Browse
Submit Data
Databases
API
Help

Dataset Information

34 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Potassium stress growth characteristics and energetics in the haloarchaeon Haloarcula marismortui.

ABSTRACT: Growth characteristics surrounding halophilic archaeal organisms are extremely limited in the scientific literature, with studies tending toward observing changes in cellular generation times under growth conditions limited to changes in temperature and sodium chloride concentrations. Currently, knowledge of the ionic stress experienced by haloarchaeal species through an excess or depletion of other required ions is lacking at best. The halophilic archaeon, Haloarcula marismortui, was analyzed under extreme ionic stress conditions with a specific focus on induced potassium ion stress using growth curves and analysis of the intracellular ion concentrations. Generation times were determined under potassium chloride concentrations ranging from 8 to 720 mM, and also in the presence of the alternative monovalent cations of lithium, rubidium, and cesium under limiting potassium conditions. Intracellular ion concentrations, as determined by inductively coupled mass spectrometry (ICP-MS), indicate a minimum intracellular total ion requirement of 1.13 M while tolerating up to 2.43 M intracellular concentrations. The presence of intracellular rubidium and cesium indicates that monovalent ion transport is important for energy production. Comparison of eight archaeal genomes indicates an increased diversity of potassium transport complex subunits in the halophilic organisms. Analysis of the generation times, intracellular concentrations and genome survey shows Har. marismortui exhibits an ability to cope with monovalent cation concentration changes in its native environment and provides insight into the organisms ion transport capability and specificity.

SUBMITTER: Jensen MW

PROVIDER: S-EPMC4339784 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Similar Datasets

Expression, purification, crystallization and preliminary X-ray analysis of the Met244Ala variant of catalase-peroxidase (KatG) from the haloarchaeon Haloarcula marismortui.

Project description:The covalent modification of the side chains of Trp95, Tyr218 and Met244 within the active site of Haloarcula marismortui catalase-peroxidase (KatG) appears to be common to all KatGs and has been demonstrated to be particularly significant for its bifunctionality [Smulevich et al. (2006), J. Inorg. Biochem. 100, 568-585; Jakopitsch, Kolarich et al. (2003), FEBS Lett. 552, 135-140; Jakopitsch, Auer et al. (2003), J. Biol. Chem. 278, 20185-20191; Jakopitsch et al. (2004), J. Biol. Chem. 279, 46082-46095; Regelsberger et al. (2001), Biochem. Soc. Trans. 29, 99-105; Ghiladi, Knudsen et al. (2005), J. Biol. Chem. 280, 22651-22663; Ghiladi, Medzihradzky et al. (2005), Biochemistry, 44, 15093-15105]. The Met244Ala variant of the H. marismortui KatG enzyme was expressed in haloarchaeal host cells and purified to homogeneity. The variant showed a complete loss of catalase activity, whereas the peroxidase activity of this mutant was highly enhanced owing to an increase in its affinity for the peroxidatic substrate. The variant was crystallized using the hanging-drop vapour-diffusion method with ammonium sulfate and NaCl as precipitants. The reddish-brown rod-shaped crystals obtained belong to the monoclinic space group C2, with unit-cell parameters a = 315.24, b = 81.04, c = 74.77 A, beta = 99.81 degrees . A crystal frozen using lithium sulfate as the cryoprotectant diffracted to beyond 2.0 A resolution. Preliminary X-ray analysis suggests the presence of a dimer in the asymmetric unit.

| S-EPMC2339759 | biostudies-literature

Haloarcula marismortui

Project description:Halophilic archaeon

| PRJNA35207 | ENA

Salt-dependent regulation of archaellins in Haloarcula marismortui.

Project description:Microorganisms require a motility structure to move towards optimal growth conditions. The motility structure from archaea, the archaellum, is fundamentally different from its bacterial counterpart, the flagellum, and is assembled in a similar fashion as type IV pili. The archaellum filament consists of thousands of copies of N-terminally processed archaellin proteins. Several archaea, such as the euryarchaeon Haloarcula marismortui, encode multiple archaellins. Two archaellins of H. marismortui display differential stability under various ionic strengths. This suggests that these proteins behave as ecoparalogs and perform the same function under different environmental conditions. Here, we explored this intriguing system to study the differential regulation of these ecoparalogous archaellins by monitoring their transcription, translation, and assembly into filaments. The salt concentration of the growth medium induced differential expression of the two archaellins. In addition, this analysis indicated that archaellation in H. marismortui is majorly regulated on the level of secretion, by a still unknown mechanism. These findings indicate that in archaea, multiple encoded archaellins are not completely redundant, but in fact can display subtle functional differences, which enable cells to cope with varying environmental conditions.

| S-EPMC6528647 | biostudies-literature

Novel xylose dehydrogenase in the halophilic archaeon Haloarcula marismortui.

Project description:During growth of the halophilic archaeon Haloarcula marismortui on D-xylose, a specific D-xylose dehydrogenase was induced. The enzyme was purified to homogeneity. It constitutes a homotetramer of about 175 kDa and catalyzed the oxidation of xylose with both NADP+ and NAD+ as cosubstrates with 10-fold higher affinity for NADP+. In addition to D-xylose, D-ribose was oxidized at similar kinetic constants, whereas D-glucose was used with about 70-fold lower catalytic efficiency (kcat/Km). With the N-terminal amino acid sequence of the subunit, an open reading frame (ORF)-coding for a 39.9-kDA protein-was identified in the partially sequenced genome of H. marismortui. The function of the ORF as the gene designated xdh and coding for xylose dehydrogenase was proven by its functional overexpression in Escherichia coli. The recombinant enzyme was reactivated from inclusion bodies following solubilization in urea and refolding in the presence of salts, reduced and oxidized glutathione, and substrates. Xylose dehydrogenase showed the highest sequence similarity to glucose-fructose oxidoreductase from Zymomonas mobilis and other putative bacterial and archaeal oxidoreductases. Activities of xylose isomerase and xylulose kinase, the initial reactions of xylose catabolism of most bacteria, could not be detected in xylose-grown cells of H. marismortui, and the genes that encode them, xylA and xylB, were not found in the genome of H. marismortui. Thus, we propose that this first characterized archaeal xylose dehydrogenase catalyzes the initial step in xylose degradation by H. marismortui.

| S-EPMC515137 | biostudies-literature

Genome sequence of Haloarcula marismortui: a halophilic archaeon from the Dead Sea.

Project description:We report the complete sequence of the 4,274,642-bp genome of Haloarcula marismortui, a halophilic archaeal isolate from the Dead Sea. The genome is organized into nine circular replicons of varying G+C compositions ranging from 54% to 62%. Comparison of the genome architectures of Halobacterium sp. NRC-1 and H. marismortui suggests a common ancestor for the two organisms and a genome of significantly reduced size in the former. Both of these halophilic archaea use the same strategy of high surface negative charge of folded proteins as means to circumvent the salting-out phenomenon in a hypersaline cytoplasm. A multitiered annotation approach, including primary sequence similarities, protein family signatures, structure prediction, and a protein function association network, has assigned putative functions for at least 58% of the 4242 predicted proteins, a far larger number than is usually achieved in most newly sequenced microorganisms. Among these assigned functions were genes encoding six opsins, 19 MCP and/or HAMP domain signal transducers, and an unusually large number of environmental response regulators-nearly five times as many as those encoded in Halobacterium sp. NRC-1--suggesting H. marismortui is significantly more physiologically capable of exploiting diverse environments. In comparing the physiologies of the two halophilic archaea, in addition to the expected extensive similarity, we discovered several differences in their metabolic strategies and physiological responses such as distinct pathways for arginine breakdown in each halophile. Finally, as expected from the larger genome, H. marismortui encodes many more functions and seems to have fewer nutritional requirements for survival than does Halobacterium sp. NRC-1.

| S-EPMC525680 | biostudies-literature

Methylomes of Two Extremely Halophilic Archaea Species, Haloarcula marismortui and Haloferax mediterranei.

Project description:The genomes of two extremely halophilic Archaea species, Haloarcula marismortui and Haloferax mediterranei, were sequenced using single-molecule real-time sequencing. The ∼4-Mbp genomes are GC rich with multiple large plasmids and two 4-methyl-cytosine patterns. Methyl transferases were incorporated into the Restriction Enzymes Database (REBASE), and gene annotation was incorporated into the Haloarchaeal Genomes Database (HaloWeb).

| S-EPMC6606915 | biostudies-literature

Transcription analysis of two disparate rRNA operons in the halophilic archaeon Haloarcula marismortui.

Project description:The genome of the halophilic archaeon Haloarcula marismortui contains two rRNA operons designated rrnA and rrnB. Genomic clones of the two operons and their flanking regions have been sequenced, and primary transcripts and processing intermediates derived from each operon have been characterized. The 16S, 23S, and 5S genes from the two operons were found to differ at 74 of 1,472 positions, 39 of 2,922 positions, and 2 of 122 positions, respectively. This degree of sequence divergence for multicopy (paralogous) rRNA genes was 10- to 50-fold or more higher than anticipated. The two operons exhibit other profound differences that include (i) the presence in rrnA and the absence in rrnB of tRNAAla and tRNACys genes in the intergenic and distal regions, respectively, (ii) divergent 5' flanking sequences, and (iii) distinct pathways for processing and maturation of 16S rRNA. Processing and maturation of 16S and 23S rRNA from rrnA operon transcripts and of 23S rRNA from rrnB operon transcripts follow the canonical halophilic pathway, whereas maturation of 16S rRNA from rrnB operon transcripts follows an unusual and different pathway that is apparently devoid of any 5' processing intermediate.

| S-EPMC107503 | biostudies-literature

Response of extreme haloarchaeon Haloarcula argentinensis RR10 to simulated microgravity in clinorotation.

Project description:Gravity is the fundamental force that may have operated during the evolution of life on Earth. It is thus important to understand as to what the effects of gravity are on cellular life. The studies related to effect of microgravity on cells may provide greater insights in understanding of how the physical force of gravity shaped life on Earth. The present study focuses on a unique group of organisms called the Haloarchaea, which are known for their extreme resistance to survive in stress-induced environments. The aim of the present investigation was to study the effect of simulated microgravity on physiological response of extremely halophilic archaeon, Haloarcula argentinensis RR10, under slow clinorotation. The growth kinetics of the archaeon in microgravity was studied using the Baryani model and the viable and apoptotic cells were assessed using propidium iodide fluorescent microscopic studies. The physiological mechanism of adaptation was activation of 'salt-in' strategy by intracellular sequestration of sodium ions as detected by EDAX. The organism upregulated the production of ribosomal proteins in simulated microgravity as evidenced by Matrix-assisted laser desorption ionization Time of flight-Mass Spectrophotometry. Simulated microgravity altered the antibiotic susceptibility of the haloarchaeon and it developed resistance to Augmentin, Norfloxacin, Tobramycin and Cefoperazone, rendering it a multidrug resistant strain. The presence of antibiotic efflux pump was detected in the haloarchaeon and it also enhanced production of protective carotenoid pigment in simulated microgravity. The present study is presumably the first report of physiological response of H. argentinensis RR10 in microgravity simulated under slow clinorotation.

| S-EPMC5388653 | biostudies-literature

Biology and survival of extremely halophilic archaeon Haloarcula marismortui RR12 isolated from Mumbai salterns, India in response to salinity stress.

Project description:Haloarchaea are unique microorganism's resistant to environmental and osmotic stresses and thrive in their habitats despite extreme fluctuating salinities. In the present study, haloarchaea were isolated from hypersaline thalossohaline salterns of Bhandup, Mumbai, India and were identified as Haloferax prahovense, Haloferax alexandrines, Haloferax lucentense, Haloarcula tradensis, Haloarcula marismortui and Haloarcula argentinensis. The mechanism of adaptation to contrasting salinities (1.5 M and 4.5 M) was investigated in the extreme haloarchaeon, Hal. marismortui RR12. Hal. marismortui RR12 increased the intracellular sequestration of K(+) and Cl(-) ions in hypo salinity and hyper salinity respectively as detected by Energy-dispersive X-ray spectroscopy microanalysis (EDAX) and Inductively Coupled Plasma- atomic Emission Spectroscopy (ICP-AES) indicating the presence of 'salt-in' strategy of osmoadaptation. As a cellular response to salinity stress, it produced small heat shock like proteins (sHSP) identified using MALDI-TOF MS and increased the production of protective red carotenoid pigment. This is the first report on the study of the concomitant cellular, molecular and physiological mechanism adapted by Hal. marismortui RR12 when exposed to contrasting salinities in external environment.

| S-EPMC4882750 | biostudies-literature

Haloarcula marismortui ATCC 43049

Project description:Chemoheterotrophic obligate extreme halophilic archeon

| PRJNA105 | ENA