利用脂肪酶提高鱼油中多不饱和脂肪酸(PUFAs)甘油酯

利用脂肪酶选择性的水解作用研究提高鱼油中多不饱和脂肪酸(PUFAs)甘油酯的含量.通过对5种不同来源脂肪酶的筛选,以来源于米曲霉脂肪酶为最佳酶种;同时研究该酶水解鱼油的最佳工艺条件:反应温度、加酶量、反应转速、添加剂影响;最后确定最佳的富集PUFAs甘油酯时间.在此工艺条件下,鱼油中EPA由3.0%提高到9.0%,DHA由4.3%提高到16.5%,EPA DHA由7.3%提高到25.5%.图3表1参8     

Factors affecting vigilance within wild mixed-species troops of saddleback (<Emphasis Type="Italic">Saguinus fuscicollis</Emphasis>) and moustached tamarins (<Emphasis Type="Italic">S. mystax</Emphasis>)

We examine vigilance within a mixed-species troop of saddleback (Saguinus fuscicollis) and moustached (S. mystax) tamarins over a complete year. Saddleback tamarins were consistently more vigilant than moustached tamarins. This may be linked to their preference for lower strata. In accordance with previous studies of other primates, vigilant tamarins of both species were significantly further away from their nearest neighbours, and were also at lower heights in the forest than non-vigilant individuals. There was no observed sex difference in the amount of time spent vigilant. In terms of modes of scanning, the saddleback tamarins looked up significantly more frequently than the moustached tamarins, whereas there was no difference between the species in the frequency of side sweeps. There were no differences between the sexes in the frequencies of either type of vigilant behaviour. The proportion of time spent vigilant was higher than average immediately prior to entering a sleeping site for saddleback tamarins, but not for moustached tamarins. Both species were more vigilant immediately after exiting a sleeping site than at other times of the day. There was significant variation in the amount of time devoted to vigilance over the course of the year. These findings are discussed with respect to the social structure, ecology and main predator threats facing these species.Communicated by D. Watts     

GIS技术在区域土壤有机碳储量估算方面的应用--以柴达木盆地为例

目前在估算土壤有机碳储量方面的方法较多,并且都有其各自的特点所在。地理信息系统(GIS)技术作为当今一种在地学统计分析方面具有强大空间分析功能的计算机应用技术,在地学及相关研究领域得到了广泛的应用。文章首次尝试了利用该技术估算柴达木盆地土壤有机碳储量,该方法与其它计算方法相比,有简单、易操作、可视性好等优点。经计算,柴达木盆地的土壤有机碳储量约为62754.442 t,土壤平均碳面密度为6.105 kgm-2。     

水生细菌对原生动物的反捕食对策

The research progress in the defense strategies of aquatic bacteria to protozoa was reviewed in this paper, Aquatic bacteria can reduce or avoid grazing mortality from protozoa through changing size or shape, reducing cell surface hydrophobieity, reducing mobility or searching refuges. It is the main trends of the field in the future to study the coevolution mode of aquatic bacteria and protozoa. Ref 47     

Ultraviolet-H2O2 oxidation of surfactants

This paper describes a study of the treatment of surfactant synthetic solutions by chemical and photolytic oxidation. Synthetic solutions of linear alkylbenzene sulfonates (LAS) are treated in this work as this is a model compound commonly used in the formulation of detergents, with a great presence in urban and industrial waste-waters. The application of ultraviolet (UV) radiation combined with hydrogen peroxide to oxidize linear alkylbenzene sulfonates (LAS) is shown to be suitable as a primary oxidation step since conversions of about 50% of the original compounds are achieved in the most favorable cases. Initially, the influence of the operating variables on the degradation levels is analyzed in this work. A kinetic model that considers the contributions of both direct photolysis and radical attack is also worked out. Direct photolysis is performed to determine the quantum yield in the single photodecomposition reaction. In addition, the rate constant of the reaction between hydroxyl radicals and linear alkylbenzene sulfonates in the oxidizing system H₂O₂/UV is determined for different operational conditions. Finally, the contribution of each oxidation pathway is quantified, resulting in a higher contribution of the radical reaction than of photolysis in all cases.     

植物线粒体基因转录水平表达研究方法的建立

以茎瘤芥雄性不育系为材料,在已有文献的基础上,对常规方法进行改进,使植物线粒体分离、线粒体切片观察、线粒体RNA提取、反转录方法、PCR扩增、northern杂交等方法系统化,建立了一整套比较有效的适合于植物线粒体基因转录水平表达分析的方法.图4参12     

制约湖南地区节能建筑发展的主要因素及应对技术研究

根据湖南地区节能建筑的发展现状和问题,比较国际建筑节能方面的一些先进经验,通过工程设计实例,探讨建筑产业可持续发展这一关键环节的重要性及其改进措施,并预测了节能建筑在我省的发展态势。     

Phylogenetics of American scallops (Bivalvia: Pectinidae) based on partial 16S and 12S ribosomal RNA gene sequences

Pectinids constitute one of the most conspicuous groups of marine bivalves, and include some of the most important species from the point of view of fisheries and aquaculture. In spite of this, their systematics and evolution are not well understood. Only two molecular phylogenetic analyses based on relatively wide taxonomic samplings have been published. These studies largely neglected American species, some of which are central for testing current models of pectinid evolution and diversification, or are commercially valuable. We have sequenced 820 nucleotide base pairs of the 12S and 16S ribosomal RNA genes in nine species of pectinids belonging to six genera living along American coasts. Sequences from homologous regions of 19 other species were gathered from public databases. We constructed phylogenetic maximum-parsimony and maximum-likelihood trees of this set of 28 taxa. Our phylogenetic analysis indicates that Crassadoma is polyphyletic, and cementation to the substrate as a life habit could have appeared independently in two geographic chlamydinid lineages. Nodipecten is placed in the subfamily Pectininae, and the suspected close relationship of Amusium, Euvola and Pecten within this subfamily is also supported. Zygochlamys patagonica appears in the Chlamydinae subfamily, as expected. The existence of a separate subfamily Palliolinae is suggested but not supported statistically. The position of Argopecten, Aequipecten and Flexopecten within the subfamily Pectinidae, suggested by a recent study, could not be confirmed, and we argue that it could be due to a combination of long branch attraction and incomplete sequencing.     

Analysis of chromium and copper by cathodic stripping voltammetry with mixed ligands

Cathodic adsorptive stripping voltammetry is one of the most sensitive analytical methods for ultratrace analysis. The detection limit is usually lower than 10⁻⁹ mol/L. Most adsorptive stripping procedures have been focused on the one ligand/one analyte approach. In order to reduce analysis time and sample volume, the possibility of simultaneously determining several metals by cathodic stripping voltammetry using a mixture of ligands was explored, e.g., by Colombo and van den Berg (1997). Here, we describe a new procedure for quantifying chromium and copper using 2,2′-bipyridine and 8-hydroxyquinoline (oxine). The effect of various operational parameters such as buffer type, ligand concentration, potential and time collection were assessed and optimized. Possible interferences by trace metals and organic matter were also investigated. Applicability for fresh water is illustrated. Electronic Publication