title: Molecular Mechanism of the Two-Component Suicidal Weapon of Neocapritermes taracua Old Workers.
abstract: In termites, as in many social insects, some individuals specialize in colony defense, developing diverse weaponry. As workers of the termite Neocapritermes taracua (Termitidae: Termitinae) age, their efficiency to perform general tasks decreases, while they accumulate defensive secretions and increase their readiness to fight. This defensive mechanism involves self-sacrifice through body rupture during which an enzyme, stored as blue crystals in dorsal pouches, converts precursors produced by the labial glands into highly toxic compounds. Here, we identify both components of this activated defense system and describe the molecular basis responsible for the toxicity of N. taracua worker autothysis. The blue crystals are formed almost exclusively by a specific protein named BP76. By matching N. taracua transcriptome databases with amino acid sequences, we identified BP76 to be a laccase. Following autothysis, the series of hydroquinone precursors produced by labial glands get mixed with BP76, resulting in the conversion of relatively harmless hydroquinones into toxic benzoquinone analogues. Neocapritermes taracua workers therefore rely on a two-component activated defense system, consisting of two separately stored secretions that can react only after suicidal body rupture, which produces a sticky and toxic cocktail harmful to opponents.
authors.affiliation: School of Biological Sciences, University of Sydney, Sydney, NSW, Australia Faculty of Forestry and Wood Sciences, Czech University of Life Sciences, Prague, Czech Republic thomas.bourgui@gmail.com sobotnik@fld.czu.cz.
authors.forename: Thomas
authors.initials: T
authors.lastname: Bourguignon
authors.affiliation: Faculty of Forestry and Wood Sciences, Czech University of Life Sciences, Prague, Czech Republic thomas.bourgui@gmail.com sobotnik@fld.czu.cz.
authors.forename: Jan
authors.initials: J
authors.lastname: Šobotník
authors.affiliation: Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
authors.forename: Jana
authors.initials: J
authors.lastname: Brabcová
authors.affiliation: Institute of Research for Development-Sorbonne Universités, iEES-Paris, Bondy, France University Paris 13-Sorbonne Paris Cité, LEEC, Villetaneuse, France.
authors.forename: David
authors.initials: D
authors.lastname: Sillam-Dussès
authors.affiliation: Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
authors.forename: Aleš
authors.initials: A
authors.lastname: Buček
authors.affiliation: Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
authors.forename: Jana
authors.initials: J
authors.lastname: Krasulová
authors.affiliation: Faculty of Forestry and Wood Sciences, Czech University of Life Sciences, Prague, Czech Republic.
authors.forename: Blahoslava
authors.initials: B
authors.lastname: Vytisková
authors.affiliation: IMP-the Research Institute of Molecular Pathology, Vienna, Austria.
authors.forename: Zuzana
authors.initials: Z
authors.lastname: Demianová
authors.affiliation: Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
authors.forename: Michael
authors.initials: M
authors.lastname: Mareš
authors.affiliation: Evolutionary Biology and Ecology, Université Libre de Bruxelles (ULB), Brussels, Belgium.
authors.forename: Yves
authors.initials: Y
authors.lastname: Roisin
authors.affiliation: Department of Entomology, Max Planck Institute for Chemical Ecology, Jena, Germany thomas.bourgui@gmail.com sobotnik@fld.czu.cz.
authors.forename: Heiko
authors.initials: H
authors.lastname: Vogel
mesh_terms: D000818:Animals; D016000:Cluster Analysis; D004789:Enzyme Activation; D015870:Gene Expression; D020869:Gene Expression Profiling; D019476:Insect Proteins / Q000235:genetics* / Q000378:metabolism; D020049:Isoptera / Q000235:genetics* / Q000378:metabolism; D042845:Laccase / Q000235:genetics / Q000378:metabolism; D010802:Phylogeny; D013379:Substrate Specificity; D059467:Transcriptome
chemical_list: D019476:Insect Proteins; D042845:Laccase
keywords: Isoptera; altruism; colony defense; laccase; termite