薄层色谱法分离植物种子中主要不饱和脂肪酸的研究

测定植物种子中主要不饱和脂肪酸,在油脂品质鉴定、营养研究、油料作物品种选育(特别是油菜)以及发掘新的有价值的油料植物资源等方面,都有重要意义。现在检测菜籽油芥酸含量的方法有:气相色谱法、纸色谱法、冷冻法、分步沉淀法和混浊法。用于分离较长链不饱和脂肪酸的方法除了气相色谱     

稻米色氨酸测定方法的改进

<正> 色氨酸是动物和人体中八种必需氨基酸之一,它对人和动物的生长发育、新陈代谢起着重要的作用,被称为第二必需氨基酸。目前测定蛋白质的氨基酸多采用氨基酸分析仪及气相色谱法测定其水解产物,这种方法需要昂贵的仪器,且在水解过程中色氨酸完全被破坏,尤其是象水稻这些含碳水化合物高的粮食作物,水解时即使采取了添加保护剂的办法,色氨酸的破坏仍是严重的,     

饲料中三聚氰胺的测定研究

本文就饲料中三聚氰胺的检测方法做一些探讨。目前对饲料中的三聚氰胺的检测,主要有酶免疫法,高效液相色谱法,高效液相色谱-质谱法和气相色谱-质谱法。本文就这些检测方法进行探讨,对其优缺点进行研究。在这些检测方法中,目前比较实用的方法是高效液相色谱-质谱法。     

病毒单糖的研究 Ⅰ.颗粒体病毒(GV)单糖的气相色谱分析

本文介绍了颗粒体病毒中单糖的气相色谱分析法,对所得病毒单糖色谱图中的主要组分进行了分析鉴定,证明组成病毒的单糖成分有:鼠李糖、核糖、木糖、甘露糖、葡萄糖和阿拉伯糖。并用相应单糖峰高比值,区分了它们间的异同。病毒单糖分析结果。能与血清学和裂解气相色谱法分析鉴定病毒的结果相符。     

真菌生物量指示剂麦角固醇的分离及测定方法*

麦角固醇作为真菌细胞膜的重要组成成分,结构稳定,可作为真菌生长的指示物质。综述了表征真菌生物量的麦角固醇的分离及测定方法,其中麦角固醇的萃取方法有传统的皂化回流法、快速物理萃取、超声波萃取、超临界流体萃取等,测定方法有高效液相色谱法、气相色谱-质谱法、液相色谱-质谱法、薄层色谱法等。并对这些方法的应用及在堆肥过程中运用麦角固醇估计真菌生物量的可行性进行了展望。     

高原鼢鼠扰动及恢复年限对高寒草甸土壤养分和微生物功能多样性的影响

为了研究高原鼢鼠扰动后退化高寒草甸恢复演替的动态过程,利用常规实验室分析方法和Biolog-ECO生态板法对青藏高原东缘高寒草甸土壤养分和微生物功能多样性进行分析.结果表明: 高原鼢鼠扰动显著降低了土壤有机质、全氮、速效氮和速效磷含量,对土壤全磷和全钾含量无显著影响;在一定植被恢复年限内,土壤微生物的碳源利用率、Shannon、Pielou和McIntosh指数随着植被恢复年限的增加而升高;主成分分析表明,碳水化合物和氨基酸是土壤微生物利用的主要碳源类型;冗余分析表明,土壤pH、有机质、全氮、速效氮和全钾是影响土壤微生物代谢活性和功能多样性的主要因子.不同植被恢复年限土壤微生物功能多样性的变化可能是对地上植被、土壤微生物群落组成和土壤养分变化的响应.     

棒曲霉素检测方法研究进展

棒曲霉素(Patulin)是由部分曲霉、青霉等霉菌产生的次级代谢产物,主要污染水果及其制品.本文时目前常见检测方法薄层色谱法(TLC)、微乳电动色谱法(MEECK)、液相色谱法(LC)、液相色谱-质谱法(LC-MS)、气相色谱-质谱法(GC-MS)、和免疫法等进行了分析.棒曲霉素属小分子弱抗原物质,很难免疫动物,描述了用噬菌体抗体库筛选棒曲霉素抗体来开发ELISA快速检测试剂盒用于现场检测的优越性,并就噬菌体抗体库技术用于小分子弱抗原物质抗体筛选前景进行了展望.     

真菌生物量指示剂麦角固醇的分离及测定方法

麦角固醇作为真菌细胞膜的重要组成成分,结构稳定,可作为真菌生长的指示物质。综述了表征真菌生物量的麦角固醇的分离及测定方法,其中麦角固醇的萃取方法有传统的皂化回流法、快速物理萃取、超声波萃取、超临界流体萃取等,测定方法有高效液相色谱法、气相色谱-质谱法、液相色谱-质谱法、薄层色谱法等。并对这些方法的应用及在堆肥过程中运用麦角固醇估计真菌生物量的可行性进行了展望。     

固相微萃取-气质法测定土壤挥发性抑菌物质*

运用固相微萃取 气相色谱 质谱法 (SPME GC MS) ,测定了参与土壤抑真菌作用的土壤挥发性成分和土壤细菌挥发性代谢物。通过比较土壤来源和土壤细菌来源的挥发性抑菌成分 ,发现在强挥发性抑菌土壤和土壤细菌代谢物中普遍存在着三甲胺、二甲基二硫醚、3 甲基 2 戊酮、甲基吡嗪、 2 ,5 二甲基吡嗪、N ,N 二甲基辛胺、十九烷等化合物。这些化合物很有可能就是参与土壤抑菌作用 ,特别是挥发性物质抑菌作用的主要成分。另外 ,为深入了解土壤中参与抑菌作用的挥发性化合物提供了简便有效的方法。     

四川凉山烤烟叶片巨豆三烯酮含量与生态因子的关系

基于四川省凉山州9个烟叶主产区土壤与烟叶各81个样品的实验室测试数据,应用逐步回归分析、偏相关分析和通径分析方法,研究了生态因子与烤烟叶片中巨豆三烯酮含量的数量关系,结果表明,月平均气温、月平均降雨量、≥20℃积温、土壤有机质、土壤水解氮、土壤速效钾和土壤pH值是影响烤烟烟叶巨豆三烯酮含量的主要生态因子,彼此互相关联,共同决定了烤烟叶片巨豆三烯酮含量变化的98.02%.对烤烟叶片巨豆三烯酮含量直接影响最大的是月平均降雨量,其次是土壤有机质、月平均气温、≥20℃积温、土壤速效钾、土壤pH值和土壤水解氮,其中月平均降雨量对烤烟叶片巨豆三烯酮含量产生直接的负面效应,而土壤有机质、月平均气温则对烤烟叶片巨豆三烯酮含量产生直接的正面效应.土壤有机质是烤烟叶片巨豆三烯酮含量最主要的促进因素,而≥20℃积温是烤烟叶片巨豆三烯酮含量最主要的限制因素.     

Rapid screening procedures for identification of succinic acid producers

Succinic acid, an intermediate of tricarboxylic acid cycle, is produced and accumulated by anaerobic microorganisms. The long-standing interest in the production of this organic acid is because it is a key compound in producing more than 30 commercially important products. The detection of succinic acid is generally carried out by gas chromatography (GC), enzymatic assays, ion-exclusion chromatography (IEC) or by high performance liquid chromatography (HPLC). However, these methods are time consuming, require sophisticated instrumentation and are expensive. In the present investigation we are reporting two rapid, cost effective screening methods for the detection of this important organic acid. These methods can be utilized to screen a large number of microbes producing succinic acid in a very short span of time.     

Diagnostic methods for the determination of iduronic acid in oligosaccharides

A high-performance liquid chromatography (HPLC) method with pulsed amperometric detection (PAD) was used for the determination of the acid hydrolysis products of L-iduronic acid containing oligosaccharides isolated from biological sources. This HPLC-PAD method was compared with gas chromatographic (GLC) methods. Since acid hydrolysis of oligosaccharides can produce a number of products, several uronic acid derivatives were prepared by chemical synthesis. These well characterized standards in conjunction with mass spectrometry allowed for the identification of most of the products of methanolysis or hydrolysis of glycosamino-glycans, which included chondroitin sulfates A and B (dermatan sulfate), heparin, and hyaluronic acid. (4 M) HCl in methanol 100 degrees C for 24 h was found to be optimum for GLC and 1 M aqueous HCl for 4 h at 100 degrees C for HPLC-PAD. All of the monosaccharides, hexosamines, and uronic acids could be separately identified in a single chromatographic step using either technique. Good resolution, high sensitivity (low microgram samples) and rapid analysis makes these methods particularly useful for the determination of small amounts of glycosaminoglycans and other glycoconjugates found in samples isolated from biological sources. These two techniques are specifically designed to allow the qualitative determination of the carbohydrate content and composition of samples whose carbohydrate composition and content is completely unknown.     

Carbohydrate analysis of water-soluble uronic acid-containing polysaccharides with high-performance anion-exchange chromatography using methanolysis combined with TFA hydrolysis is superior to four other methods.

Sulfuric acid hydrolysis according to the Saeman procedure, TFA hydrolysis, and methanolysis combined with TFA hydrolysis were compared for the hydrolysis of water-soluble uronic acid-containing polysaccharides originating from fungi, plants, and animals. The constituent sugar residues released were subsequently analyzed by either conventional GLC analysis of alditol acetates or high-performance anion-exchange chromatography with pulsed-amperometric detection. It was shown that TFA hydrolysis alone is not sufficient for complete hydrolysis. Sulfuric acid hydrolysis of these polysaccharides resulted in low recoveries of 6-deoxy-sugar residues. Best results were obtained by methanolysis combined with TFA hydrolysis. Methanolysis with 2 M HCl prior to TFA hydrolysis resulted in complete liberation of monosaccharides from pectic material and from most fungal and animal polysaccharides tested. Any incomplete hydrolysis could be assessed easily by HPAEC, by the detection of characteristic oligomeric products, which is difficult using alternative methods currently in use. Methanolysis followed by TFA hydrolysis of 20 micrograms water-soluble uronic acid containing polysaccharides and subsequent analysis of the liberated sugar residues by HPAEC allowed us to determine the carbohydrate composition of these polysaccharides rapidly and accurately in one assay without the need for derivatization.     

Quantitation of lyso-platelet activating factor molecular species from human neutrophils by mass spectrometry

Two physicochemical methods have been developed for the quantitative analysis of lyso-platelet activating factor (lyso-PAF) based on gas-liquid chromatography-mass spectrometry (GLC/MS) and fast atom bombardment-mass spectrometry (FAB/MS) using stable isotope dilution. After addition of deuterated internal standards, lyso-PAF produced from neutrophils was purified by silicic acid chromatography and thin-layer chromatography (TLC). The GLC/MS assay employed phospholipase C or hydrofluoric acid for hydrolysis of the phosphocholine moiety to yield ether monoglycerides. Condensation of monoglycerides with acetone yielded the 1-O-alkyl-2,3-isopropylidene glycerol which could be analyzed by GLC/MS. The ions corresponding to M-15 fragments for both the labeled and unlabeled derivatives were monitored in a selected ion recording mode. Standard curves were found to be linear over the range tested (10-2000 ng) with a limit of detection found to be below 200 pg injected on column. For the FAB/MS assay, the unmodified lyso-PAF was well suited for direct analysis; however, the limit of detection (S/N greater than 3) using a glycerol matrix was found to be 5 ng placed on the probe tip. It was found that human neutrophils contain approximately 300 pg/10(6) cells which increased 2-3-fold during the 5-min period following challenge with 1.9 microM calcium ionophore, A23187. Two molecular species of lyso-PAF were identified as hexadecyl and octadecyl ethers at sn-1 with the octadecyl molecular species of lyso-PAF predominating in abundance after stimulation.     

Glycinebetaine content of halophytes: Improved analysis by liquid chromatography and interpretations of results

The glycinebetaine content of plants can be determined by simple isocratic high performance liquid chromatography. The method is applicable to extracts from a wide range of species and, in most cases, is suitably rapid and specific to be preferable to other methods of analysis. The chromatographic system employed permits accurate and sensitive ultraviolet detection, free of most interferences. Because the principle plant carbohydrates elute well before glycine betaine, preparative ion exchange procedures can be simplified. Twenty-seven species, mostly inland halophytes, were screened by these methods and 13 were found to be glycinebetaine accumulators. On a dry weight basis, the glycinebetaine content of Salicornia europaea L. actually declined with exposure to progressively higher levels of NaCl. When expressed as a proportion of plant organic matter, however, patterns were more typical (up to 7.7% at higher salt concentrations).     

桂北丰水梨园土壤养分与叶片营养的相关性分析

选取桂北地区有生理异常现象发生的丰水梨园,以成年结果树为研究对象,通过检测年生长周期内梨树叶片矿质营养元素、土壤养分的含量,分析不同时期梨树叶片营养元素和土壤养分含量及其动态变化规律,探讨年生长季内叶片营养与土壤养分之间的相关关系。结果表明:(1)在生长季节内,丰水梨叶片中N、P、K含量丰富;营养元素含量随时间的变化幅度均为P最大,N、K较小,但均未达到显著水平(P>0.05)。(2)梨园土壤中有机质、水解性N含量丰富,有效P、速效K含量普遍偏高;年生长周期内土壤速效N、P、K含量随时间的推移变化较大,均达显著水平(P<0.05),而有机质含量则相对稳定。(3)梨树叶片N含量与土壤有机质、水解性N、有效P、速效K含量呈显著正相关关系(P<0.05);叶片P和K含量与土壤水解性N含量分别呈显著负相关和正相关关系(P<0.05),而与土壤有机质、有效P、速效K相关关系不明显。     

Comparison of Whole-Cell Fatty Acid (MIDI) or Phospholipid Fatty Acid (PLFA) Extractants as Biomarkers to Profile Soil Microbial Communities

The whole-cell lipid extraction to profile microbial communities on soils using fatty acid (FA) biomarkers is commonly done with the two extractants associated with the phospholipid fatty acid (PLFA) or Microbial IDentification Inc. (MIDI) methods. These extractants have very different chemistry and lipid separation procedures, but often shown a similar ability to discriminate soils from various management and vegetation systems. However, the mechanism and the chemistry of the exact suite of FAs extracted by these two methods are poorly understood. Therefore, the objective was to qualitatively and quantitatively compare the MIDI and PLFA microbial profiling methods for detecting microbial community shifts due to soil type or management. Twenty-nine soil samples were collected from a wide range of soil types across Oregon and extracted FAs by each method were analyzed by gas chromatography (GC) and GC-mass spectrometry. Unlike PLFA profiles, which were highly related to microbial FAs, the overall MIDI-FA profiles were highly related to the plant-derived FAs. Plant-associated compounds were quantitatively related to particulate organic matter (POM) and qualitatively related to the standing vegetation at sampling. These FAs were negatively correlated to respiration rate normalized to POM (Resp_POM), which increased in systems under more intensive management. A strong negative correlation was found between MIDI-FA to PLFA ratios and total organic carbon (TOC). When the reagents used in MIDI procedure were tested for the limited recovery of MIDI-FAs from soil with high organic matter, the recovery of MIDI-FA microbial signatures sharply decreased with increasing ratios of soil to extractant. Hence, the MIDI method should be used with great caution for interpreting changes in FA profiles due to shifts in microbial communities.     

Sensitive assay of phospholipid glycerol in environmental samples

Measurement of very low levels of microbial biomass was achieved by determining the glycerol content of the phospholipids from environmental samples. Successive application of acid methanolysis and hydrofluoric acid hydrolysis was used to release glycerol from the phospholipids. The glycerol, once released, was acetylated and analyzed by capillary gas-luquid chromatography (GLC). The analysis was sensitive to 10^?11 moles by GLC waith flame ionization detection and GLC/mass spectrometry with selective ion monitoring. Estimation of the microbial biomass by the lipid phosphate correlated with the glycerol phosphate measured by the hydrolytic procedures. In addition, indication of the community composition was gained by analysis of the acid labile glycerol. Application of this methodology to the sparse of the ground water sediments showed agreement with other estimates of microbial biomass.     

Bacteria–algae association in batch cultures of phytoplankton from a tropical reservoir: the significance of algal carbohydrates

Summary 1. The dissolved organic matter, especially carbohydrates, released by phytoplanktonic organisms may be ecologically important, through its influence on carbon cycling and microbial diversity. Here axenic cultures of three phytoplanktonic species, Cryptomonas tetrapyrenoidosa (Cryptophyceae), Staurastrum orbiculare (Zygnematophyceae) and Thalassiosira duostra (Bacillariophyceae), were inoculated with a microbial community from the same habitat in which the algae had been isolated (a tropical reservoir). Replicate cultures were not inoculated.
2. In both axenic and co-inoculated cultures, phytoplanktonic density and extracellular carbohydrate production were monitored microscopically and by high performance liquid chromatography with a pulse amperometric detector, respectively. Bacterial population density was also monitored by epifluorescence microscope in the microbial co-inoculated cultures.
3. Both bacterial and phytoplanktonic densities increased for 11 days in all cases. The use of extracellular carbohydrates by bacteria was also showed for all phytoplanktonic species. Of the three species of phytoplankton, only T. duostra had a faster population growth in the presence of bacteria, and reached a higher biomass than in axenic culture.     

生态系统转换对土壤中碳水化合物的影响

采集贵州省茂兰喀斯特原始红楼梦 林中森林土壤和相邻农田土壤,系统分析其中碳水化合物总量和各单糖的含量。并以此来查明由森林生态系统向农业生态系统转换的过程对土壤碳水化合物的影响,结果表明：相对于森林土壤,农业土壤中碳水化合物总量明显降低。在农田土壤中六糖/五糖比值有升高的趋势,其中以M/X比值最为明显,这说明,在该转换过程中植物来源的单糖组分有所降低,微生物来源的则相对增加。