环境浓度下磺胺混合物对秀丽线虫(Caenorhabditis elegans)生长、饮食、抗氧化酶及其调控基因表达水平的影响

磺胺类药物在环境中的普遍残留引起了人们对其潜在效应的担忧。因为磺胺混合物的效应不能通过单个物质效应进行准确预测,所以需要针对混合物效应开展深入研究。将秀丽线虫暴露于4种常用磺胺药物(磺胺嘧啶、磺胺吡啶、磺胺甲噁唑和磺胺甲嘧啶)组成的、环境浓度水平(0.01 mg·L-1)的混合物后,对生长调控基因dbl-1和egl-4,饮食调控基因eat-2和eat-18,过氧化氢酶(CAT)编码基因ctl-2和ctl-3,寿命调控基因sir-2,以及凋亡调控基因ced-4的表达水平进行检测。暴露组与空白对照组的结果比较表明,秀丽线虫dbl-1表达水平没有显著变化(下调3%),egl-4表达下调18%,解释了生长的抑制效应(抑制率为15.6%)。eat-2和eat-18的表达水平下调幅度相似,介于20%~22%之间,该幅度高于饮食的抑制效应(10.7%)。ctl-2和ctl-3的表达水平上调,分别比空白对照组高101%与66%,该幅度显著小于0.01 mg·L-1磺胺混合物暴露对CAT活性的刺激效应(比空白对照组高789.5%)。此外,sir-2的表达水平没有显著变化,与线虫寿命没有受到显著影响相一致。同时,ced-4表达上调32%,预示凋亡水平的显著增加。egl-4、eat-2、ctl-2和ced-4基因表达水平的显著变化分别表明磺胺混合物对β转化生长因子(TGF-β),烟酰乙酰胆碱受体(n AChR)、抗氧化系统以及细胞凋亡等多个方面的产生影响。     

聚丙烯基改性纤维固相萃取水中的苯酚

通过高能电子束辐照的方法,在聚丙烯（PP）纤维基体上分别接枝长链丙烯酸十八酯（SA）和亲水性丙烯酸-β-羟乙酯（HEA）2种单体,并将该纤维作为固相萃取填料,用于固相萃取（SPE）水中的痕量苯酚。研究了SPE过程中上样速度、洗脱溶剂、洗脱体积以及洗脱速度等因素对纤维萃取效果的影响。结果表明,改性纤维对痕量苯酚的富集倍数达95~145倍,回收率达到90%~98%,甲醇对纤维有良好的再生效果,纤维重复使用6次以内时,吸附性能无明显变化。     

Antibiotic removal from water: Elimination of amoxicillin and ampicillin by microscale and nanoscale iron particles

Zerovalent iron powder (ZVI or Fe⁰) and nanoparticulate ZVI (nZVI or nFe⁰) are proposed as cost-effective materials for the removal of aqueous antibiotics. Results showed complete removal of Amoxicillin (AMX) and Ampicillin (AMP) upon contact with Fe⁰ and nFe⁰. Antibiotics removal was attributed to three different mechanisms: (i) a rapid rupture of the β-lactam ring (reduction), (ii) an adsorption of AMX and AMP onto iron corrosion products and (iii) sequestration of AMX and AMP in the matrix of precipitating iron hydroxides (co-precipitation with iron corrosion products). Kinetic studies demonstrated that AMP and AMX (20 mg L⁻¹) undergo first-order decay with half-lives of about 60.3 ± 3.1 and 43.5 ± 2.1 min respectively after contact with ZVI under oxic conditions. In contrast, reactions under anoxic conditions demonstrated better degradation with t_1/2 of about 11.5 ± 0.6 and 11.2 ± 0.6 min for AMP and AMX respectively. NaCl additions accelerated Fe⁰ consumption, shortening the service life of Fe⁰ treatment systems.     

Impact of soil management practices on yield,fruit quality,and antioxidant contents of pepper at four stages of fruit development

Peppers, a significant component of the human diet in many regions of the world, provide vitamins A (β-carotene) and C, and are also a source of many other antioxidants such as capsaicin, dihydrocapsaicin, and phenols. Enhancing the concentration of antioxidants in plants grown in soil amended with recycled waste has not been completely investigated. Changes in pepper antioxidant content in relation to soil amendments and fruit development were investigated. The main objectives of this investigation were to: (i) quantify concentrations of capsaicin, dihydrocapsaicin, β-carotene, ascorbic acid, phenols, and soluble sugars in the fruits of Capsicum annuum L. (cv. Xcatic) grown under four soil management practices: yard waste (YW), sewage sludge (SS), chicken manure (CM), and no-much (NM) bare soil and (ii) monitor antioxidant concentrations in fruits of plants grown under these practices and during fruit ripening from green into red mature fruits. Total marketable pepper yield was increased by 34% and 15% in SS and CM treatments, respectively, compared to NM bare soil; whereas, the number of culls (fruits that fail to meet the requirements of foregoing grades) was lower in YW compared to SS and CM treatments. Regardless of fruit color, pepper fruits from YW amended soil contained the greatest concentrations of capsaicin and dihydrocapsaicin. When different colored pepper fruits (green, yellow, orange, and red) were analyzed, orange and red contained the greatest β-carotene and sugar contents; whereas, green fruits contained the greatest concentrations of total phenols and ascorbic acid.     

Assessment of the impact of pesticide residues on microbiological and biochemical parameters of tea garden soils in India

The main aim of this study was to assess the impact of pesticidal residues on soil microbial and biochemical parameters of the tea garden soils. The microbial biomass carbon (MBC), basal (BSR) and substrate induced respirations (SIR), β -glucosidase activity and fluorescein diacetate hydrolyzing activity (FDHA) of six tea garden soils, along with two adjacent forest soils (control) in West Bengal, India were measured. The biomass and its activities and biochemical parameters were generally lower in the tea garden soils than the control soils. The MBC of the soils ranged from 295.5 to 767.5 μ g g^{? 1}. The BSR and SIR ranged from 1.65 to 3.08 μ g CO₂-C g^{? 1} soil h^{? 1} and 3.08 to 10.76 μ g CO₂-C g^{? 1}h^{? 1} respectively. The β -glucosidase and FDHA of the soils varied from 33.3 and 76.3 μ g para-nitrophenol g^{? 1} soil h^{? 1} and 60.5 to 173.5 μ g fluorescein g^{? 1}h^{? 1}respectively. The tea garden soils contained variable residues of organophosphorus and organochlorine pesticides, which negatively affected the MBC, BSR, SIR, FDHA and β -glucosidase activity. Ethion and chlorpyriphos pesticide residues in all the tea garden soils varied from 5.00 to 527.8 ppb and 17.6 to 478.1 ppb respectively. The α endosulfan, β endosulfan and endosulfan sulfate pesticide residues in the tea garden soils ranged from 7.40 to 81.40 ppb, 8.50 to 256.1 ppb and 55 to 95.9 ppb respectively. Canonical correlation analysis shows that 93% of the total variation was associated with the negative impact of chlorpyriphos, β and α endosulfan and endosulfan sulfate on MBC, BSR and FDHA. At the same time ethion had negative impact on SIR and β -glucosidase. Data demonstrated that the pesticide residues had a strong impact on the microbial and biochemical components of soil quality.     

Hydroxypropyl-β-cyclodextrin as non-exhaustive extractant for organochlorine pesticides and polychlorinated biphenyls in muck soil

Hydroxypropyl-β-cyclodextrin (HPCD) was used as a non-exhaustive extractant for organochlorine pesticides (OCs) and polychlorinated biphenyls (PCBs) in muck soil. An optimized extraction method was developed which involved using a HPCD to soil mass ratio of 5.8 with a single extraction period of 20 h. An aging experiment was performed by spiking a muck soil with ¹³C-labeled OCs and non-labeled PCBs. The soil was extracted with the optimized HPCD method and Soxhlet apparatus with dichloromethane over 550 d periodically. The HPCD extractability of the spiked OCs was greater than of the native OCs. A decreased in HPCD extractability was observed for the spiked OCs after 550 d of aging and their extractability approached those of the natives. The partition coefficient between HPCD and soil (log K_CD-Soil) was negatively correlated with the octanol-water partition coefficient (log K_OW) with r² = 0.67 and p < 0.05.