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51.
Between 2006 and 2009, seven strains of infectious bronchitis (IB) virus (IBV) were isolated from vaccinated chicken flocks on different chicken farms in China. The pathogenic characters of seven IBV strains were assessed. Each of the seven strains was infective to the test chickens and could induce an immune response. The results from chicken embryo cross-neutralization assays showed that these strains were antigenically distinct from classic IBV strains of H120, M41, Conn, and Gray. Compared to H120 vaccine strain, point mutation, short insertion, and deletion occurred at many positions in the S1 protein of the seven strains. Five of the seven strains had the motif (HRRRR), which was identical to that of the epidemic IBV strains in China. Two new motifs (HRLRR and RRIRR) emerged in the isolated strains. The homology of the nucleotide and amino acid sequences of the S1 gene among the seven isolates was 81.7%-99.7% and 79.0%-99.4%, respectively. These seven strains were also genetically different from the vaccine strains and non-China IBV strains but closely related to large numbers of Chinese strains. The seven isolates and 36 reference IBV strains were clustered into six distinct groups (I-VI). The seven strains were categorized into groups I, II, and III, forming a big phylogenetic branch, which is closely related to Chinese IBVs, whereas the vaccine strains belonging to group VI are genetically distant from groups I, II, and III. The results from this study indicate that different IBV strains cocirculate in the chicken population in China. 相似文献
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根际加温对无土栽培非洲菊冬季产花的影响 总被引:4,自引:0,他引:4
试验结果表明, 非洲菊7 个切花品种冬季无土栽培根际加温可促进其产花。根温为20 ℃时显著提高了切花的产量与质量, 单株产量、花茎长、茎粗、花重较对照分别提高了71. 34 %、19. 14 %、8. 5 %、23. 72 % , 但对花径的增大作用不显著。根温为15 ℃时可显著提高切花产量, 较对照切花增产33. 21 %; 对花茎长、茎粗生长也有促进作用, 但对花径、花重无显著影响。根际加温对不同品种增加产量与提高质量效果不同, 根际加温至20 ℃时, 品种‘日’、‘签证’与‘莫尔’产量较高, 质量优良: 冬季84 d 产量可达9. 90、9. 56 与9. 30 支/株, 花径为10. 21、9. 92 与10. 05 cm , 花茎长为55. 10、53. 61 与54. 82 cm , 茎粗为0. 65、0. 63与0. 61 cm , 花重为21. 52、22. 68 与22. 50 g。 相似文献
58.
Fu-Hui Wu Shu-Chen Shen Lan-Ying Lee Shu-Hong Lee Ming-Tsar Chan Choun-Sea Lin 《Plant methods》2009,5(1):16-10
Background
Protoplasts isolated from leaves are useful materials in plant research. One application, the transient expression of recombinant genes using Arabidopsis mesophyll protoplasts (TEAMP), is currently commonly used for studies of subcellular protein localization, promoter activity, and in vivo protein-protein interactions. This method requires cutting leaves into very thin slivers to collect mesophyll cell protoplasts, a procedure that often causes cell damage, may yield only a few good protoplasts, and is time consuming. In addition, this protoplast isolation method normally requires a large number of leaves derived from plants grown specifically under low-light conditions, which may be a concern when material availability is limited such as with mutant plants, or in large scale experiments. 相似文献59.
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在开花期,用0、50、100和200mg/kg黄腐酸溶液喷洒白菜型油菜(BrassicaCampestris),结果表明,黄腐酸能提高叶绿素含量,降低叶片电导率,提高叶片相对含水量,降低其水分饱和亏缺,从而增强了油菜抗旱能力.喷洒黄腐酸还显著提高油菜的干物质积累量和籽粒产量。 相似文献