The epidermal growth factor （EGF） has been shown to promote the proliferation of various types of cells, to maintain the physiological function of the mucosa of the digestive tract, and to promote the healing of the...The epidermal growth factor （EGF） has been shown to promote the proliferation of various types of cells, to maintain the physiological function of the mucosa of the digestive tract, and to promote the healing of the gastric and duodenal ulcers. It has been expressed in many types of bacteria and yeasts. In this article, a bio-reactor was constructed, namely, the human EGF （hEGF） transgenic mini-tomato. On the basis of hEGF gene sequence, a tomato codon preference hEGF gene was chemically synthesized, and it was constructed into the plant expression vector pCAMBIA2300. The transgenic tomato plants containing gene hEGF were obtained through Agrobacterium-mediated transformation. The expression product was determined by radioimmunoassay （RIA） and showed a yield of 3.48± 1.01 ng/g fresh fruits. The intragastric gavage （ig） administration of the rhEGF-containing juice of the transgenic tomato （equivalent to 24 ng rhEGF per mouse a day） for 15 days could significantly protect mice against the alcohol-induced ulceration. The ulcer index, expressed as a degree of the stomach lesion, decreased from 42.20 ±18.13 to 16.25 ±9.57.展开更多
Polyamines（PAs） and nitric oxide（NO） are vital signals in modulating plant response to abiotic stress. However, to our knowledge, studies on the relationship between NO and PAs in response to cold stress in tomato...Polyamines（PAs） and nitric oxide（NO） are vital signals in modulating plant response to abiotic stress. However, to our knowledge, studies on the relationship between NO and PAs in response to cold stress in tomato are limited. Accordingly, in this study, we investigated the effects of putrescine（Put） and spermidine（Spd） on NO generation and the function of Spd-induced NO in the tolerance of tomato seedling under chilling stress. Spd increased NO release via the nitric oxide synthase（NOS）-like and nitrate reductase（NR） enzymatic pathways in the seedlings, whereas Put had no such effect. Moreover, H2O2 might act as an upstream signal to stimulate NO production. Both exogenous NO donor（sodium nitroprusside（SNP）） and Spd enhanced chilling tolerance in tomato, thereby protecting the photosynthetic system from damage. Compared to chilling treatment alone, Spd enhanced the gene expressions of superoxide dismutase（SOD）, peroxidase（POD）, catalase（CAT）, and ascorbate peroxidase（APX）, and their enzyme activities in tomato leaves. However, a scavenger or inhibitor of NO abolished Spd-induced chilling tolerance and blocked the increased expression and activity due to Spd of these antioxidant enzymes in tomato leaves under chilling stress. The results showed that NO induced by Spd plays a crucial role in tomato＇s response to chilling stress.展开更多
基金This work was supported by the Innovation Group Development Project of the Ministry of Education of China (No. IRT0435).
文摘The epidermal growth factor （EGF） has been shown to promote the proliferation of various types of cells, to maintain the physiological function of the mucosa of the digestive tract, and to promote the healing of the gastric and duodenal ulcers. It has been expressed in many types of bacteria and yeasts. In this article, a bio-reactor was constructed, namely, the human EGF （hEGF） transgenic mini-tomato. On the basis of hEGF gene sequence, a tomato codon preference hEGF gene was chemically synthesized, and it was constructed into the plant expression vector pCAMBIA2300. The transgenic tomato plants containing gene hEGF were obtained through Agrobacterium-mediated transformation. The expression product was determined by radioimmunoassay （RIA） and showed a yield of 3.48± 1.01 ng/g fresh fruits. The intragastric gavage （ig） administration of the rhEGF-containing juice of the transgenic tomato （equivalent to 24 ng rhEGF per mouse a day） for 15 days could significantly protect mice against the alcohol-induced ulceration. The ulcer index, expressed as a degree of the stomach lesion, decreased from 42.20 ±18.13 to 16.25 ±9.57.
基金supported by the China Agriculture Research System(No.CARS-25)the Liaoning Innovative Research Team in University(No.LZ2015025),China
文摘Polyamines（PAs） and nitric oxide（NO） are vital signals in modulating plant response to abiotic stress. However, to our knowledge, studies on the relationship between NO and PAs in response to cold stress in tomato are limited. Accordingly, in this study, we investigated the effects of putrescine（Put） and spermidine（Spd） on NO generation and the function of Spd-induced NO in the tolerance of tomato seedling under chilling stress. Spd increased NO release via the nitric oxide synthase（NOS）-like and nitrate reductase（NR） enzymatic pathways in the seedlings, whereas Put had no such effect. Moreover, H2O2 might act as an upstream signal to stimulate NO production. Both exogenous NO donor（sodium nitroprusside（SNP）） and Spd enhanced chilling tolerance in tomato, thereby protecting the photosynthetic system from damage. Compared to chilling treatment alone, Spd enhanced the gene expressions of superoxide dismutase（SOD）, peroxidase（POD）, catalase（CAT）, and ascorbate peroxidase（APX）, and their enzyme activities in tomato leaves. However, a scavenger or inhibitor of NO abolished Spd-induced chilling tolerance and blocked the increased expression and activity due to Spd of these antioxidant enzymes in tomato leaves under chilling stress. The results showed that NO induced by Spd plays a crucial role in tomato＇s response to chilling stress.
