In the eggs of the newt, Cynops (Triturus) pyrrhogaster, change in stiffness of the cortex was measured in various regions at the time of the cleavage. Measurements were performed by Mitchison and Swann's cell elastimeter method with a modification, in which two fine pipettes were attached to the surface of one egg at the same time, in order to compare the rigidity of two regions. The stiffness...

L cells exposed to cytochalasin-B (cyto-B) show the normal development of deep cleavage furrows in both bipolar and multipolar cell divisions Due to the drug-induced inhibition of cellular motility, the resulting daughter cells do not move away from each other but reunite to form multinucleate cells. In mitotic cells from cultures exposed to cyto-B for long periods of time, vigorous blebbing an...

During early development, control of the poly(A) tail length by cytoplasmic polyadenylation is critical for the regulation of specific mRNA expression. Gld2, an atypical poly(A) polymerase, is involved in cytoplasmic polyadenylation in Xenopus oocytes. In this study, a new XGld2-interacting protein was identified: Xenopus RNA-binding motif protein 9 (XRbm9). This RNA-binding protein is exclusiv...

The suppressor of forked (Su(f)) protein of Drosophila melanogaster is highly homologous to two proteins involved in mRNA 3'-end formation, the yeast RNA14 protein and the 77K subunit of human cleavage stimulation factor (CstF). This suggests a role for su(f) in mRNA 3'-end-processing, probably as part of Drosophila CstF. We have investigated the expression pattern of su(f) during Drosophila de...

The DNA cleavage reaction of human topoisomerase IIalpha is critical to all of the physiological and pharmacological functions of the protein. While it has long been known that the type II enzyme requires a divalent metal ion in order to cleave DNA, the role of the cation in this process is not known. To resolve this fundamental issue, the present study utilized a series of divalent metal ions ...

High-resolution mapping of topol cleavages in the regions of human DNA including the oncogene c-Ha-ras and p53, has revealed three kinds of topol cleavage sites: cleavage sites not affected by camptothecin; cleavage sites reinforced only in the presence of camptothecin, and cleavage sites which weaken in the presence of camptothecin. Statistical analysis of sequences revealed certain nucleotide...

Background: Decreasing the growth and developmental rate of embryo and arresting in certain step of development like two cell block could be the reason of infertility in some couples referring to fertility and infertility center. The aim of this study is the effect of strontium on growth and development of two-cell arrested NMRI mouse embryo. Materials and Methods: The female mice were coupled ...

Background The purpose was to investigate the effect of the duration of gamete incubation on fertilization rate, embryo cleavage, and embryo quality before and after freezing in mice. MaterialsAndMethods Ovulated oocytes collected from superovulated mice after ip injection of PMSG and hCG were divided randomly into control and experimental groups. Oocytes from the control group were inseminated...