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1.
Palynofacies and molecular organic geochemical analyses indicate a probable lacustrine origin for three organic-rich black shale samples from the lowermost Pular Formation (Permo–Carboniferous) of northern Chile. The three samples examined exhibit high values for total organic carbon and hydrogen indices. Biomarkers and stable carbon isotopic compositions (−36.5 to −35.5‰) are typical for oil-prone type I organic matter associated with lacustrine source rocks and derived oils. Amorphous kerogen dominates the samples, and two distinct palynofacies can be recognized. The palynofacies can be visually distinguished by the presence/absence of petrofilaments, presence/absence of terrestrial organic material, and weak versus strong fluorescence. These organic facies can also be separated using hydrogen indices, the abundance of n-C24+ paraffins, sterane (C27, C28, C29) patterns, and the relative amounts of perhydro-β-carotene.  相似文献   

2.
Klaus Haas 《Phytochemistry》1982,21(3):657-659
The mosses Andreaea rupestris, Pogonatum aloides and P. urnigerum contain surface waxes in amounts of 0.05–0.12% dry wt. The waxes consisted of esters (C38-C54), primary alcohols (C20-C32), free fatty acids (C16-C30), and alkanes (C21-C31). Additionally, aldehydes (C22-C30) were major constituents in the wax of P. urnigerum. The classes and their chain length distributions in the surface waxes of these mosses are comparable to those of epicuticular waxes of higher plants.  相似文献   

3.
The hydrocarbon constituents of the leaf waxes of eight species of Khaya were analysed for taxonomic purposes using GLC. The leaf waxes contained neither isoalkanes nor alkanes and the bulk of the n-alkanes were in the range of C25 to C33, odd-carbon number compounds predominating. It was found that the percentage composition of the n-alkane constituents of the leaf waxes varied with the age of leaves, young leaves having n-C29 as the most abundant alkane, whereas older leaves had n- C31.  相似文献   

4.
The leaf alkanes of Parthenium argentatum (guayule), P. tomentosum var. stramonium, P. fruticosum var. trilobatum, and the first filial (F1) generations obtained from crosses with guayule were investigated by GC and mass spectrometry and shown to be useful in chemotaxonomic studies. The identified n-alkanes ranged from C19 to C40 with either n-C29 or n-C31 as the main component. The alkane chemistry of guayule with n-C31 being the main component predominated in most of the F1 hybrids. The presence of iso-branched alkanes (C27, C29, C31) in P. tomentosum and its hybrids could be detected by GC/MS. These preliminary investigations indicate that epicuticular wax alkanes can be useful in inheritance studies of guayule and its hybrids.  相似文献   

5.
Pseudomonas aeruginosa strain WatG was unable to utilize either n-hexatriacontane (C36) or n-tetracontane (C40), which are both insoluble in a mineral salts medium (MSM), as a sole carbon source. However, when C36 and C40 were added to MSM containing crude oil, more than 25% of each of the compounds was degraded by this strain after 2 weeks at 30 °C. These results demonstrate that P. aeruginosa strain WatG has the ability to degrade long-chain alkanes up to C40, when they are solubilized by crude oil components.  相似文献   

6.
Eleven strains of hydrocarbon-oxidizing bacteria, isolated from oilfields and representing the genera Rhodococcus, Gordonia, Dietzia, and Pseudomonas, were characterized as mesophiles and neutrophiles. Rhodococci were halotolerant microorganisms growing in a media containing up to 15% NaCl. All the strains oxidized n-alkanes of crude oil. An influence of the cultivation temperatures (28 or 45°C) and organic supplements on the degradation of C12-C30 n-alkanes in oxidized oil by two bacterial strains of the genus Pseudomonas was shown. The introduction of acetate, propionate, butyrate, ethanol, and sucrose led mainly to decreased oxidation of petroleum paraffins. At certain cultivation temperatures, the addition of volatile fatty acid salts increased the content of certain n-alkanes in oxidized oil as compared to crude oil.  相似文献   

7.
The hexane extract of Wyethia mollis contains the n-alkanes C15-C18, C20-C25, C27 and C29. Linoleic acid was the only detectable acidic component. A mass spectral analysis of the wax ester fraction indicated that it was a mixture of homologues, the saturated even-carbon acids n-C16-C30 esterfield with the saturated even-carbon alcohols n-C18-C26. The chloroform extract yielded the known isoflavones santal and 3′-O-methylorobol along with a new lanostane-type triterpene, 22,25-epoxy-lanosta-7:9(11)-dien-3-one. The wide distribution of n-alkanes and the decreased odd-even carbon ratio are consistent with the proposed primitive nature of this plant.  相似文献   

8.
From the aerial parts of Canscora decussata Schult (Gentianaceae), five triterpenes, viz. gluanone, canscoradione, friedelin, fridelan-3-β-ol, and β-amyrin, three sterols, viz. sitosterol, stigmasterol, and campesterol, besides liberal amount of a mixtures of n-alkanes (C27-C31) and n-alkanols (C26-C32) have been isolated. The identity of the compounds has been established by chemical transformations, spectral evidence, and by direct comparison, where possible, with authentic reference materials. Gluanone and canscoradione have not been encountered before in nature.  相似文献   

9.
10.
Ultrastructural studies of leaves of seven Panicum species in or closely related to the Laxa group and classified as C3, C4 or C3-C4 intermediate were undertaken to examine features associated with C3 and C4 photosynthesis. The C3 species Panicum rivulare Trin. had few organelles in bundle sheath cell profiles (2 chloroplasts, 1.1 mitochondria, and 0.3 peroxisomes per cell section) compared to an average of 10.6 chloroplasts, 17.7 mitochondria, and 3.2 peroxisomes per bundle sheath cell profile for three C3-C4 species, Panicum milioides Nees ex Trin., Panicum decipiens Nees ex Trin. and Panicum schenckii Hack. However, two other C3 species, Panicum laxum Sw. and Panicum hylaeicum Mez, contained about 0.7, 0.5, and 0.3 as many chloroplasts, mitochondria, and peroxisomes, respectively, as in bundle sheath cell profiles of the C3-C4 species. Chloroplasts and mitochondria in bundle sheath cells were larger than those in mesophyll cells for the C4 species Panicum prionitis Griseb. and the C3-C4 species, but in C3 species the organelles were similar in size or were smaller in the bundle sheath cells. The C3-C4 species and P. laxum and P. hylaeicum exhibited an unusually close association of organelles in bundle sheath cells with mitochondria frequently surrounded in profile by chloroplasts. The high concentrations in bundle sheath cells of somewhat larger organelles than in mesophyll cells correlates with the reduced photorespiration of the C3-C4 species.  相似文献   

11.
The molecular and isotopic compositions of lipid biomarkers of cultured Aquificales genera have been used to study the community and trophic structure of the hyperthermophilic pink streamers and vent biofilm from Octopus Spring. Thermocrinis ruber, Thermocrinis sp. strain HI 11/12, Hydrogenobacter thermophilus TK-6, Aquifex pyrophilus, and Aquifex aeolicus all contained glycerol-ether phospholipids as well as acyl glycerides. The n-C20:1 and cy-C21 fatty acids dominated all of the Aquificales, while the alkyl glycerol ethers were mainly C18:0. These Aquificales biomarkers were major constituents of the lipid extracts of two Octopus Spring samples, a biofilm associated with the siliceous vent walls, and the well-known pink streamer community (PSC). Both the biofilm and the PSC contained mono- and dialkyl glycerol ethers in which C18 and C20 alkyl groups were prevalent. Phospholipid fatty acids included both the Aquificales n-C20:1 and cy-C21, plus a series of iso-branched fatty acids (i-C15:0 to i-C21:0), indicating an additional bacterial component. Biomass and lipids from the PSC were depleted in 13C relative to source water CO2 by 10.9 and 17.2‰, respectively. The C20–21 fatty acids of the PSC were less depleted than the iso-branched fatty acids, 18.4 and 22.6‰, respectively. The biomass of T. ruber grown on CO2 was depleted in 13C by only 3.3‰ relative to C source. In contrast, biomass was depleted by 19.7‰ when formate was the C source. Independent of carbon source, T. ruber lipids were heavier than biomass (+1.3‰). The depletion in the C20–21 fatty acids from the PSC indicates that Thermocrinis biomass must be similarly depleted and too light to be explained by growth on CO2. Accordingly, Thermocrinis in the PSC is likely to have utilized formate, presumably generated in the spring source region.  相似文献   

12.
Conversion of CO2 to organic compounds in hydrothermal systems is important in understanding prebiotic chemical evolution leading to the origin of life. However, organic compounds with carbon number of more than 3 have never been produced from dissolved CO2 in simulated hydrothermal experiments. In this paper, we report that not only CH4, C2H6 and C3H8, but also n-C4H10 and n-C5H12 could be produced from dissolved CO2 and H2 in the presence of cobalt-bearing magnetite at 300°C and 30 MPa. It is shown that unbranched alkanes in Anderson–Schulz–Flory distribution were the dominant hydrocarbon products produced from dissolved CO2 catalyzed by cobalt-bearing magnetite under certain hydrothermal conditions. It is proposed that magnetite with other transition metals may act potentially as effective mineral catalysts for abiotic formation of organic compounds from dissolved CO2 in hydrothermal systems.  相似文献   

13.
The optimized geometries, electron affinities, and dissociation energies of the alkylthio radicals have been determined with the higher level of the Gaussian-3(G3) theory. The geometries are fully optimized and discussed. The reliable adiabatic electron affinities with ZPVE correction have been predicted to be 1.860 eV for the methylthio radical, 1.960 eV for the ethylthio radical, 1.980 and 2.074 eV for the two isomers (n-C3H7S and i-C3H7S) of the propylthio radical, 1.991, 2.133 and 2.013 eV for the three isomers (n-C4H9S, t-C4H9S, and i-C4H9S) of the butylthio radical, and 1.999, 2.147, 2.164, and 2.059 eV for the four isomers (n-C5H11S, b-C5H11S, c-C5H11S, and d-C5H11S) of the pentylthio radical, respectively. These corrected EAad values for the alkylthio radicals are in good agreement with available experiments, and the average absolute error of the G3 method is 0.041 eV. The dissociation energies of S atom from neutral CnH2n+1S (n?=?1–5) and S- from corresponding anions CnH2n+1S- species have also been estimated respectively to examine their relative stabilities.  相似文献   

14.
In spite of the importance of feces in scent marking and intraspecific chemical communication of many mammals, only a few studies have examined the chemical constituents of feces that could have a signaling function. We described here the chemicals found in feces recently deposited in the wild by adult and pup Iberian wolves (Canis lupus signatus). By means of analyses using gas chromatography–mass spectrometry (GC–MS), we identified 77 compounds in feces of adult wolves, mainly heterocyclic aromatic organic compounds, such as indole or phenol, but also steroids, such as cholesterol, carboxylic acids and their esters between n-C3 and n-C18, aldehydes, alcohols and significant quantities of squalene and α-tocopherol, which would increase the chemical stability of feces on humid substrates. Some of the odoriferous compounds are very likely originated in the anal-sac secretions, and later incorporated onto feces during defecation. However, the abundance of the main odoriferous compounds in feces could be explained by the result of the bacterial action on food components. Feces of pups only had 26 compounds, most of these were also found in adults’ feces, but four compounds were only found in pups’ feces, and there were also age-related differences respect to the proportions of shared chemicals. These differences could be partly due to the absence of anal-sac glands in pups, which would not need to scent mark substrates.  相似文献   

15.
Extraction, thin-layer chromatography, and gas chromatography–mass spectrometry of leaf surface waxes of Momordica charantia L. (Cucurbitaceae) revealed that 20 n-alkanes between n-C15 and n-C36, except n-C34 and n-C35, commonly occur in young, mature, and senescent stages. Hentriacontane, hentriacontane, and hexatriacontane were the predominant compounds in young, mature, and senescent leaves, respectively. The cuticular alkanes from young, mature, and senescent leaves attracted the female insect, Epilachna dodecastigma (Wied.), at 25–400, 25–400, and 100–400 μg concentrations, respectively, whereas the mixtures of synthetic alkanes mimicking cuticular alkanes of young, mature, and senescent leaves showed attraction at 100–400, 100–400, and 200–400 μg concentrations, respectively, in Y-shaped glass tube olfactometer bioassay. The difference in insect attraction is probably due to the absence of branched-chain alkanes in the synthetic mixtures. Individual synthetic heptacosane, nonacosane, and hentriacontane at 28.19–56.90, 32.04–64.08, and 60.44–120.88 μg, respectively, elicited attraction of the insect. A synthetic blend of 4.82, 4.91, 5.71, 6.74, 56.39, 7.94, 62.42, 120.88, and 36.33 μg of nonadecane, eicosane, heneicosane, pentacosane, heptacosane, octacosane, nonacosane, hentriacontane, and tritriacontane, respectively, was most attractive to the insect.  相似文献   

16.
Byrd GT  Brown RH 《Plant physiology》1989,90(3):1022-1028
The possibility of altering CO2 exchange of C3-C4 species by growing them under various CO2 and O2 concentrations was examined. Growth under CO2 concentrations of 100, 350, and 750 micromoles per mole had no significant effect on CO2 exchange characteristics or leaf anatomy of Flaveria pringlei (C3), Flaveria floridana (C3-C4), or Flaveria trinervia (C4). Carboxylation efficiency and CO2 compensation concentrations in leaves of F. floridana developed under the different CO2 concentrations were intermediate to F. pringlei and F. trinervia. When grown for 12 days at an O2 concentration of 20 millimoles per mole, apparent photosynthesis was strongly inhibited in Panicum milioides (C3-C4) and to a lesser degree in Panicum laxum (C3). In P. milioides, acute starch buildup was observed microscopically in both mesophyll and bundle sheath cells. Even after only 4 days exposure to 20 millimoles per mole O2, the presence of starch was more pronounced in leaf cross-sections of P. milioides compared to those at 100 and 210 millimoles per mole. Even though this observation suggests that P. milioides has a different response to low O2 with respect to translocation of photosynthate or sink activity than C3 species, the concentration of total available carbohydrate increased in shoots of all species by 33% or more when grown at low O2. This accumulation occurred even though relative growth rates of Festuca arundinacea (C3) and P. milioides grown for 4 days at 210 millimoles per mole O2, were inhibited 83 and 37%, respectively, when compared to plants grown at 20 millimoles per mole O2.  相似文献   

17.
In isolated tobacco leaves l-valine-U-14C gave rise to labeled even-numbered isobranched fatty acids containing 16 to 26 carbon atoms and iso C29, iso C31, and iso C33 paraffins. l-Isoleucine-U-14C on the other hand produced labeled odd-numbered anteiso C17 to C27 fatty acids and anteiso C30 and C32 paraffins. Trichloroacetic acid inhibited the incorporation of isobutyrate into C20 and higher fatty acids and paraffins without affecting the synthesis of the C16 and C18 fatty acids. Thus the very long branched fatty acids are biosynthetically related to the paraffins. In Senecio odoris leaves acetate-1-14C was incorporated into the paraffins (mainly n-C31) only in the epidermis although acetate was readily incorporated into fatty acids in the mesophyll tissue. Similarly only the epidermal tissue incorporated acetate into fatty acids longer than C18 suggesting that the epidermis is the site of synthesis of both paraffins and the very long fatty acids. In broccoli leaves n-C12 acid labeled with 14C in the carboxyl carbon and 3H in the methylene carbons was incorporated into C29 paraffin without the loss of 14C relative to 3H. Since n-C18 acid is known to be incorporated into the paraffin without loss of carboxyl carbon these results suggest that the condensation of C12 acid with C18 acid is not responsible for n-C29 paraffin synthesis in this tissue. Thus all the experimental evidence thus far obtained strongly suggests that elongation of fatty acids followed by decarboxylation is the most likely pathway for paraffin biosynthesis in leaves.  相似文献   

18.
The long-chain saturated and mono-unsaturated hydrocarbon content of the juice sacs of five mandarin cultivars (Mediterranean, Honey, Wilking, Kinnow, King) were examined. Normal homologues accounted for more than 47% of the saturated and more than 75% of the monoene hydrocarbons. In the saturated fraction the major hydrocarbon was n-C25 but in the monoene fraction n-C25 predominated in Kinnow and King while C29 predominated in Mediterranean, Honey and Wilking. All five cultivars could be differentiated from each other and from other citrus species by their hydrocarbon patterns. The noticeably high normal/iso ratios of saturated C23 and C25 hydrocarbons previously shown to be characteristic of mandarin species, Citrus unshiu and C. reticulata, were also found in C. nobilis and C. deliciosa.  相似文献   

19.
《农业工程》2014,34(5):277-283
Lipid biomarkers of microorganism and vegetation preserved in penguin droppings record historical changes in the West Antarctic climate and environment. n-Alkanes, fatty acids and coprostanols have been determined in sediment core AD6 from penguin droppings in Ardley Island, West Antarctica, using GC or GC/MS/SIM. For n-alkanes, the main carbon number was nC23 with single-peak pattern, ΣC21/ΣC22+ value was from 0.27 to 0.61, the carbon preference index (CPI) was from 2.97 to 6.12 with significant odd–even predominance (OEP), and these indicate that the vegetation was dominated by mosses and lichens. For fatty acids, the main carbon numbers were nC16:0 and nC24:0 with double-peak pattern, ΣC21/ΣC22+ value was from 0.35 to 0.77, and the relative abundance ratio of even:odd carbon (CPIA) was from 2.88 to 6.40 with significant OEP. Bacteria invasion index ((iC15:0 + aC15:0)/nC15:0 for fatty acids) showed high contribution of bacteria during 1977–1982, 1948–1953 and 1920–1925, indicating enhanced microbial activities. Meanwhile, CPIA values decreased and extreme microbes contributed fatty acids with low carbon number to penguin dropping strata. Furthermore, the concentration of cholestanol and ratio of cholestanol/cholesterol in penguin dropping strata changed correspondingly, indicating that the microbial degradation played a major role in the increasing ratio of cholestanol/cholesterol during the sedimentation process. The down-core profiles of n-alkanes, fatty acids and coprostanols in penguin dropping strata indicate that extreme microorganism and bacteria play important roles in the relatively simple Antarctic ecological system associated with climate conditions.  相似文献   

20.
The geometrical structures, energetics properties, and aromaticity of C36-n Si n (n?≤?18) fullerene-based clusters were studied using density functional theory calculations. The geometries of C36-n Si n clusters undergo strong structural deformation with the increase of Si substitution. For the most energy favorable structures of C36-n Si n , the silicon and carbon atoms form two distinct homogeneous segregations. Subsequently, the binding energy, HOMO–LUMO energy gap, vertical ionization potential, vertical electron affinity, and chemical hardness for the energetic favorable C36-n Si n geometries were computed and analyzed. In addition, the aromatic property of C36-n Si n cagelike clusters was investigated, and the result demonstrate that these C36-n Si n cagelike structures possess strong aromaticity.  相似文献   

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