in order to increase grain yield, nitrogen use efficiency (nue) and nitrogen apparent recovery fraction (narf) in wheat (triticum aestivum l.), this experiment was carried out with 5 or 6 treatments and 3 or 4 replications in 14 locations at 22 different sites in iran during the 2004-05 growing season. the experiment was designed as a completely randomized block. the effect of n sources and tim...

background: like several other parasites, teladorsagia circumcincta secretes or excretes urea, but nei-ther the rate of efflux nor the possible metabolic sources of the urea has been considered. methods: parasites were maintained by passage through sheep. urea efflux was measured using phe-nol/hypochlorite after treatment with urea aminohydrolase. the kinetics of creatine amidinohy-drolase and ...

In the dinuclear title compound, [Cu2I2(C3H8N2S)(C25H22P2)2]·1.5CH3CN, each Cu(I) atom exhibits a distorted tetra-hedral coordination with two P atoms from two bis-(diphenyl-phosphan-yl)methane (dppm) ligands, one metal-bridging S atom from the 1-ethyl-thio-urea (ettu) ligand and one iodide ion. The dppm ligand and the bridging S atom of the ettu ligand force the two copper atoms into close pro...

The NOTCH1 receptor is cleaved within its extracellular domain by furin during its maturation, yielding two subunits that are held together noncovalently by a juxtamembrane heterodimerization (HD) domain. Normal NOTCH1 signaling is initiated by the binding of ligand to the extracellular subunit, which renders the transmembrane subunit susceptible to two successive cleavages within and C termina...

Gene expression can be controlled in genetically modified cells by employing an inducer/promoter system where presence of the inducer molecule regulates the timing and level of gene expression. By applying the principles of controlled release, it should be possible to control gene expression on a biomaterial surface by the presence or absence of inducer release from the underlying material matr...

The search for small-molecule drugs that act at peptide hormone receptors has resulted in the identification of a wide variety of antagonists. In contrast, the discovery of nonpeptide agonists has been far more elusive. We have used a constitutively active mutant of the cholecystokinin 2 receptor (CCK-2R) as a sensitive screen to detect ligand activity. Functional assessment of structural analo...

Allosteric binding pockets in peptide-binding G protein-coupled receptors create opportunities for the development of small molecule drugs with substantial benefits over orthosteric ligands. To gain insights into molecular determinants for this pocket within type 1 and 2 cholecystokinin receptors (CCK1R and CCK2R), we prepared a series of receptor constructs in which six distinct residues in TM...

When behavioral avoidance cannot prevent an animal from being exposed to novel environmental toxins, physiological mechanisms must cope with the toxin and its effects. We are investigating the basis of urea tolerance in populations of Drosophila melanogaster that have been selected to survive and develop in food containing 300 mmol l(-1) urea. Previous research has demonstrated that the urea-se...