BACKGROUND Acoustic radiation force impulse(ARFI)is used to measure liver fibrosis and predict outcomes.The performance of elastography in assessment of fibrosis is poorer in hepatitis B virus(HBV)than in other etiolo...BACKGROUND Acoustic radiation force impulse(ARFI)is used to measure liver fibrosis and predict outcomes.The performance of elastography in assessment of fibrosis is poorer in hepatitis B virus(HBV)than in other etiologies of chronic liver disease.AIM To evaluate the performance of ARFI in long-term outcome prediction among different etiologies of chronic liver disease.METHODS Consecutive patients who received an ARFI study between 2011 and 2018 were enrolled.After excluding dual infection,alcoholism,autoimmune hepatitis,and others with incomplete data,this retrospective cohort were divided into hepatitis B(HBV,n=1064),hepatitis C(HCV,n=507),and non-HBV,non-HCV(NBNC,n=391)groups.The indexed cases were linked to cancer registration(1987-2020)and national mortality databases.The differences in morbidity and mortality among the groups were analyzed.RESULTS At the enrollment,the HBV group showed more males(77.5%),a higher prevalence of prediagnosed hepatocellular carcinoma(HCC),and a lower prevalence of comorbidities than the other groups(P<0.001).The HCV group was older and had a lower platelet count and higher ARFI score than the other groups(P<0.001).The NBNC group showed a higher body mass index and platelet count,a higher prevalence of pre-diagnosed non-HCC cancers(P<0.001),especially breast cancer,and a lower prevalence of cirrhosis.Male gender,ARFI score,and HBV were independent predictors of HCC.The 5-year risk of HCC was 5.9%and 9.8%for those ARFI-graded with severe fibrosis and cirrhosis.ARFI alone had an area under the receiver operating characteristic curve(AUROC)of 0.742 for prediction of HCC in 5 years.AUROC increased to 0.828 after adding etiology,gender,age,and platelet score.No difference was found in mortality rate among the groups.CONCLUSION The HBV group showed a higher prevalence of HCC but lower comorbidity that made mortality similar among the groups.Those patients with ARFI-graded severe fibrosis or cirrhosis should receive regular surveillance.展开更多
Effect of cerium (Ce^3+) on growth and photosynthesis in rape seedlings exposed to two levels of ultraviolet-B radiation (UV-B, 280 - 320 nm) was studied with hydroponics under laboratory conditions. The growth o...Effect of cerium (Ce^3+) on growth and photosynthesis in rape seedlings exposed to two levels of ultraviolet-B radiation (UV-B, 280 - 320 nm) was studied with hydroponics under laboratory conditions. The growth of rape seedlings exposed to two levels of UV-B irradiation (0.15 and 0.35 W· m^-2/T2) was both heavily restrained. The aboveground growth indices including stem (plant) height, leaf number, leaf area, leaf fresh/dry weight and stem fresh/dry weight were obviously decreased by 13.2% - 44.1% (T1) and 21 .4% - 49.3% (T2). Compared to CK, and except active absorption area of roots, the belowground indices main root length, root volume and fresh/dry weight by 14.1% -35.6% (T1) and 20.3% - 42.6% (T2), respectively. For Ce + UV-B treatments, the aboveground and belowground growth indices were decreased by 4.1% - 23.6%, 5.2% -23.3% (Ce+T1) and 10.8% -28.4%, 7.0% -27.8% (Ce +T2), lower than those of UV-B treatments mentioned above. These results show that Ce has protective effect on plant against injury of UV-B radiation. Furthermore, the protective effect of Ce on seedlings exposed to T1 level of UV-B radiation is superior to T2 level. Chlorophyll content, net photosynthesis rate, transpiration rate, stomatal conductance and water use efficiency in UV-B treatments decrease dramatically, whereas intercellular CO2 concentration increases. Although these indices in Ce + UV-B treatments decrease compared with those of CK, the decrease in Ce + UV-B treatments are lower than those in UV-B treatment. This phenomenon indicates that the ecophysiological protective effect of Ce is based on improving photosynthesis in plants. The dynamic curves of photosynthesis indices show that the course of light-repair is shortened and the injury to rape seedlings by UV-B radiation stress is alleviated by Ce.展开更多
The effect of La on flavonoids, chlorophyll contents, and phenylalanine ammonia-lyase (PAL) activity in soybean seedlings under supplementary ultraviolet-B radiation (UV-B, 280 - 320 nm) was studied. The results s...The effect of La on flavonoids, chlorophyll contents, and phenylalanine ammonia-lyase (PAL) activity in soybean seedlings under supplementary ultraviolet-B radiation (UV-B, 280 - 320 nm) was studied. The results show that PAL activity, contents of flavonoids and chlorophyll in the plants pretreated with La (20 mg·L^- 1 ) are higher than those in CK. UV-B radiation could result in an increase in flavonoid content and PAL activity, associated with a decrease in chlorophyll content. However, the increase in the range of PAL activity and flavonoid content in UV-B treatment are lesser than those in the La treatment. The changes of flavonoid contents and PAL activity in La + UV-B treatment are similar to those in UV-B treatment, and the increase in their range is higher than those in UV-B treatment. This shows that La can enhance the resistance of soybean seedling to UV-B radiation and alleviate the damage of UV-B radiation by increasing flavonoid content, chlorophyll content, and PAL activity.展开更多
Effect of cerium (Ce^3+) on the growth, photosynthesis and antioxidant enzyme system in rape seedlings (Brassica juncea L.) exposed to two levels of UV-B radiation (T1: 0.15 W/m^2 and T2:0.35 W/m^2) was studi...Effect of cerium (Ce^3+) on the growth, photosynthesis and antioxidant enzyme system in rape seedlings (Brassica juncea L.) exposed to two levels of UV-B radiation (T1: 0.15 W/m^2 and T2:0.35 W/m^2) was studied by hydroponics under laboratory conditions. After 5 d of UV-B treatment, the aboveground growth indices were obviously decreased by 13.2%-44. 1%(T1) and 21.4%-49.3% (T2), compared to CK, and except active absorption area of roots, the belowground indices by 14.1%-35.6%(T1) and 20.3%-42.6% (T2). For Ce+UV-B treatments, the aboveground and belowground growth indices were decreased respectively by 4.1%-23.6%, 5.2% -23.3%(Ce+T1) and 10.8%-28.4%, 7.0%-27.8%(Ce+T2), lower than those of UV-B treatments. The decrease of growth indices appeared to be the result of changes of physiological processes. Two levels of UV-B radiation induced the decrease in chlorophyll content, net photosynthesis rate, transpiration rate, stomatal conductance and water use efficiency by 11.2%-25.9%(T1) and 20.9%- 56.9%(T2), whereas increase in membrane permeability and activities of antioxidant enzymes including superoxide dismutase(SOD), catalase (CAT) and peroxidase (POD) by 6.9%, 22.8%, 21.5%, 9.5%(T1) and 36.6%, 122.3%, 103.5%, 208.9%(T2), respectively. The reduction of the photosynthetic parameters in Ce+UV-B treatments was lessened to 3.2%-13.8%(Ce+T1) and 4.9%-27.6%(Ce+T2), and the increase of membrane permeability and activities of antioxidant enzymes except POD in the same treatments were lessened to 2.4%, 8.4%, 6.6%(Ce+T1) and 30.1%, 116.7%, 75.4%(Ce+T2). These results indicate that the regulative effect of Ce on photosynthesis and antioxidant enzymatic function is the ecophysiological basis of alleviating the suppression of UV-B radiation on growth of seedlings. Furthermore, the protective effect of Ce on seedlings exposed to TI level of UV-B radiation is superior to T2 level.展开更多
Effects of cerium (Ce^3+) on photosynthetic characteristics were investigated by hydroponics under laboratory conditions when soybean seedlings were exposed to two levels of supplementary UV-B radiation. UV-B radia...Effects of cerium (Ce^3+) on photosynthetic characteristics were investigated by hydroponics under laboratory conditions when soybean seedlings were exposed to two levels of supplementary UV-B radiation. UV-B radiation badly inhibited the photosynthesis in soybean seedling, leading to a reduction in net photosynthetic rate (Pn), Hill reaction activity, light saturated photosynthetic rate (Ps) and apparent quanta yield (AQY), as well as the CO2 and light saturated photosynthetic rate (Pro) and carboxulation efficiency (CE). On the contrary, Ce obviously promoted the photosynthesis of plants by increasing Hill reaction activity, accelerating electron transport and photophosphorylation, and enhancing carboxylation efficiency. For Ce+UV-B treatments, the values of photosynthetic parameters were still lower than those of the control, but obviously higher than those of UV-B treatment. The results indicated that Ce alleviated the inhibition of UV-B radiation on the photosynthesis in soybean seedling to a certain extent. In correlating of Pn with Hill activity, AQY and CE, we found that the changes of photosynthetic rate were mainly influenced by the regulating effect of Ce on Hill activity and AQY at low level (0.15 W/m^2) of UV-B radiation, but were dominated by the regulating effect of Ce on CE at high level (0.45 W/m^2). Thus, Ce could regulate many aspects in photosynthesis of soybean seedling under UV-B stress. The regulating mechanism was close related with the dosage of UV-B radiation.展开更多
Effects of cerium (Ce^3+ ) on membranous protective enzymes in rape seedlings exposed to two levels of enhanced uhraviolet-B radiation (UV-B, 280 - 320 nm) were studied by hydroponics in the laboratory. The resul...Effects of cerium (Ce^3+ ) on membranous protective enzymes in rape seedlings exposed to two levels of enhanced uhraviolet-B radiation (UV-B, 280 - 320 nm) were studied by hydroponics in the laboratory. The results show that the chlorophyll content decreases and membrane permeability increases in the leaves under UV-B irradiation with an intensity of 0.15 and 0.35 W·m^-2. The activities of SOD, CAT and POD are first increased and then decreased in leaves exposed to a low level of UV-B radiation. POD activity in leaves exposed to a high level of UV-B radiation is enhanced constantly. The sensitivities of these enzymes to UV-B radiation are SOD 〉 CAT 〉 POD. The injury by UV-B radiation on the functions of protective enzymes is lightened, their ability to scavenge radicals is improved, and the membrane permeability is maintained by Ce. Furthermore, the protective effect of cerium is more obvious in plants exposed to low levels of UV-B radiation than to high levels of it. Accordingly, all results prove that the protective effect of Ce on plants under UV-B radiation is realized through the protective system of plants.展开更多
Effects of the simulated acid rain(AR) and ultraviolet-B(UV-B, 280-320 nm) radiation with a single or two ways simultaneously (AR + UV-B) on the antioxidant enzyme and photosynthesis of the rape seedlings were ...Effects of the simulated acid rain(AR) and ultraviolet-B(UV-B, 280-320 nm) radiation with a single or two ways simultaneously (AR + UV-B) on the antioxidant enzyme and photosynthesis of the rape seedlings were investigated by the hydroponic culture. The results of static experiment indicated that the tolerance of rape seedling to single stress(AR or UV-B) is stronger than that to dual stresses(AR + UV-B). Furthermore, the dual stresses had additive effect on catalase activity, and a synergistic effect on MDA content, net photosynthesis rate, water use efficiency as well as intercellular CO2 concentration. Meanwhile, it has an independent effect on chlorophyll content, stomatal conductance, and transpiration rate as well as membrane permeability. During 64 h restoration course, the dynamic change in the curves of physiological and biochemical indices were not identical, and none of them show a simple linear variation. According to the static and dynamic experiments, it was found that a responsive sequence of catalase activity, membrane permeability, MDA content and photosynthetic characteristics to the above-mentioned stresses was as follows: AR + UV-B 〉 UV-B 〉 AR.展开更多
To explore the wheat seedling development and physiological responses under copper contamination and enhanced ultraviolet-B (UV-B) irradiation, 10 mg·L-1 CuCl2 solution was irrigated to Triticum aestivum L. cv. L...To explore the wheat seedling development and physiological responses under copper contamination and enhanced ultraviolet-B (UV-B) irradiation, 10 mg·L-1 CuCl2 solution was irrigated to Triticum aestivum L. cv. Linyuan 2069 one day after germination with or without ultraviolet-B (10.08 kJ m-2·d-1) light exposure, respectively. The results showed that Cu2+ and UV-B caused various adverse effects on wheat seedling development. Cu2+ hindered root development by significantly reducing root number, while UV-B dwarfed seedling height and decreased the leaf length. Chlorophyll content and activity of ATPase in thylakoid membrane of wheat leaves dropped significantly under enhanced UV-B while the activity of ATPase in plasma membrane of seedling root was significantly decreased in Cu2+ group. Relative electric conductivity of leaves significantly increased in both Cu2+ and UV-B groups, so did the biomass. We also observed that combined Cu2+ and UV-B showed more adverse effects on wheat seedlings than either of them alone except for root growth.展开更多
Wheat (Triticum aestivum), as a kind of important economic crop cultured in the Northern China, is affected by present-day enhanced ultraviolet-B (UV-B) radiation. To get the information of the impact by UV-B radiatio...Wheat (Triticum aestivum), as a kind of important economic crop cultured in the Northern China, is affected by present-day enhanced ultraviolet-B (UV-B) radiation. To get the information of the impact by UV-B radiation on it, the proteins of wheat (Jin mai NO.8) leaves, which were divided into the normal light group (CK) and UV-B radiation group (B), were extracted and ran at SDS-PAGE at different treatment days (5, 6, 7). The proteins were also analyzed by run two-dimensional gel electrophoresis (2-DE), which allowed the identification of some significantly different gel spots. The proteins spots were further verified by Matrix-Assisted Laser Desorption/lonization-time of Flight Mass Spectrometry. The results showed: 1) the enhanced UV-B affects the growth of the wheat, as the visual changes appear on the sixth day;2) the proteins expressions between the B group and the CK group were remarkably different on the sixth day;3) the proteins of wheat leaves of the sixth day were further analyzed by 2-DE revealed that twenty-one protein points were identificated between the B group and the CK group. Among these twenty-one proteins, six proteins of them were up-regulated and twelve proteins of them were down-regulated, three new proteins were expressed only in the B group. Three proteins among six proteins, which were up-regulated, were further verified as RuBisCo large subunit binding protein;SOD;Calmodulin. The result indicates wheat could improve genes encoding proteins in their leaves and protect themselves, when enhanced UV-B affects the growth of the wheat.展开更多
We explored the use of exogenous nitric oxide (NO) on alleviating effects of UV-B light on winter wheat development. Triticum aestivum L. cv. Linyou 7287 seeds were irradiated with UV-B (10.08 kJ·m–2·d–1) ...We explored the use of exogenous nitric oxide (NO) on alleviating effects of UV-B light on winter wheat development. Triticum aestivum L. cv. Linyou 7287 seeds were irradiated with UV-B (10.08 kJ·m–2·d–1) (enhanced UV-B) and watered with either water or 100 μmol·L–1 SNP solution. Plants were also watered with the SNP alone. The results showed that enhanced UV-B produced negative effects on seedling development. Leaf length decreased and seedling biomass dropped significantly compared with the control. Photochemical efficiency (Fv/Fm) dropped, and chlorophyll and carotenoid content as well as the ATPase activity declined. Content of UV-absorbing compounds and activity of the POD increased compared to the control. Application of the SNP, a NO donor partially protected wheat seedlings exposed to elevated UV-B radiation in that their leaf lengths and biomass accumulation were enhanced compared to the UV-B treatment alone. SNP also improved the contents of chlorophyll, carotenoid and UV-absorbing compounds in leaves. ATPase activity was enhanced but no influence on POD activity. Furthermore, the application of SNP alone showed a favorable effect on seedling growth compared with the control.展开更多
The distribution and morphology alterations of microfilaments and microtubules in the mesophyll cells and root-tip cells of wheat seedlings, which had been radiated by enhanced ultraviolet-B (10.08 KJ·m-2·d-...The distribution and morphology alterations of microfilaments and microtubules in the mesophyll cells and root-tip cells of wheat seedlings, which had been radiated by enhanced ultraviolet-B (10.08 KJ·m-2·d-1), were examined through the confocal laser scanning microscope (Model FV1000, Olympus, Japan). Microtubule was labeled with an indirect immunofluorescence staining method, and microfilament was labeled with fluorescein isothiocyanate-phalloidin (FITC-Ph) as probes. The results indicated that microtubules in mesophyll cells, compared with the controls, would be depolymerized significantly, and dispersed randomly showing some spots or short rods in the cytoplasm, under the enhanced UV-B radiation condition. The microtubule bundles tended to be diffused, and the fluorescence intensity of that significantly decreased. The distribution pattern of microfilaments, which usually arranged parallelly in control cells, was broken up by enhanced UV-B radiation. We further investigated the distribution and morphology of microtubules in root-tip cells during every stage of cell division, and found that these aberrant phenomena of microtubules were often associated with abnormal cell division. Our findings suggested that the distribution, morphology and structure of cytoskeleton in mesophyll cells and root-tip cells of wheat seedlings would be affected by enhanced UV-B radiation, which might be related to abnormal cell division caused by enhanced UV-B radiation as an extracellular signal.展开更多
Effect of UV - B radiation on the feeding behaviour of marine zooplankton is important to assessing the health harm of marine ecosystem due to the gradually enhanced UV - B radiation in air. However, there are a few s...Effect of UV - B radiation on the feeding behaviour of marine zooplankton is important to assessing the health harm of marine ecosystem due to the gradually enhanced UV - B radiation in air. However, there are a few studies on this topic. The feeding behavior of the rotifer, Brachionus plicatilis, under the treatment of UV - B radiation on five species of microalgae, i. e. , Chlorella sp. , Tetraselmis chuii, Isochrysis galbana Park 8701, Chaetoceros muelleri Lermumerman, and Nitzschia clostertum, was studied. The results showed that the filtering and feeding rates of the rotifer decreased significantly with the dose increase of UV - B radiation when fed with five species of microalgae respectively ( P 〈 0.05 ) which indicates UV - B radiation inhibits the feeding activities of the rotifer on microalage. The mixed culture experiments shows the rotifer preferred to feed Chlorella sp. , then C. muelleri, L galbana, N. clostertum and T. chuii in turn if without UV - B radiation. Under the highest dose of UV - B radiation treatment (2.70 kJ/m^2), the rotifer preferred to feed C. muelleri, then Chlorella sp. , N. clostertum, L galbana and T. chuii in turn. Chlorella sp. , L galbana and C. muelleri became the more favorite foods of the rotifer while T. chuii and N. clostertum became less favorite foods. The change of feeding rate and feeding selectivity of zooplankton driven by the enhanced UV - B radiation will lead to the change in the structure of phytoplankton community.展开更多
Objective:To explore the curative effect of nano-Kuiyangye on radiation esophagitis in Wistar rats,and to explore its possible mechanism.Methods:Wistar rats were irradiated locally with 30Gy rays to establish an anima...Objective:To explore the curative effect of nano-Kuiyangye on radiation esophagitis in Wistar rats,and to explore its possible mechanism.Methods:Wistar rats were irradiated locally with 30Gy rays to establish an animal model of radiation esophagitis in rats.After irradiation,nano-Kuiyangye,traditional Chinese medicine ulcer solution,Kangfuxin solution,nano-hydrotalcite matrix,and distilled water were used to intervene continuously for 7 d,during which the body weight and food intake of the rats were recorded.On day 7,blood was collected from the abdominal aorta under anesthesia,and the serum was obtained by centrifugation.The expression levels of pain-related factors prostaglandin-2(PGE-2),substance P(SP),and calcitonin gene-related peptide(CGRP)were detected by ELISA.Rats were sacrificed after blood collection,and full-length esophageal tissues were taken.Hematoxylin-eosin(HE)staining was performed to analyze the pathological changes of the rat esophagus,and Western Blotting was used to detect the expression of nuclear factor-κB(NF-κB)inflammatory protein.Results:Compared with the control group,the total food intake and body weight of the rats within 7 d after modeling were significantly decreased(P<0.05),and the expressions of pain-related factors PGE-2,SP,and CGRP were higher than those of the control group(P<0.05).,the esophageal pathological damage score increased(P<0.05),and the expression of NF-κB inflammatory protein increased(P<0.05);after treatment,the total food intake of the rats in the nano-Kuiyangye intervention group within 7 days after modeling was higher than that in other groups(P<0.05),the expressions of pain-related factors PGE-2,SP,and CGRP were lower than those in the model group(P<0.05),the esophageal pathological damage score was lower(P<0.05),and the expression of NF-κB inflammatory proteins was lower(P<0.05).Conclusion:Nano-Kuiyangye increases the food intake of rats with radiation esophagitis,reduces esophageal tissue damage,and reduces the concentration of serum pain factors;the anti-inflammatory effect of nano-Kuiyangye may be related to the reduction of NF-κB inflammatory factor levels.展开更多
The hydroponic culture experiments of soybean bean seedlings were conducted to investigate the effect of lanthanum (La) on nitrogen metabolism under two different levels of elevated UV-B radiation (UV-B, 280-320 nm...The hydroponic culture experiments of soybean bean seedlings were conducted to investigate the effect of lanthanum (La) on nitrogen metabolism under two different levels of elevated UV-B radiation (UV-B, 280-320 nm). The whole process of nitrogen metabolism involves uptake and transport of nitrate, nitrate assimilation, ammonium assimilation, amino acid biosynthesis, and protein synthesis. Compared with the control, UV-B radiation with the intensity of low level 0.15 W/m^2 and high level 0.45 W/m^2 significantly affected the whole nitrogen metabolism in soybean seedlings (p 〈 0.05). It restricted uptake and transport of NO3^-, inhibited activity of some key nitrogen-metabolism-related enzymes, such as: nitrate reductase (NR) to the nitrate reduction, glutamine systhetase (GS) and glutamine synthase (GOGAT) to the ammonia assimilation, while it increased the content of free amino acids and decreased that of soluble protein as well. The damage effect of high level of UV-B radiation on nitrogen metabolism was greater than that of low level. And UV-B radiation promoted the activity of the anti-adversity enzyme glutamate dehydrogenase (GDH), which reduced the toxicity of excess ammonia in plant. After pretreatment with the optimum concentration of La (20 mg/L), La could increase the activity of NR, GS, GOGAT, and GDH, and ammonia assimilation, but decrease nitrate and ammonia accumulation. In conclusion, La could relieve the damage effect of UV-B radiation on plant by regulating nitrogen metabolism process, and its alleviating effect under low level was better than that under the high one.展开更多
The responses of the interspecific competition between Skeletonema costatum and Heterosigma akashiwo to UV-B radiation enhancement were studied by the co-culture method. The results showed that Heterosigma akashiwo ex...The responses of the interspecific competition between Skeletonema costatum and Heterosigma akashiwo to UV-B radiation enhancement were studied by the co-culture method. The results showed that Heterosigma akashiwo exhibited inhibition on the growth of Skeletonema costatum, and with the increase of initial inoculation density of Heterosigma akashiwo, heavier inhibition on Skeletonema costatum appeared. Under different inoculation proportions, Heterosigma akashiwo could always be in predominance in competition with Skeletonema costatum. The UV-B radiation treatment could change the competition relationship between Skeletonema costatum and Heterosigma akashiwo, which could increase the competitive dominance of Skeletonema costatum and decrease the competitive dominance of Heterosigma akashiwo. When the inoculation proportions of Heterosigma akashiwo and Skeletonema costatum were H∶S=1∶4 and H∶S=1∶1,Skeletonema costatum was in predominance in this competition; however, Heterosigma akashiwo was in predominance when the inoculation proportion was H∶S=4∶1.展开更多
Enhanced UV-B(280-320 nm) radiation resulting from ozone depletion is one of global environmental problems. Not only marine organisms but also marine ecosystems can be affected by enhanced UV-B radiation. The effects ...Enhanced UV-B(280-320 nm) radiation resulting from ozone depletion is one of global environmental problems. Not only marine organisms but also marine ecosystems can be affected by enhanced UV-B radiation. The effects of UV-B radiation on interaction of macro-algae and micro-algae were investigated using Ulva pertusa Kjellman and Alexandrium tamarense as the materials in this study. The results demonstrated that UV-B radiation could inhibit the growth of Ulva pertusa and Alexandrium tamarense when they were both mono-cultured, and the growth inhibition of algae was more significant with increasing doses of UV-B radiation. Alexandrium tamarense could inhibit the growth of Ulva pertusa in mixed culture, and the growth inhibition was more significant when increasing the initial cell density. However, Ulva pertusa could inhibit the growth of Alexandrium tamarense in early phase and stimulate the growth in latter phase when they were grown in mixed culture. Lower initial cell density(10~2 cell/ml) of Alexandrium tamarense could inhibit the growth of Ulva pertusa under UV-B radiation treatment,however, with the initial cell density increasing(10~3 and 10~4 cell/ml), the growth of Ulva pertusa was stimulated under lower dose of UV-B radiation and inhibited under higher dose of UV-B radiation by Alexandrium tamarense. Compared with that in mixed culture, Ulva pertusa showed more positive inhibition to the growth of Alexandrium tamarense under UV-B radiation treatment.展开更多
We evaluated the effects of red and blue light on the repair of UV-B radiation-induced damage in tetraspores of Chondrus ocellatus Holm. Tetraspores of C. ocellatus were treated with different UV-B radiation levels(0,...We evaluated the effects of red and blue light on the repair of UV-B radiation-induced damage in tetraspores of Chondrus ocellatus Holm. Tetraspores of C. ocellatus were treated with different UV-B radiation levels(0,36,72,108,144 and 180 J/m2),and thereafter subjected to PAR,darkness,or red or blue light during a 2-h repair stage,each day for 48 days. The diameters and cellular contents of cyclobutane pyrimidine dimmers(CPDs),chlorophyll a(Chl a),phycoerythrin,and UV-B-absorbing mycosporinelike amino acids(MAAs) contents of the tetraspores were determined. Our results show that low doses of UV-B radiation(36 and 72 J/m 2) promoted the growth of C. ocellatus; however,increased UV-B radiation gradually reduced the C. ocellatus growth(greater than 72 J/m2). The MAAs(palythine and asterina-330) in C. ocellatus were detected and analyzed by LC/MS. Our results suggest that moderate red light could induce the growth of this alga in aquaculture. In addition,photorepair was inhibited by red light,so there may be some other DNA repair mechanism activated by red light. Blue light promoted the activity of DNA photolyase,greatly improving remediation efficiency. Red and blue lights were found to reduce the capacity of C. ocellatus to form MAAs. Therefore,PAR,red light,and blue light play different roles during the repair processes for damage induced by UV-B radiation.展开更多
Effect of UV-B radiation on ingesting and nutritional selecting behavior of the roifer Brachionus urceus on 5 species of microlgae were studied under controlled laboratory conditions. Restdts showed that enhanced UV-B...Effect of UV-B radiation on ingesting and nutritional selecting behavior of the roifer Brachionus urceus on 5 species of microlgae were studied under controlled laboratory conditions. Restdts showed that enhanced UV-B radiation significantly inhibited ingesting of the rotifer B. urceus when it was fed with 5 species of micro-algae (p〈0.05). The ingesting selectivity rate varied with the UV-B radiation enhancement when it was fed with 5 species micro-algal mixture. Results indicated that the enhanced UV-B radiation could affect ingesting and nutritional selectivity of B. urceus.展开更多
基金Supported by the Chang Gung Memorial Hospital and PAII Inc.(a United States subsidiary company of Ping An Insurance Group),No.SMRPG3I0011.
文摘BACKGROUND Acoustic radiation force impulse(ARFI)is used to measure liver fibrosis and predict outcomes.The performance of elastography in assessment of fibrosis is poorer in hepatitis B virus(HBV)than in other etiologies of chronic liver disease.AIM To evaluate the performance of ARFI in long-term outcome prediction among different etiologies of chronic liver disease.METHODS Consecutive patients who received an ARFI study between 2011 and 2018 were enrolled.After excluding dual infection,alcoholism,autoimmune hepatitis,and others with incomplete data,this retrospective cohort were divided into hepatitis B(HBV,n=1064),hepatitis C(HCV,n=507),and non-HBV,non-HCV(NBNC,n=391)groups.The indexed cases were linked to cancer registration(1987-2020)and national mortality databases.The differences in morbidity and mortality among the groups were analyzed.RESULTS At the enrollment,the HBV group showed more males(77.5%),a higher prevalence of prediagnosed hepatocellular carcinoma(HCC),and a lower prevalence of comorbidities than the other groups(P<0.001).The HCV group was older and had a lower platelet count and higher ARFI score than the other groups(P<0.001).The NBNC group showed a higher body mass index and platelet count,a higher prevalence of pre-diagnosed non-HCC cancers(P<0.001),especially breast cancer,and a lower prevalence of cirrhosis.Male gender,ARFI score,and HBV were independent predictors of HCC.The 5-year risk of HCC was 5.9%and 9.8%for those ARFI-graded with severe fibrosis and cirrhosis.ARFI alone had an area under the receiver operating characteristic curve(AUROC)of 0.742 for prediction of HCC in 5 years.AUROC increased to 0.828 after adding etiology,gender,age,and platelet score.No difference was found in mortality rate among the groups.CONCLUSION The HBV group showed a higher prevalence of HCC but lower comorbidity that made mortality similar among the groups.Those patients with ARFI-graded severe fibrosis or cirrhosis should receive regular surveillance.
文摘Effect of cerium (Ce^3+) on growth and photosynthesis in rape seedlings exposed to two levels of ultraviolet-B radiation (UV-B, 280 - 320 nm) was studied with hydroponics under laboratory conditions. The growth of rape seedlings exposed to two levels of UV-B irradiation (0.15 and 0.35 W· m^-2/T2) was both heavily restrained. The aboveground growth indices including stem (plant) height, leaf number, leaf area, leaf fresh/dry weight and stem fresh/dry weight were obviously decreased by 13.2% - 44.1% (T1) and 21 .4% - 49.3% (T2). Compared to CK, and except active absorption area of roots, the belowground indices main root length, root volume and fresh/dry weight by 14.1% -35.6% (T1) and 20.3% - 42.6% (T2), respectively. For Ce + UV-B treatments, the aboveground and belowground growth indices were decreased by 4.1% - 23.6%, 5.2% -23.3% (Ce+T1) and 10.8% -28.4%, 7.0% -27.8% (Ce +T2), lower than those of UV-B treatments mentioned above. These results show that Ce has protective effect on plant against injury of UV-B radiation. Furthermore, the protective effect of Ce on seedlings exposed to T1 level of UV-B radiation is superior to T2 level. Chlorophyll content, net photosynthesis rate, transpiration rate, stomatal conductance and water use efficiency in UV-B treatments decrease dramatically, whereas intercellular CO2 concentration increases. Although these indices in Ce + UV-B treatments decrease compared with those of CK, the decrease in Ce + UV-B treatments are lower than those in UV-B treatment. This phenomenon indicates that the ecophysiological protective effect of Ce is based on improving photosynthesis in plants. The dynamic curves of photosynthesis indices show that the course of light-repair is shortened and the injury to rape seedlings by UV-B radiation stress is alleviated by Ce.
基金Project supported by the National Natural Science Foundation of China (20471030)the Foundation of State PlanningCommittee (IFZ20051210)
文摘The effect of La on flavonoids, chlorophyll contents, and phenylalanine ammonia-lyase (PAL) activity in soybean seedlings under supplementary ultraviolet-B radiation (UV-B, 280 - 320 nm) was studied. The results show that PAL activity, contents of flavonoids and chlorophyll in the plants pretreated with La (20 mg·L^- 1 ) are higher than those in CK. UV-B radiation could result in an increase in flavonoid content and PAL activity, associated with a decrease in chlorophyll content. However, the increase in the range of PAL activity and flavonoid content in UV-B treatment are lesser than those in the La treatment. The changes of flavonoid contents and PAL activity in La + UV-B treatment are similar to those in UV-B treatment, and the increase in their range is higher than those in UV-B treatment. This shows that La can enhance the resistance of soybean seedling to UV-B radiation and alleviate the damage of UV-B radiation by increasing flavonoid content, chlorophyll content, and PAL activity.
基金The National Natural Science Foundation of China (No. 20471030 30570323) and the Foundation of State Planning Committee(No. GFZ040628)
文摘Effect of cerium (Ce^3+) on the growth, photosynthesis and antioxidant enzyme system in rape seedlings (Brassica juncea L.) exposed to two levels of UV-B radiation (T1: 0.15 W/m^2 and T2:0.35 W/m^2) was studied by hydroponics under laboratory conditions. After 5 d of UV-B treatment, the aboveground growth indices were obviously decreased by 13.2%-44. 1%(T1) and 21.4%-49.3% (T2), compared to CK, and except active absorption area of roots, the belowground indices by 14.1%-35.6%(T1) and 20.3%-42.6% (T2). For Ce+UV-B treatments, the aboveground and belowground growth indices were decreased respectively by 4.1%-23.6%, 5.2% -23.3%(Ce+T1) and 10.8%-28.4%, 7.0%-27.8%(Ce+T2), lower than those of UV-B treatments. The decrease of growth indices appeared to be the result of changes of physiological processes. Two levels of UV-B radiation induced the decrease in chlorophyll content, net photosynthesis rate, transpiration rate, stomatal conductance and water use efficiency by 11.2%-25.9%(T1) and 20.9%- 56.9%(T2), whereas increase in membrane permeability and activities of antioxidant enzymes including superoxide dismutase(SOD), catalase (CAT) and peroxidase (POD) by 6.9%, 22.8%, 21.5%, 9.5%(T1) and 36.6%, 122.3%, 103.5%, 208.9%(T2), respectively. The reduction of the photosynthetic parameters in Ce+UV-B treatments was lessened to 3.2%-13.8%(Ce+T1) and 4.9%-27.6%(Ce+T2), and the increase of membrane permeability and activities of antioxidant enzymes except POD in the same treatments were lessened to 2.4%, 8.4%, 6.6%(Ce+T1) and 30.1%, 116.7%, 75.4%(Ce+T2). These results indicate that the regulative effect of Ce on photosynthesis and antioxidant enzymatic function is the ecophysiological basis of alleviating the suppression of UV-B radiation on growth of seedlings. Furthermore, the protective effect of Ce on seedlings exposed to TI level of UV-B radiation is superior to T2 level.
基金The National Natural Science Foundation of China (No. 20471030, 30570323) the Foundation of State Planning Committee (No.GFZ040628, BG2005040)
文摘Effects of cerium (Ce^3+) on photosynthetic characteristics were investigated by hydroponics under laboratory conditions when soybean seedlings were exposed to two levels of supplementary UV-B radiation. UV-B radiation badly inhibited the photosynthesis in soybean seedling, leading to a reduction in net photosynthetic rate (Pn), Hill reaction activity, light saturated photosynthetic rate (Ps) and apparent quanta yield (AQY), as well as the CO2 and light saturated photosynthetic rate (Pro) and carboxulation efficiency (CE). On the contrary, Ce obviously promoted the photosynthesis of plants by increasing Hill reaction activity, accelerating electron transport and photophosphorylation, and enhancing carboxylation efficiency. For Ce+UV-B treatments, the values of photosynthetic parameters were still lower than those of the control, but obviously higher than those of UV-B treatment. The results indicated that Ce alleviated the inhibition of UV-B radiation on the photosynthesis in soybean seedling to a certain extent. In correlating of Pn with Hill activity, AQY and CE, we found that the changes of photosynthetic rate were mainly influenced by the regulating effect of Ce on Hill activity and AQY at low level (0.15 W/m^2) of UV-B radiation, but were dominated by the regulating effect of Ce on CE at high level (0.45 W/m^2). Thus, Ce could regulate many aspects in photosynthesis of soybean seedling under UV-B stress. The regulating mechanism was close related with the dosage of UV-B radiation.
文摘Effects of cerium (Ce^3+ ) on membranous protective enzymes in rape seedlings exposed to two levels of enhanced uhraviolet-B radiation (UV-B, 280 - 320 nm) were studied by hydroponics in the laboratory. The results show that the chlorophyll content decreases and membrane permeability increases in the leaves under UV-B irradiation with an intensity of 0.15 and 0.35 W·m^-2. The activities of SOD, CAT and POD are first increased and then decreased in leaves exposed to a low level of UV-B radiation. POD activity in leaves exposed to a high level of UV-B radiation is enhanced constantly. The sensitivities of these enzymes to UV-B radiation are SOD 〉 CAT 〉 POD. The injury by UV-B radiation on the functions of protective enzymes is lightened, their ability to scavenge radicals is improved, and the membrane permeability is maintained by Ce. Furthermore, the protective effect of cerium is more obvious in plants exposed to low levels of UV-B radiation than to high levels of it. Accordingly, all results prove that the protective effect of Ce on plants under UV-B radiation is realized through the protective system of plants.
文摘Effects of the simulated acid rain(AR) and ultraviolet-B(UV-B, 280-320 nm) radiation with a single or two ways simultaneously (AR + UV-B) on the antioxidant enzyme and photosynthesis of the rape seedlings were investigated by the hydroponic culture. The results of static experiment indicated that the tolerance of rape seedling to single stress(AR or UV-B) is stronger than that to dual stresses(AR + UV-B). Furthermore, the dual stresses had additive effect on catalase activity, and a synergistic effect on MDA content, net photosynthesis rate, water use efficiency as well as intercellular CO2 concentration. Meanwhile, it has an independent effect on chlorophyll content, stomatal conductance, and transpiration rate as well as membrane permeability. During 64 h restoration course, the dynamic change in the curves of physiological and biochemical indices were not identical, and none of them show a simple linear variation. According to the static and dynamic experiments, it was found that a responsive sequence of catalase activity, membrane permeability, MDA content and photosynthetic characteristics to the above-mentioned stresses was as follows: AR + UV-B 〉 UV-B 〉 AR.
文摘To explore the wheat seedling development and physiological responses under copper contamination and enhanced ultraviolet-B (UV-B) irradiation, 10 mg·L-1 CuCl2 solution was irrigated to Triticum aestivum L. cv. Linyuan 2069 one day after germination with or without ultraviolet-B (10.08 kJ m-2·d-1) light exposure, respectively. The results showed that Cu2+ and UV-B caused various adverse effects on wheat seedling development. Cu2+ hindered root development by significantly reducing root number, while UV-B dwarfed seedling height and decreased the leaf length. Chlorophyll content and activity of ATPase in thylakoid membrane of wheat leaves dropped significantly under enhanced UV-B while the activity of ATPase in plasma membrane of seedling root was significantly decreased in Cu2+ group. Relative electric conductivity of leaves significantly increased in both Cu2+ and UV-B groups, so did the biomass. We also observed that combined Cu2+ and UV-B showed more adverse effects on wheat seedlings than either of them alone except for root growth.
文摘Wheat (Triticum aestivum), as a kind of important economic crop cultured in the Northern China, is affected by present-day enhanced ultraviolet-B (UV-B) radiation. To get the information of the impact by UV-B radiation on it, the proteins of wheat (Jin mai NO.8) leaves, which were divided into the normal light group (CK) and UV-B radiation group (B), were extracted and ran at SDS-PAGE at different treatment days (5, 6, 7). The proteins were also analyzed by run two-dimensional gel electrophoresis (2-DE), which allowed the identification of some significantly different gel spots. The proteins spots were further verified by Matrix-Assisted Laser Desorption/lonization-time of Flight Mass Spectrometry. The results showed: 1) the enhanced UV-B affects the growth of the wheat, as the visual changes appear on the sixth day;2) the proteins expressions between the B group and the CK group were remarkably different on the sixth day;3) the proteins of wheat leaves of the sixth day were further analyzed by 2-DE revealed that twenty-one protein points were identificated between the B group and the CK group. Among these twenty-one proteins, six proteins of them were up-regulated and twelve proteins of them were down-regulated, three new proteins were expressed only in the B group. Three proteins among six proteins, which were up-regulated, were further verified as RuBisCo large subunit binding protein;SOD;Calmodulin. The result indicates wheat could improve genes encoding proteins in their leaves and protect themselves, when enhanced UV-B affects the growth of the wheat.
文摘We explored the use of exogenous nitric oxide (NO) on alleviating effects of UV-B light on winter wheat development. Triticum aestivum L. cv. Linyou 7287 seeds were irradiated with UV-B (10.08 kJ·m–2·d–1) (enhanced UV-B) and watered with either water or 100 μmol·L–1 SNP solution. Plants were also watered with the SNP alone. The results showed that enhanced UV-B produced negative effects on seedling development. Leaf length decreased and seedling biomass dropped significantly compared with the control. Photochemical efficiency (Fv/Fm) dropped, and chlorophyll and carotenoid content as well as the ATPase activity declined. Content of UV-absorbing compounds and activity of the POD increased compared to the control. Application of the SNP, a NO donor partially protected wheat seedlings exposed to elevated UV-B radiation in that their leaf lengths and biomass accumulation were enhanced compared to the UV-B treatment alone. SNP also improved the contents of chlorophyll, carotenoid and UV-absorbing compounds in leaves. ATPase activity was enhanced but no influence on POD activity. Furthermore, the application of SNP alone showed a favorable effect on seedling growth compared with the control.
文摘The distribution and morphology alterations of microfilaments and microtubules in the mesophyll cells and root-tip cells of wheat seedlings, which had been radiated by enhanced ultraviolet-B (10.08 KJ·m-2·d-1), were examined through the confocal laser scanning microscope (Model FV1000, Olympus, Japan). Microtubule was labeled with an indirect immunofluorescence staining method, and microfilament was labeled with fluorescein isothiocyanate-phalloidin (FITC-Ph) as probes. The results indicated that microtubules in mesophyll cells, compared with the controls, would be depolymerized significantly, and dispersed randomly showing some spots or short rods in the cytoplasm, under the enhanced UV-B radiation condition. The microtubule bundles tended to be diffused, and the fluorescence intensity of that significantly decreased. The distribution pattern of microfilaments, which usually arranged parallelly in control cells, was broken up by enhanced UV-B radiation. We further investigated the distribution and morphology of microtubules in root-tip cells during every stage of cell division, and found that these aberrant phenomena of microtubules were often associated with abnormal cell division. Our findings suggested that the distribution, morphology and structure of cytoskeleton in mesophyll cells and root-tip cells of wheat seedlings would be affected by enhanced UV-B radiation, which might be related to abnormal cell division caused by enhanced UV-B radiation as an extracellular signal.
基金This work was supported by the National Natural Science Foundation of China under contract Nos 30270258 and 40506028 the National High Technology Research and Development Program of China under contract No. 2002AA648010+2 种基金 the China Postdoctoral Science Foundation under contract No. 2005037237 the Shandong Scientific Research Encouragement Foundation for Talent Youths under contract No. 03BS120the Doctor Scientific Research Foundation of Dongying Vocational College under contract No. B J0602.
文摘Effect of UV - B radiation on the feeding behaviour of marine zooplankton is important to assessing the health harm of marine ecosystem due to the gradually enhanced UV - B radiation in air. However, there are a few studies on this topic. The feeding behavior of the rotifer, Brachionus plicatilis, under the treatment of UV - B radiation on five species of microalgae, i. e. , Chlorella sp. , Tetraselmis chuii, Isochrysis galbana Park 8701, Chaetoceros muelleri Lermumerman, and Nitzschia clostertum, was studied. The results showed that the filtering and feeding rates of the rotifer decreased significantly with the dose increase of UV - B radiation when fed with five species of microalgae respectively ( P 〈 0.05 ) which indicates UV - B radiation inhibits the feeding activities of the rotifer on microalage. The mixed culture experiments shows the rotifer preferred to feed Chlorella sp. , then C. muelleri, L galbana, N. clostertum and T. chuii in turn if without UV - B radiation. Under the highest dose of UV - B radiation treatment (2.70 kJ/m^2), the rotifer preferred to feed C. muelleri, then Chlorella sp. , N. clostertum, L galbana and T. chuii in turn. Chlorella sp. , L galbana and C. muelleri became the more favorite foods of the rotifer while T. chuii and N. clostertum became less favorite foods. The change of feeding rate and feeding selectivity of zooplankton driven by the enhanced UV - B radiation will lead to the change in the structure of phytoplankton community.
基金Beijing Administration of Traditional Chinese Medicine Major Difficult Diseases Clinical Collaboration Project of Traditional Chinese and Western Medicine (No.2019-ZX-005)。
文摘Objective:To explore the curative effect of nano-Kuiyangye on radiation esophagitis in Wistar rats,and to explore its possible mechanism.Methods:Wistar rats were irradiated locally with 30Gy rays to establish an animal model of radiation esophagitis in rats.After irradiation,nano-Kuiyangye,traditional Chinese medicine ulcer solution,Kangfuxin solution,nano-hydrotalcite matrix,and distilled water were used to intervene continuously for 7 d,during which the body weight and food intake of the rats were recorded.On day 7,blood was collected from the abdominal aorta under anesthesia,and the serum was obtained by centrifugation.The expression levels of pain-related factors prostaglandin-2(PGE-2),substance P(SP),and calcitonin gene-related peptide(CGRP)were detected by ELISA.Rats were sacrificed after blood collection,and full-length esophageal tissues were taken.Hematoxylin-eosin(HE)staining was performed to analyze the pathological changes of the rat esophagus,and Western Blotting was used to detect the expression of nuclear factor-κB(NF-κB)inflammatory protein.Results:Compared with the control group,the total food intake and body weight of the rats within 7 d after modeling were significantly decreased(P<0.05),and the expressions of pain-related factors PGE-2,SP,and CGRP were higher than those of the control group(P<0.05).,the esophageal pathological damage score increased(P<0.05),and the expression of NF-κB inflammatory protein increased(P<0.05);after treatment,the total food intake of the rats in the nano-Kuiyangye intervention group within 7 days after modeling was higher than that in other groups(P<0.05),the expressions of pain-related factors PGE-2,SP,and CGRP were lower than those in the model group(P<0.05),the esophageal pathological damage score was lower(P<0.05),and the expression of NF-κB inflammatory proteins was lower(P<0.05).Conclusion:Nano-Kuiyangye increases the food intake of rats with radiation esophagitis,reduces esophageal tissue damage,and reduces the concentration of serum pain factors;the anti-inflammatory effect of nano-Kuiyangye may be related to the reduction of NF-κB inflammatory factor levels.
基金Project supported by the National Natural Science Foundation of China(No.30570323)Foundation of State Developing and Reforming Committee(No.IFZ20051210)
文摘The hydroponic culture experiments of soybean bean seedlings were conducted to investigate the effect of lanthanum (La) on nitrogen metabolism under two different levels of elevated UV-B radiation (UV-B, 280-320 nm). The whole process of nitrogen metabolism involves uptake and transport of nitrate, nitrate assimilation, ammonium assimilation, amino acid biosynthesis, and protein synthesis. Compared with the control, UV-B radiation with the intensity of low level 0.15 W/m^2 and high level 0.45 W/m^2 significantly affected the whole nitrogen metabolism in soybean seedlings (p 〈 0.05). It restricted uptake and transport of NO3^-, inhibited activity of some key nitrogen-metabolism-related enzymes, such as: nitrate reductase (NR) to the nitrate reduction, glutamine systhetase (GS) and glutamine synthase (GOGAT) to the ammonia assimilation, while it increased the content of free amino acids and decreased that of soluble protein as well. The damage effect of high level of UV-B radiation on nitrogen metabolism was greater than that of low level. And UV-B radiation promoted the activity of the anti-adversity enzyme glutamate dehydrogenase (GDH), which reduced the toxicity of excess ammonia in plant. After pretreatment with the optimum concentration of La (20 mg/L), La could increase the activity of NR, GS, GOGAT, and GDH, and ammonia assimilation, but decrease nitrate and ammonia accumulation. In conclusion, La could relieve the damage effect of UV-B radiation on plant by regulating nitrogen metabolism process, and its alleviating effect under low level was better than that under the high one.
基金supported by the National Natural Science Foundation of China under contract No.30270258Scientific Research Rewards Founda-tion for Outstanding Youth Scientists of Shandong Province under contract No.03BS120.
文摘The responses of the interspecific competition between Skeletonema costatum and Heterosigma akashiwo to UV-B radiation enhancement were studied by the co-culture method. The results showed that Heterosigma akashiwo exhibited inhibition on the growth of Skeletonema costatum, and with the increase of initial inoculation density of Heterosigma akashiwo, heavier inhibition on Skeletonema costatum appeared. Under different inoculation proportions, Heterosigma akashiwo could always be in predominance in competition with Skeletonema costatum. The UV-B radiation treatment could change the competition relationship between Skeletonema costatum and Heterosigma akashiwo, which could increase the competitive dominance of Skeletonema costatum and decrease the competitive dominance of Heterosigma akashiwo. When the inoculation proportions of Heterosigma akashiwo and Skeletonema costatum were H∶S=1∶4 and H∶S=1∶1,Skeletonema costatum was in predominance in this competition; however, Heterosigma akashiwo was in predominance when the inoculation proportion was H∶S=4∶1.
文摘Enhanced UV-B(280-320 nm) radiation resulting from ozone depletion is one of global environmental problems. Not only marine organisms but also marine ecosystems can be affected by enhanced UV-B radiation. The effects of UV-B radiation on interaction of macro-algae and micro-algae were investigated using Ulva pertusa Kjellman and Alexandrium tamarense as the materials in this study. The results demonstrated that UV-B radiation could inhibit the growth of Ulva pertusa and Alexandrium tamarense when they were both mono-cultured, and the growth inhibition of algae was more significant with increasing doses of UV-B radiation. Alexandrium tamarense could inhibit the growth of Ulva pertusa in mixed culture, and the growth inhibition was more significant when increasing the initial cell density. However, Ulva pertusa could inhibit the growth of Alexandrium tamarense in early phase and stimulate the growth in latter phase when they were grown in mixed culture. Lower initial cell density(10~2 cell/ml) of Alexandrium tamarense could inhibit the growth of Ulva pertusa under UV-B radiation treatment,however, with the initial cell density increasing(10~3 and 10~4 cell/ml), the growth of Ulva pertusa was stimulated under lower dose of UV-B radiation and inhibited under higher dose of UV-B radiation by Alexandrium tamarense. Compared with that in mixed culture, Ulva pertusa showed more positive inhibition to the growth of Alexandrium tamarense under UV-B radiation treatment.
基金Supported by the Program for New Century Excellent Talents in University(No.NCET-05-0597)the National Natural Science Foundation of China(No.30270258)
文摘We evaluated the effects of red and blue light on the repair of UV-B radiation-induced damage in tetraspores of Chondrus ocellatus Holm. Tetraspores of C. ocellatus were treated with different UV-B radiation levels(0,36,72,108,144 and 180 J/m2),and thereafter subjected to PAR,darkness,or red or blue light during a 2-h repair stage,each day for 48 days. The diameters and cellular contents of cyclobutane pyrimidine dimmers(CPDs),chlorophyll a(Chl a),phycoerythrin,and UV-B-absorbing mycosporinelike amino acids(MAAs) contents of the tetraspores were determined. Our results show that low doses of UV-B radiation(36 and 72 J/m 2) promoted the growth of C. ocellatus; however,increased UV-B radiation gradually reduced the C. ocellatus growth(greater than 72 J/m2). The MAAs(palythine and asterina-330) in C. ocellatus were detected and analyzed by LC/MS. Our results suggest that moderate red light could induce the growth of this alga in aquaculture. In addition,photorepair was inhibited by red light,so there may be some other DNA repair mechanism activated by red light. Blue light promoted the activity of DNA photolyase,greatly improving remediation efficiency. Red and blue lights were found to reduce the capacity of C. ocellatus to form MAAs. Therefore,PAR,red light,and blue light play different roles during the repair processes for damage induced by UV-B radiation.
基金Supported by the National Natural Science Foundation of China (30270258, 40506028)the National High Technology Research and Development Program of China (2002AA648010)+1 种基金the Encouraging Foundation for Outstanding Youth Scientists of Shandong Province (03BS120)China Postdoctoral Sience Foundation(2005037237)
文摘Effect of UV-B radiation on ingesting and nutritional selecting behavior of the roifer Brachionus urceus on 5 species of microlgae were studied under controlled laboratory conditions. Restdts showed that enhanced UV-B radiation significantly inhibited ingesting of the rotifer B. urceus when it was fed with 5 species of micro-algae (p〈0.05). The ingesting selectivity rate varied with the UV-B radiation enhancement when it was fed with 5 species micro-algal mixture. Results indicated that the enhanced UV-B radiation could affect ingesting and nutritional selectivity of B. urceus.