In the evaluation of the risk of pesticide leaching to groundwater, the soil surface is usually assumed to be level, although important crops like potato are grown on ridges. A fraction of the water from rainfall and sprinkler irrigation may flow along the soil surface from the ridges to the furrows, thus bringing about an extra load of water and pesticide on the furrow soil. A survey of the li...

After the separation of sister chromatids in anaphase, it is essential that the cell position a cleavage furrow so that it partitions the chromatids into two daughter cells of roughly equal size. The mechanism by which cells position this cleavage furrow remains unknown, although the best current model is that furrows always assemble midway between asters. We used micromanipulation of human cul...

At the end of the cell cycle a cell physically divides into two daughter cells in a process called cytokinesis. Cytokinesis consists of at least four steps: (1) The position of the presumptive cytokinesis furrow is specified. (2) A contractile ring is formed. (3) The contractile ring contracts, resulting in furrow ingression. (4) Cytokinesis completes with sealing of the membranes. The mitotic ...

Animal cells decide where to build the cytokinetic apparatus by sensing the position of the mitotic spindle. Reflecting a long-standing presumption that a furrow-inducing stimulus travels from spindle to cortex via microtubules, debate continues about which microtubules, and in what geometry, are essential for accurate cytokinesis. We used live imaging in urchin and frog embryos to evaluate the...

Differentiation of the Drosophila eye imaginal disc is an asynchronous, repetitive process which proceeds across the disc from posterior to anterior. Its propagation correlates with the expression of decapentaplegic at the front of differentiation, in the morphogenetic furrow. Both differentiation and decapentaplegic expression are maintained by Hedgehog protein secreted by the differentiated c...

The fact that substrate-anchored Dictyostelium cells undergo cytokinesis in the absence of myosin II underscores the importance of other proteins in enabling the cleavage furrow to constrict. Cortexillins, a pair of actin-bundling proteins, are required for normal cleavage. They are targeted to the incipient furrow in wild-type and, more prominently, in myosin II-null cells. No other F-actin bu...

OBJECTIVE To describe a technique of subcutaneous superficial musculoaponeurotic system grafting during rhytidectomy to treat the aging melolabial furrow. DESIGN Two hundred seventeen patients received bilateral superficial musculoaponeurotic system grafts from December 1, 1996, through June 30, 2003 (a 78-month period). The patients' charts were reviewed for demographic data, follow-up dates...

The interactive influence of furrow surface seal formation and surge irrigation (intermittent flow) on furrow infiltration into a Portneuf silt loam soil was measured with a recirculating infiltrometer. When the formation of a surface seal was prevented by a layer of cheesecloth laid on the furrow perimeter, flow interruption increased furrow bed bulk density by 100 kg/m 3 and decreased infiltr...

A cytoplasmic factor and a cortical factor participating in cleavage furrow formation had been previously found in Cynops eggs (Sawai, 1972). These were investigated in the present study in Ambystoma and Xenopus eggs, by the method of cytoplasmic or cortical transplantation. Results were practically similar to those previously obtained with Cynops, indicating that in all the species of eggs dur...

The GTPase RhoA promotes contractile ring assembly and furrow ingression during cytokinesis. Although many factors that regulate RhoA during cytokinesis have been characterized, the spatiotemporal regulatory logic remains undefined. We have developed an optogenetic probe to gain tight spatial and temporal control of RhoA activity in mammalian cells and demonstrate that cytokinetic furrowing is ...