| dc.contributor.author | Li, Qinglu (Chinglu). | en_US |
| dc.date.accessioned | 2014-10-21T12:38:29Z | |
| dc.date.available | 1996 | |
| dc.date.issued | 1996 | en_US |
| dc.identifier.other | AAINN16030 | en_US |
| dc.identifier.uri | http://hdl.handle.net/10222/55160 | |
| dc.description | A primary culture system for the visual system in Drosophila has been established. With this system, neurite outgrowth from intact eye imaginal discs, eye-disc fragments and dissociated eye imaginal disc cells, as well as from dissociated optic lobe cells has been obtained. Neurites express antigens to the insect neuronal marker, anti-HRP. Furthermore, immunoreactivity to antibody 24B10 indicates that neurites extending from eye-imaginal discs are axons of photoreceptors. Three culture media were tested for their ability to support the survival of, and neurite extension from, eye-disc fragments in vitro at 23$\sp\circ$C. These, with supplements, were: five parts of Schneider's Drosophila medium with four parts of basal Eagle's medium; Leibovitz's L-15 medium; and Shields and Sang's M3 modified medium (MM3). The best results was obtained with 2%FBS-MM3. Differentiation of screening pigment cells required the presence of 1$\mu$g/ml 20-hydroxyecdysone (20-HE) in the medium. Only donor animals of a particular age range gave appropriate eye-disc differentiation. Eye-discs from pupae 5h old (P+5) or older commenced ommachrome synthesis in vitro in a temporal sequence close to that found in vivo. Pigment synthesis was delayed in eye discs from younger flies. Drosopterin was not synthesized in vitro under these conditions. Eye-discs from third-instar larvae or white prepupae continued their mitotic activity, which, together with the advance of the morphogenetic furrow, is consistent with continued pattern formation in vitro. | en_US |
| dc.description | Metamorphosis of flies is initiated by a surge in the haemolymph titre of ecdysteroids. Even though all cells in the eye discs are exposed to this hormone surge, cellular differentiation is variously susceptible to it. Immunoreactivities to anti-HRP, 22C10 and 24B10 have all been detected in eye-discs cultured with (1$\mu$g/ml) or without 20-HE, suggesting that the differentiation of neuronal and photoreceptor antigens does not require 20-HE. Formation of ommochromes, corneal lenses and bristles were detected in P+5 eye-disc cultures with 1$\mu$g/ml 20-HE, but not those lacking the hormone. The differentiation of synaptotagmin, and the elongation of extending photoreceptor neurites both occurred without 20-HE. Adding hormone to the culture medium increased both the number of synaptotagmin immunoreactive spots along the length of the neurites and avenge neurite length, however. Synthesis of histamine, the photoreceptor transmitter, occurred in eye-disc cultures. Combined with the expression of synaptotagmin, this suggests that photoreceptor axons may release transmitter. Most ($>$72%) neurite outgrowth seen in cultures was from photoreceptor axons that regenerated but new ommatidial differentiation of neurites also occurred in culture. These neurites were able to form synapse-like contacts with neighbouring cells, as seen in EM. This recommends the potential for tissue culture as a system to study synaptogenesis. | en_US |
| dc.description | Thesis (Ph.D.)--Dalhousie University (Canada), 1996. | en_US |
| dc.language | eng | en_US |
| dc.publisher | Dalhousie University | en_US |
| dc.publisher | | en_US |
| dc.subject | Biology, Entomology. | en_US |
| dc.subject | Biology, Animal Physiology. | en_US |
| dc.title | Development in vitro of the visual system in Drosophila melanogaster. | en_US |
| dc.type | text | en_US |
| dc.contributor.degree | Ph.D. | en_US |
