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Microbial volatile compounds alter the soil microbial community 全文
2017
Yuan, Jun | Zhao, Mengli | Li, Rong | Huang, Qiwei | Raza, Waseem | Rensing, Christopher | Shen, Qirong
Volatile organic compounds (VOCs) from soil bacteria are likely to have an important role in the interactions among soil microorganisms. However, their effects on the soil microbial community have not been extensively studied. In this study, the effect of bacterial VOCs generated by growing Bacillus amyloliquefaciens NJN-6 on modified MS medium on soil microbial community was evaluated. B. amyloliquefaciens NJN-6 was able to produce 48 volatile compounds as determined by solid-phase microextraction-GC/MS. MiSeq sequencing data showed that bacterial VOCs could alter the composition of both soil bacterial and soil fungal communities and could decrease the alpha-diversity of the soil microbial community. Taxonomic analysis revealed that bacterial VOCs significantly increased the relative abundance of Proteobacteria, Bacteroidetes, and Firmicutes. Moreover, bacterial VOCs significantly increased the relative abundance of Ascomycota. The qPCR data showed that bacterial VOCs of strain NJN-6 decreased the soil fungal biomass and increased the soil bacterial biomass. Further evaluation of the effect of bacterial VOCs on functional genes revealed that VOCs could reduce the copies of nifH, nirS, and a gene encoding nonribosomal peptide synthase, while increasing the copy number of the ammonium-oxidizing bacteria gene. The effect on gene encoding polyketide synthase was insignificant. Results from this study indicated that bacterial VOCs could influence the soil microbial community as well as functional gene abundance.
显示更多 [+] 显示较少 [-]Transport and transformation of mercury during wet flue gas cleaning process of nonferrous metal smelting 全文
2017
Liu, Zhilou | Wang, Dongli | Peng, Bing | Chai, Liyuan | Liu, Hui | Yang, Shu | Yang, Bentao | Xiang, Kaisong | Liu, Cao
Reducing mercury emission is hot topic for international society. The first step for controlling mercury in fuel gas is to investigate mercury distribution and during the flue gas treatment process. The mercury transport and transformation in wet flue gas cleaning process of nonferrous smelting industry was studied in the paper with critical important parameters, such as the solution temperature, Hg⁰ concentration, SO₂ concentration, and Hg²⁺ concentration at the laboratory scale. The mass ratio of the mercury distribution in the solution, flue gas, sludge, and acid fog from the simulated flue gas containing Hg²⁺ and Hg⁰ was 49.12~65.54, 18.34~35.42, 11.89~14.47, and 1.74~3.54%, respectively. The primary mercury species in the flue gas and acid fog were gaseous Hg⁰ and dissolved Hg²⁺. The mercury species in the cleaning solution were dissolved Hg²⁺ and colloidal mercury, which accounted for 56.56 and 7.34% of the total mercury, respectively. Various mercury compounds, including Hg₂Cl₂, HgS, HgCl₂, HgSO₄, and HgO, existed in the sludge. These results for mercury distribution and speciation are highly useful in understanding mercury transport and transformation during the wet flue gas cleaning process. This research is conducive for controlling mercury emissions from nonferrous smelting flue gas and by-products.
显示更多 [+] 显示较少 [-]Coffee, its roasted form, and their residues cause birth failure and shorten lifespan in dengue vectors 全文
2017
Dieng, Hamady | Ellias, Salbiah Binti | Satho, Tomomitsu | Abu Hassan Ahmad, | Fatimah Abang, | Ghani, Idris Abd | Noor, Sabina | Ahmad, Hamdan | Zuharah, Wan Fatma | Morales Vargas, Ronald E. | Morales, Noppawan P. | Hipolito, Cirilo N. | Attrapadung, Siriluck | Noweg, Gabriel T. (Gabriel Tonga)
In dengue mosquitoes, successful embryonic development and long lifespan are key determinants for the persistence of both virus and vector. Therefore, targeting the egg stage and vector lifespan would be expected to have greater impacts than larvicides or adulticides, both strategies that have lost effectiveness due to the development of resistance. Therefore, there is now a pressing need to find novel chemical means of vector control. Coffee contains many chemicals, and its waste, which has become a growing environmental concern, is as rich in toxicants as the green coffee beans; these chemicals do not have a history of resistance in insects, but some are lost in the roasting process. We examined whether exposure to coffee during embryonic development could alter larval eclosion and lifespan of dengue vectors. A series of bioassays with different coffee forms and their residues indicated that larval eclosion responses of Aedes albopictus and Ae. aegypti were appreciably lower when embryonic maturation occurred in environments containing coffee, especially roasted coffee crude extract (RCC). In addition, the lifespan of adults derived from eggs that hatched successfully in a coffee milieu was reduced, but this effect was less pronounced with roasted and green coffee extracts (RCU and GCU, respectively). Taken together, these findings suggested that coffee and its residues have embryocidal activities with impacts that are carried over onto the adult lifespan of dengue vectors. These effects may significantly reduce the vectorial capacity of these insects. Reutilizing coffee waste in vector control may also represent a realistic solution to the issues associated with its pollution.
显示更多 [+] 显示较少 [-]Temperature drop and the risk of asthma: a systematic review and meta-analysis 全文
2017
Cong, Xiaowei | Xu, Xijin | Zhang, Yuling | Wang, Qihua | Xu, Long | Huo, Xia
The relationship between asthma and temperature changes remains controversial. The aim of this study was to investigate the association between temperature changes and the risk of asthma. A total of 26 studies (combined total number of subjects N > 26 million), covering 13 countries and Costa Rica, were identified by using a series of keywords in different combinations and searching the papers in PubMed, EMBSEA, Web of Science, MEDLINE, AIM, LILACS, and WPRIM before February 2016. Most of the papers were published in English. Random-effects meta-analyses were performed to evaluate the effect of temperature drop on risk of asthma. Several secondary analyses were also calculated based on stratification for different age, season, latitude, and region on risk of asthma. The odds ratio (OR) estimate between temperature drop and asthma was 1.05 (95% CI 1.02, 1.08) in the meta-analysis. For children, the overall OR was 1.09 (95% CI 1.03, 1.15). Dose-effect analyses showed stronger associations in asthma risk for each 1°1 °C decrement in short-term temperature (OR 1.055, 95% CI 1.00, 1.11). Further stratifications showed that winter (OR 1.03, 95% CI 1.01, 105) and low latitude (OR 1.72, 95% CI 1.23, 2.41) have a statistically significant association with the increased risk of asthma. Exposure of people to short-term temperature drop (per 1 °C decrement) was significantly associated with the risk of lower respiratory tract infections (LRTI) with asthma (OR 1.02, 95% CI 1.00, 1.04). Results suggest an adverse effect of temperature drop on asthma risk, especially in children and low-latitude areas. It may be opportune to consider the preventive actions against temperature drop, including simple face masks, to decrease the risk of asthma.
显示更多 [+] 显示较少 [-]Characterisation and risk assessment of polycyclic aromatic hydrocarbons (PAHs) in soils and plants around e-waste dismantling sites in southern China 全文
2017
Wang, Yujie | He, Jiexin | Wang, Shaorui | Luo, Chunling | Yin, Hua | Zhang, Gan
Environmental pollution due to primitive e-waste dismantling activities has been intensively investigated over the last decade in the south-eastern coastal region of China. In the present study, we investigated the distribution and composition of polycyclic aromatic hydrocarbons (PAHs) in soils and plants around e-waste recycling sites in Longtang, Guangdong province, South China. The results indicated that PAH concentrations in rhizosphere soil and non-rhizosphere soil were in the range of 133 to 626 ng/g and 60 to 816 ng/g, respectively, while PAH levels in plant tissue were 96 to 388 ng/g in shoots and 143 to 605 ng/g in roots. PAHs were enriched in rhizosphere soils in comparison with non-rhizosphere soils. The concentrations of PAHs in plant tissues varied greatly among plant cultivars, indicating that the uptake of PAHs by plants is species-dependent. Different profiles of PAHs in the soil and the corresponding plant tissue implied that PAH uptake and translocation by plants were selective.The total daily intakes of PAHs and carcinogenic PAHs through vegetables at the e-waste recycling site were estimated to be 99 and 22 ng/kg/day, respectively, suggesting that potential health risks associated with the consumption of contaminated vegetables should not be ignored.
显示更多 [+] 显示较少 [-]Nitrogen fertility and abiotic stresses management in cotton crop: a review 全文
2017
Khan, Aziz | Tan, Daniel Kean Yuen | Afridi, Muhammad Zahir | Luo, Honghai | Tung, Shahbaz Atta | Ajab, Mir | Shah, Fahad
This review outlines nitrogen (N) responses in crop production and potential management decisions to ameliorate abiotic stresses for better crop production. N is a primary constituent of the nucleotides and proteins that are essential for life. Production and application of N fertilizers consume huge amounts of energy, and excess is detrimental to the environment. Therefore, increasing plant N use efficiency (NUE) is important for the development of sustainable agriculture. NUE has a key role in crop yield and can be enhanced by controlling loss of fertilizers by application of humic acid and natural polymers (hydrogels), having high water-holding capacity which can improve plant performance under field conditions. Abiotic stresses such as waterlogging, drought, heat, and salinity are the major limitations for successful crop production. Therefore, integrated management approaches such as addition of aminoethoxyvinylglycine (AVG), the film antitranspirant (di-1-p-menthene and pinolene) nutrients, hydrogels, and phytohormones may provide novel approaches to improve plant tolerance against abiotic stress-induced damage. Moreover, for plant breeders and molecular biologists, it is a challenge to develop cotton cultivars that can tolerate plant abiotic stresses while having high potential NUE for the future.
显示更多 [+] 显示较少 [-]Decreased total antioxidant capacity has a larger effect size than increased oxidant levels in urine in individuals with autism spectrum disorder 全文
2017
Yui, Kunio | Tanuma, Nasoyuki | Yamada, Hiroshi | Kawasaki, Yohei
Oxidant/antioxidant imbalance may contribute to the pathophysiology of autism spectrum disorder (ASD). We assayed urinary levels of oxidative stress related biomarkers, hexanoyl-lysine (HEL), total antioxidant capacity (TAOC), the DNA methylation biomarker 8-hydroxy-2′-deoxyguanosine (8-OHdG), and plasma levels of superoxide dismutase (SOD), which is major antioxidant enzyme. We examined the relationship between these four biomarkers and social responsiveness in 20 individuals with ASD and in 11 healthy controls. The sex (ASD group, 7/13 vs. control group, 4/7) and age distributions (ASD group, 10.7 ± 5.0 years vs. control group, 14.7 ± 6.3 years) were not significantly different between the groups. Social responsiveness was assessed using the social responsiveness scale (SRS). We used standardized regression coefficients to measure the effect size. The ASD group exhibited significantly lower urinary TAOC levels and significantly elevated urinary HEL levels than the control group. Urinary 8-OHdG levels and plasma SOD levels were not significantly different between the groups. The ASD group showed significantly higher SRS scores than the control group. Plasma SOD levels correlated significantly with urinary TAOC levels. Standardized regression coefficients revealed that TAOC levels had a larger effect size than HEL levels in urine. This study firstly reveals that an imbalance between urinary HEL and TAOC levels in favor of urinary TAOC levels may contribute to impaired social responsiveness in individuals with ASD. Plasma SOD levels may also affect urinary TAOC levels.
显示更多 [+] 显示较少 [-]Oxidative stress and early DNA damage in workers exposed to iron-rich metal fumes 全文
2017
Pandeh, Masoud | Fathi, Saedeh | Zare Sakhvidi, Mohammad Javad | Zavar Reza, Javad | Sedghian, Lyla
Occupational exposure to metal fumes occurs routinely in many occupational settings. The inflammatory response to fumes and metals after exposure could lead to an increase in reactive oxygen species and level of DNA damage. In this study, the level of early DNA damage and oxidative stress was evaluated in a group of steel company (n = 30) and compared to the non-exposed (n = 28) subjects. All DNA damage markers in workers were significantly higher in exposed group in comparison with controls (p < 0.001). Stratified analysis based on smoking showed no significant differences between smoking and comet assay parameters. There was no significant difference between workers and controls in terms of HCT, TIBC, iron, and ferreting. However, HB in controls was significantly lower than exposed group (p < 0.001). A significant increase in catalase activity and MDA serum levels were observed in workers in comparison with controls. These findings suggest for the potential genotoxic effect of iron reach dust. Due to recent findings on the predictive potential of comet assay for cancer development, further, researches should be conducted to investigate the possible biochemical mechanism of such finding.
显示更多 [+] 显示较少 [-]Excellent performance of cobalt-impregnated activated carbon in peroxymonosulfate activation for acid orange 7 oxidation 全文
2017
Huang, Tianyin | Chen, Jiabin | Wang, Zhongming | Guo, Xin | Crittenden, John C.
Cobalt-impregnated activated carbon (GAC/Co) was used to produce sulfate radical (SO₄ ·⁻) from peroxymonosulfate (PMS) in aqueous solution (hereafter called PMS activation). We evaluated its effectiveness by examining the degradation of orange acid 7 (AO7). GAC/Co exhibited high activity to activate PMS to degrade AO7. The degradation efficiency of AO7 increased with increasing dosage of GAC/Co or PMS and elevated temperatures. pH 8 was most favorable for the degradation of AO7 by GAC/Co-activated PMS. The radical quenching experiments indicated that the reactions most likely took place both in the bulk solution and on the surface of GAC/Co. We found that SO₄ ·⁻ played a dominant role in AO7 degradation. Sodium chloride (NaCl) which presents in most dye wastewater had a significant impact on AO7 degradation. Low dosages (<0.4 M) of NaCl showed a slight inhibitory effect, whereas high dosages (0.8 M) increased the reaction rate. HOCl was confirmed as the main contributor for accelerating AO7 degradation with high concentration of NaCl. In a continuous-flow reaction with an empty-bed contact time of 1.35 min, AO7 was not detected in the effluent for 0 to 18.72 L of treated influent volume (156 h) and 85% removal efficiency was still observed after 40.32 L of treated volume (336 h). Finally, the azo bond and the naphthalene structure in AO7 were destroyed and the degradation pathway was proposed.
显示更多 [+] 显示较少 [-]Responses of growth, malformation, and thyroid hormone-dependent genes expression in Bufo gargarizans embryos following chronic exposure to Pb2+ 全文
2017
Chai, Lihong | Li, Yanbin | Chen, Zhihong | Chen, Aixia | Deng, Hongzhang
The aim of this study was to examine the adverse effects of lead (Pb) exposure on Bufo gargarizans embryos. The 96 h-LC₅₀ of Pb²⁺ for B. gargarizans embryos was determined to be 26.6 mg L⁻¹ after an acute test. In the chronic test, B. gargarizans embryos at Gosner stage 3 were exposed to 10~2000 μg Pb²⁺ L⁻¹ during embryogenesis. Total length, weight, developmental stage, and malformation were monitored. In addition, the transcript levels of type II and type III iodothyronine deiodinase (Dio2 and Dio3) and thyroid hormone receptors (TRα and TRβ) were determined to assess the thyroid-disrupting effects of Pb²⁺. Slightly increased growth and development of B. gargarizans embryos were observed at low concentrations of Pb²⁺ (10, 50, and 100 μg L⁻¹), while retarded growth and development were found at high concentrations of Pb²⁺ (1000 and 2000 μg L⁻¹). In addition, Pb²⁺ exposure induced morphological abnormalities, which were characterized by edema at tail, wavy fin, abdominal edema, stunted growth, hyperplasia, and axial flexures in B. gargarizans embryos. Furthermore, our results showed that exposure to 2000 μg Pb²⁺ L⁻¹ decreased the transcript levels of Dio2, TRα, and TRβ, but it increased Dio3 mRNA level. In contrast, exposure to 50 μg Pb²⁺ L⁻¹ increased TRα mRNA level and decreased Dio3 mRNA level. These results suggested that Pb²⁺ might have thyroid-disrupting effects, leading to the disruption of growth and development in B. gargarizans embryos.
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