The imino amino acid, proline, has roles in both cellular nutrition and response to stress. Proline uptake in Saccharomyces cerevisiae is largely mediated by a high affinity, specific permease, Put4p, and a low affinity general amino acid permease, Gap1p. Both are subject to nitrogen catabolite repression (NCR) and nitrogen catabolite inactivation (NCI). In order for proline to be fully exploit...

Arginine is conditionally indispensable in the neonate, and its synthesis in the intestine is not sufficient to meet requirements. It is not known how neonatal endogenous arginine synthesis is regulated and the degree to which proline and glutamate are used as precursors. Primed, constant intraportal and intragastric infusions of L-[U-14C]proline and L-[3,4-3H]glutamate, and intragastric L-[gua...

Actively growing Escherichia coli cells respond to increased osmotic pressure by increasing their internal pools of K+ (Epstein & Schultz, 1965) and of the amino acids glutamate, proline and a-aminobutyric acid (Britten & McClure, 1962; Measures, 1975). The change in amino acid pools may be brought about either by increased rates of their synthesis or by stimulation of the rate of their uptake....

The functions of two conserved residues, Phe(135) and Pro(136), located at the apex of the Cys loop of the nicotinic acetylcholine receptor are investigated. Both residues were substituted with natural and unnatural amino acids, focusing on the role of aromaticity at Phe(135), backbone conformation at Pro(136), side chain polarity and volume, and the specific interaction between the aromatic si...

An interesting observation, reported for transgenic plants that have been engineered to overproduce osmolytes, is that they often exhibit impaired growth in the absence of stress. As growth reduction and accumulation of osmolytes both typically result from adaptation, we hypothesized that growth reduction may actually result from osmolyte accumulation. To examine this possibility more closely, ...

Seasonal changes in antioxidant enzymes activities, amount of water, ash, proline and soluble sugars were surveyed during this research in four halophyte species of Varamin County, Tehran, Iran: Salsola turcomanica Litwin, Suaeda arcuata Bunge, Tamarix leptopetala Bunge and Cressa cretica L. Plants were collected randomly from their natural habitats in spring and summer. Activity of these enzym...

Drought stress is the major problem in arid and semi-arid regions of the world. Investigating the response of different cultivars of crop plants to drought stress can help to select the tolerant ones for agriculture in arid lands. In this study, a greenhouse experiment was conducted as a factorial experiment based on completely randomized design with two common bean cultivars (Phaseolus vulgari...