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931.
A field study was carried out in the Lagoon of Venice (north-east Italy) with the aim of evaluating the potential use of lysosomal destabilisation as a biomarker of anthropogenic stress in the autochthonous mussel Mytilus galloprovincialis. Two different approaches were adopted in biomonitoring six sites in the Lagoon, evaluating indigenous populations of mussels and organisms transplanted from a reference site and checked at several points in time. Lysosomal membrane stability was investigated by means of two tests: neutral red retention assay (NRRA) for evaluating haemocyte lysosomes and lysosomal latency test (LLT) for digestive cell lysosomes. Results indicate that the lysosomal response measured in haemocytes according to NRRA is a more valuable biomarker of anthropogenic stress in the framework both of passive and active biomonitoring in marine coastal environments. 相似文献
932.
1998年11月长江河口悬浮体粒度特征的空间分布 总被引:4,自引:0,他引:4
利用Cilas940L型激光粒度仪对1998年11月取自长江河口的46个悬浮体样品进行了粒度测试分析。结果表明,长江河口悬浮体粒度特征在空间上具有明显的变化。悬浮体粒度的平均粒径、分选系数、偏态和峰态等参数,以及粉砂和粘土级含最在河口区平面和垂向上的分布的变化部较为显著。悬浮体的粒度分布为非正态分布,表层悬浮体为双峰分布模式,底层悬浮体为双峰或三峰分布模式。重点探讨了长江河口悬浮体粒度变化的影响因素中的表层沉积物的再悬浮作用和悬浮细颗粒絮凝这两个主要的因素。对长江河口表层沉积物的再悬浮通量进行了估算,表明,不同区域的再悬浮作用存在较大的差异,拦门沙地区为主要的再悬浮发生区。 相似文献
933.
934.
视网膜视蛋白组成是动物识别光强与颜色视觉的基础,其会随着不同生长环境和发育阶段而发生变化。大菱鲆(Scophthalmus maximus)为重要的海水养殖鱼种,在发育过程中经历了从浮游生活到底栖生活的转变;生活习性的转变伴随着生存环境的变化,尤其是光照环境的变化。我们推测大菱鲆光照感知功能包括视蛋白种类及表达模式等,在不同阶段应有所不同,目前未见相关研究报道。本研究以1、4和9月龄大菱鲆为研究对象,通过qRT-PCR探查了不同阶段大菱鲆视蛋白基因表达的特征规律,通过分析三个发育阶段的视蛋白基因表达比例,推测鱼体光谱敏感性变化规律。结果表明,红视蛋白(LWS)基因表达量随鱼体发育逐渐降低,视紫红质(RH1)、紫外视蛋白(SWS1)和蓝视蛋白(SWS2)随鱼体发育表达量逐渐升高,而绿视蛋白(RH2)中高表达的RH2b1无显著变化。LWS表达比例由1月龄57.2%降至九月龄11.4%,RH2b1表达比例由1月龄29.9%升至九月龄73.3%。随着大菱鲆由早期浮游生活转入底栖生活,表达占主导地位的视蛋白,逐渐由LWS转变为RH2b1,其光谱敏感性可能由红色敏感向绿色敏感转变。大菱鲆视蛋白在不同发育阶段表达的特征变化引发的光谱敏感性变化,可认为是其对不同光环境的适应策略。 相似文献
935.
An integration of sediment physical, chemical, biological, and toxicity data is necessary for a meaningful interpretation of the complex sediment conditions in the marine environment. Assessment of benthic community is a vital component for that interpretation, yet their evaluation is complex and requires a large expenditure of time and funds. Thus, there is a need for new tools that are less expensive and more understandable for managers. This paper presents a benthic biotope index to predict from physical and chemical variables the occurrence of macrobenthic habitats. Parameters such as sediment type, organic matter, depth, and hydrodynamic parameters were selected, through a discriminant analysis, to compute the index. Other authors have used multivariate methods to determine the benthic biotopes for Sado Estuary. The index proved to be a valid tool to classify and assess the spatial patterns of benthic habitat and to synthesize stress biotope gradients. 相似文献
936.
937.
黑Jun生态生长效率周年变化的研究 总被引:1,自引:0,他引:1
于1983年12月-1984年5月和1990年6月-1991年1月以中国科学院海洋研究所生物培育楼养殖黑Jun为材料,进行黑Jun周年的摄食-生长实验,以探讨其生态生长效率变化规律。结果表明,作为冷温性鱼,黑Jun在4.0-27.3℃水温条件下都有摄食;平均日摄食量为2.4-10.0g,相对体重的百分比为1.1%-4.4%,这二者的周年变化趋势基本一致;平均体重日增长量以4,6,7月和10-12月 相似文献
938.
939.
Response of antioxidant systems to copper in the gills of the clam Ruditapes decussatus 总被引:1,自引:0,他引:1
Copper (Cu) is an essential element for biological systems, however, when present in excess, is toxic. Metallothioneins can play an important role in Cu homeostasis and detoxification. Moreover, Cu can catalyse the production of toxic hydroxyl radicals that cause lipid peroxidation but defence systems in the cells can limit the oxidative damage. The present study was performed to investigate the effect of three Cu concentrations (0.5, 2.5 and 25 microg l(-1)) on the response of antioxidant enzyme activities (superoxide dismutase (SOD), catalase (CAT), selenium-dependent glutathion peroxidase and total glutathion peroxidase), total proteins, metallothioneins (MT), malondialdehyde (MDA) concentrations in the gills of the clam, Ruditapes decussatus. The activity of antioxidant enzymes and total proteins, MT and MDA concentrations were measured in the gills of the clams after 1, 3, 7, 14, 21 and 28 days of Cu exposure. Results indicate that Cu only induces an imbalance in the oxygen metabolism during the first week of Cu exposure due to a decrease in mitochondrial SOD and CAT, selenium-dependent and total glutathion peroxidase activities. Cu also causes lipid peroxidation, measured by the MDA formation, that was Cu dependent. In the gills of clams exposed to 25 microg Cu/l, the excess of Cu triggers the induction of MT synthesis after 3 days of exposure. 相似文献
940.
Minier C Lelong C Djemel N Rodet F Tutundjian R Favrel P Mathieu M Leboulenger F 《Marine environmental research》2002,54(3-5):455-459
The multidrug resistance (MDR) mechanism corresponds to a defence system relying on the expression of high molecular membrane proteins that can actively lower the intracellular concentration of a wide variety of toxins, thus maintaining them below their toxic level. Using RT-PCR, expression levels of a gene belonging to the class I of mammalian mdr genes, has been assessed in different developmental stages of the oyster Crassostrea gigas. While no expression was found in the oocyte or the trocophore stage, a rise of mRNA content was observed from the veliger stage to the juvenile stage, thus indicating the induction of the system as the animal is developing in the environment. The incubation of gill fragments in the dye rhodamine B and subsequent measurements of intracellular fluorescence using a microplate reader indicates that the system can effectively decrease the accumulation of the test compound in a competitive manner with known inhibitors or environmental contaminants as observed in vertebrate cells. The oyster MXR system is thus becoming active in adult oyster and could be of importance in environmentally contaminated areas. 相似文献