Mechanisms of Halotolerance in Microorganisms

Vreeland, Russell H.

doi:10.3109/10408418709104443

Cited by 113 publications

(85 citation statements)

References 81 publications

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“…As high amounts of these solutes are required for further research into possible applications, these data are of importance for the possible selection of producer strains. Although halophilic heterotrophic aerobic eubacteria have been the objects of research for several decades (Rodriguez-Valera, 1988 ;Vreeland, 1987 ;Kushner, 1988;Kushner & Kamekura, 1988), their mechanism of osmoadaptation has remained obscure. Neither inorganic ions nor organic molecules were detected in sufficiently high intracellular concentrations to balance the low external water activity.…”

Section: Separation and Quantijication Of Organic Osmolytes By Hplcmentioning

confidence: 99%

The predominant role of recently discovered tetrahydropyrimidines for the osmoadaptation of halophilic eubacteria

Severin

Wohlfarth

Galinski

1992

Journal of General Microbiology

176

144

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The aim of this investigation was to perform an extensive screening using HPLC and I3C-NMR spectroscopy to disclose the spectrum of osmolytes produced by aerobic heterotrophic and anoxygenic phototrophic eubacteria. The most predominant solutes detected within a wide range of marine and halophilic micro-organisms were two recently discovered tetrahydropyrimidines ectoine and hydroxyectoine, which were synthesized in response to osmotic stress.

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Section: Separation and Quantijication Of Organic Osmolytes By Hplcmentioning

confidence: 99%

The predominant role of recently discovered tetrahydropyrimidines for the osmoadaptation of halophilic eubacteria

Severin

Wohlfarth

Galinski

1992

Journal of General Microbiology

176

144

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“…The consequences are changing cellular volume and turgor pressure that exert strong mechanical forces on the cytoplasmic membrane and associated proteins and, if too high, preclude growth of the bacterium and eventually cause cell death 1 . To cope with osmotic stress, bacteria evolved several strategies such as adapting their intracellular osmolality [2][3][4] or increasing their cell wall stability 5 , allowing them to grow in a broad range of solute concentrations.…”

Section: Introductionmentioning

confidence: 99%

Ubiquinone accumulation improves osmotic-stress tolerance in Escherichia coli

2014

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Bacteria are thought to cope with fluctuating environmental solute concentrations primarily by adjusting the osmolality of their cytoplasm. To obtain insights into underlying metabolic adaptions, we analyzed the global metabolic response of Escherichia coli to sustained hyperosmotic stress using non-targeted mass spectrometry. We observed that 52% of 1,071 detected metabolites, including known osmoprotectants, changed abundance with increasing salt challenge. Unexpectedly, unsupervised data analysis revealed a substantial increase of most intermediates in the ubiquinone-8 (Q8) biosynthesis pathway and a 110-fold accumulation of Q8 itself, as confirmed by quantitative lipidomics. We then demonstrate that Q8 is necessary for acute and sustained osmotic stress tolerance using Q8 mutants and tolerance rescue through feeding non-respiratory Q8 analogues. Finally, in vitro experiments with artificial liposomes reveal mechanical membrane stabilization as a principal mechanism of Q8-mediated osmoprotection. Thus, we find that besides regulating intracellular osmolality, E. coli enhances its cytoplasmic membrane stability to withstand osmotic stress. AbstractBacteria are thought to cope with fluctuating environmental solute concentrations primarily by adjusting the osmolality of their cytoplasm. To obtain insights into underlying metabolic adaptions, we analyzed the global metabolic response of Escherichia coli to sustained hyperosmotic stress using non-targeted mass spectrometry. We observed that 52% of 1,071 detected metabolites, including known osmoprotectants, changed abundance with increasing salt challenge. Unexpectedly, unsupervised data analysis revealed a substantial increase of most intermediates in the ubiquinone-8 (Q8) biosynthesis pathway and a 110-fold accumulation of Q8 itself, as confirmed by quantitative lipidomics. We then demonstrate that Q8 is necessary for acute and sustained osmotic stress tolerance using Q8 mutants and tolerance rescue through feeding non-respiratory Q8 analogues.Finally, in vitro experiments with artificial liposomes reveal mechanical membrane stabilization as a principal mechanism of Q8-mediated osmoprotection. Thus, we find that besides regulating intracellular osmolality, E. coli enhances its cytoplasmic membrane stability to withstand osmotic stress.

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“…antiporter to maintain a large Na ? gradient in the cytoplasm (Vreeland 1987). Within the CC, three of the strains, Pseudomonas fluorescens (Viggor et al 2013), Brevundimonas and Stenotrophomonas (Mahjoubi et al 2013) may possess such mechanism since they were reported in other studies to survive in the sea and marine environments.…”

Section: Resultsmentioning

confidence: 99%

“…Vreeland (1987) reported strains could adapt to high salinity by concentrating compatible solutes to create an osmotic balance between the cytoplasm and the external environment or by altering membrane permeability to control the movement of water and allowing the cell to exist with an ionically dilute cytoplasm. Some bacterial strains can lower its cytoplasmic ionic content compared with the outside medium by activating a Na ?…”

Section: Resultsmentioning

confidence: 99%

Self-immobilised bacterial consortium culture as ready-to-use seed for crude oil bioremediation under various saline conditions and seawater

Kee

Hazaimeh

Mutalib

et al. 2014

Int. J. Environ. Sci. Technol.

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Biodegradation of crude oil hydrocarbon by microorganisms in seawater is generally slow because of the harsh environmental condition due to high salinity. The aim of this study was to compare sawdust (SD) and oil palm empty fruit bunch wastes as suitable carrier material to immobilise hydrocarbon-degrading bacterial consortium culture to accelerate and improve crude oil degradation in seawater. The consortium culture was found able to tolerate salinity up to 3 %, where the degradation of crude oil was not inhibited (p [ 0.05). In artificial seawater, suspension of bacterial consortium culture was able to degrade 83.3 ± 3.00 % of crude oil within 8 weeks, which indicated the possibility of using consortium culture in seawater. When tested in seawater, suspension of consortium culture managed to degrade 47.7 ± 1.53 % of crude oil in 8 weeks. In order to improve the performance of consortium culture, immobilisation of consortium culture onto SD and oil palm empty fruit bunch was successfully undertaken when formation of biofilm layers was observed under scanning electron microscope. Immobilising consortium culture onto oil palm empty fruit bunch and SD was shown to increase crude oil biodegradation to 68.7 ± 4.04 and 62.3 ± 5.51 % in 8 weeks, respectively. This study demonstrated immobilisation of consortium culture onto SD and oil palm empty fruit bunch can be utilised as ready-touse seeds to improve and accelerate crude oil biodegradation in seawater.

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Mechanisms of Halotolerance in Microorganisms

Cited by 113 publications

References 81 publications

The predominant role of recently discovered tetrahydropyrimidines for the osmoadaptation of halophilic eubacteria

The predominant role of recently discovered tetrahydropyrimidines for the osmoadaptation of halophilic eubacteria

Ubiquinone accumulation improves osmotic-stress tolerance in Escherichia coli

Self-immobilised bacterial consortium culture as ready-to-use seed for crude oil bioremediation under various saline conditions and seawater

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