-
The Science of the Total Environment Jul 2018The use of plant associated, indigenous beneficial microbes for sustainable agriculture is getting worldwide acceptance as they successfully colonize at different plant...
Characterization of halotolerant, pigmented, plant growth promoting bacteria of groundnut rhizosphere and its in-vitro evaluation of plant-microbe protocooperation to withstand salinity and metal stress.
The use of plant associated, indigenous beneficial microbes for sustainable agriculture is getting worldwide acceptance as they successfully colonize at different plant niche under stress conditions to enhance the crop productivity. They also generate several plant growth regulators and protect plants from adversity like presence of salts and metals. In the present study, indigenous, halotolerant, plant growth promoting (PGP) bacterial isolates were isolated from the saline rhizospheric soil of groundnut plants aiming to investigate its in-vitro metal remediation capabilities under saline stress condition. Two pigmented bacteria were selected based on their phenotypic, biochemical, physiological and PGP characters and identified as members of family Bacillaceae (Bacillus and Halobacillus) based on 16S rRNA gene sequence similarity. The pigments were extracted, tested for different antioxidant properties and identified by GC-MS and FT-IR spectra. Simultaneously, both strains exhibited a wide range of salinity (NaCl≥25%), metal resistance (Zinc≈1700mgkg, Aluminium≈1800mgkg, Lead≈1800mgkg), pH (6-10), PGP attributes (indole - 1.05-3.15μgml, ammonia - 0.13-19.95mmolml, nitrite - 0.07-0.26mmolml) and antibiotics sensitivity revealing their wide range of metabolic diversity. In-vitro inoculation of groundnut seedlings with selected isolates under salinity (1% NaCl) and metal (Zn, Al and Pb) stress had a positive impact on different plant physiological parameters (lesser lignification, intact proto xylem and cortical parenchyma) which was correlated with PGP attributes. Microwave plasma atomic emission spectroscopy analysis of seedling samples also detected less amount of metals in plants treated with bacteria indicating, an establishment of plant-microbe protocooperation to withstand salinity and metal stress. This strategy can be implemented to improve crop production in saline metal polluted agriculture fields.
Topics: Bacteria; Metals; Nuts; Plant Development; Rhizosphere; Salinity; Salt Tolerance; Soil; Soil Microbiology; Soil Pollutants; Symbiosis
PubMed: 29482138
DOI: 10.1016/j.scitotenv.2018.02.227 -
Current Microbiology Jul 2018Two strict halophilic bacterial strains, Halobacillus trueperi SS1, and Halobacillus trueperi SS3, and three halotolerant bacterial strains, Shewanella algae SS2,...
Two strict halophilic bacterial strains, Halobacillus trueperi SS1, and Halobacillus trueperi SS3, and three halotolerant bacterial strains, Shewanella algae SS2, Halomonas venusta SS5, and Marinomonas sp. SS8 of Lunsu salt water body, Himachal Pradesh, India, were selected to study the mechanism of salt tolerance and the role of osmolytes therein. A combination of flame photometry, chromatographic and colorimetric assays was used to study the mechanism of salt tolerance in the selected strict halophilic and halotolerant bacterial strains. The strict halophiles and, one of the halotolerants, Marinomonas sp. SS8 were found to utilize both "salt-in strategy" and "accumulation of compatible solutes strategy" for osmoregulation in hypersaline conditions. On the contrary, the remaining two halotolerants used "accumulation of compatible solutes strategy" under saline stress and not the "salt-in strategy". The present study suggests towards distinct mechanisms of salt tolerance in the two classes, wherein strict halophiles accumulate compatible solutes as well as adopt salt-in strategy, while the halotolerant bacteria accumulate a range of compatible solutes, except Marinomonas sp. SS8, which utilizes both the strategies to combat salt stress.
Topics: Adaptation, Physiological; Bacteria; India; Osmosis; Salt Tolerance; Sodium Chloride; Water; Water Microbiology
PubMed: 29480323
DOI: 10.1007/s00284-018-1462-8 -
3 Biotech Jan 2018This report describes cultivation-dependent diversity, phylogeny and enzymatic potential of the haloalkaliphilic bacteria isolated from the unvegetated desert soil of...
This report describes cultivation-dependent diversity, phylogeny and enzymatic potential of the haloalkaliphilic bacteria isolated from the unvegetated desert soil of yet unexplored, saline desert of Little Rann of Kutch (LRK), India. The LRK is a unique ecosystem displaying a combination of Dry Rann and Wet Rann. A total of 25 bacteria were isolated and characterized on the basis of colony morphology, biochemical profile, sugar utilization, secretion of the extracellular enzymes and antibiotic sensitivity. Further, the identification and phylogenetic relatedness of 23 bacteria were established by the analysis of 16S rRNA gene sequences. The phylogenetic analysis indicated that the isolates belong to the phylum , comprising low G + C, Gram-positive bacteria, with different genera: (~ 39%), (~ 30%), (~ 13%), (~ 13%), (~ 4%). Majority of the bacterial isolates produced proteases (30% isolates) followed by cellulases (24% isolates), CMCases (24% isolates) and amylases (20% isolates). , and predominantly produced hydrolases, while many produced multiple enzymes at high salinity and alkaline pH. Highest antibiotic resistance was observed against Ampicillin and Penicillin (32%) followed by Cefaclor (20%); Colistin, Cefoperazone and Cefotaxime (16%); Cefuroxime (12%); Gentamycin and Cefixime (8%); Erythromycin, Cefadroxil, Azithromycin, Co-trimoxazole, Amoxycillin, Norfloxacin, Cefpodoxime, Amikacin and Augmentin (4%). KJ1-10-99 and KJ1-10-93 representing < 97% of 16S rRNA gene sequence similarity belong to a novel lineage within the family . Comparison of the phenogram and phylogram revealed the contradiction of the phenogram pattern and the phylogenetic placement of the isolates. The isolates belonging to same species have shown considerable phenotypic variation. The study on the cultivable haloalkaliphilic bacteria of an unexplored enigmatic niche reflects ecological and biotechnological significance.
PubMed: 29354364
DOI: 10.1007/s13205-017-1075-0 -
Systematic and Applied Microbiology May 2018The bacterial community composition in the A horizon of a natural saline-alkaline soil located in Ararat Plain (Armenia) was studied using molecular and culture-based...
The bacterial community composition in the A horizon of a natural saline-alkaline soil located in Ararat Plain (Armenia) was studied using molecular and culture-based methods The sequence analysis of a 16S rRNA gene clone library and denaturing gradient gel electrophoresis (DGGE) profiles indicated dominance of Firmicutes populations. The majority of the sequences of the bacterial 16S rRNA gene library were close relatives of representatives belonging to the genera Halobacillus (41.2%), Piscibacillus (23.5%), Bacillus (23.5%) and Virgibacillus (11.8%). Eight novel moderately halophilic bacilli isolates were successfully obtained from the enriched cultures of the saline-alkaline soil samples. 16S rRNA gene sequence analyses of isolates revealed their affiliation (97.7-99.7% similarity) to representatives of the genera Bacillus, Piscibacillus and Halobacillus. All isolates were able to tolerate high concentrations of NaCl and highly alkaline conditions. This is the first study combining cultivation-independent and -dependent approaches to reveal the bacterial diversity of the saline-alkaline soils of Ararat Plain and it suggested an important role of bacilli as key microbes in biogeochemical cycles of these environments.
Topics: Alkalies; Armenia; Bacteria; Biodiversity; DNA, Bacterial; DNA, Ribosomal; Denaturing Gradient Gel Electrophoresis; Microbial Consortia; Phylogeny; RNA, Ribosomal, 16S; Sequence Analysis, DNA; Soil; Soil Microbiology
PubMed: 29342414
DOI: 10.1016/j.syapm.2017.12.002 -
Frontiers in Microbiology 2017The aim of the study was to explore the halophile metabolome in building materials using untargeted metabolomics which allows for broad metabolome coverage. For this...
The aim of the study was to explore the halophile metabolome in building materials using untargeted metabolomics which allows for broad metabolome coverage. For this reason, we used high-performance liquid chromatography interfaced to high-resolution mass spectrometry (HPLC/HRMS). As an alternative to standard microscopy techniques, we introduced pioneering Coherent Anti-stokes Raman Scattering Microscopy (CARS) to non-invasively visualize microbial cells. Brick samples saturated with salt solution (KCl, NaCl (two salinity levels), MgSO, Mg(NO)), were inoculated with the mixture of preselected halophilic microorganisms, i.e., bacteria: , and yeast: and stored at 28°C and 80% relative humidity for a year. Metabolites were extracted directly from the brick samples and measured via HPLC/HRMS in both positive and negative ion modes. Overall, untargeted metabolomics allowed for discovering the interactions of halophilic microorganisms with buildings materials which together with CARS microscopy enabled us to elucidate the biodeterioration process caused by halophiles. We observed that halophile metabolome was differently affected by different salt solutions. Furthermore, we found indications for haloadaptive strategies and degradation of brick samples due to microbial pigment production as a salt stress response. Finally, we detected changes in lipid content related to changes in the structure of phospholipid bilayers and membrane fluidity.
PubMed: 29321766
DOI: 10.3389/fmicb.2017.02448 -
Peptides Mar 2018Members of the Bacillaceae family, including Bacillus spp., Brevibacillus spp., Paenibacillus spp., Aneurinibacillus sp., and Halobacillus sp., are an important source... (Review)
Review
Members of the Bacillaceae family, including Bacillus spp., Brevibacillus spp., Paenibacillus spp., Aneurinibacillus sp., and Halobacillus sp., are an important source of structurally diverse classes of short peptides of ∼ 30 residues or fewer possessing peculiar and rapid killing activity against various pathogens. Additionally, many have unique structures that enhance resistance to hydrolysis by proteases, and these are ideal therapeutic tools and potential alternatives to current antibiotics. The need for novel antibiotic lead compounds is urgent, and this review summarises 119 Bacillaceae compounds published since 2000, including 12 surfactin-like lipopeptides, 16 iturinic lipopeptides, fengycin C, 33 other cyclic lipopeptides, 26 linear lipopeptides, two thiopeptides, four 2,5-diketopiperazines, 20 typical cyclic peptides, and five standard linear peptides. The current and potential therapeutic applications of these peptides, including structure, antibacterial, antifungal, and antiviral activities, are discussed.
Topics: Animals; Anti-Bacterial Agents; Bacillaceae; Humans; Peptides
PubMed: 29269072
DOI: 10.1016/j.peptides.2017.12.018 -
Frontiers in Microbiology 2017, a moderately halophilic bacterium, accumulates a variety of compatible solutes including glycine betaine, glutamate, glutamine, proline, and ectoine to cope with...
, a moderately halophilic bacterium, accumulates a variety of compatible solutes including glycine betaine, glutamate, glutamine, proline, and ectoine to cope with osmotic stress. Non-targeted analysis of intracellular organic compounds using H-NMR showed that a large amount of trans-4-hydroxy-L-proline (Hyp), which has not been reported as a compatible solute in , was accumulated in response to high NaCl salinity, suggesting that Hyp may be an important compatible solute in . Candidate genes encoding proline 4-hydroxylase (PH-4), which hydroxylates L-proline to generate Hyp, were retrieved from the genome of through domain searches based on the sequences of known PH-4 proteins. A gene, HBHAL_RS11735, which was annotated as a multidrug DMT transporter permease in GenBank, was identified as the PH-4 gene through protein expression analysis in . The PH-4 gene constituted a transcriptional unit with a promoter and a rho-independent terminator, and it was distantly located from the proline biosynthetic gene cluster ( operon). Transcriptional analysis showed that PH-4 gene expression was NaCl concentration-dependent, and was specifically induced by chloride anion, similar to the operon. Accumulation of intracellular Hyp was also observed in other bacteria, suggesting that Hyp may be a widespread compatible solute in halophilic and halotolerant bacteria.
PubMed: 29104571
DOI: 10.3389/fmicb.2017.02054 -
Genomics Data Dec 2017The draft genome sequence of the halophilic bacterium KTB 131, isolated from Topan salt of the Jeon-nam in Korea, was established. The genome comprises 4,151,649 bp,...
The draft genome sequence of the halophilic bacterium KTB 131, isolated from Topan salt of the Jeon-nam in Korea, was established. The genome comprises 4,151,649 bp, with a G + C content of 41.6%. The strain displays a high number of genes responsible for secondary metabolite biosynthesis, transport, and catabolism compared to other bacterial genus members. Numerous genes responsible for various transport systems, solute accumulation, and aromatic/sulfur decomposition were detected. The first genomic analysis encourages further research on comparative genomics and potential biotechnological applications. The whole draft genome sequence of KTB 131 is now available (Bioproject PRJNA380285).
PubMed: 28831380
DOI: 10.1016/j.gdata.2017.07.010 -
Microbes and Environments Jun 2017The aim of the present study was to obtain insights into the relationship between the chemical (salt content and pH) and physico-mechanical (humidity and compressive...
The aim of the present study was to obtain insights into the relationship between the chemical (salt content and pH) and physico-mechanical (humidity and compressive strength) properties of mineral-based materials from historic buildings with salt efflorescence and the growth and biodiversity of halophilic microorganisms. Samples were mainly characterized by pH 6.5-8.5 and a moisture content of between 0.12 and 3.3%. Significant variations were also found in the salt content (sulfates, chlorides, and nitrates) of the materials. An SEM/EDS analysis of material surfaces revealed the presence of halite, calcite, gypsum, sodium sulfate, and potassium-sodium sulfate. Culture-dependent and culture-independent (clone library construction) approaches were both applied to detect halophilic microorganisms. Results derived from culturable methods and the materials analysis revealed a correlation between the total halophile count and pH value as well as sulfate content. A correlation was not observed between the concentration of chlorides or nitrates and the number of halophilic microorganisms. The materials studied were inhabited by the culturable halophilic bacteria Halobacillus sp., Virgibacillus sp., and Marinococcus sp. as well as the yeast Sterigmatomyces sp., which was isolated for the first time from mineral materials. Culture-independent techniques revealed the following bacterial species: Salinibacterium, Salinisphaera, Rubrobacter, Rubricoccus, Halomonas, Halorhodospira, Solirubrobacter, Salinicoccus, and Salinibacter. Biodiversity was the highest in materials with high or moderate salinity.
Topics: Bacteria; Biodiversity; Compressive Strength; Construction Materials; Humidity; Hydrogen-Ion Concentration; Salts
PubMed: 28592721
DOI: 10.1264/jsme2.ME16159 -
Scientific Reports Apr 2017In this study, genomic DNA was screened from Halobacillus andaensis NEAU-ST10-40 by selection in Escherichia coli KNabc lacking three major Na/H antiporters. One gene...
In this study, genomic DNA was screened from Halobacillus andaensis NEAU-ST10-40 by selection in Escherichia coli KNabc lacking three major Na/H antiporters. One gene designated upf0118 exhibiting Na(Li)/H antiport activity was finally cloned. Protein alignment showed that UPF0118 shares the highest identity of 81.5% with an unannotated gene encoding a protein with uncharacterized protein function belonging to UPF0118 family from H. kuroshimensis, but shares no identity with all known specific Na(Li)/H antiporter genes or genes with Na(Li)/H antiport activity. Growth test, western blot and Na(Li)/H antiport assay revealed that UPF0118 as a transmembrane protein exhibits pH-dependent Na(Li)/H antiport activity. Phylogenetic analysis indicated that UPF0118 clustered with all its homologs belonging to UPF0118 family at a wide range of 22-82% identities with the bootstrap value of 92%, which was significantly distant with all known specific single-gene Na(Li)/H antiporters and single-gene proteins with the Na(Li)/H antiport activity. Taken together, we propose that UPF0118 should represent a novel class of Na(Li)/H antiporter. To the best of our knowledge, this is the first report on the functional analysis of a protein with uncharacterized protein function as a representative of UPF0118 family containing the domain of unknown function, DUF20.
Topics: Amino Acid Sequence; Antiporters; Bacterial Proteins; Base Sequence; Cloning, Molecular; Halobacillus; Hydrogen-Ion Concentration; Ion Transport; Lithium; Membrane Proteins; Phylogeny; Sequence Analysis, DNA; Sequence Homology, Amino Acid; Sodium; Sodium-Hydrogen Exchangers
PubMed: 28374790
DOI: 10.1038/srep45936