This study elucidates the nature of melanogenesis in B16 and Harding-Passey (HP) mouse melanomas producing melanin and melanosomes of different color and fine structure, i.e., brown-black eumelanosome-like B16 granules and reddish brown pheomelanosome-like HP granules, and compares them with "typical" 3,4-dihydroxyphenylalanine (DOPA) and sepia eumelanins and sepia eumelanosomes. The melanin co...

The existence of polarization sensitivity (PS), most likely resulting from the orthogonal arrangement of microvilli in photoreceptors, has been proposed in cephalopods for some time, although it has rarely been examined behaviourally. Here, we tested the mourning cuttlefish, Sepia plangon, and the reaper cuttlefish, Sepia mestus, for polarization sensitivity using a large-field optomotor stimul...

pharaonis phoborhodopsin (ppR; also pharaonis sensory rhodopsin II, psRII) is a receptor of the negative phototaxis of Natronobacterium pharaonis. In bacterial membrane, ppR forms a complex with its transducer pHtrII, and this complex transmits the light signal to the sensory system in the cytoplasm. In the present work, the truncated transducer, t-Htr was used which interacts with ppR [Sudo et...

The ink gland of the cuttlefish Sepia officinalis has traditionally been regarded as a convenient model system for investigating melanogenesis. This gland has been shown to contain a variety of melanogenic enzymes including tyrosinase, a dopachrome-rearranging enzyme and peroxidase. However, whether and to what extent these enzymes co-localize in the melanogenic compartments and interact is an ...

We investigated the functional trait responses to 5 nm metallic silver nanoparticle (AgNPs) exposure in the Lessepsian-entry bivalve B. pharaonis. Respiration rate (oxygen consumption), heartbeat rate, and absorption efficiency were evaluated across an 8-day exposure period in mesocosmal conditions. Basal reference values from not-exposed specimens were statistically compared with those obtaine...

We previously showed that the chimeric proteins of microbial rhodopsins, such as light-driven proton pump bacteriorhodopsin (BR) and Gloeobacter rhodopsin (GR) that contain cytoplasmic loops of bovine rhodopsin, are able to activate Gt protein upon light absorption. These facts suggest similar protein structural changes in both the light-driven proton pump and animal rhodopsin. Here we report t...

The optogenetic approach to gain control over neuronal excitability both in vitro and in vivo has emerged as a fascinating scientific tool to explore neuronal networks, but it also opens possibilities for developing novel treatment strategies for neurologic conditions. We have explored whether such an optogenetic approach using the light-driven halorhodopsin chloride pump from Natronomonas phar...