[Critical quality attribute assessment of big brand traditional Chinese medicine: quality control method of Huangjing Zanyu Capsules based on chemical properties of characteristic components].

The chemical properties of characteristic components are significant to the manufacturing quality control of big brand traditional Chinese medicine. In this study, the Huangjing Zanyu Capsules were used as the research carrier to determine the content of five characteristic components including icraiin, emodin, schisandrin A, 2,3,5,4'-tetrahydroxystilbene-2-O-ß-D-glucoside, and osthole simultaneously by high-performance liquid chromatography(HPLC). The results showed that the chemical properties of five cha-racteristic components had a good linear relationship(r>0.999 9) within the quantitative range; the relative standard deviations(RSD) was 0.11%-2.0% and 0.25%-2.8% respectively for intra-day and inter-day precision; the RSD of repeatability was 1.8%-2.6%; the RSD of stability within 48 hours was 0.19%-2.8%, and the average recovery rate was 95.52%-100.1%, all meeting the requirements of pharmaceutical quantitative analysis. Additionally, the interval estimation method was used to directly reflect the distribution of samples with abnormal chemical properties of characteristic components, and the results showed ten samples were detected beyound the 95% control line of confidence level. Multivariate statistical process control(MSPC) method was used to monitor the abnormal samples of Huangjing Zanyu Capsules collectively, and the results showed that two samples were beyond the 95% control line of Hotelling's T~2 and three samples beyond the 95% control line of squared prediction error(SPE), indicating consistent quality control of Huangjing Zanyu Capsules. In conclusion, the proposed method is not only accurate and efficient but also a compensation for the traditional single-component quality control method, providing a scientific basis for the quality control in manufacturing process of Huangjing Zanyu Capsules. Furthermore, it could also serve as a reference method for the quality control in manufacturing big brand traditional Chinese medicine.

Eupatilin Alleviates Lipopolysaccharide-Induced Acute Lung Injury by Inhibiting Inflammation and Oxidative Stress.

BACKGROUND Eupatilin, an active flavone separated from Artemisia species, has various biological activity such as anti-inflammatory activity. The aim of the present study was to find out the influence of eupatilin on lipopolysaccharide (LPS)-induced acute lung injury (ALI) in rats. MATERIAL AND METHODS The administration of LPS was used to induce ALI; eupatilin was given 1 hour before the LPS administration. Lung structural damage of rats was analyzed by hematoxylin and eosin staining and the wet/dry lung ratio. The related inflammatory factors and lung injury markers were examined by enzyme-linked immunosorbent assay. The oxidative stress factors were analyzed by corresponding kits. The expression of peroxisome proliferator-activated receptor-alpha (PPAR-alpha) was assayed by western blot and immunohistochemical staining. RESULTS The results showed that eupatilin alleviated LPS-induced structural damage and decreased the wet/dry lung ratio concentration-dependently. Eupatilin decreased the level of surfactant protein (SP)-A, SP-D, and inflammatory factors such as interleukin (IL)-6, tumor necrosis factor (TNF)-alpha, and monocyte chemo-attractant protein (MCP)-1. LPS trigged nitric oxide (NO) generation, improved the production of malondialdehyde (MDA) and lactate dehydrogenase (LDH) and decreased the activity of superoxide dismutase (SOD), which were reversed when rats treated with eupatilin in a concentration-dependent way. Besides, the expression of PPAR-a was increased under the treatment of eupatilin. CONCLUSIONS Collectively, eupatilin alleviated LPS-induced ALI through inhibiting inflammation and oxidative stress in a concentration-dependent way, which was likely to be closely related with the activation of PPAR-alpha.

Remediation effectiveness of vermicompost for a potentially toxic metal-contaminated tropical acidic soil in China.

Potentially toxic metal (PTM) contamination coupled with soil acidification has posed a severe threat to agricultural sustainability of tropical region in the world. In this study, a vermicopomst (VC) produced from vermicomposting cattle manure under tropical environment was applied to remediating a tropical acidic soil in Hainan, China. The effectiveness of VC in reducing available PTMs in soils was evaluated by incubation experiments with a Cd, Cr or Ni spiked soil and a Cd contaminated field soil. The dynamic changes of soil physical, chemical and biological properties after VC amendment were determined to understand the mechanisms of PTM immobilization. The results showed that VC amendment significantly reduced 0.01M CaCl2 extractable amounts of Cd, Ni and Cr in the spiked soils, and CaCl2 extractable Cd was reduced by 49.3% when VC was amended to the Cd contaminated field soil. Thermodynamic studies showed that VC had a high adsorption capacity for Cd, Ni and Cr, with the maximum adsorption (obtained from the Langmuir model) of 33.45, 26.17, and 20.88 mg/g, respectively. The reduction in CaCl2 extractable metals after VC amendment was consistent with the order of maximum adsorption of VC for Cd, Ni, and Cr. Vermicompost amendment increased soil pH by 0.7 to 1.5 units, which is positively related with VC rate, but negatively with the decrease in extractable metals. These results indicates that adsorption of metals onto VC and an increase in soil pH after VC amendment are likely responsible for the decreased availability of Cd, Ni, and Cr in the contaminated soil. In addition, the addition of stable organic substances and subsequent formation of water-stable aggregates may be also beneficial for immobilizing PTMs and improving tropical soil quality.

An analysis of the association between statin use and risk of endometrial and ovarian cancers in the Women's Health Initiative.

BACKGROUND: Statins have anti proliferative activity in vitro against endometrial and ovarian cancer and can affect levels of reproductive hormones. We analyzed data from the Women's Health Initiative (WHI) to assess whether statins are associated with risk of endometrial and ovarian cancer. METHODS: The WHI study included 161,808 postmenopausal women in which incident cases of endometrial (n = 1377) and ovarian cancer (n = 763) were identified over an average of 10.8 (SD + 3.3) years. Information on statin use and risk factors was collected at baseline and follow-up. Cox proportional hazards regression was used to calculate hazard ratios (HRs) with 95% confidence intervals (CIs) for the association of statin use and risk of endometrial and ovarian cancer. All statistical tests were two-sided. RESULTS: Statins were used at baseline by 7.5% women and by up to 25% at year nine. The multivariable adjusted HR for risk of endometrial cancer for baseline statin use was 0.74, 95% C.I. 0.59-0.94 and for ovarian cancer was 1.15, 95% C.I. 0.89-1.50. In time-dependent models, statins were not associated with endometrial cancer (HR 0.91, 95% C.I. 0.76-1.08) however there was an increased risk of ovarian cancer (HR 1.30, 95% CI 1.04-1.62), largely attributed to the effect of the hydrophilic statin, pravastatin (1.89, 95% CI 1.24-2.88). CONCLUSIONS: There was a reduction in risk of endometrial cancer among statin users at baseline but not in time-dependent models. Pravastatin use was associated with an increased risk of ovarian cancer. Analyses of larger numbers of cases are needed to evaluate these findings.

Interaction between Nonsteroidal Anti-inflammatory Drugs and Low-fat Dietary Intervention on Colorectal Cancer Incidence; the Women's Health Initiative (WHI) Dietary Modification Trial.

BACKGROUND: The Women's Health Initiative (WHI) Dietary Modification (DM) trial did not show that reductions in dietary fat accompanied by increases in vegetable and fruit consumption decrease the incidence of colorectal cancer. Secondary analyses suggested that aspirin use may modify the intervention effects of DM on colorectal cancer development, although a recent reanalysis including the postintervention period confirmed no main effect of the intervention on reducing colorectal cancer incidence Methods: We analyzed data from 48,834 postmenopausal women who were randomized into the low-fat DM (N = 19,540) or comparison (N = 29,294) group for an average 8.1 years and followed for an additional 9.4 years through August 31, 2014. Exposure to specific class(es) or strength(s) of nonsteroidal anti-inflammatory drugs (NSAIDs) was modeled at baseline and as time-dependent use through the 9-year clinic visit. A Cox proportional hazard model was employed to assess the association of the DM, medication use, and their interaction with colorectal cancer events. RESULTS: A total of 906 incident cases of colorectal cancer were identified during the intervention and postintervention periods. By both exposure models, we found that colorectal cancer incidence was not different in the DM from the comparison group among any type of NSAID users. None of the interactions with any category of NSAID use was statistically significant; however there was most modest evidence for an interaction (p = 0.07) with aspirin use at baseline (hazard ratio [HR] = 0.81, 95% confidence interval [CI], 0.60-1.11 for users; HR = 1.12, 95% CI, 0.97-1.30 for nonusers). Strength and duration of aspirin use at baseline did not alter the associations. CONCLUSION: Extended follow-up of women in the WHI DM trial did not confirm combined protective effects of aspirin and low-fat diet on colorectal cancer risk among the postmenopausal women.

Changes in physical activity, sedentary time, and risk of falling: The Women's Health Initiative Observational Study.

Falling significantly affects quality of life, morbidity, and mortality among older adults. We sought to evaluate the prospective association between sedentary time, physical activity, and falling among post-menopausal women aged 50-79years recruited to the Women's Health Initiative Observational Study between 1993 and 1998 from 40 clinical centers across the United States. Baseline (B) and change in each of the following were evaluated at year 3 (Y3) and year 6 (Y6; baseline n=93,676; Y3 n=76,598; Y6 n=75,428): recreational physical activity (MET-h/wk), sitting, sleeping (min/day), and lean body mass by dual energy X-ray absorptiometry (subset N=6475). Falls per year (0, 1, 2, ≥3) were assessed annually by self-report questionnaire and then dichotomized as ≤1 and ≥2falls/year. Logistic regression models were adjusted for demographics, body mass index, fall history, tobacco and alcohol use, medical conditions, and medications. Higher baseline activity was associated with greater risk of falling at Y6 (18%; p for trend <0.0001). Increasing sedentary time minimally decreased falling (1% Y3; 2% Y6; p<0.05). Increasing activity up to ≥9MET-h/wk. (OR: 1.12, 95% CI: 1.03-1.22) or maintaining ≥9MET-h/wk. (OR: 1.20, 95% CI: 1.13-1.29) increased falling at Y3 and Y6 (p for trend <0.001). Adding lean body mass to the models attenuated these relationships. Physically active lifestyles increased falling among post-menopausal women. Additional fall prevention strategies, such as balance and resistance training, should be evaluated to assist post-menopausal women in reaching or maintaining levels of aerobic activity known to prevent and manage several chronic diseases.

Prospective analysis of association between statins and pancreatic cancer risk in the Women's Health Initiative.

PURPOSE: To determine whether HMG-CoA reductase inhibitors (statins) are associated with a lower risk of pancreatic cancer. METHODS: The population included 160,578 postmenopausal women enrolled in the Women's Health Initiative (WHI) in which 385 incident cases of pancreatic cancer were identified over an average of 8.69 (SD ±4.59) years. All diagnoses were confirmed by medical record and pathology review. Information on statin use and other risk factors was collected at baseline and during follow-up. Multivariable-adjusted hazards ratios (HRs) and 95 % confidence intervals (CIs) evaluating the relationship between prior statin use (at baseline only as well as in a time-dependent manner) and risk of pancreatic cancer were computed from Cox proportional hazards regression analyses after adjusting for appropriate confounders. We also evaluated the effect of statin type, potency, lipophilic status, and duration of use. All statistical tests were two-sided. RESULTS: Statins were used at baseline by 12,243 (7.5 %) women. The annualized rate of pancreatic cancer in statin users and nonusers, respectively, was 0.0298 versus 0.0271 %. The multivariable-adjusted HR for statin users versus nonusers at baseline was 0.92 and 95 % CI 0.57-1.48. In a time-dependent model, the HR for low-potency statins was 0.46, 95 % CI 0.20-1.04. There was no significant effect seen by statin lipophilicity or duration of use. CONCLUSIONS: There was no significant relationship between statins and pancreatic cancer risk in the WHI; however, there was a marginal inverse association noted for low-potency statins. Analyses of larger numbers of cases are needed to further explore this relationship.

Growth and antioxidant production of Spirulina in different NaCl concentrations.

OBJECTIVE: To evaluate the quantity of Spirulina cultured in seawater, salt-tolerant strains were screened out and their growth and antioxidant accumulation were studied in different salt concentrations RESULTS: Salt tolerance of five Spirulina strains were investigated with modified Zarrouk medium (with 200-800 mM NaCl). All strains grew well with 400 mM NaCl; their growth rates were almost same as in the control medium. Spirulina strains FACHB-843 (SP843) and FACHB-972 (SP972) had the highest salt tolerance their growth rates in 600 mM NaCl were nearly same as the control. Both strains produced more carotene, phycocyanin, polysaccharides, proline and betaine in 400-600 mM NaCl than the control. Salt stress also induced them to produce higher activities of superoxide dismutase and peroxidase. Total antioxidant capacities of SP843 and SP972 peaked at 600 and 400 mM NaCl, respectively. CONCLUSION: Spirulina strains cultured with seawater accumulate more bioactive substances and will have a higher nutritive value.

Genome-wide association analysis of incident coronary heart disease (CHD) in African Americans: a short report.

African Americans have the highest rate of mortality due to coronary heart disease (CHD). Although multiple loci have been identified influencing CHD risk in European-Americans using a genome-wide association (GWAS) approach, no GWAS of incident CHD has been reported for African Americans. We performed a GWAS for incident CHD events collected during 19 years of follow-up in 2,905 African Americans from the Atherosclerosis Risk in Communities (ARIC) study. We identified a genome-wide significant SNP (rs1859023, MAF = 31%) located at 7q21 near the PFTK1 gene (HR = 0.57, 95% CI 0.46 to 0.69, p = 1.86×10(-08)), which replicated in an independent sample of over 8,000 African American women from the Women's Health Initiative (WHI) (HR = 0.81, 95% CI 0.70 to 0.93, p = 0.005). PFTK1 encodes a serine/threonine-protein kinase, PFTAIRE-1, that acts as a cyclin-dependent kinase regulating cell cycle progression and cell proliferation. This is the first finding of incident CHD locus identified by GWAS in African Americans.

Comamonas guangdongensis sp. nov., isolated from subterranean forest sediment, and emended description of the genus Comamonas.

A facultatively anaerobic bacterium, strain CY01(T), isolated from subterranean forest sediment collected from Guangdong Province, China, was investigated using a polyphasic taxonomic approach. The cells were short rods, Gram-negative, non-sporulating and motile. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain CY01(T) showed highest sequence similarities to Comamonas thiooxydans S23(T) (98.0 %), Comamonas testosteroni JCM 5832(T) (97.9 %), Comamonas koreensis KCTC 12005(T) (97.7 %) and Comamonas odontotermitis LMG 23579(T) (97.0 %). The major respiratory quinone was ubiquinone-8. The major cellular fatty acids were summed feature 3 (C16 : 1ω6c and/or C16 : 1ω7c), C16 : 0 and summed feature 8 (C18 : 1ω6c and/or C18 : 1ω7c). Based on the phylogenetic analysis, DNA-DNA hybridization, whole-cell fatty acid composition as well as biochemical characteristics, strain CY01(T) was clearly distinguishable from all recognized species of the genus Comamonas and should be classified as a representative of a novel species of the genus, for which the name Comamonas guangdongensis sp. nov. is proposed. The type strain is CY01(T) ( = CCTCC AB 2011133(T) = KACC 16241(T)).

Occurrence, distribution, and driving factors of current-use pesticides in commonly cultivated crops and their potential risks to non-target organisms: A case study in Hainan, China.

Multiple pesticides are heavily applied in crops grown in China's tropics due to the prevalence of diseases and pests, thus posing potential risks to nontarget organisms (e.g., honeybees, lacewings, ladybugs, and humans). However, there is little information on this topic. This study is the first assessment of the occurrence, driving factors, and ecological/human health risks of 32 current-use pesticides (CUPs) in 10 frequently-planted crops collected from practicing rice-vegetable rotation systems in Hainan, China. Of the 132 whole crop samples, 44 (33.3 %) residues from ≥8 pesticides were detected in 9.09 % of crop samples with concentrations ≥0.5 mg kg-1. Six pesticide residues, namely carbendazim, pyraclostrobin, acetamiprid, thiophanate methyl, phoxim, and imidacloprid, were detected in 72.7 % of samples, with concentrations ranging from 0.0021 to 13.5 (median = 0.032) mg kg-1. Among them, carbendazim, pyraclostrobin, and acetamiprid were the most common, contributions from 10.2 to 25.5 % and a detection frequency ranging from 25.6 to 56.1 %. The order of total concentration of 32 CUPs (∑32 CUP) concentrations during the year was January > May > November > August and vegetables > rice, being highly related with pesticides usage pattern, crop type, plant accumulation/dissipation and plant lipid contents. The ecological risk quotients (RQs) to four beneficial terrestrial organisms showed that 9.6-39.1 % of samples posed a potential medium or high ecological risk, with 13.6-65.9 % of samples at ∑RQ > 1 being highly affected by the residues of neonicotinoids and emamectin benzoate. Emamectin benzoate (8.9 %) and acetamiprid (5.6 %) exceeded the individual Maximum Residue Levels based on Chinese legislation (GB2763-2021). Moreover, cumulative dietary exposure presented a higher risk to humans in 11.0 and 22.0 % of the cases for acute and chronic, mainly originating from the higher concentration contributors of systemic pesticides in edible crops. Therefore, the regulation and monitoring of CUP residues is imperative for rice-vegetable rotation systems in tropical China to avoid negative effects on nontarget organisms.

Occurrence and ecological risks of flonicamid and its metabolites in multiple substrates from intensive rice-vegetable rotations in tropical China.

Rice-vegetable rotations are dominant in (sub)-tropical agriculture worldwide. However, fate and risks of the insecticide flonicamid (FLO) and its main degradates (collectively called FLOMs) in multiple substrates from those cropping systems remain largely unknown. In this study, we characterized residual concentrations, driving factors, transport, and potential ecological risks of FLOMs in different substrates in 28 tropical rice-vegetable rotations. Concentrations (median) of FLOMs were 0.013-3.03 (0.42) ng g-1 in plants, 0.012-1.92 (0.23) ng g-1 in soil, 0.029-0.63 (0.126) µg L-1 in water, and 0.002-0.398 (0.055) ng g-1 in sediments. Flonicamid and its metabolite N-(4-trifluoromethylnicotinoyl) glycine were the dominant species in the four substrates (84.1 % to 88.5 %). Plants had the highest levels of FLOMs, with the highest bioconcentration factor in peppers. According to boosted regression trees coupled with a partial least squares structural equation model, levels and composition of FLOMs showed high spatiotemporal and crop-related patterns in different substrates, with patterns highly codetermined by agricultural practices (e.g., crop type and FLO/neonicotinoid/pyrethroid applications), substrate parameters (e.g., pH, organic matter or total organic carbon), and climate features (e.g., wet/dry seasons). Moreover, a fugacity method indicated differences in transport and partitioning patterns in different substrates during rice and vegetable planting periods. Integrated substrate risk assessment of FLOMs contamination was conducted based on species-sensitive distributions and substrate weight index. Although overall risks of FLOM contamination in tropical rice-vegetable rotations were negligible to low, the highest risks were in soils, vegetable planting periods, and a central intensively planted area.

Neonicotinoids in draining micro-watersheds dominated by rice-vegetable rotations in tropical China: Multimedia occurrence, influencing factors, transport, and associated ecological risks.

Multimedia contamination by neonicotinoid (NEO) residues has attracted global attention. However, data regarding the multimedia polluted status under certain typical cropping scenarios and the associated risks are scarce. Here, the multimedia occurrence, spatiotemporal distribution, driving factors, transport, and ecological risks of NEOs from tropical rice-vegetable rotation fields were characterized. The heavy NEOs resided in multiple media, and imidacloprid and acetamiprid were the prevailing NEOs, with concentration contributions of 65-80%. The pollution levels of the NEOs, rather than their compositions, exhibited significant spatiotemporal heterogeneity and were highly correlated with the collective (agricultural practices and climate conditions) and differential (e.g., media properties) factors identified using an auto linear regression model. Furthermore, the multimedia transport of NEOs was largely similar but non-negligibly different during the rainy and dry seasons. A new multimedia ecological risk assessment revealed that 50.6% sites were at high risk, and the risk hotspots occurred in the central areas and the winter planting period. The risks were largely contributed by imidacloprid and thiamethoxam, indicating that there were non-ignorable ecological risks. Our results highlight the differential pollution patterns (distribution, transport, and driving factors) of the prevailing NEOs under tropical agricultural scenarios, and the fact that special attention should be paid to the risks posed by NEOs.

Aversive conditioning information transmission in Drosophila.

Animals rapidly acquire surrounding information to perform the appropriate behavior. Although social learning is more efficient and accessible than self-learning for animals, the detailed regulatory mechanism of social learning remains unknown, mainly because of the complicated information transfer between animals, especially for aversive conditioning information transmission. The current study revealed that, during social learning, the neural circuit in observer flies used to process acquired aversive conditioning information from demonstrator flies differs from the circuit used for self-learned classic aversive conditioning. This aversive information transfer is species dependent. Solitary flies cannot learn this information through social learning, suggesting that this ability is not an innate behavior. Neurons used to process and execute avoidance behavior to escape from electrically shocked flies are all in the same brain region, indicating that the fly brain has a common center for integrating external stimuli with internal states to generate flight behavior.

Novel discovery of schisandrin A regulating the interplay of autophagy and apoptosis in oligoasthenospermia by targeting SCF/c-kit and TRPV1 via biosensors.

Oligoasthenospermia is the primary cause of infertility. However, there are still enormous challenges in the screening of critical candidates and targets of oligoasthenospermia owing to its complex mechanism. In this study, stem cell factor (SCF), c-kit, and transient receptor potential vanilloid 1 (TRPV1) biosensors were successfully established and applied to studying apoptosis and autophagy mechanisms. Interestingly, the detection limit reached 2.787 × 10-15 g/L, and the quantitative limit reached 1.0 × 10-13 g/L. Furthermore, biosensors were used to investigate the interplay between autophagy and apoptosis. Schisandrin A is an excellent candidate to form a system with c-kit similar to SCF/c-kit with a detection constant (KD) of 5.701 × 10-11 mol/L, whereas it had no affinity for SCF. In addition, it also inhibited autophagy in oligoasthenospermia through antagonizing TRPV1 with a KD of up to 4.181 × 10-10 mol/L. In addition, in vivo and in vitro experiments were highly consistent with the biosensor. In summary, high-potency schisandrin A and two potential targets were identified, through which schisandrin A could reverse the apoptosis caused by excessive autophagy during oligoasthenospermia. Our study provides promising insights into the discovery of effective compounds and potential targets via a well-established in vitro-in vivo strategy.

Forgotten memory storage and retrieval in Drosophila.

Inaccessibility of stored memory in ensemble cells through the forgetting process causes animals to be unable to respond to natural recalling cues. While accumulating evidence has demonstrated that reactivating memory-stored cells can switch cells from an inaccessible state to an accessible form and lead to recall of previously learned information, the underlying cellular and molecular mechanisms remain elusive. The current study used Drosophila as a model to demonstrate that the memory of one-trial aversive olfactory conditioning, although inaccessible within a few hours after learning, is stored in KCαß and retrievable after mild retraining. One-trial aversive conditioning triggers protein synthesis to form a long-lasting cellular memory trace, approximately 20 days, via creb in KCαß, and a transient cellular memory trace, approximately one day, via orb in MBON-α3. PPL1-α3 negatively regulates forgotten one-trial conditioning memory retrieval. The current study demonstrated that KCαß, PPL1-α3, and MBON-α3 collaboratively regulate the formation of forgotten one-cycle aversive conditioning memory formation and retrieval.

Polycyclic aromatic hydrocarbons (PAHs) in surface soils of tropical reef islands in China under external plant and soil introduction: Occurrence, sources, risks, and relationships with soil properties, vegetation cover, and soil source.

This study explored the levels, sources, and risks of PAHs in soils from Yongle Atoll (YLA) and Xuande Atoll (XDA) of the Xisha Islands (XSIs) in the South China Sea, China, under different vegetation cover types and soil sources. The results clearly showed that the levels of 16 US EPA priority PAHs (Σ16PAHs) are relatively low in XDA and YLA, with concentrations ranging from not detected (ND) to 151 ng/g (average 15.7 ng/g) and ND to 5.8 ng/g (average 2.1 ng/g), respectively. Three- and four-ring PAHs (62.3% and 53.8%) were widely distributed in YLA and XDA. The average concentration of Σ16PAHs in soils with shrub cover was 1.4, 1.8, 4.8, and 5.0 times higher than that in soils with herbaceous cover, vegetable cover, arbor cover, and no plant cover, respectively. Source analysis using binary diagnostic ratios and the positive matrix factorization (PMF) model suggested that PAHs have similar sources (gasoline/coal combustion, coke production, and biomass combustion), but different contributions in native soil and introduced soil. Moreover, diesel-related vehicular emission was identified to be an additional source of PAHs in native soil. Pearson's correlations revealed strong relationships between PAHs and organic matter or total organic carbon. The cancer risk of PAHs varied among different vegetation cover types and soil sources, following the orders herbaceous cover > vegetable cover > shrub cover > arbor cover > no plant cover and introduced soil > mixed soil > native soil. Nevertheless, the risk remained lower than the risk threshold (10-6), suggesting low carcinogenesis risk in the two atolls. Our findings provide new evidence for the introduction of external vegetation/soil acting as a driver of changes in the characteristics of PAHs in islands, and also underline the negligibility of the PAH increase in soils in the South China Sea, China, from the perspective of health hazards.

Molecular linkages between chemodiversity and MCPA complexation behavior of dissolved organic matter in paddy soil: Effects of land conversion.

Complexation of dissolved organic matter (DOM) plays a crucial role in regulating the fate and risk of agrochemicals. Here, taking a toxic herbicide MCPA (4-chloro-2- methylphenoxyacetic acid) as the target, the effect of land conversion on complexation behavior of DOM to agrochemicals was investigated in paddy soil. Furthermore, the mechanisms were explored in a new perspective of DOM chemodiversity. Soil DOMs were selected from four long-term cropping systems, including paddy field (PF), vegetable field (VF), rice-vegetable rotation (RV) and abandoned land (AL). The results showed that the DOMs in PF and AL were rich in hydrophilic substances (e.g., carbohydrates or protein-like molecules) with low aromaticity. However, after converting PF to VF and RV, abundant aromatic macromolecules and aliphatic alkanes were observed in DOM. Due to those changes in DOM chemodiversity, the binding site and capability of DOM were highest in VF and RV, and were positively correlated with DOM aromaticity, MW, humus and polar groups (e.g., amino). This was because the complexation of "DOM-MCPA" was static binding via ligand exchange and H-bonding among polar groups and hydrophobic interaction among aromatic skeletons. The EEM-PARAFAC confirmed that microbial humic-like substances dominated the complexation of DOM rather than terrestrial humic-like and tryptophan-like matters. The 2D-COS analysis further revealed that the complexation of DOM preferentially occurred in amino, polysaccharide C-O and aliphatic C-H for PF and AL, but in aromatic C=C, amide C=N for RV and VF. In summary, these findings provide molecular insight into the effect of land conversion on DOM complexation activity, which highlight the importance of DOM chemodiversity. These results will contribute to the risk assessments of agrochemicals in paddy soil.

Corynebacterium humireducens sp. nov., an alkaliphilic, humic acid-reducing bacterium isolated from a microbial fuel cell.

A novel halotolerant, alkaliphilic, humic acid-reducing bacterium, designated MFC-5(T), was isolated from a microbial fuel cell that was fed continuously with artificial wastewater (pH 10.0). Cells were Gram-positive-staining, facultatively anaerobic, non-fermentative, non-motile rods and had a G+C content of 59.0 mol%. Microbial growth was observed with <13 % (w/v) NaCl (optimum 10 %), at pH 7.0-11.0 (optimum pH 9.0) and at 25-45 °C (optimum 37 °C). Strain MFC-5(T) was active in the anaerobic reduction of a humic acid analogue, anthraquinone-2,6-disulphonate, with lactate, formate, acetate, ethanol or sucrose as the electron donor. The major cellular fatty acids were C(18 : 1)ω9c (42.68 %), C(16 : 0) (33.69 %), C(18 : 0) (7.56 %), C(17 : 1)ω8c (5.14 %) and C(17 : 0) (3.39 %). Phylogenetic analysis demonstrated that strain MFC-5(T) displayed >3 % 16S rRNA gene sequence divergence from its closest relatives. Based on phenotypic, genetic and phylogenetic analysis, a novel species, Corynebacterium humireducens sp. nov., is proposed. The type strain is MFC-5(T) ( = NBRC 106098(T)  = CGMCC 2452(T)  = DSM 45392(T)).

Pesticides in surface waters of tropical river basins draining areas with rice-vegetable rotations in Hainan, China: Occurrence, relation to environmental factors, and risk assessment.

Pesticides are heavily applied in rice-vegetable rotations in tropical China, yet publicly available information on the contamination and risk of currently used pesticides (CUPs) and legacy pesticides (LPs) in surface waters of river basins draining these areas is very limited. Therefore, in two tropical river basins (Nandu River and Wanquan River basins) dominated by rice-vegetable rotations in Hainan, China, pesticides were analyzed in 256 surface water samples in wet and dry seasons. Forty-one pesticides were detected, and total concentrations ranged from not detectable to 24.2 µg/L. Carbendazim and imidacloprid were the two most prevalent CUPs, detected in 59.8% and 17.7%, respectively, of surface water samples at concentrations above 0.1 µg/L. Chlorpyrifos was the main LP, detected in 9.0% of samples at a concentration above 0.05 µg/L. The fungicides difenoconazole and emamectin benzoate, the herbicide butachlor, and the insecticide acetamiprid occurred in ≥12.5% samples at concentrations above 0.1 µg/L. Surface waters typically (85.2%) contained 5 to 15 residues, with an average of nine. Seasonally, the concentrations of the 41 pesticides were in the order January > July > November > September. Spatially, the composition of the main CUPs (not LPs) was significantly different depending on position in the drainage, which also changed with seasons. Crop and pest types and wet and dry seasons were the key factors controlling the spatiotemporal distribution of CUPs and LPs in surface waters. On the basis of evaluations of the exposures to individual pesticides and the dominant combinations with ≥8 pesticides, multiple pesticides were likely a significant risk to aquatic organisms, although noncarcinogenic and carcinogenic risks to humans were low. This study provides valuable data to better understand pesticide occurrence and ecological risks in river basins draining areas with rice-vegetable rotation systems in tropical China.