影响麦胚无细胞合成体系的氨基酸参入及其翻译产物分子量的因子

不同来源的麦种所制成的麦胚无细胞蛋白质合成体系,在以TMV-RNA为模板时,不仅影响氨基酸参人效率,而且影响其合成大分子的能力。参人效率和合成大分子能力并不平行,冬小麦鉴31制成的体系能合成分子量较大的蛋白质。     

Photosynthetic/Photorespiratory Carbon Metabolism in the C(3)-C(4) Intermediate Species, Moricandia arvensis and Panicum milioides

The distribution of ¹⁴C in photosynthetic metabolites of two naturally occurring higher plants with reduced photorespiration, Moricandia arvensis and Panicum milioides, in pulse and pulse-chase ¹⁴CO₂ incorporation experiments was similar to that for the C₃ species, M. foetida and Glycine max. After 6 seconds of ¹⁴CO₂ incorporation, only about 6% of the total ¹⁴C fixed was in malate and aspartate in both M. arvensis and P. milioides. The apparent turnover of the C₄ acids was very slow, and malate accumulated during the day in M. arvensis. Thus, C₄ acid metabolism by M. arvensis and P. milioides had no significant role in photosynthetic carbon assimilation under the conditions of our experiments (310 microliters CO₂ per liter, 21% O₂, 1100 or 1900 micromoles photon per square meter per second, 27°C).

After a 36-second chase period in air containing 270 microliters CO₂ per liter, about 20% of the total ¹⁴C fixed was in glycine with M. arvensis, as compared to 15% with M. foetida, 14% with P. milioides, and 9% with G. max. After a 36-second chase period in 100 microliters CO₂ per liter, the percentage in glycine was about twice that at 270 microliters CO₂ per liter in the C₃ species and P. milioides, but only 20% more ¹⁴C was in glycine in M. arvensis. These data suggest that either the photorespiratory glycine pool in M. arvensis is larger than in the other species examined or the apparent turnover rate of glycine and the flow of carbon into glycine during photorespiration are less in M. arvensis. An unusual glycine metabolism in M. arvensis may be linked to the mechanism of photorespiratory reduction in this crucifer.

     

免疫球蛋白

免疫球蛋白(immunoglobulins),是对含有抗体的三种球蛋白(γ-,β_(2A)-及β_(2M)-球蛋白)的概括语。自1937年Tiselius 提出在电泳上移动最慢的γ-球蛋白就是抗体蛋白以来,人们一直把γ-球蛋白与抗体等同起来看待。近年来由于超速离心法、层析法、凝胶扩散法、免疫电泳法等新技术的使用,发现与免疫有关的蛋白质的理化学性质及免疫学特性颇不均一(Heterogeneity)。例如,在超速离心上有7S与19S之别,在免疫电泳上亦不仅限于电泳图的末端部位,而是通过β-球蛋白一直扩展到α_2-球蛋白区域(图1)。所以正确地     

毛木耳一新变种

本文报道了发现于河北省石家庄地区的木耳科(Auricualariaceae)、木耳属(Auricu-laria)毛木耳的一个白色变种。其色泽如银耳故命名银白木耳[A．Polytricha(Mont.)Sacc. Var．Argentca D．Z．Zhao et C．J．Waag var．Nov．]是经济价值高、可供进一步开发应用的食用菌新菌种。通过三代五次人工驯化培养,生物性状稳定,颜色纯白,朵大肉厚,外观美丽,并具有抗木霉、耐高温,生物效率高等特点。