The influence of cysteine and taurine on microscopic-oxidative stress parameters and fertilizing ability of bull semen following cryopreservation

Oxidative stress significantly damages sperm functions such as motility, functional integrity, endogenous antioxidant enzyme activities and fertility due to lipid peroxidation induced by reactive oxygen species (ROS). The aim of this study was to determine the effects of antioxidants such as taurine and cysteine in Bioxcell^® extender on standard semen parameters, fertilizing ability, lipid peroxidation (LPO) and antioxidant activities comprising reduced glutathione (GSH), glutathione peroxidase (GSH-Px), catalase (CAT) and superoxide dismutase (SOD) after the cryopreservation/thawing of bull semen. Nine ejaculates for each bull were included in the study. Three groups, namely taurine (2 mM), cysteine (2 mM), and control, were designed to analyze the antioxidants in Bioxcell^®. Insemination doses were processed so that each 0.25-ml straw contained 15 × 10⁶ sperm.The addition of cysteine led to higher motility, compared to the other groups (P < 0.001). Cysteine showed a greater protective effect on the percentages of acrosome damage and total abnormalities in comparison to the other groups (P < 0.001). No significant differences were observed in hypo-osmotic swelling test (HOST), following supplementation with antioxidants during the freeze-thawing process. No significant difference was observed in non-return rates among groups. In biochemical assays, the additives did not show effectiveness on the elimination of malondialdehyde (MDA) formation and maintenance of GSH and GSH-Px activities, when compared to controls. CAT activity (35.1 ± 8.1 kU/g) was demonstrated to be significantly higher upon the addition of 2 mM taurine (P < 0.001), while the level of MDA increased, indicating oxidative stress in this group. SOD activity (21.4 ± 2.9 U/g protein) was significantly elevated in the group with cysteine, compared to the other groups (P < 0.001).     

Threats to Fish and Fisheries of Kangsabati Reservoir,West Bengal,India

Fishes belonging to the Orders Beloniformes, Cypriniformes, Perciformes, Siluriformes and Synbranchiformes are usually found in the Kangsabati reservoir of West Bengal, India. In recent years among the trapped fishes fishermen failed to get certain fish species which were available to them in the last decade. This prompted us to conduct a survey of ichthyofauna of the said reservoir in respect to the water parameters, keeping in view the anthropogenic activity-induced pollution scenario. It is revealed that the fishes belonging to the species Xenentodon cancila, Nemacheilus savona, Sillaginopsis panijus, Pangasius sutchi, Colisa sota, Mystus cavasius, Mystus seenghala and Mastacembelus armatus are completely absent in the survey area. It is most likely that the eutrophication-induced causes especially, variations in composition and density of plankton as well as the undesirable changes in physical and chemical properties of the water have forced these fishes to migrate elsewhere.     

Sertoli cells in the testis and epithelium of the ductuli efferentes are targets for 3H 1,25 (OH)2 vitamin D3

Summary Evidence from results of autoradiographic studies in mice indicates that nuclei of Sertoli cells and of epithelial cells in the ductuli efferentes contain receptors for 1,25(OH)₂ vitamin D₃.     

Estrogen target cells in the pituitary of platyfish,Xiphophorus maculatus

Summary The distribution of estradiol-concentrating cells in the pituitary of the platyfish, Xiphophorus maculatus, is studied after the injection of ³H estradiol-17 by thaw-mount autoradiography. Autoradiograms prepared 2–8 h after the injection show nuclear concentration of radioactivity in certain cells of the proximal pars distalis, while no nuclear labeling is found in cells of the rostral pars distalis, pars intermedia and pars nervosa. Radioactively labeled cells are identified as gonadotropes by a combined technique of thaw-mount autoradiography and immunoperoxidase staining with antiserum to ovine LH. Approximately 80% of the immunoreactive LH cells show a concentration of radioactivity in their nuclei. These observations indicate that in teleosts, as in mammals, estradiol has a direct effect on pituitary gonadotropes.Supported by PHS grant NS09914. The authors are grateful to Dr. D.G. Humm for providing the platyfish     

Sources of organic matter for intertidal consumers on Ascophyllum-shores (SW Iceland): a multi-stable isotope approach

Stable isotopes were used to examine the origin of organic matter in Icelandic Ascophyllum-based habitats, the role of different organic matters in filling intertidal food webs and the food preferences of the most abundant suspension feeders, grazers and predators. We selected three intertidal sites on the SW coast of Iceland where we sampled in early September 2004, organic matter sources (POM, SOM and most abundant primary producers, A. nodosum and F. vesciculosus) and the most abundant macrofauna species (barnacles, mussels, gastropods, sponge and crabs). Even though the primary production (Ascophyllum-based) was the same at the three study sites, the isotopic composition of common-among-sites organisms varied due to local differences in the origin of available POM and SOM and in food web structures.     

Effects of different extenders and centrifugation/washing on postthaw microscopic-oxidative stress parameters and fertilizing ability of Angora buck sperm

The main objective of the current study was to evaluate the effects of extender type and centrifugation/washing prior to cryopreservation on the postthaw sperm parameters, lipid peroxidation, and superoxide dismutase activity of Angora buck (Capra hircus ancryrensis) sperm. Ejaculates collected from three Angora bucks were used in this study. Two consecutive ejaculates from each buck were pooled and split into equal parts in four Falcon tubes. Two tubes were diluted at 37 °C and then centrifuged to remove semen plasma. After centrifugation, two sediment parts were diluted with a Tris-based extender and commercial Bioxcell extender, respectively. The remaining two parts, which were not centrifuged/washed, were diluted with the above-mentioned extenders, respectively. Diluted samples were cooled to 5 °C and frozen in 0.25-mL French straws to be stored in liquid nitrogen. Frozen straws were thawed individually at 37 °C for 20 sec in a water bath for evaluation. The semen part with centrifugation/washing in the Bioxcell extender (BC) demonstrated a higher rate of subjective motility (58.1 ± 3.0%) compared with that of groups with (TC) or without (T) centrifugation/washing in the Tris-based extender (P < 0.01). Angora buck sperm frozen with (BC) or without (B) centrifugation/washing in the Bioxcell extender demonstrated higher percentages of motility (60.6 ± 2.7% and 54.3 ± 4.8%, respectively) compared with that of groups T and TC. The postthaw progressive motility rate (22.3 ± 2.7%) was significantly greater for semen parts diluted in B compared with that of other groups. BC gave rise to a lower value of average path velocity (90.0 ± 5.2 μm/sec) compared with that of other groups (P < 0.01). For straight linear velocity and linearity index, the highest values (103.2 ± 4.7 μm/sec, 47.5 ± 1.6% and 94.8 ± 3.0 μm/sec, 44.8 ± 1.1%, respectively) were obtained from B and TC (P < 0.001). For sperm acrosome and total abnormalities, TC gave the highest values (11.2 ± 0.6% and 26.6 ± 1.5%, respectively, P < 0.01). In the group frozen in BC, the percentage of membrane integrity assessed by hypo-osmotic swelling test was higher (61.2 ± 2.2%) than that of the other groups (P < 0.001). With respect to fertility results based on 35-d pregnancy rates, BC gave a higher rate (76.5%) than that of TC (27.8%, P < 0.05). Malondialdehyde formation was found to be lower (1.64 ± 0.26 nmol/L) in BC than in the other groups after the freeze-thawing process (P < 0.001). In the semen part frozen in BC, superoxide dismutase activity was higher (0.18 ± 0.02 U/mg protein) compared with that of the other groups (P < 0.05). Further studies are required to obtain more precise results for the characterization of oxidative stress parameters and fertilizing ability in cryopreserved buck spermatozoa.