A Synthetic Medium for Extremely Halophilic Bacteria

Ōnishi, Hiroshi; McCance, Margaret E.; Gibbons, N. E.

doi:10.1139/m65-044

Cited by 95 publications

(37 citation statements)

References 8 publications

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“…This article must therefore be hereby marked "advertisement" in accordance with 18 U. S. C. §1734 solely to indicate this fact. modification (12) of the medium of Sehgal and Gibbons (13 (14).…”

Section: Methodsmentioning

confidence: 99%

Bacteriorhodopsin is an inside-out protein.

Engelman¹,

Zaccaı̈²

1980

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

203

102

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Neutron scattering is particularly useful when parts of a structure can be deuterated. From Halobacterium halobium we have obtained, by biosynthetic incorporation, purple membranes in which all of the valines or all of the phenylalanines are present in deuterated form. Difference Fourier techniques permit a general assessment of the distribution of valine and phenylalanine in projections of the purple membrane structure. These show that valine is distributed toward the periphery of a single bacteriorhodopsin molecule, whereas phenylalanine is distributed toward its center. We use the facts that the amino acid sequence is known and that much of it can be assigned to the a helices of the bacteriorhodopsin structure to interpret our results. Comparison of our maps with the distribution of valine and phenylalanine around a-helical rimeters establishes the distribution of other amino acids and reads to the conclusion that the charged and polar groups of the bacteriorhodopsin molecule tend to lie at the molecular interior, away from contact with lipid, while the nonpolar surfaces are directed outward, making contact with the lipid regions. Thus, the protein is "inside-out" compared with the organization of soluble proteins. Halobacterium halobium is an organism that lives in environments containing high concentrations of salt (1). When oxygen supplies become limited, the organism synthesizes a specialized region of the plasma membrane that converts energy from visible light into stored energy by pumping protons across the plasma membrane (2, 3). This specialized region, the purple membrane, was discovered as a stable structure in isolation procedures at low ionic strength (4, 5 Two of the major advances in understanding this structure have come from electron microscopy and amino acid sequence analysis. By combining real space imaging and diffraction measurements in the electron microscope, Henderson and Unwin (7) combined information from a series of tilted specimens to obtain a three-dimensional density map at 7-A resolution. The bacteriorhodopsin molecule was seen to contain seven rods of density extending through the membrane; these have been interpreted as a helices on the basis of their dimensions and packing.To progress in understanding to the level of functional analysis and chemical detail, an essential step is knowledge of the amino acid sequence of bacteriorhodopsin. Recent reports describe the successful conclusion of years of effort to determine it (8, 9). The agreement of these reports with other, independent studies (10) provides confidence that the sequence is substantially correct. Together with the sequence information, useful data concerning the location of proteolytic cleavage points on the bacteriorhodopsin molecule were reported in these studies. Because the rods of density observed in the three-dimensional electron microscopic study lend themselves to interpretation as segments of a helix, it became of interest to attempt to fit the bacteriorhodopsin sequence information into a series of...

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Section: Methodsmentioning

confidence: 99%

Bacteriorhodopsin is an inside-out protein.

Engelman¹,

Zaccaı̈²

1980

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

203

102

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“…Organisms belonging to the genera Halobacterium, Haloarcula, Haloferax and Halococcus were grown in the synthetic Onishi-McCance-Gibbons medium (OMG medium), pH 6.2 (11). Natronobacterium pharaonis was grown in OMG medium adjusted pH at 9.0.…”

mentioning

confidence: 99%

Ubiquitous occurrence of agmatine as the major polyamine within extremely halophilic archaebacteria.

Hamana

Itoh

1995

J. Gen. Appl. Microbiol.

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Previous studies have indicated that bacterial polyamine patterns may be useful for chemotaxonomic evaluations (6). In the course of investigations on the possible existence of unusual polyamines in extremely halophilic archaebacteria, we detected agmatine as the major polyamine and arginine decarboxylase (ADC) activity which produces agmatine from arginine in the cells of some strains of Halobacterium and Halococcus (5,8). These extreme halophiles were devoid of any other polyamines and of lysine decarboxylase (LDC) and ornithine decarboxylase (ODC) activities which produce cadaverine and putrescine, respectively (5, 8). Extremely halophilic, nonmethanogenic archaebacteria are comprised of essentially two groups: extreme halophiles that grow at neutrality include the genera Halobacterium, Haloarcula, Haloferax and Halococcus and extremely haloalkaliphilic isolates that grow only at high pH include the genera Natronobacterium and Natronococcus (3,10,13). In the present study, polyamines of 41 strains of the published species of extremely halophilic, nonmethanogenic archaebacteria listed in Table 1 were analyzed to evaluate polyamine type as a chemotaxonomic marker.Organisms belonging to the genera Halobacterium, Haloarcula, Haloferax and Halococcus were grown in the synthetic Onishi-McCance-Gibbons medium (OMG medium), pH 6.2 (11). Natronobacterium pharaonis was grown in OMG medium adjusted pH at 9.0. The medium contains 15 amino acids including arginine and lysine, AMP, UMP, trisodium citrate, glycerol, various inorganic salts, 2% MgSO4 7H20 and 25% NaCI but not ornithine and polyamines. Three other species of Natronobacterium and Natronococcus occultus which did not grow in

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“…An amino acid mixture is necessary (18), and other organic compounds such as glycerol can stimulate growth (18). Much research has been done on amino acid transport in halobacteria (19), and it was concluded that all amino acids except cysteine were transported through the membrane.…”

mentioning

confidence: 99%

Mevalonic acid is partially synthesized from amino acids in Halobacterium cutirubrum: a 13C nuclear magnetic resonance study

Ekiel¹,

Sprott²,

Smith³

1986

J Bacteriol

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13C nuclear magnetic resonance revealed an unusual pathway for the biosynthesis of lipids in Halobacterium cutirubrum and H. halobium. Mevalonic acid was not synthesized from three acetyl-coenzyme A molecules, as has been suggested previously, and the branch-methyl and methine carbons in phytanyl chains were derived from neither acetate nor glycerol. Instead, they were supplied by the degradation of amino acids, in particular of lysine. Presumably, two different types of two-carbon fragments were used simultaneously by halobacteria for the biosynthesis of mevalonate. The labeling pattern of squalene supported the above conclusions. Based on these data, a general scheme is proposed to account for the contribution of lysine-to-lipid biosynthesis.Our previous papers on the application of the 13C-nuclear magnetic resonance (NMR) technique to study the metabolic pathways of methanogenic bacteria (7,8,10) showed several significant differences in biosynthesis when compared with the biosynthesis of other amino acids by bacteria and eucaryotes. Similar studies for comparison with halobacteria are lacking. Halobacteria are archaebacteria also, but with an aerobic rather than anaerobic mode of metabolism.Halobacteria require quite complicated media for growth, and, in contrast to the aceticlastic methanogens, acetate can be used for growth only when combined with several additional carbon sources.

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A Synthetic Medium for Extremely Halophilic Bacteria

Cited by 95 publications

References 8 publications

Bacteriorhodopsin is an inside-out protein.

Bacteriorhodopsin is an inside-out protein.

Ubiquitous occurrence of agmatine as the major polyamine within extremely halophilic archaebacteria.

Mevalonic acid is partially synthesized from amino acids in Halobacterium cutirubrum: a 13C nuclear magnetic resonance study

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