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Tomotsumi Fujisawa, Masahiro Abe, Jun Tamogami, Takashi Kikukawa, Naoki Kamo, Masashi Unno
Proteorhodopsin (PR) is a microbial rhodopsin functioning as a light-driven proton pump in aquatic bacteria. We performed low-temperature Raman measurements of PR to obtain the structure of the primary photoproduct, the K intermediate (PRK ). PRK showed the hydrogen-out-of-plane modes that are much less intense than those of bacteriorhodopsin as the prototypical light-driven proton pump from haloarchaea. The present results reveal the significantly relaxed chromophore structure in PRK , which can be coupled to the slow kinetics of the K intermediate...
August 11, 2018: FEBS Letters
Bernhard Tschitschko, Susanne Erdmann, Matthew Z DeMaere, Simon Roux, Pratibha Panwar, Michelle A Allen, Timothy J Williams, Sarah Brazendale, Alyce M Hancock, Emiley A Eloe-Fadrosh, Ricardo Cavicchioli
BACKGROUND: The genomes of halophilic archaea (haloarchaea) often comprise multiple replicons. Genomic variation in haloarchaea has been linked to viral infection pressure and, in the case of Antarctic communities, can be caused by intergenera gene exchange. To expand understanding of genome variation and biogeography of Antarctic haloarchaea, here we assessed genomic variation between two strains of Halorubrum lacusprofundi that were isolated from Antarctic hypersaline lakes from different regions (Vestfold Hills and Rauer Islands)...
June 20, 2018: Microbiome
Micaela Cerletti, María Ines Giménez, Christian Tröetschel, Celeste D' Alessandro, Ansgar Poetsch, Rosana Ester De Castro, Roberto A Paggi
The dynamic changes that take place along the phases of microbial growth (lag, exponential, stationary, and death) have been widely studied in bacteria at the molecular and cellular levels, but little is known for archaea. In this study, a high-throughput approach was used to analyze and compare the proteomes of two haloarchaea during exponential and stationary growth: the neutrophilic Haloferax volcanii and the alkaliphilic Natrialba magadii. Almost 2000 proteins were identified in each species (≈50% of the predicted proteome)...
June 10, 2018: Proteomics
Raphaël Méheust, Andrew K Watson, François-Joseph Lapointe, R Thane Papke, Philippe Lopez, Eric Bapteste
BACKGROUND: Haloarchaea, a major group of archaea, are able to metabolize sugars and to live in oxygenated salty environments. Their physiology and lifestyle strongly contrast with that of their archaeal ancestors. Amino acid optimizations, which lowered the isoelectric point of haloarchaeal proteins, and abundant lateral gene transfers from bacteria have been invoked to explain this deep evolutionary transition. We use network analyses to show that the evolution of novel genes exclusive to Haloarchaea also contributed to the evolution of this group...
June 7, 2018: Genome Biology
Qiong Xue, Xiao-Bin Liu, Yeh-Hsing Lao, Lin-Ping Wu, Dong Wang, Zhen-Qiang Zuo, Jun-Yu Chen, Jing Hou, Yuan-Yuan Bei, Xue-Fei Wu, Kam W Leong, Hua Xiang, Jing Han
Implants decorated with antimicrobial peptides (AMPs) can prevent infection and reduce the risk of creating antibiotic resistance. Yet the restricted mobility of surficial AMP often compromises its activity. Here, we report a simple but effective strategy to allow a more flexible display of AMP on the biomaterial surface and demonstrate its efficacy for wound healing. The AMP, tachyplesin I (Tac), is tagged with the polyhydroxyalkanoate-granule-associated protein (PhaP) and immobilized on haloarchaea-produced poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBHV) via hydrophobic interaction...
September 2018: Biomaterials
Siham Akmoussi-Toumi, Souad Khemili-Talbi, Imen Ferioune, Salima Kebbouche-Gana
The present study investigates the purification and biochemical characterization of an extracellular lipase (HML) from Haloarchaea Haloferax mediterranei strain ATS1, isolated from the Sebkha (Medea, Algeria). The pure protein was obtained with ammonium sulfate precipitation (40-70%)-dialysis and UNO Q-6 FPLC, and characterized biochemically. Matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF/MS) analysis revealed that the purified enzyme was a monomer, with a molecular mass of 45,011...
September 2018: International Journal of Biological Macromolecules
Yeon Bee Kim, Joon Yong Kim, Hye Seon Song, Changsu Lee, Seung Woo Ahn, Se Hee Lee, Min Young Jung, Jin-Kyu Rhee, Juseok Kim, Dong-Wook Hyun, Jin-Woo Bae, Seong Woon Roh
Environmental temperature is one of the most important factors for the growth and survival of microorganisms. Here we describe a novel extremely halophilic archaeon (haloarchaea) designated as strain CBA1119T isolated from solar salt. Strain CBA1119T had the highest maximum and optimal growth temperatures (66 °C and 55 °C, respectively) and one of the largest genome sizes among haloarchaea (5.1 Mb). It also had the largest number of strain-specific pan-genome orthologous groups and unique pathways among members of the genus Natrinema in the class Halobacteria...
May 17, 2018: Scientific Reports
Jan Jehlička, Adam Culka, Lilly Mana, Aharon Oren
Cell suspensions of the haloarchaea Halorubrum sodomense and Halobacterium salinarum and the extremely halophilic bacterium Salinibacter ruber (Bacteroidetes) in saturated solutions of chlorides and sulfates (NaCl, KCl, MgSO4 ·7H2 O, K2 SO4 , and (NH4 )Al(SO4 )2 ·12H2 O) were left to evaporate to produce micrometric inclusions in laboratory-grown crystals. Raman spectra of these pinkish inclusions were obtained using a handheld Raman spectrometer with green excitation (532 nm). This portable instrument does not include any microscopic tool...
July 2018: Analytical and Bioanalytical Chemistry
Jessica J Evans, Patrick E Gygli, Julienne McCaskill, Linda C DeVeaux
The haloarchaea are unusual in possessing genes for multiple homologs to the ubiquitous single-stranded DNA binding protein (SSB or replication protein A, RPA) found in all three domains of life. Halobacterium salinarum contains five homologs: two are eukaryotic in organization, two are prokaryotic and are encoded on the minichromosomes, and one is uniquely euryarchaeal. Radiation-resistant mutants previously isolated show upregulation of one of the eukaryotic-type RPA genes. Here, we have created deletions in the five RPA operons...
April 20, 2018: Genes
Masoomeh Selseleh Hassan Kiadehi, Mohammad Ali Amoozegar, Sedigheh Asad, Maryam Siroosi
Azo dyes are being extensively used in textile industries, so finding a proper solution to decolorize them is of high importance. In order to find azo dye decolorizing strains among haloarchaea, which are well known for their tolerance to harsh environmental conditions, fifteen haloarchaeal strains were screened. Halogeometricum sp. strain A and Haloferax sp. strain B with the highest decolorization ability (95% and 91% for Remazol black B; both about 60% for Acid blue 161, respectively) were selected for further studies...
March 2018: Water Science and Technology: a Journal of the International Association on Water Pollution Research
Yu Nakajima, Takashi Tsukamoto, Yohei Kumagai, Yoshitoshi Ogura, Tetsuya Hayashi, Jaeho Song, Takashi Kikukawa, Makoto Demura, Kazuhiro Kogure, Yuki Sudo, Susumu Yoshizawa
Light-driven ion-pumping rhodopsins are widely distributed among bacteria, archaea, and eukaryotes in the euphotic zone of the aquatic environment. H+ -pumping rhodopsin (proteorhodopsin: PR), Na+ -pumping rhodopsin (NaR), and Cl- -pumping rhodopsin (ClR) have been found in marine bacteria, which suggests that these genes evolved independently in the ocean. Putative microbial rhodopsin genes were identified in the genome sequences of marine Cytophagia. In the present study, one of these genes was heterologously expressed in Escherichia coli cells and the rhodopsin protein named Rubricoccus marinus halorhodopsin (RmHR) was identified as a light-driven inward Cl- pump...
March 29, 2018: Microbes and Environments
Omar Federico Ordoñez, María Cecilia Rasuk, Mariana Noelia Soria, Manuel Contreras, María Eugenia Farías
Biofilms, microbial mats, and microbialites dwell under highly limiting conditions (high salinity, extreme aridity, pH, and elevated arsenic concentration) in the Andean Puna. Only recent pioneering studies have described the microbial diversity of different Altiplano lakes and revealed their unexpectedly diverse microbial communities. Arsenic metabolism is proposed to be an ancient mechanism to obtain energy by microorganisms. Members of Bacteria and Archaea are able to exploit arsenic as a bioenergetic substrate in either anaerobic arsenate respiration or chemolithotrophic growth on arsenite...
March 8, 2018: Microbial Ecology
Blanca Vera-Gargallo, Antonio Ventosa
Hypersaline environments encompass aquatic and terrestrial habitats. While only a limited number of studies on the microbial diversity of saline soils have been carried out, hypersaline lakes and marine salterns have been thoroughly investigated, resulting in an aquatic-biased knowledge about life in hypersaline environments. To improve our understanding of the assemblage of microbes thriving in saline soils, we assessed the phylogenetic diversity and metabolic potential of the prokaryotic community of two hypersaline soils (with electrical conductivities of ~24 and 55 dS/m) from the Odiel saltmarshes (Spain) by metagenomics...
March 8, 2018: Genes
Diego Rivera Gelsinger, Jocelyne DiRuggiero
Haloarchaea in their natural environment are exposed to hypersalinity, intense solar radiation, and desiccation, all of which generate high levels of oxidative stress. Previous work has shown that haloarchaea are an order of magnitude more resistant to oxidative stress than most mesophilic organisms. Despite this resistance, the pathways haloarchaea use to respond to oxidative stress damage are similar to those of nonresistant organisms, suggesting that regulatory processes might be key to their robustness...
May 1, 2018: Journal of Bacteriology
Taha Menasria, Margarita Aguilera, Hacene Hocine, Leyla Benammar, Ammar Ayachi, Abdelkrim Si Bachir, Ahmed Dekak, Mercedes Monteoliva-Sánchez
The diversity of haloarchaea associated with different dry salt lakes in northeastern Algeria was investigated together with their potential of hydrolytic enzyme production. A total of 68 aerobic halophilic archaea were isolated from saline sediments. Based on the 16S rRNA gene sequencing, the isolates were assigned to seven phylotypes within the class Halobacteria, namely Haloarcula, Halococcus, Haloferax, Halogeometricum, Haloterrigena, Natrialba, and Natrinema. The results showed that Haloferax group was found to be dominant in all samples (30 isolates) (44%) with high diversity, followed by Halococcus spp...
March 2018: Microbiological Research
Swati Almeida-Dalmet, Carol D Litchfield, Patrick Gillevet, Bonnie K Baxter
Haloarchaea that inhabit Great Salt Lake (GSL), a thalassohaline terminal lake, must respond to the fluctuating climate conditions of the elevated desert of Utah. We investigated how shifting environmental factors, specifically salinity and temperature, affected gene expression in the GSL haloarchaea, NA6-27, which we isolated from the hypersaline north arm of the lake. Combined data from cultivation, microscopy, lipid analysis, antibiotic sensitivity, and 16S rRNA gene alignment, suggest that NA6-27 is a member of the Haloarcula genus...
January 22, 2018: Genes
Jiao Wang, Yingchun Liu, Ying Liu, Kaixin Du, Shuqi Xu, Yuchen Wang, Mart Krupovic, Xiangdong Chen
Genomes of halophilic archaea typically contain multiple loci of integrated mobile genetic elements (MGEs). Despite the abundance of these elements, however, mechanisms underlying their site-specific integration and excision have not been investigated. Here, we identified and characterized a novel recombination system encoded by the temperate pleolipovirus SNJ2, which infects haloarchaeon Natrinema sp. J7-1. SNJ2 genome is inserted into the tRNAMet gene and flanked by 14 bp direct repeats corresponding to attachment core sites...
March 16, 2018: Nucleic Acids Research
Xiao-Bin Liu, Lin-Ping Wu, Jing Hou, Jun-Yu Chen, Jing Han, Hua Xiang
The published online version contains mistake in the funding information. Instead of 30370096, it should have been 31370096.
February 2018: Applied Microbiology and Biotechnology
Souhila Mazguene, Mosè Rossi, Marta Gogliettino, Gianna Palmieri, Ennio Cocca, Sara Mirino, Nacera Imadalou-Idres, Said Benallaoua
Halophilic archaea, thriving in hypersaline environments, synthesize antimicrobial substances with an unknown role, called halocins. It has been suggested that halocin production gives transient competitive advantages to the producer strains and represents one of the environmental factors influencing the microbial community composition. Herein, we report on the antibacterial activity of a new haloarchaeon selected from solar salterns of the northern coast of Algeria. A total of 81 halophilic strains, isolated from the microbial consortia, were screened for the production of antimicrobial compounds by interspecies competition test and against a collection of commercial haloarchaea...
March 2018: Extremophiles: Life Under Extreme Conditions
Javier Torregrosa-Crespo, Linda Bergaust, Carmen Pire, Rosa María Martínez-Espinosa
Haloarchaea thrive under saline and hypersaline conditions and often dominate microbial communities in saltmarshes, salted lakes/soils, and some oceanic areas. Some of the predominant species show denitrifying capabilities, although it remains unclear whether they are complete or partial denitrifiers. As complete denitrifiers, they could play important roles buffering ecosystems in which nitrate and nitrite appear as contaminants. However, partial denitrifying haloarchaea could contribute to the emission of nitrogenous gasses, thus acting as drivers of climate change and ozone depletion...
December 9, 2017: FEMS Microbiology Letters
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