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Extremophiles: Life Under Extreme Conditions

Amanda G Bendia, Gabriel G Araujo, André A Pulschen, Bruna Contro, Rubens T D Duarte, Fábio Rodrigues, Douglas Galante, Vivian H Pellizari
Polar volcanoes harbor unique conditions of extreme temperature gradients capable of selecting different types of extremophiles. Deception Island is a marine stratovolcano located at Maritime Antarctica that is notable for its pronounced temperature gradients over very short distances, reaching values up to 100 °C in the fumaroles, and subzero temperatures next to the glaciers. Due to these characteristics, Deception can be considered an interesting analogue of extraterrestrial environments. Our main goal in this study was to isolate thermophilic and psychrophilic bacteria from sediments associated with fumaroles and glaciers from two geothermal sites in Deception Island, comprising temperatures between 0 and 98 °C, and to evaluate their survivability to desiccation and UV-C radiation...
August 14, 2018: Extremophiles: Life Under Extreme Conditions
Francisco Guzmán-Rodríguez, Sergio Alatorre-Santamaría, Lorena Gómez-Ruiz, Gabriela Rodríguez-Serrano, Mariano García-Garibay, Alma Cruz-Guerrero
The influence of CaCl2 and NaCl in the hydrolytic activity and the influence of CaCl2 in the synthesis of fucosylated oligosaccharides using α-L-fucosidase from Thermotoga maritima were evaluated. The hydrolytic activity of α-L-fucosidase from Thermotoga maritima displayed a maximum increase of 67% in the presence of 0.8 M NaCl with water activity (aw ) of 0.9672 and of 138% in the presence of 1.1 M CaCl2 (aw 0.9581). In addition, the hydrolytic activity was higher when using CaCl2 compared to NaCl at aw of 0...
August 7, 2018: Extremophiles: Life Under Extreme Conditions
Tatiana E Petrova, Konstantin M Boyko, Alena Yu Nikolaeva, Tatiana N Stekhanova, Eugeny V Gruzdev, Andrey V Mardanov, Viktor S Stroilov, Jennifer A Littlechild, Vladimir O Popov, Ekaterina Yu Bezsudnova
A novel type 1 geranylgeranyl pyrophosphate synthase GACE1337 has been identified within the genome of a newly identified hyperthermophilic archaeon Geoglobus acetivorans. The enzyme has been cloned and over-expressed in Escherichia coli. The recombinant enzyme has been biochemically and structurally characterized. It is able to catalyze the synthesis of geranylgeranyl pyrophosphate as a major product and of farnesyl pyrophosphate in smaller amounts, as measured by gas chromatography-mass spectrometry at an elevated temperature of 60 °C...
July 30, 2018: Extremophiles: Life Under Extreme Conditions
F Bassani, A Romagnoli, T Cacciamani, A Amici, D Benelli, P Londei, B Märtens, U Bläsi, A La Teana
Eukaryotic eIF5A and its bacterial orthologue EF-P are translation elongation factors whose task is to rescue ribosomes from stalling during the synthesis of proteins bearing particular sequences such as polyproline stretches. Both proteins are characterized by unique post-translational modifications, hypusination and lysinylation, respectively, which are essential for their function. An orthologue is present in all Archaea but its function is poorly understood. Here, we show that aIF5A of the crenarchaeum Sulfolobus solfataricus is hypusinated and forms a stable complex with deoxyhypusine synthase, the first enzyme of the hypusination pathway...
July 25, 2018: Extremophiles: Life Under Extreme Conditions
Wai Kit Chan, Dirk Wildeboer, Hemda Garelick, Diane Purchase
An arsenic-resistant fungal strain, designated WKC-1, was isolated from a waste roaster pile in a historical tin mine in Cornwall, UK and successfully identified to be Acidomyces acidophilus using matrix-assisted laser desorption/ionization time-of-flight/time-of-flight tandem mass spectrometry (MALDI-TOF/TOF MS) proteomic-based biotyping approach. WKC-1 showed considerable resistance to As5+ and Sb5+ where the minimal inhibitory concentration (MIC) were 22500 and 100 mg L-1 , respectively, on Czapex-Dox Agar (CDA) medium; it was substantially more resistant to As5+ than the reference strains CBS 335...
July 23, 2018: Extremophiles: Life Under Extreme Conditions
Noopur Singh, Bijan Choudhury
Hypersaline environment is inhabited by array of microbes which have the potential to produce industrially important products. This study explored biomass and lipid production potential of the halophilic bacterium, strain NS12IITR which was isolated from Sambhar Lake, Rajasthan. Sequencing and phylogenetic analysis revealed that the bacterium belonged to genus Lentibacillus. The salient feature of the isolate is its ability to accumulate total cellular lipid up to 18.9 ± 0.45% of dry cell weight. In addition, trans-esterification of extracted lipid yielded 77...
July 21, 2018: Extremophiles: Life Under Extreme Conditions
Wasim Sajjad, Guodong Zheng, Gaosen Zhang, Xiangxian Ma, Wang Xu, Suliman Khan
Indigenous iron-oxidizing bacteria were isolated on modified selective 9KFe2+ medium from Baiyin copper mine stope, China. Three distinct acidophilic bacteria were isolated and identified by analyzing the sequences of 16S rRNA gene. Based on published sequences of 16S rRNA gene in the GenBank, a phylogenetic tree was constructed. The sequence of isolate WG101 showed 99% homology with Acidithiobacillus ferrooxidans strain AS2. Isolate WG102 exhibited 98% similarity with Leptospirillum ferriphilum strain YSK...
July 19, 2018: Extremophiles: Life Under Extreme Conditions
Karel Kopejtka, Jürgen Tomasch, Boyke Bunk, Cathrin Spröer, Irene Wagner-Döbler, Michal Koblížek
Soda lakes, with their high salinity and high pH, pose a very challenging environment for life. Microorganisms living in these harsh conditions have had to adapt their physiology and gene inventory. Therefore, we analyzed the complete genome of the haloalkaliphilic photoheterotrophic bacterium Rhodobaca barguzinensis strain alga05. It consists of a 3,899,419 bp circular chromosome with 3624 predicted coding sequences. In contrast to most of Rhodobacterales, this strain lacks any extrachromosomal elements. To identify the genes responsible for adaptation to high pH, we compared the gene inventory in the alga05 genome with genomes of 17 reference strains belonging to order Rhodobacterales...
July 18, 2018: Extremophiles: Life Under Extreme Conditions
Patricia S Kumagai, Raissa F Gutierrez, Jose L S Lopes, Julia M Martins, David M Jameson, Aline M Castro, Luiz F Martins, Ricardo DeMarco, Nelma R S Bossolan, B A Wallace, Ana P U Araujo
The biotechnological and industrial uses of thermostable and organic solvent-tolerant enzymes are extensive and the investigation of such enzymes from microbiota present in oil reservoirs is a promising approach. Searching sequence databases for esterases from such microbiota, we have identified in silico a potentially secreted esterase from Acetomicrobium hydrogeniformans, named AhEst. The recombinant enzyme was produced in E. coli to be used in biochemical and biophysical characterization studies. AhEst presented hydrolytic activity on short-acyl-chain p-nitrophenyl ester substrates...
July 16, 2018: Extremophiles: Life Under Extreme Conditions
Manel Ben Abdallah, Fatma Karray, Najwa Kallel, Fabrice Armougom, Najla Mhiri, Marianne Quéméneur, Jean-Luc Cayol, Gaël Erauso, Sami Sayadi
Chott El Jerid is the largest hypersaline ephemeral lake in southern Tunisian Sahara desert and is one of the biggest depressions at the North of Africa. This study aimed to investigate the diversity and abundance of microbial communities inhabiting Chott El Jerid during wet season (when it was flooded), using molecular methods [Illumina Miseq sequencing, DGGE and qPCR (qPCR)]. 16S rRNA gene analyses revealed that bacterial community was dominated by Proteobacteria (especially Ralstonia species), followed by Firmicutes, Bacteroidetes, Cyanobacteria, Actinobacteria and Verrucomicrobia...
July 16, 2018: Extremophiles: Life Under Extreme Conditions
Shaohua Dou, Naiyu Chi, Xinshang Zhou, Qingfang Zhang, Fei Pang, Zhilong Xiu
A novel gene (ANK58566) encoding a cold-active α-amylase was cloned from marine bacterium Bacillus sp. dsh19-1 (CCTCC AB 2015426), and the protein was expressed in Escherichia coli. The gene had a length of 1302 bp and encoded an α-amylase of 433 amino acids with an estimated molecular mass of 50.1 kDa. The recombinant α-amylase (AmyD-1) showed maximum activity at 20 °C and pH 6.0, and retained about 35.7% of activity at 4 °C. The AmyD-1 activity was stimulated by Ca2+ and Na+ . However, the chelating agent, EDTA, inactivated the enzyme...
June 23, 2018: Extremophiles: Life Under Extreme Conditions
G B Slobodkina, R V Baslerov, N K Kostryukova, E A Bonch-Osmolovskaya, A I Slobodkin
A novel moderately thermophilic, anaerobic bacterium, strain STR9T was isolated from terrestrial hot spring at Uzon Caldera, Kamchatka peninsula, Russia. Cells of strain STR9T were spore-forming motile straight or slightly curved rods 0.3 μm in diameter and 1.0-2.0 μm in length having a Gram-positive cell-wall structure. The temperature range for growth was 30-58 °C, with an optimum at 50 °C. The pH range for growth was 5.0-10.5, with an optimum at pH 8.0-9.0. NaCl inhibited growth of the strain STR9T and no growth was evident above 0...
June 18, 2018: Extremophiles: Life Under Extreme Conditions
Lynda Beladjal, Tom Gheysens, James S Clegg, Mohamed Amar, Johan Mertens
We found that spores of Bacillus amyloliquefaciens rank amongst the most resistant to high temperatures with a maximum dry heat tolerance determined at 420 °C. We found that this extreme heat resistance was also maintained after several generations suggesting that the DNA was able to replicate after exposure to these temperatures. Nonetheless, amplifying the bacterial DNA using BOXA1R and (GTG)5 primers was unsuccessful immediately after extreme heating, but was successful after incubation of the heated then cooled spores...
June 5, 2018: Extremophiles: Life Under Extreme Conditions
Amanda M Williams-Rhaesa, Nanaakua K Awuku, Gina L Lipscomb, Farris L Poole, Gabriel M Rubinstein, Jonathan M Conway, Robert M Kelly, Michael W W Adams
Regulated control of both homologous and heterologous gene expression is essential for precise genetic manipulation and metabolic engineering of target microorganisms. However, there are often no options available for inducible promoters when working with non-model microorganisms. These include extremely thermophilic, cellulolytic bacteria that are of interest for renewable lignocellulosic conversion to biofuels and chemicals. In fact, improvements to the genetic systems in these organisms often cease once transformation is achieved...
July 2018: Extremophiles: Life Under Extreme Conditions
Lucy C Stewart, Valerie K Stucker, Matthew B Stott, Cornel E J de Ronde
Raoul Island is a subaerial island volcano approximately 1000 km northeast of New Zealand. Its caldera contains a circumneutral closed-basin volcanic lake and several associated pools, as well as intertidal coastal hot springs, all fed by a hydrothermal system sourced from both meteoric water and seawater. Here, we report on the geochemistry, prokaryotic community diversity, and cultivatable abundance of thermophilic microorganisms of four terrestrial features and one coastal feature on Raoul. Hydrothermal fluid contributions to the volcanic lake and pools make them brackish, and consequently support unusual microbial communities dominated by Planctomycetes, Chloroflexi, Alphaproteobacteria, and Thaumarchaeota, as well as up to 3% of the rare sister phylum to Cyanobacteria, Candidatus Melainabacteria...
July 2018: Extremophiles: Life Under Extreme Conditions
Shuang Zhang, Lei Yan, Weijia Xing, Peng Chen, Yu Zhang, Weidong Wang
The widely distributed Acidithiobacillus ferrooxidans (A. ferrooxidans) lives in extremely acidic conditions by fixing CO2 and nitrogen, and by obtaining energy from Fe2+ oxidation with either downhill or uphill electron transfer pathway and from reduced sulfur oxidation. A. ferrooxidans exists as different genomovars and its genome size is 2.89-4.18 Mb. The chemotactic movement of A. ferrooxidans is regulated by quorum sensing. A. ferrooxidans shows weak magnetotaxis due to formation of 15-70 nm magnetite magnetosomes with surface functional groups...
July 2018: Extremophiles: Life Under Extreme Conditions
Dinka Mandakovic, Jonathan Maldonado, Rodrigo Pulgar, Pablo Cabrera, Alexis Gaete, Viviana Urtuvia, Michael Seeger, Verónica Cambiazo, Mauricio González
As a consequence of the severe climatic change affecting our entire world, many lakes in the Andes Cordillera are likely to disappear within a few decades. One of these lakes is Lejía Lake, located in the central Atacama Desert. The objectives of this study were: (1) to characterize the bacterial community from Lejía Lake shore soil (LLS) using 16S rRNA sequencing and (2) to test a culture-based approach using a soil extract medium (SEM) to recover soil bacteria. This extreme ecosystem was dominated by three phyla: Bacteroidetes, Proteobacteria, and Firmicutes with 29...
July 2018: Extremophiles: Life Under Extreme Conditions
Zhengqun Li, Xue Pei, Ziyu Zhang, Yi Wei, Yanyue Song, Lina Chen, Shouan Liu, Shi-Hong Zhang
In a halotolerant fungus Aspergillus glaucus CCHA, several functional proteins with stress-tolerant activity have been studied, but no secretory enzymes have been identified yet. The unique GH5 cellulase candidate from A. glaucus, an endoglucanase termed as AgCMCase, was cloned, expressed in the Pichia pastoris system and the purified enzyme was characterized. A large amount of recombinant enzyme secreted by the P. pastoris GS115 strain was purified to homogeneity. The molecular weight of the purified endoglucanase is about 55...
July 2018: Extremophiles: Life Under Extreme Conditions
Zorigto Namsaraev, Olga Samylina, Marina Sukhacheva, Gennadii Borisenko, Dimitry Y Sorokin, Tatiana Tourova
Bitter-1 is a shallow hypersaline soda lake in Kulunda Steppe (Altai region, Russia). During a study period between 2005 and 2016, the salinity in the littoral area of the lake fluctuated within the range from 85 to 400 g/L (in July of each year). Light-dependent nitrogen fixation occurred in this lake up to the salt-saturating conditions. The rates increased with a decrease in salinity, both under environmental conditions and in laboratory simulations. The salinities below 100 g/L were favorable for light-dependent nitrogen fixation, while the process was dramatically inhibited above 200 g/L salts...
July 2018: Extremophiles: Life Under Extreme Conditions
Schalk J du Plooy, Akash Anandraj, Sarah White, Renzo Perissinotto, Derek R du Preez
Worldwide, cyanobacterial blooms are becoming more frequent, exacerbated by eutrophication, anthropogenic effects, and global climate change. Environmental factors play a direct role in photosynthesis of cyanobacteria and subsequent cellular changes, growth, and bloom dynamics. This study investigated the photosynthetic functioning of a persistent bloom-forming (18 months) cyanobacterium, Cyanothece sp., isolated from Lake St Lucia, South Africa. DUAL-PAM fluorometric methods were used to observe physiological responses in Cyanothece sp...
July 2018: Extremophiles: Life Under Extreme Conditions
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