Soňa Vašíčková
Academy of Sciences of the Czech Republic
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Featured researches published by Soňa Vašíčková.
Journal of Chemical Ecology | 2012
Josef Cvačka; Pavel Jiroš; Blanka Kalinová; Jakub Straka; Kateřina Černá; Petr Šebesta; Aleš Tomčala; Soňa Vašíčková; Ullrich Jahn; Jan Šobotník
A female-produced sex pheromone of Stylops muelleri was identified as an unusually branched saturated aldehyde (9R)-3,5-syn-3,5,9-trimethyldodecanal. We named it stylopsal. Its structure was established by using mass spectrometry, infrared spectroscopy, and organic synthesis of candidate compounds. The synthetic standard of (9R)-3,5-syn-3,5,9-trimethyldodecanal gave identical chromatographic and mass spectrometric data as the natural pheromone and also was active in electroantennographic and behavioral assays. The female fat body lipids contained the corresponding fatty acid, indicating a possible link between lipid metabolism and the pheromone biosynthesis.
Lipids | 2008
Josef Cvačka; Edita Kofroňová; Soňa Vašíčková; Karel Stránský; Pavel Jiroš; Oldřich Hovorka; Jiří Kindl; Irena Valterová
Unusual fatty acids with 24, 26, and 28 carbon atoms were found in triacylglycerols (TAGs) isolated from fat body tissue of bumblebee Bombus pratorum. The most abundant one was (Z,Z)-9,19-hexacosadienoic acid. Its structure was determined by mass spectrometry after derivatization with dimethyl disulfide and by infrared spectroscopy. ECL (equivalent chain length) values of its methyl ester were determined on both DB-1 and DB-WAX capillary columns. (Z,Z)-9,19-Hexacosadienoic acid is quite rare in nature. So far it has been identified only in marine sponges, and this work is the first evidence of its occurrence in a terrestrial organism. HPLC/MS analysis of the bumblebee TAGs showed that (Z,Z)-9,19-hexacosadienoic acid is present in one third of all TAG molecular species. As it was found in all sn-TAG positions, it is likely that (Z,Z)-9,19-hexacosadienoic acid is transported to tissues. Interestingly, labial gland secretion of B. pratorum was found to contain (Z,Z)-7,17-pentacosadiene, a hydrocarbon with markedly similar double bond positions and geometry. Possible biosynthetic relationships between these two compounds are discussed.
Phytochemistry | 1975
Jan Vrkoč; Miloš Buděšínský; L. Dolejš; Soňa Vašíčková
Abstract Spectral data and degradations were used to determine the structure of arenophthalide A, a glycoside of the formula C19H24O9, isolated from the roots of Helichrysum arenarium. Structure I was assigned to the compound.
Naturwissenschaften | 2012
Stefan Jarau; Petr Žáček; Jan Šobotník; Vladimír Vrkoslav; Romana Hadravová; Audrey Coppée; Soňa Vašíčková; Pavel Jiroš; Irena Valterová
Among the large number of exocrine glands described in bees, the tarsal glands were thought to be the source of footprint scent marks. However, recent studies showed that the compounds used for marking by stingless bees are secreted by leg tendon instead of tarsal glands. Here, we report on the structure of leg tendon glands in males of Bombus terrestris, together with a description of the chemical composition of their secretions and respective changes of both during the males’ lives. The ultrastructure of leg tendon glands shows that the secretory cells are located in three independent regions, separated from each other by unmodified epidermal cells: in the femur, tibia, and basitarsus. Due to the common site of secretion release, the organ is considered a single secretory gland. The secretion of the leg tendon glands of B. terrestris males differs in its composition from those of workers and queens, in particular by (1) having larger proportions of compounds with longer chain lengths, which we identified as wax esters; and (2) by the lack of certain hydrocarbons (especially long chain dienes). Other differences consist in the distribution of double bond positions in the unsaturated hydrocarbons that are predominantly located at position 9 in males but distributed at seven to nine different positions in the female castes. Double bond positions may change chemical and physical properties of a molecule, which can be recognized by the insects and, thus, may serve to convey specific information. The function of male-specific compounds identified from their tendon glands remains elusive, but several possibilities are discussed.
Journal of The Chemical Society-perkin Transactions 1 | 1988
Pavel Kočovský; Ivo Starý; Jaroslav Zajicek; František Tureček; Soňa Vašíčková
Hypobromous acid addition to 3β,7β-, 3δ,7α-, 3β,7β-, and 3α,7α-diacetoxycholest-5-ene (8)–(11) and 3β,7β,19- and 3β,7α,19-triacetoxycholest-5-ene (12) and (13) involves intramolecular participation of the neighbouring acetoxy group(s). Competing reaction pathways responsible for the product distribution are discussed. The relative importance of steric, electronic (Markownikoff), and stereoelectronic effects has been elucidated. The findings may be used for prediction of the reaction outcome. They also demonstrate that the purposeful introduction of a neighbouring group can direct the addition along the desired route.
Journal of Chemical Ecology | 2007
Rafal Piskorski; Robert Hanus; Soňa Vašíčková; Josef Cvačka; Jan Šobotník; Aleš Svatoš; Irena Valterová
Collection of Czechoslovak Chemical Communications | 1987
Zdeněk Wimmer; Miloš Buděšínský; T. Macek; Aleš Svatoš; David Šaman; Soňa Vašíčková; Miroslav Romaňuk
Collection of Czechoslovak Chemical Communications | 1976
M. Streibl; Soňa Vašíčková; V. Herout; V. Bouška
Organic Geochemistry | 2009
Anton Zubrik; David Šaman; Soňa Vašíčková; Bernd R.T. Simoneit; L’udmila Turčániová; Michal Lovás; Josef Cvačka
Tetrahedron Letters | 1971
Jan Vrkoč; L. Dolejš; Petr Sedmera; Soňa Vašíčková; F. Šorm