纳米颗粒与生物大分子的相互作用及其生物毒性机制

纳米颗粒已得到广泛的应用,同时其潜在的毒性及生物学效应也引起了广泛的关注。许多文献证实纳米颗粒对生物体具有毒性作用,但在分子水平上对其毒性机制的研究较少。本文对近年来纳米颗粒与生物大分子相互作用的最新研究进行了综述,包括纳米颗粒与蛋白质、脂类、核酸等生物分子间的相互作用。     

环境因子对小麦体内镉的生物毒性和植物络合素合成的影响

采用水培方式,研究了不同环境因子对小麦体内Cd的生物毒性与植物络合素(PCs)合成的影响.结果表明,Cd胁迫对小麦产生明显的毒害效应,并显著诱导根合成PCs;pH、Ca和S对小麦体内Cd的吸收和生物毒性具有不同程度的影响,根中PCs的诱导量与Cd的生物毒性变化表现一致;供磷减轻了Cd胁迫的生物毒性,根中PCs的诱导量也显著降低;镁对Cd胁迫的生物毒性影响甚微,根中PCs的诱导量和Cd的吸收量均未见明显变化.本实验结果证明Cd对PCs的诱导能力与植物体内Cd的毒性之间存在一定的相关关系,可将PCs作为Cd胁迫的生物标记物.     

蓝藻水花的毒性及其生物控制

蓝藻水花的毒性及其生物控制由文辉（上海华东师范大学环境科学系上海２０００６２）近几十年来,由于城市和工业的迅速发展以及农业上广泛施用化肥,大量污水排入水体中,使很多水体富营养化。在富营养化水体中,浮游植物群落发生了以甲藻和硅藻为主转变为以绿藻和蓝藻为...     

小球藻生物富集锌、镉机制的研究

藻类对许多重金属具有较强的生物富集能力,小球藻（Chlorella spp.)分别在不同系列Zn^2 ,Cd^2 浓度下培养8d间隔2d,测定小球藻的生物量及Zn和Cd的含量。结果表明,小球藻随水体中Zn^2 和Cd^2 的浓度不同,在重重金属水体中暴露时间不同,具有不同的富集速率和能力。     

不同营养状态下方斑东风螺的镉生物积累及毒性

采用室内模拟方式,研究了方斑东风螺在饥饿及摄食饵料分别为贻贝和沙蚕3种情况下暴露于水体镉(Cd2+,50 μg·L-1)10周后的存活、生长、螺体Cd蓄积及有关毒性效应参数的变化.结果表明:长期饥饿与同时水体Cd暴露降低了方斑东风螺的成活率,且螺体糖原被最大程度动用,摄食有助于螺体抵抗Cd毒性;方斑东风螺肝胰脏DNA受损伤后在摄食状态下随时间延长均有不同程度的自我修复能力,但长期禁食使螺的DNA完整性降低且不能恢复;饥饿引起方斑东风螺体组织萎缩,并导致Cd蓄积与金属硫蛋白(MT)含量升高,摄食螺因体质量增加的稀释作用而具有较低的Cd蓄积与MT含量;摄食贻贝的方斑东风螺较摄食沙蚕有更快的生长率和更低的Cd浓度.表明饥饿加剧了Cd对方斑东风螺的毒性;不同饵料对方斑东风螺的生长有显著影响,并间接影响螺体Cd蓄积、MT诱导和糖原消耗.应用方斑东风螺等海洋腹足类作为环境监测指示种时应考虑栖息地食物丰度和饵料类型等的影响.方斑东风螺高密度工厂化养殖中应注意合理投饵并定期监测海水Cd浓度.     

有机物料对土壤镉形态及其生物有效性的影响

采用盆栽试验,研究了淹水种稻条件下添加猪粪和泥炭对红壤和潮土中内源和外源Cd形态及其生物有效性的影响。结果表明,土壤中内源Cd在各形态之间的分布比较均匀;添加外源Cd时Cd主要分布于交换态,从分蘖期到成熟期,内源Cd交换态普遍升高,添加外源Cd时交换态普遍降低。有机物料对内源Cd交换态的影响不显著,但当添加外源Cd时则对交换态有显著影响,在不添加外源Cd的条件下,有机物料普遍促进水稻根系对Cd的吸收。在添加外源Cd的条件下,有机物料普遍抑制水稻根系对Cd的吸收,猪粪的抑制效果强于泥炭,水稻根系对Cd与Fe的累积呈显著抑制作用。     

泉州市散白蚁的活动、分飞、危害及其防治

据平正明、何秀松 2 0 0 0年在《中国白蚁志》[1 ]上发表的文章 ,已知我国目前有散白蚁 ( Reti-culitermes) 1 1 1种 ,它分布在我国大江南北的广大地区 ,南起海南省的尖峰岭 (北纬 1 8.5°) ,北至辽宁省的丹东 (北纬 4 0 .1°)都有其活动危害的足迹。福建目前已知的散白蚁也有 1 9种 (黄复生 1 989年 ) [2 ] ,占全国散白蚁种类的 1 1 .1 2 %。泉州 (东经 1 1 7°35′- 1 1 9°0 5′、北纬 2 4°2 3′- 2 5°50′) ,在福建的东南沿海 ,依山面海 ,属海洋性季风气候 ,湿润多雨 ,四季常青 ,年平均气温为 1 8℃ - 2 1℃ ,年降雨量达 1 0 0 0 - 1…     

咖啡天牛的生存对策,防治策略及其应用

通过分析咖啡旋皮天牛Ａｃａｌｏｌｅｐｔａ ｃｅｒｖｉｎｕｓ 和咖啡灭字虎天牛Ｘｙｌｏｔｒｅｃｈｕｓ ｑｕａｄｒｉｐｅｓ Ｃｈｅｖｒ;的生态对策,种间竞争策略,并结合有害生物综合管理理论,咖啡林生态系统的特性,咖啡天牛的发生特点,提出了咖啡天牛的防治策略。     

ZnO和CuO纳米颗粒对废水生物处理的影响及缓解毒性的研究进展

ZnO和CuO纳米颗粒(nanoparticles, NPs)在研究、医学和工业等领域的广泛使用,已引起人们对其生物安全性的忧虑。相关学者已在污水处理系统中检测到ZnO NPs和CuO NPs,由于其独特的理化性质,低含量NPs就对微生物群落结构和生长代谢产生毒性,进而影响污水脱氮的稳定运行。本文综述了ZnO NPs和CuO NPs对生物脱氮系统中相关功能细菌的毒性及机制,并总结了通过调节水环境因素(如pH值、离子强度、离子类型和天然有机物等)缓解ZnO NPs和CuO NPs的细胞毒性,以期为今后缓解和应急调控金属纳米颗粒(metal oxide nanoparticles, MONPs)对污水处理系统的冲击提供理论基础和支撑。     

亚致死剂量乙草胺对蚯蚓的毒性效应及敏感生物标记物

本研究以赤子爱胜蚓为受试生物,采用外源添加污染物的方法,将受试生物暴露于含亚致死剂量乙草胺(添加浓度分别为1、2、4、8 mg·kg-1)的土壤中7d,研究蚯蚓生长抑制率、细胞色素P450同工酶(CYP1A2、2C9和3A4)活力及代谢组学对乙草胺的响应,从个体、酶、小分子标记物3个层次探讨亚致死剂量乙草胺对蚯蚓的毒性...     

Architectural and biochemical changes in embryonic tissues of maize under cadmium toxicity

Heavy metals greatly alter plant morphology and architecture, however detailed mechanisms of such changes are not fully explored. Two experiments were conducted to investigate the influence of cadmium (CdCl₂·2.5H₂O) on some germination, morphological, biochemical and histological characteristics of developing embryonic tissue of maize. In the first experiment, maize seeds were germinated in increasing levels of CdCl₂ (200–2000 μm ) in sand and measurements were taken of changes in germination and seedling development attributes. Based on these parameters, 1000 μM CdCl₂ was chosen for detailed biochemical and histological measurements. In the second experiment, seeds were germinated in Petri dishes and supplied with 0 (control) or 1000 μM CdCl₂ (Cd‐treated). Radicle, plumule, coleoptile and coleorhiza were measured for biochemical and histological changes. The highest amount of Cd was in the coleorhiza and radicle. Free proline, soluble sugars, anthocyanin, soluble phenolics, ascorbic acid, H₂O₂ and MDA were significantly higher in coleorhizae, followed by the coleoptile, radicle and plumule. Although the radicle and coleorhiza were relatively poor targets of Cd than the other tissues, Cd stress reduced cortical cell size and vascular tissues, and deformed xylem and phloem parenchyma in all plant parts. In conclusion, the main reason for reduced germination was the influence of Cd on architecture of the coleorhiza and coleoptile, which was the result of oxidative stress and other physiological changes taking place in these tissues.     

The initial pathogenesis of cadmium induced renal toxicity

The novel application of magic angle spinning 1H NMR spectroscopy, coupled with pattern recognition techniques, has identified biochemical changes in lipid and glutamate metabolism that precede classical nephrotoxicity. These changes occurred in the bank vole (Clethrionomys glareolus) after chronic dosing, at a low level of exposure and at a renal Cd(2+) concentration (8.4 microgram/g dry wt) that was nearly two orders of magnitude below the WHO critical organ concentration (200 microg/g wet wt). These early stage effects of Cd(2+) on the biochemistry of renal tissue may reflect adaptation mechanisms to the toxic insult or the preliminary stages of the toxicological cascade.     

The vascular endothelium as a target of cadmium toxicity

Cadmium (Cd) is an important industrial and environmental pollutant that can produce a wide variety of adverse effects in humans and animals. A growing volume of evidence indicates that the vascular endothelium may be one of the primary targets of Cd toxicity in vivo. Studies over the past 20 years have shown that Cd, at relatively low, sublethal concentrations, can target vascular endothelial cells at a variety of molecular levels, including cell adhesion molecules, metal ion transporters and protein kinase signaling pathways. The purpose of this review is to summarize the results of these recent studies and to discuss the implications of these findings with regard to the mechanisms of Cd toxicity in specific organs including the lung, liver, kidney, testis and heart. In addition the possible roles of the vascular endothelium in mediating the tumor promoting and anticarcinogenic effects of Cd are discussed.     

Aspects of the biochemical toxicology of cadmium.

Cadmium, in addition to producing a variety of toxic manifestations, is known to accumulate in certain "target" organs which include liver and kidney where histological and functional damage becomes apparent. The daily intraperitoneal injection of cadmium chloride for 21 or 45 days stimulated the activities of hepatic pyruvate carboxylase, phosphoenolpyruvate carboxykinase, fructose-1, 6-diphosphatase and glucose-6-phosphatase elevated blood glucose and urea, and lowered hepatic glycogen in rats. Whereas chronic Cd treatment failed to alter adenosine-3', 5'-monophosphate phosphodiesterase (PDE) activity, cyclic AMP (cAMY and the activity of basal and fluoride-stimulated forms of hepatic adenylate cyclase (AC) were markedly increased. However, the cAMP binding to hepatic protein kinase was decreased as was the kinase activity ration. An acute dose of Cd decreased hepatic glycogen content and increased blood glucose, serum urea, and hepatic cAMP. Chronic exposure to Cd induced adrenal hypertrophy and augmented adrenal norepinephrine and epinephrine as well as the activity of adrenal tyrosine hydroxylase. This treatment decreased prostatic and testicular weights of mature rats. Although cAMP as well as AC activity of the prostate gland were reduced, cAMP binding to the prostatic protein kinase was increased as was the activity of the cAMP-dependent form of the enzyme. Testicular AC and PDE activities, however, were stimulated, although cAMP remained unaffected. Whereas the activities of the cAMP-dependent and the independent forms of testicular protein kinase were significantly depressed, the binding of cAMP to protein kinase from testes of Cd-treated rats was not affected. In most cases, the observed metabolic alterations persisted up to 28 days on cessation of Cd administration. Subacute Cd treatment suppressed pancreatic function as evidenced by lowered serum immunoreactive insulin (IRI) in presence of hyperglycemia, as well as by partial inhibition of phentolamine-stimulated increases in serum IRI. Although chronic Cd treatment failed to alter the concentration of brain stem norepinephrine and cerebrocortical acetylcholine esterase activity, serotonin levels of brain stem were depressed and the concentration of striatal dopamine and cerebrocortical acetylcholine were significantly elevated when compared with the values seen in control nonexposed animals.     

生物技术在重症急性呼吸综合征防治中的应用前景

同重症急性呼吸综合征(SARS)的斗争是全世界所面临的紧迫任务,而人类最终战胜SARS则必须依靠科学技术。现代生物技术在SARS病原体的发现过程中已经起到了举足轻重的作用,本就生物信息学、生物学诊断检测技术、疫苗技术、抗体技术、反义技术和RNA干扰以及生物技术药物在SARS防治中的应用前景作一简要介绍。     

安普贴薄膜用于防治褥疮的临床效果观察

目的：探讨用安普贴薄膜预防和治疗褥疮的临床效果。方法：将126例卧床的病人随机分成2组,两组均安置在气垫床上2～3小时翻身一次,观察组使用安普贴薄膜,对照组给予褥疮的常规护理,烤灯及换药,观察临床效果。结果：观察组的效果明显优于对照组。结论：时卧床病人使用安普贴薄膜对褥疮的早期治疗和预防有显著效果。     

Seed priming with methyl jasmonate mitigates copper and cadmium toxicity by modifying biochemical attributes and antioxidants in Cajanus cajan

Contamination of agricultural soils with heavy metals (HMs) has posed major threat to the environment as well as human health. The aim of this study was to appraise the efficiency of key-antioxidant enzymes in enhancing plants’ tolerance to HMs (heavy metals) like copper (Cu) and Cadmium (Cd), under the action of methyl jasmonate (Me-JA) in Cajanus cajan L. Seeds of C. cajan treated with Me-JA (0, 1 nM) were discretely subjected to noxious concentrations of Cu and Cd (0, 1, 5 mM) and raised for 12 days under controlled conditions in plant growth chamber for biochemical analysis. In contrast to Cd, Cu triggered oxidative stress more significantly (44.54% in 5 mM Cu increase in MDA as compared to control) and prominently thereby affecting plants’ physiological and biochemical attributes. By activating the antioxidant machinery, Me-JA pre-treatment reduced HMs-induced oxidative stress, increased proline production, glutathione (41.95% under 5 mM Cu when treated with 1 nM Me-JA treatment) and ascorbic acid content by 160.4 % under aforemtioned treatments thus improving the redox status. Thus, in light of this our results put forward a firm basis of the positive role that Me-JA might play in the mitigation of oxidative stress caused due to HMs stress by stimulating antioxidant defense system leading to overall improvement of growth of C. cajan seedlings.