The role of perireceptor events in vertebrate olfaction

Pelosi, Paolo

doi:10.1007/pl00000875

Cited by 101 publications

(85 citation statements)

References 70 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Vertebrate OBPs share with lipocalins a compact structure made of eight antiparallel β-sheets and a short segment of α-helix close to the protein C terminus (15,16). Several pieces of evidence strongly suggest that, in mammals, OBPs are specific carriers for pheromones (17). The most compelling facts are their sites of production outside the olfactory mucosa in the vomeronasal organ and the nasal respiratory epithelium and the occurrence of the same or very similar OBPs in the nose and in biological glands and fluids releasing specific pheromones.…”

Section: Significancementioning

confidence: 99%

Reverse chemical ecology: Olfactory proteins from the giant panda and their interactions with putative pheromones and bamboo volatiles

Zhu

Arena

Spinelli

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

104

View full text Add to dashboard Cite

The giant panda Ailuropoda melanoleuca belongs to the family of Ursidae; however, it is not carnivorous, feeding almost exclusively on bamboo. Being equipped with a typical carnivorous digestive apparatus, the giant panda cannot get enough energy for an active life and spends most of its time digesting food or sleeping. Feeding and mating are both regulated by odors and pheromones; therefore, a better knowledge of olfaction at the molecular level can help in designing strategies for the conservation of this species. In this context, we have identified the odorant-binding protein (OBP) repertoire of the giant panda and mapped the protein expression in nasal mucus and saliva through proteomics. Four OBPs have been identified in nasal mucus, while the other two were not detected in the samples examined. In particular, AimelOBP3 is similar to a subset of OBPs reported as pheromone carriers in the urine of rodents, saliva of the boar, and seminal fluid of the rabbit. We expressed this protein, mapped its binding specificity, and determined its crystal structure. Structural data guided the design and preparation of three protein mutants bearing single-amino acid replacements in the ligand-binding pocket, for which the corresponding binding affinity spectra were measured. We also expressed AimelOBP5, which is markedly different from AimelOBP3 and complementary in its binding spectrum. By comparing our binding data with the structures of bamboo volatiles and those of typical mammalian pheromones, we formulate hypotheses on which may be the most relevant semiochemicals for the giant panda.odorant-binding proteins | chemical communication | X-ray structure | proteomics | giant panda T he giant panda Ailuropoda melanoleuca is endemic of China and was formerly classified as an endangered species, now as a vulnerable species, but its population has remained rather stable, although very low, during the last centuries (1). Its phylogenetic classification has been a matter of debate for some time, but molecular genetic studies have recently shown that this species belongs to Ursidae, of which it represents an ancestral branch together with the spectacled bears, Tremarctos, and the sloth bear (1-3). The diets of these species are different from those of carnivorous bears: the giant panda is fully herbivorous, the spectacled bears are mainly herbivorous, and sloth bears feed on termites, fruits, and vegetables. The giant panda also shares with spectacled bears and sloth bears the absence of hibernation, an important characteristic that differentiates these species from other Ursidae (4).The obligate bamboo diet of the giant panda, which is not compatible with its carnivorous digestive system, is barely sufficient to provide the energy required for an active life, likely accounting for the slow movements and long periods of rest typical of this species (5). It has been also suggested that the reduced size of the brain, liver, and kidneys of the giant panda relative to other mammals could be a measure to further reduce the use of i...

show abstract

Section: Significancementioning

confidence: 99%

Reverse chemical ecology: Olfactory proteins from the giant panda and their interactions with putative pheromones and bamboo volatiles

Zhu

Arena

Spinelli

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

104

View full text Add to dashboard Cite

show abstract

“…These proteins have been thought to play a role in transporting (Tegoni et al, 2000;Pelosi, 2001;Ko et al, 2010) or decomposing or clearing (Lazard et al, 1991;BenArie et al, 1993;Miyawaki et al, 1996;Tamura et al, 1997) external volatile odorants. Deciphering the roles of such prereceptor events occurring in the mucus would lead to a better understanding of the specificity differences of ORs in vitro and in vivo, as well as of relevant odorant recognition mechanisms.…”

Section: Introductionmentioning

confidence: 99%

Enzymatic Conversion of Odorants in Nasal Mucus Affects Olfactory Glomerular Activation Patterns and Odor Perception

Nagashima¹,

Touhara²

2010

J. Neurosci.

128

109

View full text Add to dashboard Cite

Odor information is decoded by a combination of odorant receptors, and thus transformed into discrete spatial patterns of olfactory glomerular activity. It has been found, however, that for some odorants, there are differences between the ligand specificity of an odorant receptor in vitro and its corresponding glomerulus in vivo. These observations led us to hypothesize that there exist prereceptor events that affect the local concentration of a given odorant in the nasal mucus, thus causing the apparent specificity differences. Here we show that odorants with functional groups such as aldehydes and esters are targets of metabolic enzymes secreted in the mouse mucus, resulting in their conversion to the corresponding acids and alcohols. The glomerular activation patterns elicited by an enzyme-targeted odorant in the olfactory bulb was different in the presence of an enzyme inhibitor in the mucosa, suggesting that the enzymatic conversion occurs fast enough to affect recognition of the odorant at the levels of olfactory sensory neurons. Importantly, olfactory discrimination tests revealed that mice behaviorally trained to associate an enzyme-targeted odorant to sugar rewards could not discriminate the odorant after treatment with the enzyme inhibitor. These results reveal that the enzymatic conversion of odorants in the nasal mucus appears be fast enough to affect olfactory perception, which sheds light on the previously unappreciated role of nasal mucosal enzymes in odor sensation.

show abstract

“…Any odorant molecule requires a binding carrier protein with high affinity for membrane olfactory receptor neurons (Pelosi, 2001). Guiraudie-Capraz et al (2005) used gas chromatography-mass spectrometry (GC-MS) to identify seven fatty acids (i.e., linoleic acid, palmitic acid, lauric acid, capric acid, myristic acid, palmitoleic acid, and oleic acids) in breast milk, colostrum, and amniotic fluid in pigs.…”

Section: Calming Effects Of Maternal Biological Fluidsmentioning

confidence: 99%