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Extremophiles: Life Under Extreme Conditions

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https://www.readbyqxmd.com/read/28508135/adaptations-of-archaeal-and-bacterial-membranes-to-variations-in-temperature-ph-and-pressure
#1
REVIEW
Melvin F Siliakus, John van der Oost, Servé W M Kengen
The cytoplasmic membrane of a prokaryotic cell consists of a lipid bilayer or a monolayer that shields the cellular content from the environment. In addition, the membrane contains proteins that are responsible for transport of proteins and metabolites as well as for signalling and energy transduction. Maintenance of the functionality of the membrane during changing environmental conditions relies on the cell's potential to rapidly adjust the lipid composition of its membrane. Despite the fundamental chemical differences between bacterial ester lipids and archaeal ether lipids, both types are functional under a wide range of environmental conditions...
May 15, 2017: Extremophiles: Life Under Extreme Conditions
https://www.readbyqxmd.com/read/28500388/aspergillus-atacamensis-and-a-salisburgensis-two-new-halophilic-species-from-hypersaline-arid-habitats-with-a-phialosimplex-like-morphology
#2
Livia Martinelli, Polona Zalar, Nina Gunde-Cimerman, Armando Azua-Bustos, Katja Sterflinger, Guadalupe Piñar
Halophilic fungal strains isolated from historical wooden staircase in a salt mine in Austria, and from wall biofilm and soil of a cave in the Coastal Range of the hyperarid Atacama Desert in Chile were characterised and described newly as Aspergillus salisburgensis and Aspergillus atacamensis. Morphological characters including solitary phialides producing solitary conidia and conidia in chains and/or heads suggested affinity to Aspergillus subgenus Polypaecilum. Strains required salt for growth, grew optimally on media with 10-25% NaCl and at 15-28 °C...
May 12, 2017: Extremophiles: Life Under Extreme Conditions
https://www.readbyqxmd.com/read/28500387/thermal-adaptation-strategies-of-the-extremophile-bacterium-thermus-filiformis-based-on-multi-omics-analysis
#3
F Mandelli, M B Couger, D A A Paixão, C B Machado, C M Carnielli, J A Aricetti, I Polikarpov, R Prade, C Caldana, A F Paes Leme, A Z Mercadante, D M Riaño-Pachón, Fabio Marcio Squina
Thermus filiformis is an aerobic thermophilic bacterium isolated from a hot spring in New Zealand. The experimental study of the mechanisms of thermal adaptation is important to unveil response strategies of the microorganism to stress. In this study, the main pathways involved on T. filiformis thermoadaptation, as well as, thermozymes with potential biotechnological applications were revealed based on omics approaches. The strategy adopted in this study disclosed that pathways related to the carbohydrate metabolism were affected in response to thermoadaptation...
May 12, 2017: Extremophiles: Life Under Extreme Conditions
https://www.readbyqxmd.com/read/28493148/diversity-of-bacteria-and-archaea-from-two-shallow-marine-hydrothermal-vents-from-vulcano-island
#4
Garabed Antranikian, Marcel Suleiman, Christian Schäfers, Michael W W Adams, Simonetta Bartolucci, Jenny M Blamey, Nils-Kåre Birkeland, Elizaveta Bonch-Osmolovskaya, Milton S da Costa, Don Cowan, Michael Danson, Patrick Forterre, Robert Kelly, Yoshizumi Ishino, Jennifer Littlechild, Marco Moracci, Kenneth Noll, Tairo Oshima, Frank Robb, Mosè Rossi, Helena Santos, Peter Schönheit, Reinhard Sterner, Rudolf Thauer, Michael Thomm, Jürgen Wiegel, Karl Otto Stetter
To obtain new insights into community compositions of hyperthermophilic microorganisms, defined as having optimal growth temperatures of 80 °C and above, sediment and water samples were taken from two shallow marine hydrothermal vents (I and II) with temperatures of 100 °C at Vulcano Island, Italy. A combinatorial approach of denaturant gradient gel electrophoresis (DGGE) and metagenomic sequencing was used for microbial community analyses of the samples. In addition, enrichment cultures, growing anaerobically on selected polysaccharides such as starch and cellulose, were also analyzed by the combinatorial approach...
May 10, 2017: Extremophiles: Life Under Extreme Conditions
https://www.readbyqxmd.com/read/28478604/membrane-lipids-and-soluble-sugars-dynamics-of-the-alkaliphilic-fungus-sodiomyces-tronii-in-response-to-ambient-ph
#5
Sofiya A Bondarenko, Elena A Ianutsevich, Olga A Danilova, Alexey A Grum-Grzhimaylo, Ekaterina R Kotlova, Olga V Kamzolkina, Elena N Bilanenko, Vera M Tereshina
Alkaliphily, the ability of an organism to thrive optimally at high ambient pH, has been well-documented in several lineages: archaea, bacteria and fungi. The molecular mechanics of such adaptation has been extensively addressed in alkaliphilic bacteria and alkalitolerant fungi. In this study, we consider an additional property that may have enabled fungi to prosper at alkaline pH: altered contents of membrane lipids and cytoprotectant molecules. In the alkaliphilic Sodiomyces tronii, we showed that at its optimal growth pH 9...
May 6, 2017: Extremophiles: Life Under Extreme Conditions
https://www.readbyqxmd.com/read/28447266/in-depth-characterization-of-bacterial-and-archaeal-communities-present-in-the-abandoned-kettara-pyrrhotite-mine-tailings-morocco
#6
Odile Bruneel, N Mghazli, R Hakkou, I Dahmani, A Filali Maltouf, L Sbabou
In Morocco, pollution caused by closed mines continues to be a serious threat to the environment, like the generation of acid mine drainage. Mine drainage is produced by environmental and microbial oxidation of sulfur minerals originating from mine wastes. The fundamental role of microbial communities is well known, like implication of Fe-oxidizing and to a lesser extent S-oxidizing microorganism in bioleaching. However, the structure of the microbial communities varies a lot from one site to another, like diversity depends on many factors such as mineralogy, concentration of metals and metalloids or pH, etc...
April 26, 2017: Extremophiles: Life Under Extreme Conditions
https://www.readbyqxmd.com/read/28447265/nadp-dependent-isocitrate-dehydrogenase-from-a-psychrophilic-bacterium-psychromonas-marina
#7
Ryo Hirota, Kango Tsubouchi, Yasuhiro Takada
The gene encoding NADP(+)-dependent isocitrate dehydrogenase (IDH; EC 1.1.1.42) of a psychrophilic bacterium, Psychromonas marina, was cloned and sequenced. The open reading frame of the gene encoding IDH of P. marina (PmIDH) was 2229 bp in length and corresponded to a polypeptide composed of 742 amino acids. The molecular mass of IDH was calculated as 80,426 Da. The deduced amino acid sequence of PmIDH exhibited high degrees of homology with the monomeric IDH from other bacteria such as Colwellia maris (62% identity) and Azotobacter vinelandii (AvIDH) (64%)...
April 26, 2017: Extremophiles: Life Under Extreme Conditions
https://www.readbyqxmd.com/read/28444450/sgnh-hydrolase-type-esterase-domain-containing-cbes-acxe2-a-novel-and-thermostable-acetyl-xylan-esterase-from-caldicellulosiruptor-bescii
#8
Surabhi Soni, Sneha S Sathe, Annamma A Odaneth, Arvind M Lali, Sanjeev K Chandrayan
Caldicellulosiruptor bescii, the most thermophilic cellulolytic bacterium, is rich in hydrolytic and accessory enzymes that can degrade untreated biomass, but the precise role of many these enzymes is unknown. One of such enzymes is a predicted GDSL lipase or esterase encoded by the locus Athe_0553. In this study, this probable esterase named as Cbes-AcXE2 was overexpressed in Escherichia coli. The Ni-NTA affinity purified enzyme exhibited an optimum pH of 7.5 at an optimum temperature of 70 °C. Cbes-AcXE2 hydrolyzed p-nitrophenyl (pNP) acetate, pNP-butyrate, and phenyl acetate with approximately equal efficiency...
April 25, 2017: Extremophiles: Life Under Extreme Conditions
https://www.readbyqxmd.com/read/28434130/characterization-of-extracellular-membrane-vesicles-of-an-antarctic-bacterium-shewanella-livingstonensis-ac10-and-their-enhanced-production-by-alteration-of-phospholipid-composition
#9
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
https://www.readbyqxmd.com/read/28432475/a-shinella-%C3%AE-n-acetylglucosaminidase-of-glycoside-hydrolase-family-20-displays-novel-biochemical-and-molecular-characteristics
#10
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
https://www.readbyqxmd.com/read/28389755/soda-pans-of-the-pannonian-steppe-harbor-unique-bacterial-communities-adapted-to-multiple-extreme-conditions
#11
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
https://www.readbyqxmd.com/read/28386790/halocin-c8-an-antimicrobial-peptide-distributed-among-four-halophilic-archaeal-genera-natrinema-haloterrigena-haloferax-and-halobacterium
#12
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
https://www.readbyqxmd.com/read/28378299/activity-guided-separation-and-characterization-of-new-halocin-ha3-from-fermented-broth-of-haloferax-larsenii-ha3
#13
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
https://www.readbyqxmd.com/read/28349498/halophilic-mechanism-of-the-enzymatic-function-of-a-moderately-halophilic-dihydrofolate-reductase-from-haloarcula-japonica-strain-tr-1
#14
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
https://www.readbyqxmd.com/read/28331998/reverse-gyrase-is-essential-for-microbial-growth-at-95%C3%A2-%C3%A2-c
#15
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
https://www.readbyqxmd.com/read/28321616/identification-of-an-archaeal-maltooligosyltrehalose-trehalohydrolase-encoded-by-an-interrupted-gene
#16
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
https://www.readbyqxmd.com/read/28321615/nitrate-reduction-in-haloferax-alexandrinus-the-case-of-assimilatory-nitrate-reductase
#17
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
https://www.readbyqxmd.com/read/28321614/freeze-thaw-revival-of-rotifers-and-algae-in-a-desiccated-high-elevation-5500-meters-microbial-mat-high-andes-per%C3%A3%C2%BA
#18
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
https://www.readbyqxmd.com/read/28315976/tfoi-produced-by-tepidimonas-fonticaldi-pl17-a-moderate-thermophilic-bacterium-is-an-isoschizomer-of-msei
#19
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
https://www.readbyqxmd.com/read/28314922/identification-of-a-novel-copper-activated-and-halide-tolerant-laccase-in-geobacillus-thermopakistaniensis
#20
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
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