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51.
A DNase present in commercial preparations of Aspergillus oryzae alpha-amylase was purified 1550-fold in 25% yield by acetone precipitation and by chromatography on diethylaminoethyl- and carboxymethylcellulose. The enzyme was isolated free of contaminating RNases and DNases. The molecular weight of the enzyme determined by gel filtration on Sephadex G-100 was 48 000, while a molecular weight of 58 000 was determined for the single band observed upon polyacrylamide gel electrophoresis in sodium dodecyl sulfate. The isoelectric point of the DNase is 9.2. The enzyme hydrolyzed only DNA with a pH optimum of 8.2 and was activated by Co2+, and to a lesser extent by Mg2+ and Mn2+. Native DNA was a better substrate than heat-denatured DNA. Enzymatic digests of calf thymus and E. coli DNA yielded oligomers of chain lengths ranging from 10 to 200, with mono- and small oligonucleotides (chain length less than 5) detected only when large (100 mg) amounts of DNA were fractionated by column chromatography on diethylaminoethyl-Sephadex A-25 in 7 M urea. The digestion products contained 5'-terminal phosphate groups and mostly adenosine at the 3' and guanosine and adenosine at the 5' ends. 相似文献
52.
James L. Whitlock 《Geomicrobiology journal》2013,30(3-4):241-249
A biological treatment plant is utilized at the Homestake Mine in Lead, SD, to effect detoxification of a daily discharge of 4 million gallons of wastewater. The wastewater matrix requiring treatment contains cyanide, ammonia, toxic heavy metals, and a variable component of toxic chemicals associated with extractive metallurgy and mining operations. Rotating biological contactors (RBCs) are used to attach the biofilm. Cyanides and heavy metals concentrations are reduced by 95–98%. The treated discharge makes up as much as 60% of the total flow in a cold‐water trout fishery. This receiving stream, which remained lifeless for over 100 years as a mine drainage, has now become an established trout fishery and recently yielded a state record trout. 相似文献
53.
以普通小麦品种‘轮选988’为材料,采用溶液培养法,研究了根施不同浓度甜菜碱(1.0、2.0、3.0、4.0、5.0、10.0、15.0、20.0mmol·L~(-1))对镍(100μmol·L~(-1) NiSO_4)胁迫下小麦根系生长的影响,以及4.0mmol·L~(-1)甜菜碱处理镍胁迫幼苗根系相关抗逆生理生化指标的变化。结果表明:(1)与不施加镍对照相比,镍胁迫下小麦幼苗的根长、株高、鲜重和干重分别显著降低了14.7%、11.7%、15.0%和16.7%。(2)与单独镍胁迫处理相比,小麦幼苗的根长、株高、鲜重和干重均随着根施甜菜碱的浓度逐渐增加且呈先升后降的趋势,并以4.0mmol·L~(-1)外源甜菜碱处理效果较佳。(3)与单独镍胁迫处理相比较,在4.0mmol·L~(-1)外源甜菜碱处理下,小麦幼苗根系超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)和抗坏血酸过氧化物酶(APX)活性分别升高了284.7%、40.3%、82.9%和20.4%,超氧阴离子自由基(O-·2)含量、过氧化氢(H_2O_2)含量和丙二醛(MDA)含量分别显著降低了50.6%、38.4%和40.6%,可溶性糖含量及游离脯氨酸(Pro)含量分别显著降低了19.2%、45.4%,而根系活力大幅上升了358.0%。研究认为,根施适宜浓度外源甜菜碱可显著增强小麦幼苗根系的抗氧化能力,恢复根系活力,从而有效减弱镍胁迫对小麦幼苗生长的伤害。 相似文献
54.
Data for the historical years 1970 and 1995 and the FAO-Agriculture Towards 2030 projection are used to calculate N inputs (N fertilizer, animal manure, biological N fixation and atmospheric deposition) and the N export from the field in harvested crops and grass and grass consumption by grazing animals. In most industrialized countries we see a gradual increase of the overall N recovery of the intensive agricultural production systems over the whole 1970-2030 period. In contrast, low N input systems in many developing countries sustained low crop yields for many years but at the cost of soil fertility by depleting soil nutrient pools. In most developing countries the N recovery will increase in the coming decades by increasing efficiencies of N use in both crop and livestock production systems. The surface balance surplus of N is lost from the agricultural system via different pathways, including NH3 volatilization, denitrification, N2O and NO emissions, and nitrate leaching from the root zone. Global NH3-N emissions from fertilizer and animal manure application and stored manure increased from 18 to 34 Tg·yr-1 between 1970 and 1995, and will further increase to 44 Tg·yr-1 in 2030. Similar developments are seen for N2O-N (2.0 Tg·yr-1 in 1970, 2.7 Tg·yr-1 in 1995 and 3.5 Tg·yr-1 in 2030) and NO-N emissions (1.1 Tg·yr-1 in 1970, 1.5Tg·yr-1 in 1995 and 2.0 Tg·yr-1 in 2030). 相似文献
55.
Whitlock GA Conlon K McMurray G Roberts LR Stobie A Thurlow RJ 《Bioorganic & medicinal chemistry letters》2008,18(9):2930-2934
Novel 2-imidazoles have been identified as potent partial agonists of the α1A adrenergic receptor, with good selectivity over the α1B, α1D and α2A receptor sub-types. Sulfonamide 23 possessed attractive drug-like properties with respect to physicochemical and ADME properties and wide ligand selectivity. 相似文献
56.
Roberts LR Bryans J Conlon K McMurray G Stobie A Whitlock GA 《Bioorganic & medicinal chemistry letters》2008,18(24):6437-6440
A novel series of central nervous system (CNS) penetrant indane 2-imidazoles have been identified as potent, partial agonists of the alpha(1A) adrenergic receptor, having good selectivity over the alpha(1B), alpha(1D) and alpha(2) sub-types. A key structural motif to impart selectivity is a methylene spacer between the indane and a pendant substituent, which includes heterocycles, sulphones and ethers. Introduction of an ortho-halogen to this group led to a lowering of intrinsic efficacy (E(max)). 相似文献
57.
Fish PV Barta NS Gray DL Ryckmans T Stobie A Wakenhut F Whitlock GA 《Bioorganic & medicinal chemistry letters》2008,18(15):4355-4359
Derivatives of (3S)-N-(biphenyl-2-ylmethyl)pyrrolidin-3-amine are disclosed as a new series of noradrenaline reuptake inhibitors (NRI). Carboxamide 9e, carbamate 11b and sulfonamide 13a were identified as potent NRIs with excellent selectivity over SRI and DRI, good in vitro metabolic stability and weak CYP inhibition. Carbamate 11b demonstrated superior transit performance in MDCK-mdr1 cell lines with minimal P-gp efflux which was attributed to reduced HBA capacity of the carbamate group. Evaluation in vivo, in rat microdialysis experiments, showed 11b increased noradrenaline levels by 400% confirming good CNS penetration. 相似文献
58.
Gavin A. Whitlock Paul E. Brennan Lee R. Roberts Alan Stobie 《Bioorganic & medicinal chemistry letters》2009,19(11):3118-3121
Novel imidazole frameworks have been identified as potent partial agonists of the α1A adrenergic receptor, with good selectivity over the α1B, α1D and α2A receptor sub-types. Nitrile 28 possessed attractive CNS drug-like properties with good membrane permeability and no P-pg mediated efflux. 28 also possessed excellent solubility, metabolic stability and wide ligand selectivity. 相似文献
59.
Background
The chloroplast trnH-psbA spacer region has been proposed as a prime candidate for use in DNA barcoding of plants because of its high substitution rate. However, frequent inversions associated with palindromic sequences within this region have been found in multiple lineages of Angiosperms and may complicate its use as a barcode, especially if they occur within species.Methodology/Principal Findings
Here, we evaluate the implications of intraspecific inversions in the trnH-psbA region for DNA barcoding efforts. We report polymorphic inversions within six species of Gentianaceae, all narrowly circumscribed morphologically: Gentiana algida, Gentiana fremontii, Gentianopsis crinita, Gentianopsis thermalis, Gentianopsis macrantha and Frasera speciosa. We analyze these sequences together with those from 15 other species of Gentianaceae and show that typical simple methods of sequence alignment can lead to misassignment of conspecifics and incorrect assessment of relationships.Conclusions/Significance
Frequent inversions in the trnH-psbA region, if not recognized and aligned appropriately, may lead to large overestimates of the number of substitution events separating closely related lineages and to uniting more distantly related taxa that share the same form of the inversion. Thus, alignment of the trnH-psbA spacer region will need careful attention if it is used as a marker for DNA barcoding. 相似文献60.
Richard Whitlock Jeff S. Healey Stuart J. Connolly Julie Wang Matthew R. Danter Jack V. Tu Richard Novick Stephen Fremes Kevin Teoh Vikas Khera Salim Yusuf 《CMAJ》2014,186(12):905-911