Living with water stress: evolution of osmolyte systems
24 Sep 1982-Science (American Association for the Advancement of Science)-Vol. 217, Iss: 4566, pp 1214-1222
TL;DR: Osmolyte compatibility is proposed to result from the absence of osmolytes interactions with substrates and cofactors, and the nonperturbing or favorable effects of oSMolytes on macromolecular-solvent interactions.
Abstract: Striking convergent evolution is found in the properties of the organic osmotic solute (osmolyte) systems observed in bacteria, plants, and animals Polyhydric alcohols, free amino acids and their derivatives, and combinations of urea and methylamines are the three types of osmolyte systems found in all water-stressed organisms except the halobacteria The selective advantages of the organic osmolyte systems are, first, a compatibility with macromolecular structure and function at high or variable (or both) osmolyte concentrations, and, second, greatly reduced needs for modifying proteins to function in concentrated intracellular solutions Osmolyte compatibility is proposed to result from the absence of osmolyte interactions with substrates and cofactors, and the nonperturbing or favorable effects of osmolytes on macromolecular-solvent interactions
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01 Jun 2000
TL;DR: Evidence for plant stress signaling systems is summarized, some of which have components analogous to those that regulate osmotic stress responses of yeast, some that presumably function in intercellular coordination or regulation of effector genes in a cell-/tissue-specific context required for tolerance of plants.
Abstract: ▪ Abstract Plant responses to salinity stress are reviewed with emphasis on molecular mechanisms of signal transduction and on the physiological consequences of altered gene expression that affect biochemical reactions downstream of stress sensing. We make extensive use of comparisons with model organisms, halophytic plants, and yeast, which provide a paradigm for many responses to salinity exhibited by stress-sensitive plants. Among biochemical responses, we emphasize osmolyte biosynthesis and function, water flux control, and membrane transport of ions for maintenance and re-establishment of homeostasis. The advances in understanding the effectiveness of stress responses, and distinctions between pathology and adaptive advantage, are increasingly based on transgenic plant and mutant analyses, in particular the analysis of Arabidopsis mutants defective in elements of stress signal transduction pathways. We summarize evidence for plant stress signaling systems, some of which have components analogous to t...
4,596 citations
TL;DR: In this review article, numerous examples of successful application of these compounds to improve plant stress tolerance are presented and a better understanding of the mechanisms of action of exogenously applied GB and proline is expected to aid their effective utilization in crop production in stress environments.
3,847 citations
TL;DR: The ability of plants to tolerate salt is determined by multiple biochemical pathways that facilitate retention and/or acquisition of water, protect chloroplast functions, and maintain ion homeostasis as mentioned in this paper.
3,546 citations
TL;DR: The responses of plants to salt and water stress are described, the regulatory circuits which allow plants to cope with stress are presented, and how the present knowledge can be applied to obtain tolerant plants is discussed.
Abstract: Agricultural productivity worldwide is subject to increasing environmental constraints, particularly to drought and salinity due to their high magnitude of impact and wide distribution. Traditional breeding programs trying to improve abiotic stress tolerance have had some success, but are limited by the multigenic nature of the trait. Tolerant plants such as Craterostigma plantagenium, Mesembryanthemum crystallinum, Thellungiella halophila and other hardy plants could be valuable tools to dissect the extreme tolerance nature. In the last decade, Arabidopsis thaliana, a genetic model plant, has been extensively used for unravelling the molecular basis of stress tolerance. Arabidopsis also proved to be extremely important for assessing functions for individual stress-associated genes due to the availability of knock-out mutants and its amenability for genetic transformation. In this review, the responses of plants to salt and water stress are described, the regulatory circuits which allow plants to cope wit...
2,351 citations
Cites background from "Living with water stress: evolution..."
...These molecules may have a primary role of turgor maintenance but they may also be involved in stabilizing proteins and cell structures (Yancey et al., 1982)....
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TL;DR: The major strategies for designing surfaces that prevent fouling due to proteins, bacteria, and marine organisms are reviewed and ongoing research in this area should result in the development of even better antifouling materials in the future.
Abstract: The major strategies for designing surfaces that prevent fouling due to proteins, bacteria, and marine organisms are reviewed. Biofouling is of great concern in numerous applications ranging from biosensors to biomedical implants and devices, and from food packaging to industrial and marine equipment. The two major approaches to combat surface fouling are based on either preventing biofoulants from attaching or degrading them. One of the key strategies for imparting adhesion resistance involves the functionalization of surfaces with poly(ethylene glycol) (PEG) or oligo(ethylene glycol). Several alternatives to PEG-based coatings have also been designed over the past decade. While protein-resistant coatings may also resist bacterial attachment and subsequent biofilm formation, in order to overcome the fouling-mediated risk of bacterial infection it is highly desirable to design coatings that are bactericidal. Traditional techniques involve the design of coatings that release biocidal agents, including antibiotics, quaternary ammonium salts (QAS), and silver, into the surrounding aqueous environment. However, the emergence of antibiotic- and silver-resistant pathogenic strains has necessitated the development of alternative strategies. Therefore, other techniques based on the use of polycations, enzymes, nanomaterials, and photoactive agents are being investigated. With regard to marine antifouling coatings, restrictions on the use of biocide-releasing coatings have made the generation of nontoxic antifouling surfaces more important. While considerable progress has been made in the design of antifouling coatings, ongoing research in this area should result in the development of even better antifouling materials in the future.
2,278 citations
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2,462 citations
TL;DR: The objective was to establish an experimental procedure and show direct AFM measurements that unequivocally can be assigned as a mode of action for the conversion of NalK to Na6(SO4)(SO3) during the cycling process.
Abstract: INTRODUCTION 89 BACKGROUND: THE BASIC PHYSIOLOGY 91 Conclusions 9S ION RELATIONS 96' Ion Uptake and Osmotic Adjustment 96 Nutrient Uptake: NalK Specificity 99 Ion Distribution within the Plant 100 Ion Distribution within the Cell 100 Metabolic evidence 100 Physical measurements .... .... ......... ...... 104 Energetics 106 ROLE OF ORGANIC SOLUTES ........ 108 OrganiC Acids 108 Nitrogen Compounds 109 Carbohydrotes 110 CONCLUSIONS 114
1,959 citations
TL;DR: A densimetric investigation of the interactions between solvent components in glycerol-water mixtures and seven proteins and all the proteins were found to be preferentially hydrated at all conditions used, i.e., addition of the proteins to the mixed solvent results in an increase in the chemical potential of Glycerol.
Abstract: A densimetric investigation of the interactions between solvent components in glycerol-water mixtures (between 10 and 40 vol % glycerol) and seven proteins have been carried out in the acid pH region. All the proteins were found to be preferentially hydrated at all conditions used, i.e., addition of the proteins to the mixed solvent results in an increase in the chemical potential of glycerol. It is considered that this thermodynamically unfavorable interaction should tend to minimize the surface of contact between proteins and glycerol and in this way stabilize the native structure of globular proteins.
1,172 citations
TL;DR: It is argued that, notwithstanding the indispensability of water in living systems and the unique properties of solvent water, quantitative variations in the amount of water available are of less direct microbiological significance than is generally conceded.
Abstract: A fellow of my acquaintance, on seeing a colleague drink undiluted water (55.5 molal), has been known to comment in disapproval that water at such a concentration should not be used for that purpose and that its main function is for putting around the outside of boats. He conceded that dilution with a little salt is acceptable for boats but for no other purpose. The proponent of this philosophy is not a biologist and it is unlikely that many biologists would accept his generalization without some qualification. Nevertheless, it is a point of view. Another point of view with which all biologists might not agree, at least initially, is one which I wish to advance in this review. It is that, notwithstanding the indispensability of water in living systems and the unique properties of solvent water, quantitative variations in the amount of water available are of less direct microbiological significance than is generally conceded.
798 citations