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Spiroplasma has been successfully isolated from the honey bee (Apis mellifera) and cultivated in R-2 medium in China. The isolate, CH-1 is obtained through triple cloning. CH-1 shows a helical morphology and a contractile movement. It is 0.17 μm in diameter and its length varies considerably with different growth periods. CH-1 forms granular-type and/or fried-egg-shaped colonies, 75—210 μm in diameter, on R-2 medium. It grows normally at temperatures ranging 25—35℃ (the optimum being 28—32℃). The optimal pH for growth is 7.0. The best growth occurs in medium containing 0.25 mol/L of sucrose. Under the optimal condition, its growth reaches the stationary phase 48 h after subculture. CH-1 cannot grow in serum-free medium and its growth is inhibited by digitonin. CH-1 can metabolize glucose, fructose, maltose, and trehalose. It can dehydrate arginine, CH-1 does not have an ability to utilize urea, nor dehydrate gelatin, nor reduce methylence blue. The taxonomic position of CH-1 has also been discuss 相似文献
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Plasma membranes prepared from pig liver incubated with insulin (50—300 μU/ml) resulted in the release of at least two insulin chemical mediators. They appeared to modulate the activity of adenylate cyclase in liver plasma membrances of pig. One of them was fraction 1 of insulin mediator (M. W. about 3700—4000 dalton) which markedly stimulated the activity of the enzyme, the other was fraction 2 of insulin mediator (M. W. about 1000 dalton) which inhibited the enzyme activity. The results showed that the inhibitor of fraction 2 generated was significantly higher than that of fraction 1 when the membranes were incubated with insulin of low concentration (50—100 μU/ml). On the other hand, the generation of stimulator of fraction 1 from plasma membranes incubated with insulin of high concentration (200 μU/ml) was higher than that of fraction 2. So the ratio of yield between two mediators produced from the membranes was dependent on the concentration of insulin added. The results also showed that the 相似文献
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本文讨论了高斯光束照明下的Talbot近似自成像的性质.提出了利用Talbot自成像测量高斯光束发散角的简便方法;也提出在满足一定条件下,可得到自成像的超高倍放大率. 相似文献
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介绍了一种水冷、陶瓷封接结构的空心阴极放电装置.研究了He、H_2、N_2在120nm~20Onm范围内该装置的真空紫外辐射特性,获得了100~600mA电流范围内的辐射强度与放电电流的关系,以及充气气压变化对它的影响.实验表明:在实验条件下,主要发射谱线为氮的原子线和氦的离子线;辐射谱线强度在0.03~0.72mW·cm~(-2);气压改变时,N_2、H_2辐射强度有一极大值,而He的离子线辐射强度则出现二个极大;在He/H_2混合气体放电时,随着He的加入,氢分子带光谱有明显下降. 相似文献