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Extremophiles: Life Under Extreme Conditions

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December 4, 2017: Extremophiles: Life Under Extreme Conditions
Francesca Anna Fusco, Raffaele Ronca, Gabriella Fiorentino, Emilia Pedone, Patrizia Contursi, Simonetta Bartolucci, Danila Limauro
Dictyoglomus turgidum is a hyperthermophilic, anaerobic, gram-negative bacterium that shows an array of putative glycoside hydrolases (GHs) encoded by its genome, a feature that makes this microorganism very interesting for biotechnological applications. The aim of this work is the characterization of a hyperthermophilic GH5, Dtur_0671, of D. turgidum, annotated as endoglucanase and herein named DturCelB in agreement to DturCelA, which was previously characterized. The synthetic gene was expressed in Escherichia coli...
November 25, 2017: Extremophiles: Life Under Extreme Conditions
Iram Aziz, Naeem Rashid, Raza Ashraf, Masood Ahmed Siddiqui, Tadayuki Imanaka, Muhammad Akhtar
Genome sequence of the hyperthermophilic archaeon Pyrobaculum calidifontis contains an open reading frame, Pcal_0632, annotated as glyceraldehyde-3-phosphate dehydrogenase, which is partially overlapped with phosphoglycerate kinase. In the phylogenetic tree, Pcal_0632 clustered with phosphorylating glyceraldehyde-3-phosphate dehydrogenases characterized from hyperthermophilic archaea and exhibited highest identity of 54% with glyceraldehyde-3-phosphate dehydrogenase from Sulfolobus tokodaii. To examine biochemical function of the protein, Pcal_0632 gene was expressed in Escherichia coli and the gene product was purified...
November 25, 2017: Extremophiles: Life Under Extreme Conditions
Saher Shahid, Razia Tajwar, Muhammad Waheed Akhtar
A novel, family GH10 enzyme, Xyn10B from Acidothermus cellulolyticus 11B was cloned and expressed in Escherichia coli. This enzyme was purified to homogeneity by binding to regenerated amorphous cellulose. It had higher binding on Avicel as compared to insoluble xylan due to the presence of cellulose-binding domains, CBM3 and CBM2. This enzyme was optimally active at 70 °C and pH 6.0. It was stable up to 70 °C while the CD spectroscopy analysis showed thermal unfolding at 80 °C. Xyn10B was found to be a trifunctional enzyme having endo-xylanase, arabinofuranosidase and acetyl xylan esterase activities...
November 23, 2017: Extremophiles: Life Under Extreme Conditions
Tsubasa Washio, Tadao Oikawa
We successfully expressed the L-aspartate oxidase homolog gene (accession no: OCC_06611) of Thermococcus litoralis DSM 5473 in the soluble fraction of Escherichia coli BL21 (DE3) using a pET21b vector with 6X His tag at its C-terminus. The gene product (Tl-LASPO) showed L-aspartate oxidase activity in the presence of FAD in vitro, and this report is the first that details an L-aspartate oxidase derived from a Thermococcus species. The homologs of Tl-LASPO existed mainly in archaea, especially in the genus of Thermococcus, Pyrococcus, Sulfolobus, and Halobacteria...
November 15, 2017: Extremophiles: Life Under Extreme Conditions
Samaneh Jafari, Seyed-Soheil Aghaei, Hossein Afifi-Sabet, Masoomeh Shams-Ghahfarokhi, Zahra Jahanshiri, Mohammadhassan Gholami-Shabani, Seyedahmad Shafiei-Darabi, Mehdi Razzaghi-Abyaneh
In the present study, halophilic bacteria communities were explored in saline soils of Howze-Soltan playa in Iran with special attention to their biological activity against an aflatoxigenic Aspergillus parasiticus NRRL 2999. Halophilic bacteria were isolated from a total of 20 saline soils using specific culture media and identified by 16S rRNA sequencing in neighbor-joining tree analysis. Antifungal and antiaflatoxigenic activities of the bacteria were screened by a nor-mutant A. parasiticus NRRL 2999 using visual agar plate assay and confirmed by high-performance liquid chromatography...
November 13, 2017: Extremophiles: Life Under Extreme Conditions
Enrique Martínez-Carranza, Gabriel Y Ponce-Soto, Alma L Díaz-Pérez, Erasmo Cadenas, Valeria Souza, Jesús Campos-García
The Cuatro Ciénegas Basin (CCB) within the Chihuahuan Desert in México is an extremely oligotrophic oasis with negligible phosphorous levels, described as a hot spot of biodiversity, not only in stromatolites and microbial mats, but also in living forms in general. The microorganisms possess the capability to produce a wide variety of virulence factors, antibiotics, and quorum-sensing (QS) crosstalk signals such as non-ribosomal cyclodipeptides (CDPs) which enables them to colonize diverse ecological niches...
November 11, 2017: Extremophiles: Life Under Extreme Conditions
Masahito Murakami, Makoto Saito, Hirokazu Yokobori, Katsushi Nishimura, Minoru Tanigawa, Yoko Nagata
Pyrobaculum islandicum is a hyperthermophilic archaeon that grows optimally at 95-100 °C. In the previous study, we extensively purified a serine racemase from this organism and cloned the gene for overexpression in Escherichia coli (Ohnishi et al. 2008). This enzyme also exhibits highly thermostable L-serine/L-threonine dehydratase activity. In the present study, we aimed to elucidate the molecular mechanisms underlying the high thermostability of this enzyme. A recombinant variant of this enzyme, PiSRvt, constructed by truncating the C-terminal 72 amino acids, was compared with the native enzyme, PiSR...
November 9, 2017: Extremophiles: Life Under Extreme Conditions
Jonathan Botha, Eshchar Mizrachi, Alexander A Myburg, Don A Cowan
Lignocellulosic biomass is a promising feedstock for the manufacture of biodegradable and renewable bioproducts. However, the complex lignocellulosic polymeric structure of woody tissue is difficult to access without extensive industrial pre-treatment. Enzyme processing of partly depolymerised biomass is an established technology, and there is evidence that high temperature (extremely thermophilic) lignocellulose degrading enzymes [carbohydrate active enzymes (CAZymes)] may enhance processing efficiency. However, wild-type thermophilic CAZymes will not necessarily be functionally optimal under industrial pre-treatment conditions...
November 6, 2017: Extremophiles: Life Under Extreme Conditions
Yanzheng Jin, Shidong Qin, Hai Gao, Guoliang Zhu, Wei Wang, Weiming Zhu, Yi Wang
To obtain new bioactive natural products, the effect of acidic stress on the metabolites of an aciduric fungus was investigated. This fungus, Penicillium sp. OUCMDZ-4736, which was isolated from the sediment around roots of mangrove (Acanthus ilicifolius), produced different compounds and higher yields under pH 2.5 than under neutral conditions. Using spectroscopic analyses and calculations, three new anthraquinone derivatives (1-3) were isolated and identified from the acidic fermentation broth (pH 2.5) of OUCMDZ-4736...
November 4, 2017: Extremophiles: Life Under Extreme Conditions
Alan T Bull, Hamidah Idris, Roy Sanderson, Juan Asenjo, Barbara Andrews, Michael Goodfellow
The data reported in this paper are among the first relating to the microbiology of hyper-arid, very high altitude deserts and they provide base line information on the structure of actinobacterial communities. The high mountain Cerro Chajnantor landscape of the Central Andes in northern Chile is exposed to the world's most intense levels of solar radiation and its impoverished soils are severely desiccated. The purpose of this research was to define the actinobacterial community structures in soils at altitudes ranging from 3000 to 5000 m above sea level...
November 3, 2017: Extremophiles: Life Under Extreme Conditions
Liang Shen, Yongqin Liu, Ninglian Wang, Nianzhi Jiao, Baiqing Xu, Xiaobo Liu
It has been suggested that the cryosphere is a new biome uniquely dominated by microorganisms, although the ecological characteristics of these cold-adapted bacteria are not well understood. We investigated the vertical variation with depth of the proportion of pigmented bacteria recovered from an ice core drilled in the Yuzhufeng Glacier, Tibetan Plateau. A total of 25,449 colonies were obtained from 1250 ice core sections. Colonies grew on only one-third of the inoculated Petri dishes, indicating that although the ice core harbored abundant culturable bacteria, bacteria could not be isolated from every section...
October 25, 2017: Extremophiles: Life Under Extreme Conditions
Christos A Christakis, Paraskevi N Polymenakou, Manolis Mandalakis, Paraskevi Nomikou, Jon Bent Kristoffersen, Danai Lampridou, Georgios Kotoulas, Antonios Magoulas
Over the last decades, there has been growing interest about the ecological role of hydrothermal sulfide chimneys, their microbial diversity and associated biotechnological potential. Here, we performed dual-index Illumina sequencing of bacterial and archaeal communities on active and inactive sulfide chimneys collected from the Kolumbo hydrothermal field, situated on a geodynamic convergent setting. A total of 15,701 OTUs (operational taxonomic units) were assigned to 56 bacterial and 3 archaeal phyla, 133 bacterial and 16 archaeal classes...
October 25, 2017: Extremophiles: Life Under Extreme Conditions
Naoko Okibe, Daisuke Nakayama, Takahiro Matsumoto
The acidophilic, Fe(III)-reducing heterotrophic bacteria Acidocella aromatica PFBC(T) and Acidiphilium cryptum SJH were utilized to produce palladium (Pd) bionanoparticles via a simple 1-step microbiological reaction. Monosaccharide (or intracellular NADH)-dependent reactions lead to visualization of intra/extra-cellular enzymatic Pd(0) nucleation. Formic acid-dependent reactions proceeded via the first slow Pd(0) nucleation phase and the following autocatalytic Pd(II) reduction phase regardless of the presence or viability of the cells...
November 2017: Extremophiles: Life Under Extreme Conditions
Raza Ashraf, Naeem Rashid, Tamotsu Kanai, Tadayuki Imanaka, Muhammad Akhtar
Genome sequence of Pyrobaculum calidifontis, a hyperthermophilic archaeon, harbors three open-reading frames annotated as alcohol dehydrogenases. One of them, Pcal_1311, does not display a significantly high homology with any of the characterized alcohol dehydrogenases. Highest homology of 38% was found with the characterized counterpart from Geobacillus stearothermophilus. To examine the biochemical properties of Pcal_1311, we have cloned and functionally expressed the gene in Escherichia coli. Purified recombinant Pcal_1311 catalyzed the NAD(H)-dependent oxidation of various alcohols and reduction of aldehydes, with a marked preference for substrates with functional group at the terminal carbon...
November 2017: Extremophiles: Life Under Extreme Conditions
Katri Eskelin, Mirka Lampi, Florian Meier, Evelin Moldenhauer, Dennis H Bamford, Hanna M Oksanen
Viruses come in various shapes and sizes, and a number of viruses originate from extremities, e.g. high salinity or elevated temperature. One challenge for studying extreme viruses is to find efficient purification conditions where viruses maintain their infectivity. Asymmetrical flow field-flow fractionation (AF4) is a gentle native chromatography-like technique for size-based separation. It does not have solid stationary phase and the mobile phase composition is readily adjustable according to the sample needs...
November 2017: Extremophiles: Life Under Extreme Conditions
Almudena Rivadeneyra, Alejandro Gonzalez-Martinez, Gabriela R Portela, Daniel J Martin-Ramos, Jesús Gonzalez-Lopez, María A Rivadeneyra
The ability of Halomonas maura to bioprecipitate carbonate and sulphate crystals in solid media at different manganese concentrations has been demonstrated in this study for the first time. The precipitated minerals were studied by X-ray diffraction, scanning and transmission electron microscopy, and energy-dispersive X-ray spectroscopy. The precipitated minerals were different based on the manganese concentration present in the medium and the incubation time. In the absence of manganese, H. maura formed pseudokutnahorite crystals; in the presence of manganese, the concentration in the culture medium determined the precipitation carbonates, such as rhodochrosite and dolomites...
November 2017: Extremophiles: Life Under Extreme Conditions
Dahe Zhao, Sumit Kumar, Jian Zhou, Rui Wang, Ming Li, Hua Xiang
Bioremediation in hypersaline environments is particularly challenging since the microbes that tolerate such harsh environments and degrade pollutants are quite scarce. Haloarchaea, however, due to their inherent ability to grow at high salt concentrations, hold great promise for remediating the contaminated hypersaline sites. This study aimed to isolate and characterize novel haloarchaeal strains with potentials in hydrocarbon degradation. A haloarchaeal strain IM1011 was isolated from Changlu Tanggu saltern near Da Gang Oilfield in Tianjin (China) by enrichment culture in hypersaline medium containing hexadecane...
November 2017: Extremophiles: Life Under Extreme Conditions
Laura Selbmann, Silvano Onofri, Claudia Coleine, Pietro Buzzini, Fabiana Canini, Laura Zucconi
A wide sampling of rocks, colonized by microbial epi-endolithic communities, was performed along an altitudinal gradient from sea level to 3600 m asl and sea distance from the coast to 100 km inland along the Victoria Land Coast, Antarctica. Seventy-two rock samples of different typology, representative of the entire survey, were selected and studied using denaturing gradient gel electrophoresis to compare variation in fungal diversity according to environmental conditions along this altitudinal and sea distance transect...
November 2017: Extremophiles: Life Under Extreme Conditions
Vladimir S Cheptsov, Elena A Vorobyova, Natalia A Manucharova, Mikhail V Gorlenko, Anatoli K Pavlov, Maria A Vdovina, Vladimir N Lomasov, Sergey A Bulat
This research aimed to investigate the viability and biodiversity of microbial communities within ancient Arctic permafrost after exposure to a gamma-radiation dose of 100 kGy at low temperature (- 50 °C), low pressure (1 Torr) and dehydration conditions. The main objective was to assess the possibility for long-term survival of Earth-bound microorganisms in the subsurface of Martian regolith or inside small space bodies at constant absorption and accumulation of the gamma radiation dose. Investigated microbial communities had shown high resistance to a simulated Martian environment...
November 2017: Extremophiles: Life Under Extreme Conditions
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