Eye-independent, light-activated chromatophore expansion (LACE) and expression of phototransduction genes in the skin of Octopus bimaculoides

Abstract

Cephalopods are renowned for changing the color and pattern of their skin for both camouflage and communication. Yet, we do not fully understand how cephalopods control the pigmented chromatophore organs in their skin and change their body pattern. Although these changes primarily rely on eyesight, we found that light causes chromatophores to expand in excised pieces of Octopus bimaculoides skin. We call this behavior light-activated chromatophore expansion (or LACE). To uncover how octopus skin senses light, we used antibodies against r-opsin phototransduction proteins to identify sensory neurons that express r-opsin in the skin. We hypothesized that octopus LACE relies on the same r-opsin phototransduction cascade found in octopus eyes. By creating an action spectrum for the latency to LACE, we found that LACE occurred most quickly in response to blue light. We fit our action spectrum data to a standard opsin curve template and estimated the λ max of LACE to be 480 nm. Consistent with our hypothesis, the maximum sensitivity of the light sensors underlying LACE closely matches the known spectral sensitivity of opsin from octopus eyes. LACE in isolated preparations suggests that octopus skin is intrinsically light sensitive and that this dispersed light sense might contribute to their unique and novel patterning abilities. Finally, our data suggest that a common molecular mechanism for light detection in eyes may have been co-opted for light sensing in octopus skin and then used for LACE.

Camouflage during movement in the European cuttlefish (Sepia officinalis)

“…Matching the brightness, texture and pattern to different backgrounds requires an advanced visual system, processing capabilities and proper skin physiology, which may include specific photoreceptors (Ramirez and Oakley, 2015). Changing colour and reflectance while chasing a prey or hiding from a predator requires the cephalopod to possess a high level of visual information processing and the control of skin chromatophores and irridophores, without interfering with the activity it is engaged in.…”

The genome and transcriptome of Japanese flounder provide insights into flatfish asymmetry

“…We determined the effect of RA (Sigma-Aldrich) on eye migration in 16,18,21,23,26,28, and 30 DAH larvae by microinjecting 50 nl into the suborbital area of the blind side: (i) no-injection control group 1 (natural development), (i) DMSO control group 2 (RA vehicle), (iii) all-trans RA group (ATRA, 2 mg/ml)), 9cRA group (9-cis-RA, 2 mg/ml), and 13cRA group (13-cis-RA, 2 mg/ml) (Supplementary Fig. 28).…”

“…In summary, we demonstrate that an RA gradient may be crucial for the generation of asymmetric pigmentation in post-metamorphic flatfish. Recently, opsins in the skin of the adult octopus have been related to eye-independent color changes 21 . During flatfish metamorphosis there was ubiquitous expression in skin of genes of the phototransduction pathway (rh1, rh2, lws, sws1, and sws2) (Fig.…”

Chameleon Devices

“…Yu et al [52] combine light sensors and thermochromic dye to adapt backgrounds. In nature, light sensing molecules are found in colour-changing cephalopod skin [31,40]. Cephalopods have also evolved special pupils [45] to sense the colour and pattern of their background.…”