Pterins belong to an important group of compounds, acting as inhibitors, sensiziters, enzymes, coenzymes, pigments etc. and together with carotenoids and anthraquinones are responsible for characteristic coloration of bugs. This work was focused on the development of a capillary electrophoretic separation method for the analysis of six pterine derivatives, namely biopterine, neopterine, isoxanthopterine, leukopterine, xanthopterine and erythropterine and on their identification in the real samples. Separation was conducted in an uncoated fused-silica capillary termostated at 30 řC. Separation electrolyte contained boric acid, tris(hydroxymethyl)aminomethane and disodium salt of ethylenediaminetetraacetic acid. The effects of buffer pH, concentration of electrolyte components, separation voltage and wavelength of UV detection on electromigration behavior and detection sensitivity were studied. Under the optimized separation conditions, organic extracts of the three forms of Graphosoma semipunctatum bugs were analyzed.

Insects have developed many strategies of defence against predators in the course of evolution. The evolutionarily oldest and most widely used type of defence is chemical defence, followed by acoustic or optical defence. However, many species of insects use simultaneously multiple types of warning signals, which affect different sensory receptors of the given predator. Such a complex method of warning signals is called multimodal method. It may consist of a combination of simultaneous chemical and optical signals, or a combination of acoustic and optical signalling. The combination of chemical and optical signalling used against a predator is probably the most common form of multimodal signalling. The presented work deals with the analysis of biologically active substances, which participate in the defence mechanisms of a widespread species of insects - true bugs (Heteroptera). Pterin derivatives represent a large group of natural compounds derived from pteridin, bicyclic heterocycle, and they are found in virtually all living organisms from bacteria to vertebrates. In insects, they primarily serve as pigments, resulting for example in striking coloration of cuticles of Heteroptera. The first part of the dissertation was focused on identification and quantification of pterin derivatives in cuticles...