Håstad Olle, Partridge Julian C, Odeen Anders
School of Biological Sciences, University of Bristol, Bristol, BS8 1UG, UK.
J Comp Physiol A Neuroethol Sens Neural Behav Physiol. 2009 Jun;195(6):585-90. doi: 10.1007/s00359-009-0433-8. Epub 2009 Mar 24.
Gulls (Laridae excluding Sternidae) appear to be the only shorebirds (Charadriiformes) that have a short wavelength sensitive type 1 (SWS1) cone pigment opsin tuned to ultraviolet (UV) instead of violet. However, the apparent UV-sensitivity has only been inferred indirectly, via the interpretation that the presence of cysteine at the key amino acid position 90 in the SWS1 opsin confers UV sensitivity. Unless the cornea and the lens efficiently transmit UV to the retina, gulls might in effect be similar to violet-sensitive birds in spectral sensitivity even if they have an ultraviolet sensitive (UVS) SWS1 visual pigment. We report that the spectral transmission of the cornea and lens of great black-backed Larus marinus and herring gulls L. argentatus allow UV-sensitivity, having a lambda(T0.5) value, 344 nm, similar to the ocular media of UV sensitive birds. By molecular sequencing of the second alpha-helical transmembrane region of the SWS1 opsin gene we could also infer that 15 herring gulls and 16 yellow-legged gulls L. michahellis, all base-pair identical, are genetically UV-sensitive.
鸥类（鸥科，不包括燕鸥科）似乎是唯一具有短波长敏感型1（SWS1）视锥色素视蛋白的滨鸟（鸻形目），该视蛋白被调谐至紫外线（UV）而非紫光。然而，这种明显的紫外线敏感性只是通过间接推断得出，即基于SWS1视蛋白中关键氨基酸位置90处存在半胱氨酸赋予紫外线敏感性这一解释。除非角膜和晶状体能有效地将紫外线传输至视网膜，否则即使鸥类拥有紫外线敏感（UVS）的SWS1视觉色素，其光谱敏感性实际上可能与对紫光敏感的鸟类相似。我们报告称，大黑背鸥Larus marinus和银鸥L. argentatus的角膜和晶状体的光谱透射率使得它们具有紫外线敏感性，其λ（T0.5）值为344纳米，与对紫外线敏感鸟类的眼介质相似。通过对SWS1视蛋白基因的第二个α - 螺旋跨膜区域进行分子测序，我们还可以推断出15只银鸥和16只黄腿鸥L. michahellis在基因上对紫外线敏感，它们的碱基对完全相同。
