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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...
May 24, 2018: Extremophiles: Life Under Extreme Conditions
Manuela Iovinella, Ayla Eren, Gabriele Pinto, Antonino Pollio, Seth J Davis, Paola Cennamo, Claudia Ciniglia
Cyanidiophytina are a group of polyextremophilic red algae with a worldwide, but discontinuous colonization. They are restricted to widely dispersed hot springs, geothermal habitats, and also some human-altered environments. Cyanidiophytina are predominant where pH is prohibitive for the majority of eukaryotes (pH 0.5-3). Turkey is characterized by areas rich in volcanic activity separated by non-volcanic areas. Here we show that Cyanidiophycean populations are present in thermal baths located around Turkey on neutral/alkaline soils...
May 19, 2018: Extremophiles: Life Under Extreme Conditions
Hovik Panosyan, Paola Di Donato, Annarita Poli, Barbara Nicolaus
The thermal ecosystems, including geothermal springs, are proving to be source of thermophiles able to produce extracellular polysaccharides (EPSs). Among the sixteen thermophilic bacilli isolated from sediment sampled from Arzakan geothermal spring, Armenia, two best EPSs producer strains were identified based on 16S rRNA gene sequence analysis and phenotypic characteristics, and designated as Geobacillus thermodenitrificans ArzA-6 and Geobacillus toebii ArzA-8 strains. EPSs production was investigated under different time, temperature and culture media's composition...
May 19, 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 northwest 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...
April 30, 2018: Extremophiles: Life Under Extreme Conditions
José O Bonilla, Daniel G Kurth, Fabricio D Cid, José H Ulacco, Raúl A Gil, Liliana B Villegas
The acid mine drainage that originates in the abandoned gold mine in San Luis, Argentina, is released into La Carolina stream. The aim of this study was to determine the influence of this mine drainage on the physicochemical parameters of the area studied and on both prokaryotic and eukaryotic community structure. In addition, specific relationships between microbial taxonomic groups and physicochemical parameters were established. The drainage that flows into La Carolina stream acidifies the stream and increases its sulfate, Zn, Cd and Te concentrations...
April 28, 2018: Extremophiles: Life Under Extreme Conditions
Ashok Bankar, Smita Zinjarde, Manisha Shinde, Gita Gopalghare, Ameeta Ravikumar
Heavy metal tolerance of two marine strains of Yarrowia lipolytica was tested on solid yeast extract peptone dextrose agar plates. Based on minimum inhibitory concentration esteems, it is inferred that the two strains of Y. lipolytica were tolerant to heavy metals such as Pb(II), Cr(III), Zn(II), Cu(II), As(V), and Ni(II) ions. The impact of various heavy metal concentrations on the growth kinetics of Y. lipolytica was likewise assessed. With increased heavy metal concentration, the specific growth rate was reduced with delayed doubling time...
March 29, 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
Rok Sekirnik, Sarah E Wilkins, Jacob Bush, Hanna Tarhonskaya, Martin Münzel, Aayan Hussein, Emily Flashman, Shabaz Mohammed, Michael A McDonough, Christoph Loenarz, Christopher J Schofield
YcfD from Escherichia coli is a homologue of the human ribosomal oxygenases NO66 and MINA53, which catalyse histidyl-hydroxylation of the 60S subunit and affect cellular proliferation (Ge et al., Nat Chem Biol 12:960-962, 2012). Bioinformatic analysis identified a potential homologue of ycfD in the thermophilic bacterium Rhodothermus marinus (ycfDRM ). We describe studies on the characterization of ycfDRM , which is a functional 2OG oxygenase catalysing (2S,3R)-hydroxylation of the ribosomal protein uL16 at R82, and which is active at significantly higher temperatures than previously reported for any other 2OG oxygenase...
May 2018: Extremophiles: Life Under Extreme Conditions
Kun Chen, Qingshan Mo, Huan Liu, Feiyan Yuan, Haonan Chai, Fuping Lu, Huitu Zhang
A psychrophilic extracellular protease was isolated from the marine bacterium Planococcus sp. M7 found in the deep-sea mud of the Southern Indian Ocean. The mature protease is about 43 kDa and contains 389 amino acids. Sequence alignment revealed that the protease whose catalytic triad was comprised of Ser224, Lys249, and Gln253 contains a catalytic module belonging to the serralysin-type protease family 41, and displays 46.55% identity with the experimentally verified serine protease from Bacillus subtilis str...
May 2018: Extremophiles: Life Under Extreme Conditions
Fernanda P Cid, Fumito Maruyama, Kazunori Murase, Steffen P Graether, Giovanni Larama, Leon A Bravo, Milko A Jorquera
Genome analyses are being used to characterize plant growth-promoting (PGP) bacteria living in different plant compartiments. In this context, we have recently isolated bacteria from the phyllosphere of an Antarctic plant (Deschampsia antarctica) showing ice recrystallization inhibition (IRI), an activity related to the presence of antifreeze proteins (AFPs). In this study, the draft genomes of six phyllospheric bacteria showing IRI activity were sequenced and annotated according to their functional gene categories...
May 2018: Extremophiles: Life Under Extreme Conditions
Kai-Hui Liu, Xiao-Wei Ding, Nimaichand Salam, Bo Zhang, Xiao-Fei Tang, Baiwan Deng, Wen-Jun Li
Fungal communities represent an indispensable part of the geothermal spring ecosystem; however, studies on fungal community within hot springs are still scant. Here, we used Illumina HiSeq 2500 sequencing to detect fungal community diversity in extremely acidic hot springs (pH < 4) and neutral and alkaline springs (pH > 6) of Tengchong-indicated by the presence of over 0.75 million valid reads. These sequences were phylogenetically assigned to 5 fungal phyla, 67 order, and 375 genera, indicating unexpected fungal diversity in the hot springs...
May 2018: Extremophiles: Life Under Extreme Conditions
Kerstin Kruse, Ralf Salzer, Friederike Joos, Beate Averhoff
The traffic ATPase PilF of Thermus thermophilus powers pilus assembly as well as uptake of DNA. PilF differs from other traffic ATPases by a triplicated general secretory pathway II, protein E, N-terminal domain (GSPIIABC). We investigated the in vivo and in vitro roles of the GSPII domains, the Walker A motif and a catalytic glutamate by analyzing a set of PilF deletion derivatives and pilF mutants. Here, we report that PilF variants devoid of the first two or all three GSPII domains do not form stable hexamers indicating a role of the triplicated GSPII domain in complex formation and/or stability...
May 2018: Extremophiles: Life Under Extreme Conditions
Sergei V Kalenov, Mariia G Gordienko, Ekaterina D Murzina, Daniil Y Poberezhniy, Dmitry V Baurin, Natalia E Suzina, Alexander N Morozov, Liubov M Yakubovich, Alexey A Belov, Victor I Panfilov, Oksana V Yarovaya, Michail M Il'in, Vladimir V Sorokin, Dmitry A Skladnev
Spray drying is appropriate for the preservation of halophilic microorganisms due to the nature of these microorganisms, as they survive in adverse environmental conditions by being encapsulated in salt crystals. Artificial neural networks were in this study used to optimize practically significant spray-drying regimes of the C50 -carotenoids producer Halobacterium salinarum. Immediately after drying, the samples contained up to 54% halobacterial biomass and less than 5% moisture, and the level of preservation of carotenoids was 95-97%...
May 2018: Extremophiles: Life Under Extreme Conditions
D'Arcy R Meyer-Dombard, Caitlin P Casar, Alexander G Simon, Dawn Cardace, Matthew O Schrenk, Carlo A Arcilla
Terrestrial serpentinizing systems harbor microbial subsurface life. Passive or active microbially mediated iron transformations at alkaline conditions in deep biosphere serpentinizing ecosystems are understudied. We explore these processes in the Zambales (Philippines) and Coast Range (CA, USA) ophiolites, and associated surface ecosystems by probing the relevance of samples acquired at the surface to in situ, subsurface ecosystems, and the nature of microbe-mineral associations in the subsurface. In this pilot study, we use microcosm experiments and batch culturing directed at iron redox transformations to confirm thermodynamically based predictions that iron transformations may be important in subsurface serpentinizing ecosystems...
May 2018: Extremophiles: Life Under Extreme Conditions
Yuzhi Wu, Jian-Wen Qiu, Pei-Yuan Qian, Yong Wang
In deep-sea cold seeps, microbial communities are shaped by geochemical components in seepage solutions. In the present study, we report the composition of microbial communities and potential metabolic activities in the surface sediment of Jiaolong cold seep at the northern South China Sea. Pyrosequencing of 16S rRNA gene amplicons revealed that a majority of the microbial inhabitants of the surface layers (0-6 cm) were sulfur oxidizer bacteria Sulfurimonas and archaeal methane consumer ANME-1, while sulfate reducer bacteria SEEP-SRB1, ANME-1 and ANME-2 dominated the bottom layers (8-14 cm)...
May 2018: Extremophiles: Life Under Extreme Conditions
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