Search results for "odor"
showing 10 items of 569 documents
Shining castles and humans of metal/floral appearance ? metaphorical language in the Palaiologan romances Kallimachos and Velthandros
2019
About eight centuries after Heliodorus, the Greek novel resurfaced in the twelfth century, in Komnenian Byzantium, and again two centuries later under the Palaiologan dynasty. This latter literary revival was due to the political stability of the imperial Byzantine government, which promoted cultural production, rhetorical education, and patronage networks. Kallimachos and Velthandros, two Palaiologan romances presented as court literature, combine ancient and medieval tropes with rhetorical artistry to blur the boundaries between the artificial and the natural. Castles and objects made of precious metals thus resemble living, natural spaces, and human characters are portrayed in metallurgi…
G protein-coupled odorant receptors underlie mechanosensitivity in mammalian olfactory sensory neurons
2014
Mechanosensitive cells are essential for organisms to sense the external and internal environments, and a variety of molecules have been implicated as mechanical sensors. Here we report that odorant receptors (ORs), a large family of G protein-coupled receptors, underlie the responses to both chemical and mechanical stimuli in mouse olfactory sensory neurons (OSNs). Genetic ablation of key signaling proteins in odor transduction or disruption of OR–G protein coupling eliminates mechanical responses. Curiously, OSNs expressing different OR types display significantly different responses to mechanical stimuli. Genetic swap of putatively mechanosensitive ORs abolishes or reduces mechanical res…
Effect of refrigerated storage on microbiological, chemical and sensory characteristics of a ewes’ raw milk stretched cheese
2017
This study aimed to describe the effects of refrigerated storage up to 180 days on microbiological, chemical, physical, and sensory characteristics of a PDO ewes’ raw milk stretched cheese. To this aim, a total of 224 cheeses were manufactured in four consecutive production weeks, and series of 32 of them were examined before packaging and after 15, 30, 60, 90, 120, and 180 d of storage at 4 ± 2 °C in the dark, respectively. Lactic acid bacteria cocci displayed the highest levels (7.8 Log CFU*g−1) during early storage and decreased progressively over time (7.4 Log CFU*g−1), while the opposite trend was observed for lactic acid bacteria rods (from 6.5 to 7.3 Log CFU*g−1). TMC and enterocci s…
Chemistry, microscopy and smell: bloodstains and nineteenth-century legal medicine
2015
This paper analyses the development of three methods for detecting bloodstains during the first half of the nineteenth-century in France. After dealing with the main problems in detecting bloodstains, the paper describes the chemical tests introduced in the mid-1820s. Then the first uses of the microscope in the detection of bloodstains around 1827 are discussed. The most controversial method is then examined, the smell test introduced by Jean-Pierre Barruel in 1829, and the debates which took place in French academies and learned societies during ensuing years are surveyed. Moving to the courtrooms a review is conducted of how the different methods were employed in criminal trials. By revi…
Electrochemical detection of the 2-isobutyl-3-methoxypyrazine model odorant based on odorant-binding proteins: The proof of concept
2014
Abstract We developed an electrochemical assay for the detection of odorant molecules based on a rat odorant-binding protein (rOBP3). We demonstrated that rOBP3 cavity binds 2-methyl-1,4-naphtoquinone (MNQ), an electrochemical probe, as depicted from the decrease of its electrochemical signal, and deduced the dissociation constant, Kd MNQ = 0.5(± 0.2) μM. The amount of MNQ displaced from rOBP3 by 2-isobutyl-3-methoxypyrazine (IBMP), a model odorant molecule, was measured using square-wave voltammetry. The release of MNQ by competition led to an increase of the electrochemical response. In addition, this method allowed determination of the dissociation constant of rOBP3 for IBMP, Kd IBMP =…
Nuclear magnetic resonance spectroscopic study of beta-lactoglobulin interactions with two flavor compounds, gamma-decalactone and beta-ionone.
2002
Interactions between a well-characterized protein, beta-lactoglobulin, and two flavor compounds, beta-ionone and gamma-decalactone, were studied by 2D NMR spectroscopy. NMR spectra were recorded in aqueous solution (pH 2.0, 12 mM NaCl, 10% D(2)O) under conditions such that beta-lactoglobulin is present in a monomeric state. TOCSY and NOESY spectra were recorded on the protein and the complexes between protein and ligands. The spectra of the NH-CH(alpha) region showed the cross-signals due to the coupling between N- and C-bonded protons in the polypeptide backbone. The observed chemical shift variations in the presence of ligands can be assigned to changes in the protein conformation. It app…
Structure of rat odorant-binding protein OBP1 at 1.6 angstrom resolution
2009
The nasal mucosa is a specialist interfacial region sandwiched between the olfactory system and the gaseous chemical milieu. In mammals and insects, this region is rich in odorant-binding proteins that are thought to aid olfaction by assisting mass transfer of the many different organoleptic compounds that make up the olfactory landscape. However, in mammals at least, our grasp on the exact function of odorant-binding proteins is tentative and better insight into the role of these proteins is warranted, not least because of their apparent significance in the olfactory systems of insects. Here, the crystal structure of rat odorant-binding protein 1 is reported at 1.6 Å resolution. This prote…
Proteome response of Tribolium castaneum larvae to Bacillus thuringiensis toxin producing strains.
2012
Susceptibility of Tribolium castaneum (Tc) larvae was determined against spore-crystal mixtures of five coleopteran specific and one lepidopteran specific Bacillus thuringiensis Cry toxin producing strains and those containing the structurally unrelated Cry3Ba and Cry23Aa/Cry37Aa proteins were found toxic (LC(50) values 13.53 and 6.30 µg spore-crystal mixture/µL flour disc, respectively). Using iTRAQ combined with LC-MS/MS allowed the discovery of seven novel differentially expressed proteins in early response of Tc larvae to the two active spore-crystal mixtures. Proteins showing a statistically significant change in treated larvae compared to non-intoxicated larvae fell into two major cat…
Enthalpy/entropy compensation effects from cavity desolvation underpin broad ligand binding selectivity for rat odorant binding protein 3
2014
Evolution has produced proteins with exquisite ligand binding specificity, and manipulating this effect has been the basis for much of modern rational drug design. However, there are general classes of proteins with broader ligand selectivity linked to function, the origin of which is poorly understood. The odorant binding proteins (OBPs) sequester volatile molecules for transportation to the olfactory receptors. Rat OBP3, which we characterize by X-ray crystallography and NMR, binds a homologous series of aliphatic gamma-lactones within its aromatic-rich hydrophobic pocket with remarkably little variation in affinity but extensive enthalpy/entropy compensation effects. We show that the bin…
Multivariate approach to reveal relationships between sensory perception of cheeses and aroma profile obtained with different extraction methods
2014
A new and original statistical approach was used to compare the effectiveness of 4 different methods to analyse aroma compounds of seven different commercial semi-hard cheeses with regard to their orthonasal sensory perception. Four extraction methods were evaluated: Purge and Trap, Artificial Mouth, Solid-Phase Microextraction (SPME) and Solvent-Assisted Flavour Evaporation (SAFE). Among the headspace methods, Artificial Mouth gave the closest representation of the studied product space to the sensory perception one. The SAFE method was complementary to the dynamic headspace methods, as it was very efficient in extracting the heavy molecules but less efficient for extracting the most volat…