15 research outputs found
Erratum to: Localization of Fatty Acyl and Double Bond Positions in Phosphatidylcholines Using a Dual Stage CID Fragmentation Coupled with Ion Mobility Mass Spectrometry.
A high content molecular fragmentation for the analysis of phosphatidylcholines (PC) was achieved utilizing a two-stage [trap (first generation fragmentation) and transfer (second generation fragmentation)] collision-induced dissociation (CID) in combination with travelling-wave ion mobility spectrometry (TWIMS). The novel aspects of this work reside in the fact that a TWIMS arrangement was used to obtain a high level structural information including location of fatty acyl substituents and double bonds for PCs in plasma, and the presence of alkali metal adduct ions such as [M + Li](+) was not required to obtain double bond positions. Elemental compositions for fragment ions were confirmed by accurate mass measurements. A very specific first generation fragment ion m/z 577 (M-phosphoryl choline) from the PC [16:0/18:1 (9Z)] was produced, which by further CID generated acylium ions containing either the fatty acyl 16:0 (C(15)H(31)CO(+), m/z 239) or 18:1 (9Z) (C(17)H(33)CO(+), m/z 265) substituent. Subsequent water loss from these acylium ions was key in producing hydrocarbon fragment ions mainly from the α-proximal position of the carbonyl group such as the hydrocarbon ion m/z 67 (+H(2)C-HC = CH-CH = CH(2)). Formation of these ions was of important significance for determining double bonds in the fatty acyl chains. In addition to this, and with the aid of (13)C labeled lyso-phosphatidylcholine (LPC) 18:1 (9Z) in the ω-position (methyl) TAP fragmentation produced the ion at m/z 57. And was proven to be derived from the α-proximal (carboxylate) or distant ω-position (methyl) in the LPC. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s13361-011-0172-2) contains supplementary material, which is available to authorized users
Identification of a component of the trail pheromone of the ant Pheidole pallidula (Hymenoptera: Formicidae)
The poison gland of minor workers of P.pallidula.Nyl. contains 3-ethyl-2,5-dimethylpyrazine which induces trail-following in other workers, but does not account for the full trail-following effect of one worker's poison gland. No pyrazines were detected in major workers and their glands do not contain the pheromone.CI:0.85FLWNAinfo:eu-repo/semantics/publishe
Gas-phase infrared spectroscopy for determination of double-bond configuration of some polyunsaturated pheromones and related compounds
Gas-phase Fourier transform infrared spectroscopy allows the determination of the geometric configuration of disubstituted carbon-carbon double bonds present in linear polyunsaturated compounds on the basis of the characteristic absorptions observed in the 3036-3011 and 982-947 cm(-1) regions. Although the 3036-3011 cm(-1) band, attributable to a =CH stretch vibration, is conventionally considered to be unreliable for cis/trans determinations, data obtained from a large number of mono- and polyunsaturated acetates show that many useful deductions can be based on this absorption, Double bonds of the RCH=CHR' type separated by at least two methylene groups, present in polyunsaturated compounds, give rise to an absorption at 3013-3011 cm(-1) if the double bonds are not proximal to a functional group or a terminal methyl group, Cis dienes whose double bonds are separated by only a single methylene group show the cis =CH stretch band at 3017 cm(-1). For methylene-interrupted polyenes, this band shows a gradual hypsochromic shift as the unsaturation increases, Furthermore, a band at 1391 cm(-1) was recognized to represent the deformation vibration of the CH2 groups located between the double bonds, The intensity of this band is proportional to the number of skipped methylene groups. I None of the isolated or methylene-interrupted dienes bearing only trans double bonds showed any significant absorptions above 3000 cm(-1). However, spectra of trans-trans conjugated compounds show a =CH stretch band at 3016-3012 cm(-1) as a well-defined shoulder on the high-frequency side of the CH2 asymmetric stretch band, in addition to the wag absorption observed at 984-982 cm(-1), which is highly characteristic for trans-trans conjugated compounds, The spectra of cis-trans or trans-cis conjugated compounds are virtually identical and show a characteristic ''fingerprint'' consisting of two bands of similar intensity at 978-976 and 949-946 cm(-1), in addition to the =C-H stretch band observed at 3021-3017 cm(-1), interestingly, not only are the spectra of conjugated cis-cis compounds devoid of any significant absorption in the 982-947 cm(-1) region, but also the =CH stretch band is broad and appears as a poorly defined shoulder on the high-frequency edge of the CH2 asymmetric stretch band
Chemical and ethological studies of the trail pheromone of the ant Manica rubida (Hymenoptera: Formicidae)
New chemicals from the dufour gland of the formicine ant Lasius niger (Hymenoptera:Formicidae)
Dufour gland secretions of workers of the ants Myrmica sulcinodis and Myrmica lobicornis, and comparison with six other species of Myrmica
Structural and chemical ontogeny of the postpharyngeal gland in the desert ant Cataglyphis niger
Aldehydic contact poisons and alarm pheromone of the ant Crematogaster scutellaris (Hymenoptera: Myrmicinae) - Enzyme-Mediated Production from acetate precursors
SCOPUS: ar.jinfo:eu-repo/semantics/publishe