鸡痘病毒282E_4株基因组2.9kbBamHI片段的序列测定与分析

对我国鸡痘病毒 ( FPV) 2 82 E4株基因组 2 .9kb Bam HI片段进行了序列测定与分析。结果表明 ,该片段全长 2 92 3 bp,A T含量为 72 .0 8%,含 6个完整的开放读码框架 ( ORF)和 2个不完整的 ORF,最大的ORF所编码多肽的相对分子质量为 2 4 60 0。在 2个 ORF的上游存在痘苗病毒晚期启动子的保守序列TAAAT,在 6个 ORF的下游和 2个 ORF的编码区内存在痘苗病毒早期转录终止信号 T5NT。把该片段的核苷酸序列和每个 ORF所编码的氨基酸序列分别对 EMBL核酸序列库和 SWISS-PROT蛋白质序列库进行了同源性搜索 ,未发现同源性片段     

Gender,caponization and exogenous estrogen effects on lipids,bone and blood characteristics in Taiwan country chickens

This study investigated gender, caponization and exogenous estrogen effects on lipids, bone and blood characteristics in Taiwan country chickens. Thirty male chickens were caponized at 8 weeks (capons); 15 capons were injected with estrogen (5 mg/bird estradiol 3‐benzoate) every 2 weeks from 8 to 28 weeks, and 15 sham‐operated male (shams) chickens and 15 females were selected for this trial. The results showed that the shams had lower relative abdominal and chest subcutaneous fat than females (P < 0.05). The estrogen‐treated capons had greater relative abdominal and chest subcutaneous fat than shams and capons (P < 0.05), which might result from higher blood very low‐density lipoproteins and triacylglycerol concentrations (P < 0.05). Caponization could dramatically increase relative abdominal fat (506%; P < 0.05). The shams had higher tibia weight and biomechanical properties, such as maximum bone strength and bending moment values than the capons (P < 0.05). Tibia biomechanical properties were reduced by estrogen treatment (P < 0.05). The females obtained the lowest biomechanical value in all treatments (P < 0.05). Histological examination revealed cavity formation in the cortical bone of estrogen‐treated capons and female chickens, which suggested that estrogen reduced bone biomechanical properties by destroying its structural integrity.     

大豆铁结合蛋白基因在旱稻中的表达及铁含量分析

【目的】尝试利用转基因方法提高旱稻铁含量。【方法】采用基因枪和农杆菌转化法，将水稻胚乳特异表达的谷蛋白基因启动子GluB-1驱动下的大豆铁结合蛋白基因转入2个优良旱稻品种“旱稻297”和“旱稻277”。利用PCR、Southern杂交分析方法验证转化结果。【结果】转基因植株T1代RT-PCR证明，外源基因在种子中特异表达。T1～T3代的PCR检测证明铁结合蛋白基因已经稳定遗传。多数转基因植株T0～T3代种子中铁含量高于未转化植株，最高达到未转化对照的2倍以上。【结论】利用基因枪和农杆菌转化法可将大豆铁结合蛋白基因导入旱稻基因组中，并使转基因稻米铁含量增高。     

花叶病大蒜的茎端组织脱毒培养

本文论述了用MS(1962)培养基添加吲哚乙酸(IAA)、细胞激动素(KT)、萘乙酸(NAA)、2,4—二氯苯氧乙酸(2,4—D)、6—苄基嘌呤(BA)等生长调节物质,对开平金山火蒜及广州硬尾骨蒜两品种茎端0.100～0.125mm长的分生组织进行培养,获得了无毒种蒜,并提出了适于此两种大蒜无毒苗培养的培养基配方、生长调节质物的组合和浓度、以及光温条件等一套方案;论证了2,4—D、NAA、BA、光照和温度对愈伤组织诱导、芽分化和球茎形成上的作用,并对大蒜不同组织部位的培养作了初步的探讨。     

Transcontinental Tidal Gravity Profile across the United States

Data obtained from a transcontinental tidal gravity profile across the United States were analyzed. Results for the principal tidal constituents M(2) and O(1) have shed light on the long-standing problem of the indirect influence of ocean tides on the solid-earth tide. The profile consists of nine observational stations distributed almost evenly around latitudes 39 to 41 degrees north across the United States. The observed values of the gravimetric factor and the phase were found to depend on the tidal characteristics of the Atlantic and Pacific oceans. There is no observable correlation between tidal gravity parameters and the regional geology. When the influence of ocean tides is taken into account, it is possible for the first time to bring the gravimetric factors and phases for all the stations of a transcontinental network into a consistent system within the framework of the earth tidal theory.     

农民增收与城镇化发展的动态计量分析

在建立VAR模型的基础上,运用脉冲响应函数和预测方差分解来刻画城镇化发展与农民收入增长关系的相关性。结果表明,我国城镇发展与农民收入增长呈较强的正相关。因此,在当前条件下,加速推进城镇化发展是持续增加农民收入的重要途径。     

Control of alternative splicing by the differential binding of U1 small nuclear ribonucleoprotein particle.

Cellular factors controlling alternative splicing of precursor messenger RNA are largely unknown, even though this process plays a central role in specifying the diversity of proteins in the eukaryotic cell. For the identification of such factors, a segment of the rat preprotachykinin gene was used in which differential expression of neuropeptides gamma and K is dependent on alternative splicing of the fourth exon (E4). Sequence variants of the three-exon segment, (E3-E4-E5) were created, resulting in a sensitive assay for factors mediating the splicing switch between E4-skipping and E4-inclusion. A dinucleotide mutation in the 5' splice site of E4 that increase base-pairing of this site to U1 small nuclear RNA resulted in uniform selection of E4, whereas a control mutation that destroyed base-pairing resulted in uniform E4-skipping. Affinity selection of spliceosomes formed on these functionally distinct substrates revealed that the extreme difference in splicing was mediated by differential binding of the U1 small nuclear ribonucleoprotein particle (snRNP) to the 5' splice site of E4. These data show that, apart from its established role in selecting 5' splice sites, U1 snRNP plays a fundamental role in 3' exon selection and provides insight into possible mechanisms of alternative splicing.     

品牌危机管理机制——以乳制品行业为例

品牌形象一直企业最关心的问题,但是品牌危机问题日趋普遍。文章试图以乳制品行业为例,浅析品牌危机的管理机制。