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1.
Summary. For-Met-βAlaψ[CSNH]-Phe-OMe (3), For-Met-βAlaψ[CH2NH]-Phe-OMe (5), For-Met-NH-pC6H4-SO2-Phe-OMe (8a), For-Met-NH-mC6H4-SO2-Phe-OMe (8b) and the corresponding N-Boc precursors (2, 4, 7a, b) have been synthesized and their activity towards human neutrophils has been evaluated in comparison with that shown by the reference tripeptide For-Met-Leu-Phe-OMe (fMLF-OMe). Chemotaxis, lysozyme release and superoxide anion production have been measured. 1H NMR titration experiments and IR spectra have been discussed in order to ascertain the preferred solution conformation adopted by the tripeptide 3 with particular reference to the presence of a folded conformation centred at the centrally positioned thionated β-residue.  相似文献   

2.
The preparation of boronated triaryl and tetraaryl phosphonium salts of the type [PPh3CH2R]Br [R is 4-boronophenyl (1), 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-yl)phenyl (2), 3-boronophenyl (3), 3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-yl)phenyl (4), 2-boronophenyl (5), 2-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-yl)phenyl (6), and closo-1,2-carboran-1-yl (7)] is described. These compounds were prepared by the reaction of triphenylphosphine with benzylic bromides or 1-bromomethyl-closo-1,2-carborane in acetonitrile solution at 85 °C. The zwitterionic nido-7,8-carborane derivative PPh3CH2C2B9H11 (8) was prepared by treatment of 7 with cesium fluoride in refluxing ethanol. All compounds were fully characterized by multinuclear (1H, 11B, 13C, and 31P) 1D- and 2D-NMR spectroscopy, electrospray ionization mass spectrometry, and elemental analysis, and single-crystal X-ray structures were determined for compounds 1, 3, 7, and 8. The cytotoxicities and boron uptake of selected derivatives were investigated in vitro using human glioblastoma (T98G) and canine kidney tubule (MDCK II) cells. The zwitterionic species 8 was found to be the least cytotoxic agent while also delivering the greatest amount of boron to the T98G cells, peaking at 9.15 ± 2.65 μg B/mg protein.  相似文献   

3.
A homologous series of eleven δ-lactones (1,5-alkanolides) was identified in cuticular waxes from leaves of Cerinthe minor L., six of them representing novel compounds. They accounted for 79% of the total coverage of 41 μg wax per cm2 leaf area. Various chemical transformations with product identification by GC-mass spectrometry and GC-FTIR were employed to assign the structures. The chain-lengths of the δ-lactones ranged from C22 to C32 and even-numbered homologues were prevalent. Additionally, aldehydes (C26–C30), alkanes (C23–C29), primary alcohols (C26–C32), alkanoic acids (C20–C32), wax esters (C40–C56) and lupeol were detected.  相似文献   

4.
M. Riederer  G. Schneider 《Planta》1990,180(2):147-153
The constituents of the soluble cuticular lipids (SCL) of the leaf blades of Citrus aurantium L. were identified by gas chromatography-mass spectrometry and quantified. Major components were 1-alkanols (C24 to C40), n-alkyl esters (C36 to C56), n-alkanoic acids (C28 to C34), n-alkanes (C22 to C40) and triterpenones, while n-alkanals (C29 to C38), sterols, and alkyl benzenes (molecular weights 260, 274 and 288) made minor contributions. Leaf age and side significantly affected the quantitative composition of SCL. Increased day temperature during the development of leaves led to decreased amounts per unit area of n-alkanes, 1-alkanols, n-alkanoic acids and n-alkyl esters while increased night temperatures resulted in increased amounts of n-alkanes n-alkanoic acids and 1-alkanols. Relative humidity had no effect on the amounts or composition of SCL. The permeability of cuticular membranes to water (described in part I of this paper) and the composition of SCL were not related. A model for the molecular structure of the transport-limiting barrier of plant cuticles and for the transport of water across it is proposed.Abbreviations CM cuticular membrane - GC gas chromatogra-phy - MS mass spectroscopy - TLC thin-layer (planar) chromatography - SCL soluble cuticular lipids The authors are indebted to Dr. R. Winkler and H. Krause, Laboratorium für Strukturchemie des Fachbereichs Chemie, Biologie und Geowissenschaften, Technische Universität München, FRG, for performing the GC-MS analyses and their valuable help in the identification of SCL constituents. This work has been supported by the Deutsche Forschungsgemeinschaft and the Bayerische Staatsministerium für Wissenschaft und Kunst.  相似文献   

5.
Suberin from the roots of carrots (Daucus carota), parsnip (Pastinaca sativa), rutabaga (Brassica napobrassica), turnip (Brassica rapa), red beet (Beta vulgaris), and sweet potato (Ipomoea batatas) was isolated by a combination of chemical and enzymatic techniques. Finely powdered suberin was depolymerized with 14% BF3 in methanol, and soluble monomers (20-50% of suberin) were fractionated into phenolic (<10%) and aliphatic (13-35%) fractions. The aliphatic fractions consisted mainly of ω-hydroxyacids (29-43%), dicarboxylic acids (16-27%), fatty acids (4-18%), and fatty alcohols (3-6%). Each fraction was subjected to combined gas-liquid chromatography and mass spectrometry. Among the fatty acids very long chain acids (>C20) were the dominant components in all six plants. In the alcohol fraction C18, C20, C22, and C24 saturated primary alcohols were the major components. C16 and C18 dicarboxylic acids were the major dicarboxylic acids of the suberin of all six plants and in all cases octadec-9-ene-1, 18-dioic acid was the major component except in rutabaga where hexadecane-1, 16-dioic acid was the major dicarboxylic acid. The composition of the ω-hydroxyacid fraction was quite similar to that of the dicarboxylic acids; 18-hydroxy-octadec-9-enoic acid was the major component in all plants except rutabaga, where equal quantities of 16-hydroxyhexadecanoic acid and 18-hydroxyoctadec-9-enoic acid (42% each) were found. Compounds which would be derived from 18-hydroxyoctadec-9-enoic acid and octadec-9-ene-1, 18-dioic acid by epoxidation, and epoxidation followed by hydration of the epoxide, were also detected in most of the suberin samples. The monomer composition of the six plants showed general similarities but quite clear taxonomic differences.  相似文献   

6.
The complex of pesticidal metabolites produced byStreptomyces griseus LKS-1 consists of a peptide antibiotic (A), nonactic acids (B), macrotetrolides (C), pyrrolizines (D), and of cycloheximide. The latter unwanted phytotoxic compound was eliminated by treatment with mutagens. Combined approaches, including both genetic and physiological manipulations, resulted in the following alterations in the biosynthetic capacity: (1) A more than 80-fold increase in the production of C under a substantial decrease in the yields ofA, B andD, the ratio of the components ofC being steered toward the required more active ones; (2) a more than 300-fold increase in the production ofB under suppression of the formation ofA andC: (3) a 10-fold increase in the yields ofD under suppression ofA andC; (4 a significant increase in the yields ofA with eliminatingB, C andD. The level of inorganic phosphate in fermentation media and the sensitivity of the organism to carbon catabolite repression were important factors participating in the regulation of the above biosynthetic processes.  相似文献   

7.
Abstract The changes of fatty acids in larvae of the wheat blossom midge, Sitodiplosis mosellana (Gehin) at different periods were examined by gas choromatography. There were 10–16 kinds of fatty acids, of which the predominant ingredients were palmitic (C16:0), oleic (C18:1) and linoleic (C18:2) acids which were more than 95% in total fatty acids, stearic acid (C18:0) about 2%‐3.5% and any of the others was less than 1%. The fatty acid compositions increased from mid‐May, when larvae of the wheat blossom midge left the wheat‐ears and fallen on the ground, to April of next year before pupating and emerging. No arachidic acid (C20.0) was discovered in over‐summering, over‐wintering as well as inactive over‐wintered larvae. The content of saturated fatty acids in over‐summering, overwintering as well as inactive over‐wintered larvae were less than those of in active over‐wintered larvae and wheat‐ear larvae. Therefore, changes of the arachidic acid and the proportions of saturated fatty acids/unsaturated fatty acids could be used as one of the biochemical criteria to determine the active state and the degree of diapause in larvae of the wheat blossom midge.  相似文献   

8.
A new lipoxygenase inhibitor, 6'-hydroxyoxosorbicillinol (1, C14H16O6), was identified from a culture of Penicillium sp. A known compound, oxosorbicillinol (2, C14H16O5), was also isolated. Compound 1 showed an approximately 10 times greater inhibitory effect on soybean lipoxygenase (IC50, 16 µM) than 2 (IC50, 150 µM), and also showed prostaglandin D2 (PGD2) and leucotriene B4 (LTB4) release suppression activity (IC50, 10 µM for PGD2 and 100 µM for LTB4).  相似文献   

9.
The effects of fatty acids, extracted during prefermentation grape skin-contact on Saccharomyces cerevisiae and Oenococcus oeni, were studied. The influence of skin-contact on total fatty acid content was evaluated both in Chardonnay must and in synthetic medium. Prior to alcoholic fermentation, the skin-contact contributes to a large enrichment of long-chain fatty acids (C16 to C18:3). These results induced a positive effect on yeast growth and particularly on cell viability. In the skin-contact fermented media, levels of C12 and especially C10 are lower and macromolecules content higher than in controls. This production of extracellular mannoproteins and the reduction of medium-chain fatty acids in media by S. cerevisiae increased growth of O. oeni. The influence of fatty acids (C10 to C18:3), in their free and esterified forms, on bacterial growth and on malolactic activity was also examined. Only C10 and C12, especially in their esterified forms, always appeared to be toxic to O. oeni. Received 15 May 1997/ Accepted in revised form 02 December 1997  相似文献   

10.
ABSTRACT

Pressure dependence of stability, phonon, Debye temperature, physical, mechanical and thermodynamic properties of Rh3Al intermetallic compound were investigated by first-principles The calculated cohesive energy (Ec), formation enthalpy (ΔH) show that Rh3Al is a thermodynamically stable compound. Properties related to the phonons of Rh3Al were also obtained. In addition, the transverse sound velocity (νs), longitudinal sound velocity (νl), average sound velocity (νm) and Debye temperature (ΘD) of Rh3Al were calculated by using the VRH method along with pressure range from 0 to 60?GPa. The values of lattice parameters, bulk modulus and its first-order pressure derivative are consistent well with other works. The band structure indicates that Rh3Al compound exhibits a metallic character. Moreover, the total density of states, partial density of states, Mulliken charges and electron density difference have been analysed to explain the physical properties. Based on the stress–strain approach and the Born stability criteria, the mechanical properties were evaluated by elastic constants (Cij), other modulus (B, E, G), (B/G) ratio, Poisson’s ratio (ν), the anisotropic index (A), hardness (H) and compressibility (K) for this intermetallic compound. Finally, the thermodynamic properties, including enthalpy, free energy, entropy and heat capacity are discussed range from 0 to 1000?K.  相似文献   

11.
n-Decyl (C10), undecyl (C11), lauryl (C12) and myristyl (C14) alcohols induced nutritional encephalomalacia, when fed to one-day-old White Leghorn male chicks for 3 weeks, while n-heptyl (C7), n-octyl (C8), n-nonyl (C9), cetyl (C16) and stearyl (C18) alcohols did not. Esters of the former group, i.e. n-decyl acetate, lauryl stearate and dilauryl succinate, and aldehydes corresponding to the former group, i.e. n-decyl aldehyde and lauraldehyde, also had the ability to induce encephalomalacia. The disease can be completely prevented by dietary supplementation of dl-β-tocopheryl acetate. Median lethal dietary level of n-decyl and lauryl alcohols and lauraldehyde was estimated to be 20, 18, and 12% respectively.  相似文献   

12.
Qualitative and quantitative compositions of esterified fatty acids (FAs) in the total lipids from the leaves, shoots, and roots of halophile plants, such as suaeda (Suaeda altissima), samphire (Salicornia europaea), and wormwood (Artemisia lerchiana), collected in their natural environments were estimated by GLC techniques. It was shown that the vegetative organs of these halophytes contained 24 FA species, and 16 of them were tentatively identified as the very-long-chain FAs (VLCFAs). There were four VLCFA groups, viz. C20, C21, C22, and C23, each including saturated, mono-, and diunsaturated components; C24 and C25 FAs were also present. The concentration of VLCFAs in the total FAs comprised 4–64%. In vegetative organs of higher plants not subjected to genetic transformation, such a high VLCFA content was found for the first time. Saturated and even-numbered components predominated among the VLCFAs, and the roots exceeded severalfold the above-ground organs in the total VLCFA content. Possible pathways of VLCFA biosynthesis in plants, VLCFA content in the vegetative tissues, and the physiological role of membrane lipid FA composition in the plant salt metabolism are discussed.  相似文献   

13.
Partial hydrolysis of triacylglycerols of high-erucic-acid seed oils from white mustard (Sinapis alba), oriental mustard (Brassica juncea) and honesty (Lunaria annua), catalysed by lipases from Candida cylindracea and Geotrichum candidum, leads to enrichment of erucic acid and other very-long-chain mono-unsaturated fatty acids (VLCMFA) in the acylglycerols (mono-, di- and triacylglycerol) while the C18 fatty acids (oleic, linoleic and linolenic) are enriched in the fatty acid fraction. Partial hydrolysis of the high-erucic-acid triacylglycerols, catalysed by lipases from porcine pancreas, Chromobacterium viscosum, Rhizopus arrhizus and Rhizomucor miehei yields fatty acids with substantially higher levels of VLCMFA, as compared to the starting material, while the C18 fatty acids are enriched in the acylglycerol fraction. Lipases from Penicillium sp. and Candida antarctica are ineffective for the fractionation of either group of fatty acids. Transesterification of the high-erucic-acid triacylglycerols with ethyl, propyl or butyl acetate or with n-butanol, catalysed by the lipase from R. miehei, leads to enrichment of VLCMFA in the alkyl (ethyl, propyl or butyl) esters, whereas the C18 fatty acids are enriched in the acetylacylglycerols and acylglycerols.  相似文献   

14.
《Insect Biochemistry》1989,19(8):767-774
The fatty acid content and composition of the house cricket Acheta domesticus have been investigated in entire insects at different developmental stages and in selected organs of male and female adults. We have also determined the fatty acid composition of the various lipid classes within extracts of the organs of adult female insects. Fatty acids were analysed by capillary gas chromatography or mass spectrometry as their methyl esters (FAMEs) after direct transesterification of insect material or separated lipid classes.The major esterified fatty acids in all extracts were palmitate (C16:0), stearate (C18:0), oleate (C18:1) and linoleate (C18:2). Levels of esterified fatty acid varied considerably between organs but the fatty acid compositions showed only small variations. The levels of polyunsaturated fatty acids of the C18 series were considerably higher in phospholipid fractions than in other lipid classes. Triacylglycerols formed the major lipid class in ovaries, fat-body and newly-laid eggs, whereas diacylglycerols and phospholipid predominate in the haemolymph. Triacylglycerols, phospholipids, diacylglycerols and free fatty acids were all found in significant amounts in the gut tissue.  相似文献   

15.
This is the first report devoted to study of the hydrocarbon composition of the extract of buds of European birch Betula pendula (family Betulacea). We have identified saturated (C16 to C28, even number of carbon atoms) and unsaturated (linoleic and linolenic) fatty acids, β-caryophyllene, α-humulene, and the components of epicuticular waxes of cover scales, such as n-alkanes (C21 to C26), esters of fatty acids (C16 to C28, even number of carbon atoms), and fatty alcohols (C18 to C30, even number of carbon atoms). The gas chromatographic retention indices of all identified compounds have been determined.  相似文献   

16.
The potential for C4 photosynthesis was investigated in five C3-C4 intermediate species, one C3 species, and one C4 species in the genus Flaveria, using 14CO2 pulse-12CO2 chase techniques and quantum-yield measurements. All five intermediate species were capable of incorporating 14CO2 into the C4 acids malate and aspartate, following an 8-s pulse. The proportion of 14C label in these C4 products ranged from 50–55% to 20–26% in the C3-C4 intermediates F. floridana Johnston and F. linearis Lag. respectively. All of the intermediate species incorporated as much, or more, 14CO2 into aspartate as into malate. Generally, about 5–15% of the initial label in these species appeared as other organic acids. There was variation in the capacity for C4 photosynthesis among the intermediate species based on the apparent rate of conversion of 14C label from the C4 cycle to the C3 cycle. In intermediate species such as F. pubescens Rydb., F. ramosissima Klatt., and F. floridana we observed a substantial decrease in label of C4-cycle products and an increase in percentage label in C3-cycle products during chase periods with 12CO2, although the rate of change was slower than in the C4 species, F. palmeri. In these C3-C4 intermediates both sucrose and fumarate were predominant products after a 20-min chase period. In the C3-C4 intermediates, F. anomala Robinson and f. linearis we observed no significant decrease in the label of C4-cycle products during a 3-min chase period and a slow turnover during a 20-min chase, indicating a lower level of functional integration between the C4 and C3 cycles in these species, relative to the other intermediates. Although F. cronquistii Powell was previously identified as a C3 species, 7–18% of the initial label was in malate+aspartate. However, only 40–50% of this label was in the C-4 position, indicating C4-acid formation as secondary products of photosynthesis in F. cronquistii. In 21% O2, the absorbed quantum yields for CO2 uptake (in mol CO2·[mol quanta]-1) averaged 0.053 in F. cronquistii (C3), 0.051 in F. trinervia (Spreng.) Mohr (C4), 0.052 in F. ramosissima (C3-C4), 0.051 in F. anomala (C3-C4), 0.050 in F. linearis (C3-C4), 0.046 in F. floridana (C3-C4), and 0.044 in F. pubescens (C3-C4). In 2% O2 an enhancement of the quantum yield was observed in all of the C3-C4 intermediate species, ranging from 21% in F. ramosissima to 43% in F. pubescens. In all intermediates the quantum yields in 2% O2 were intermediate in value to the C3 and C4 species, indicating a co-function of the C3 and C4 cycles in CO2 assimilation. The low quantum-yield values for F. pubescens and F. floridana in 21% O2 presumably reflect an ineffcient transfer of carbon from the C4 to the C3 cycle. The response of the quantum yield to four increasing O2 concentrations (2–35%) showed lower levels of O2 inhibition in the C3-C4 intermediate F. ramosissima, relative to the C3 species. This indicates that the co-function of the C3 and C4 cycles in this intermediate species leads to an increased CO2 concentration at the site of ribulose-1,5-bisphosphate carboxylase/oxygenase and a concomitant decrease in the competitive inhibition by O2.Abbreviations PEP phosphoenolpyruvate - PGA 3-phosphoglycerate - RuBP ribulose-1,5-bisphosphate  相似文献   

17.
Amadi is a small sized edible marine fish species (Coilia reynaldi) under the order-Clupeiformes. It is important for principal lipids and in particular for highly unsaturated fatty acids which have potential biomedical benefits. Among the lipid classes, phospholipids were found to be the most predominant constituents than the glycolipid and neutral lipid in Amadi. Twenty six fatty acids were quantified by open tube gas–liquid chromatography. Dominant fatty acids in this fish are Palmitic acid (C16:0), Stearic acid (C18:0), Oleic acid (C18:1n?9), Myristic acid (C14:0), Palmitoleic acid (C16:1), Docosahexanoic acid (C22:6n?3), Pentadecanoic acid (C15:0), and Eicosatetraenoic acid (C20:4n?3). Fatty acid deficiency in fish species is indicated by the presence of C20:3n?9 acid. It is absent in this fish.The content of DHA and EPA are maximum in amount in neutral lipid than other lipid classes.  相似文献   

18.
Phosphoenolpyruvate carboxylase (PEPC) was purified from leaves of four species of Alternanthera differing in their photosynthetic carbon metabolism: Alternanthera sessilis (C3), A. pungens (C4), A. ficoides and A. tenella (C3-C4 intermediates or C3-C4). The activity and properties of PEPC were examined at limiting (0.05 mM) or saturating (10 mM) bicarbonate concentrations. The Vmax as well as Km values (for Mg2+ or PEP) of PEPC from A. ficoides and A. tenella (C3-C4 intermediates) were in between those of C3 (A. sessilis) and C4 species (A. pungens). Similarly, the sensitivity of PEPC to malate (an inhibitor) or G-6-P (an activator) of A. ficoides and A. tenella (C3-C4) was also of intermediate status between those of C3 and C4 species of A. sessilis and A. pungens, respectively. In all the four species, the maximal activity (Vmax), affinity for PEP (Km), and the sensitivity to malate (KI) or G-6-P (KA) of PEPC were higher at 10 mM bicarbonate than at 0.05 mM bicarbonate. Again, the sensitivity to bicarbonate of PEPC from C3-C4 intermediates was in between those of C3- and C4-species. Thus the characteristics of PEPC of C3-C4 intermediate species of Alternanthera are intermediate between C3- and C4-type, in both their kinetic and regulatory properties. Bicarbonate could be an important modulator of PEPC, particularly in C4 plants. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

19.
Lipid A in lipopolysaccharide (LPS) of Escherichia coli mutant strains was modified by the introduction of myristoyltransferase gene cloned from Klebsiella pneumoniae. When the gene was introduced into the mutant having lipid A containing only 3‐hydroxymyristic acids, it produced lipid A with two additional myristic acids (C14:0). When the same gene was introduced into the mutant with pentaacylated lipid A containing one lauric acid (C12:0), C12:0 was replaced by C14:0. IL‐6‐inducing activity of LPS with modified lipid A structure suggested that C12:0 in lipid A could be replaced by C14:0 without changing the immunostimulating activity.  相似文献   

20.
Abstract

A greenhouse experiment was conducted to examine the salt-induced changes in some key physio-biochemical attributes in eggplant (cv. New Noble) plants. Eggplant plants were grown under varying levels (0, 50, 100, and 150 mM) of sodium chloride under greenhouse conditions supplied with natural light and other climatic conditions. Varying saline regimes in growth medium significantly reduced the shoot and root fresh and dry weights, shoot and root lengths, relative water content, chlorophyll a and b pigments, photosynthetic rate (A), water-use efficiency, stomatal conductance (g s ), leaf and root K+, total phenolics, total soluble proteins, activity of superoxide dismutase (SOD), and leaf water and osmotic potentials in all eggplant plants. However, in contrast, saline regimes of the root growing medium did not affect transpiration rate (E), internal CO2 concentration (C i ), C i /C a ratio, photochemical quenching (qP), non-photochemical quenching, efficiency of photosystem-II (F v /F m ), leaf and root Ca2+ as well as ascorbic acid (AsA) contents in eggplant. A significant increase was observed in leaf turgor potential, free proline and glycinebetaine contents, leaf and root Na+ contents, malondialdehyde and hydrogen peroxide (H2O2) contents and activities of peroxidase (POD) and catalase (CAT) in eggplant plants under varying saline regimes. Overall, salt-induced growth reduction in eggplant plants was found to be associated with high accumulation of Na+ in both roots and shoots, which adversely affected photosynthetic capacity, chlorophyll pigments, K+ and Ca2+ contents, H2O2 and AsA levels and activities of SOD, POD, and CAT.  相似文献   

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