Pseudopupil
In thecompound eyeofinvertebratessuch asinsectsandcrustaceans,thepseudopupilappears as a dark spot which moves across the eye as the animal is rotated.[1]This occurs because theommatidiathat one observes "head-on" (along theiroptical axes) absorb theincident light,while those to one side reflect it.[2]The pseudopupil therefore reveals which ommatidia are aligned with the axis along which the observer is viewing.[2]
Pseudopupil analysis technique
[edit]The pseudopupil analysis technique is used to study neurodegeneration in insects likeDrosophila.An adultDrosophilaeye consists of nearly 800 unit ommatidia which are repeated in a symmetrical pattern. Each ommatidium contains 8 photoreceptor cells, each of which forms a rhabdomere (rhabdomeres 7 and 8 overlap vertically; therefore, only rhabdomere 7 is visible externally). Neurodegeneration leads to loss or degradation of photoreceptors.[3]By visualizing and counting the intact rhabdomeres, degradation level can be measured. Thus, analyzing the pseudopupil can permit empirical study of neurodegeneration.
References
[edit]- ^M. F. Land; G. Gibson; J. Horwood; J. Zeil (1999)."Fundamental differences in the optical structure of the eyes of nocturnal and diurnal mosquitoes"(PDF).Journal of Comparative Physiology A.185(1): 91–103.doi:10.1007/s003590050369.S2CID9114187.Archived fromthe original(PDF)on 2016-03-04.Retrieved2008-07-27.
- ^abJochen Zeil & Maha M. Al-Mutairi (1996)."Variations in the optical properties of the compound eyes ofUca lactea annulipes"(PDF).The Journal of Experimental Biology.199(7): 1569–1577.PMID9319471.
- ^Song, Wan; Smith, Marianne R.; Syed, Adeela; Lukacsovich, Tamas; Barbaro, Brett A.; Purcell, Judith; Bornemann, Doug J.; Burke, John; Marsh, J. Lawrence (2013).Morphometric analysis of Huntington's disease neurodegeneration in Drosophila.Methods in Molecular Biology. Vol. 1017. pp. 41–57.doi:10.1007/978-1-62703-438-8_3.ISBN978-1-62703-437-1.ISSN1940-6029.PMID23719906.
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