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运用一种植物油的系统分析方法测定蓖麻油的精细组分,这包括皂化,BF3-MeOH甲基化,GC-CIMS法测定脂肪酸碳链长度和不饱和度,AMP衍生化,GC-EIMS测定不饱和脂肪酸的双链位置,分析了蓖麻油的十一种脂肪酸组分,有五个为未知组分,并测定了其中三个组分的双链位置。 相似文献
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全光谱技术同时测定混合物中对—硝基苯酚,邻—硝基苯酚和2,4—二硝基苯酚 总被引:6,自引:1,他引:6
采用了两种全光谱技术(付立叶主组分回归和目标转换因子分析)研究混合物中对硝基苯酚、邻硝基苯 酚和2,4-二硝基苯酚的同时测定。编制了名为SPGFPGR和SPGRTTFA的两个程序进行计算。8个误差函数用 以推断因子数目,实验结果显示这两种方法是成功的。 相似文献
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本文研究了新水溶性5,10,15,20-四(4-甲氧基-3-磺酸苯基)卟啉[T(4-MOP)PS4]的反相高效液相色谱(HPLC)分离条件。采用ShimpackPREP-ODS半制备色谱柱,用含有10mmol/L四乙基碘化铵的乙腈-水(体积比25:75)为流动相,流速18mL/min,于418nm波长下检测。[T(4-MOP)PS4]与合成中生成的杂质组分完全分离。经此制备的卟啉纯度高,已成功地应用于自来水样中微量钴、锌、铜离子的HPLC测定中。 相似文献
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建立了微生物代谢中硫酸根和硫代硫酸根的毛细管电泳分析方法.在选定实验条件下,各种阴离子(S2O2-3、SO2-4、CI-、NO-3、PO3-4)在4 min内达到完全分离,其中 S2O2-3和SO2-4迁移时间的相对标准偏差小于1%,峰面积的相对标准偏差小于5%.测定了4种菌株分别在两种培养基中的S2O2-3和SO2-4浓度随培养时间的变化.结果表明,其中一菌株在SK基中对S2O2-3有明显的氧化作用. 相似文献
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本文通过化学修饰的方法改变了γ-Al_2O_3载体等电点(IEPS),并用具有不同等电点的Al_2O_3作载体,以(NH_4)_2PdCl4为活性组分前身制备了一系列Pd/Al_2O_3催化剂,在固定床微反色谱装置上考察了其对CO氧化的催化活性,用Hi—O_2滴定、紫外漫反射光谱(DRS)、透射电子显微镜(TEM)中的能量色散谱(EDXS)等方法对上述催化剂进行了表征,结果表明:Al_2O_3的等电点(IEPS)对所得催化剂中金属分散度和浓度分布都有明显影响,IEPS越高。活性组分越靠近外表面,在相同担载量下,其分散度也越高。这主要是由于载体IEPS的改变,导致了(NH_4)_2PdCl_4在γ-Al_2O_3上吸附机理的变化,并使所得催化剂对CO氧化的催化活性发生了规律性的变化。 相似文献
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热敏性高分子包裹的磁性微球的性质及表征 总被引:11,自引:0,他引:11
利用扫描电镜、红外光谱、元素分析仪、热分析及激光散射粒径分析仪等手段对合成得到的Fe3O4/P(St NIPAM)(PSN) 和PSNN 微球的形貌、结构、磁响应性和热敏特性等进行了表征,结果表明微球的粒径分布呈正态分布,共聚物微球的Tg 随NIPAM 组分的增加而升高,PSN 和PSNN 微球均具有较强的磁响应性,其流体动力学粒径随温度的升高而减小. 相似文献
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Gardner JY Brillhart DE Benjamin MM Dixon LG Mitchell LM Dimandja JM 《Journal of separation science》2011,34(2):176-185
The cellular fatty acid profiles of eight strains of Bacillus, Staphylococcus, and Enterobacteriacae (Escherichia coli and Salmonella) were analyzed by comprehensive two-dimensional gas chromatography/time-of-flight mass spectrometry. A novel template method was developed to standardize the raw two-dimensional gas chromatography retention data through the use of a chemical indexing mixture. Analyte retention coordinates were normalized in the primary dimension with respect to a series of n-alkanes (Kovats index) and in the secondary dimension with respect to a series of aromatic hydrocarbons (Lee index). Fatty acid profiles extracted from the templates were compared by multidimensional scaling and principal component analysis. Differences in the profiles of Gram-positive and Gram-negative bacteria were observed, and a series of heterogeneous mixtures comprising different fractions (containing one Gram-positive and one Gram-negative bacteria strain) were also distinguished from their homogeneous constituents. 相似文献
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《液相色谱法及相关技术杂志》2012,35(3):407-416
Abstract High-performance liquid chromatography was used to separate and identify cellular fatty acids isolated from Vibrio parahaemolyticus, a gram-negative estuarine microorganism associated with seafood-borne enteritis in man. Fatty acids were isolated from statically grown bacterial cultures, saponified, and derivatized with an ultraviolet tag. Aliquots of derivatized fatty acids were injected onto a reversed-phase column with water:acetonitrile gradient as the mobile phase and ultraviolet detection at 254 nm. The predominant fatty acids found for the V. parahaemolyticus strains studied were C12, C14, C16:1, C16, C18:1, and C18. In addition, previously unreported fatty acids C13, C17, C19, and C21 were identified. Comparison of HPLC with GLC fatty acid separations showed good agreement with the exception that HPLC was able to resolve previously unidentified fatty acid constituents. 相似文献
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Ali Abdel ’ Aziz Ali Ibrahim Mohamed Roushdy 《Applied biochemistry and biotechnology》1998,74(2):85-93
Kinetics of cell growth and protease production by four proteolytic bacterial strains, namely,Bacillus subtilis EMCC 1020,Bacillus megaterium EMCC 1057,Serratia marcescens EMCC 1247, andPseudomonas fluorescens EMCC 1221, in milk permeate, compared with other fermentation media, were studied. The pH values, lactose utilization, and
biochemical oxygen demand (BOD) reduction in milk permeate also were investigated. The four strains were able to grow in milk
permeate, and to produce considerable amounts of protease, reaching 289 (EMCC 1020), 252 (EMCC 1057), 263 (EMCC 1247), and
212 (EMCC 1221) U/mL after 30 h of fermentation. The growth and enzyme activity of the four strains were greater in milk permeate
than those in other fermentation media. The protease-producing bacteria were able to utilize lactose in milk permeate with
values ranging from 37.62 to 54.97% and to reduce the BOD of milk permeate by 50.59-63.65%. Milk permeate proved to be the
best medium for enzyme production by all organisms examined. 相似文献
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Bacillus mycoides, Bacillus pseudomycoides, Bacillus weihenstephanensis, Bacillus anthracis, Bacillus thuringiensis, and Bacillus cereus belong to the B. cereus group. The last three species are characterized by different phenotype features and pathogenicity spectrum, but it has been shown that these species are genetically closely related. The macrorestriction analysis of the genomic DNA with the NotI enzyme was used to generate polymorphism of restriction profiles for 39 food‐borne isolates (B. cereus, B. mycoides) and seven reference strains (B. mycoides, B. thuringiensis, B. weihenstephanensis, and B. cereus). The PFGE method was applied to differentiate the examined strains of the B. cereus group. On the basis of the unweighted pair group method with the arithmetic mean method and Dice coefficient, the strains were divided into five clusters (types A–E), and the most numerous group was group A (25 strains). A total of 21 distinct pulsotypes were observed. The RFLP‐PFGE analysis was successfully used for the differentiation and characterization of B. cereus and B. mycoides strains isolated from different food products. 相似文献
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Whittaker P 《Journal of AOAC International》2011,94(5):1581-1584
Capillary GC with flame ionization detection (FID) was used to determine the cellular fatty acid (CFA) profiles of six species in the new genus Cronobacter (Enterobacter sakazakii). The six different species are C. sakazakii, C. malonaticus, C. dublinensis, C. muytjensii, C. turicensis, and C. genomospecies. For GC-FID analysis, whole cell fatty acid methyl esters (FAMEs) from cells cultured on brain heart infusion (BHI) agar at 35 degrees C for 24 h were obtained by saponification, methylation, and extraction into hexane-methyl tert-butyl ether. A data set for 57 strains of Cronobacter species was prepared using fatty acid profiles from two or three replicates prepared on different days. Major fatty acids of the Cronobacter strains evaluated in this study were straight-chain C12:0, C14:0, C16:0, and unsaturated C18:1, omega7c, summed C16:1 omega7c/C16:1 omega6c, and summed C14:0 3-OH/iso-C16:1, and C17:0 omega cyclo 7-8. The CFA profiles for the Cronobacter species are similar, but there are several fatty acids-C12:0, C14:0, C16:0, C18:1 omega7c, and summed C16:1 omega7c/ C16:1 omega6c--that differ significantly among these six species. Analysis of FAMEs from Cronobacter strains grown on BHI agar by a rapid GC-FID method is a sensitive procedure for the identification of these organisms, and this analytical method provides a procedure for the differentiation of strains from closely related Cronobacter species. 相似文献
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Panagiota Diamantopoulou Seraphim Papanikolaou Eleni Katsarou Michael Komaitis George Aggelis Antonios Philippoussis 《Applied biochemistry and biotechnology》2012,167(7):1890-1906
Volvariella volvacea strains were studied in relation with their ability to produce biomass, lipids and polysaccharides. Firstly, screening of four strains (AMLR 188, 190, 191 and 192) was performed in agar cultures, where the mycelial growth rate of the strains was measured, and in static liquid cultures, where the production of biomass, the biosynthesis of total cellular lipids and the consumption of glucose were monitored. For all strains, biomass production was significant (13?C15?g?l?1) and total lipid in dry weight (%, w/w) ranged from 3 to 12?%. Afterwards, a detailed kinetic analysis of mycelial biomass, extra- and intra- cellular polysaccharides (EPS, IPS, respectively) as well as lipid production by a V. volvacea selected strain was conducted in submerged static and agitated cultures. Maximum values of 15?g?l?1 biomass, ??1.0?g?l?1 EPS and 5.5?g?l?1 IPS were recorded. Agitation did not have severe impact on biomass, EPS and IPS production, but it increased total lipid in dry weight quantities. EPS, IPS and lipid in dry weight values decreased with time. Glucose was the major cellular carbohydrate detected. Total fatty acid analysis of cellular lipids was performed for all V. volvacea strains and linoleic acid ??9,12C18:2 was predominant. Neutral lipids constituted the major fraction of cellular lipids, but their quantity decreased as fermentation proceeded. Phospholipids were the most saturated lipid fraction. 相似文献
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To identify and analyze the characteristics of the microorganisms involved in the formation of the desirable flavor of Doenjang, a total of 179 strains were isolated from ninety-four Doenjang collected from six regions in South Korea, and fourteen strains were selected through a sensory evaluation of the aroma of each culture. The enzyme activities of amylase, protease and lipase was shown in the various strains. Bacillus sp.-K3, Bacillus sp.-K4 and Bacillus amyloliquefaciens-J2 showed relatively high protease activity, at 317.1 U, 317.3 U and 319.5 U, respectively. The Bacillus sp.-K1 showed the highest lipase activity at 2453.6 U. In the case of amylase, Bacillus subtilis-H6 showed the highest activity at 4105.5 U. The results of the PCA showed that Bacillus subtilis-H2, Bacillus subtilis-H3, and Bacillus sp.-K2 were closely related to the production of 3-hydroxy-2-butanone (23.51%~43.37%), and that Bacillus subtilis-H5 and Bacillus amyloliquefaciens-J2 were significantly associated with the production of phenethyl alcohol (0.39% and 0.37%). The production of peptides was observed to vary among the Bacillus cultures such as Val-Val-Pro-Pro-Phe-Leu and Pro-Ala-Glu-Val-Leu-Asp-Ile. These peptides are precursors of related volatile flavor compounds created in Doenjang via the enzymatic or non-enzymatic route; it is expected that these strains could be used to enhance the flavor of Doenjang. 相似文献
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Michael B. Beverly Franco Basile Kent J. Voorhees Ted L. Hadfield 《Journal of the American Society for Mass Spectrometry》1999,10(8):747-758
Free fatty acid profiling of whole bacteria [Francisella tularensis, Brucella melitensis, Yersinia pestis, Bacillus anthracis (vegetative and sporulated), and Bacillus cereus] was carried out with direct probe mass spectrometry under 70-eV electron ionization (EI) and isobutane chemical ionization in both the positive (CI+) and negative modes (CI-). Electron ionization produced spectra that contained molecular ions and fragment ions from various free fatty acids. Spectra acquired with isobutane chemical ionization in the positive mode yielded molecular ions of free fatty acids as well as ions from other bacterial compounds not observed under EI conditions. Spectra obtained with negative chemical ionization did not contain as much taxonomic information as EI or CI+; however, some taxonomically significant compounds such as dipicolinic acid and poly(3-hydroxybutyrate) did produce negative ions. All ionization modes yielded spectra that could separate the bacteria by Gram-type when observed with principle components analysis (PCA). Chemical ionization in the positive ion mode produced the greatest amount of differentiation between the four genera of bacteria when the spectra where examined by PCA. 相似文献
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Nawel Jemil Noomen Hmidet Angeles Manresa Francesc Rabanal Moncef Nasri 《Journal of mass spectrometry : JMS》2019,54(1):7-18
In this work, the extraction, structural analysis, and identification as well as antimicrobial, anti‐adhesive, and antibiofilm activities of lipopeptides produced by Enterobacter cloacae C3 strain were studied. A combination of chromatographic and spectroscopic techniques offers opportunities for a better characterization of the biosurfactant structure. Thin layer chromatography (TLC) and HPLC for amino acid composition determination are used. Efficient spectroscopic techniques have been utilized for investigations on the biochemical structure of biosurfactants, such as Fourier transform infrared (FT‐IR) spectroscopy and mass spectrometry analysis. This is the first work describing the production of different isoforms belonging to kurstakin and surfactin families by E cloacae strain. Three kurstakin homologues differing by the fatty acid chain length from C10 to C12 were detected. The spectrum of lipopeptides belonging to surfactin family contains various isoforms differing by the fatty acid chain length as well as the amino acids at positions four and seven. Lipopeptide C3 extract exhibited important antibacterial activity against Gram‐positive and Gram‐negative bacteria, antifungal activity, and interesting anti‐adhesive and disruptive properties against biofilm formation by human pathogenic bacterial strains: Salmonella typhimurium, Klebsiella pneumoniae, Staphylococcus aureus, Bacillus cereus, and Candida albicans. 相似文献
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Akpa Eric Jacques Philippe Wathelet Bernard Paquot Michel Fuchs Regine Budzikiewicz Herbert Thonart Philippe 《Applied biochemistry and biotechnology》2001,91(1-9):551-561
Bacillus subtilis produces various families of lipopeptides with different homologous compounds. To produce “new molecules” with improved activities
and to select strains that produced a reduced number of homologs or isomers, we studied the effects of different media on
the nature of the synthesis of fatty acid chains for each lipopeptide family. This study focused on two B. subtilis strains cultivated in flasks. Optimized medium for lipopeptide production and Landymedium modified by replacing glutamic
acid with other α-amino acids were used. We found that the intensity of production of homologous compounds depends on the
strain and the culture medium. Analysis of these lipopeptides by high-performance liquid chromatography showed that the strain
B. subtilis NT02 yielded various homologous compounds when cultivated in Landy medium (L-Glu), but primarily one homologous product in
high relative amounts when cultivated in the optimized medium. Mass spectrometric analysis and determination of the amino
acid composition of this molecule enabled us to identify it as Bacillomycine L c15. 相似文献