A comparative study on lipid peroxidation, activities of antioxidant enzymes and viability of cattle and buffalo bull spermatozoa during storage at refrigeration temperature.

A comparative study was conducted to monitor the activities of some antioxidant enzymes, lipid peroxidation and viability of cattle and buffalo bull spermatozoa during storage of semen at refrigeration temperature over a period of 72 h. Semen samples, collected from six cross bred cattle bulls (group I) and six Murrah buffalo bulls (group II), were diluted in egg-yolk-citrate and the spermatozoa were separated from seminal plasma by centrifugation at 4 degrees C in a refrigerated centrifuge. The malondialdehyde (MDA) production in group I increased from 1.17+/-0.29 at 0 h to 7.50+/-0.52 nmol/10(8)spermatozoa after 72 h of storage while in group II it increased from 1.99+/-0.26 to 8.70+/-0.10 nmol/10(8)spermatozoa in the same period. However, buffalo bull spermatozoa had a significantly higher (p<0.05) lipid peroxidation at 0 h as well as at 12, 24 and 48 h (p<0.01) periods. The activities of antioxidant enzymes viz. SOD, GPx and G6PD in both the groups showed a similar pattern of change i.e. the activities declined successively in spermatozoa and increased in the seminal plasma. However, the activities of these three enzymes remained significantly higher in the cattle bull spermatozoa than that in buffalo bull spermatozoa. Amount of MDA produced in spermatozoa of both the groups was negatively correlated while SOD, GPx and G6PD activities in spermatozoa were positively correlated to the motility and viability of spermatozoa. Sperm motility as well as viability was significantly less (p<0.05) in group II than that in group I. SOD, GPx and G6PD activities in spermatozoa of both the groups were negatively correlated to lipid peroxidation of spermatozoa cell membrane. The results showed that the less activities of antioxidant enzymes in buffalo bull spermatozoa was due to higher lipid peroxidation that indicated that they were more prone to oxidative stress as compared to cattle bull spermatozoa when stored at refrigeration temperature.

Status of lipid peroxidation, some antioxidant enzymes and erythrocytic fragility of crossbred cattle naturally infected with Theileria annulata.

Erythrocytic lipid peroxidation, activities of some antioxidant enzymes and osmotic fragility of red blood cells was studied in adult (>1 year) crossbred cattle naturally infected with Theileria annulata. Twenty clinically healthy animals (group I) and 15 clinical cases (group II) of tropical theileriosis were selected. Cattle suffering from theileriosis had significantly higher (p<0.01) erythrocytic lipid peroxidation and osmotic fragility. Activities of antioxidant enzymes, viz. glucose-6-phosphate dehydrogenase (G6PD) and glutamate peroxidase (GPx) were also significantly increased (p<0.01) in group II. However, superoxide dismutase and catalase did not show significant changes. The results indicated that infection with theileria led to increased oxidative stress to the animals, and even a significant rise in the activities of antioxidant enzymes. G6PD and GPx could not lower this oxidative stress. However, the increase in the activities of antioxidant enzymes pointed towards the body's defence mechanism against lipid peroxidation during oxidative stress in theileriosis.

Plasma hormonal and electrolyte alterations in cycling buffaloes (Bubalus bubalis) during hot summer months.

Plasma levels of progesterone, prolactin, luteinizing hormone, and electrolytes were monitored by radioimmunoassay in ten cycling buffaloes maintained at Punjab Agricultural University, Ludhiana during the hot summer months of June-July. The plasma progesterone concentration ranged from 0.28 +/- 0.04 to 3.09 +/- 0.03 ng/ml at various stages of the oestrous cycle. Prolactin values ranged from 319 +/- 23 to 371 +/- 25 ng/ml and LH levels from 0.95 +/- 0.05 to 1.35 +/- 0.08 ng/ml. Concentrations differed significantly (P less than or equal to 0.05) at various stages of the cycle. Levels of electrolytes, viz. Ca++, Na+ and K+, were well within the normal range. The high levels of prolactin, progesterone and LH during the hot summer were assessed in relation to poor reproductive efficiency in buffaloes.

Mechanism of adenylate cyclase activation by the rat lung cytoplasmic factors.

Epinephrine, histamine and prostaglandin E1 stimulated adenylate cyclase activity in lung membranes and their stimulation of the enzyme activity was completely blocked by propranolol, metiamide and indomethacin, respectively. A partially-purified activator from the adult rat lung also enhanced adenylate cyclase activity in membranes. However, stimulation of adenylate cyclase by the rat lung activator was not abolished by the above receptor antagonists. Further, epinephrine, NaF and Gpp(NH)p stimulated adenylate cyclase activity rather readily, whereas stimulation of the enzyme activity by the lung activator was evident after an initial lag phase of 10 min. Also, the lung activator produced additive activation of adenylate cyclase with epinephrine, NaF and Gpp(NH)p. These results indicate that the lung activator potentiates adenylate cyclase activity in membranes by a mechanism independent from those known for epinephrine, NaF and Gpp(NH)p. Incubation of lung membranes for 30 min at 40 degrees C resulted in a loss of adenylate cyclase activation by NaF and Gpp(NH)p. Addition of the released proteins to the heat-treated membranes did not restore the enzyme response to these agonists. However, heat treatment of lung membranes in the presence of 2-mercaptoethanol or dithiothreitol prevented the loss of adenylate cyclase response to NaF and Gpp(NH)p. N-ethylmaleimide abolished adenylate cyclase activation by epinephrine, NaF, Gpp(NH)p and the lung activator. These results indicate that the sulfhydryl groups are important for adenylate cyclase function in rat lung membranes.

Endocrine control of cytosolic factors stimulating adenylate cyclase in rat lung.

Endocrine control of cytoplasmic factors modulating adenylate cyclase activity in rat lung membranes was investigated. Hypophysectomy, adrenalectomy and thyroidectomy showed an adverse effect on the body and organ weights. Lung protein, glycogen and DNA contents were decreased in the endocrine ablated animals which were restored to the normal values on hormone treatment. Phosphodiesterase and phosphorylase activities were increased and decreased in adrenalectomized and thyroidectomized animals, respectively. The activities of these enzymes were restored to normal values on hormone treatment. Adrenalectomy and thyroidectomy affected ATPases differently. Basal adenylate cyclase activity in rat lung membranes was not affected by adrenalectomy and hormone treatment. However, the total enzyme activity was increased by both dexamethasone (DEX) and thyroxine (T4) treatments. The activation of the particulate adenylate cyclase by the cytoplasmic factors was markedly decreased in the lung from hypophysectomized, adrenalectomized and thyroidectomized rats. This decrease in the cytoplasmic activation of adenylate cyclase was restored to or above the control values on hormone treatment. Alteration in the activation of enzyme by cytoplasmic factors did not appear to be due to the change in the responsiveness of the enzyme. Glucocorticoids appeared to have a specific effect on the cytoplasmic factors modulating the enzyme.

Characterization and control of cytosolic binding proteins for 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in the rat lung.

The presence of a high-affinity, low-capacity 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) binding complex was demonstrated in cytosol from rat lung. When analyzed by sucrose density gradient centrifugation, the 3H-TCDD binding complex sedimented at 8-9 S and 6.5 S in low and high ionic media, respectively. The apparent dissociation constant (Kd) of the 3H-TCDD binding complex was determined to be 2.9 nM and the number of binding sites (Bmax) was approximately equal to 69 fmol/mg of cytosolic protein. The entity was sensitive to heat and to proteases but not to DNAse or RNAse, indicating that it was a protein. An excess of unlabeled TCDD, benzo[a]pyrene, 3-methylcholanthrene, 7,12-dimethylbenzo[a]anthracene and 9-hydroxy ellipticine all competed with 3H-TCDD for binding. A single injection of either benzo[a]pyrene (20 mg/kg body weight) or 9-hydroxy ellipticine (20 mg/kg body weight) had different effects on the concentrations of 3H-TCDD binding proteins in the lung but none of the chemicals had a significant effect on the synthesis of surfactant as assayed by total phospholipid content, 72 h after the injection.

Effects of dexamethasone administration to pregnant rats on adenylate cyclase and cyclic AMP phosphodiesterase activities in the maternal and fetal lungs.

Adenylate cyclase and cyclic AMP phosphodiesterase activities were examined in the maternal and fetal lungs before and after delivery from the saline- and dexamethasone-treated pregnant rats. Basal adenylate cyclase activity in the maternal lungs of control animals did not change after parturition whereas the enzyme activity in fetal lungs increased 2.5-fold after birth. Dexamethasone treatment reduced adenylate cyclase activity in the maternal lungs before and after parturition while the enzyme activity in fetal lungs was increased. The ability of the cytoplasmic factors to activate adenylate cyclase in maternal lungs decreased after parturition. Dexamethasone treatment of the pregnant rat lowered the cytoplasmic activation of the maternal enzyme before and after parturition, but the percent activation of the enzyme in both the maternal and fetal lungs was not affected. The decrease in activator activity of the maternal lungs after parturition was not apparently due to the reduced sensitivity of adenylate cyclase to the same level of the activator protein. However, it would appear that both adenylate cyclase and its activator protein have undergone some maturational changes during lung development. Adrenalectomy of rats did not alter the basal adenylate cyclase activity in lung membranes but reduced the cytoplasmic activation of the enzyme. Unlike pregnant rats, dexamethasone treatment of adrenalectomized rats restored the cytoplasmic activation of adenylate cyclase not only to the control value, but potentiated it even higher than the control without affecting the basal adenylate cyclase activity. Cyclic AMP phosphodiesterase activity in both the maternal and fetal lungs was not influenced by parturition.(ABSTRACT TRUNCATED AT 250 WORDS)

Partial purification and properties of the cytoplasmic factors modulating adenylate cyclase activity in rat lung plasma membranes.

The adult rat lung supernatant contains some factors which markedly enhance adenylate cyclase activity in membranes (Nijjar, M.S. (1979) Biochim. Biophys. Acta 584, 43-50). These factors were separated into two less active components (peaks 1 and 2) by DEAE-cellulose chromatography. However, their recombination restored the full activation of adenylate cyclase. Further purification and characterization of these factors revealed that the activator in peak 1 contained two proteins of low (14 500) and high (65 000) molecular weight whereas the activator in peak 2 contained only one protein of 65 000. The kinetics of adenylate cyclase activation revealed that both the Km and V values were affected. The data also demonstrate that calmodulin was not involved in the cytoplasmic activation of adenylate cyclase in rat lungs.

Toxic substances produced by Fusarium V: occurrence of zearalenone, diacetoxyscirpenol, and T-2 toxin in moldy corn infected with Fusarium moniliforme Sheld.

Sweet corn infected with Fusarium moniliforme Sheld. (CMI-IMI 204057) while growing in the fields was shown to contain zearalenone, diacetoxyscirpenol, and T-2 toxin. Assays by spectral, chemical, and biological methods established the presence of these substances, with zearalenone being the most abundant. In vitro cultures of the fungus also produced the three toxins.

The occurrence of 12, 13-epoxytrichothecenes in seeds of safflower infected with Fusarium oxysporum f. sp. carthami.

From the seeds of safflower (Carthamus tinctorius Linn.), infected with Fusarium oxysporum f. sp. carthami, 3 toxic compounds have been isolated in quantities sufficient to cause mycotoxicosis on prolonged ingestion. 2 of these have been identified as diacetoxyscirpenol and T-2 toxin, while the third one has also been partially characterized as a 12, 13-epoxytrichothecene. Additionally, the incidence of secondary fusarial infection of healthy seeds due to contamination with the infected ones has been reported for the first time.