自然干燥对冬虫夏草寄主蝠蛾卵孵化的影响

研究在室内自然空气湿度下放置的时间长短对冬虫夏草(Cordyceps)寄主昆虫贡嘎蝠蛾Hepialus gonggaensis Fu et Huang卵孵化率的影响。卵早期的研究结果为:第1批、第2批和第3批卵于室内自然空气湿度下保存的时间达26,11和16h后再保湿都可以正常孵化并且孵化率与对照无显著性差异,所孵化幼虫在饲养初期的成活率分别达62.0%,41.4%和43.4%,与对照无显著性差异。卵中期干燥放置36h的孵化率为66.7%,所孵化幼虫在饲养初期的成活率为50.0%,孵化率和成活率都与对照无显著性差异。卵晚期干燥放置24h的孵化率为70.0%,所孵化幼虫在饲养初期的成活率为49.0%,孵化率和成活率都与对照无显著性差异。以上结果表明,经历一定时间的干燥不会对卵的正常孵化有影响。     

表达EB病毒主要膜蛋白gp350／220的非复制型重组痘苗病毒的构建

利用非复制痘苗病毒质粒载体pNEOCK11β75及pNEOCK,改造了表达EB病毒主要膜蛋白gp350/22的复制型重组痘苗病毒VMA,构建了非复制型重组痘苗病毒VMA△CK。该病毒能在鸡胚原代成纤维细胞（CEF）中正常繁殖,而在人源细胞中不能正常繁殖。在CEF中连续传代至第25代,经PCR证明,该病毒符合非复制型重组痘苗病毒的特征。经免疫荧光及免疫酶斑法证实,VMA△CK可稳定表达gp350/220,且表达水平与VAM无明显差异。VMA△CK经腹腔免疫Balb/C小鼠,4周后能诱生一定水平的抗gp350/220特异性抗体,加强免疫2周后该抗体水平明显升高。这一结果类似于VMA免疫Balb/C小鼠的结果,初免后,VMA△CK且抗痘苗抗体水平明显低于VMA免疫组;加强免疫2周后,两组小鼠的抗痘苗抗体水平趋于一致。上述结果证明,所构建的非复制痘苗病毒不影响目的抗原的表达,也不影响该抗原的免疫原性,但导致病毒毒力下降,而且用该病毒免疫小鼠后小鼠抗痘苗病毒载体的免疫反应明显下降。     

The use of next generation sequencing technology to study the effect of radiation therapy on mitochondrial DNA mutation

The human mitochondrial genome has an exclusively maternal mode of inheritance. Mitochondrial DNA (mtDNA) is particularly vulnerable to environmental insults due in part to an underdeveloped DNA repair system, limited to base excision and homologous recombination repair. Radiation exposure to the ovaries may cause mtDNA mutations in oocytes, which may in turn be transmitted to offspring. We hypothesized that the children of female cancer survivors who received radiation therapy may have an increased rate of mtDNA heteroplasmy mutations, which conceivably could increase their risk of developing cancer and other diseases. We evaluated 44 DNA blood samples from 17 Danish and 1 Finnish families (18 mothers and 26 children). All mothers had been treated for cancer as children and radiation doses to their ovaries were determined based on medical records and computational models. DNA samples were sequenced for the entire mitochondrial genome using the Illumina GAII system. Mother's age at sample collection was positively correlated with mtDNA heteroplasmy mutations. There was evidence of heteroplasmy inheritance in that 9 of the 18 families had at least one child who inherited at least one heteroplasmy site from his or her mother. No significant difference in single nucleotide polymorphisms between mother and offspring, however, was observed. Radiation therapy dose to ovaries also was not significantly associated with the heteroplasmy mutation rate among mothers and children. No evidence was found that radiotherapy for pediatric cancer is associated with the mitochondrial genome mutation rate in female cancer survivors and their children.     

An arabinogalactan isolated from the stems of Cistanche deserticola induces the proliferation of cultured lymphocytes

A purified polysaccharide ACDP-2 was isolated from water extract of the stems of Cistanche deserticola. Chemical and spectroscopic analyses indicated that ACDP-2 is a highly branched arabinogalactan polymer that composes of linked d-galactopyranose and d-glucopyranose, which contains predominantly a branching point at the 6-carbon. The branched side-chains compose of terminal-, 1,5-, and 1,3,5-linked arabinofuranosyl residues. ACDP-2 showed an effect in stimulating the immune response, which when applied onto the cultured mouse lymphocytes induced the cell proliferation in a dose-dependent manner.     

假单胞菌M18调控基因ppbR的克隆及功能研究

假单胞菌(Pseudomonas sp.)M18是促进植物生长的根际细菌,能产生吩嗪-1-羧酸(PCA)和藤黄绿菌素(Plt)两种不同的抗生素.根据生物信息学分析,铜绿假单胞菌PA2572基因编码蛋白可能是一个双元调控系统的应答调节子.本研究从假单胞菌M18基因组中扩增出PA2572同源基因片段ppbR,利用体外定点插入突变和同源重组技术构建了M18的ppbR突变株M18P.研究结果表明,突变株M18P在泳动能力和群集运动能力上有显著的下降.突变株合成PCA的能力比野生型有显著的下降,在发酵液中PCA积累量仅为野生型的50%.在KMB培养基中,突变株Plt的积累量和野生型没有显著的差异.     

小钻‘白城杨2号’小孢子发生及花粉大小变异

利用醋酸洋红染色压片技术,以温室水培小钻‘白城杨2号’(Populus×xiaozhuanica W.Y.Hsu et Liangcv.‘Baicheng-2’)为材料,对其小孢子发生过程中染色体行为及花粉大小变异进行研究。结果表明:(1)‘白城杨2号’小孢子母细胞减数分裂过程中染色体行为存在一定比例的异常现象,包括终变期单价体、中期Ⅰ染色体提前分离、后期Ⅰ和Ⅱ落后染色体和染色体桥、末期Ⅰ和Ⅱ微核、中期Ⅱ纺锤体定位异常以及胞质分裂异常等,这些异常现象的发生与‘白城杨2号’杂种起源有密切关系。(2)‘白城杨2号’小孢子母细胞减数分裂过程中核仁数目存在动态变化,末期Ⅰ和Ⅱ的子核中最多可看到8个小核仁,可能与杨属树种的多倍体起源有关,其染色体组中可能包含8对具核仁组织者区的染色体。(3)‘白城杨2号’产生空瘪花粉率为3.67%,饱满花粉直径在21.3～52.2μm之间,频率分布总体呈近似高斯分布,0.69%的花粉直径超过37μm,表明其可能产生少量未减数的2n花粉。     

Tomato stigma exsertion induced by high temperature is associated with the jasmonate signalling pathway

High temperature (HT) is becoming an increasingly serious factor in limiting crop production with global climate change. During hot seasons, owing to prevailing HT, cultivated tomatoes are prone to exhibiting stigma exsertion, which hampers pollination and causes fruit set failure. However, the underlying regulatory mechanisms of the HT‐induced stigma exsertion remain largely unknown. Here, we demonstrate that stigma exsertion induced by HT in cultivated tomato is caused by more seriously shortened stamens than pistils, which is different from the stigma exsertion observed in wild tomato species. Under the HT condition, the different responses of pectin, sugar, expansin, and cyclin cause cell wall remodelling and differentially localized cell division and selective cell enlargement, which further determine the lengths of stamens and pistils. In addition, auxin and jasmonate (JA) are implicated in regulating cell division and cell expansion in stamens and pistils, and exogenous JA instead of auxin treatment can effectively rescue tomato stigma exsertion through regulating the JA/COI1 signalling pathway. Our findings provide a better understanding of stigma exsertions under the HT condition in tomato and uncover a new function of JA in improving plant abiotic stress tolerance.