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Extremophiles: Life Under Extreme Conditions

Santina Soru, Veronica Malavasi, Pierluigi Caboni, Alessandro Concas, Giacomo Cao
The extremophile green alga Coccomyxa melkonianii SCCA 048 was investigated to evaluate its ability to grow in culture media with different pH. Specifically, Coccomyxa melkonianii was sampled in the Rio Irvi river (Sardinia, Italy) which is severely polluted by heavy metals as a result of abandoned mining activities. In this study, the strain was cultivated in growth media where the pH was kept fixed at the values of 4.0, 6.8 and 8.0, respectively. During the investigation, a significant phenotypic plasticity of this strain was observed...
October 19, 2018: Extremophiles: Life Under Extreme Conditions
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October 19, 2018: Extremophiles: Life Under Extreme Conditions
María Antonela Colonnella, Leonardo Lizarraga, Leticia Rossi, Rocío Díaz Peña, Diego Egoburo, Nancy I López, Laura J Raiger Iustman
Environments co-contaminated with heavy metals and hydrocarbons have become an important problem worldwide, especially due to the effect of metals on hydrocarbon degrading microorganisms. Pseudomonas extremaustralis, a bacterium isolated from a pristine pond in Antarctica, showed high capabilities to cope with environmental stress and a very versatile metabolism that includes alkane degradation under microaerobic conditions. In this work, we analyzed P. extremaustralis' capability to resist high copper concentrations and the effect of copper presence in diesel biodegradation...
October 17, 2018: Extremophiles: Life Under Extreme Conditions
Otakar Strunecký, Karel Kopejtka, Franz Goecke, Jürgen Tomasch, Jaromír Lukavský, Amir Neori, Silke Kahl, Dietmar H Pieper, Plamen Pilarski, David Kaftan, Michal Koblížek
Genotypic and morphological diversity of cyanobacteria in the Rupite hot spring (Bulgaria) was investigated by means of optical microscopy, cultivation, single-cell PCR, and 16S rRNA gene amplicon sequencing. Altogether, 34 sites were investigated along the 71-39 °C temperature gradient. Analysis of samples from eight representative sites shown that Illumina, optical microscopy, and Roche 454 identified 72, 45 and 19% respective occurrences of all cumulatively present taxa. Optical microscopy failed to detect species of minor occurrence; whereas, amplicon sequencing technologies suffered from failed primer annealing and the presence of species with extensive extracellular polysaccharides production...
October 4, 2018: Extremophiles: Life Under Extreme Conditions
Sonali Majumdar, Michael P Terns
Diverse CRISPR-Cas immune systems protect archaea and bacteria from viruses and other mobile genetic elements. All CRISPR-Cas systems ultimately function by sequence-specific destruction of invading complementary nucleic acids. However, each CRISPR system uses compositionally distinct crRNP [CRISPR (cr) RNA/Cas protein] immune effector complexes to recognize and destroy invasive nucleic acids by unique molecular mechanisms. Previously, we found that Type I-A (Csa) effector crRNPs from Pyrococcus furiosus function in vivo to eliminate invader DNA...
October 3, 2018: Extremophiles: Life Under Extreme Conditions
Filomena De Leo, Angelina Lo Giudice, Chiara Alaimo, Giusy De Carlo, Alessandro Ciro Rappazzo, Marco Graziano, Emilio De Domenico, Clara Urzì
The occurrence of cultivable fungi was investigated along the water column (25-2500 m depth) of four off-shore stations in the Mediterranean basin. An unexpected high abundance of fungi, accompanied by a scarce biodiversity, was observed up to 2500 m depth. The black yeast Hortaea werneckii, known to be one of the most salt tolerant eukaryotic organisms, was isolated for the first time from the Mediterranean Sea, and it was the dominant fungus present in seawater in almost all stations and depths, suggesting its ubiquitous distribution...
October 1, 2018: Extremophiles: Life Under Extreme Conditions
Juan José Marizcurrena, Wilner Martínez-López, Hongju Ma, Tilman Lamparter, Susana Castro-Sowinski
Photolyases are DNA-repairing flavoproteins that are represented in most phylogenetic taxa with the exception of placental mammals. These enzymes reduce the ultraviolet-induced DNA damage; thus, they have features that make them very attractive for dermatological or other medical uses, such as the prevention of human skin cancer and actinic keratosis. In this work, we identified a 50.8 kDa photolyase from the UVC-resistant Antarctic bacterium Hymenobacter sp. UV11. The enzyme was produced by recombinant DNA technology, purified using immobilized metal affinity chromatography and its activity was analyzed using different approaches: detection of cyclobutane pyrimidine dimers (CPDs) by immunochemistry, high-performance liquid chromatography and comet assays using Chinese Hamster Ovary (CHO) and immortalized nontumorigenic human epidermal (HaCat) cells...
September 28, 2018: Extremophiles: Life Under Extreme Conditions
Muhammad Arif, Naeem Rashid, Sumera Perveen, Qamar Bashir, Muhammad Akhtar
The gene-encoding Indole-3-glycerol phosphate synthase, a key enzyme involved in the cyclization of 1-(o-carboxyphenylamino)-1-deoxyribulose 5-phosphate, from Pyrococcus furiosus was cloned and expressed in Escherichia coli. The gene product was produced in the soluble and active form. The recombinant protein, purified to apparent homogeneity, displayed highest activity at 100 °C and pH of 5.5. The recombinant enzyme followed Michaelis-Menten kinetics exhibiting apparent Vmax and Km values of 20 ± 0...
September 27, 2018: Extremophiles: Life Under Extreme Conditions
Takenori Satomura, Junji Hayashi, Tatsuya Ohshida, Haruhiko Sakuraba, Toshihisa Ohshima, Shin-Ichiro Suye
A gene-encoding a dye-linked D-lactate dehydrogenase (Dye-DLDH) homolog was identified in the genome of the hyperthermophilic archaeon Thermoproteus tenax. The gene was expressed in Escherichia coli and the product was purified to homogeneity. The recombinant protein exhibited highly thermostable Dye-DLDH activity. To date, four types of Dye-DLDH have been identified in hyperthermophilic archaea (in Aeropyrum pernix, Sulfolobus tokodaii, Archaeoglobus fulgidus, and Candidatus Caldiarchaeum subterraneum). The amino acid sequence of T...
September 11, 2018: Extremophiles: Life Under Extreme Conditions
En-Min Zhou, Wen-Dong Xian, Chrisabelle C Mefferd, Scott C Thomas, Arinola L Adegboruwa, Nathan Williams, Senthil K Murugapiran, Jeremy A Dodsworth, Rakesh Ganji, Meng-Meng Li, Yi-Ping Ding, Lan Liu, Tanja Woyke, Wen-Jun Li, Brian P Hedlund
Thermus species are widespread in natural and artificial thermal environments. Two new yellow-pigmented strains, L198T and L423, isolated from Little Hot Creek, a geothermal spring in eastern California, were identified as novel organisms belonging to the genus Thermus. Cells are Gram-negative, rod-shaped, and non-motile. Growth was observed at temperatures from 45 to 75 °C and at salinities of 0-2.0% added NaCl. Both strains grow heterotrophically or chemolithotrophically by oxidation of thiosulfate to sulfate...
November 2018: Extremophiles: Life Under Extreme Conditions
Scott Wushke, Brian Fristensky, Xiang Li Zhang, Vic Spicer, Oleg V Krokhin, David B Levin, Matthew B Stott, Richard Sparling
A metabolic, genomic and proteomic assessment of Fervidobacterium pennivorans strains was undertaken to clarify the metabolic and genetic capabilities of this Thermotogales species. The type strain Ven5 originally isolated from a hot mud spa in Italy, and a newly isolated strain (DYC) from a hot spring at Ngatamariki, New Zealand, were compared for metabolic and genomic differences. The fermentation profiles of both strains on cellobiose generated similar major end products (acetate, alanine, glutamate, H2 , and CO2 )...
November 2018: Extremophiles: Life Under Extreme Conditions
Chunli Zheng, Li Zhang, Minjie Chen, Xue Qiang Zhao, Yizhuo Duan, Ye Meng, Xuefeng Zhang, Ren Fang Shen
The glutathione synthetase system (GSS) is an important pathway of glutathione synthesis and plays a key role in heavy metal resistance. In this work, the response of Acidithiobacillus ferrooxidans to extracellular Cd2+ was investigated, and the interplay between Cd2+ resistance and the expression of GSS related-genes was analyzed by reverse-transcription quantitative PCR (RT-PCR). During growth in the presence of 5, 15 and 30 mM Cd2+ , the transcript levels of eight GSS pathway genes were affected between 0...
November 2018: Extremophiles: Life Under Extreme Conditions
Angela Casillo, Marcello Ziaco, Buko Lindner, Ermenegilda Parrilli, Dominik Schwudke, Aurora Holgado, Rudi Beyaert, Rosa Lanzetta, Maria Luisa Tutino, Maria Michela Corsaro
Psychrobacter arcticus 273-4 is a Gram-negative bacterium isolated from a 20,000-to-30,000-year-old continuously frozen permafrost in the Kolyma region in Siberia. The survival strategies adopted to live at subzero temperatures include all the outer membrane molecules. A strategic involvement in the well-known enhancement of cellular membrane fluidity is attributable to the lipopolysaccharides (LPSs). These molecules covering about the 75% of cellular surface contribute to cold adaptation through structural modifications in their portions...
November 2018: Extremophiles: Life Under Extreme Conditions
Olivier Zablocki, Leonardo van Zyl, Marla Trindade
Bacterial viruses ("phages") play important roles in the regulation and evolution of microbial communities in most ecosystems. Terrestrial hot springs typically contain thermophilic bacterial communities, but the diversity and impacts of its associated viruses ("thermophilic phages") are largely unexplored. Here, we provide a taxonomic overview of phages that have been isolated strictly from terrestrial hot springs around the world. In addition, we placed 17 thermophilic phage genomes in a global phylogenomic context to detect evolutionary patterns...
November 2018: Extremophiles: Life Under Extreme Conditions
José Q García-Maldonado, Alejandra Escobar-Zepeda, Luciana Raggi, Brad M Bebout, Alejandro Sanchez-Flores, Alejandro López-Cortés
Bacterial and archaeal community structure of five microbial communities, developing at different salinities in Baja California Sur, Mexico, were characterized by 16S rRNA sequencing. The response of the microbial community to artificial changes in salinity-sulfate concentrations and to addition of trimethylamine was also evaluated in microcosm experiments. Ordination analyses of the microbial community structure showed that microbial composition was distinctive for each hypersaline site. Members of bacteria were dominated by Bacteroidetes and Proteobacteria phyla, while Halobacteria of the Euryarchaeota phylum was the most represented class of archaea for all the environmental samples...
November 2018: Extremophiles: Life Under Extreme Conditions
Feng Zhao, Sabine Filker
Salinity is an important factor when exploring the limits known for life. Therefore, hypersaline systems have attracted much attention in recent years. In this study, we investigated the protistan diversity and community composition in two natural salt evaporation ponds (27-30% salinity) located in an ancient volcanic crater on the Cape Verde island Sal using high-throughput DNA sequencing. Our study revealed a broad range of protistan taxa and a high taxonomic diversity within the Ciliophora, Dinophyceae, and Chlorophyta...
November 2018: Extremophiles: Life Under Extreme Conditions
Ida Romano, Annalisa De Angelis, Annarita Poli, Pietro Ragni, Laura Lilla, Gianluigi Zito, Barbara Nicolaus, Anna Chiara De Luca, Paola Di Donato
Spores of the genus Bacillus are able to resist ionizing radiations and therefore they are a suitable biological model for studies in Astrobiology, i.e. the multidisciplinary approach to the study of the origin and evolution of life on Earth and in the universe. The resistance to γ-radiation is an important issue in Astrobiology in relation to the search for bacterial species that could adapt to life in space. This study investigates the resistance of spores of the thermophilic bacteria Parageobacillus thermantarcticus to γ-rays...
November 2018: 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...
November 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...
November 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...
November 2018: Extremophiles: Life Under Extreme Conditions
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