Exposure of skin to solar ultraviolet（UV） radiation induces photo-damage.Ultraviolet B（UVB） is the major component of UV radiation which induces the production of reactive oxygen species（ROS） and plays an impor-...Exposure of skin to solar ultraviolet（UV） radiation induces photo-damage.Ultraviolet B（UVB） is the major component of UV radiation which induces the production of reactive oxygen species（ROS） and plays an impor-tant role in photo-damage.Hydrogen gas reduces ROS and alleviates inflammation.In this study,we sought to demonstrate that hydrogen-rich saline has the effect on skin injuries caused by UVB radiation.UVB radiation was irradiated on female C57BL/6 rats to induce skin injury.Hydrogen-rich saline and nitrogen-rich saline were ad-ministered to rats by intraperitoneal injection.Skin damage was detected by microscope after injury.UVB radia-tion had a significant affection in tumor necrosis factor alpha,interleukin（IL）-1β and IL-6 levels,tissue superox-ide dismutase,malondialdehyde and nitric oxide activity.Hydrogen-rich saline had a protective effect by altering the levels of these markers and relieved morphological skin injury.Hydrogen-rich saline protected against UVB radiation injury,possibly by reducing inflammation and oxidative stress.展开更多
VAR2 is an integral thylakoid membrane protein and a member of the versatile FtsH class of metalloproteases in prokaryotes and eukaryotes. Recessive mutations in the VAR2 locus give rise to variegated plants （var2） ...VAR2 is an integral thylakoid membrane protein and a member of the versatile FtsH class of metalloproteases in prokaryotes and eukaryotes. Recessive mutations in the VAR2 locus give rise to variegated plants （var2） that contain white sectors with abnormal plastids and green sectors with normal-appearing chloroplasts. In a continuing effort to isolate second-site suppressors of var2 variegation, we characterize in this report ems2505, a suppressor strain that has a virescent phenotype due to a missense mutation in At4g28590, the gene for a pioneer protein. We designated this gene SVR4 （for SUPPRESSOR OF VARIEGATION4） and the mutant allele in ems2505 as svr4-1. We demonstrate that SVR4 is located in chloroplasts and that svr4-1 single mutants are normal with respect to chloroplast anatomy and thylakoid membrane protein accumulation. However, they are modestly impaired in several aspects of photochemistry and have enhanced non-photochemical quenching （NPQ） capacity. A T-DNA insertion allele of SVR4, svr4-2, is seedling-lethal due to an early blockage of chloroplast development. We conclude that SVR4 is essential for chloroplast biogenesis, and hypothesize that SVR4 mediates some aspect of thylakoid structure or function that controls NPQ. We propose that in the suppressor strain, photoinhibitory pressure caused by a lack of VAR2 is ameliorated early in chloroplast development by enhanced NPQ capacity caused by reduced SVR4 activity. This would result in an increase in the number of chloroplasts that are able to surmount a threshold necessary to avoid photo-damage and thereby develop into functional chloroplasts.展开更多
文摘Exposure of skin to solar ultraviolet（UV） radiation induces photo-damage.Ultraviolet B（UVB） is the major component of UV radiation which induces the production of reactive oxygen species（ROS） and plays an impor-tant role in photo-damage.Hydrogen gas reduces ROS and alleviates inflammation.In this study,we sought to demonstrate that hydrogen-rich saline has the effect on skin injuries caused by UVB radiation.UVB radiation was irradiated on female C57BL/6 rats to induce skin injury.Hydrogen-rich saline and nitrogen-rich saline were ad-ministered to rats by intraperitoneal injection.Skin damage was detected by microscope after injury.UVB radia-tion had a significant affection in tumor necrosis factor alpha,interleukin（IL）-1β and IL-6 levels,tissue superox-ide dismutase,malondialdehyde and nitric oxide activity.Hydrogen-rich saline had a protective effect by altering the levels of these markers and relieved morphological skin injury.Hydrogen-rich saline protected against UVB radiation injury,possibly by reducing inflammation and oxidative stress.
文摘VAR2 is an integral thylakoid membrane protein and a member of the versatile FtsH class of metalloproteases in prokaryotes and eukaryotes. Recessive mutations in the VAR2 locus give rise to variegated plants （var2） that contain white sectors with abnormal plastids and green sectors with normal-appearing chloroplasts. In a continuing effort to isolate second-site suppressors of var2 variegation, we characterize in this report ems2505, a suppressor strain that has a virescent phenotype due to a missense mutation in At4g28590, the gene for a pioneer protein. We designated this gene SVR4 （for SUPPRESSOR OF VARIEGATION4） and the mutant allele in ems2505 as svr4-1. We demonstrate that SVR4 is located in chloroplasts and that svr4-1 single mutants are normal with respect to chloroplast anatomy and thylakoid membrane protein accumulation. However, they are modestly impaired in several aspects of photochemistry and have enhanced non-photochemical quenching （NPQ） capacity. A T-DNA insertion allele of SVR4, svr4-2, is seedling-lethal due to an early blockage of chloroplast development. We conclude that SVR4 is essential for chloroplast biogenesis, and hypothesize that SVR4 mediates some aspect of thylakoid structure or function that controls NPQ. We propose that in the suppressor strain, photoinhibitory pressure caused by a lack of VAR2 is ameliorated early in chloroplast development by enhanced NPQ capacity caused by reduced SVR4 activity. This would result in an increase in the number of chloroplasts that are able to surmount a threshold necessary to avoid photo-damage and thereby develop into functional chloroplasts.
