Red, Extremely Halophilic, but not Archaeal: The Physiology and Ecology of Salinibacter ruber, a Bacterium Isolated from Saltern Crystallizer Ponds

Oren, Aharon; Rodrı́guez-Valera, Francisco; Antón, Josefa; Benlloch, Susana; Rosselló‐Móra, Ramon; Amann, Rudolf; Coleman, J. R.; Russell, Nicholas J.

doi:10.1007/978-3-662-07656-9_4

Cited by 25 publications

(14 citation statements)

References 21 publications

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“…Genomic analysis suggests that this resemblance has arisen through convergence at the physiological level (different genes producing similar overall phenotype) and the molecular level (independent mutations yielding similar sequences or structures). Some genes and gene clusters may have been derived from the Halobacteriaceae by lateral transfer (Oren, ; Oren et al ., ; Mongodin et al ., ). The impact of these modular adaptive elements on the cell biology and ecology of S. ruber is substantial, affecting salt adaptation, bioenergetics, and photobiology.…”

Section: Discussionmentioning

confidence: 98%

Salinibacter: an extremely halophilic bacterium with archaeal properties

Oren

2013

FEMS Microbiol Lett

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The existence of large number of a member of the Bacteroidetes in NaCl-saturated brines in saltern crystallizer ponds was first documented in 1999 based on fluorescence in situ hybridization studies. Isolation of the organism and its description as Salinibacter ruber followed soon. It is a rod-shaped, red-orange pigmented, extreme halophile that grows optimally at 20-30% salt. The genus is distributed worldwide in hypersaline environments. Today, the genus Salinibacter includes three species, and a somewhat less halophilic relative, Salisaeta longa, has also been documented. Although belonging to the Bacteria, Salinibacter shares many features with the Archaea of the family Halobacteriaceae that live in the same habitat. Both groups use KCl for osmotic adjustment of their cytoplasm, both mainly possess salt-requiring enzymes with a large excess of acidic amino acids, and both contain different retinal pigments: light-driven proton pumps, chloride pumps, and light sensors. Salinibacter produces an unusual carotenoid, salinixanthin that forms a light antenna and transfers energy to the retinal group of xanthorhodopsin, a light-driven proton pump. Other unusual features of Salinibacter and Salisaeta include the presence of novel sulfonolipids (halocapnine derivatives). Salinibacter has become an excellent model for metagenomic, biogeographic, ecological, and evolutionary studies.

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Section: Discussionmentioning

confidence: 98%

Salinibacter: an extremely halophilic bacterium with archaeal properties

Oren

2013

FEMS Microbiol Lett

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“…Many of the enzymes of S. ruber are truly halophilic, requiring salt for activity and/or stability. Examples are the NAD-dependent isocitrate dehydrogenase [5], the fatty acid synthetase complex [6], and the NADP-linked glucose-6-phosphate dehydrogenase [7]. Other enzymes such as the NADP-dependent isocitrate dehydrogenase [5] and glycerol kinase (Sher, Mana and Oren, submitted) may function as well in the presence of high salt and in its absence.…”

Section: Introductionmentioning

confidence: 99%

Occurrence of two different glutamate dehydrogenase activities in the halophilic bacteriumSalinibacter ruber

Bonete¹,

Pérez-Pomares²,

Díaz³

et al. 2003

FEMS Microbiology Letters

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Salinibacter ruber, an extremely halophilic member of the domain Bacteria, has two different cytoplasmic glutamate dehydrogenase activities, marked as GDHI and GDHII. GDHI showed a strong dependence on high salt concentrations for stability, but not for activity, displaying maximal activity in the absence of salts. GDHII depended on high salt concentrations for both activity and stability. It catalyzed amination of 2-oxoglutarate with optimal activity in 3 M KCl at pH 8. No activating effect was found when NaCl was replaced by KCl. Only GDHII displayed activity in the deamination reaction of glutamate with an optimal pH of 9.5. Both enzymes were activated by certain amino acids (L-leucine, L-histidine, L-phenylalanine) and by nucleotides such as ADP or ATP. A low-molecular-mass cytoplasmic fraction was found to be a highly effective activator of GDHII in the presence of high NaCl concentrations.

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“…Phylogenetically, Salinibacter belongs to the order Cytophagales (3), but when its physiology is examined, with particular reference to the mode of haloadaptation, there is a surprising similarity between this extremely halophilic bacterium and the Archaea of the family Halobacteriaceae (23).…”

Section: Discussionmentioning

confidence: 99%

“…The membrane lipids of S. ruber are typical for the bacterial domain, with glycerophospholipids containing ester-linked fatty acyl chains and not ether-linked phytanyl chains. In particular, phosphatidylcholine (PC), N,Ndimethylphosphatidyletanolamine (NN-PE), phosphatidylserine (PS), phosphatidylglycerol (PG), and bisphosphatidylglycerol (BPG) are the major membrane phospholipids in Salinibacter (23).…”

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confidence: 99%