Toxins perception

Fig. 12. Tentative model of the signal transduction chain that links the perception of pectic fragments to defense responses in carrot cells. Abbreviations apy, heterotrimeric G protein CaM, calmodulin 4CL, 4-coumarate-CoA ligase CTX, cholera toxin FC, fusicoccine GDP-P-S and GTP-y-S, guanosine 5 -0-(2-thiodiphosphate) and guanosine 5 -0-(3-thiotriphosphate) IP3, 1,4,5-inositol trisphosphate PAL, phenylalanine ammonia-lyase PLC, phospholipase C PR, pathogenesis related PTX, pertussis toxin Rc, receptor SP, staurosporine. Activation and inhibition are symbolized by + and -respectively.

The toxins affect the central nervous system (CNS). Symptoms start within twenty minutes and may last for two to four hours, but peak hallucinogenic activity rarely lasts for more than one hour. Symptoms include anxiety and tension, visual effects such as blurring, euphoria, increased color perception with closed eyes, but also headache and fatigue. The overall sensation is usually described as pleasant. 

G.A. Codd, Cyanobacterial toxins, the perception of water quality and the prioritization of eutrophication control, Ecol. Eng., 16 (2000) 51-60. 

Heimbeck G., Bugnon V., Gendre N., Haberlin C. and Stocker R. F. (1999) Smell and taste perception in Drosophila melanogaster larva toxin expression studies in chemosensory neurons. J. Neurosci. 19, 6599-6609. 

A characteristic of a-subunits of the Gs subfamily is that they are inhibited by cholera toxin (see Section 5.5.2). The members of the Gs subfamily are activated by hormone receptors, by odor receptors and by taste receptors. Gs-proteins mediate, e.g., signal transmission by type fl adrenaline receptors and that by glucagon receptors. During perception of taste, the taste receptors are activated, and these then pass the signal on via the olfactory G protein G0if. Perception of sweet taste is also mediated via a Gs-protein. Transmission of the signal further involves an adenylyl cyclase in all cases, the activity of which is stimulated by the Gs-proteins. 

Risks perceptible with the help of science e.g. cholera and toxins in landfill sites ... 

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