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排序方式: 共有106条查询结果,搜索用时 15 毫秒
21.
Christopher Dididgwu Nwani Macniel Chijioke Nnaji Stanley Ndubuisi Oluah Paul Chinedu Echi Helen Ogochukwu Nwamba Ogbonnaya Egbe Ikwuagwu Malachy Nwigwe Okechukwu Ajima 《Tissue & cell》2014
Praziquantel (PZQ) is an acylated quinoline-pyrazine originally developed for veterinary application but now one of the most used anti-helminthic drugs for treatment of certain trematodes and cestodes in both human and other animals. The present study investigated the mutagenic and physiological responses in the juveniles of African catfish, Clarias gariepinus following short term exposure to praziquantel. Based on the 53.52 mg/l 96 h LC50 of PZQ obtained, two sublethal concentrations of 5.35 and 10.70 mg/l of the drug were selected and fish were exposed to these concentrations and control for 15 days. Micronuclei induction in the peripheral blood of PZQ-exposed fish was highest on day 10 but the fish morphological parameters were not affected. The packed cell volume (PCV) was significantly reduced (p < 0.05) from day 5 while red blood cells (RBC) and hemoglobin (Hb) significantly declined (p < 0.05) on day 15. Macrocytic anemia was observed on day 1 of study and thereafter microcytic anemia developed on day 5 of study. The white blood cell (WBC) was significantly (p < 0.05) elevated from day 10 of exposure while values of mean cellular volume (MCV), mean cellular hemoglobin (MCH) and mean cellular hemoglobin concentration (MCHC) were not significantly different (p > 0.05) from the control. Alanine aminotransferase (ALT), aspartate aminotransferase (AST) and glucose levels significantly increased while protein reduced (p < 0.05) throughout the exposure period but a mixed trend was observed in the leukocyte differentials. PZQ should be used with caution as sublethal exposure elicited micronucleus induction and alterations of hematological and biochemical parameters in the fish. 相似文献
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人工湿地对胡子鲇养殖水体循环净化的研究 总被引:1,自引:0,他引:1
以大型观光植物美人蕉-砾石为基础的垂直流人工湿地对胡子鲇养殖水体进行净化处理和回流使用,在胡子鲇养殖中测定了水体主要水质指标的变化,表明人工湿地对养殖水体净化效果显著,养殖期间BOD5、COD、TN的平均去除率分别为81.77%、55.55%和65%,净化后水质部分符合渔业用水标准,可以循环利用.对照池水体由于BOD5、COD、TN得不到去除而持续增加,混浊度显著高于实验池,并出现水华.这种水体循环养殖模式具结构简单和易推广等优点. 相似文献
24.
H. E. Sharp-Baker J. Peute J. H. B. Diederen L. Brokken 《Cell and tissue research》1995,280(1):113-122
The possible function of globules and irregular membrane-bound masses in the gonadotropin cells of the pituitary of Clarias gariepinus was studied. Strong secretory stimulation led to the disappearance of the secretory granules from gonadotropin cells but globules and irregular masses remained present. Acid phosphatase was detected enzyme-cytochemically in both globules and irregular masses. Radiolabelling with tritiated amino acids followed by autoradiography demonstrated that globules received radioactive material after secretory granules. The latter received radioactive material within 75 min of administration of radioactive amino acids but globules and irregular masses did not. Although some globules became radioactively labelled within 24 h of the administration of radioactive amino acids, irregular masses remained unlabelled during this period. Secretory granules reacted positively with antisera against and gonadotropin subunits, whereas globules and irregular masses only reacted with the antiserum against the subunit. A moderate anti-7B2 immunoreactivity was demonstrated in secretory granules and globules, whereas irregular masses labelled strongly. The combined cytological results indicate that globules and irregular masses are degradative, possibly crinophagic structures which develop by fusional events from secretory granules to globules and then to irregular masses. 相似文献
25.
Using four different sperm types from brown trout Salmo trutta fario (Salmonidae), chub Leuciscus cephalus (Cyprinidae), burbot Lota lota (Gadidae) and African catfish Clarias gariepinus (Clariidae) the effect of inorganic (cadmium, copper, mercury, lead, zinc and nitrite) and organic (cyclohexane and 2,4‐dichlorophenol) environmental pollutants on sperm motility was investigated. Spermatozoa were activated in double distilled water containing the different test substances and the motility was compared to controls of similar pH. From the investigated motility variables the sperm motility rate and swimming velocity reacted most to the environmental pollutants whereby the changes depended on the species and on the test substance. African catfish spermatozoa were the most resistant, chub and burbot spermatozoa showed medium resistance and brown trout spermatozoa were the most sensitive to the pollutants. With exception of 2,4‐dichlorophenol and zinc the effective concentrations of the tested pollutants exceeded the recommendation for surface waters 100–10·000‐fold and were in a range lethal for the fish themselves. Therefore, it was concluded that fish sperm motility is not a suitable marker for risk assessment of environmental pollutants. 相似文献
26.
Summary The effects of carp pituitary suspension (CPS) and 11-desoxycorticosterone-acetate (DOCA) on 3-hydroxysteroid dehydrogenase (3-HSD) and glucose-6-phosphate dehydrogenase (G6PD) activity in the ovary of Clarias lazera are described. Strong 3-HSD and G6PD activities are localized in the stroma, of both control and treated fish. A single CPS injection stimulates 3-HSD activity in the granulosa of postvitellogenic, maturing and postovulatory follicles, but DOCA has no such effect on the postvitellogenic and maturing follicles, and only stimulates a weak response in the postovulatory ones. 相似文献
27.
When treated with detergent club cells showed degenerative changes and released their contents to plug the intercellular spaces. This mechanism could act as an efficient protective barrier substantiating the role of club cells in assisting fish to overcome adverse conditions. A general decrease in the dimensions of club cells was associated with discharge of their contents. The appearance of juvenile club cells reflected their differentiation in response to increased demands to meet the challenge. Increases in the number of club cells indicated the differentiation of these cells at a rate faster than their degeneration. Localization of glycogen in club cells at the start of detergent treatment and, in general, its absence later and, in both control and juvenile club cells, is discussed in relation to the metabolic status of the cells. No marked shift was observed in the mucopolysaccharide and protein moieties of club cells. 相似文献
28.
Static tests were employed to assess the acute toxicity of the water-soluble fraction (WSF) of spent automotive lubricating oil (of mixed SAE grades) on Clarias gariepinus, a freshwater fish commonly cultured in Nigeria. Median lethal concentrations (LC50) of the WSF were found to decrease as a function of exposure time from 690+/-21 (after 24 h) to 513+/-58 mg/l (after 96 h). The characteristics of the WSF such as mean acidity (pH 6.6), turbidity (40 NTU), total dissolved solids (TDS; 40 mg/l) and significantly reduced (P<0.05) dissolved-oxygen (DO) values (1.44 mg/l) were not compliant with existing standards set for discharged effluents. The solubility of the detected straight-chain aliphatics ranked as C14>C16>C32>C18>C28; that of the simple aromatics was ortho-xylene>para-xylene; and that of the polyaromatic hydrocarbons (PAHs) was acenaphthylene>9H-fluorene>naphthalene>anthracene>phenanthrene>chrysene>benzo[k]fluoranthene>benzo[a]pyrene>benzo[b]fluoranthene, most of which being serious carcinogens. These oil constituents and the overall physico-chemical properties of the WSF are expected to act synergistically on the test organism (C. gariepinus), eliciting the quantal responses observed. The toxicity of the WSF points to the base constituent, oxidative degradation, and mechano-chemical reactions associated with aged crankcase oils. These oils, therefore, should definitely no longer be disposed into water streams or landscape, not even at sub-lethal concentrations, because of the inherent toxicity of their soluble fractions and the associated danger of bioaccumulation. 相似文献
29.
Arafa SZ El-Naggar MM El-Abbassy SA Stewart MT Halton DW 《Parasitology international》2007,56(4):297-307
Phalloidin fluorescence technique, enzyme cytochemistry and immunocytochemistry in conjunction with confocal scanning laser microscopy were used for the first time to describe the nervous and muscle systems of the viviparous monogenean parasite, Gyrodactylus rysavyi inhabiting the gills and skin of the Nile catfish Clarias gariepinus. The body wall muscles are composed of an outer layer of circular fibres, an intermediate layer of paired longitudinal fibres and an inner layer of well-spaced bands of diagonal fibres arranged in two crossed directions. The musculature of the pharynx, intestine, reproductive tract and the most prominent muscles of the haptor were also described. Two characteristic muscular pads were found lying in the anterior region of the haptor in close contact with the hamuli. To each one of these pads, a group of ventral extrinsic muscles was connected. The role of this ventral extrinsic muscle in the body movement was discussed. The mechanism operating the marginal hooklets was also discussed. The central nervous system (CNS) consists of paired cerebral ganglia from which three pairs of longitudinal ventral, lateral and dorsal nerve cords arise. The nerve cords are connected at intervals by many transverse connectives. The CNS is better developed ventrally than dorsally or laterally and it has the highest reactivity for all neuroactive substances examined. Both the central and the peripheral nervous system (PNS) are bilaterally symmetrical. Structural and functional correlates of the neuromusculature of the pharynx, haptor and reproductive tracts were explained. The results implicated acetylcholine, FMRFamide-related peptides (FaRPs) and serotonin in sensory and motor function. The results were compared with those of the monogeneans Macrogyrodactylus clarii and M. congolensis inhabiting the gills and skin respectively of the same host fish C. gariepinus. 相似文献
30.