The single and combined effects of sulfamethazine and cadmium on soil nitrification and ammonia-oxidizing microorganisms.

The coexistence of antibiotics and heavy metals in soil has attracted increasing attention due to their negative effects on microorganisms. However, how antibiotics and heavy metals affect functional microorganisms related to nitrogen cycle remains unclear. The goals of this work were to explore the individual and combined effects of sulfamethazine (SMT) and cadmium (Cd), selected as target pollutants in soil, on potential nitrification rates (PNR) and ammonia oxidizers (ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB)) structure and diversity by 56-day cultivation experiment. Results showed that PNR in Cd- or SMT-treated soil decreased at the beginning of the experiment and then increased over time. PNR was significantly correlated with AOA and AOB-amoA relative abundance (P < 0.01). SMT addition (10 and 100 mg kg-1) significantly improved AOA activity by 13.93% and 17.93%, respectively, and had no effect on AOB at day 1. Conversely, Cd at 10 mg kg-1 significantly inhibited AOA and AOB by 34.34% and 37.39%, respectively. Moreover, the relative abundance of AOA and AOB in combined SMT and Cd addition clearly higher relative to single Cd at 1 day. The single and combined Cd and SMT increased and reduced the community richness of AOA and AOB, respectively, but reduced the diversity of both after 56 days. Cd and SMT treatments significantly changed the relative abundance of AOA phylum levels and AOB genus levels in the soil. It was mainly manifested in reducing the relative abundance of AOA Thaumarchaeota, and increasing the relative abundance of AOB Nitrosospira. Besides, AOB Nitrosospira was more tolerant to the compound addition of both than single application.

Microbial nutrient limitations limit carbon sequestration but promote nitrogen and phosphorus cycling: A case study in an agroecosystem with long-term straw return.

Soil fertility can be increased by returning crop residues to fields due to the cooperative regulation of microbial metabolism of carbon (C) and nutrients. However, the dose-effect of straw on the soil C and nutrient retention and its underlying coupled microbial metabolic processes of C and nutrients remain poorly understood. Here, we conducted a comprehensive study on soil nutrients and stoichiometry, crop nutrient uptake and production, microbial metabolic characteristics and functional attributes using a long-term straw input field experiment. We estimated the microbial metabolic limitations and efficiency of C and nitrogen (N) use (CUE and NUE) via an enzyme-based vector-TER model, biogeochemical-equilibrium model and mass balance equation, respectively. In addition, the absolute abundances of 20 functional genes involved in the N- and P-cycles were quantified by quantitative PCR-based chip technology. As expected, straw input significantly increased C and N stocks, C: nutrients, crop nutrient uptake and growth. However, the C sequestration efficiency decreased by approximately 6.1 %, and the N2O emission rate increased by 0.5-1.0 times with the increase in straw input rate. Interestingly, the microbial metabolism was more limited by P when straw input was <8 t ha-1 but was reversed when straw input was 12 t ha-1. The enhanced nutrient limitation reduced both the CUE and the NUE of microbes and then upregulated genes associated with the hydrolysis of C, the mineralization of N and P, and denitrification, which consequently influenced C and N losses as well as crop growth. This study highlights that soil C and nutrient cycling are strongly regulated by microbial metabolic limitation, suggesting that adding the appropriate limiting nutrients to reduce nutrient imbalances caused by straw input is conducive to maximizing the ecological benefits of straw return.

Toxicological effects of single and joint sulfamethazine and cadmium stress in soil on pakchoi (Brassica chinensis L.).

The combined pollution of heavy metals and antibiotics in soil has attracted increasing attention due to their negative effects on plant growth. The aims of this study were to evaluate the phytotoxicity of single and combined sulfamethazine (SMT) and cadmium (Cd), selected as target pollutants in soil, on growth and physiological response of pakchoi (Brassica chinensis L.). Results revealed that the soil spiked with 10 mg kg-1 Cd inhibited the pakchoi growth regardless of SMT addition. The combined effect of SMT and Cd stress on uptake of SMT or Cd by pakchoi were concerned with their combined concentration. The combined influence of high concentrations SMT and Cd (1 and 10 mg kg-1) exposure on the Cd content of pakchoi showed antagonistic effects and synergistic effects, respectively. Besides, oxidative substances and enzyme activity of pakchoi tissue were affected by Cd and SMT exposure in the soil, particularly by their joint stress. This mainly expressed as the increase of malondialdehyde (MDA), H2O2 content and antioxidant enzyme activity (superoxide dismutase (SOD), peroxidase (POD), catalase (CAT)), which could be ascribed to the induction of Cd and SMT stress. Additionally, the SMT-Cd combined stress caused more reduction in nutrients (vitamin C and sugar) of pakchoi than the correspondingly single Cd stress. In conclusion, the SMT and Cd in soil lead to their accumulation and oxidative damage in pakchoi, which disturb the antioxidant defense system and ultimately adversely affect growth and quality of pakchoi.

The Control Strategies for Information Asymmetry Problems Among Investing Institutions, Investors, and Entrepreneurs in Venture Capital.

To analyze the problem of information asymmetry between investment institutions, investors, and entrepreneurs, thereby protecting the interests of all parties and ensuring the income under high risks, some companies listed on Shanghai Stock Exchange and Shenzhen Stock Exchange are taken as research samples. First, the relations between investment institutions, investors, and entrepreneurs, as well as the causes and solutions of information asymmetry in venture capital, are analyzed. Second, based on the residual model, a model that analyzes the information asymmetry and investment efficiency of the enterprise is built. Finally, through two cases, the relation between the information asymmetry and the investment rate is revealed. The research results show that from 2014 to 2018, the investment level of companies listed on the Shanghai Stock Exchange and Shenzhen Stock Exchange was below 7.69%; the investment levels of different companies varied greatly, with significant differences in the development situations. Besides, information asymmetry is significantly related to investment efficiency. The corresponding regression coefficient is 0.0119. The larger the enterprise is, the higher the investment efficiency will be. The case analysis shows that it is important to understand and seize the market, and the information asymmetry between the actual environment and the investment environment is more serious. To deal with these issues, material incentives, reputation incentives, control incentives, and stock option incentives are substantive measures that can be taken, which are of great significance for improving the decision-making level of investors and investment institutions and reducing the investment risk of investors and entrepreneurs.

Experimental supporting data on seasonal dynamics of different soil nitrogen pools affected by long-term fertilization regimes.

The data presented in this article are related to the research paper entitled "Changes in N supply pathways under different long-term fertilization regimes in Northeast China" [1]. Seasonal dynamics of soil NH4 +-N, NO3 --N, soil microbial biomass nitrogen (N) and fixed NH4 + were provided on the basis of a 26-year long-term experiment, including six treatments: no fertilizer (CK), recycled manure (M), N and P fertilizers (NP), P and K fertilizers (PK), N, P and K fertilizers (NPK), and NPK fertilizers with recycled manure (NPKM). The presentation of potential N retention and supply through soil microbial biomass N and fixed NH4 + pools at different growth stages is helpful for comparing the effects of different N pools on soil N transformation and assessing synchronies between crop N demand and soil N supply through different N pools.

Evaluation of Different Types and Amounts of Amendments on Soil Cd Immobilization and its Uptake to Wheat.

Using amendments is a cost-effective method to soil cadmium (Cd) remediation, whereas knowledge about how different amendments and rates affect remediation efficiency remains limited. This study aimed to evaluate the impacts of different types and amounts of amendments on soil Cd immobilization and its uptake by plants. Biochar (BC), zeolite (ZE), humic acid (HA), superphosphate (SP), lime (L), and sodium sulfide (SS) were applied at three rates (low, medium, and high) ranging from 0.5 to 5%. The concentration of CaCl2-extractable Cd was considerably affected by the amendments, except HA, and the high doses achieved better immobilization effects than the low doses did. The addition of amendments decreased weak acid soluble Cd by 4.1-44.0% but slightly increased the fractions of oxidizable and residual Cd. These amendments (except BC and HA dose of 1%) decreased Cd accumulation in grains by 1.3-68.8% and (except SP) in roots by 16.3-65.5% compared with the control. The SP efficiently immobilized Cd but posed a potential soil acidification risk. Moreover, SS treatment increased the soil electrical conductivity (EC) value and restricted the growth of wheat, possibly due to high-salt stress. BC, ZE, and L exerted significant effects on the reduction in available Cd as the application rate increased. These amendments enhanced Cd immobilization mainly by changing Cd availability in soil and influencing its redistribution in different fractions in soil and root uptake by plants. This study concluded that BC-5%, ZE-1%, and L-0.5% can be used for Cd immobilization in acidic or neutral soils.

Effect of luteolin on apoptosis, MAPK and JNK signaling pathways in guinea pig chondrocyte with osteoarthritis.

Osteoarthritis (OA) is a degenerative joint disease usually seen in the elderly, which incidence increases with age. Its pathogenesis and underlying mechanism are still unclear. The disease severely affects the physical health and life quality of patients, thereby constituting a huge economic burden to family and society. Luteolin (LUT) is a natural flavonoid with multiple pharmacological properties. Many plants containing LUT have been applied in the treatment of several inflammation-related diseases due the relatively strong anti-inflammatory effects of LUT. The present study investigated the influence of LUT on cell apoptosis and inflammatory reactions in cartilage of OA guinea pigs, and its underlying mechanism. It was found that LUT effectively inhibited proliferation of OA cartilage cells, down-regulated the expressions of JNK and p38MAPK in cartilage cells of OA, and downregulated NO, TNF-α and IL-6. Thus, it alleviated inflammatory reactions, protected cartilage cells, and delayed cartilage degeneration.

The hsa-miR-181a-5p reduces oxidation resistance by controlling SECISBP2 in osteoarthritis.

BACKGROUND: The phenotypes of osteoarthritis (OA) consist of cartilage extracellular matrix (ECM) metabolism disorder and the breakdown of cartilage homeostasis, which are induced by pro-inflammatory factors and oxidative stress. Selenoproteins regulated by selenocysteine insertion sequence binding protein 2 (SBP2) are highly effective antioxidants, but their regulatory mechanisms, particularly the involvement of miRNAs, are not fully understood. METHODS: To explore whether miR-181a-5p and SBP2 are involved in OA pathogenesis, we established an IL-1ß model using the chondrocyte SW1353 cell line. Next, we up- or down-regulated SBP2 and miRNA-181a-5p expression in the cells. Finally, we measured the expression of miRNA-181a-5p, SBP2 and three selenoproteins in OA cartilage and peripheral blood. RESULTS: The results showed that IL-1ß increased hsa-miR-181a-5p and decreased SBP2 in a time- and dose-dependent manner. GPX1 and GPX4, which encode crucial glutathione peroxidase antioxidant enzymes, were up-regulated along with SBP2 and miR-181a-5p. Furthermore, SBP2 showed a significant negative correlation with miR-181a-5p during induced ATDC5 cell differentiation. There was lower GPX1 and GPX4 mRNA expression and SBP2 protein expression in damaged cartilage than in smooth cartilage from the same OA sample, and hsa-miR-181a-5p expression on the contrary. Similar results were observed in peripheral blood. In conclusion, we have reported a novel pathway in which pro-inflammatory factors, miRNA, SBP2 and selenoproteins are associated with oxidation resistance in cartilage. CONCLUSION: Overall, this study provides the first comprehensive evidence that pro-inflammatory factors cause changes in the cartilage antioxidant network and describes the discovery of novel mediators of cartilage oxidative stress and OA pathophysiology. Our data suggest that miR-181a-5p may be used to develop novel early-stage diagnostic and therapeutic strategies for OA.