涉及光疗机制的生物光化学

本文对光生物和光化学的定义,反应机制的类型和光敏化作用等做了阐述。下面例举几个光疗的成果 1.光疗牛皮癣 经常使用的8-甲氧基补骨脂素在UVA的照射下,从基态被激发到三重态。它主要和DNA中的胸腺嘧啶,其次和色氨酸进行光环合加成,形成交联,阻止DNA和RNA的合成,抑制具过度增生 2.血卟啉衍生物(HPD)治癌 HPD有定位于癌组织的能力和光动力作用,可推断病人体内癌部位。 讨论了HPD的光疗机制,和酞菁相比,有各自的优缺点。 3.竹红菌素 主要治疗妇女外阴白色病变和疤痕疙瘩,抑制癌细胞生长。 讨论了竹红菌甲素和乙素及它们的氧化物的结构和活性。 在大于510nm的光照射下,也可抑制癌细胞的生长。列举了竹红菌素的优缺点。

生物光化学中的几个问题

生物光化学是光生物学的基础。生物光化学归根结底是光感受体(即感光的物质)的光化学。但是光感受体范围极广,功能各异,例如有感受紫外光的生物大分子(如蛋白质与核酸);有感受长波紫外光的糠香豆素类物质;有感受可见光的视紫质类物质(如视觉中的视紫质,嗜盐菌紫膜中的菌紫质);

烟酰胺腺嘌呤二核苷酸磷酸与生物光化学

生物光化学的核心内容是光合作用。在光合作用这个生物光化学的核心领域 ,烟酰胺腺嘌呤二核苷酸磷酸 (NADPH)始终起着极其重要的作用 ,NADPH就是一个传递电子和能量的最关键活性生物分子。本文对海洋里的光合作用、细菌与光合作用以及光合作用的模拟等作了介绍。

基于荧光增强效应的可逆型牛血清白蛋白光化学生物传感器研究

研究了一种具有可逆响应的蛋白质生物传感器。敏感层由丙烯酰胺荧光素固定于硅烷化的平面波导上形成 ,然后装配在自制的流通池中并用光导纤维连入荧光分光光度计 ,结果发现牛血清白蛋白 (BSA)对此敏感膜有明显的荧光增强反应 ,在 0 .4～ 2 0 μmol/L 范围内敏感膜的荧光增强度与BSA的浓度呈线性关系 ,检测下限为 0 1μmol/L。并且此传感器无需特殊的试剂对其进行再生 ,等电点不同的蛋白质引起的荧光增强程度也不同 ,常见的金属离子对测定无影响 ,但重金属离子对测量有较大的影响。对传感器的响应机理也进行了多方面的分析 。

中国照明学会光生物、光化学专业委员会召开工作会议

2016年5月13日,中国照明学会光生物光化学专业委员会在北京召开工作会议,有20余位委员出席了会议,中国照明学会副理事长郝洛西、副秘书长高飞出席了会议,杨铭主任主持了会议。会议首先由杨铭主任通报了近一年来委员会的工作：2015年10月参加了中国科协主办、中国照明学会承办的海峡两岸光生物、光化学青年科学家论坛;

核酸光化学生物学

光敏感基团作为光化学开关被广泛应用于各种生物过程的光调控中。特别是过去十几年内,核苷酸、寡聚核苷酸和DNA/RNA的光敏修饰策略得到了长足的发展,并在细胞信号传导和靶基因的功能调控等诸多生物学研究中发挥重要的作用。本文主要针对常用的光敏感基团、光敏感核酸及其化学生物学研究进展进行简要综述,并对未来核酸光化学生物学的研究进行了展望。

不同来源有色溶解性有机物光化学/微生物降解过程

城市非点源污染向水生生态系统中输入大量的溶解有机物(DOM),对生态系统健康产生重要影响.有色可溶性有机物(CDOM)是广泛分布于自然水体中的一类成分和结构复杂、含有多种高活性化学官能团的大分子聚合物,是DOM的重要组分,对水生生态系统健康、能量流动及生物地球化学循环有重要影响.光化学反应和微生物代谢过程被认为是控制水体CDOM转化、降解和循环的主要影响因素.然而,对城市化如何影响CDOM组成以及光化学和微生物如何相互作用影响城市水体CDOM动态的理解是不足的.因此,为评估光化学过程和微生物代谢对不同城市水体CDOM降解与转化的贡献,解析不同城市水体CDOM光化学/微生物降解作用机理,本研究在英国伯明翰选择3类具有典型DOM来源的水体样本,通过实验室9 d受控培养实验,对比分析光化学以及微生物影响下CDOM来源和组成的变化.结果表明:(1)城市河流由于接受上游污水排放及较短的水力滞留时间,含有丰富的芳香性碳,其CDOM光化学活性明显高于湖泊,光化学降解率为16.60%;(2)城市湖泊CDOM受人类活动影响,自生源类荧光成分富集,生物活性高,在微生物培养过程中CDOM增加了62.16%,而相较于城市湖泊,非城市湖泊由于接受周围景观土壤输入的大量腐殖质类CDOM,光照对其降解转化作用较为明显;(3)光化学过程促进了陆源CDOM中大分子类腐殖质物质降解成为生物活性高的小分子化合物,刺激微生物代谢生成类蛋白质类有机物;以类蛋白质组分为主导的CDOM在光照过程中被转化为难降解状态,生物活性降低,CDOM微生物代谢过程被抑制.研究成果为城市水体不同CDOM来源及活性差异特征研究提供了新的思路,有助于城市河流的可持续开放与管理.

光化学研究进展综述

主要对生物光化学、海洋光化学、环境光化学等进展进行综述,并对光化学应用和发展前景进行展望,提出了今后的重点研究方向。

THE BIOGEOCHEMISTRY OF PHOTOSYNTHETIC PIGMENTS IN THE JIULONG RIVER ESTUARY AND WESTERN XIAMEN BAY

High performance liquid chromatography (HPLC) analysis of photosynthetic pigments in samples from Western Xiamen Bay and the Jiulong River Estuary showed that their major carotenoids were fucoxanthin, peridinin, zeaxanthin, violaxanthin, and diadinoxanthin. Diatoms dominated in the spring bloom, dinoflagellates in summer. Violaxanthin and chlorophyll b indicated the appearance of chrysophytes and green algae, most of which were freshwater species. The high phytoplankton biomass region was located at the inner part of the bay. Diatoms and dinoflagellates dominated phytoplankton communities, contributing to over 50% of total biomass. All the main diagnostic carotenoids were significantly (P<0.01) correlated negatively to dissolved inorganic phosphorus, suggesting that they were limited by phosphorus. The high negative linear relationship (P<0.0001) between dissolved inorganic phosphorus and peridinin (dinoflagellates indicator) implied the potential of dissolved inorganic phosphorus for triggering red tide events in this region.

Dehydrolutein:a metabolically derived carotenoid never observed in raptors

Carotenoids are fat-soluble pigments synthesised by photosynthetic organisms(Brush,1990).Conversely,animals are incapable of synthesizing carotenoids de novo,and they must obtain them through their diet.However,some animal species are able to make some alterations to the basic chemical structure,converting ingested carotenoids into more oxidized and differently coloured forms(Schiedt,1998).

Photochemical Degradation of the Ciprofloxacin Antibiotic and Its Microbiological Validation

In this research, it used advanced oxidation processes for the recovery, detoxification and mineralization of wastewater mainly contaminated by antibiotics （ciprofloxacin）. These processes can be used alone or in combination with each other or by complementing traditional methods, even allowing the disinfection of bacterial and viral inactivation. With the use of experimental systems UV/H202/O3, UV/H202, it can achieve total mineralization of the compound. Ciprofloxacin solutions used at 50, 100, 200, 300, 400 and 500 ppm, degraded to 100% of antibiotics and by a microbiological method show that the loss of biological activity is inversely proportional to the time of irradiation.

Quantifying biochemical variables of corn by hyperspectral reflectance at leaf scale

To further develop the methods to remotely sense the biochemical content of plant canopies,we report the results of an experiment to estimate the concentrations of three biochemical variables of corn,i.e.,nitrogen(N),crude fat(EE) and crude fiber(CF) concentrations,by spectral reflectance and the first derivative reflectance at fresh leaf scale. The correlations between spectral reflectance and the first derivative transformation and three biochemical variables were analyzed,and a set of estimation models were established using curve-fitting analyses. Coefficient of determination(R2),root mean square error(RMSE) and relative error of prediction(REP) of estimation models were calculated for the model quality evaluations,and the possible opti-mum estimation models of three biochemical variables were proposed,with R2 being 0.891,0.698 and 0.480 for the estimation models of N,EE and CF concentrations,respectively. The results also indicate that using the first derivative reflectance was better than using raw spectral reflectance for all three biochemical variables estimation,and that the first derivative reflectances at 759 nm,1954 nm and 2370 nm were most suitable to develop the estimation models of N,EE and CF concentrations,respectively. In addition,the high correlation coefficients of the theoretical and the measured biochemical parameters were obtained,especially for nitrogen(r=0.948).

Autumn Photoproduction of Carbon Monoxide in Jiaozhou Bay, China

Carbon monoxide(CO) plays a significant role in global warming and atmospheric chemistry. Global oceans are net natural sources of atmospheric CO. CO at surface ocean is primarily produced from the photochemical degradation of chromophoric dissolved organic matter(CDOM). In this study, the effects of photobleaching, temperature and the origin(terrestrial or marine) of CDOM on the apparent quantum yields(AQY) of CO were studied for seawater samples collected from Jiaozhou Bay. Our results demonstrat that photobleaching, temperature and the origin of CDOM strongly affected the efficiency of CO photoproduction. The concentration, absorbance and fluorescence of CDOM exponentially decreased with increasing light dose. Terrestrial riverine organic matter could be more prone to photodegradation than the marine algae-derived one. The relationships between CO AQY and the dissolved organic carbon-specific absorption coefficient at 254 nm for the photobleaching study were nonlinear, whereas those of the original samples were strongly linear. This suggests that: 1) terrestrial riverine CDOM was more efficient than marine algae-derived CDOM for CO photoproduction; 2) aromatic and olefinic moieties of the CDOM pool were affected more strongly by degradation processes than by aliphatic ones. Water temperature and the origin of CDOM strongly affected the efficiency of CO photoproduction. The photoproduction rate of CO in autumn was estimated to be 31.98 μmol m-2 d-1 and the total DOC photomineralization was equivalent to 3.25%- 6.35% of primary production in Jiaozhou Bay. Our results indicate that CO photochemistry in coastal areas is important for oceanic carbon cycle.

Fiber optic biosensor of immobilized firefly luciferase

Luciferase from firefly lantern extract was immobilized on CNBr activated Sepharose 4B. The kinetic properties of immobilized luciferase were extensively studied. The K m′ for D luciferin is 11.9 μmol/L, the optimum pH and temperature for Sepharose bound enzyme were 7.8 and 25℃ respectively. A luminescence fiber optic biosensor, making use of immobilized crude luciferase, was developed for assay of ATP. The peak light intensity was linear with respect to ATP concentration in range of 10 -9 -10 -5 mol/L. A biological application was also demonstrated with the determination of serum ATP from rats bred in low versus normal oxygen environments.

Advances in the Marine Photochemistry of Some Important Transition Metal Elements

Marine inorganic photochemistry, as one of the important branches of marine chemistry, is significantly connected with marine biology, marine ecology, marine geochemistry and marine environment, and plays an important role in the development of marine sciences. To date, lots of investigations in the field have been conducted home and abroad. As for the following development of marine inorganic photochemistry, it is greatly of significance to summarize these research works. This paper detailedly summarizes the present research progress in the photochemistry of Fe, Mn and Cu, with an emphasis on investigations on photochemical processes which could affect existing forms of these metal elements in seawater. The problems and shortcomings in the study field are pointed out and some suggestions for the future study are put forward.

Occurrence and distribution of dissolved tellurium in Changjiang River estuary

With the implementation of the GEOTRACES program, the biogeochemical cycle and distribution of tellurium （Te） in marine environments are becoming increasing environmental concerns. In this study, the concentration of dissolved Te in the Changjiang （Yangtze） River estuary and nearby waters was determined in May 2009 by hydride-generation atomic fluorescence spectrometry to elucidate the abundance, dominant species, distribution, and relationship with environmental factors. Results show that： （1） dissolved Te was low owing to its low abundance in the Earth＇s crust, high insolubility in water, and strong affinity to particulate matter; （2） Te（IV） and Te（VI） predominated in surface water. Te（VI） was the dominant species in bottom water, and Te（IV） was the minor species; （3） Horizontally, resulting from low phytoplankton metabolism and the weak reduction from Te（VI） to Te（IV） in the shore, Te（IV） was concentrated in the central zone instead of the coastal region. However, Te（VI） was abundant near the mouth of the Changjiang River where the Changjiang water is diluted and in the area to the south where the Taiwan Warm Current invaded. In the adsorption-desorption process, Te（IV） was negatively related to suspended paniculate matter （SPM）, indicating that it was adsorbed by particulate matter. While for Te（VI）, the positive correlation with SPM suggested that it was desorbed from the solid phase. In the estuary, dissolved Te had a negative correlation to salinity. However, it deviated from the dilution line in high-salinity regions due to the invasion of the Taiwan Warm Current and the mineralization of organic matter. The relationship between Te（IV） and SPM nutrients indicated that it was more bioavailable and more related to phosphorus than to nitrogen. Progress in the field is slow and more research is needed to quantify the input of Te to the estuary and evaluate the biochemical role of organisms.

Optical closure of parameterized bio-optical relationships

An optical closure study on bio-optical relationships was carried out using radiative transfer model matrix operator method developed by Freie Universitat Berlin. As a case study, the optical closure of bio-optical relationships empirically parameterized with in situ data for the East China Sea was examined. Remote-sensing reflectance （Rrs） was computed from the inherent optical properties predicted by these biooptical relationships and compared with published in situ data. It was found that the simulated Rrs was overestimated for turbid water. To achieve optical closure, bio-optical relationships for absorption and scattering coefficients for suspended particulate matter were adjusted. Furthermore, the results show that the Fournier and Forand phase functions obtained from the adjusted relationships perform better than the Petzold phase function. Therefore, before bio-optical relationships are used for a local sea area, the optical closure should be examined.

Heavy metal content in coral reef sediments from Red Sea of Yemen and its significance on marine environment

In order to determine and assess the concentrations of trace elements in coral reefs sediments from Red Sea of Yemen, sediment samples were collected, treated and analyzed for cadmium, chromium, cobalt, copper, manganese, nickel, lead, iron, zinc and vanadium by the atomic absorption spectrometric analysis. The result is that cadmium, cobalt and lead concentrations were high and other elements are low or the same as natural background. It is concluded that the high cadmium, cobalt and lead levels in coral reefs sediments will have negative effects on marine life of the sites, so further researches are needed to characterize the sources fate, biogeochemical processes and impacts of these trace elements on coral reefs and marine of the region.