抑制血管紧张素转化酶的中药及活性成分的研究

比较32味中药对血管紧张素转化酶（angiotensin converting enzyme,ACE）的抑制作用,并对枸杞的活性成分进行鉴别。高效液相色谱法（HPLC）评价药物对ACE活力的抑制作用,柱层析法对具有最强抑制作用的中药进行分离,确定活性最高的部位。32味中药提取物对ACE有不同程度的抑制作用,其中抑制作用最强的是枸杞,抑制率高达92.30%。枸杞提取物用D-101大孔树脂粗分,50%乙醇洗脱部位对ACE的抑制活性最强,此部位通过硅胶柱进一步纯化得到纯度更高的ACE抑制部位及活性成分。枸杞提取物对ACE酶有很强的抑制效果,大孔树脂和硅胶能很好的分离枸杞中对ACE有抑制作用的化合物。      

RP-HPLC测定保加利亚乳杆菌腺苷酸方法的建立与应用

建立适用于测定保加利亚乳杆菌腺苷酸的反相高效液相色谱方法,为评价代谢组学研究中淬灭液的淬灭效果提供方法支持。采用SinoChrom ODS-BPC18色谱柱,甲醇-30mmol/L磷酸钾（V/V=5∶95）缓冲液（pH7.0）作为流动相,流速0.7mL/min,柱温25℃,紫外检测波长254nm。结果表明该方法具有较好的线性和较高的精密度,回收率在94.12%～109.6%之间。利用该方法测定了使用最广泛的60%（v/v）冷甲醇/水溶液淬灭保加利亚乳杆菌的效果,结果发现ATP的泄露率高达70.43%±2.3%,能荷值是0.42±0.015,从而推断该淬灭方案不但会造成胞内代谢物的大量泄漏,而且菌体的代谢反应也没有完全停止,故该淬灭方案不适合保加利亚乳杆菌。      

樟子松树皮中松多酚的提取工艺研究及提取方法比较

对樟子松树皮中的松多酚进行提取,比较有机溶剂提取法、超声波辅助提取法和超声波-复合酶法对松多酚提取效果的影响。实验结果表明,有机溶剂提取法适宜工艺条件为:乙醇浓度为60%,料液比为1∶25（g/mL）,提取时间为4h,提取温度为60℃。超声波辅助提取法适宜工艺条件为:超声功率为300W,超声时间为2.5h,超声温度为60℃,溶液pH3.0。超声波-复合酶解提取法适宜提取工艺条件为:酶解时间为40min,酶解温度为45℃,加酶量为4%,酶解pH4.0。三种提取方法在最适工艺条件下松多酚得率分别为12.56、23.01、30.12mg/g。超声波-复合酶法提取时间短、提取效率高、提取效果好,超声波辅助提取法次之,二者提取效果均好于有机溶剂提取法。      

玫瑰红景天提取物rosavin抗疲劳作用的实验研究

目的:研究玫瑰红景天提取物rosavin对小鼠的抗疲劳作用。方法:实验分为对照组、rosavin低、中、高剂量组(60,180,360mg/kgmb)以及红景天苷阳性对照组(180mg/kgmb),对照组灌胃生理盐水,连续灌胃30d。分别测定小鼠力竭游泳时间,运动后肌乳酸、肝糖原、肌糖原和血清尿素氮含量。结果:与对照组比较,rosavin组的高、中、低剂量组均能延长小鼠力竭游泳时间(p<0.05),运动后肝糖原(p<0.05)、肌糖原含量高于对照组小鼠,肌乳酸浓度明显低于对照组(p<0.05)。与红景天苷阳性对照组比较,同等剂量下红景天苷抗疲劳效果略优于rosavin,rosavin高剂量组与红景天苷抗疲劳效果相当,两者差异没有显著性(p>0.05)。结论:rosavin有缓解体力疲劳的作用。      

紫花松果菊挥发油的油脂抗氧化作用研究

以过氧化值、酸值及TBA值为指标,以菜籽油和猪油为介质,并与人工合成抗氧化剂BHT和BHA进行对照,研究了紫花松果菊挥发油对菜籽油和猪油的抗氧化性能。结果表明:在所研究的浓度范围内,紫花松果菊挥发油对菜籽油和猪油均具有一定的抗氧化作用,且具有剂量效应关系。其中,添加量为2g/kg的紫花松果菊挥发油对菜籽油的抗氧化效果较为明显,几乎等效于0.2g/kgBHT和BHA的抗氧化作用。紫花松果菊挥发油对猪油的抗氧化效果则不及对菜籽油的抗氧化效果明显。      

椭球面弦支穹顶结构的稳定性

以上部网壳为椭球面的弦支穹顶结构为对象, 用ABAQUS软件建模, 考虑初始缺陷、布索方式及预应力水平等影响因素, 进行几何非线性及同时考虑几何非线性和材料非线性的稳定性分析, 分析时采用弧长法跟踪平衡路径, 得到不同参数下结构的荷载-位移曲线.通过对比分析各参数下荷载-位移曲线及稳定极限承载力, 椭球面弦支穹顶结构的稳定性能较单层网壳有了大幅度提高, 初始缺陷的存在降低了结构的稳定承载力.此外, 不同布索方式和预应力水平对结构的稳定承载力有较大的影响, 应进行优化设计.     

干燥方法对沙芥叶片品质的影响

研究自然干燥、真空干燥、鼓风干燥(40、60、80℃)3种干燥方法对沙芥干燥产品及复水后产品物理性质及营养成分的影响。结果表明:不同干燥方法处理的沙芥叶的物理性质及营养成分与鲜叶有较大差异,在物理性质方面,真空干燥叶片复水率显著高于其它处理(p<0.05);在营养成分方面,真空干燥条件下沙芥叶片与其复水后叶片的游离氨基酸、VC、可溶性蛋白含量均高于其它干燥方法。综上所述,真空干燥对沙芥叶片营养成分的破坏最小,复水性好而且干燥时间较短,是一种较好的沙芥叶片干制品的制备方法。      

Human β-Defensin 3 Inhibits Porphyromonas Gingivalis Lipopolysaccharide-Induced Oxidative and Inflammatory Responses of Microglia by Suppression of Cathepsins B and L

Recently, the effects of antibacterial peptides are suggested to have therapeutic potential in Alzheimer’s disease. Furthermore, systemic treatment of Porphyromonas gingivalis (Pg) lipopolysaccharide (LPS) induced Alzheimer’s disease-like neuropathological changes in middle-aged mice. Then, we examined whether human β-defensins (hBDs), antimicrobial peptides produced by the oral mucosa and salivary glands, can suppress Pg LPS-induced oxidative and inflammatory responses by microglia. hBD3 (1 μM) significantly suppressed Pg LPS-induced production of nitric oxide and interleukin-6 (IL-6) by MG6 cells, a mouse microglial cell line. hBD3 (1 μM) also significantly inhibited Pg LPS-induced expression of IL-6 by HMC3 cells, a human microglial cell line. In contrast, neither hBD1, hBD2 nor hBD4 failed to inhibit their productions. Furthermore, hBD3 suppressed Pg LPS-induced p65 nuclear translocation through the IκBα degradation. Pg LPS-induced expression of IL-6 was significantly suppressed by E64d, a cysteine protease inhibitor, and CA-074Me, a known specific inhibitor for cathepsin B, but not by pepstatin A, an aspartic protease inhibitor. Interestingly, hBD3 significantly inhibited enzymatic activities of recombinant human cathepsins B and L, lysosomal cysteine proteases, and their intracellular activities in MG6 cells. Therefore, hBD3 suppressed oxidative and inflammatory responses of microglia through the inhibition of cathepsins B and L, which enzymatic activities are necessary for the NF-κB activation.     

Genome-Wide Identification and Expression Analysis of Fatty Acid Desaturase (FAD) Genes in Camelina sativa (L.) Crantz

Camelina sativa (L.) Crantz is an indispensable oilseed crop, and its seeds contain many unsaturated fatty acids. FAD (fatty acid desaturase) regulates the synthesis of unsaturated fatty acids. In this research, we performed CsFAD gene family analysis and identified 24 CsFAD genes in Camelina, which were unevenly distributed on 14 of the 19 total chromosomes. Phylogenetic analysis showed that CsFAD includes four subfamilies, supported by the conserved structures and motifs of CsFAD genes. In addition, we investigated the expression patterns of the FAD family in the different tissues of Camelina. We found that CsFAD family genes were all expressed in the stem, and CsFAD2-2 was highly expressed in the early stage of seed development. Moreover, during low temperature (4 °C) stress, we identified that the expression level of CsFAD2-2 significantly changed. By observing the transient expression of CsFAD2-2 in Arabidopsis protoplasts, we found that CsFAD2-2 was located on the nucleus. Through the detection and analysis of fatty acids, we prove that CsFAD2-2 is involved in the synthesis of linolenic acid (C18:3). In conclusion, we identified CsFAD2-2 through the phylogenetic analysis of the CsFAD gene family and further determined the fatty acid content to find that CsFAD2-2 is involved in fatty acid synthesis in Camelina.     

CRISPR/Cas9-Based Knock-Out of the PMR4 Gene Reduces Susceptibility to Late Blight in Two Tomato Cultivars

Phytophthora infestans, the causal agent of late blight (LB) in tomato (Solanum lycopersicum L.), is a devastating disease and a serious concern for plant productivity. The presence of susceptibility (S) genes in plants facilitates pathogen proliferation; thus, disabling these genes may help provide a broad-spectrum and durable type of tolerance/resistance. Previous studies on Arabidopsis and tomato have highlighted that knock-out mutants of the PMR4 susceptibility gene are tolerant to powdery mildew. Moreover, PMR4 knock-down in potato has been shown to confer tolerance to LB. To verify the same effect in tomato in the present study, a CRISPR–Cas9 vector containing four single guide RNAs (sgRNAs: sgRNA1, sgRNA6, sgRNA7, and sgRNA8), targeting as many SlPMR4 regions, was introduced via Agrobacterium-tumefaciens-mediated transformation into two widely grown Italian tomato cultivars: ‘San Marzano’ (SM) and ‘Oxheart’ (OX). Thirty-five plants (twenty-six SM and nine OX) were selected and screened to identify the CRISPR/Cas9-induced mutations. The different sgRNAs caused mutation frequencies ranging from 22.1 to 100% and alternatively precise insertions (sgRNA6) or deletions (sgRNA7, sgRNA1, and sgRNA8). Notably, sgRNA7 induced in seven SM genotypes a −7 bp deletion in the homozygous status, whereas sgRNA8 led to the production of fifteen SM genotypes with a biallelic mutation (−7 bp and −2 bp). Selected edited lines were inoculated with P. infestans, and four of them, fully knocked out at the PMR4 locus, showed reduced disease symptoms (reduction in susceptibility from 55 to 80%) compared to control plants. The four SM lines were sequenced using Illumina whole-genome sequencing for deeper characterization without exhibiting any evidence of mutations in the candidate off-target regions. Our results showed, for the first time, a reduced susceptibility to Phytophtora infestans in pmr4 tomato mutants confirming the role of KO PMR4 in providing broad-spectrum protection against pathogens.