-
Molecular Biology Research... Mar 2014The histone-like protein HU is the most-abundant DNA-binding protein in bacteria. The HU protein non-specifically binds and bends DNA as a hetero- or homodimer, and can...
The histone-like protein HU is the most-abundant DNA-binding protein in bacteria. The HU protein non-specifically binds and bends DNA as a hetero- or homodimer, and can participate in DNA supercoiling and DNA condensation. It also takes part in DNA functions such as replication, recombination, and repair. HU does not recognize any specific sequences but shows a certain degree of specificity to cruciform DNA and repair intermediates such as nick, gap, bulge, etc. To understand the features of HU binding to DNA and repair intermediates, a fast and easy HU protein purification method is required. Here we report a two-step purification procedure of HU from (the gram positive and moderately halophilic bacteria isolated from Karaj surface soil). The method of HU purification allows obtaining a pure non-tagged protein. Salting out and ion exchange chromatography were applied for purification, and the purified protein was identified by immunoblotting. Results showed that the molecular weight of the purified protein was approximately 11 kDa which is immunologically similar to the HU protein (HBsu).
PubMed: 27843972
DOI: No ID Found -
Brazilian Journal of Microbiology :... Oct 2012Halophiles are excellent sources of enzymes that are not only salt stable but also can withstand and carry out reactions efficiently under extreme conditions. The aim of...
Halophiles are excellent sources of enzymes that are not only salt stable but also can withstand and carry out reactions efficiently under extreme conditions. The aim of the study was to isolate and study the diversity among halophilic bacteria producing enzymes of industrial value. Screening of halophiles from various saline habitats of India led to isolation of 108 halophilic bacteria producing industrially important hydrolases (amylases, lipases and proteases). Characterization of 21 potential isolates by morphological, biochemical and 16S rRNA gene analysis found them related to Marinobacter, Virgibacillus, Halobacillus, Geomicrobium, Chromohalobacter, Oceanobacillus, Bacillus, Halomonas and Staphylococcus genera. They belonged to moderately halophilic group of bacteria exhibiting salt requirement in the range of 3-20%. There is significant diversity among halophiles from saline habitats of India. Preliminary characterization of crude hydrolases established them to be active and stable under more than one extreme condition of high salt, pH, temperature and presence of organic solvents. It is concluded that these halophilic isolates are not only diverse in phylogeny but also in their enzyme characteristics. Their enzymes may be potentially useful for catalysis under harsh operational conditions encountered in industrial processes. The solvent stability among halophilic enzymes seems a generic novel feature making them potentially useful in non-aqueous enzymology.
PubMed: 24031991
DOI: 10.1590/S1517-838220120004000044 -
Applied and Environmental Microbiology Jun 2013In their natural environments, moderately halophilic bacteria are confronted not only with high salinities but also with low oxygen tensions due to the high salinities....
In their natural environments, moderately halophilic bacteria are confronted not only with high salinities but also with low oxygen tensions due to the high salinities. The growth of H. halophilus is strictly aerobic. To analyze the dependence of respiration on the NaCl concentration and oxygen availability of the medium, resting cell experiments were performed. The respiration rates were dependent on the NaCl concentration of the growth medium, as well as on the NaCl concentration of the assay buffer, indicating regulation on the transcriptional and the activity level. Respiration was accompanied by the generation of an electrochemical proton potential (Δμ(H+)) across the cytoplasmic membrane whose magnitude was dependent on the external pH. Genes encoding proteins involved in respiration and Δμ(H+) generation, such as a noncoupled NADH dehydrogenase (NDH-2), complex II, and complex III, were identified in the genome. In addition, genes encoding five different terminal oxidases are present. Inhibitor profiling revealed the presence of NDH-2 and complex III, but the nature of the oxidases could not be resolved using this approach. Expression analysis demonstrated that all the different terminal oxidases were indeed expressed, but by far the most prominent was cta, encoding cytochrome caa3 oxidase. The expression of all of the different oxidase genes increased at high NaCl concentrations, and the transcript levels of cta and qox (encoding cytochrome aa3 oxidase) also increased at low oxygen concentrations. These data culminate in a model of the composition and variation of the respiratory chain of H. halophilus.
Topics: Adenosine Triphosphate; Cell Membrane; Electron Transport; Energy Metabolism; Halobacillus; Hydrogen-Ion Concentration; Oxygen; Proton-Motive Force; Real-Time Polymerase Chain Reaction; Salinity
PubMed: 23584768
DOI: 10.1128/AEM.00855-13 -
Genome Announcements Jan 2013The sp. strain BAB-2008 is a moderately halophilic, rod-shaped, Gram-positive, orange-pigmented, carotenoid-producing bacterium isolated from saline soil near...
The sp. strain BAB-2008 is a moderately halophilic, rod-shaped, Gram-positive, orange-pigmented, carotenoid-producing bacterium isolated from saline soil near Zazam-Solar Park Road, Gujarat, India. Here we present the 3.7-Mb genome sequence to provide insights into its functional genomics and potential applications for carotenoid and enzyme production.
PubMed: 23469348
DOI: 10.1128/genomeA.00222-12 -
Life (Basel, Switzerland) Feb 2013The capability of osmoadaptation is a prerequisite of organisms that live in an environment with changing salinities. Halobacillus halophilus is a moderately halophilic... (Review)
Review
The capability of osmoadaptation is a prerequisite of organisms that live in an environment with changing salinities. Halobacillus halophilus is a moderately halophilic bacterium that grows between 0.4 and 3 M NaCl by accumulating both chloride and compatible solutes as osmolytes. Chloride is absolutely essential for growth and, moreover, was shown to modulate gene expression and activity of enzymes involved in osmoadaptation. The synthesis of different compatible solutes is strictly salinity- and growth phase-dependent. This unique hybrid strategy of H. halophilus will be reviewed here taking into account the recently published genome sequence. Based on identified genes we will speculate about possible scenarios of the synthesis of compatible solutes and the uptake of potassium ion which would complete our knowledge of the fine-tuned osmoregulation and intracellular osmolyte balance in H. halophilus.
PubMed: 25371341
DOI: 10.3390/life3010234 -
Biochimica Et Biophysica Acta Mar 2013NhaH is a novel Na(+)/H(+) antiporter identified from the moderate halophile Halobacillus dabanensis. In this study, six conserved charged residues located in the...
NhaH is a novel Na(+)/H(+) antiporter identified from the moderate halophile Halobacillus dabanensis. In this study, six conserved charged residues located in the putative transmembrane segments (TMS) including TMSV, TMSVI, TMSVIII and TMSXI of NhaH as well as two His residues in Loop III were replaced by site-directed mutagenesis for the identification of their potential roles in the antiport activity and pH regulation. Substitutions D137A, D166A and R325A caused a complete loss of Na(+)(Li(+))/H(+) antiport activity, revealing that D137, D166 and R325 are indispensable for the antiport activity. Substitution D137E led to a significant increase of the apparent Km values for Na(+) and Li(+) without affecting the changes of pH profile, confirming that D137 plays vital roles in alkali cation binding/translocation. Substitution D166E resulted in not only a significant increase of the apparent Km values for Na(+) and Li(+) but also an alkaline shift of pH profile, suggesting that D166 is involved in alkali cation binding/translocation as well as H(+) binding or pH regulation. Substitutions E161N, D224A and D224E caused a significant increase of Km for Na(+) and Li(+), indicating that E161 and D224 partly contribute to alkali cation binding/translocation. Substitution E229K caused an over 50% elevation of the apparent Km for Li(+), without affecting that for Na(+), suggesting that E229 may be mainly responsible for Li(+) binding/translocation. Substitutions H87A and H88A resulted in an acidic shift of pH profile without an effect on Km for Na(+) and Li(+), indicating that H87 and H88 are involved in H(+) binding or pH regulation.
Topics: Amino Acid Sequence; Antiporters; Bacterial Proteins; Base Sequence; Cations; Cell Membrane; Cloning, Molecular; DNA; Halobacillus; Hydrogen-Ion Concentration; Kinetics; Lithium; Molecular Sequence Data; Mutagenesis, Site-Directed; Protein Binding; Protein Transport; Sequence Homology, Amino Acid; Sodium; Sodium-Hydrogen Exchangers
PubMed: 23196349
DOI: 10.1016/j.bbamem.2012.11.015 -
Journal of Applied Microbiology Sep 2012To isolate and characterize the cultivable community of hydrolase producers (amylase, protease, lipase, DNase, xylanase and pullulanase) inhabiting...
Analysis and characterization of cultivable extremophilic hydrolytic bacterial community in heavy-metal-contaminated soils from the Atacama Desert and their biotechnological potentials.
AIMS
To isolate and characterize the cultivable community of hydrolase producers (amylase, protease, lipase, DNase, xylanase and pullulanase) inhabiting heavy-metal-contaminated soils in extreme conditions from the Atacama Desert.
METHODS AND RESULTS
A total of 25 bacterial strains showing hydrolytic activities have been selected including halotolerants, extremely halotolerants and moderate halophiles. Most hydrolase producers were assigned to the family B acillaceae, belonging to the genera Bacillus (nine strains), Halobacillus (seven strains) and Thalassobacillus (five strains) and four isolates were related to members of the families Pseudomonadaceae, Halomonadaceae and Staphylococcaceae. The selected strains were then characterized for their tolerance pattern to six heavy metals, measured as minimal inhibitory concentrations (MICs).
CONCLUSIONS
The diversity found in the cultivable bacterial community analysed is more limited than that detected in other ecological studies owing to the restrictive conditions used in the screening. The dominant bacteria were Firmicutes and particularly, species related to the genus Bacillus.
SIGNIFICANCE AND IMPACT OF THE STUDY
This study is focused on the characterization of extremophilic hydrolytic bacteria, providing candidates as a source of novel enzymes with biotechnological applications.
Topics: Bacillus; Bacteria; Chile; DNA, Bacterial; Desert Climate; Hydrolases; Metals, Heavy; Phylogeny; RNA, Ribosomal, 16S; Sequence Analysis, DNA; Soil Microbiology; Soil Pollutants
PubMed: 22716924
DOI: 10.1111/j.1365-2672.2012.05366.x -
Astrobiology Feb 2012The martian surface environment exhibits extremes of salinity, temperature, desiccation, and radiation that would make it difficult for terrestrial microbes to survive....
The martian surface environment exhibits extremes of salinity, temperature, desiccation, and radiation that would make it difficult for terrestrial microbes to survive. Recent evidence suggests that martian soils contain high concentrations of MgSO₄ minerals. Through warming of the soils, meltwater derived from subterranean ice-rich regolith may exist for an extended period of time and thus allow the propagation of terrestrial microbes and create significant bioburden at the near surface of Mars. The current report demonstrates that halotolerant bacteria from the Great Salt Plains (GSP) of Oklahoma are capable of growing at high concentrations of MgSO₄ in the form of 2 M solutions of epsomite. The epsotolerance of isolates in the GSP bacterial collection was determined, with 35% growing at 2 M MgSO₄. There was a complex physiological response to mixtures of MgSO₄ and NaCl coupled with other environmental stressors. Growth also was measured at 1 M concentrations of other magnesium and sulfate salts. The complex responses may be partially explained by the pattern of chaotropicity observed for high-salt solutions as measured by agar gelation temperature. Select isolates could grow at the high salt concentrations and low temperatures found on Mars. Survival during repetitive freeze-thaw or drying-rewetting cycles was used as other measures of potential success on the martian surface. Our results indicate that terrestrial microbes might survive under the high-salt, low-temperature, anaerobic conditions on Mars and present significant potential for forward contamination. Stringent planetary protection requirements are needed for future life-detection missions to Mars.
Topics: Freezing; Halobacillus; Halomonas; Magnesium Sulfate; Mars; Oklahoma; Salinity; Stress, Physiological
PubMed: 22248384
DOI: 10.1089/ast.2011.0720 -
Research in Microbiology 2010Extremophilic prokaryotes inhabit ecosystems that are, from a human perspective, extreme, and life in these environments requires far-reaching cellular adaptations.... (Review)
Review
Extremophilic prokaryotes inhabit ecosystems that are, from a human perspective, extreme, and life in these environments requires far-reaching cellular adaptations. Here, we will describe, for two examples (Thermus thermophilus, Halobacillus halophilus), how thermophilic or halophilic bacteria adapt to their environment; we will describe the molecular basis of sensing and responding to hypersalinity and we will analyze the impact and basis of natural competence for survival in hot environments.
Topics: Adaptation, Physiological; Environmental Microbiology; Halobacteriaceae; Halobacteriales; Hot Temperature; Salt Tolerance; Thermus thermophilus
PubMed: 20594981
DOI: 10.1016/j.resmic.2010.05.006 -
International Journal of Microbiology 2009Bacterial and archaeal aerobic communities were recovered from sediments from the shallow El-Djerid salt lake in Tunisia, and their salinity gradient distribution was...
Bacterial and archaeal aerobic communities were recovered from sediments from the shallow El-Djerid salt lake in Tunisia, and their salinity gradient distribution was established. Six samples for physicochemical and microbiological analyses were obtained from 6 saline sites in the lake for physico-chemical and microbiological analyses. All samples studied were considered hypersaline with NaCl concentration ranging from 150 to 260 g/L. A specific halophilic microbial community was recovered from each site, and characterization of isolated microorganisms was performed via both phenotypic and phylogenetic approaches. Only one extreme halophilic organism, domain Archaea, was isolated from site 4 only, whereas organisms in the domain Bacteria were recovered from the five remaining sampling sites that contained up to 250 g/L NaCl. Members of the domain Bacteria belonged to genera Salicola, Pontibacillus, Halomonas, Marinococcus, and Halobacillus, whereas the only member of domain Archaea isolated belonged to the genus Halorubrum. The results of this study are discussed in terms of the ecological significance of these microorganisms in the breakdown of organic matter in Lake El-Djerid and their potential for industry applications.
PubMed: 20066169
DOI: 10.1155/2009/731786