Role of Melatonin as a Survival Factor for In vitro Development of Sheep Preantral Follicles

Background: Melatonin, a powerful free radical scavenger and broad-spectrum antioxidant may directly affect ovarian function by regulating folliculogenesis, maintenance of follicular integrity, oocyte quality and maturation capacity. Therefore, we aimed to study effects of melatonin and its interaction with growth factors in sheep preantral follicles. Methods: The influence of different concentrations of Melatonin (5-500 pM) on in vitro culture of preantral follicles (PFs’) isolated from sheep ovaries was studied. Experiments I and II were conducted to standardize the optimum concentration of Melatonin that supports better development of preantral follicles. Experiment III was conducted with the optimum level of Melatonin derived in the Experiments I and II to evaluate the effect of melatonin at 100pM in combination with various growth factors. Result: Overall follicular development was found to be the best in the PFs’ cultured in medium supplemented with 100pM of Melatonin. Melatonin supplementation showed positive effects on the preantral follicular development in combination with different growth factors. </jats:p

Leptin Supplementation Stimulates Synergism with Growth Factors and Hormones to Express Its Receptor in Cultured Preantral Follicles of Sheep

Background: Leptin receptor is a transmembrane receptor that regulates reproduction at molecular level.Since for action of any hormone on target cell and to have local action on any tissue, expression of its own receptor is necessary and also it is not known whether such improvement in ovarian follicular development by Leptin is mediated through presence of its homologous receptors in the sheep ovaries. Therefore this study aimed on expression of Leptin receptor mRNA in cultured ovarian follicles of sheep by RT PCR.Methods: Leptin receptor mRNA expression in sheep was studied using qRT-PCR from: (i) In vivo grown preantral, early antral, antral, large antral follicles and cumulus oocyte complexes obtained from large antral follicles subjected to 24h of in vitro maturation and (ii) PFs’ exposed to three different culture media for 3min, two, four or six days and subsequently matured in vitro for 24h. Result: Leptin receptor was observed at all stages ovarian follicles in both cumulus cells and oocytes. Leptin supplementation along with other growth factors and hormones stimulated the expression of its receptor mRNA which is parallel to in vivo stages which could suggest synergistic action of growth factors and hormones with Leptin. </jats:p

Measurements of Atmospheric Parameters During Indian Space Research Organization Geosphere Biosphere Programme Land Campaign II at a Typical Location in the Ganga Basin: 1. Physical and Optical Properties

This paper attempts to characterize the physical and optical properties of the aerosols along with relevant meteorological parameters at a typical location in the Ganga basin. The emphasis is on delineating the prolonged foggy/hazy conditions, a phenomenon believed to be of relatively recent origin, faced by millions of people during the winter months of December and January. Collocated measurements of a number of aerosol and atmospheric parameters were made using ground-based instruments as part of an intense field campaign launched under the Indian Space Research Organization Geosphere Biosphere Programme in December 2004. The meteorological conditions suggest limited mixing due to shallow boundary layer thickness and essentially calm wind conditions. Monthly mean aerosol optical depth was high (0.77 ± 0.3 at 0.5 μm wavelength) and showed high spectral variation (first-order Angström exponent for all wavelengths, α = 1.24 ± 0.24). The second-order Ångström exponent α' derived for 0.34, 0.5, and 1.02 μm wavelengths showed much higher curvature in the aerosol optical depth spectrum on the hazy/foggy days (0.93 ± 0.36) as compared to that during the clear days (0.59 ± 0.3). Single-scattering albedo (0.87-0.97) showed strong spectral variation. Aerosol mass concentration was high with monthly average 125.9 ± 47.1 μg m-3. Fine mode particles (<1 μm) contributed ∼75% to the total mass of aerosols. Similarly, aerosol number concentration was found to vary in the range 1.5-2 × 103cm-3, with fine mode particles contributing to ∼99.6%. The hazy/foggy conditions typically prevailed when higher daytime relative humidity, lower maximum temperature, and higher fine/accumulation mode particles were observed. The companion paper suggests that the rise in aerosol mass/number concentration could be attributed to the aqueous-phase heterogeneous reactions mediated by anthropogenic pollutants and the associated reduction in boundary layer thickness and suppressed mixing. Copyright 2006 by the American Geophysical Union