Abstract

10.1101/gr.190201 The genome of the halophilic archaeon Halobacterium sp. NRC-1 and predicted proteome have been analyzed by computational methods and reveal characteristics relevant to life in an extreme environment distinguished by hypersalinity and high solar radiation: (1) The proteome is highly acidic, with a median pI of 4.9 and mostly lacking basic proteins. This characteristic correlates with high surface negative charge, determined through homology modeling, as the major adaptive mechanism of halophilic proteins to function in nearly saturating salinity. (2) Codon ...

Abstract

To better understand the extremely halophilic archaeon Halobacterium species NRC-1, we analyzed its soluble proteome by two-dimensional liquid chromatography coupled to electrospray ionization tandem mass spectrometry. A total of 888 unique proteins were identified with a ProteinProphet probability (P) between 0.9 and 1.0. To evaluate the biochemical activities of the organism, the proteomic data were subjected to a biological network analysis using our BMSorter software. This allowed us to examine the proteins expressed in different biomodules and study the interactions between ...

Abstract

SummaryThe genome of Halobacterium salinarum encodes four proteins of the structural maintenance of chromosomes (SMC) protein superfamily. Two proteins form a novel subfamily and are named 'SMC-like proteins of H. salinarum' (Sph1 and Sph2). Northern blot analyses revealed that sph1 and hp24, the adjacent gene, are solely transcribed in exponentially growing, but not in stationary phase, cells. A synchronization procedure was developed, which makes use of the DNA polymerase inhibitor aphidicolin and leads to highly synchronous cultures. It allowed us for ...

Abstract

The effect of anaerobiosis on the gas vesicle formation was investigated in three Halobacterium salinarum strains, Haloferax mediterranei and in Haloferax volcanii transformants. All these strains significantly reduced gas vesicle formation or lacked these structures under anoxic conditions. When grown by arginine fermentation, Hbt. salinarum PHH4 lacked gas vesicles, whereas Hbt. salinarum PHH1 and NRC-1 contained 5201320 small gas vesicles arranged in two to three aggregates per cell instead of the 30201380 gas vesicles present under oxic conditions. The enlargement presumably stopped due ...

Abstract

ABSTRACTHalocins H6 and H4 are bacteriocin-like substances capable of killing sensitive halobacterial cells by affecting the bioenergetic steady state across the membrane. The effect of either halocin on living cells is similar, but the primary target of each is different. Halocin H6 inhibited light-induced Na[IMG]_8668_tex2html_wrap1344.gif"> out-flow in membrane vesicles of Halobacterium halobium. H4 did not, but instead slowed the H[IMG]_8668_tex2html_wrap1344.gif"> return-flow in the dark after illumination. Halocin H6 adsorbs firmly to both whole cells and membrane vesicles. The conclusion is that ...

Abstract

Pleomorphic Halobacterium strains isolated from the Dead Sea (H. volcanii, H. marismortui) require high concentrations of divalent cations (75 mM Mg2+) for growth. When suspended in medium containing less than 50 mM Mg2+ cells lose their native shape within minutes and become spherical. This occurs even at elevated sodium chloride concentrations. Concomitant with the morphological changes, a high mlecular weight component which is positive in Coomassie Brilliant Blue and in periodate Schiff stain is released into the surrounding medium. At divalent ...

Abstract

All tested strains of halophilic archaebacteria of the genera Halobacterium, Haloarcula, Haloferax, and Natronobacterium lysed in 1% Bacto-Peptone (Difco) containing 25% NaCl, whereas no lysis was observed with other strains belonging to archaebacteria of the genera Halococcus, Natronococcus, and Sulfolobus, methanogenic bacteria, and moderately halophilic eubacteria. Substances in Bacto-Peptone which caused lysis of halobacteria were purified and identified as taurocholic acid and glycocholic acid. High-performance liquid chromatography analyses of peptones revealed that Bacto-Peptone contained nine different bile acids, with a total ...

Abstract

When Halobacterium halobium R1 was cultured with cell recycle in a bioreactor equipped with an external hollow fiber membrane unit, the cell and bacteriorhodopsin concentrations reached in 10 days were 30.3 g cell dry weight/l and 282 mg/l, respectively. The productivity of bacteriorhodopsin (1.15 mg/l·h) was much higher than that (0.16 mg/l·h) obtained by typical batch fermentation. © Rapid Science Ltd. 1998 ...

Abstract

Halobacterium sp. NRC-1 insoluble membrane and soluble cytoplasmic proteins were isolated by ultracentrifugation of whole cell lysate. Using an ion trap mass spectrometer equipped with a C18 trap electrospray ionization emitter/micro-liquid chromatography column, a number of trypsin-generated peptide tags from 426 unique proteins were identified. This represents approximately one-fifth of the theoretical proteome of Halobacterium. Of these, 232 proteins were found only in the soluble fraction, 165 were only in the insoluble membrane fraction, and 29 were in both fractions. There ...

Abstract

The fine structure of gas vacuoles was examined in two blue-green algae, two green bacteria, three purple sulfur bacteria, and two halobacteria. The gas vacuole is a compound organelle, composed of a variable number of gas vesicles. These are closed, cylindrical, gas-containing structures with conical ends, about 80 to 100 nm in width and of variable length, ranging from 0.2 to over 1.0 microm. The wall of the gas vesicle is a non-unit membrane 2 to 3 nm in thickness, bearing ...

Abstract

BACKGROUND:The model halophile Halobacterium sp. NRC-1 was among the first Archaea to be completely sequenced and many post-genomic tools, including whole genome DNA microarrays are now being applied to its analysis. This extremophile displays tolerance to multiple stresses, including high salinity, extreme (non-mesophilic) temperatures, lack of oxygen, and ultraviolet and ionizing radiation.RESULTS:In order to study the response of Halobacterium sp. NRC-1 to two common stressors, salinity and temperature, we used whole genome DNA microarrays to assay for changes in gene expression ...

Abstract

Halobacterium-halobium NRC-1 harbors a 200-kb plasmid, pNRC100, which contains a cluster of genes for synthesis of buoyant gas-filled vesicles. Physical mapping of pNRC100 by using pulsed-field gel electrophoresis showed the presence of a large (35 to 38-kb) inverted repeat (IR) sequence. Inversion isomers of pNRC100 were demonstrated by Southern hybridization analysis using two restriction enzymes, AflII and SfiI, that cut asymmetrically within the intervening small single-copy region and the large single-copy region, respectively, but not within the large IRs. No inversion ...

Abstract

The genome of Halobacterium sp. strain NRC-1 contains a large gene cluster, gvpMLKJIHGFEDACNO, that is both necessary and sufficient for the production of buoyant gas-filled vesicles. Due to the resistance of gas vesicles to solubilization, only the major gas vesicle protein GvpA and a single minor protein, GvpC, were previously detected. Here, we used immunoblotting analysis to probe for the presence of gas vesicle proteins corresponding to five additional gvp gene products. Polyclonal antisera were raised in rabbits against LacZ-GvpF, -GvpJ, ...

Abstract

The gas vesicle is a hollow structure made of protein. It usually has the form of a cylindrical tube closed by conical end caps. Gas vesicles occur in five phyla of the Bacteria and two groups of the Archaea, but they are mostly restricted to planktonic microorganisms, in which they provide buoyancy. By regulating their relative gas vesicle content aquatic microbes are able to perform vertical migrations. In slowly growing organisms such movements are made more efficiently than by swimming with ...

Abstract

Responses of Halobacterium halobium cells to chemical stimuli have been shown by a capillary technique. Cells were attacted by D-glucose and several amino acids and repelled by phenol. Certain chemicals, such as acetate, benzoate, indole, and NiSO4, that are known to act as repellents of Escherichia coli cells served as attractants for Halobacterium. In the presence of ethionine, sensitivity to attractants was reduced. Arsenate prevented the attraction by glucose without lowering the cellular adenosine 5'-triphosphate level. The ability for chemo-accumulation toward ...

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PMC216711

Abstract

Flagellated envelopes of Halobacterium salinarium cells were prepared by lysis with taurodeoxycholate. After solubilization of the envelopes with Triton X-100 at high ionic strength, flagella and round patches from which numerous flagella emerged were isolated by gel filtration chromatography. We conclude that the flagellar bundle of H. salinarium is inserted into a differentiated polar cap structure. ...

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PMC196367

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PMC1366590

Abstract

A three-dimensional tracking microscope was used to quantify the effects of temperature (50 to 80°C) and pH (2 to 4) on the motility of ...

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PMC93892

Abstract

Gas vesicles, isolated from lysed ...

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PMC285365

Abstract

Abstract Halophilic archaebacteria (haloarchaea) thrive in environments with salt concentrations approaching saturation, such as natural brines, the Dead Sea, alkaline salt lakes and marine solar salterns; they have also been isolated from rock salt of great geological age (195–250 million years). An overview of their taxonomy, including novel isolates from rock salt, is presented here; in addition, some of their unique characteristics and physiological adaptations to environments of low water activity are reviewed. The issue of extreme long-term microbial survival is ...

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PMC17314

Abstract

BACKGROUND:Previous studies indicated that recombinant gas vesicles (r-GV) from a mutant strain of Halobacterium sp. NRC-1 could express a cassette containing test sequences of SIVmac gag derived DNA, and function as an antigen display/delivery system. Tests using mice indicated that the humoral immune response to the gag encoded sequences evoked immunologic memory in the absence of an exogenous adjuvant.RESULTS:The goal of this research was to extend this demonstration to diverse gene sequences by testing recombinant gas vesicles displaying peptides encoded by ...

Abstract

Gas vesicles, isolated from lysed Halobacterium halobium cells, gave an amino acid analysis which accounted for 78% of the weight, and the balance was mainly salt and water. One percent of tightly bound d-galactose was found, as well as 2% of phosphate that was not released by treatment which promotes beta-elimination, by hydrolytic release of the galactose, by carboxymethylation of lysine, or by alkaline phosphatase digestion. Only a trace of lipid was detected, and it appeared to have a polyisoprenoid structure. ...