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31.
Ribonuelease activity and its isozyme pattern of mung bean cotyledon segment were determined during dedifferentiation. The results showed that the activity of ribonuelease in the dedifferentiated tissue is higher than that of control, three new bands of isozyme appear during callus formation. Addition of cycloheximide (CHM) at 0 or 24 hours inhibits either the enzyme activity or the appearance of new bands. These facts indicate that the changes of ribanuelease are at translation level. 相似文献
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33.
Hao He Huifang Li Toyosi Akanji Shengli Niu Zhujun Luo Dongli Li Navindra P. Seeram Panpan Wu Hang Ma 《Journal of enzyme inhibition and medicinal chemistry》2021,36(1):1665
Oleanolic acid (OA) is a natural cosmeceutical compound with various skin beneficial activities including inhibitory effect on hyaluronidase but the anti-hyaluronidase activity and mechanisms of action of its synthetic analogues remain unclear. Herein, a series of OA derivatives were synthesised and evaluated for their inhibitory effects on hyaluronidase. Compared to OA, an induction of fluorinated (6c) and chlorinated (6g) indole moieties led to enhanced anti-hyaluronidase activity (IC50 = 80.3 vs. 9.97 and 9.57 µg/mL, respectively). Furthermore, spectroscopic and computational studies revealed that 6c and 6g can bind to hyaluronidase protein and alter its secondary structure leading to reduced enzyme activity. In addition, OA indole derivatives showed feasible skin permeability in a slightly acidic environment (pH = 6.5) and 6c exerted skin protective effect by reducing cellular reactive oxygen species in human skin keratinocytes. Findings from the current study support that OA indole derivatives are potential cosmeceuticals with anti-hyaluronidase activity. 相似文献
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35.
Binggang Ma Xiaoyu Duan Chao Ma Jianxin Niu Huping Zhang Lizhong Pan 《Plant Molecular Biology Reporter》2008,26(3):199-212
The presence of antibiotic-resistant genes in genetically engineered crops together with the target gene has generated a number
of environmental and consumer concerns. In order to alleviate public concerns over the safety of food derived from transgenic
crops, marker gene elimination is desirable. Marker-free transgenic tomato plants were obtained by using a salicylic-acid-regulated
Cre–loxP-mediated site-specific DNA recombination system in which the selectable marker neomycin phosphotransferase nptII and cre genes were flanked by two directly oriented loxP sites. Upon induction by salicylic acid, the cre gene produced a recombinase that eliminated sequences encoding nptII and cre genes, sandwiched by two loxP sites from the tomato genome. Regenerant plants with the Cre–loxP system were obtained by selection on kanamycin media and polymerase chain reaction (PCR) screening. Transgenic plants were
screened for excision by PCR using nptII, cre, and PR-1a promoter primers following treatment with salicylic acid. The footprint of the excision was determined by sequencing
the T-DNA borders after a perfect recombination event. The excision efficiency was 38.7%. A new plant transformation vector,
pBLNSC (Genbank accession number EU327497), was developed, containing six cloning sites and the self-excision system. This
provided an effective approach to eliminate the selectable marker gene from transgenic tomato, thus expediting public acceptance
of genetically modified tomato. 相似文献
36.
八肽胆囊收缩素对内毒素休克时海马损伤的影响及其机制初探 总被引:2,自引:0,他引:2
目的:观察八肽胆囊收缩素(CCK-8)对内毒素休克(ES)时海马损伤的影响,并探讨其可能的作用机制。方法:将日本大耳白兔经静脉注入内毒素的主要活性成分脂多糖(LPS,8mg/kg)复制ES模型。动物(32只)随机分为对照组、LPS组、CCK-8+LPS组和非特异性CCK受体拮抗剂丙谷胺(Pro)+LPS组(n=8)。监测平均动脉压(MAP)的变化,光、电镜观察海马的组织形态学改变,比色法检测海马NOS和SOD活性、N0和MDA含量的改变.用SD大鼠(12只,同上复制模型及分组)以免疫组织化学染色法观察海马iNOS和nNOS表达的变化。结果:与对照组相比,注入LPS后出现MAP显著而持续下降(P〈0.01);海马部位神经元损伤明显;iNOS和nNOS表达增强,NOS活性、NO和MDA含量显著升高(P〈0.05、P〈0.01和P〈0.01),SOD活性则降低(P〈0.01)。预先注入CCK-8可明显减轻上述变化,预先注入Pro则加剧以上变化。结论:CCK-8可减轻ES时脑内海马部位的损伤。其机制可能与其抗氧化作用和抑制NO的过量生成有关。 相似文献
37.
The stability and shapes of domains with different bending rigidities in lipid membranes are investigated. These domains can
be formed from the inclusion of an impurity in a lipid membrane or from the phase separation within the membrane. We show
that, for weak line tensions, surface tensions and finite spontaneous curvatures, an equilibrium phase of protruding circular
domains or striped domains may be obtained. We also predict a possible phase transition between the investigated morphologies. 相似文献
38.
甜杨低温响应microRNAs的克隆与分析 总被引:1,自引:0,他引:1
MicroRNAs (miRNAs)作为一类21碱基左右的非编码小RNAs,参与植物生长发育的调控,并在植物对生物与非生物胁迫的应答过程中发挥重要作用.本研究依据miRNA高度保守特点,利用已公布的毛果杨(Populus trichocarpa)基因组序列设计引物,从甜杨(Populus suaveolens)基因组中克隆获得了12个miRNA基因座序列.序列比对结果表明,这些miRNA基因均为毛果杨低温响应miRNA基因的同源序列.同时,以低温(0℃)处理0~48 h的甜杨幼苗为试材,通过半定量RT-PCR法对miRNA基因的成熟体序列在不同处理时间下的表达谱进行分析,结果显示,大多数miRNA成熟体序列在甜杨低温胁迫下的表达模式与其在毛果杨中的表达极为相似,由此可推测这些保守性miRNAs可能在甜杨和毛果杨两物种对低温胁迫的应答反应中发挥相似的功能,而miR168a、miR168b和miR475a在两物种间表达现象的差异,表明它们可能通过调控多种靶基因而发挥不同作用.本文结果将为进一步研究甜杨基因功能提供基础. 相似文献
39.
中国葡萄属植物叶片气孔特征的研究 总被引:15,自引:2,他引:15
对起源于中国的葡萄属(Vitis L.)20个种或变种叶片气孔特性进行了观察研究。结果表明:气孔纵径对葡萄属种的分类有较大的价值;气孔比密度(叶片上所有气孔复合体面积与叶片面积之比)与叶片大小呈极显著正相关;气孔密度与气孔纵径呈极显著负相关;所有观察种类的叶片气孔类型均为不规则型。 相似文献
40.