Breeding of tetra null soybean (Glycine max) for lipoxygenase,kunitz trypsin inhibitor,lectin, and 7S α' subunit proteins

Soybean seed includes various bioactive substances. Also, they contain a variety of antinutritional factors including lipoxygenase, Kunitz trypsin inhibitor (KTI), lectin, and 7S α' subunit proteins. The genetic removal of these proteins will improve the nutritional value of soybean seed. The objective of this research was to breed new soybean with tetra recessive alleles (lox1lox2lox3/lox1lox2lox3‐ti/ti‐le/le‐cgy1/cgy1) for lipoxygenase, KTI, lectin, and 7S α' subunit proteins. Seven parents were used to breed tetra null strain. SDS‐PAGE and Western blot analysis were used to determine the presence or absence of lipoxygenase, 7S α' subunit, KTI, and lectin proteins in mature seed. Tetra null soybean line has a purple flower, determinate growth habit, tan pod, and yellow seed coat colour. Stem height of the breeding line was 62.3 cm. The 100‐seed weight of the breeding line was 27.1 g and yield (t/ha) was 2.84. This is the first soybean strain with lox1lox2lox3/lox1lox2lox3‐ti/ti‐le/le‐cgy1/cgy1 genotype (absence of lipoxygenase, KTI, lectin, and 7S α' subunit proteins).     

花生种子脂肪氧化酶鉴定方法研究

借鉴其他作物脂肪氧化酶的鉴定方法,根据花生脂肪氧化酶同工酶等电点差异,利用等电聚焦电泳技术,建立花生脂肪氧化酶同工酶的鉴定方法,并探讨其适宜实验条件。该方法具有分辨率高、特异性强的特点,为广泛开展花生脂肪氧化酶筛选鉴定工作奠定基础。     

Lipid composition and post-wounding degradation in potato slices from cultivars differing in susceptibility to autolysis

Summary The effect of cutting on lipid content and degradation were compared in tubers of potato cultivars resistant (Acresta, Aminca, Eba) or susceptible (Kastor, Pana, Tasso) to autolysis. Susceptible cultivars showed greater degradation of lipids and phospholipids as well as higher activity of lipid acyl-hydrolase. No significant differences were detected in the activity of lipoxygenase in the tissues of the studied cultivars.     

Distribution of Enzymes in Wheat Flour Mill Streams

The distribution of alpha -amylase, protease, lipoxygenase, polyphenol oxidase and peroxidase in wheat roller flour mill streams was studied. Break flours had relatively less alpha -amylase and protease activity than reduction flours both on flour weight and a protein basis. Among the different flour streams, the 5^thand 6^threduction passage had the highest alpha -amylase activity, while the 4^threduction passage had the highest protease activity. The lipoxygenase activity was concentrated mostly in the last break and the reduction streams, whereas polyphenol oxidase activity was highest in break flour streams. Peroxidase activity was distributed unevenly among the different mill streams. The lipoxygenase, polyphenol oxidase and peroxidase were highly concentrated in different bran fractions. Except for protease, the other enzymes were concentrated in the «atta», a milling by-product comprising refined flour, bran and shorts; and are least active in semolina (farina).     

Response dynamics of three defense related enzymes in cotton leaves to the interactive stress of Helicoverpa armigera (Hübner) herbivory and omethoate application

In order to explore the response dynamics of the activities of defense related enzymes in cotton leaves towards the interactive stress of Helicoverpa armigera herbivory and omethoate application, the activities of phenylalanine ammonia-lyase(PAL), lipoxygenase(LOX), and polyphenol oxidase(PPO) were examined from 6 to 126 h after cotton leaves were treated 12 h of H. armigera herbivory, and then sprayed with 800 mg L–1 omethoate. The results showed that the changes in the activities of PAL, LOX and PPO that occured under the interactive stress of H. armigera herbivory and omethoate application reflected the interactive effects of the two stresses on cotton defense. The similarity between the response dynamics of PAL, LOX, and PPO activities in cotton leaves under the interactive stress and that under H. armigera herbivory treatment alone showed that the induction of H. armigera herbivory on the activities of PAL, LOX and PPO in cotton leaves played a leading role in the interactive effects, and the effect of omethoate application played only a minor role. A joint factor analysis was performed according to a method which has been used to analyze the joint toxicity of pesticides; this analysis sought to clarify if there was a synergistic, antagonistic, or additive effect on PAL, LOX, and PPO activity in cotton leaves resulting from the interactive H. armigera herbivory and omethoate treatment. In the interactive effect on the response of PAL activity in cotton leaves, antagonistic effects of the omethoate application towards H. armigera herbivory were observed at 6 and 12 h. Synergistic effects were then observed at 18 and 30 h. Antagonistic effects were observed from 54 to 78 h and synergistic effects were finally observed at 126 h. The correlation between H. armigera herbivory and omethoate application in the interactive effect on cotton defense responses of LOX activity also fluctuated from synergism to antagonism during the time course. In the interactive effect on PPO activity, only antagonism was observed between H. armigera herbivory and omethoate application. In the interactive stress of H. armigera herbivory and omethoate application on cotton defense responses, omethoate affected the defense responses of cotton to H. armigera herbivory by producing antagonistic and synergistic effects. These results will be useful to understand the relationship between host plant and herbivorous pest.     

大豆凝集素和脂肪氧化酶双价RNAi表达载体的构建及其遗传转化

【目的】应用RNA干扰技术,同时抑制大豆凝集素(Soybean agglutinin,SBA)和脂肪氧化酶(Lipoxygenase,Lox)基因在种子中的表达,改良大豆营养品质,为培育优质大豆材料奠定基础。【方法】根据RNAi原理,酶切获得Lox目的片段,构建以除草剂Bar基因为筛选标记、种子特异性启动子P7αP启动SBA和Lox双干扰的pCAMBIA3301-SBA-Lox(pSBA-Lox)干扰表达载体,并通过农杆菌介导法转化大豆(品种为吉农28),采用PCR、Southern杂交和实时荧光定量PCR对转基因植株进行检测。【结果】质粒PCR和酶切鉴定结果表明,双价RNAi植物表达载体pSBA-Lox构建成功。将其转入到大豆中,对转化植株进行PCR、Southern杂交检测,结果显示,外源基因以单拷贝形式整合到植物基因组中,并能遗传给后代。T1代转基因植株的实时荧光定量PCR分析显示,转基因植株中SBA基因和Lox基因在籽粒中的表达量比未转化受体植株均明显降低,SBA基因表达量降低了35.9%~47.2%,Lox基因表达量降低了32.8%~56.1%,而在幼嫩叶片中的表达量相比对照植株变化不大。【结论】获得了大豆凝集素和脂肪氧化酶表达量均明显降低的T1代转基因大豆。     

运输中的机械损伤对贮藏初期苹果活性氧代谢的影响

通过测定红富士苹果运输损伤后的生理生化变化,发现机械损伤不仅使果实表面出现褐色斑块,果实呼吸强度迅速增加,而且细胞内促进活性氧产生的脂氧合酶的活性增加,果皮增加的幅度高于果肉;具有消除自由基作用的SOD和CAT的活性在损伤后也突然升高,但在损伤后第2～6天活性逐渐下降,同时,损伤后POD活性、MDA含量以及膜透性都有显著的增加,说明机械损伤破坏了膜的完整性、促进了脂质过氧化的产生,导致衰老性状的提前出现。本试验从理论上进一步证明减少运输中的机械损伤对延长贮藏寿命、提高果品品质具有重要的意义。     

大豆脂氧酶的热失活动力学与其二级结构的圆二色谱表现

应用大豆脂氧酶的变温圆二色谱图研究了大豆脂氧酶(LOX)的热失活与二级结构变化过程.结果表明:在50一65℃条件下,10 min内,LOX的酶活随热处理时间延长而下降,其热失活过程遵循一级动力学,活化能Ea值为217 kJ.mol-1.在相同的热处理条件下,LOX中二级结构a-螺旋和β-折叠的相对含量均在20%左右浮动...     

Lipolysis and Lipid Oxidation during Processing of Chinese Traditional Dry-Cured White Amur Bream (Parabramis pekinensis)

Lipolysis and lipid oxidation of intramuscular lipids during the dry-curing process of white amur bream (Parabramis pekinensis) were studied. All lipolytic enzyme activities decreased (p < 0.05) at the end of the process. The lipoxygenase activity increased during wet-salting (p < 0.05) and then decreased until the end of the process (p < 0.05). The daily variation of free fatty acids was correlated with those of the peroxide value (r = 0.976, p < 0.01) and thiobarbituric acid-reactive substances (r = 0.922, p < 0.01), respectively. These results suggest that lipolysis promotes lipid oxidation during the processing of dry-cured fish.     

厚朴酚对大鼠白细胞5-脂氧合酶活性和细胞内钙离子浓度的影响

目的：探讨厚朴酚对5—脂氧合酶活性的影响．以阐明其抗炎机理。方法：以大鼠胸腔白细胞为材料，分别用高效液相色谱法和荧光分光光谱法测定白三烯B4(LTB4)，5—羟二十碳四烯酸(5—HETE)的生成和细胞内钙离子水平。结果：厚朴酚对白细胞LTB4和5—HETE的生物合成有较强的抑制作用，其IC50值分别为8．5μmol/L和3．1μmol/L；厚朴酚还可以抑制趋化三肽(fMLP)刺激的白细胞内钙升高．但对静息状态的白细胞内钙离子水平没有明显的影响。结论：厚朴酚可以明显影响白细胞的功能，抑制炎性介质LTB4和5—HETE的生成，提示此功能与其抗炎作用机理有关。