豆制品中胰蛋白酶抑制剂活性测定方法研究     

王英男  修建成  富校轶  李家栋 《大豆科技》2006,(2):31-32

利用紫外分光光度计，对豆制品中胰蛋白酶抑制剂在抑制牛胰蛋白酶活性反应前后的吸光值差异制作差值曲线，从而得出斜率与抑制剂活性之间关系的方法。并通过反复的实验对比，最终可以快速准确地测定大豆制品中胰蛋白酶抑制剂活性。  相似文献   

改性尿素追施对冬小麦和夏玉米季氮素挥发和淋溶的影响     

肖强  李丽霞  李鸿雁  衣文平  邹国元  刘建斌  孙世友 《水土保持学报》2020,34(4):270-279

以NBPT(N-丁基硫代磷酰三胺)和DMPP(3,4-二甲基吡唑磷酸盐)为复合抑制剂,利用转鼓喷涂工艺,开发出新型复合型抑制剂涂覆尿素肥料,采用扫描电镜和能谱仪分析其涂覆效果。通过田间试验系统对比评价了追施不同氮肥对调控氮素的特征效果。试验设置5个处理:(1)不施氮肥(CK);(2)农民习惯追施尿素(CU);(3)优化追施尿素(CUU);(4)优化追施抑制剂涂覆尿素(CUY1);(5)优化追施抑制剂涂覆尿素(CUY2)。在夏玉米喇叭口期、冬小麦拔节期追施氮肥后的15天内进行田间原位连续动态观测。电镜和能谱结果表明,复合抑制剂均匀涂覆于尿素表面,形成薄而致密、光滑的涂覆层,该涂覆层均匀分布有磷和硫2种元素,表明复合抑制剂与尿素已有效结合。田间试验结果表明,在同等优化施氮量下与普通尿素相比,夏玉米和冬小麦季追肥后CUY1和CUY2处理氨挥发分别降低55.19%,32.15%和52.46%,39.43%。夏玉米季追肥后,0-20 cm土层CU、CUU处理土壤硝态氮含量于第5天达到峰值,到后期已显著低于CUY1、CUY2处理,CUY2处理稳定硝态氮的效果更好。冬小麦季追肥后,0-20 cm土壤硝态氮含量CU、CUU处理分别在第5,3天达到峰值,CUY1、CUY2处理于第11天达到峰值后,硝态氮含量已显著高于相同施氮量的CUU处理。在保证产量和净收益的同时,抑制剂涂覆尿素显著降低了追施氮素的氨挥发和淋溶损失浓度,其中冬小麦季CUY1处济效益较好,夏玉米季CUY2调控氮素的效果最佳,减少向下淋溶的效果明显。  相似文献   

施氮及添加硝化抑制剂对苜蓿草地N₂O排放的影响   总被引：1，自引：0，他引：1  

倪红  杨宪龙  王刚  来兴发  邓建强  沈禹颖 《中国生态农业学报》2020,28(3):317-327

为探究旱作紫花苜蓿(MedicagosativaL.)栽培草地氧化亚氮(N_2O)排放对施氮水平及添加硝化抑制剂的响应特征,采用传统静态箱法研究了不同施氮水平[0kg(N)·hm~(-2)(N0)、 50kg(N)·hm~(-2)(N50)、 100kg(N)·hm~(-2)(N100)和150kg(N)·hm~(-2)(N150)]以及添加硝化抑制剂双氰胺(DCD)150kg(N)·hm~(-2)(N150+DCD)对陇东苜蓿草地N_2O排放特征的影响。结果显示,监测期内N0、N50、N100和N150处理N_2O平均排放速率分别为3.5μg·m~(-2)·h~(-1)、4.1μg·m~(-2)·h~(-1)、5.0μg·m~(-2)·h~(-1)和6.1μg·m~(-2)·h~(-1),随着施氮梯度的增加, N_2O排放速率呈增加趋势。添加硝化抑制剂DCD对N_2O排放产生明显的抑制作用。与N150处理相比, N150+DCD处理下苜蓿草地N_2O平均排放速率下降50.7%, N_2O累计排放量显著降低61.6%(P0.05)。施氮对苜蓿产量没有显著影响,而N0、N50、N100和N150处理下单位苜蓿产量N_2O排放量随氮肥梯度的增加而增加,各处理分别为6.5 mg·kg~(-1)、7.8 mg·kg~(-1)、11.3 mg·kg~(-1)和12.5 mg·kg~(-1)。N_2O排放受土壤含水量影响深刻,生长季N_2O排放通量与土壤水分呈显著正相关关系(P0.05),而与土壤温度无显著相关性(P0.05)。综上,旱作紫花苜蓿栽培草地N_2O排放通量随施氮水平的增加明显增加,在相同施氮水平下添加硝化抑制剂DCD能显著抑制N_2O排放。相关研究结果对于该区域苜蓿草地合理施肥以及N_2O减排具有一定的实践指导意义。  相似文献   

秸秆覆盖深松对夏玉米田土壤酶活性的影响     

郭书亚  尚赏  王坤  汤其宁  张艳  付国占  卢广远 《中国农学通报》2022,38(25):96-101

探讨秸秆覆盖深松对夏玉米田土壤酶活性的影响。采用4种保护性耕作模式(SS+M、SS+NM、NT+M、NT+NM)在河南西平进行连续3年田间试验,研究不同处理对土壤脲酶、土壤碱性磷酸酶、土壤蔗糖酶、土壤过氧化氢酶活性的影响。结果表明,4种保护性耕作方式下土壤脲酶、土壤碱性磷酸酶、土壤蔗糖酶、土壤过氧化氢酶活性均随着土层的加深而降低。4种酶的活性随着玉米生育期的变化而变化,即随着玉米生育时期的推进,土壤酶活性从播种到花后45天先升高后下降,土壤脲酶和土壤蔗糖酶活性在开花期达到最大值,而土壤碱性磷酸酶和土壤过氧化氢酶活性在花后15天达到最大值。在0～5 cm和5～10 cm土层,秸秆覆盖处理下土壤酶活性显著高于不覆盖处理,SS+M>NT+M>SS+NM>NT+NM;在10～20 cm土层,NT+M处理下土壤酶活性急剧下降;在20～30 cm和30～40 cm土层,在大多数时期深松处理下土壤酶活性显著高于免耕处理,SS+M>SS+NM>NT+M>NT+NM。在豫南雨养区实施秸秆覆盖深松能够提高土壤的酶活性,值得推广。  相似文献   

拟南芥和水稻cystatin基因家族的生物信息学分析     

杨泽峰  顾世梁  许花  徐辰武 《扬州大学学报(农业与生命科学版)》2007,28(3):51-57

利用已经分离的植物半胱氨酸蛋白酶抑制剂(cystatin)基因的cystatin结构域为检索序列在基因组水平上对拟南芥和水稻中的cystatin基因家族的成员进行分析;同时利用这些基因编码的蛋白质序列构建系统发生树,并对这些蛋白序列的保守序列进行分析;最后在GenBank的EST数据库中查找这些基因的ESTs表达序列。结果表明:1结合结构域的鉴定、多序列联配以及MEME分析最终确定了7个拟南芥和11个水稻的cystatin基因。2系统发生分析表明,cystatin基因的基本特征很可能是在拟南芥和水稻的分离之前就已经形成。3 cystatin结构域在蛋白质间高度保守。4拟南芥和水稻的cystatin基因主要在花、叶、根、种子和愈伤组织中表达,这有助于植物避免昆虫的侵害。  相似文献   

红豆草胰蛋白酶抑制剂的部分性质     

侯新东  王希东  盛桂莲  张桦  喻梅辉 《江苏农业学报》2007,23(4):295-298

通过胰蛋白酶偶联的Sepharose 4B亲和柱,从红豆草茎叶中分离纯化出一种胰蛋白酶抑制剂,对其抑制剂的抑制活力、摩尔抑制比和抑制活性中心等进行研究.结果表明:红豆草胰蛋白酶抑制剂对胰蛋白酶具有抑制作用,红豆草胰蛋白酶抑制剂对胰蛋白酶的摩尔抑制比为1∶2;用氨基酸修饰法,进一步证明红豆草胰蛋白酶抑制剂的两个活性中心分别是精氨酸残基和赖氨酸残基.  相似文献   

Effects of pirenzepine on expression of MMP-2 and TIMP-2 in stroma of sclera in chick myopic eyes     

DAI Shu-zhen  ZHANG Li  WANG Li-ya  ZENG Jun-wen 《园艺学报》2012,28(8):1494-1499

AIM:To observe the effect of intravitreal injection of pirenzepine on form-deprivation myopia in chicks. METHODS:Forty-one day old chicks were randomly divided into 4 groups:normal control group, form deprivation group, vehicle control group and pirenzepine injection group. The right eyes of all chicks were used as experimental eyes. The deprived eyes in vehicle control group and pirenzepine injection group received daily intravitreal injection of vehicle control solution(0.01 mol/L PBS) and pirenzepine(1%in PBS), respectively. Optical examinations such as refraction, axial length and equatorial diameter were made at the end of the 5th day. The mRNA and protein levels of matrix metalloproteinase 2(MMP-2) and tissue inhibitor of metalloproteinase-2(TIMP-2), and the activity of MMP-2 were detected by RT-PCR, Western blotting and zymography analysis,respectively. RESULTS:Refraction, axial length and equatorial diameter of the eyes in pirenzepine injection group were significantly lower than those in form deprivation group and vehicle control group(P<0.05), but those were higher(P<0.05) and the eyes were relatively myopic as compared with normal control group. The mRNA expression, protein le vels and activity of MMP-2 in pirenzepine group were significantly higher than those in normal control group(P<0.01), and were significantly lower than those in form deprivation group and vehicle control group(P<0.01, P<0.01). The mRNA and protein levels of TIMP-2 in pirenzepine group were significantly lower than those in normal control group(P<0.01), and was significantly higher than those in form deprivation group and vehicle control group(P<0.01, P<0.01). CONCLUSION:Intravitreal injection of pirenzepine may partly prevent form-deprivation myopia by modulating the expression of MMP-2 and TIMP-2 in the fibrous layer of sclera.  相似文献   

Influence of moisture regime on inhibition of nitrification by DCD     

Rajendra Prasad 《Archives of Agronomy and Soil Science》2013,59(4-5):495-500

A laboratory study at the Indian Agricultural Research Institute, New Delhi showed that DCD was an efficient nitrification inhibitor under field capacity moisture (???30 kPa) but not so under submerged soil conditions. Nitrification inhibition by DCD was 79.6% after 1 week of incubation and decreased to 59.3% after 3 weeks of incubation under field capacity moisture, while it was only 19.3% after 1 week of incubation and 10.6% and 18.4% after 2 and 3 weeks of incubation under submergence, respectively. DCD can play an important role in reducing N losses from agricultural fields.  相似文献   

Advances in prevention of nonsteroidal anti-inflammatory drug-induced gastropathy by proton pump inhibitor     

ZHENG Li-bo  ZHANG Xiao-lan 《园艺学报》2010,26(11):2274-2279

Nonsteroidal anti-inflammatory drugs (NSAIDs) are powerful in anti-inflammatory, analgesic and antirheumatic effects, and widely used in treating the corresponding diseases. Over the years, many new dosage forms and structures of NSAIDs appear since aspirin was developed 112 years ago. However, the universal use of NSAIDs produces unavoidable mucosal lesions in gastrointestinal tract. As yet, proton pump inhibitor (PPI) has been used in the treatment of gastropathy induced by NSAIDs. This article will focus on the advances in prevention of NSAIDs-induced gastropathy by proton pump inhibitor.  相似文献   

PCR-based detection of sterol demethylation inhibitor-resistant strains of Penicillium digitatum     

Hamamoto H  Hasegawa K  Nakaune R  Lee YJ  Akutsu K  Hibi T 《Pest management science》2001,57(9):839-843

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