Development of a Defined Medium for Arachidonic Acid Production by Mortierella alpina Using a Visualization Method

Defined medium for arachidonic acid (ARA) production by Mortierella alpina was optimized for its metabolomics study. For this purpose, a visualization method (VM) was applied for the first time. Experiments were designed according to the uniform design with four factors (concentrations of glucose, NaNO₃, KH₂PO₄ and MgSO₄·7H₂O) for each at nine levels. Dry cell weight (DCW), ARA yield in DCW [percent (w/w)] and ARA content in total fatty acids [percent (w/w)] were considered as the three objectives. Optimization of single-objective function and multi-objective function of two objectives and three objectives was attempted. Optimal DCW, ARA yield and ARA content were predicted to occur in a medium that contained (grams per litre): glucose 35, NaNO₃ 1, KH₂PO₄ 7.5 and MgSO₄·7H₂O 2.6. Upon verification, the average tested DCW (12.95?g/l), ARA yield (18.89?%) and ARA content (42.36?%) were fairly close to the predicted values (12.88?g/l, 9.68?% and 35.57?%, respectively). Moreover, DCW, ARA yield and ARA content from the optimum medium increased by 35.68, 47.23 and 30.90?% compared with control, respectively, indicating that VM had succeeded in exploiting the biomass growth and ARA production by M. alpina.     

Liquid Chromatographic Separation of Some Common Benzodiazepines and their Metabolites

Abstract

A series of benzodiazepines commonly encountered in forensic samples were separated using isocratic reversed-phase liquid chromatography. These compounds display a wide range of capacity factors on a C₁₈ stationary phase in a pH 8 phosphate buffer and methanol mobile phase. Clorazepate must be analyzed under basic mobile phase conditions to prevent its decomposition to N-desmethyldiazepam. The separation of common parent benzodiazepines such as chlordiazepoxide, diazepam and flurazepam from their corresponding metabolites was achieved under a variety of reversed-phase conditions.     

Separation of Twelve Catecholamine Metabolites and Determination of Some of the Metabolites in Human Urine by Liquid Chromatography with Electrochemical Detection

Abstract

Separation of twelve catecholamine metabolites on a reversed-phase column was achieved, when eluate from the column was amperometrically monitored at +800 mV vs. Ag/AgCl. The mobile phase was a 0.1 M acetate buffer (pH 5.0). The flow rate and column temperature were 1.5 ml/min and 25 ± 1°C, respectively. Ethyl acetate extraction of the catecholamine metabolites from acidified human urine was studied and optimized. We demonstrate the feasibility of the method showing some liquid chromatographic results.     

Quantum Yields of Singlet-Oxygen Production by Some Natural Quinoid Fungal Metabolites and Derivatives

Perylene quinone compounds of natural and syntheitc origin have been investigated for their quantum efficiency of singlet-oxygen production (Φ_Δ). The results may be interpreted by a qualitative relation between Φ_Δ and the planarity of the sensitizer molecules, highest values (0.8–0.9) being observed where planarity is favoring tautomeric structures. On the other hand, derivatives exhibiting non-planar quinoid structures show lower Φ_Δ, and methylated derivatives react photochemically.     

Comparison of Some Secondary Metabolites in Cotton Leaves That Differ in Genetic Markers

The change in the content of sterols, tocopherols, and polyprenols during three phases of cotton ontogenesis that differ in genetic markers was studied. The content of these components of self-marking strains and their parental varieties is compared     

Investigation on Oxidation-Reduction Properties of Some Fe-S and Mo-Fe-S Clusters

Oxidation-reduction properties of some Fe-S and Mo-Fe-S clusters have been studied by cyclic voltammetric measurement. It is indicated that there are some factors which affect the oxidation- reduction properties of clusters, of which are charge density of metal atom in cluster core, electron effect of ligands, charge and geometric configurations of the reactant particle, etc.     

气相色谱化学电离二级质谱法对玉米籽粒中三嗪类除草剂及其代谢物的测定

建立了玉米籽粒中三嗪类除草剂及其代谢物残留的气相色谱化学电离二级质谱(GC-CI MS/MS)分析方法.样品采用盐酸和乙腈混合溶液均质提取,石墨化碳黑(GCB)与中性氧化铝的混合固相萃取柱净化,GC-CI MS/MS基质外标法测定.三嗪类除草剂及代谢物在0.05(0.10) ～4.0 mg/L范围内线性良好,相关系数r在0.993 9以上(脱乙基莠去津溶剂标准曲线的r=0.989 4);在0.050、0.100 μg/g添加水平,平均添加回收率为72% ～108%,相对标准偏差为3.09% ～20.14%,满足进出口及残留监控测定的需要.     

High-Pressure Liquid Chromatographic Separation of Diphenhydramine and Some of its Metabolites: Effects of Eluent Salt Concentration on Chromatographic Characteristics

Abstract

With appropriate variation of the pH, alkali halogenide concentration and cation and/or anion species in the mobile phase (mixtures of water and methanol), it was possible to resolve diphenhydramine, N-desmethyldiphenhydramine, N,N-didesmethyldiphenhydramine, benzhydrol, benzophenone and 2-methyldiphenylmethoxy acetic acid on a reversed-phase column. The retention volumes of the three amines decreased by increasing the following parameters: salt concentration, methanol concentration and cation and/or anion size. The retention volumes of the other compounds were not influenced. The good separation and the simplicity make this method attractive for use in metabolism studies.     

Metabolites of fusidium coccineum

Nine cometabolites of the antibiotic fusidic acid (1a) have been identified. These include the fusidane derivatives (5a, 6a, 7a, 8a, 9a, 10a, and 12a), 7,8-dehydropseudofusidic acid (11a), and fusilactidic acid (13a).     

Investigation of Phosphorylation of Cyclodextrins and Some their Derivatives

Abstract

Principal regularities of per- and regodirected phosphorylation of α-β-, and γ-cyclodextrins (R=R¹=R²=OH, n= 1–3) by trivalent phosphorus reagents were investigated. As a result, the first representatives of regularly organized phosphites and amidophosphites of cyclodextrins, including ones with interglucoside 2,3′-cyclophosphite bridges [R¹+R²=-P(NR₂′)-], having chiral cavities of different sizes, were obtained. Per-6-deoxy-6-bromocyclodextrins (R=Br) were considered as convenient intermediates for the synthesis of pyndinium salts with amphiphilic properties for the enhanced water-solubility and for the definite orientation at the phase boundary organic liqiud-water.     

被孢霉菌丝体脂肪酸组成的气相色谱-质谱分析

采用气相色谱－质谱对采自云南白马雪山土壤中并经分离和发酵培养的被孢霉菌株SM96的菌丝体油脂中脂肪酸组成进行了定性分析和峰面积相对含量测定,共检测出30种脂肪酸,其中多不饱和脂肪酸含量为62．4％,主要为亚油酸、α－亚麻酸（ALA）,还有少量的γ－亚麻酸、二十碳三烯酸、花生四烯酸和二十碳五烯酸（EPA）等,结果表明该菌株能产生EPA。     

Metabolites of microorganisms. Aranciamycin

Aranciamycin is a new antibiotic isolated from cultures of a strain of Streptomyces echinatus. The orange-yellow acidic compound, C₂₇H₂₈O₁₂, is a glycoside of an aglycone, aranciamycinone, and a 6-deoxyhexose monomethyl ether. The aglycone, C₂₀H₁₆O₈, is composed of a 1, 8-dihydroxyanthraquinone nucleus, to which a fourth carbocyclic six-membered ring is condensed, bearing a tertiary C-methyl group, a tertiary and a secondary hydroxyl group, a secondary methoxyl group, and a carbonyl group. A partial formula of the aglycone is given. Aranciamycin as well as its aglycone are strongly inhibitory against gram-positive bacteria on synthetic media. The antibiotic activity is considerably decreased by the addition of amino-acid combinations and pyruvate to the test medium.     

Secondary Metabolites of Clinacanthus nutans

Chemistry of Natural Compounds -     

Secondary Metabolites of Mahonia bealei

Chemistry of Natural Compounds -     

Secondary Metabolites of Elaeagnus thunbergii

Chemistry of Natural Compounds -     

Secondary Metabolites of Litchi chinensis

Chemistry of Natural Compounds -     

Effects of External Enzymes on the Fermentation of Soybean Hulls to Generate Lipids by Mortierella isabellina

Hydrolytic enzymes were evaluated on the lipid accumulation via an oleaginous fungal species, Mortierella isabellina, cultivated on sugars released from soybean hulls. The weight loss of soybean hull, fungal growth, and lipid production were tested under different loads of hydrolytic enzymes. M. isabellina could not directly utilize cellulose and adding cellulase and ??-glucosidase significantly increased the cell growth and oil accumulation of M. isabellina on soybean hulls. The highest weight loss of soybean hulls was 47.80?% and the lipid production reached 0.14?g from 1?g of soybean hull when 12?U cellulase, 27.2?U ??-glucosidase, 2,278.56?U pectinase, and 15?U hemicellulase were added. Fatty acids (76.82?%) accumulated in M. isabellina were C16 and C18, which are suitable for biodiesel production. These results provide a new application for soybean hulls to be applied as the raw material for the production of biodiesel fuel, besides its traditional role as animal feed supplements.     

Investigation of Electrochemical Behavior of Some Dithiophosphonates in Acetonitrile on the Platinum and Gold Electrodes

Some dithiophosphonate derivatives were synthesized and the electrochemical reduction mechanism was investigated by cyclic voltammetry (CV), square wave voltammetry (SWV) and chronoamperometry (CA) in 0.1 M tetrabutylammoniumtetrafluoroborate (TBATFB) in acetonitrile at platinum (Pt) and gold (Au) electrodes. Dithiophosphonates showed a cyclic voltammetric reduction peak at about ?1.1 V at Pt and ?1.3 V at Au electrode (vs. Ag/Ag⁺) in this media. It was also shown that dithiophosphonates can be determined quantitatively in acetonitrile using a calibration graph. The number of electrons transferred were calculated as 2 using ferrocene as a reference compound at the UME electrode. Mechanism of dithiophosphonates was also examined on Pt and Au electrodes and electrochemical reduction of dithiophosphonates seems to follow an EC mechanism with an irreversible electron transfer step. The reaction product in the bulk electrolysis experiment was isolated and identified using proton‐coupled P‐31 NMR, ¹³C‐NMR and IR spectroscopy. The adsorption tests for dithiophosphonates were revealed that no strong or weak adsorption phenomena exist on both Pt and Au electrodes. Simulation curves were acquired by DigiSim 3.03 version to investigate the reduction mechanism and to estimate the kinetic parameters for electrochemical and chemical steps.