Mammalian metaphase II (mII) exit and embryogenesis are induced at fertilisation by a signal thought to come from the sperm protein, phospholipase C-zeta (PLCZ1). Meiotic progression can also be triggered without sperm, as in parthenogenesis, although the classic mouse in vivo parthenogenetic model, LT/Sv, fails in meiosis I owing to an unknown molecular etiology. Here, we dissect PLCZ1 specifi...

Oviductal microenvironment generally provides better conditions for early embryo development than the conventional in vitro system. In an attempt to simulate the oviduct conditions or the main potentially influencing factors, the effect was studied of a bovine oviductal fluid (bOF) treatment applied prior to IVF on (i) IVF parameters, (ii) cleavage rate, (iii) blastocyst yield and (iv) blastocy...

The objective of this study was to elucidate the toxicity of widely used penetrating cryoprotective agents (CPAs) to mammalian oocytes. To this end, mouse metaphase II (M II) oocytes were exposed to 1.5 M solutions of dimethylsulfoxide (DMSO), ethylene glycol (EG), or propanediol (PROH) prepared in phosphate buffered saline (PBS) containing 10% fetal bovine serum. To address the time- and tempe...

INTRODUCTION The suggestion has been made that the response of an egg to the action of a spermatozoon or parthenogenetic agent may be similar to that of a nerve to stimulation (Lillie, 1909). If this were so, it might be expected that activation, whether by a parthenogenetic agent or by a spermatozoon, would cause an increase in the permeability of the egg surface; although this increase in per...

An outstanding problem for evolutionary biology is the maintenance of anisogamous sex in the face of the ostensible twofold reproductive advantage accruing to parthenogenetic females that do not produce male offspring (Williams, 1975; Maynard Smith, 1978; Bell, 1982). Conventional solutions are sought in terms of cryptic advantages to sex involving variable environments, genetic load, and DNA d...

PURPOSE to evaluate the meiotic spindle and the chromosome distribution of in vitro mature oocytes from stimulated cycles of infertile women with endometriosis, and with male and/or tubal infertility factors (Control Group), comparing the rates of in vitro maturation (IVM) between the two groups evaluated. METHODS fourteen patients with endometriosis and eight with male and/or tubal infertili...

Six new species of Fergusobia, from large multilocular shoot bud galls on two species of Angophora and four species of Eucalyptus from both subgenera Eucalyptus and Symphyomyrtus, are described. Fergusobia cosmophyllae Davies n. sp. is characterized by the combination of a C-shaped parthenogenetic female with a short arcuate conoid tail, a broad (small a ratio) arcuate infective female with an ...