523 research outputs found

    Photosynthetic responses of three common mosses from continental Antarctica

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    Predicting the effects of climate change on Antarctic terrestrial vegetation requires a better knowledge of the ecophysiology of common moss species. In this paper we provide a comprehensive matrix for photosynthesis and major environmental parameters for three dominant Antarctic moss species (Bryum subrotundifolium, B. pseudotriquetrum and Ceratodon purpureus). Using locations in southern Victoria Land, (Granite Harbour, 77°S) and northern Victoria Land (Cape Hallett, 72°S) we determined the responses of net photosynthesis and dark respiration to thallus water content, thallus temperature, photosynthetic photon flux densities and CO2 concentration over several summer seasons. The studies also included microclimate recordings at all sites where the research was carried out in field laboratories. Plant temperature was influenced predominantly by the water regime at the site with dry mosses being warmer. Optimal temperatures for net photosynthesis were 13.7°C, 12.0°C and 6.6°C for B. subrotundifolium, B. pseudotriquetrum and C. purpureus, respectively and fall within the known range for Antarctic mosses. Maximal net photosynthesis at 10°C ranked as B. subrotundifolium > B. pseudotriquetrum > C. purpureus. Net photosynthesis was strongly depressed at subzero temperatures but was substantial at 0°C. Net photosynthesis of the mosses was not saturated by light at optimal water content and thallus temperature. Response of net photosynthesis to increase in water content was as expected for mosses although B. subrotundifolium showed a large depression (60%) at the highest hydrations. Net photosynthesis of both B. subrotundifolium and B. pseudotriquetrum showed a large response to increase in CO2 concentration and this rose with increase in temperature; saturation was not reached for B. pseudotriquetrum at 20°C. There was a high level of variability for species at the same sites in different years and between different locations. This was substantial enough to make prediction of the effects of climate change very difficult at the moment

    Effects of levamisole on hyaluronidase activity and sperm characteristics in rams

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    The aim of this study was to determine the effects of levamisole on sperm characteristics and hyaluronidase activity of blood serum and semen. For this purpose, 12 Akkaraman rams (2–3 years old) were used. Levamisole hydrochloride was administered orally at a dose of 7.5 mg/kg body weights once daily for 2 days. Serum and semen samples were collected from the rams at posttreatment 1, 2, 4, 24, 48, 72, 96, 120, 144, 216, 288 and 384 h and examined for sperm characteristics and hyaluronidase activity. The results showed that the use of levamisole caused significant (P < 0:01) increase in serum hyaluronidase activity at all times except the 72 h, and in semen hyaluronidase activity at 1, 2, 4, 24, 72, 96 and 120 h compared to the control group. In addition, the levamisole caused significant (P < 0:05) decreases in semen volume, sperm motility, concentration and total sperm number at all times. There was no correlation between semen hyaluronidase activity and the sperm characteristics. In conclusion, levamisole did not have any deleterious effect on hyaluronidase enzyme. However, the use of this drug in rams during the breeding season is harmful due to the decrease of sperm characteristics

    The protective effects of melatonin and vitamin E on antioxidant enzyme activities and epididymal sperm characteristics of homocysteine treated male rats

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    The aims of this study were to investigate the effects of homocysteine (Hcy) on epididymal sperm characteristics, plasma testosterone level and biochemical changes related to oxidative stress and to examine the effects of melatonin (Mlt) or Vitamin E (VE) administration on these parameters in Hcy-treated male rats. In this study, 32 adult male albino rats of Wistar strain were used. The rats were randomly divided into four groups. The first group of rats received only Hcy (0.71 mg/kg/day) intraperitonially (ip) for 6 weeks. The second group of rats was given Hcy along with simultaneous administration of Mlt (1 mg/kg/day) subcutaneously. The third group of rats received Hcy along with simultaneous administration of VE (125 mg/kg/day, ip). The fourth group of rats served as control during 6 weeks and was daily given 0.1mL of physiological saline (NaCl, 0.9%) ip. While the plasma malondialdehyde level significantly (p < 0.05) increased, the plasma superoxide dismutase, glutathione peroxidase and catalase activities significantly (p < 0.05) decreased in Hcy-treated rats when compared to control rats. Furthermore, the epididymal sperm concentration, the percentage of progressive sperm motility and plasma testosterone level were significantly (p < 0.05) lower in Hcy-treated rats than those of the control rats. The simultaneous administration of Mlt or VE to Hcy-treated animals impeded the decrease in the plasma antioxidant enzyme activities, testosterone level, the epididymal sperm concentration and motility. In conclusion, this study indicates that chronic administration of Hcy has the harmful effect on the epididymal sperm characteristics of male rats. The administration of Mlt or VE can prevent adverse effects of Hcy on the plasma antioxidant enzyme activities, testosterone level, epididymal sperm count and motility in male rats

    Effect of clitoral massage on levels of estradiol, testosterone, dehydroepiandrosterone sulphate and pregnancy rate in cows

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    This study was conducted to investigate the effect of clitoral massage on levels of estradiol (E2), testosterone (T), dehydroepiandrosterone sulphate (DHEA-S) and pregnancy rate in cows. For this purpose, 38 Holstein cows ranging from 3-6 years old were used. The cows were divided into two groups, as control (n=19) and application (n=19). The degree of intensity of oestrus expression was scored on a scale of 0 to 5 by considering knowledge of anamnesis, findings of rectal palpation and inspection as a criteria. All animals of both groups were artificially inseminated by recto-vaginal method with frozen-thawed bull semen. Clitoral massage was applied to the cows in the application group for 15-30 sec. after artificial insemination. Blood samples were then taken from jugular vein and centrifuged at 5000 rpm for 5 m., and serum samples were stored deep-frozen at -20 oC. Levels of E2, T and DHEA-S were determined by RIA method. All animals were examined by rectal palpation of the uterus for pregnancy on day 75 after insemination. Clitoral massage application had no significant effect on the levels of E2, T, DHEA-S and pregnancy rate in cows. There was a significant difference (P<0.05) in the degree of the intensity of oestrus between control and application groups. A significant negative correlation (P<0.01, r = -0.93) was found between levels of E2 and T

    Assessment of Austrian contribution toward EU 2020 target sharing: Responding to the energy and climate package of the European Commission

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    The overarching implications of the EU 2020 targets for Austria call for a fundamental restructuring of the Austrian energy sector towards increased energy efficiency. Two guiding principles for this restructuring are required in order to be compatible with the targets for greenhouse gas emissions and renewables (RES) expected for Austria: final energy consumption needs to be stabilised at the levels of 2005; renewable energy sources need to be expanded at least by 40 percent. For the final negotiations on phase 3 of the EU Emissions Trading System we propose contributions on three issues: 1. operational procedures for dealing with carbon leakage and competitiveness in all sectors that provide criteria for allocating free allowances: 2. empowering the carbon market by extending the task of the emissions allowances issuing carbon authority to control the liquidity of the carbon market in view of stabilising the carbon price; 3. designing the auctioning mechanism by considering timing and auctioning as a strategic instrument for enhancing the carbon market and considering unified auc-tioning with revenues split among EU countries. Similarly we suggest for the final negotiations on the RES Directive improvements that overcome discrepancies between national RES targets and available resources for implementation. This requires in particular improved cooperation between EU countries for a better mapping of targets and potentials

    Lycopene and ellagic acid prevent testicular apoptosis induced by cisplatin

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    The aim of this studywasto investigate the possible protective effects of lycopene (LC) and ellagic acid (EA) on cisplatin (CP)-induced testicular apoptosis in male rats. The control group was treated with placebo; LC, EA and CP groups were given alone LC, EA and CP, respectively; the CP + LC group was treated with a combination of CP and LC; and the CP + EAgroup was treated with a combination of CP and EA. Although CP significantly increased the number of Bax-positive (apoptotic) cells it had no effect on the number of Bcl- 2-positive (antiapoptotic) cells compared with the control group. Administration of CP caused significant increase in lipid peroxidation and nonsignificant decrease in superoxide dismutase (SOD) activity along with some histopathological lesions in testicular tissue. However, combined treatments of LC or EA in addition to CP tended to prevent the CP-induced testicular apoptosis, histopathological lesions and lipid peroxidation

    Erkek köpeklerde intratestiküler gliserol ve etanol uygulamalarının kısırlaştırma üzerine etkilerinin karşılaştırılması (Comporation of the Effects of Intratesticular Glycerol and Ethanol Injections on Sterilization of Male Dogs)

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    This study was conducted to investigate the effects of intratesticular glycerol and ethanol injection on sterilization. Twelve mature male dogs were used. They were allocated randomly to two equal groups called glycerol and ethanol and one ml glycerol (70%) and ethanol (95%) was injected intratesticularly. The animals were observed during two months. The blood and sperm samples obtained once a week in all groups were examined regarding to serum testosterone level and spermatozoon concentration and motility rate. There was a fistula formation and scrotal wounds resulting from orchitis in all glycerol and two ethanol group dogs after the 5th day of injection. The fistular openings closed spontaneously in all cases in due course. After the 2nd month, testicular atrophy was seen to occur. It was determined the presence of marked decreases (p<0.01) in both groups spermatozoon concentration and motility as well as in the level of serum testosterone two weeks after drug injection. The histopathologic examination conducted after the 2nd month revealed degeneration, necrosis and diffuse connective tissue proliferation in the seminiferus contortus tubulus of both groups. It has been concluded that glycerol and ethanol can be effective for sterilization in male dogs

    Antiperoxidative and anti-apoptotic effects of lycopene and ellagic acid on cyclophosphamide-induced testicular lipid peroxidation and apoptosis

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    The present study was conducted to investigate the possible protective effects of lycopene (LC) and ellagic acid (EA) on cyclophosphamide (CP)-induced testicular and spermatozoal toxicity associated with the oxidative stress and apoptosis in male rats. Forty-eight healthy adult male Sprague-Dawley rats were divided into six groups of eight rats each. The control group was treated with placebo; the LC, EA and CP groups were given LC (10 mg kg−1), EA (2 mg kg−1) and CP (15 mg kg−1), respectively, alone; the CP+LC group was treated with a combination of CP (15 mg kg−1) and LC (10 mg kg−1); and the CP+EA group was treated with a combination of CP (15 mg kg−1) and EA (2 mg kg−1). All treatments were maintained for 8 weeks. At the end of the treatment period, bodyweight and the weight of the reproductive organs, sperm concentration and motility, testicular tissue lipid peroxidation, anti-oxidant enzyme activity and apoptosis (i.e. Bax and Bcl-2 proteins) were determined. Administration of CP resulted in significant decreases in epididymal sperm concentration and motility and significant increases in malondialdehyde levels. Although CP significantly increased the number of Bax-positive (apoptotic) cells, it had no effect on the number of Bcl-2-positive (anti-apoptotic) cells compared with the control group. However, combined treatment of rats with LC or EA in addition to CP prevented the development of CP-induced lipid peroxidation and sperm and testicular damage. In conclusion, CP-induced lipid peroxidation leads to structural and functional damage, as well as apoptosis, in spermatogenic cells of rats. Both LC and EA protect against the development of these detrimental effects

    Attenuating effect of lycopene and ellagic acid on 2,3,7,8-tetrachlorodibenzo-p-dioxin-induced spermiotoxicity and testicular apoptosis

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    This study was conducted to investigate the prophylactic effects of lycopene (LC) and ellagic acid (EA) on 2,3,7,8- tetrachlorodibenzo-p-dioxin (TCDD)-induced testicular and spermatozoal toxicity. These toxicological changes are associated with the oxidative stress and apoptosis in male rats. Forty-eight male rats were allocated to one of six groups of 8 rats each: control, LC, EA, TCDD, TCDD+LC, and TCDD+EA. The control group was treated with 0.5 mL/ rat slightly alkaline solution+0.5 mL/rat corn oil every other day. The LC group was treated with 0.5 mL/rat slightly alkaline solution+0.5 mL/rat corn oil containing 10 mg/kg of LC every other day. The EA group received 0.5 mL/rat corn oil+0.5 mL/rat slightly alkaline solution containing 2 mg/kg of EA every other day. The TCDD group received 0.5 mL/rat corn oil containing 100 ng/kg/day of TCDD+0.5 mL/rat slightly alkaline solution. The TCDD+LC group was treated with 0.5 mL/rat TCDD+0.5 mL/rat LC. The TCDD+EA group was treated with 0.5 mL/rat TCDD+0.5 mL/rat EA. All treatments were made by gavage, and the experimental period was maintained during 8 weeks. Sperm motility, concentration, and abnormal sperm rate in epididymal tissue, testicular tissue lipid peroxidation (LPO), antioxidant enzyme activity, histopathological changes, and apoptosis (i.e., Bax and Bcl-2 proteins) were determined. TCDD exposure resulted in significant decreases in sperm motility, concentration, testicular superoxide dismutase activity, germinal cell-layer thickness, Johnsen’s testicular score, and significant increases in abnormal sperm rate, testicular malondialdehyde, glutathione levels, Bax-positive staining, and Bax-positive apoptotic cell score, along with some testicular histopathological lesions. TCDD treatment did not affect significantly catalase activity. However, combined treatment with LC or EA, in addition to TCDD, prevented the development of TCDD-induced damages in sperm quality, testicular histology, and LPO. Improvements in testicular apoptosis after the administration of LC and EA to TCDD-treated rats were minimal, but not statistically significant. TCDD-induced lipid peroxidation leads to functional and structural damages, as well as apoptosis, in spermatogenic cells of rats. Both LC and EA protected against the development of these effect
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