Toxic metals, such as tributyltin (TBT), contribute substantially to anthropogenic pollution in many estuarine environments. Animals that live in those environments, particularly invertebrate filter feeders like tunicates, are likely to be exposed to substantial metal contamination. This study investigates the effects of TBT and other metals on the phenoloxidase activity of the estuarine tunica...

BACKGROUND Progress achieved in culture media formulations have resulted led to an improvement in maintaining the mammalian embryo in culture throughout the preimplantation and pre-attachment period. OBJECTIVE The objective of this study was to evaluate the effect of various concentrations of myo-inositol during in vitro fertilization of bovine oocytes on subsequent embryo development. MATE...

In this study, we report a total of 292 mouse embryos cultured on Vero cell monolayers and 77 embryos cultured in medium alone at different preimplantation stages examined individually for embryonic mRNA of beta-actin, interleukin-1beta (IL-1beta), interleukin-1 receptor antagonist (icIL-1ra) and interleukin-1 receptor type I (IL-1RtI) using reverse transcription and two-step polymerase chain r...

Polyembryony is a unique form of development in which many embryos are clonally produced from a single egg. Polyembryony is known to occur in many animals, but the underlying genetic mechanism responsible is unknown. In a parasitic wasp, Copidosoma floridanum, polyembryogenesis is initiated during the formation and division of the morula. In the present study, cDNA libraries were constructed fr...

OBJECTIVE It is not known whether progesterone, which plays a key role in establishing and maintaining pregnancy, acts directly on embryos or indirectly through the mother's reproductive tract. Since the physiological effects of progesterone are mediated by progesterone receptors (PR), the expression of PR during the preimplantation stages of pig embryos was determined. DESIGN AND METHODS Pre...

The present study examines the handling, activation, and micromanipulation of rat eggs in an attempt to produce live young using nuclear transfer (NT) of adult and genetically modified rat fetal cells. Mature rat eggs cultured in calcium-free medium showed reduced rates (24%) of chromosomal dispersion ("spontaneous activation" characteristic of this species) compared with eggs cultured in calci...

The overall aim of this work was to examine the expression profiles for fibroblast growth factor receptors (FGFRs) and describe their biological importance during bovine pre- and peri-implantation conceptus development. FGFR1 and FGFR2 mRNAs were detected at 1-, 2-, 8-cell, morula and blastocyst stages whereas FGFR3 and FGFR4 mRNAs were detected after the 8-cell stage but not earlier. The abund...