分光光度法测定脯氨酸的含量

文章用分光光度法研究了脯氨酸与四氯对苯醌的荷移反应 .实验指出 ,在硼砂缓冲溶液中 ,脯氨酸与四氯对苯醌于 30℃的水浴中恒温 1 2 0 min,可形成 1∶ 1的稳定络合物 ,其λmax=35 8nm,表观摩尔吸光系数 ε=1 .5 0× 1 0 5L·mol- 1 ·cm- 1 ,在 60 ng·m L- 1 ～ 40 0 ng·m L- 1 的范围内符合比耳定律 ,用本方法测定药物制剂的含量与文献方法一致 ,回收率在 99.65 %～ 1 0 0 .7%范围内 ,相对标准偏差在 1 .4%以内 .     

L-脯氨酸发酵液的预处理

本文用絮凝技术对L-脯氨酸发酵液进行了预处理,筛选得无机聚凝剂投加量为3.75%,有机絮凝剂量为5ppm,在pH为6.5,40℃下保温20分时絮凝效果最佳,能很好地改善过滤性能,提高发酵液的固液分离效果,并使树脂对L-脯氨酸的重量吸附容量增加40%。通过滤饼的重量比阻和溶液流动电位的测定分析,从理论上进一步证实了所筛选到的絮凝条件的合理性。     

NaCl对拟南芥(Arabidopsis thaliana)生长与渗透调节的影响

对与拟南芥耐盐性相关的某些生理指标进行了研究。结果发现,随着盐浓度的增加,拟南芥的质膜透性增加,MDA含量、脯氨酸含量、可溶性糖含量、有机酸含量、游离氨基酸含量、根冠比、钠离子含量均增加,而渗透势、钾离子含量、干鲜重、含水量则下降。这表明,随着盐胁迫的加重,一方面拟南芥受到的伤害加重,另一方面植株通过合成脯氨酸、可溶性糖等渗透调节物质,增大根冠比以提高吸水能力等抗逆机制,以应对胁迫,提高耐盐性。     

丝瓜幼苗的吸水规律

以葫芦科1年生攀缓植物丝瓜幼苗为材料,研究了它在低浓度不同种类盐中的吸水规律和在不同浓度的KCl溶液中以总吸水倍率和叶子中脯氨酸质量分数以及培养外液渗透压变化作为测定指标,从渗透压作为丝瓜幼苗时期吸水动力的角度,探讨其吸水动力学变化及生长规律.结果表明:低浓度(0.001 0 mol/L)各种盐对丝瓜幼苗的总吸水倍率的影响为LiCl＞KCl》二次蒸馏水＞NaCl;不同浓度(0～0.014 0 mol/L)KCl影响下丝瓜幼苗总吸水倍率、脯氨酸质量分数、培养液进入植物体内的粒子数随KCl浓度成峰形变化,并且三者的变化基本吻合.KCl浓度为0.001 0 mol/L时脯氨酸质量分数达最低值,0.004 0 mol/L时脯氨酸的质量分数达最高值,在无盐和高盐环境下脯氨酸的大量积累是植物细胞的适应性反应,其质量分数的高低不宜作为丝瓜的抗盐性指标.脯氨酸质量分数与进入植物体内粒子数变化正相关,并拟合出关系式w=k0+keR0n,w为脯氨酸的质量分数,n为进入植物体内的粒子数,k0,k,R0均为常数.本研究为探讨植物体中脯氨酸积累的生理作用及意义提供参考.     

Structural characterization of two papaya chitinases, a family GH19 of glycosyl hydrolases

Two chitinases, able to use tetra-N-acetylglucosamine, chitin and chitosan as substrates, were characterized after purification from Carica papaya latex. The complete amino acid sequence of the major form and about 40% of the minor one were determined through proteolytic digestions and mass spectroscopy analysis. Sequencing demonstrated that both papaya chitinases are members of the family 19 of glycosyl hydrolases (GH19). Based on the known 3-D structures of other members of family GH19, it was expected that papaya chitinases would adopt all-alpha structures. However, circular dichroism and infrared spectroscopy indicated, for the papaya chitinases, a content of 15–20% of extended structures besides the expected 40% of alpha helices. Since the fully sequenced papaya chitinase contains a large number of proline residues the possibility that papaya chitinase contains polyproline II stretches was examined in the context of their resistance against proteolytic degradation. Received 11 July 2006; received after revision 13 October 2006; accepted 25 October 2006     

盐地碱蓬Δ~1-二氢吡咯-5-羧酸合成酶基因(SsP5CS)的克隆及表达特性

从盐地碱蓬 (Suaedasalsa)中克隆了Δ1 -二氢吡咯 -5 -羧酸合成酶基因的cDNA片段 (S .salsaΔ1 -pyrroline -5 -carboxylatesynthasegene,Ssp5CS) .Southern杂交表明SsP5CS基因在盐地碱蓬基因组中只有一个拷贝 ;Northern杂交结果表明 ,不同盐处理 (4 0 0mmol/LNaCl)时间下SsP5CS在盐地碱蓬叶中的表达量明显增加 ;同时盐胁迫条件下盐地碱蓬叶中的脯氨酸含量与对照相比显著的增加 ,并且其渗透调节能力也逐渐增强 .推测SsP5CS基因可能在保护盐地碱蓬免受盐胁迫损伤的过程中起到重要作用     

外源激素脱落酸对小麦幼苗脯氨酸含量的影响

用外源激素脱落酸处理小麦幼苗,结果发现小麦幼苗体内的脯氨酸含量不仅随着外源脱落酸的浓度增大而增加,而且在处理的48小时内,随处理时间的延长,脯氨酸含量持续增加,处理48小时后,幼苗体内脯氨酸含量开始减少,表明脱落酸能促进脯氨酸的合成,抑制脯氨酸的分解。     

Response of the accumulation of proline in the bodies of<Emphasis Type="Italic">Populus euphratica</Emphasis> to the change of groundwater level at the lower reaches of Tarim River

The content of proline in the plant bodies is closely related to the converse-succession-resistant capability of plants. Under the drought stress, the proline accumulates rapidly in the plant bodies for maintaining a certain mois-ture content and an expanding-pressure momentum in cells through the osmoregulation, thus the drought-resis- tant capability and the converse-succession-resistant ca-pability of plants are increased[1,2]. Many researches on the relationship between the proline and the…     

不同抗旱品种胡麻苗中脯氨酸累积的差异

在干旱胁迫下，胡麻旱地品种８１１１５１和水地品种８６Ⅲ２３累积较多的脯氨酸，分别比对照增加６倍和４倍．旱地品种的累积量为水地品种的２倍，达８．０７３ｍｇ·ｇ－１（ＤＷ），二者在干旱胁迫下脯氨酸累积量差异ｔ检验达极显著水平