白眉蝮蛇毒精氨酸酯酶对CHL细胞增殖抑制和染色体畸变的影响

研究了蝮蛇清栓酶的有效成分精氨酸酯酶体外对中国仓鼠肺成纤维细胞 (CHL)增殖和染色体畸变的影响 .精氨酸酯酶的浓度以酶活单位U表示 .细胞增殖抑制试验和染色体畸变试验都用两种方法 :直接法和代谢活性法 .精氨酸酯酶设 3个浓度 :1.0× 10 -3 U /mL ,0 .5× 10 -3 U /mL和 0 .2 5× 10 -3U/mL .其中最高浓度比临床治疗浓度高约10 0倍 .细胞增殖抑制试验采用细胞贴壁培养 ,乙醇固定 ,结晶紫染色 ,单层细胞密度计测定细胞密度 .染色体畸变试验采用给药后 2 4h和 48h收集中期分裂细胞 ,低渗固定 ,制片 ,Giemsa染色 ,观察 10 0个中期分裂细胞的染色体结构异常及多倍体的出现率 .试验结果表明 ,精氨酸酯酶在上述浓度对CHL细胞的增殖没有抑制作用 ,对CHL细胞的染色体结构也没有影响 .表 2参 10     

How do slugs cope with toxic alkaloids?

Summary. Arion lusitanicus and other slugs are able to feed on a variety of plants, even those containing toxic secondary metabolites, such as alkaloids. Alkaloids, like sparteine, lupanine, quinidine and atropine are avoided in no-choice feeding experiments only when they are present in concentrations above 1 mg/g food pellet. Alkaloids (sparteine, lupanine, cytisine, quinidine, atropine, senecionine, eserine, and harmaline) are toxic to Arion lusitanicus when injected. LD₅₀ values are 10 to 20 fold higher than in vertebrates indicating that slugs have a high tolerance towards food toxins. The tolerance is higher in young animals than in adult slugs. Injected alkaloids are rapidly detoxified within 72 h. Tolerance and detoxification can be induced by feeding slugs on non-lethal doses of lupin alkaloids. Using isolated microsomal preparations from the digestive gland, active detoxification was observed in vitro. Evidence is presented that cytochrome p450 plays an important role in detoxification of the applied alkaloids. A powerful and inducible detoxification systems appears to be the main mechanism that allows slugs to feed on plants rich in secondary metabolites (when no other food is available), that are usually avoided by other herbivores.     

Recovery of Faunal Communities During Tropical Forest Regeneration

Abstract:  As mature tropical forests are cleared, secondary forests may play an important role in the conservation of animal species, depending on how fast animal communities recover during forest regeneration. I reviewed published studies on the recovery of animal species richness and composition during tropical forest regeneration. In 38 of the 39 data sets I examined, conversion of forest to agriculture or pasture substantially reduced species richness. Given suitable conditions for forest recovery, the species richness of the animal taxa considered can be predicted to resemble that of mature forests roughly 20–40 years after land abandonment. At least for ants and birds, however, recovery of species composition appears to take substantially longer than recovery of species richness. Because species richness for many taxa appears to recover relatively rapidly in secondary forests, conservation of secondary forests may be an effective investment in future diversity. The slower recovery of species composition indicates, however, that some species will require stands of mature forest to persist.     

Pyrrolizidine alkaloids on three trophic levels – evidence for toxic and deterrent effects on phytophages and predators

Summary. Pyrrolizidine alkaloids (PAs) present a model system in the investigation of tritrophic interactions mediated by plant secondary compounds. However, their toxicity for insect herbivores has never been experimentally proven. Here, we demonstrate the toxic effects of a PA on growth and survival of the eri silk moth Philosamia ricini. In a feeding experiment, larvae of this generalist herbivore fed with an artificial PA diet gained weight significantly slower than control animals, and died as pupae. We suggest that derivatives of the ingested PA N-oxide damage developmental functions during metamorphosis. A tracer test with [¹⁴C]senecionine N-oxide revealed that the caterpillars lack adaptations that would prevent conversion of the chemical into the pro-toxic free base. In contrast, the PA adapted leaf beetle Longitarsus anchusae accumulates PAs as N-oxides. We tested the purpose of sequestration in this species as defence against predators. Through a series of prey choice experiments with three carabid predator species, chemically non-protected bark beetle pupae were chosen almost uniformly over L. anchusae pupae. In a following choice test with one of these predators, artificially PA-treated mealworm segments deterred the predator from feeding. Overall the study corroborates the immediate toxic effect of PAs on non-adapted herbivores and the protective effect that adapted insects may gain by sequestering them. It thereby underlines the potential for PAs to play a central role in multitrophic interactions between plants, phytophages and their predators.     

Simulated and experimental evaluation of factors affecting the rate and extent of reductive dehalogenation of chloroethenes with glucose

Carbohydrates such as molasses are being added to aquifers to serve as electron donors for reductive dehalogenation of chloroethenes. Glucose, as a model carbohydrate, was studied to better understand the processes involved and to evaluate the effectiveness for dehalogenation of different approaches for carbohydrate addition. A simulation model was developed and calibrated with experimental data for the reductive dehalogenation of tetrachloroethene to ethene via cis-1,2-dichloroethene. The model included fermentors that convert the primary donor (glucose) into butyrate, acetate and hydrogen, methanogens, and two separate dehalogenator groups. The dehalogenation groups use the hydrogen intermediate as an electron donor and the different haloethenes as electron acceptors through competitive inhibition. Model simulations suggest first that the initial relative population size of dehalogenators and H(2)-utilizing methanogens greatly affects the degree of dehalogenation achieved. Second, the growth and decay of biomass from soluble carbohydrate plays a significant role in reductive dehalogenation. Finally, the carbohydrate delivery strategies used (periodic versus batch addition and the time interval between periodic addition) greatly affect the degree of dehalogenation that can be obtained with a given amount of added carbohydrate.     

生物活性炭法深度处理纺织废水二级出水中生物活性的研究

采用上流式曝气生物活性炭法处理碱减量印染废水二级生物处理出水,利用TTC-脱氢酶活性(DHA)法监测反应器内DHA生物活性分布.研究发现反应器内生物炭表面附着生物膜活性较高,特别是反应器上部生物碳粒同样具有较高的DHA活性,这与反应器运行一年多能够保持对COD、色度和UV等较高去除率有一定关系.还研究了活性炭吸附、反应器反冲洗对DHA活性的影响.本研究为曝气生物活性炭法有效去除印染碱减量废水中难降解有机物提供了一定的理论依据.     

冷却水缓蚀阻垢剂的绿色化研究进展

简要介绍了工业循环冷却水缓蚀阻垢剂的发展概况 ,阐述了低磷聚合物及新型无磷缓蚀阻垢剂的研究现状 ,并指出了今后的发展方向。     

一种新型环境矿物材料在废水处理中的应用研究

实验研究表明 ,磷矿石作为一种新型环境矿物材料对重金属离子工业废水具有较好的处理效果 ,且自身具有显著的优点。采用分级处理的方法以及磷矿石的合适用量可以使处理后的工业废水达到排放标准甚至饮用标准 ,同时 ,由于磷矿石去除重金属离子速度快 ,在瞬间即可发生作用 ,使得利用动态法进行工业废水的连续处理成为可能 ,而且不会产生二次污染 ,具有工艺应用意义     

生物活性炭法深度处理纺织废水二级出水中生物活性的研究

采用上流式曝气生物活性炭法处理碱减量印染废水二级生物处理出水，利用TTC-脱氢酶活性（DHA）法监测反应器内DHA生物活性分布。研究发现反应器内生物炭表面附着生物膜活性较高，特别是反应器上部生物碳粒同样具有较高的DHA活性，这与反应器运行一年多能够保持对COD、色度和UV等较高去除率有一定关系。还研究了活性炭吸附、反应器反冲洗对DHA活性的影响。本研究为曝气生物活性炭法有效去除印染碱减量废水中难降解有机物提供了一定的理论依据。