In the last three decades much researchhas been carried out to investigate the biologicaleffects of a thinning stratospheric ozone layeraccompanied by an enhanced level of solarultraviolet-B radiation at the Earth’s ...In the last three decades much researchhas been carried out to investigate the biologicaleffects of a thinning stratospheric ozone layeraccompanied by an enhanced level of solarultraviolet-B radiation at the Earth’s surface.Enhanced UV-B radiation affects ecosystems in manyways directly and indirectly. The responses can bebiochemical, physiological, morphological oranatomical, and the direction of the response can varybetween different species, communities andecosystems. In this paper we firstly introduce generalconcepts, and methods for measuring the ecologicaleffects of UV-B radiation. Secondly, we provide anoverview interpretation of the effects of enhancedUV-B on terrestrial ecosystems from recent studies.These studies include effects of UV-B on growth andreproduction, composition of communities,competitive balance, decomposition of litter, andinteractions with other factors etc. Finally, werecommend future research directions to identify theeffects of elevated UV-B radiation on ecosystems inChina.展开更多
We report the effect of UVoB irradiation （9.6 kJ m-2 day^-） on interspecific competition between two species of macroalgae, Ulva pertusa （U） and Grateloupiafilicina （G）, in co-culture. Growth of U. pertusa and G...We report the effect of UVoB irradiation （9.6 kJ m-2 day^-） on interspecific competition between two species of macroalgae, Ulva pertusa （U） and Grateloupiafilicina （G）, in co-culture. Growth of U. pertusa and G. filicina was inhibited by UV-B irradiation in mono-culture and specific growth rate （μ） declined as a result. Interspecific competition between U. pertusa and G filicina was closely related to the initial weights when co-cultured. When initial ratios of U. pertusa （U） to G filicina （G） were U：G=I.2：I and 1：1, U. pertusa was the dominant algae. When the initial U：G ratio was 1：1.2, G. filicina was competitively dominant in the earlier stage, but U. pertusa grew faster, superseding G. filicina in the later stage. At initial ration U：G = 1：1.4, G. filicina was predominant. Under UV-B irradiation, the competitive ability of G filicina was weakened and the interspecific competitive balance favored U. pertusa, which suggests that G. filicina was more sensitive to UV-B irradiation. We also probed the potential allelopathic effects between the two species, which led to mutual growth inhibition.展开更多
The atmosphere protects humans, plants, ani- mals, and microorganisms from damaging doses of ultra- violet-B （UVB） solar radiation （280-320 nm） because it modifies the UVB reaching the Earth＇s surface. This modif...The atmosphere protects humans, plants, ani- mals, and microorganisms from damaging doses of ultra- violet-B （UVB） solar radiation （280-320 nm） because it modifies the UVB reaching the Earth＇s surface. This modification is a function of the solar radiation＇s path length through the atmosphere and the amount of each attenuator along the path length. The path length is deter- mined by solar zenith angle （SZA）. The present work ex- plains the dependence of hemispherical transmittance of UVB on SZA. The database used consists of five years of hourly UVB and global solar radiation measurements. From 2001 to 2005, the South Valley University （SVU） meteorological research station （26.20°N, 32.75°E） car- ried out these measurements on a horizontal surface. In addition, the corresponding extraterrestrial UVB （UVBe^d and broadband solar radiation （Gext） were estimated. Consequently, the hemispherical transmittance of UVB （KtuvB） and the hemispherical transmittance of global solar radiation （Kt） were estimated. Furthermore, the UVB redaction due to the atmosphere was evaluated. An analy- sis of the dependence between KtuvB and SZA at different ranges of Kt was performed. A functional dependence between KtuvB and SZA （KtuvB=-a（SZA）＋b） for very narrow Kt-ranges （width of ranges was 0.01） was devel- oped. The results are discussed, and the sensitivity of AKtuvB to △SZA for very narrow Kt-ranges was studied. It was found that the sensitivity of △KtUVB to ASZA slightly increases with increased Kt, which means KtuvB is sensi- tive to SZA as Kt increases. The maximum correlation （R） between KtuvB and SZA was equal to -0.83 for Kt= 0.76.展开更多
To investigate the protective effect of epigallocatechin gallate （EGCG） on the immune function of dendritic cells （DCs） after ultraviolet B irradiation （UVB） and its underlying mechanisms, the monocytes were iso...To investigate the protective effect of epigallocatechin gallate （EGCG） on the immune function of dendritic cells （DCs） after ultraviolet B irradiation （UVB） and its underlying mechanisms, the monocytes were isolated from peripheral blood and cultivated into DCs with cytokines, such as GM-CSF and IL-4. DCs were harvested after cultivation for 7 d and subjected to irradiation with different dosages of UVB. Then, 200 μg/ml of EGCG were added in certain groups immediately after irradiation. DCs simply treated with UVB or treated with both UVB and EGCG were co-cultured with lymphocytes, and MTT assay was used to detect the ability of DCs to stimulate proliferation of lymphocytes. Surface markers CDS0, CD86, HLA-DR and CD40 were detected by flow cytometry, and the levels of IL-10 and IL-12 secreted from DCs 2d h after cultivation were measured by ELISA. It was demonstrated that UVB irradiation could inhibit the ability of DCs to stimulate the proliferation of lymphocytes and surface expressions of CDS0, CD86, HLA-DR and CD40 on DCs in a dose-dependent manner. The inhibition rate of DCs was improved to some extent after treatment with 200μg/ml of EGCG. When the concentra- tion of EGCG exceeded 100 μg/ml, the enhancing effect of EGCG on the expression of the co-stimulating molecules on DCs could be demonstrated in a dose-dependent manner. UVB showed no significant influence on the secretion of IL-10 and IL-12 from DCs, while EGCG could down-regulate the secretion level of IL-12 and up-regulate that of IL-10. It is concluded that EGCG can antagonize the inhibitory effect on DCs induced by UVB irradiation. This function has some relationship with its protecting effect of the expression of the co-stimulating molecule on the surface of DCs and the secretion level of IL-10 and IL-12.展开更多
基金the State Key Basic Research and Development Plan(G2000046802-05)the Chinese Academy of Sciencesfor Innovation Key Project(KSCX1-07-02-02)+1 种基金National Tackle-Key-Problem Project(2001BA606A-05-01) the"Western Light”Project of Chinese Academy of Sciences for Talent Plan.
文摘In the last three decades much researchhas been carried out to investigate the biologicaleffects of a thinning stratospheric ozone layeraccompanied by an enhanced level of solarultraviolet-B radiation at the Earth’s surface.Enhanced UV-B radiation affects ecosystems in manyways directly and indirectly. The responses can bebiochemical, physiological, morphological oranatomical, and the direction of the response can varybetween different species, communities andecosystems. In this paper we firstly introduce generalconcepts, and methods for measuring the ecologicaleffects of UV-B radiation. Secondly, we provide anoverview interpretation of the effects of enhancedUV-B on terrestrial ecosystems from recent studies.These studies include effects of UV-B on growth andreproduction, composition of communities,competitive balance, decomposition of litter, andinteractions with other factors etc. Finally, werecommend future research directions to identify theeffects of elevated UV-B radiation on ecosystems inChina.
基金Supported by the National Natural Science Foundation of China(No.30270258)the Natural Science Foundation of Shandong Province(No.2007ZRB01903)
文摘We report the effect of UVoB irradiation （9.6 kJ m-2 day^-） on interspecific competition between two species of macroalgae, Ulva pertusa （U） and Grateloupiafilicina （G）, in co-culture. Growth of U. pertusa and G. filicina was inhibited by UV-B irradiation in mono-culture and specific growth rate （μ） declined as a result. Interspecific competition between U. pertusa and G filicina was closely related to the initial weights when co-cultured. When initial ratios of U. pertusa （U） to G filicina （G） were U：G=I.2：I and 1：1, U. pertusa was the dominant algae. When the initial U：G ratio was 1：1.2, G. filicina was competitively dominant in the earlier stage, but U. pertusa grew faster, superseding G. filicina in the later stage. At initial ration U：G = 1：1.4, G. filicina was predominant. Under UV-B irradiation, the competitive ability of G filicina was weakened and the interspecific competitive balance favored U. pertusa, which suggests that G. filicina was more sensitive to UV-B irradiation. We also probed the potential allelopathic effects between the two species, which led to mutual growth inhibition.
基金supported by the Deanship of Scientific Research from King Saud University
文摘The atmosphere protects humans, plants, ani- mals, and microorganisms from damaging doses of ultra- violet-B （UVB） solar radiation （280-320 nm） because it modifies the UVB reaching the Earth＇s surface. This modification is a function of the solar radiation＇s path length through the atmosphere and the amount of each attenuator along the path length. The path length is deter- mined by solar zenith angle （SZA）. The present work ex- plains the dependence of hemispherical transmittance of UVB on SZA. The database used consists of five years of hourly UVB and global solar radiation measurements. From 2001 to 2005, the South Valley University （SVU） meteorological research station （26.20°N, 32.75°E） car- ried out these measurements on a horizontal surface. In addition, the corresponding extraterrestrial UVB （UVBe^d and broadband solar radiation （Gext） were estimated. Consequently, the hemispherical transmittance of UVB （KtuvB） and the hemispherical transmittance of global solar radiation （Kt） were estimated. Furthermore, the UVB redaction due to the atmosphere was evaluated. An analy- sis of the dependence between KtuvB and SZA at different ranges of Kt was performed. A functional dependence between KtuvB and SZA （KtuvB=-a（SZA）＋b） for very narrow Kt-ranges （width of ranges was 0.01） was devel- oped. The results are discussed, and the sensitivity of AKtuvB to △SZA for very narrow Kt-ranges was studied. It was found that the sensitivity of △KtUVB to ASZA slightly increases with increased Kt, which means KtuvB is sensi- tive to SZA as Kt increases. The maximum correlation （R） between KtuvB and SZA was equal to -0.83 for Kt= 0.76.
文摘To investigate the protective effect of epigallocatechin gallate （EGCG） on the immune function of dendritic cells （DCs） after ultraviolet B irradiation （UVB） and its underlying mechanisms, the monocytes were isolated from peripheral blood and cultivated into DCs with cytokines, such as GM-CSF and IL-4. DCs were harvested after cultivation for 7 d and subjected to irradiation with different dosages of UVB. Then, 200 μg/ml of EGCG were added in certain groups immediately after irradiation. DCs simply treated with UVB or treated with both UVB and EGCG were co-cultured with lymphocytes, and MTT assay was used to detect the ability of DCs to stimulate proliferation of lymphocytes. Surface markers CDS0, CD86, HLA-DR and CD40 were detected by flow cytometry, and the levels of IL-10 and IL-12 secreted from DCs 2d h after cultivation were measured by ELISA. It was demonstrated that UVB irradiation could inhibit the ability of DCs to stimulate the proliferation of lymphocytes and surface expressions of CDS0, CD86, HLA-DR and CD40 on DCs in a dose-dependent manner. The inhibition rate of DCs was improved to some extent after treatment with 200μg/ml of EGCG. When the concentra- tion of EGCG exceeded 100 μg/ml, the enhancing effect of EGCG on the expression of the co-stimulating molecules on DCs could be demonstrated in a dose-dependent manner. UVB showed no significant influence on the secretion of IL-10 and IL-12 from DCs, while EGCG could down-regulate the secretion level of IL-12 and up-regulate that of IL-10. It is concluded that EGCG can antagonize the inhibitory effect on DCs induced by UVB irradiation. This function has some relationship with its protecting effect of the expression of the co-stimulating molecule on the surface of DCs and the secretion level of IL-10 and IL-12.
