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真菌漆酶的性质、生产及应用研究进展 总被引:1,自引:0,他引:1
《生物技术通报》2016,(4)
作为一种含铜的多酚氧化酶,真菌漆酶比细菌漆酶、植物漆酶等具有更好的热稳定性、金属离子耐受性及更高的底物催化氧化性,在工农业及环境领域的应用中得到了较高的关注。目前普遍认为,限制漆酶广泛应用的因素在于漆酶的生产规模、成本与性质。真菌漆酶的生产模式包括固态发酵和液体发酵,工业生产基本以液体发酵为主。除了在染料脱色、染织废水处理、纸浆漂白等过程中的应用,最新的研究不断拓展了漆酶新的用途,对近年来真菌漆酶的发酵生产、酶学性质及应用研究中的最新结果进行了概述。 相似文献
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中国生漆化学成分研究 总被引:2,自引:0,他引:2
生漆作为天然高分子材料在我国应用已有6000多年的历史.其主要化学成分为漆酚、漆酶和漆多糖.提取分离并研究这些物质的化学组成、生物活性功能是多年来生漆化学研究的热点之一.总结了20多年来国内外关于漆酚、漆酶和漆多糖分离提取方法及漆多糖生物活性的最新研究进展. 相似文献
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《生物技术通报》2017,(10)
漆酶是一种含铜离子的多酚氧化酶,广泛存在于植物及真菌中。漆酶含特有的铜离子,其功能为传递结构中的电子,使漆酶具有了较强的氧化还原能力,能与木质素、胺类化合物、芳香化合物等底物发生作用,且大多数反应的唯一产物为水。目前,漆酶在降解多种有毒物质和有害污染物方面表现出高效、成本较低的特性,如白腐真菌所产的高水平漆酶已广泛成熟应用在工业废水处理等生物整治和修复领域。近年来最新研究利用载体固定化酶的技术使漆酶能够在使用后回收反复利用且更具有稳定性,这降低成本的同时还保持了漆酶催化氧化的特性,克服了不少漆酶在解决环境污染中出现的问题。利用介体的介导作用解决了漆酶氧化还原电势较低的问题,大量增多了可降解底物的种类,使其在废水处理、污染物降解、土壤修复、工业染料漂白等领域的应用前景更广阔。对现有漆酶应用于各领域进行研究总结,综述了降解各领域中的有害污染物等底物种类,提出了利用漆酶的降解过程中的现有不足和改进方向,以期为生物法降解环境污染物的研究提供参考。 相似文献
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一色齿毛菌漆酶的酶学特性及染料脱色研究 总被引:1,自引:1,他引:0
染料由于具有复杂的化学结构通常难以降解。本文从白腐菌一色齿毛菌LS0547中纯化出胞外漆酶并用于染料脱色实验。SDS-PAGE结果显示纯化的漆酶分子量大小为63.7kDa。漆酶氧化底物ABTS的最适pH为2.2,最适温度为50℃。叠氮钠可强烈抑制漆酶活性,半胱氨酸和二硫苏糖醇可部分抑制漆酶活性。漆酶氧化ABTS,丁香醛连氮和2,6-二甲氧基苯酚的米氏常数分别为0.217,0.306和0.199mmol/L。粗酶和纯化的漆酶用于不同化学结构的染料的脱色研究,结果表明一色齿毛菌纯化漆酶可快速对RB亮蓝进行脱色,偶氮胭脂红和结晶紫的脱色效果低于RB亮蓝,测试的三种染料均可在没有介体存在的条件下被漆酶脱色,显示出一色齿毛菌漆酶在染料废水处理中的应用前景。 相似文献
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Mitochondrial complex III regulates hypoxic activation of HIF 总被引:3,自引:0,他引:3
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The coupled conservation of mass equations for oxygen, carbon dioxide and nitrogen are written down for a lung model consisting of two homogeneous alveolar compartments (with different ventilation-perfusion ratios) and a shunt compartment. As inspired oxygen concentration and oxygen consumption are varied, the flux of oxygen, carbon dioxide and nitrogen across the alveolar membrane in each compartment varies. The result of this is that the expired ventilation-perfusion ratio for each compartment becomes a function of inspired oxygen concentration and oxygen consumption as well as parameters such as inspired ventilation and alveolar perfusion. Another result is that the "inspired ventilation-perfusion ratio and the "expired ventilation-perfusion ratio differ significantly, under some conditions, for poorly ventilated lung compartments. As a consequence, we need to distinguish between the "inspired ventilation-perfusion distribution, which is independent of inspired oxygen concentration and oxygen consumption, and the "expired ventilation-perfusion distribution, which we now show to be strongly dependent on inspired oxygen concentration and less dependent oxygen consumption. Since the multiple inert gas elimination technique (MIGET) estimates the "expired ventilation-perfusion distribution, it follows that the distribution recovered by MIGET may be strongly dependent on inspired oxygen concentration. 相似文献
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Allaway William G. Curran Mark Hollington Lauren M. Ricketts Malcolm C. Skelton Nicholas J. 《Wetlands Ecology and Management》2001,9(3):221-228
Aerenchyma pervades the cortex of the whole root system in Avicenniamarina var. australasica plants grown for 3 to 5 years in artificial-tidaltanks. The gas spaces appear to be schizogenous in all but the finest roots,where some apparently lysigenous gas spaces develop. Gas spaces in thepith are small. Pneumatophores examined at the time the tips are growingpossess subrisules on the tips as well as lenticels on mature regions. At othertimes subrisules are not seen. When the tide floods the pneumatophores,gas pressure and oxygen concentration go down – pressure by 1.7 kPa orless, but oxygen by as much as 3 mol m-3, or more in some cases.On draining, pressure recovers immediately to atmospheric, but oxygenslowly rises to a plateau below the concentration in the atmosphere. Thechanges in oxygen concentration are consistent with oxygen supply bydiffusion. The contribution of oxygen made by the small influx of air onpressure recovery is only a minor fraction of the respiratory oxygenrequirement. Wet weather at low tide restricts gas exchange, affecting bothpressure and oxygen. The pressure and oxygen changes are repeated overmany tidal cycles. The results are compared with those for other speciesand situations in the literature. 相似文献
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Yoshii H Yoshii Y Asai T Furukawa T Takaichi S Fujibayashi Y 《Biochemical and biophysical research communications》2012,417(1):640-645
Carotenoids, natural pigments widely distributed in algae and plants, have a conjugated double bond system. Their excitation energies are correlated with conjugation length. We hypothesized that carotenoids whose energy states are above the singlet excited state of oxygen (singlet oxygen) would possess photosensitizing properties. Here, we demonstrated that human skin melanoma (A375) cells are damaged through the photo-excitation of several carotenoids (neoxanthin, fucoxanthin and siphonaxanthin). In contrast, photo-excitation of carotenoids that possess energy states below that of singlet oxygen, such as β-carotene, lutein, loroxanthin and violaxanthin, did not enhance cell death. Production of reactive oxygen species (ROS) by photo-excited fucoxanthin or neoxanthin was confirmed using a reporter assay for ROS production with HeLa Hyper cells, which express a fluorescent indicator protein for intracellular ROS. Fucoxanthin and neoxanthin also showed high cellular penetration and retention. Electron spin resonance spectra using 2,2,6,6-tetramethil-4-piperidone as a singlet oxygen trapping agent demonstrated that singlet oxygen was produced via energy transfer from photo-excited fucoxanthin to oxygen molecules. These results suggest that carotenoids such as fucoxanthin, which are capable of singlet oxygen production through photo-excitation and show good penetration and retention in target cells, are useful as photosensitizers in photodynamic therapy for skin disease. 相似文献
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Temperature-sensitive oxygen carriers that are responsive to changes in temperature while maintaining colloidal stability would benefit physiological conditions characterized by tissue hypoxia due to decreased body temperature. These conditions are often accompanied with reduced blood flow and vasoconstriction. Temperature-sensitive oxygen carriers should ideally possess increased oxygen affinity when the body temperature is reduced, to selectively target tissues that are hypoxic as a result of temperature drops. This study expands on previous work, which introduced hydrogel based oxygen carriers as a new class of oxygen carrier that can be synthesized within liposomal reactors via photoinitiated free radical polymerization [Patton, J. N.; Palmer, A. F. Biomacromolecules 2005, 6, 414-24]. In addition to the ability of poly(N-isopropylacrylamide) hydrogel nanoparticles encapsulating bovine hemoglobin to swell and shrink in response to physiological changes in temperature, the effect of temperature changes on zeta potential, oxygen affinity, and cooperativity are also examined. The methemoglobin level and hemoglobin encapsulation efficiency of hydrogel-based oxygen carriers are also presented. It was observed that nanoscale hydrogel particles swelled as the temperature decreased from 40 to 29 degrees C, which suggests expansion of the hydrogel matrix and reduced resistance to oxygen transport. 相似文献
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Quantitative aspects of oxygen uptake by Gammarus (Crustacea, Amphipoda): a critical review 总被引:1,自引:0,他引:1
D. W. SUTCLIFFE 《Freshwater Biology》1984,14(5):443-489
SUMMARY. Gill structure and function are brietly considered, as are the main factors affecting the oxygen content of water. The review deals with quantitative, analytical aspects of oxygen uptake related to body size, temperature, oxygen content of water, salinity, water velocity, substratum and activity of Cammarus. A theoretical model relates oxygen uptake to growth and life-span of individuals. Several aspects of regression analysis, as applied to measurements of oxygen uptake, are examined and constructively criticized. The energetic cost of osmoregulation is calculated for G. pulex. The review concentrates on freshwater species of Gammarus but work on brackish-marine species is also included. A more detailed summary and conclusions are given at the end of the review. 相似文献
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E. Newton Harvey 《The Journal of general physiology》1922,5(2):215-222
It can be demonstrated by an indicator method that living cells are as freely permeable to oxygen as dead cells, and that sudden admission of oxygen to the cell cannot account for increased oxidation as a result of stimulation. Oxygen penetrates as readily as carbon dioxide among the acids and ammonia among the alkalies. Exposure of living plant cells to high oxygen pressures does not initiate certain oxidations (except after some hours), which proceed readily in dead plant cells in the air. In the light of the preceding statement, about the permeability of cells for oxygen, this is interpreted to mean that more oxygen enters the cell at high pressure, but that the reacting substances (chromogen and oxidase) are kept apart by some phase boundary as long as the cell is alive. Increased oxygen concentration eventually produces injury to the cell. 相似文献
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Toxic oxygen species and protective systems of the chloroplast 总被引:14,自引:0,他引:14
Marvin L. Salin 《Physiologia plantarum》1988,72(3):681-689
Salin, M. L. 1988. Toxic oxygen species and protective systems of the chloroplast. -Physiol. Plant. 72: 681–689.
As a consequence of living in an environment enriched in oxygen, which they themselves at least partially generate, photosynthetic organisms are exposed to large fluxes of oxyradicals and reactive oxygen species. Among these are superoxide, hydrogen peroxide, hydroxyl radical and singlet oxygen. These highly reactive intermediates pose the threat of toxicity unless neutralized by scavenger substrates or enzymes. The production of oxyradicals and intermediates by chloroplasts as well as the means of protection are discussed in this review. 相似文献
As a consequence of living in an environment enriched in oxygen, which they themselves at least partially generate, photosynthetic organisms are exposed to large fluxes of oxyradicals and reactive oxygen species. Among these are superoxide, hydrogen peroxide, hydroxyl radical and singlet oxygen. These highly reactive intermediates pose the threat of toxicity unless neutralized by scavenger substrates or enzymes. The production of oxyradicals and intermediates by chloroplasts as well as the means of protection are discussed in this review. 相似文献
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This article examines the geological evidence for the rise of atmospheric oxygen and the origin of oxygenic photosynthesis.
The evidence for the rise of atmospheric oxygen places a minimum time constraint before which oxygenic photosynthesis must
have developed, and was subsequently established as the primary control on the atmospheric oxygen level. The geological evidence
places the global rise of atmospheric oxygen, termed the Great Oxidation Event (GOE), between ~2.45 and ~2.32 Ga, and it is
captured within the Duitschland Formation, which shows a transition from mass-independent to mass-dependent sulfur isotope
fractionation. The rise of atmospheric oxygen during this interval is closely associated with a number of environmental changes,
such as glaciations and intense continental weathering, and led to dramatic changes in the oxidation state of the ocean and
the seawater inventory of transition elements. There are other features of the geologic record predating the GOE by as much
as 200–300 million years, perhaps extending as far back as the Mesoarchean–Neoarchean boundary at 2.8 Ga, that suggest the
presence of low level, transient or local, oxygenation. If verified, these features would not only imply an earlier origin
for oxygenic photosynthesis, but also require a mechanism to decouple oxygen production from oxidation of Earth’s surface
environments. Most hypotheses for the GOE suggest that oxygen production by oxygenic photosynthesis is a precondition for
the rise of oxygen, but that a synchronous change in atmospheric oxygen level is not required by the onset of this oxygen
source. The potential lag-time in the response of Earth surface environments is related to the way that oxygen sinks, such
as reduced Fe and sulfur compounds, respond to oxygen production. Changes in oxygen level imply an imbalance in the sources
and sinks for oxygen. Changes in the cycling of oxygen have occurred at various times before and after the GOE, and do not
appear to require corresponding changes in the intensity of oxygenic photosynthesis. The available geological constraints
for these changes do not, however, disallow a direct role for this metabolism. The geological evidence for early oxygen and
hypotheses for the controls on oxygen level are the basis for the interpretation of photosynthetic oxygen production as examined
in this review. 相似文献