Topoisomerase II is an essential enzyme that is required for virtually every process that requires movement of DNA within the nucleus or the opening of the double helix. This enzyme helps to regulate DNA under- and overwinding and removes knots and tangles from the genetic material. In order to carry out its critical physiological functions, topoisomerase II generates transient double-stranded ...

A Caenorhabditis elegans mutant has been identified in which an ectopic myosin cap shifts the cleavage furrow relative to the spindle center. Surprisingly, the molecules that suppress this cap in wild-type embryos generate a cap in other asymmetrically dividing cells.

In cleaving eggs of the newt, Cynops pyrrhogaster, the behaviour of the egg surface was analysed by observing linear and area changes in a transplanted piece of cortex which differed in pigmentation from the background. Results from the animal hemisphere showed that the surface in the cleavage plane shrank extensively in the region where the early cleavage furrow was being formed. On both sides...

OBJECTIVES The objective of this study was to explore the influence of maternal prenatal characteristics and behaviors and of weight and BMI gain during early childhood on the timing of various puberty outcomes in girls who were enrolled in the Avon Longitudinal Study of Parents and Children. METHODS Repeated self-assessments of pubertal development were obtained from approximately 4000 girls...

et al., 1996, 1998). It is thus apparent that in-vitro matured 1Centre for Early Human Development, Institute of Reproduction human oocytes display meiotic but not developmental and Development, Level 5, Monash University, Monash Medical competence. Centre, 246 Clayton Road, Clayton, Victoria, Australia 3168 and 2Department of Obstetrics and Gynaecology, National University of Meiotic and devel...

The roles of purified Int and Xis proteins of the conjugative transposon Tn 916 in excision of a deletion derivative of the closely related element Tn 1545 were investigated. At a low salt concentration (37.5 mM NaCl), Int alone was able to promote limited excision to produce a covalently closed circular form of the transposon, showing that Tn 916 Int can catalyze both DNA cleavage and strand e...

CONTEXT AND OBJECTIVE Information on the correlation of normative reproductive hormone levels with physical development (Tanner stages) during puberty and on the influences of genes and environment on variation in these hormones and Tanner stages is limited. DESIGN, SETTING, AND PARTICIPANTS One hundred twelve healthy 9-year-old twin pairs (n = 224) took part in a longitudinal study, of which...

Different models for animal cell cytokinesis posit that the stiffness of the equatorial cortex is either increased or decreased relative to the stiffness of the polar cortex. A recent work has suggested that the critical cytokinesis signaling complex centralspindlin may reduce the stiffness of the equatorial cortex by inactivating the small GTPase Rac. To determine if such a reduction occurs an...