溴氰菊酯对菲律宾蛤仔体内酶活性和组织损伤的初步探索

采用不同质量浓度的溴氰菊酯(0.0070 mg·L~(-1)、0.014 mg·L~(-1)、0.020 mg·L~(-1)、0.027 mg·L~(-1))对菲律宾蛤仔进行20 d半静置染毒,测定不同时间淋巴液中乙酰胆碱酯酶(ACh E)和钠离子-钾离子-三磷酸腺苷酶(Na~+-K~+-ATPase)活性、鳃和肝脏中谷胱甘肽转硫酶(GST)活性的变化,并观察染毒20 d后鳃丝组织和消化盲囊组织的损伤情况。酶活性分析结果显示,与对照组相比,低浓度组(0.0070 mg·L~(-1))试验期间酶活性均无显著差异(P0.05);中浓度组(0.014 mg·L~(-1)、0.020 mg·L~(-1))淋巴液中ACh E和Na~+-K~+-ATPase均呈先激活后抑制的变化规律(P0.05),鳃和肝脏中GST活性均呈上升趋势(P0.05);高浓度组(0.027mg·L~(-1))淋巴液中ACh E和Na~+-K~+-ATPase、肝脏中GST活性在试验期间持续下降(P0.01),而鳃中GST活性呈先抑制后升高的趋势(P0.05)。研究表明,低中浓度的溴氰菊酯对菲律宾蛤仔体内的酶活性表现为先诱导后抑制,具有明显的时间、剂量效应;高浓度的溴氰菊酯对菲律宾蛤仔体内酶活持续抑制,且染毒浓度越高,组织细胞变异越显著,表现为鳃丝上皮细胞纤毛层萎缩、纤毛脱落,消化盲囊上皮细胞膨胀,出现包涵体样结构。     

Effects of environmental hypercapnia on hemato-immunological parameters,carbonic anhydrase,and Na+, K+-ATPase enzyme activities in rainbow trout (Oncorhynchus mykiss) tissues

In this study, the effects of environmental hypercapnia on hemato-immunological parameters and the activities of respiratory enzymes such as carbonic anhydrase (CA) and Na⁺, K⁺-ATPase were investigated in rainbow trout (Oncorhynchus mykiss) tissues (gill, liver and kidney). Batches of 12 fish were exposed to 4.5 mg L^?1 (control) and 14 mg L^?1 CO₂. No mortalities occurred during the 14 days of the experimental period. Red blood cell (RBC), hemoglobin (Hb), and hematocrit (Ht) levels, and innate immune parameters such as nitro blue tetrazolium (NBT), lysozyme, and myeloperoxidase activities, and the melano-macrophage frequency were negatively affected by elevated CO₂ levels. Patterns of change in CA activity differed among the gill, liver, and kidney. Compared with the activities of CA in the control group, the CA enzyme was significantly stimulated at day 7 in the gill tissue, whereas it was stimulated at day 14 of the experiment in the liver tissue of fish exposed to 14 mg L^?1 CO₂ (P < 0.05). In contrast to the pattern of CA enzyme activities, the Na⁺, K⁺-ATPase enzymes were stimulated significantly in the liver after day 7 but inhibited in the kidney and gill (P < 0.05). These results suggest that a subchronic exposure to hypercapnia of rainbow trout tissues may lead to adaptive changes in the respiratory enzymes and negatively affects hemato-immunological parameters.     

Tissue-specific stress and hepatic DNA damage in Pelteobagrus fulvidraco caused by low concentrations of cadmium

Physiological stress and DNA damage in Pelteobagrus fulvidraco induced by continuous exposure to cadmium at concentrations of 170 and 1700 µg/L for up to 28 days was evaluated. The activities of acetylcholinesterase and monoamine oxidase in brain tissue, Na⁺-K⁺-ATPase and glutathione in gill tissue, and superoxide dismutase and catalase in liver tissue were measured. In studying random amplified polymorphic DNA to evaluate cadmium-induced hepatic genotoxicity, both the appearance of new bands and the disappearance of existing bands were observed, as well as increased levels of monoamine oxidase and Na⁺-K⁺-ATPase and decreased activities of antioxidant enzymes. The results suggest that continuous exposure to cadmium at the studied levels can induce biochemical and physiological changes and DNA damage in P. fulvidraco.     

Interaction of alcohol and kola nut on brain sodium pump activity in Wistar rats

The effect of interaction of alcohol and kola nut on sodium pump activity was studied in Wistar rats. Thirty Wistar rats were divided into six groups of five rats per group. Control received a placebo (4 mL of distilled water). Groups 2–6 were treated for a period of 21 days with 10% (v/v) alcohol, 50 mg caffeine/kg, 50 mg kola nut/kg, or a combination of 10% (v/v) alcohol + 50 mg kola nut/kg, or 10% (v/v) alcohol + 50 mg caffeine/kg, respectively. One day after the final exposure, brains were harvested and several biochemical parameters examined including activities of total ATPase, ouabain-insensitive ATPase, ouabain sensitive ATPase (Na⁺–K⁺-ATPase) and levels of nonenzymatic breakdown of ATP and inorganic phosphate (P_i) released. Results showed that the essential enzyme of the brain responsible for neuronal function, Na⁺–K⁺-ATPase, was inhibited by alcohol–kola nut co-administration relative to control, resulting in a decreased ATP production, ion transport and action potential, leading to loss of neuronal activities.     

Gas–liquid chromatography for fenvalerate residue analysis: alterations in the ionic concentration and associated adinosine triphosphatases in fish,Cirrhinus mrigala (hamilton)

In the present study, an attempt has been made to quantify the fenvalerate accumulated in different tissues (gill, muscle and liver) and observe changes involved in the levels of sodium, potassium and calcium ions and Na⁺–K⁺, Mg²⁺ and Ca²⁺ adenosine triphosphatase (ATPase) activities in the freshwater fish, Cirrhinus mrigala on short-term and long-term exposure to the median lethal and sublethal concentration of fenvalerate. Residue analysis using gas–liquid chromatography (GLC) technique revealed that fenvalerate accumulated in highest quantity in gill followed by liver and muscle under median lethal concentration (6?µg?L^?1). Whereas in sublethal concentration (0.6?µg?L^?1), muscle accumulated highest quantity followed by gill and liver, which might be due to the fact that fenvalerate is highly lyphophilic. The ion concentration and ATPase activity were found effected in fish exposed to lethal and sublethal concentrations of fenvalerate. Concentration of Na⁺, K⁺ and Ca²⁺ ions decreased in gill, muscle and liver on being exposed to median lethal concentration to a significant level. Whereas the changes were not highly pronounced at sub lethal level indicating low concentration of fenvalerate and its non-toxic effect at chronic exposure. Na⁺–K⁺, Mg²⁺ and Ca²⁺ ATPases activity were also found decreased in correspondence to the ionic change under median lethal and sub lethal concentrations in target tissues. This might have lead to behavioural changes and create wide-spread disturbance in the normal physiology, ultimately causing the death of the fish. The results suggest that in biomonitoring programmes, ions and associated ATPases can be a good diagnostic tool for fenvalerate toxicity.     

食物源nC_(60)损害斑马鱼脑、鳃、肾和肝胰腺正常机能

水体中稳定存在的富勒烯纳米晶体(nC_(60))可被浮游动物滤食,并通过食物链传递到更高营养级生物。为探究食物源nC_(60)的生物效应,本试验选取携带nC_(60)的大型溞喂养斑马鱼21 d,考察了食物源nC_(60)对斑马鱼脑、鳃、肾和肝胰腺4个器官中ROS、Na~+K~+-ATPase、Ca2+-ATPase、酸性磷酸酶(ACP)、碱性磷酸酶(AKP)、谷丙转氨酶(GPT)和谷草转氨酶(GOT)活性等指标,用以评价食物源nC_(60)对斑马鱼的机能影响。暴露于食物源nC_(60)下的结果表明:斑马鱼脑ROS随时间增加而增加,暴露21 d后增加了79.17%。鳃、肾Na~+K~+-ATPase活性随暴露时间增加而降低,暴露21 d后分别降低了47.09%和51.07%;鳃、肾Ca2+-ATPase活性随暴露时间增加而减少,暴露21 d后分别降低了28.28%和35.13%。鳃、肾、肝胰腺AKP活性随时间增加而增加,暴露21 d后分别增加45.97%、26.68%和83.01%;鳃、肾、肝胰腺ACP活性随时间增加而增加,暴露21 d后分别增加38.85%、84.12%和55.77%。肝胰腺GPT和GOT活性随时间增加而降低,暴露21 d后各降低了50.05%和76.50%。本研究不但阐述了食物源nC_(60)降低高一级水生动物(斑马鱼)脑、鳃、肾和肝胰腺的正常机能,而且为进一步研究食物源nC_(60)对水生生物的生态毒理提供了部分基础数据。     

Na+-K+-adenosine triphosphatase activities in gills of marine teleost fishes: Changes with depth,size and locomotory activity level

Activities of the primary enzyme responsible for monovalent ion regulation, Na⁺-K⁺-adenosine triphosphatase (Na⁺-K⁺-ATPase), were measured in gills of marine teleost fishes with different depths of occurrence (0 to 4800 m), body weights (a range of five orders of magnitude), and locomotory capacities. Specimens were collected off the coasts of California and Oregon in 1983–1989, and at the Galápagos Spreading Center and 13°N East Pacific Rise hydrothermal vent sites in 1987 and 1988, respectively. Except for two hydrothermal vent fishes, deep-sea species had much lower Na⁺-K⁺-ATPase activities g^–1 gill filament than shallow-living species, indicating that osmoregulatory costs, like total metabolic rate, are greatly reduced in most deep-living fishes. Within a species, the total branchial Na⁺-K⁺-ATPase activity per individual was dependent on size; the average allometric scaling exponent was 0.83. Using published values for oxygen consumption rates, and the total branchial Na⁺-K⁺-ATPase activities as an index of osmoregulatory costs, we estimated the maximal cost (as percent of ATP turnover) for osmoregulation in ten teleosts. Osmoregulatory costs averaged about 10% of total ATP turnover among these species, and maximal costs were no greater than about 20%. The percent costs of osmoregulation did not differ between shallow- and deep-living fishes. The reduced total ATP expenditure for osmoregulation in deep-living fishes is proposed to result from the sluggish locomotory habits of these fishes, not from selection for reduced osmotic coastper se. Thus, the reduced swimming abilities of these fishes lead to lower rates of water flow over the gills and less blood flow through the gills due to reduced demands for oxygen. Consequently, passive flux of water and ions through the gills is much lower than in more active fishes, and osmotic costs are thereby minimized. The relatively high activities of Na⁺-K⁺-ATPase in gills of the two hydrothermal vent fishes suggest that these fishes may be more active and have higher metabolic rates than other deep-sea fishes.     

Ecotoxicity of silver nanoparticles on earthworm Eisenia fetida: responses of the antioxidant system,acid phosphatase and ATPase

Ecotoxicity of nanoparticles has received growing attention in recent years. This study investigated the influence of silver nanoparticles (Ag-NP) on earthworm Eisenia fetida. The experiment was performed with five test groups: control (without Ag-NP), 10?nm Ag-NP groups (20, 100 or 500?mg?kg^?1) and positive control (787?mg?kg^?1 AgNO₃). After 14-day acute exposure, activities of various enzymes, including glutathione S-transferase (GST), glutathione reductase (GR), acid phosphatase (AP), and Na⁺, K⁺-ATPase were determined. Effects of Ag-NP with different sizes (10 and 80?nm) were also tested. Data showed that the activity of GR was significantly lower at 500?mg?kg^?1. The activities of AP and Na⁺, K⁺-ATPase were inhibited following the increase of Ag-NP concentration. When treated with Ag-NP with different sizes, activities of AP and Na⁺, K⁺-ATPase of the 10?nm group were significantly lower than the control group, but those of the 80?nm group were similar to the control group. Data indicate that Ag-NP may be harmful to the earthworm E. fetida at 500?mg?kg^?1, and the toxicity of Ag-NP with 10?nm size is greater than 80?nm. In addition, AP and Na⁺, K⁺-ATPase are sensitive biomakers to the effects of Ag-NP.     

Effects of ammonia on survival and osmoregulation of various development stages of the shrimp Penaeus japonicus

In Penaeus japonicus, the tolerance to ammonia increased with the development from nauplius to late juvenile. The 48-h LC₅₀ of ammonia in nauplii (III–V), 96-h LC₅₀ in zoeae (I–III), mysis (I–III), post-larvae (PL1) and late juveniles (10.4±1.1 g) were respectively 5.0, 6.1 to 8.1, 9.4 to 10.9, 15.5 and 52.7 mg Nl^-1 (0.5, 0.6 to 0.7, 0.9, 1.3 and 3.1 mg NH₃–Nl^-1). In a chronic experiment (20 d), the LC₅₀ in post-larvae (PL1) was 19.1 (1.4) at 96 h and 16.2 mg Nl^-1 (1.3 mg NH₃–Nl^-1) at 480 h. Osmoregulatory capacity (OC) was calculated as the osmotic gradient between the hemolymph and the external medium at given salinities. The effects of ammonia on OC, Na⁺ and Cl^- regulation and gill Na⁺–K⁺ ATPase activity in late juveniles were examined in fullstrength seawater, SW (1050 mosm kg^-1, 36 S) and in dilute SW (450 mosm kg^-1, 15%.), after 48 or 96 h exposure to various concentrations of ammonia. Ambient ammonia disrupted both hypo- and hyper-osmoregulation; decreased OC resulted from impaired Na⁺ and Cl^- regulation. Gill Na⁺–K⁺ ATPase activity increased in SW and was not affected in dilute SW. The decrease of OC was ammonia-dose-dependent. The threshold ammonia concentrations affecting hypo-OC and hyper-OC were, respectively, 16 (1.3) and 32 mg Nl^-1 (2.3 NH₃–Nl^-1) for a 48 h exposure; these concentrations were lower than the 48-h LC₅₀ value, 65.3 mg Nl^-1 (3.5 NH₃–Nl^-1). The time course of exposure to sublethal ammonia (48 mg Nl^-1) demonstrated that the effect on osmoregulation was time-dependent. This effect was also temporary, and the exposed shrimps recovered control OC values after removal of excessive ambient ammonia. The possibility of using OC as an indicator of physiological condition in osmoregulating crustaceans and the acting mode of ammonia on osmotic and ionic regulation are discussed.     

Inhibition of Na+/K+-ATPase and of active ion-transport functions in the gills of the shore crab Carcinus maenas induced by cadmium

Inhibition of Na⁺/K⁺-ATPase from gill plasma membranes of the shore crab Carcinus maenas by cadmium was investigated and compared with inhibitory effects by known antagonists (ouabain and Ca²⁺). For comparative considerations the Cd²⁺-inhibition of the enzyme from dog kidney was also tested. Na⁺/K⁺-ATPase from dog kidney and from crab gill differed greatly in sensitivity against ouabain. The inhibition constant K _i of the dog enzyme amounted to 9.1 × 10⁻⁷ mol l⁻¹, i.e. more than 300-fold smaller than the K _i of 2.9 × 10⁻⁴ mol l⁻¹ determined for the crab enzyme. Ca²⁺ inhibited the activity of Na⁺/K⁺-ATPase from crab gill plasma membranes with a K _i of 4.3 × 10⁻⁴ mol l⁻¹. The Na⁺/K⁺-ATPase from crab gill was inhibited by Cd²⁺ with a K _i of 9.1 × 10⁻⁵ mol l⁻¹. Cd²⁺ inhibited the Na⁺/K⁺-ATPase from dog kidney with a K _i (6.4 × 10⁻⁵ mol l⁻¹) comparable to that observed in the crab gill enzyme. Under experimental conditions Cd²⁺-inhibition of Na⁺/K⁺-ATPase was irreversible. Repeated washing, centrifugation and homogenization of the plasma membranes (four times) with Cd²⁺-free buffer did not restore any activity lost in the presence of 1 × 10⁻³ mol l⁻¹ Cd²⁺. Since ouabain-insensitive (nonspecific) ATPases in the plasma membrane fraction of crab gills were inhibited by Cd²⁺ in the same way as Na⁺/K⁺-ATPase, the heavy metal is considered as an unspecific ATPase inhibitor. Comparing these results with literature data on Cd²⁺-binding to electrophoretically separated proteins suggests that Na⁺/K⁺-ATPase is a Cd²⁺-binding enzyme. The results obtained on Na⁺/K⁺-ATPase were reflected by Cd²⁺-inhibition of the branchial ion-transport functions depending on this enzyme. The transepithelial short-circuit current of isolated gill half lamellae, a direct measure of area-specific active ion uptake, and the transepithelial potential difference of isolated, perfused whole gills, also indicative of active ion uptake, were inhibited by the heavy metal in a time- and dose-dependent mode. Remarkably these inhibitions were also irreversible. These findings are ecologically and biomedically significant: even when the actual environmental or tissue concentrations measured are low, biological microstructures such as Na⁺/K⁺-ATPase may accumulate the heavy metal by tight binding over prolonged periods until the first inhibitory effects occur. Received: 25 June 1997 / Accepted: 25 August 1997     

A comparison of transport-related gill enzyme activities and tissue-specific free amino acid concentrations of Baltic Sea (brackish water) and freshwater threespine sticklebacks, Gasterosteus aculeatus, after salinity and temperature acclimation

The osmoregulatory abilities of one freshwater and two brackish water (Baltic Sea) populations of the euryhaline teleost fish Gasterosteus aculeatus were studied with respect to evolutionary physiology. Plasma osmolality, activities of Na⁺K⁺-ATPase, citrate synthase, creatine kinase in the gill and free amino acids in liver, axial muscle and pectoral fin muscle were measured. After transfer from 10 to 35 ppt at 15 °C, time-course changes of plasma osmolality and gill Na⁺K⁺-ATPase showed no significant fundamental differences between the freshwater and one of the Baltic Sea populations. In a multi-factorial experiment, each population was exposed to four different abiotic regimes. Both brackish water populations had high mortality in freshwater at 4 °C, which is discussed as a failure of osmotic regulation (reduced taurine concentrations). Freshwater specimens had higher levels of glycine in the axial and pectoral fin muscles compared to the brackish water populations. This is interpreted as a genetically based effect. In brackish (20 ppt) water of 15 °C, the freshwater population had high activities of Na⁺K⁺-ATPase, but low activities of creatine kinase, whereas both brackish water populations behaved in the opposite way. A fundamental difference between the freshwater and brackish water populations on the level of the osmoregulatory machinery was not observed. Received: 10 December 1998 / Accepted: 22 September 1999     

In vitro and in vivo inhibition of Ca2+-Mg2+-ATPase activity by cadmium in post larvae of Penaeus monodon

Ca²⁺-Mg²⁺-ATPase is a membrane-bound enzyme and is responsible for regulating cytosolic free calcium. In vitro and in vivo effects of cadmium were studied on Ca²⁺-Mg²⁺-ATPase activity in plasma membrane/mitochondrial fraction of Penaeus monodon post larvae. In vitro studies revealed a concentration-dependent decrease in enzyme activity with an IC₅₀ value of 11.02?µM. In vivo experiments were conducted by exposing the post larvae to 1/10th (0.12?ppm) and 1/5th (0.24?ppm) of LC₅₀ values of cadmium for 30 days. Both ATPase activity and metal accumulation were estimated in post larvae exposed to 0.12 and 0.24?ppm of cadmium at different intervals of 24?h, 48?h, 96?h, 10 days and 30 days. ATPase activity showed a gradual decrease in post larvae on exposure to both the sub-lethal concentrations with respect to their controls and the decrease was significant (p?相似文献   

Acute toxicity of ammonia to a freshwater teleost,Labeo bata larvae

Ammonia toxicity tests were performed with Labeo bata (bata) larvae of three different size groups. One hundred percent survival of larvae (500.0?±?4.0?mg) was recorded when exposed to ammonia concentrations of 1.0–13.56?mg?L^?1 at 96?h of exposure. Bata larvae exposed to ammonia concentrations of 15.8–25?mg?L^?1 showed 10–74% mortalities. The 96?h LC₅₀ value for 200 (±5), 250 (±2) and 500 (±4) mg bata larvae were 11.5, 16.8 and 22.5?mg?L^?1 un-ionised ammonia concentrations, respectively. When fish were exposed to different doses of ammonia, behavioural changes immediately occurred even at the lowest dose. At first, the fish became hyperexcitable, the skin darkened and they showed an increased ventilation frequency, fish behaviour became normal, 24?h after exposure. A 96?h LC₅₀ value of un-ionised ammonia showed direct relationship with the increasing size of bata larvae.     

Effects of three different nanoparticles on bioaccumulation,oxidative stress,osmoregulatory, and immune responses of Carcinus aestuarii

Abstract

In this study, the toxicity of CuO (40?nm), α-Al₂O₃ (40?nm), and α-Fe₂O₃ (20–40?nm) nanoparticles was comparatively investigated on Carcinus aestuarii. Crabs were semi-statically exposed to 1?mg/L of each for 14?days and their accumulation and distribution in tissue and hemolymph, potential oxidative stress mechanism, total hemocyte counts and types, and the osmoregulatory and ionoregulatory responses were determined. The tissue distribution of CuO nanoparticles was hepatopancreas?>?hemolymph?≥?gill?> muscle, for α-Fe₂O₃ gill?>?hepatopancreas?>?muscle?> hemolymph, and for α-Al₂O₃ gill?>?muscle?≥?hemolymph?> hepatopancreas. While α-Al₂O₃ and α-Fe₂O₃ NPs, induced lipid peroxidation and changes in antioxidant enzyme activity in the hepatopancreas tissue, the oxidative damage caused by the CuO nanoparticles was minimal. All three nanoparticles, copper in particular, elicit osmoregulatory and ionoregulatory toxicity at this concentration, due to the inhibition of Na⁺, K⁺-ATPase activity in the gill and depletion of hemolymph and carcass ion concentrations.     

Gill and intestinal Na+-K+ ATPase activity, and estimated maximal osmoregulatory costs, in three high-energy-demand teleosts: yellowfin tuna (Thunnus albacares), skipjack tuna (Katsuwonus pelamis), and dolphin fish (Coryphaena hippurus)

We hypothesize that the morpho-physiological adaptations that permit tunas to achieve maximum metabolic rates (MMR) that are more than double those of other active fishes should result in high water and ion flux rates across the gills and concomitant high osmoregulatory costs. The high standard metabolic rates (SMR) of tunas and dolphin fish may, therefore, be due to the elevated rates of energy expenditure for osmoregulation (i.e. teleosts capable of achieving exceptionally high MMR necessarily have SMR). Previous investigators have suggested a link between activity patterns and osmoregulatory costs based on Na⁺-K⁺ ATPase activity in the gills of active epipelagic and sluggish deep-sea fishes. Based on these observations, we conclude that high-energy-demand fishes (i.e. tunas and dolphin fish) should have exceptionally elevated gill and intestinal Na⁺-K⁺ ATPase activity reflecting their elevated rates of salt and water transfer. To test this idea and estimate osmoregulatory costs, we measured Na⁺-K⁺ ATPase activity (V _max) in homogenates of frozen samples taken from the gills and intestines of skipjack and yellowfin tunas, and the gills of dolphin fish. As a check of our procedures, we made similar measurements using tissues from hybrid red tilapia (Oreochromis mossambicus ×O. niloticus). Contrary to our supposition, we found no difference in Na⁺-K⁺ ATPase activity per unit mass of gill or intestine in these four species. We estimate the cost of osmoregulation to be at most 9% and 13% of the SMR in skipjack tuna and yellowfin tuna, respectively. Our results, therefore, do not support either of our original suppositions, and the cause(s) underlying the high SMR of tunas and dolphin fish remain unexplained. Received: 7 September 2000 / Accepted: 4 December 2000     

Effects to perfluorooctane sulfonate (PFOS) on the mollusk Unio ravoisieri under laboratory exposure

To understand acute toxicity and oxidative stress of perfluorinated compounds in the freshwater ecosystems, we exposed freshwater mussels (Unio ravoisieri) to perfluorooctane sulfonate (PFOS), over a range of concentrations from 10 to 100?mg/L, in a laboratory experiment. Lethal concentration (LC50) was of about 65.9?mg/L after 96?h of exposure. The oxidative stress was assessed in gill and digestive gland of the freshwater mussels after 7 days of exposure to different nominal PFOS concentrations (C1=?2?mg/L, C2?=?6?mg/L and C3=?10?mg/L). C1 and C2 increased significantly (p?<?.05) the superoxide dismutase activity in both tissues compared, while the highest C3 decreased the enzyme activity. This implements an unfavourable response that highlights the excess of reactive oxygen species produced after contamination. The Catalase activity was also increased by about 40.05% and 66.63%, respectively, in gill and digestive gland after exposure to C3. The Malondialdehyde (MDA) level was increased in both gill and digestive gland in a concentration-dependent pattern. In contrast, the contamination of U. ravoisieri by PFOS did not affect the acetylcholinesterase activity in both organs (p?>?.005). These results provided information on potential biomarkers that could be effectively applied for the monitoring of freshwater ecosystem using indicator species such as U. ravoisieri.     

Ontogenic change of gill chloride cells in leptocephalus and glass eel stages of the Japanese eel, <Emphasis Type="Italic">Anguilla japonica</Emphasis>

The development of gill chloride cells was examined in premetamorphic larvae (leptocephali) and juveniles (glass eels) of the Japanese eel, Anguilla japonica. Branchial chloride cells were detected by immunocytochemistry using an antiserum specific for Na⁺,K⁺-ATPase. The specificity and availability of the antiserum for the detection of Japanese eel chloride cells were confirmed by Western blot analysis. The chloride cells first appeared on the developing gill filaments in a mid larval stage of leptocephalus (32.2 mm). Both immunoreactivity and the number of chloride cells gradually increased as the fish grew to a late stage of leptocephalus over 54 mm. In glass eels just after metamorphosis, gill lamellae developed from the gill filaments, and a rich population of chloride cells was observed in the gill filaments. In glass eels collected at a coastal area, chloride cells were extensively distributed in the gill filaments. The chloride cell size decreased progressively in glass eels transferred from seawater (SW) to freshwater (FW), whereas there was no difference in cell number. In contrast, some Na⁺,K⁺-ATPase immunoreaction distinct from typical chloride cells was observed in the gill lamellae throughout FW-transferred fish, but disappeared in control fish maintained in SW for 14 days. These findings indicate that the gill and gill chloride cells developed slowly during the extremely long larval stage, followed by rapid differentiation during a short period of metamorphosis. The excellent euryhalinity of glass eels may be due to the presence of the filament chloride cells and lamellar Na⁺,K⁺-ATPase-immunoreaction, presumably being responsible for SW and FW adaptation, respectively.     

Sodium- and potassium-activated adenosine triphosphatase in the excretory organs of Sepia officinalis (Cephalopoda)

Sodium- and potassium-activated ATPase (Na⁺–K⁺-ATPase) has been demonstrated in excretory organs of Sepia officinalis, using a cytochemical procedure. In the renal appendages, both epithelia of the pancreatic appendages, the folded epithelium of the branchial heart appendage and the transport-active epithelium of the gill, the enzyme is localized exclusively in the basolateral cell membranes, i.e., the membranes of the basal labyrinth and the lateral plasma membranes. In addition, Na⁺–K⁺-ATPase is also located in the sarcolemma of the muscle fibres of the branchial heart. Distribution and localization of the enzyme is further substantiated by [³H]-ouabain autoradiography. The possible involvement of Na⁺–K⁺-ATPase in the excretion of ammonia and in ionic regulation in dibranchiate cephalopods is discussed.This study was supported by the Deutsche Forschungsgemeinschaft and is part of a doctoral dissertation     

Cr(VI)对脊尾白虾(Exopalaemon carinicauda)幼虾暴露和恢复期肝胰脏的SOD活性、MDA及MTs含量的影响

为了探索水体中Cr(VI)对脊尾白虾(Exopalaemon carinicauda)的毒性效应,通过Cr(VI)的暴露(15 d)和清水恢复实验(15 d),研究了Cr(VI)对脊尾白虾肝胰脏的SOD活性、MDA及MTs含量的影响。结果表明,通过15 d的暴露,5 mg·L-1(高浓度)、0.5 mg·L-1(低浓度)实验组肝胰脏的SOD均显著高于对照组水平(p0.05),15 d的清水恢复后,两个浓度实验组均能够恢复到对照组水平(p0.05)。MDA在暴露阶段呈现持续上升的趋势,且在15 d后两个浓度实验组MDA的含量均显著高于对照组水平(p0.05),15 d的清水恢复后,5 mg·L-1实验组的MDA含量依然显著高于对照组水平(p0.05),0.5mg·L-1实验组的MDA含量基本恢复到对照组水平(p0.05)。通过15 d的暴露,两个浓度实验组MTs的含量均显著高于对照组水平(p0.05),15 d的清水恢复后,两个浓度实验组MTs的含量均能够恢复到对照组水平(p0.05)。     

Reduced hypoosmoregulatory ability and alteration in gill chloride cell distribution in mature chum salmon (Oncorhynchus keta) migrating upstream for spawning

Osmoregulatory ability of mature chum salmon (Oncorhynchus keta) during spawning migration was examined by following the changes in gill Na⁺, K⁺-ATPase activity and in the distribution and morphology of chloride cells. Mature chum salmon caught in Otsuchi Bay, northern Honshu Island, Japan, died within 5 d in seawater (SW) in association with a marked increase in plasma osmolality, whereas the fish transferred to fresh water (FW) maintained plasma osmolality efficiently. Gill Na⁺, K⁺-ATPase activity decreased in both SW-maintained and FW-transferred fish. Well-developed chloride cells, identified by immunocytochemical staining specific for Na⁺, K⁺-ATPase, were present mainly in the filament epithelium of immature fish caught in the ocean. In mature fish caught in the bay, however, additional chloride cells were also found in the lamellar epithelium. The number of filament chloride cells decreased markedly in the mature fish both in SW and in FW, whereas the number of lamellar chloride cells was maintained. These results suggest that the loss of hypoosmoregulatory ability in mature chum salmon may be attributable to the decrease in filament chloride cells and associated decrease in gill Na⁺, K⁺-ATPase activity, and also that appearance of lamellar chloride cells may be preparatory to the forthcoming upstream migration. Received: 14 April 1997 / Accepted: 5 May 1997