundances in agricultural land-uses. Statistical analysis showed that the rhizosphere exerted a stronger effect on diazotroph abundance than land-use change. Converting natural vegetation to agricultural land-uses also decreased diazotroph richness and land-use types differed significantly in community composition, but plant rhizosphere did not cause these effects. In particular, the community variations in leguminous plants were more distinct than maize. Land-use change also influenced some topological properties of the community network. In acidic soil, land-use change has noticeable effects on the richness and composition of diazotrophic community than the rhizosphere. The rhizosphere, however, has a more obvious effect in increasing the abundance of the diazotrophs. These results highlight the critical role of land-use change in manipulating soil diazotrophic community composition.

The anti-tumor activity of ginsenosides has been widely explored, however, there is very little research on the anti-inflammatory potency of Ginkgo biloba L. leaves cyclopeptides (GBLCs). In the current study, four novel GBLCs were isolated and their amino acid sequence was determined. Herein, we found that GBLCs alleviated benzo(a)pyrene (BaP)-induced inflammation in human umbilical vein endothelial cells (HUVECs). Interestingly, GBLC-4 [Cyclo-(Leu-Phe-Ile-his)] significantly attenuated the BaP-induced reactive oxygen species generation and mitochondrial membrane potential collapse in HUVECs. Furthermore, GBLC-4 attenuated the expression of intercellular adhesion molecule-1 and vascular cell adhesion molecule-1, and blocked NF-κB pathway activation to mitigate the injuries caused by BaP. Notably, we provide a novel mechanism, suggesting that GBLCs may be potential agents for vascular inflammatory disease therapy.

Although phosphorus (P) availability and plant cultivation affect diazotrophic populations, studies often consider individual factors rather than their combined effects. Their relative importance to diazotrophs remains poorly understood, especially in acidic soils with P deficiency. It is hypothesized that the influences of P fertilization and plant cultivation on diazotrophic communities differ in acidic soils. The objectives were to investigate these influences and identify the key determining factors. Maize was grown in an acidic soil that was supplemented with 0, 20, and 50 mg P kg− 1 for 42 days. Maize biomasses, plant nutrient contents, and soil physicochemical properties were determined. Based on the nifH gene, the abundances and community compositions of diazotrophs in the different plant/soil compartments (bulk soils, rhizosphere soils, and roots) were respectively investigated using quantitative PCR and high-throughput sequencing. P fertilization significantly improved the diazotrophic abundances in the bulk and rhizosphere soils, but not in the roots. The plant/soil compartments had stronger effects on the abundance and diversity of diazotrophs than did P fertilization. Furthermore, the plant/soil compartments influenced diazotrophic community composition, but P fertilization did not. However, in the same sampling site, P fertilization caused community variations in the bulk and rhizosphere soils, rather than in the roots. Although P fertilization affected the abundances and compositions of diazotrophic communities in the bulk and rhizosphere soils, the plant/soil compartments resulting from maize cultivation had more noticeable effects than did P fertilization. These findings improved the understanding of biological nitrogen fixation in acidic soils.

In vitro production of oocytes capable of producing offspring has exciting potential applications in reproductive medicine. Here, we generated and characterized an ovarian organoid model derived from female germline stem cells using a three-dimensional culture system. We show that this model generated normal offspring and detected drug toxicity. The ovarian organoids could produce oocytes and exhibited endocrine functions. Single-cell analysis of ovarian organoids identified six ovarian cell lineages, such as germ, granulosa and theca cells, and produced gene-expression signatures for each cell type. Investigation of the expression patterns of genes related to meiosis and gene ontogeny analysis for germ cell clusters showed that a germ cell population was maintained in the ovarian organoids. Moreover, flow cytometric analysis confirmed that the population of germ cells could be maintained on the organoids and showed that ascorbic acid treatment had a beneficial effect of germ cell population maintenance on the organoids. Furthermore, we demonstrated the successful production of offspring from oocytes derived from ovarian organoids. Finally, we showed the ovarian organoids had the potential to drug toxicological detection. For example, we found that salinomycin impaired the formation of ovarian organoids and germ cell population maintenance by inducing apoptosis. These results indicate that the female germline stem cell-derived ovarian organoids represent a valuable model system for generating oocytes that can yield offspring, and provide a novel model for drug screening and toxicological detection.

Scorpion venom represents a significant source of bio-active peptides. However, the anti-inflammatory potency of scorpion venom oligopeptides (CMOs) has not been well explored. In the current study, thirty-five CMOs were isolated, the amino acid sequences were identified, and the anti-inflammatory potency was further explored in lipopolysaccharide (LPS)-induced RAW264.7 macrophages. The results showed that CMO-1 (His-Tyr-Gly-His) demonstrated the best anti-inflammatory potency by attenuating inflammatory cytokine (NO, TNF-α, IL-6, and IL-1β) production. CMO-1 also inhibited IκBα degradation and p65 nuclear translocation and suppressed NF-κB activation. Moreover, CMO-1 inhibited the phosphorylation of ERK, JNK, and p38 MAPKs. It is worth noting that CMO-1 exhibited anti-inflammatory potency; thus, it is a potential anti-inflammatory agent.

Myocardial fibrosis plays a central role in the development of heart failure. It has been shown that recurrent exposure to subclinical lipopolysaccharide (LPS) increases mortality and induces cardiac fibrosis in mice, which is not mediated by the common renin-angiotensin system. LPS increased NADPH oxidase2 (NOX2) in isolated adult mouse cardiac fibroblasts and NOX2 may mediate LPS-induced cardiac fibrosis. Therefore, the current study was designed to delineate the role of NOX2 in LPS-induced fibrosis model and to investigate the preventive role of Tanshinone IIA (TIIA) on the development of cardiac fibrosis. The protective mechanism of TIIA was determined to be associated with the inhibition of NOX2, by comparing its effects with the NADPH oxidase inhibitor, apocynin. The results revealed remarkable effects of apocynin and TIIA on attenuating the development of myocardial fibrosis and fibrosis-related genes and mediators. Furthermore, TIIA and apocynin decreased the expression of NADPH oxidase subunits (NOX2 and P67phox) expression and the ROS levels. The anti-fibrotic effect of apocynin suggested that NOX2 inhibition may be a potential preventive strategy for attenuating the progression of LPS-induced cardiac fibrosis. Our results demonstrate that TIIA may be a potent agent against subclinical LPS-induced cardiac fibrosis in mice partially via inhibition of NADPH oxidase 2.

Phosphorus (P) deficiency is an important factor that limits the agricultural production potential in acidic soils. The bacterial phoC gene encodes non-specific acid phosphatase (ACP), which participates in the mineralization of soil organic P and is therefore important for the improvement of soil P availability. However, the function and community population of phoC-harboring bacteria and their driving factors in acidic soil remain largely unknown. For this study, 51 soil samples and 207 plant samples were collected from four locations in the acidic soil region of southern China. Quantitative PCR and high-throughput sequencing were employed to analyze abundance and community composition of phoC-harboring bacteria. The results showed that soil P availability was the important nutrient element limiting the growth of both plants and soil bacteria. Soil ACP activity was clearly higher than alkaline phosphatase, indicating the important effect of phoC-harboring bacteria in acidic soils. ACP activity and phoC gene abundance showed a significant positive correlation, and both were closely related to soil available P, total carbon, and total nitrogen. The dominant genera of phoC-harboring bacteria involved Cupriavidus, Stenotrophomonas, and Xanthomonas. Compared to land-use pattern, sampling location, and soil parent material, soil property played a more important role in affecting phoC-harboring bacterial community structure, where N-related variables including soil NO 3 - -N, NH 4 + -N, and C/N ratio appeared to be the main factors. These findings suggest that phoC-harboring bacteria should provide an important contribution to soil P availability in acidic soil, and its function and community composition were strongly associated with soil nutrients.

Acid and alkaline phosphatase (ACP and ALP), encoded separately by the bacterial phoC and phoD genes, participate in the mineralization of organic phosphorus (P) to inorganic P. However, the influence of chemical fertilization on soil phosphatase activities and associated bacterial communities in acidic soils remains unclear. Here, we conducted a 27 year continuous chemical fertilization experiment consisting of the no-fertilizer control (CK), N and P fertilizer (NP), N and K fertilizer (NK), P and K fertilizer (PK), and N, P and K fertilizer (NPK) treatments, in order to investigate phosphatase activities and phoC- and phoD-harboring bacterial communities. Results demonstrated that ACP and ALP activities increased significantly in the NP (198.70 and 35.46 μg pNP g−1 soil h−1, respectively) and NPK treatments (199.62 and 36.51 μg pNP g−1 soil h−1, respectively) compared to CK (143.81 and 22.49 μg pNP g−1 soil h−1, respectively), while ALP activity was reduced for the NK treatment (13.86 μg pNP g−1 soil h−1). The abundance and diversity index of phoC- and phoD-harboring bacteria differed among treatments. The two bacterial community structures exhibited similar trends in terms of the significant differences between N-free (CK and PK) and N-containing (NP, NK and NPK) treatments (Adonis, p

Low soil nutrient availability severely constrains plant growth and productivity in acidic soil ecosystems. Diazotrophs and arbuscular mycorrhizal fungi (AMF) are the important microbial groups that improve the bioavailability of soil nitrogen (N) and phosphorus (P), respectively. Therefore, the objective was to investigate the biogeographic patterns and co-occurrence networks of the diazotrophic and AMF communities in the acidic soil ecosystem. We collected 52 soil samples from four long-term field observation stations with spatial distances of 961.3 km in the acidic soil region of southern China, and analyzed the community composition and biogeographic distributions of the diazotrophs and AMF using high-throughput sequencing of the functional gene amplicons. The variation partition analysis indicated that soil physicochemical factors provided more contributions than geographic distance, sampling stations and land-use types in the assembly of the diazotrophic and AMF community communities. Distance-decay relationships and Mantel tests showed that soil physicochemical factors had remarkable effects on both microbial community structures, whereas geographic distance only significantly affected the diazotrophic community variations. Co-occurrence network analysis revealed that AMF network was more complex and stable than the diazotrophic network. Furthermore, the dominant genera Bradyrhizbium and Glomus might be the more important keystone taxa in the diazotrophic and AMF networks, respectively. These findings suggest that the diazotrophic and AMF communities exhibit different assembly mechanisms and co-occurrence ecological networks in the acidic soil region of southern China, and both community assemblies were mainly driven by soil physicochemical factors.

The nitrogen (N) cycle process in agricultural soil is affected by fertilization. However, there is limited information on the abundance of N-cycling microbial community and its response to the different fertilization strategies in acidic soil. Using quantitative PCR, we investigated the microbial abundance involving 11 functional genes of the N cycle (nifH, chiA, aprA, archaeal and bacterial amoA, napA, narG, nirS, nirK, norB and nosZ) in an acidic agricultural soil. The soils were subjected to no fertilizer (Control), chemical NPK fertilizer (NPK), NPK combined with quicklime (NPKCa), NPK combined with crop residues (NPKS), NPK combined with quicklime and crop residues (NPKSCa), NPK combined with manure (NPKM) and only manure (M) fertilization for 27 years. Results showed that fertilization improved crop yield and soil nutrient availability, changed soil pH levels and affected the abundance of N-cycling functional genes. Manure application markedly increased the abundance of all genes and was associated with the largest shift in community structure. The variation of microbial community in the fertilization treatments (NPK, NPKCa, NPKS, NPKSCa, M and NPKM) resulted from the distinct contribution of functional genes, in which the nifH, napA and archaeal amoA genes highly contributed to the community variations between manure fertilization and Control. Soil variables, particularly pH, NO3−-N and AP, significantly affected the N-cycling microbial community structure. Overall, the different fertilization strategies demonstrated varying influential patterns on the N-cycling microbial abundance and community by altering soil properties and affecting specific functional gene abundance; in particular, manure treatments had a greater influence compared to chemical fertilizers.

Cardiac dysfunction is a critical event during sepsis/septic shock. Tanshinone IIA (TIIA), a compound extracted from herb medicine Danshen, has been shown possessing anti-inflammatory and anti-oxidative properties. It is possible, therefore, that treatment with TIIA may attenuate cardiac dysfunction during sepsis/septic shock through inhibition of inflammation. To test this possibility, we preadministrated C57BL/6 mice with TIIA prior to lipopolysaccharide (LPS) challenge. LPS significantly suppressed left ventricular function as evidenced by decreases in EF% and FS% in mice. However, TIIA pretreatment significantly attenuated cardiac dysfunction following LPS challenge. Furthermore, TIIA markedly attenuated the LPS-induced upregulation of circulating tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) levels. Meanwhile, LPS challenge significantly increased myocardial reactive oxygen species (ROS) production, which was attenuated by TIIA. Moreover, TIIA treatment dramatically decreased the level of the Nox2, reduced phosphorylation levels of extracellular signal-regulated kinase 1/2 (ERK1/2) and p38 mitogen-activated protein kinase (p38 MAPK) expression. In conclusion, TIIA effectively improves cardiac function during endotoxemia in mice. This is attributed to TIIA reducing inflammatory cytokines release and inhibiting the Nox2 signaling during endotoxemia.

Chlorophyll content, photosystem 2 functioning (Fv/Fm, Fv/F0), activity of ribulose-1,5-bisphosphate carboxylase/oxygenase, and net photosynthetic rates (PN) of flag leaf blade, sheath, peduncle, and ear organs were assessed in large-ear type (Pin 7) and small-ear type (ND93) wheat cultivars. Some differences were found in photosynthetic properties between different green plant parts, the values of all studied parameters in ear parts being higher in Pin7 than in ND93. Furthermore, ear surface areas and ear PN in 26 wheat genotypes measured at anthesis showed highly significant positive correlation with grain mass per ear. Hence a greater capability of ear photosynthesis may result in a greater grain yield in large-ear type cultivars.