title: The detection and mapping of the spatial distribution of insect defense compounds by desorption atmospheric pressure photoionization Orbitrap mass spectrometry.
abstract: Many insects use chemicals synthesized in exocrine glands and stored in reservoirs to protect themselves. Two chemically defended insects were used as models for the development of a new rapid analytical method based on desorption atmospheric pressure photoionization-mass spectrometry (DAPPI-MS). The distribution of defensive chemicals on the insect body surface was studied. Since these chemicals are predominantly nonpolar, DAPPI was a suitable analytical method. Repeatability of DAPPI-MS signals and effects related to non-planarity and roughness of samples were investigated using acrylic sheets uniformly covered with an analyte. After that, analytical figures of merit of the technique were determined. The spatial distribution of (E)-1-nitropentadec-1-ene, a toxic nitro compound synthesized by soldiers of the termite Prorhinotermes simplex, was investigated. Then, the spatial distribution of the unsaturated aldehydes (E)-hex-2-enal, (E)-4-oxohex-2-enal, (E)-oct-2-enal, (E,E)-deca-2,4-dienal and (E)-dec-2-enal was monitored in the stink bug Graphosoma lineatum. Chemicals present on the body surface were scanned along the median line of the insect from the head to the abdomen and vice versa, employing either the MS or MS(2) mode. In this fast and simple way, the opening of the frontal gland on the frons of termite soldiers and the position of the frontal gland reservoir, extending deep into the abdominal cavity, were localized. In the stink bug, the opening of the metathoracic scent glands (ostiole) on the ventral side of the thorax as well as the gland reservoir in the median position under the ventral surface of the anterior abdomen were detected and localized. The developed method has future prospects in routine laboratory use in life sciences.
authors: Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, 166 10 Prague 6, Czech Republic; Department of Analytical Chemistry, Faculty of Science, Charles University in Prague, 128 43 Prague 2, Czech Republic.
authors: Jan
authors: J
authors: Rejšek
authors: Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, 166 10 Prague 6, Czech Republic.
authors: Vladimír
authors: V
authors: Vrkoslav
authors: Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, 166 10 Prague 6, Czech Republic.
authors: Robert
authors: R
authors: Hanus
authors: Division of Pharmaceutical Chemistry and Technology, Faculty of Pharmacy, University of Helsinki, P.O. Box 56, 00014 Helsinki, Finland.
authors: Anu
authors: A
authors: Vaikkinen
authors: Division of Pharmaceutical Chemistry and Technology, Faculty of Pharmacy, University of Helsinki, P.O. Box 56, 00014 Helsinki, Finland.
authors: Markus
authors: M
authors: Haapala
authors: Division of Pharmaceutical Chemistry and Technology, Faculty of Pharmacy, University of Helsinki, P.O. Box 56, 00014 Helsinki, Finland.
authors: Tiina J
authors: TJ
authors: Kauppila
authors: Division of Pharmaceutical Chemistry and Technology, Faculty of Pharmacy, University of Helsinki, P.O. Box 56, 00014 Helsinki, Finland.
authors: Risto
authors: R
authors: Kostiainen
authors: Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, 166 10 Prague 6, Czech Republic. Electronic address: cvacka@uochb.cas.cz.
authors: Josef
authors: J
authors: Cvačka
mesh_terms: D000447:Aldehydes / Q000032:analysis*; D000818:Animals; D001274:Atmospheric Pressure; D004867:Equipment Design; D020062:Heteroptera / Q000033:anatomy & histology / Q000737:chemistry*; D020049:Isoptera / Q000033:anatomy & histology / Q000737:chemistry*; D013058:Mass Spectrometry / Q000295:instrumentation*; D009574:Nitro Compounds / Q000032:analysis*
chemical_list: D000447:Aldehydes; D009574:Nitro Compounds
keywords: Ambient mass spectrometry; Desorption atmospheric pressure photoionization; Exocrine glands; Insect chemical defense; Stink bug; Termite