The eye primordium of the moth, Manduca sexta, shows two different developmental responses to ecdysteroids depending on the concentration to which it is exposed. Tonic exposure to moderate levels of 20-hydroxyecdysone (20E) or its precursor, ecdysone, are required for progression of the morphogenetic furrow across the primordium. Proliferation, cell-type specification and organization of immatu...

Loss of function mutations of scabrous and conditional alleles of Notch and Delta affect the pattern of morphogenetic furrow development. By studying differentiation of R8 cells, the first photoreceptor neuron subtype to differentiate, we show that all furrow cells pass through an R8-competent stage. Function of Notch and scabrous is necessary if most of these cells are to attain other cell fat...

Morphogenesis involves the interplay of different cytoskeletal regulators. Investigating how they interact during a given morphogenetic event will help us understand animal development. Studies of ventral furrow formation, a morphogenetic event during Drosophila gastrulation, have identified a signaling pathway involving the G-protein Concertina (Cta) and the Rho activator RhoGEF2. Although the...

INTRODUCTION Contractile networks are fundamental to many cellular functions, particularly cytokinesis and cell motility. Contractile networks depend on myosin-II mechanochemistry to generate sliding force on the actin polymers. However, to be contractile, the networks must also be crosslinked by crosslinking proteins, and to change the shape of the cell, the network must be linked to the plasm...

soil infiltration characteristics affect the design, evaluation and management of furrow irrigation over afield. on the other hand, different variables influence furrow infiltration, making infiltration modeling for afield a complex process. this study was conducted to investigate the direct and indirect effects of allvariables affecting furrow infiltration. the blocked furrow method was used t...

*R. D. Lentz and D.L. Bjorneberg, USDA-ARS, Northwest Irrigation and Soils Research Lab., 3793 N. 3600 E., Kimberly, ID 83341 USA. *Corresponding author: [email protected] ABSTRACT For surface irrigation, the rate and spatial characteristics of infiltration processes influence crop productivity, water use efficiency, and erosion potential of stream flows. A change in infiltration rate a...

BACKGROUND During cytokinesis in animal cells, an equatorial actomyosin-based contractile ring divides the cell into two daughter cells. The position of the contractile ring is specified by a signal that emanates from the mitotic spindle. This signal has not been identified and it is not understood how the components of the contractile ring assemble. It is also unclear how the ring constricts o...

The first event of Drosophila gastrulation is the formation of the ventral furrow. This process, which leads to the invagination of the mesoderm, is a classical example of epithelial folding. To understand better the cellular changes and dynamics of furrow formation, we examined living Drosophila embryos using three-dimensional time-lapse microscopy. By injecting fluorescent markers that visual...

Through the injection of f-aequorin (a calcium-specific luminescent reporter) and the use of an imaging photon detector, we see a distinct localized elevation of intracellular calcium that accompanies the appearance of the first furrow arc at the blastodisc surface: the furrow positioning signal. As the leading edges of the arc progress outward toward the margins of the blastodisc, they are acc...

* Department of Soil Science, Punjab Agricultural University, Ludhiana 141 004 Abstract: Different irrigation methods and regimes affect maize (Zea Mays L.) growth differently. The field experiment was conducted to study the interactive effect of three irrigation methods and three irrigation regimes on maize growth under sandy loam soil at the Research Farm of Department of Soil Science, Punjab...