微囊藻毒素对鱼类的毒性效应

湖泊富营养化导致的蓝藻水华已成为国内外普遍关注的环境问题,它所带来的主要危害之一是产生的藻毒素对鱼类的影响。在已发现的藻毒素中,微囊藻毒素(microcystins,MCs)的分布广、毒性大、危害严重,而备受关注。阐述了MCs对鱼类的影响。微囊藻毒素能干扰胚胎的发育,降低孵化率,增加畸形率,影响存活率,胚胎孵化受微囊藻毒素影响还具有剂量依赖效应;野外室内实验均表明鱼类暴露于微囊藻毒素后不仅可在肝脏中富集还可在肌肉、肠道等组织器官中快速积累;对鱼类进行组织病理检测发现MCs可导致肝脏、肾脏、心脏、脑、鳃等组织受损;MCs在鱼体中的解毒过程可能开始于由谷胱甘肽S-转移酶催化的还原型谷胱甘肽的结合反应;MCs还可影响鱼类的生长、行为和血清生化指标,此外,还具有一定的免疫毒性。MCs的转运机制和分子作用机制以及在食物链中传递过程中对人类造成的潜在影响可能成为今后研究重点。     

一种检测微囊藻毒素LR诱导大鼠肾细胞凋亡的方法

微囊藻毒素(Microcystins)是一种具有生物活性的单环七肽毒素,主要由微囊藻产生。其中5个氨基酸为固定组成成分,另外2种氨基酸是可变的,由此衍生出众多的同类物,微囊藻毒素LR(Microcystin LR,MCLR)是其中具有代表性的一种。同位素示踪显示,静脉注射、腹腔注射和口服3种不同途径进入小鼠体内的125I-MCLR 70%以上分布在肝脏和肾脏,揭示这两个脏器是它的靶器官。本实验中采用正常大鼠的肾细胞来研究MCLR对细胞的影响,利用流式细胞仪PI/Annexin V双染色法检测MCLR能否引起细胞凋亡的改变,为进一步探讨MCLR对细胞的损伤及作用机制提供依据。     

鲤肝细胞抗氧化系统对微囊藻毒素毒性的反应

用10μg／L的微囊藻毒素LR(Microcystin—LR,MC—LR)处理鲤肝细胞培养物,检测鲤肝细胞抗氧化系统的6项指标。结果表明,MC—LR处理后活性氧(ROS)含量明显升高,还原型谷胱甘肽(GSH)含量迅速下降,超氧化物歧化酶(SOD)、过氧化氢酶(CAT)的活性明显升高,谷胱甘肽过氧化物酶(GSH—Px)活性在MC—LR处理15min后也有明显上升,但谷胱甘肽S-转移酶(GST)活性在MC—LR处理后没有明显变化。另外,还从氧自由基理论解释了微囊藻毒素造成鲤肝细胞损伤的可能机理。     

微囊藻毒素LR诱导大鼠肾NRK细胞Bax蛋白表达

近年来水体富营养化已成为一个全球性关注的问题,过量的氮、磷使藻类过度生长并产生水华。微囊藻毒素是蓝藻的一些属产生的次生代谢产物,在发生水华的水体中这类毒素普遍存在。微囊藻毒素产生的原因和作用目前还不是很清楚,然而它们对动物和人类都能产生极为严重的影响。     

微囊藻毒素LR对草鱼肝脏超微结构影响的研究

关于微囊藻毒素对哺乳动物的影响已有较多的研究,指出微囊藻毒素LR是一种作用于肝脏的极强环肽毒素,并能引起肝细胞超微结构的改变［‘］,但是有关该毒素对鱼类影响的报道却很少,作者采用腹腔注射微囊藻毒素的方法,确定其在鱼体内作用的靶器官,观察超微结构的组织病理变化,并与对哺乳动物作用的结果相比较,进而探讨其对鱼类的致毒机理．回材料和方法微囊藻毒素LR由日本名城大学药学部提供。实验鱼为草鱼［Ctenopharyngodonidellus］,体重引一389,体长11—13cm,取自中国科学院水生生物研究所养殖场,在25℃下通以循环水驯化1周…     

微囊藻毒素LR对大鼠肝细胞Caspase-3酶活性的影响

水体富营养化的加剧,导致藻类水华频频发生。在全球由于藻类水华所产生的毒素,对人和动物都产生了极为严重的影响,使之成为日益突出的环境问题。其中危害最严重的n是微囊藻毒素(Micnocystin,MCYST)。而微囊藻毒素LR(LR)是微囊藻毒素中存在最为普遍且毒性作用最明显的一种,是MCYST的主要代表物。     

微囊藻毒素LR对大鼠淋巴细胞DNA的损伤效应

微囊藻毒素是一类具生物活性的单环七肽,是蓝藻的一些属产生的次生代谢产物,在发生水华的水体中这类毒素普遍存在。由于水华的普遍发生,微囊藻毒素的存在已是一个令人瞩目的问题。流行病学调查发现人群原发性肝癌、大肠癌发病率与饮水源中的微囊藻毒素有关。微囊藻毒素LR(MCLR)是微囊藻毒素中最常见的一种,由于它们的高急性毒性、强促癌活性以及与人类癌症发生的相关性使其受到全球的关注。DNA是生物体内的遗传物质,它的稳定对于生命体的正常繁殖与生长是至关重要的。     

微囊藻毒素对鱼类毒性影响的研究进展

微囊藻毒素 (Microcystins,简称MC)是一些有毒蓝藻,如微囊藻、颤藻和鱼腥藻等,产生的一种具有肝毒性的环状七肽。     

微囊藻毒素对鱼肝的毒性效应

研究已发现离体条件下微囊藻毒素时鱼的蛋白磷酸酶有极强的抑制作用’‘,”。有些研究证明活体致毒后细胞内蛋白的磷酸化水平增加,而毒素对生物活体致毒时蛋白磷酸酶的情况尚未见报道。本研究用鱼作为实验材料,活体致责时微囊藻毒素对鱼的蛋白磷酸酶及几种其它分子生态毒理学指标的影响。回材料与方法1．l微囊藻毒素L民根据HSYddd的方法卜‘,由日本SllWS湖水华样品中提取。l．2活体实验,对体重约259的鲫鱼腹腔注射LR,剂量分别为IO,50,100和400pg／kg。在lh和3h时取样,分别测定蛋白磷酸酶（Proteiphosphatase,简称PP）活性和…     

A bioassay for the simultaneous measurement of metabolic activity, membrane integrity, and lysosomal activity in cell cultures

The aim of this study was the development of an in vitro bioassay that combines several endpoints of general cytotoxicity for the screening of compounds or mixtures of compounds with potential bioactivity. The Alamar Blue assay was employed to assess metabolic activity, the Neutral Red assay was used for the assessment of membrane function and lysosomal activity, and the lactate dehydrogenase leakage assay was employed for the assessment of membrane integrity. Each assay was performed separately and in combination using a human fibroblast cell line (MRC-5). Three fungal secondary metabolites of different chemistry that affect different cellular targets were tested as model compounds: deoxynivalenol, enniatin B1, and 2-amino-14,16-dimethyloctadecan-3-ol. The obtained inhibitive compound concentrations for the assays performed separately and in combination were not significantly different (P < 0.05, n = 9). The combination of several cytotoxicity endpoints in a single assay increases the chance that potential bioactive/cytotoxic compounds are discovered during the screening of mixtures of natural compounds (e.g., extracts from fungal cultures or plants) when one endpoint fails and, at the same time, might give some basic information on the cellular target.     

Assessing the data quality in predictive toxicology using a panel of cell lines and cytotoxicity assays

In vitro cell viability assays have a central role in predictive toxicology, both in assessing acute toxicity of chemicals and as a source of experimental data for in silico methods. However, the quality of in vitro toxicity databanks fluctuates dramatically because information they contain is obtained under varying conditions and in different laboratories. The aim of this study was to identify the factors responsible for these deviations and thus the quality of the data extracted for predictive toxicology. Three cell viability assays measuring LDH leakage, WST-1 reduction, and intracellular ATP were compared in an automated environment using four mammalian cell lines: Caco-2, Calu-3, Huh-7, and BHK. Using four standard compounds--polymyxin B, gramicidin, 5-fluorouracil, and camptothecin--a significant lack of sensitivity in LDH assay compared with the other assays was observed. Because the viability IC(50) values for the standards were similar among the cell lines, the biochemical characteristics of different cell lines seem to play only a minor role, with an exception being the hepatocellular Huh-7 cell line. Toxicity assessment of new 1,2,4-triazoles revealed significant differences in their toxic potential, and the results indicate the same sensitivity profile among the assays as observed with the standard compounds. Overall, it can be argued that the assay selection is the most important factor governing the uniform quality of the data obtained from in vitro cell viability assays.     

Silibinin as a potential therapeutic for sulfur mustard injuries

Sulfur mustard (SM) is a vesicating chemical warfare agent causing skin blistering, ulceration, impaired wound healing, prolonged hospitalization and permanent lesions. Silibinin, the lead compound from Silybum marianum, has also been discussed as a potential antidote to SM poisoning. However, its efficacy has been demonstrated only with regard to nitrogen mustards. Moreover, there are no data on the efficacy of the water-soluble prodrug silibinin-bis-succinat (silibinin-BS).     

Effects of Nanoparticles on the Adhesion and Cell Viability on Astrocytes

In recent years, both pharmaceutical companies and manufacturing industries have expressed heightened interest in the potential applications of magnetic nanoparticles for therapeutic and technological purposes. Specifically, pharmaceutical companies seek to employ magnetic nanoparticles as carriers to facilitate effective drug delivery, especially in areas of the brain. Manufacturing industries desire to use these nanoparticles as ferrofluids and in magnetic resonance imaging. However, data concerning the effects of magnetic nanoparticles on the nervous system is limited. This study tested the hypotheses that nanoparticles can (1) inhibit adherence of astrocytes to culture plates and (2) cause cytotoxicity or termination of growth, both end points representing surrogate markers of neurotoxicity. Using light microscopy, changes in plating patterns were determined by visual assessment. Cell counting 4 days after plating revealed a significant decrease in the number of viable astrocytes in nanoparticle treated groups (p < 0.0001). To determine the cytotoxic effects of nanoparticles, astrocytes were allowed to adhere to culture plates and grow to maturity for 3 weeks before treatment. Membrane integrity and mitochondrial function were measured using colorimetric analysis lactate dehydrogenase (LDH) and 3-[4, 5-dimethylthiazol-2-yl]-2, 5-diphenyltetrazolium bromide (MTS), respectively. Treatment with nanoparticles did not significantly alter astrocytic LDH release (p > 0.05) in the control group (100% ± 1.56) vs the group receiving treatment (97.18% ± 2.03). However, a significant increase in MTS activity (p < 0.05) between the control (100% ± 3.65) and treated groups (112.8% ± 3.23) was observed, suggesting astrocytic mitochondrial uncoupling by nanoparticles. These data suggest that nanoparticles impede the attachment of astrocytes to the substratum. However, once astrocytes attach to the substratum and grow to confluence, nanoparticles may cause mitochondrial stress.     

Synthesis and anticancer potential of benzothiazole linked phenylpyridopyrimidinones and their diones as mitochondrial apoptotic inducers

A series of benzothiazole linked phenylpyridopyrimidinones (8a–g) and their diones (9a–g) have been designed, synthesized and evaluated for their anticancer activity. Among the series one of the conjugate 8b showed significant cytotoxicity against human cervical cancer cell line ME-180 with IC₅₀ value of 4.01 μM. This compound was tested on the cell cycle perturbations and DNA damage. Flow cytometry analysis revealed that the compound 8b showed drastic cell cycle perturbations due to concentration dependent increase in the sub-G0 phase in ME-180 cell line. DNA fragmentation and Hoechst staining reveals that this compound induced cell death by apoptosis. Further caspase-3 and loss of mitochondrial membrane potential suggested that the compound induces cell death by apoptosis.     

The effect of tributyltin on human eosinophylic leukemia EoL-1 cells

Organotin compounds are chemicals that are widely used in industry and agriculture as plastic stabilizers, catalysts and biocides. Many of them, including tributyltin (TBT), have been detected in human food and, as a consequence, detectable levels have been found in human blood. As organotin compounds were shown to possess immunotoxic activity, we focused our attention on the effect of TBT on the basic determinants of the function of eosinophils, i.e. cell adhesiveness and motility. We used human eosinophylic leukemia EoL-1 cells, a common in vitro cellular model of human eosinophils. Here, we demonstrate that TBT causes a dose-dependent decrease in the viability of EoL-1 cells. When administered at sub-lethal concentrations, TBT significantly decreases the adhesion of EoL-1 cells to human fibroblasts (HSFs) and inhibits their migration on fibroblast surfaces. Since the basic function of eosinophils is to invade inflamed tissues, our results indicate that TBT, and possibly other organotin compounds, may affect major cellular properties involved in the determination of in vivo eosinophil function. Paper authored by participants of the international conference: XXXIV Winter School of the Faculty of Biochemistry, Biophysics and Biotechnology of Jagiellonian University, Zakopane, March 7–11, 2007, “The Cell and Its Environment”. Publication costs were covered by the organisers of this meeting.     

半胱氨酸预防FCCP所致体外大鼠肝细胞损伤研究

ＦＣＣＰ作为质子传递型氧化磷酸化解偶联剂,是一种强力的ＡＴＰ合成抑制剂。８０μｍｏｌ／Ｌ的ＦＣＣＰ可在数分钟内使细胞内的ＡＴＰ耗竭。半胱氨酸可使ＦＣＣＰ引起的ＡＴＰ,氧消耗量和乳酸脱氢酶逸出率等改变恢复正常。半胱氨酸对ＦＣＣＰ的解毒作用是特异的和与剂量有关,而其他含巯基剂如：还原型谷胱甘肽和二硫苏糖醇（ＤＴＴ）则不能干扰ＦＣＣＰ对细胞线粒体功能的影响。