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Extremophiles: Life Under Extreme Conditions

Fumiaki Yokoyama, Jun Kawamoto, Tomoya Imai, Tatsuo Kurihara
A cold-adapted bacterium, Shewanella livingstonensis Ac10, which produces eicosapentaenoic acid (EPA) as a component of its membrane phospholipids, is useful as a model to study the function of EPA and as a host for heterologous production of thermolabile proteins at low temperatures. In this study, we characterized extracellular membrane vesicles (EMVs) of this bacterium to examine the involvement of EPA in the biogenesis of EMVs and for the future application of EMVs to extracellular protein production. We found that this strain produced EMVs from the cell surface...
April 22, 2017: Extremophiles: Life Under Extreme Conditions
Junpei Zhou, Zhifeng Song, Rui Zhang, Caihong Chen, Qian Wu, Junjun Li, Xianghua Tang, Bo Xu, Junmei Ding, Nanyu Han, Zunxi Huang
β-N-Acetylglucosaminidases (GlcNAcases) are important for many biological functions and industrial applications. In this study, a glycoside hydrolase family 20 GlcNAcase from Shinella sp. JB10 was expressed in Escherichia coli BL21 (DE3). Compared to many GlcNAcases, the purified recombinant enzyme (rJB10Nag) exhibited a higher specificity activity (538.8 µmol min(-1) mg(-1)) or V max (1030.0 ± 82.1 µmol min(-1) mg(-1)) toward p-nitrophenyl β-N-acetylglucosaminide and N,N'-diacetylchitobiose (specificity activity of 35...
April 21, 2017: Extremophiles: Life Under Extreme Conditions
Attila Szabó, Kristóf Korponai, Csaba Kerepesi, Boglárka Somogyi, Lajos Vörös, Dániel Bartha, Károly Márialigeti, Tamás Felföldi
Soda pans of the Pannonian steppe are unique environments regarding their physical and chemical characteristics: shallowness, high turbidity, intermittent character, alkaline pH, polyhumic organic carbon concentration, hypertrophic condition, moderately high salinity, sodium and carbonate ion dominance. The pans are highly productive environments with picophytoplankton predominance. Little is known about the planktonic bacterial communities inhabiting these aquatic habitats; therefore, amplicon sequencing and shotgun metagenomics were applied to reveal their composition and functional properties...
April 7, 2017: Extremophiles: Life Under Extreme Conditions
Alison Besse, Manon Vandervennet, Christophe Goulard, Jean Peduzzi, Stéphanie Isaac, Sylvie Rebuffat, Alyssa Carré-Mlouka
Halophilic archaea thrive in hypersaline ecosystems and produce antimicrobial peptides (AMPs) named halocins. AMPs are essential effectors of microbial interactions in natural ecosystems. Halocin C8 is a 7.4 kDa peptide produced by Natrinema sp. AS7092. Surrounded by genes involved in regulation and transport, the halC8 gene encodes a precursor, processed into the mature halocin and an immunity protein, protecting the producing strain against its halocin. This feature constitutes a unique property of halocin C8, as known AMPs and their immunity proteins are generally encoded on distinct ORFs in an operon...
April 6, 2017: Extremophiles: Life Under Extreme Conditions
Vijay Kumar, Santosh Kumar Tiwari
Haloferax larsenii HA3 was able to grow optimally in HS medium containing 15% NaCl, at pH 7.2 and 42 °C in aerobic conditions. Strain HA3 was found to be round shape, Gram-negative, catalase-positive, sensitive to bile acid, and resistant to chloramphenicol, and could not utilize arginine. The lipid profile revealed the presence of glycerol diether moiety (GDEM) suggesting Haloarchaea characteristics. Phylogenetic analysis based on 16S rRNA gene sequence similarities showed that it was closely related to H...
April 4, 2017: Extremophiles: Life Under Extreme Conditions
Yurina Miyashita, Eiji Ohmae, Teikichi Ikura, Kaoru Nakasone, Katsuo Katayanagi
Dihydrofolate (DHF) reductase coded by a plasmid of the extremely halophilic archaeon Haloarcula japonica strain TR-1 (HjDHFR P1) shows moderate halophilicity on enzymatic activity at pH 6.0, although there is no significant effect of NaCl on its secondary structure. To elucidate the salt-activation and -inactivation mechanisms of this enzyme, we investigated the effects of pH and salt concentration, deuterium isotope effect, steady-state kinetics, and rapid-phase ligand-binding kinetics. Enzyme activity was increased eightfold by the addition of 500 mM NaCl at pH 6...
March 27, 2017: Extremophiles: Life Under Extreme Conditions
Gina L Lipscomb, Elin M Hahn, Alexander T Crowley, Michael W W Adams
Reverse gyrase is an enzyme that induces positive supercoiling in closed circular DNA in vitro. It is unique to thermophilic organisms and found without exception in all microorganisms defined as hyperthermophiles, that is, those having optimal growth temperatures of 80 °C and above. Although its in vivo role has not been clearly defined, it has been implicated in stabilizing DNA at high temperatures. Whether or not it is absolutely required for growth at these high temperatures has yet to be fully determined...
March 22, 2017: Extremophiles: Life Under Extreme Conditions
Ye Zhou, Guiqiu Xie, Lin Chang, Yan Wang, Renjun Gao
Complete genome analysis of the thermoacidophilic Archaeon Sulfolobus tokodaii strain 7 revealed two open reading frames (ORF), namely, ST0926 and ST0927. These ORFs are interrupted by two putative insertions and encode for the N- and C-terminal fragments, respectively, of a putative Sulfolobus sp. maltooligosyltrehalose trehalohydrolase (StMTHase). Two specific deletion mutations, designed on the basis of sequence alignments of the adjacent ORFs and the published Sulfolobus sp. MTHases, allowed soluble expression in Escherichia coli of an active acidic and thermophilic enzyme...
March 21, 2017: Extremophiles: Life Under Extreme Conditions
Volkan Kilic, Gözde Aydoğan Kilic, Hatice Mehtap Kutlu, Rosa María Martínez-Espinosa
Haloferax alexandrinus Strain TM JCM 10717(T) = IFO 16590(T) is an extreme halophilic archaeon able to produce significant amounts of canthaxanthin. Its genome sequence has been analysed in this work using bioinformatics tools available at Expasy in order to look for genes encoding nitrate reductase-like proteins: respiratory nitrate reductase (Nar) and/or assimilatory nitrate reductase (Nas). The ability of the cells to reduce nitrate under aerobic conditions was tested. The enzyme in charge of nitrate reduction under aerobic conditions (Nas) has been purified and characterised...
March 21, 2017: Extremophiles: Life Under Extreme Conditions
S K Schmidt, J L Darcy, Pacifica Sommers, Eva Gunawan, J E Knelman, Karina Yager
This is the first study of the highest elevation cyanobacteria-dominated microbial mat yet described. The desiccated mat was sampled in 2010 from an ephemeral rock pool at 5500 m above sea level in the Cordillera Vilcanota of southern Perú. After being frozen for 6 years at -20 °C in the lab, pieces of the mat were sequenced to fully characterize both the 16 and 18S microbial communities and experiments were conducted to determine if organisms in the mat could revive and become active under the extreme freeze-thaw conditions that these mats experience in the field...
March 21, 2017: Extremophiles: Life Under Extreme Conditions
Ravinder Kumar, Anil Kumar Pinnaka, Beena Krishnan
A moderately thermophilic Gram-negative bacterium isolated from the Polok hot spring, Sikkim, India, was identified as a strain (PL17) of Tepidimonas fonticaldi by 16S rDNA sequencing. T. fonticaldi PL17 produces a Type IIP restriction endonuclease; named TfoI. Restriction mapping, run-off sequencing of TfoI-digests of dsDNA fragments, and end compatibility of TfoI with NdeI confirmed that the enzyme recognizes and cleaves the sequence 5'-T^TAA-3', and is thus an isoschizomer of MseI. The TfoI restriction-modification genes in the T...
March 18, 2017: Extremophiles: Life Under Extreme Conditions
Saadia Basheer, Naeem Rashid, Raza Ashraf, Muhammad Sohail Akram, Masood Ahmed Siddiqui, Tadayuki Imanaka, Muhammad Akhtar
Genome search of Geobacillus thermopakistaniensis, formerly Geobacillus sp. SBS-4S, revealed the presence of an open reading frame (ESU71923) annotated as laccase. However, the gene product did not display any laccase-like activity against the substrates examined. The laccase activity was, therefore, purified from G. thermopakistaniensis cells and N-terminal amino acid residues of the enzyme were determined. These residues matched the N-terminal sequence of an open reading frame annotated as a copper oxidase (ESU72270)...
March 17, 2017: Extremophiles: Life Under Extreme Conditions
Shan Zhang, Weizhi Song, Min Yu, Xuezheng Lin
Psychrobacter has been regarded as an important genus for bacterial cold adaptation studies. However, members of this genus are highly varied in terms of both cold adaptability and genome content. To get an understanding of the diversity of members of this genus, five Psychrobacter strains (G, K5, 273-4, PAMC21119 and PRwf-1), with publicly available complete/draft genome, were selected and comprehensive comparative genomics analyses were performed among them. The closest phylogenetic relationship, highest average nucleotide identity (96...
March 17, 2017: Extremophiles: Life Under Extreme Conditions
Iram Aziz, Naeem Rashid, Raza Ashraf, Qamar Bashir, Tadayuki Imanaka, Muhammad Akhtar
Pyrobaculum calidifontis genome harbors an open reading frame Pcal_0111 annotated as fructose bisphosphate aldolase. Although the gene is annotated as fructose bisphosphate aldolase, it exhibits a high homology with previously reported fructose-1,6-bisphosphate aldolase/phosphatase from Thermoproteus neutrophilus. To examine the biochemical properties of Pcal_0111, we have cloned and expressed the gene in Escherichia coli. Purified recombinant Pcal_0111 catalyzed both phosphatase and aldolase reactions with specific activity values of 4 U and 1...
March 15, 2017: Extremophiles: Life Under Extreme Conditions
Miguel Medrano-Santillana, Elcia Margaret Souza-Brito, Robert Duran, Felix Gutierrez-Corona, Georgina Elena Reyna-López
Active volcanoes are among the most extreme environments on Earth. The extreme temperatures, presence of toxic heavy metals and low nutrient bioavailability favor the development of extremophiles. We characterized the physical-chemical parameters of and bacterial communities (T-RFLP and 16S rRNA gene libraries) inhabiting fumarole niches of the Paricutín volcano located in Michoacán (Mexico). This volcano, which surged in 1943, is one of the youngest volcanoes on Earth and the microbial diversity in this area is yet to be characterized...
March 13, 2017: Extremophiles: Life Under Extreme Conditions
Debamitra Chakravorty, Mohd Faheem Khan, Sanjukta Patra
Research on extremostable proteins has seen immense growth in the past decade owing to their industrial importance. Basic research of attributes related to extreme-stability requires further exploration. Modern mechanistic approaches to engineer such proteins in vitro will have more impact in industrial biotechnology economy. Developing a priori knowledge about the mechanism behind extreme-stability will nurture better understanding of pathways leading to protein molecular evolution and folding. This review is a vivid compilation about all classes of extremostable proteins and the attributes that lead to myriad of adaptations divulged after an extensive study of 6495 articles belonging to extremostable proteins...
March 10, 2017: Extremophiles: Life Under Extreme Conditions
Pablo Marcelo Fernández, María Martha Martorell, Mariana G Blaser, Lucas Adolfo Mauro Ruberto, Lucía Inés Castellanos de Figueroa, Walter Patricio Mac Cormack
In cold environments, biodegradation of organic pollutants and heavy metal bio-conversion requires the activity of cold-adapted or cold-tolerant microorganisms. In this work, the ability to utilize phenol, methanol and n-hexadecane as C source, the tolerance to different heavy metals and growth from 5 to 30 °C were evaluated in cold-adapted yeasts isolated from Antarctica. Fifty-nine percent of the yeasts were classified as psychrotolerant as they could grow in all the range of temperature tested, while the other 41% were classified as psychrophilic as they only grew below 25 °C...
March 7, 2017: Extremophiles: Life Under Extreme Conditions
Amrik Bhattacharya, Nidhi Goyal, Anshu Gupta
Effluents from textile industries are highly colored due to vast use of various azo dyes and color is the first visual indicator of pollution. Biological treatment of textile effluent is often hampered due to the alkaline pH and high salinity; a common characteristic of many textile industrial wastewaters. Considering this, the present study explores the potential of a newly isolated halotolerant and alkaliphilic bacterium Nesterenkonia lacusekhoensis EMLA3 for degradation of methyl red (MR) dye under alkaline condition...
March 2, 2017: Extremophiles: Life Under Extreme Conditions
Jae Kyu Lim, Hae-Chang Jung, Sung Gyun Kang, Hyun Sook Lee
Protein disulfide oxidoreductases are redox enzymes that catalyze thiol-disulfide exchange reactions. These enzymes include thioredoxins, glutaredoxins, protein disulfide isomerases, disulfide bond formation A (DsbA) proteins, and Pyrococcus furiosus protein disulfide oxidoreductase (PfPDO) homologues. In the genome of a hyperthermophilic archaeon, Thermococcus onnurineus NA1, the genes encoding one PfPDO homologue (TON_0319, Pdo) and three more thioredoxin- or glutaredoxin-like proteins (TON_0470, TON_0472, TON_0834) were identified...
March 1, 2017: Extremophiles: Life Under Extreme Conditions
Carmen Falagán, Bärbel Foesel, Barrie Johnson
Four novel strains of Acidobacteria were isolated from water samples taken from pit lakes at two abandoned metal mines in the Iberian Pyrite Belt mining district, south-west Spain. Three of the isolates belong to the genus Acidicapsa (MCF9(T), MCF10(T), and MCF14) and one of them to the genus Granulicella (MCF40(T)). All isolates are moderately acidophilic (pH growth optimum 3.8-4.1) and mesophilic (temperature growth optima 30-32 °C). Isolates MCF10(T) and MCF40(T) grew at pH lower (<3.0) than previously reported for all other acidobacteria...
February 22, 2017: Extremophiles: Life Under Extreme Conditions
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