三孢布拉霉crgA启动子的克隆和活性分析

【背景】CrgA是三孢布拉霉(Blakesleatrispora,Bt)中调控类胡萝卜素合成的关键负调控因子,其表达水平会影响类胡萝卜素的合成。【目的】克隆三孢布拉霉crgA启动子并分析其活性,为进一步解析CrgA表达调控机制奠定基础。【方法】通过综合微生物基因组(integrated microbial genomes, IMG)数据库提供的基因组序列,克隆crgA翻译起始位点上游2 000 bp序列,分析其顺式调控元件和转录起始区域预测,通过RT-qPCR分析不同光照时间对三孢布拉霉crgA相对转录水平的影响;构建4个不同长度的crgA启动子截短序列驱动的GUS-mGFP5重组表达载体p1303-procrgAF、F1、F2和F3,利用农杆菌侵染整合到三孢布拉霉基因组中,在黑暗和光照条件下测定β-D-葡萄糖苷酸酶(β-D-glucuronidase,GUS)酶活性并观察荧光信号。【结果】crgA启动子不仅包含基础的TATA-box和CAAT-box元件,还包括多个与光响应相关的元件。观察荧光结果显示CaMV35S和构建的4个突变启动子均能在三孢布拉霉体内驱动下游基因表达,检测GUS...     

非洲猪瘟病毒I226R蛋白抑制cGAS-STING通路介导的天然免疫应答

本研究旨在探究非洲猪瘟病毒(African swine fever virus, ASFV) I226R蛋白(I226R protein, pI226R)抑制cGAS-STING信号通路的作用机制。利用双荧光素酶报告系统和实时荧光定量PCR (real-time quantitative PCR, qPCR)证明pI226R显著抑制cGAS-STING通路介导的I型干扰素及干扰素刺激相关基因的产生。免疫共沉淀及激光共聚焦显微镜试验发现pI226R与cGAS蛋白相互作用。免疫印迹分析证明pI226R通过自噬-溶酶体途径促进cGAS蛋白的降解。同时,pI226R阻碍了cGAS与E3泛素连接酶三基序蛋白56 (tripartite motif protein 56, TRIM56)的结合,导致cGAS的单泛素化减弱,从而抑制了cGAS的活化和cGAS-STING通路的激活。总之,本研究证明ASFV pI226R通过拮抗cGAS进而抑制宿主的抗病毒天然免疫反应,进一步增加了对研究ASFV免疫逃逸机制的理解,为疫苗的研发提供了理论基础。     

盐磷胁迫对木麻黄和台湾相思种子萌发及幼苗生长的影响

恶劣环境下,人工海防林因面临养分胁迫而经营困难。为探讨盐、磷胁迫对主要海防林树种木麻黄和台湾相思种子萌发及生长的影响,该研究分别用不同浓度的NaCl(盐)和KH₂PO₄(磷)溶液处理种子和浇灌幼苗,测定种子萌发和幼苗生长指标。结果表明：(1)高盐胁迫显著抑制种子萌发,对幼苗生长有一定影响,但两种植物影响程度不同;台湾相思种子萌发耐盐性高于木麻黄,前者相对盐害率最大值为23.03%,后者为89.15%;随着盐浓度增加,木麻黄和台湾相思种子的发芽率、发芽势、发芽指数和活力指数均降低,对应最大值分别为38.70%、34.67%、18.70、0.055和76.67%、62.22%、48.46、6.11。(2)两种植物的株高和根长随盐浓度增加而降低,木麻黄和台湾相思株高分别为12.29～6.01 mm和48.27～17.33 mm,根长分别为8.57～1.45 mm和33.41～5.88 mm;台湾相思根、茎、叶生物量及根冠比均随盐浓度的增加逐渐减小,木麻黄各处理差异较小。(3)台湾相思的种子和幼苗较木麻黄更耐低磷环境,二者最适磷浓度存在差异;木麻黄种...     

油茶籽饼抗真菌活性成分的研究

从油茶籽饼中已经分离得到一种新的抗真菌活性成分油茶皂甙A,被鉴定为齐墩果烷型的五环三萜皂甙,它的mp为258～260℃,[α]_D~(27)=-20°(C=1％,80％EtOH),体外试验研究表明油茶皂甙A有较强的抑制真菌作用,对红包毛癣菌、石膏样癣菌、断发癣菌、黄癣菌、紫色癣菌、絮状表皮癣菌的MIC为0.125～1.000mg/ml,对白色念珠菌的MIC为0.0625～0.2500mg/ml。     

急性髓系白血病mRNA与非编码RNA差异表达谱及CeRNA调控网络分析

利用GEO数据库(gene expression omnibus database)通过生物信息学分析方法探讨急性髓系白血病(acute myelogenous leukemia,AML)的发病机制。检索GEO数据库中AML相关芯片数据集GSE142698、GSE142699和GSE96535。利用GEO2R分析得到差异mRNAs、miRNAs以及差异lncRNAs。利用在线生物信息学分析工具DAVID对差异mRNAs进行GO富集分析和KEGG通路分析。利用miRWalk数据库预测AML相关miRNAs的靶向mRNAs,利用Spongescan数据库预测AML相关miRNAs的靶向lncRNAs,构建lncRNA-miRNA-mRNA竞争性内源RNA （competing endogenous RNA,ceRNA）调控网络。共筛选出29个显著差异mRNAs、70个显著差异miRNAs和20 005个显著差异lncRNAs。GO富集分析和KEGG通路分析显示,差异表达基因主要涉及蛋白磷酸化、细胞分裂、细胞增殖的负调控、基因表达的正向调节、周期蛋白依赖的丝氨酸/苏氨酸激酶活性的调节等生物过程以及细胞周期、细胞衰老、癌症通路、PI3K-Akt通路等信号通路。将miRWalk数据库预测的靶向mRNAs与差异mRNAs取交集,Spongescan数据库预测的靶向lncRNAs与差异lncRNAs取交集,分别确定了25个mRNAs、6个lncRNAs参与AML相关ceRNA调控网络的构建。结果表明,lncRNAs可能作为关键的ceRNA,通过调控miRNA和相关靶基因参与AML的发生与发展,研究结果为AML诊断和治疗的分子生物学研究提供了新的依据。     

鼠兔核质杂交胚胎早期发育的研究

细胞核移植技术已被证明是研究发育中核质相互关系的非常重要的手段之一,电融合技术也是近十年发展起来的新型细胞融合技术。本实验运用这两项技术,进行了鼠、兔目间核质杂交实验,小鼠8-细胞核在激活的兔去核卵母细胞中,发生了染色体超前凝聚及核膨胀,融合卵移植到小鼠输卵管4.5天后,冲洗出,有5.4%的重构卵发育到囊胚期,通过染色体检查,囊胚细胞中均为小鼠染色体,其中一个囊胚为正常小鼠核型(2 n=40,XX)。通过本实验,我们认为:鼠兔远缘核质杂交胚胎的早期发育是可能的。     

Insecticidal and Repellent Effects of the Essential Oils Extract from Zanthoxylum myriacanthum against Three Storage Pests

The co-storage of two or more Chinese herbal medicines can effectively prevent the herbs from the damage by pests. Thus, it is important to protect herbs and crops to study Chinese herbal medicines and their medicinal components against storage pests. This study aimed to assess the insecticidal activities and repellent effect of essential oils (EOs) extracted from fruits at different periods from Zanthoxylum myriacanthum Wall. ex Hook. f. (1 h, 2 h, 3–5 h and 5–7 h), and their major compounds against three kinds of pests (Tribolium castaneum, Lasioderma serricorne, and Liposcelis bostrychophila). The results of gas chromatography-mass spectrometer analysis revealed homomyrtenol (22.56 %, 28.01 %, 28.48 % and 28.41 %, respectively) and p-cymene (30.58 %, 13.95 %, 24.97 % and 6.85 %, respectively) were the common major compounds of the EOs at 1 h, 2 h, 3–5 h, and 5–7 h. m-Cymene contents in EOs of fruits, 1 h, 2 h and 3–5 h were 3.85 %, 0.95 %, 6.71 %, and 6.15 %, respectively. According to Principal component analysis (PCA), the composition of fruits′ EO was significantly different from other EOs due to the different collection times. The bio-assays showed that EOs and major compounds were toxic to all three pests, but the fumigation effect on L. bostrychophila was not noticeable. EOs extracted at different times had a repellent effect on the three pests at the highest concentration (78.63 nL/cm²), but the attractive effects of the EOs of 3–5 h, 5–7 h, and p-cymene were observed at the low concentrations (3.15, 0.63 and 0.13 nL/cm²). Our results suggest that Z. myriacanthum have the potential to be developed as biological insecticides.     

Quality Assessment of Bee Pollen-Honey Mixtures Using Thin-Layer Chromatography in Combination with Chemometrics

The aim of this study is to develop a rapid, effect-directed screening method for quality assessment of bee pollen-honey mixtures. The comparative antioxidant potential and phenolic content of honey, bee pollen, and the bee pollen-honey mixtures, was performed using spectrophotometry. The total phenolic content and antioxidative activity of bee pollen-honey mixtures with 20 % bee pollen share were in the range 3.03–3.11 mg GAE/g, and 6.02–6.96 mmol TE/kg, respectively, while mixtures with 30 % bee pollen share contained 3.92–4.18 mg GAE/g, and 9.69–10.11 mmol TE/kg. Chromatographic fingerprint of bee pollen-honey mixtures was performed by high-performance thin-layer chromatography with conditions developed by authors and reported for the first time. Fingerprint analysis hyphenated with chemometrics enabled authenticity assessments of honey in mixtures. Results indicate that bee pollen-honey mixtures represent a food with highly, both, nutritious characteristics and health-promoting effect.     

草菇子实体多肽提取工艺及其抗氧化活性

为了优化草菇子实体多肽的提取工艺和探究其抗氧化活性,以草菇子实体为原料,采用酶解法提取草菇子实体多肽,通过单因素试验得出最佳的酶解工艺,并使用Box-Behnken设计试验组合。结果表明：草菇子实体提取多肽的最佳工艺为料液比1:52 (g/mL)、加酶量7 200 U/g、酶解温度43 ℃,此工艺条件下的多肽得率为67.76%。从1,1-二苯基-2-三硝基苯肼(DPPH)自由基清除能力、铁离子还原能力、超氧阴离子自由基清除能力和羟自由基清除能力4个方面研究其体外抗氧化能力,结果表明,草菇子实体多肽对DPPH自由基清除率为74.11%,超氧阴离子自由基和羟自由基清除率分别在69.64%和91.83%达到稳定,草菇子实体多肽还具有一定的还原力,说明草菇子实体多肽可以作为优质抗氧化肽的良好来源。该研究为草菇多肽的高效制备和抗氧化肽等高附加值产品的研发提供理论依据。