航天搭载与NaN3处理对甘蓝型油菜根尖细胞的诱变效应

 【目的】观察太空辐射和叠氮化钠对甘蓝型油菜诱变当代（M1）根尖细胞的细胞学效应。【方法】利用中国“实践八号”卫星搭载和叠氮化钠（NaN3）对甘蓝型油菜种子进行诱变处理,观察处理后根尖细胞的有丝分裂指数、染色体畸变率及微核率的变化。【结果】航天搭载促进有丝分裂,复合处理同航天搭载相比,甘蓝型油菜种子的根尖细胞对有丝分裂有抑制效应。同时,复合处理与两个单处理相比,可使多数甘蓝型油菜产生较高频率的染色体畸变。各处理均能诱导油菜根尖细胞产生较高频率的微核,且以航天诱变产生的最多。NaN3在一定程度上降低了甘蓝型油菜种子经空间搭载后的染色体畸变和细胞微核率,促进了空间诱变损伤修复。【结论】卫星搭载与NaN3处理都使甘蓝型油菜在细胞学水平上发生了真实的诱变效应;不育系与其相应保持系表现出一致的诱变效果。     

库车坳陷克深地区现今地应力场及储层裂缝数值模拟

克深三维区目前处于勘探开发的前期,需要明确地应力场及地下储层裂缝的分布规律,指导开发工作,但该区存在地层埋深大、取心困难、成像测井资料缺乏等实际情况,应力场研究及裂缝预测难度大。利用有限元分析方法,以井点现今地应力值为约束进行了克深三维区现今地应力场的数值模拟,同时建立了应力应变与裂缝参数的定量关系模型,利用古今应力场结合法对克深三维区的裂缝参数进行了预测,模拟结果显示构造高部位和断层带是低应力值区及裂缝的有利发育区。裂缝的数值模拟结果与测井解释结果对比表明,预测结果与实钻吻合度较高,裂缝预测效果较好。     

表达鹅细小病毒VP3基因重组腺病毒的构建与鉴定

[目的]构建表达鹅细小病毒 （GPV） VP3基因的重组腺病毒,为机体免疫试验和免疫效果评价奠定基础.[方法]以重组质粒pcDNA-VP3为模板,以GPV-VP3为目的基因,构建GPV-VP3重组腺病毒载体,通过转染获得能稳定表达GPV-VP3基因的重组腺病毒,通过IFA和Western-blot检测GPV-VP3基因的表达情况.[结果]扩增到的GPV-VP3基因全长为1 605 bp,线性化的重组腺病毒穿梭质粒pCR259-VP3能在QBI-HEK293细胞中瞬时表达GPV-VP3基因,表达蛋白的分子量约为60Ku.[结论]该重组腺病毒的构建将为GPV新型疫苗研发和后期体内试验奠定基础.     

葡萄SCARECROW Like 14-Like基因的表达特征及胁迫响应研究

为探索外源赤霉素(GA3)介导的无核葡萄果实膨大过程中的信号途径的调控基因,寻找验证主要调控元件,本研究以欧亚种无核葡萄品种‘无核白鸡心’(Vitis vinifera L.cv.Centennial Seedless)为材料,通过半定量RT-PCR技术分析属于GRAS基因家族的SCARECROW Like 14-Like(VvSCL14-Like)基因在葡萄不同组织器官和果实发育期的表达。通过启动子克隆、生物信息学分析、promoter∷GUS融合基因和GUS组织染色法对该基因的表达特征进行了研究。半定量RT-PCR结果表明,VvSCL14-Like基因主要在休眠芽中表达,在果实发育过程中无表达。利用GA3对葡萄幼果进行膨大处理,处理后1、3和7d的果实转录组结果表明VvSCL14-Like的转录水平无差异。对VvSCL14-Like启动子进行生物信息学分析,发现多个响应外源激素和逆境胁迫的作用元件。VvSCL14-Like启动子驱动的GUS基因,只在拟南芥萌发初期下胚轴处表达。以GA3和NaCl分别处理阳性拟南芥幼苗,48h后GUS基因均在叶柄和叶脉表达。干旱胁迫处理阳性拟南芥幼苗,15d后GUS基因只发现在根部表达。研究结果表明:VvSCL14-Like基因的表达具有组织特异性,参与外源赤霉素(GA3)和非生物胁迫响应过程,但不是外源赤霉素(GA3)介导的无核葡萄果实膨大过程的主要调控元件。     

Anticancer Alkaloid Lamellarins Inhibit Protein Kinases

Lamellarins, a family of hexacyclic pyrrole alkaloids originally isolated from marine invertebrates, display promising anti-tumor activity. They induce apoptotic cell death through multi-target mechanisms, including inhibition of topoisomerase I, interaction with DNA and direct effects on mitochondria. We here report that lamellarins inhibit several protein kinases relevant to cancer such as cyclin-dependent kinases, dual-specificity tyrosine phosphorylation activated kinase 1A, casein kinase 1, glycogen synthase kinase-3 and PIM-1. A good correlation is observed between the effects of lamellarins on protein kinases and their action on cell death, suggesting that inhibition of specific kinases may contribute to the cytotoxicity of lamellarins. Structure/activity relationship suggests several paths for the optimization of lamellarins as kinase inhibitors.     

Studies on the macromolecular components of nonwood available in Bangladesh

The structural feature of macromolecular component of dhaincha, cotton stalks, jute fiber, rice straw and wheat straw, which are commonly used in paper pulp production in forest deficient countries, was thoroughly studied. Lignin was isolated by classical Bjorkman method and characterized by elemental and methoxyl analysis, alkaline nitrobenzene oxidation, FTIR and ¹H NMR spectroscopy. The C₉ formulas for cotton stalks, jute fiber, dhaincha, rice straw and wheat straw were C₉H_8.95O_3.53(OCH₃)_1.00, C₉H_8.12O_4.03(OCH₃)_1.65, C₉H_8.10O_4.65(OCH₃)_1.32, C₉H_8.58O_3.74(OCH₃)_1.23 and C₉H_8.31O_3.54(OCH₃)_1.23, respectively. The alkaline nitrobenzene oxidation products showed that syringyl to vanilin ratio of these nonwood varied from 1.1 to 2.9. Jute fiber showed the highest syringyl to vanilin ratio that are consistent with C₉ formula. The β-O-4 units in these nonwood lignins had predominately erythro stereochemistry type. The crystalline structure of these nonwood cellulose was also studied using X-ray diffraction and FTIR spectroscopy. The proportions of crystallinity, crystal size were varied from plant to plant. Jute fiber showed the highest proportion of crystallinity (73.4%) and crystal size (4.2 nm). The degree of polymerization of these nonwoods cellulose has also been studied. Degree of polymerization of jute cellulose was also the highest (3875). FTIR spectroscopy showed that these nonwoods cellulose was monoclinic unit cell structure (I_β). Carbohydrate analysis showed that the main sugar component in the hydrolyzates of these nonwoods were xylose apart from glucose.     

不同浓度铝离子对玉米根芽幼苗的影响

用20、40、60、80 mg/L浓度铝离子的培养液处理玉米幼苗12 d,研究酸性条件下不同浓度铝离子(Al3+)对玉米根芽生长的影响。结果表明,Al3+对玉米根芽生长有显著抑制作用,且随着浓度的升高抑制作用显著加强;对于根的生长,Al3+浓度有一个相对促进其生长的浓度(20 mg/L)。20 mg/L培养液处理对植株无明显影响;40 mg/L培养液处理对植株生长有显著抑制作用,对根部的作用尤为明显。随Al3+浓度的升高,含水量降低,Al3+浓度与植株地上部分含水量、根含水量呈极显著相关。     

PA-X基因的长度变化对H3N2犬流感病毒复制能力和致病性的影响

H3N2犬流感病毒(canine influenza virus, CIV)已在中国多地的犬群中流行,是禽流感跨宿主感染并形成新分支的近期案例。研究表明,PA-X基因与甲型流感病毒适应新宿主的能力相关,且其长度能够影响甲型流感病毒的复制及致病能力。为了解PA-X基因的长度变化对H3N2 CIV复制能力及致病力的影响,本研究利用H3N2 CIV的8质粒操作系统,拯救了三株重组H3N2 CIV毒株：PA-X基因表达大小为232个氨基酸多肽的亲本病毒CIV＿PA-X＿232;对PA编码区第191、192位氨基酸的密码子进行改造,PA-X基因不表达蛋白的重组病毒CIV＿PA-X＿Knock;对PA+1编码区第232位氨基酸进行突变,PA-X基因表达大小为252个氨基酸多肽的重组病毒CIV＿PA-X＿252。通过比较3株重组病毒的聚合酶活性,在MDCK细胞中的复制效率及对小鼠致病性的差异,来评价表达不同长度的PA-X基因对H3N2 CIV的影响。结果显示,CIV＿PA-X＿252和CIV＿PA-X＿Knock的聚合酶活性显著(P<0.05)高于CIV＿PA-X＿232,且CIV＿PA-X＿...     

Na_2CO_3胁迫对番茄幼苗生理生化特性的影响

为进一步探究番茄的耐盐机理,采用盆栽试验法,研究了不同浓度Na2CO3胁迫对番茄幼苗脯氨酸含量、SOD、POD及CAT活性的影响。结果表明:随着盐胁迫时间及盐浓度的增加,脯氨酸含量呈现快速上升的趋势;SOD、POD和CAT活性均呈先上升高后下降的趋势。盐胁迫15d,Na2CO3浓度为20mmol·L-1时,SOD、POD活性达到最高值;Na2CO3浓度为5mmol·L-1时,CAT活性达到最高值,之后均呈现下降的趋势。综上,盐胁迫条件下,番茄可调动自身抗氧化酶来提高抗盐性,但随着盐胁迫时间及浓度的增加,番茄抗氧化系统遭到破坏。     

水杨酸分光光度法测定水中的NO_3~-

以水杨酸为显色剂,建立分光光度法测定水中NO3-含量的方法。结果表明,NO3-含量的最佳测定条件为：吸收波长410nm,1.0ml浓硫酸,1.0ml20% NaOH溶液,显色时间20min。此条件下,NO3-含量在0.5～8.0mg/L范围内遵循比尔定律。NO3-的最低检出限为0.1mg/L,加标回收率为98.0%～102.0%。