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1.
Adv Biol (Weinh) ; : e2400117, 2024 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-38548667

RESUMO

Increased sugar concentrations on mucosal surfaces display risk factors for infections. This study aims to clarify sugar monitoring in the urethra. Urethral tuft cells (UTC) are known sentinels monitoring the urethral lumen for potentially harmful substances and initiating protective mechanisms. Next-generation sequencing (NGS), RT-PCR, and immunohistochemistry show expression of the taste receptor Tas1R3 in murine UTC, a crucial component of the classical sweet detection pathway. Isolated UTC respond to various sugars with an increase of intracellular [Ca2+]. The Tas1R3 inhibitor gurmarin and Tas1R3 deletion reduces these responses. Utilizing mice lacking UTC, glibenclamide, a K+-ATP channel antagonist, and phlorizin, a SGLT1 inhibitor, reveal an additional Tas1R3 independent sweet detection pathway. Inhibition of both pathways abrogates the sugar responses. Rat cystometry shows that intraurethral application of sucrose and glucose increases detrusor muscle activity Tas1R3 dependently. Sugar monitoring in the urethra occurs via two distinct pathways. A Tas1R3 dependent pathway, exclusive to UTC, and a Tas1R3 independent sweet detection pathway, which can be found both in UTC and in other urethral epithelial cells.

3.
Biomedicines ; 12(1)2024 Jan 09.
Artigo em Inglês | MEDLINE | ID: mdl-38255244

RESUMO

The mucosal pellicle (MP) is a biological film protecting the oral mucosa. It is composed of bounded salivary proteins and transmembrane mucin MUC1 expressed by oral epithelial cells. Previous research indicates that MUC1 expression enhances the binding of the main salivary protein forming the MP, MUC5B. This study investigated the influence of MUC1 structure on MP formation. A TR146 cell line, which does not express MUC1 natively, was stably transfected with genes coding for three MUC1 isoforms differing in the structure of the two main extracellular domains: the VNTR domain, exhibiting a variable number of tandem repeats, and the SEA domain, maintaining the two bound subunits of MUC1. Semi-quantification of MUC1 using dot blot chemiluminescence showed comparable expression levels in all transfected cell lines. Semi-quantification of MUC5B by immunostaining after incubation with saliva revealed that MUC1 expression significantly increased MUC5B adsorption. Neither the VNTR domain nor the SEA domain was influenced MUC5B anchoring, suggesting the key role of the MUC1 N-terminal domain. AFM-IR nanospectroscopy revealed discernible shifts indicative of changes in the chemical properties at the cell surface due to the expression of the MUC1 isoform. Furthermore, the observed chemical shifts suggest the involvement of hydrophobic effects in the interaction between MUC1 and salivary proteins.

4.
Nucleic Acids Res ; 52(D1): D1370-D1379, 2024 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-37870437

RESUMO

Mammalian sense of smell is triggered by interaction between odorant molecules and a class of proteins, called olfactory receptors (ORs). These receptors, expressed at the surface of olfactory sensory neurons, encode myriad of distinct odors via a sophisticated activation pattern. However, determining the molecular recognition spectrum of ORs remains a major challenge. The Molecule to Olfactory Receptor database (M2OR, https://m2or.chemsensim.fr/) provides curated data that allows an easy exploration of the current state of the research on OR-molecule interaction. We have gathered a database of 75,050 bioassay experiments for 51 395 distinct OR-molecule pairs. Drawn from published literature and public databases, M2OR contains information about OR responses to molecules and their mixtures, receptor sequences and experimental details. Users can obtain information on the activity of a chosen molecule or a group of molecules, or search for agonists for a specific OR or a group of ORs. Advanced search allows for fine-grained queries using various metadata such as species or experimental assay system, and the database can be queried by multiple inputs via a batch search. Finally, for a given search query, users can access and download a curated aggregation of the experimental data into a binarized combinatorial code of olfaction.


Assuntos
Bases de Dados de Proteínas , Receptores Odorantes , Animais , Mamíferos/metabolismo , Odorantes , Neurônios Receptores Olfatórios/metabolismo , Receptores Odorantes/genética , Receptores Odorantes/metabolismo , Olfato
5.
Metabolites ; 13(8)2023 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-37623907

RESUMO

In the context of climate change, faba beans are an interesting alternative to animal proteins but are characterised by off-notes and bitterness that decrease consumer acceptability. However, research on pulse bitterness is often limited to soybeans and peas. This study aimed to highlight potential bitter non-volatile compounds in faba beans. First, the bitterness of flours and air-classified fractions (starch and protein) of three faba bean cultivars was evaluated by a trained panel. The fractions from the high-alkaloid cultivars and the protein fractions exhibited higher bitter intensity. Second, an untargeted metabolomic approach using ultra-high-performance liquid chromatography-diode array detector-tandem-high resolution mass spectrometry (UHPLC-DAD-HRMS) was correlated with the bitter perception of the fractions. Third, 42 tentatively identified non-volatile compounds were associated with faba bean bitterness by correlated sensory and metabolomic data. These compounds mainly belonged to different chemical classes such as alkaloids, amino acids, phenolic compounds, organic acids, and terpenoids. This research provided a better understanding of the molecules responsible for bitterness in faba beans and the impact of cultivar and air-classification on the bitter content. The bitter character of these highlighted compounds needs to be confirmed by sensory and/or cellular analyses to identify removal or masking strategies.

6.
Molecules ; 28(11)2023 May 25.
Artigo em Inglês | MEDLINE | ID: mdl-37298806

RESUMO

In the field of research on medicinal plants from the Armenian flora, the phytochemical study of two Scabiosa L. species, S. caucasica M. Bieb. and S. ochroleuca L. (Caprifoliaceae), has led to the isolation of five previously undescribed oleanolic acid glycosides from an aqueous-ethanolic extract of the roots: 3-O-α-L-rhamnopyranosyl-(1→3)-ß-D-glucopyranosyl-(1→4)-ß-D-glucopyranosyl-(1→4)-ß-D-xylopyranosyl-(1→3)-α-L-rhamnopyranosyl-(1→2)-α-L-arabinopyranosyloleanolic acid 28-O-ß-D-glucopyranosyl-(1→6)-ß-D-glucopyranosyl ester, 3-O-ß-D-xylopyranosyl-(1→2)-[α-L-rhamnopyranosyl-(1→4)]-ß-D-glucopyranosyl-(1→4)-ß-D-glucopyranosyl-(1→4)-ß-D-xylopyranosyl-(1→3)-α-L-rhamnopyranosyl-(1→2)-α-L-arabinopyranosyloleanolic acid 28-O-ß-D-glucopyranosyl-(1→6)-ß-D-glucopyranosyl ester, 3-O-ß-D-xylopyranosyl-(1→2)-[α-L-rhamnopyranosyl-(1→4)]-ß-D-glucopyranosyl-(1→4)-ß-D-glucopyranosyl-(1→4)-ß-D-xylopyranosyl-(1→3)-α-L-rhamnopyranosyl-(1→2)-α-L-arabinopyranosyloleanolic acid, 3-O-ß-D-xylopyranosyl-(1→2)-[α-L-rhamnopyranosyl-(1→4)]-ß-D-xylopyranosyl-(1→4)-ß-D-glucopyranosyl-(1→4)-ß-D-xylopyranosyl-(1→3)-α-L-rhamnopyranosyl-(1→2)-α-L-arabinopyranosyloleanolic acid 28-O-ß-D-glucopyranosyl-(1→6)-ß-D-glucopyranosyl ester, 3-O-α-L-rhamnopyranosyl-(1→4)-ß-D-glucopyranosyl-(1→4)-ß-D-glucopyranosyl-(1→4)-ß-D-xylopyranosyl-(1→3)-α-L-rhamnopyranosyl-(1→2)-α-L-arabinopyranosyloleanolic acid 28-O-ß-D-glucopyranosyl-(1→6)-ß-D-glucopyranosyl ester. Their full structural elucidation required extensive 1D and 2D NMR experiments, as well as mass spectrometry analysis. For the biological activity of the bidesmosidic saponins and the monodesmosidic saponin, their cytotoxicity on a mouse colon cancer cell line (MC-38) was evaluated.


Assuntos
Caprifoliaceae , Dipsacaceae , Ácido Oleanólico , Saponinas , Triterpenos , Animais , Camundongos , Glicosídeos/farmacologia , Glicosídeos/química , Ácido Oleanólico/farmacologia , Ácido Oleanólico/química , Saponinas/química , Caprifoliaceae/química , Triterpenos/farmacologia , Triterpenos/química
7.
Food Chem ; 426: 136548, 2023 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-37302309

RESUMO

Despite their interests, faba beans are characterised by bitterness but little is known about its compounds that activate the 25 human bitter receptors (TAS2Rs). This study aimed to determine the bitter molecules in faba beans, especially saponins and alkaloids. These molecules were quantified by UHPLC-HRMS in flour, starch and protein fractions of 3 faba bean cultivars. The fractions from the low-alkaloid cultivar and the protein fractions exhibited higher saponin content. Vicine and convicine were highly correlated with bitter perception. The bitterness of soyasaponin ßb and alkaloids was studied using a cellular approach. Soyasaponin ßb activated 11 TAS2Rs, including TAS2R42 whereas vicine activated only TAS2R16. The high vicine content should explain the faba bean bitterness considering that concentration of soyasaponin ßb was low. This research provides a better understanding of the bitter molecules in faba beans. Selection of low-alkaloid ingredients or alkaloid removal treatments could improve the faba bean flavour.


Assuntos
Alcaloides , Saponinas , Vicia faba , Humanos , Paladar
8.
Molecules ; 28(8)2023 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-37110532

RESUMO

Despite the many advantages of pulses, they are characterised by off-flavours that limit their consumption. Off-notes, bitterness and astringency contribute to negative perceptions of pulses. Several hypotheses have assumed that non-volatile compounds, including saponins, phenolic compounds, and alkaloids, are responsible for pulse bitterness and astringency. This review aims to provide an overview highlighting the non-volatile compounds identified in pulses and their bitter and/or astringent characteristics to suggest their potential involvement in pulse off-flavours. Sensorial analyses are mainly used to describe the bitterness and astringency of molecules. However, in vitro cellular assays have shown the activation of bitter taste receptors by many phenolic compounds, suggesting their potential involvement in pulse bitterness. A better knowledge of the non-volatile compounds involved in the off-flavours should enable the creation of efficient strategies to limit their impact on overall perception and increase consumer acceptability.


Assuntos
Adstringentes , Paladar , Aromatizantes/análise , Fenóis/análise
9.
Food Res Int ; 163: 112260, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-36596170

RESUMO

Faba bean (Vicia faba L. minor) has many interests but is characterised by off-notes (negative odours/aromas) due to volatile compounds that are promoted during seed processing. Little is known about the volatile compounds of faba bean and their contribution to its odour. The purpose of this study was to determine the volatile compound origins of air-classified fractions (flour (F), starch (S) and protein (P)) from 3 faba bean cultivars and identify the odour-active compounds. Firstly, the volatile content of the fractions was extracted by solvent-assisted flavour evaporation (SAFE) and analysed by gas chromatography-mass spectrometry (GC-MS). A total of 147 volatile compounds were detected and categorised into 12 chemical classes. The P fractions had many volatile compounds from free fatty acid (FFA) oxidation and a higher lipoxygenase (LOX) activity. The volatile content suggested that cultivar 1 (C1) was confronted with a biotic stress at field whereas cultivar 2 (C2), richer in molecules from amino acid (AA) degradation, was contaminated by microorganisms in the field. Secondly, 35 odour-active compounds (OACs) were identified by GC-olfactometry (GC-O) and 12 odour-classes were used to describe the faba bean odours. The P fractions had higher detection frequency (DF) than the S and F fractions. P2 had a more complex odour profile due to important FFA and AA degradation. This work provides a better understanding of the impact of cultivar and processing steps on the faba bean volatile content. Selection of pulse-based ingredients with low volatile compounds could improve their flavour and increase their consumption.


Assuntos
Odorantes , Vicia faba , Vicia faba/química , Oxirredução , Cromatografia Gasosa-Espectrometria de Massas , Olfatometria
10.
Biology (Basel) ; 11(11)2022 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-36421401

RESUMO

Drosophila melanogaster flies use their proboscis to taste and distinguish edible compounds from toxic compounds. With their proboscis, flies can detect sex pheromones at a close distance or by contact. Most of the known proteins associated with probosci's detection belong to gustatory receptor families. To extend our knowledge of the proboscis-taste proteins involved in chemo-detection, we used a proteomic approach to identify soluble proteins from Drosophila females and males. This investigation, performed with hundreds of dissected proboscises, was initiated by the chromatographic separation of tryptic peptides, followed by tandem mass spectrometry, allowing for femtomole detection sensitivity. We found 586 proteins, including enzymes, that are involved in intermediary metabolism and proteins dedicated to various functions, such as nucleic acid metabolism, ion transport, immunity, digestion, and organ development. Among 60 proteins potentially involved in chemosensory detection, we identified two odorant-binding proteins (OBPs), i.e., OBP56d (which showed much higher expression in females than in males) and OBP19d. Because OBP56d was also reported to be more highly expressed in the antennae of females, this protein can be involved in the detection of both volatile and contact male pheromone(s). Our proteomic study paves the way to better understand the complex role of Drosophila proboscis in the chemical detection of food and pheromonal compounds.

11.
Molecules ; 27(22)2022 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-36431968

RESUMO

The phytochemical study of Wisteria sinensis (Sims) DC. (Fabaceae), commonly known as the Chinese Wisteria, led to the isolation of seven oleanane-type glycosides from an aqueous-ethanolic extract of the roots. Among the seven isolated saponins, two have never been reported before: 3-O-α-L-rhamnopyranosyl-(1→2)-ß-D-glucopyranosyl-(1→2)-ß-D-glucuronopyranosyl-22-O-acetylolean-12-ene-3ß,16ß,22ß,30-tetrol, and 3-O-ß-D-xylopyranosyl-(1→2)-ß-D-glucuronopyranosylwistariasapogenol A. Based on the close structures between the saponins from W. sinensis, and the glycyrrhizin from licorice, the stimulation of the sweet taste receptor TAS1R2/TAS1R3 by these glycosides was evaluated.


Assuntos
Saponinas , Wisteria , Glicosídeos/farmacologia , Glicosídeos/química , Paladar , Saponinas/química
12.
Nutrients ; 14(19)2022 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-36235793

RESUMO

Vitamins are known to generate bitterness, which may contribute to an off-taste or aftertaste for some nutritional supplements. This negative sensation can lead to a reduction in their consumption. Little is known about the bitter taste threshold and taste sensing system for the bitter taste detection of vitamins. To better understand the mechanisms involved in bitterness perception, we combined taste receptor functional assays and sensory analysis. In humans, bitter taste detection is mediated by 25 G-protein-coupled receptors belonging to the TAS2R family. First, we studied the bitterness of thirteen vitamins using a cellular-based functional taste receptor assay. We found four vitamins that can stimulate one or more TAS2Rs. For each positive molecule-receptor combination, we tested seven increasing concentrations to determine the half-maximal effective concentration (EC50) and the cellular bitter taste threshold. Second, we measured the bitter taste detection threshold for four vitamins that exhibit a strong bitter taste using a combination of ascending series and sensory difference tests. A combination of sensory and biological data can provide useful results that explain the perception of vitamin bitterness and its real contribution to the off-taste of nutritional supplements.


Assuntos
Papilas Gustativas , Paladar , Humanos , Receptores Acoplados a Proteínas G , Limiar Gustativo , Vitamina A , Vitaminas/farmacologia
13.
Biosens Bioelectron ; 218: 114755, 2022 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-36191583

RESUMO

The transduction of odorant binding into cellular signaling by olfactory receptors (ORs) is not understood and knowing its mechanism would enable developing new pharmacology and biohybrid electronic detectors of volatile organic compounds bearing high sensitivity and selectivity. The electrical characterization of ORs in bulk experiments is subject to microscopic models and assumptions. We have directly determined the nanoscale electrical properties of ORs immobilized in a fixed orientation, and their change upon odorant binding, using electrochemical scanning tunneling microscopy (EC-STM) in near-physiological conditions. Recordings of current versus time, distance, and electrochemical potential allows determining the OR impedance parameters and their dependence with odorant binding. Our results allow validating OR structural-electrostatic models and their functional activation processes, and anticipating a novel macroscopic biosensor based on ORs.


Assuntos
Técnicas Biossensoriais , Receptores Odorantes , Compostos Orgânicos Voláteis , Ligantes , Odorantes , Receptores Odorantes/química , Compostos Orgânicos Voláteis/química
14.
Foods ; 11(19)2022 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-36230094

RESUMO

Faba bean (Vicia faba L. minor) is an emerging plant-based ingredient due to its environmental, nutritional and functional benefits. However, like other pulses, it exhibits many off-flavours that limit its consumption. Little is known about the flavour of faba beans, and previous studies have focused on volatile compounds and the overall flavour. In the present study, xanthan gum gels were formulated with crude or heated protein concentrates from three faba bean cultivars and with the addition of oil and/or salt. A trained panel analysed the sensory properties of these gels, and a consumer test was carried out to assess their acceptability. The gels formulated with crude protein concentrates exhibited bitterness and green, metallic and rancid notes that decreased consumer appreciation. The heat treatment promoted pleasant notes such as potato, cereal and haricot bean notes and attenuated the most penalising descriptors associated with off-flavours. Cultivar 2 was characterised by fewer off-flavours and should be preferred over the other cultivars for the formulation of faba bean products. This work provides information on the sensory properties of different cultivars of faba bean concentrates and information likely to help improve their acceptability in the context of the formulation of food intended for humans.

15.
Int J Mol Sci ; 23(16)2022 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-36012481

RESUMO

The human sweet taste receptor is a heterodimeric receptor composed of two distinct G-protein-coupled receptors (GPCRs), TAS1R2 and TAS1R3. The TAS1R2 and TAS1R3 subunits are members of a small family of class C GPCRs whose members share the same architecture, comprising a Venus Flytrap (VFT) module linked to the seven transmembrane domains (TMDs) by a short cysteine-rich region (CRR). The VFT module of TAS1R2 contains the primary binding site for most of the sweet-tasting compounds, including natural sugars and artificial and natural sweeteners. However, cellular assays, molecular docking and site-directed mutagenesis studies have revealed that the VFT, CRR and TMD of TAS1R3 interact with some sweeteners, including the sweet-tasting protein brazzein. The aim of this study was to better understand the contribution of TAS1R2-VFT in the binding of sweet stimuli. To achieve this, we heterologously expressed human TAS1R2-VFT (hTAS1R2-VFT) in Escherichia coli. Circular dichroism spectroscopic studies revealed that hTAS1R2-VFT was properly folded with evidence of secondary structures. Using size-exclusion chromatography coupled with light scattering, we found that hTAS1R2-VFT behaves as a monomer. Ligand binding quantified by intrinsic tryptophan fluorescence showed that hTAS1R2-VFT is capable of binding sweet stimuli with Kd values, in agreement with physiological detection. Furthermore, we investigated whether the impact of point mutations, already shown to have deleterious effects on cellular assays, could impact the ability of hTAS1R2-VFT to bind sweet ligands. As expected, the ligand affinities of hTAS1R2-VFT were drastically reduced through the introduction of single amino acid substitutions (D278A and E382A) known to abolish the response of the full-length TAS1R2/TAS1R3 receptor. This study demonstrates the feasibility of producing milligram quantities of hTAS1R2-VFT to further characterize the mechanism of binding interaction and perform structural studies.


Assuntos
Receptores Acoplados a Proteínas G , Paladar , Humanos , Ligantes , Simulação de Acoplamento Molecular , Receptores Acoplados a Proteínas G/metabolismo , Edulcorantes/farmacologia
16.
J Biol Chem ; 298(9): 102331, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-35926708

RESUMO

G protein-coupled olfactory receptors (ORs) enable us to detect innumerous odorants. They are also ectopically expressed in nonolfactory tissues and emerging as attractive drug targets. ORs can be promiscuous or highly specific, which is part of a larger mechanism for odor discrimination. Here, we demonstrate that the OR extracellular loop 2 (ECL2) plays critical roles in OR promiscuity and specificity. Using site-directed mutagenesis and molecular modeling, we constructed 3D OR models in which ECL2 forms a lid over the orthosteric pocket. We demonstrate using molecular dynamics simulations that ECL2 controls the shape and volume of the odorant-binding pocket, maintains the pocket hydrophobicity, and acts as a gatekeeper of odorant binding. Therefore, we propose the interplay between the specific orthosteric pocket and the variable, less specific ECL2 controls OR specificity and promiscuity. Furthermore, the 3D models created here enabled virtual screening of new OR agonists and antagonists, which exhibited a 70% hit rate in cell assays. Our approach can potentially be generalized to structure-based ligand screening for other G protein-coupled receptors that lack high-resolution 3D structures.


Assuntos
Odorantes , Receptores Odorantes , Olfato , Animais , Humanos , Ligantes , Camundongos , Simulação de Dinâmica Molecular , Mutagênese Sítio-Dirigida , Conformação Proteica em alfa-Hélice , Receptores Odorantes/química , Receptores Odorantes/genética , Olfato/fisiologia
17.
Sci Rep ; 12(1): 9440, 2022 06 08.
Artigo em Inglês | MEDLINE | ID: mdl-35676403

RESUMO

In the gut ecosystem, microorganisms regulate group behaviour and interplay with the host via a molecular system called quorum sensing (QS). The QS molecule 3-oxo-C12:2-HSL, first identified in human gut microbiota, exerts anti-inflammatory effects and could play a role in inflammatory bowel diseases where dysbiosis has been described. Our aim was to identify which signalling pathways are involved in this effect. We observed that 3-oxo-C12:2-HSL decreases expression of pro-inflammatory cytokines such as Interleukine-1ß (- 35%) and Tumor Necrosis Factor-α (TNFα) (- 40%) by stimulated immune RAW264.7 cells and decreased TNF secretion by stimulated PBMC in a dose-dependent manner, between 25 to 100 µM. Transcriptomic analysis of RAW264.7 cells exposed to 3-oxo-C12:2-HSL, in a pro-inflammatory context, highlighted JAK-STAT, NF-κB and TFN signalling pathways and we confirmed that 3-oxo-C12:2-HSL inhibited JAK1 and STAT1 phosphorylation. We also showed through a screening assay that 3-oxo-C12:2-HSL interacted with several human bitter taste receptors. Its anti-inflammatory effect involved TAS2R38 as shown by pharmacologic inhibition and led to an increase in intracellular calcium levels. We thus unravelled the involvement of several cellular pathways in the anti-inflammatory effects exerted by the QS molecule 3-oxo-C12:2-HSL.


Assuntos
Microbioma Gastrointestinal , Percepção de Quorum , 4-Butirolactona/metabolismo , Anti-Inflamatórios/metabolismo , Ecossistema , Homosserina/metabolismo , Humanos , Leucócitos Mononucleares/metabolismo , Pseudomonas aeruginosa/fisiologia , Paladar
18.
Front Cell Dev Biol ; 10: 864599, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35433704

RESUMO

Plasmalogens are a specific glycerophospholipid subtype characterized by a vinyl-ether bound at their sn-1 moiety. Their biosynthesis is initiated in the peroxisome by dihydroxyacetone phosphate-acyltransferase (DHAPAT), which is encoded by the DAPAT gene. Previous studies have shown that plasmalogen-deficient mice exhibit major physiological dysfunctions including several eye defects, among which abnormal vascular development of the retina and a reactive activation of macroglial Müller cells. Interestingly, plasmalogen deficiency in mice is also associated with a reduced expression of brain connexin 43 (Cx43). Cx43 is the main connexin subtype of retinal glial cells and is involved in several cellular mechanisms such as calcium-based gap junction intercellular communication (GJIC) or cell migration. Thus, the aim of our work was 1) to confirm the alteration of Cx43 expression in the retina of plasmalogen-deficient DAPAT-/- mice and 2) to investigate whether plasmalogens are involved in crucial functions of Müller cells such as GJIC and cell migration. First, we found that plasmalogen deficiency was associated with a significant reduction of Cx43 expression in the retina of DAPAT-/- mice in vivo. Secondly, using a siRNA targeting DHAPAT in vitro, we found that a 50%-reduction of Müller cells content in plasmalogens was sufficient to significantly downregulate Cx43 expression, while increasing its phosphorylation. Furthermore, plasmalogen-depleted Müller cells exhibited several alterations in ATP-induced GJIC, such as calcium waves of higher amplitude that propagated slower to neighboring cells, including astrocytes. Finally, in vitro plasmalogen depletion was also associated with a significant downregulation of Müller cells migration. Taken together, these data confirm that plasmalogens are critical for the regulation of Cx43 expression and for characteristics of retinal Müller glial cells such as GJIC and cell migration.

19.
Biology (Basel) ; 12(1)2022 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-36671695

RESUMO

Odorant-binding proteins (OBPs) are abundant soluble proteins secreted in the nasal mucus of a variety of species that are believed to be involved in the transport of odorants toward olfactory receptors. In this study, we report the functional characterization of mouse OBP5 (mOBP5). mOBP5 was recombinantly expressed as a hexahistidine-tagged protein in bacteria and purified using metal affinity chromatography. The oligomeric state and secondary structure composition of mOBP5 were investigated using gel filtration and circular dichroism spectroscopy. Fluorescent experiments revealed that mOBP5 interacts with the fluorescent probe N-phenyl naphthylamine (NPN) with micromolar affinity. Competitive binding experiments with 40 odorants indicated that mOBP5 binds a restricted number of odorants with good affinity. Isothermal titration calorimetry (ITC) confirmed that mOBP5 binds these compounds with association constants in the low micromolar range. Finally, protein homology modeling and molecular docking analysis indicated the amino acid residues of mOBP5 that determine its binding properties.

20.
Foods ; 10(12)2021 Dec 18.
Artigo em Inglês | MEDLINE | ID: mdl-34945691

RESUMO

The worldwide demand for pulse-based products is increasing in the face of climate change, but their acceptability is limited due to the presence of off-flavours. Off-notes contribute to negative perceptions of pulses (beany notes). Volatile compounds belong to a large variety of chemical classes. They are mainly produced from the oxidation of unsaturated free fatty acids and the degradation of amino acids during seed development, storage, and transformation (dehulling, milling, and starch or protein production). This review aims to provide an overview highlighting the identification of these molecules in different pulses, their potential origins, and their impact on perceptions. However, data on odour-active compounds in pulses are sparse, as they are limited to those of two studies on peas and lupins. A better knowledge of the volatile compounds involved in the off-notes and their origins should allow for drawing efficient strategies to limit their impact on overall perception for more acceptable healthy food design.

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