Trace metal-binding proteins in marine molluscs and crustaceans

Some marine invertebrates, such as the American oyster, Crassostrea virginica, the blue crab, callinectes sapidus and the American lobster, Homarusamericanus, concentrate trace metals in their tissues. The occurrence of metallothionein, a low molecular weight, sulfur-containing metal-binding protein, has been correlated with elevated levels of trace metals in these organisms. It is our hypothesis that, whilst metallothioneins are involved in the sequestration of elevated levels of trace metals, they primarily function in regulating normal metal metabolism. In this paper we describe recent field and laboratory experiments designed to examine how oysters, blue crabs and lobsters manage accumulated cadmium, copper and zinc. The possible rôles of metallothionein, as well as the tissue distribution of metals, are emphasized. Metallothioneins were found in all animals we examined; concentrations of metallothioneins and the the amount of bound trace metals are related to time of exposure. We have also demonstrated that the laboratory developed metallothionein models for blue crabs and lobsters may be useful in predicting the partitioning of trace metals in animals living in environments polluted with trace metals.     

Device for detecting and measuring activity of large marine crustaceans

A device for detecting and measuring the locomotor activity of large marine crustaceans in captivity is described. The sensor is essentially a simple galvanic cell, of which the electrolyte is the sea water in which the animal is maintained. A punched‐tape recording system used with the device is also described.     

Evaluation of acetylcholinesterase activity in several zooplanktonic crustaceans

Zooplankton are an essential component of the marine and estuarine food chains. The ecotoxicological risk to zooplanktonic communities, estimated through the use of the biomarkers, can be used as an early warning signal of a potential alteration of the ecosystem health. The aim of this project was to evaluate the potential use of several biomarkers (esterases, mixed function oxidases, porphyrins) in zooplanktonic organisms. The acetylcholinesterase activity (AChE) was determined in homogenates of whole organisms of 10 different zooplanktonic crustaceans. Mean activity of AChE was 10.05 micromol/min/g for Acartia margalefi; 3.30 for Acartia latisetosa; 79.70 for Siriella clausi; 49.97 for Diamysis bahirensis; 7.48 for Siriella armata; 14.20 for Mysidopsis gibbosa; 4.49 for Euphausia crystallorophias; 1.66 for Euphausia superba; 2.74 for Streetsia challengeri; 13.26 for Meganycthiphanes norvegica. The species moreover showed a linear increase in enzyme activity in relation to the increase in sample concentration. The key result of this study concerns the different AChE activity basal values of the crustaceans' different species.     

外源凝集素──水产动物御敌的有力兵器

外源凝集素是非免疫起源的热敏蛋白质或糖蛋白，由于其多价构型及对持定细胞多糖具结合亲和力，它们选择凝集某些细胞（包括脊椎动物血球及一些病原微生物）和沉淀某些复杂碳水化合物；其凝集活动常被单糖所抑制，有的却需某些二糖、三糖或多糖。外源凝集素分离自广泛的低等和较高等的生物。一些地区水产养殖业受挫，因素较多，但对发病机理认识之缺乏和调动养殖对象本身防病积极性之不足，是其重要原因。外源凝集素可在诸如凝集外来细胞，调理作用等的防御活动中扮演识别因子，协助一些生理活性物发挥作用，参与吞噬、胞囊、凝固、止血及创伤修复等作用。在生物学、细胞学、生物化学、医学和食品科技上有广泛用途。迄今外源凝集素的许多性能并未全清，在自然界中的精细生理作用仍是个谜。本文论述外源凝集素的定义、性能及用途，以提请有关人士重视。     

Screening of Lectins in Crab and Shrimp from Fujian Coast of China

Twelve species of crustacean from Fujian coast were examined for lectins with different animal erythrocytes. Serum extracts fromall of 12 species showed agglutinating activity against at least two types of the erythrocytes used, which revealed the existence of lectins in these species. There were five species ( Penaeus japonicus, Lophosquilla costata, Charybdis feriatus, Portunus pelagicus, Scylla serrata ) whose serums could agglutinate all the erythrocytes tested. The lowest serum protein concentration required to produce erythrocytes agglutination varied remarkably, ranging from 0.7 μg/mL to 8 080 μg/mL. The strongest activity was shown in the agglutination of rabbit erythrocyte by serum of Penaeus vanaminas. Inhibition assays performed with seven mono- and bisaccharides showed that agglutination of quail erythrocytes by serums of three species (Portunus pelagicus, Scylla serrata and Sesarma sp. ) were not inhibited by any sugars, while others were inhibited by at least three types of sugars. The assay of temperature influence on agglutinating activity showed that only Penaeusjaponicus retained activity when the serum was heated to 90℃, and other serums lost their activity at 40 ℃, 50 ℃, 60 ℃, 70 ℃, 80 ℃ for 10 minutes, respectively.     

舟山沿岸渔场甲壳类群落结构特征研究

根据2015年11月和2016年5月在舟山沿岸渔场开展渔业资源调查所获得的甲壳类资料,应用相对重要性指数、生物多样性指数、多元统计分析等方法,对甲壳类的种类组成、优势种、生物多样性、相似性群落结构特征及其与环境之间的关系等进行了研究。结果表明,该项调查在舟山沿岸渔场共捕获并鉴定出甲壳类42种,其中,蟹类20种,隶属于11科5属;虾类21种,隶属于8科15属;虾蛄类1种,隶属于1科1属。秋季的甲壳类物种数高于春季,且秋季优势种有三疣梭子蟹(Portunus trituberculatus)、安氏白虾(Exopalaemon annandalei)以及口虾蛄(Oratosquilla oratoria),而春季则没有明显的优势种出现。生物多样性指数也表现为秋季明显高于春季,且随水深而变化的趋势明显。根据聚类(CLUSTER)分析与非度量多维标度排序(MDS)分析,可将甲壳类划分为4个群落,利用相似性(SIMPER)分析显示群落间相异程度高于相似程度,且秋季的群落相似性高于春季。     

Vertical distribution and seasonality of peracarid crustaceans associated with intertidal macroalgae

Spatial patterns and seasonal fluctuations of intertidal peracarids from Tarifa Island, Strait of Gibraltar, were studied over a two-year period (December 2005–December 2007). A total of 25,749 individuals were collected, comprising 46 species. Amphipods were best represented in the total number of species (32) and individuals (89% of numerical abundance) followed by isopods (12 species and 11% abundance) and tanaids (2 species and 1%). The highest number of species was registered in intermediate levels (1–1.5 m) dominated by Corallina elongata, although the highest abundances of peracarids were associated to seaweeds of lower levels (0–1 m) such as Gelidium corneum, Osmundea pinnatifida, Valonia utricularis and a turf of Caulacanthus ustulatus. The most abundant peracarids, Hyale stebbingi, H. schmidti, H. perieri, Stenothoe monoculoides, Caprella penantis, C. grandimana, Dynamene edwardsii and Ischyromene lacazei, were present throughout the whole year during 2006 and 2007. The highest peracarid densities were measured in April–August coinciding with the highest development of seaweeds, just before the maximum values of water temperature measured at the end of summer. Multivariate analyses confirmed a clear zonation of algae and associated peracarids in a vertical gradient, which was maintained stable during the two-year study. Several physical and biological factors may regulate such patterns of peracarid abundance and future experimental studies are necessary to explore the importance of factors such as competition, predation or weather conditions.     

Intersexuality in crustaceans: genetic, individual and population level effects

Scientists investigating toxicants such as endocrine disrupting chemicals (EDCs) at the cellular at the sub-cellular level are often faced with criticisms as to how these effects can be extrapolated to the level of individuals and their populations. This report aims to provide an overview of the studies undertaken on crustacean model, Echinogammarus marinus LEACH (AMPHIPODA), and intersex phenotypes, at the individual and population levels, and provide additional emergent data at the genomic level. These, normal and intersex, males and females have been investigated by cross-hybridisation microarray analysis and specific sexually dimorphic genes and corresponding properties identified between each sexual phenotype. The morphology, physiology and histology of these intersexes have been investigated in detail and a number of reproductive costs have been identified including reduced fecundity and fertility. These costs have been incorporated into a population model and simulated over a ten-year period to ascertain how different levels of intersexuality affect the stability of populations. Based on the information gained through study of intersex models (with known endocrine dysfunction) together with the substantial quantity of historical data relating to effects of chemicals on amphipod fecundity, growth and mortality, the development of appropriate biomarkers is nearer to being assessed from the level of genes to that of the population.     

Effects of rapid changes in temperature on two estuarine crustaceans

Weight specific oxygen consumption (Q_O2) patterns of the amphipod, Gammarus sp. (acclimated to 5°, 15° and 25°C) and of juvenile blue crabs, Callinectes sapidus (15° and 25°C) were used to evaluate the potential effect of exposure to rapid temperature changes simulating once-through power plant pumped entrainment. Amphipods at all acclimation temperatures and blue crabs at 15°C responded to the temperature changes by increasing Q_O2 above pre-exposure levels after the thermal increase and then returning to pre-exposure levels. The response was judged to be a normal physiological compensation response, not a thermal stress response, as suggested by some investigators. Significant differences were found among seasonal Q_O2, patterns in both species; Q_O2, increased with increasing acclimation temperature. However, no seasonal stress effects were found as a result of exposure to the temperature changes. This implies that the effects of ΔT's up to 10°C from power plants of this design should have no significant impact on these organisms.