排序方式: 共有27条查询结果,搜索用时 46 毫秒
1.
秋水仙素诱导青虾次级卵母细胞二倍体初探 总被引:3,自引:0,他引:3
以青虾卵巢为材料,采用秋水仙素诱导多倍体次级卵母细胞.经滴片试验,确立此实验最佳滴片高度为1.5cm,通过设置5个秋水仙素浓度(0.08~0.40mg/mL)及3个作用时间(6~24h),观察发生染色体加倍的细胞相对数目.实验结果表明:在使用秋水仙素的浓度为0.08~0.40mg/mL,处理6~24h时都可以获得多倍体卵细胞.在秋水仙素浓度是0.32mg/mL,处理6h可得到最高二倍体突变率(32.58%).还测试了0.32mg/mL COM作用6h时ATPase活性与生理盐水对照组的变化,结果显示COM会在一定程度上影响细胞的新陈代谢.但是50%左右的成活率表明,这种诱导突变的方法仍具有一定的应用价值. 相似文献
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在华外商直接投资对我国产业结构的双重影响与对策研究 总被引:9,自引:0,他引:9
近几年,在华外商直接投资迅速增加,掀起了新一轮在华投资热潮。我国三次产业结构日趋合理,在华外商直接投资在其中起到了积极和消极两方面的作用。本文分析了在华外商直接投资的现状及其对我国产业结构影响的正负效应,并提出了相关对策。 相似文献
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Fan Yu Jun Xiao XiangYang Liang ShaoJun Liu GongJian Zhou KaiKun Luo Yun Liu Wei Hu YaPing Wang ZuoYan Zhu 《科学通报(英文版)》2011,56(16):1679-1684
Triploid carp (100%) with 150 (3n=150) chromosomes were obtained by crossing the females of improved tetraploid hybrids (♀,
4n=200) of red crucian carp (♀)×common carp (♂) with the males of diploid yellow river carp (♂, 2n=100). The crosses yielded
transgenic triploid carp (positive triploid fish, 44.2% of the progeny) and non-transgenic triploid carp (negative triploid
fish). Histological examination of the gonads of 24-month-old positive triploid fish suggested they were sterile and the fish
were not able to produce mature gametes during the breeding season. Morphologically, both the positive and negative triploid
fish were similar. They had a spindle-shaped, laterally compressed, steel grey body with two pairs of barbells. Most of the
quantifiable traits of the triploid carp were intermediate between those of the two parents. The positive and negative triploid
fish were raised in the same pond for 2 years. The mean body weight of the positive triploid fish was 2.3 times higher than
the negative triploid fish. The weight of the largest positive triploid fish was 2.91 times higher than that of the largest
negative triploid fish. Thus, we produced fast-growing transgenic triploid carp that have a reduced ecological risk because
of their inability to mate and produce progeny. 相似文献
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Aging appears to be an irreversible process. Here we report that nicotinamide (NAA) can induce rapid and reversible reversion
of aging phenotypes in human diploid fibroblasts in terms of cell morphology and senescence-associated β-galactosidase activity.
Although NAA seems to enhance the replicative potential of the cells, it has little effect on their growth rate and life span,
suggesting that NAA action is rather separated from the cellular replicative system. The effects are unique to NAA: none of
the NAA-related compounds examined (an NAD precursor/niacin, NAD analogs, and poly(ADP-ribose) polymerase inhibitors) exerted
similar effects. Thus, NAD-related metabolism and poly(ADP-ribosyl)ation are unlikely related to the NAA action. On the other
hand, histone acetyltransferase (HAT) activity was elevated in NAA-exposed cells, while in aged cells, HAT activity and histone
H4 acetylation were lowered. Taken together, the results suggest that NAA may cause rejuvenation by restoring, at least in
part, altered gene expression in aged cells through its activation of HAT.
Received 27 August 2001; received after revision 15 October 2001; accepted 15 October 2001 相似文献
5.
肝片吸虫和巨片吸虫染色体和同工酶的研究 总被引:4,自引:0,他引:4
本文研究了来自国内数省份的片形吸虫的染色体和同工酶,发现肝片吸虫的染色体为三倍体型,巨片吸虫的染色体为二倍体型。根据二者核型相近、酯酶同工酶一致以及生活史各期虫体形态相似,作者认为肝片吸虫是巨片吸虫的同源三倍体的种类。 相似文献
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水稻悬浮细胞系的建立 总被引:8,自引:0,他引:8
对包括广亲和材料、恢复系、花培后代在内的30个水稻不同基因型的品种(系)在MS培养基中的培养能力进行了调查.根据出愈率的高低和愈伤组织培养能力,把它们分成Ⅰ,Ⅱ,Ⅲ3种类型.从Ⅰ类型中挑选CPSLO17和IR21820-154-3-2-2-8用N6液体培养基进行液体培养,CPSLO17建立了悬浮细胞系,证实基因型的差异是决定建立良好悬浮细胞系的关键因素之一.此外还考察了低锌胁迫对水稻悬浮细胞系和幼胚愈伤分化率的影响. 相似文献
9.
针对粒子群算法和差分进化算法的不足,根据生物遗传学规律,提出了双倍体差分进化粒子群算法,并将其用于具有集送货需求车辆路径问题的求解中.个体有显性隐性两种状态,显性状态执行粒子群优化规则,隐性状态执行差分进化规则,通过比较适应度显性隐性可以互换.根据算法和问题特点,提出了一种实数编解码方案,使用启发式算法修正和改进算法结果.通过仿真实验,分析讨论了算法的参数,并与其他算法进行了比较,表明该算法是求解具有集送货需求车辆路径问题的有效方法. 相似文献
10.
人胚肺二倍体细胞株KMB17在培养过程中的自然凋亡 总被引:1,自引:1,他引:0
用延长培养周期方法诱导人二倍体胚肺细胞株KMB17自然凋亡,经光学显微镜、荧光显微镜、细胞流式仪、电子显微镜,证明KMB17细胞出现典型的凋亡特征:细胞圆缩、细胞核浓缩破裂、核染色质凝缩后分布于核膜边缘呈新月状和典型的凋亡峰.研究表明人胚肺二倍体细胞(KMB17)在培养过程中易出现自然凋亡.提示可望通过提高细胞对环境压力的耐受能力,预防或延缓细胞培养过程中的自然凋亡,提高操作单元细胞产品的生产效率. 相似文献