文冠果油中脂肪酸成分的色—质谱法鉴定

本文采用远端（羧基端）化学修饰新技术,将脂肪酸制成其2-烃基取代-4,4-二甲基噁唑啉衍生物,用气相色谱-质谱法结合尿素包合法对中国特有植物文冠果（Xanthoceras sorbifolia Bge.)种仁油中脂肪酸进行了深入研究,鉴定了12种脂肪酸组分。其中,廿碳二烯-11,14-酸和廿四碳烯-15-酸被首次确定了双键位置,为不常见的不饱和脂肪酸,其他10种与常规分析结果相符。本文还对制备衍生物的方法进行了探讨。     

Fatty acids are precursors of alkylamines in Deinococcus radiodurans.

Deinococcus radiodurans contains novel phospholipids of which the structures of three have been previously described. These three lipids contain both fatty acids and alkylamines. Both the fatty acid and alkylamine constituents were found to be composed of a mixture of species, of which C15, C16, and C17 saturated and monounsaturated alkyl chains predominated. Alkylamines contained a relatively higher proportion of saturated species. Progression of bacterial growth through the mid-log to stationary phases was accompanied by an increase in the proportions of C15 and C17 alkyl chains in both fatty acid and alkylamine constituents. Radiolabeled palmitic acid was found to be rapidly incorporated into both fatty acid and alkylamine components of phosphatidylglyceroylalkylamine, which is the precursor of the more-complex phosphoglycolipids found in major amounts in D. radiodurans. After culturing D. radiodurans in the presence of a mixture of palmitic acids labeled with 14C and 3H in the 1 and 9,10 positions, respectively, the same 14C/3H ratio was recovered in both fatty acid and alkylamine constituents, strongly suggesting that alkylamines are derived from intact fatty acids rather than by a de novo pathway. The results identify a novel product of fatty acid metabolism which has not to date been observed in any other organism.     

Prebiotic Organic Microstructures

Micro- and sub-micrometer spheres, tubules and fiber-filament soft structures have been synthesized in our experiments conducted with 3?MeV proton irradiations of a mixture of simple inorganic constituents, CO, N(2) and H(2)O. We analysed the irradiation products, with scanning electron microscopy (SEM) and atomic force microscopy (AFM). These laboratory organic structures produced a wide variety of proteinaceous and non-proteinaceous amino acids after HCl hydrolysis. The enantiomer analysis for D,L-alanine confirmed that the amino acids were abiotically synthesized during the laboratory experiment. We discuss the presence of CO(2) and the production of H(2) during exothermic processes of serpentinization and consequently we discuss the production of hydrothermal CO in a ferromagnesian silicate mineral environment. We also discuss the low intensity of the Earth's magnetic field during the Paleoarchaean Era and consequently we conclude that excitation sources arising from cosmic radiation were much more abundant during this Era. We then show that our laboratory prebiotic microstructures might be synthesized during the Archaean Eon, as a product of the serpentinization process of the rocks and of their mineral contents.     

圆齿野鸦椿根化学成分初步研究

圆齿野鸦椿是福建省特有的药用和观赏小乔木,可与同属植物野鸦椿的根、果实等部位入药,但目前主要开展了种子、果皮、枝和叶等部位化学成分的研究,却没有关于根部化学成分的研究报道。采用系统预试法初步探索圆齿野鸦椿根的化学成分。结果表明圆齿野鸦椿根可能含有生物碱、皂苷、醌类、黄酮类、酚类、香豆素、多糖、鞣质以及甾体和三萜类等多种有效成分,为圆齿野鸦椿根的进一步开发利用奠定了试验基础。     

The anomeric mixture of some O-galactolipid derivatives is more toxic against cancer cells than either anomer alone

The anomeric mixture of a series of O-galactolipid derivatives is revealed to be more toxic against several cancer cell lines than their either single component with the pure α- or β-configuration. This interesting phenomenon has been confirmed on pairs of synthesized O-galactosyl anomers bearing length-varied alkyl chains at the lipid end. Furthermore, the most potent mixture was determined inoffensive to a normal cell line tested.     

Chiral chromatographic separation of beta-blockers

A novel amide based chiral stationary phase m-[(+)-alpha-methyl benzyl carboxamide] XAD-4 has been synthesized by covalently linking R(+)-1-phenylethylamine to chloroformoyl Amberlite XAD-4 under weak alkaline conditions. The synthesized resin has been primarily characterized by m.p., elemental analysis and FT-IR and 13C NMR spectra. beta-Blockers viz. atenolol, metoprolol, and propranolol were successfully separated into their enantiomers using a mixture of sodium acetate-acetic acid buffer (pH 4.1):acetonitrile (4:6, v/v) solution using the synthesized resin. Hydrogen bonding and pi-pi interactions are supposed to be the major analyte-chiral stationary phase interactions.     

Synthesis of dl-aleprylic acid

dl-Aleprylic acid [7-(cyclopent-2'-en-1'-yl)-heptanoic acid], a natural constituent of chaulmoogra oil with reputed antileprosy properties, has been synthesized. Electrolysis of a mixture of (cyclopent-2'-en-1'-yl)-acetic acid and methyl monoester of heptanedioic acid in methanol yielded, after saponification of the reaction products, the racemic mixture.     

On atomic force microscopy and the constitutive behavior of living cells

Atomic force microscopy (AFM) is one of many new technologies available to study the mechanical properties and mechanobiological responses of living cells. Despite the widespread usage of this technology, there has been little attempt to develop new theoretical frameworks to interpret the associated data. Rather, most analyses rely on the classical Hertz solution for the indentation of an elastic half-space within the context of linearized elasticity. In contrast, we propose a fully nonlinear, constrained mixture model for adherent cells that allows one to account separately for the contributions of the three primary structural constituents of the cytoskeleton. Moreover, we extend a prior solution for a small indentation superimposed on a finite equibiaxial extension by incorporating in this mixture model for the special case of an initially random distribution of constituents (actin, intermediate filaments, and microtubules). We submit that this theoretical framework will allow an improved interpretation of indentation force-depth data from a sub-class of atomic force microscopy tests and will serve as an important analytical check for future finite element models. The latter will be necessary to exploit further the capabilities of both atomic force microscopy and nonlinear mixture theories for cell behavior.     

Synthesis of (±)-Hydroxytremetone

(±)Hydroxytremetone (III) has been synthesized from 2-(α-hydoxyisopropyl)-6-hydroxycoumaran (V b) via its O-acetate V c by dehydration with phosphorus tribromide in pyridine solution, followed by acylation with a mixture of trifluoroacetic anhydride and acetic acid. Isohydroxytremetone (IX b) was also synthesized.     

E. coli Ada regulatory protein repairs the SP diastereoisomer of alkylated DNA

Using HPLC and 31P NMR spectroscopy on a chemically synthesized asymmetric mixture of the diastereoisomers of thymidyl(3'----5')thymidyl-O-methyl phosphate absolute configuration has been correlated with chromatographic mobility. The methyl phosphotriester system in alkylated DNA which is repaired by the Ada regulatory protein of E. coli has consequently been established to possess the Sp configuration.     

Stereoselective synthesis of 5-O-carbamoylpolyoxamic acid (2-amino-5-O-carbamoyl-2-deoxy-l-xylonic acid

One of the constituents of polyoxin J, 2-amino-5-O-carbamoyl-2-deoxy-l-xylonic acid (3), has been synthesized stereoselectively from l-sorbopyranose. The amino acid function of 3 was formed in the final stage of the synthesis by reduction of the corresponding α-azido carboxylic acid.     

Chemical composition and behavioral responses of the marine insect Halobates hawaiiensis (Heteroptera: Gerridae)

Halobates is the only insect genus with representatives in the open ocean. How adults find one another at sea has long been an intriguing issue. Since chemical communications have been demonstrated in a related marine veliid Trochopus, and laboratory bioassays indicated behavioral differences between males and females when insect extracts were presented, we carried out similar studies on Halobates. Analyses of surface lipid constituents of female and male Halobates hawaiiensis revealed marked differences. Palmitic and oleic acid, major constituents in the male extracts, were absent in the female extract, whereas nonacosenol, dominating the female extracts, was not detected in the male extracts. Analyses of nymphal extracts indicated an intermediate chemical profile. Surface waxes of all insect stages investigated showed nonacosanol and isononacosanol to be main components. "Headspace" analyses of airborne chemicals showed high levels of 4-hydroxy-4-methyl-2-pentanone and benzaldehyde from the male, whereas benzyl alcohol was the main component in the female mixture.     

Araldite as an Embedding Medium for Electron Microscopy

Epoxy resins are suitable media for embedding for electron microscopy, as they set uniformly with virtually no shrinkage. A mixture of araldite epoxy resins has been developed which is soluble in ethanol, and which yields a block of the required hardness for thin sectioning. The critical modifications to the conventional mixtures are the choice of a plasticized resin in conjunction with an aliphatic anhydride as the hardener. The hardness of the final block can be varied by incorporating additional plasticizer, and the rate of setting can be controlled by the use of an amine accelerator. The properties of the araldite mixture can be varied quite widely by adjusting the proportions of the various constituents. The procedure for embedding biological specimens is similar to that employed with methacrylates, although longer soaking times are recommended to ensure the complete penetration of the more viscous epoxy resin. An improvement in the preservation of the fine structure of a variety of specimens has already been reported, and a typical electron microgram illustrates the present paper.     

Distinct biological effects of golgicide a derivatives on larval and adult mosquitoes

A collection of Golgicide A (GCA) analogs has been synthesized and evaluated in larval and adult mosquito assays. Commercially available GCA is a mixture of four compounds. One enantiomer (GCA-2) of the major diastereomer in this mixture was shown to be responsible for the unique activity of GCA. Structure-activity studies (SAR) of the GCA architecture suggested that the pyridine ring was most easily manipulated without loss or gain in new activity. Eighteen GCA analogs were synthesized of which five displayed distinct behavior between larval and adult mosquitos, resulting in complete mortality of both Aedes aegypti and Anopheles stephensi larvae. Two analogs from the collection were shown to be distinct from the rest in displaying high selectivity and efficiency in killing An. stephensi larvae.     

驼绒藜中两个新的咖啡酯及其它化合物

对采自宁夏沙坡头的藜科驼绒藜进行化学成分研究,从中分离得到20个化合物,其中一个为咖啡酯的混合物(其中咖啡酸十九酯和咖啡酸十五酯为新的咖啡酯),一个苯甲酸衍生物,5个已知植物蜕皮激素,10个甾体化合物,3个肉桂酸及其衍生物。它们的结构经光谱分析(IR,MS,NMR)结合一定的化学方法、物理常数被确定。这些化合物都是第一次从该属植物中分离得到。     

Prediction models for the pleasantness of binary mixtures in olfaction

Whereas the rules underlying the perceived intensity of binary mixtures have been investigated, minimal efforts have been directed at elucidating the rules underlying the perceived pleasantness of such mixtures. To address this, 84 subjects ranked the pleasantness and intensity of 5 distinct binary mixtures (15 pairs, inter-stimulus interval = 4 s, inter-trial interval = 30 s, flow = 6 l/min, pulse = 2 s) constructed from different ratios (0:100%, 25:75%, 50:50%, 75:25%, and 100:0%, olfactometer-generated vapor phase). We found that in the majority of cases, the pleasantness of the mixture fell between the pleasantness values of its separated constituents and that it was strongly influenced by the relative intensities of the constituents. Based on these results, we proposed a prediction paradigm for the pleasantness of binary mixtures from the pleasantness of their separated constituents weighted by their respective perceived intensities. The uniqueness of the proposed paradigm is that it neither requires presetting an interaction constant between the mixture components nor require any factorization of the pleasantness weights. It does, nonetheless, require solid psychophysical data on the separated components at their different concentrations, and currently it can only explain the behavior of intermediate pleasantness of mixtures.     

Synthesis of visual rhodopsin in a cell-free translation system. I. Influence of the structure of the synthetic bovine visual opsin mRNA on its translational efficiency

Influence of structural changes in nontranslated regions and translation initiation site of the in vitro synthesized bovine opsin mRNA on its translational efficiency in the wheat germ cell-free system has been studied. It is shown that level of the opsin synthesis up to 30 micrograms per 1 ml of translational mixture can be attained by optimizing structure of 5'-nontranslated region.     

Identification of 16-hydroxyoxohexadecanoic acid monomers in plant cutins

The structure of a new hydroxyketo fatty acid which occurs as a major monomer of Citrus limon fruit cutin has been determined by IR, NMR and MS. The monomer was shown to be a mixture of positional isomers of 16-hydroxyoxohexadecanoic acid with the 10-oxo isomer predominating. Substantial amounts of the 9-oxo isomer were present together with smaller quantities of the 8- and 7-isomers. The same compounds were also found to be important constituents of the fruit cutins of Physalis peruviana and Ribes nigrum.     

Metabolism of Pyridine Coenzymes in Microorganisms

NADP was enzymatically synthesized from NAD and p-nitrophenyl phosphate or nucleoside monophosphate with the enzyme preparation of Proteus mirabilis (IFO 3849). In this phosphotransferring reaction, ATP did not serve as phosphoryl donor.

In addition to NADP, an unidentified substance (Compound I) showing fluorescence with methyl ethyl ketone and having no coenzyme activity to glutamic dehydrogenase was synthesized. The yield of NADP was usually below 30 per cent of Compound I.

NADP was isolated from the reaction mixture and its coenzyme activity to some dehydrogenases was demonstrated.

A new derivative of NAD (Compound I) synthesized from NAD and p-nitrophenyl phosphate by the enzyme preparation of Proteus mirabilis (IFO 3849), was isolated from the reaction mixture.

After degradation of this compound with snake venom nucleotide pyrophosphatase, Compound III was obtained. 5′-NMN was phosphorylated to Compound IV by the same enzyme preparation of P. mirabilis. By the determination of chemical constituents and the degradation with phosphomonoesterases, Compounds III and IV were identified as nicotinamide riboside 2′(3′),5′-diphosphate, and Compound I was identified as NADP analog which was formed by phosphorylation at the 2′ or 3′ position of the nicotinamide ribose moiety, not at the 2′ position of adenosine moiety of NAD.     

The influence of oligodeoxyribonucleotide phosphorothioate pyrimidine strands on triplex stability.

The analogues of the homopyrimidine oligonucleotide dT15 has been synthesized. The analogues, contains phosphorothioate bonds of a mixture of diastereoisomers or one of the two stereoisomer (either Rp or Sp). The analogues were mixed under conditions conductive to the formation of triple stranded assemblies. The mixtures were characterized by their thermal stabilities (Tm values) and CD spectra.