Characterization of the microsomal epoxide hydrolase of hepatic microsomes of the common dab,Limanda limanda

Epoxide hydrolase of microsomal membranes of the common dab (Limanda limanda) has been characterized using p-nitrostyrene oxide as substrate. Under the conditions of assay used, the turnover number with this substrate was higher than found for the more frequently used styrene oxide and steady state kinetics were observed. The enzyme had a K_M of 0.12 mM and optima for pH and temperature between pH 8–10.2 and 50–60°C respectively. Enzyme activity was unaffected by low concentrations of ionic and non-ionic detergents but was inhibited by higher concentrations of Lubrol and Brij. The enzyme protein did not react with monospecific antibodies to rat or human microsomal epoxide hydrolase during Western blotting. Large inter-individual variation in enzyme activity was found but the enzyme does not appear to be expressed in a gender-specific way. Fish were administered a wide range of hydrocarbons which are known to alter the expression of cytochrome P450 1A but these had no effect other than benzothiophene which caused a small increase in enzyme activity.Abbreviations mEH microsomal epoxide hydrolase - pNSG p-nitrostyrene glycol - pNSO p-nitrostyrene oxide     

毛细管气相色谱法测定海洋贝类体内的石油烃

介绍了一种分离测定海洋贝类体内石油烃组分的方法。样品经皂化、萃取、脱水、浓缩等步骤的处理后，用氧化铝层析柱将石油烃分为芳烃类和烷烃类两部分，并将之分别浓缩，用配备FID检测器的毛细管气相色谱测定。在本测定方法设置的色谱条件下，各种芳烃和正构烷烃组分能够被较好的分离；芳烃和正构烷烃的最低检出限范围分别为4．21×10－9～18．10×10－9g和0．84×10－8～19．66×10-8g，峰面积的变异系数范围分别为4．61％～16．48％和0．41％～0．78％，绝对保留时间的变异系数范围分别为6．41％～31．0％和0．54％～1．18％，方法回收年范围分别为37．9％～101．8％和35．1％～55．7％。但如果用经与样品相同前处理过程的混合标准进行回收率计算，可将芳烃和正构烷烃的回收率提高到84．2％～119．6％。     

Synergetic effects of cell immobilization in polyurethane foam and use of thermotolerant strain on degradation of mixed hydrocarbon substrate by Prototheca zopfii

ABSTRACT:   The synergetic effects of an immobilized cell system in an oleophilic polyurethane foam (PUF) and use of a thermotolerant strain on degradation of hydrocarbons by colorless green microalga Prototheca zopfii are reported. Two strains of P. zopfii , i.e. thermotolerant RND16 and non-thermotolerant ATCC30253, were immobilized in PUF to compare their abilities to biodegrade a mixed hydrocarbon substrate (MHS) containing aliphatic and polycyclic aromatic hydrocarbons (PAHs), as a function of temperature. The thermotolerant strain RND16 degraded MHS at 35°C, while ATCC30253 did not degrade hydrocarbons at temperatures higher than 30°C. Immobilization of P. zopfii in PUF resulted in shortened lag for growth-associated biodegradation of n -alkanes in MHS, the effect of which was most significant in cultures of RND16 at 25°C. Nevertheless, the decrease in the amount of degraded PAHs was caused by PUF immobilization and the level of this decrease was marked in the cultures of RND16, in which rate and extent of n -alkane degradation were higher than for ATCC30253.     

西花蓟马分类鉴定方法的研究进展

西花蓟马Frankliniella occidentalis(Pergande)是一种危险性外来入侵害虫,虫体小,鉴定困难。本文总结了国内外西花蓟马分类鉴定方法的研究进展,包括形态学鉴别、分子生物学方法以及基于表皮碳氢化合物分析的生化分类方法,并讨论了各种分类方法的优势和弊端,最后对西花蓟马的分类研究前景进行了展望。     

长江三角洲地区土壤环境质量与修复研究 Ⅳ.多环芳烃在土壤不同有机质组分中分配特征的研究

多环芳烃(PAHs)在土壤不同活性有机质库中的分配会影响它们在土壤中的迁移和生物有效性。本研究采用土壤有机无机复合体的分组方法,分离出以游离态有机物质存在的轻组和以有机无机复合体存在的重组,研究了15种美国环境保护署(USEPA)优控的PAHs在土壤轻组和重组以及重组结合态腐殖质不同组分中的分配特征。结果表明,轻组中PAHs总量的含量范围为1.30×104~1.07×105μg kg-1,远远高于PAHs总量的含量为221.7~297.8μg kg-1的重组。土壤中轻组的含量虽然只有0.4%~2.3%,但它结合的PAHs量却占土壤中PAHs总量的31.5%~69.5%。重组中PAHs含量主要分布在紧结态腐殖质中,占重组PAHs总量71.2%~87.2%。结合态腐殖质不同组分中PAHs的含量与它们有机碳的含量呈显著性正相关(p<0.01),紧结态腐殖质对PAHs的富集能力显著高于稳结态和松结态腐殖质。PAHs污染土壤的环境风险可能主要在于轻组结合的PAHs。     

影响土壤中PAHs降解的环境因素及促进降解的措施

土壤中的多环芳烃(PAHs)类有机污染物的生物有效性低,不易降解。本文综述了影响污染土壤中多环芳烃降解的环境因素和促进降解措施的研究进展。影响土壤中多环芳烃降解的因素,包括水分、养分、土壤物理条件等;促进土壤中多环芳烃降解的措施有:向污染土壤添加有机溶剂、利用冯顿反应、添加堆肥和有机物料等。从目前研究来看,应当通过促进多环芳烃从土壤上解吸和培育具有较高多环芳烃降解能力的微生物来促进多环芳烃污染土壤的修复。     

几种豆科、禾本科植物对多环芳烃复合污染土壤的修复

通过盆栽试验,研究了几种豆科植物与禾本科植物对多环芳烃(PAHs)复合污染土壤的修复作用。结果显示,90天后8种植物对土壤中PAHs均有不同程度降解效果,其中紫花苜蓿和多年生黑麦草对土壤PAHs的去除率分别达48.4%、46.8%,且对3环PAHs去除较为彻底,对4环及4环以上的PAHs去除效果较差。8种供试植物对PAHs均有一定的吸收、富集与转运的能力,紫花苜蓿和多年生黑麦草对土壤PAHs的生物富集系数分别为0.096、0.085,其提取修复效率为0.017%和0.013%。可见,紫花苜蓿和多年生黑麦草具有较好的根际修复潜力。     

Termite cuticular extracts improve acceptance of bait for controlling invasive Asian needle ants,Brachyponera chinensis

BACKGROUND

The Asian needle ant, Brachyponera chinensis, is an invasive ant currently spreading in urban and natural habitats throughout the eastern United States. Recent studies have documented the negative impact of B. chinensis on native ecosystems and human health, yet effective control strategies are lacking. Control difficulties are, in part, due to the unique biology of B. chinensis, which is a predatory ant and a termite specialist. Given that subterranean termites are an important nutritional resource for B. chinensis, the current study evaluated the potential of termite cuticular extract to improve the target-specificity and efficacy of commercial bait used for B. chinensis control.

RESULTS

The efficacy of bait augmented with termite cuticular extracts was evaluated in laboratory and field trials. In laboratory assays, B. chinensis colonies were offered granular bait treated with termite cuticular extract. Results demonstrated that the acceptance of commercial bait is significantly increased by the addition of termite cuticular extract or synthetic (Z)-9-pentacosene, a major component of termite cuticular extract. Foraging activity of Asian needle ants was significantly greater on baits augmented with termite cuticular extract or (Z)-9-pentacosene relative to standard bait. Furthermore, bait augmented with termite cuticular extract worked substantially faster relative to standard bait. To evaluate population effects, field studies were conducted in forested areas invaded by B. chinensis. Bait treated with termite cuticular extract scattered on the forest floor provided rapid control of B. chinensis and ant densities throughout the treated plots declined by 98% within 14 days.

CONCLUSION

The incorporation of termite cuticular extracts and individual cuticular hydrocarbons such as (Z)-9-pentacosene into traditional baits used for B. chinensis control may offer a novel tool to manage this increasingly problematic invasive ant. © 2023 The Author. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.     

Remediation of polycyclic aromatic hydrocarbon-contaminated soils using microbes and nanoparticles: A review

Polycyclic aromatic hydrocarbon(PAH) pollution is a global concern because of their toxicity to environment and ecosystem, which induces adverse effects on plants, animals, and humans. Hydrocarbons are mainly released from natural and anthropogenic activities, such as incomplete fuel combustion, leakages in oil pipelines, and the extensive use of pesticides; PAH contaminants include petroleum hydrocarbons(PHCs), halogenated hydrocarbons, chlorophenols, and pesticides. Bioremediation using microo...     

Assessment of organic compost and biochar in promoting phytoremediation of crude-oil contaminated soil using Calendula officinalis in the Loess Plateau,China

The Loess Plateau, located in Gansu Province, is an important energy base in China because most of the oil and gas resources are distributed in Gansu Province. In the last 40 a, ecological environment in this region has been extremely destroyed due to the over-exploitation of crude-oil resources. Remediation of crude-oil contaminated soil in this area remains to be a challenging task. In this study, in order to elucidate the effects of organic compost and biochar on phytoremediation of crude-oil contaminated soil(20 g/kg) by Calendula officinalis, we designed five treatments, i.e., natural attenuation(CK), planted C. officinalis only(P), planted C. officinalis with biochar amendment(PB), planted C. officinalis with organic compost amendment(PC), and planted C. officinalis with co-amendment of biochar and organic compost(PBC). After 152 d of cultivation, total petroleum hydrocarbons(TPH) removal rates of CK, P, PB, PC and PBC were 6.36%, 50.08%, 39.58%, 73.10% and 59.87%, respectively. Shoot and root dry weights of C. officinalis significantly increased by 172.31% and 80.96% under PC and 311.61% and 145.43% under PBC, respectively as compared with P(P0.05). Total chlorophyll contents in leaves of C. officinalis under P, PC and PBC significantly increased by 77.36%, 125.50% and 79.80%, respectively(P0.05) as compared with PB. Physical-chemical characteristics and enzymatic activity of soil in different treatments were also assessed. The highest total N, total P, available N, available P and SOM(soil organic matter) occurred in PC, followed by PBC(P0.05). C. officinalis rhizospheric soil dehydrogenase(DHA) and polyphenol oxidase(PPO) activities in PB were lower than those of other treatments(P0.05). The values of ACE(abundance-based coverage estimators) and Chao 1 indices for rhizospheric bacteria were the highest under PC followed by PBC, P, PB and CK(P0.05). However, the Shannon index for bacteria was the highest under PC and PBC, followed by P, PB and CK(P0.05). In terms of soil microbial community composition, Proteiniphilum, Immundisolibacteraceae and Solimonadaceae were relatively more abundant under PC and PBC. Relative abundances of Pseudallescheria, Ochroconis, Fusarium, Sarocladium, Podospora, Apodus, Pyrenochaetopsis and Schizothecium under PC and PBC were higher, while relative abundances of Gliomastix, Aspergillus and Alternaria were lower under PC and PBC. As per the nonmetric multidimensional scaling(NMDS) analysis, application of organic compost significantly promoted soil N and P contents, shoot length, root vitality, chlorophyll ratio, total chlorophyll, abundance and diversity of rhizospheric soil microbial community in C. officinalis. A high p H value and lower soil N and P contents induced by biochar, altered C. officinalis rhizospheric soil microbial community composition, which might have restrained its phytoremediation efficiency. The results suggest that organic compost-assisted C. officinalis phytoremediation for crude-oil contaminated soil was highly effective in the Loess Plateau, China.