硝酸盐还原促进毒害性有机污染物降解的研究进展

大量具有高毒性、持久性和生物蓄积性的有机污染物被排放到环境中,对生态环境和人类健康造成了严重威胁。近年来,利用硝酸盐作电子受体在厌氧条件下降解毒害性有机污染物,已取得一定的进展。本文综述了硝酸盐还原体系中几种典型毒害性有机污染物(多环芳烃、单环或杂环芳烃类有机物及卤代有机物)的厌氧降解研究进展。在此基础上,提出了硝酸盐还原促进毒害性有机污染物降解研究中存在的主要问题及其在加速污染环境净化方面的应用前景。     

有机污染环境的植物修复研究进展

分析了近年来国内外的文献资料,对有机污染物污染环境的植物修复研究进展作了综述。植物能通过根系从环境中吸收和积累PCBs、PAHs等有机污染物,并将吸收的TNT、TCE及有机农药降解为高极性产物、水和CO2;另一方面植物根际可促进有机污染物的根际生物吸收与,使植物对有机污染环境的修复效果更明显。文中探讨了有机污染环境的植物修复技术的优势、问题与未来的研究。     

Evaluation of chiroptical properties of molecules by asymmetric photochemistry

The physics involved in photochemistry with circularly polarized light, the warnings on its inherent limitations, as well as some examples of application on organic molecules are briefly reviewed.     

Proteins and saccharides of the sea urchin organic matrix of mineralization: characterization and localization in the spine skeleton

Properties of the echinoderm skeleton are under biological control, which is exerted in part by the organic matrix embedded in the mineralized part of the skeleton. This organic matrix consists of proteins and glycoproteins whose carbohydrate component is specifically involved in the control mechanisms. The saccharide moiety of the organic matrix of the spines of the echinoid Paracentrotus lividus was characterized using enzyme-linked lectin assays (ELLAs). O-glycoproteins, different types of complex N-glycoproteins, and terminal sialic acids were detected. Sialic acids are known to interact with Ca ions and could play an important role in the mineralization process. Some of the carbohydrate components detected by ELLAs as well as two organic matrix proteins (SM30 and SM50) were localized within different subregions of the spine skeleton using field-emission scanning electron microscopy. The mappings show that some of these components are not homogeneously distributed in the different skeletal subregions. For example, some N-glycoproteins were preferentially located in the putative amorphous subregion of the skeleton, whereas some O-glycoproteins were localized in the subregion where skeletal growth is inhibited. These results suggest that the biological control exerted on the skeletal properties can be partly modulated by local differences in the organic matrix composition.     

Inhibitory effect of organic carbon on CO₂ fixing by non-photosynthetic microbial community isolated from the ocean

The inhibitory effect of organic carbon on CO₂ fixation (CF) by the non-photosynthetic microbial community (NPMC) and its mechanism were studied. The results showed that different concentrations of glucose inhibited CF to some extent. However, when these microorganisms pre-cultured with glucose were re-cultured without organic carbon, their CF efficiency differed significantly from the control based on the glucose concentration in the pre-culture. ATP as bioenergy and NADH as reductant had no obvious inhibitory effect on CF; conversely, they improved CF efficiency to some extent, especially when both were present simultaneously. These results implied that not all organic materials inhibited CF by NPMC, and only those that acted as good carbon sources, such as glucose, inhibited CF. Moreover, some metabolites generated during the catabolism of glucose by heterotrophic metabolism of NPMC might inhibit CF, while other cumulated materials present in the cell interior, such as ATP and NADH, might improve CF.     

持久性有机污染土壤的植物修复及其机理研究进展

随着人类对化学品的依赖程度越来越高,环境的有机污染状况也越来越严重.有机污染土壤的植物修复是指利用植物在生长过程中,吸收、降解、钝化有机污染物的一种原位处理污染土壤的方法,具有应用成本低、生态风险小、对环境副作用小等特点.本文综述了近年来国内外有机污染土壤的植物修复研究进展情况,重点介绍了多氯联苯、多环芳烃、农药和硝基芳香化合物等持久性有机污染物的植物修复,阐述了有机污染土壤植物修复的关键机制,并分析了该技术在实际工程应用中的局限性及应考虑的因素.最后,指出了今后该领域的重点研究方向.     

The utilization of organic nitrogen compounds as sole nitrogen source by some freshwater phytoplankters

Seven organic compounds containing nitrogen were tested as potential sources of nitrogen for five different species of freshwater algae. The chlorococcal green algae Selenastrum and Ankistrodesmus were the most versatile with regard to nitrogen sources; the diatom Cyclotella also grew well upon some organic nitrogen compounds. The desmid Arthrodesmus grew fast only on urea, while Cryptomonas did not grow well upon any of the organic compounds tested.
More information is needed before the potential importance of organic nitrogen sources for freshwater phytoplankton can be assessed.     

土壤活性有机碳的表征及其生态效应

土壤活性有机碳指在一定的时空条件下,受植物、微生物影响强烈、具有一定溶解性、在土壤中移动比较快、不稳定、易氧化、分解、易矿化,其形态,空间位置对植物、微生物来说活性比较高的那一部分土壤碳素。国外描述这一部分碳素的术语为有效碳、水溶性碳、易氧化碳、可矿...     

Origins of life: A comparison of theories and application to Mars

The field of study that deals with the origins of life does not have a consensus for a theory of life's origin. An analysis of the range of theories offered shows that they share some common features that may be reliable predictors when considering the possible origins of life on another planet. The fundamental datum dealing with the origins of life is that life appeared early in the history of the Earth, probably before 3.5 Ga and possibly before 3.8 Ga. What might be called the standard theory (the Oparin-Haldane theory) posits the production of organic molecules on the early Earth followed by chemical reactions that produced increased organic complexity leading eventually to organic life capable of reproduction, mutation, and selection using organic material as nutrients. A distinct class of other theories (panspermia theories) suggests that life was carried to Earth from elsewhere — these theories receive some support from recent work on planetary impact processes. Other alternatives to the standard model suggest that life arose as an inorganic (clay) form and/or that the initial energy source was not organic material but chemical energy or sunlight. We find that the entire range of current theories suggests that liquid water is the quintessential environmental criterion for both the origin and sustenance of life. It is therefore of interest that during the time that life appeared on Earth we have evidence for liquid water present on the surface of Mars.     

Inhibitory effect of dissolved organic matter on triplet-induced oxidation of aquatic contaminants.

Excited triplet states of organic chromophores, in particular aromatic ketones, are capable of inducing oxidation of a variety of organic compounds. These reactions probably play an important role in the degradation of organic contaminants in sunlit natural waters. The effect of dissolved natural organic matter (DOM) on the oxidation rate of twenty-two aquatic organic contaminants, including phenols, anilines, phenylurea and s-triazine herbicides, and some pharmaceuticals, was investigated using photoexcited benzophenone-4-carboxylate (CBBP) as the oxidant. For about half of the studied compounds, a decrease in depletion rate was observed in the presence of Suwannee River fulvic acid, used as a reference DOM. Also, depletion rates decreased with increasing DOM concentration, as verified for five selected compounds. Such an inhibitory effect of DOM on oxidation is attributed to its antioxidant properties, whereby oxidation intermediates of the contaminants are supposed to be reduced back to their parent compounds. The presented screening study shows that DOM may be a relevant factor for inhibiting the oxidation of many organic contaminants in surface waters and possibly in engineered water treatment systems.     

Possible effect between the molecular packing of collagen and the composition of bony tissues

The weight fractions of the organic, mineral and water components of bone have been shown to be uniquely related to the wet bone density, except for a small variation possibly due to structure, for the range of bone densities from 1.7 g/cm³ for deer antler to 2.7 g/cm³ for porpoise petrosal. In this report the mathematical expression for the organic weight fraction is shown to depend on three factors, each a function of bone density. The first factor can be ralated to the mineral fraction, the second to the volume fraction of the organic component and the third to the density of the organic component. The influence of these factors is not obvious, since the change in the organic weight fraction could be due to an absolute loss of organic matter alone, or to a combination of increased mineral concentration together with some loss of organic matter. The mathematical development is based on the generalized packing model for collagen. It is demonstrated that the mineralization process requires a decrease of the organic component as well as a compaction of the collagen fibrils and these vary with the bone density.     

Occurrence,Formation and Function of Organic Sheets in the Mineral Tube Structures of Serpulidae (Polychaeta,Annelida)

A scanning electron microscopy study of organic sheets in serpulid tube mineral structures was carried out to discern their function, formation and evolution. The organic sheets may have some taxonomic value in distinguishing the two major clades of serpulids previously identified. The organic sheets in the mineral tube structure occur only in certain taxa belonging to clade A, but not all species in clade A have them. Organic sheets are best developed in genus Spirobranchus. One could speculate that organic sheets have evolved as an adaption to further strengthen the mechanical properties of the tubes in clade A, which contains serpulids with the most advanced mineral tube microstructures. The organic sheets are presumably secreted with at least some mineral phase.     

Extraction of mitochondrial membrane proteins into organic solvents in a functional state

Protein-lipid complexes in organic solvents can be used as the starting material in the reassembly of functional planar and spherical bilayers (Montal, M., Darszon, A. and Schindler, H. (1981) Q. Rev. Biophys. 14, 1-79). The transfer of three enzymes of the inner mitochondrial membrane into organic solvents as protein-lipid complexes has been studied to understand better the extraction process. The enzymes studied were cytochrome c oxidase, ATPase and succinate dehydrogenase. These enzymes were transferred into hexane and diethyl ether in an active state, however, the activities extracted varied quantitatively, depending on the amount of protein of the starting preparation, the concentration of phospholipids and the cation employed. In all conditions cytochrome c oxidase was extracted with the highest yield and specific activity, and it was actually enriched in the organic extract. The values for succinate dehydrogenase and ATPase were lower, but their specific activities were similar to those of the starting material. This indicates that some membrane proteins are preferentially extracted into organic solvents in a functional state. The enzymes, as protein-lipid complexes, are fairly stable in organic solvents; in a month of storage at 4 degrees C in hexane some enzymes loose less than 50% of their activity.     

Importance of corn extract components for the biosynthesis of polymyxin B by B. polymyxa strain 1538]

The effect of some components of corn-steep liquor, such as biotin, organic nitrogen, inorganic phosphorus and other mineral elements on biosynthesis of polymyxin B by B. polymyxa, strain 1538 was studied. It was found that biotin and organic nitrogen had the most significant effect on the antibiotic accumulation. The effect of inorganic phosphorus and other mineral elements on accumulation of polymyxin by B. polymyxa, strain 1538 was less significant.     

腐殖质在环境污染物生物降解中的作用研究进展

腐殖质物质在地球的生态环境中大量存在,它不仅可以在有毒化合物的生物降解和生物转化过程中起到氧化还原中间体的作用,加速有毒物质的降解和转化。也可以作为唯一末端电子受体,接受来自一些有机酸或者甲苯等环境中有毒物质提供的电子,偶联能量的产生,支持菌体的生长,形成一种新的细菌厌氧呼吸形式——腐殖质呼吸。因此,对腐殖质在环境有毒物质的生物降解和生物转化过程中的作用进行研究,不仪对于深入理解细菌呼吸的本质具有重要的理论意义,而且对于环境有毒物质的降解和转化以及元素的生物地球化学循环具有重要的生态学意义,同时对地球表面的有毒物质进行更有效的生物降解具有重要的现实意义。     

Enzymatic dehydrogenation of steroids by beta-hydroxysteroid dehydrogenase in a two-phase system

The catalytic activity of β-hydroxysteroid dehydrogenase on 3β- or 17β-hydroxysteroids was studied when the reaction was carried out in a two-phase system where the enzyme and the cofactor were in the water phase and the substrate was predominantly in the organic phase.With some organic solvents the enzyme displayed its activity over a long period. Large amounts of steroids could be transformed in small volumes, using low enzyme concentrations.The kinetics of the reaction in the two-phase system as a function of substrate, enzyme concentrations, and pH as well as the equilibrium position were examined.     

利用CENTURY模型研究东北黑土有机碳的动态变化Ⅰ．自然状态下土壤有机碳的积累

应用CENTURY模型,对自然状态下的黑土有机碳库进行了模拟．结果表明,在自然状态下,黑土有机碳库经历了一个由快到慢的增长过程,经过长时间积累,趋向于稳定状态．0～20cm表层土壤有机碳总量最后稳定在7914．72～11672．78g·m^-2．黑土有机碳从北向南总的趋势是逐渐降低．达到稳定状态时,活性土壤有机碳库、慢分解土壤有机碳库和惰性土壤有机碳库分别占土壤全碳的3．36％～4．62％、50．54％～55．47％和36．47％～41．95％,可见慢分解和惰性组分库的增长对土壤有机碳库的积累起到了重要作用．模型模拟结果与已发表的实测结果比较接近,可以为进一步研究开垦后黑土有机碳变化提供依据．     

Trends in soil fractal parameters caused by accumulation of soil organic matter as resulting from the analysis of water vapor adsorption isotherms

The experimental adsorption isotherms are used to evaluate the specific surface area and the surface fractal dimensions of several samples containing organic matter. The aim of the investigations has been to search for correlations between specific surface area and geometrical heterogeneity, as characterized by the surface fractal dimension and the content of organic matter. Besides natural organic soils (peats, forest humuses and brown coal from mines) we also investigate controlled systems obtained by adding humic acids to kaolin and quartz, organic compost to soils and by mixing sandy soil and peat at different ratios. The aim of the investigations of controlled systems was to discover some general trends in the dependencies of the specific surface area and the surface fractal dimension on the content of organic matter.     

Uselessness and indirect negative effects of an insecticide on rice field invertebrates

Macro-invertebrate assemblages on organic and conventional rice fields were quantitatively compared in the Camargue (Rhone delta, France). There was no major difference in family richness, but significant differences as regard to abundance. Fipronil, the insecticide used to control chironomid larvae, was one of the main factors explaining those differences. Its negative impact on predatory invertebrates appears to explain the paradoxical lack of difference in chironomid abundance between organic and conventional fields, observed during the study. Macro-invertebrate biomass estimation showed that, for some birds such as herons, conventional rice fields offered a lower value as foraging habitats than organic ones.     

蚯蚓粪对黄瓜苗期土传病害的抑制作用

试验表明,蚯蚓对农业有机废弃物进行生物降解的产物－蚯蚓粪,在一定程度上能够控制蔬菜类黄瓜苗期土传病害的发生,并表现出明显的促生长效应,蚯蚓粪控制病害的程度与蚯蚓粪的量有一定的关系,当蚯蚓粪与土体积比为20％时,控制病的程度最大,防效达96．1％,这种作用主要与蚯 蚓粪中的微生物性质有关,蚯蚓粪能大大提高土壤中的微生物量和微生物活性,从而大大增强了病土中与病原菌进行能源竞争的微生物的竞争能力,同时从新鲜蚯蚓粪中成功分离到拮抗活性强,抗菌谱广的拮抗微生物,初步研究结果说明,一般性抑制和特殊性抑制两种机制在蚯蚓粪对病害的控制中起作用。