Double bond location in monounsaturated wax esters by gas chromatography/mass spectrometry of their dimethyl disulphide derivatives

Pèpe, Claude; Dagaut, J.; Scribe, P.; Saliot, A.

doi:10.1002/oms.1210281113

Cited by 20 publications

(14 citation statements)

References 17 publications

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“…The fatty acyl side chain inventory was analyzed by gas chromatography (GC)-MS after trans-esterification of the phospholipid fraction to obtain the methylated formerly phospholipid-linked fatty acids using the method described by Mueller et al (41). The position of the double bond(s) in unsaturated phospholipid-linked fatty acids (PLFAs) was determined as described by Pepe et al (50).…”

Section: Shotgun Proteomics By Liquid Chromatography-electrospray Ionmentioning

confidence: 99%

Physiological and Proteomic Adaptation of “Aromatoleum aromaticum” EbN1 to Low Growth Rates in Benzoate-Limited, Anoxic Chemostats

et al. 2012

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؊1 ) growth rates. A positive correlation to growth rate was observed for cellular parameters (cell size, and DNA and protein contents). The free energy consumed for biomass formation steadily increased with growth rate. In contrast, the energy demand for maintenance increased only from low to med and then remained constant until high . The most comprehensive proteomic changes were observed at low compared to high . Uniformly decreased abundances of protein components of the anaerobic benzoyl coenzyme A (benzoyl-CoA) pathway, central carbon metabolism, and information processing agree with a general deceleration of benzoate metabolism and cellular processes in response to slow growth. In contrast, increased abundances were observed at low for diverse catabolic proteins and components of uptake systems in the absence of the respective substrate (aromatic or aliphatic compounds) and for proteins involved in stress responses. This potential catabolic versatility and stress defense during slow growth may be interpreted as preparation for future needs. Most terrestrial and aquatic habitats are characterized by dynamic fluctuations in the composition and concentration of nutrients, supporting heterotrophic growth of bacteria in a feastand-famine manner. In most cases, poor carbon and nutrient availabilities restrict or even arrest microbial growth (see, e.g., references 19, 27, and 33). Thus, the capacity of bacteria to cope with nutrient limitation is a key determinant for their survival and success in the environment. Substrate limitation and its longknown intimate coupling to bacterial growth rates are best studied by continuous cultivation in chemostats (for an overview, see, e.g., references 20 and 27). Constrained by a defined and constant supply of the limiting nutrient at a specific rate (dilution rate [D]), the bacterial population in a chemostat approaches a steady state characterized by a specific growth rate () and stable growth parameters (39, 45). Combining these quantities with chemostat models can describe the dynamics of bacterial populations at many levels (see, e.g., reference 25).Steady-state responses are best understood in Escherichia coli and other enterobacteria. Early physiological studies revealed a tight coupling of growth rate with the size and molecular composition of cells (7,42,61). Subsequently, growth rate-dependent global alterations in gene expression (21, 30) and proteome signatures (49, 76) were observed. An interesting outcome from these global surveys of slowly growing, carbon-limited cells was the apparently preemptive adaptation to future needs for stress resistance and multiple substrate utilization (for an overview, see reference 19).The denitrifying strain "Aromatoleum aromaticum" EbN1 is a versatile aquatic betaproteobacterium that anaerobically degrades 24 different monoaromatic compounds, including petroleum hydrocarbons (57), phenolic solvents (79), and 3-phenylpropanoids (69). With few exceptions, these aromatic substrates are channeled via specific reaction sequences i...

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Section: Shotgun Proteomics By Liquid Chromatography-electrospray Ionmentioning

confidence: 99%

Physiological and Proteomic Adaptation of “Aromatoleum aromaticum” EbN1 to Low Growth Rates in Benzoate-Limited, Anoxic Chemostats

et al. 2012

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“…The product resulting of the reaction between this compound and the DMDS is a four-membered cyclic thioether since only one methylene group separates the double bonds [1][2][3][4][5][6].…”

Section: Resultsmentioning

confidence: 99%

“…If the number of methylene groups which separates the two double bonds is less than 4, a cyclic thioether is formed and the fragmentation observed, after electron impact at 70 eV, has permitted unequivocal determination of the double bond positions for alkadienes and esters [1][2][3][4][5][6].…”

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confidence: 99%

Study of the fragmentation pathways of dimethyl disulfide derivative of 2-methyl-1,4-pentadiene by GC/MS to locate the double bonds in substituted unsaturated compounds

Pèpe¹,

Sayer²,

Ledoux³

et al. 1999

Analusis

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The determination of the double bond positions in mono and diunsaturated esters has been studied by using their dimethyl disulfide (DMDS) derivatives. If the number of methylene groups which separates the two double bonds is less than 4, a cyclic thioether is formed and the fragmentation observed, after electron impact at 70 eV, has permitted unequivocal determination of the double bond positions for alkadienes and esters [1][2][3][4][5][6].The DMDS derivative (a cyclic thioether) of 2-methyl-1,4-pentadiene has been studied by mass spectrometry in a previous paper [7]. The mass spectrum (Fig. 1) shows the presence of a base peak at m/z 113 and fragment ions at m/z 161 and 147 resulting of the loss of CH 3 S • or CH 3 SCH 2 • respectively from the molecular ion. In turn, these fragment ions m/z 161 and 147 lose methanethiol (CH 3 SH) to give respectively the ions at m/z 113 and 99. This loss of CH 3 SH is essential for interpretation of the mass spectra of DMDS derivatives of unsaturated compounds and to locate the double bonds.The structures of the fragment ions at m/z 113 and 99 were investigated by using ab initio calculations, in particular by calculation of the values of the relative energies of the isomeric structures. In each case, the loss of CH 3 SH was considered as a migration of the hydrogen atom bonded to the carbon atom in the β-position relative to the sulfur atom.We report in this work a study of the loss of CH 3 SH by migration of a hydrogen atom no bonded to C in the β-position relative to the sulfur atom. ExperimentalSample preparations and mass spectrometry 2-methyl-1,4-pentadiene and 2,4-dimethyl-1,4-pentadiene (50 µg) were treated in 100 µL of hexane by addition of 100 µL of DMDS and a solution of 20 µL of iodine (60 mg of iodine in 1 mL of diethyl ether). The reaction was carried out in a closed tube for two days at 50 °C. The excess of iodine was reduced with sodium thiosulfate solution (5% in water). The organic phase was removed and the excess of DMDS was evaporated. The dry extract was diluted with 50 µL of hexane and then analysed by GC/MS.To synthesize the 2,4-dimethyl-1,4-pentadiene, 10 mL of a solution of isopropenylmagnesium bromide (0.5 mol L -1 ) in THF were added dropwise under N 2 and moderate stirring to 0.4 mL of 3-chloro-2-methyl-propene, then shaken at room temperature during 12 hours. The mixture was hydrolysed by 1 mL of NH 4 Cl satureted solution, dried over Na 2 SO 4 , and distilled under atmospheric pressure.Electron ionization mass spectra were obtained using a Nermag R10-10 quadrupole mass spectrometer coupled to a Varian Model 3400 gas chromatograph. The sample was Abstract. An experimental study has been employed to examine the loss of CH 3 SH from the dimethyl disulfide (DMDS) derivative of 2-methyl-1,4-pentadiene (cyclic thioether). This loss is particulary important to locate the double bonds in mono, di and tri-unsaturated compounds after addition of DMDS. This work shows that the migration of a H atom in the β or in a other position relative to the sulfur atom...

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“…Dithiomethyl disulfide (DMDS) derivatives of the alkenes present in the hydrocarbon mixture were prepared by the method developed by Pepe et al (1993) involving the derivatization of monounsaturated wax esters. Twenty microlitres of an ethereal iodine solution (0.023 M) was added to a test tube containing 100 pL of DMDS and 100 pL of the hydrocarbon mixture.…”

Section: Septemberioctobermentioning

confidence: 99%

A REVISION OF THE NEOTROPICAL GENUS BDELYRUS HAROLD (COLEOPTERA: SCARABAEIDAE)

Cook¹

1998

Can Entomol

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The Canadian Entomologist 130: 615 -629 (1998) Relatively little information concerning the cuticular hydrocarbon composition of aquatic insects is known. The cuticular hydrocarbons of the aquatic beetle Agabus anthracinus Mannerheim have been identified with the aid of a gas chromatograph coupled to a mass spectrometer. The cuticular hydrocarbon profile comprises nalkanes (46.8%), n-alkenes (27.1%), and methylalkanes (25.9%) and is basically similar to that of terrestrial Coleoptera. However, the hydrocarbons of A. anthracinus differ in that (i) the shorter chain n-alkanes are present in higher proportion, (ii) there is a relatively lower abundance of methylalkanes, and (iii) the proportion of n-alkenes is significantly higher. Alarie, Y., H. Joly et D. Dennie. 1998. Analyse des hydrocarbures cuticulaires du coleoptkre aquatique Agabus anthracinus Mannerheim (Coleoptera : Dytiscidae). The Canadian Entomologist 130: 615-629. La composition en hydrocarbures cuticulaires des insectes aquatiques demeure inconnue. Cet expos6 identifie les hydrocarbures de la cuticule d'Agabus anthracinus Mannerheim, un colCoptkre aquatique, a l'aide d'un chromatographe en phase gazeuse coup16 a un spectromktre de masse. Les donnCes dCmontrent que la cuticule d'A. anthracinus est composCe de n-alcanes (46,8%), de n-alcknes (27,1%) et de mCthylalcanes (25,9%) ce qui est fondamentalement semblable B la condition ob-servCe parmi les col6optkres terrestres. Les hydrocarbures d'A. anthracinus se distinguent cependant (i) par une plus grand abondance de n-alcanes B chaine courte, (ii) une moins grande abondance de mCthylalcanes et (iii) un pourcentage de n-alcknes significativement ClevC. Volume 130 ~I E CANAD~AN E~TOMOLOGIST 617

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Double bond location in monounsaturated wax esters by gas chromatography/mass spectrometry of their dimethyl disulphide derivatives

Cited by 20 publications

References 17 publications

Physiological and Proteomic Adaptation of “Aromatoleum aromaticum” EbN1 to Low Growth Rates in Benzoate-Limited, Anoxic Chemostats

Physiological and Proteomic Adaptation of “Aromatoleum aromaticum” EbN1 to Low Growth Rates in Benzoate-Limited, Anoxic Chemostats

Study of the fragmentation pathways of dimethyl disulfide derivative of 2-methyl-1,4-pentadiene by GC/MS to locate the double bonds in substituted unsaturated compounds

A REVISION OF THE NEOTROPICAL GENUS BDELYRUS HAROLD (COLEOPTERA: SCARABAEIDAE)

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