Provitamin A carotenoids in staple crops are not very stable during storage and their loss compromises nutritional quality. To elucidate the fundamental mechanisms underlying carotenoid accumulation and stability, we ...Provitamin A carotenoids in staple crops are not very stable during storage and their loss compromises nutritional quality. To elucidate the fundamental mechanisms underlying carotenoid accumulation and stability, we investigated transgenic potato tubers that expressed the cauliflower Orange （Or） gene. We found that the Or transgene not only promoted retention of 13-carotene level, but also continuously stimulated its accumulation during 5 months of cold storage. In contrast, no increased levels of carotenoids were observed in the tubers of vector-only controls or a yellow- flesh variety during the same period of storage. The increased carotenoid accumulation was found to be associated with the formation of lipoprotein-carotenoid sequestering structures, as well as with the enhanced abundance of phytoene synthase, a key enzyme in the carotenoid biosynthetic pathway. Furthermore, the provitamin A carotenoids stored were shown to be stable during simulated digestion and accessible for uptake by human intestinal absorptive cells. Proteomic analysis identified three major functional groups of proteins （i.e. heat shock proteins, glutathione-S-transferases, and carbohydrate metabolic proteins） that are potentially important in the Or-regulated carotenoid accumulation. Our results show that regulation of carotenoid sequestration capacity is an important mechanism by which carotenoid stability is regulated. Our findings suggest that induction of a proper sink structure formation in staple crops may provide the crops with a unique ability to promote and/or stabilize provitamin A accumulation during plant growth and post-harvest storage.展开更多
Dog has a very sensitive olfactory sensory system. Observation showed that there were great differences in olfactory ability of different breeds of dogs, and even the same dog presented different olfactory abilities u...Dog has a very sensitive olfactory sensory system. Observation showed that there were great differences in olfactory ability of different breeds of dogs, and even the same dog presented different olfactory abilities under different physiological conditions. Thus, the author discussed several factors influencing olfaction of dog from the aspects of gene, environment, anatomy and physiology.展开更多
从云南某铜矿井下酸性污水中分离到嗜酸菌株ynxd-1,对其形态、生长特性、16 S rRNA基因序列及其对低品位硫化镍铜矿的摇瓶浸出效果进行了研究.结果表明:细菌细胞呈短杆状,革兰氏染色阴性,不产芽孢,最适pH值及生长温度分别为2.0和30℃.菌...从云南某铜矿井下酸性污水中分离到嗜酸菌株ynxd-1,对其形态、生长特性、16 S rRNA基因序列及其对低品位硫化镍铜矿的摇瓶浸出效果进行了研究.结果表明:细菌细胞呈短杆状,革兰氏染色阴性,不产芽孢,最适pH值及生长温度分别为2.0和30℃.菌株ynxd-1在10%(W/V)矿浆浓度及30℃温度的条件下摇瓶培养浸出28 d,低品位硫化镍铜矿镍的浸出率为56.4%.16 S rRNA基因序列分析表明,菌株ynxd-1与嗜酸氧化亚铁硫杆菌的同源性达到99%,可以鉴定为嗜酸氧化亚铁硫杆菌菌株.展开更多
文摘Provitamin A carotenoids in staple crops are not very stable during storage and their loss compromises nutritional quality. To elucidate the fundamental mechanisms underlying carotenoid accumulation and stability, we investigated transgenic potato tubers that expressed the cauliflower Orange （Or） gene. We found that the Or transgene not only promoted retention of 13-carotene level, but also continuously stimulated its accumulation during 5 months of cold storage. In contrast, no increased levels of carotenoids were observed in the tubers of vector-only controls or a yellow- flesh variety during the same period of storage. The increased carotenoid accumulation was found to be associated with the formation of lipoprotein-carotenoid sequestering structures, as well as with the enhanced abundance of phytoene synthase, a key enzyme in the carotenoid biosynthetic pathway. Furthermore, the provitamin A carotenoids stored were shown to be stable during simulated digestion and accessible for uptake by human intestinal absorptive cells. Proteomic analysis identified three major functional groups of proteins （i.e. heat shock proteins, glutathione-S-transferases, and carbohydrate metabolic proteins） that are potentially important in the Or-regulated carotenoid accumulation. Our results show that regulation of carotenoid sequestration capacity is an important mechanism by which carotenoid stability is regulated. Our findings suggest that induction of a proper sink structure formation in staple crops may provide the crops with a unique ability to promote and/or stabilize provitamin A accumulation during plant growth and post-harvest storage.
基金Supported by Application Innovation Project of the Ministry of Public Security of the People's Republic of China"Development of Fast Regulation Spray for Smell Performance of Working Dogs"(2014YYCXNCJQ073)
文摘Dog has a very sensitive olfactory sensory system. Observation showed that there were great differences in olfactory ability of different breeds of dogs, and even the same dog presented different olfactory abilities under different physiological conditions. Thus, the author discussed several factors influencing olfaction of dog from the aspects of gene, environment, anatomy and physiology.
文摘从云南某铜矿井下酸性污水中分离到嗜酸菌株ynxd-1,对其形态、生长特性、16 S rRNA基因序列及其对低品位硫化镍铜矿的摇瓶浸出效果进行了研究.结果表明:细菌细胞呈短杆状,革兰氏染色阴性,不产芽孢,最适pH值及生长温度分别为2.0和30℃.菌株ynxd-1在10%(W/V)矿浆浓度及30℃温度的条件下摇瓶培养浸出28 d,低品位硫化镍铜矿镍的浸出率为56.4%.16 S rRNA基因序列分析表明,菌株ynxd-1与嗜酸氧化亚铁硫杆菌的同源性达到99%,可以鉴定为嗜酸氧化亚铁硫杆菌菌株.
