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https://www.readbyqxmd.com/read/28633515/crystal-structure-and-functional-characterization-of-a-cytochrome-p450-bacyp106a2-from-bacillus-sp-pamc-23377
#1
Ki-Hwa Kim, Chang Woo Lee, Bikash Dangi, Sun-Ha Park, Hyun Park, Tae-Jin Oh, Jun Hyuck Lee
Bacterial cytochrome P450 (CYP) steroid hydroxylases are effectively useful in the pharmaceutical industry for introducing hydroxyl groups to a wide range of steroids. We found a putative CYP steroid hydroxylase (BaCYP106A2) from the bacterium Bacillus sp. PAMC 23377 isolated from Kara Sea of the Arctic Ocean, showing 94% sequence similarity with BmCYP106A2 (Bacillus megaterium ATCC 13368). In this study, soluble BaCYP106A2 was overexpressed to evaluate its substrate-binding activity. The substrate affinity (Kd value) to 4-androstenedione was 387 ± 37 µM...
June 21, 2017: Journal of Microbiology and Biotechnology
https://www.readbyqxmd.com/read/28586678/polar-oceans-in-a-changing-climate
#2
David K A Barnes, Geraint A Tarling
Most of Earth's surface is blue or white, but how much of each would depend on the time of observation. Our planet has been through phases of snowball (all frozen), greenhouse (all liquid seas) and icehouse (frozen and liquid). Even during current icehouse conditions, the extent of ice versus water has changed considerably between ice ages and interglacial periods. Water has been vital for life on Earth and has driven and been influenced by transitions between greenhouse and icehouse. However, neither the possession of water nor having liquid and frozen seas are unique to Earth (Figure 1)...
June 5, 2017: Current Biology: CB
https://www.readbyqxmd.com/read/28500441/route-simulations-compass-mechanisms-and-long-distance-migration-flights-in-birds
#3
REVIEW
Susanne Åkesson, Giuseppe Bianco
Bird migration has fascinated humans for centuries and routes crossing the globe are now starting to be revealed by advanced tracking technology. A central question is what compass mechanism, celestial or geomagnetic, is activated during these long flights. Different approaches based on the geometry of flight routes across the globe and route simulations based on predictions from compass mechanisms with or without including the effect of winds have been used to try to answer this question with varying results...
May 12, 2017: Journal of Comparative Physiology. A, Neuroethology, Sensory, Neural, and Behavioral Physiology
https://www.readbyqxmd.com/read/28358884/nitrogen-balance-along-a-northern-boreal-forest-fire-chronosequence
#4
Marjo Palviainen, Jukka Pumpanen, Frank Berninger, Kaisa Ritala, Baoli Duan, Jussi Heinonsalo, Hui Sun, Egle Köster, Kajar Köster
Fire is a major natural disturbance factor in boreal forests, and the frequency of forest fires is predicted to increase due to climate change. Nitrogen (N) is a key determinant of carbon sequestration in boreal forests because the shortage of N limits tree growth. We studied changes in N pools and fluxes, and the overall N balance across a 155-year non stand-replacing fire chronosequence in sub-arctic Pinus sylvestris forests in Finland. Two years after the fire, total ecosystem N pool was 622 kg ha-1 of which 16% was in the vegetation, 8% in the dead biomass and 76% in the soil...
2017: PloS One
https://www.readbyqxmd.com/read/28254059/sources-and-distribution-of-sedimentary-organic-matter-along-the-northern-bering-and-chukchi-seas
#5
Fanglu Xu, Haiyan Jin, Zhongqiang Ji, Jianfang Chen, Pei Sun Loh
In this study, lignin-derived phenols were used to determine the sources and distribution of sedimentary organic matter along the northern Bering Sea and Chukchi Sea of the Arctic Ocean. The lignin parameter syringyl/vanillyl (S/V) and cinnamyl/vanillyl (C/V) ratios are used to indicate vegetation sources; and the ratios of vanillic acid/vanillin, (Ad/Al)v and syringic acid/syringaldehyde, (Ad/Al)s are used as indicators of lignin diagenesis. Results showed the predominance of woody gymnosperm signal at the easternmost location in the northern Bering Sea, a mixture of refractory non-woody angiosperm and fresher gymnosperm tissues in the Chukchi Sea, and signal of fresher woody gymnosperm tissues in the northernmost locations in the Chukchi Sea...
February 2017: Journal of Environmental Sciences (China)
https://www.readbyqxmd.com/read/27960070/comparison-of-two-surface-cooling-devices-for-temperature-management-in-a-neurocritical-care-unit
#6
Gurpreet Singh Aujla, Premkumar Nattanmai, Keerthivaas Premkumar, Christopher R Newey
Fever increases mortality and morbidity and length of stay in neurocritically ill patients. Various methods are used in the neuroscience intensive care unit (NSICU) to control fever. Two such methods involve the Arctic Sun hydrogel wraps and the Gaymar cooling wraps. The purpose of our study was to compare these two methods in neurocritical care patients who had temperature >37.5°C for more than three consecutive hours and that was refractory to standard treatments. Data of patients requiring cooling wraps for treatment of hyperthermia at an NSICU at an academic, tertiary referral center were retrospectively reviewed...
December 13, 2016: Therapeutic Hypothermia and Temperature Management
https://www.readbyqxmd.com/read/27611727/untargeted-screening-and-distribution-of-organo-iodine-compounds-in-sediments-from-lake-michigan-and-the-arctic-ocean
#7
Hui Peng, Chunli Chen, Jenna Cantin, David M V Saunders, Jianxian Sun, Song Tang, Garry Codling, Markus Hecker, Steve Wiseman, Paul D Jones, An Li, Karl J Rockne, Neil C Sturchio, Minghong Cai, John P Giesy
The majority of halogenated organic compounds present in the environment remain unidentified. To address this data gap, we recently developed an untargeted method (data-independent precursor isolation and characteristic fragment; DIPIC-Frag) for identification of unknown organo-bromine compounds. In this study, the method was adapted to enable untargeted screening of natural and synthetic organo-iodine compounds (NSOICs) in sediments. A total of 4,238 NSOIC peaks were detected in sediments from Lake Michigan...
September 20, 2016: Environmental Science & Technology
https://www.readbyqxmd.com/read/27577847/in-the-darkness-of-the-polar-night-scallops-keep-on-a-steady-rhythm
#8
Damien Tran, Mohamedou Sow, Lionel Camus, Pierre Ciret, Jorgen Berge, Jean-Charles Massabuau
Although the prevailing paradigm has held that the polar night is a period of biological quiescence, recent studies have detected noticeable activity levels in marine organisms. In this study, we investigated the circadian rhythm of the scallop Chlamys islandica by continuously recording the animal's behaviour over 3 years in the Arctic (Svalbard). Our results showed that a circadian rhythm persists throughout the polar night and lasts for at least 4 months. Based on observations across three polar nights, we showed that the robustness and synchronicity of the rhythm depends on the angle of the sun below the horizon...
2016: Scientific Reports
https://www.readbyqxmd.com/read/27409713/sterols-and-stanols-preserved-in-pond-sediments-track-seabird-biovectors-in-a-high-arctic-environment
#9
Wenhan Cheng, Liguang Sun, Linda E Kimpe, Mark L Mallory, John P Smol, Lauren R Gallant, Jinping Li, Jules M Blais
Seabirds are major vertebrates in the coastal ecosystems of the Canadian High Arctic, where they transport substantial amounts of marine-derived nutrients and pollutants from oceans to land by depositing guano and stomach oils to their nesting area, which often includes nearby freshwater ponds. Here we present novel indicators for evaluating the impact of seabirds on freshwater ecosystems. The ratio of cholesterol/(cholesterol + sitosterol) in pond sediments showed significant enrichment near a nesting colony of northern fulmars (Fulmarus glacialis) and was significantly correlated with ornithogenic enrichment of sediment as determined by sedimentary δ(15)N...
September 6, 2016: Environmental Science & Technology
https://www.readbyqxmd.com/read/27193900/spectral-determination-of-concentrations-of-functionally-diverse-pigments-in-increasingly-complex-arctic-tundra-canopies
#10
Natalie T Boelman, Troy S Magney, Barry A Logan, Kevin L Griffin, Jan U H Eitel, Heather Greaves, Case M Prager, Lee A Vierling
As the Arctic warms, tundra vegetation is becoming taller and more structurally complex, as tall deciduous shrubs become increasingly dominant. Emerging studies reveal that shrubs exhibit photosynthetic resource partitioning, akin to forests, that may need accounting for in the "big leaf" net ecosystem exchange models. We conducted a lab experiment on sun and shade leaves from S. pulchra shrubs to determine the influence of both constitutive (slowly changing bulk carotenoid and chlorophyll pools) and facultative (rapidly changing xanthophyll cycle) pigment pools on a suite of spectral vegetation indices, to devise a rapid means of estimating within canopy resource partitioning...
September 2016: Oecologia
https://www.readbyqxmd.com/read/27103673/adaptations-to-polar-life-in-mammals-and-birds
#11
REVIEW
Arnoldus Schytte Blix
This Review presents a broad overview of adaptations of truly Arctic and Antarctic mammals and birds to the challenges of polar life. The polar environment may be characterized by grisly cold, scarcity of food and darkness in winter, and lush conditions and continuous light in summer. Resident animals cope with these changes by behavioural, physical and physiological means. These include responses aimed at reducing exposure, such as 'balling up', huddling and shelter building; seasonal changes in insulation by fur, plumage and blubber; and circulatory adjustments aimed at preservation of core temperature, to which end the periphery and extremities are cooled to increase insulation...
April 15, 2016: Journal of Experimental Biology
https://www.readbyqxmd.com/read/27049757/towards-a-better-understanding-of-the-effects-of-uv-on-atlantic-walruses-odobenus-rosmarus-rosmarus-a-study-combining-histological-data-with-local-ecological-knowledge
#12
Laura M Martinez-Levasseur, Chris M Furgal, Mike O Hammill, Gary Burness
Walruses, Odobenus rosmarus, play a key role in the Arctic ecosystem, including northern Indigenous communities, which are reliant upon walruses for aspects of their diet and culture. However, walruses face varied environmental threats including rising sea-water temperatures and decreasing ice cover. An underappreciated threat may be the large amount of solar ultraviolet radiation (UV) that continues to reach the Arctic as a result of ozone loss. UV has been shown to negatively affect whales. Like whales, walrus skin is unprotected by fur, but in contrast, walruses spend long periods of time hauled-out on land...
2016: PloS One
https://www.readbyqxmd.com/read/26988644/production-rate-estimation-of-mycosporine-like-amino-acids-in-two-arctic-melt-ponds-by-stable-isotope-probing-with-nah-13-co3
#13
Sun-Yong Ha, Jun-Oh Min, Hyun Min Joo, Kyung Ho Chung, Kyung-Hoon Shin, EunJin Yang, Sung-Ho Kang
The net carbon uptake rate and net production rate of mycosporine-like amino acids (MAAs) were measured in phytoplankton from 2 different melt ponds (MPs; closed and open type pond) in the western Arctic Ocean using a (13) C stable isotope tracer technique. The Research Vessel Araon visited ice-covered western-central basins situated at 82°N and 173°E in the summer of 2012, when Arctic sea ice declined to a record minimum. The average net carbon uptake rate of the phytoplankton in polycarbonate (PC) bottles in the closed MP was 3...
October 2014: Journal of Phycology
https://www.readbyqxmd.com/read/26909958/identification-of-polymorphisms-and-transcriptional-activity-of-the-proto-oncogene-kit-located-on-both-autosomal-and-b-chromosomes-of-the-chinese-raccoon-dog
#14
Y M Li, Y Zhang, W J Zhu, S Q Yan, J H Sun
B chromosomes are dispensable and co-exist with autosomal and sex chromosomes. The karyotype of the Chinese raccoon dog (Nyctereutes procyonoides procyonoides) comprises 0-4 B chromosomes. The proto-oncogene KIT is found on all B chromosomes of the Chinese raccoon dog. In the present study, partial DNA and mRNA sequences of KIT were amplified and sequenced from four individuals containing B chromosomes. Sequence analyses revealed that polymorphisms including single nucleotide polymorphisms (SNPs) and inserts/deletions were rich in the KIT gene of Chinese raccoon dog at the genomic level...
February 5, 2016: Genetics and Molecular Research: GMR
https://www.readbyqxmd.com/read/26899736/interannual-variability-of-average-minimum-temperatures-derived-from-tree-rings-in-the-mid-qinling-mountains-china-for-the-past-138%C3%A2-years
#15
Ying Lei, Yu Liu, Bo Sun, Changfeng Sun
In this study, spruce tree rings from the southern slope of mid-Qinling Mountains were adopted to investigate the characteristics of average minimum temperatures during the past 138 years. Analysis showed that the interannual variability in radial growth of trees was positively correlated with the interannual variability of average minimum temperatures from previous December to current September (VTM DS) in the study area during 1955-2010 AD. Based on the correlation analysis, the VTM DS were reconstructed for 1876-2013 AD with an explained variance of 42...
October 2016: International Journal of Biometeorology
https://www.readbyqxmd.com/read/26855900/prognostic-factors-associated-with-hospital-survival-in-comatose-survivors-of-cardiac-arrest
#16
Kushaharan Sathianathan, Ravindranath Tiruvoipati, Sanjiv Vij
AIM: To identify patient, cardiac arrest and management factors associated with hospital survival in comatose survivors of cardiac arrest. METHODS: A retrospective, single centre study of comatose patients admitted to our intensive care unit (ICU) following cardiac arrest during the twenty year period between 1993 and 2012. This study was deemed by the Human Research Ethics Committee (HREC) of Monash Health to be a quality assurance exercise, and thus did not require submission to the Monash Health HREC (Research Project Application, No...
February 4, 2016: World Journal of Critical Care Medicine
https://www.readbyqxmd.com/read/26688201/characterization-and-biotechnological-potential-analysis-of-a-new-exopolysaccharide-from-the-arctic-marine-bacterium-polaribacter-sp-sm1127
#17
Mei-Ling Sun, Fang Zhao, Mei Shi, Xi-Ying Zhang, Bai-Cheng Zhou, Yu-Zhong Zhang, Xiu-Lan Chen
Although many kinds of exopolysaccharides (EPSs) from microorganisms have been used in industry, the exploration and utilization of EPSs from polar microorganisms is still rather rare. In this study, a flavobacterial strain, SM1127, from the Arctic brown alga Laminaria, was screened for its high EPS production (2.11 g/l) and was identified as belonging to the genus Polaribacter. The EPS secreted by strain SM1127 has a molecular mass of 220 kDa, and it mainly comprises N-acetyl glucosamine, mannose and glucuronic acid residues bound by heterogeneous linkages...
December 21, 2015: Scientific Reports
https://www.readbyqxmd.com/read/26684525/first-report-of-toxoplasma-gondii-seroprevalence-in-farmed-arctic-foxes-vulpes-lagopus-in-eastern-and-northeastern-china
#18
Zhi-Long Lou, Wei Cong, Qing-Feng Meng, Wu-Wen Sun, Si-Yuan Qin, Xiao-Xuan Zhang, Xing-Quan Zhu, Ai-Dong Qian
Until now, no information on Toxoplasma gondii seroprevalence in Arctic foxes (Vulpes lagopus) was available in China. A serological survey was undertaken to assess T. gondii seroprevalence in farmed Arctic foxes in eastern and northeastern China. Antibodies to T. gondii were examined in 1346 farmed Arctic foxes using the modified agglutination test (MAT). A total of 113 (8.39%, 95% confidence interval [CI] 6.91-9.87) serum samples were positive to T. gondii at a 1:25 cutoff. Seroprevalence of T. gondii infection in male Arctic foxes was 8...
December 2015: Vector Borne and Zoonotic Diseases
https://www.readbyqxmd.com/read/26638966/stimulatory-effect-of-ethanol-on-libertellenone-h-biosynthesis-by-arctic-fungus-eutypella-sp-d-1
#19
Chu Shen, Ning Xu, Yanyun Gao, Xiaoyue Sun, Ying Yin, Menghao Cai, Xiangshan Zhou, Yuanxing Zhang
Libertellenone H (1) was a promising antitumor diterpenoid isolated from Arctic fungus Eutypella sp. D-1, however, its production was very limited. In this study, we investigated the effects of ethanol on cell growth and libertellenone H production. The mycelium in ethanol-feeding cultures was fragmented and dispersed, and the titer of libertellenone H was remarkably increased to 4.88 mg l(-1) in an optimal feeding manner, which was 16.4-fold higher than the control group. To provide an insight into the cell response to ethanol, genes critical to the libertellenone H biosynthesis were successfully cloned and their transcription levels were determined...
February 2016: Bioprocess and Biosystems Engineering
https://www.readbyqxmd.com/read/26323236/%C3%AE-13-c-ch4-reveals-ch4-variations-over-oceans-from-mid-latitudes-to-the-arctic
#20
Juan Yu, Zhouqing Xie, Liguang Sun, Hui Kang, Pengzhen He, Guangxi Xing
The biogeochemical cycles of CH4 over oceans are poorly understood, especially over the Arctic Ocean. Here we report atmospheric CH4 levels together with δ(13)C-CH4 from offshore China (31°N) to the central Arctic Ocean (up to 87°N) from July to September 2012. CH4 concentrations and δ(13)C-CH4 displayed temporal and spatial variation ranging from 1.65 to 2.63 ppm, and from -50.34% to -44.94% (mean value: -48.55 ± 0.84%), respectively. Changes in CH4 with latitude were linked to the decreasing input of enriched δ(13)C and chemical oxidation by both OH and Cl radicals as indicated by variation of δ(13)C...
2015: Scientific Reports
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