The reversible oxidative inactivation of transcription factors has been proposed to be important in cellular responses to oxidant stress and in several signal transduction pathways. The nuclear factor I (NFI) family of transcription factors is sensitive to oxidative inactivation due to the presence of a conserved, oxidation-sensitive cysteine residue within the NFI DNA-binding domain. Here we s...

The synthesis of heat shock proteins (HSP) and the development of thermotolerance were studied in Chinese hamster ovary cells in order to determine whether depletion of intracellular glutathione (GSH) inhibited their expression. Cells were exposed to 100 microM diethylmaleate/50 microM buthionine sulfoximine which reduced GSH levels by 95% or more during the experimental time course. HSP synthe...

To investigate the regulation of HvNRT2, genes that encode high-affinity NO(3)(-) transporters in barley (Hordeum vulgare) roots, seedlings were treated with 10 mM NO(3)(-) in the presence or absence of amino acids (aspartate, asparagine, glutamate [Glu], and glutamine [Gln]), NH(4)(+), and/or inhibitors of N assimilation. Although all amino acids decreased high-affinity (13)NO(3)(-) influx and...

A positive selection method for isolation of nitrogenase-derepressed mutant strains of a filamentous cyanobacterium, Anabaena variabilis, is described. Mutant strains that are resistant to a glutamate analog, L-methionine-D,L-sulfoximine, were screened for their ability to produce and excrete NH4' into medium. Mutant strains capable of producing nitrogenase in the presence of NH4' were selected...

GSH delivery to the lactating mammary gland is essential for the maintenance of lactation as its decrease leads to apoptosis and involution of the mammary gland. In fact, it has already been demonstrated that some of the changes in gene expression found in the lactating mammary gland after forced weaning are reproduced in rats treated with buthionine sulphoximine to deplete GSH levels. An oligo...

To understand how traits used in animal communication evolved and are maintained as honest signals, we need to understand the mechanisms that prevent cheating. It has been proposed that honest signaling is guaranteed by the costs associated with the signal expression. However, the nature of these costs is still under debate. Melanin-based signals are intriguing because their expression seems to...

Illuminated pea (Pisum sativum) chloroplasts actively catalyzed (glutamine plus alpha-ketoglutarate)-dependent O(2) evolution (average of 12 preparations 10.6 mumole mg chlorophyll per hour). The reaction was specific for glutamine and alpha-ketoglutarate; concentrations of 0.2 mm alpha-ketoglutarate and 0.6 mm glutamine, respectively, effected half-maximum rates of O(2) evolution. The reaction...

Glutamine synthetase, purified from rat liver, is homogeneous on acrylamide gel electrophoresis and on ultracentrifugation (~20,~) 15.0 S). The enzyme, which consists of eight subunits (subunit molecular weight, 44,000), resembles ovine brain glutamine synthetase in its physical properties, amino acid composition, and substrate specificity. Complete inhibition of the liver enzyme by methionine ...

Previous studies with cystinuric dogs and humans have demonstrated that the amount of cystine excreted in the urine is, in some cases, larger than the amount of cystine removed from the plasma by glomerular filtration. It was concluded that the kidney must secrete cystine into the renal tubule. The present studies indicate that renal glutathione turnover constitutes a mechanism of cystine secre...

Long BGO (Bi4Ge3O12) and BSO (Bi4Si3O12) crystals coupled with silicon photodiodes have been used to detect minimumionizing particles(MIP). With a low noise amplifier customized for this purpose, the crystals can detect MIPs with an excellent signalto-noise ratio. The nuclear counter effect is also clearly observed and measured. Effect of full and partial wrapping of a reflector around the crys...