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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 -
Plants (Basel, Switzerland) Jun 2024Bacterial endophytes (120) were isolated from six halophytes (, , , , , and ). These halophiles were molecularly identified and characterized with or without NaCl...
Bacterial endophytes (120) were isolated from six halophytes (, , , , , and ). These halophiles were molecularly identified and characterized with or without NaCl conditions. Characterization was based on tests such as indole acetic acid (IAA), exopolysaccharides (EPS), and siderophores (SID) production; solubilization of phosphate (P), potassium (K), zinc (Zn), and manganese (Mn); mineralization of phytate; enzymatic activity (acid and alkaline phosphatase, phytases, xylanases, and chitinases) and the mineralization/solubilization mechanisms involved (organic acids and sugars). Moreover, compatibility among bacteria was assessed. Eleven halophiles were characterized as highly tolerant to NaCl (2.5 M). The bacteria isolated were all different from each other. Two belonged to and one to while the rest of bacteria were identified up to the genus level as belonging to , , and three strains of The biochemical responses of nutrient solubilization and enzymatic activity were different between bacteria and were influenced by the presence of NaCl. Organic acids were involved in P mineralization and nutrient solubilization. Tartaric acid was common in the solubilization of P, Zn, and K. Maleic and vanillic acid were only detected in Zn and K solubilization, respectively. Furthermore, sugars appeared to be involved in the solubilization of nutrients; fructose was detected in the solubilization tests. Therefore, these biochemical bacterial characteristics should be corroborated in vivo and tested as a consortium to mitigate saline stress in glycophytes under a global climate change scheme that threatens to exacerbate soil salinity.
PubMed: 38931058
DOI: 10.3390/plants13121626 -
Environmental Microbiome Mar 2023The adaptability of halophytes to increased soil salinity is related to complex rhizosphere interactions. In this study, an integrative approach, combining...
The adaptability of halophytes to increased soil salinity is related to complex rhizosphere interactions. In this study, an integrative approach, combining culture-independent and culture-dependent techniques was used to analyze the bacterial communities in the endorizosphere of indigenous succulent halophytes Salicornia europaea, Suaeda maritima, and Camphorosma annua from the natural salt marshes of Slano Kopovo (Serbia). The 16 S rDNA analyses gave, for the first time, an insight into the composition of the endophytic bacterial communities of S. maritima and C. annua. We have found that the composition of endophyte microbiomes in the same habitat is to some extent influenced by plant species. A cultivable portion of the halophyte microbiota was tested at different NaCl concentrations for the set of plant growth promoting (PGP) traits. Through the mining of indigenous halotolerant endophytes, we obtained a collection representing a core endophyte microbiome conferring desirable PGP traits. The majority (65%) of the selected strains belonged to the common halotolerant/halophilic genera Halomonas, Kushneria, and Halobacillus, with representatives exhibiting multiple PGP traits, and retaining beneficial traits in conditions of the increased salinity. The results suggest that the root endosphere of halophytes is a valuable source of PGP bacteria supporting plant growth and fitness in salt-affected soils.
PubMed: 36934265
DOI: 10.1186/s40793-023-00477-x -
New Microbes and New Infections Sep 2020Strain Marseille-Q1234 is a new species from the genus that was isolated in 2019 from a stool sample in a healthy Malian child <5 years old. Cells are Gram-positive and...
Strain Marseille-Q1234 is a new species from the genus that was isolated in 2019 from a stool sample in a healthy Malian child <5 years old. Cells are Gram-positive and strictly halophilic bacilli. Strain Marseille-Q1234 exhibits 98.46% 16S rRNA gene sequence similarity to strain JSM 071068 (NR_116505.1), the phylogenetically closely related species with standing in nomenclature. Based on the phenotypic and phylogenetic evidence, OrthoANI values and results of the biochemical tests, the new species is named sp. nov., for which strain Marseille-Q1234 (= CSURQ1234) is proposed as the type strain.
PubMed: 32793353
DOI: 10.1016/j.nmni.2020.100708 -
Heliyon Nov 2018Cultivable halophilic microorganisms were isolated and identified from saline and alkaline-sodic soils: Cuatro Cienegas, Sayula and San Marcos lakes. Physicochemical...
Cultivable halophilic microorganisms were isolated and identified from saline and alkaline-sodic soils: Cuatro Cienegas, Sayula and San Marcos lakes. Physicochemical characteristics of soils were determined to understand the relationship between those and the microorganisms isolated. The Cuatro Cienegas soils had a neutral pH, EC of 2.3-8 dS cm, classified as moderately saline. Whereas, the soils from Sayula and San Marcos lakes, had an alkaline pH, EC 15 to 65 dS m, typical of saline-sodic. We identified 23 cultivable halophilic bacteria using 16s rDNA, being sp., sp., and sp. the predominant genus by culture dependent approach. We found a correlation between the soils anion and cation content with the occurrence of different genus of halophilic bacteria in each studied site. sp. was predominant in Sayula and San Marcos lakes and was related to the high Na content; while sp. and sp. were predominant in Cuatro Cienegas, their occurrence was related to a high content of Ca, Mg, and SO .
PubMed: 30519656
DOI: 10.1016/j.heliyon.2018.e00954 -
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 -
Brazilian Journal of Microbiology :... Jan 2019Microbes from hypersaline environments are useful in biotechnology as sources of novel enzymes and proteins. The current study aimed to characterize halophilic bacteria...
Microbes from hypersaline environments are useful in biotechnology as sources of novel enzymes and proteins. The current study aimed to characterize halophilic bacteria from the rhizosphere of halophytes (Salsola stocksii and Atriplex amnicola), non-rhizospheric, and brine lake-bank soils collected from Khewra Salt Mine and screening of these bacterial strains for industrially important enzymes. A total of 45 bacterial isolates from the rhizosphere of Salsola, 38 isolates from Atriplex, 24 isolates from non-rhizospheric, and 25 isolates from lake-bank soils were identified by using 16S rRNA gene analysis. Phylogenetic analysis showed that bacterial strains belonging to Bacillus, Halobacillus, and Kocuria were dominant in the rhizosphere of halophytes (Salsola and Atriplex), and Halobacillus and Halomonas were dominating genera from non-rhizospheric and lake-bank soils. Mostly identified strains were moderately halophilic bacteria with optimum growth at 1.5-3.0 M salt concentrations. Most of the bacterial exhibited lipase, protease, cellulase, amylase, gelatinase, and catalase activities. Halophilic and halotolerant Bacilli (AT2RP4, HL1RS13, NRS4HaP9, and LK3HaP7) identified in this study showed optimum lipase, protease, cellulase, and amylase activities at 1.0-1.5 M NaCl concentration, pH 7-8, and temperature 37 °C. These results indicated that halophilic and halotolerant bacteria can be used for bioconversion of organic compounds to useful products under extreme conditions.
Topics: Atriplex; Bacteria; Bacterial Proteins; Biodiversity; Cellulases; Hydrolases; Lakes; Lipase; Peptide Hydrolases; Phylogeny; Rhizosphere; Sodium Chloride; Soil Microbiology
PubMed: 30623303
DOI: 10.1007/s42770-019-00044-y -
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 -
Frontiers in Microbiology 2018Arginine-aspartate-aspartate (RDD) family, representing a category of transmembrane proteins containing one highly conserved arginine and two highly conserved...
Arginine-aspartate-aspartate (RDD) family, representing a category of transmembrane proteins containing one highly conserved arginine and two highly conserved aspartates, has been functionally uncharacterized as yet. Here we present the characterization of a member of this family designated RDD from the moderate halophile NEAU-ST10-40 and report for the first time that RDD should function as a novel Na(Li, K)/H antiporter. It's more interesting whether the highly conserved arginine/aspartate residues among the whole family or between RDD and its selected homologs are related to the protein function. Therefore, we analyzed their roles in the cation-transporting activity through site-directed mutagenesis and found that D154, R124, R129, and D158 are indispensable for Na(Li, K)/H antiport activity whereas neither R35 nor D42 is involved in Na(Li, K)/H antiport activity. As a dual representative of Na(Li, K)/H antiporters and RDD family proteins, the characterization of RDD and the analysis of its important residues will positively contribute to the knowledge of the cation-transporting mechanisms of this novel antiporter and the roles of highly conserved arginine/aspartate residues in the functions of RDD family proteins.
PubMed: 29922240
DOI: 10.3389/fmicb.2018.00807 -
Journal of Environmental Health Science... Dec 2020In this study, the culturable halophilic and halotolerant bacterial diversity was determined in Aran-Bidgol as a thalassohaline seasonal hypersaline lake in Iran.
PURPOSE
In this study, the culturable halophilic and halotolerant bacterial diversity was determined in Aran-Bidgol as a thalassohaline seasonal hypersaline lake in Iran.
METHODS
Thirty water, soil, sediments, coastal mud, multi-color brines and salt crystals samples were extracted and cultured using different media and incubation conditions. Totally 958 isolates were obtained and 87 isolates were selected for further studies, based on morphological, physiological and biochemical tests, representing different morphotypes.
RESULTS
Based on 16S rRNA gene sequence analyses, the isolates exhibited 94.6-100% sequence similarity to the closest known species of the genera , , , , , , , , , , , , , , , , , , , , , , , , , , and and also, comparison of ARDRA patterns among the sequenced strains, using I, UI and II enzymes showed that these patterns are in accordance with the phylogenetic position of these strains.
CONCLUSION
The PCR-RFLP analyses suggested that ARDRA possess a functional potential for distinguishing halophilic bacteria to be used for further studies in elementary steps of isolation to reduce the tedious duplication of isolates.
PubMed: 33312616
DOI: 10.1007/s40201-020-00519-3