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1.
Ana L. Santos Vanessa Oliveira Inês Baptista Isabel Henriques Newton C. M. Gomes Adelaide Almeida António Correia Ângela Cunha 《Archives of microbiology》2013,195(1):63-74
The biological effects of UV radiation of different wavelengths (UVA, UVB and UVC) were assessed in nine bacterial isolates displaying different UV sensitivities. Biological effects (survival and activity) and molecular markers of oxidative stress [DNA strand breakage (DSB), generation of reactive oxygen species (ROS), oxidative damage to proteins and lipids, and the activity of antioxidant enzymes catalase and superoxide dismutase] were quantified and statistically analyzed in order to identify the major determinants of cell inactivation under the different spectral regions. Survival and activity followed a clear wavelength dependence, being highest under UVA and lowest under UVC. The generation of ROS, as well as protein and lipid oxidation, followed the same pattern. DNA damage (DSB) showed the inverse trend. Multiple stepwise regression analysis revealed that survival under UVA, UVB and UVC wavelengths was best explained by DSB, oxidative damage to lipids, and intracellular ROS levels, respectively. 相似文献
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《Bioscience, biotechnology, and biochemistry》2013,77(6):1166-1170
The present study explored the possibility that aroma components generated by the oxidation of olive oil may enhance the palatability of olive oil. Using a mouse behavioral model, we found that olive oil oxidized at room temperature for 3 weeks after opening the package, and heated olive oil were both significantly preferred over non-oxidized olive oil. Furthermore, this preference was enhanced with an additive of oxidized refined olive oil flavoring preparation at a certain concentration. These results suggest that the aroma of oxidized fat might be present in most fats, and might act as a signal that makes possible the detection of fats or fatty acid sources. 相似文献
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Jianjun Chen Zhi Li Ming Lei Xiuli Fu Jinghua Xiao Qihuang Gong 《Plasmonics (Norwell, Mass.)》2012,7(3):441-445
Based on the strongly coupled-resonator effects, a high wavelength-resolution plasmonic Y-splitter, consisting of a Y-branch metal–insulator–metal waveguide with a baffle in each channel, is numerically investigated using the finite element method. Due to the coupling of different resonators (with nearly equal bandwidths) in the Y-splitter, sharp and asymmetric transmission spectra occur. This greatly increases the wavelength resolution of the Y-splitter to be Δλ?≈?15 nm, which is significantly narrower than the bandwidth of the single resonator (Δλ FWHM?≈?110 nm). An analytic model based on the scattering matrix theory is provided to describe and explain this phenomenon. 相似文献
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用M onte-Carlo模拟了波长为515 nm的激光光源在空气-肺-空气层样品结构中的传播,详细地讨论了面光源分别为高斯光束和圆平面光束在不同光束半径情况时的光能流率和漫反射强度的分布情况,并与波长635 nm激光光源的结果相比较。结果表明:不同波长光源在相同模型中传播,其光能流率分布和漫反射强度的分布走向相同,激光光斑形状和光束半径大小的选择对激光在组织中传播有重要的影响作用,但比较模拟结果之后,发现在生物组织中近红外光波相对其他光波的穿透性比较强,更便于生物医学以及其他领域的研究。 相似文献
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《Bioscience, biotechnology, and biochemistry》2013,77(6):1062-1069
Male Sprague-Dawley rats, 4 weeks (young) or 8 months (adult) of age, were fed one of three purified diets free of or containing either 0.5% cholesterol or 0.5% oxidized cholesterol (92% oxidized cholesterol) for 3 weeks. Feeding of oxidized cholesterol caused a significant reduction of food intake, body weight gain, and relative liver weight in rats of both ages. The activity of the HMG-CoA reductase and cholesterol 7α-hydroxylase of liver microsomes, the key enzymes in cholesterol synthesis and catabolism, respectively, was lowered by oxidized cholesterol compared to the diet free of cholesterol in both ages, and the difference was significantly in the adult. On the other hand, the activity of Δ6-desaturase of liver microsomes, a key enzyme in linoleic acid metabolism to arachidonic acid, was significantly increased by oxidized cholesterol in adult rats, leading to the increase in linoleic acid desaturation index [(20:3n-6 + 20:4n-6)/18:2n-6] in liver phospholipids. Oxidized cholesterol reduced the concentration of cholesterol in serum and liver. Also, the fecal excretion of acidic steroids was lower in rats fed the oxidized cholesterol diet than in those fed the cholesterol-free diet. Thus, oxidized cholesterol significantly influenced cholesterol and fatty acid metabolism in particular in adult rats. 相似文献
7.
Dahms HU Dobretsov S Lee JS 《Comparative biochemistry and physiology. Toxicology & pharmacology : CBP》2011,153(4):363-371
Ozone-related increase in solar ultraviolet radiation (UVR) during the last decades provided an important ecological stressor, particularly for polar ecosystems since these are less adapted to such changes. All life forms appear to be susceptible to UVR to a highly variable extent that depends on individual species and their environment. Differences in sensitivity between organisms may relate to efficiency differences of their protection mechanisms and repair systems. UVR impacts are masked by large seasonal and geographic differences even in confined areas like the polar regions. UVR has effects and responses on various integration levels: from genetics, physiology, biology, populations, communities, to functional changes as in food webs with consequences on material and energy circulations through ecosystems. Even at current levels, solar UV-B affects consumer organisms, such as ectotherms (invertebrates and fish), particularly through impediments on critical phases of their development (early life history stages such as gametes, zygotes and larvae). Despite the overall negative implications of UVR, effect sizes vary widely in, e.g., molecular damage, cell and tissue damage, survival, growth, behavior, histology, and at the level of populations, communities and ecosystems. 相似文献
8.
Effects of Light Intensity and Oxidized Nitrogen Sources on Hydrogen Production by Chlamydomonas reinhardii
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Chlamydomonas reinhardii cells, after a period of dark anaerobic adaptation, evolve H2 not only in the dark but also in the light. Our results show that high irradiances impair prolonged H2 evolution, while under low irradiances or darkness H2 evolution proceeds for more than 50 hours. NO3− and NO2− suppress H2 evolution both in the dark or under low irradiance. Apparently the cells prefer these oxidized nitrogen sources to protons as electron acceptors, since both NO3− and NO2− become reduced to NH4+, which is excreted to the culture medium in high amounts. H2 evolution started once these oxidized anions were largely depleted from the medium. Moreover, H2 evolution was consistently associated with NH4+ excretion even if NH4+ was already present in high amounts in the medium. This observation indicates that the cells utilize not only their carbohydrate but also their protein reserves as sources of reducing power for H2 evolution. This conclusion was supported by the observation that when nitrogen-starved cells were made anaerobic in a nitrogen-free medium, they not only evolved H2 at very high rates but excreted concomitantly NH4+ up to concentrations in the millimolar range. 相似文献
9.
紫外线作为重要的环境因子之一,能显著影响包括白念珠菌在内的多种生物的生长及生理过程.研究发现白念珠菌受紫外线照射后菌丝形成被抑制,孢子形成增多且没有向光性;脉冲紫外线辐射可通过多靶点程序使白念珠菌失活;rad 51缺陷株比rad 52缺陷株更易受紫外线损害,同时紫外线可导致白念珠菌杂合性丢失.研究还发现UVC治疗可明显减少烧伤后真菌微生物感染,核黄素/UVA治疗可明显抑制白念珠菌生长.因此紫外线对白念珠菌有一定的抑制作用. 相似文献
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At present, information on the effects of ultraviolet radiation (UVR) on structure and diversity of polar, in particular Arctic,
benthic communities is scarce. It is unclear whether and to what extent communities of different successional age are susceptible
to UVR and whether UVR effects known to be detrimental at the species level can be buffered at the community level. In a subtidal
field study on Spitsbergen (Norwegian Arctic), we investigated the potential effect of distinct UVR regimes on macrobenthic
communities of different successional ages, grown on ceramic tiles. Total taxon cover, taxon composition, evenness, and richness
were assessed after experimental exposure of 4 and 8 weeks. Overall, 17 algal and invertebrate taxa were encountered in the
study and diatoms dominated the communities regardless of successional age or radiation treatment. UVR effects were dependent
on both exposure time and community age. We did not find overall detrimental UVB effects. In contrast, abundance of several
species increased in UVR-exposed communities. Especially, UVA seemed to have a beneficial effect in that several green and
brown algal taxa increased in abundance (e.g. Ulothrix flacca, Chlorophyta, and Desmarestia sp., Phaeophyceae). In general, UVR effects depended on species composition and thus on successional age of communities,
with later successional communities likely to be able to buffer and alleviate possible negative effects of UVR at species
level. Overall, the presented study provides a first insight into the complex role UVR plays in structuring Arctic epibenthic
communities. 相似文献
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氧化棉子糖分子内交联猪血红蛋白对其结构功能的影响 总被引:3,自引:3,他引:3
用高碘酸盐氧化法制得氧化开环棉子糖,并用它分别修饰处在氧合及脱氧构象的猪血红蛋白得到两种不同的修饰衍生物。与天然蛋白质相比,两种修饰后的猪血红蛋白衍生物均具有明显的抗α2β2四聚体解聚的特性。经SDS-PAGE和反相HPLC分析发现这两种修饰衍生物均为分子内交联产物,而且交联都发生于2个β亚基之间,两种交联产物的紫外-可见光谱没有明显差别,但在相同浓度下,脱氧构象下被修饰蛋白质的荧光发射光强度明显 相似文献
14.
Effects of UV Radiation on Photolyase and Implications with Regards to Photoreactivation following Low- and Medium-Pressure UV Disinfection
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Photolyase activity following exposure to low-pressure (LP) and medium-pressure (MP) UV lamps was evaluated. MP UV irradiation resulted in a greater reduction in photolyase activity than LP UV radiation. The results suggest that oxidation of the flavin adenine dinucleotide in photolyase may have caused the decrease in activity. 相似文献
15.
The Effects of Streptomycin, Desiccation, and UV Radiation on Ice Nucleation by Pseudomonas viridiflava 总被引:3,自引:1,他引:3
Streptomycin (100 micrograms per milliliter), desiccation (over CaSO4), and ultraviolet radiation (4500 microwatts per square centimeter at 254 nanometers for 15 minutes) reduced ice nucleation activity by Pseudomonas viridiflava strain W-1 as determined by freezing drops of the bacterial suspensions. Highest residual ice nucleation activity by dead cells was obtained by desiccation, although no freezing above −3.5°C was detected. The rate and extent of loss of ice nucleation activity following streptomycin and ultraviolet treatment was affected by preconditioning temperature. At 21°C and above, loss of activity by dead cells was rapid and irreversible. 相似文献
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制备成年(8~12周龄)和老年(64~72周龄)SD大鼠血清,实验随机分为两组:年轻血清组和老年血清组,分别采用成年和老年SD大鼠血清培养成年MSCs 36小时后,衰老相关β-半乳糖苷酶和活性氧染色观察细胞衰老,MTT法检测细胞增殖,AO/EB法和Hoechst 33342染色法观察细胞凋亡及存活情况。免疫细胞化学和Western blot法检测衰老相关蛋白γ-H2A.X、p53表达,RT-PCR法观察p53、p21 mRNA表达。结果发现,与年轻血清组相比,老年血清组MSCs衰老细胞数明显增加((96.2±24.1)/500细胞vS(30.8±8.2)/500细胞,P<0.01)、增殖能力减弱,凋亡率升高,γ-H2A.X、p53蛋白表达水平升高,p53、p21 mRNA表达升高。这些结果说明、老年SD大鼠血清可促进MSCs发生衰老变化,并抑制MSCs增殖及存活能力,这一作用可能与DNA损伤反应和p53/p21信号通路有关。 相似文献
17.
体细胞来源及培养代数对核移植重构胚发育的影响 总被引:2,自引:0,他引:2
为探讨体细胞来源及培养代数对核移植重构胚发育的影响,实验采用电融合法将小鼠2—细胞胚胎卵裂球、胚胎干细胞(ES)、胎儿成纤维细胞、耳成纤维细胞、尾尖成纤维细胞、睾丸支持细胞和精原细胞以及不同培养代次的胎儿成纤维细胞进行了核移植。结果显示:2—细胞胚胎卵裂球供核重构胚发育最好,囊胚率为7.4%;ES细胞重构胚虽然发育率低,但仍有囊胚出现,比例为0.7%;胎儿成纤维细胞重构胚最高发育阶段为桑椹胚,比例为0.2%;精原细胞重构胚只能发育到8-细胞阶段,比例为0.3%;其他几类细胞重构胚则仅能发育至4-细胞阶段。不同培养代数的胎儿成纤维细胞重构胚除第3代外都可发育到8-细胞阶段,且发育率差异不显著,但第一代细胞重构胚2-细胞发育率(40.7%)显著低于2、3和4代细胞重构胚。结果表明:不同分化程度的细胞核移植后,重新编程的难易程度是不一样的,分化程度越高则重新编程越难;未调整细胞周期的ES细胞由于多数处于S期,所以重构胚发育率很低;体外培养传代有利于体细胞核移植后重新编程。 相似文献
18.
Toshihiro Nakanishi Takehiko Yamamoto 《Bioscience, biotechnology, and biochemistry》2013,77(9):1797-1802
The sites on oxidized insulin B-chain substrate initially attacked by an alkalophilic proteinase from a Streptomyces sp., were investigated under incubation conditions employing one part enzyme to one thousand parts of substrate at 0°C.Analysis of the peptides produced after 10 to 40 seconds of incubation revealed that the enzyme, which has an optimum pH of around 13, first attacks two peptide linkages “-Leu (15)Tyr (16)-Leu (17)-” of the oxidized insulin B-chain with equal efficiency. 相似文献
19.
Maura Floreani Marcella Petrone Patrizia Debetto Pietro Palatini 《Free radical research》1997,26(5):449-455
In this study, three rapid assay techniques for the determination of glutathione, one enzymatic, one flu-orometric and one newly patented colorimetric method, were compared by measuring reduced (GSH) and oxidized (GSSG) glutathione in guinea-pig heart and liver. The HPLC technique was used as a standard, since it is considered the most reliable assay method. In heart, all methods measured the same levels of GSH (about 1 µmole/g wet tissue), whereas in liver the fluorometric assay gave GSH levels about half as high as those measured by the other methods (about 3 vs. 7 µmoles/g wet tissue). Conversely, the fluorometric assay grossly overestimated GSSG concentration (by 5 to 8 times) in both heart and liver. These results confirm previous doubts about the use of the fluorometric technique for GSSC determination in mammalian tissues and also raise some questions about its use for the measurement of GSH in liver. In this tissue, the GSH concentration determined by the fluorometric method was shown to be inversely correlated with the size of the sample, suggesting the presence of some quenching material. 相似文献
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Mohammed M. Al Gadban Kent J. Smith Farzan Soodavar Christabelle Piansay Charlyne Chassereau Waleed O. Twal Richard L. Klein Gabriel Virella Maria F. Lopes-Virella Samar M. Hammad 《PloS one》2010,5(9)