Background: Although it has been recognized that photoageing and chronological ageing differ in various morphological and biological aspects, the characteristic alterations of cutaneous neurogenic factors in photoaged...Background: Although it has been recognized that photoageing and chronological ageing differ in various morphological and biological aspects, the characteristic alterations of cutaneous neurogenic factors in photoaged skin are poorly characterized. Objectives: To characterize cutaneous neurogenic factors, including innervation, neuropeptides, nerve growth factor and interactions of mast cells, in photoaged skin. Subjects and methods: Paired biopsy specimens were obtained from sun-exposed volar forearm skin and from sun-protected dorsal upper arm skin of 20 elderly subjects. Various cutaneous neurogenic factors, including innervation, neuropeptides, neurokinin receptor, nerve growth factor, neurogenic inflammation and morphology of mast cells, were compared in sun-exposed vs. sun-protected skin quantitatively and qualitatively. Results: Cutaneous neurogenic factors associated with photoageing were characterized by a significant increase in the densities of dermal and intraepidermal nerve fibres, a correlation between epidermal innervation and the severity of photodamage, increases in the number of neuropeptidergic sensory nerve fibres in the dermis and in tissue levels of sensory neuropeptides, increases in the content of nerve growth factor, reduced expression of neurokinin receptor 1 by epidermal keratinocytes and by vascular endothelial cells and a tachykinin-specific reduction of cutaneous neurogenic inflammation. Mast cells in photodamaged skin showed several characteristic morphological features, including various degrees of activation and an intimate association with fibroblasts, which were distinct from those in sun-protected skin. Furthermore, mast cells in photodamaged skin possessed larger amounts of substance P within their granules than did those in sun-protected skin. Conclusions: These findings document for the first time characteristic alterations of cutaneous neurogenic factors in photodamaged skin and suggest that the cutaneous nervous system may be involved in photoageing processes.展开更多
[Objective]The aim was to study the effects of sunflower artificial aging on seed vigor and physiological characteristics.[Method] The varieties of seed germination capacity,vigor of germination,germination index,vigo...[Objective]The aim was to study the effects of sunflower artificial aging on seed vigor and physiological characteristics.[Method] The varieties of seed germination capacity,vigor of germination,germination index,vigor index,peroxidase（POD） activity,superoxide dismutase（SOD） activity and malondialdehyde（MDA） content for four sunflower germplasms such as＇SunM20＇,＇Deep Purple Minle＇,＇Da San Kui Hua 4＇and＇Ji Kui 24＇were studied under high temperature and high humidity conditions（100% RH,45 ℃） for different days（0 d,2 d,4 d,6 d,8 d,10 d）.[Result]The result showed that the germination capacity,vigor of germination,germination index,vigor index,POD activity,SOD activity declined gradually with the increase of seed aging days,whereas MDA content enhanced by degrees;The diggerences of resistance to artifical aging existed among the four accessions,＇SunM20＇was the most resistant one,and exhibited the strongest seed vigor,highest activities of two protective enzyme（POD,SOD） and lowest content of MDA at the uniform condition,moreover,the seed vigor and protective enzyme activities of＇SunM20＇changed slowest among the four materials during the aging process.[Conclusion]The distinct reduction of POD,SOD activities maybe the main reasons for the decrease of sunflower seed vigor at the artificial aging,and the gradual accumulation of a few MDA accelerated seeds aging.展开更多
Reasons causing or accelerating seed aging are mainly damage of mem- branes, DNA and proteins, decline of protein synthesis capacity and excessive ac- cumulation of reactive oxygen species. With the application of nat...Reasons causing or accelerating seed aging are mainly damage of mem- branes, DNA and proteins, decline of protein synthesis capacity and excessive ac- cumulation of reactive oxygen species. With the application of natural aging or artifi- cial aging methods, it was reported that quantitative trait loci （QTLs） of seed stora- bility in rice were widely distributed on the chromosomes except the 10th chromo- some. In this paper, we reviewed the progresses in the research on physiological- biochemical and genetic mechanisms of seed aging, and analyzed the existing problems and developing prospect in molecular breeding of rice with improved seed storability, in order to provide reference for the basic research and genetic improve- ment of rice seed storabUity.展开更多
Background: The majority of skin changes associated with ageing are caused by photoageing and reflect cumulative sun exposure. Although the actinic damage plays a major role in skin pigmentation, it is also important ...Background: The majority of skin changes associated with ageing are caused by photoageing and reflect cumulative sun exposure. Although the actinic damage plays a major role in skin pigmentation, it is also important to examine the effects of chronological cellular ageing on the pigmentation. The chief cellular components of the skin other than melanocytes are keratinocytes and fibroblasts, and the influences of age-related changes in those cells on skin pigmentation have not been elucidated. Objective: To clarify the effects of cellular ageing of keratinocytes and fibroblasts on age-related skin pigmentation. Methods: Using ELISA analysis, we measured the level of melanogenic cytokines secreted by cultured keratinocytes and fibroblasts derived from skin of various chronological ages. We also compared the cytokine secretion by cultured keratinocytes between the second and fifth cultures. Results: There was no correlation between age and hepatocyte growth factor (HGF), stem cell factor (SCF), and basic fibroblast growth factor (b-FGF) secretion by fibroblasts. On the other hand, a significant positive correlation existed between age and interleukin ((IL)- 1α secretion (R2 = 0.50, P = 0.002), and a relatively weak correlation existed between age and endothelin- 1(ET- 1) secretion (R2 = 0.17,P = 0.051, not significant). The IL- 1α secretion by keratinocytes was significantly increased in the fifth cultures compared with the second cultures (P < 0.005). Conclusions: These findings suggest that IL- 1α secretion increases as cells grow older, and the increased secretion of IL- 1α by aged keratinocytes may stimulate HGF production in dermal fibroblasts paracrinely and ET- 1 production in keratinocytes autocrinely, which stimulates melanocyte proliferation and induces an increase of tyrosinase activity in melanocytes. Because IL- 1α is a primary mediator that responds to inflammation and injury, the transcription of genes involved in skin inflammation may be persistently induced in the aged skin. Thus the increased secretion of IL- 1α by aged keratinocytes in the aged skin may play a role in the accentuated cutaneous pigmentation and other skin ageing.展开更多
文摘Background: Although it has been recognized that photoageing and chronological ageing differ in various morphological and biological aspects, the characteristic alterations of cutaneous neurogenic factors in photoaged skin are poorly characterized. Objectives: To characterize cutaneous neurogenic factors, including innervation, neuropeptides, nerve growth factor and interactions of mast cells, in photoaged skin. Subjects and methods: Paired biopsy specimens were obtained from sun-exposed volar forearm skin and from sun-protected dorsal upper arm skin of 20 elderly subjects. Various cutaneous neurogenic factors, including innervation, neuropeptides, neurokinin receptor, nerve growth factor, neurogenic inflammation and morphology of mast cells, were compared in sun-exposed vs. sun-protected skin quantitatively and qualitatively. Results: Cutaneous neurogenic factors associated with photoageing were characterized by a significant increase in the densities of dermal and intraepidermal nerve fibres, a correlation between epidermal innervation and the severity of photodamage, increases in the number of neuropeptidergic sensory nerve fibres in the dermis and in tissue levels of sensory neuropeptides, increases in the content of nerve growth factor, reduced expression of neurokinin receptor 1 by epidermal keratinocytes and by vascular endothelial cells and a tachykinin-specific reduction of cutaneous neurogenic inflammation. Mast cells in photodamaged skin showed several characteristic morphological features, including various degrees of activation and an intimate association with fibroblasts, which were distinct from those in sun-protected skin. Furthermore, mast cells in photodamaged skin possessed larger amounts of substance P within their granules than did those in sun-protected skin. Conclusions: These findings document for the first time characteristic alterations of cutaneous neurogenic factors in photodamaged skin and suggest that the cutaneous nervous system may be involved in photoageing processes.
文摘[Objective]The aim was to study the effects of sunflower artificial aging on seed vigor and physiological characteristics.[Method] The varieties of seed germination capacity,vigor of germination,germination index,vigor index,peroxidase（POD） activity,superoxide dismutase（SOD） activity and malondialdehyde（MDA） content for four sunflower germplasms such as＇SunM20＇,＇Deep Purple Minle＇,＇Da San Kui Hua 4＇and＇Ji Kui 24＇were studied under high temperature and high humidity conditions（100% RH,45 ℃） for different days（0 d,2 d,4 d,6 d,8 d,10 d）.[Result]The result showed that the germination capacity,vigor of germination,germination index,vigor index,POD activity,SOD activity declined gradually with the increase of seed aging days,whereas MDA content enhanced by degrees;The diggerences of resistance to artifical aging existed among the four accessions,＇SunM20＇was the most resistant one,and exhibited the strongest seed vigor,highest activities of two protective enzyme（POD,SOD） and lowest content of MDA at the uniform condition,moreover,the seed vigor and protective enzyme activities of＇SunM20＇changed slowest among the four materials during the aging process.[Conclusion]The distinct reduction of POD,SOD activities maybe the main reasons for the decrease of sunflower seed vigor at the artificial aging,and the gradual accumulation of a few MDA accelerated seeds aging.
基金Supported by Natural Science Foundation of Hainan Province(20163129)
文摘Reasons causing or accelerating seed aging are mainly damage of mem- branes, DNA and proteins, decline of protein synthesis capacity and excessive ac- cumulation of reactive oxygen species. With the application of natural aging or artifi- cial aging methods, it was reported that quantitative trait loci （QTLs） of seed stora- bility in rice were widely distributed on the chromosomes except the 10th chromo- some. In this paper, we reviewed the progresses in the research on physiological- biochemical and genetic mechanisms of seed aging, and analyzed the existing problems and developing prospect in molecular breeding of rice with improved seed storability, in order to provide reference for the basic research and genetic improve- ment of rice seed storabUity.
文摘Background: The majority of skin changes associated with ageing are caused by photoageing and reflect cumulative sun exposure. Although the actinic damage plays a major role in skin pigmentation, it is also important to examine the effects of chronological cellular ageing on the pigmentation. The chief cellular components of the skin other than melanocytes are keratinocytes and fibroblasts, and the influences of age-related changes in those cells on skin pigmentation have not been elucidated. Objective: To clarify the effects of cellular ageing of keratinocytes and fibroblasts on age-related skin pigmentation. Methods: Using ELISA analysis, we measured the level of melanogenic cytokines secreted by cultured keratinocytes and fibroblasts derived from skin of various chronological ages. We also compared the cytokine secretion by cultured keratinocytes between the second and fifth cultures. Results: There was no correlation between age and hepatocyte growth factor (HGF), stem cell factor (SCF), and basic fibroblast growth factor (b-FGF) secretion by fibroblasts. On the other hand, a significant positive correlation existed between age and interleukin ((IL)- 1α secretion (R2 = 0.50, P = 0.002), and a relatively weak correlation existed between age and endothelin- 1(ET- 1) secretion (R2 = 0.17,P = 0.051, not significant). The IL- 1α secretion by keratinocytes was significantly increased in the fifth cultures compared with the second cultures (P < 0.005). Conclusions: These findings suggest that IL- 1α secretion increases as cells grow older, and the increased secretion of IL- 1α by aged keratinocytes may stimulate HGF production in dermal fibroblasts paracrinely and ET- 1 production in keratinocytes autocrinely, which stimulates melanocyte proliferation and induces an increase of tyrosinase activity in melanocytes. Because IL- 1α is a primary mediator that responds to inflammation and injury, the transcription of genes involved in skin inflammation may be persistently induced in the aged skin. Thus the increased secretion of IL- 1α by aged keratinocytes in the aged skin may play a role in the accentuated cutaneous pigmentation and other skin ageing.
