排序方式: 共有11条查询结果,搜索用时 78 毫秒
1.
The role of the cilia in the locomotion (“gliding”) of Tetrahymena thermophila in a semi-solid medium has been studied when cells were migrating in gradients of attractant. Video recordings and computer-aided motion analysis of migrating cells and their ciliary activity show that Tetrahymena thermophila migrate by swimming forward in semi-solid methyl cellulose, using their cilia. Ciliary reversals occur at certain intervals and cause a termination (“stop”) of cellular migration. Cells with reversed cilia resume forward migration when normal ciliary beating resumes. In gradients of attractants, cells migrating towards the attractant suppress ciliary reversals, which leads to longer runs between stops than in control cells. Cells migrating away from the attractant have a higher frequency of ciliary reversals than the control cells resulting in shorter runs. Stimulated cells adapt to a particular ambient concentration of attractant several times during migration in the gradient. Adaptation is followed by de-adaptation, which occurs during the “stop”. In the presence of cycloheximide, a strong inhibitor of chemoattraction, the attractant-induced suppression of ciliary reversal is abolished (cells become desensitized to the attractant). It is concluded that Tetrahymena has a short-term memory during adaptation. This is important for the efficiency of migration towards an attractant. 相似文献
2.
高山红景天(Rhodiola sachalinensis)遗传变异及其濒危机制的探讨 总被引:11,自引:3,他引:8
采用淀粉凝胶电泳手段,等位酶分析技术对分布于黑龙江大海林林业局高山红景天天然分布区内3个亚种群及吉林长白山1个亚种群的9种酶系统18个位点进行了遗传分析,结果表明种群内存在一定的遗传变异(从态位点百分比为30.55%,等位基因平均数为1.333)但不是很丰富,主要是该种类狭窄的分布区致使生境单一及人为破坏其本身的生物学特性长期的进化过程中相互适应相互选择的结果。在黑龙江的分布区内各亚种群之间一致度 相似文献
3.
Ze LIU Wei-dong LI Ming-bo SUN Lei MA Zi-quan GUO Shu-de JIANG Guo-yang LIAO Jing-si YANG Chang-gui LI 《Virologica Sinica》2010,(1)
Due to the insufficient supply of embryonated chicken eggs,the preparation of large quantities of inactivated influenza vaccines will require an alternative virus culture system after the emergence or reemergence of a pandemic influenza virus.The Vero cell is one of the ideal options since it was used for producing many kinds of human vaccines.However,most of the influenza viruses can not grow well in Vero cells.To develop a new influenza vaccine with Vero cells as a substrate,the virus needs to adapt to th... 相似文献
4.
5.
Rehfeldt G. E. 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1977,50(1):3-15
Summary Potentials for improvement of the interior variety of Douglas-fir (Pseudotsuga menziesii var. glauca) by hybridization with the coastal variety (P.m. var. menziesii) were explored. The primary objective was to assess possibilities for increasing growth potentials of the interior variety while maintaining adaptation to relatively cold inland environments. Seventy full-sib hybrid families and their half-sib parental lines were grown in two contrasting environments common to the interior variety. Nine traits related to growth, phenology, and freezing tolerance in 4-year-old trees were compared.For traits related to growth (height and diameter) in the inland environment, hybrids equaled the growth of the coastal variety and exceeded the interior variety by 40 percent. For traits related to adaptation (bud burst, bud set, frost damage, tree form, and freezing tolerance), hybrids were intermediate but approached levels characteristic of the interior variety. Survival of hybrids equaled that of the interior variety and was superior to that of the coastal variety.Hybrid characters could not be predicted reliably from those of parental lines. Yet, quantitative genetic analyses suggest that expression of characters related to growth depends on nonadditive genetic effects, but expression of those related to adaptation is somewhat dependent on additive effects.Realization of the tremendous potential of hybridization for improvement of the interior variety will require at least one backcross generation or additional crosses utilizing introgressed populations. 相似文献
6.
Ze Liu Wei-dong Li Ming-bo Sun Lei Ma Zi-quan Guo Shu-de Jiang Guo-yang Liao Jing-si Yang Chang-gui Li 《中国病毒学》2010,25(1):65-70
Due to the insufficient supply of embryonated chicken eggs, the preparation of large quantities of inactivated influenza vaccines
will require an alternative virus culture system after the emergence or reemergence of a pandemic influenza virus. The Vero
cell is one of the ideal options since it was used for producing many kinds of human vaccines. However, most of the influenza
viruses can not grow well in Vero cells. To develop a new influenza vaccine with Vero cells as a substrate, the virus needs
to adapt to this cell substrate to maintain high growth characteristics. By serial passages in Vero cells, the B/Yunnan/2/2005va
(B) strain was successfully adapted to Vero cells, with the hemagglutination titer (HAT) of the virus reaching 1:512. The
high growth characteristic of this strain is stable up to 21 passages. The strain was identified by hemagglutination inhibition
(HAI) test and sequencing respectively; the HA1 gene sequence of the virus was cloned and analyzed. The screening and establishment of high growth B virus provides an important
tool for influenza vaccine production in Vero cells. 相似文献
7.
长白红景天天然种群遗传多样性及遗传分化 总被引:10,自引:1,他引:9
本研究利用水平淀粉凝胶电泳技术对分布于黑龙江省大海林业业局平顶山及吉林省的长白山北坡的四个海拔梯度的长白红景天的遗传多样性及遗传分化进行了初步分析, 相似文献
8.
目的建立狂犬病病毒固定毒CTN-1V株在人二倍体细胞Walvax-2株上的传代适应株。方法用狂犬病病毒固定毒CTN-1V株经昆明小鼠鼠脑回传后的病毒接种Walvax-2细胞,连续传代,检测各代次病毒的滴度及免疫原性。结果 CTN-1V株能较好地适应Walvax-2细胞,通过连续带毒传代至第7代,病毒滴度可达6.78 lg LD50/mL,并在第10~15代内滴度维持在7.0 lg LD50/mL以上,15~30代滴度稳定在7.0 lg LD50/mL左右。以15代适应毒株CTN-1V-HDC P15制备的疫苗原液,各项指标均符合《中华人民共和国药典》三部(2010版)的要求,疫苗效力在6.0IU/剂以上。结论所获人胚肺二倍体细胞Walvax-2株传代适应狂犬病毒固定毒株CTN-1V-HDC可用于人用狂犬病疫苗的生产开发。 相似文献
9.
该研究以斑马鱼为(Danio rerio)对象,研究了四周无氧运动训练对斑马鱼行为、形态、生长、肌肉生化组分及代谢酶活性的影响。旨在探索斑马鱼对无氧运动训练的适应性变化,为进一步了解鱼类适应无氧运动训练的分子机制提供基础数据。结果发现:斑马鱼的日常活跃程度经四周无氧运动训练后显著降低,群聚程度增加;训练组个体体重和体长增长减缓,更利于运动;肌糖原含量显著增加,运动持久能力加强;肌肉乳酸脱氢酶(LDH)活性显著增高,柠檬酸合成酶(CS)活性显著降低,无氧代谢能力加强。即,斑马鱼无氧运动能力和无氧代谢能力在训练后得以明显提升。 相似文献
10.