Morphological and molecular analysis of androgenetic, selfed and backcrossed plants produced from a Hordeum vulgare x H, bulbosum hybrid

Anther culture (AC) was carried out on a fertile triploid hybrid between Hordeum vulgare L. (cultivated barley) and H. bulbosum L, (bulbous barley grass) to determine whether AC-derived regenerants differed from progeny obtained through selfing and backcrossing. Chromosome counts were carried out on all plants and DNA was extracted from them to prepare Southern blots for molecular analysis. To identify true recombinants, the blots were probed with rye repetitive sequence probes (pSc119.1 and pScl19.2). which hybridize strongly and specifically to H. bulbosum DNA. Twenty probes that detect single- or low-copy sequences were hybridized with Southern blots containing restricted DNA extracted from 25 AC-derived plants, 11 selfed and six backcrossed progeny that showed hybridizations with pScll9. Although restriction fragment length polymorphisms (RFLPs) were only observed using probes that map to four of the possible 14 chromosome arms, an introgression associated with chromosome 6HS was frequently observed among plants derived from AC. selfing and backcrossing. Plants from AC differed from selfed and backcrossed progeny in their chromosome number; unique RFLP bands that were occasionally observed may indicate chromosomal rearrangements.     

Characterization for agronomic use of cytoplasmic male-sterility in sunflower (Helianthus annuus L.) introduced from H. resinosus Small

A backcrossing programme was carried out both to assess the stability of a cytoplasmic male‐sterility (CMS) source from Helianthus resinosus, designated RES1, and to incorporate it into inbred sunflower lines (HA89, RHA271, RHA801). All the progenies, grown in different environments, were completely male‐sterile. This suggests that the expression of this cytoplasm is stable. Female‐fertility of lines HA89, RHA271 and RHA801 carrying CMS RES1 were compared with those of the corresponding fertile inbred lines. There were no differences in the number of seeds per head. This indicates that female‐fertility is not affected by RES1 cytoplasm. Cytological studies showed that meiosis proceeds normally until the tetrad stage; consequently, the absence of pollen is caused by alterations that take place during postmeiotic stages. With the aim of identifying male‐fertility restorer genotypes, crosses were made between HA89 (CMS RES1) plants and different annual diploid and perennial hexaploid Helianthus species. All the diploid germplasm evaluated behaved as a CMS RES1 maintainer. However, the hexaploid species, H. resinosus, H. x laetiflorus, H. pauciflorus and H. tuberosus, restored pollen fertility in CMS RES1 plants.     

Reduced chromosome association between the short arms of 5H homologues in Hordeum vulgare L. at metaphase I

Rod or ring bivalents at metaphase I (MI) reflect whether crossing-over has occurred on one or both pairs of chromosome arms, respectively, during meiotic prophase (pachytene). In cultivated barley ( Hordeum vulgare ) the highest frequencies of rod bivalents were found for satellite chromosomes (either 5H or 6H). To distinguish between chromosome 5H and 6H associations, a recombinant line derived from an H. vulgare × H. bulbosum hybrid with a hemizygous introgression from H. bulbosum on the short arm of chromosome 6H was probed with 45S rDNA and pSc119.2 using fluorescent in situ hybridization and compared with non-recombinant H. vulgare. The frequencies of rod bivalents, caused by failure of the short arms of 5H chromosomes (5HS) to associate during meiosis in the recombinant line, were similar to the frequencies of rod bivalents involving the satellite chromosomes in H. vulgare. Hence, rod bivalent formation in H. vulgare satellite chromosomes is probably based on reduced association of 5HS, corresponding to a low frequency of genetic recombination. 5HS is, therefore, more likely to show linkage disequilibrium than the other chromosome arms.     

硫酸酯化酵母β-葡聚糖对H1N1猪流感病毒血凝作用和mRNA转录的影响

为研究硫酸酯化酵母β-葡聚糖对流感病毒血凝抑制作用及对mRNA转录的影响,以猪流感病毒A/tianjin/1/TJ2(H1N1)感染MDCK细胞为模型,采用血凝抑制试验(HI)及SYBR Green Real-time PCR方法,探索硫酸酯化酵母β-葡聚糖对流感病毒血凝抑制作用及其对mRNA转录影响。结果显示,硫酸酯化酵母β-葡聚糖在浓度超过1.25 mg/m L时,能对猪流感病毒血凝产生抑制作用,且在5 mg/m L时对猪流感病毒mRNA转录具有抑制作用。因此,硫酸酯化酵母β-葡聚糖具有抑制流感病毒在MDCK细胞复制的作用,其作用机制可能与抑制流感病毒HA靶点及影响mRNA转录有关。     

鸡传染性支气管炎弱毒苗与灭活苗的免疫效果评价

采用鸡传染性支气管炎弱毒疫苗及肾型和呼吸型毒株的灭活苗对鸡进行了免疫，根据鸡免疫后的抗体水平动态变化和攻毒后鸡肾脏和气管水平上的保护力，比较了传染性支气管炎弱毒苗H120与两个不同致病型毒株灭活苗的免疫效果。试验结果表明，弱毒苗虽可诱导较高水平的抗体，但免疫效果较灭活苗差。     

不同基因型苹果的离体再生特性及其对NaN_3的反应

不同基因型苹果叶片培养物再生特性不同，主要表现在再生频率的高低和再生类型的类异，通过培养基中的激素和培养过程的光照调节，可以有效地提高各基因型品种的再生频率。不同基因型苹果叶片培养物对ＮａＮ３诱变处理的反应不同，总体而言，其存活率和再生频率均随ＮａＮ３浓度的提高而下降。不同基因型苹果的适宜ＮａＮ３浓度应有所不同，以３０％存活率为标准，对Ｍ２６、嗄拉，首红，长富２及岩富进行诱变处理的适宜浓度分别为３     

DNA甲基化与细胞分化

DNA甲基化与DNA遗传信息的传递及组织特异性基因的正确表达存在着十分密切的关系。DNA甲基化受组蛋白H 3和DNA甲基化转移酶的调控;甲基化的DNA与许多的蛋白质共同相互作用,调控基因转录,从而导致基因印迹和基因沉默,使细胞向特定方向分化。本文重点综述了DNA甲基化位点、甲基化转移酶及DNA甲基化相关的蛋白质;DNA甲基化与基因印记、基因沉默的关系及其对细胞分化的影响。     

H5N1亚型禽流感病毒血凝素在昆虫杆状病毒系统中表达与活性鉴定

摘要：本实验从质粒pGEM-HA中扩增H5N1亚型禽流感病毒HA基因，构建转移载体pFastBacHT-HA并与E.coliDH10Bac中的Bacmid质粒重组，构建重组转座质粒rBacmid-HA。在脂质体介导下将rBacmid-HA转染sf9昆虫细胞获得重组杆状病毒。在sf9昆虫细胞中表达HA蛋白，通过SDS-PAGE、Western blot和血细胞吸附实验鉴定重组蛋白。结果显示重组HA蛋白分子量约为66kDa，该蛋白与AIV H5亚型鸡血清发生特异性反应，与H7、H9亚型鸡血清不反应，转染重组杆状病毒后的细胞能吸附鸡的红血球，证明HA基因在sf9昆虫细胞中获得了正确表达，不仅具有型特异性，而且有良好的生物反应性。     

孵化液的盐类组成及盐度对巴里坤湖卤虫卵孵化率的影响

本文研究了孵化液的盐类组成及盐度对巴里坤湖卤虫卵孵化率的影响。结果表明．孵化的最适盐度为１０～５０‰；多种盐类的孵化液比单一盐类（Ｎａｃｌ，Ｎａ２ＳＯ４Ｎａ２ＣＯ３）的孵化液更适合于虫卵孵化；含Ｎａ２ＣＯ３的孵化液可得到较理想的孵化效果。     

不同性诱剂对甜菜夜蛾雄蛾诱捕效果的研究

通过大田试验,对3种甜菜夜蛾性诱剂的诱捕效率、持效期等性能进行了测定,并分析比较了它们在不同时间段的性能差异。结果表明,三者之间存在着明显差异,在1~31 d内,诱芯A与诱芯B的平均诱捕量相近,极显著高于诱芯C的平均诱捕量,三者的持效期差异亦然;而诱芯B与诱芯C的最高诱捕量相仿,均明显低于诱芯A。但在1~10 d内,诱芯A和诱芯C的平均诱捕量相近,均极显著高于诱芯B。