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Extremophiles: Life Under Extreme Conditions

Ali H A Elbehery, Ramy K Aziz, Rania Siam
Mobile genetic elements are major agents of genome diversification and evolution. Limited studies addressed their characteristics, including abundance, and role in extreme habitats. One of the rare natural habitats exposed to multiple-extreme conditions, including high temperature, salinity and concentration of heavy metals, are the Red Sea brine pools. We assessed the abundance and distribution of different mobile genetic elements in four Red Sea brine pools including the world's largest known multiple-extreme deep-sea environment, the Red Sea Atlantis II Deep...
December 3, 2016: Extremophiles: Life Under Extreme Conditions
Isabel Natalia Sierra-Garcia, Bruna M Dellagnezze, Viviane P Santos, Michel R Chaves B, Ramsés Capilla, Eugenio V Santos Neto, Neil Gray, Valeria M Oliveira
Microorganisms have shown their ability to colonize extreme environments including deep subsurface petroleum reservoirs. Physicochemical parameters may vary greatly among petroleum reservoirs worldwide and so do the microbial communities inhabiting these different environments. The present work aimed at the characterization of the microbiota in biodegraded and non-degraded petroleum samples from three Brazilian reservoirs and the comparison of microbial community diversity across oil reservoirs at local and global scales using 16S rRNA clone libraries...
December 3, 2016: Extremophiles: Life Under Extreme Conditions
Graciéle C A de Menezes, Valéria M Godinho, Bárbara A Porto, Vívian N Gonçalves, Luiz H Rosa
In the present study, we have identified and characterised a new snow resident ascomycete blue stain fungus from Antarctica named Antarctomyces pellizariae sp. nov. Menezes, Godinho, Porto, Gonçalves and Rosa, using polyphasic taxonomy techniques. This fungal species was recovered from the seasonal snow of the Antarctic Peninsula. Antarctomyces pellizariae displayed different macro- and micromorphology when compared with A. psychrotrophicus Stchigel and Guarro, the only other Antarctomyces species reported until date...
November 30, 2016: Extremophiles: Life Under Extreme Conditions
Yolanda García-Huante, Maribel Cayetano-Cruz, Alejandro Santiago-Hernández, Claudia Cano-Ramírez, Rodolfo Marsch-Moreno, Jorge E Campos, Guillermo Aguilar-Osorio, Claudia G Benitez-Cardoza, Sergio Trejo-Estrada, María Eugenia Hidalgo-Lara
A hyperthermophilic and thermostable xylanase of 82 kDa (TtXynA) was purified from the culture supernatant of T. terrestris Co3Bag1, grown on carboxymethyl cellulose (CMC), and characterized biochemically. TtXynA showed optimal xylanolytic activity at pH 5.5 and at 85 °C, and retained more than 90% of its activity at a broad pH range (4.5-10). The enzyme is highly thermostable with a half-life of 23.1 days at 65 °C, and active in the presence of several metal ions. Circular dichroism spectra strongly suggest the enzyme gains secondary structures when temperature increases...
November 29, 2016: Extremophiles: Life Under Extreme Conditions
Robin Baginski, Monika Sommerhalter
An enzyme with catechol oxidase activity was identified in Thermomicrobium roseum extracts via solution assays and activity-stained SDS-PAGE. Yet, the genome of T. roseum does not harbor a catecholase gene. The enzyme was purified with two anion exchange chromatography steps and ultimately identified to be a manganese catalase with additional peroxidase and catecholase activity. Catalase activity (6280 ± 430 IU/mg) clearly dominated over pyrogallol peroxidase (231 ± 53 IU/mg) and catecholase (3.07 ± 0...
November 29, 2016: Extremophiles: Life Under Extreme Conditions
Linda Nedbalová, Martin Mihál, Jana Kvíderová, Lenka Procházková, Tomáš Řezanka, Josef Elster
The aim of this study was to assess the phylogenetic relationships, ecology and ecophysiological characteristics of the dominant planktic algae in ice-covered lakes on James Ross Island (northeastern Antarctic Peninsula). Phylogenetic analyses of 18S rDNA together with analysis of ITS2 rDNA secondary structure and cell morphology revealed that the two strains belong to one species of the genus Monoraphidium (Chlorophyta, Sphaeropleales, Selenastraceae) that should be described as new in future. Immotile green algae are thus apparently capable to become the dominant primary producer in the extreme environment of Antarctic lakes with extensive ice-cover...
November 25, 2016: Extremophiles: Life Under Extreme Conditions
Yuqi Fan, Takayuki Hoshino, Akira Nakamura
There are 12 putative toxin-antitoxin (TA) loci in the Thermus thermophilus HB27 genome, including four VapBC and three HicBA families. Expression of these seven putative toxin genes in Escherichia coli demonstrated that one putative VapC toxin TTC0125 and two putative HicA toxins, TTC1395 and TTC1705, inhibited cell growth, and co-expression with cognate antitoxin genes rescued growth, indicating that these genes function as TA loci. In vitro analysis with the purified TTC0125 and total RNA/mRNA from E. coli and T...
November 16, 2016: Extremophiles: Life Under Extreme Conditions
P Arulazhagan, K Al-Shekri, Q Huda, J J Godon, J M Basahi, D Jeyakumar
The present study aims at analyzing the degradation of polycyclic aromatic hydrocarbons (PAHs) at acidic conditions (pH = 2) by acidophilic Stenotrophomonas maltophilia strain AJH1 (KU664513). The strain AJH1 was obtained from an enrichment culture obtained from soil samples of mining area in the presence of PAH as sole sources of carbon and energy. Strain AJH1was able to degrade low (anthracene, phenanthrene, naphthalene, fluorene) and high (pyrene, benzo(e)pyrene and benzo(k)fluoranthene) molecular weight PAHs in acidophilic mineral salt medium at pH 2, with removal rates of up to 95% (LMW PAH) and 80% (HMW PAH), respectively...
November 16, 2016: Extremophiles: Life Under Extreme Conditions
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November 9, 2016: Extremophiles: Life Under Extreme Conditions
Carola Schröder, Viktoria-Astrid Janzer, Georg Schirrmacher, Jörg Claren, Garabed Antranikian
Two genes (agal1 and agal2) encoding α-galactosidases were identified by sequence-based screening approaches. The gene agal1 was identified from a data set of a sequenced hot spring metagenome, and the deduced amino-acid sequence exhibited 99% identity to an α-galactosidase from the thermophilic bacterium Dictyoglomus thermophilum. The gene agal2 was identified from the whole genome sequence of the thermophile Meiothermus ruber. The amino-acid sequences exhibited structural motifs typical for glycoside hydrolase (GH) family 36 members and were also differentiated into different subgroups of this family...
November 9, 2016: Extremophiles: Life Under Extreme Conditions
Benjamin H Meyer, Hosam Shams-Eldin, Sonja-Verena Albers
AglH, a predicted UDP-GlcNAc-1-phosphate:dolichyl phosphate GlcNAc-1-phosphotransferase, is initiating the protein N-glycosylation pathway in the thermoacidophilic crenarchaeon Sulfolobus acidocaldarius. AglH successfully replaced the endogenous GlcNAc-1-phosphotransferase activity of Alg7 in a conditional lethal Saccharomyces cerevisiae strain, in which the first step of the eukaryal protein N-glycosylation process was repressed. This study is one of the few examples of cross-domain complementation demonstrating a conserved polyprenyl phosphate transferase reaction within the eukaryal and archaeal domain like it was demonstrated for Methanococcus voltae (Shams-Eldin et al...
November 7, 2016: Extremophiles: Life Under Extreme Conditions
Xiaoben Jiang, Cristina D Takacs-Vesbach
The pH of the majority of thermal springs in Yellowstone National Park (YNP) is from 1 to 3 and 6 to 10; relatively few springs (~5%) have a pH range of 4-5. We used 16S rRNA gene pyrosequencing to investigate microbial communities sampled from four pH 4 thermal springs collected from four regions of YNP that differed in their fluid temperature and geochemistry. Our results revealed that the composition of bacterial communities varied among the sites, despite sharing similar pH values. The taxonomic composition and metabolic functional potential of the site with the lowest temperature (55 °C), a thermal spring from the Seven Mile Hole (SMH) area, were further investigated using shotgun metagenome sequencing...
November 2, 2016: Extremophiles: Life Under Extreme Conditions
Alina Ryabova, Kyosuke Mukae, Alexander Cherkasov, Richard Cornette, Elena Shagimardanova, Tetsuya Sakashita, Takashi Okuda, Takahiro Kikawada, Oleg Gusev
It is assumed that resistance to ionizing radiation, as well as cross-resistance to other abiotic stresses, is a side effect of the evolutionary-based adaptation of anhydrobiotic animals to dehydration stress. Larvae of Polypedilum vanderplanki can withstand prolonged desiccation as well as high doses of ionizing radiation exposure. For a further understanding of the mechanisms of cross-tolerance to both types of stress exposure, we profiled genome-wide mRNA expression patterns using microarray techniques on the chironomid larvae collected at different stages of desiccation and after exposure to two types of ionizing radiation-70 Gy of high-linear energy transfer (LET) ions ((4)He) and the same dose of low-LET radiation (gamma rays)...
November 2, 2016: Extremophiles: Life Under Extreme Conditions
Masahiro Ito, Yuka Takahashi
Prior to 2008, all previously studied conventional bacterial flagellar motors appeared to utilize either H(+) or Na(+) as coupling ions. Membrane-embedded stator complexes support conversion of energy using transmembrane electrochemical ion gradients. The main H(+)-coupled stators, known as MotAB, differ from Na(+)-coupled stators, PomAB of marine bacteria, and MotPS of alkaliphilic Bacillus. However, in 2008, a MotAB-type flagellar motor of alkaliphilic Bacillus clausii KSM-K16 was revealed as an exception with the first dual-function motor...
October 22, 2016: Extremophiles: Life Under Extreme Conditions
Lachin Mokhtarnejad, Mahdi Arzanlou, Asadollah Babai-Ahari, Simone Di Mauro, Andrea Onofri, Pietro Buzzini, Benedetta Turchetti
Urmia Lake, located in northwest Iran, is an oligotrophic and extremely hypersaline habitat that supports diverse forms of life. Owing to its unique biodiversity and special environmental conditions, Urmia Lake National Park has been designated as one of the biosphere reserves by UNESCO. This study was aimed to characterize basidiomycetous yeasts in hypersaline soils surrounding the Urmia Lake National Park using a polyphasic combination of molecular and physiological data. Soil samples were collected from eight sites in Lake Basin and six islands insides the lake...
October 21, 2016: Extremophiles: Life Under Extreme Conditions
Tetsuo Kubota, Hajime Matsushita, Takeo Tomita, Saori Kosono, Minoru Yoshida, Tomohisa Kuzuyama, Makoto Nishiyama
Regulation of amino acid metabolism (RAM) domains are widely distributed among prokaryotes. In most cases, a RAM domain fuses with a DNA-binding domain to act as a transcriptional regulator. The extremely thermophilic bacterium, Thermus thermophilus, only carries a single gene encoding a RAM domain-containing protein on its genome. This protein is a stand-alone RAM domain protein (SraA) lacking a DNA-binding domain. Therefore, we hypothesized that SraA, which senses amino acids through its RAM domain, may interact with other proteins to modify its functions...
October 19, 2016: Extremophiles: Life Under Extreme Conditions
Yoichiro Sogame, Jun Okada, Shingo Kikuta, Yugo Miyata, Richard Cornette, Oleg Gusev, Takahiro Kikawada
Larvae of the African midge Polypedilum vanderplanki show extreme desiccation tolerance, known as anhydrobiosis. Recently, the cultured cell line Pv11 was derived from this species; Pv11 cells can be preserved in the dry state for over 6 months and retain their proliferation potential. Here, we attempted to expand the use of Pv11 cells as a model to investigate the mechanisms underlying anhydrobiosis in P. vanderplanki. A newly developed vector comprising a constitutive promoter for the PvGapdh gene allowed the expression of exogenous proteins in Pv11 cells...
October 18, 2016: Extremophiles: Life Under Extreme Conditions
Asmaa R Abdel-Hamed, Dina M Abo-Elmatty, Juergen Wiegel, Noha M Mesbah
An extracellular, halophilic, alkalithermophilic serine protease from the halo-alkaliphilic Alkalibacillus sp. NM-Da2 was purified to homogeneity by ethanol precipitation and anion-exchange chromatography. The purified protease was a monomeric enzyme with an approximate molecular mass of 35 kDa and exhibited maximal activity at 2.7 M NaCl, pH(55 °C) 9 and 56 °C. The protease showed great temperature stability, retaining greater than 80 % of initial activity after 2 h incubation at 55 °C. The protease was also extremely pH tolerant, retaining 80 % of initial activity at pH(55 °C) 10...
October 18, 2016: Extremophiles: Life Under Extreme Conditions
Tamotsu Kanai, Ayako Yasukochi, Jan-Robert Simons, Joseph Walker Scott, Wakao Fukuda, Tadayuki Imanaka, Haruyuki Atomi
The maturation of [NiFe]-hydrogenases requires a number of accessory proteins, which include hydrogenase-specific endopeptidases. The endopeptidases carry out the final cleavage reaction of the C-terminal regions of [NiFe]-hydrogenase large subunit precursors. The hyperthermophilic archaeon Thermococcus kodakarensis harbors two [NiFe]-hydrogenases, a cytoplasmic Hyh and a membrane-bound Mbh, along with two putative hydrogenase-specific endopeptidase genes. In this study, we carried out a genetic examination on the two endopeptidase genes, TK2004 and TK2066...
October 13, 2016: Extremophiles: Life Under Extreme Conditions
D Y Sorokin, N A Chernyh
Propionate can be directly oxidized anaerobically with sulfate as e-acceptor at haloalkaline conditions either incompletely to acetate (an example is Desulfobulbus alkaliphilus), or completely (for example by the members of genus Desulfonatronobacter). An enrichment with propionate at methanogenic conditions (without sulfate) inoculated with mixed sediments from hypersaline soda lakes in Kulunda Steppe (Altai, Russia) resulted in a domination of a new member of Syntrophobacteraceae (Deltaproteobacteria) in a consortium with the haloalkaliphilic lithotrophic methanogen Methanocalculus alkaliphilus...
October 12, 2016: Extremophiles: Life Under Extreme Conditions
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