Polychlorinated biphenyls (PCBs) are one of the most persistent and widespread groups of endocrine disrupting compounds in the ecosystem. These substances are present in sewage sludge that is spread in increasing amounts on arable land and pasture as fertilizer, and are ingested by farm animals with food and drinking water. This study investigated the effect of different PCB concentrations on p...

Soma-germline interactions control fertility at many levels, including stem cell proliferation, meiosis and gametogenesis, yet the nature of these fundamental signaling mechanisms and their potential evolutionary conservation are incompletely understood. In C. elegans, a sperm-sensing mechanism regulates oocyte meiotic maturation and ovulation, tightly coordinating sperm availability and fertil...

Maintaining oocytes at the germinal vesicle (GV) stage in vitro may permit enhanced acquisition of the developmental competence. The objective of the current study was to evaluate the nuclear and cytoplasmic maturation in vitro of porcine oocytes after pretreatment with S-roscovitine (ROS). Cumulus oocyte complexes (COC) were treated with 50 microM ROS for 48 h and then matured for various leng...

Immunofluorescent anti-tubulin staining has been used to follow nuclear progression from dictyate to metaphase II during meiotic maturation of mouse oocytes in vitro. Antibody directed against tubulin isolated from sea-urchin eggs decorates the metaphase I and metaphase II spindles, as well as the cytoplasmic bridge, midbody, and polar body of the maturing mouse oocytes. Changes in the tubulin-...

Progesterone causes a rapid increase in the intracellular free calcium level in fully grown amphibian oocytes. When albino Xenopus laevis oocytes were microinjected with the Ca-specific photoprotein aequorin, the calcium-induced luminescence from this protein increased at 40-60 sec after the addition of progesterone and returned to the control level within 5-6 min. No further change in the aequ...

Megakaryocytopoiesis and platelet production can be assessed with reasonable accuracy by quantitative and functional analyses of circulating platelets. The evaluation of megakaryocytopoiesis in culture has remained unsatisfactory, particularly because platelet production is rarely observed. In mouse culture systems, megakaryocytes have been identified almost entirely by measurements of acetyl c...

We used affinity-purified polyclonal antibodies to characterize the distribution and function of XMAP230, a heat-stable microtubule-associated protein isolated from Xenopus eggs, during oogenesis. Immunoblots revealed that XMAP230 was present throughout oogenesis and early development, but was most abundant in late stage oocytes, eggs, and early embryos. Immunofluorescence microscopy revealed t...

A continuous cell line of rhesus monkey kidney cells, LLC-MK(2), was infected with reovirus type 1 (Lang). The cells were freeze-etched as a method for observing the structural details of the reovirus-induced cytoplasmic inclusion. Information on maturation may be obtained by preparing infected cells for electron microscopy by freeze-etching.

A total of 15 morphological abnormalities characteristic of dyserythropoiesis were evaluated in bone marrow smears stained with May-Grunwald-Giemsa stain. Abnormalities were classified as: (a) anomalies of the nucleus (binuclearity, multinuclearity, nuclear lobulation, budding, fragmentation, chromatin lumping and pyknosis, intranuclear bridging, extrusion of the nucleus); and (b) anomalies of ...

Cytoplasmic polyadenylation controls the translation of several maternal mRNAs during Xenopus oocyte maturation and requires two sequences in the 3' untranslated region (UTR), the U-rich cytoplasmic polyadenylation element (CPE), and the hexanucleotide AAUAAA. c-mos mRNA is polyadenylated and translated soon after the induction of maturation, and this protein kinase is necessary for a kinase ca...