Sensory transduction

Nultsch W, Hader D-P (1980) Light Perception and Sensory Transduction in Photosynthetic Prokaryotes. 41 111-139 Nyholm RS, see Hall DI (1973) 15 3-51... 

Berghard A. and Buck L.B. (1996). Sensory transduction in vomeronasal neurons evidence for G-alpha-o, G-alpha-i2, and adenylyl cyclase II as major components of a pheromone signaling cascade. J Neurosci 16, 909-918. 

Wu Y., Tirindelli R, and Ryba N.J. (1996). Evidence for different chemo-sensory transduction pathways signal in olfactory and vomeronasal neurons. Biochem Biophys Res Comm 220, 900-904. 

For the analysis of the primary bluelight receptor action, it is necessary to uncouple the sensory transduction process from the subsequent phototropic reaction... 

The second step of carotenogenesis, the period of protein synthesis, has clearly been separated from the sensory transduction by means of the inhibitors of protein synthesis cycloheximide12 78 142) and chloramphenical12 146 147). Regardless of their presence, light-induction was feasible, but carotenogenesis took place only after their removal. 

Assuming that flavin is the actual flavin receptor, changes in quite a number of parameters might initiate sensory transduction ... 

Scheme 3. Flavins are capable to undergo both 1 e and 2 e input/output redoxreactions as indicated. Since cytochrome b is a typical 1 e redox reagent, Hemmerich and Schmidt86) suggest a radical mechanism of the sensory transduction (assuming that the cyt b photoreduction is photo-tropically relevant). The nature and fate of the flavin-photosubstrate XH remains obsure. For the case X = cyt b the scheme represents a reversed respiration electron pathway...

As discussed throughout this article, there is strong evidence that the bluelight photoreceptor is a flavin (flavoprotein) anistropically bound to a membrane moiety. All potential sensory transduction mechanisms require such a secondary component. 

Nevertheless, there is good evidence that in all purely bluelight sensitive organisms, the photoreceptor is a flavin (flavoprotein) (Table 2), which appears to be bound to membranes (plasmalemma) in a highly dichroic manner. The mechanism of sensory transduction is probably correlated with light-induced redox reactions mediated by a flavin. This observation is consistent with the fact that nearly all physiolog-... 

Besides these shortcomings the bluelight receptor and sensory transduction problem is recently being attacked on the basis of completely artificial flavin/membrane systems. These appear to provide well-defined model systems to study anisotropic flavin (photo-) chemistry. This, in turn, is an essential prerequisite which allows the primary photo-events of physiological bluelight reception to be imitated and elucidated. 

Hemmerich, P., Schmidt, W. In Proc. of Photoreception and sensory transduction in aneural organisms , Sept. 3-14, 1979, Versilia, Italy, in press... 

Diehn, B. Photic responses and sensory transduction in motile protists, in Handbook of Sensory Physiology, (H. Autrum, ed.), pp. 24-68, Springer Berlin. 1979... 

The growth rate, however, always returns to the baseline level less than 30 min after the stimulus as shown in Fig. 7. This observation demonstrates that the model is not correct for the growth response as there must be at least two biochemical steps along the light sensory transduction chain which are subject to regulation. One sets the level of sensitivity and the other is responsible for the return of growth rate to the base-line level. Only the first step which sets the level of sensitivity obeys the simple differential equation of Delbriick and Reichardt and only then in cases where a small stimulus was employed. 

---