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Extremophiles: Life Under Extreme Conditions

Satoshi Wakai, Akihiro Abe, Sotaro Fujii, Kaoru Nakasone, Yoshihiro Sambongi
The soluble protein fraction of the extremely halophilic archaeon Haloarcula japonica exhibits substantial inorganic pyrophosphate (PPi) hydrolysis activity in the presence of 2-4 M NaCl (Wakai et al, J Biol Chem 288:29247-29251, 2013), which provides high ionic strength (2-4). In this study, much higher PPi hydrolysis activity was unexpectedly detected, even with 0 M NaCl in the presence of 100-200 mM MgSO4, providing a much lower ionic strength of 0.4-0.8, in the same protein fraction. Na(+) and Mg(2+) ions were required for activity under high and low ionic strength conditions, respectively...
February 17, 2017: Extremophiles: Life Under Extreme Conditions
Juan José Marizcurrena, María A Morel, Victoria Braña, Danilo Morales, Wilner Martinez-López, Susana Castro-Sowinski
Ultraviolet (UV) light irradiation has serious consequences for cell survival, including DNA damage by formation of cyclobutane pyrimidine dimers (CPD) and pyrimidine (6,4) pyrimidone photoproducts. In general, the Nucleotide Excision Repair pathway repairs these lesions; however, all living forms, except placental mammals and some marsupials, produce a flavoprotein known as photolyase that directly reverses these lesions. The aim of this work was the isolation and identification of Antarctic UVC-resistant bacteria, and the search for novel photolyases...
February 11, 2017: Extremophiles: Life Under Extreme Conditions
Takumi Yamashiro, Kousaku Murata, Shigeyuki Kawai
Deinococcus radiodurans is highly resistant to ionizing radiation and UV radiation, and oxidative stress caused by such radiations. NADP(H) seems to be important for this resistance (Slade and Radman, Microbiol Mol Biol Rev 75:133-191; Slade, Radman, Microbiol Mol Biol Rev 75:133-191, 2011), but the mechanism underlying the generation of NADP(H) or NAD(H) in D. radiodurans has not fully been addressed. Intracellular concentrations of NAD(+), NADH, NADP(+), and NADPH in D. radiodurans are also not determined yet...
January 12, 2017: Extremophiles: Life Under Extreme Conditions
Michael J Morten, Roland Gamsjaeger, Liza Cubeddu, Ruvini Kariawasam, Jose Peregrina, J Carlos Penedo, Malcolm F White
Single-stranded DNA-binding proteins (SSBs), including replication protein A (RPA) in eukaryotes, play a central role in DNA replication, recombination, and repair. SSBs utilise an oligonucleotide/oligosaccharide-binding (OB) fold domain to bind DNA, and typically oligomerise in solution to bring multiple OB fold domains together in the functional SSB. SSBs from hyperthermophilic crenarchaea, such as Sulfolobus solfataricus, have an unusual structure with a single OB fold coupled to a flexible C-terminal tail...
January 10, 2017: Extremophiles: Life Under Extreme Conditions
Li-Jing Kang, Zi-Tong Meng, Chen Hu, Yan Zhang, Hai-Lun Guo, Qing Li, Mu Li
Organic solvent-tolerant esterases are proven to be excellent biocatalysts in chemical and pharmaceutical industries. A novel organic solvent-tolerant esterase gene, lip2, was isolated from filamentous fungi Monascus purpureus M7. The sequence analysis suggested that lip2 has a conserved "GDSL" motif near the active center. The multiple-sequence alignment and phylogenetic analysis revealed that Lip2 displayed two unique amino-acid sequence motifs that clearly separate it from any other previously described lipase family...
January 6, 2017: Extremophiles: Life Under Extreme Conditions
Riegardt M Johnson, Jean-Baptiste Ramond, Eoin Gunnigle, Mary Seely, Don A Cowan
The central Namib Desert is hyperarid, where limited plant growth ensures that biogeochemical processes are largely driven by microbial populations. Recent research has shown that niche partitioning is critically involved in the assembly of Namib Desert edaphic communities. However, these studies have mainly focussed on the Domain Bacteria. Using microbial community fingerprinting, we compared the assembly of the bacterial, fungal and archaeal populations of microbial communities across nine soil niches from four Namib Desert soil habitats (riverbed, dune, gravel plain and salt pan)...
January 5, 2017: Extremophiles: Life Under Extreme Conditions
Daniel Bollschweiler, Miroslava Schaffer, C Martin Lawrence, Harald Engelhardt
Most halophilic Archaea of the class Halobacteriaceae depend on the presence of several molar sodium chloride for growth and cell integrity. This poses problems for structural studies, particularly for electron microscopy, where the high salt concentration results in diminished contrast. Since cryo-electron microscopy of intact cells provides new insights into the cellular and molecular organization under close-to-live conditions, we evaluated strategies and conditions to make halophilic microbes available for investigations in situ...
January 3, 2017: Extremophiles: Life Under Extreme Conditions
Taka-Aki Kuribayashi, Sotaro Fujii, Misa Masanari, Masaru Yamanaka, Satoshi Wakai, Yoshihiro Sambongi
Shewanella species are widely distributed in sea, brackish, and fresh water areas, growing psychrophilically or mesophilically, and piezophilically or piezo-sensitively. Here, membrane-bound 5'-nucleotidases (NTases) from deep-sea Shewanella violacea and brackish water Shewanella amazonensis were examined from the aspect of NaCl tolerance to gain an insight into protein stability against salt. Both NTases were single polypeptides with molecular masses of ~59 kDa, as determined on mass spectroscopy. They similarly required 10 mM MgCl2 for their activities, and they exhibited the same pH dependency and substrate specificity for 5'-nucleotides...
January 3, 2017: Extremophiles: Life Under Extreme Conditions
Alexander Yu Merkel, Nikolay V Pimenov, Igor I Rusanov, Alexander I Slobodkin, Galina B Slobodkina, Ivan Yu Tarnovetckii, Evgeny N Frolov, Arseny V Dubin, Anna A Perevalova, Elizaveta A Bonch-Osmolovskaya
Microbial communities of Kamchatka Peninsula terrestrial hot springs were studied using molecular, radioisotopic and cultural approaches. Analysis of 16S rRNA gene fragments performed by means of high-throughput sequencing revealed that aerobic autotrophic sulfur-oxidizing bacteria of the genus Sulfurihydrogenibium (phylum Aquificae) dominated in a majority of streamers. Another widely distributed and abundant group was that of anaerobic bacteria of the genus Caldimicrobium (phylum Thermodesulfobacteria). Archaea of the genus Vulcanisaeta were abundant in a high-temperature, slightly acidic hot spring, where they were accompanied by numerous Nanoarchaeota, while the domination of uncultured Thermoplasmataceae A10 was characteristic for moderately thermophilic acidic habitats...
December 27, 2016: Extremophiles: Life Under Extreme Conditions
Garabed Antranikian
No abstract text is available yet for this article.
December 24, 2016: Extremophiles: Life Under Extreme Conditions
Ivana Cavello, Agustín Albanesi, Dante Fratebianchi, Gabriela Garmedia, Silvana Vero, Sebastián Cavalitto
One hundred and three yeasts isolated from soil samples from King George Island and Tierra del Fuego province were screened in relation with their capability to produce pectinolytic enzymes. Although all the yeasts showed well-developed colonies at 20 °C, only eight showed a clear halo around the colony, indicative of pectin degradation. A secondary screening demonstrated that only four yeasts were capable to produce pectinases at low temperatures (8 °C). It could be seen that the selected yeasts were able to grow and produce high levels of polygalacturonase activity when submerged fermentations were performed using pectin-containing fruit wastes as substrates...
December 21, 2016: Extremophiles: Life Under Extreme Conditions
M Bacior, P Nowak, H Harańczyk, S Patryas, P Kijak, A Ligęzowska, M A Olech
Gaseous phase hydration effect of extremely dehydrated thallus of the Antarctic lichenized fungus Turgidosculum complicatulum and of green alga Prasiola crispa was observed using hydration kinetics, sorption isotherm, (1)H-NMR spectroscopy and relaxometry. Three bound water fractions were distinguished: (1) very tightly bound water, (2) tightly bound water and (3) a loosely bound water fraction detected at higher levels of hydration. Sorption isotherm was sigmoidal in form and well fitted using Dent model. The relative mass of water saturating primary water binding sites was ΔM/m 0 = 0...
December 20, 2016: Extremophiles: Life Under Extreme Conditions
Dovilė Barcytė, Linda Nedbalová
The aim of this study was to reveal the taxonomic position and phylogenetic relationships of the dominant planktic algae in two acid metal-rich lakes of different origin (Hromnice Lake and Plešné Lake, Czech Republic) and to investigate their morphology and ultrastructure under natural and laboratory conditions. Phylogenetic analyses (18S rRNA and ITS-2) revealed that the strain isolated from Hromnice Lake belongs to the species Coccomyxa elongata, while Coccomyxa from Plešné Lake was described as a new species C...
December 9, 2016: Extremophiles: Life Under Extreme Conditions
Alejandro Arce-Rodríguez, Fernando Puente-Sánchez, Roberto Avendaño, Eduardo Libby, Leonardo Rojas, Juan Carlos Cambronero, Dietmar H Pieper, Kenneth N Timmis, Max Chavarría
Whether the extreme conditions of acidity and heavy metal pollution of streams and rivers originating in pyritic formations are caused primarily by mining activities or by natural activities of metal-oxidizing microbes living within the geological formations is a subject of considerable controversy. Most microbiological studies of such waters have so far focused on acid mine drainage sites, which are heavily human-impacted environments, so it has been problematic to eliminate the human factor in the question of the origin of the key metal compounds...
December 8, 2016: Extremophiles: Life Under Extreme Conditions
Hiroki Okanishi, Kwang Kim, Ryoji Masui, Seiki Kuramitsu
Recent studies have revealed the physiological significance of post-translational lysine acylations such as acetylation in the regulation of various cellular processes. Here, we characterized lysine propionylation, a recently discovered post-translational acylation, in five representative bacteria: Geobacillus kaustophilus, Thermus thermophilus, Escherichia coli, Bacillus subtilis, and Rhodothermus marinus. Using antibody-based propionyl peptide enrichment followed by identification with nano-liquid chromatography tandem mass spectrometry, we showed that proteins were subject to lysine propionylation in all five bacterial species analyzed...
December 7, 2016: Extremophiles: Life Under Extreme Conditions
Dongmei Han, Zhaohui Xu
To fully unlock the biotechnological potentials of Thermotoga species, this study aimed to expand the genetic toolbox of Thermotoga by developing a new selective system. The developed system was composed of two components: a recipient strain bearing a deletion in its orotate phosphoribosyltransferase gene pyrE and a shuttle vector expressing a heterologous pyrE as the selectable marker. A spontaneous uracil auxotroph, T. sp. strain RQ7-15, was isolated at 70 °C with 2 mg/ml 5-fluoroorotic acid. The mutant carried a 112 bp deletion in pyrE and was a suitable recipient strain...
December 7, 2016: 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
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