QUICK SEARCH:   [advanced] Author: Keyword(s):
Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents

First published online June 6, 2005
Journal of Experimental Biology 208, 2363-2376 (2005)
Published by The Company of Biologists 2005
doi: 10.1242/jeb.01647

This Article Summary Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Pointer, M. A. Articles by Hunt, D. M. Search for Related Content PubMed PubMed Citation Articles by Pointer, M. A. Articles by Hunt, D. M.

Adaptations to an extreme environment: retinal organisation and spectral properties of photoreceptors in Antarctic notothenioid fish

Marie A. Pointer¹, Chi-Hing Christina Cheng², James K. Bowmaker¹, Juliet W. L. Parry¹, Nelyn Soto², Glen Jeffery¹, Jill A. Cowing¹ and David M. Hunt^1,*

¹ Institute of Ophthalmology, University College London, 11-43 Bath Street, London, EC1V 9EL, UK
² Department of Animal Biology, University of Illinois at Urbana-Champaign, 515 Morrill Hall, 505 S. Goodwin Avenue, Urbana, Illinois 61801, USA

View larger version (26K): [in a new window]   Fig. 1. Absorbance spectra of rods and cones. (A) Middle-wave sensitive double cones from T. bernacchii. (B) Rods from T. hansoni. (C) Short-wave sensitive single cones from T. loennbergii. Open symbols, before bleaching; filled symbols, after white light bleaching. Solid lines are visual pigment templates (Govardovskii et al., 2000) with max at 490 (A), 501 (B) and 426 nm (C). (D) Distribution histogram of rods and cones from D. mawsoni. Filled bars, rods; hatched bars, MWS single cones; open bars MWS double cones and SWS single cones; bin size 2 nm.

View larger version (50K): [in a new window]   Fig. 2. Southern hybridisation of D. mawsoni genomic DNA digested with EcoRI. The blot was probed with SWS2, Rh2 and LWS opsin probes amplified from sea bream retinal cDNA and with an SWS1 opsin probe amplified from D. mawsoni cDNA.

View larger version (40K): [in a new window]   Fig. 3. Northern blots of retinal RNA from six species of notothenioid fish. The blots were hybridised with opsin probes amplified and cloned either from sea bream opsin cDNA (SWS2, Rh2 and LWS) or from P. borchgrevinki (SWS1) cDNA.

View larger version (26K): [in a new window]   Fig. 4. SWS1 opsins. (A) Deduced amino acid sequences from six species of notothenioid fish (GenBank accession numbers AY927651-6). The Phe residue at the equivalent site to 86 in the bovine opsin sequence that is critically important for tuning into the UV is boxed, together with the counterion Glu at the equivalent site to 113 and the Lys at the equivalent site to 296 that binds the chromophore. (B) In vitro absorbance spectrum for the pigment from D. mawsoni. Recombinant SWS1 opsin was produced in transfected HEK 293T cells and the pigment regenerated with 11-cis-retinal. The difference spectrum shown with a fitted Govardovski visual pigment template, was obtained by subtracting the acid-denatured spectrum from the dark spectrum.

View larger version (21K): [in a new window]   Fig. 5. Deduced amino acid sequences for the partial sequence of SWS2 opsin from T. loennbergii (GenBank accession number AY771356), aligned with goldfish SWS2 opsin. Boxed residues identify known spectral tuning sites.

View larger version (36K): [in a new window]   Fig. 6. Rh2 opsins. (A) Deduced amino acid sequences from four species of notothenioid fish (GenBank accession numbers AY771352-AY771355). Residue 122 is boxed. (B) Neighbor-joining tree of opsin amino acid sequences. The numbers at each branch point are the bootstrap values derived from 1000 bootstraps. The scale bar is calibrated as 0.1 substitutions per site, with the length of each branch proportional to divergence. Drosophila Rh3 (GenBank accession number NM_079687) was used as an outgroup. Goldfish opsin GenBank accession numbers: Rh1 L11863, Rh2 L11866, SWS1 D85863, SWS2 11864, LWS L11867 (C) In vitro absorbance spectrum for the pigment from D. mawsoni. The difference spectrum shown with a fitted Govardovski visual pigment template, was obtained by subtracting the bleached spectrum from the dark spectrum.

View larger version (133K): [in a new window]   Fig. 7. In situ hybridisation of flat mounts of D. mawsoni retina probed with anti-sense Rh2 DIG-labelled cRNA. Note double cones with clear outer segments and labelled inner segments. Scale bar, 100 µm.

View larger version (75K): [in a new window]   Fig. 8. In situ hybridisation of en face sections of D. mawsoni retina. (A) Central retina probed with anti-sense Rh2 DIG-labelled cRNA. (B) Peripheral retina probed with anti-sense Rh2 DIG-labelled cRNA. (C) Control probed with sense Rh2 DIG-labelled cRNA. Labelled cells are indicated with arrows. Scale bar, 100 µm.

View larger version (117K): [in a new window]   Fig. 9. In situ hybridisation of transverse cryosections of D. mawsoni retina. (A) Peripheral retina with SWS2 anti-sense probe. (B) Central retina with SWS2 anti-sense probe. (C) Control peripheral retina with SWS2 sense probe. (D) Peripheral retina with Rh2 anti-sense probe. (E) Control peripheral retina with Rh2 sense probe. Positive regions are stained blue. INL, inner nuclear layer; ONL, outer nuclear layer; OS, outer segments; RPE, retinal pigmented epithelium. Scale bar, 100 µm.

View larger version (83K): [in a new window]   Fig. 10. Flat whole-mounted retinae from (A) D. mawsoni and (B) T. hansoni. S, single cones; D, double cones. Scale bar, 100 µm.