Life Sciences Commons^™

Developmental Regulation Of A Cyclin-Dependent Kinase Inhibitor Controls Postembryonic Cell Cycle Progression In Caenorhabditis Elegans, Yang Hong, Richard Roy, Victor Ambros

Victor R. Ambros

C. elegans cki-1 encodes a member of the CIP/KIP family of cyclin-dependent kinase inhibitors, and functions to link postembryonic developmental programs to cell cycle progression. The expression pattern of cki-1::GFP suggests that cki-1 is developmentally regulated in blast cells coincident with G1, and in differentiating cells. Ectopic expression of CKI-1 can prematurely arrest cells in G1, while reducing cki-1 activity by RNA-mediated interference (RNAi) causes extra larval cell divisions, suggesting a role for cki-1 in the developmental control of G1/S. cki-1 activity is required for the suspension of cell cycling that occurs in dauer larvae and starved L1 larvae in …

Identification Of A Rapd Marker Linked To Progressive Rod-Cone Degeneration In Dogs, Weikuan Gu, Gregory M. Acland, Amelia A. Langston, Elaine A. Ostrander, Gustavo D. Aguirre, Kunal Ray

Gustavo D. Aguirre, VMD, PhD

Degradation Signal Masking By Heterodimerization Of Mata2 And Mata1 Blocks Their Mutual Destruction By The Ubiquitin-Proteasome Pathway, Rob Swanson, Phoebe R. Johnson, Larissa Rakhilina, Mark Hochstrasser

Rob Swanson

Proteolysis by the ubiquitin-proteasome pathway is often regulated, but the mechanisms underlying such regulation remain ill-defined. In Saccharomyces cere-visiae, cell type is controlled by the MAT transcription factors. The a2repressor is a known ubiquitinpathway substrate in a haploid cells. We show that a1 is rapidly degraded in a haploids. In a/a diploids, a2 and a1 are stabilized by heterodimerization. Association depends on N-terminal coiled-coil interactions between a1 and a2. Residues in a2 important for these interactions overlap a critical determinant of an a2 degradation signal, which we delimit by extensive mutagenesis. Our data provide a detailed description of a natural …

Involvement Of Heme In The Degradation Of Iron-Regulatory Protein 2, Lisa Goessling, David Mascotti, Robert Thach

David P. Mascotti

ron-regulatory proteins (IRPs) recognize and bind to specific RNA structures called iron-responsive elements. Mediation of these binding interactions by iron and iron-containing compounds regulates several post-transcriptional events relevant to iron metabolism. There are two known IRPs, IRP1 and IRP2, both of which can respond to iron fluxes in the cell. There is ample evidence that IRP1 is converted by iron to cytoplasmic aconitase in vivo. It has also been shown that, under certain conditions, a significant fraction of IRP1 is degraded in cells exposed to iron or heme. Studies have shown that the degradation of IRP1 that is induced by …

Darwinism And Developmentalism: Prospects For Convergence, David Depew

David J Depew

No abstract provided.

Growth And Reproductive Performance Of Small Ruminants Under Integrated Livestock Oil Palm Production System, Ahmad Salihin Hj Baba, Azillah A., Mukherjee T. K., Abdullah R. B.

Ahmad Salihin Hj Baba

The effects of supplementation with mixed fodder or concentrate were investigated on the performance of a) growth of male lambs;md kids grazing extensively under oil palm trees and b) reproduction of ewes and goats stall-fed with native herbage. Supplemented kids and lambs had higher average daily weight gain than controls but the effect was only significant for those which received concentrate (p < 0.05). Final body weight was only significantly different from controls for lambs supplemented with concentrate (p < 0.05). The ages at puberty, first mating, first conception and first kidding of supplemented goats were about 110 days earlier than those for controls (p < 0.05 or better). Supplemented goats had first mating and conceived at lower body weights (p < 0.01) than those in control groups. Different feeding regimes had no effects (p > 0.05) on the reproductive performance of ewes apart fi om highest body weight of first lambing in animals supplemented with concentrate (p < 0.05). Native herbage available under oil palm trees of 5 years old was sufficient for growth …

Root Growth, Developmental Changes In The Apex, And Hydraulic Conductivity For Opuntia Ficus-Indica During Drought, J. Dubrovsky, Gretchen North, P. Nobel

Gretchen North

Developmental changes in the root apex and accompanying changes in lateral root growth and root hydraulic conductivity were examined for Opuntia ficus-indica (L.) Miller during rapid drying, as occurs for roots near the soil surface, and more gradual drying, as occurs in deeper soil layers. During 7 d of rapid drying (in containers with a 3-cm depth of vermiculite), the rate of root growth decreased sharply and most root apices died; such a determinate pattern of root growth was not due to meristem exhaustion but rather to meristem mortality after 3 d of drying. The length of the meristem, the …

Gall-Inducing Insects Provide Insights Into Plant Systematic Relationships, Warren Abrahamson, G. Melika, R. Scrafford, G. Csoka

Warren G. Abrahamson, II

No abstract provided.

The Temporal Correlation Of Changes In Apoplast Ph And Growth Rate In Maize Coleoptile Segments, Winfried Peters, Hartwig Lüthen, Michael Böttger, Hubert Felle

Winfried S. Peters

The Effect Of Mismatch Repair And Heteroduplex Formation On Sexual Isolation In Bacillus, Jacek Majewski, Frederick M. Cohan

Frederick M. Cohan

No abstract provided.