Glycoconjugate-Specific Developmental Changes in the Horse Vomeronasal Organ.

The vomeronasal organ (VNO) is a tubular pheromone-sensing organ in which the lumen is covered with sensory and non-sensory epithelia. This study used immunohistochemistry and lectin histochemistry techniques to evaluate developmental changes, specifically of the glycoconjugate profile, in the horse VNO epithelium. Immunostaining analysis revealed PGP9.5 expression in some vomeronasal non-sensory epithelium (VNSE) cells and in the vomeronasal receptor cells of the vomeronasal sensory epithelium (VSE) in fetuses, young foals, and adult horses. Olfactory marker protein expression was exclusively localized in receptor cells of the VSE in fetuses, young foals, and adult horses and absent in VNSE. To identify the glycoconjugate type, lectin histochemistry was performed using 21 lectins. Semi-quantitative analysis revealed that the intensities of glycoconjugates labeled with WGA, DSL, LEL, and RCA120 were significantly higher in adult horse VSE than those in foal VSE, whereas the intensities of glycoconjugates labeled with LCA and PSA were significantly lower in adult horse VSE. The intensities of glycoconjugates labeled with s-WGA, WGA, BSL-II, DSL, LEL, STL, ConA, LCA, PSA, DBA, SBA, SJA, RCA120, jacalin, and ECL were significantly higher in adult horse VNSE than those in foal VNSE, whereas the intensity of glycoconjugates labeled with UEA-I was lower in adult horse VNSE. Histochemical analysis of each lectin revealed that various glycoconjugates in the VSE were present in the receptor, supporting, and basal cells of foals and adult horses. A similar pattern of lectin histochemistry was also observed in the VNSE of foals and adult horses. In conclusion, these results suggest that there is an increase in the level of N-acetylglucosamine (labeled by WGA, DSL, LEL) and galactose (labeled by RCA120) in horse VSE during postnatal development, implying that they may influence the function of VNO in adult horses.

Evaluation of Spinning Cone Column Distillation as a Strategy for Remediation of Smoke Taint in Juice and Wine.

Where vineyard exposure to bushfire smoke cannot be avoided or prevented, grape and wine producers need strategies to transform smoke-affected juice and wine into saleable product. This study evaluated the potential for spinning cone column (SCC) distillation to be used for the remediation of 'smoke taint'. Compositional analysis of 'stripped wine' and condensate collected during SCC treatment of two smoke-tainted red wines indicated limited, if any, removal of volatile phenols, while their non-volatile glycoconjugates were concentrated due to water and ethanol removal. Together with the removal of desirable volatile aroma compounds, this enhanced the perception of smoke-related sensory attributes; i.e., smoke taint intensified. Stripped wines also became increasingly sour and salty as ethanol (and water) were progressively removed. A preliminary juice remediation trial yielded more promising results. While clarification, heating, evaporation, deionization and fermentation processes applied to smoke-tainted white juice gave ≤3 µg/L changes in volatile phenol concentrations, SCC distillation of smoke-tainted red juice increased the volatile phenol content of condensate (in some cases by 3- to 4-fold). Deionization of the resulting condensate removed 75 µg/L of volatile phenols, but fermentation of reconstituted juice increased volatile phenol concentrations again, presumably due to yeast metabolism of glycoconjugate precursors. Research findings suggest SCC distillation alone cannot remediate smoke taint, but used in combination with adsorbents, SCC may offer a novel remediation strategy, especially for tainted juice.

Metabolic labeling of glycans with isotopic glucose for quantitative glycomics in yeast.

Changes in glycan levels could directly affect the biochemical properties of glycoproteins and thus influence their physiological functions. In order to decode the correlation of glycan prevalence with their physiological contribution, many mass spectrometry (MS) and stable isotope labeling-based methods have been developed for the relative quantification of glycans. In this study, we expand the quantitative glycomic toolbox with the addition of optimized Metabolic Isotope Labeling of Polysaccharides with Isotopic Glucose (MILPIG) approach in baker's yeast (Saccharomyces cerevisiae). We demonstrate that culturing baker's yeast in the presence of carbon-13 labeled glucose (1-13C1) leads to effective incorporation of carbon-13 to both N-linked and O-linked glycans. We established that metabolic incorporation of isotope-labeled glucose at a concentration of 5 mg/mL for three days is required for an accurate quantitative analysis with optimal isotopic cluster distribution of glycans. To validate the robustness of the method, we performed the analysis by 1:1 mixing of normal and isotope-labeled glycans, and obtained excellent linear calibration curves from various analytes. Finally, we quantitated the inhibitory effect of tunicamycin, a N-linked glycosylation inhibitor, to glycan expression profile in yeast.

Determination of glycosylation degree for glycoconjugate vaccines using a solid-phase extraction combined with liquid chromatography and tandem mass spectrometry method.

In this study, a solid-phase extraction with liquid chromatography and tandem mass spectrometry method was developed to determine the degree of glycosylation of glycosylation sites and the ratio of free carrier protein to total carrier protein for glycoconjugate vaccines. To remove and enrich the glycosylated peptides, a solid-phase extraction method was developed, optimized, and hyphenated to liquid chromatography-tandem mass spectrometry. The developed solid-phase extraction with liquid chromatography-tandem mass spectrometry method was shown to possess a wide linear dynamic range (0.03-100 µg/mL), a high sensitivity (0.03 µg/mL for CRM197), good interday and intra-day precision (relative standard deviation of peak area < 3.3%), and good recoveries from vaccine matrix (90-105%). Finally, the method was utilized to determine the degree of glycosylation and free carrier protein to total carrier protein ratio for pneumococcal conjugate vaccines and meningococcal vaccines. For quality evaluation of glycoconjugate vaccines, the method could provide more information than the traditional size exclusion chromatography method. Fourteen and twelve reported glycosylation sites for CRM197- and tetanus toxin-based vaccines can be detected, respectively.

Uptake and Glycosylation of Smoke-Derived Volatile Phenols by Cabernet Sauvignon Grapes and Their Subsequent Fate during Winemaking.

Wine made from grapes exposed to bushfire smoke can exhibit unpleasant smoky, ashy characters, which have been attributed to the presence of smoke-derived volatile phenols, in free or glycosylated forms. Here we report the uptake and glycosylation of volatile phenols by grapes following exposure of Cabernet Sauvignon vines to smoke, and their fate during winemaking. A significant delay was observed in the conversion of volatile phenols to their corresponding glycoconjugates, which suggests sequestration, the presence of intermediates within the glycosylation pathway and/or other volatile phenol storage forms. This finding has implications for industry in terms of detecting smoke-affected grapes following vineyard smoke exposure. The potential for an in-canopy sprinkler system to mitigate the uptake of smoke-derived volatile phenols by grapes, by spraying grapevines with water during smoke exposure, was also evaluated. While "misting" appeared to partially mitigate the uptake of volatile phenols by grapes during grapevine exposure to smoke, it did not readily influence the concentration of volatile phenols or the sensory perception of smoke taint in wine. Commercial sensors were used to monitor the concentration of smoke particulate matter (PM) during grapevine exposure to low and high density smoke. Similar PM profiles were observed, irrespective of smoke density, such that PM concentrations did not reflect the extent of smoke exposure by grapes or risk of taint in wine. The sensors could nevertheless be used to monitor the presence of smoke in vineyards during bushfires, and hence, the need for compositional analysis of grapes to quantify smoke taint marker compounds.

Fluorescent visual quantitation of cell-secreted sialoglycoconjugates by chemoselective recognition and hybridization chain reaction.

Sialic acid (SA), usually located at the termini of glycan chains, is one of the most important monosaccharide blocks for glycosylation of proteins. The expression level of sialoglycoconjugates (SiaGCs) in cellular secretome is of great significance in diagnosis of tumor malignancy. This work developed a fluorescent visual method for the detection of SiaGCs secreted from living cells by a boronic acid modified chip based chemoselective recognition and hybridization chain reaction. The cell-secreted SiaGCs, which were labeled with the azide group through a metabolic labeling technique during cell culture, were captured by the chip through chemoselective recognition of boronic acid toward SA. After further conjugating the azide group with an alkyne modified DNA probe, the captured SiaGCs could be conveniently endowed with the amplified fluorescent signal through a hybridization chain reaction of a pair of dye-labeled DNA hairpins, which led to a quantitative imaging method for detection of SiaGCs. The average amount of metabolically labeled SiaGCs secreted from a single HeLa cell and MCF-7 cell was 2.18 × 10-17 and 3.98 × 10-17 mol, respectively. The proposed method could be utilized to monitor the variation of the secreted SiaGCs during drug treatment, providing a useful tool for investigating the glycosylation and glycan-related biological processes.

Glycans in the roles of parasitological diagnosis and host-parasite interplay.

The investigation of the glycan repertoire of several organisms has revealed a wide variation in terms of structures and abundance of glycan moieties. Among the parasites, it is possible to observe different sets of glycoconjugates across taxa and developmental stages within a species. The presence of distinct glycoconjugates throughout the life cycle of a parasite could relate to the ability of that organism to adapt and survive in different hosts and environments. Carbohydrates on the surface, and in excretory-secretory products of parasites, play essential roles in host-parasite interactions. Carbohydrate portions of complex molecules of parasites stimulate and modulate host immune responses, mainly through interactions with specific receptors on the surface of dendritic cells, leading to the generation of a pattern of response that may benefit parasite survival. Available data reviewed here also show the frequent aspect of parasite immunomodulation of mammalian responses through specific glycan interactions, which ultimately makes these molecules promising in the fields of diagnostics and vaccinology.

Overcharging Effect in Electrospray Ionization Mass Spectra of Daunomycin-Tuftsin Bioconjugates.

Peptide-based small molecule drug conjugates for targeted tumor therapy are currently in the focus of intensive research. Anthracyclines, like daunomycin, are commonly used anticancer drug molecules and are also often applied in peptide-drug conjugates. However, lability of the O-glycosidic bond during electrospray ionization mass spectrometric analysis hinders the analytical characterization of the constructs. "Overprotonation" can occur if daunomycin is linked to positively charged peptide carriers, like tuftsin derivatives. In these molecules, the high number of positive charges enhances the in-source fragmentation significantly, leading to complex mass spectra composed of mainly fragment ions. Therefore, we investigated different novel tuftsin-daunomycin conjugates to find an appropriate condition for mass spectrometric detection. Our results showed that shifting the charge states to lower charges helped to keep ions intact. In this way, a clear spectrum could be obtained containing intact protonated molecules only. Shifting of the protonation states to lower charges could be achieved with the use of appropriate neutral volatile buffers and with tuning the ion source parameters.

Laser Cleavable Probes-Based Cell Surface Engineering for in Situ Sialoglycoconjugates Profiling by Laser Desorption/Ionization Mass Spectrometry.

Cell-surface sialoglycoconjugates (sialoglycoproteins and sialoglycolipids) play important roles in cell-cell interactions and related tumor metastasis process. Although there have been some analytical methods to evaluate the sialoglycoconjugates, an effective method providing both qualitative and quantitative information is still deficient. Here we establish an extraction-free, sensitive, and high-throughput platform to realize in situ detection of the cell-surface sialoglycoconjugates on various cell lines, e.g., cancer and normal cells by laser desorption/ionization mass spectrometry (LDI MS). In this proposal, azide groups were introduced into the ends of cell-surface sialoglycoconjugates by the biorthogonal method, and then the sialoglycoconjugates were armed with a laser-cleavable probe (Tphsene) through click chemistry. We can easily get the probes signal under laser irradiation, which reflected the presence of cell-surface sialoglycoconjugates. Different cell lines were discriminated simultaneously, and the LDI relative quantification agreed with fluorescent results. Besides, a linear quantitation relationship in the range of 100 fmol to 100 pmol was obtained with a designed and synthesized internal standard (phTsane) added. A detection limit of 5 fmol was obtained with good reproducibility. Based on the quantitative and high-throughput ability, we conducted pharmacodynamics study of drug (tunicamycin) on cancer cells. In addition, we found the tag was safe from sweet-spot effect of matrix adding. The simultaneous detection of sialoglycoconjugates and metabolites was therefore achieved. We believe that this laser cleavable probes-based cell-surface engineering for sialoglycoconjugates platform means great significance to diagnosis, prognosis, and therapeutic purposes. Besides, this strategy can be applied to other glycoconjugates which is hard to detect and the related disease processes when more corresponding chemically modified sugar substrates and exact biorthogonal reactions are developed.

Improving Analytical Characterization of Glycoconjugate Vaccines through Combined High-Resolution MS and NMR: Application to Neisseria meningitidis Serogroup B Oligosaccharide-Peptide Glycoconjugates.

Conjugate vaccines are highly heterogeneous in terms of glycosylation sites and linked oligosaccharide length. Therefore, the characterization of conjugate vaccines' glycosylation state is challenging. However, improved product characterization can lead to enhancements in product control and product quality. Here, we present a synergistic combination of high-resolution mass spectrometry (MS) and nuclear magnetic resonance spectroscopy (NMR) for the analysis of glycoconjugates. We use the power of this strategy to characterize model polysaccharide conjugates and to demonstrate a detailed level of glycoproteomic analysis. These are first steps on model compounds that will help untangle the details of complex product characterization in conjugate vaccines. Ultimately, this strategy can be applied to enhance the characterization of polysaccharide conjugate vaccines. In this study, we lay the groundwork for the analysis of conjugate vaccines. To begin this effort, oligosaccharide-peptide conjugates were synthesized by periodate oxidation of an oligosaccharide of a defined length, α,2-8 sialic acid trimer, followed by a reductive amination, and linking the trimer to an immunogenic peptide from tetanus toxoid. Combined mass spectrometry and nuclear magnetic resonance were used to monitor each reaction and conjugation products. Complete NMR peak assignment and detailed MS information on oxidized oligosialic acid and conjugates are reported. These studies provide a deeper understanding of the conjugation chemistry process and products, which can lead to a better controlled production process.

Development of a microbioreactor for glycoconjugate synthesis.

A microbioreactor immobilized with a synthase-type mutant enzyme, Endo-M-N175Q (glycosynthase) of endo-ß-N-acetylglucosaminidase derived from Mucor hiemalis (Endo-M), was constructed and used for glycoconjugate synthesis. The transglycosylation was performed with a reaction mixture containing an oxazoline derivative of sialo complex-type glycoside (SG), which was prepared from a sialo complex-type glycopeptide SGP derived from hen egg yolk, as a glycosyl donor and N-Fmoc-N-acetylglucosaminyl-l-asparagine [Fmoc-Asn(GlcNAc)-OH] as an acceptor. The reaction mixture was injected into a glycosynthase microbioreactor at a constant flow rate. Highly efficient and nearly stoichiometric transglycosylation occurred in the microbioreactor, and the transglycosylation product was eluted from the other end of the reactor. The glycosynthase microbioreactor was stable and could be used repeatedly for a long time.

Analysis of Glycoforms and Amino Acids in Infliximab and a Biosimilar Product Using New Method with LC/TOF-MS.

Biosimilar products of therapeutic antibodies have been launched all over the world. They can relieve some of the economic burden of medicines. Although clinical trials have demonstrated the equivalency of biosimilar products with their reference product, biosimilar products are not commonly used in clinical practice. One reason is that the structural difference between the reference product and a biosimilar one remains unclear. We analyzed glycoforms and amino acids of an infliximab biosimilar product approved in Japan compared to that of the reference product (Remicade®). By combination of papain digestion and LC/ time-of-flight (TOF)-MS, we established a valuable method to analyze these therapeutic antibodies. Nine glycoforms were detected in infliximab, and a difference in amino acids was observed. In the glycoforms of MMF, MGnF/GnMF, GnGn, GnGnF, AGnF/GnAF, and AAF, the relative intensities were significantly different between the reference and biosimilar product. Furthermore, we elucidated that the content rate of the C-terminal lysine was different among glycoforms. In conclusion, our analytical method can analyze not only amino acids but also carbohydrate chains of therapeutic antibodies, and will provide a useful strategy to evaluate bio-medicines including biosimilar antibodies.

Stress affects surface glycoconjugates of the rat endometrium at the time of implantation.

One of the treatments to infertility is In Vitro Fertilization (IVF). In the course of IVF, fertilization rate can be improved through stress reduction. Probably one of the causes of low outcome of IVF is changes in uterine glycoconjugates that are first site of contact between blastocyst and uterus, due to stress, e.g., stress of injection. Thus, the study of the injectional stress effects on implantation period is very important to improve the outcome of IVF. Sixteen mature female rats were divided to experimental and control groups. Experimental rats injected with 0.5cm3 distilled water intraperitoneally in diestrus or proestrus and 10 I.U HCG in estrus phase. Control rats injected only with 10 I.U HCG in estrus phase. The experimental and control rats mated with proven fertile male rats, sacrificed at 5.5 day of gestation (time of implantation) and their uterus horns removed. Uterine sections were stained with WGA, DBA, PNA, ConA, SBA and UEA lectins and grading of the intensity of the reaction in apical membrane, Golgi zone and basement membrane of uterine epithelial cells and uterine glands were performed by an arbitrary method. The intensity of the reaction to WGA and DBA in apical membrane and Golgi zone was significantly high in experimental group. It seems that injectional stress can decrease the rate of implantation through alteration in uterine glycoconjugates, e.g. increase in negatively charged glycoconjugates such as sialic acid, which reduce the receptivity of uterus for blastocyst.

Analysis of carbohydrates and glycoconjugates by matrix-assisted laser desorption/ionization mass spectrometry: an update for 2009-2010.

This review is the sixth update of the original article published in 1999 on the application of MALDI mass spectrometry to the analysis of carbohydrates and glycoconjugates and brings coverage of the literature to the end of 2010. General aspects such as theory of the MALDI process, matrices, derivatization, MALDI imaging, arrays and fragmentation are covered in the first part of the review and applications to various structural typed constitutes the remainder. The main groups of compound that are discussed in this section are oligo and polysaccharides, glycoproteins, glycolipids, glycosides and biopharmaceuticals. Many of these applications are presented in tabular form. Also discussed are medical and industrial applications of the technique, studies of enzyme reactions and applications to chemical synthesis.

The biofilm matrix of Campylobacter jejuni determined by fluorescence lectin-binding analysis.

Campylobacter jejuni is responsible for the most common bacterial foodborne gastroenteritis. Despite its fastidious growth, it can survive harsh conditions through biofilm formation. In this work, fluorescence lectin-binding analysis was used to determine the glycoconjugates present in the biofilm matrix of two well-described strains. Screening of 72 lectins revealed strain-specific patterns with six lectins interacting with the biofilm matrix of both strains. The most common sugar moiety contained galactose and N-acetylgalactosamine. Several lectins interacted with N-acetylglucosamine and sialic acid, probably originated from the capsular polysaccharides, lipooligosaccharides and N-glycans of C. jejuni. In addition, glycoconjugates containing mannose and fucose were detected within the biofilm, which have not previously been found in the C. jejuni envelope. Detection of thioflavin T and curcumin highlighted the presence of amyloids in the cell envelope without association with specific cell appendages. The lectins ECA, GS-I, HMA and LEA constitute a reliable cocktail to detect the biofilm matrix of C. jejuni.

Histochemical differences along the intestine of Corydoras paleatus (Siluriformes: Callichthyidae).

The Neotropical catfish Corydoras paleatus is a facultative air-breather and the caudal half of the intestine is involved in gas exchange. In South America, air-breathing fishes are found in tropical or sub-tropical freshwaters where the probability of hypoxia is high. The aim of this study was to characterize by traditional histochemical and lectinhistochemical methods the pattern of carbohydrate in the intestinal mucosa. Intestine samples were taken from 25 healthy adult specimens collected in Buenos Aires (Argentina). Samples were fixed by immersion in 10 % buffered formalin and routinely processed and embedded in paraffin wax. Subsequently, these sections were incubated in the biotinylated lectins battery. Labeled Streptavidin-Biotin (LSAB) system was used for detection, diaminobenzidine as chromogen and haematoxylin as a contrast. To locate and distinguish glycoconjugates (GCs) of the globet cells, we used the following histochemical methods: PAS; PAS*S; KOH/ PA*S; PA/Bh/KOH/PAS; KOH/PA*/Bh/PAS; Alcian Blue and Toluidine Blue at different pHs. Microscopically, the general structure of vertebrate intestine was observed and showed all the cell types characteristic of the intestinal epithelium. The cranial sector of catfish intestine is a site of digestion and absorption and its structure is similar to other fish groups. In contrast, enterocytes of the caudal portion are low cuboidal cells; and between these, globet cells and capillaries are observed, these latter may reach the mucosal lumen. Underlying the epithelium, observed a well-developed lamina propria-submucosa made of connective tissue; this layer was highly vascularized and did not exhibit glands. According to histochemistry, the diverse GCs elaborated and secreted in the intestine are associated with specific functions in relation to their physiological significance, with special reference to their role in lubrication, buffering effect and prevention of proteolytic damage to the epithelium together with other biological processes, such as osmoregulation and ion exchange. The lectinhistochemical analysis of the intestinal mucosa reveals the presence of terminal residues of glucose, mannose and galactose. In conclusion, this study has shown that GCs synthesized in the intestine of C. paleatus exhibit a high level of histochemical complexity and that the lectin binding pattern of the intestinal mucosa is characteristic of each species and the variations are related with the multiple functions performed by the mucus in the digestive tract. The information generated here may be a relevant biological tool for comparing and analyzing the possible glycosidic changes in the intestinal mucus under different conditions, such as changes in diet or different pathological stages.

Advanced Technologies in Sialic Acid and Sialoglycoconjugate Analysis.

Although the structural diversity of sialic acid (Sia) is rapidly expanding, understanding of its biological significance has lagged behind. Advanced technologies to detect and probe diverse structures of Sia are absolutely necessary not only to understand further biological significance but also to pursue medicinal and industrial applications. Here we describe analytical methods for detection of Sia that have recently been developed or improved, with a special focus on 9-O-acetylated N-acetylneuraminic acid (Neu5,9Ac), N-glycolylneuraminic acid (Neu5Gc), deaminoneuraminic acid (Kdn), O-sulfated Sia (SiaS), and di-, oligo-, and polysialic acid (diSia/oligoSia/polySia) in glycoproteins and glycolipids. Much more attention has been paid to these Sia and sialoglycoconjugates during the last decade, in terms of regulation of the immune system, neural development and function, tumorigenesis, and aging.

Visualization and analysis of EPS glycoconjugates of the thermoacidophilic archaeon Sulfolobus metallicus.

Biofilms are surface-associated colonies of microorganisms embedded in a matrix of extracellular polymeric substances (EPS). As EPS mediate the contact between cells and surfaces, an understanding of their composition and production is of particular interest. In this study, the EPS components of Sulfolobus metallicus DSM 6482(T) forming biofilms on elemental sulfur (S(0)) were investigated by confocal laser scanning microscopy (CLSM). In order to visualize cell and EPS distributions, biofilm cells were stained with various dyes specific for glycoconjugates, proteins, nucleic acids and lipids. Biofilm cells on S(0) were heterogeneously distributed and characterized as individual cells, microcolonies, and large clusters up to a hundred micrometers in diameter. The glycoconjugates in biofilms were detected by fluorescence lectin-binding analysis (FLBA). Screening of 72 commercially available lectins resulted in the selection of 21 lectins useful for staining biofilms of S. metallicus (T). Capsular EPS from planktonic cells were mainly composed of carbohydrates and proteins. In contrast, colloidal EPS from planktonic cells were dominated by carbohydrates. Proteins were found to be major components in EPS from biofilms on S(0). Using specific probes combined with CLSM, we showed that extracellular proteins and nucleic acids were present in the EPS matrix. Finally, we showed that S. metallicus (T) cells were embedded in a flexible EPS matrix. This study provides new insights into archaeal biofilms and EPS composition and properties with respect to their interactions with S(0).

The effect of phenol composition on the sensory profile of smoke affected wines.

Vineyards exposed to wildfire generated smoke can produce wines with elevated levels of lignin derived phenols that have acrid, metallic and smoky aromas and flavour attributes. While a large number of phenols are present in smoke affected wines, the effect of smoke vegetation source on the sensory descriptors has not been reported. Here we report on a descriptive sensory analysis of wines made from grapes exposed to different vegetation sources of smoke to examine: (1) the effect vegetation source has on wine sensory attribute ratings and; (2) associations between volatile and glycoconjugated phenol composition and sensory attributes. Sensory attribute ratings were determined by a trained sensory panel and phenol concentrations determined by gas chromatography-mass spectroscopy. Analysis of variance, principal component analysis and partial least squares regressions were used to evaluate the interrelationships between the phenol composition and sensory attributes. The results showed that vegetation source of smoke significantly affected sensory attribute intensity, especially the taste descriptors. Differences in aroma and taste from smoke exposure were not limited to an elevation in a range of detractive descriptors but also a masking of positive fruit descriptors. Sensory differences due to vegetation type were driven by phenol composition and concentration. In particular, the glycoconjugates of 4-hydroxy-3-methoxybenzaldehyde (vanillin), 1-(4-hydroxy-3-methoxyphenyl)ethanone (acetovanillone), 4-hydroxy-3,5-dimethoxybenzaldehyde (syringaldehyde) and 1-(4-hydroxy-3,5-dimethoxyphenyl)ethanone (acetosyringone) concentrations were influential in separating the vegetation sources of smoke. It is concluded that the detractive aroma attributes of smoke affected wine, especially of smoke and ash, were associated with volatile phenols while the detractive flavour descriptors were correlated with glycoconjugated phenols.

Food deprivation causes rapid changes in the abundance and glucidic composition of the cutaneous mucous cells of Atlantic salmon Salmo salar L.

Cutaneous mucus is the first physical and chemical barrier of fish. This slime layer is secreted by mucous cells located in the epidermis and is mainly composed of glycoproteins that have their origin in the diet. Therefore, food deprivation can potentially change the abundance and glucidic nature of skin mucous cells, thus changing the mucus properties. To test this hypothesis, we conducted an experiment with Atlantic salmon, Salmo salar L. Changes in the number and glucidic nature of epidermal mucus cells were analysed using standard techniques. The outcome of this study shows that food deprivation caused a rapid decrease in the density of epidermal mucous cells in Atlantic salmon. Lectin histochemistry revealed a change in the presence and stainability of some sugar residues in the mucous cells of unfed fish compared with fed fish. Given that the primary reason for mucus secretion in fish is for protection against infections, we speculate that the changes in the mucus properties caused by nutritional stress may affect their disease resistance. This fact is particularly important for fish that spend a period of time deprived of food, either as a part of their natural life cycle, or as part of farming practices.