杨木低聚木糖对肉鸡生长性能、肠道消化酶活性和短链脂肪酸含量及血清激素水平的影响

本试验以肉鸡为研究对象,对以杨木屑为原料、采用醋酸催化法制取的低聚木糖进行评价,研究低聚木糖对肉鸡生长性能、肠道消化酶活性和短链脂肪酸含量及血清激素水平的影响,探讨低聚木糖的促生长机制,为醋酸催化法生产低聚木糖的应用提供理论依据.选用120只1日龄爱拔益加肉公鸡,随机分为2个组,即对照组和低聚木糖组,每组6个重复,每个...     

6种白腐菌腐朽前后的山杨木材酚酸种类和含量变化的高效液相色谱分析

研究阔叶树上的6种木材白腐菌火木层孔菌、粗毛盖菌、偏肿拟栓菌、三色革裥菌、冬拟多孔菌和血红密孔菌对山杨材腐朽前后木材中游离酚酸种类和含量的变化情况.结果表明:受6种白腐菌腐朽后的山杨木材中酚酸的种类和含量各不相同,在山杨材被分解120 d后,偏肿拟栓菌、三色革裥菌、血红密孔菌和冬拟多孔菌的9种游离酚酸总含量远大于粗毛盖菌和火木层孔菌的9种游离酚酸总含量,表明前4种对木质素分解能力较强的菌种获得了较高含量的酚酸;但从9种游离酚酸总的含量上看,与各菌种对木材和木质素的分解百分率不尽相同,初步分析的原因表明在木质素被分解的过程中除了有这9种游离酚酸产生以外,可能还会产生其他的游离酚酸以及苯环二聚体、三聚体和各种寡聚体以及杂环的形式,所有这些苯环结构总体造成了对木质素分解百分率的差异. 对9种酚酸进行分析测试,只构成对木质素分解的一部分,不足以用来解释对木质素的全部分解能力,其他的酚酸和游离酚酸以外的苯环结构还有待进一步研究分析测试;从各种游离酚酸单个含量上看,各种白腐菌的种类和含量都各不相同,表明不同白腐菌对同一木质纤维基质的分解途径、中间降解产物各不相同.另外,未腐朽的木材中本身就含有一些微量的酚酸成分,这些酚酸在生物分解过程中会降解和转化成其他成分, 是否有可能转化成其他种类的酚酸还有待进一步证明.     

腐殖酸结合汞的研究现状

综述了近20年来国内外对腐殖酸结合汞的研究成果。腐殖酸在土壤中虽然含量不高 ,但结合汞的容量大 ,且结合汞后有一定的活性。并指出 ,人们对腐殖酸结合汞是抑制还是活化土壤汞的认识分歧在于腐殖酸组分对汞的络合能力和络合物稳定性存在差异。     

设施油桃果实发育过程中糖酸代谢的研究

以设施内超红株油桃果实为试材,测定果实中可溶性糖、有机酸含量及相关代谢酶活性。结果表明,果实发育早期糖分积累以还原糖即葡萄糖和果糖为主;果实发育后期,还原糖含量下降,蔗糖含量迅速升高,蔗糖合成酶（SS）和蔗糖磷酸合成酶（SPS）活性呈上升趋势;有机酸与苹果酸含量均呈先升高后降低趋势,柠檬酸含量呈逐渐上升趋势;果实发育后期苹果酸酶（ME）活性逐渐升高,苹果酸舍量呈下降趋势;苹果酸脱氢酶（MDH）活性呈先升高后降低趋势,与苹果酸含量变化趋势相似。说明SS和SPS与蔗糖积累有关,MDH与苹果酸合成有关,ME与苹果酸降解有关。     

笃斯越桔叶营养成分分析

对笃斯越桔叶中的氨基酸，微量元素，维生素，糖类，有机酸等营养成分进行分析，并对部分不同采收期的叶成分进行了对比，为开发利用笃斯越桔叶提供了科学的依据。     

New Extracellular Bacillus subtilis Lectins with Sialic Acid-Specificity

The purpose of this work is to perform a detailed study of carbohydrate specificity of the new extracellular bacilli lectins which is considered to determine mechanisms of the lectins action. Sources of lectins were bacterial strains from Ukrainian collection of microorganisms. The optimized protocol of bacilli lectins isolation and purification included precipitation with ammonium sulfate with subsequent gel filtration chromatography on Sepharose CL-6B. Hemagglutinating activity of bacilli lectins and their fine carbohydrate specificity to sialic acids and their derivatives as well as sialic asid-containing and asialic glycoconjugates were studied. The ability of extracellular bacilli lectins to discriminate a- and 13-conformation of carbohydrate molecule and the type of connection between the monomers was determined. Studied lectins showed the most affinity to glycoconjugates containing both types of sialic acids （N-acetylneuraminic acid （Neu5Ac） and N-glycolylneuraminic acid （NeuGc）） and it is supposed to be a basis of their diagnostic and analytical potential.     

南方鲶肌肉,鳔及胡子鲶肌肉的水解和游离氨基酸研究

本试验测定了南方鲶肌内和鳔及胡子鲶肌肉的水解氨基酸和游离氨基酸含量，并对其营养价值进行了比较，评价。     

Introgressive hexaploid oats from the Avena abyssinica (♀) × A. sativa hybrid: performance, grain lipids and proteins

A fertile hexaploid oat plant was obtained after several generations of selection for seed set and plant type from a colchicine-produced decaploid hybrid, Avena abyssinica(2n = 4x = 28, AABB) × A. sativa (2n = 6x = 42, AACCDD). The selected line proved to be stably fertile and in many characteristics equal or superior to the hexaploid parent. The grain protein fractions showed two qualitative differences from those of the pollen parent and several differences from the maternal parent. The fractionating extraction used was new for oats. The fatty acid composition of grains of the hybrid derivative was similar to that of the pollen parent, but different from that of the maternal parent. The maternal parent (A. abyssinica) had a relatively high 16:0 fatty acid content (ca. 20.5 mol%) compared with the level of the hexaploid parent and the hybrid derivation (ca. 17.5 mol% each) in field-grown grain. However, in grain produced in the greenhouse, the hexaploids had ca. 20.5 mol% of 16:0 fatty acid and a decrease in 18:1 fatty acid, whereas seed of the A. abyssinica parent showed only a slight increase (ca.21.5 mol%) in 16:0 fatty acid. These and other responses statistically significant may be due to adaptation to temperature conditions being wider in the hexaploids than in the East-African A. abyssinica. A new method of grain lipid extraction was introduced and showed good reproducibility. The derived hexaploid oat can be crossed with A. sativa for breeding purposes and due to its early maturity might also have direct use in northern or high-altitude cultivation. This revised version was published online in July 2006 with corrections to the Cover Date.     

Mixotrophy in a Local Strain of Nannochloropsis granulata for Renewable High-Value Biomass Production on the West Coast of Sweden

A local strain of Nannochloropsis granulata (Ng) has been reported as the most productive microalgal strain in terms of both biomass yield and lipid content when cultivated in photobioreactors that simulate the light and temperature conditions during the summer on the west coast of Sweden. To further increase the biomass and the biotechnological potential of this strain in these conditions, mixotrophic growth (i.e., the simultaneous use of photosynthesis and respiration) with glycerol as an external carbon source was investigated in this study and compared with phototrophic growth that made use of air enriched with 1–2% CO₂. The addition of either glycerol or CO₂-enriched air stimulated the growth of Ng and theproduction of high-value long-chain polyunsaturated fatty acids (EPA) as well as the carotenoid canthaxanthin. Bioassays in human prostate cell lines indicated the highest antitumoral activity for Ng extracts and fractions from mixotrophic conditions. Metabolomics detected betaine lipids specifically in the bioactive fractions, suggesting their involvement in the observed antitumoral effect. Genes related to autophagy were found to be upregulated by the most bioactive fraction, suggesting a possible therapeutic target against prostate cancer progression. Taken together, our results suggest that the local Ng strain can be cultivated mixotrophically in summer conditions on the west coast of Sweden for the production of high-value biomass containing antiproliferative compounds, carotenoids, and EPA.     

不同有机酸对大豆生长的化感效应

试验采用发芽试验、水培试验及室内分析相结合的方法研究了经GC－MS检测出的大豆根系分泌物和根茬腐解液中的几种有机酸对大豆种子萌发及幼苗生长发育的化感效应。结果表明：3－硝基邻苯二甲酸、邻甲氧基苯甲酸、3，4－二氯苯甲酸、肉桂酸等四种有机酸均抑制了大豆种子的萌发，表现在萌发率、胚根长和 胚根干重与对照相比均有所降低，差异达显著或极显著水平，而且有机酸浓度不同，抑制程度也有所差别；3－硝基邻苯二甲酸、邻甲氧基苯甲酸、3，4－二氯苯甲酸、肉桂酸、邻苯二甲酸等五种有机酸不同程度地抑制了水培大豆幼苗的生长发育，表现在株高、干物质重、相对生长速率等均低于对照，差异达显著或极显著水平，且随着有机酸浓度的增加，抑制作用增强。