Biomarker response in the earthworm Lumbricus terrestris exposed to chemical pollutants

Earthworms are important organisms for the soil ecosystem. They are sensitive to toxic chemicals and represent useful bioindicator organisms for soil biomonitoring. Recently the use of biomarkers in earthworms has been increasingly investigated for soil monitoring and assessment purpose. The aim of the preset paper was to analyze the pollutant-induced response of a suite of cellular and biochemical biomarkers in the earthworm Lumbricus terrestris exposed to copper sulphate or methiocarb in OECD soil at the maximal concentrations recommended in agriculture. These responses were compared to lifecycle parameters such as survival, growth and reproduction.Granulocyte morphometric alteration, lysosomal membrane stability, metallothionein concentration, and acetylcholinesterase activity were considered. In either copper sulphate or methiocarb exposure conditions the mean percentage variation of the pollutant-induced molecular and cellular biomarkers was consistent with the whole organism end-point responses. In particular pollutant-induced granulocyte enlargement, detected in either copper sulphate or methiocarb exposed organisms, showed to be a potential general biomarker that may be directly linked to organism health. Compared to the other biological responses to pollutants, it showed high sensitivity to pollutant exposure suggesting its possible applications as a sensitive, simple, and quick general biomarker for monitoring and assessment applications.     

蚯蚓脱氧核糖核酸酶的底物特异性及降解产物的特性

目的研究蚯蚓组织中一种新型脱氧核糖核酸酶(EWD)的底物特异性及降解产物的特性。方法采用ZOR-BAX-Oligo柱-HPLC、琼脂糖凝胶电泳、紫外分光光度法等技术,分析EWD对环状质粒DNA、线状λ-DNA、大肠杆菌基因组的降解作用,及对真核鲱精DNA、单链DNA等的降解中间产物和终产物的特性,并观察其对RNA的降解作用。结果EWD对这几种DNA均有降解作用,降解产物为较均一的、小于18bp的寡核苷酸。但EWD对RNA无降解作用。结论EWD为脱氧核糖核酸内切酶类。     

蚯蚓对As污染土壤酶活性及其P养分的影响

从湖南石门县的As矿区附近采集不同程度As污染的农田土壤,分别设置添加秸秆、接种蚯蚓等处理,研究蚯蚓对As污染土壤酶活性及其P养分供给的影响。结果发现,高浓度As土壤的脱氢酶活性显著低于中、低浓度As土壤,而酸性磷酸酶活性及有效P含量则与之相反。蚯蚓 20g秸秆处理在50d时脱氢酶活性最高,而酸性磷酸酶活性则是秸秆处理在100d时最高,且接种蚯蚓和施用秸秆有利于土壤P素的释放。结果表明在施用秸秆条件下接种蚯蚓有利于改善As污染土壤的养分供给,从而改善根际营养。     

土壤中重金属污染对白颈环毛蚓（Pheretime Califonica）胃肠道粘膜损伤的扫描电镜观察

本文首次报道了土壤重金属污染区的白颈环毛蚓（ｐｈｅｒｅｔｉｍｅＣａｌｉｆｏｎｉｃａ）胃肠道粘膜的扫描电镜观察，结果表明：在重污染区（Ⅰ区）蚯蚓胃粘膜出现溃疡灶，并发现有穿孔现象；在轻污染区（Ⅳ区）只发现有胃微绒毛萎缩现象。又在重污染区（Ⅰ区）发现蚯蚓肠粘膜微绒毛有明显的萎缩现象。我们首次发现蚯蚓肠粘膜上存有纤毛丛。对照区肠粘膜上纤毛整齐健壮，而在重污染区（Ⅰ区）发现肠粘膜上纤毛发生紊乱以及萎缩、纤毛顶端发生融结膨大现象。肠粘膜纤毛的病变能很灵敏地反映土壤中重金属危害排泄功能的状况。由此，我们认为：肠道纤毛的病变状况可作为土壤重金属污染监测的一项生物学指标。     

Accounting for particle movement when assessing the dissolution of slow release fertilizers in field soils

When fine particulate, slow-release fertilizers are applied to pastures, earthworm activity can physically move the particles both horizontally and vertically in the soil. This physical movement needs to be accounted for when researchers attempt to determine the rate of fertilizer dissolution by measuring the quantity of undissolved fertilizer residue remaining in the soil. A hard igneous phosphate rock (Phalaborwa PR) and an inert chromite ore were used as tracers to follow the physical movement of the reactive PR (RPR), NCPR applied to grazed pasture on a Pallic Soil (Aeric Fragiaqualf) isolated in galvanised steel cylindrical cores (150 mm diameter and 100 mm height) with or without nylon mesh sleeve (63 µm) at the bottom. The soil cores were sampled after 113, 270 and 559 days and analysed for PR and chromite residues. Results from both tracers showed that there was a significant movement of particles laterally out of the cores and vertically below 40 mm soil depth. Phalaborwa PR particle movement to 40–60 mm soil depth was 8% in 112 days and 24% in 270 days. Between 270 and 559 days no significant movement of particles was observed. Particle movement appeared to occur in discrete non-continuous events that were associated with the major end-of-autumn peaks in earthworm activity. When corrected for particle movement, the measured rate of NCPR dissolution satisfactorily fitted the rate of dissolution predicted by two models of PR dissolution.     

用INAA法和ICP-MS法对蚯蚓样品作多元素测定比较

用仪器中子活化分析方法对６例蚯蚓样品进行了Ａｓ、Ｂａ、Ｃｄ、Ｃｏ、Ｃｒ、Ｃｕ、Ｆｅ、Ｍｎ、Ｈｇ、Ｒｂ、Ｓｂ、Ｓｅ和Ｚｎ的元素含量测定,并用等离子质谱分析方法和人发标准参考物质进行了比较和核对。结果表明,两种测定方法分析结果相符,大多数元素的相对偏差在±２０％以内。     

Residual crude oil concentrations and ecotoxicity of polluted tropical soils after phytoremediation

Changes in residual crude oil concentrations and soil ecotoxicity during the phytoremediation assessment of tropical plants growing on crude oil-polluted soils were evaluated in a greenhouse study. The plants (Panicum maximum, Zea mays, Centrosema spp. and Pueraria spp.) were grown in weathered polluted soil samples in microcosms for 10?weeks. Residual crude oil in soil was quantified colorimetrically, while the ecotoxicity of the vegetated and control soil samples were evaluated using earthworms’ percentage survival and crop seeds’ germination bioassays. It was observed that planting of 1% (w/w) polluted soil samples reduced crude oil in the rhizosphere soils of P. maximum and Centrosema spp. by 71.6?±?1.4 and 55.3?±?4.3%, respectively. These are in contrast with 37.5?±?2.5% reduction in non-vegetated control soil samples. The ecotoxicity assays indicated that planting also effected reduction of crude oils’ toxicity positively. There were 100, 40?±?28.3 and 50?±?21.1% survival of test earthworms, respectively, after 24?h in 1% w/w polluted soil samples phytoremediated with P. maximum, Centrosema spp. and Pueraria spp. as against 0% survival in non-vegetated control samples. The observed sensitivity of the test organisms to chemical stress bodes well for providing rapid information on effectiveness of remediation programmes.     

以蚯蚓为原料制备生物态含铁蛋白质纯品

以获取高营养性的蚯蚓含铁蛋白质为目的，根据蚯蚓体内血红蛋白分子结构的特性与分布状态，采用了双水相萃取等分离纯化工艺进行了制备生物态含铁蛋白质纯品的研究。结果表明，用聚乙二醇（12％，W／W）．硫酸铵（12％，W／W）组成的双水相萃取样品后直接用等电点沉淀法，即在pH约为5．1的缓冲液中进行透析可获得高纯度的蚯蚓含铁蛋白。在此基础上若再采用Q Scpharosc fast flow离子交换层析和梯度洗脱的方法就能使产品的质量进一步提高。综合分析说明了研究中所采用的工艺较简单，成本不高，可操作性好，且能获得高品质的含铁蛋白质产品。研究为从食品层面上利用开发蚯蚓、推动饲养蚯蚓产业的发展和制备补血功能食品等提供了实验数据。     

Enantiomer-specific toxicity and bioaccumulation of alpha-cypermethrin to earthworm Eisenia fetida

Alpha-cypermethrin, a synthetic pyrethroid, is highly effective against a wide range of chewing and sucking insects in crops, and it is a racemic mixture of two enantiomers ((+)-1R-cis-αS + (−)-1S-cis-αR). Studies about the toxicity of alpha-cypermethrin to non-target organisms are mainly focused on aquatic organisms, whereas information regarding terrestrial organisms is relatively much less. Very little report about its enantioselective toxicity is known, so the present study tested the enantiomer-specific acute toxicity to earthworm Eisenia fetida. Experiment about bioaccumulation of two enantiomers in soil was conducted, peak-shaped accumulation curves were observed for both enantiomers, and the calculated biota to soil accumulations factor (BSAF) have significant difference between the two enantiomers. It was obvious that earthworm can uptake alpha-cypermethrin enantioselectively, preferentially accumulating (−)-(1S-cis-αR)-enantiomer. Great difference in toxicity to earthworm between two enantiomers was found, and the calculated LC₅₀ values for (+)-(1R-cis-αS)-, (−)-(1S-cis-αR)-, and rac-alpha-cypermethrin were 49.53, 1663.87 and 165.61 ng/cm², respectively. The acute toxicity of alpha-cypermethrin enantiomers was enantioselective.