环境浓度下邻苯二甲酸二乙酯对秀丽隐杆线虫的生态毒理效应

DEP (diethyl phthalate,邻苯二甲酸二乙酯)是一种在环境中普遍存在的具有潜在神经和生殖毒性的增塑剂,其会干扰环境生物的发育水平、运动行为及生化水平.以秀丽隐杆线虫的体长、体宽、头部摆动频率及生化指标作为测试终点,评估环境中DEP对秀丽隐杆线虫的生态毒理效应.在不同环境浓度(0、0.000 2、0.002、0.02、0.2、2 mg/L)的DEP溶液中,对秀丽隐杆线虫进行不同时间(24 h、72 h和10 d)的暴露试验.结果表明:①在不同浓度DEP溶液中暴露24 h后,秀丽隐杆线虫的发育水平均未受到显著影响(P>0.05).②在不同浓度DEP溶液中暴露72 h后,秀丽隐杆线虫的发育水平受到干扰.与对照组相比,在DEP浓度最高(2 mg/L)时,秀丽隐杆线虫体长下降了3.21%(P < 0.05);在DEP浓度为0.000 2 mg/L时,秀丽隐杆线虫的体宽呈上升趋势,且头部摆动频率明显加快了5.52%(P < 0.01),秀丽隐杆线虫的发育水平受到显著抑制.③在不同浓度DEP溶液中暴露10 d后,与对照组相比,秀丽隐杆线虫的体长、体宽和头摆频率均出现下降;在DEP浓度为2 mg/L时,秀丽隐杆线虫体内活性氧自由基、脂褐素和细胞凋亡水平累积均增长显著,出现氧化应激损伤.研究显示,不同环境浓度的DEP溶液会对秀丽隐杆线虫产生一定的毒性影响,且不同暴露时间和暴露浓度产生的毒性影响也存在一定差异.      

Effect of free-air CO2 enrichment on nematode communities in a Chinese farmland ecosystem

At a rice-wheat rotational free-air CO2 enrichment(FACE) platform, the effect of elevated atmospheric CO2 on soil nematode communities in a farmland ecosystem was studied. Wheat plots were exposed to elevated atmospheric CO2 (ambient 370 μl/L 200 μl/L).32 families and 40 genera of nematode were observed in soil suspensions during the study period. Under FACE treatment, the numbers of total nematodes, bacterivores and fungivores exhibited an increasing trend. Because of the seasonal variation of soil temperature and moisture, the effect of elevated atmospheric CO2 on soil nematodes was only observed under favorable conditions. The response of nematode communities to elevated atmospheric CO2 may indicate the change of soil food web.     

土壤中三价锑的老化对秀丽隐杆线虫毒性的影响

为明确老化过程对土壤外源三价锑〔Sb(Ⅲ)〕毒性的影响,结合土壤中Sb的化学分析和生物毒性测试,以模式生物秀丽隐杆线虫(Caenorhabditis elegans)为测试生物,研究经Sb(Ⅲ)处理后老化7和56 d的2种土壤(安徽黄棕壤和新疆灰漠土)中不同价态Sb浓度、可提取态Sb浓度以及对线虫生长、生育、繁殖毒性的变化. 结果表明:①经Sb(Ⅲ)处理后老化56 d的安徽黄棕壤和新疆灰漠土中Sb(Ⅴ)的占比均显著高于老化7 d的土壤,与安徽黄棕壤相比,新疆灰漠土中Sb(Ⅲ)能更快地转化为毒性较低的Sb(Ⅴ). ②相较经Sb(Ⅲ)处理后老化7 d的土壤,经56 d老化的安徽黄棕壤和新疆灰漠土中可提取态Sb浓度分别下降了9.3%~36.8%和3.3%~47.0%. ③经Sb(Ⅲ)处理后老化56 d的安徽黄棕壤和新疆灰漠土对线虫生长毒性的EC₅₀(50%效应浓度)值较老化7 d的土壤分别提升1.7和2.3倍,对线虫生育毒性的EC₅₀值分别提升1.1和2.4倍,对线虫繁殖毒性的EC₅₀值分别提升1.2和1.9倍. 研究显示,老化过程可降低土壤中可提取态Sb浓度和毒性较高的Sb(Ⅲ)占比,导致外源Sb(Ⅲ)对线虫毒性的减弱,pH、有机质含量以及铁锰铝氧化物含量对土壤中Sb(Ⅲ)氧化和Sb吸附过程的影响导致外源Sb(Ⅲ)老化效应以及对线虫毒性的差异.      

生物炭中持久性自由基对秀丽隐杆线虫的毒性

为了评价生物炭的使用对生态系统,尤其是对土壤无脊椎动物的毒性影响,使用模式生物秀丽隐杆线虫（Caenorhabditis elegans,C.elegans）来评估生物炭的环境风险.观察了生物炭原样、生物炭颗粒物和生物炭浸提液对线虫神经行为学评价指标（身体摆动频率、相对运动长度、排泄间隔时间、碰触反应率和化学感知行为指数）的影响;并结合生物炭的理化性质、非金属元素组成和重金属元素含量以及环境持久性自由基（EPFRs）的强度,评估生物炭对线虫的生物毒性.结果显示,EPFRs信号强的生物炭和颗粒物对秀丽隐杆线虫有一定的毒物兴奋效应,EPFRs信号微弱的浸提液无显著性影响.因此,生物炭中的EPFRs对秀丽隐杆线虫有潜在的神经毒性作用.     

接种孢囊线虫对大豆生长的影响

在温室条件下,研究了不同品种大豆接种大豆孢囊线虫对其根系生长、根瘤及几种矿质元素吸收总量、转移量的影响。结果表明,接种线虫后易感病品种绥农１４根瘤数减少,根瘤活性降低,与不接种处理差异显著;感病品种合丰２５总根长减少２,与不接种处理差异显著。易感病品种绥农１４接种线虫后Ｐ元素的吸收总量降低,与不接种处理差异显著。易感病品种绥农１４接种线虫后Ｐ元素的吸收总量降低,与不接种处理差异显著。感病品种合丰２     

Using the nematode Caenorhabditis elegans as a model animal for assessing the toxicity induced by microcystin-LR

Among more than 75 variants of microcystin(MC),microcystin-LR(MC-LR) is one of the most common toxins.In this study,the feasibility of using Caenorhabditis elegans to evaluate MC-LR toxicity was studied.C.elegans was treated with MC-LR at different concentrations ranging from 0.1 to 80 μg/L.The results showed that MC-LR could reduce lifespan,delay development,lengthen generation time,decrease brood size,suppress locomotion behavior,and decreases hsp-16-2-gfp expression.The endpoints of generation time,brood...     

Induction of chemotaxis to sodium chloride and diacetyl and thermotaxis defects by microcystin-LR exposure in nematode Caenorhabditis elegans

Apart from the liver disruption, embryotoxicity and genotoxicity, microcystin (MC)-LR also could cause neurotoxicity. Nematode Caenorhabditis elegans was explored as a model to study the neurotoxicity. In the present study, we provided evidence to indicate the neurotoxicity on chemotaxis to NaCl and diacetyl, and thermotaxis from MC-LR exposure to C. elegans. As a result, higher concentrations of MC-LR caused significantly severe defects of chemotaxis to NaC1 and diacetyl, and thermotaxis. The neurotoxicity on chemotaxis to NaCl and diacetyl, and thennotaxis from MC-LR exposure might be largely mediated by the damage on the corresponding sensory neurons (ASE, AWA, and AFD) and interneuron AIY. The expression levels of che-1 and odr-7 were significantly decreased (P<0.01) in animals exposed to MC-LR at concentrations lower than 10 μg/L, whereas the expression levels of ttx-1 and ttx-3 could be significantly (P<0.01) lowered in animals even exposed to 1 μg/L of MC-LR. Moreover, both the chemotaxis to NaCl and diacetyl and the thermotaxis were more significantly reduced m MC-LR exposed mutants of che-1(p674), odr-7(ky4), ttx-1(p767), and ttx-3(ks5) than those in exposed wild-type N2 animals at the same concentrations.     

Adverse effects of metal exposure on chemotaxis towards water-soluble attractants regulated mainly by ASE sensory neuron in nematode Caenorhabditis elegans

Chemotaxis to water-soluble attractants is mainly controlled by ASE sensory neuron whose specification is regulated by che-1 in Caenorhabditis elegans. Our data suggested that exposure to high concentrations of metals, such as Pb, Cu, Ag, and Cr, would result in severe defects of chemotaxis to water-soluble attractants of NaCl, cAMP, and biotin. Moreover, the morphology of ASE neuron structures as observed by relative fluorescent intensities and relative size of fluorescent puncta of cell bodies, relative lengths of sensory endings in ASE neurons, and the expression patterns of che-1 were obviously altered in metal exposed animals when they meanwhile exhibited obvious chemotaxis defects to water-soluble attractants. In addition, the dendrite morphology could be noticeably changed in animals exposed to 150 mol/L of Pb, Cu, and Ag. Furthermore, we observed significant decreases of chemotaxis to water-soluble attractants in Pb exposed che-1 mutant at concentrations more than 2.5 mol/L, and in Cu, Ag, and Cr exposed che-1 mutant at concentrations more than 50 mol/L. Therefore, impairment of the ASE neuron structures and functions may largely contribute to the appearance of chemotaxis defects to water-soluble attractants in metal exposed nematodes.     

重金属对秀丽隐杆线虫繁殖的影响

为了探究重金属单独及联合暴露对秀丽隐杆线虫(Caenorhabditis elegans)繁殖的影响及其作用机制,采用96孔板液相暴露试验,以环境相关浓度(0.1~50.0 μg/L)的Cd、Hg、Pb暴露同步化处理秀丽隐杆线虫,24 h后统计其怀卵数及阴门畸形率,以及连续记录72 h内子一代秀丽隐杆线虫的个体数,最后利用2×2析因设计方差分析阐明重金属的两两联合作用模式. 结果表明:与对照组相比,Cd、Hg、Pb单独及联合暴露对秀丽隐杆线虫的繁殖具有显著抑制作用,ρ(Cd)为50.0 μg/L、ρ(Hg)为10.0 μg/L、ρ(Pb)为50.0 μg/L暴露组秀丽隐杆线虫子一代数量分别降低了43.5%、33.8%、51.0%;Cd-Hg暴露组〔当ρ(Cd)、ρ(Hg)分别为50.0、10.0 μg/L时〕、Hg-Pb暴露组〔当ρ(Hg)、ρ(Pb)分别为10.0、50.0 μg/L时〕、Cd-Pb暴露组〔当ρ(Cd)、ρ(Pb)分别为50.0、50.0 μg/L时〕秀丽隐杆线虫子一代个体数分别降低了44.7%、61.0%、53.3%. 进一步研究发现,Cd、Hg、Pb单独及联合暴露会引起秀丽隐杆线虫子宫内受精卵数量降低以及产卵器阴门结构畸形率升高. 2×2析因设计方差分析结果发现,Cd、Hg、Pb两两联合暴露对秀丽隐杆线虫的繁殖表现为没有交互作用或者交互方式为拮抗. 研究显示,秀丽隐杆线虫子宫内怀卵数的降低是其子一代数量显著减少的主要原因,而阴门结构的损伤可能使产卵行为受损,从而进一步加剧重金属对秀丽隐杆线虫繁殖的抑制作用.      

保护性耕作土壤线虫成熟度及区系分析

土壤线虫的生活史和功能多样性能够反映土壤健康质量和生态环境的演变,耕作措施的改变可能通过影响土壤环境进而影响土壤线虫的生活史和功能多样性,然而关于保护性耕作条件下土壤线虫成熟度及区系分析的研究,国内外尚鲜见报道。为了深入揭示土壤线虫对保护性耕作土壤生态环境变化的生物指示作用,以辽宁彰武县保护性耕作示范推广基地土壤为研究对象,通过实地调查和取样分析,对比研究了传统犁耕和6年保护性耕作（免耕秸秆覆盖）条件下的土壤线虫成熟度指数及区系分析。研究发现,与犁耕相比,保护性耕作显著降低了表层土壤自由生活线虫成熟指数MI、总成熟指数MMI、c-p值为2~5的自由生活线虫成熟指数MI2–5和总成熟指数MMI2–5,降低幅度分别为11%、9%、9%和10%,然而对植物寄生线虫成熟指数PPI以及PPI/MI比值的影响不明显。线虫区系分析结果表明,保护性耕作土壤线虫的富集指数EI和结构指数SI,比犁耕土壤分别显著降低56%和24%。保护性耕作造成的土壤pH降低和可能带来的土壤农药污染,可能是导致其上述影响的主要原因。简单相关分析和主成分分析结果证明,线虫成熟指数MI、MMI、MI2–5和MMI2–5以及结构指数SI与土壤pH关系密切。综上,土壤线虫生活史多样性和功能多样性对于揭示保护性耕作对土壤环境的影响具有良好的作用。