[Comparison of the effects of Myo-inositol alone or in combination with MEM vitamins on embryo development in Sanjabi Sheep]

The objective of this study was to evaluate the effects of myo-inositol alone or in combination with MEM vitamins on embryo development in sanjabi sheep. Sheep Cumulus Oocytes Complexes [COCs] were matured in vitro at 39 °C, in humidified 5% CO2 atmosphere for 22-24 h. There were three treatments, culture in synthetic oviductal fluid medium [treatment I], culture in synthetic oviductal fluid medium supplemented with1 x MEM vitamins [treatment II], culture in synthetic oviductal fluid medium supplemented with myo-inositol [treatment III], COCs were then fertilized and cultured in vitro for and days when the ratios of in vitro embryo development of the hatched blastocysts were assessed and compared with the control group. The presence of myo-inpsitol significantly improved overall morula rates [34.39%] than that of control group [24.18%], but there was no difference between myo-inositol and 1 x MEM vitamins in the percentage of embryos successfully developing to the morula stage [p<0.05]. The addition of myo-inositol improved the mean blastocyst formation compared to the oocytes matured in medium containing no MEM [control] or 1 x MEM vitamins [32.63, 13.96 and 21.06% respectively]. However, the mean percentage of cleavage rate was not substantialy different between treatments. These results suggest that adding myo-inositol to SOF medium be more beneficial for subsequent sheep embryonic development

Regulation of MAL1+ gene expression encoding maltase in Schizosaccharomyces pombe by added inositol.

In this study, the effects of inositol addition on maltase activity and expression of MAL1+ gene encoding maltase in Schizosaccharomyces pombe were investigated. The maximum specific maltase activity was observed, when the concentration of inositol reached 6.0 microg/ml in the synthetic medium containing 2.0% glucose. At 1.0 microg/ml inositol concentration, the maltase activity continuously decreased, as initial glucose concentration was higher than 0.1%. mRNA encoding maltase and phosphatidylinositol (PI) content were higher in the cells grown in the synthetic medium with 6.0 microg/ml of inositol and 2.0% glucose than those with 1.0 microg/ml of inositol. These results demonstrated that higher inositol concentration in the synthetic medium could derepress MAL1+ gene expression in S. pombe and PI might be involved in derepression of MAL1+ gene expression in S. pombe probably by PI-type signalling pathway.

Effect of myoinositol on sporangiospore-yeast transformation of Mucor circinelloides Tieghem cultivated in synthetic broth.

Mucor species exhibit fungal dimorphism in controlled environments. In this work, we examined the effect of myoinositol supplementation on the growth and morphology of Mucor circinelloides. Using sporangiospores as inoculums, diverse morphologies were induced in synthetic broth incubated at pH 4.5, temp. 20 degrees C, ambient. The morphologies included thallic suptypes (holoblastic-, holothallic-, enterothallic conidia as well as vesicular conidial headgroups), which were determinate in growth, and proliferating yeast forms. Analysis of variance, p<0.05, showed that time had significant impact on growth. A separation of means, l.s.d. 14.34, p<0.05, indicated that myoinositol supplementation at 500 microM supported the least growth, but 2.0-3.0 mM levels had the higher values, and this was followed by the control, 300 microM, 1.0, 2.0, 5.0 mM supplementations. Although the predominant morphology, that is, terminal budding yeast cells was not quantitated, observation showed that it was more preponderant, had optimal size and cell shape became more regular at 2.0 mM myoinositol supplementation.

Inter-conversion of free sugars and accumulation of galactomannan in response to supplied metabolic mediators during pod filling in guar.

Detached inflorescences of guar (Cyamopsis tetragonoloba), each bearing 4 uniformly-developing pods at 42 days post anthesis (DPA), were cultured for 6 days in complete liquid medium manipulated with a fixed concentration of mannose and varying concentration of myo-inositol. Such inflorescences, but with 2 pods, were also maintained in the solutions of (i) glucose(U-14C) containing myo-inositol or phytohormones, and (ii) mannose(U-14C) containing galactose for 36 hr. Effect of such exogenously supplied metabolic mediators on interconversion of free sugars in pod wall, endosperm and cotyledons and galactomannan accumulation in endosperm was studied. Myo-inositol decreased, over control, the relative proportion of invert sugars in pod wall, endosperm and cotyledons and at lower concentration (27.75 mM) it decreased the level of free sugars in pod wall and galactomannan in endosperm. In all pod tissues, 14C from both glucose and mannose got incorporated into myo-inositol as well as various sugars and maximum incorporation occurred in sucrose. High concentration of total free sugars and their 14C activity in pod wall indicated that this pod tissue was a potent accumulator of free sugars. With myoinositol, the relative proportion of 14C from glucose into raffinose sugars of pod wall and endosperm increased with a simultaneous decrease in this incorporation into galactomannan of the latter. Accompanying this, relative proportion of 14C into hexoses and myo-inositol decreased in pod tissues. Galactose increased 14C incorporation from mannose into total free sugars, sucrose and galactomannan with a concomitant decline in the labelling of hexoses. IAA and ABA enhanced 14C incorporation from glucose into total free sugars and this enhancement was much higher with IAA than ABA. The latter inhibited 14C incorporation into galactomannan. Based on these results, it was suggested that myo-inositol at lower concentration was inadequate to mediate the metabolism of sugars and, thereby, galactomannan synthesis. Galactose and mannose exhibited a mutual beneficial effect on their transportation to pods. Phytohormones stimulated the accumulation of sucrose in pod wall for its obligatory unloading into the seed.

Domoic acid induces neurotoxicity and ip3 mobilization in cultured cells of embryonic chick retina

Domoic acid (DOM), 1 to 50 µM, a glutamate agonist responsible for several neurological effects such as loss of memory and confusion, induced the death of cultured neurons of chick embryonic retina, in a concentration- and Ca2+ -dependent manner. This effect was blocked by 100 µM CNQX, a competitive antagonist of the non-NMDA receptor, but not by 10 µM MK-801, a non-competitive antagonist of the NMDA receptor. DOM also induced inositol triphosphate (ip3) accumulation 4 to 7 times above basal levels. This effect was also dependent on external Ca2+ and was entirely blocked by 100 µM CNQX, but not by 10 µM MK-801. These results suggest that DOM interaction with non-NMDA glutamate receptors mediates signal transduction with ip3 accumulation and cell death

Kinetic studies on the membrane form of intestinal alkaline phosphatase

We have purified different membrane and soluble forms of alkaline phosphatase from human placenta and bovine intestine. The enzymes will be used as markers in immunoconjugates and/or as model for membrane enzyme studies. The membrane formof alkaline phosphatase extracted from bovine intestine was purified on Q-Sepharose and on L-histidyldiazobenzylphosphonic acid-agarose columns to remove phosphodiesterase activity. The purified enzyme had a molecular mass of 61 kDa, Km of 1208 µM, and Vmax 240 µmol pNP/min when assayed in 1 M diethanolamine, 0.5 mM MgCl2 buffer, pH 9.8, containing 10 to 2250 µM of pNPP at 37§C. In the present investigation we studied the effect of salts and inositol derivatives on this enzyme activity, which was found to depend on 0.5 mM Mg2+, and to be fully inhibited by 1.2 mM Hg2+. Vanadate (0.5 mM) and Zn2+ (0.5 mM) reduced the Km value by 43 percent and 84 percent, respectively. Inositol (2 mM) and inositol-2-monophosphate (2 mM) reduced the activity by 23 percent and 17 percent. Inositol-1-monophosphate (0.5 mM) and cyclic-inositol-(1:2)-monophosphate (0.5 mM) enhanced their Km value by at least 30 percent compared to p-nitrophenylphosphate