A method for fractionation of cerebrosides into classes with different fatty acid compositions

A method is described for the separation of beef brain cerebrosides into three fractions containing different classes of fatty acids: nonhydroxy (I), unsaturated nonhydroxy (II), and hydroxy fatty acid cerebrosides (III). The procedure consists of benzoylation of either crude or purified cerebrosides, followed by column chromatographic separation of benzoylated derivatives containing nonhydroxy acids from those containing hydroxy fatty acids. The benzoyl groups are removed by sodium methoxide-catalyzed transesterification; from the reaction mixtures, fractions I and III precipitate. The fraction II present in mother liquor of I was shown to contain mainly short-chain and unsaturated nonhydroxy fatty acid cerebrosides. The fatty acid composition of each fraction was obtained by gas-liquid chromatography.     

栽培与野生化血丹不同部位中两种化学成分含量分析

为探讨并分析栽培与野生化血丹植株中不同部位中两种化学成分的含量差异,该研究采用超声法提取、高效液相色谱法(HPLC)测定栽培与野生化血丹根、茎、叶、花、混合样等部位中桃叶珊瑚苷和梓醇的含量,并进行比较。结果表明:(1)桃叶珊瑚苷在栽培与野生化血丹植株内均有分布,含量均以根中最高,其在栽培与野生化血丹植株内的含量表现分别为根>叶>混合样>茎>花、根>混合样>茎>花>叶,栽培化血丹不同部位中桃叶珊瑚苷的含量均高于野生化血丹。(2)梓醇在栽培化血丹的茎中未检出,在栽培与野生化血丹其他部位均有分布,含量均以叶中最高,其在栽培与野生化血丹植株内的含量分别表现为叶>花>混合样>根、叶>混合样>茎>花>根,野生化血丹不同部位中梓醇的含量均高于栽培化血丹。(3)桃叶珊瑚苷和梓醇在栽培和野生化血丹植株不同部位中的含量均存在显著差异(P<0.05),栽培与野生同一部位间总体上无显著差异,为该濒危药用植物资源药用部位选择和合理开发利用提供实验参考。     

Genotoxic effects and chemical compositions of four creosotes.

Four creosotes used in Finland for impregnating wood were tested in the Ames Salmonella test, the SCE test and the SOS chromotest. Compounds volatile at 37 degrees C were assayed using the taped plate testing protocol. The creosotes were fractionated according to their natural boiling ranges and the fractions were tested in the Ames Salmonella assay. Chemical compositions of creosotes and fractions were determined by high resolution gas chromatography/mass spectrophotometry techniques and by reversed phase high performance liquid chromatography. Mutagenic activities were shown to reside in fractions having the highest boiling point ranges (greater than 290 degrees C). The concentrations of mutagenic polycyclic aromatic hydrocarbons in creosotes and in some of their corresponding distillation fractions, when compared with mutagenic activities, indicated synergistic or antagonistic interactions.     

Synthesis of fluorescent-labeled cerebrosides

Synthesis of fluorescently labeled cerebrosides--N-[12-(9-anthryl)-11-trans-dodecenoyl]-1 beta-O-galactosylsphingosine and its 9-(3-perylenoyl)nonanoyl analog is described. Both probes are easily inserted in phosphatidylcholine vesicles.     

Periodate oxidation of chitosans with different chemical compositions

Periodate oxidation of chitosans with different chemical compositions were investigated by determining the consumption of periodate consumed, and the amount of ammonia and formaldehyde liberated during the reaction. Oxidised chitosans were further characterised by size-exclusion chromatography with online multi-angle light scattering (SEC-MALLS) to obtain the molecular weight distributions, and by elemental analysis to obtain the N/C ratio. Chitosans became only partially oxidised by periodate, reaching degrees of oxidation around 0.5, when oxidising with excess periodate. Overconsumption of periodate is attributed to the extensive depolymerisation, which occurs concomitantly with the oxidation, thereby exposing novel reducing and non-reducing ends which consume additional periodate. Both the rate and extent of overoxidation, and the rate of depolymerisation decreased with increasing F(A). A chitosan-specific degradation mechanism is probably involved in the depolymerisation in addition to the general free-radical-mediated degradation.     

Study on the purification and chemical compositions of tea glycoprotein

In this paper, improvement in the method for purifying glycoprotein from green tea (Camellia sinensis) was described; some properties and chemical compositions of tea glycoprotein (TGP) were determined by HPGPC, FT-IR, GC–MS technologies. Compared to existing methods, a more compatible method for purifying TGP was proposed. This method was faster, simpler, more effective and easier to be extended to the industrial production than the method that used in our previous work. The molecular weight of TGP was 126,513 Da using HPGPC. GC–MS analysis of TGP showed that TGP was composed of seven kinds of monosaccharides, namely ribose, rhamnose, arabinose, xylose, mannose, glucose, galactose in molar ratios of 1.71:5.88:13.70:1.99:1.00:1.84:33.75. Eighteen amino acids were identified in TGP by amino acid analysis. The FT-IR spectrum of the TGP revealed also typical characteristics of polysaccharides, protein and uronic acid.     

Preparation and analysis of benzoylated cerebrosides

The benzoylation of cerebrosides with benzoyl chloride and with benzoic anhydride is described, and the derivatives that contained hydroxy and nonhydroxy fatty acids were isolated by high pressure liquid chromatography (HPLC). Studies on the structures of these derivatives and the products formed by mild alkaline hydrolysis are reported. Reaction of cerebrosides containing nonhydroxy fatty acids with benzoyl chloride results in amide-acylation in addition to normal O-acylation. Mild alkali treatment of the N-diacyl derivative results in the formation of N-benzoyl psychosine. Derivatization with benzoic anhydride avoids amide-acylation. These derivatives are useful for the HPLC analysis of cerebrosides.     

Simultaneous determination of psychosine and cerebrosides

A new method was developed for the simultaneous determination of psychosine and cerebrosides in tissues. Total lipids extracted from the tissues were treated with [3H]acetic anhydride in toluene-methanol. Known amounts of nonradioactive N-acetylpsychosine were added to the reaction product and then subjected to mild alkaline methanolysis. After the product was washed, it was fractionated by silica gel column chromatography and the fraction containing glycolipids was benzoylated. The benzoylated product was finally fractionated on TLC. The amounts of benzoylated derivatives of nonhydroxy- and hydroxycerebrosides and N-acetylpsychosine were determined using a scanning densitometer. The amounts of psychosine in tissues were calculated from the radioactivity in the spot of N-acetylpsychosine and the recovery of added carrier N-acetylpsychosine. This method allowed us to determine 5 to 1000 pmol of psychosine and 1 to 20 nmol of cerebrosides in peripheral nerves and other tissues of the twitcher mouse as well as transfected Schwann cells derived from the sciatic nerves.     

Sensitizing properties of bacterial fractions of different chemical compositions

The sensitizing activity of meningococcal cells and their fractions has been studied. Only protein-containing preparations have been shown to be capable of inducing delayed hypersensitivity, while polysaccharide fractions do not induce it.     

Diversity in chemical compositions of preen gland secretions of tropical birds

The chemical composition of preen gland secretions of antbirds (Thamnophilidae and Formicaridae) and phylogenetically closely related Dendrocolaptidae, Tyrannidae and Pipridae were investigated to understand the role of environment in secretion components. The secretions of Thamnophilidae consisted of long chain acids, alcohols, esters, unsaturated hydrocarbons, and isoprenoids. Formicaridae secretions contained exclusively squalene and its derivatives. In Pipridae, secretions were made up of complex long chain esters. In Dendrocolaptidae, the secretions consisted of long chain esters of both saturated and monounsaturated acids combined with mono-alcohols and those of Tyrannidae consisted of long chain esters of saturated, mono- and tri-unsaturated acids with mono- and di-ols that were less complex. Higher molecular weight saturated and unsaturated components in tropical species suggest that the volatility of the secretion components is correlated to environmental temperatures experienced by the birds. Squalene is a precursor in steroid biosynthesis, but higher amounts in Formicaridae secretions suggest that it may have some additional functions.     

蛋白核小球藻脂溶性化合物的抑菌活性及成分分析

利用纸片法对蛋白核小球藻（Chlorella pyrenoidosa Chick.）脂溶性化合物的粗脂以及经硅胶柱层析分离后的不同组分进行了抑菌实验。结果表明,蛋白核小球藻的粗脂有极强的抑菌活性,其石油醚洗脱组分占总脂的63.9％,抑菌活性最弱;乙醇洗脱级分占总脂的32.2％,抑菌活性最强;苯洗脱组分只占总脂的3.9％,对玉米大斑病菌（Helminthosporium turcicum Pass）有极强的抑制活性。各洗脱组分及粗脂对革兰氏阴性菌均我抑制活性。成分分析结果表明,石油醚洗脱组分以烷烃类化合物为主,其中1-十九烯经烃含量最高;苯洗脱组分以6,10,14-三甲基-2-十五酮、十六碳酮和2-十一烷酮这3种酮类化合物为主;而乙醇洗脱组分含有大量的脂肪酸,其中γ-亚麻酸含量最高（56.673％）。蛋白核小球藻脂溶怀化合物的抑菌活性是其各种化学成分相互综合作用的结果。     

烫漂和干制方法对蔬菜某些化学成分的影响

探讨了不同烫漂和干制方法对苋菜和荠菜中 β-胡萝卜素、抗坏血酸和叶绿素含量的影响。结果表明 ,用 93℃± 2℃的偏亚硫酸氢钾烫漂 1 min,以上化学成分保存率最高。低温干燥能最大限度地保存干制品中的 β-胡萝卜素、抗坏血酸和叶绿素     

Reptile brain cerebrosides and cerebroside sulfates

Studies have been made on the content of cerebrosides and cerebroside sulfates, as well as on their fatty acid composition in the brain of reptiles, subclass Anapsida (tortoises Emys orbicularis and Testudo horsfieldi) and subclass Lepidosauria (lizards Agama caucasica, A. sanguinolenta, Phrynocephalus mystaceus and snake Natrix tesselata). Total content of cerebrosides and cerebroside sulfates is higher in the brain of Lepidosaurians than in that of Anapsids. In the brain of tortoises, the content of cerebroside fraction with hydroxy fatty acids is significantly higher than of the fraction with normal fatty acids, which is also typical of the brain of homoiothermic mammals and birds. In the brain of Lepidosaurians, concentration of hydroxycerebrosides is considerably lower than of cerebrosides with normal fatty acids, which is similar to lower vertebrates -- amphibians and fishes. Low content of hydroxycerebrosides was found in all the Lepidosaurians investigated, irrespectively of their ecological conditions, being therefore dependent on their phylogenetic position. The composition of fatty acids, both normal and hydroxyderivates, as well as that of glycolipids from the brain of Anapsids and Lepidosaurians is essentially similar. However, some interspecific differences were noted in the pattern of fatty acids of cerebrosides and cerebroside sulfates of the brain, which concern the content of saturated and long chain fatty acids.