Halophiles – Taxonomy, Diversity, Physiology and Applications

Kanekar, Pradnya Pralhad; Kanekar, Sagar Pralhad; Dhakephalkar, Prashant K.

doi:10.1007/978-94-007-2229-3_1

Cited by 25 publications

(16 citation statements)

References 159 publications

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“…In contrast, moderate halophiles, which grow at 5-20% NaCl (Kanekar et al, 2012), keep their intracellular ionic concentrations at low levels and use organic solutes to produce the necessary osmotic balance without dramatically altering the structure of their proteome (Oren, 2011). By comparing the distribution of genes based on the isoelectric point (pI) of the encoded proteins (Figure 4), we found that for all Nitrosopumilus species, the median pI of the overall proteome or only those of predicted proteins with no integral membrane domains were similar to each other (B6.5) but significantly higher (KruskalWallis test, Po0.001) than in exemplary moderate halophiles (B5.7).…”

Section: T R a N S P E P T Id A S E ( G G T ) M E T H Y Lp H O S P H mentioning

confidence: 99%

Comparative genomics reveals adaptations of a halotolerant thaumarchaeon in the interfaces of brine pools in the Red Sea

et al. 2014

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The bottom of the Red Sea harbors over 25 deep hypersaline anoxic basins that are geochemically distinct and characterized by vertical gradients of extreme physicochemical conditions. Because of strong changes in density, particulate and microbial debris get entrapped in the brine-seawater interface (BSI), resulting in increased dissolved organic carbon, reduced dissolved oxygen toward the brines and enhanced microbial activities in the BSI. These features coupled with the deep-sea prevalence of ammonia-oxidizing archaea (AOA) in the global ocean make the BSI a suitable environment for studying the osmotic adaptations and ecology of these important players in the marine nitrogen cycle. Using phylogenomic-based approaches, we show that the local archaeal community of five different BSI habitats (with up to 18.2% salinity) is composed mostly of a single, highly abundant Nitrosopumilus-like phylotype that is phylogenetically distinct from the bathypelagic thaumarchaea; ammonia-oxidizing bacteria were absent. The composite genome of this novel Nitrosopumilus-like subpopulation (RSA3) co-assembled from multiple single-cell amplified genomes (SAGs) from one such BSI habitat further revealed that it shares B54% of its predicted genomic inventory with sequenced Nitrosopumilus species. RSA3 also carries several, albeit variable gene sets that further illuminate the phylogenetic diversity and metabolic plasticity of this genus. Specifically, it encodes for a putative proline-glutamate 'switch' with a potential role in osmotolerance and indirect impact on carbon and energy flows. Metagenomic fragment recruitment analyses against the composite RSA3 genome, Nitrosopumilus maritimus, and SAGs of mesopelagic thaumarchaea also reiterate the divergence of the BSI genotypes from other AOA.

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Section: T R a N S P E P T Id A S E ( G G T ) M E T H Y Lp H O S P H mentioning

confidence: 99%

Comparative genomics reveals adaptations of a halotolerant thaumarchaeon in the interfaces of brine pools in the Red Sea

et al. 2014

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“…All isolated had the opportunity to growth at 0.85M (5%) of NaCl with a maximum development. Our results showed that isolated bacterial could get in the classification as some halophilic bacteria (2% to 5% NaCl), moderately halophilic (5% to 20% NaCl), and extreme halophilic (20% to 30% NaCl), depending on their salt requirement according to Oren (2008), Kanekar et al (2011) andFaraj et al (2016).…”

Section: Strains Isolated From Sierra Viesca Rancho Penjamo Coahuilamentioning

confidence: 68%

Plant growth-promoting rhizobacteria associated to candelilla rhizosphere (Euphorbia antisyphilitica) and its effects on Arabidopsis thaliana seedlings

Salazar-Ramírez

Sáenz‐Mata

Rangel

et al. 2021

Not Bot Horti Agrobo

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In the communities of Sierra Mojada and Viesca, Coahuila, Mexico of Coahuila desert, two rhizosphere samplings of candelilla (Euphorbia antisyphilitica Zucc) were collected to isolate, characterize, and identifying plant growth-promoting rhizobacteria (PGPR); 165 rhizobacteria were tested in vitro with Arabidopsis thaliana seedlings to evaluate their potential as plant growth promoters, and obtaining 21 strains with best results in the variables of the number of secondary roots and fresh weight concerning the uninoculated control. Their salinity tolerance was evaluated at concentrations from 0.85 M, 1.7 M and 2.55 M of NaCl. Biochemical tests were accomplishing such as siderophores production, phosphates solubilization, production of Indole-3-acetic acid (IAA), and the activity of the ACC deaminase enzyme. The results obtained from 21 strains selected, high activities were obtained in organic substances like a siderophores since they developed a translucent orange halo around their growth; four rhizobacteria developed a clear halo around the bacterial growth with a thickness between 1.487 mm ± 0.667 mm and 5.267 mm ± 0.704 mm in phosphates solubilization; in the production of Indole-3-acetic acid (IAA), the bacterial strains showed the presence of this phytohormone, with values from 4.444 μg mL-1 to 19.286 μg mL-1; and according to the activity of the ACC deaminase enzyme, values from 0.424 to 1.306 µmol α-KB/h/mg Pr were showed. 16S rRNA sequencing was carried out and genus identified were Bacillus, Staphylococcus, Acinetobacter, Cronobacter and Siccibacter. The results obtained show the potential of the isolated rhizobacteria as growth promoters and the increase in the biomass of the Arabidopsis thaliana seedlings is evident. This is a first indication to proceed to carry out tests in different phenological stages in crops of agricultural importance.

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“…The growth rates of selected strains were estimated as described before. The results in Figure 1 demonstrate that bacteria strain number 4 have a large salinity growth interval (2.5-17.5% w/v), which means that it is a moderately halophilic bacteria; in addition, the archaea strain N has a growth salt interval from 15 to 27% (w/v), suggesting that it is an extreme halophile [16].…”

Section: Morphology and Physiologymentioning

confidence: 97%

“…The 16S rRNA gene analysis related their grouping in seven genera: Virgibacillus, Idiomarina, Halobacillus for bacteria; Halorubrum, Halobacterium, Halogeometricum, and Natrinema for archaea. Bacteria Gram-negative isolates of the Idiomarina genus belonged to the Gammaproteobacteria Class, Idiomarinacaea family and Gram-positive of Virgibacillus and Halobacillus belonged to the Bacilli Class, Bacillaceae family [16,17]. The archaea genera all belonged to the Halobacteria Class, Halorubrum: Halorubraceae family; Natrinema: Natrialbaceae family; Halobacterium: Halobacteriaceae family; Halogeometricum: Haloferacaceae; they all have high salt tolerance and general pigment production [16].…”

Section: Identification By 16s Rrna Gene Analysismentioning

confidence: 99%

Test for the Production and Assay of the Proteolytic Activities of Halophilic Bacteria and Archaea Isolated from Algerian Hypersaline Environments

Benmebarek

Escuder-Rodríguez

González-Siso

et al. 2020

The 1st International Electronic Conference on Microbiology

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: The present work was carried out on 133 halophilic strains isolated on MGM (Modified Growth Medium) medium with 12 and 23% (w/v) of salt. A screening of the extracellular proteolytic activities, carried out on the same medium supplemented with casein or gelatin at 1% (w/v), allowed us to select 24 bacterial and 21 archaeal strains presenting a precipitate around the colonies for casein and/or a translucent halo (after addition of Frazier’s reagent) for gelatin. The enzymatic test was performed on liquid medium in microculture in a 2 mL Eppendorf tube. The assay of the proteolytic activity, using Azocasein as substrate, followed two protocols—the first with PBS and the second with Tris HCl, with positive and negative controls—and demonstrated interesting results for 10 strains among the 45 tested including five bacteria and five archaea. These underwent morphological, physiological and molecular characterizations based on amplification and sequencing of the 16S ribosomal RNA gene.

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Halophiles – Taxonomy, Diversity, Physiology and Applications

Cited by 25 publications

References 159 publications

Comparative genomics reveals adaptations of a halotolerant thaumarchaeon in the interfaces of brine pools in the Red Sea

Comparative genomics reveals adaptations of a halotolerant thaumarchaeon in the interfaces of brine pools in the Red Sea

Plant growth-promoting rhizobacteria associated to candelilla rhizosphere (Euphorbia antisyphilitica) and its effects on Arabidopsis thaliana seedlings

Test for the Production and Assay of the Proteolytic Activities of Halophilic Bacteria and Archaea Isolated from Algerian Hypersaline Environments

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