UV-B Intensity Research Articles

Modulation of COVID19 Epidemiology by UV-B and - A Photons from the Sun

It is well known that 200-290 nm ultraviolet photons (hereinafter UV-C radiation) photo-chemically interacts with DNA and RNA and are endowed with germicidal properties that are also effective on viruses (1-8). Fortunately, Solar UV-C photons of this wavelength are filtered out by the Ozone layer of the upper Atmosphere, at around 35 km (9). Softer UV photons from the Sun with wavelengths in the range 290-320 nm (UV-B) and 320-400 nm (UV-A), however, do reach the Earth’s surface. The effect of these photons on Single- and Double-Stranded RNA/DNA viruses (9-12) and the possible role they play on the seasonality of epidemics (13), are nevertheless little studied and highly debated in alternative or complementarity to other environmental causes (14-20). Notably though, the effects of both direct and indirect radiation from the Sun needs to be considered in order to completely explain the effects of UV radiations in life processes (with e.g. the UV virucidal effect enhanced in combination to the concomitant process of water droplets depletion because of Solar heat). Herein we present a number of concurring circumstantial evidence suggesting that the evolution and strength of the recent Severe Acute Respiratory Syndrome (SARS-CoV-2) pandemics (21, 22), might be have been modulated by the intensity of UV-B and UV-A Solar radiation hitting different regions of Earth during the diffusion of the outbreak between January and May 2020. Out findings, if confirmed by more in depth data analysis and modeling of the epidemics, which includes Solar modulation, could help in designing the social behaviors to be adopted depending on season and environmental conditions.

Water chemistry and light effects on survival of hatching salmonids in spring channels

This study informs the restoration and development of salmonid fisheries and aquaculture facilities regarding water quality and light effects on hatching survival in spring channels. Brook trout Salvelinus fontinalis eggs were hatched in springs from karst and silica-clastic aquifers to determine whether survival was affected by water quality in differing geological areas. Nitrogen gas saturation (N2) was highest in karst springs and impacted survival, with a negative relationship between N2 and survival during hatching (> 110% N2 corresponded to 70.5% survival). A multiple regression model was developed to predict survival that included N2, acid neutralizing capacity (ANC), and light intensity (Light) following the equation: In a follow-up experiment, brook trout eggs were fertilized and hatched in hatching boxes in high and low levels of ultraviolet light (UV), fluorescent light, and complete darkness to test the effects of UV and light intensity on survival. Logistic regression was used to model the probability of mortality as a function of UV-B intensity. Results indicated freshly fertilized eggs were more severely impacted by light and UV than post-eyed eggs, and both UV and fluorescent light treatments experienced high mortality compared to the treatment in complete darkness. Karst springs with intermediate concentrations of calcium and increased ANC provide improved water quality for salmonids as compared to silica-clastic aquifers; however, high N2 can have negative effects on survival which, could be overcome by aeration within spring channels. Furthermore, using advanced aquaculture techniques, it may be possible to develop a brood stock that is resistant to the effects of N2. Effects of UV and light intensity pose additional challenges at early life stages for salmonids which, can be overcome by shading hatch boxes in the spring channel.

Acclimation to low ultraviolet-B radiation increases photosystem I abundance and cyclic electron transfer with enhanced photosynthesis and growth in the cyanobacterium Nostoc sphaeroides.

Ultraviolet-B radiation is known to harm most photosynthetic organisms with the exception of several studies of photosynthetic eukaryotes in which UV-B showed positive effects. In this study, we investigated the effect of acclimation to low UV-B radiation on growth and photosynthesis of the cyanobacterium Nostoc sphaeroides. Exposure to 0.08 W m-2 UV-B plus low visible light for 14 d significantly increased the growth rate and biomass production by 16% and 30%, respectively, compared with those under visible light alone. The UV-B acclimated cells showed an approximately 50% increase in photosynthetic efficiency (α) and photosynthetic capacity (Pmax ), a higher PSI/PSII fluorescence ratio, an increase in PSI content and consequently enhanced cyclic electron flow, relative to those of non-acclimated cells. Both the primary quinone-type acceptor and plastoquinone pool re-oxidation were up-regulated in the UV-B acclimated cells. In parallel, the UV-B acclimated colonies maintained a higher rate of D1 protein synthesis following exposure to elevated intensity of UV-B or visible light, thus functionally mitigating photoinhibition. The present data provide novel insight into photosynthetic acclimation to low UV-B radiation and suggest that UV-B may act as a positive ecological factor for the productivity of some photosynthetic prokaryotes, especially during twilight periods or in shaded environments.

UV-B Induces Chloroplast Movements in a Phototropin-Dependent Manner.

We examined the impact of UV-B irradiation on chloroplast movements in Arabidopsis leaves. Directional chloroplast movements induced by blue light have been described in multiple plant species. In weak light, chloroplasts accumulate at periclinal cell walls to increase light capture. In strong light, chloroplasts exhibit the avoidance response, as they move towards anticlinal walls to protect the photosynthetic apparatus from light-induced damage. In Arabidopsis, chloroplast movements are triggered by phototropins, phot1 and phot2, which are known as blue/UV-A photoreceptors. We found that irradiation with UV-B of 3.3 µmol·m−2·s−1 induced chloroplast accumulation in wild-type plants. UV-B-triggered accumulation was dependent on the presence of phototropins, especially phot1, but not on UVR8 (the canonical UV-B photoreceptor). Irradiation with strong UV-B of 20 µmol·m−2·s−1 did not induce substantial chloroplast relocations in wild-type leaves. However, in the jac1 mutant, which is defective in chloroplast accumulation, strong UV-B elicited chloroplast avoidance. This indicated that UV-B can also activate signaling to the avoidance response. To assess the possibility of indirect effects of UV-B on chloroplast movements, we examined the impact of UV-B on the actin cytoskeleton, which serves as the motile system for chloroplast movements. While irradiation with UV-B of 3.3 µmol·m−2·s−1 did not affect the actin cytoskeleton, strong UV-B disrupted its structure as shown using an Arabidopsis line expressing Lifeact-green fluorescent protein (GFP). In wild-type plants, pretreatment with strong UV-B attenuated chloroplast responses triggered by subsequent blue light irradiation, further indicating that this UV-B intensity also indirectly affects chloroplast movements. Taken together, our results suggest that the effect of UV-B on chloroplast movement is twofold: it directly induces phototropin-mediated movements; however, at higher intensities, it attenuates the movements in a nonspecific manner.

Exotic plant species are locally adapted but not to high ultraviolet-B radiation: a reciprocal multispecies experiment.

Ultraviolet (UV) radiation intensities differ among global regions, with significantly higher levels in the southern hemisphere. UV-B may act as an environmental filter during plant invasions, which might particularly apply to plant species from Europe introduced to New Zealand. Just like for any other abiotic or biotic filter, successful invaders can cope with novel environmental conditions via plastic responses and/or through rapid adaptation by natural selection in the exotic range. We conducted a multispecies experiment with herbaceous plants in two common gardens located in the species' native and exotic ranges, in Germany and New Zealand, respectively. We used plants of German and New Zealand origin of eight species to test for adaptation to higher UV-B radiation in their new range. In each common garden, all plants were exposed to three radiation treatments: (1) ambient sunlight, (2) exclusion of UV-B while transmitting ambient UV-A, and (3) combined exclusion of UV-B and UV-A. Linear mixed-effect models revealed significant effects of UV-B on growth and leaf traits and an indication for UV-B-induced biomass reduction in both common gardens pointing to an impact of natural, ambient UV radiation intensities experienced by plants in the northern and in the southern hemisphere. In both common gardens, the respective local plants (i.e., German origins in Germany, New Zealand origins in New Zealand) displayed enhanced productivity and aboveground biomass allocation, thus providing evidence for recent evolutionary processes in the exotic range. Genetic differentiation between different origins in consequence of divergent local selection pressures was found for specific leaf area. This differentiation particularly hints at different selective forces in both ranges while only little evidence was found for an immediate selective effect of high UV-B intensities in the exotic range. However, reaction norm slopes across ranges revealed higher plasticity of exotic individuals in functional leaf traits that might allow for a more sensitive regulation of photoprotection measures in response to UV-B. During the colonization, New Zealand populations might have been selected for the observed higher phenotypic plasticity and a consequently increased ability to successfully spread in the exotic range.

Photoexcited triclosan induced DNA damage and oxidative stress via p38 MAP kinase signaling involving type I radicals under sunlight/UVB exposure

Triclosan (TCS) is an antimicrobial preservative used in personal care products. Here, we have studied the phototoxicity, photogenotoxicity of TCS and its molecular mechanism involving p38 mitogen activated protein kinase (MAPK) pathway under UVB/sunlight exposure. We found that TCS showed photodegradation and photoproducts formation under UVB/sunlight. In silico study suggests that photosensitized TCS loses its preservative property due to the formation of its photoproducts. Photosensitized TCS induces significant O2•−, •OH generation and lipid peroxidation via type-I photochemical reaction mechanism under UVB/sunlight exposure. We performed intracellular study of TCS on human skin keratinocytes (HaCaT cell-line) under the ambient intensity of UVB (0.6 mW/cm2) and sunlight exposure. Significant intracellular ROS generation was observed through DCFH2-DA/DHE assays along with a significant reduction in cell viability through MTT and NRU assays in photosensitized TCS. Photosensitized TCS also induces endoplasmic reticulum (ER) stress as shown through ER-tracker/DAPI staining and Ca2+ release. It further induced cell cycle arrest through the sub-G1 phase augmentation and caused lysosomal/mitochondrial destabilization. Photogenotoxicity was shown through significant tail DNA, micronuclei and cyclobutane pyrimidine dimers (CPDs) formations. Cell signaling mechanism implicated upregulated expression of cleaved Caspase-3, Bax, phospho-p38, phospho-JNK and cytochrome C, thereby downregulated Bcl-2 expressions. Results advocate that TCS induces phototoxic effects via type I mediated photodynamic mechanism and activation of MAPK pathway. We conclude that photoexcited TCS may be deleterious to human health at the ambient environmental intensities of sunlight reaching at the earth's surface. Therefore, it may be replaced by alternative safe preservative.

Arabidopsis E2Fc is required for the DNA damage response under UV‐B radiation epistatically over the microRNA396 and independently of E2Fe

UV-B radiation inhibits plant growth, and this inhibition is, to a certain extent, regulated by miR396-mediated repression of Growth Regulating Transcription factors (GRFs). Moreover, E2Fe transcription factor also modulates Arabidopsis leaf growth. Here, we provide evidence that, at UV-B intensities that induce DNA damage, E2Fc participates in the inhibition of cell proliferation. We demonstrate that E2Fc-deficient plants show a lower inhibition of leaf size under UV-B conditions that damage DNA, decreased cell death after exposure and altered SOG1 and ATR expression. Interestingly, the previously reported participation of E2Fe in UV-B responses, which is a transcriptional target of E2Fc, is independent and different from that described for E2Fc. Conversely, we here demonstrate that E2Fc has an epistatic role over the miR396 pathway under UV-B conditions. Finally, we show that inhibition of cell proliferation by UV-B is independent of the regulation of class II TCP transcription factors. Together, our results demonstrate that E2Fc is required for miR396 activity on cell proliferation under UV-B, and that its role is independent of E2Fe, probably modulating DNA damage responses through the regulation of SOG1 and ATR transcript levels.

UV-B irradiation effects on pigments and cytological behaviour of callus in sainfoin (Onobrychis viciifolia Scop.)

PurposeThis study aims to determine the appropriate irradiation dose for induction of somaclonal variation in mass of unorganized parenchyma cells derived from sainfoin (Onobrychis viciifolia) tissues.Design/methodology/approachTo investigate the feasibility of UV-B irradiation (312 nm), seeds and callus of sainfoin were exposed to five different intensities (20-100 per cent) for evaluating the effectiveness of phytochemical constituents and cellular behaviour.FindingsAlthough percentage of seed viability reduced in 20 per cent intensity of UV-B irradiation compared with control seeds, the germination speed significantly enhanced from 3.58 to 5.42. The spectrophotometer analysis confirmed that concentrations of chlorophyll (a and b) decreased after UV-B exposure as compared with control callus. Also, carotenoid content showed significant differences among treated calli. Flavonoid and phenolic contents were observed to gradually increase when the non-irradiated callus subjected to 40 and 60 per cent intensities of UV-B irradiation, respectively. Observation on cellular behaviour such as determination of nuclear and cell areas, mitotic index and chromosomal aberrations were also detected to change in different intensities of UV-B irradiation. Fragmented and aneuploidy aberrations were only observed in exposed cells with more than 40 per cent intensity of UV-B irradiation.Originality/valueIn reality, radiocytological evaluation was proven to be essential in deducing the effectiveness of UV-B irradiation to induce somaclonal variation in callus tissue of sainfoin.

Effects of Temperature and Photorepair Radiation on a Marine Ciliate Exposed to UVB Radiation.

The influences of intensity and repeated exposure to ultraviolet-B radiation (UVB), photoreactivating repair radiation (PRR), and temperature on the scuticociliate Parauronema acutumwere explored under laboratory conditions. Population growth was negatively affected after exposure to the equivalent of one sunny summer day of ambient UVB, especially in the absence of PRR. Repeated dailyexposure to UVB severely compromised ciliate survival. UVB-exposed treatments without PRR recovered slower and reached lower final abundances than treatments receiving PRR. Reducing the daily UVB exposure approximately 25% improved ciliate recovery after exposure. In the single exposure treatments, temperature effects were not consistent, except that growth was slowest for control and treatments at the lowest temperature (15°C). These data suggest that dark repair and/or photoprotection are present in P.acutum, but photoenzymatic repair was the more effective mechanism in reversing UVB damage. Repeated exposure treatments without PRR had zero or declining growth at all temperatures (15, 20 and 25°C), as did those with PRR at 15°C. Significant temperature/dose differences were identified in the repeated exposure treatments; ciliates subjected to the higher UVB intensity with PRR survived only at 25°C, while ciliate populations under reduced UVB increased at 20 and 25°C.

紫外长期胁迫对高世代麦长管蚜生命表参数的影响

PDF HTML阅读 XML下载 导出引用 引用提醒 紫外长期胁迫对高世代麦长管蚜生命表参数的影响 DOI: 10.5846/stxb201709221699 作者: 作者单位: 昆虫生态实验室,昆虫生态实验室,昆虫生态实验室,昆虫生态实验室,昆虫生态实验室 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目（39970112，20470268）；高校博士点基金（20130204110004）；陕西省科技厅国际合作项目（2012） Effects of ultraviolet continuous processing on life table parameters of high generations of Sitobion avenae (Fabricius) Author: Affiliation: Insect ecology laboratory,Insect ecology laboratory,Insect ecology laboratory,Insect ecology laboratory,Insect ecology laboratory Fund Project: National Natural Science Foundation of China ( NSFC ) 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:为了评估紫外连续处理对第20代以后麦长管蚜Sitobion avenae（Fabricius）种群动态的影响，采用特定年龄生命表方法，设置不同强度（0，0.50，0.70 mW/cm2）UV-B连续多代处理麦长管蚜成虫，统计经紫外处理后的麦长管蚜第22代，第27代，第32代，第37代麦长管蚜生命表种群参数的变化并总结了1-37代麦长管蚜内禀增长率的变化规律。结果表明：（1）处理组供试麦长管蚜平均世代周期（T）呈先显著升高后下降的趋势。（2）低强度处理组内禀增长率（rm）、净增殖率（R0）、周限增长率（λ）均呈先升高后下降又升高的趋势，高强度处理组供试麦长管蚜内禀增长率（rm）、净增殖率（R0）、周限增长率（λ）呈先下降后显著升高的的趋势，且均在G37达到最大值。（3）1-37代处理组麦长管蚜rm呈现先显著增高后下降又升高又下降又显著升高的变化规律，且均在G37达到最大值。由此可见：麦长管蚜经过多代的UV-B胁迫后，对其生命表参数的影响依然显著，在G37麦长管蚜对紫外的适应能力最强。本研究的创新点在于解析了第22代以后紫外胁迫对麦长管蚜种群动态的影响，从而为全面深入的阐述紫外胁迫对麦长管蚜生长繁殖的影响规律，掌握不同紫外胁迫下的剂量效应关系及麦长管蚜的适应性提供实验基础和理论依据。 Abstract:With the appearance of the hole in the ozone and depletion of the stratosphere and the ozone, there is increasing concern about the changing trend in UV-B radiation levels and the impact of increased UV-B on organisms and ecosystems. As the environment is continuously being destroyed, irradiation intensity of UV-B has been enhanced. The aphid, Sitobion avenae (Fabricius), belonging to the suborder Homoptera, and the family Aphididae, is distributed in wheat-producing regions in China. Aphids are parasites of wheat, barley and oats, rice, corn, sugar cane, and grasses in southern China. In the early stages, aphids accumulate on the front or back of leaves, and in the later stages, they accumulate in ear to suck out the fluid, causing the injured plant to experience reduced growth, tiller reduction, 1000-grain weight. Aphids are an important pest in grain crops, which are also the dominant plants attacked by aphids that have a short growth cycle, breed quickly, and are highly adaptable. Studies on the effects of UV-B on insects are rare. Thus, additional studies are required to predict the effect of increased UV-B irradiation on the genetic evolution of S. avenae). In order to investigate the effects of ultraviolet continuous processing on the population dynamics of S. avenae after the 20th generation, we adopted certain age life tables to calculate the S. avenae life table parameters and used different strength UV-B (0, 0.50, and 0.70 mW/cm2) to treat S. avenae after the 20th generation. This analysis was intended to provide a theoretical foundation for understanding the long-term development, growth, and reproduction of S. avenae. Changes in the population parameters of the 22nd generation, the 27th generation, the 32nd generation, the 37th generation, and the intrinsic rate of increase from the first generation to the 37th generation of the aphid were studied. The results showed that:(1) The average generation cycle (T) of treatments significantly increased and then decreased; (2) in the low-intensity treatment group, intrinsic rate of increase, net appreciation rate, and weekly growth rate increased first and then decreased, before increasing again; in the high-intensity treatment group, net appreciation rate, weekly growth rate, and fecundity decreased first and then significantly increased, and they all reached the maximum in the 37th generation; and finally, (3) in the treatment group, the intrinsic rate of increase of the aphids significantly increased and then decreased twice and then significantly increased. Our study showed that after several generations of UV-B stress, the effect on the life table parameters was significant and the ability of aphids to adapt to UV radiation was strongest in the 37th generation. The aim of this study was to reveal and analyze the effects of UV stress on population dynamics of Sitobion avenae after the 22nd generation. Consequently, our data provide a long-term and in-depth understanding of the developmental effects of UV stress on the growth and reproduction of Sitobion avenae. In addition, the findings provide experimental and theoretical bases for elucidating the dose-effect relationship under different ultraviolet stress levels and the adaptability of a long-tube aphid to increased UV-B levels. 参考文献 相似文献 引证文献

203 - Phototoxic Mechanism of Triclosan through Involvement of Type 1 mediated apoptosis in HaCaT cell line

Triclosan (TCS) is a widely used preservative in personal care products such as toothpaste, soaps and cosmetics. However its molecular mechanism under ambient ultraviolet radiation and sunlight is not well understood. In this study, we investigated phototoxic effects of TCS in HaCaT cell line under ambient intensity of UVB and sunlight exposure. TCS generates reactive oxygen species (ROS), superoxide anion (O2•‒) and hydroxyl radical (•OH) formation through type-I photodynamic mechanism. Photodegradation study has been done under UVB and sunlight exposures. Thereafter, cell viability parameters were measured using MTT, NRU assays and LDH leakage. TCS decreased cell viability of treated cells in a concentration-dependent manner along with increased expressions of apoptotic markers such as phosphatidylserine translocation, Acridine orange/Ethidium bromide double staining. Significant intracellular ROS generation was measured through DCF-DA and DHE staining. Further cell cycle study showed sub G1 population and lysosomal destabilization, through acridine orange and neutral red staining which advocates apoptotic cell death. Here we found TCS (5 µg/mL) showed reduction of mitochondrial membrane potential through JC-1, mitotracker/ Dapi staining and transmission electron microscopy. Photogenotoxicity assay was performed using comet assay and micronuclei formation. To explore the mechanisms we measured the activation of cleaved Caspase-3, Bax, while reduced expression of Bcl-2 through real time and western blotting which further leads to apoptosis. Thus study suggests that TCS leads to apoptosis via the involvement of lysosome and mitochondria both under ambient UVB and sunlight exposure. In conclusion, TCS exposure may be deleterious to human health at ambient environmental intensities. Therefore, TCS should be replaced by other photosafe preservatives for human beings.

Photosensitized methyl paraben induces apoptosis via caspase dependent pathway under ambient UVB exposure in human skin cells

Methyl paraben (MP), is a widely used preservative in pharmaceutical, food and cosmetic products. Its molecular mechanism under ambient ultraviolet radiation is not well understood. We investigated photosensitizing mechanism of MP under ambient UVB (0.6 mW/cm2) intensity. MP showed dose dependent decrease in cell viability of human keratinocyte cell line (HaCaT) by MTT and NRU assays. Study showed 40% reduction in antimicrobial activity of UVB irradiated MP through E. coli culture. Photosensitized MP (25 μg/ml) significantly enhanced lipid peroxidation, intracellular ROS generation and disrupted mitochondrial membrane integrity. MP induced loss of lysosomal membrane integrity and endoplasmic reticulum (ER) mediated stress evident from Ca+2 release. Phototoxicity of MP showed nuclear fragmentation, phosphatidylserine translocation, 30% tail DNA and micronuclei formation. Study showed mitochondria mediated apoptosis via upregulation of Bax, Apaf-1, Cytochrome C and Caspase-3. Upregulation of Caspase-12 (2 folds) specifically showed role of ER in apoptosis. Specific caspase inhibitor, Z-VAD-FMK showed involvement of caspase cascade pathway in apoptosis. Results indicate that photosensitive MP leads to oxidative stress mediated DNA damage and apoptosis through mitochondria and ER. MP causes deleterious effects and its long term exposure to human skin may promote skin diseases. Therefore, MP should be replaced by other photosafe preservatives for humans.

Role of UV-B irradiation dose and intensity on color retention and antioxidant elicitation in broccoli florets (Brassica oleracea var. Italica)

Postharvest UV exposure has been useful to i) delay senescence and ii) induce the accumulation of bioactive compounds in some vegetable species. However, no studies have been conducted to determine the treatment conditions (radiation dose and intensity) required to maximize these two diverse responses. In this work, we evaluated the effect of UV-B irradiation intensity (Control: 0, Low: 3.2, Medium: 4.0 and High: 5.0W/m2) and dose (0, 2, 4, 8, 12kJ/m2) on quality retention and antioxidant capacity of fresh broccoli florets during storage (4°C for 17days). Exposure to Low UV-B radiation and dose (2, 4kJ/m2) reduced broccoli weight loss, delayed yellowing and improved chlorophyll and chlorophyllide retention. After long term storage, no marked improvement on the antioxidant capacity was found regardless of the irradiation condition. Evaluations at short time after UV-B exposure (0, 2, 6, 18h) indicated that the treatments elicited antioxidant accumulation. Greatest antioxidant capacity was found in broccoli subjected to High intensity UV-B. Increased levels of aliphatic glucosinolates were found 18h after the UV-B irradiation, whereas phenolic antioxidants peaked 6h after the treatment. Results showed that Low UV-B doses and intensities delayed chlorophyll degradation and may be useful to complement refrigeration in fresh broccoli. Instead, High intensity UV-B exposure may be better suited as a pre-treatment to increase the antioxidant capacity prior to further processing such us freezing.

UV-B长期胁迫对麦长管蚜子代种群动态的影响

PDF HTML阅读 XML下载 导出引用 引用提醒 UV-B长期胁迫对麦长管蚜子代种群动态的影响 DOI: 10.5846/stxb201611172338 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目（39970112，20470268）；高校博士点基金（20130204110004）；陕西省科技厅国际合作项目（2012） Effect on population dynamics of the offspring of Sitobion avenae Fabricius (Hemiptera: Aphididae) exposed to long term UV-B stress Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:为了探明UV-B长期辐射亲代麦长管蚜Sitobion avenae Fabricius后对其子代种群动态的影响。采用特定年龄生命表方法，设置不同强度（0，0.50，0.70 mW/cm2）UV-B连续多代处理麦长管蚜成虫，统计麦长管蚜分别经历UV-B辐射一代，六代，十一代，十五代后其子代麦长管蚜存活率和繁殖力、繁殖参数、种群参数的变化。结果表明：（1）经UV-B处理亲代麦长管蚜后，其子代种群的内禀增长率r与周限增长率λ在低强度处理组各世代之间无显著差异，在高强度处理组各世代之间呈先上升后下降的趋势。（2）处理组麦长管蚜种群繁殖力F、净增殖率R0、平均世代周期T、产卵天数和成蚜寿命均在G7代达到最大值，且与对照组无显著差异。（3）亲代麦长管蚜经UV-B胁迫处理后对子代种群的存活率影响显著。研究结论：亲代麦长管蚜经过不同代数的UV-B胁迫，可显著影响子代的生长发育与繁殖，且对处于不同世代的子代生态学指标产生不同影响。研究的创新点在于探究亲代麦长管蚜经历紫外胁迫后对其子代生长、发育与繁殖的影响，为逆境胁迫下蚜虫的生态遗传与进化机理提供理论依据。 Abstract:Recently, ultraviolet-B radiation (UV-B) has been proven to have a strong selection pressure on the biosphere and ecological environment, significantly influencing living organisms. The rapid increase of solar UV-B reaching the surface of the earth is owing to stratospheric ozone depletion caused primarily by the Industrial Revolution. The responses of insect physioecology and growth to ultraviolet radiation enhancement have received increasing attention in the scientific community. Sitobion avenae Fabricius (Hemiptera:Aphididae) is a common wheat pest. It affects plants by ingesting sap from the ears, stems, leaves, and other tender plant parts. It also transmits viruses (e.g., barley yellow dwarf virus) during feeding, thereby reducing wheat yield and quality. It is a good subject for research because of its special characteristics of parthenogenesis and high fecundity. The increase of UV-B levels may fundamentally affect the population dynamics of S. avenae by altering its normal growth, development, and fecundity. The two-sex life table analysis is a common method to indicate biological growth, development, and fecundity, and includes the entire population (males, females, and those that die before the adult stages), so that the result is more realistic than analyses based only on the means of development time. To explore the effect on population dynamics of the offspring of S. avenae by exposing the mother generation to UV-B for a long time, the age-specific life table of S. avenae was established to evaluate life-table parameters of offspring of S. avenae. The mother generation was radiated to different intensities of UV-B (0, 0.5, 0.7 mW/cm2) for one, six, eleven, and fifteen generations. The results showed that:(1) There were no significant differences in the intrinsic rate of increase (r) and finite rate of increase (λ) among the treatment group of each generation under low intensity of UV-B, whereas the parameters of r and λ first increased and then fell with generations under high intensity of UV-B. (2) The effect of UV-B on the fecundity (F), net reproductive rate (R0), mean generation time (T), oviposition duration, and adult longevity peaked in the seventh generation. Moreover, no significant difference was found in the seventh generation between the control and treatment groups. (3) When S. avenae were under different intensity of UV-B radiation in the same generation, most parameters in the treatments groups were significantly lower than those in the control except the parameter T in the second and sixteenth generation. However, no significant difference was found in the seventh generation between the control groups and treatment groups, whereas F, R0, T, oviposition days, and adult longevity all had significant differences, but there were no significant differences between other parameters in the twelfth generation. (4) The survival rate of offspring of S. avenae exposed to UV-B stress was significantly influenced. Our research showed that the effect of long-term UV-B stress on S. avenae was accumulated in the progeny, had different impacts in different generations. Our research showed the population dynamics of the offspring of S. avenae after the mother generation was influenced by UV-B; thus, the results may provide a theoretical basis for ecological genetics and evolutionary mechanisms of aphid under adversity stress. 参考文献 相似文献 引证文献

Environmental determinants of previtamin D synthesis in the United Arab Emirates.

ABSTRACTDespite abundant sunshine throughout the year, vitamin D deficiency is endemic in the UAE. Solar radiation within the UVB range of the spectrum is required for the photosynthesis of previtamin D3 in the skin. Atmospheric transmission of UVB is strongly influenced by atmospheric conditions and solar zenith angle. We investigated the effects of diurnal and seasonal variation on the availability of sufficient UVB radiation for adequate previtamin D3 synthesis using an established in vitro model. Borosilicate ampoules of 7-dehydrocholesterol, the precursor of previtamin D3, in ethanol (50 µg/mL) were exposed to direct sunlight in an urban area of Abu Dhabi, at one hourly intervals between 0800 and 1700, on one day of each month over a period of one year. Conversion to previtamin D3, vitamin D3 and metabolically inactive photoisomers was analyzed using high performance liquid chromatography. The efficiency of 7-dehydrocholesterol conversion to previtamin D3 varied estimated UVB intensity. At the latitude of Abu Dhabi (24.2 N) previtamin D3 synthesis can occur throughout the year. However very little if any previtamin D3 was produced before 0900 hrs.and after 1600 hrs. Local conditions in Abu Dhabi are likely sufficient to maintain vitamin D levels throughout the year given adequate sun exposure.

A Novel Gd3+–Pb2+ Doped LiSrPO4 Phosphor for Phototherapy Lamp Applications

The phosphors LiSrPO4:Gd3+ and LiSrPO4:Gd3+, Pb2+ with different concentration of Gd3+ and Pb2+ were synthesized by combination of re-crystallization and modified solid state diffusion method. The synthesized phosphors were characterized using XRD, SEM and PL spectroscopies. The PL excitation spectra of LiSrPO4:Gd3+ phosphor exhibit peak at 275 nm due to the 8S7/2 →4IJ transition of Gd3+ ions and gave narrow UVB emission at 312 nm. The effect of Pb2+ ions on the PL properties of LiSrPO4:Gd3+have also been investigated. Upon the addition of Pb2+ ions, the excitation of phosphors shows broad peak with maximum at 247 nm, overlapping the Hg 253.7 nm line. This addition of Pb2+ ions improved the emission intensity of narrow band UVB i.e. 312 nm under the excitation of 247 nm. The phosphor could be good candidate as phototherapy lamp phosphor material.

Surviving but not thriving: inconsistent responses of zooxanthellate jellyfish polyps to ocean warming and future UV-B scenarios.

Complex changes to UV radiation at the Earth’s surface are occurring concurrently with ocean warming. Despite few empirical tests, jellyfish are hypothesised to be increasing in some parts of the world because they are robust to environmental stressors. Here we examine the effects of UV-B and ocean warming projections on zooxanthellate jellyfish polyps. We exposed Cassiopea sp. polyps to three levels of UV-B (future-low (1.43 Wm2), current (1.60 Wm2), future-high (1.77 Wm2)) and two levels of temperature (current-day (25 °C) and future (28 °C)) over 6 weeks. The intensity of UV-B was varied throughout the day to mimic diel variation in UV-B irradiance. Polyp survival, asexual reproduction and YII were measured. In the current and future-high UV-B treatments, more polyps were produced in 25 °C than 28 °C. This pattern, however, was reversed under future-low UV-B conditions, where more polyps were produced at 28 °C. YII was highest under current summer conditions and future conditions of low UV-B and increased temperature. YII, however, was reduced under high UV-B conditions but was further reduced with warming. Our results suggest that although Cassiopea polyps may survive elevated UV-B and warming conditions, they are unlikely to thrive. If, however, UV-B radiation decreases then ocean warming may facilitate increases in Cassiopea populations.

UV-B Exposure Affects the Biosynthesis of Microcystin in Toxic Microcystis aeruginosa Cells and Its Degradation in the Extracellular Space.

Microcystins (MCs) are cyclic hepatotoxic heptapeptides produced by cyanobacteria that can be toxic to aquatic and terrestrial organisms. MC synthesis and degradation are thought to be influenced by several different physical and environmental parameters. In this study, the effects of different intensities of UV-B radiation on MC biosynthesis in Microcystis cells and on its extracellular degradation were investigated by mRNA analysis and degradation experiments. Exposure to UV-B at intensities of 1.02 and 1.45 W/m2 not only remarkably inhibited the growth of Microcystis, but also led to a decrease in the MC concentration. In addition, mcyD transcription was decreased under the same UV-B intensities. These results demonstrated that the effects of UV-B exposure on the biosynthesis of MCs in Microcystis cells could be attributed to the regulation of mcy gene transcription. Moreover, the MC concentration was decreased significantly after exposure to different intensities of UV-B radiation. Of the three MC variants (MC-LR, -RR and -YR, L, R and Y are abbreviations of leucine, arginine and tyrosine), MC-LR and MC-YR were sensitive to UV-B radiation, whereas MC-RR was not. In summary, our results showed that UV-B radiation had a negative effect on MC production in Microcystis cells and MC persistence in the extracellular space.

Effects of UV-B radiation on germination characteristics in invasive plants in New Zealand

UV-B radiation represents a potentially selective, yet little studied environmental factor for plant invasions, especially with respect to germination characteristics and seedling establishment in areas of high UV-B exposure such as New Zealand. To explain invasive potential of plant species pre-adaptation and local adaptation to selection factors in the invaded range are two frequently consulted concepts. To test for the relevance of these mechanisms, it is necessary to compare both invasive and non-invasive species, as well as native and exotic origins of invasive species. In the present study, germination success of two congeneric species pairs of the genera Verbascum (Scrophulariaceae) and Echium (Boraginaceae) were investigated under high UV-B intensities. Each genus comprised one species that has successfully invaded New Zealand grasslands and one species that was introduced but has not been invasive in New Zealand. In an among-species approach, pre-adaptation was tested by comparing germination success of native (European) origins of all four species in relation to their different invasive success in New Zealand. In a within-species comparison, native (European) and exotic (New Zealand) origins of the two invasive species were compared to test for local adaptation to UV-B in the invaded range. In both approaches, UV-B radiation inhibited the germination success of all study species. However, the comparison of invasive and non-invasive species of the two genera showed no UV-B-specific pre-adaptation of invasive species to high Copyright Maria Hock et al. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. NeoBiota 26: 21–37 (2015) doi: 10.3897/neobiota.26.4405 http://neobiota.pensoft.net RESEARCH ARTICLE Advancing research on alien species and biological invasions A peer-reviewed open-access journal

Sensitivity of post-settlement Dreissena rostriformis bugensis to UVB radiation at Earth surface intensity levels

As quagga mussels (Dreissena rostriformis bugensis) spread through North America, it is critical to understand environmental conditions that may affect their ability to thrive, and thus potentially lead to control measures. The sensitivity of D. r. bugensis to electromagnetic radiation in the Ultraviolet-B range (UVB) is considered through experiment. Post-settlement specimens were collected from Lake Mead (southern Nevada), acclimated to laboratory conditions, and then segregated into two size classes on the basis of length; small (6–9mm) and large (13–19mm). Test groups from both size classes were exposed to continuous UVB at one of three power levels (100, 300, or 500μW/cm2) chosen to be consistent with maximal Earth surface conditions. Survivorship for both size classes was found to follow a logistic model and to scale with the square root of the applied UVB intensity. This result strongly suggests that a four-fold increase in applied power is required to double the mortality rate. Results also strongly suggest that resistance to UVB increases with size/maturity. Post-mortem measurements of shell thickness and UVB transmission demonstrate that the shells impede transmission of UVB with an effectiveness that is proportional to thickness.