ISSN:
1432-1351
Keywords:
Carotenoids
;
Xanthophylls
;
Rhodopsia
;
Visual pigment
;
Retinoids
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Medicine
Notes:
Summary Drosophila rearing media had only β-carotene, zeaxanthin or lutein as precursors for photopigment chromophores. Zeaxanthin and lutein are potentially optimum sources of the 3-hydroxylated retinoids of visual and accessory photopigments. Mutants made the electroretinogram in white (w) eyes selective for compound eye photoreceptors R1–6, R7 and R8: R1–6 domiantes w's electroretinogram; R7/8 generates w;ora's (ora = outer rhabdomeres absent); R8 generates w sev;- ora's (sev = sevenless). Microspectrophotometry revealed R1-6's visual pigment. In w, all 3 carotenoids yielded monotonic dose-responses for sensitivity (Fig. 4) or visual pigment (Fig. 7). An ultraviolet sensitivity peak from R1-6's sensitizing pigment was present at high but not low doses (Fig. 1). In w;ora, all 3 carotenoids gave similar spectra dominated by R7's high ultraviolet sensitivity (Fig. 2). For w sev;ora, all spectra were the shape expected for R8, peaking around 510 nm (Fig. 3). The sensitivity dose-response was at its ceiling except for low doses in w;ora (Fig. 5) and zero supplementation in w sev;ora (Fig. 6). Hence, without R1-6, most of our dose range mediated maximal visual pigment formation. In Drosophila, β-carotene, zeaxanthin and lutein mediate the formation of all major photopigments in R1-6, R7 and R8.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00192014
Permalink