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  • Adaptation mechanisms in insect eyes = Adaptacijski mehanizmi v žuželčjem očesu
    Stušek, Peter, 1944-2023 ...
    Adaptation proccsscs in insect eyes occur on several levels, but two of the most prominent are the distal and proximal adaptation levels. In the distal, dioptrical part of the eye, adaptation is ... brought about by pupillary mechanismsč however, in the proximal, photoreceptive part of eye, adaptation is based predominantly on changes in the signaling cascade efficiency and on the successful delivery of oxygen to the mitochondria. For investigations of both types of adaptation, Ascalaphus (=Libelluloides) macaronius, a specialized neuropterian, provcd successful as a suitablc model lor studying both levels of adaptation. In this animal, the retinulac of the frontal part of eye exhibit just one type of photoreceptor sensitive only to ultraviolet lightč the pupillary response, however, is also triggered by light of longer wavelengths. Thus, it suggests that the screening of light in the distal part of the eye is independent of the receptor rnechanisms in the proximal part of the eye. In addition, the pupillary response also exhibits double time-dependent dynamics and thereby a double regulation of the photon flux of both the regenerating and the adapting light. With the aid of microscope techniques (TEM, SEM, LM), it was deterrnined that there is no massive displacement of pigment granules in the secondary pigment cells of Ascalaphus during the screening process as is characteristic for a typical superposition eye. The electron micrographs indicate that the pupil appearing at the tip of crystalline cone is formed as a result of interaction between the primary and secondary pigment cells and the distal columns of the retinular cells. The imporant phase of adaptation in the proximal receptive part of the eye is the termination of receptor potential, the response of which is also an indicator of the phototransductional cascade dynamic. (Abstract truncated at 2000 characters).
    Source: Acta biologica slovenica : ABS. - ISSN 1408-3671 (Vol. 43, št. 3, 2000, str. 41-70)
    Type of material - article, component part ; adult, serious
    Publish date - 2000
    Language - english
    COBISS.SI-ID - 830031

source: Acta biologica slovenica : ABS. - ISSN 1408-3671 (Vol. 43, št. 3, 2000, str. 41-70)

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