CRESCITELLI F
J Gen Physiol. 1956 Nov 20;40(2):217-31. doi: 10.1085/jgp.40.2.217.
Retinal extracts of the Australian gecko, Phyllurus milii (White), have revealed the presence of a photosensitive pigment, unusual for terrestrial animals, because of its absorption maximum at 524 mmicro. This pigment has an absorption spectrum which is identical in form with that of other visual chromoproteins. It is not a porphyropsin, for bleaching revealed the presence, not of retinene(2), but of retinene(1) as a chromophore. Photolabile pigments with characteristics similar to those of the Phyllurus visual pigment were also detected in retinal extracts of six other species of nocturnal geckos. The presence of this retinal chromoprotein adequately accounts for the unusual visual sensitivity curve described by Denton for the nocturnal gecko. This pigment may have special biological significance in terms of the unique phylogenetic position of geckos as living representatives of nocturnal animals which retain some of the characteristics of their diurnal ancestors. The occurrence of this retinene(1) pigment, intermediate in spectral position between rhodopsin and iodopsin, is interpreted in support of the transmutation theory of Walls. The results and interpretation of this investigation point up the fact that, from a phylogenetic point of view, too great an emphasis on the duplicity theory may serve to detract attention from the evolutionary history of the retina and the essential unitarianism of the visual cells.
澳大利亚壁虎（Phyllurus milii (White)）的视网膜提取物显示存在一种光敏色素，这对陆生动物来说很不寻常，因为其最大吸收波长在524纳米。这种色素的吸收光谱在形式上与其他视觉色素蛋白的吸收光谱相同。它不是视紫蓝质，因为漂白后显示发色团不是视黄醛（2），而是视黄醛（1）。在其他六种夜行性壁虎的视网膜提取物中也检测到了具有与Phyllurus视觉色素相似特征的光不稳定色素。这种视网膜色素蛋白的存在充分解释了丹顿所描述的夜行性壁虎异常的视觉敏感度曲线。就壁虎作为夜行性动物的现存代表所具有的独特系统发育地位而言，这种色素可能具有特殊的生物学意义，它们保留了一些昼行性祖先的特征。这种视黄醛（1）色素的出现，其光谱位置介于视紫红质和视紫质之间，被解释为支持沃尔斯的转化理论。这项研究的结果和解释指出了这样一个事实，即从系统发育的角度来看，过于强调二元论可能会分散对视网膜进化历史和视觉细胞基本一元论的关注。
