Regulation of cytoplasmic pH in bacteria.

A novel G protein α-subunit (α-gustducin) has been identified and cloned from taste tissue, α-Gustducin messenger RNA is expressed in taste buds of all taste papillae (circumvallate, foliate and fungiform); it is not expressed in non-sensory portions of the tongue, nor is it expressed in the other tissues examined, α-Gustducin most closely resembles the transducins (the rod and cone photoreceptor G proteins), suggesting that gustducin's role in taste transduction is analogous to that of transducin in light transduction.

Gustducin is a taste-cell-specific G protein closely related to the transducins

The mechanism of the sense of smell has long been a subject for theory and speculation. More recently, the notion of odorant recognition by stereospecific protein receptors has gained wide acceptance, but the receptor molecules remained elusive. The recognition molecules are believed to be quite diverse, which would partly explain the unusual difficulties encountered in their isolation by conventional ligand-binding techniques. An alternative approach would be to probe the receptors through transductory components that may be common to all receptor types. Here we report the identification of one such transductory molecular component. This is an odorant-sensitive adenylate cyclase, present in very large concentrations in isolated dendritic membranes of olfactory sensory neurones. Odorant activation of the enzyme is ligand and tissue specific, and occurs only in the presence of GTP, suggesting the involvement of receptor(s) coupled to a guanine nucleotide binding protein (G-protein). The olfactory G-protein is independently identified by labelling with bacterial toxins, and found to be similar to stimulatory G-proteins in other systems. Our results suggest a role for cyclic nucleotides in olfactory transduction, and point to a molecular analogy between olfaction and visual, hormone and neurotransmitter reception. Most importantly, the present findings reveal new ways to identify and isolate olfactory receptor proteins.

Odorant-sensitive adenylate cyclase may mediate olfactory reception

The olfactory systems of vertebrates are able to discriminate a vast array of structurally diverse odorants. This perceptual acuity derives from a series of information-processing events that occur within distinct neural structures through which olfactory sensory information flows. This review discusses current knowledge concerning the mechanisms by which olfactory stimuli are initially detected and transduced into electrical signals that are transmitted to the olfactory bulb of the brain. It also reviews how information may initially be organized, or encoded, and then reorganized as it flows through the system.

Information Coding in the Vertebrate Olfactory System

Is the bitter rejection response always adaptive

High activity of adenyl cyclase in olfactory and gustatory organs

Mechanism of bitter taste reception: Interaction of bitter compounds with monolayers of Lipids from bovine circumvallate papillae

PLASMA membranes isolated from bovine olfactory epithelium containing large numbers of olfactory receptors cells are characterized bya high lipid, and especially phospholipid, content1. Odorant molecules are lipoid-soluble, and so this suggests that the interaction of odorant molecules with the lipid layer of the olfactory receptor membrane is important in olfactory reception. We have therefore examined the effect of various odorants on lipid monolayers from olfactory epithelium and propose a theory for the mechanism of olfactory reception.

Effect of Odorants on Lipid Monolayers from Bovine Olfactory Epithelium

Purification and properties of esterase from Bacillus stearothermophilus.

https://febs.onlinelibrary.wiley.com/doi/pdf/10.1016/0014-5793%2876%2980816-2

Noriyuki Koyama

Papers

High activity of adenyl cyclase in olfactory and gustatory organs

Mechanism of bitter taste reception: Interaction of bitter compounds with monolayers of Lipids from bovine circumvallate papillae

Effect of Odorants on Lipid Monolayers from Bovine Olfactory Epithelium

Purification and properties of esterase from Bacillus stearothermophilus.

Na+-dependent uptake of amino acids by an alkalophilic Bacillus.