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Extremophiles: Life Under Extreme Conditions

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https://www.readbyqxmd.com/read/28710671/functional-characterization-of-hormone-sensitive-like-lipase-from-bacillus-halodurans-synthesis-and-recovery-of-pnp-laurate-with-high-yields
#1
Ashima Dua, Rani Gupta
The HSL-like lipase encoding gene (Blip) from the polyextremophile Bacillus halodurans C-125 has been heterologously expressed in E.coli BL21(DE3). The enzyme is a monomer of ~42 kDa. It has extremely high thermal stability with a t 1/2 of 35 min at 100 °C. Thermal denaturation/renaturation studies by CD and fluorescence analysis revealed complete refolding of the protein back to its native conformation even after 30 min at 90 °C. Blip prefers substrates with mid to long chain fatty acids. It has a higher catalytic efficiency on para-nitrophenyl fatty acyl esters as opposed to triacylglycerides (k cat/K m with pNP-palmitate as a substrate was 2...
July 14, 2017: Extremophiles: Life Under Extreme Conditions
https://www.readbyqxmd.com/read/28688056/gene-regulation-of-two-ferredoxin-nadp-oxidoreductases-by-the-redox-responsive-regulator-surr-in-thermococcus-kodakarensis
#2
Ryota Hidese, Keita Yamashita, Kohei Kawazuma, Tamotsu Kanai, Haruyuki Atomi, Tadayuki Imanaka, Shinsuke Fujiwara
The redox-responsive regulator SurR in the hyperthermophilic archaea Pyrococcus furiosus and Thermococcus kodakarensis binds to the SurR-binding consensus sequence (SBS) by responding to the presence of elemental sulfur. Here we constructed a surR gene disruption strain (DTS) in T. kodakarensis, and identified the genes that were under SurR control by comparing the transcriptomes of DTS and parent strains. Among these genes, transcript levels of ferredoxin:NADP(+) oxidoreductases 1 and 2 (FNOR1 and FNOR2) genes displayed opposite responses to surR deletion, indicating that SurR repressed FNOR1 transcription while enhancing FNOR2 transcription...
July 7, 2017: Extremophiles: Life Under Extreme Conditions
https://www.readbyqxmd.com/read/28681113/structure-and-mechanisms-of-viral-transcription-factors-in-archaea
#3
REVIEW
Carol Sheppard, Finn Werner
Virus-encoded transcription factors have been pivotal in exploring the molecular mechanisms and regulation of gene expression in bacteria and eukaryotes since the birth of molecular biology, while our understanding of viral transcription in archaea is still in its infancy. Archaeal viruses do not encode their own RNA polymerases (RNAPs) and are consequently entirely dependent on their hosts for gene expression; this is fundamentally different from many bacteriophages and requires alternative regulatory strategies...
July 5, 2017: Extremophiles: Life Under Extreme Conditions
https://www.readbyqxmd.com/read/28681112/characterization-of-a-cold-active-bacterium-isolated-from-the-south-pole-ice-tunnel
#4
Michael T Madigan, Megan L Kempher, Kelly S Bender, Paul Sullivan, W Matthew Sattley, Alice C Dohnalkova, Samantha B Joye
Extremely cold microbial habitats on Earth (those below -30 °C) are rare and have not been surveyed for microbes as extensively as environments in the 0 to -20 °C range. Using cryoprotected growth media incubated at -5 °C, we enriched a cold-active Pseudomonas species from -50 °C ice collected from a utility tunnel for wastewater pipes under Amundsen-Scott South Pole Station, Antarctica. The isolate, strain UC-1, is related to other cold-active Pseudomonas species, most notably P. psychrophila, and grew at -5 °C to +34-37 °C; growth of UC-1 at +3 °C was significantly faster than at +34 °C...
July 5, 2017: Extremophiles: Life Under Extreme Conditions
https://www.readbyqxmd.com/read/28660362/antarctic-rocks-from-continental-antarctica-as-source-of-potential-human-opportunistic-fungi
#5
Vívian N Gonçalves, Fabio S Oliveira, Camila R Carvalho, Carlos E G R Schaefer, Carlos A Rosa, Luiz H Rosa
We assessed the diversity of culturable fungi associated with rocks of continental Antarctica to evaluate their physiological opportunistic virulence potential in vitro. The seventy fungal isolates obtained were identified as nine species of Acremonium, Byssochlamys, Cladosporium, Debaryomyces, Penicillium, and Rhodotorula. Acremonium sp., D. hansenii, P. chrysogenum, P. citrinum, P. tardochrysogenum, and R. mucilaginosa were able to grow at 37 °C; in addition, B. spectabilis displayed a high level of growth at 37 and 45 °C...
June 28, 2017: Extremophiles: Life Under Extreme Conditions
https://www.readbyqxmd.com/read/28660361/establishment-of-a-markerless-gene-deletion-system-in-chromohalobacter-salexigens-dsm-3043
#6
Ya-Hui Shao, Li-Zhong Guo, Hao Yu, Bai-Suo Zhao, Wei-Dong Lu
Chromohalobacter salexigens DSM 3043 can grow over a wide range of salinity, which makes it as an excellent model organism for understanding the mechanism of prokaryotic osmoregulation. Functional analysis of C. salexigens genes is an essential way to reveal their roles in cellular osmoregulation. However, the lack of an effective markerless gene deletion system has prevented construction of multiple gene deletion mutants for the members in the genus. Here, we report the development of a markerless gene deletion system in C...
June 28, 2017: Extremophiles: Life Under Extreme Conditions
https://www.readbyqxmd.com/read/28597046/molecular-cloning-and-expression-analysis-of-major-intrinsic-protein-gene-in-chlamydomonas-sp-ice-l-from-antarctica
#7
Lulu Li, Meiling An, Changfeng Qu, Zhou Zheng, Yibin Wang, Fangming Liu, Yingying He, Xiaodong He, Jinlai Miao
Major intrinsic proteins (MIPs) form channels facilitating the passive transport of water and other small polar molecules across membranes. In this study, the complete open reading frame (ORF) of CiMIP1 (GenBank ID KY316061) encoding one kind of MIPs in the Antarctic ice microalga Chlamydomonas sp. ICE-L is successfully cloned using RACE. In addition, the expression patterns of CiMIP1 gene under different conditions of temperature and salinity are determined by qRT-PCR. The ORF of CiMIP1 gene encodes 308 amino acids, and the deduced amino acid sequence shows 74% homology with Chlamydomonas reinhardtii CrMIP1 (GenBank number 159471952)...
July 2017: Extremophiles: Life Under Extreme Conditions
https://www.readbyqxmd.com/read/28597045/biocontrol-activity-of-a-cold-adapted-yeast-from-tibet-against-gray-mold-in-cherry-tomato-and-its-action-mechanism
#8
Hao Hu, Michael E Wisniewski, Ahmed Abdelfattah, Xiaodong Zheng
Cold-adapted biocontrol yeast was selected from four yeast isolates from Tibet against gray mold of cherry tomato in cold storage. The strain numbered LB2 showed the best biocontrol activity and identified as Cryptococcus laurentii. Competition for nutrient, space, and induced fruit resistance was also its antagonistic mechanism. Compared with C. laurentii from sea-level place, the reason why LB2 had a better biocontrol activity was studied. More trehalose and proline in cell of LB2 made it exhibit a better cellular activity at low temperature, such as higher population dynamics in the wounds of cherry tomato and more biocontrol-related enzyme secretion, chitinase and β-glucanase...
July 2017: Extremophiles: Life Under Extreme Conditions
https://www.readbyqxmd.com/read/28577249/progeny-production-in-the-periplasm-of-thermosipho-globiformans
#9
Tomohiko Kuwabara, Kensuke Igarashi
Thermotogales are rod-shaped, Gram-negative, anaerobic, (hyper) thermophiles distinguished by an outer sheath-like toga, which comprises an outer membrane (OM) and an amorphous layer (AL). Thermosipho globiformans bacteria can transform into spheroids with multiple cells concurrently with AL disintegration during early growth; the cell is defined as the cytoplasmic membrane (CM) plus the entity surrounded by the CM. Spheroids eventually produce rapidly moving periplasmic 'progenies' through an unknown mechanism...
July 2017: Extremophiles: Life Under Extreme Conditions
https://www.readbyqxmd.com/read/28508135/adaptations-of-archaeal-and-bacterial-membranes-to-variations-in-temperature-ph-and-pressure
#10
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...
July 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
#11
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...
July 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
#12
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...
July 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
#13
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...
July 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
#14
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...
July 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
#15
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...
July 2017: Extremophiles: Life Under Extreme Conditions
https://www.readbyqxmd.com/read/28447265/nadp-dependent-isocitrate-dehydrogenase-from-a-psychrophilic-bacterium-psychromonas-marina
#16
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%)...
July 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
#17
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...
July 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
#18
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...
July 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
#19
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...
July 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
#20
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
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