Temperature- and concentration-dependence of compatibility of the organic osmolyte β-dimethylsulfoniopropionate
80
Citation
30
Reference
10
Related Paper
Citation Trend
Keywords:
Osmolyte
Dimethylsulfoniopropionate
Denaturation (fissile materials)
Cryoprotectant
Osmolyte
Dimethylsulfoniopropionate
Osmoregulation
Betaine
Cite
Citations (89)
Among various abiotic stresses, salinity is a major problem in arid and semiarid regions of the world that negatively reduces the crop productivity. Osmotic stress is the major cause of reduction in growth under salt stress and to minimize the osmotic stress, plants either accumulates or enhances the synthesis of osmoprotectants. The enhanced production of osmolytes is the manifestation of osmoprotectant responsive genes, which improves stress tolerance in plants. Most of the crop plants during abiotic stress conditions such as salinity, drought, and high temperature protect themselves through amino acid metabolism as well. Salinity is one of the most brutal environmental stresses that hamper plant growth and productivity worldwide. The biosynthetic pathways of major osmolyte such as proline, glycine betaine, polyamines, or some synthetic sugar molecules are severely affected under salt stress. Salt-induced toxicity is either alleviated by enhanced antioxidant system or by exogenous supplementation of these major osmolytes.
Osmolyte
Betaine
Osmotic shock
Osmoregulation
Cite
Citations (0)
Extreme ecological surroundings for plants such as drought and water scarcity, varying temperature from minimal to maximum level, and accumulation of salt and heavy metals diminish plant growth and hence need precise alteration or modification. To maintain osmotic harmony, plants secrete osmolytes and osmoprotectants as essential abiotic stress mitigators to encounter harsh environmental conditions through monitoring constant cellular homeostatic. There are some low-molecular-weight, nontoxic compounds that accumulate in plants in response to drought and salinity stress without snooping with normal metabolism. Soluble sugars such as sucrose, hexose, trehalose, RFO, and sugar alcohols and other osmolytes such as glycine betaine and proline amino acid act as the osmoprotectants. These sugars play an important role in the maintenance of cellular organizations, photosynthetic proficiency, and detoxification of reactive oxygen species by acting as metabolic signals in the stress conditions. Together, they shield plants by exercising a number of physiological responses, such as strengthening membrane integrity, harmonizing enzymatic/antioxidant activity, and fulfilling water requirement under several abiotic stresses including pesticide exposure. In spite of the fact that a connection surely exists between the amassing of explicit osmoprotective substances and stress tolerance, a causal connection between osmolyte gathering and improved resistance could not generally be affirmed. This chapter enlightens the mechanisms potentially involved in plant abiotic stress tolerance brought by osmoprotectants as well as concisely highlights important parts so far unmapped in the present framework.
Osmolyte
Betaine
Osmoregulation
Osmotic shock
Cite
Citations (52)
Dimethylsulfoniopropionate (DMSP), a key component of the global geochemical sulfur cycle, is a secondary metabolite produced in large quantities by marine phytoplankton and utilized as an osmoprotectant, thermoprotectant and antioxidant. Marine bacteria can use two pathways to degrade and catabolize DMSP, a demethylation pathway and a cleavage pathway that produces the climate active gas dimethylsulfide (DMS). Whether marine bacteria can also accumulate DMSP as an osmoprotectant to maintain the turgor pressure of the cell in response to changes in external osmolarity has received little attention. The marine halophile Vibrio parahaemolyticus, contains at least six osmolyte transporters, four betaine carnitine choline transport (BCCT) carriers BccT1-BccT4 and two ABC-family ProU transporters. In this study, we showed that DMSP is used as an osmoprotectant by V. parahaemolyticus and several other Vibrio species including V. cholerae and V. vulnificus Using a V. parahaemolyticus proU double mutant, we demonstrated that these ABC transporters are not required for DMSP uptake. However, a bccT null mutant lacking all four BCCTs had a growth defect compared to wild type in high salinity media supplemented with DMSP. Using mutants possessing only one functional BCCT in growth pattern assays, we identified two BCCT-family transporters, BccT1 and BccT2, which are carriers of DMSP. The only V. parahaemolyticus BccT homolog that V. cholerae and V. vulnificus possess is BccT3 and functional complementation in Escherichia coli MKH13 showed V. cholerae VcBccT3 could transport DMSP. In V. vulnificus strains, we identified and characterized an additional BCCT family transporter, which we named BccT5 that was also a carrier for DMSP.Importance DMSP is present in the marine environment, produced in large quantities by marine phytoplankton as an osmoprotectant, and is an important component of the global geochemical sulfur cycle. This algal osmolyte has not been previously investigated for its role in marine heterotrophic bacterial osmotic stress response. Vibrionaceae are marine species, many of which are halophiles exemplified by V. parahaemolyticus, a species that possesses at least six transporters for the uptake of osmolytes. Here, we demonstrated that V. parahaemolyticus and other Vibrio species can accumulate DMSP as an osmoprotectant and show that several BCCT family transporters uptake DMSP. These studies suggest that DMSP is a significant bacterial osmoprotectant, which may be important for understanding the fate of DMSP in the environment. DMSP is produced and present in coral mucus and Vibrio species form part of the microbial communities associated with them. The function of DMSP in these interactions is unclear, but could be an important driver for these associations allowing Vibrio proliferation. This work suggests that DMSP likely has an important role in heterotrophic bacteria ecology than previously appreciated.
Dimethylsulfoniopropionate
Organosulfur compounds
Cite
Citations (13)
Osmolyte
Cite
Citations (87)
Osmolyte
Dimethylsulfoniopropionate
Denaturation (fissile materials)
Cryoprotectant
Cite
Citations (80)
We have studied whether two common osmolytes - proline (Pro) and glycine betaine (GB) - accumulate in plants of different Plantago species in response to salt and water stress, which would suggest that these compatible solutes and 'osmoprotectants' fulfil a functional role of in the plants' stress tolerance mechanisms. Plants of P. coronopus, P. major, P. crassifolia and P. lagopus were treated with increasing NaCl concentrations or subjected to water stress, under controlled conditions in the greenhouse. GB and Pro contents in control, non-stressed plants were relatively low and, in most cases, did not change, or increased only moderately when the plants were maintained without water or were grown in the presence of up to 400 mM NaCl, for four weeks. However, higher salt concentrations (450 - 600 mM NaCl), which these taxa never encounter in their natural habitats, induced a significant accumulation of Pro in all species but P. major, the most salt-sensitive one. These data indicate that GB and Pro do not act as functional osmolytes in Plantago species, and do not contribute to osmotic adjustment under natural conditions; however, these plants have the potential to activate Pro-mediated mechanisms of salt tolerance at very high, artificial salinity levels.
Osmolyte
Betaine
Plantago
Plantaginaceae
Ectoine
Cite
Citations (1)
ABSTRACT Osmolyte accumulation and release can protect cells from abiotic stresses. In Escherichia coli , known mechanisms mediate osmotic stress-induced accumulation of K + glutamate, trehalose, or zwitterions like glycine betaine. Previous observations suggested that additional osmolyte accumulation mechanisms (OAMs) exist and their impacts may be abiotic stress specific. Derivatives of the uropathogenic strain CFT073 and the laboratory strain MG1655 lacking known OAMs were created. CFT073 grew without osmoprotectants in minimal medium with up to 0.9 M NaCl. CFT073 and its OAM-deficient derivative grew equally well in high- and low-osmolality urine pools. Urine-grown bacteria did not accumulate large amounts of known or novel osmolytes. Thus, CFT073 showed unusual osmotolerance and did not require osmolyte accumulation to grow in urine. Yeast extract and brain heart infusion stimulated growth of the OAM-deficient MG1655 derivative at high salinity. Neither known nor putative osmoprotectants did so. Glutamate and glutamine accumulated after growth with either organic mixture, and no novel osmolytes were detected. MG1655 derivatives retaining individual OAMs were created. Their abilities to mediate osmoprotection were compared at 15°C, 37°C without or with urea, and 42°C. Stress protection was not OAM specific, and variations in osmoprotectant effectiveness were similar under all conditions. Glycine betaine and dimethylsulfoniopropionate (DMSP) were the most effective. Trimethylamine- N -oxide (TMAO) was a weak osmoprotectant and a particularly effective urea protectant. The effectiveness of glycine betaine, TMAO, and proline as osmoprotectants correlated with their preferential exclusion from protein surfaces, not with their propensity to prevent protein denaturation. Thus, their effectiveness as stress protectants correlated with their ability to rehydrate the cytoplasm.
Osmolyte
Betaine
Dimethylsulfoniopropionate
Osmotic shock
Ectoine
Cite
Citations (40)
Summary: The response of Enterococcus faecalis ATCC 19433 to salt stress has been characterized previously in complex media. In this report, it has been demonstrated that this bacterium actively accumulates the osmoprotectant glycine betaine (GB) from salt-enriched complex medium BHI. To further understand the specific effects of GB and other osmoprotective compounds in salt adaptation and salt-induced cross-tolerance to lethal challenges, a chemically defined medium lacking putative osmoprotectants was used. In this medium, bacterial growth was significantly reduced by increasing concentrations of NaCl. At 0·75 M NaCl, 90% inhibition of the growth rate was observed; GB and its structural analogues restored growth to the non-salt-stressed level. In contrast, proline, pipecolate and ectoine did not allow growth recovery of stressed cells. Kinetic studies showed that the uptake of betaines shows strong structural specificity and occurs through a salt-stress-inducible high-affinity porter [K m = 3·3 μM; V max = 130 nmol min-1 (mg protein)-1; the uptake activity increased 400-fold in the presence of 0·5 M NaCl], Moreover, GB and its analogues were accumulated as non-metabolizable cytosolic osmolytes and reached intracellular levels ranging from 1·3 to 1·5 μmol (mg protein)-1. In contrast to the beneficial effect of GB on the growth of salt-stressed cultures of E. faecalis, its accumulation inhibits the salt-induced cross-tolerance to a heterologous lethal challenge. Indeed, pretreatment of bacterial cells with 0·5 M NaCl induced resistance to 0.3% bile salts (survival of adapted cells increased by a factor of 6800). The presence of GB in the adaptation medium reduced the acquisition of bile salts resistance 680-fold. The synthesis of 11 of the 13 proteins induced during salt adaptation was significantly reduced in the presence of GB. These results raise questions about the actual beneficial effect of GB in natural environments where bacteria are often subjected to various stresses.
Osmolyte
Betaine
Ectoine
Enterococcus faecalis
Growth medium
Cite
Citations (51)
Osmolyte
Turgor pressure
Osmoregulation
Osmotic shock
Ectoine
Osmotic pressure
MreB
Cite
Citations (1,064)