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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...
April 16, 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...
April 12, 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
Noor Haza Fazlin Hashim, Nor Muhammad Mahadi, Rosli Md Illias, Shevin Rizal Feroz, Farah Diba Abu Bakar, Abdul Munir Abdul Murad
Dienelactone hydrolase, an α/β hydrolase enzyme, catalyzes the hydrolysis of dienelactone to maleylacetate, an intermediate for the Krebs cycle. Genome sequencing of the psychrophilic yeast, Glaciozyma antarctica predicted a putative open reading frame (ORF) for dienelactone hydrolase (GaDlh) with 52% sequence similarity to that from Coniophora puteana. Phylogenetic tree analysis showed that GaDlh is closely related to other reported dienelactone hydrolases, and distantly related to other α/β hydrolases...
March 20, 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...
March 9, 2018: Extremophiles: Life Under Extreme Conditions
Ceren Daskaya-Dikmen, Funda Karbancioglu-Guler, Beraat Ozcelik
The present study was performed to screen for psychrophilic yeasts that are able to secrete cold active enzymes. Yeast isolates were obtained from environmental samples from northern Turkey and examined for enzyme production at low temperatures. The isolates which were capable of cold active enzyme production on plates were identified by molecular identification techniques. It has been found that the isolates belonged to three genera of yeasts, i.e., Rhodosporidiobolus, Cystofilobasidium and Yamadazyma. The isolates were then fermented in different media at 15 °C and the pectinase, amylase and protease activities were determined in the range of 0...
March 7, 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...
March 1, 2018: Extremophiles: Life Under Extreme Conditions
Ryan Catchpole, Aurore Gorlas, Jacques Oberto, Patrick Forterre
Hyperthermophilic microorganisms are an important asset in the toolkits of biotechnologists, biochemists and evolutionary biologists. The anaerobic archaeon, Thermococcus kodakarensis, has become one of the most useful hyperthermophilic model species, not least due to its natural competence and genetic tractability. Despite this, the range of genetic tools available for T. kodakarensis remains limited. Using sequencing and phylogenetic analyses, we determined that the rolling-circle replication origin of the cryptic mini-plasmid pTP2 from T...
March 1, 2018: Extremophiles: Life Under Extreme Conditions
Christos A Christakis, Paraskevi N Polymenakou, Manolis Mandalakis, Paraskevi Nomikou, Jon Bent Kristoffersen, Danai Lampridou, Georgios Kotoulas, Antonios Magoulas
In the original publication there is a mistake in the supplementary material. The correct supplementary material is provided in this correction article.
March 1, 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...
February 28, 2018: Extremophiles: Life Under Extreme Conditions
Mariarosaria De Falco, Federica Massa, Mosè Rossi, Mariarita De Felice
ATPase/Helicases and nucleases play important roles in DNA end-resection, a critical step during homologous recombination repair in all organisms. In hyperthermophilic archaea the exo-endonuclease NurA and the ATPase HerA cooperate with the highly conserved Mre11-Rad50 complex in 3' single-stranded DNA (ssDNA) end processing to coordinate repair of double-stranded DNA breaks. Little is known, however, about the assembly mechanism and activation of the HerA-NurA complex. In this study we demonstrate that the NurA exonuclease activity is inhibited by the Sulfolobus solfataricus RecQ-like Hel112 helicase...
February 27, 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...
February 23, 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...
February 20, 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%...
February 17, 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...
February 15, 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)...
February 13, 2018: Extremophiles: Life Under Extreme Conditions
Sergey Y But, Natalia P Solntseva, Svetlana V Egorova, Ildar I Mustakhimov, Valentina N Khmelenina, Alexander Reshetnikov, Yuri A Trotsenko
Four enzymes involved in sucrose metabolism: sucrose phosphate synthase (Sps), sucrose phosphate phosphatase (Spp), sucrose synthase (Sus) and fructokinase (FruK), were obtained as his-tagged proteins from the moderately thermophilic methanotroph Methylocaldum szegediense O12. Sps, Spp, FruK and Sus demonstrated biochemical properties similar to those of other bacterial counterparts, but the translated amino acid sequences of Sps and Spp displayed high divergence from the respective microbial enzymes. The Sus of M...
February 13, 2018: Extremophiles: Life Under Extreme Conditions
Noora Barzkar, Ahmad Homaei, Roohullah Hemmati, Seema Patel
Thermostable proteases are important in biotechnological and industrial sectors, due to their stability against denaturing agents and chemicals. The feature that gives them such unique applicability is their reaction at high temperatures, which affords a high concentration of substrate, and less risk of microbial contamination. Nearly 65% of industrial proteases are isolated from marine microbial source, and they can significantly resist a wide range of organic solvents at high temperatures. The most important trait of marine organisms is their adaptability, which allows them to grow optimally in harsh environments such as high salt, temperatures, and pressure-the characteristics of deep-sea hot springs and geothermal sediments...
February 13, 2018: Extremophiles: Life Under Extreme Conditions
Saber Khelaifia, Aurelia Caputo, Claudia Andrieu, Frederique Cadoret, Nicholas Armstrong, Caroline Michelle, Jean-Christophe Lagier, Felix Djossou, Pierre-Edouard Fournier, Didier Raoult
By applying the culturomics concept and using culture conditions containing a high salt concentration, we herein isolated the first known halophilic archaeon colonizing the human gut. Here we described its phenotypic and biochemical characterization as well as its genome annotation. Strain Arc-HrT (= CSUR P0974 = CECT 9307) was mesophile and grew optimally at 37 °C and pH 7. Strain Arc-HrT was also extremely halophilic with an optimal growth observed at 15% NaCl. It showed gram-negative cocci, was strictly aerobic, non-motile and non-spore-forming, and exhibited catalase and oxidase activities...
February 12, 2018: Extremophiles: Life Under Extreme Conditions
Shiping Wei, Hongpeng Cui, Youhai Zhu, Zhenquan Lu, Shouji Pang, Shuai Zhang, Hailiang Dong, Xin Su
Permafrost thaw can bring negative consequences in terms of ecosystems, resulting in permafrost collapse, waterlogging, thermokarst lake development, and species composition changes. Little is known about how permafrost thaw influences microbial community shifts and their activities. Here, we show that the dominant archaeal community shifts from Methanomicrobiales to Methanosarcinales in response to the permafrost thaw, and the increase in methane emission is found to be associated with the methanogenic archaea, which rapidly bloom with nearly tenfold increase in total number...
February 10, 2018: Extremophiles: Life Under Extreme Conditions
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