Construction and Partial Biological Characteristics Analysis of Listeriolysin S llsB Gene Deletion Strain

In order to analyze the effect of listeriolysin S (LLS) llsB gene deletion on the biological characteristics of Listeria monocytogenes (LM),this study used homologous recombination to construct the llsB gene deletion strain LM90-ΔllsB,and the biological characteristics of growth characteristics,median lethal dose (LD₅₀) and organ-borne bacteria were studied in healthy Kunming male mice at 8 weeks old and weighing 40 g±5 g.The llsB gene deletion strain was successfully constructed,and the deletion strain had good genetic stability through continuous passage to 20 generations in vitro.Based on its growth curve examination,we found that the growth rate of the mutant strain was slightly higher than that of the parent strain.The results of mice infection test showed that the LD₅₀ of the parent strain and the deletion strain were 10^6.17 and 10^6.50 CFU,respectively.Compared with the parent strain,the amount of bacteria load of the deletion strain in the liver and spleen of the mice was extremely significantly decreased (P<0.01),the results showed that the infection ability of the mutant strain on mice was obviously weakened.No Listeria monocytogenes was detected in the brain.The results suggested that llsB gene might have direct or indirect regulatory effect on some biological characteristics of LM90,and it would provide a theoretical basis for further understanding of the pathogenic mechanism of LLS,prevention and control of listeriosis.     

三种融合标签对大熊猫轮状病毒结构蛋白VP6-VP7可溶性表达的影响

大熊猫轮状病毒(giant panda rotavirus,GPRV)是引起幼龄大熊猫腹泻的主要病原,对圈养大熊猫产生了较大的危害。轮状病毒结构蛋白VP6是一种载体蛋白,可介导黏膜免疫反应。VP7是轮状病毒结构蛋白中主要的中和抗原。因此,VP6-VP7的融合表达作为候选抗原对该病的防治具有重要的意义。传统大肠埃希菌原核表达存在表达量低、可溶性差以及纯度低等弊端。本研究使用醛缩酶(EDA)、谷胱甘肽S-转移酶(GST)、麦芽糖结合蛋白(MBP)3种融合标签,以实现获得表达量高和纯度高的GPRV-VP6-VP7重组表达蛋白。将扩增的VP6、VP7基因片段利用同源重组酶构建到含3种融合标签的表达载体pET21b上,将重组质粒转化至大肠埃希菌Rosetta(DE3)感受态细胞中进行低温诱导表达。用Ni-柱亲和层析法纯化目的蛋白,SDS-PAGE和Image J分析蛋白表达量和可溶性,Western blot分析得到表达的重组表达蛋白正确且具有蛋白活性。实验结果证明,EDA标签能显著促进VP6-VP7蛋白的原核可溶性表达,提高VP6-VP7蛋白表达量。     

旱地燕麦间作对土壤酶活性、微生物含量及产量的影响

本文通过研究内蒙古旱作区禾本科、豆科及茄科间作对土壤生物性状的影响，旨在揭示燕麦（Avena sativa Linn）与不同作物间作及其单作在土壤酶活性、微生物量及土地当量比（LER）等方面的优势机理。本试验设置燕麦、黑豆（Glycinemax（L.）merr）、苜蓿（Medicago sativa）、马铃薯（Solanum tuberosum L）单作和黑豆间作燕麦、苜蓿间作燕麦、马铃薯间作燕麦共7个处理，探讨各处理对上述各指标的影响。结果表明：燕麦间作黑豆土地当量比最高，2015年和2016年分别为1.62和1.65。燕麦间作黑豆土壤脲酶活性和蔗糖酶活性较苜蓿间作燕麦、马铃薯间作燕麦显著提高了5.00%~51.61%和5.73%~52.29%。2015年和2016年播种后75 d苜蓿间作燕麦土壤过氧化氢酶活性显著高于黑豆间作燕麦，分别提高了29.47%和40.56%。黑豆间作燕麦对比其他两间作处理土壤微生物的生物量碳、氮含量分别显著提高了2.70%~17.89%和11.36%~26.47%，土壤脲酶活性提高了1.51%~55.22%，蔗糖酶活性提高了5.73%~52.29%，是该地区最优的间作模式。     

PPARγ mediates effects of diosgenin on proliferation and apoptosis in human glioblastoma U87MG cells

AIM:To investigate the effect of diosgenin (Dio) on the proliferation, apoptosis and expression of peroxisome proliferator-activated receptor γ (PPARγ) in human glioblastoma U87MG cells and its possible mechanism. METHODS:Human astrocytes (HA) and U87MG cells were cultured in vitro and treated with Dio (0, 10, 20, 30, 40 and 50 μmol/L) and GW9662 (5 μmol/L) for 48 h, and then the cell viability was detected by CCK-8 assay. Cell colony formation assay was used to assess the proliferation potential. Flow cytometry was used to analyze the cell cycle distribution and apoptosis. The mRNA expression level of PPARγ was measured by RT-PCR. Western blot was used to determine the protein levels of PPARγ, cyclin D1, cyclin E1, Bcl-2 and Bax. RESULTS:Dio had no significant influence on the viabi-lity of HA (P>0.05). However, Dio remarkably reduced the viability of U87MG cells in a dose-dependent manner (P<0.05) with IC₅₀ of 24.31 μmol/L. Meanwhile, Dio remarkably diminished colony formation ability (P<0.05), induced G₀/G₁ phase arrest of the cell cycle and apoptosis (P<0.05), up-regulated the expression of PPARγ at mRNA and protein levels, increased the protein level of Bax (P<0.05), and down-regulated the protein levels of cyclin D1, cyclin E1 and Bcl-2 (P<0.05) in a dose-dependent manner. However, these effects induced by Dio were inhibited by GW9662 (P<0.05), a specific inhibitor of PPARγ. CONCLUSION:Dio may inhibit proliferation and induce apoptosis in human glioblastoma U87MG cells most likely via up-regulating the expression of PPARγ, and then down-regulating the protein levels of cyclin D1, cyclin E1 and Bcl-2, and up-regulating the protein level of Bax.     

12种杀虫剂对日本通草蛉不同虫态的毒力及安全性评价

为明确常见杀虫剂对日本通草蛉各虫态的影响,在室内分别采用浸渍法和喷雾法测定了12种(8类)杀虫剂对日本通草蛉卵、幼虫、蛹和成虫的毒性,并评价了杀虫剂对日本通草蛉的毒性风险。结果表明,高效氯氰菊酯对日本通草蛉为极高风险,毒死蜱、吡虫啉、烯啶虫胺和阿维菌素为高风险,溴氰虫酰胺、啶虫脒和氯虫苯甲酰胺为中等风险,噻嗪酮、吡蚜酮、螺虫乙酯和甲氧虫酰肼为低风险;与其他虫态相比,12种杀虫剂对日本通草蛉蛹的毒性均为最低。在害虫生物防治及综合治理中应尽量选用对日本通草蛉毒性低的杀虫剂,以起到保护天敌的作用。     

茶树新品种--梦茗

"梦茗"系从安徽省岳西县来榜镇优良地方群体种中采用单株选育法育成的适制绿茶新品种。经安徽省内品比、推广示范和全国区试,发现"梦茗"物候期与福鼎大白茶相当,属早生种。品质优异,全国区试3个点感官审评总分均高于对照;内含物含量高,氨基酸含量4.9%、茶多酚总量26.9%、水浸出物总量40%。产量高,品比试验高于福鼎大白茶26.45%,全国区试产量与对照相当。抗旱能力强,抗寒能力与对照相当。     

“金花散茶”及“金花菌粉”对被动吸烟小鼠肺组织JAK2/STAT3炎性及磷酸化蛋白表达的影响

为探究“金花散茶”及其“金花菌粉”对被动吸烟(Cigarette smoking environment,CSE)小鼠肺组织受损的预防及修复机制,建立C57BL/6小鼠CSE模型,以600 mg∙kg^-1剂量的金花散茶茶汤(Eurotium cristatum tea extract,ECTE)及金花菌粉浸提液(Eurotium cristatum powder extract,ECPE)进行灌喂处理。与CSE模型组相比,小鼠灌喂ECPE和ECTE后,肺组织病理学切片显示其可保护小鼠肺组织形态结构完整;酶联免疫分析显示,灌喂ECPE和ECTE可显著抑制小鼠血清IL-6、IL-8、IL-1β、IFN-γ和TNF-α表达量上调;Western blot结果表明,灌喂ECPE和ECTE对小鼠肺组织p-JAK2、p-STAT3、p-JAK2/JAK2、p-STAT3/STAT3高表达起到抑制作用。以上研究结果表明,灌喂ECPE、ECTE对CSE肺受损小鼠具有明显保护作用,总体趋势为ECPE组优于ECTE组、预防组优于治疗组。     

伐地那非增加EGCG-β-乳球蛋白纳米粒对肝癌细胞的抑制作用

较高浓度的EGCG才能抑制癌细胞的增殖,通过纳米化和EGCG与其他药物的联合使用是提高EGCG生物活性的重要策略。本研究将EGCG和伐地那非（VD）同时包埋于β-乳球蛋白（β-Lg）纳米载体中,制备出EGCG-VD-β-Lg纳米粒（EVβ-NPs）,体外试验证实,EVβ-NPs能提高人肝癌细胞（HepG2细胞）中Caspase-3活性,使HepG2细胞在S期产生明显的阻滞,诱发细胞核分裂,从而导致HepG2细胞凋亡。研究结果表明,将EGCG与微量的VD联合使用,并通过纳米化包埋可以显著提高EGCG的抗癌活性。这一方法在EGCG抗癌制品的开发方面具有潜在的价值。