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101.
Bueno M Fillat MF Strasser RJ Maldonado-Rodriguez R Marina N Smienk H Gómez-Moreno C Barja F 《Environmental science and pollution research international》2004,11(2):98-106
INTENTION, GOAL, SCOPE, BACKGROUND: Cyanobacteria have the natural ability to degrade moderate amounts of organic pollutants. However, when pollutant concentration exceeds the level of tolerance, bleaching of the cells and death occur within 24 hours. Under stress conditions, cyanobacterial response includes the short-term adaptation of the photosynthetic apparatus to light quality, named state transitions. Moreover, prolonged stresses produce changes in the functional organization of phycobilisomes and in the core-complexes of both photosystems, which can result in large changes in the PS II fluorescence yield. The localization of ferredoxin-NADP+ reductase (FNR) at the ends of some peripheral rods of the cyanobacterial phycobilisomes, makes this protein a useful marker to check phycobilisome integrity. OBJECTIVE: The goal of this work is to improve the knowledge of the mechanism of action of a very potent pesticide, lindane (gamma-hexaclorociclohexane), in the cyanobacterium Anabaena sp., which can be considered a potential candidate for bioremediation of pesticides. We have studied the effect of lindane on the photosynthetic apparatus of Anabaena using fluorescence induction studies. As ferredoxin-NADP+ reductase plays a key role in the response to oxidative stress in several systems, changes in synthesis, degradation and activity of FNR were analyzed. Immunolocalization of this enzyme was used as a marker of phycobilisome integrity. The knowledge of the changes caused by lindane in the photosynthetic apparatus is essential for rational further design of genetically-modified cyanobacteria with improved biorremediation abilities. METHODS: Polyphasic chlorophyll a fluorescence rise measurements (OJIP) have been used to evaluate the vitality and stress adaptation of the nitrogen-fixing cyanobacterium Anabaena PCC 7119 in the presence of increasing concentrations of lindane. Effects of the pesticide on the ultrastructure have been investigated by electron microscopy, and FNR has been used as a marker of phycobilisome integrity. RESULTS AND DISCUSSION: Cultures of Anabaena sp. treated with moderate amounts of lindane showed a decrease in growth rate followed by a recovery after 72 hours of pesticide treatment. Concentrations of lindane below 5 ppm increased the photosynthetic performance and activity of the cells. Higher amounts of pesticide caused a decrease in these activities which seems to be due to a non-competitive inhibition of PS II. Active PS II units are converted into non-QA reducing, so called heat sink centers. Specific activity and amount of FNR in lindane-treated cells were similar to the values measured in control cultures. Release of FNR from the thylakoid after 48 hours of exposure to 5 ppm of lindane towards the cytoplasm was detected by immunogold labeling and electron microscopy. CONCLUSIONS: From these results, we conclude that the photosynthetic performance and activity of the cells are slightly increased in the presence of lindane up to 5 ppm. Moreover, in those conditions, lindane did not produce significant changes in the synthesis, degradation or activity of FNR. The high capability of Anabaena to tolerate lindane makes this cyanobacterium a good candidate for phytoremediation of polluted areas. RECOMMENDATION AND OUTLOOK: The results of this study show that cultures of Anabaena PCC 7119 tolerate lindane up to 5 ppm, without significant changes in the photosynthetic vitality index of the cells. However, a slight increase in phycobiliprotein synthesis is observed, which is related to total protein content. This change might be due to degradation of proteins less stable than phycobiliproteins. An identification of the proteins with altered expression pattern in the presence of the pesticide remains the subject of further work and will provide valuable information for the preparation of strains which are highly tolerant to lindane. 相似文献
102.
103.
离体培养植物细胞的表面与细胞粘连 总被引:3,自引:0,他引:3
对离体培养的胡萝卜(Daucuscarota)细胞和普通烟草(Nicotianatabacum)细胞的表面进行了扫描电镜观察.观察表明,细胞的自由表面上有很多疣突和纤丝.疣突的大小不同、形状各异,主要含果胶质;有些细胞表面出现小坑,坑中集中有许多微小颗粒.疣突相互可融合成更大的疣突或连成桥;纤丝常与疣突结合.纤丝-纤丝的交织,纤丝-疣突的交联,及疣突-疣突的融合,在细胞壁外表面构成交织的网络.同种细胞之间及异种细胞之间均可通过纤丝、疣突的交织融合而粘连.疣突分布不均一,且与细胞的分散性有关.与疏松烟草愈伤组织比较,致密烟草愈伤组织细胞的自由表面上疣突显著较多.在分化再生时,烟草愈伤组织首先致密变绿,然后才见到芽的分化及植株再生.对疣突出现、壁物质沉积与细胞粘连、细胞分化、形态建成几者之间的关系进行了讨论. 相似文献
104.
除油水力旋流器在九江石化厂的应用 总被引:3,自引:0,他引:3
除油水力旋流器是一种管道式油水分离设备 ,它具有体积小 ,无须特殊维护等特点。针对炼油装置的具体特点 ,提出了旋流器的配置流程 ,并结合在九江石化总厂的使用经验 ,验证了旋流器在炼油装置应用的可行性 ,同时提出了具体使用时应注意的问题。 相似文献
105.
Plant species composition and species number were studied in two types of field margins: 31 arable field margins and 33 road verges. Both field margin types were adjacent to intensively managed grass or cereal fields. Effects of eight variables on field margin vegetation were studied. Despite having many plant species in common, composition and species number differed between the two field margin types, due to different ecological conditions and margin management. Arable field margins were composed of tall and/or nutrient demanding ubiquitous species and were characterised by species of later successional stages than those of road verges. The vegetation of road verges was lower and species numbers were higher than in arable field margins. The road verges contained several semi-natural meadow species that are declining in abundance. A CCA ordination of the field margins and the recorded variables showed that plant species composition was significantly affected by thickness of litter, slope, width, moisture level and type of crop in the adjacent field. Number of plant species was significantly higher in mown than unmown margins and generally higher in margins adjacent to fields with mainly grass production than in margins adjacent to fields with mainly cereal crops. In order to preserve botanical diversity in this agricultural landscape, the maintenance of regularly mown road verges should be prioritized. 相似文献
106.
107.
植树造林已普遍作为减缓全球变暖的主要对策之一,其主导思想是利用森林的光合作用吸收大气中的CO_2。目前很少人注意到缓解全球变暖的另一种途径,即从森林生物量中获取替代矿物燃料的生物能源。 相似文献
108.
以农业农村部环境监测总站对我国主要叶菜类蔬菜产地的例行监测数据为基础,综合考虑种类和土壤理化性质的影响,深入探讨了应用物种敏感性分布法(SSD)基于不同累积概率建立我国叶菜类蔬菜产地“优先保护类、安全利用类和严格管控类”的土壤镉环境质量类别划分阈值,并对其合理性验证.结果表明:pH值、阳离子交换量(CEC)和土壤有机质(SOM)对叶菜类蔬菜富集镉的影响均达到了极显著水平(P<0.01),并由其构建的三因子生物有效性模型为lgBCF=-0.122pH+0.025lgSOM-0.048lgCEC+1.252(R2=0.746,P<0.01,n=134),可解释叶菜类蔬菜富集系数74.6%的变异;利用上述模型将不同土壤理化性质条件下叶菜类蔬菜镉的生物富集系数(BCF)归一化处理可最大程度降低土壤理化性质对其富集镉的影响,凸出叶菜类蔬菜的内在敏感性;利用归一化后的BCF通过log-logistic拟合函数构建SSD曲线得到,不同叶菜类蔬菜种类对镉的敏感性差异明显;依据SSD曲线基于保护80%、50%和5%的叶菜类蔬菜种类分别推导出pH≤6.5、6.5相似文献
109.
The research presents the first results of aluminium speciation analysis in aqueous extracts of individual plant parts of Betula pendula and soil samples, using High Performance Ion Chromatography with Diode Array Detection(HPIC-DAD). The applied method allowed us to carry out a full speciation analysis of aluminium in the form of predominant aluminium–fluoride complexes: AlF_((x = 2,3,4))~((3-x))(first analytical signal), AlF~(2+)(second analytical signal) and Al~(3+)(third analytical signal) in samples of lateral roots, tap roots, twigs, stem, leaf and soil collected under roots of B. pendula. Concentrations of aluminium and its complexes were determined for two types of environment characterised by different degree of human impact:contaminated site of the Chemical Plant in Luboń and protected area of the Wielkopolski National Park. For all the analysed samples of B. pendula and soil, AlF_((x = 2,3,4))~((3-x))had the largest contribution, followed by Al~(3+)and AlF~(2+). Significant differences in concentration and contribution of Al–F complexes and Al~(3+)form, depending on the place of sampling(different anthropogenic pressure) and plant part of B. pendula were observed. Based on the obtained results, it was found that transport of aluminium is "blocked" by lateral roots, and is closely related to Al content of soil. 相似文献
110.