Organic compatible solutes of halotolerant and halophilic microorganisms

Roberts, Mary F.

doi:10.1186/1746-1448-1-5

Cited by 543 publications

(258 citation statements)

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“…9). This similarity is particularly striking in the region between amino acids 70 and 100, showing a perfect match to the consensus sequence 3 D, characteristic of several alcohol phosphatidyltransferases (24). Based on the overall similarity of chemical reactions catalyzed by the previously characterized proteins from the CDP-alcohol phosphatidyltransferase family, we conjectured that DipB is the most likely candidate for the role of the missing DIPS.…”

Section: Prediction Of Novel Dip Pathway Genes By Comparative Genomicsmentioning

confidence: 96%

“…T he most common mechanism of osmoadaptation in microorganisms involves the accumulation of specific organic osmolytes, so-called compatible solutes, amino acids, sugars, and polyols, that can be taken up from the environment or synthesized de novo (1)(2)(3). In thermophiles and hyperthermophiles, compatible solutes are generally different from those found in mesophiles (4), and many of them additionally contribute to thermoprotection.…”

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confidence: 99%

“…However, two additional enzymes required for DIP biosynthesis have not yet been identified in any organism (3). We used a subsystems-based comparative genomic analysis [as implemented in the SEED platform (22)] to explore the DIP biosynthesis pathway (further termed DIP pathway) in thermophilic species with completely sequenced genomes.…”

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confidence: 99%

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Genomic identification and in vitro reconstitution of a complete biosynthetic pathway for the osmolyte di- myo -inositol-phosphate

Rodionov

Kurnasov

Stec

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

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Di-myo-inositol 1,1 -phosphate (DIP) is a major osmoprotecting metabolite in a number of hyperthermophilic species of archaea and bacteria. Although the DIP biosynthesis pathway was previously proposed, genes encoding only two of the four required enzymes, inositol-1-phosphate synthase and inositol monophosphatase, were identified. In this study we used a comparative genomic analysis to predict two additional genes of this pathway (termed dipA and dipB) that remained missing. In Thermotoga maritima both candidate genes (in an originally misannotated locus TM1418) form an operon with the inositol-1-phosphate synthase encoding gene (TM1419). A predicted inositol-monophosphate cytidylyltransferase activity was directly confirmed for the purified product of T. maritima gene dipA cloned and expressed in Escherichia coli. The entire DIP pathway was reconstituted in E. coli by cloning of the TM1418 -TM1419 operon in pBAD expression vector and confirmed to function in the crude lysate. 31 P NMR and MS analysis revealed that DIP synthesis proceeds via a phosphorylated DIP intermediate, P-DIP, which is generated by the dipBencoded enzyme, now termed P-DIP synthase. This previously unknown intermediate is apparently converted to the final product, DIP, by an inositol monophosphatase-like phosphatase. These findings allowed us to revise the previously proposed DIP pathway. The genomic survey confirmed its presence in the species known to use DIP for osmoprotection. Among several newly identified species with a postulated DIP pathway, Aeropyrum pernix was directly proven to produce this osmolyte.comparative genomics ͉ di-myo-inositol-1,3-phosphate biosynthesis ͉ Thermotoga maritima T he most common mechanism of osmoadaptation in microorganisms involves the accumulation of specific organic osmolytes, so-called compatible solutes, amino acids, sugars, and polyols, that can be taken up from the environment or synthesized de novo (1-3). In thermophiles and hyperthermophiles, compatible solutes are generally different from those found in mesophiles (4), and many of them additionally contribute to thermoprotection.Di-myo-inositol 1,1Ј-phosphate (DIP) is one of the major compatible solutes in a number of thermophilic archaea of the genera Pyrococcus, Methanococcus, Thermococcus, and Archaeoglobus and bacteria belonging to the genera Aquifex, Rubrobacter, and Thermotoga, including Thermotoga maritima and Thermotoga neapolitana (4-7). DIP levels are highly increased at supraoptimal growth temperatures in both Methanococcus igneus and Thermotogales, suggesting that this solute also plays a thermoprotective role (6,8).Based on the study in M. igneus (9) and the reported stereochemistry of DIP (10), the pathway of DIP biosynthesis was originally proposed to occur in four steps: (i) synthesis of L-myoinositol-1-phosphate (L-I-1-P) from glucose-6-phosphate by NAD ϩ -dependent L-I-1-P synthase [inositol-1-phosphate synthase (IPS)]; (ii) hydrolysis of some of the L-I-1-P by inositol monophosphatase (IMP); (iii) coupling of the L-I-1-P with ...

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Section: Prediction Of Novel Dip Pathway Genes By Comparative Genomicsmentioning

confidence: 96%

mentioning

confidence: 99%

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Genomic identification and in vitro reconstitution of a complete biosynthetic pathway for the osmolyte di- myo -inositol-phosphate

Rodionov

Kurnasov

Stec

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

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“…The second phase is the more long-term strategy, the synthesis and/or accumulation of compatible solutes that can be amassed in high concentrations without disturbing vital cellular functions (27). Compatible solutes include but are not limited to trehalose, glycerol, mannitol, free amino acids such as glutamate, glutamine, and proline and their derivatives betaine, glycine betaine, and ectoine (27)(28)(29)(30)(31)(32)(33). It has been proposed that most bacteria use the trimethylammonium compound glycine betaine (N,N,N-trimethylglycine) as their preferred compatible solute (30,34).…”

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confidence: 99%

Biosynthesis of the Osmoprotectant Ectoine, but Not Glycine Betaine, Is Critical for Survival of Osmotically Stressed Vibrio parahaemolyticus Cells

Ongagna-Yhombi

Boyd

2013

Appl Environ Microbiol

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Vibrio parahaemolyticus is a halophile present in marine and estuarine environments, ecosystems characterized by fluctuations in salinity and temperature. One strategy to thrive in such environments is the synthesis and/or uptake of compatible solutes. The V. parahaemolyticus genome contains biosynthesis systems for both ectoine and glycine betaine, which are known to act as compatible solutes in other species. We showed that V. parahaemolyticus had a 6% NaCl tolerance when grown in M9 minimal medium with 0.4% glucose (M9G) with a >5-h lag phase. By using 1 H nuclear magnetic resonance spectroscopy ( 1 H-NMR) analysis, we determined that cells synthesized ectoine and glutamate in a NaCl-dependent manner. The most effective compatible solutes as measured by a reduction in lag-phase growth in M9G with 6% NaCl (M9G 6% NaCl) were in the order glycine betaine > choline > proline ‫؍‬ glutamate > ectoine. However, V. parahaemolyticus could use glutamate or proline as the sole carbon source, but not ectoine or glycine betaine, which suggests that these are bona fide compatible solutes. Expression analysis showed that the ectA and betA genes were more highly expressed in log-phase cells, and expression of both genes was induced by NaCl up-shock. Under all conditions examined, the ectA gene was more highly expressed than the betA gene. Analysis of inframe deletions in betA and ectB and in a double mutant showed that the ectB mutant was defective for growth, and this defect was rescued by the addition of glycine betaine, proline, ectoine, and glutamate, indicating that these compounds are compatible solutes for this species. The presence of both synthesis systems was the predominant distribution pattern among members of the Vibrionaceae family, suggesting this is the ancestral state.

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“…Osmolytes (also known as compatible solutes) do not interfere with cellular metabolism. They are represented by compounds of different classes: (i) zwitterions (amino acids and their derivatives including ectoines and betaines), (ii) neutral solutes (sugars and polyols) and (iii) anionic solutes where the negative charge is supplied by a carboxylate, phosphate or sulfate (Galinski, 1995;Roberts, 2004;2005). Many bacteria, including non-halophilic, accumulate compatible solutes at hyperosmotic conditions either through de novo synthesis or by uptake from surrounding environment.…”

Section: Introductionmentioning

confidence: 99%

Genetic and Biochemical Aspects of Ectoine Biosynthesis in Moderately Halophilic and Halotolerant Methylotrophic Bacteria

Khmelenina

Mustakhimov

Reshetnikov

et al. 2010

American Journal of Agricultural and Biological Sciences

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Problem statement:The cyclic imino acid ectoine is a widely distributed compatible solute synthesizing by halophilic and halotolerant bacteria to prevent osmotic stress at high external salinity. This water-keeping compound is used in a variety of commercial cosmetics and therapeutic products. Approach: Development of integrated, predictive functional model of the metabolic and regulatory netwoks of ectoine-producing microbes is an active area of research. In this article we present a brief overview of the current knowledge on genetic and biochemical aspects of ectoine biosynthesis in aerobic halophilic and halotolerant bacteria utilizing C 1 compounds (methylotrophs). Although enzymology and genetics of the ectoine biosynthesis in methylotrophs are similar to other halophilic bacteria, the regulatory patterns are different. In all methylotrophic bacteria studied, the genes coding for specific enzymes of ectoine biosynthesis: Diaminobutyric Acid (DABA) aminotransferase (EctB), DABA acetyltransferase (EctA) and ectoine synthase (EctC) are organized into ectABC or ectABC-ask, whith is linked to gene encoding Aspartokinase isozyme (Ask). Results: Remarkably, the methylotrophic bacteria possessing a four-gene cluster showed higher halotolerance and accumulated more ectoine than bacteria with a cluster composed of three genes. The DABA acetyltransferases from three methylotrophic species have been comparatively characterized. The properties of the enzymes correlate with eco-physiological and metabolic particularities of the host. Some elements of the regulatory system governing the ectoine pathway operation have been revealed in both methane and methanol utilizing bacteria. In Methylomicrobium alcaliphilum transcription of the ectABC-ask operon is initiated from two σ 70 -like promoters and controlled by the EctR, a MarR-type negative regulator. EctR orthologs were identified in genomes of several heterotrophic halophilic bacteria. Here we present genomic data indicating that similar regulatory system may occur in diverse halophilic and halotolerant bacteria. Conclusion: Currently available data suggest that in methylotrophic bacteria the ectoine biosynthesis pathways are evolutionary well conserved, particularly with respect to the genes and enzymes involved. However, some differences in the ect-gene cluster organization and regulation could be observed.

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Organic compatible solutes of halotolerant and halophilic microorganisms

Cited by 543 publications

References 175 publications

Genomic identification and in vitro reconstitution of a complete biosynthetic pathway for the osmolyte di- myo -inositol-phosphate

Genomic identification and in vitro reconstitution of a complete biosynthetic pathway for the osmolyte di- myo -inositol-phosphate

Biosynthesis of the Osmoprotectant Ectoine, but Not Glycine Betaine, Is Critical for Survival of Osmotically Stressed Vibrio parahaemolyticus Cells

Genetic and Biochemical Aspects of Ectoine Biosynthesis in Moderately Halophilic and Halotolerant Methylotrophic Bacteria

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