Variation of fragrance constituents in the leaves of Prunus

Hexane extracts from the leaves collected from 77 individual trees of the subgenera (Cerasus, Padus, Laurocerasus, and Prunus) in the genus Prunus were analyzed using gas chromatography, and the variations of linalool, phenethyl alcohol, and coumarin were investigated.     

Determination of hydralazine metabolites: 4-hydrazinophthalazin-1-one and n-acetylhydrazinophthalazin-1-one by gas chromatography and s-triazolo[3,4-a]phthalazine and phthalazinone by high-performance liquid chromatography

Methods are described for the determination of 4-N-acetylhydrazinophthalazin-1-one, 4-hydrazinophthalazin-1-one, phthalazinone and s-triazolo[3,4-a]phthalazine in human urine.4-Hydrazinophthalazin-1-one and 4-N-acetylhydrazinophthalazin-1-one (following acid hydrolysis) are reacted with acetylacetone to give a distinctive pyrazole derivative which can be determined by gas chromatography using a nitrogen-specific detector.Phthalazinone and s-triazolo[3,4-a]phthalazine are measured underivatised by high-performance liquid chromatography.     

Volatiles from spruce trap-trees detected by Ips typographus bark beetles: chemical and electrophysiological analyses

In the search for compounds that contribute to the host or habitat discrimination, antennae of Ips typographus were screened for sensitivity to volatiles released by spruce trap-trees using gas chromatography linked to electroantennography. The antennally active compounds were determined using comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometric detection. Data show that I. typographus antennae respond to compounds emitted by the host. In total, 18 of antennally active compounds were detected: α-pinene, camphene, sabinene, β-pinene, myrcene, Δ-3-carene, p-cymene, limonene, β-phellandrene, 1,8-cineole, γ-terpinene, terpinolene, nonanal, camphor, trans-pinocamphone, cis-pinocamphone, terpinen-4-ol, and verbenone. Unequivocal identification of all active minor compounds is provided and confirmed using synthetic standards. Compounds in minor quantities like 1,8-cineole, β-phellandrene, camphor, cis-pinocamphone, and trans-pinocamphone were more active than major spruce monoterpenes. We hypothesize that the minor spruce compounds may play so far unrecognized role in conveying information about host suitability for I. typographus.     

Subnanogram estimation of the proximate carcinogen N-hydroxy-2-fluorenylacetamide by gas-liquid chromatography

A very sensitive method, using electron-capture gas chromatography, has been developed for the quantitative estimation of N-hydroxy-2-fluorenylacetamide, the proximal carcinogenic metabolite of N-2-fluorenylacetamide. After incubation of the carcinogenic parent arylamide with rat liver microsomes, the N-hydroxy derivative produced is converted into N-chloro-2-fluorenylamine by treatment with hydrochloric acid; the amine is extracted with cyclohexane and transformed into N-chloro-2-fluorenyltrifluoroacetamide with trifluoroacetic anhydride. As little as 0.06 ng of the latter compound can be readily detected by gas-liquid chromatography using an electron-capture detector.     

Chemotaxonomic significance of leaf alkanes in species of Ficus (Moraceae)

The alkane pattern of leaf waxes from 24 tropical Ficus species in Nigeria was determined by gas chromatography and gas chromatography–mass spectrometry. Of the 12 alkanes identified, hentriacontane and tritriacontane were the major components in all the species studied. The chemosystematic significance of leaf alkanes is discussed in Ficus for the first time. There is an indication that alkane occurrence in Ficus could provide useful information to the understanding of species variability.     

Identification of 6-0-beta-D-galactopyranosyl myo-inositol: a new form of myo-inositol in mammals

A disaccharide has been isolated from the mammary gland of rats on the 18th day of lactation and identified as 6-O-β-D-galactopyranosyl myo-inositol (6-β-galactinol). The structure was established using chemical and enzymatic methods, paper and gas chromatography, and combined gas chromatography-mass spectrometry. This is the first report of a myo-inositol galactoside of animal origin.     

Gas chromatography with nitrogen-selective detection of metoprolol from human plasma after reaction with phosgene

A method for the determination of therapeutic levels of metoprolol in human plasma is presented. Metoprolol and the internal standard are extracted from the buffered plasma sample to an organic phase containing 4 x 10^?3M phosgene. After 10 min the organic phase is taken to dryness. The residue is dissolved in ethyl acetate and the formed oxazolidine derivatives are analyzed by gas chromatography with nitrogen-selective detection. With packed columns, rectilinear standard curves through the origin were obtained down to 80 nmoles/l of plasma. The precision of the method at 200 nmoles/l was 1.5% (n = 8). The sensitivity of the method was improved by using capillary column gas chromatography. Linear standard curves were obtained down to 10 nmoles/1 of metoprolol in plasma. The precision of the method at the 50 nmoles/1 level was 2.2% (n = 7). With this simple and straightforward method using extractive derivatization 30 samples can be handled in a day.     

The composition of suberin from the corks of Quercus suber L. and Betula pendula roth

The suberin constituents of Quercus suber and Betula pendula have been isolated after alkaline hydrolysis of the corks and over 80% by weight identified using thin-layer chromatography, preparative thin-layer chromatography, gas-liquid chromatography and combined gas chromatography — mass spectrometry. Long-chain aliphatic acids ranging from C₁₆–C₂₆ comprise about 90% of both suberin fractions; monobasic, α,ω-dibasic, ω-hydroxymonobasic, dihydroxymonobasic, dihydroxydibasic and trihydroxymonobasic acid classes are present. The principal suberin acids of Q. suber are 18-hydroxyoctadecenoic (12%), 22-hydroxydocosanoic (25%), 9,10-dihydroxyoctadecane-1,18-dioic (15%) and 9,10,18-trihydroxyoctadecanoic (8%), and those of B. pendula 9,10,18-trihydroxyoctadecanoic (43%) and 22-hydroxydocosanoic (16%).     

Separation of brain phosphatidylserines according to degree of unsaturation by thin-layer chromatography

Phosphatidylserines (PS) have been prepared from bovine brain using DEAE column chromatography. A method involving AgNO₃-impragnated silica gel H thin-layer chromatography is presented for separating intact PS according to the degree of unsaturation of their fatty acids. A detailed analysis was made of the fatty acid composition of the various fractions using gas chromatography. Some data are presented on the composition of molecular species of PS in bovine brain. The two main molecular species found in cerebral cortex are tentatively assigned the structures of 1-octadecanoyl-2-docosahexaenoyl-sn-glycero-3-phosphorylserine and 1-octadecanoyl-2-octadecenoyl-sn-glycero-3-phosphorylserine.     

Quantitative determination of prostaglandins E1 and F1α by multiple ion analysis

Quantitative assays for prostaglandins (PG) E₁ and PGF_1α are described using [3,3,4,4,5,6-²H₆]labeled prostaglandins as carriers and methyl ester-O-methyloxime-acetate (PGE₁) and methyl ester-acetate (PGF_1α) derivatives for gas - liquid chromatography/mass spectrometric analysis. Thin-layer argentation chromatography was used to separate PGE₁ from PGE₂ and 13, 14-dihydro-PGE₂. These latter compounds, which do not separate from PGE₁ using conventional thin-layer chromatography or under the gas - liquid chromatographic conditions used, can significantly interfere with the quantitative analysis of PGE₁. The method described prevents this interference and is therefore suitable for the accurate analysis of PGE₁ in biological samples containing a high concentration of PGE₂ and/or 13, 14-dihydro-PGE₂.     

Analyses of volatiles produced by the African fruit fly species complex (Diptera,Tephritidae)

Ceratitis fasciventris, Ceratitis anonae and Ceratitis rosa are polyphagous agricultural pests originating from the African continent. The taxonomy of this group (the so-called Ceratitis FAR complex) is unclear. To clarify the taxonomic relationships, male and female-produced volatiles presumably involved in pre-mating communication were studied using comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry (GC×GC-TOFMS) followed by multivariate analysis, and gas chromatography combined with electroantennographic detection (GC-EAD). GC×GC-TOFMS analyses revealed sex specific differences in produced volatiles. Male volatiles are complex mixtures that differ both qualitatively and quantitatively but share some common compounds. GC-EAD analyses of male volatiles revealed that the antennal sensitivities of females significantly differ in the studied species. No female volatiles elicited antennal responses in males. The results show clear species-specific differences in volatile production and provide complementary information for the distinct delimitation of the putative species by chemotaxonomic markers.     

Cloning of fusaric acid-detoxifying gene from Cladosporium werneckii: a new strategy for the prevention of plant diseases

Fusaric acid-detoxifying gene from Cladosporium werneckii was cloned in Escherichia coli. The detoxification of fusaric acid was confirmed chemically by gas chromatography and biologically by using tomato callus cells. The damage caused by fusaric acid was dramatically diminished in tomato cuttings pretreated with E. coli cells containing the cloned plasmid. The findings suggest that genetically engineered microbes could be applicable to the protection of plants from diseases caused by fusaric acid-producing pathogens.     

Characterization of Salmonella and possible interfering strains using GC profiling and factor analysis

Fatty acid methyl ester data of Salmonella and potentially interfering strains obtained by derivatization gas chromatography were investigated with principal components and factor-discriminant analysis. Salmonella strains could be distinguished using both data-handling techniques. The biochemical basis for this characterization was found to be in strong agreement with the higher mass range part of pyrolysis — direct chemical ionization mass spectrometric data representing diglyceride information. The quality of the analytical procedure as judged by longer term reproducibility and component assignment was found to be good. In combination with sophisticated data-handling methods this derivatization gas chromatographic approach can be a useful diagnostic tool for Salmonella characterization.     

Sex pheromone precursors in Spodoptera littoralis (Lepidoptera: Noctuidae)

Female pheromone gland extracts of Spodoptera littoralis were analyzed for pheromone precursors. Large amounts of fatty methyl esters were found and a positive relationship between the methyl esters and the pheromonal components was observed. The esters were identified on the basis of capillary gas chromatography, coupled gas chromatography with mass spectroscopy and dimethyl disulfide derivatization, and subsequent gas chromatography with mass spectrometry. The characteristic fatty esters of S. littoralis are methyl (Z)-9-tetradecenoate, (E)- and (Z)-11-tetradecenoate, (Z,E)-9,12-tetradecadienoate, (Z,E)-9,11-tetradecadienoate, and (Z)-11-hexadecenoate. The biosynthesis of the monosaturated acids involves probably the common E11 and Z11 desaturases and chain shortening. For the biosynthesis of the novel diene acids, we propose a second, specific desaturation of (Z)-9-tetradecenoate by an E11 desaturase to produce (Z,E)-9,11-tetradecadienoate or by an E12 desaturase to produce (Z,E)-9,12-tetradecadienoate.     

Production and characterization of Escherichia coli glycerol dehydrogenase as a tool for glycerol recycling

NAD⁺-dependent glycerol (Gro) dehydrogenase (GroDHase) catalyzes the conversion of Gro into dihydroxyacetone (DHA), the first step for fermentative Gro metabolism in Escherichia coli. In this work, we cloned the gldA gene that codes for the E. coli GroDHase and homologously expressed, purified, and kinetically characterized the recombinant protein. To achieve this, the enzyme was over-produced using Gro supplemented growth medium and lactose as the inducer. The enzyme was highly purified using either pseudo-affinity chromatography or a simple heat-shock treatment, which is potentially valuable for industrial production of GroDHase. We detected efficient oxidation of Gro derived from biodiesel production to DHA by gas chromatography. The results presented in this work support recombinant GroDHase production in a biorefinery setting as a relevant tool for converting Gro into DHA for future biotechnological applications.     

Cleavage of L-leucine-containing dipeptides by Clostridium butyricum

The ability of Clostridium butyricum cultures to hydrolyze three L-leucine-containing dipeptides (Leu-Leu, Leu-Gly and Gly-Leu) in a synthetic minimal medium is demonstrated by using gas chromatography coupled with mass spectrometry. The ¹³C nuclear magnetic resonance and a labeled dipeptide L-[1-¹³C]Leu-Gly were used to confirm this activity.     

Identification of 6-O-alpha-D-mannopyranosyl myo-inositol from Saccharomyces cerevisiae

A mannosyl inositol isolated from Baker's yeast was shown to be α-linked from the 1 position of mannose to the 6 position of myo-inositol by comparison of the products of permethylation, hydrolysis, and reduction of the disaccharide. The structure was established using chemical and enzymatic methods, gas chromatography, and combined gas chromatographymass spectrometry.     

Oxygenation of methane by methane-utilizing bacteria.

1. Experimental conditions have been found in which small amounts of methanol (approximately 2.5mm) accumulated when washed cell suspensions of methane-grown Pseudomonas methanica and Methanomonas methanooxidans were incubated with methane+oxygen mixtures in Warburg flasks. 2. The methanol formed could be separated completely from water by fractional distillation through glass helices followed by gas chromatography using 20% polyethylene glycol 400 on a Celite 545 support. 3. By using ¹⁸O-enriched oxygen gas the abundance of ¹⁸O in the methanol formed from oxidation of methane was measured with a Perkin–Elmer 270 combined gas chromatograph/mass spectrometer. The results showed that the oxygen in methanol was derived exclusively from gaseous oxygen in both micro-organisms. 4. Control experiments using [¹⁸O]water in incubation mixtures confirmed that there was negligible incorporation of the oxygen atom from water into methanol.     

Stereospecific formation of 1,2-epoxypropane, 1,2-epoxybutane and 1-chloro-2,3-epoxypropane by alkene-utilizing bacteria

Resting cells of ethene grown Mycobacterium 2W produced 1,2-epoxypropane stereospecifically from propene as revealed by optical rotation, ¹H n.m.r. using a chiral shift reagent, and also by complexation gas chromatography involving a glass capillary column coated with an optically active metal chelate. The gas-liquid chromatography method allowed the rapid screening of 11 strains with regard to stereospecific formation of 1,2-epoxypropane, 1,2-epoxybutane and 1-chloro-2,3-epoxypropane. Bacteria grown on either ethene, propene or butadiene all predominantly produced the R form of 1,2-epoxypropane from propene and 1,2-epoxybutane from 1-butene while the strains tested for 1-chloro-2,3-epoxypropane production from 3-chloro-1-propene predominantly accumulated the S enantiomer.     

A simultaneous assay system for N-acetylgalactosamine and N-acetylgalactosaminitol using gas chromatography/mass spectrometry

A procedure is described, using gas chromatography/mass spectrometry to identify and quantitate various sugar alditol acetates, which will simultaneously quantitate N-acetylgalactosamine and N-acetylgalactosaminitol. N-acetylgalactosamine is distinguished from N-acetylgalactosaminitol by reduction with sodium borodeuteride and determining relative intensities of the ion pairs $\text{m}\text{e}$ 84, 85; 102, 103; and 144, 145. The method is adequate for determining amounts of these sugars in the range of 40–1000 nmol.