The killer yeast species Pichiaacaciae produces a heteromeric killer protein, PaT, that causes DNA damage and arrests the cell cycle of sensitive Saccharomyces cerevisiae in the S phase. However, the mechanism by which DNA damage occurs remains elusive. A previous study has indicated that Orf2p, a subunit of PaT, specifically cleaves an anticodon loop of an S. cerevisiae transfer RNA (tRNA(Gln)...

Allomyces macrogynus produces zoosporangia that discharge uninucleate zoospores after cleavage of multinucleate cytoplasm. Cleavage of cytoplasm within the oligonucleate zoosporangia of A. macrogynus was visualized by constructing three-dimensional models based on electron micrographs and confocal images. In oligonucleate zoosporangia, three adjacent nuclei can form three cleavage planes with a...

Talin is a large (∼2540 residues) dimeric adaptor protein that associates with the integrin family of cell adhesion molecules in cell-extracellular matrix junctions (focal adhesions; FAs), where it both activates integrins and couples them to the actin cytoskeleton. Calpain2-mediated cleavage of talin between the head and rod domains has previously been shown to be important in FA turnover. Her...

Background: The aim of our study was to compare the resulting from transfer of embryos that cryopereserved in cleavage stage after thawing and transfer of embryos after thawing and culture in sequentional media until blastocyst formation. Materials and Methods: In this prospective clinical study, we have evaluated 128 cycles in women undergone in vitro fertilization (IVF) or intracytoplasmic sp...

a. Cleavage In vertebrates, cell division is radial and indeterminate. The first mitotic cell divisions that follow fertilization occur rapidly and are not accompanied by cell growth. The In many animals (mammals are an exception), the zygote has a definite polarity. As a result, the cleavage divisions create cells that differ in their cytoplasmic contents (e.g., cytoplasmic determinants: mRNAs...

The sensitivity of early preimplantation mouse embryos to drugs which disrupt microfilament function (cytochalasin B-CB and cytochalasin D-CD and microtubule assembly (colchicine, colcemid, vinblastine and griseofulvin) was examined. CD inhibited cleavage at a concentration 35-fold lower than CB (3 X 10-7 M v. 1 X 10-5 M). Treatment of 2-cell embryos for 6 h with 1 X 10-5 M CB or 1 X 10-6 M CD...