Cadmium-induced antioxidant defense mechanism in freshwater teleost Oreochromis mossambicus (Tilapia)

Antioxidant defenses consisting of catalase, superoxide dismutase (SOD), xanthine oxidase (XOD), glutathione peroxidase (GPX), and glutathione S-transferase were estimated in liver and kidney of freshwater fish subjected to a sublethal concentration of cadmium chloride (Cd2+), i.e., 5 ppm. The aim of the study was to evaluate the role of antioxidant defenses during cadmium-induced oxidative stress. Significant elevations in liver and kidney of all of the above detoxification enzymes were evident from the 7th day onward, were maintained until the 15th day, and then decreased slightly on the 30th day of exposure to cadmium stress. Between the two tissues studied, liver recorded higher activity for all enzymes except GPX, which was elevated significantly in kidney (82.85%). Both liver and kidney recorded more or less similar increases of SOD (86.61% and 86.32%, respectively), and XOD (86.41% and 84.19%, respectively). The findings indicate that tissue glutathione-dependent enzymes as well as other antioxidant enzymes function in protection against Cd2+ toxicity and that these antioxidants provide a first line of defense against Cd2+ before the induction of any metallothionein synthesis occurs.     

Toxicity test of landfill leachate using Sarotherodon mossambicus (freshwater fish)

Landfill leachate was collected in March and July, 1984, at the Gin Drinkers' Bay Landfill Site, and the properties of the two leachates were examined. The leachate collected in March contained higher contents of total solid, ammonia, and metals than that collected in July. The leachates were treated with EDTA (10(-3) M) and Al2(SO4)3 (2 and 4 g/liter), alone and in combination. Addition of alum (2 g/liter) removed more than 60% of the phosphate content of the two leachates, and about 20 and 68% of total solid from leachates collected in March and July, respectively. Different concentrations of the leachates (untreated and alum-treated) were used to test the survival of tilapia, Sarotherodon mossambicus. The 96-hr LC50 for untreated leachates of March and July were 1.4 and 12%, respectively. The alum-treated leachates raised the 96-hr LC50 to 2.2 and 31.4%, accordingly.     

Interaction of potash and decis in the ecophysiology of a freshwater fish Oreochromis mossambicus

Interaction of potash and decis in the ecophysiology of a freshwater fish, Oreochromis mossambicus, was studied. It was found that 300, 550 and 700 mgL(-1) of potash were sublethal (LC(0)), median lethal (LC(50)), and toxic (LC(100)) to O. mossambicus for 96h exposure, respectively. For decis, 96 h LC(100,) LC(50), and LC(0) was 0.4, 0.25, and 0.1 mgL(-1), respectively. Sublethal concentrations of potash and decis were exposed to fishes individually and in combination for 28 days. The results revealed that the combined effect of these chemicals was more highly toxic to food intake, growth, and conversion efficiencies than the individual chemicals. The marker enzymes (acid phosphatase, alkaline phosphatase, aspartate transaminase, alanine transaminase) were also analyzed in blood, liver and muscle. The enzyme activities were decreased in liver and muscle. On the other hand, serum exhibited increased activities of marker enzymes. The results were tested statistically and interpreted accordingly.     

Ultrastructural changes in gills of Sarotherodon mossambicus treated with chicken manure

Sarotherodon mossambicus were fed a chicken manure (60%) supplementary diet for 4 weeks under laboratory conditions, and significantly higher (P less than 0.05) concentrations of Mn, Fe, Cu, Pb, and Zn were obtained in the gills of the treated fish. Ultrastructural changes including separation of the epithelium from the pillar cell system and subsequently increasing the blood-water barrier, necrosis of lamellar cells, collapse of lamellar blood spaces, and hyperplasia of interlamellar cells were found in the lamellae of the gills of the treated fish.     

Copper-induced changes in tissue enzyme activity in a freshwater mussel

Changes in enzyme activity levels are of great diagnostic value. Lysosomal membrane is often the target of injury by xenobiotics, resulting in destabilization. Variations in the activity of acid phosphatase (ACP) a marker enzyme, in gills and hepatopancreas of the freshwater mussel Lamellidens corrianus (Lea) exposed to different concentrations of copper for 24, 120, and 168 h are discussed. The aim was to determine if the metal caused any variation in enzyme activity in the two tissues studied and, if so, whether the length of exposure had any influence on enzyme activity. ACP activity was determined as described in Sigma Technical Bulletin No. 104 and expressed as micromoles of p-nitrophenol liberated per milligram of protein per hour. Both concentration of the metal and length of exposure were found to influence enzyme activity. Higher concentrations of metals are assumed to induce stress proteins like metallothioneins.     

Manganese-induced biochemical changes in growing versus adult rats

Manganese chloride was administered daily intraperitoneally to growing and adult rats for a period of 30 days to compare certain biochemical parameters in both groups of animals. Marked alterations in the levels of dopamine and norepinephrine in the brain was observed in manganese-treated growing rats. Furthermore, the contents of tyrosine, tryptophan in blood, liver, and brain have been significantly altered in these animals. Identical manganese administration to adult rats had no effect on the contents of tyrosine in liver and brain, nor tryptophan, and dopamine in the brain. Some of the parameters which were altered in the adult rats were less in magnitude compared to the growing animals. The experiments indicated higher susceptibility of the growing rats to the toxic effects of this metal.     

Experimental zinc deficiency in guinea-pigs: biochemical changes

1. Zinc deficiency was produced experimentally in guinea-pigs fed on a diet containing 1.25 mg Zn/kg diet over a period of 60 d. In addition, the response of the Zn-deficient (ZnD) animals to Zn supplementation was studied for 15 d. 2. In the ZnD group a significant reduction was found in serum Zn and protein concentrations and in alkaline phosphatase (EC 3.1.3.1; AP) activity from day 24 onwards. 3. Paper electrophoretic studies on serum revealed a significant decrease in relative values, as well as absolute values, of albumin and gamma-globulin and an increase in beta-globulin. 4. Albumin:globulin increased on day 24 but decreased significantly from day 48 onwards. 5. The kidney and testis of the ZnD group showed a reduction in Zn and protein contents, and AP activity. 6. Zn supplementation of the previously ZnD group resulted in marked although incomplete improvement in the biochemical indices studied.     

Effect of profenofos feeding on biochemical changes in chicken

The disruption of transaminases and phosphatases from the normal values denotes biochemical impairment and lesions of tissues and cellular function because they are involved in the detoxification process, metabolism and biosynthesis of energetic macromolecules for different essential function. The results of the present study revealed that feeding chicken in profenofos contaminated feed at levels of 50, 100 and 200 ppm for three weeks, resulted in a significant increase in the values of glutamic-pyruvic transaminase (GPT), glutamic oxaloacetic transaminase (GOT), Alkaline phosphatase (A.P.) and cholesterol, especially at levels of 100 and 200 ppm. Upon return of normal feed free from profenofos for 10 days, these values decreased gradually but not to normal and the decreases were not significant.     

铅诱导的大鼠脑星形胶质细胞内质网应激反应

目的研究慢性铅暴露对原代培养的大鼠脑星形胶质细胞增殖、形态、细胞周期以及葡萄糖调节蛋白78(glucose regulated proteins,GRP78)、生长抑制DNA损伤诱导因子(growth arrest and DNA damage inducible gene,GADD153)和细胞周期蛋白D1(CyclinD1)表达的影响,探讨脑星形胶质细胞中铅所诱导的内质网应激反应。方法出生1～4d Wistar大鼠脑星形胶质细胞原代培养并传代,分为对照组和染毒组。分别应用四甲基偶氮唑蓝(methyl thiazolyl tetrazolium,MTT)、流式细胞术、倒置显微镜观察1.0μmol/L乙酸铅染毒细胞增殖率、细胞周期和形态的变化。利用Western blotting检测乙酸铅对星形胶质细胞GRP78、GADD153和CylcinD1表达的影响。结果染铅30d后细胞增殖率下降50.8%。染铅8、12、15和30d后,停留在G1期的细胞数由(58.64±1.75)%分别增加至(69.81±1.56)%、(70.80±1.27)%、(90.59±1.25)%和(80.9±1.11%)。1.0μmol/L乙酸铅呈时间依赖性促进GRP78表达,抑制CyclinD1表达,差异有统计学意义(P0.05),而GADD153的表达无显著性改变。结论铅可使原代培养的大鼠脑星形胶质细胞发生增殖抑制、细胞周期停滞、GRP78表达上调、CyclinD1表达下调等一系列应激反应。     

Histological changes in the liver of Oreochromis mossambicus (Cichlidae) after exposure to cadmium and zinc

The toxic effects, of two heavy metals, cadmium (Cd) and zinc (Zn), on the histology of the liver of the southern African freshwater fish Oreochromis mossambicus, were investigated. The goal was to identify whether metal concentrations and exposure period influence the degree and nature of histological changes in the liver of exposed fish. Selected fish were exposed to a mixture of 5% concentrations of the LC₅₀ of cadmium and zinc and to a mixture of 10% concentrations of the LC₅₀ of cadmium and zinc, over both short- and long-term exposure periods. Similar histological changes occurred in the livers of specimens exposed to both 5% and 10% concentrations, indicating a definite toxic response to both the metal concentrations. These histological changes included hyalinization, hepatocyte vacuolation, cellular swelling, and congestion of blood vessels. The intensity of these histological changes was, however, influenced by the extent of the exposure period.     

Some biochemical changes in lenses of riboflavin deficient rats.

In order to better understand the role of riboflavin in the lens, we investigated the lenses of rats fed on a riboflavin deficient diet for 7 weeks to determine changes in the inactivation of cortisol, the glucose-6-phosphate dehydrogenase (G-6-PD) activity and the histidine or 5-hydroxytryptophan decarboxylase activity. The cortisol-binding capacity and G-6-PD activity in the lenses of rats fed on a riboflavin deficient diet were found to be decreased as compared with a control. Histidine decarboxylase activity was found twice as high in the riboflavin deficient rats as in the normal lenses however, 5-hydroxytryptophan decarboxylase was somewhat decreased. These findings show that catabolical changes in the metabolism of rat lenses are induced comprehensively by feeding on a riboflavin deficient diet in the same manner as changes are seen in the cataractous lens.     

Predicting chemical contaminants in freshwater sediments through the use of historical biochemical endpoints in resident fish species

Previous studies in Bayou Bartholomew, Arkansas, USA, indicated significant relationships between the individual health of fish sampled from 13 sites and specific biochemical responses. Evaluation of several biochemical endpoints in 1994 indicated the bioavailable occurrence of either polychlorinated biphenyl (PCB) congeners or metals. To evaluate this possibility, in December 2000, sediments were collected at four sites on Bayou Bartholomew, where fish, collected in July 1994, had previously demonstrated the highest hepatic cytochrome P4501A (CYP1A) and heme oxygenase (HO) expression. Samples were analyzed for 89 PCB congeners, 18 organochlorine pesticides, and 25 metals. Total PCB concentrations ranged from 6.5 to 704 ng/g dry weight. Although several PCB congeners were observed, 81, 87, 99, 114, and 153 represented up to 33, 22, 29, 92, and 55% of the sum of PCBs from the four sites, respectively. Total organochlorine pesticide concentrations ranged from undetectable to 53.2 ng/g dry weight. Lindane, heptachlor, dachtal, dieldrin, hexachlorobenzene, dichlorodiphenyltrichloroethane (DDT), dichlorodiphenyl ethane (DDE), and dichlorodiphenyl dichloroethane (DDD) isomers were detected in most samples. Detected organophosphate pesticides included malathion, chlorpyrifos, and dimethoate. Both p,p'-DDE and p,p'-DDD were the most predominant of the pesticides measured (0.5-14.1 and 0.7-58.5 ng/g dry wt). All metal concentrations analyzed were below sediment quality guideline values. Metals exceeding national average concentrations were cobalt (2 of 4 [2/4] sites), copper (1/4), molybdenum (4/4), antimony (3/4), selenium (4/4), tin (4/4), and zinc (1/4). These results were consistent with PCBs being causative agents for the biochemical and adverse individual responses observed in fish sampled from this waterway.