Search

Maintenance of female reproductive competence depends on the actions of several hormones and signaling factors. Recent reports suggest roles for bone morphogenetic proteins (BMPs) in early stages of folliculogenesis. A role for the type I BMP receptor BmprIB as a regulator of ovulation rates in sheep has been described recently, but little is known about the roles of BMP signaling pathways in other aspects of reproductive function. We report here that BMPRIB is essential for multiple aspects of female fertility. Mice deficient in BmprIB exhibit irregular estrous cycles and an impaired pseudopregnancy response. BmprIB mutants produce oocytes that can be fertilized in vitro, but defects in cumulus expansion prevent fertilization in vivo. This defect is associated with decreased levels of aromatase production in granulosa cells. Unexpectedly, levels of mRNA for cyclooxygenase 2, an enzyme required for cumulus expansion, are increased. BmprIB mutants also exhibit a failure in endometrial gland formation. The expression of BmprIB in uterine linings suggests that these defects are a direct consequence of loss of BMP signaling in this tissue. In summary, these studies demonstrate the importance of BMP signaling pathways for estrus cyclicity, estradiol biosynthesis, and cumulus cell expansion in vivo and reveal sites of action for BMP signaling pathways in reproductive tissues.

Studies of the interaction of polarized light or particles (including electrons, e-, or positrons, e+) with asymmetric forms of matter has been of interest to scientists since the discovery of chirality and the subsequent development of particle physics. Researchers have been interested in e+ interactions with chiral molecules for decades, but with mixed and indecisive results. After reviewing the field, we speculated that the e+ or positronium (Ps) might interact differently with chiral pairs of large single crystals, i.e., the left-handed or right-handed asymmetric forms of the crystals -- and subsequently observed significant differences in "free positron" annihilation and intensities in the evaluation of left-handed or right-handed quartz single crystals. This result may be understood to be a "particle stereorecognition" phenomenon. To extend this line of inquiry we crystallized mm scale L- or D-alanine crystals and performed positron annihilation lifetime spectroscopy measurements using a 22Na positron source. Alanine crystals were obtained via slow evaporation of water in a Dewar, or from water/acetone solvent in a temperature-controlled environment. These methods resulted in small (≈ 0:5 cm/side) or large (≥ 1:0 cm/side) crystals, respectively. While some intensity (I2) results from left-handed and right-handed crystals varied in positron annihilation lifetime spectroscopy analysis, the errors associated with the measurements do not indicate a stereorecognition of alanine via positron interactions. [ABSTRACT FROM AUTHOR]