Effects of cadmium salt on phosphomonoesterases activity and fertilizing ability of fowl spermatozoa.

Daily administration of cadmium salt for 25 days (2.5 mg per Kg body weight) in the male domestic fowl caused the end of treatment period. An increased incidences of concentration. Fertility dropped to zero at the end of the treatment period. Activity of acid and alkaline phosphomonoesterases were also drastically reduced by the end of treatment period. An increased incidences of morphological abnormalities of spermatozoa were noticed in the treated birds. After 46 days cessation of the treatment, full recovery of the above measures was found. These alterations suggest the reversible type of effect of cadmium chloride on the spermatozoa of male domestic fowl.     

The influence of prepubertal partial sinistral ovariectomy on the subsequent reproductive function of domestic hens (Gallus domesticus )

Each of 20 White Leghorn hens of 13 to 14 weeks were subjected to partial sinistral ovariectomy and sham-operations. In half of the hens from each group, the percentage of egg production and clutch size were noted until 50 weeks of age. The growing pattern of normal ovarian follicles was also recorded at 26 weeks of age in a rest half ofthe hens in the two groups. The percentage of egg production and the mean and variance of clutch size did not differ significantly (P / 0.05) between the partially ovariectomized and sham-operated groups. The growing yellow follicles (>8 mm) in the rapidly developing phase in these two groups did not vary, although the smaller follicles (4 to 8 mm in diameter) remained significantly (P / 0.01) more in the shamoperated control group than in the partially ovariectomized group. This observation indicates that smaller follicles (4 to 8 mm) developed in the larger (>8 mm) follicles more efficiently in partially ovariectomized hens than in the sham-operated (control) hens. In a second experiment, one group of hens had all the yellow follicles (>8 mm) removed, while a second group of hens was left untreated. On the 3rd and 6th day post treatment, the hens were examined for the presence of ovarian follicles. No significant (P / 0.05) difference in the growing pattern of subsequent follicles (2 to 4 or 4 to 8 mm) was detected due to treatment. These data demonstrate that the mechanisms that regulate follicular growth and atresia are adjust to maintain normal ovulation following partial ovariectomy.     

Amphibolic role of the Krebs cycle in the insulin-stimulated protein synthesis.

It has been a generally held view that insulin does not significantly affect the incorporation of amino acids into liver protein. This interpretation was based on data obtained from studies using the branched chain amino acids, which are poorly metabolized by the hepatic tissue. The effect of insulin on 14CO2 formation and protein incorporation of several 1-14C-labeled or U-14C-labeled amino acids was studied in isolated rat hepatocytes and diaphragm pieces. It was shown that insulin enhanced 14CO2 formation and protein incorporation primarily of those carbons of amino acids which are metabolized through the mitochondrial Krebs cycle. Using aminooxyacetic acid (0.5 mM), a potent inhibitor of the transamination reaction, it was shown that there exists an "insulin-sensitive" pool of glutamate which is preferentially utilized for protein synthesis in the presence of insulin. The insulin effect on protein incorporation of 14C-labeled glutamate generated in the Krebs cycle was abolished in the presence of aminooxyacetic acid. We interpret these results to signify that mitochondrial transamination of alpha-ketoglutarate to glutamate is essential for insulin stimulation of 14C incorporation into hepatocyte protein.     

Studies on the cross stand hydrogen bonds in DNA double helices.

A systematic analysis has been carried out to examine all the stereochemically possible bifurcated hydrogen bonds including those of cross strand type between propeller twisted base pairs in DNA double helices by stereochemical considerations involving base pairs alone and by molecular mechanics studies on dimer and trimer duplexes. The results show that there are limited number of combinations of adjacent base pairs that would facilitate bifurcated cross-strand hydrogen bond (CSH). B-type helices concomitant with negative propeller twist seem to be more favored for the occurrence of CSH than canonical A-type helices because of slide in the latter. The results also demonstrate that helices with appropriate sequences may possess continuous run of these propeller twist driven cross strand hydrogen bonds indicating that they may in fact be considered as yet another general structural feature of DNA helices.     

Passive release of monoclonal antibodies from hybridoma cells

Evidence is presented for the passive release of monoclonal antibodies (MCAB) from hybridoma cells grown in either batch or continuous-flow culture. This release is promoted at room temperature. Passively released MCAB is indistinguishable from that released by actively growing cells, as judged by SDS-polyacrylamide gel electrophoresis. The significance of these observations in relation to the continuous culture of hybridoma cells is discussed.Maximum MCAB content of TB/C3 hybridoma cells is about 55pg per cell, any additional MCAB produced is secreted.Abbreviations MCAB monoclonal antibodies - PBS phosphate buffered saline - RT room temperature - SDS sodium dodecyl sulphate     

In vitro protein degradation measured by differential loss of labeled methionine and 3-methylhistidine: The effect of insulin

A new technique for studying the effect of insulin on protein degradation is reported. The method is based on measuring the parallel release of a reutilizable and a nonreutilizable amino acid from muscle protein. Animals are prelabeled in vivo with [Me-³H]methionine which labels both the nonreutilizable 3-methylhistidine and the reutilizable methionine of tissue protein. The data presented show that insulin has only a trivial effect on the loss of 3-methylhistidine from muscle protein, while it substantially diminishes the efflux of methionine. The analysis of muscle protein confirms the observation that insulin causes the reincorporation of methionine and has a minimum effect on the loss of 3-methylhistidine. This supports the view that the major inhibitory effect of insulin on gluconeogenesis is the diversion of the flow of amino acids away from the gluconeogenesis pathway back toward protein synthesis.     

Alterations in the responsiveness of diabetic fibroblasts to insulin

Fibroblastic cultures from the skin of nondiabetic and diabetic (db/db) mice have been used to investigate alterations in the biological responses of diabetic cells to insulin. Confluent cultures from the skin of both nondiabetic and diabetic animals possess specific receptors for insulin. Diabetic fibroblasts exhibit only 36% as much specific binding of insulin as nondiabetic fibroblasts, because of a decrease in the total number of binding sites, without a change in binding affinity. Insulin caused a time- and dose-dependent increase in the rate of 2-deoxy D-glucose (dGlc) uptake and in ornithine decarboxylase (ODC) activity of both nondiabetic and diabetic fibroblasts. In nondiabetic cells, half-maximal increase in dGlc uptake was obtained with 0.3 nM insulin, and a maximum increase of 120% was obtained with 4.1 nM insulin. In contrast, diabetic cultures required 0.8 nM insulin for a half-maximal increase in dGlc uptake, and maximum stimulation with 4.1 nM insulin was only 50% above control levels. With 4-fold higher insulin concentrations, ODC activity of diabetic cells was only 40% that of nondiabetic cells. In nondiabetic cells, down regulation of insulin receptors by insulin abolished the ability of insulin to stimulate dGlc uptake. These results demonstrate that cells cultured from diabetic animals, which possess a decreased number of insulin receptors, also exhibit decreased stimulation of deoxy D-glucose uptake and ornithin decarboxylase activity by insulin.     

Laser Doppler spectroscopy as applied to electrophoresis in protein solutions

The application of Laser Doppler spectroscopy (LDS) to the electrophoretic migration of macromolecules in solution by heterodyne light beating technique, previously developed by Ware and Flygare, has been improved by the design of a new microelectrophoresis cell and a high resolution in the frequency power spectrum. A 1024-channel correlator was used in combination with a software-controlled Fast Fourier transformation (FFT).This technique has been applied to single protein solution, bovine serum albumin (BSA), and to multicomponent systems, in particular to human blood serum. In comparison to normal free electrophoresis, LDS is more convenient and reveals more information in a much shorter period of time.     

Synthesis,characterization and biological aspects of novel five-coordinated dimeric-Cu(II) systems

The structural and spectroscopic properties of novel five-coordinated dimeric-Cu(II) system have been investigated. The biocidal activities of all eight compounds, ligands, cupric nitrate and standard drugs against six bacteria and three fungi were determined. The DNA interaction activity of complexes was studied using spectrophotometry and electrophoresis. The superoxide dismutase (SOD)-like activity of the complexes was compared with previously reported monomeric- and dimeric copper complexes. The results support the five-coordinated dimeric square pyramidal geometry for the quinolone-Cu(II) system.