蚌科钩介幼虫的比较形态学研究Ⅱ.六个种幼虫的形态

研究了真柱矛蚌、剑状矛蚌,洞穴丽蚌、角月丽蚌、三解帆蚌、褶纹完蚌等六种蚌的育作囊的类型和钩介幼虫的形态,应用光镜及扫描电僮对钩介幼虫的形态结构进行了观察和比较。结果表明 柱矛蚌、剑状矛蚌、三角帆蚌、褶纹冠的育儿囊为外鳃类同生型,洞穴丽蚌、角月丽蚌的育儿囊为外鳃类四生型、钩介幼虫可为二类：真柱矛蚌、剑状矛蚌、褶 纹冠蚌为有钩型,三角帆蚌、油穴丽蚌、角月丽蚌为无钩型。一些细微结构在不同种之间也存在着差     

背角无齿蚌生殖细胞及钩介幼虫的扫描电镜观察

本文报告背角无齿蚌的精子、卵子、钩介幼虫的扫描电镜观察。精子头部呈椭圆形,由顶体帽、顶体后区、核区和颈部组成,尾细长呈线状,卵子圆形,有许多卵闰,在生殖腺中有各种不同发育程度的卵细胞,钩介幼虫在育儿囊（外鳃）中发育,有一系列变态过程,表明卵子是分期分批排出,钩介幼虫也是分批发育和成熟的。     

珠蚌科六种蚌的钩介幼虫形态比较研究

本文观察了背角无齿蚌、沼纹冠蚌、剑状矛蚌、圆顶珠蚌、刻裂丽蚌和洞穴丽蚌等６种蚌的育儿囊类型;用光镜和扫描电镜观察和研究了幼虫的形态特征。结果表明,前４种蚌的育儿囊属外鳃类的同生型,后２种的育儿囊属外鳃类的四生型;６种幼虫均为钩介幼虫,其中前４种为有钩型,后２种为无钩型;６种幼虫的大小、形态有别,并证明种间幼虫的壳钧和壳饰的亚显微形态显然有异。本文还就６种蚌在Ｓｉｍｐｓｏｎ分类系统中的地位与按它们的育儿囊和钩介幼虫类型得到的归类进行比较。结果表明,Ｓｉｍｐｓｏｎ对６种蚌中３种的分类与归类不妥。本文为研究我国淡水贝类的分类提供一条新的途径,并为建立珠蚌类的自然分类系统积累资料。     

背角无齿蚌心肌纤维的超微结构观察

本文研究了背角无齿蚌心肌纤维的超微结构,在电子显微镜下观察了心脏各部结构固定的超薄切片,分析和讨论了河蚌心肌纤维的粗丝与细丝的排列状况和徽细结构,测最了粗丝和细丝的直径,并对线粒体,脂褐素等细胞器的形态结构,分布等进行了描述,对心肌纤维的连接方式进行了观察,并与脊椎动物心肌纤维的超微结构进行了相应的比较。     

蚌科钩介幼虫比较形态学研究 I.四个种幼虫的形态

本文报道圆顶珠蚌,鱼尾楔蚌,中国尖嵴蚌,卵形脊嵴蚌育儿囊的特点和钩介幼虫的形态,应用光镜和扫描电镜对四种蚌的钩介幼虫形态进行了观察和比较,结果表明,四种蚌的育儿囊均为外鳃类的同生型,钩介幼虫为有钩型幼虫的大小,形状,壳表面,壳钩,棘刺,幼虫丝,感觉毛等在不同种之间存在着差异,文中对这些特征在分类上的意义进行了讨论。     

背角无齿蚌珍珠囊形成过程的组织学和酶组织化学研究

本文采用Ｈ．Ｅ染色法和酶组织化学方法,对背角无齿蚌珍珠囊形成过程的组织学和酶组织化学的变化情况进行了研究,证实了“初生珍珠囊”的形成和溶解及“次生珍珠囊”的形成,并推没“次生珍珠囊”表皮细胞是由育珠蚌结缔组织转化而来的;观察了育珠手术后九种酶在珍珠囊形成的各个阶段和在珍珠囊和育珠蚌不同部位的变化情况,说明了珍珠囊珙成过程是与复杂的能量代谢,物质代谢及物质转运等有关的生理生化过程。     

圆背角无齿蚌血细胞吞噬作用的研究

初步研究了蚌血细胞离体条件下的吞噬作用以及血清因子对其的影响。发现蚌血细胞在无血清的条件下能独立完成对大肠杆菌的识别、吞噬。蚌血清对大肠杆菌有调理作用,能促进蚌血细胞对其的吞噬。介蚌血细胞不能识别、吸附和吞噬鸡红细胞,显示出蚌免疫防御能力的局限性。还发现ＥＤＴＡ能有效地抑制蚌血细胞凝集,其凝集作用可能与Ｃａ＾２＋等阳离子有关。     

背角无齿蚌珍珠囊形成过程中钙代谢的初步研究

本文采用同位素活体标记、人工育珠、普通石蜡切片和放射自显影的方法,对一种淡水育珠河蚌──背角无齿蚌珍珠囊形成过程中的钙代谢途径进行了研究,结果表明,由植入小片带入的钙在珍珠囊形成的过程中,主要代谢途径是：（１）随小片细胞脱落而进入游走细胞;（２）从小片进入初生珍珠囊,初生珍珠囊脱落后进入游走细胞;（３）从小片进入育珠蚌结缔组织,其中一部分再进入育珠蚌表皮,随粘液和壳质分泌;另一部分则进入次生珍珠囊表皮,分泌成为珍珠质的组成部分。实验结果说明了小片中的钙要参与育珠蚌组织的钙代谢,小片的质量对珍珠形成有重要的作用。     

蚌科钩介幼虫比较形态学研究──Ⅰ.四个种幼虫的形态

本文报道圆顶珠蚌、鱼尾楔蚌、中国尖嵴蚌、卵形尖嵴蚌育儿囊的特点和钩介幼虫的形态。应用光镜和扫描电镜对四种蚌的钩介幼虫形态进行了观察和比较。结果表明,四种蚌的育儿囊均为外鳃类的同生型,钩介幼虫为有钩型,幼虫的大小、形状、壳表面、壳钩、棘刺、幼虫丝、感觉毛等在不同种之间存在着差异。文中对这些特征在分类上的意义进行了讨论。     

背角无齿蚌晶杆的扫描电镜观察

本文应用扫描电镜的方法,对背角无齿蚌的晶杆进行了研究。结果表明：晶杆外形似圆柱状,可分为二部分,即前端膨大的头部和其后渐细的杆状部。前者分左右两瓣,略弯曲,与杆状部形成一个锐角,表面呈“蜂窝状”,似一种膜性结构,其上吸附有大量的消化酶和粘液;后者两侧有凹槽,表面具许多凹陷小坑,多为圆形或卵圆形,大小不一,深浅不同,且排列不规则。未凹陷处也粗糙不平。晶杆的功能主要是搅拌和消化食物。同时,本文对晶杆结构与功能的关系也进行了讨论。     

Isolation and characterization of microsatellite loci in western North American Anodonta species

We have developed and characterized 13 microsatellite loci from a group of Anodonta species in western North America, and demonstrated their utility in populations representing two major clades in this genus. Allelic diversity and polymorphic information content were high for all loci, although these characteristics varied across populations. Deviations from Hardy-Weinberg genotypic ratios were not detected, although the estimated frequency of null alleles was high in one population for one locus. This is the first set of microsatellite loci to be developed for freshwater mussels in western North America, and will be useful for describing gene flow patterns among populations.     

慢性镉暴露对背角无齿蚌肝脏的氧化损伤效应

目的:探明氯化镉(CdCl2)暴露对背角无齿蚌肝脏中抗氧化酶活力及脂质过氧化的影响。方法:根据背角无齿蚌96 h镉离子(Cd²⁺)半致死剂量设置1个对照组和2个处理组(0.1和0.5 mg/L),分别检测镉暴露4周及镉清除4周期间背角无齿蚌肝脏中抗氧化酶[超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GPx)、过氧化氢酶(CAT)]的活力和脂质过氧化物丙二醛(MDA)的含量。结果:不同浓度Cd²⁺暴露对背角无齿蚌抗氧化酶活力及脂质过氧化产生不同程度的影响,低浓度Cd²⁺暴露的毒性效应较弱,高浓度Cd²⁺暴露可显著抑制肝脏SOD活力,诱导GPx活力升高,在暴露后期显著抑制CAT活力,MDA含量随着暴露时间的延长而显著升高。结论:慢性Cd²⁺暴露可影响背角无齿蚌肝脏抗氧化酶活力,引起脂质过氧化损伤,且作用机制与急性毒性不同。     

Calcium exchanges in Anodonta cygnea: barriers and driving gradients

Electrical potential differences between the haemolymph and the extrapallial fluid, and between the haemolymph and the mantle cavity fluid, and ionic concentrations of calcium in the haemolymph and in extrapallial fluid were measured in vivo in Anodonta cygnea. The electrochemical potential of ionic calcium in the haemolymph is clearly above the electrochemical potential of ionic calcium in the environment and is very nearly in equilibrium with that of the extrapallial fluid. Simultaneous measurements of carbon dioxide partial pressure and pH in the extrapallial fluid showed that in this compartment ionic calcium is clearly above saturation. It is proposed that calcium deposition is regulated through the secretion of the organic matrix and by controlling the pH and the carbon dioxide partial pressure of the extrapallial fluid. An estimation of the minimum positive balance of calcium required to sustain shell growth together with the electrophysiological characterization of the mantle cavity epithelium showed that this tissue is not the route of entry of calcium into the animal.Abbreviations BW body weight - DW dry weight - E_EPF-S chemical potential difference - EPF extrapallial fluid - G_tot total conductance - I_sc short-circuit current - K_sp solubility product - MCE mantle cavity epithelium - MCF mantle cavity fluid - OME outer mantle epithelium - PCO₂ partial pressure of carbon dioxide - PVC Poly(vinyl chloride) - S shell - SEM standard error of mean - V_ic intracellular electrical potential - V_oc open-circuit voltage     

Studies on chitin and calcification in the inner layers of the shell of Anodonta cygnea

Summary An orthorhombic structure -chitin, probably in the form of a chitin-protein complex, was identified in the matrix of the shell of Anodonta cygnea by X-ray diffraction. Aragonite crystals of pseudohexagonal symmetry were also found by a Lauegram on the nacreous layer of the shell. The orthorhombic structure of these two compounds together with the identical reticular spacing d₁₁₀ corroborate, in Anodonta cygnea, the indirect chitin-aragonite relationships already suggested for molluscan shells.Observations with SEM in the inner surface of the shell showed CaCO₃ crystals with irregular geometrical shapes in spring and summer and regular geometrical shapes in autumn and winter. The more elaborate aspect appearing in winter corresponds to an accurate hexagonal shape. This suggests that the observed variability may depend on the balance between calcium and hydrogen ions in the extrapallial fluid.Abbreviations OME outer mantle epithelium - SEM scanning electron microscopy     

Climate effects on inter‐annual variation in growth of the freshwater mussel (Anodonta beringiana) in an Alaskan lake

1. Warming trends are evident in many parts of the globe but are especially marked at higher latitudes, with complex effects on the biota that include direct effects on growth potential and indirect effects through food webs. 2. Air temperatures have been increasing over the past 50 years in southwestern Alaska, affecting the growth and population dynamics of many organisms, including a variety of aquatic species such as the freshwater mussel Anodonta beringiana. 3. We collected freshwater mussels from Iliamna Lake, in the Bristol Bay region of Alaska, and measured their shells to examine climatic effects on growth patterns. 4. Linear mixed effects models and ordinary least square linear regressions revealed strong positive correlations between local air temperatures (especially in May, October and the summer months) and inter‐annual variation in mussel growth. Slower mussel growth was also significantly correlated with later date of ice break‐up, which was linked to air temperatures in late spring.     

常用鱼药漂白粉和氯杀宁对背角无齿蚌的毒性影响

试验以洱海流域的背角无齿蚌为研究对象,确定常用鱼药:漂白粉、氯杀宁对湖泊大型底柄动物背角无齿蚌的毒性影响.试验得出漂白粉作用下,背角无齿蚌24 h、48 h、72 h、96 h、120 h、144 h、168 h的半致死率;氯杀宁作用下,背角无齿蚌24 h、48 h、72 h、96 h的半致死率;漂白粉有效氯安全浓度95.25～108.86 mg/L;氯杀宁有效氯安全浓度3.32～3.55 mg/L.通过显微镜观察,漂白粉和氯杀宁的主要作用部位为背角无齿蚌的呼吸系统,在其鳃上可见明显病变.     

Genetic structuring in the freshwater mussel Anodonta corresponds with major hydrologic basins in the western United States

Freshwater mussels (unionids) are increasingly recognized as important providers of ecosystem services, yet are among the most endangered fauna in the world. Because unionids are generally sessile and require specific fish hosts for development and dispersal, they are particularly vulnerable to habitat degradation. Surprisingly, little is known about the distribution of genetic diversity in freshwater mussels and this gap has a negative impact on taxonomy, monitoring, conservation and ecological research in these species. Here, we focus on western North American Anodonta, one of only three genera known to exist in this broad landscape and which contains three highly divergent lineages. We describe phylogeographical subdivision in the most widespread and diverse of these lineages, which includes Anodonta californiensis and Anodonta nuttalliana and occurs from Canada to Mexico. Using mitochondrial and nuclear data, we found that genetic structuring within this clade is inconsistent with morphologically based species designations, but instead follows patterns of vicariance among major hydrogeologic basins. Furthermore, there was a strong tendency for population diversity within drainage systems to increase downstream, implying greater habitat or host fish availability in this direction. Microsatellite results indicated that sampling locations were all genetically distinct, even at short distances. Many of our sample populations showed evidence of a recent demographic bottleneck, although this effect seemed to be very local and not drainage or basin‐specific. This study provides a foundation for the establishment of appropriate management units and future research on adaptive differentiation and host fish relationships.     

Correlation between the morpho-cytohistochemistry of the outer mantle epithelium of Anodonta cygnea with seasonal variations and following pollutant exposure

Seasonal and experimental conditions induce morphological and cytochemical variations in the outer mantle epithelium (OME) of the freshwater bivalve Anodonta cygnea, probably influencing the shell calcification mechanism. In this study, OME samples were taken from untreated animals in autumn, winter, spring and summer as well as from animals exposed to divalent metals (cadmium, chromium, lead, copper and zinc) and pesticides (setoxidim and dimethoate) and observed by light microscopy. The present results showed that OME cells have larger cell volumes and increased amounts of secreted macromolecules during spring and summer than in autumn and winter. This correlates with higher shell calcification rates in spring and summer and lower shell calcification rates in autumn and winter. The experiments showed that incubation with pollutants for 8 months dramatically reduced the cellular volume so that the density of cytoplasmic material appeared higher that in the control samples. The pronounced changes in OME cells suggest a significant decrease in secretory activity following exposure to toxic agents and this has implications for the shell calcification process.     

在旱化土壤条件下来自不同生境的20种植物幼苗根系的形态反应的比较(英文)

在浇水和未浇水的塑料管中栽培了 2 0个植物种 ,测量了其幼苗的根深、根重和茎重。这些种的原始生境含水状况差异较大 ,是从沼泽到沙漠的系列。植物种原始生境的水分状况用Ellenberg水分序数定量。幼苗首先在湿沙中生长 2 1d ,然后进入为期也是 2 1d的处理阶段 (浇水和不浇水 )。浇水植株的根深与Ellenberg水分序数无关。在旱化的沙层中 ,源于干旱生境的植物的根深趋向于增加 ,来自湿润生境的则减少。根深塑性 (即未浇水的根深 /浇水的根深 )与Ellenberg水分序数显著相关 (R2 =0 .5 6 ) ,茎 /根比值塑性也与Ellenberg水分序数相关 ,但不如根深塑性的关系明显。根深塑性表现最为明显的植物种具有在未浇水沙层中维持茎生长的最大能力。有迹象表明 ,在浇水处理时 ,来自很干旱生境的植物生长减弱。研究结果表明 :幼苗利用深层水分的能力是植物对干旱生境的主要适应。     

Seasonal variations of pH, pCO2, pO2, HCO3- and Ca2+ in the haemolymph: implications on the calcification physiology in Anodonta cygnea

A study about the relationship between the physical–chemical parameters and the calcium carbonate balance between the haemolymph fluid and mantle calcareous structures was carried out in Anodonta cygnea. An intense peak of HCO₃ ⁻ and a highest pH in December–January months may be understood as a preparation period for creating alkaline conditions. An intense pH decrease from January to February in parallel with the HCO₃ ⁻ reduction seems to indicate the beginning process of carbonate precipitation. On the other hand, the following calcium and HCO₃ ⁻ increases in February–May associated with a continuous and gradual pH fall profile may infer two combined aspects: calcium and HCO₃ ⁻ absorption from external environment and a simultaneous intense calcium carbonate deposition in the haemolymph. So, the pCO₂ peak in this period reflects a subsequent result on equilibrium balance between HCO₃ ⁻ absorption and deposition. The only significant pO₂ increase in the next period, from February to June, is related with an energetic increase to support the metabolic activity favouring the posterior intense pCO₂ peaks. The extended time of CO₂ production in the haemolymph from May to November should induce an increased metabolic acidosis with subsequent intense formation of both HCO₃ ⁻ and Ca²⁺ ions in the same period. This seems to result from CaCO₃ deposits dissolution in the haemolymph, the most direct calcareous source. Additionally, the later increase of metabolic succinic acid during autumn may greatly potentiate this acidosis increasing the dissolution process. Consequently, the pH profile present two simultaneous alkaline peaks in July and October, probably due to a strong HCO₃ ⁻ release from the CaCO₃ dissolution. So, the present seasonal results indicate that in the freshwater bivalve A. cygnea, the low metabolism with higher pH from the early winter is the main cause which may favour a calcareous precipitation, while the high metabolism with lower pH from the early summer may function as an inductor of calcareous dissolution in the haemolymph.