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11.
中国昆明小鼠亚群蛋白质多态性的研究 总被引:7,自引:0,他引:7
本文报道采用电泳技术对北京、上海、长春3市的4个中国昆明小鼠(简称KM)实验群体中24个蛋白质标志研究的结果,与我国1981年从美国引进的NIH小鼠进行比较,显示出:(1)KM小鼠亚群间等位基因组成无明显差异,它们间遗传距离为0.008—0.027,与群体封闭时间成正相关;(2)4个KM小鼠群体间聚类分析发现S:KM群体为特殊一类,该结果与KM亚群间下颌骨分析结果相符;(3)KM与Swiss来源的NIH小鼠群体间在E(?)-3、Es-10、Got-2、Glo-1、Gpt-1、和Mpi-1座位上的等位基因组成存在显著差异,它们之间的遗传距离平均值为0.131±0.011,证实中国KM小鼠为非Swiss来源的一个亚种。 相似文献
12.
Decai Cui J. R. Myers G. B. Collins P. A. Lazzeri 《Plant Cell, Tissue and Organ Culture》1988,15(1):33-45
The origin and development of zygotic and somatic embryos of Trifolium rubens L. was studied with the aid of paraffin sections and light microscopy. Zygotic embryos were collected, fixed and prepared daily from one to ten days after cross-pollination. Somatic embryos were obtained by plating petiole sections on modified L2 medium with 0.015 mgl-1 picloram and 0.1 mgl-1 6-BAP. Cultured petioles were collected and fixed daily from one to 25 days after plating. Two regions in the vascular bundle sheath of cultured petioles gave rise to callus. The first region was adjacent to the phloem fibers and produced friable callus. The second region gave rise to compact callus that was connected to the fascicular cambium. Somatic embryos originated from single cells in the cortex directly without intervening callus formation and from single cells in the friable callus. In addition, embryos arose from meristematic regions in compact callus. Many early stages of embryogenesis (one, two and four-celled stages) were observed in the cortex and friable callus. Zygotic embryogenesis in Trifolium differs from other legumes in that the suspensor is short and has a broad attachment. This arrangement was observed in zygotic embryos of T. rubens and in many somatic embryos. However, a continuum of somatic embryogenesis was observed where some young embryos had a Trifolium suspensor-like arrangement while others were attached to a long narrow suspensor-like structure more characteristic of Medicago. 相似文献
13.
Food consumption, faecal production and nitrogen excretion by minnows, Phoxinus phoxinus , weighing 1–5.5 g were studied at five rations ranging from starvation to ad libitum and four temperatures ranging from 5 to 15°C.
The maximum rate of food consumption (Cmax ) was related to body weight ( W ) and temperature ( T ) by the relationship: C max = aWb1 Tb2 . There were significant daily variations in Cmax , which tended to decline over time. Absorption efficiency increased with increasing ration size and decreasing temperature. Body weight had no significant effect on the faecal production. The equation F = a Cb1 eb2 T described the relationship between faecal production ( F ), food consumption ( C ) and temperature. Ammonia-N predominated over urea-N in the excreta of most experimental fish. The proportion of urea-N in the total nitrogen excreted was generally higher at lower rations than at higher rations. Rates of nitrogen excretion increased with increased ration size and were, to a lesser extent, influenced by temperature. Body weight had no significant effect on the nitrogen excretion by feeding minnows. The equation N = a+bl T+b2 C described the effects of food consumption and temperature on nitrogen excretion ( N ) other than urea-N excretion. The relationship between urea-N excretion ( Nu ), food consumption and temperature was described by the equation Nu = aeb1T ((C+1) b 2.
On the average, 11 % of food energy was lost in faecal production and nitrogen excretion by minnows feeding on whiteworms, Enchytraeus spp. 相似文献
The maximum rate of food consumption (C
On the average, 11 % of food energy was lost in faecal production and nitrogen excretion by minnows feeding on whiteworms, Enchytraeus spp. 相似文献
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对来自赤杨属、木麻黄属、异木麻黄属、沙棘属和杨梅属的六株Frankia代表菌株进行了二十四种碳源利用谱的比较研究(包括简单有机酸、单糖、双糖、三糖和糖醇在内)。结果表明,各菌株在碳源利用种类和程度上有明显差异;简单有机酸盐特别是丙酸钠是所有菌株的良好碳源;菌株Cc01、A11I1和Hr16还能很好地利用丙酮酸钠;除了菌株Hr16能很好地利用纤维二糖,菌株A11I1利用葡萄糖外;糖醇类很少被利用。如果以丙酮酸钠、丙酸钠和乙酸为“诊断性”碳源,则可以将供试菌株分为三个类群,即赤杨——杨梅类群、沙棘类群和木麻黄类群;这与交叉接种和血清学方法得出的结论相吻合。 相似文献
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17.
Single-stranded oligonucleotide primers can be efficiently removed after PCR using E.coli exonuclease VII. Even only a few molecules of double stranded PCR product are unaffected by a treatment which eliminates 20 picomoles of primer in the presence of 500 ng of denatured genomic DNA. Exonuclease VII treatment is rapid and could simplify complicated multistep PCR protocols. 相似文献
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19.
本研究工作中,建立了一个有效的甜菜坏死黄脉病毒的分离提纯程序,解决了该病毒粒体易于聚集难以提纯的问题,其操作要点是,(1)通过Sepharose 2B柱层析代替超离心,有效地除去一些小分子量核酸杂质;(2)经PEG再次沉淀浓缩后,调整pH至酸牲(pH3.0),使病毒充分悬浮以减少凝聚;(3)在病毒等电点(pH4.8~4.9)条件下,进一步沉淀以纯化病毒。根据病毒提取物的OD260/OD280比值,算出核酸含量约4.5%。核酸电泳出现4条带,分子量分别为:2.25×10~(?),1.8×10~(?),1.05×10~(?),0.75×10~(?)道尔顿。病毒提取物经超速离心出现4个界面,沉淀系数分别为,200.8S,165S,125.8S,100S。说明甜菜坏死黄脉病毒可能是4组分病毒粒体。病毒粒体含一蛋白亚基,分子量约为2.05±0.05×10~4道尔顿,由16种共199个氨基酸组成。 相似文献
20.
This paper deals with the role of light in the germination of akinetes of Anabaena azollae. The two maxima action spectra are situated at 385 and 615 nm and the stimulation of the germination process by photosynthate was confirmed. The photoreceptor absorbing at 385 nm was identified as a flavin and that at 615 nm as a phytochrome. A model is suggested for the mode of action of light in the germination of akinetes of blue-green algae.C. Tsui 相似文献