Retinal receptors in rodents maximally sensitive to ultraviolet light

High sensitivity to near-ultraviolet light is a fundamental feature of vision in many invertebrates. Among vertebrates there are some amphibians, birds and fishes that are also sensitive to near-ultraviolet wavelengths. This sensitivity can be achieved through a class of cone photoreceptor containing an ultraviolet-sensitive pigment. Although these receptors were thought not to exist in the eyes of mammals, we now report that some rodents have a retinal mechanism that is maximally sensitive to ultraviolet light.     

The sulfur metabolism regulator MetR is a global regulator controlling phytochrome-dependent light responses in Aspergillus nidulans

Phytochrome-dependent light signaling has been studied in several fungi.In Aspergillus nidulans light-stimulated phytochrome activates the high-osmolarity glyce...     

植物体内核定位信号介导的蛋白质核转运

介绍了植物体内核定位信号的类型和结构特点及由核定位信号介导的蛋白质核转运机理。     

根癌农杆菌介导的绿色荧光蛋白基因在水稻植株中的表达

将改良的绿色荧光蛋白（EGFP）基因插入到植物表达载体中,构建了ubi启动子驱动下的植物表达载体p13UEGFP．通过根癌农杆菌介导转化水稻的胚性愈伤组织,经潮霉素筛选,获得抗性愈伤组织和再生植株．对T2代植株进行PCR分析、激光共聚焦显微镜检测和RT—PCR分析,结果表明,绿色荧光蛋白基因已经在转基因植株中稳定表达．     

Enhancements in biologically effective ultraviolet radiation following volcanic eruptions.

Aerosols injected into the stratosphere by large volcanic eruptions may induce ozone destruction through processes including heterogeneous chemical reactions. The effect of ozone reductions on surface ultraviolet irradiation is not obvious, however, because aerosols also increase the reflection of sunlight. Here we use a radiative transfer model to estimate the changes in biologically effective ultraviolet radiation (UV-BE) at the Earth's surface produced by the El Chichón (1982) and Mount Pinatubo (1991) eruptions. We find that in both cases surface UV-BE intensity can increase because the effect of ozone depletion outweighs the increased scattering.     

Endothelium-dependent relaxation in rat aorta may be mediated through cyclic GMP-dependent protein phosphorylation

The action of some vascular smooth muscle relaxants depends on the presence of the endothelium. We have recently shown that relaxation may be mediated through the formation of cyclic GMP. The nitrovasodilators are another class of relaxants which exert their effects through the formation of cyclic GMP, although their relaxation is independent of the presence of the endothelium. Their relaxant properties seem to depend on free radical formation--specifically, the formation of nitric oxide. The NO-induced smooth muscle relaxation is proposed to occur through activation of guanylate cyclase and the formation of cyclic GMP. Protein phosphorylation is thought to be a common event in the pathway for many biological phenomena. Moreover, sodium nitroprusside and 8-bromo cyclic GMP induce similar patterns of protein phosphorylation in intact rat thoracic aorta. Here we report that the patterns of protein phosphorylation induced by the endothelium-dependent vasodilators and nitrovasodilators were identical. Incorporation of 32P into myosin light chain was decreased by both classes of agents. Removal of the endothelium abolished the changes in phosphorylation with the endothelium-dependent vasodilator (acetylcholine), but not those with the nitrovasodilator (sodium nitroprusside). These results suggest that endothelium-dependent vasodilators and nitrovasodilators induce relaxation through cyclic GMP-dependent protein phosphorylation and dephosphorylation of myosin light chain.