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1.
镉对褐菖You金属结合蛋白的诱导 总被引：1，自引：1，他引：1
金属结合蛋白是一类富含半胱氨酸，不含芳香族氨基本以和组氨酸的低分子量蛋白质。在紫外２５４ｎｍ处具强的吸收。用不同剂量的氯化诱导褐菖Ｙｏｕ，通过凝胶过滤从褐菖Ｙｏｕ肝脏提取金属结合蛋白，并测定其结合的镉以及硫醇含量与紫外２５４ｎｍ处的吸收值。结果表明，镉能诱导褐菖Ｙｏｕ金属结合蛋白的合成。 相似文献
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紫球藻两种藻红蛋白特性的比较研究——γ亚基在稳定藻红蛋白结构方面的作用 总被引：2，自引：4，他引：2
从紫球藻中分离纯化两种藻红蛋白（B－藻红蛋白和b-藻红蛋白），对它们的吸收光谱和电泳图谱进行比较研究。结果表明，尽管电泳图谱与文献报道的相同，但b-藻红蛋白的吸收光谱与文献报道的有较大的差别，表现在本研究发现b-藻红蛋白在545nm处有一吸收峰。在565nm处仅有一个吸收肩峰，而不是文献中报道的在545nm和565nm无前独立的吸收峰。通过比较B－藻红蛋白和b-藻红蛋白在不完全变性条件下的电泳图谱，发现B－藻红蛋白比b-藻红蛋白要稳定的多，进一步分析认为这主要是因为B－藻红蛋白含有γ亚基，而b-藻红蛋白不含有γ亚基，因为此为γ亚基有稳定分子的作用。 相似文献
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三角褐指藻（Phaeodactylum tricornutum）和翦股颖草属禾草（A-grostis capillaris）经过处理后再用液相层析法从中提取一种金属结合多肽，极谱分析表明不同的镉结合多肽具有不同的稳定性，金属结合与金属硫蛋白不同，在电位--1.7V附近未出现氧催化峰，金属硫蛋白以及从单胞藻和禾草中提取的多肽在极谱测定过程中都在电位-520mV和-930mV附近出现双峰，在-520mV处，半波电位显示了单个镉硫醇键的还原，在-930mV处的峰是由于镉和硫多齿螯合的还原，因此这通常可用以鉴定镉螯合物。在镉浓度为5umol/dm^3和10umol/dm^3时-930mV的峰高与镉浓度之间存在着对应关系。 相似文献
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钝顶螺旋藻藻胆蛋白的提取及其特性初报 总被引：3，自引：0，他引：3
作者采用细胞破碎,等电点沉淀的方法,提取、分离螺旋藻的藻胆蛋白,并在藻胆蛋白中检测到17种氨基酸。文中还研究了在500～700nm波长范围内不同外界因子对藻胆蛋白理化特性的影响,结果表明:(1)不同的pH值,藻胆蛋白液颜色及其吸收光谱的形状和强度不同。当pH为4和5.5时,藻胆蛋白液呈绿蓝色,吸收峰在625nm处,而pH为7,吸收峰移至600nm处,溶液呈蓝色,pH为8.5和10时,出现双峰,分别位于600nm和650nm处。(2)藻胆蛋白热稳定性差,吸收光谱强度随着温度升高而迅速下降。温度在30℃以下,藻胆蛋白较稳定。(3)藻胆蛋白对光照较敏感。(4)10％乙醇、10％蔗糖、1％NaCl对藻胆蛋白均有不同程度的增色效应。 相似文献
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海洋单细胞藻对紫外吸收的比较研究 总被引：4，自引：0，他引：4
用日本岛津UV-260分光光度计,对9种海洋单细胞藻的紫外吸收变化进行了研究.结果表明:(1)9种海洋单细胞藻的吸收峰的波长均在280nm以下,它们相应的波长范围在252.8～266.4nm之间,高低相差仅为13.6nm;(2)按吸收峰值从大到小排列依次为:盐藻＞扁藻＞小球藻＞塔胞藻＞角毛藻＞三角褐指藻＞新月菱形藻＞金藻3011＞金藻8701,呈现明显的规律性变化,即:绿藻门＞硅藻门＞金藻门;(3)在UV-B(280～320nm)波段,9种海洋单细胞藻的吸收度均随波长的增加呈现逐渐下降的趋势,而吸收度的大小排列次序同吸收峰值完全一致,同样表现出绿藻＞硅藻＞金藻的规律. 相似文献
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为探讨海水水质监测的简便可行方法,对渤海、北黄海、胶州湾、东海、长江口、南海及珠江口几百个海水样品紫外扫描发现,不同海区海水紫外吸收约在200～220nm之间。其中渤海、北黄海与胶州湾海水样品在208～210nm之间,而东海、长江口、南海及珠江口水样在205nm附近。海水紫外吸收吸光度与高锰酸钾法测COD值之间具有良好的线性关系。所以提出了用紫外分光光度法测定海水COD值的方法,发现紫外分光光度法与碱性高锰酸钾法测定海水COD值无显著性差异,可以满足快速监测的需要。 相似文献
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缢蛏超氧化物歧化酶的纯化和性质研究 总被引：7，自引：0，他引：7
经加热和硫酸铵分级沉淀，DE-52柱层析和SephadexG-100凝胶过滤，从缢蛏中分离纯化铜锌超氧化物歧化酶（Cu,Zn-SOD)，并对其理化性质进行分析鉴定，结果获得该酶的比活力为3794.9(U/mg)，提纯倍数为607.7.聚丙烯酰胺凝胶电泳蛋白带与活性带相对应，等电点为5.8.该酶是由两个相同的亚基组成的二聚体，相对分子质量为29.6kD。紫外吸收峰在275nm处，KCN和H2O2能抑制酶活性，而Tsuchi-hashi液对酶活性没影响，该酶的最适pH为6-10，最适温度为37℃，热稳定性在63℃以下。 相似文献
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本文以野生型和突变型龙须菜为材料,测定了完整藻体的室温吸收光谱、77K低温荧光发射光谱和叶绿素诱导荧光动力学曲线.野生型(Wt)和黄色突变体(Ye100)的室温吸收光谱有435、498、540、566、618、640和680nm7个吸收峰;绿色突变体Gr180和Gr184则只有除540nm以外的6个吸收峰.3种突变体的藻红蛋白含量均比野生型少,两种绿色突变体的藻蓝蛋白含量相对有所增加,别藻蓝蛋白含量变化不明显.77K低温荧光发射发谱(激发光分别为436、540和580nm)的结果表明:在发射峰的波长上,4种材料没有明显的区别,但Wt中PE吸收的光能传递效率比较低.叶绿素诱导荧光动力学曲线显示Wt的光系统Ⅱ活性、光系统Ⅱ原初光能转化效率及光合碳代谢活性都高于突变体. 相似文献
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海水钝顶螺旋藻富硒及其含硒藻蓝蛋白的研究 总被引：1，自引：0，他引：1
研究了亚硒酸钠梯度浓度对海水钝顶螺旋藻Spirulina platensis生长及藻胆蛋白含量的影响,对含硒藻蓝蛋白进行分离纯化,得到含硒藻蓝蛋白纯品。结果表明,硒添加浓度小于100mg.L-1时,对藻体生长有一定的促进作用,其生物量、藻蓝蛋白和别藻蓝蛋白含量有增加,藻体硒含量及富硒系数明显高于文献报道的相似条件下的淡水螺旋藻;纯化的含硒藻蓝蛋白溶液在弱光照、低温、pH4—8的范围内稳定性较好;含硒藻蓝蛋白的光谱特性与藻蓝蛋白相比几乎没有差异,紫外与可见光吸收光谱特征吸收峰在280nm和620nm,荧光激发峰在558nm,室温条件下最大荧光发射峰在655nm,说明海水钝顶螺旋藻富集硒后及海水的胁迫对其藻蓝蛋白的光谱特性没有明显影响。 相似文献
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During recent years laboratory studies have demonstrated the presence of metallothionein in several species of teleosts.1–3 The role of metallothionein (MT) in protection against cadmium toxicity has been investigated by exposing fish to high levels of cadmium in the water.4–6 So far, however, few field studies have focused on the existence of MT and its role in subcellular distribution of cadmium.7 In the present study the synthesis of MT as a possible mechanism by which perch adapt to cadmium contamination was investigated in a wild population of perch. An increased MT content of perch liver was found to correlate to an increase in cadmium present in the liver. 相似文献
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J. del Ramo A. Torreblanca M. Martínez A. Pastor J. Díaz-Mayans 《Marine environmental research》1995,39(1-4)
Metallothionein (MT) has been proposed as a specific biochemical probe for metal exposure of aquatic organisms. It is recognized that its usefulness as a monitoring tool depends on the full understanding of its function and on the possibility of measuring its concentration in tissues. Therefore the study of MT in crustaceans is interesting from two different points of view: the need to understand mechanisms associated with the toxicology of metals, and the potential use of this protein for monitoring metal-contamined environments. Several methods have been developed for quantitative measurements of MT in biological samples. Immunochemical and electrochemical procedures are reliable techniques but they require sophisticated equipment and highly trained staff. In the present work, modifications to the silver-saturation method have been developed for the quantitative determination of MT in crustacean tissues, estimating silver concentrations by flame in an atomic absorption spectrophotometer. Cadmium and MT were measured both in Artemia and Procambarus clarkii after sublethal exposure to cadmium. An increase in MT content was recorded in crustacean tissues after 12 h of cadmium exposure. A high responsiveness was found in MT induction by cadmium in the two crustaceans and there was a clear relationship between cadmium concentration in water and MT levels in tissues. The silver-saturation assay may be a rapid assay technnique for biomonitoring purposes. 相似文献
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Previous experiments demonstrated that exposure of mummichog to cadmium (Cd) in combination with benzo[a]pyrene (BaP) caused a higher mortality than would be expected from simple additive effects. Experiments are described here that investigated whether BaP exposure inhibits the induction of metallothionein (MT), a major detoxifying protein for Cd, or if reactive BaP metabolites compete with Cd for binding sites on MT. Fish were injected with or without BaP (18 mg/kg) in combination with a low (1 mg/kg) or high (3.2 mg/kg) dose of Cd, and in one treatment BP was dosed 4 days after Cd. The results showed a rapid induction of MT to 1.5 mg/g wet weight liver, 1 day after injecting the low Cd dose. Simultaneous BaP exposure significantly delayed the induction of MT, for both low and high Cd doses, and BaP temporarily lowered the induced MT concentration when dosed 4 days after induction by Cd. To test if binding of BaP metabolites to MT reduces the detoxification potential for Cd, microsomes of CYP1A-induced fish were incubated with MT and radiolabeled BaP. Active metabolism of BaP was observed by high-performance liquid chromatography analysis, but no association of BaP metabolites with MT was found. Neither could this be demonstrated in vivo, in liver MT isolated from mummichog dosed with 3H-BaP and Cd. These results suggest that increased toxicity of Cd in combination with BaP exposure is likely to be caused by inhibited MT synthesis, rather than by interference of BaP metabolites with Cd binding on MT. 相似文献
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INTRODUCTIONATislowKWCys-rich(aboutonethird)metal-bindingprotein,lackofaromaticaminoacidresidues.AThasbeenfoundinkidneysandliversofmanymammals,andalsoininvertebrates,microorganismsandplants.ThepresenceofanAT-likeproteinhasbeenfoundinanumberofaquaticorganisms,includingtheplaice(Overnelletal.,1977),rock-fish(Olafsonetal.,1974),goldfish(Marafant,1976),andcrabandshrimp(Olafsonetal.,1979).AThasbecomethesubjectofgreatInterestinrecentyearsduetotheirwideexistenceandmetalaffinity.Scientistsha… 相似文献
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苯并芘对褐菖鲉肝细胞DNA交联的影响 总被引：2，自引：0，他引：2
以褐菖鲉（Sebastiscus marmoratus）为实验材料,设定苯并芘[B（a）P]的注射剂量梯度分别为0.00、0.05、0.50、5.00 mg/kg,分别于实验的第0、3、6天对每一条鱼进行腹腔注射,于第1、4、7天取样,测定胆汁中的B（a）P及其代谢物含量.采用荧光检测法检测B（a）P染毒后褐菖鲉肝细胞DNA-DNA交联（DDC）交联系数的变化,并用KC l-SDS沉淀法检测DNA蛋-白质交联（DPC）交联系数的变化.结果表明：（1）经注射染毒后鱼体胆汁中的B（a）P及其代谢物含量蓄积程度存在着明显的剂量效应和时间效应;（2）B（a）P的注射剂量分别为0.05、0.50 mg/kg时各时间点褐菖鲉肝细胞DDC交联系数均无显著增大（p〉0.05）,在5.00 mg/kg剂量组,随着时间延长DDC交联系数逐渐增大,第4天即有显著差异（p〈0.05）,第7天差异极显著（p〈0.01）;（3）B（a）P诱导DPC的趋势与DDC类似,但0.5 mg/kg剂量组在第7天DPC交联系数即出现显著增大（p〈0.05）.这表明B（a）P对DPC的诱导高于DDC.这为进一步研究B（a）P的遗传毒性提供了依据,并为探讨B（a）P致癌的作用机理提供了新的信息. 相似文献
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Trish J. Lavery Catherine M. Kemper Ken Sanderson Christopher G. Schultz Peter Coyle James G. Mitchell Laurent Seuront 《Marine environmental research》2009,67(1):1-7
Metallothioneins (MT) concentration, renal damage, and bone malformations were investigated in 38 adult Tursiops aduncus carcasses to determine any associations with cadmium, copper, zinc, mercury, lead and selenium. Significantly higher concentrations of cadmium, copper, and zinc in the liver were observed in dolphins showing evidence of more advanced renal damage. No significant differences in metal or selenium concentrations in the liver were observed between groups differing in level of bone malformations. Some dolphins displayed evidence of toxicity and knowledge of metal toxicity pathways were used to elucidate the cause of these abnormalities. Two dolphins had high metal burdens, high MT concentrations, renal damage, and evidence of bone malformations, indicating possible severe and prolonged metal toxicity. One dolphin showed evidence of renal damage, but the lack of any other symptoms suggests that this was unlikely to be caused by metal toxicity. We recommend examining a range of metal toxicity symptoms simultaneously to aid in distinguishing metal toxicity from unrelated aetiologies. 相似文献
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Andrew D. Laurie 《新西兰海洋与淡水研究杂志》2013,47(5):869-877
Metallothionein (MT) is a protein found in most eukaryotes where its primary role is the regulation of homeostasis of the essential metals copper and zinc. MTs have an additional protective role through their binding of toxic metals such as cadmium and mercury. Increased expression of MT in response to harmful levels of these metals has been demonstrated for several aquatic species. In this study, the expression of MT in the liver tissue of the New Zealand common bully Gobiomorphus cotidianus was measured by quantifying MT mRNA. A statistically significant increase in MT expression was observed in fish exposed to copper for 48 h, but not those exposed to zinc. Field sampling of common bullies showed a wide variation in individual hepatic MT mRNA levels which did not correlate with fish age, sex, or sampling location. A comparison of two populations of common bullies from a polluted and a control site showed a two‐fold higher mean MT mRNA level in fish from the polluted site. Implications for using MT expression in the common bully as a bio‐monitoring tool are discussed. 相似文献
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Avianna F. Zhukovskaya Nina N. Belcheva Valentina S. Slobodskova Viktor P. Chelomin 《Ocean Science Journal》2012,47(3):189-195
Organisms have evolved a cellular response called stress protein response that increases their tolerance in adverse environmental conditions. Well known stress proteins that bind essential and toxic metals are metallothionein (MT). The scallop Mizuhopecten yessoensis is the most interesting organism because it is able to accumulate toxic cadmium in its digestive gland. However, in the tissue of the digestive gland of Mizuhopecten yessoensis MT (metallothioneins) have not been found. Eastern scallops, Mizuhopecten yessoensis, were collected from two locations ?? one clean and one polluted site. The concentrations of cadmium (Cd), copper (Cu) and zinc (Zn) were measured in the digestive gland. There was a significant increase in Cd concentrations in this studied tissue. We found that in the presence of cadmium Mizuhopecten yessoensis can induce high molecular proteins. The results of experiments have shown that Cd-binding ligands have a number of properties similar to MT: acetone and temperature stability; the ability to bind some metals, including Cd, Cu and Zn. Protein chromatography (FPLC, Superosa 12) from the digestive gland of scallop M. yessoensis has shown that cadmium is associated with high molecular weight Cd-binding proteins (72 kDa and 43 kDa). The major cadmium-binding protein 72 kDa is glycoprotein. In experiments we have demonstrated that Cd-binding proteins can be induced when there is cadmium exposure. The results of this study strongly suggest that the far eastern scallop Mizuhopecten yessoensis has a unique and well-developed system for the detoxification of heavy metals and it allows for biochemical systems to be maintained in a relatively stable manner in the presence of heavy metals. 相似文献