Immunohistochemically detected ontogeny of prolactin and growth hormone cells in the African catfish Clarias gariepinus

The chronological appearance of selected endocrine cells in the pituitary of African catfish Clarias gariepinus (Burchell, 1822) was studied morphologically, histologically and immunohistochemically by using antisera raised against catfish growth hormone (cgGH) and recombinant tilapia prolactin I (tPRL). cgGH- and tPRL-like immunoreactive cells were visible from day 1 post fertilisation (hatching) throughout the juvenile and the adult stage. From 1 to 90 days after hatching, the larval pituitary is oval in shape with a distinctly shaped rostral pars distalis, proximal pars distalis and pars intermedia. From day 120 onwards allometric growth of the rostral and proximal pars distalis extended the prolactin and growth hormone cells anteriorily and posteriorily, respectively. Size and activity of the prolactin and growth hormone cells, measured by the ratio of cell surface to nuclear surface remained constant until day 40 and showed a growth spurt thereafter. Growth hormone content, measured with a catfish-specific radio-immunoassay from hatching until 60 h post hatching, increased exponentially between 30 and 60 h.     

One-step immunoaffinity purification and partial characterization of hypophyseal growth hormone from the African catfish, Clarias gariepinus (Burchell)

Growth hormone (GH) was purified from African catfish (Clarias gariepinus) pituitary extracts in a single step by use of immunoaffinity chromatography. A monoclonal antibody to chicken GH, which labels the catfish hypophyseal somatotropes in immunocytochemistry, was coupled to CNBr-activated Sepharose, and crude alkaline pituitary extracts were run over the immunoadsorbent. Reversed-phase high-performance liquid chromatography analysis of the eluted material suggested heterogeneity, whereas silver staining upon SDS-polyacrylamide gel electrophoresis showed one single band with an estimated molecular weight between 22,000 and 23,000 Da. Matrix-assisted laser desorption ionization time-of-flight mass spectrometry analysis of the same preparation revealed the presence of several components with molecular weights ranging from 20,170 to 20,900 Da. The amino terminus of the protein was homogeneous, and the first 50 residues matched the proposed sequence of GH from two other siluran species (Ictalurus punctatus and Pangasius pangasius), except for one substitution at position 3. These data unequivocally confirm the identity of the purified molecule as suggested by immunochemical evidence. The bioactivity of the GH preparation was demonstrated by the short-term effect of GH on T₃ plasma levels in juvenile catfish.     

A note on alarm cues in juvenile African catfish, Clarias gariepinus Burchell: Indications for opposing behavioural strategies

Following exposure of African catfish to alarm cues, a relationship (r_p = 0.60, N = 10, P = 0.07) between feed efficiency (measured as residual feed intake) and the change in percentage of time spent swimming in response to damage-released alarm cues was observed. Feed-efficient animals responded with a decrease in percentage of time spent swimming (P < 0.05) whereas feed-inefficient animals responded with an increase in percentage of time spent swimming (P < 0.05). This study shows opposing behavioural strategies in African catfish in response to damage-released alarm cues being related to feeding efficiency.     

Steroid glucuronides as male pheromones in the reproduction of the African catfish Clarias gariepinus—a brief review

After ovulation, female African catfish are strongly attracted by the odor of male conspecifics. This attraction depends on the presence of the seminal vesicle, a part of the male reproductive organs. Removal of the seminal vesicle illustrates this fact. A low dose of seminal vesicle fluid, added to the water, appears to be highly attractive for catfish which have ovulated. Fractionation of the fluid and testing of the different fractions shows that steroid glucuronides could be responsible for the attraction. These steroid glucuronides can be identified with gas chromatographic-mass spectrometric analysis. A mixture of glucuronides, prepared to resemble the composition of the seminal vesicle fluid, evokes a dose-dependent attraction. The most potent odorant, observed by measuring electrical responses from the olfactory epithelium and from the olfactory tract appears to be 3α,17α-dihydroxy-5β-pregnan-20-one-3α-glucuronide.     

Reconstruction of Electric Discharge Patterns and Electrogenesis Mechanism in African Sharptooth Catfish Clarias gariepinus (Clariidae,Siluriformes)

Doklady Biological Sciences - Electrical discharges (EDs) in the African sharptooth catfish Clarias gariepinus were studied. Irregular monopolar EDs, lasting for 8–10 ms and longer, and more...     

Toxicity of Buprofezin on the Survival of Embryo and Larvae of African Catfish,Clarias gariepinus (Bloch)

Buprofezin is an insect growth regulator and widely used insecticide in Malaysia. The present study evaluated the toxic effects of buprofezin on the embryo and larvae of African catfish (Clarias gariepinus) as a model organism. The embryos and larvae were exposed to 7 different concentrations (0, 0.05, 0.5, 5, 25, 50 and 100 mg/L) of buprofezin. Each concentration was assessed in five replicates. Eggs were artificially fertilized and 200 eggs and larvae were subjected to a static bath treatment for all the concentrations. The mortality of embryos was significantly increased with increasing buprofezin concentrations from 5 to 100 mg/L (p< 0.05). However, the mortality was not significantly different (p<0.05) among the following concentrations: 0 (control), 0.05, 0.5 and 5 mg/L. Data obtained from the buprofezin acute toxicity tests were evaluated using probit analysis. The 24 h LC₅₀ value (with 95% confidence limits) of buprofezin for embryos was estimated to be 6.725 (3.167-15.017) mg/L. The hatching of fish embryos was recorded as 68.8, 68.9, 66.9, 66.4, 26.9, 25.1 and 0.12% in response to 7 different concentrations of buprofezin, respectively. The mortality rate of larvae significantly (p<0.05) increased with increasing buprofezin concentrations exposed to 24-48 h. The 24 and 48 h LC₅₀ values (with 95% confidence limits) of buprofezin for the larvae was estimated to be 5.702 (3.198-8.898) and 4.642 (3.264-6.287) mg/L respectively. There were no significant differences (p>0.05) in the LC₅₀ values obtained at 24 and 48 h exposure times. Malformations were observed when the embryos and larvae exposed to more than 5 mg/L. The results emerged from the study suggest that even the low concentration (5 mg/L) of buprofezin in the aquatic environment may have adverse effect on the early embryonic and larval development of African catfish.     

Biochemical and Ultrastructural Analysis of Ovaries of African Sharptooth Catfish,Clarias gariepinus (Burchell) Exposed to Pollutants from River Yamuna in Delhi Region,India

Biology Bulletin - The increasing level of pollution in River Yamuna has turned it into sewage carrying drain, thus, distressing aquatic life as the river traverses downstream from Wazirabad (entry...     

Cryopreservation of Rainbow Trout (Oncorhynchus mykiss) Blastomeres: Influence of Embryo Stage on Postthaw Survival Rate

The cryopreservation of isolated fish blastomeres is likely to provide a valid alternative to embryo cryopreservation, the results of which are still discouraging. A repeatable technique for the cryopreservation of rainbow trout blastomeres has been established and the effect of embryonic developmental stage on freezing tolerance evaluated. Embryos at Ballard 6A, 6B, and 6C stages were dechorionated and left to dissociate in a Ca2+- and Mg2+-free medium. Cryoprotection was provided by step-wise addition of 1.4 M 1,2-propanediol. Cells were loaded into the middle of 250-μl straws and slowly frozen to -80 degreesC before being plunged into LN2. A low thawing rate was adopted, followed by step-wise removal of the cryoprotectant. Morphological evaluation was by microscopy and video recording. Metabolic activity and survival rate were determined by FDA and PI staining, by recovery of the ability to reassociate after 24 h culture in Leibovitz L15 + 2% Ultroser, and by measuring DNA synthesis in 6B cells by the method of BrdU incorporation. Survival rates were 53 +/- 9.3, 88 +/- 1.7, and 95 +/- 0.5% for stage 6A, 6B, and 6C cells, respectively. While 6A cells reassociated into clumps of cells, 6B and 6C cells formed holoblastic morulas in 24 h; proliferation of 6B cells was comparable to fresh control cells. The relationship between freezing tolerance and the physiological events occurring during early embryonic development is discussed in light of these results and conclusions are drawn that envisage the transfer of frozen-thawed blastomeres into recipient embryos. Copyright 1998 Academic Press.     

Factors Affecting the Outcome of Artificial Insemination Using Cryopreserved Spermatozoa in the Giant Panda (Ailuropoda melanoleuca)

Artificial insemination (AI) is an important component of captive breeding programs for endangered species, such as the giant panda. The panda has been the subject of increasingly successful captive breeding programs involving a compilation of assisted breeding techniques, including AI using cryopreserved spermatozoa. AI implementation is currently hampered by a lack of understanding of the factors that may cause failure. We investigated factors influencing the probability of success of AI for 14 giant panda females housed at the China Center for Research and Conservation of the Giant Panda (CCRCGP) inseminated in a total of 20 instances using cryopreserved spermatozoa from 11 males currently residing in 6 different captive breeding institutions. One of the pandas was the oldest giant panda female to ever successfully conceive from AI (20.5 years old). The success of AI was significantly affected by the timing of AI in relationship to both timing of peak urinary estrogen of the female and percent decline in urinary estrogen between the peak level and the first AI attempt. Our results suggest that the window for successful AI in giant pandas may be narrower than previously suspected, although individual differences in rates of decline in urinary estrogen may reflect some degree of variation in this crucial window across females. Our results are consistent with recent research on pandas and other species that demonstrates the efficacy of cryopreserved spermatozoa for AI and highlights the need for more in‐depth analysis of factors related to female physiology that may influence its success. Zoo Biol 31:561‐573, 2012. © 2011 Wiley Periodicals, Inc.     

Cryopreservation of Rainbow Trout (Oncorhynchus mykiss) Blastomeres: Influence of Embryo Stage on Postthaw Survival Rate

The cryopreservation of isolated fish blastomeres is likely to provide a valid alternative to embryo cryopreservation, the results of which are still discouraging. A repeatable technique for the cryopreservation of rainbow trout blastomeres has been established and the effect of embryonic developmental stage on freezing tolerance evaluated. Embryos at Ballard 6A, 6B, and 6C stages were dechorionated and left to dissociate in a Ca²⁺- and Mg²⁺-free medium. Cryoprotection was provided by step-wise addition of 1.4 M 1,2-propanediol. Cells were loaded into the middle of 250-μl straws and slowly frozen to −80°C before being plunged into LN₂. A low thawing rate was adopted, followed by step-wise removal of the cryoprotectant. Morphological evaluation was by microscopy and video recording. Metabolic activity and survival rate were determined by FDA and PI staining, by recovery of the ability to reassociate after 24 h culture in Leibovitz L15 + 2% Ultroser, and by measuring DNA synthesis in 6B cells by the method of BrdU incorporation. Survival rates were 53 ± 9.3, 88 ± 1.7, and 95 ± 0.5% for stage 6A, 6B, and 6C cells, respectively. While 6A cells reassociated into clumps of cells, 6B and 6C cells formed holoblastic morulas in 24 h; proliferation of 6B cells was comparable to fresh control cells. The relationship between freezing tolerance and the physiological events occurring during early embryonic development is discussed in light of these results and conclusions are drawn that envisage the transfer of frozen-thawed blastomeres into recipient embryos.     

Nomenclatural changes resulting from the transfer of tropical African Sarcostemma to Cynanchum ( Apocynaceae : Asclepiadoideae )

Summary  Four species of tropical African Sarcostemma are transferred to Cynanchum together with two subspecies of S. viminale. In addition, Sarcostemma mulanjense is reduced to subspecific rank under C. viminale.     

Successful Recovery of Motility and Fertility of Cryopreserved Cane Toad (Bufo marinus) Sperm

The recent decline and extinction of amphibian species is a worldwide phenomenon without an identified cause or solution. Assisted reproductive technologies, including sperm cryopreservation, are required to manage endangered amphibian species and preserve their genetic diversity. This study on the Anuran amphibian (Bufo marinus) was undertaken to determine the feasibility of cryopreservation of amphibian sperm. Sperm suspensions for cryopreservation were prepared by macerating testes in cryoprotective additives of 10% (w/v) sucrose or 10% (w/v) sucrose containing either 10, 15, or 20% (v/v) glycerol or 10, 15, or 20% (v/v) dimethyl sulfoxide (Me₂SO). Suspensions were then cooled to −85°C using a controlled rate cooler, stored in LN₂, and thawed in air. The motility and fertilization rate of cryopreserved suspensions and unfrozen control suspensions in Simplified Amphibian Ringer were compared. Sucrose alone had no cryoprotective effect. All other treatments showed varying degrees of recovery of motility and fertilizing capacity. High rates of recovery of motility and fertilizing capacity were observed with 15% Me₂SO (68.9 ± 3.8 and 60.5 ± 4.7%) and 20% glycerol (58.0 ± 5.9 and 81.4 ± 4.3%), respectively. Motility and fertilization rates were similar with Me₂SO but diverged with glycerol as cryoprotectant. The data demonstrate the feasibility of using sperm cryopreservation with amphibian species.     

The Effect of Drying Rate on the Survival of Three Desiccation-tolerant Angiosperm Species

The effect of drying rate on the survival of three angiospermresurrection plants, Craterostigma wilmsii (homoiochlorophyllous),Xerophyta humilis (poikilochlorophyllous) and Myrothamnus flabellifolius(homoiochlorophyllous) was examined. All species survived slowdrying, but only C. wilmsii was able to survive rapid drying.C. wilmsii was rapidly able to induce protection mechanismssuch as folding of cell walls to prevent mechanical stress andcurling of leaves to minimize light stress, and thus survivedfast drying. Rapid drying of X. humilis andM. flabellifoliusappeared to allow insufficient time for complete induction ofprotection mechanisms. In X. humilis, there was incomplete replacementof water in vacuoles, the photosynthetic apparatus was not dismantled,plasma membrane disruption occurred and quantum efficiency ofphotosystem II (F_V/F_M) did not recover on rehydration. Rapidlydried leaves of M. flabellifolius did not fold tightly againstthe stem and F_V/F_Mdid not recover. Ultrastructural studies showedthat subcellular damage incurred during drying was exacerbatedon rehydration. The three species co-occur in environments inwhich they experience high desiccation pressures. C. wilmsiihas few features to retard water loss and thus the ability forrapid induction of subcellular protection is vital to survival.X. humilis and M. flabellifolius are able to retard water lossand protection is acquired relatively slowly. Copyright 1999Annals of Botany Company Chlorophyll fluorescence, Craterostigma wilmsii, drying rate, Myrothamnus flabellifolius, resurrection plant, ultrastructure, Xerophyta humilis.     

Introduction of the African Catfish Clarias gariepinus (BURCHELL, 1822) into Southern Brazil

We record here the introduction of the African catfish Clarias gariepinus into the Guaraguaçu River basin in Paraná State, Brazil, an area with an extremely rich endemic fish fauna, including many catfishes. C. gariepinus was introduced as escapees from ponds built for recreational angling. These catfishes are very large and hard predators, thus posing serious potential for impact on the native fish fauna. The impact of C. gariepinus needs study with emphasis on finding means for controlling its spread.     

The genus Setulipes (Marasmiaceae) in Madagascar and the Mascarenes, including a key to other African taxa

The authors report first records for the genus Setulipes in Madagascar, with the presence of Setulipes cf. hakgalensis and two new species, Setulipes funaliformis and S. moreaui, as well as a new species from Mauritius: S. mauritiensis. A key to these taxa, as well as to other African species, is supplied.     

Mutagenic and physiological responses in the juveniles of African catfish, Clarias gariepinus (Burchell 1822) following short term exposure to praziquantel

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.     

提高圈养大熊猫仔兽存活率的研究

1998～2001年,对提高圈养大熊猫仔兽存活率进行研究,采用了母兽育幼、人工辅助育幼、保姆育幼、人工育幼等多种方法,特别是模仿大熊猫母兽的育幼行为和活动以及用人工巢进行人工育幼。人工巢制作简单,操作方便,育幼时的温度、湿度及呼吸的新鲜空气与母兽育幼环境近似,也便于科技人员观察、抚摩,促进幼仔身体活动及护理幼仔。采集母兽的初乳及常乳饲喂;抽取健康母兽的血液制成口服血浆,适量喂仔;用美国产的两种奶粉配制的人工奶,代替母兽常乳收到良好的育幼效果。在本项研究的4年中,将卧龙大熊猫育幼成活率由54．16％平均提高到90．32％,创大熊猫育幼史的最高水平,为大熊猫的迁地保护提供了新的应用技术和方法。     

The Effect of Antifreeze Glycoproteins on Survival of Fish Spermatozoa under the Conditions of Long-Term Storage at 4°C

It was already shown that antifreeze glycoproteins isolated from the blood of fish occurring in circumpolar regions inhibited the growth of ice crystals both in vitro and in vivo. When the spermatozoa were frozen to liquid nitrogen temperature, addition of antifreeze glycoproteins to cryoconserving media made it possible to decrease twofold the concentration of the synthetic cryoprotector dimethylsulfoxide without the loss and even with a certain increase in the number of viable spermatozoa. This effect was observed in the case of combined, rather than separate, addition of the fraction of weakly active (low molecular weight) and active (high molecular weight) antifreeze glycoproteins. Here, we studied the effect of antifreeze glycoproteins on the survival of carp spermatozoa under storage at 4°C for varying periods of time. In the presence of total fraction of low and high molecular weight antifreeze glycoproteins (2 and 10 mg/ml) added in a physiological proportion (3 : 1), the survival of spermatozoa increase but this increase did not depend linearly on the medium concentration of protein. Low and high molecular weight antifreeze glycoproteins added separately (10 mg/ml) either did not affect or slightly affected the preservation of cells. The hypothermic effect of antifreeze glycoproteins in water was significantly higher than in a medium with salt activator.     

温度对拟目乌贼幼体日生长率和存活率的影响

以温度为单因素变量,在人工饲养环境中,分析水温对拟目乌贼幼体日生长率与存活率的影响。实验结果表明,当水温处于28.1～32℃之间时,拟目乌贼幼体的日生长率与水温呈正相关关系;当水温处于32～32.67℃时,拟目乌贼幼体的日生长率与水温呈负相关关系;当水温处于29.5～32.6℃时,拟目乌贼幼体不易出现幼体死亡(死亡率<6.25%),适宜拟目乌贼幼体的存活;而当水温处于32.3～34℃之间时,拟目乌贼幼体出现了13.16%～61.16%的幼体死亡,不适宜拟目乌贼幼体的存活。实验结果表明,当水温处于29.5～32℃之间时,拟目乌贼幼体的存活率高(存活率>93.75%),且日生长率处于0.24%～1.76%,适宜拟目乌贼幼体的存活。