Ion transport and osmotic adjustment in plants and bacteria

2011 ◽  
Vol 2 (5) ◽  
pp. 407-419 ◽  
Author(s):  
Sergey Shabala ◽  
Lana Shabala
Keyword(s):  
Osmotic Adjustment ◽  
De Novo ◽  
Compatible Solutes ◽  
Inorganic Ions ◽  
Growth Conditions ◽  
High Yield ◽  
Organic Osmolytes ◽  
Ros Scavenging ◽  
Membrane Transport Proteins ◽  
Cell Turgor

AbstractPlants and bacteria respond to hyperosmotic stress by an increase in intracellular osmolality, adjusting their cell turgor to altered growth conditions. This can be achieved either by increased uptake orde novosynthesis of a variety of organic osmolytes (so-called ‘compatible solutes’), or by controlling fluxes of ions across cellular membranes. The relative contributions of each of these mechanisms have been debated in literature for many years and remain unresolved. This paper summarises all the arguments and reopens a discussion on the efficiency and strategies of osmotic adjustment in plants and bacteria. We show that the bulk of osmotic adjustment in both plants and bacteria is achieved by increased accumulation of inorganic osmolytes such as K+, Na+and Cl-. This is applicable to both halophyte and glycophyte species. At the same time,de novosynthesis of compatible solutes is an energetically expensive and slow option and can be used only for the fine adjustment of the cell osmotic potential. The most likely role the organic osmolytes play in osmotic adjustment is in osmoprotection of key membrane transport proteins and reactive oxygen species (ROS) scavenging. The specific mechanisms by which compatible solutes regulate activity of ion transporters remain elusive and require more thorough investigation. It is concluded that creating transgenic species with increased levels of organic osmolytes by itself is counterproductive due to high yield penalties; all these attempts should be complemented by a concurrent increase in the accumulation of inorganic ions directly used for osmotic adjustment.

scholarly journals Glycine Betaine Transport in the Obligate Halophilic Archaeon Methanohalophilus portucalensis

2000 ◽  
Vol 182 (17) ◽  
pp. 5020-5024 ◽  
Author(s):  
Mei-Chin Lai ◽  
Tong-Yung Hong ◽  
Robert P. Gunsalus
Keyword(s):  
Transport System ◽  
Glycine Betaine ◽  
De Novo ◽  
Compatible Solutes ◽  
Growth Conditions ◽  
The Other ◽  
De Novo Synthesis ◽  
Atpase Inhibitor ◽  
High Affinity ◽  
Solute Uptake

ABSTRACT Transport of the osmoprotectant glycine betaine was investigated using the glycine betaine-synthesizing microbe Methanohalophilus portucalensis (strain FDF1), since solute uptake for this class of obligate halophilic methanogenic Archaea has not been examined. Betaine uptake followed a Michaelis-Menten relationship, with an observed Kt of 23 μM and aV max of 8 nmol per min per mg of protein. The transport system was highly specific for betaine: choline, proline, and dimethylglycine did not significantly compete for [14C]betaine uptake. The proton-conducting uncoupler 2,4-dinitrophenol and the ATPase inhibitorN,N-dicyclohexylcarbodiimide both inhibited glycine betaine uptake. Growth of cells in the presence of 500 μM betaine resulted in faster cell growth due to the suppression of the de novo synthesis of the other compatible solutes, α-glutamate, β-glutamine, and N ɛ-acetyl-β-lysine. These investigations demonstrate that this model halophilic methanogen,M. portucalensis strain FDF1, possesses a high-affinity and highly specific betaine transport system that allows it to accumulate this osmoprotectant from the environment in lieu of synthesizing this or other osmoprotectants under high-salt growth conditions.

scholarly journals Osmotically Regulated Synthesis of the Compatible Solute Ectoine in Bacillus pasteurii and Related Bacillus spp

2002 ◽  
Vol 68 (2) ◽  
pp. 772-783 ◽  
Author(s):  
Anne U. Kuhlmann ◽  
Erhard Bremer
Keyword(s):  
Growth Medium ◽  
High Performance ◽  
Hplc Analysis ◽  
De Novo ◽  
Compatible Solutes ◽  
Growth Conditions ◽  
Compatible Solute ◽  
Resonance Spectroscopy ◽  
Bacillus Pasteurii ◽  
Diaminobutyric Acid

ABSTRACT By using natural-abundance 13C-nuclear magnetic resonance spectroscopy and high-performance liquid chromatography (HPLC) analysis we have investigated the types of compatible solutes that are synthesized de novo in a variety of Bacillus species under high-osmolality growth conditions. Five different patterns of compatible solute production were found among the 13 Bacillus species we studied. Bacillus subtilis, B. licheniformis, and B. megaterium produced proline; B. cereus, B. circulans, B. thuringiensis, Paenibacillus polymyxa, and Aneurinibacillus aneurinilyticus synthesized glutamate; B. alcalophilus, B. psychrophilus, and B. pasteurii synthesized ectoine; and Salibacillus (formerly Bacillus) salexigens produced both ectoine and hydroxyectoine, whereas Virgibacillus (formerly Bacillus) pantothenticus synthesized both ectoine and proline. Hence, the ability to produce the tetrahydropyrimidine ectoine under hyperosmotic growth conditions is widespread within the genus Bacillus and closely related taxa. To study ectoine biosynthesis within the group of Bacillus species in greater detail, we focused on B. pasteurii. We cloned and sequenced its ectoine biosynthetic genes (ectABC). The ectABC genes encode the diaminobutyric acid acetyltransferase (EctA), the diaminobutyric acid aminotransferase (EctB), and the ectoine synthase (EctC). Together these proteins constitute the ectoine biosynthetic pathway, and their heterologous expression in B. subtilis led to the production of ectoine. Northern blot analysis demonstrated that the ectABC genes are genetically organized as an operon whose expression is strongly enhanced when the osmolality of the growth medium is raised. Primer extension analysis allowed us to pinpoint the osmoregulated promoter of the B. pasteurii ectABC gene cluster. HPLC analysis of osmotically challenged B. pasteurii cells revealed that ectoine production within this bacterium is finely tuned and closely correlated with the osmolality of the growth medium. These observations together with the osmotic control of ectABC transcription suggest that the de novo synthesis of ectoine is an important facet in the cellular adaptation of B. pasteurii to high-osmolarity surroundings.

Osmotic adjustment and plant adaptation to environmental changes related to drought and salinity

2010 ◽  
Vol 18 (NA) ◽  
pp. 309-319 ◽  
Author(s):  
Hui Chen ◽  
Jian-Guo Jiang
Keyword(s):  
Osmotic Adjustment ◽  
Molecular Mechanisms ◽  
Environmental Changes ◽  
Genetic Manipulation ◽  
Compatible Solutes ◽  
Inorganic Ions ◽  
Research Field ◽  
Transport Processes ◽  
Organic Solutes ◽  
Extracellular Ions

The salinization and water deficit of soil are widespread environmental problems in limiting plant survival, growth, and productivity. However, some plants could adopt some strategies to resist salinity and drought stresses. Among these strategies, the mechanism of osmotic adjustment could help plants and algae to avoid ion toxicity and maintain water uptake in both stresses by accumulating large quantities of osmolytes. Two types of osmolytes, organic solutes and inorganic ions, play a key role in osmotic adjustment. Different osmolytes and their osmotic adjustment actions are different according to their distribution in different plants. Organic solutes, known as compatible solutes, include amino acids, glycerol, sugars, and other low molecular weight metabolites, serve a function in cells to lower or balance the osmotic potential of intracellular and extracellular ions in resistance to osmotic stresses. Inorganic ions for osmotic adjustment are mainly Na+, K+, Ca2+, and Cl–. Inorganic ions make great contribution in osmotic adjustment by ion transport processes with related ion antiporters and ion channels. The aim of this review is to integrate recent data on the mechanisms of osmotic adjustment by osmolytes in plants and algae, and to illustrate the variety of related molecular mechanisms, to introduce new concepts and techniques into this research field. Genetic manipulation including the application of transgenic techniques in plants provides promising strategies to elevate the tolerance capability of plants under osmotic stress conditions.

scholarly journals Synthesis, Release, and Recapture of Compatible Solute Proline by Osmotically Stressed Bacillus subtilis Cells

2012 ◽  
Vol 78 (16) ◽  
pp. 5753-5762 ◽  
Author(s):  
Tamara Hoffmann ◽  
Carsten von Blohn ◽  
Agnieszka Stanek ◽  
Susanne Moses ◽  
Helena Barzantny ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
High Salinity ◽  
De Novo ◽  
Compatible Solutes ◽  
Growth Conditions ◽  
Compatible Solute ◽  
Content Type ◽  
Cellular Defense ◽  
Stressed Cells ◽  
External Salinity

ABSTRACTBacillus subtilissynthesizes large amounts of the compatible solute proline as a cellular defense against high osmolarity to ensure a physiologically appropriate level of hydration of the cytoplasm and turgor. It also imports proline for this purpose via the osmotically inducible OpuE transport system. Unexpectedly, anopuEmutant was at a strong growth disadvantage in high-salinity minimal media lacking proline. Appreciable amounts of proline were detected in the culture supernatant of theopuEmutant strain, and they rose concomitantly with increases in the external salinity. We found that the intracellular proline pool of severely salinity-stressed cells of theopuEmutant was considerably lower than that of itsopuE+parent strain. This loss of proline into the medium and the resulting decrease in the intracellular proline content provide a rational explanation for the observed salt-sensitive growth phenotype of cells lacking OpuE. None of the known MscL- and MscS-type mechanosensitive channels ofB. subtilisparticipated in the release of proline under permanently imposed high-salinity growth conditions. The data reported here show that the OpuE transporter not only possesses the previously reported role for the scavenging of exogenously provided proline as an osmoprotectant but also functions as a physiologically highly important recapturing device for proline that is synthesizedde novoand subsequently released by salt-stressedB. subtiliscells. The wider implications of our findings for the retention of compatible solutes by osmotically challenged microorganisms and the roles of uptake systems for compatible solutes are considered.

scholarly journals Salmonella typhimurium synthesizes cobalamin (vitamin B12) de novo under anaerobic growth conditions.

1984 ◽  
Vol 159 (1) ◽  
pp. 206-213 ◽  
Author(s):  
R M Jeter ◽  
B M Olivera ◽  
J R Roth
Keyword(s):  
Vitamin B12 ◽  
Salmonella Typhimurium ◽  
De Novo ◽  
Growth Conditions ◽  
Anaerobic Growth

scholarly journals Efficient production of vindoline from tabersonine by metabolically engineered Saccharomyces cerevisiae

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Tengfei Liu ◽  
Ying Huang ◽  
Lihong Jiang ◽  
Chang Dong ◽  
Yuanwei Gou ◽  
...  
Keyword(s):  
Cytochrome P450 ◽  
De Novo ◽  
Indole Alkaloid ◽  
Functional Expression ◽  
High Yield ◽  
Efficient Production ◽  
Cytochrome P450 Enzymes ◽  
Copy Numbers ◽  
Yield Production ◽  
Engineered Saccharomyces Cerevisiae

AbstractVindoline is a plant derived monoterpene indole alkaloid (MIA) with potential therapeutic applications and more importantly serves as the precursor to vinblastine and vincristine. To obtain a yeast strain for high yield production of vindoline from tabersonine, multiple metabolic engineering strategies were employed via the CRISPR/Cas9 mediated multiplex genome integration technology in the present study. Through increasing and tuning the copy numbers of the pathway genes, pairing cytochrome P450 enzymes (CYPs) with appropriate cytochrome P450 reductases (CPRs), engineering the microenvironment for functional expression of CYPs, enhancing cofactor supply, and optimizing fermentation conditions, the production of vindoline was increased to a final titer as high as ∼16.5 mg/L, which is more than 3,800,000-fold higher than the parent strain and the highest tabersonine to vindoline conversion yield ever reported. This work represents a key step of the engineering efforts to establish de novo biosynthetic pathways for vindoline, vinblastine, and vincristine.

scholarly journals Overexpression of WAX INDUCER1/SHINE1 Gene Enhances Wax Accumulation under Osmotic Stress and Oil Synthesis in Brassica napus

2019 ◽  
Vol 20 (18) ◽  
pp. 4435 ◽  
Author(s):  
Ning Liu ◽  
Jie Chen ◽  
Tiehu Wang ◽  
Qing Li ◽  
Pengpeng Cui ◽  
...  
Keyword(s):  
Salt Stress ◽  
Brassica Napus ◽  
De Novo ◽  
Normal Growth ◽  
Acid Synthesis ◽  
Growth Conditions ◽  
Lipid Profiling ◽  
Intracellular Lipids ◽  
Oil Synthesis ◽  
Genes Encoding

WAX INDUCER1/SHINE1 (WIN1) belongs to the AP2/EREBP transcription factor family and plays an important role in wax and cutin accumulation in plants. Here we show that BnWIN1 from Brassica napus (Bn) has dual functions in wax accumulation and oil synthesis. Overexpression (OE) of BnWIN1 led to enhanced wax accumulation and promoted growth without adverse effects on oil synthesis under salt stress conditions. Lipid profiling revealed that BnWIN1-OE plants accumulated more waxes with elevated C29-alkanes, C31-alkanes, C28-alcohol, and C29-alcohol relative to wild type (WT) under salt stress. Moreover, overexpression of BnWIN1 also increased seed oil content under normal growth conditions. BnWIN1 directly bound to the promoter region of genes encoding biotin carboxyl carrier protein 1 (BCCP1), glycerol-3-phosphate acyltransferase 9 (GPAT9), lysophosphatidic acid acyltransferase 5 (LPAT5), and diacylglycerol acyltransferase 2 (DGAT2) involved in the lipid anabolic process. Overexpression of BnWIN1 resulted in upregulated expression of numerous genes involved in de novo fatty acid synthesis, wax accumulation, and oil production. The results suggest that BnWIN1 is a transcriptional activator to regulate the biosynthesis of both extracellular and intracellular lipids.

scholarly journals Yield and Quality Characteristics of Brassica Microgreens as Affected by the NH4:NO3 Molar Ratio and Strength of the Nutrient Solution

Foods ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 677 ◽  
Author(s):  
Onofrio Davide Palmitessa ◽  
Massimiliano Renna ◽  
Pasquale Crupi ◽  
Angelo Lovece ◽  
Filomena Corbo ◽  
...  
Keyword(s):  
Nutrient Solution ◽  
Inorganic Ions ◽  
Molar Ratio ◽  
High Yield ◽  
Nitrate Content ◽  
Carotene Content ◽  
Molar Ratios ◽  
Half Strength ◽  
Nutrient Solutions ◽  
Β Carotene

Microgreens are gaining more and more interest, but little information is available on the effects of the chemical composition of the nutrient solution on the microgreen yield. In this study, three Brassica genotypes (B. oleracea var. italica, B. oleracea var. botrytis, and Brassica rapa L. subsp. sylvestris L. Janch. var. esculenta Hort) were fertigated with three modified strength Hoagland nutrient solutions (1/2, 1/4, and 1/8 strength) or with three modified half-strength Hoagland nutrient solutions with three different NH4:NO3 molar ratios (5:95, 15:85, and 25:75). Microgreen yields and content of inorganic ions, dietary fiber, proteins, α-tocopherol, and β-carotene were evaluated. Micro cauliflower showed the highest yield, as well as a higher content of mineral elements and α-tocopherol (10.4 mg 100 g−1 fresh weight (FW)) than other genotypes. The use of nutrient solution at half strength gave both a high yield (0.23 g cm−2) and a desirable seedling height. By changing the NH4:NO3 molar ratio in the nutrient solution, no differences were found on yield and growing parameters, although the highest β-carotene content (6.3 mg 100 g−1 FW) was found by using a NH4:NO3 molar ratio of 25:75. The lowest nitrate content (on average 6.8 g 100 g−1 dry weight) was found in micro broccoli and micro broccoli raab by using a nutrient solution with NH4:NO3 molar ratios of 25:75 and 5:95, respectively. Micro cauliflower fertigated with a NH4:NO3 molar ratio of 25:75 showed the highest dry matter (9.8 g 100 g−1 FW) and protein content (4.2 g 100 g−1 FW).

Regulation of the Synthesis of Ribulose-l,5-bisphosphate Carboxylase and Its Subunits in the Flagellate Chlorogonium elongatum. II. Coordinated Synthesis of the Large and Small Subunits

1981 ◽  
Vol 36 (11-12) ◽  
pp. 942-950 ◽  
Author(s):  
Peter Westhoff ◽  
Kurt Zimmermann ◽  
Frank Boege ◽  
Klaus Zetsche
Keyword(s):  
Rna Synthesis ◽  
De Novo ◽  
Fold Increase ◽  
Growth Conditions ◽  
Autotrophic Growth ◽  
De Novo Synthesis ◽  
Bisphosphate Carboxylase ◽  
Unicellular Green Alga ◽  
Protein And Rna Synthesis ◽  
Ribulosebisphosphate Carboxylase

Abstract Transfer of heterotrophically grown cells of the unicellular green alga Chlorogonium elongatum to autotrophic growth conditions causes a 10 -15 fold increase in the amount of the chloroplastic enzyme ribulose-1,5-bisphosphate carboxylase. This increase was found to be due to de novo synthesis. The relative proportions of large and small subunits of the enzyme do not change. Their ratio is close to 3.4, the proportions in weight of the two subunits in the holoenzyme. Continous labelling with [35S]sulfate reveals that the ratios of incorporation into large and small subunits are essentially the same in autotrophic and heterotrophic cells. Pulse-chase experiments show that the subunits are degraded synchronously. The coordinated subunit synthesis cannot be uncoupled using inhibitors of protein and RNA synthesis or high temperature of cultivation of the alga. The results suggests a very tightly coordinated synthesis of the large and small subunits of ribulosebisphosphate carboxylase.

Physiological, anatomical and antioxidant responses to salinity in the Mediterranean pastoral grass plant Stipa lagascae

2017 ◽  
Vol 68 (9) ◽  
pp. 872 ◽  
Author(s):  
Raoudha Abdellaoui ◽  
Fayçal Boughalleb ◽  
Zohra Chebil ◽  
Maher Mahmoudi ◽  
Azaiez Ouled Belgacem
Keyword(s):  
Glutathione Reductase ◽  
Ascorbate Peroxidase ◽  
Osmotic Adjustment ◽  
Perennial Grass ◽  
Soluble Sugars ◽  
Ros Scavenging ◽  
Total Soluble Sugars ◽  
Chlorophyll Pigments ◽  
Moderate Salinity ◽  
Stipa Lagascae

Soil and water salinity is a major environmental problem in the dry Mediterranean regions, affecting rangeland production. This study investigated the effects of salinity on the wild perennial grass (Poaceae) species Stipa lagascae R. & Sch., a potential forage plant that could be used to rehabilitate degraded rangelands in dry areas. In a laboratory, 3-month-old S. lagascae seedlings were subjected to increasing salt treatments (0–400 mm NaCl) for 45 days. Physiological and biochemical parameters such as leaf water potential (Ψw), leaf relative water content (RWC), proline, total soluble sugars, Na+, K+ and Ca2+ contents, and catalase, ascorbate peroxidase and glutathione reductase activities were measured. Total soluble sugars and proline concentrations increased and Ψw and RWC decreased with increasing salt concentrations. Lower salt concentrations induced a non-significant degradation of chlorophyll pigments. Shoot Na+ content increased with a salinity level, whereas shoot K+ and Ca2+ concentrations decreased and the K+ : Na+ ratio was lower. The salinity threshold, above which S. lagascae showed signs of damage, occurred at 300 mm. Plants have evolved reactive oxygen species (ROS) scavenging enzymes including catalase, ascorbate peroxidase and glutathione reductase, which provide cells with an efficient mechanism to neutralise ROS. The tolerance strategies of S. lagascae to moderate salinity seem to include osmotic adjustment through total soluble sugars and proline accumulation, and highly inducible antioxidative defence. Further investigations are necessary to study the effect of salt stress on distribution of ions (Na+, K+, Ca2+, Mg2+, Cl–, NO3–, SO42–) and osmotic adjustment. Photosynthesis and water-use efficiency parameters could be also useful tools.

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