石榴果皮过氧化物酶动力学特性的研究

以陕西临潼净皮甜石榴品种为试材,研究果皮中的过氧化物酶（POD）相关特性,确定其催化愈创木酚氧化后产物的最高吸光度值,并分别研究反应后放置时间、pH值、温度、反应时间、酶浓度以及底物浓度等条件对POD活性的影响。结果表明,以愈创木酚为底物时,其最适波长为370nm、最适pH值为6．5、最适温度为40℃、反应时间不宜超过15min、底物浓度宜大于0．03mol／L,反应完成后在40min后测定POD的活性最为稳定。     

金钱草多糖介导的银纳米粒子绿色合成及表征

利用金钱草多糖为还原剂和稳定剂,经前驱体还原法绿色合成了银纳米粒子,考查反应温度、反应时间、前驱体浓度及pH值对银纳米生成的影响,采用紫外光谱和透射电镜对银纳米分散液进行表征和分析。结果表明,中性环境下温度升高至70℃时,多糖呈现出一定的还原能力,随反应时间和前驱体比例的增加,体系中银纳米浓度增强;pH值是影响多糖还原性和银纳米生成速率的关键因素,碱性环境下有利于小粒径、单分散性银纳米的生成,金钱草多糖包覆的银纳米具有优良的储存稳定性。     

马铃薯淀粉制备脂肪模拟物的工艺研究

以马铃薯淀粉为原料,采用高温α-淀粉酶水解马铃薯淀粉,制备低DE值麦芽糊精脂肪模拟物。通过单因素试验,研究了酶添加量、反应时间、反应温度和底物浓度对产品DE值的影响,并通过正交试验确定了制备工艺的最佳条件为:酶添加量为0.02g,温度为95℃,反应时间为10min,底物质量分数为15%,水解产物的DE值为2.96。     

真菌漆酶酶促合成茶黄素工艺的研究

采用漆酶体外酶促氧化茶多酚合成茶黄素。研究结果表明,在实验反应体系中,酶促氧化的最佳条件为:反应温度50℃,最佳pH值2.3,漆酶质量浓度1.8g/L,反应时间1.5h。其中pH值和温度是反应体系中2个极其重要的影响因素。与传统合成方法相比,该方法可以缩短反应时间,提高茶黄素产量。     

植物乳杆菌P48生物转化制备γ-氨基丁酸特性研究

采用微生物细胞生物转化法制备GABA,对比了P48细胞和粗酶转化反应在不同pH值、温度、底物浓度和产物浓度的条件下,各因素对转化液中的GABA含量影响,以期获得转化过程的最佳条件。结果表明,P48细胞转化最适温度为45℃,最适pH值为4.0,当初始底物浓度为100 mmol/L时获得的GABA产率最高,并且产物GABA对转化反应有产物抑制作用。采用细胞的转化反应有更宽的pH值范围,并能在较高的温度下进行。研究结果为采用植物乳杆菌P48细胞生物转化制备γ-氨基丁酸提供了理论基础。     

辛烯基琥珀酸酶解淀粉酯制备条件的研究

以自制的酶解糯米淀粉为原料，对辛烯基琥珀酸糯米淀粉酯制备过程的pH值、反应温度、反应时间与淀粉乳浓度等影响因素进行了研究，得到单因素的最优工艺条件：反应温度35℃、反应时间12h、pH值8．0、淀粉乳质量分数40％、辛烯基琥珀酸酐用量为3％：     

几种玉米种子萌发期淀粉酶活性变化的研究

以玉米种子为材料,采用3、5-二硝基水杨酸法(540 nm处有最大吸收峰),研究了不同的玉米种子在萌发过程中淀粉酶活性的变化以及温度、pH值、底物浓度对淀粉酶活性的影响.结果表明:不同的玉米种子在同一萌发时期淀粉酶活力不同;玉米种子的淀粉酶活力随种子的不断萌发表现为先增加后减小.在pH值为6.8、温度为45℃时酶活力最高,当温度为90℃时酶基本失活.酶活力随底物浓度的增加先增加后趋于稳定.     

马铃薯茎叶再利用研究

为了使被废弃的马铃薯茎叶得到再利用,研究了以乙醚为溶剂的超声波法提取马铃薯茎叶获得精油和精油的N-亚硝基二甲胺合成的阻断作用和对亚硝酸钠的清除作用。研究结果显示,从马铃薯茎叶中以0.52%的产率获得了精油。当马铃薯茎叶精油的用量为1.00mL时,对N-亚硝基二甲胺生成阻断率最大为65.2%;当马铃薯茎叶精油用量为0.30mL时,对NaNO₂的清除率最大达86.8%。     

碱性蛋白酶酶解蛋清工艺条件研究

通过单因素和正交试验研究了蛋清稀释程度、pH值、酶解温度及酶与底物比对碱性蛋白酶酶解蛋清的影响,得到最佳的酶解条件为:将蛋清液稀释至60%后变性,按照酶与底物比为2.5:100(mL:g)加入碱性蛋白酶,酶解温度为60℃,反应初始时不调节pH值,待pH值降至7.5时通过加入NaOH使pH值保持在7.5进行酶解。     

丝瓜超氧化物歧化酶(SOD)酶学特性的研究

为了研究丝瓜超氧化物歧化酶(superoxidedismutase,SOD)酶学特性,本研究应用分光光度计开展了温度、pH、酶体积、反应底物浓度等对酶反应的影响,为丝瓜酶促褐变的研究提供基础。试验结果表明SOD酶最优反应体系为:以底物氮蓝四唑(NBT)为例,最优温度为40℃,最适pH为7.8,其底物浓度为0.08 mol/L,最适酶液体积为0.14 m L,其根据米氏方程:y=0.002 7x-0.013(x=1/V,y=1/S),Km为0.207 9 mol/L。     

药食植物鱼腥草对亚硝化反应抑制作用的研究

在固液比1∶10,提取温度80℃,提取时间60 min条件下,研究五种溶剂提取鱼腥草活性物质中的总黄酮和总酚含量及其对亚硝胺合成的阻断作用与对亚硝酸钠的清除效果。结果表明,55%丙酮提取鱼腥草活性物质中的总黄酮和总酚含量最高,对亚硝胺合成的阻断作用与对亚硝酸钠的清除效果最好,其最佳浓度下提取的鱼腥草活性物质对亚硝胺合成的阻断率达92.81%,对亚硝酸钠的清除率达89.53%;当提取物中的总黄酮含量和VC溶液浓度均为2 mg/mL时,二者对亚硝胺的阻断率分别为51.08%和66.91%,对亚硝酸钠的清除率分别为23.04%和38.22%。     

Application of DMA in Realtime Image Processing

Direct memory access(DMA)is an important technology used for fast speed data transfer in data signal processor(DSP). DMA is able to move data block independent of CPU, and this capability meets real time image processing. TMS320C6201 DSP is taken as an example, and DMA controller characteristic is introduced. According to DMA application in realtime image processing, the specific control ways and realization steps are given out. The research result shows that the flexible control DMA can not only raise image data transfer efficiency but also improve DSP speed.     

不同产量水平稻茬小麦氮素需求特征研究

It is necessary to clarify the nitrogen (N) demand characteristics with yield levels for wheat after rice in the middle and down reaches of the Yangtze River, which could provide theoretical basis for N fertilizer management. Based-on the multi-years and multi-sites wheat experiments in Jiangsu province, this study constructed the datasets of different yield levels derived from different varieties, N rates, densities, and sowing date experiments. N indicators including N requirement per ton grain (N_req), dry matter accumulation (DMA), plant N accumulation (PNA), plant N concentration (PNC), straw N concentration (SNC), grain N concentration (GNC), harvest index (HI), N harvest index (NHI) and N nutrition index (NNI) were analyzed. The results showed that there were not significant differences in N_req among the different yield levels, and the highest N_req was middle-low yield with 27.8 kg t^-1, while the lowest value was 24.8 kg t^-1for low yield level. With the increase of yield levels, DMA, PNA and PNC all showed a gradually increasing trend during maturity stage, and there were significant differences among the different yield levels. There was a significant positive correlation between grain yield and PNA, the DMA and PNA increased with the increase of yield in the sowing-jointing stage, jointing-flowering stage and flowering-maturing stage, but the DMA and PNA proportion in different growth stages showed different trends. The SNC and GNC increased with the increase of yield levels. For SNC, there was no significant difference between the high yield and middle yield level, but it was significantly higher than the low-middle and low yield level. For GNC, there were significant differences among different yield levels except for the middle and low-middle yield level. The HI increased gradually with the increase of the yield levels, and its range was 0.39-0.49. The HI for low-middle and low yields were significantly lower than that of middle and high yield levels, while there were not significant differences in NHI among different yield levels. Its variation range was 0.60-0.96. The NNI gradually increased with the increase of the yield levels, and there was significant difference between different yield levels. The NNI of the high-yield level was higher, and some of the values were greater than 1 which indicating that some experiments had excessive nitrogen fertilizer supply. With the increase of the yield level, the N_req increased first and then decreased, while the DMA, PNA, PNC, SNC, and GNC were gradual increased. The increase of SNC was higher than the GNC, therefore, the extravagant absorption of N by wheat should be avoided in field management. The variation ranges of the HI and NHI were consistent with previous studies. The higher DMA and PNA in the late growth stages were the main reasons for the high yield of wheat. The NNI could be a promising indictor in the field N management of wheat.     

Effects of Nitrogen on Dry Matter Accumulation and Productivity of Three Cropping Systems and Residual Effects on Wheat in Deep Vertisols of Central India

A field experiment was conducted on deep vertisols of Bhopal, India to study the effects of three levels of nitrogen (N), namely 0, 75 and 100 % of the recommended dose of nitrogen (RDN), on the dry matter accumulation (DMA) and productivity of three cropping systems (sole soybean, sole sorghum and soybean + sorghum intercropping) during the rainy season and their residual effect on the subsequent wheat crop during the post-rainy season. During the rainy season, sole sorghum was found to have significantly higher DMA and productivity in terms of soybean equivalent yield (SEY) than sole soybean or soybean + sorghum intercropping. Increasing the N dose from 0 to 100 % RDN significantly improved the DMA and SEY. At a low fertility level (N₀), soybean + sorghum intercropping was found to be more productive, while at a high fertility level (100 % RDN), sole sorghum was more productive than the other two cropping systems. However, during the post-rainy season, sole soybean as the preceding crop gave the highest DMA and seed yield of wheat, which were similar to those found with soybean + sorghum intercropping. Sorghum followed by wheat gave the lowest DMA and seed yield of wheat. Application of 100 % RDN irrespective of cropping system during the preceding crop improved the DMA of wheat but not its seed yield. However, N applied to the wheat crop significantly increased its DMA and seed yield.     

钾硅肥配施对旱地胡麻干物质积累及籽粒灌浆的影响

为探明钾硅养分耦合的产量调控效应,以2个胡麻品种为试验材料,通过裂区设计,研究了钾肥（不施钾、52.5 kg K₂O/hm²和105 kg K₂O/hm²）和硅肥（不施硅和90 kg SiO₂/hm²）用量对胡麻干物质积累及籽粒灌浆特性的影响。结果表明：胡麻品种之间的干物质积累和灌浆特性具有显著差异。施钾显著提高了出苗之后的干物质积累量,2个用量水平平均较不施钾提高11.85%~20.49%,施钾量的增加提高了分茎—青果期间的促生作用;施钾提高了灌浆平均速率,延长了快增持续期、缓增持续期和灌浆活跃期,籽粒产量提高10.79%~19.52%。硅肥对干物质积累和籽粒灌浆无显著的主效,但低供钾下施硅干物质积累量增加了27.96%,钾硅互作影响快增持续期的灌浆速率。与试区相同的土壤肥力条件下,52.5 kg K₂O/hm²钾肥用量具有显著的促生和增产作用,低供钾配施硅肥具有一定的促生作用。     

断根追钾条件下减量施氮对烟株后期氮、钾吸收及烟叶产量质量的影响

以烤烟K326品种为材料, 通过田间试验比较了正常施氮但打顶时不断根不追钾(CK)、正常施氮但打顶时断根并追钾(CK+C+K)、减量施氮(为正常施氮量的80%)但打顶时断根并追钾(RN+C+K)对烟株后期氮、钾吸收和干物质累积及烟叶产量、质量的影响, 以期阐明在打顶时断根追钾条件下, 烟株整个生育期的施氮量是否应该减少的问题。结果表明: 断根追钾明显促进烟株后期的生长。RN+C+K虽少施20%的氮肥, 但其与CK+C+K两处理烟株田间中、上部烟叶的开片和SPAD值, 采烤结束时的干物质和氮、钾累积量, 烟叶的产量、产值以及烟碱和钾含量等质量指标皆优于CK。同时, RN+C+K烟株的干物质和氮、钾累积量以及烟叶产量达到了CK+C+K的97.2%、97.8%、98.9%和98.6%, 而产值比后者高2.0%; 其烤后上部叶的烟碱含量比CK和CK+C+K两处理分别降低了6.7%和4.5%, 而钾含量则分别增加了18.9%和5.6%, 且其他化学成分也更为协调。这说明在断根追钾条件下应该减少氮肥施用量, 以更有利于增加烟农收入、降低肥料成本、节省氮肥资源和提高烟叶质量。     

冬小麦济麦22和春小麦津强8号的产量形成差异分析

为探明冬小麦和春小麦产量形成差异,2016年10月-2017年6月以冬小麦品种济麦22和春小麦品种津强8号为材料,在大田条件下研究了冬小麦和春小麦生育期、叶面积指数、干物质积累及产量构成。结果表明,春小麦出苗比冬小麦延长8d,营养生长期缩短77~78d,灌浆期延长1~2d,全生育期缩短143~144d。拔节期和开花期,春小麦和冬小麦的叶面积指数无显著差异,但灌浆期春小麦叶面积指数比冬小麦叶面积指数增加6.34%~7.67%,不同生育时期春小麦和冬小麦干物质积累量无差异。春小麦收获穗数和千粒重比冬小麦分别增加2.35%~5.29%和4.28%~5.13%,但穗粒数比冬小麦少1.4~2.3,春小麦与冬小麦理论产量和实际产量均无显著差异。综上所述,春小麦可通过增加播量,增加穗数,保持稳定的叶面积指数和干物质积累量,实现小麦稳产,可为区域变革麦-玉种植制度,实现麦-玉周年双机收子粒提供理论支撑。     

基于归一化法的烤烟干物质积累建模与特征分析

为探讨不同株型烤烟品种干物质积累动态模型和变化特征,实现不同品种烤烟干物质积累的有效预测,以不同株型品种云烟97、NC71、K326为材料,采用田间实测和数值模拟方法研究4个密度(13 890、15 150、16 660和18 510株hm~(–2))水平下烤烟干物质积累动态,分析关键生长参数特征,以期为烤烟合理密植、烟叶增产提供新的理论与方法。结果表明:(1)基于归一化法筛选并建立了相对干物质积累量与相对生长时间的干物质积累动态模型(MMF),方程表达式为y=(ab+cx~d)/(b+x~d),模拟准确度k值在0.9032~1.0482之间,决定系数R~2在0.94以上,进一步推导发现,方程具有过原点性、有界性、单调递增性等特点,符合生物学意义,能较好地模拟烤烟干物质积累动态特征;利用该模型分析积累特征参数,将烤烟干物质积累过程划分为缓慢增长期、快速增长期、减速增长期。(2)随着种植密度的增加,烤烟速率峰值出现时间(T_m)、快速增长期开始时间(RT_1)、结束时间(RT_2)均有不同程度提前;密植条件下(D3、D4),NC71和K326快速增长期持续时间(T_d)及其积累比例(R_a)明显提升;通径分析表明,T_d、R_a均能影响烤烟最终干物质积累水平,其与干物重均显著(0.6500*)或极显著(0.7758**)正相关,其中R_a对干物重直接通径系数达1.7097,对回归方程的总贡献率也达1.3264。(3)耐密性表现为筒型鼓型塔型,对应品种K326、NC71、云烟97的适宜密度分别为18 510株hm~(–2)(D4)、16 660株hm~(–2)(D3)、15 150(D2)~16 660(D3)株hm~(–2)。     

具有抗肿瘤和抗菌活性的长效改性蜂毒肽(GPG)设计及其生物活性评价

为获得低毒、具有抗肿瘤和抗菌活性的长效改性蜂毒肽,提高蜂毒肽的临床应用价值,本试验以多肽构效关系为指导,选择两亲性α-螺旋型阳离子多肽分子结构为改性蜂毒肽的设计模板,用杂合肽法设计了一系列多肽序列,用生物信息学工具比较它们的生物活性并进行初选,再用固相法合成初选所得少量序列的多肽,比对合成多肽的生物活性,精选获得生物活性高的多肽。实验表明精选所得多肽具有长效性,确定其为设计目标肽(GPG),当GPG浓度为150 μmol/L时,其溶血率为零;浓度为33.3 μmol/L时,其对小鼠肝癌细胞(H₂₂)、人肝癌细胞(SMMC-7721)和人结肠癌细胞(SW-1116)的抑癌率分别为(78.0±0.6)%、(74.0±1.2)%、(74.0±0.5)%;浓度为100 μmol/L时,其对大肠杆菌的抑菌圈直径为(15.18±0.30) mm;当注射GPG（100 μmol/只）时,能延长致死剂量大肠杆菌（5×10⁷个/只）攻毒的小鼠寿命63.2 h。该设计省时省力地优选得溶血活性低、抗癌抗菌活性强、半衰期长的全新结构目标肽GPG,其有临床应用前景;以GRGDSP肽链为多肽氮端端基,可提高其生物活性及半衰期。     

On arsenic speciation in the Tagus estuary

New evidence is presented pointing to the presence in estuarine waters both of trimethylarsenic forms (TMA) and of an organoarsenical component refractory to the hydride method.Although not previously detected in estuarine and coastal studies, TMA concentrations were measured in the Tagus estuary in August 1984. The results are presented together with total inorganic, monomethyl (MMA) and dimethyl arsenic (DMA) species quantified in the same occasion. Further digestion of a separate water sample gave positive increments for the methylarsenicals (MMA+DMA+TMA), with special relevance for DMA, suggesting the presence of a heavier organo-arsenical, undetectable in undigested samples with our current analytical capabilities. This component seems to be present in concentrations greater than MMA and TMA. That same sample was passed through a molecular fractionation scheme to get indications of the molecular weight of that unknown component. The results suggest a molecular weight of less than 210 although the limitations of the method do not allow a definitive conclusion.