scholarly journals Osmotic Adaptation and Compatible Solute Biosynthesis of Phototrophic Bacteria as Revealed from Genome Analyses

2020 ◽  
Vol 9 (1) ◽  
pp. 46
Author(s):  
Johannes F. Imhoff ◽  
Tanja Rahn ◽  
Sven Künzel ◽  
Alexander Keller ◽  
Sven C. Neulinger
Keyword(s):  
Glycine Betaine ◽  
Compatible Solutes ◽  
Compatible Solute ◽  
Phototrophic Bacteria ◽  
Transport Systems ◽  
Phylogenetic Groups ◽  
Osmotic Adaptation ◽  
Cell Structures ◽  
Freshwater Bacteria ◽  
Genome Analyses

Osmotic adaptation and accumulation of compatible solutes is a key process for life at high osmotic pressure and elevated salt concentrations. Most important solutes that can protect cell structures and metabolic processes at high salt concentrations are glycine betaine and ectoine. The genome analysis of more than 130 phototrophic bacteria shows that biosynthesis of glycine betaine is common among marine and halophilic phototrophic Proteobacteria and their chemotrophic relatives, as well as in representatives of Pirellulaceae and Actinobacteria, but are also found in halophilic Cyanobacteria and Chloroherpeton thalassium. This ability correlates well with the successful toleration of extreme salt concentrations. Freshwater bacteria in general lack the possibilities to synthesize and often also to take up these compounds. The biosynthesis of ectoine is found in the phylogenetic lines of phototrophic Alpha- and Gammaproteobacteria, most prominent in the Halorhodospira species and a number of Rhodobacteraceae. It is also common among Streptomycetes and Bacilli. The phylogeny of glycine-sarcosine methyltransferase (GMT) and diaminobutyrate-pyruvate aminotransferase (EctB) sequences correlate well with otherwise established phylogenetic groups. Most significantly, GMT sequences of cyanobacteria form two major phylogenetic branches and the branch of Halorhodospira species is distinct from all other Ectothiorhodospiraceae. A variety of transport systems for osmolytes are present in the studied bacteria.

Humectant Permeability Influences Growth and Compatible Solute Uptake by Staphylococcus aureus Subjected to Osmotic Stress

2002 ◽  
Vol 65 (6) ◽  
pp. 1008-1015 ◽  
Author(s):  
ODDUR VILHELMSSON ◽  
KAREN J. MILLER
Keyword(s):  
Staphylococcus Aureus ◽  
Sodium Chloride ◽  
Water Activity ◽  
Glycine Betaine ◽  
Compatible Solutes ◽  
Foodborne Pathogen ◽  
Compatible Solute ◽  
Solute Uptake ◽  
Stressed Cells ◽  
Carnitine Uptake

The effects of different humectants (sodium chloride, sucrose, and glycerol) on the growth of and compatible solute (glycine betaine, proline, and carnitine) uptake by the osmotolerant foodborne pathogen Staphylococcus aureus were investigated. While growth in the presence of the impermeant humectants sodium chloride and sucrose induced the accumulation of proline and glycine betaine by cells, growth in the presence of the permeant humectant glycerol did not. When compatible solutes were omitted from low-water-activity media, growth was very poor in the presence of impermeant humectants. In contrast, the addition of compatible solutes had essentially no effect on growth when cells were grown in low-water-activity media containing glycerol as the humectant. Carnitine was found to accumulate to high intracellular levels in osmotically stressed cells when proline and glycine betaine were absent, making it a potentially important compatible solute for this organism.

scholarly journals Role of σB in Regulating the Compatible Solute Uptake Systems of Listeria monocytogenes: Osmotic Induction of opuC Is σB Dependent

2003 ◽  
Vol 69 (4) ◽  
pp. 2015-2022 ◽  
Author(s):  
Katy R. Fraser ◽  
David Sue ◽  
Martin Wiedmann ◽  
Kathryn Boor ◽  
Conor P. O'Byrne
Keyword(s):  
Listeria Monocytogenes ◽  
Solute Transport ◽  
Compatible Solutes ◽  
Strain Analysis ◽  
Compatible Solute ◽  
Transport Systems ◽  
Carnitine Transporter ◽  
Solute Uptake ◽  
Carnitine Transport

ABSTRACT The regulation of the compatible solute transport systems in Listeria monocytogenes by the stress-inducible sigma factor σB was investigated. Using wild-type strain 10403S and an otherwise isogenic strain carrying an in-frame deletion in sigB, we have examined the role of σB in regulating the ability of cells to utilize betaine and carnitine during growth under conditions of hyperosmotic stress. Cells lacking σB were defective for the utilization of carnitine but retained the ability to utilize betaine as an osmoprotectant. When compatible solute transport studies were performed, the initial rates of uptake of both betaine and carnitine were found to be reduced in the sigB mutant; carnitine transport was almost abolished, whereas betaine transport was reduced to approximately 50% of that of the parent strain. Analysis of the cytoplasmic pools of compatible solutes during balanced growth revealed that both carnitine and betaine steady-state pools were reduced in the sigB mutant. Transcriptional reporter fusions to the opuC (which encodes an ABC carnitine transporter) and betL (which encodes an a secondary betaine transporter) operons were generated by using a promoterless copy of the gus gene from Escherichia coli. Measurement of β-glucuronidase activities directed by opuC-gus and betL-gus revealed that transcription of opuC is largely σB dependent, consistent with the existence of a potential σB consensus promoter motif upstream from opuCA. The transcription of betL was found to be sigB independent. Reverse transcriptase PCR experiments confirmed these data and indicated that the transcription of all three known compatible solute uptake systems (opuC, betL, and gbu), as well as a gene that is predicted to encode a compatible solute transporter subunit (lmo1421) is induced in response to elevated osmolarity. The osmotic induction of opuCA and lmo1421 was found to be strongly σB dependent. Together these observations suggest that σB plays a major role in the regulation of carnitine utilization by L. monocytogenes but is not essential for betaine utilization by this pathogen.

scholarly journals Identification of a Salt-Induced Primary Transporter for Glycine Betaine in the Methanogen Methanosarcina mazei Gö1

2002 ◽  
Vol 68 (5) ◽  
pp. 2133-2139 ◽  
Author(s):  
M. Roeßler ◽  
K. Pflüger ◽  
H. Flach ◽  
T. Lienard ◽  
G. Gottschalk ◽  
...  
Keyword(s):  
Glycine Betaine ◽  
Northern Blot Analysis ◽  
Compatible Solutes ◽  
Gene Organization ◽  
Compatible Solute ◽  
Salt Adaptation ◽  
Methanosarcina Mazei ◽  
Transport Studies ◽  
Uptake Activity ◽  
Transport Device

ABSTRACT The salt adaptation of the methanogenic archaeon Methanosarcina mazei Gö1 was studied at the physiological and molecular levels. The freshwater organism M. mazei Gö1 was able to adapt to salt concentrations up to 1 M, and the addition of the compatible solute glycine betaine to the growth medium facilitated adaptation to higher salt concentrations. Transport studies with cell suspensions revealed a salt-induced glycine betaine uptake activity in M. mazei Gö1, and inhibitor studies argue for a primary transport device. Analysis of the genome of M. mazei Gö1 identified a homolog of known primary glycine betaine transporters. This gene cluster was designated Ota (osmoprotectant transporter A). Its sequence and gene organization are very similar to those of the glycine betaine transporter OpuA of Bacillus subtilis. Northern blot analysis of otaC revealed a salt-dependent transcription of this gene. Ota is the first identified salt-induced transporter for compatible solutes in Archaea.

scholarly journals CosR is a repressor of compatible solute biosynthesis and transporter systems

2019 ◽  
Author(s):  
Gwendolyn J. Gregory ◽  
Daniel P. Morreale ◽  
E. Fidelma Boyd
Keyword(s):  
Glycine Betaine ◽  
Vibrio Parahaemolyticus ◽  
Turgor Pressure ◽  
Regulatory Region ◽  
Compatible Solutes ◽  
Compatible Solute ◽  
Negative Regulator ◽  
Low Salinity ◽  
Transporter Systems ◽  
Ectoine Biosynthesis

AbstractBacteria accumulate small, organic compounds, called compatible solutes, via uptake from the environment or biosynthesis from available precursors to maintain the turgor pressure of the cell in response to osmotic stress. Vibrio parahaemolyticus has biosynthesis pathways for the compatible solutes ectoine (ectABCasp_ect) and glycine betaine (betIBAproXWV), four betaine-carnitine-choline transporters (bcct1-bcct4) and a second ProU transporter (proVWX). Most of these systems are induced in high salt. CosR, a MarR-type regulator, which is divergently transcribed from bcct3, was previously shown to be a direct repressor of ectABCasp_ect in Vibrio species. In this study, we investigated the role of CosR in glycine betaine biosynthesis and compatible solute transporter gene regulation. Expression analyses demonstrated that betIBAproXWV, bcct1, bcct3, and proVWX are repressed in low salinity. Examination of an in-frame cosR deletion mutant shows induced expression of these systems in the mutant at low salinity compared to wild-type. DNA binding assays demonstrate that purified CosR binds directly to the regulatory region of each system. In Escherichia coli GFP reporter assays, we demonstrate that CosR directly represses transcription of betIBAproXWV, bcct3, and proVWX. Similar to V. harveyi, we show betIBAproXWV is positively regulated by the LuxR homolog OpaR. Bioinformatics analysis demonstrates that CosR is widespread within the genus, present in over 50 species. In several species, the cosR homolog was clustered with the betIBAproXWV operon, which again suggests the importance of this regulator in glycine betaine biosynthesis. Incidentally, in four Aliivibrio species that contain ectoine biosynthesis genes, we identified another MarR-type regulator, ectR, clustered with these genes, which suggests the presence of a novel ectoine regulator. Homologs of EctR in this genomic context were present in A. fischeri, A. finisterrensis, A. sifiae and A. wodanis.ImportanceVibrio parahaemolyticus can accumulate compatible solutes via biosynthesis and transport, which allow the cell to survive in high salinity conditions. There is little need for compatible solutes under low salinity conditions, and biosynthesis and transporter systems are repressed. However, the mechanism of this repression is not fully elucidated. CosR plays a major role in the repression of multiple compatible solute systems in V. parahaemolyticus as a direct negative regulator of ectoine and glycine betaine biosynthesis systems and four transporters. Homology analysis suggests that CosR functions in this manner in many other Vibrio species. In Aliivibrio species, we identified a new MarR family regulator EctR that clusters with the ectoine biosynthesis genes.

scholarly journals Investigations of Dimethylglycine, Glycine Betaine, and Ectoine Uptake by a Betaine-Carnitine-Choline Transporter Family Transporter with Diverse Substrate Specificity in Vibrio Species

2020 ◽  
Vol 202 (24) ◽  
Author(s):  
Gwendolyn J. Gregory ◽  
Anirudha Dutta ◽  
Vijay Parashar ◽  
E. Fidelma Boyd
Keyword(s):  
Amino Acid ◽  
Glycine Betaine ◽  
Vibrio Parahaemolyticus ◽  
Compatible Solutes ◽  
Binding Pocket ◽  
Compatible Solute ◽  
Amino Acid Residues ◽  
Choline Transporter ◽  
Content Type ◽  
Highly Effective

ABSTRACT Fluctuations in osmolarity are one of the most prevalent stresses to which bacteria must adapt, both hypo- and hyperosmotic conditions. Most bacteria cope with high osmolarity by accumulating compatible solutes (osmolytes) in the cytoplasm to maintain the turgor pressure of the cell. Vibrio parahaemolyticus, a halophile, utilizes at least six compatible solute transporters for the uptake of osmolytes: two ABC family ProU transporters and four betaine-carnitine-choline transporter (BCCT) family transporters. The full range of compatible solutes transported by this species has yet to be determined. Using an osmolyte phenotypic microarray plate for growth analyses, we expanded the known osmolytes used by V. parahaemolyticus to include N,N-dimethylglycine (DMG), among others. Growth pattern analysis of four triple-bccT mutants, possessing only one functional BCCT, indicated that BccT1 (VP1456), BccT2 (VP1723), and BccT3 (VP1905) transported DMG. BccT1 was unusual in that it could take up both compounds with methylated head groups (glycine betaine [GB], choline, and DMG) and cyclic compounds (ectoine and proline). Bioinformatics analysis identified the four coordinating amino acid residues for GB in the BccT1 protein. In silico modeling analysis demonstrated that GB, DMG, and ectoine docked in the same binding pocket in BccT1. Using site-directed mutagenesis, we showed that a strain with all four residues mutated resulted in the loss of uptake of GB, DMG, and ectoine. We showed that three of the four residues were essential for ectoine uptake, whereas only one of the residues was important for GB uptake. Overall, we have demonstrated that DMG is a highly effective compatible solute for Vibrio species and have elucidated the amino acid residues in BccT1 that are important for the coordination of GB, DMG, and ectoine transport. IMPORTANCE Vibrio parahaemolyticus possesses at least six osmolyte transporters, which allow the bacterium to adapt to high-salinity conditions. In this study, we identified several additional osmolytes that were utilized by V. parahaemolyticus. We demonstrated that the compound DMG, which is present in the marine environment, was a highly effective osmolyte for Vibrio species. We determined that DMG is transported via BCCT family carriers, which have not been shown previously to take up this compound. BccT1 was a carrier for GB, DMG, and ectoine, and we identified the amino acid residues essential for the coordination of these compounds. The data suggest that for BccT1, GB is more easily accommodated than ectoine in the transporter binding pocket.

scholarly journals Compatible-Solute-Supported Periplasmic Expression of Functional Recombinant Proteins under Stress Conditions

2000 ◽  
Vol 66 (4) ◽  
pp. 1572-1579 ◽  
Author(s):  
S. Barth ◽  
M. Huhn ◽  
B. Matthey ◽  
A. Klimka ◽  
E. A. Galinski ◽  
...  
Keyword(s):  
Osmotic Stress ◽  
Recombinant Proteins ◽  
Glycine Betaine ◽  
Metal Ion ◽  
Halophilic Bacteria ◽  
Compatible Solutes ◽  
Compatible Solute ◽  
Size Exclusion ◽  
High Yield ◽  
High Concentrations

ABSTRACT The standard method of producing recombinant proteins such as immunotoxins (rITs) in large quantities is to transform gram-negative bacteria and subsequently recover the desired protein from inclusion bodies by intensive de- and renaturing procedures. The major disadvantage of this technique is the low yield of active protein. Here we report the development of a novel strategy for the expression of functional rIT directed to the periplasmic space of Escherichia coli. rITs were recovered by freeze-thawing of pellets from shaking cultures of bacteria grown under osmotic stress (4% NaCl plus 0.5 M sorbitol) in the presence of compatible solutes. Compatible solutes, such as glycine betaine and hydroxyectoine, are low-molecular-weight osmolytes that occur naturally in halophilic bacteria and are known to protect proteins at high salt concentrations. Adding 10 mM glycine betaine for the cultivation of E. coliunder osmotic stress not only allowed the bacteria to grow under these otherwise inhibitory conditions but also produced a periplasmic microenvironment for the generation of high concentrations of correctly folded rITs. Protein purified by combinations of metal ion affinity and size exclusion chromatography was substantially stabilized in the presence of 1 M hydroxyecotine after several rounds of freeze-thawing, even at very low protein concentrations. The binding properties and cytotoxic potency of the rITs were confirmed by competitive experiments. This novel compatible-solute-guided expression and purification strategy might also be applicable for high-yield periplasmic production of recombinant proteins in different expression systems.

scholarly journals Salt Stress-Induced Changes in the Transcriptome, Compatible Solutes, and Membrane Lipids in the Facultatively Phototrophic Bacterium Rhodobacter sphaeroides

2011 ◽  
Vol 77 (21) ◽  
pp. 7551-7559 ◽  
Author(s):  
Minoru Tsuzuki ◽  
Oleg V. Moskvin ◽  
Masayuki Kuribayashi ◽  
Kiichi Sato ◽  
Susana Retamal ◽  
...  
Keyword(s):  
Salt Stress ◽  
Rhodobacter Sphaeroides ◽  
Glycine Betaine ◽  
Mutational Analysis ◽  
Compatible Solutes ◽  
Phospholipid Composition ◽  
Compatible Solute ◽  
Content Type ◽  
Genes Encoding ◽  
Induced Changes

ABSTRACTResponses to NaCl stress were investigated in phototrophically grownAlphaproteobacterium Rhodobacter sphaeroidesby transcriptome profiling, mutational analysis, and measurements of compatible solutes and membrane phospholipids. After exposure to salt stress, genes encoding two putative glycine betaine uptake systems,proVWXandbetS, were highly upregulated. Mutational analysis revealed that BetS, not ProVWX, was the primary transporter of this compatible solute. Upon the addition of salt, exogenous glycine betaine was taken up rapidly, and maximal intracellular levels were reached within minutes. In contrast, synthesis of another important compatible solute inR. sphaeroides, trehalose, increased slowly following salt stress, reaching maximal levels only after several hours. This accumulation pattern was consistent with the more gradual increase in salt-induced transcription of the trehalose biosynthesis operonotsBA. Several genes encoding putative transcription factors were highly induced by salt stress. Multiple copies of one of these factors,crpO(RSP1275), whose product is a member of the cyclic AMP receptor protein/fumarate and nitrate reduction regulator (CRP/FNR) family, improved NaCl tolerance. WhencrpOwas provided in multicopy, expression of genes for synthesis or transport of compatible solutes was unaltered, but the membrane phospholipid composition became biased toward that found in salt-stressed cells. Collectively, this study characterized transcriptional responses to salt stress, correlated changes in transcription with compatible solute accumulation rates, identified the main glycine betaine transporter and trehalose synthase, characterized salt-induced changes in phospholipid composition, and uncovered a transcription factor associated with changes in phospholipids. These findings set the stage for deciphering the salt stress-responsive regulatory network inR. sphaeroides.

scholarly journals Role for Glycine Betaine Transport in Vibrio cholerae Osmoadaptation and Biofilm Formation within Microbial Communities

2005 ◽  
Vol 71 (7) ◽  
pp. 3840-3847 ◽  
Author(s):  
Dagmar Kapfhammer ◽  
Ece Karatan ◽  
Kathryn J. Pflughoeft ◽  
Paula I. Watnick
Keyword(s):  
Microbial Communities ◽  
Vibrio Cholerae ◽  
Glycine Betaine ◽  
Biofilm Formation ◽  
Bacterial Species ◽  
Compatible Solutes ◽  
Compatible Solute ◽  
Human Pathogen ◽  
Biofilm Development ◽  
Solute Transporters

ABSTRACT Vibrio cholerae is a halophilic facultative human pathogen found in marine and estuarine environments. Accumulation of compatible solutes is important for growth of V. cholerae at NaCl concentrations greater than 250 mM. We have identified and characterized two compatible solute transporters, OpuD and PutP, that are involved in uptake of glycine betaine and proline by V. cholerae. V. cholerae does not, however, possess the bet genes, suggesting that it is unable to synthesize glycine betaine. In contrast, many Vibrio species are able to synthesize glycine betaine from choline. It has been shown that many bacteria not only synthesize but also secrete glycine betaine. We hypothesized that sharing of compatible solutes might be a mechanism for cooperativity in microbial communities. In fact, we have demonstrated that, in high-osmolarity medium, V. cholerae growth and biofilm development are enhanced by supplementation with either glycine betaine or spent media from other bacterial species. Thus, we propose that compatible solutes provided by other microorganisms may contribute to survival of V. cholerae in the marine environment through facilitation of osmoadaptation and biofilm development.

scholarly journals Thermoprotection of Bacillus subtilis by Exogenously Provided Glycine Betaine and Structurally Related Compatible Solutes: Involvement of Opu Transporters

2004 ◽  
Vol 186 (6) ◽  
pp. 1683-1693 ◽  
Author(s):  
Gudrun Holtmann ◽  
Erhard Bremer
Keyword(s):  
Bacillus Subtilis ◽  
Glycine Betaine ◽  
Compatible Solutes ◽  
Physiological Role ◽  
Growth Conditions ◽  
Transport Systems ◽  
Moderate Increase ◽  
Low Concentrations ◽  
In Cells

ABSTRACT Bacillus subtilis possesses five osmotically regulated transporters (Opu) for the uptake of various compatible solutes for osmoprotective purposes. We have now found that compatible solutes also function as thermoprotectants for B. subtilis. Low concentrations of glycine betaine enhanced the growth of the B. subtilis wild-type strain JH642 at its maximal growth temperature (52°C) but did not allow an extension of the upper growth limit. A similar enhancement in the growth of B. subtilis was also observed by the addition of several other compatible solutes that are structurally related to glycine betaine or by the addition of proline. Each of these compatible solutes was taken up under heat stress by the cell through the same Opu transporters that are used for their acquisition under osmostress conditions. Northern blot analysis revealed a moderate increase in transcription of the structural genes for each of the Opu transport systems in cells that were propagated at 52°C. In contrast, the uptake level of radiolabeled glycine betaine was very low under high-temperature growth conditions but nevertheless allowed the buildup of an intracellular glycine betaine pool comparable to that found in cells grown at 37°C in the absence of salt stress. Although exogenously added glutamate has only a limited osmoprotective potential for B. subtilis, it was found to be a very effective thermoprotectant. Collectively, our data demonstrate thermoprotection by a variety of compatible solutes in B. subtilis, thus ascribing a new physiological function for this class of compounds in this microorganism and broadening the physiological role of the known osmoprotectant uptake systems (Opu).

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