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21.
海栖热袍菌极端耐热木聚糖酶B的提纯 总被引：6，自引：0，他引：6
克隆并在大肠杆菌中表达的海栖热袍菌的 xyn B基因 ,其表达产物木聚糖酶 B的 C 末端带有 6×His标签 ,研究了这种基因重组酶的提纯方法。通过对粗酶提取液的热变性处理 ,Ni NTA亲和柱层析和离子柱层析 ,最终得到了电泳纯的木聚糖酶 B,提纯倍数 4 4.4 ,得率 11。SDS PAGE法测定木聚糖酶 B的相对分子质量为 4 2 ku,与理论推算值 4 2 333u相吻合 相似文献
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Summary Calcium uptake into potato plants was examined using test solutions containing 5% safranin dye (C20H19N4C1 mw 350.85) and the radiotracer45CaCl2. When minitubers were suspended in test solutions for up to 5 days, safranin moved into the outer pith tissues while45Ca2+ was located throughout the pith. Ca2+ is apparently taken up directly from the tubersphere by a slow diffusion process. Plantlets with one microtuber were used
to investigate calcium uptake via basal roots.45Ca2+ was well ahead of the safranin dye front in all plantlet stems.45Ca2+ in shoot tips was significantly greater than in microtubers and no safranin entered the microtubers. Greenhouse-grown ex
vitro plantlets with minitubers attached were used to determine the relative uptake by basal and stolon roots. Basal root
feeding contributed significantly more45Ca2+ to shoot tips and tubers than stolon root feeding while combined feeding gave the greatest shoot tip and tuber45Ca2+ levels. 相似文献
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Habib-ur-Rahman Muhammad Raza Ahsan Ahrends Hella Ellen Hüging Hubert Gaiser Thomas 《Precision Agriculture》2022,23(3):912-938
Precision Agriculture - Crop cultivation provides ecosystem services on increasingly large fields. However, the effects of in-field spatial heterogeneity on crop yields, in particular triticale,... 相似文献
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Micropropagated potato plantlets (Solanum tuberosum cvs Acadia Russet, Red Gold, Red Pontiac, and Russet Burbank) were used to test the effects of exposure to ultra violet rays (UV) or inclusion of vitamin D3 (cholecalciferol) in the test solution on plantlet calcium (Ca) uptake. Ca uptake was determined by measuring shoot tissue45Ca2+ concentration inex vitro plantlets placed into test solutions containing radiolabelled calcium (45CaCl2). Shoot tissue45Ca2+ concentration was very significantly increased in all cultivars exposed for 24 h to UV treatment compared with control plantlets. This increase in shoot45Ca2+ concentration was similar (three cultivars) or greater (one cultivar) than that caused by 10 ing L?1 vitamin D1 in the test solution. When plantlets were exposed to UV, then placed for 24 h in the dark, significantly greater shoot45Ca2+ concentrations occurred compared with plantlets tested immediately following treatment. This suggests that a change in the UV-elicited cellular product occurred during the dark interval that promoted more Ca uptake into plantlets. 相似文献
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Acceleration of Microtuber Induction in Potato by Cytokinine and Photoperiod Adjustment 总被引：1，自引：0，他引：1
M F Alam N Ahsan M M Hossain S Parvez A M Swaraz R Islam 《中国马铃薯》2003,17(5):257-261
INTRODUCTIONPotato (SolanumtuberosumL)ismostproduc tive,common ,andmultiusehorticulturalvegetablecrop .Itconqueredabout 5 0 %amongrootcroppro ductionintheworld[1] .Invegetatively propagatedcrops,oncesystematicallyinfectedwithaviraldis ease ,thepathogencanbepassedfromonevegetativegenerationtonext .Especiallyinpotato ,contamina tionbyapathogencanseverelyreducethetotalyieldofthecrop[2 ] .Sincemanytropicalcountriesarenotabletoproducehighqualityseedtubersduetoalackofvector -freeproductionarea… 相似文献
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Constituents and cytotoxicity of Zanthoxylum rhesta stem bark 总被引：2，自引：0，他引：2
3,5-Dimethoxy-4-geranyloxycinnamyl alcohol (1), 8-methoxy-N-methylflindersine (2), xanthyletin and sesamin have been isolated from petroleum ether extract of the stem bark of Zanthoxylum rhesta. The petroleum ether extract and 8-methoxy-N-methylflindersine showed cytotoxicity on brine shrimp nauplii. 相似文献
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Aoki H Ahsan MN Matsuo K Hagiwara T Watabe S 《Journal of agricultural and food chemistry》2003,51(3):777-783
Three gelatinolytic proteases (A1, A2, and B) were purified using a synthetic substrate, DNP-Pro-Gln-Gly-Ile-Ala-Gly-Gln-d-Arg, from the hepatopancreas of Northern shrimp (Pandalus eous) by several chromatographic steps involving hydroxyapatite column chromatography, gel filtration on Superdex75, and ion-exchange chromatography on a MonoQ column. Collagenolytic proteases A2 and B, but not protease A1, were demonstrated to digest native porcine type I collagen at 25 degrees C and pH 7.5. Further characterizations of these two collagenolytic proteases showed that the pH optimum of enzyme A2 against DNP-peptide was found to be 11, whereas that of enzyme B was 8.5. The optimum temperature ranged between 40 and 45 degrees C for both enzymes, although enzyme B appeared to be thermally more stable than enzyme A2 at pH 7.5. Both enzymes were strongly inhibited by PMSF and antipain, which suggests that they belong to collagenolytic serine proteases. 相似文献
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The influence of seed priming with sorghum water extract (SWE) and benzyl amino purine (BAP) on germination metabolism and early seedling growth of wheat was evaluated in this study. For priming, wheat seeds were soaked in SWE (5%), BAP (5 mg L?1) alone and mixed with nonionic surfactant Tween-80 (0.05%). All the seed priming treatments significantly (p ≤ 0.05) improved the germination metabolism and early seedling growth as compared with dry seeds. Seed priming with combination of SWE, BAP and Tween-80 was the most effective treatment in improving the final germination percentage (34%), number of tillers per pot (50%), fresh weight (32%), dry weight (63%), chlorophyll contents (7%) and total phenolic contents (36%) over dry seed control. Similarly, maximum total soluble proteins, total soluble sugars and α-amylase activity were observed from the combined priming with SWE, BAP and Tween-80. Total soluble proteins were maximum in growing seedlings followed by germinating seeds than primed seeds. The germination and growth improvement by priming with SWE was comparable to BAP which makes it a cost-effective natural growth regulator. Combined applications are more effective, which may be due to enzymatic regulation in a synergistic manner. 相似文献
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