American researchers have studied the biochemistry of protective spray bugs scorers Brachininae elongatulus, which is heated to 100 degrees Celsius, and denied the existence of a uniform starting materials for the benzoquinones. For each of benzoquinone took its precursor, while it can get into the body through the primary cavity and through food. In experiments, scientists injected beetles to deuterated metacresol and determine what he transformed into when fired. Article published in the journal The Science of Nature.
Family of ground Beetles (Carabidae) has made extensive use of chemical means of protection from external threats. Bug scorers (subfamily Brachininae and Paussinae) use them most effectively — they shoot from the abdominal glands of hot liquids (100 degrees Celsius) with typical cotton. Defense mechanisms of many species of these subfamilies has been studied, however, bugs have a kind of Key to elongatulus remained unexplored part of the defensive secret.
Scorers do not store protective liquid and mixed chemicals directly before the shot. Based on the exothermic chemical reaction is the oxidation of hydroquinone by hydrogen peroxide to benzoquinone. The benzoquinones are used not only scorers, for example, benzoquinone in his defensive system used by some arthropods (centipedes and harvestmen), cockroaches, earwigs and termites. Have Scarabaeoidea beetles (Scarabaeoidea), the benzoquinone may be used as a pheromone.
However, researchers still do not understand the process of biological synthesis of benzoquinones. There are only some hypotheses: some scientists believe the source of quinones 1,4-hydroquinone, and other aromatic amino acids (tyrosine or phenylalanine), and the recent work of biochemists showed that benzoquinones can be formed during the sequential reactions of condensation of acetates and propionates.
The Atul of Actigal (Athula B. Attygalle) with colleagues from Stevens Institute of Technology and the universities of California and Arizona suggested that the source of the 2-methyl,1,4-benzoquinone is metacresol. To confirm this hypothesis, scientists have tracked the isotopic composition of the secretion after administration of deuterated metacresol in the primary cavity beetle-scorer and after the supplements in his food. Moreover, the researchers checked out the ability to store reagents in special containers for this, they tied up the base of the tank and separated him from the reaction chamber.
Beetles of the species B. elongatulus , scientists have divided into several groups: one group was administered deuterated precursor through the primary cavity, the second group within a few weeks they were fed food with this substance. Before the experiment the beetles were frozen to reduce their activity, and then activated them with tweezers. Some scientists beetles were dissected and the abdomens were extracted substance out of the reservoir.
Using gas chromatography, the scientists determined that protective secret beetle-scorer mainly contains 2-methyl-1,4-benzoquinone and 1,4-benzoquinone, as well as a small number of their derivatives. To find out what product is obtained when injected into the primary cavity of deuterated metacresol, the researchers used a method of mass spectrometry and found that turned out to deuterated 2-methyl-1,4-benzoquinone — it confirms the possibility of using metacresol as a reagent. Moreover, beetles B. elongatulus showed the same result by simply adding deuterated metacresol in food.