Central nervous systems of gastropods are useful to study the mechanisms of sensory processings and their related learning. Although the gastropods present their complicated behavior, their many neurons have already been identified and their neural networks are analyzed well. Here by reviewing the most advanced results in the cell physiology of olfaction, gustation, vision and their learning, we introduce a promising way for brain study in the future biophysics.
Rhodopsin absorbs light and undergoes a photobleaching. Its intermediates activate a cGMP cascade that generates a hyperpolarized potential in rod photoreceptor cells. This light-triggered cascade reaction is terminated and completely restored to the dark levels by another enzymatically controlled reaction initiated by rhodopsin phosphorylation by rhodopsin kinase. Thus, phosphorylation and dephosphorylation of rhodopsin is a crucial regulatory mechanism of photoreception of rods. I found that rhodopsin phosphorylation predominantly occurs at 334, 338 and 343 serine residues in both in vivo and in vitro. Furthermore, I also found rhodopsin phosphorylation is involved in not only the quenching phototransduction but the dark adaptation processes.
A pair of pyrene groups formed an excimer due to the arrangement in close proximity within a designed four-α-helix bundle structure. At the same position were incorporated a pair of flavin moieties. The oxidative activity wellworked against1-alkyldihydronicotinamide in the presence of surfactants.A porphyrin ring was also incorporated to a two-α-helix peptide. The conjugate formed a dimetic four-α-helix bundle structure with a face-to-face porphyrin arrangement. Incorporation of Fe (III) to the conjugate gave an artificial peroxidase. These pseudoproteins may evolve for artificial functions by adequate incorporation of various catalytic and photoreactive groups.