Articles de revues : « Metaboliti volatili »

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Xu, Yaying, Changqing Zhu, Changjie Xu, Jun Sun, Donald Grierson, Bo Zhang et Kunsong Chen. « Integration of Metabolite Profiling and Transcriptome Analysis Reveals Genes Related to Volatile Terpenoid Metabolism in Finger Citron (C. medica var. sarcodactylis) ». Molecules 24, n^o 14 (15 juillet 2019) : 2564. http://dx.doi.org/10.3390/molecules24142564.

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Finger citron (Citrus medica var. sarcodactylis) is a popular ornamental tree and an important source of essential oils rich in terpenoids, but the mechanisms behind volatile formation are poorly understood. We investigated gene expression changes combined with volatile profiling of ten samples from three developing organs: flower, leaf, and fruit. A total of 62 volatiles were identified with limonene and γ-terpinene being the most abundant ones. Six volatiles were identified using partial least squares discriminant analysis (PLS-DA) that could be used as markers for distinguishing finger citron from other citrus species. RNA-Seq revealed 1,611,966,118 high quality clean reads that were assembled into 32,579 unigenes. From these a total of 58 terpene synthase (TPS) gene family members were identified and the spatial and temporal distribution of their transcripts was measured in developing organs. Transcript levels of transcription factor genes AP2/ERF (251), bHLH (169), bZIP (76), MYB (155), NAC (184), and WRKY (66) during finger citron development were also analyzed. From extracted subnetworks of three modules constructed by weighted gene co-expression network analysis (WGCNA), thirteen TPS genes and fifteen transcription factors were suggested to be related to volatile terpenoid formation. These results provide a framework for future investigations into the identification and regulatory network of terpenoids in finger citron.

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Lu, Xinxin, Lei Zhang, Wenyue Huang, Shujiang Zhang, Shifan Zhang, Fei Li, Hui Zhang, Rifei Sun, Jianjun Zhao et Guoliang Li. « Integrated Volatile Metabolomics and Transcriptomics Analyses Reveal the Influence of Infection TuMV to Volatile Organic Compounds in Brassica rapa ». Horticulturae 8, n^o 1 (8 janvier 2022) : 57. http://dx.doi.org/10.3390/horticulturae8010057.

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Turnip mosaic virus (TuMV), which is distributed almost all over the world and has a wide range of hosts, mainly brassica crops, was first described in Brassica rapa in the USA. Plant volatile compounds play an important role in the host searching behavior of natural enemies of herbivorous insects. In this study, TuMV-inoculated resistant and susceptible B. rapa lines were tested using volatile metabolome and transcriptome analyses. In volatile metabolome analysis, the volatile organic compounds (VOCs) were different after inoculation with TuMV in resistant B80124 and susceptible B80461, and the degree of downregulation of differentially expressed metabolites was more obvious than the degree of upregulation. Through transcriptome analysis, 70% of differentially expressed genes were in biological process, especially focusing on defense response, flavonoid biosynthetic process, and toxin metabolic process, which indicates that TuMV stress maybe accelerate the increase of VOCs. Integrating the metabolome and transcriptome analyses, after inoculating with TuMV, auxin regulation was upregulated, and ARF, IAA and GH3 were also upregulated, which accelerated cell enlargement and plant growth in tryptophan metabolism. The different genes in zeatin biosynthesis pathways were downregulated, which reduced cell division and shoot initiation. However, the metabolite pathways showed upregulation in brassinosteroid biosynthesis and α-linolenic acid metabolism, which could cause cell enlargement and a stress response. This study determined the difference in volatiles between normal plants and infected plants and may lay a foundation for anti-TuMV research in B. rapa.

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Zheng, Yucheng, Pengjie Wang, Xuejin Chen, Yun Sun, Chuan Yue et Naixing Ye. « Transcriptome and Metabolite Profiling Reveal Novel Insights into Volatile Heterosis in the Tea Plant (Camellia Sinensis) ». Molecules 24, n^o 18 (17 septembre 2019) : 3380. http://dx.doi.org/10.3390/molecules24183380.

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Tea aroma is a key indicator for evaluating tea quality. Although notable success in tea aroma improvement has been achieved with heterosis breeding technology, the molecular basis underlying heterosis remains largely unexplored. Thus, the present report studies the tea plant volatile heterosis using a high-throughput next-generation RNA-seq strategy and gas chromatography–mass spectrometry. Phenotypically, we found higher terpenoid volatile and green leaf volatile contents by gas chromatography–mass spectrometry in the F1 hybrids than in their parental lines. Volatile heterosis was obvious in both F1 hybrids. At the molecular level, the comparative transcriptomics analysis revealed that approximately 41% (9027 of 21,995) of the genes showed non-additive expression, whereas only 7.83% (1723 of 21,995) showed additive expression. Among the non-additive genes, 42.1% showed high parental dominance and 17.6% showed over-dominance. Among different expression genes with high parental dominance and over-dominance expression patterns, KEGG and GO analyses found that plant hormone signal transduction, tea plant physiological process related pathways and most pathways associated with tea tree volatiles were enriched. In addition, we identified multiple genes (CsDXS, CsAATC2, CsSPLA2, etc.) and transcription factors (CsMYB1, CsbHLH79, CsWRKY40, etc.) that played important roles in tea volatile heterosis. Based on transcriptome and metabolite profiling, we conclude that non-additive action plays a major role in tea volatile heterosis. Genes and transcription factors involved in tea volatiles showing over-dominance expression patterns can be considered candidate genes and provide novel clues for breeding high-volatile tea varieties.

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Xiang, Nan, Hui Xie, Liuwei Qin, Min Wang, Xinbo Guo et Wen Zhang. « Effect of Climate on Volatile Metabolism in ‘Red Globe’ Grapes (Vitis vinifera L.) during Fruit Development ». Foods 11, n^o 10 (16 mai 2022) : 1435. http://dx.doi.org/10.3390/foods11101435.

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With unique flavor and nutritional value, grapes are popular for eating and for the byproducts obtained in their processing. This study cultivated a popular grape variety, ‘Red Globe’, in two regions with different climates to investigate the discrepancies in their volatiles in response to climate. Saccharides, organic acids and transcriptomic and volatile metabolic analyses were studied separately via GC-FID, RNA sequencing and GC-MS/MS methods during the development of grape berries. In total, 83 volatiles were determined in samples, with (E)-2-hexenal the most abundant. Fatty acid derivatives and terpenoids in grapes showed discrepancies in different climates, and some of them were correlated to specific transcription factors. VvWRKY22 was influenced by climate conditions and was relative to saccharide accumulation. MYB-related transcription factors (TFs) were highly correlated with volatiles that accumulated during fruit ripening, especially decanal. Terpenoids showed correlations with a gene module that contained ERFs and HSFs. The findings support the hypothesis that fruit maturity and volatile formations vary in grape berries under different climates. Moreover, specific TFs could participate in volatile accumulations. The given results not only serve to enrich theoretical knowledge on the regulatory mechanism of volatiles in grapes, but also provide guidance for enhancing grape flavor and aroma by modulating cultivational conditions.

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Xiang, Nan, Yihan Zhao, Bing Zhang, Qiuming Gu, Weiling Chen et Xinbo Guo. « Volatiles Accumulation during Young Pomelo (Citrus maxima (Burm.) Merr.) Fruits Development ». International Journal of Molecular Sciences 23, n^o 10 (18 mai 2022) : 5665. http://dx.doi.org/10.3390/ijms23105665.

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As widely planted fruits with high nutritional and medical values, pomelos are managed systematically to achieve the largest economic benefits. But the annual shedding of young pomelos, which could be applied as feedstocks for essential oil extraction with their abundant volatiles, leads to a waste of source. The present study selected two commonly planted pomelo (Citrus maxima (Burm.) Merr.) varieties in Southern China, to investigate the volatile profiles during young pomelo fruits development. Combing transcriptomic analysis, this study aimed at identifying the prominent volatile components in young pomelo fruits in order to preferably extract profitable volatiles, as well, increasing the knowledge concerning regulatory roles of transcription factors (TFs) on volatiles accumulation in young pomelos. Totally 29 volatiles were identified, including 14 monoterpenoids and 13 sesquiterpenoids. Diprene was the principal component with the highest amount. Volatiles were generally decreased during fruits development but preferable stages were figured out for volatile collections. 12 and 17 TFs were related to developing time while ERF003 and MYC2 were highly correlated to monoterpenoids. These findings put forward the comprehensive usages of young pomelos and enriched the regulatory roles of TFs on both fruit development and volatiles metabolism.

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Whiting, M. D., G. Paliyath et D. P. Murr. « Analysis of Volatile Evolution from Scald-developing and Nondeveloping Sides of Apple Fruits ». HortScience 32, n^o 3 (juin 1997) : 457C—457. http://dx.doi.org/10.21273/hortsci.32.3.457c.

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Apple fruits (Malus domestica Borkh. cv. `Red Delicious') stored for 6 months at 2°C in air were analyzed for headspace volatiles by SPME-GC and for surface components by HPLC of hexane extracts. Analysis of headspace volatiles evolved from whole fruit showed five major volatiles that were identified previously as: acetic acid, hexyl ester; hexanoic acid, butyl ester; octanoic acid, propyl ester; hexanoic acid, hexyl ester; and the sesquiterpene, α-farnesene. No significant differences existed in these volatiles between scald-developing and non-scald developing apples. To explore potential differences in volatile evolution, fruit developing scald were cut (axial plane) into scalding and non-scalding halves for analysis. In all cases, volatile emission was much higher from the non-scalding side of the fruit, and the ratio of volatile levels from non-scalding to scalding averaged greater that 2. Various regions of tissue from the same fruit were extracted in hexane for estimation of levels of α-farnesene and its potential catabolites by HPLC. The levels and proportions of the components were nearly identical to those observed during headspace volatile analysis of half fruit. The results suggest that there are potential differences in α-farnesene metabolism an/or permeability of apple cuticle to volatiles between scald-developing and non-scald developing regions of apple fruit.

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Fitria, Rizki, Djarot Sasongko Hami Seno, Bambang Pontjo Priosoeryanto, Najmah Najmah et Waras Nurcholis. « Cytotoxic Activity of Volatile Compounds in Cymbopogon nardus’ Essential Oils ». Justek : Jurnal Sains dan Teknologi 5, n^o 2 (2 novembre 2022) : 90. http://dx.doi.org/10.31764/justek.v5i2.10194.

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Abstract: Plants produce a variety of secondary metabolites, one of which is essential oils that contain a variety of volatile compounds and are useful for humans. Cymbopogon nardus contains volatile compounds that can inhibit the proliferation of cancer cells. This research aims to explore the antiproliferation activity of C.nardus’ essential oils with different concentrations against breast cancer Michigan Cancer Foundation-7 (MCF-7) cells. Antiproliferation test was carried out with total cells method using trypan blue and cells were calculated using a microscope. Gas Chromatography-Mass Spectrometer (GC-MS) was performed to identify the volatile compounds. The results showed that the Inhibitory Concentration 50 (IC50) value was 359.6 ppm with an inhibition percent of 44.49% at 170 ppm. Meanwhile, inhibition percent against Vero normal cell was 29.04%, compared to Doxorubicin 35.23%. The dominant volatile compound in C. nardus’ essential oil were Geraniol and Citronellol.Abstrak Tanaman menghasilkan berbagai macam metabolit sekunder, salah satunya dalam bentuk minyak atsiri yang mengandung berbagai macam senyawa volatil yang berguna bagi manusia. Cymbopogon nardus mengandung senyawa volatil yang dapat menghambat proliferasi sel kanker. Penelitian ini bertujuan untuk mengetahui aktifitas antiproliferasi minyak atsiri C. nardus dengan beberapa konsentrasi terhadap sel kanker payudara Michigan State Foundation-7 (MCF-7). Uji antiproliferasi dilakukan dengan metode total sel menggunakan trypan blue dan sel dihitung menggunakan mikroskop. Gas Chromatography-Mass Spectrometer (GC-MS) dilakukan untuk mengidentifikasi senyawa volatil. Hasil menunjukkan bahwa konsentrasi penghambatan 50 (IC50) sebesar 359.6 ppm dengan persen penghambatan sebesar 44.49% pada konsentrasi 170 ppm. Sementara itu, persen ihibisi terhadap sel normal Vero sebesar 29.04%, dibandingkan dengan Doksorubisin yang sebesar 35.23%. Senyawa volatil dominan yang terdapat pada C. nardus adalah Geraniol dan Citronellol.

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Kharasch, Evan D., Jesara L. Schroeder, H. Denny Liggitt, Sang B. Park, Dale Whittington et Pamela Sheffels. « New Insights into the Mechanism of Methoxyflurane Nephrotoxicity and Implications for Anesthetic Development (Part 1) ». Anesthesiology 105, n^o 4 (1 octobre 2006) : 726–36. http://dx.doi.org/10.1097/00000542-200610000-00019.

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Background Methoxyflurane nephrotoxicity results from biotransformation; inorganic fluoride is a toxic metabolite. Concern exists about potential renal toxicity from volatile anesthetic defluorination, but many anesthetics increase fluoride concentrations without consequence. Methoxyflurane is metabolized by both dechlorination to methoxydifluoroacetic acid (MDFA, which may degrade to fluoride) and O-demethylation to fluoride and dichloroacetatic acid. The metabolic pathway responsible for methoxyflurane nephrotoxicity has not, however, been identified, which was the aim of this investigation. Methods Experiments evaluated methoxyflurane metabolite formation and effects of enzyme induction or inhibition on methoxyflurane metabolism and toxicity. Rats pretreated with phenobarbital, barium sulfate, or nothing were anesthetized with methoxyflurane, and renal function and urine methoxyflurane metabolite excretion were assessed. Phenobarbital effects on MDFA metabolism and toxicity in vivo were also assessed. Metabolism of methoxyflurane and MDFA in microsomes from livers of pretreated rats was determined in vitro. Results Phenobarbital pretreatment increased methoxyflurane nephrotoxicity in vivo (increased diuresis and blood urea nitrogen and decreased urine osmolality) and induced in vitro hepatic microsomal methoxyflurane metabolism to inorganic fluoride (2-fold), dichloroacetatic acid (1.5-fold), and MDFA (5-fold). In contrast, phenobarbital had no influence on MDFA renal effects in vivo or MDFA metabolism in vitro or in vivo. MDFA was neither metabolized to fluoride nor nephrotoxic. Barium sulfate diminished methoxyflurane metabolism and nephrotoxicity in vivo. Conclusions Fluoride from methoxyflurane anesthesia derives from O-demethylation. Phenobarbital increases in methoxyflurane toxicity do not seem attributable to methoxyflurane dechlorination, MDFA toxicity, or MDFA metabolism to another toxic metabolite, suggesting that nephrotoxicity is attributable to methoxyflurane O-demethylation. Fluoride, one of many metabolites from O-demethylation, may be toxic and/or reflect formation of a different toxic metabolite. These results may have implications for interpreting anesthetic defluorination, volatile anesthetic use, and methods to evaluate anesthetic toxicity.

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Cozzolino, Rosaria, Matteo Stocchero, Rosa Perestrelo et José S. Câmara. « Comprehensive Evaluation of the Volatomic Fingerprint of Saffron from Campania towards Its Authenticity and Quality ». Foods 11, n^o 3 (27 janvier 2022) : 366. http://dx.doi.org/10.3390/foods11030366.

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The volatile profiles of eight saffron samples (seven cultivated and one spontaneous) grown in different geographical districts within the Campania region (southern Italy) were compared. Using headspace solid-phase microextraction coupled to gas chromatography–mass spectrometry (HS-SPME/GC-MS), overall, 80 volatiles were identified in the eight landraces. Among them, safranal and its isomers and other related compounds such as isophorones, which are not only key odorants but also pharmacologically active metabolites, have been detected in all the investigated samples. Principal Component Analysis performed on the volatiles’ compounds revealed that the spontaneous sample turned out to be an outlier. In particular, the volatile organic compounds (VOCs) profile of the spontaneous saffron presented four lilac aldehydes and four lilac alcohol isomers, which, to the authors’ knowledge, have never been identified in the volatile signature of this spice. The multivariate statistical analysis allowed the discrimination of the seven cultivate saffron ecotypes in four well-separated clusters according to variety. Moreover, 20 VOCs, able to differentiate the clusters in terms of single volatile metabolite, were discovered. Altogether, these results could contribute to identifying possible volatile signature metabolites (biomarkers) or patterns that discriminate saffron samples grown in Campania region on a molecular basis, encouraging future biodiversity programs to preserve saffron landraces revealing valuable genetic resources.

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Kiyota, H., S. Otsuka, A. Yokoyama, S. Matsumoto, H. Wada et S. Kanazawa. « Effects of highly volatile organochlorine solvents on nitrogen metabolism and microbial counts ». Soil and Water Research 7, No. 3 (10 juillet 2012) : 109–16. http://dx.doi.org/10.17221/30/2011-swr.

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The effects of highly volatile organochlorine solvents (1,1,1-trichloroethane, TCET; trichloroethylene, TCE; and tetrachloroethylene, PCE) on soil nitrogen cycle and microbial counts were investigated using volcanic ash soil with different fertilizations. All the solvents significantly inhibited the activity of the cycle under the sealed conditions with 10 to 50 mg/g (dry soil) solvents added. No significant difference between the solvents, and between fertilization plots, was observed. Nitrate ion was not accumulated, and instead, ammonium ion was highly accumulated in the presence of the solvents. Nitrite ion was partially detected, while l-glutaminase activity was inhibited. The growths of ammonification, nitritation, nitratation and denitrification bacteria, and filamentous fungi were significantly inhibited in the presence of 10 mg/g (dry soil) of the solvents. 

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Kaczmarska, Kornelia, Matthew Taylor, Udayasika Piyasiri et Damian Frank. « Flavor and Metabolite Profiles of Meat, Meat Substitutes, and Traditional Plant-Based High-Protein Food Products Available in Australia ». Foods 10, n^o 4 (8 avril 2021) : 801. http://dx.doi.org/10.3390/foods10040801.

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Demand for plant-based proteins and plant-based food products is increasing globally. This trend is driven mainly by global population growth and a consumer shift towards more sustainable and healthier diets. Existing plant-based protein foods and meat mimetics often possess undesirable flavor and sensory properties and there is a need to better understand the formation of desirable meat-like flavors from plant precursors to improve acceptance of novel high-protein plant foods. This study aimed to comprehensively characterize the non-volatile flavor metabolites and the volatiles generated in grilled meat (beef, chicken, and pork) and compare these to commercially available meat substitutes and traditional high-protein plant-based foods (natto, tempeh, and tofu). Solid phase microextraction with gas-chromatography mass-spectrometry was used for elucidation of the flavor volatilome. Untargeted characterization of the non-volatile metabolome was conducted using Orbitrap mass spectrometry and Compound DiscovererTM datamining software. The study revealed greater diversity and higher concentrations of flavor volatiles in plant-based foods in comparison to grilled meat, although the odor activity of specific volatiles was not considered. On average, the total amount of volatiles in plant-based products were higher than in meat. A range of concentrations of free amino acids, dipeptide, tripeptides, tetrapeptides, nucleotides, flavonoids, and other metabolites was identified in meat and plant-based foods.

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Li, Zhenzhao, Minh Ha, Damian Frank, Peter McGilchrist et Robyn Dorothy Warner. « Volatile Profile of Dry and Wet Aged Beef Loin and Its Relationship with Consumer Flavour Liking ». Foods 10, n^o 12 (15 décembre 2021) : 3113. http://dx.doi.org/10.3390/foods10123113.

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This study investigated the effect of ageing method and ageing time on the volatile profiles of grilled beef striploins (Longissimus thoracis et lumborum) and their relationship with consumer flavour liking. Volatiles were measured in grilled steaks subjected to 35 days of dry ageing, 35 days of wet ageing, 56 days of dry ageing or 56 days of wet ageing, using headspace-solid-phase microextraction followed by gas chromatography-mass spectrometry. Gas chromatography-olfactometry-mass spectrometry was also conducted on 35-day wet and dry aged samples to identify volatiles with high odour impact. The concentration of many odour impact volatiles, e.g., 3-hydroxy-2-butanone, 2-acetyl-2-thiazoline, and various alkyl-pyrazines, was significantly higher in dry aged beef compared to wet aged beef (p < 0.05). Several odour impact volatiles, e.g., 2-acetyl-1-pyrroline, and alkyl-pyrazines, decreased significantly with ageing time (p < 0.05), while volatile products of lipid oxidation and microbial metabolism increased with ageing time. Partial least-squares regression analysis showed that the higher consumer flavour liking for 35-day dry aged beef was associated with higher concentrations of desirable odour-active volatiles.

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Park, Min-Kyung, Soyeon Lee et Young-Suk Kim. « Effects of pH and Osmotic Changes on the Metabolic Expressions of Bacillus subtilis Strain 168 in Metabolite Pathways including Leucine Metabolism ». Metabolites 12, n^o 2 (25 janvier 2022) : 112. http://dx.doi.org/10.3390/metabo12020112.

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Bacillus subtilis is often exposed to diverse culture conditions with the aim of improving hygiene or food quality. This can lead to changes in the volatile metabolite profiles related to the quality of fermented foods. To comprehensively interpret the associated metabolic expressions, changes in intracellular primary and extracellular secondary volatile metabolites were investigated by exposing B. subtilis to an alkaline pH (BP, pH 8.0) and a high salt concentration (BS, 1 M). In particular, B. subtilis was cultured in a leucine-enriched medium to investigate the formation of leucine-derived volatile metabolites. This study observed metabolic changes in several metabolic pathways, including carbohydrate metabolism, amino acid metabolism, fatty acid metabolism, and leucine degradation. The formation of proline (an osmolyte), furans, pyrrole, and monosaccharide sugars (glucose, galactose, and fructose) was enhanced in BS, whereas fatty acid derivatives (ketones and alcohols) increased in BP. In the case of leucine degradation, 3-methyl-butanal and 3-methylbutanol could be salt-specific metabolites, while the contents of 3-methylbutanoic acid and 3-methylbutylacetate increased in BP. These results show culture condition-specific metabolic changes, especially secondary volatile metabolites related to the sensory property of foods, in B. subtilis.

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Song, Yong, Na Qiao, Chong Wei Li, Ting Ting Wen et Fang Yu Liu. « SPME-GC/MS Analysis of Volatile Components from Air-Dried Sausage during Processing ». Advanced Materials Research 781-784 (septembre 2013) : 1614–18. http://dx.doi.org/10.4028/www.scientific.net/amr.781-784.1614.

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Air-dried sausage (ADS) is a kind of Chinese traditional spontaneous fermented sausages, and is popular to consumers. In order to investigate the changes of volatile components from ADS during processing, solid phase micro-extraction (SPME) was employed to extract volatiles from samples of different processing stages. And then, volatile compounds were separated and identified by capillary gas chromatography-mass spectrometry (GC/MS). In this work, 19, 25 and 29 kinds of volatile compounds were identified from samples periodically taken at 0 d, 2 d and 7 d. 32 volatile compounds were identified in total during the entire process. The main volatile compounds during the processing of ADS were ethyl alcohol, hexanal, D-limonene, 2-pentanone and hexanoic acid ethyl ester. Branched-chain aldehydes: 3-methylbutanal and 2-methylbutanal were also detected and identified. The formation of these volatile compounds may be attributed to the added alcohol, spices, fat oxidation, amino acid metabolism, microbial activity and the interaction between these factors.

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Pennerman, Kayla K., Guohua Yin et Joan W. Bennett. « Eight-carbon volatiles : prominent fungal and plant interaction compounds ». Journal of Experimental Botany 73, n^o 2 (2 novembre 2021) : 487–97. http://dx.doi.org/10.1093/jxb/erab438.

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Abstract Signaling via volatile organic compounds (VOCs) has historically been studied mostly by entomologists; however, botanists and mycologists are increasingly aware of the physiological potential of chemical communication in the gas phase. Most research to date focuses on the observed effects of VOCs on different organisms such as differential growth or metabolite production. However, with the increased interest in volatile signaling, more researchers are investigating the molecular mechanisms for these effects. Eight-carbon VOCs are among the most prevalent and best-studied fungal volatiles. Therefore, this review emphasizes examples of eight-carbon VOCs affecting plants and fungi. These compounds display different effects that include growth suppression in both plants and fungi, induction of defensive behaviors such as accumulation of mycotoxins, phytohormone signaling cascades, and the inhibition of spore and seed germination. Application of ‘-omics’ and other next-generation sequencing techniques is poised to decipher the mechanistic basis of volatiles in plant–fungal communication.

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Derbali, Ezzedine, Louis-Philippe Vezina et Joseph Makhlouf. « Effects of Anaerobic Atmosphere on the Metabolism of Sulfur Volatile Compounds Produced by Broccoli ». HortScience 31, n^o 4 (août 1996) : 635e—635. http://dx.doi.org/10.21273/hortsci.31.4.635e.

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Objectionable off-odors are produced by broccoli (Brassica oleracea, L.) when it is held under anaerobic conditions. These off-odors were attributed to sulfur volatile compounds mainly methanethiol (MT) and hydrogen sulfide. The present study was undertaken to investigate the effects of anaerobic conditions on the metabolism and emission of sulfur volatiles by broccoli. Inhibition assays using aminooxyacetic acid (AOA)—a potential inhibitor of pyridoxal-phosphate-dependent enzymes-confirmed the enzymatic origin of these volatiles. However, anaerobic atmosphere had no inducible effect on the enzymes cystine lyase, cysteine desulfhydrases and S-alkylcysteine lyase. These pyridoxal-phosphate-dependent enzymes thought to catalyze the respective degradation of cystine, cysteine and S-methyl-L-cysteine to sulfur volatiles showed no significant activity increase. Storage of sterile broccoli seedlings under anaerobic atmosphere resulted in an important increase of the content of sulfur amino acids that corresponded to an increased emission of sulfur volatiles. Cysteine and methionine content increased particularly at 24 hours and decreased later. Whereas, S-methyl-L-cysteine content increase was more obvious after 48 hours. The results suggest a possible involvement of the pathways for synthesis and breakdown of sulfur amino acids via methionine.

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Qiao, Yifeng, Diana Hawkins, Katie Parish-Virtue, Bruno Fedrizzi, Sarah J. Knight et Rebecca C. Deed. « Contribution of Grape Skins and Yeast Choice on the Aroma Profiles of Wines Produced from Pinot Noir and Synthetic Grape Musts ». Fermentation 7, n^o 3 (27 août 2021) : 168. http://dx.doi.org/10.3390/fermentation7030168.

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The aroma profile is a key component of Pinot noir wine quality, and this is influenced by the diversity, quantity, and typicity of volatile compounds present. Volatile concentrations are largely determined by the grape itself and by microbial communities that produce volatiles during fermentation, either from grape-derived precursors or as byproducts of secondary metabolism. The relative degree of aroma production from grape skins compared to the juice itself, and the impact on different yeasts on this production, has not been investigated for Pinot noir. The influence of fermentation media (Pinot noir juice or synthetic grape must (SGM), with and without inclusion of grape skins) and yeast choice (commercial Saccharomyces cerevisiae EC1118, a single vineyard mixed community (MSPC), or uninoculated) on aroma chemistry was determined by measuring 39 volatiles in finished wines using headspace solid-phase microextraction (HS-SPME) coupled with gas chromatography–mass spectrometry (GC-MS). Fermentation medium clearly differentiated the volatile profile of wines with and without yeast, while differences between EC1118 and MSPC wines were only distinct for Pinot noir juice without skins. SGM with skins produced a similar aroma profile to Pinot noir with skins, suggesting that grape skins, and not the pulp, largely determine the aroma of Pinot noir wines.

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Cheng, Guo-Ting, Yu-Shun Li, Shi-Ming Qi, Jin Wang, Pan Zhao, Qian-Qi Lou, Yan-Feng Wang, Xiang-Qian Zhang et Yan Liang. « SlCCD1A Enhances the Aroma Quality of Tomato Fruits by Promoting the Synthesis of Carotenoid-Derived Volatiles ». Foods 10, n^o 11 (3 novembre 2021) : 2678. http://dx.doi.org/10.3390/foods10112678.

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The loss of volatiles results in the deterioration of flavor in tomatoes. Volatiles are mainly derived from fatty acid, carotenoid, phenylpropane, and branched chain amino acids. In this study, the tomato accession CI1005 with a strong odor and accession TI4001 with a weak odor were analyzed. The volatile contents were measured in tomato fruits using gas chromatography-mass spectrometry. The scores of tomato taste and odor characteristics were evaluated according to hedonistic taste and olfaction. It was found that the content of fatty acid-derived volatiles accounted for more than half of the total volatiles that had grassy and fatty aromas. Phenylpropane-derived volatiles had irritation and floral aromas. Branched-chain amino acid-derived volatiles had a caramel aroma. Carotenoid-derived volatiles had floral, fruity, fatty, and sweet-like aromas, preferred by consumers. A lack of carotenoid-derived volatiles affected the flavor quality of tomato fruits. The accumulation of carotenoid-derived volatiles is regulated by carotenoid cleavage oxygenases (CCDs). A tissue-specific expression analysis of the SlCCD genes revealed that the expression levels of SlCCD1A and SlCCD1B were higher in tomato fruits than in other tissues. The expression levels of SlCCD1A and SlCCD1B were consistent with the trend of the carotenoid-derived volatile contents. The expression of SlCCD1A was higher than that for SlCCD1B. A bioinformatics analysis revealed that SlCCD1A was more closely linked to carotenoid metabolism than SlCCD1B. The overexpression of SlCCD1A indicated that it could cleave lycopene, α-carotene, and β-carotene to produce 6-methyl-5-hepten-2-one, geranylacetone, α-ionone, and β-ionone, increasing the floral, fruity, fatty, and sweet-like aromas of tomato fruits. The flavor quality of tomato fruits could be improved by overexpressing SlCCD1A.

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Yang, Shunbo, Dongmei Li, Shanshan Li, Huijuan Yang et Zhengyang Zhao. « GC-MS Metabolite and Transcriptome Analyses Reveal the Differences of Volatile Synthesis and Gene Expression Profiling between Two Apple Varieties ». International Journal of Molecular Sciences 23, n^o 6 (9 mars 2022) : 2939. http://dx.doi.org/10.3390/ijms23062939.

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Aroma is a key quality attribute of apples, making major contributions to commercial value and consumer choice. However, the mechanism underlying molecular regulation of aroma formation genes and transcription factors remains poorly understood in apples. Here, we investigated the aroma volatile profiles of two apple varieties with distinctive flavors using headspace solid-phase microextraction (HS-SPME) combined with gas chromatography–mass spectrometry (GC-MS). A total of 35 volatile compounds were identified in Granny Smith and Jonagold apples. Aldehydes were the most abundant volatiles contributing to the aroma in Granny Smith apple while esters were the dominant volatile compounds in Jonagold apple. In order to know more about the expression levels of aroma-related genes involved in the metabolic pathways, transcriptome sequencing of these two different apple varieties was conducted utilizing the Illumina platform. In total, 94 differentially expressed genes (DEGs) were found in the fatty acid metabolism, amino acid metabolism, the mevalonate pathway and phenylpropanoid pathway. Furthermore, compared to the Granny Smith apple, the expression of multiple genes and transcription factors were upregulated in the Jonagold apple, which might play important roles in the synthesis of aroma volatile compounds. Our study contributes toward better understanding on the molecular mechanism of aroma synthesis in apples and provides a valuable reference for metabolic engineering and flavor improvement in the future.

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O'HALLORAN, D. M., et A. M. BURNELL. « An investigation of chemotaxis in the insect parasitic nematode Heterorhabditis bacteriophora ». Parasitology 127, n^o 4 (octobre 2003) : 375–85. http://dx.doi.org/10.1017/s0031182003003688.

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We tested the chemotactic responses of dauer juvenile stages (DJs) of the insect parasitic nematode Heterorhabditis bacteriophora to a variety of compounds that are known to be highly attractive or highly repellent to Caenorhabditis elegans. While H. bacteriophora DJs respond to alcohols and some aromatic compounds as well as to host metabolites such as uric acid and CO2, the most notable difference in the responses of these two nematodes is that H. bacteriophora DJs are unresponsive to a large number of compounds which C. elegans finds highly attractive. The latter compounds are typical by-products of bacterial metabolism and include aldehydes, esters, ketones and short-chain alcohols. While C. elegans finds long-chain alcohols (e.g. 1-heptanol and 1-octanol) repellent and short-chain alcohols highly attractive, H. bacteriophora DJs are strongly attracted to 1-heptanol, 1-octanol and 1-nonanol and find short-chain alcohols to be only slightly attractive. Parasitic-stage H. bacteriophora nematodes show a very weak chemotactic response to volatile molecules that DJs find highly attractive. Our results suggest that, associated with the adoption of a parasitic mode of life by Heterorhabditis, there was an adaptive change in chemotactic behaviour of the infective stages, resulting in a decreased sensitivity to volatile by-products of bacterial metabolism and an increased sensitivity towards long-chain alcohols and other insect-specific volatiles and possibly also to herbivore-induced plant volatiles.

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Mattheis, J. P., et D. A. Buchanan. « CHANGE IN SYNTHESIS OF NON-ETHYLENE VOLATILES FOLLOWING APPLE FRUIT STORAGE IN ATMOSPHERES INDUCING ANAEROBIC METABOLISM. » HortScience 25, n^o 9 (septembre 1990) : 1146c—1146. http://dx.doi.org/10.21273/hortsci.25.9.1146c.

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Apple fruit storage lie is prolonged by low-oxygen cold storage, however, ethanol accumulates when oxygen concentration is reduced below the Pasteur point, Upon return to aerobic conditions, dissipation of ethanol occurs due to physical (evaporation) and biochemical processes. Oxidation of ethanol by apple fruit occurs at a slow rate, but ethanol also serves es a substrate for fruit volatile synthesis. This study was conducted to determine changes in concentrations of ethanol and other non-ethylene apple fruit volatiles following periods of anaerobiosis. `Delicious' apples were obtained from a commercial warehouse and stored at 0.05% O2, 0.2% CO2 and 1 C. One day following return to ambient oxygen conditions, several volatiles were identified from anaerobic fruit that were nor produced by the control fruit. All were eaters that contained an ethyl group as the alcohol-derived portion, These included ethyl acetate, ethyl butyrate, ethyl 2-methyl butyrate, ethyl hexanoate and ethyl octanoate. Several esters produced by the controls were not detectable from anaerobic fruit including butyl butyrate, butyl 2-methyl butyrate, propyl hexanoate and 3-methyl butyl hexanoate. After 7 days ripening at 20 C, the amount of ethanol and the additional ethylesters was reduced in anaerobic fruit. Synthesis of esters produced by control fruit but nor by anaerobic fruit during the initial volatile sampling had resumed after 7 days.

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Goliáš, J., P. Hic et J. Kaňová. « Effect of low oxygen storage conditions on volatile emissions and anaerobic metabolite concentrations in two plum fruit cultivars ». Horticultural Science 37, No. 4 (3 novembre 2010) : 145–54. http://dx.doi.org/10.17221/78/2009-hortsci.

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By harvest time, small amounts of acetaldehyde were accumulated in the flesh of plums, such as 0.31 mg/l for the cv. Stanley and 1.03 mg/l for the cv. Valjevka. This relative difference in concentrations remained constant throughout the whole period of storage in a regular atmosphere. The long-term effects of higher concentrations of CO<sub>2</sub> are the same as for very low oxygen concentrations; and significant amounts of ethanol accumulate in the tissue. Out of a total number of 42 different odour compounds identified in the juice, there were 11 alcohols, 6 aldehydes, 17 esters, 2 terpenes, 3 organic acids, and 1 lactone. Very low oxygen atmospheres slow down the production of esters and aldehydes, but have little effect on the production of lactones and terpenes. It was shown that a very low oxygen concentration, without much CO<sub>2</sub> (Fluctuating anaerobiosis treatment), does not encourage the production of significant amounts of ethanol and acetaldehyde in the fruit flesh, but does significantly slow the biosynthesis of aromatic volatiles.

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Maxwell, Tyler, Richard Blair, Yuemin Wang, Andrew Kettring, Sean Moore, Matthew Rex et James Harper. « A Solvent-Free Approach for Converting Cellulose Waste into Volatile Organic Compounds with Endophytic Fungi ». Journal of Fungi 4, n^o 3 (26 août 2018) : 102. http://dx.doi.org/10.3390/jof4030102.

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Simple sugars produced from a solvent-free mechanocatalytic degradation of cellulose were evaluated for suitability as a growth medium carbon source for fungi that produce volatile organic compounds. An endophytic Hypoxylon sp. (CI-4) known to produce volatiles having potential value as fuels was initially evaluated. The growth was obtained on a medium containing the degraded cellulose as the sole carbon source, and the volatile compounds produced were largely the same as those produced from a conventional dextrose/starch diet. A second Hypoxylon sp. (BS15) was also characterized and shown to be phylogenetically divergent from any other named species. The degraded cellulose medium supported the growth of BS15, and approximately the same quantity of the volatile compounds was produced as from conventional diets. Although the major products from BS15 grown on the degraded cellulose were identical to those from dextrose, the minor products differed. Neither CI-4 or BS15 exhibited growth on cellulose that had not been degraded. The extraction of volatiles from the growth media was achieved using solid-phase extraction in order to reduce the solvent waste and more efficiently retain compounds having low vapor pressures. A comparison to more conventional liquid–liquid extraction demonstrated that, for CI-4, both methods gave similar results. The solid-phase extraction of BS15 retained a significantly larger variety of the volatile compounds than did the liquid–liquid extraction. These advances position the coupling of solvent-free cellulose conversion and endophyte metabolism as a viable strategy for the production of important hydrocarbons.

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Kuhalskaya, Anastasiya, Micha Wijesingha Ahchige, Leonardo Perez de Souza, José Vallarino, Yariv Brotman et Saleh Alseekh. « Network Analysis Provides Insight into Tomato Lipid Metabolism ». Metabolites 10, n^o 4 (14 avril 2020) : 152. http://dx.doi.org/10.3390/metabo10040152.

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Metabolic correlation networks have been used in several instances to obtain a deeper insight into the complexity of plant metabolism as a whole. In tomato (Solanum lycopersicum), metabolites have a major influence on taste and overall fruit quality traits. Previously a broad spectrum of metabolic and phenotypic traits has been described using a Solanum pennellii introgression-lines (ILs) population. To obtain insights into tomato fruit metabolism, we performed metabolic network analysis from existing data, covering a wide range of metabolic traits, including lipophilic and volatile compounds, for the first time. We provide a comprehensive fruit correlation network and show how primary, secondary, lipophilic, and volatile compounds connect to each other and how the individual metabolic classes are linked to yield-related phenotypic traits. Results revealed a high connectivity within and between different classes of lipophilic compounds, as well as between lipophilic and secondary metabolites. We focused on lipid metabolism and generated a gene-expression network with lipophilic metabolites to identify new putative lipid-related genes. Metabolite–transcript correlation analysis revealed key putative genes involved in lipid biosynthesis pathways. The overall results will help to deepen our understanding of tomato metabolism and provide candidate genes for transgenic approaches toward improving nutritional qualities in tomato.

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Ślefarska-Wolak, Daria, Christine Heinzle, Andreas Leiherer, Clemens Ager, Axel Muendlein, Linda Mezmale, Marcis Leja et al. « Volatilomic Signatures of AGS and SNU-1 Gastric Cancer Cell Lines ». Molecules 27, n^o 13 (22 juin 2022) : 4012. http://dx.doi.org/10.3390/molecules27134012.

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In vitro studies can help reveal the biochemical pathways underlying the origin of volatile indicators of numerous diseases. The key objective of this study is to identify the potential biomarkers of gastric cancer. For this purpose, the volatilomic signatures of two human gastric cancer cell lines, AGS (human gastric adenocarcinoma) and SNU-1 (human gastric carcinoma), and one normal gastric mucosa cell line (GES-1) were investigated. More specifically, gas chromatography mass spectrometry has been applied to pinpoint changes in cell metabolism triggered by cancer. In total, ten volatiles were found to be metabolized, and thirty-five were produced by cells under study. The volatiles consumed were mainly six aldehydes and two heterocyclics, whereas the volatiles released embraced twelve ketones, eight alcohols, six hydrocarbons, three esters, three ethers, and three aromatic compounds. The SNU-1 cell line was found to have significantly altered metabolism in comparison to normal GES-1 cells. This was manifested by the decreased production of alcohols and ketones and the upregulated emission of esters. The AGS cells exhibited the increased production of methyl ketones containing an odd number of carbons, namely 2-tridecanone, 2-pentadecanone, and 2-heptadecanone. This study provides evidence that the cancer state modifies the volatilome of human cells.

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Misran, Azizah, Priya Padmanabhan, J. Alan Sullivan, Shahrokh Khanizadeh et Gopinadhan Paliyath. « Composition of phenolics and volatiles in strawberry cultivars and influence of preharvest hexanal treatment on their profiles ». Canadian Journal of Plant Science 95, n^o 1 (janvier 2015) : 115–26. http://dx.doi.org/10.4141/cjps-2014-245.

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Misran, A., Padmanabhan, P., Sullivan, J. A., Khanizadeh, S. and Paliyath, G. 2015. Composition of phenolics and volatiles in strawberry cultivars and influence of preharvest hexanal treatment on their profiles. Can. J. Plant Sci. 95: 115–126. Biochemical changes of quality-determining components were evaluated in strawberry fruit subjected to preharvest spray treatments using a hexanal-containing formulation that is known to enhance shelf life and quality of fruits. Phenolic compounds and volatiles of fruits of four strawberry cultivars (Mira, Jewel, Kent, and St. Pierre) grown in southern Ontario were characterized by HPLC-MS and solid phase micro extraction (SPME) analysis. Qualitative and quantitative profiles of phenolic compounds varied among the cultivars. In all the cultivars, anthocyanins constituted the most prominent class of phenolic compounds. Volatile profiles of strawberry homogenate differed among the cultivars. Changes in phenolics and volatiles composition were determined in fruits of Mira and Jewel after spraying with a hexanal-containing formulation at weekly intervals. In Jewel, preharvest hexanal spraying altered the profiles of polyphenolic components, while minimal changes were noticed in Mira. Interestingly, very few differences were identified in ester profiles of treated and untreated Mira. In general, hexanal spray application resulted in a decrease in the abundance of several volatile components including esters, ketones, and lactones in treated Jewel compared with the control. The results suggest that cultivar-specific quality changes may result from a preharvest application of hexanal formulations, which may also imply different patterns of metabolite channeling and delay of fruit ripening processes.

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Faustini, Massimo, Giovanni Quintavalle Pastorino, Carla Colombani, Luca Maria Chiesa, Sara Panseri, Daniele Vigo et Giulio Curone. « Volatilome in Milk for Grana Padano and Parmigiano Reggiano Cheeses : A First Survey ». Veterinary Sciences 6, n^o 2 (9 mai 2019) : 41. http://dx.doi.org/10.3390/vetsci6020041.

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Milk characteristics in terms of volatile compounds can influence the subsequent product characteristics and can give indications about metabolism. These features can strongly depend on feeding and management. In this perspective, the screening of milk samples intended for Parmigiano-Reggiano and Grana Padano located in Northern Italy was performed, focusing on a panel of volatile molecules. The work was carried out on a total number of 25 bovine milk samples for the production of Parmigiano-Reggiano and Grana Padano. Milk samples were collected from May to September and analyzed for volatile molecules using headspace gas chromatography mass spectrometry. A range of several volatile molecule classes was considered (aldehydes, ketones, alcohols, carboxylic acids, esters, aromatic hydrocarbons, solforates). Results showed a significant influence of the month and destination of milk due to the time period and subsequent use in cheesemaking (Parmigiano-Reggiano and Grana Padano). Significant differences between months were observed for all volatiles. These preliminary results indicate differences between the two types of milk due to the period and destination. The study of volatile molecules in milk will give important information about the physiology of milk and the evolution of dairy products. These features must be extended and confirmed by the sensory analysis of milk and derived products, leading to a more complete characterization of milk biology and derived products.

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Masriany, Masriany, Rizkita R. Esyanti, Fenny M. Dwivany et Tjandra Anggraeni. « Banana Flower-Insect Interaction : Alpha-Pinene as Potential Attractant for the Insect Vector of Banana Blood Disease ». HAYATI Journal of Biosciences 27, n^o 1 (1 janvier 2020) : 8. http://dx.doi.org/10.4308/hjb.27.1.8.

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Volatile metabolites are produced by plants for self-defense and as communication mediators with the environment. Terpenes are volatiles emitted as odorant cues for herbivores and microorganisms. This study was aimed to investigate volatile metabolites produced by banana flowers that attract insect vectors of BBD. The volatile metabolites from banana flowers were extracted by headspace-solid phase microextraction (HS-SPME) and identified by gas chromatography–mass spectrometry (GC-MS). It was apparent that the concentrations of the metabolite alpha-pinene gradually increased from the first to the the third stage. Comparison of metabolites produced by symptomatic banana male flowers for BBD infection with non-symptomatic ones showed that the concentration of alpha-pinene was higher in symptomatic male flowers. In addition, preference for alpha-pinene was tested on three insect vector species (Rhodesiella bhutanensis, Drosophila sp., and Musca sp.), analyzed by M. Anova p<0.001, F(1.5) =12.539 and Duncan test. Results showed that the insect vectors were mostly attracted to 20 µl volume of alpha-pinene compared to the other volumes and that alpha-pinene functioned as an attractant to these insects. This research is important for the formulation of attractants for insect vectors of BBD to control transmission of banana blood disease.

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Issitt, Theo, Sean T. Sweeney, William J. Brackenbury et Kelly R. Redeker. « Sampling and Analysis of Low-Molecular-Weight Volatile Metabolites in Cellular Headspace and Mouse Breath ». Metabolites 12, n^o 7 (27 juin 2022) : 599. http://dx.doi.org/10.3390/metabo12070599.

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Volatile compounds, abundant in breath, can be used to accurately diagnose and monitor a range of medical conditions. This offers a noninvasive, low-cost approach with screening applications; however, the uptake of this diagnostic approach has been limited by conflicting published outcomes. Most published reports rely on large scale screening of the public, at single time points and without reference to ambient air. Here, we present a novel approach to volatile sampling from cellular headspace and mouse breath that incorporates multi-time-point analysis and ambient air subtraction revealing compound flux as an effective proxy of active metabolism. This approach to investigating breath volatiles offers a new avenue for disease biomarker discovery and diagnosis. Using gas chromatography mass spectrometry (GC/MS), we focus on low molecular weight, metabolic substrate/by-product compounds and demonstrate that this noninvasive technique is sensitive (reproducible at ~1 µg cellular protein, or ~500,000 cells) and capable of precisely determining cell type, status and treatment. Isolated cellular models represent components of larger mammalian systems, and we show that stress- and pathology-indicative compounds are detectable in mice, supporting further investigation using this methodology as a tool to identify volatile targets in human patients.

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Lee, Kyuwon, Seo-Hee Kwon, Sumin Song, Do-Yup Lee, Min Kyung Park et Young-Suk Kim. « Comparative Analysis of Volatile and Non-Volatile Metabolites Derived from Bacillus subtilis Strains Producing Different Levels of Biogenic Amines ». Metabolites 13, n^o 2 (2 février 2023) : 219. http://dx.doi.org/10.3390/metabo13020219.

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Biogenic amines (BAs), which are mainly generated by the microbial decarboxylation of amino acids, are important nitrogen compounds in fermented foods because of their toxicology. However, amino acids, the precursors of BAs, also play an important role in generating volatile and non-volatile metabolites, which are strongly associated with quality indicators for foods. Bacillus subtilis is one of dominant fermentative microorganism in various fermented foods and is well known as a BA-producing bacterium. In this study, B. subtilis strains which have different BAs-producing capacities, higher level of BAs production strain (BH) and lower level of BAs production strain (BL), were applied to compare the formations of volatile and non-volatile metabolite profiles according to cultivation times. In this study, histamine, putrescine, and spermidine were detected in all strains, however, 2-phenylethylamine was detected only in BH. Partial least squares discriminant analysis (PLS-DA) was applied to investigate the difference of metabolic profiles according to strains. In BH, some amino acids (phenylalanine, leucine, and threonine) and related volatile metabolites (3-methylbutanoic acid, pyrazines, styrene, and 1H-indole) were produced higher levels. On the other hand, BL produced significantly higher contents of metabolites associated with metabolism of fatty acids and nucleotides. It is necessary to consider the formation of metabolites in terms of quality as well as that of BAs during fermentation.

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Filipiak, Wojciech, Karol Jaroch, Paulina Szeliska, Karolina Żuchowska et Barbara Bojko. « Application of Thin-Film Microextraction to Analyze Volatile Metabolites in A549 Cancer Cells ». Metabolites 11, n^o 10 (14 octobre 2021) : 704. http://dx.doi.org/10.3390/metabo11100704.

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Volatile organic compounds (VOCs) have been proposed in the last two decades as biomarkers for disease detection and therapeutic monitoring. Model in vitro experiments with established cell lines are fundamental to clarify whether given VOCs originate from normal human cells or pathogens, including transformed cancer cells. Due to the trace concentrations of target metabolites, adsorptive enrichment is needed before gas chromatography-mass spectrometry (GC-MS) analysis, with solid-phase microextraction (SPME) being perfectly suited for this purpose. Here, a modification of SPME, the thin-film microextraction (TFME) technique, is proposed for analysis of cellular VOCs, which utilizes a planar mesh coated with stationary phase to increase the extraction phase volume and active surface area. In this study, four different adsorbents were compared: carboxen, divinylbenzene, hydrophobic−lipophilic balanced and polydimethylsiloxane. Amongst them, HLB sheets using poly(divinylbenzene-co-N-vinyl-pyrrolidone) skeleton structure proved to be the most versatile, enabling the most sensitive analysis of VOCs with a broad polarity and volatility. For HLB, sampling type (internal static headspace, external bi-directional headspace), extraction temperature and extraction time were also examined. An established method was successfully applied to analyze metabolites produced by A549 cells revealing five volatiles at significantly higher (additionally benzaldehyde at lower) levels in cell culture medium compared to the cell-free reference medium headspace.

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Kharasch, Evan D., Jesara L. Schroeder, H. Denny Liggitt, Dustin Ensign et Dale Whittington. « New Insights into the Mechanism of Methoxyflurane Nephrotoxicity and Implications for Anesthetic Development (Part 2) ». Anesthesiology 105, n^o 4 (1 octobre 2006) : 737–45. http://dx.doi.org/10.1097/00000542-200610000-00020.

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Background Methoxyflurane nephrotoxicity results from its metabolism, which occurs by both dechlorination (to methoxydifluoroacetic acid [MDFA]) and O-demethylation (to fluoride and dichloroacetic acid [DCAA]). Inorganic fluoride can be toxic, but it remains unknown why other anesthetics, commensurately increasing systemic fluoride concentrations, are not toxic. Fluoride is one of many methoxyflurane metabolites and may itself cause toxicity and/or reflect formation of other toxic metabolite(s). This investigation evaluated the disposition and renal effects of known methoxyflurane metabolites. Methods Rats were given by intraperitoneal injection the methoxyflurane metabolites MDFA, DCAA, or sodium fluoride (0.22, 0.45, 0.9, or 1.8 mmol/kg followed by 0.11, 0.22, 0.45, or 0.9 mmol/kg on the next 3 days) at doses relevant to metabolite exposure after methoxyflurane anesthesia, or DCAA and fluoride in combination. Renal histology and function (blood urea nitrogen, urine volume, urine osmolality) and metabolite excretion in urine were assessed. Results Methoxyflurane metabolite excretion in urine after injection approximated that after methoxyflurane anesthesia, confirming the appropriateness of metabolite doses. Neither MDFA nor DCAA alone had any effects on renal function parameters or necrosis. Fluoride at low doses (0.22, then 0.11 mmol/kg) decreased osmolality, whereas higher doses (0.45, then 0.22 mmol/kg) also caused diuresis but not significant necrosis. Fluoride and DCAA together caused significantly greater tubular cell necrosis than fluoride alone. Conclusions Methoxyflurane nephrotoxicity seems to result from O-demethylation, which forms both fluoride and DCAA. Because their co-formation is unique to methoxyflurane compared with other volatile anesthetics and they are more toxic than fluoride alone, this suggests a new hypothesis of methoxyflurane nephrotoxicity. This may explain why increased fluoride formation from methoxyflurane, but not other anesthetics, is associated with toxicity. These results may have implications for the interpretation of clinical anesthetic defluorination, use of volatile anesthetics, and the laboratory methods used to evaluate potential anesthetic toxicity.

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Pinto, Joana, Ângela Carapito, Filipa Amaro, Ana Rita Lima, Carina Carvalho-Maia, Maria Conceição Martins, Carmen Jerónimo, Rui Henrique, Maria de Lourdes Bastos et Paula Guedes de Pinho. « Discovery of Volatile Biomarkers for Bladder Cancer Detection and Staging through Urine Metabolomics ». Metabolites 11, n^o 4 (26 mars 2021) : 199. http://dx.doi.org/10.3390/metabo11040199.

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Timely diagnosis is crucial to improve the long-term survival of bladder cancer (BC) patients. The discovery of new BC biomarkers based in urine analysis is very attractive because this biofluid is in direct contact with the inner bladder layer, in which most of the neoplasms develop, and is non-invasively collected. Hence, this work aimed to unveil alterations in the urinary volatile profile of patients diagnosed with BC compared with cancer-free individuals, as well as differences among patients diagnosed at different tumor stages, to identify candidate biomarkers for non-invasive BC diagnosis and staging. Urine analysis was performed by headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry (HS-SPME-GC-MS). The results unveiled that BC patients have a distinct urinary volatile profile characterized by higher levels of several alkanes and aromatic compounds, and lower levels of aldehydes, ketones and monoterpenes. Seventeen significantly altered volatiles were used to evaluate the performance for overall BC detection, disclosing 70% sensitivity, 89% specificity and 80% accuracy. Moreover, distinct urinary volatile profiles were found among patients diagnosed at different tumor stages (Ta/Tis, T1 and ≥T2). This work identified distinct urinary volatile signatures of BC patients with potential for non-invasive detection and staging of bladder cancer.

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Davies, HL, et JL Hill. « The effect of diet on the metabolism in sheep of the tritiated isoflavones formononetin and biochanin A ». Australian Journal of Agricultural Research 40, n^o 1 (1989) : 157. http://dx.doi.org/10.1071/ar9890157.

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The metabolism of tritiated formononetin was studied in vivo and in vitro in the sheep and the metabolism of biochanin A studied in vitro.In vivo. Most of the formononetin was metabolized to equol and 81% of the administered radioactivity was excreted in the urine within 48 h, the main component being equol. Little or no daidzein was found in either rumen, plasma or urine samples. Some metabolites appeared on the TLC chromatograms in small amounts (never more than 10%); these were probably desmethylangolensin and O-methylequol, and their role in isoflavone metabolism is unknown.In vitro. The rate of metabolism of formononetin and biochanin A added to rumen samples from sheep varied with diet, being more rapid in samples from sheep fed on lucerne chaff or clover. Formononetin was converted to equol. Biochanin A was converted to genistein in rumen liquor from sheep fed on oaten chaff, but was further metabolized if the sheep had been fed on clover. A metabolite of RF 0.1 was observed which with a longer incubation time was converted to a non-volatile compound at RF 0.9.

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Zou, Jing, Yinghong Hu, Kuo Li, Yang Liu, Miao Li, Xinyuan Pan et Xuedong Chang. « Chestnuts in Fermented Rice Beverages Increase Metabolite Diversity and Antioxidant Activity While Reducing Cellular Oxidative Damage ». Foods 12, n^o 1 (28 décembre 2022) : 164. http://dx.doi.org/10.3390/foods12010164.

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Foods containing chestnuts (Castanea mollissima Blume) are relatively uncommon, despite the high nutrient and starch contents and purported health benefits. In this study, we examine the flavor-related metabolites, volatile compounds, and amino acids in a traditional glutinous rice fermented beverage supplemented with chestnuts as a fermentation substrate for lactic acid bacteria (LAB). Changes in antioxidant activity towards free radicals and effects on cellular oxidative stress are compared between beverages with or without chestnuts. The fermented chestnut-rice beverage (FCRB) has higher sensory scores and a wider range of volatiles and flavor-related compounds (74 vs. 38 species compounds), but lower amino acid contents, than the traditional fermented glutinous rice beverage (TFRB). In free radical scavenging assays, the FCRB exhibits higher activity than the TFRB in vitro. Furthermore, while neither beverage induces cytotoxity in Caco-2 cells at concentrations up to 2 mg/mL, pretreatment with the FCRB results in lower rates of apoptosis and necrosis and higher overall viability in cells with H2O2-induced oxidative stress compared to pretreatment with the TFRB. The enhanced reactive oxygen species neutralization in vitro and protection against oxidative damage in cells, coupled with increased diversity of volatiles and flavor-related metabolites of LAB, support the addition of chestnuts to enhance flavor profile and antioxidant properties of fermented functional foods.

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Oliveira, J. M., P. Oliveira, R. L. Baumes et M. O. Maia. « Volatile and Glycosidically Bound Composition of Loureiro and Alvarinho Wines ». Food Science and Technology International 14, n^o 4 (août 2008) : 341–53. http://dx.doi.org/10.1177/1082013208097442.

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Composition of Loureiro and Alvarinho wines from the Vinhos Verdes region, regarding free volatile compounds as well as glycosidically bound aroma precursors, was exhaustively determined by gas chromatography—mass spectrometry after adsorption on XAD-2 resin. On the whole, were identified and quantified 120 volatile compounds in the free fraction and 77 glycosidically bound compounds, belonging to C6-compounds, alcohols, fatty acids ethyl esters, esters of organic acids, acetates, monoterpenic alcohols, monoterpenic oxides and diols, C13-norisoprenoids, volatile phenols, volatile fatty acids, and carbonyl compounds. Globally, the wines of the two cultivars present similar composition on volatiles. However, regarding varietal compounds, Loureiro wines were richer than Alvarinho ones with respect to C6-compounds and monoterpenic compounds, occurring the opposite for volatile phenols. It was also demonstrated that wines of both varieties might benefit the aroma reserve, present as glycoconjugates, as it is susceptible of being technologically explored. Linalool, Ho-trienol, (α-terpineol, contributing with fruity and floral notes, and (β-damascenone mostly for Alvarinho, confering tropical fruit notes, are the varietal compounds which may particularly influence the aroma of these wines. Respecting fermentative compounds, Alvarinho is also particularly rich in fatty acids ethyl esters related to lipid metabolism and acetates of fusel alcohols, which can provide it a fruity character; Loureiro contains higher levels of esters of organic acids and 2-phenylethanol, conferring fruity and floral notes. Sensory analysis agreed with chemical analyses showing a pronounced tree and tropical fruit character for Alvarinho wines while Loureiro wines present more intense citrus fruit notes.

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Selvam et Björnstedt. « A Novel Assay Method to Determine the β-Elimination of Se-Methylselenocysteine to Monomethylselenol by Kynurenine Aminotransferase 1 ». Antioxidants 9, n^o 2 (5 février 2020) : 139. http://dx.doi.org/10.3390/antiox9020139.

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Kynurenine aminotransferase 1 (KYAT1 or CCBL1) plays a major role in Se-methylselenocysteine (MSC) metabolism. It is a bi-functional enzyme that catalyzes transamination and beta-elimination activity with a single substrate. KYAT1 produces methylselenol (CH3SeH) via β-elimination activities with MSC as a substrate. This methylated selenium compound is a major cytotoxic selenium metabolite, causing apoptosis in a wide variety of cancer cells. Methylselenol is volatile and possesses extraordinary nucleophilic properties. We herein describe a simple spectrophotometric assay by combining KYAT1 and thioredoxin reductase (TrxR) to detect CH3SeH in a coupled activity assay. The metabolite methylselenol and its oxidized form from MSC metabolism is utilized as a substrate for TrxR1 and this can be monitored spectroscopically at 340 nm. Our results show the feasibility of monitoring the β-elimination of KYAT1 by our assay and the results were compared to the previously described β-elimination assays measuring pyruvate. By using known inhibitors of KYAT1 and TrxR1, we further validated the respective reaction. Our data provide a simple but accurate method to determine the β-elimination activity of KYAT1, which is of importance for mechanistic studies of a highly interesting selenium compound.

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Sá, Carina, Diana Matos, Paulo Cardoso et Etelvina Figueira. « Do Volatiles Affect Bacteria and Plants in the Same Way ? Growth and Biochemical Response of Non-Stressed and Cd-Stressed Arabidopsis thaliana and Rhizobium E20-8 ». Antioxidants 11, n^o 11 (21 novembre 2022) : 2303. http://dx.doi.org/10.3390/antiox11112303.

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Plant roots are colonized by rhizobacteria, and these soil microorganisms can not only stimulate plant growth but also increase tolerance to stress through the production of volatile organic compounds. However, little is known about the effect that these plant beneficial volatiles may have on bacteria. In this study, the effects on growth and oxidative status of different concentrations of three volatiles already reported to have a positive influence on plant growth (2-butanone, 3-methyl-1-butanol, and 2,3-butanediol) were determined in A. thaliana and Rhizobium sp. strain E20-8 via airborne exposure in the presence and absence of Cd. It was expected to ascertain if the plant and the bacterium are influenced in the same way by the volatiles, and if exposure to stress (Cd) shifts the effects of volatiles on plants and bacteria. Results showed the antioxidant activity of the volatiles protecting the plant cell metabolism from Cd toxicity and increasing plant tolerance to Cd. Effects on bacteria were less positive. The two alcohols (3-methyl-1-butanol and 2,3-butanediol) increased Cd toxicity, and the ketone (2-butanone) was able to protect Rhizobium from Cd stress, constituting an alternative way to protect soil bacterial communities from stress. The application of 2-butanone thus emerges as an alternative way to increase crop production and crop resilience to stress in a more sustainable way, either directly or through the enhancement of PGPR activity.

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Wu, Qixian, Huijun Gao, Zhengke Zhang, Taotao Li, Hongxia Qu, Yueming Jiang et Ze Yun. « Deciphering the Metabolic Pathways of Pitaya Peel after Postharvest Red Light Irradiation ». Metabolites 10, n^o 3 (14 mars 2020) : 108. http://dx.doi.org/10.3390/metabo10030108.

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Red light irradiation can effectively prolong the shelf-life of many fruit. However, little is known about red light-induced metabolite and enzyme activities. In this study, pitaya fruit was treated with 100 Lux red light for 24 h. Red light irradiation significantly attenuated the variation trend of senescence traits, such as the decrease of total soluble solid (TSS) and TSS/acidity (titratable acidity, TA) ratio, the increase of TA, and respiratory rate. In addition, the reactive oxygen species (ROS) related characters, primary metabolites profiling, and volatile compounds profiling were determined. A total of 71 primary metabolites and 67 volatile compounds were detected and successfully identified by using gas chromatography mass spectrometry (GC-MS). Red light irradiation enhanced glycolysis, tricarboxylic acid (TCA) cycle, aldehydes metabolism, and antioxidant enzymes activities at early stage of postharvest storage, leading to the reduction of H2O2, soluble sugars, organic acids, and C-6 and C-7 aldehydes. At a later stage of postharvest storage, a larger number of resistance-related metabolites and enzyme activities were induced in red light-treated pitaya peel, such as superoxide dismutase (SOD), ascorbate peroxidase (APX), 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radical-scavenging, reducing power, fatty acids, and volatile aroma.

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Pan, D. D., Z. Wu, T. Peng, X. Q. Zeng et H. Li. « Volatile organic compounds profile during milk fermentation by Lactobacillus pentosus and correlations between volatiles flavor and carbohydrate metabolism ». Journal of Dairy Science 97, n^o 2 (février 2014) : 624–31. http://dx.doi.org/10.3168/jds.2013-7131.

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Shin, Minhye, Jeong-Won Kim, Bonbin Gu, Sooah Kim, Hojin Kim, Won-Chan Kim, Mee-Ryung Lee et Soo-Rin Kim. « Comparative Metabolite Profiling of Traditional and Commercial Vinegars in Korea ». Metabolites 11, n^o 8 (24 juillet 2021) : 478. http://dx.doi.org/10.3390/metabo11080478.

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Vinegar, composed of various organic acids, amino acids, and volatile compounds, has been newly recognized as a functional food with health benefits. Vinegar is produced through alcoholic fermentation of various raw materials followed by acetic acid fermentation, and detailed processes greatly vary between different vinegar products. This study performed metabolite profiling of various vinegar products using gas chromatography–mass spectrometry to identify metabolites that are specific to vinegar production processes. In particular, seven traditional vinegars that underwent spontaneous and slow alcoholic and acetic acid fermentations were compared to four commercial vinegars that were produced through fast acetic acid fermentation using distilled ethanol. A total of 102 volatile and 78 nonvolatile compounds were detected, and the principal component analysis of metabolites clearly distinguished between the traditional and commercial vinegars. Ten metabolites were identified as specific or significantly different compounds depending on vinegar production processes, most of which had originated from complex microbial metabolism during traditional vinegar fermentation. These process-specific compounds of vinegars may serve as potential biomarkers for fermentation process controls as well as authenticity and quality evaluation.

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H.J. Lee, Jisun, Henry O. Awika, Guddadarangavvanahally K. Jayaprakasha, Carlos A. Avila, Kevin M. Crosby et Bhimanagouda S. Patil. « Tomato Metabolic Changes in Response to Tomato-Potato Psyllid (Bactericera cockerelli) and Its Vectored Pathogen Candidatus Liberibacter solanacearum ». Plants 9, n^o 9 (6 septembre 2020) : 1154. http://dx.doi.org/10.3390/plants9091154.

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The bacterial pathogen ‘Candidatus Liberibacter solanacearum’ (Lso) is transmitted by the tomato potato psyllid (TPP), Bactericera cockerelli, to solanaceous crops. In the present study, the changes in metabolic profiles of insect-susceptible (cv CastleMart) and resistant (RIL LA3952) tomato plants in response to TPP vectoring Lso or not, were examined after 48 h post infestation. Non-volatile and volatile metabolites were identified and quantified using headspace solid-phase microextraction equipped with a gas chromatograph-mass spectrometry (HS-SPME/GC-MS) and ultra-high pressure liquid chromatography coupled to electrospray quadrupole time-of-flight mass spectrometry (UPLC/ESI-HR-QTOFMS), respectively. Partial least squares-discriminant analysis (PLS-DA) was used to define the major uncorrelated metabolite components assuming the treatments as the correlated predictors. Metabolic changes in various classes of metabolites, including volatiles, hormones, and phenolics, were observed in resistant and susceptible plants in response to the insects carrying the pathogen or not. The results suggest the involvement of differentially regulated and, in some cases, implicates antagonistic metabolites in plant defensive signaling. Upon validation, the identified metabolites could be used as markers to screen and select breeding lines with enhanced resistance to reduce economic losses due to the TPP-Lso vector-pathogen complex in Solanaceous crops.

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Lamoureux, G. L., D. G. Rusness et P. Schroder. « Metabolism of a Diphenylether Herbicide to a Volatile Thioanisole and a Polar Sulfonic Acid Metabolite in Spruce (Picea) ». Pesticide Biochemistry and Physiology 47, n^o 1 (septembre 1993) : 8–20. http://dx.doi.org/10.1006/pest.1993.1058.

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Ollivier, Patrick R. L., Andrew S. Bahrou, Sarah Marcus, Talisha Cox, Thomas M. Church et Thomas E. Hanson. « Volatilization and Precipitation of Tellurium by Aerobic, Tellurite-Resistant Marine Microbes ». Applied and Environmental Microbiology 74, n^o 23 (10 octobre 2008) : 7163–73. http://dx.doi.org/10.1128/aem.00733-08.

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ABSTRACT Microbial resistance to tellurite, an oxyanion of tellurium, is widespread in the biosphere, but the geochemical significance of this trait is poorly understood. As some tellurite resistance markers appear to mediate the formation of volatile tellurides, the potential contribution of tellurite-resistant microbial strains to trace element volatilization in salt marsh sediments was evaluated. Microbial strains were isolated aerobically on the basis of tellurite resistance and subsequently examined for their capacity to volatilize tellurium in pure cultures. The tellurite-resistant strains recovered were either yeasts related to marine isolates of Rhodotorula spp. or gram-positive bacteria related to marine strains within the family Bacillaceae based on rRNA gene sequence comparisons. Most strains produced volatile tellurides, primarily dimethyltelluride, though there was a wide range of the types and amounts of species produced. For example, the Rhodotorula spp. produced the greatest quantities and highest diversity of volatile tellurium compounds. All strains also produced methylated sulfur compounds, primarily dimethyldisulfide. Intracellular tellurium precipitates were a major product of tellurite metabolism in all strains tested, with nearly complete recovery of the tellurite initially provided to cultures as a precipitate. Different strains appeared to produce different shapes and sizes of tellurium containing nanostructures. These studies suggest that aerobic marine yeast and Bacillus spp. may play a greater role in trace element biogeochemistry than has been previously assumed, though additional work is needed to further define and quantify their specific contributions.

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Brock, Nelson L., Christian A. Citron, Claudia Zell, Martine Berger, Irene Wagner-Döbler, Jörn Petersen, Thorsten Brinkhoff, Meinhard Simon et Jeroen S. Dickschat. « Isotopically labeled sulfur compounds and synthetic selenium and tellurium analogues to study sulfur metabolism in marine bacteria ». Beilstein Journal of Organic Chemistry 9 (15 mai 2013) : 942–50. http://dx.doi.org/10.3762/bjoc.9.108.

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Members of the marine Roseobacter clade can degrade dimethylsulfoniopropionate (DMSP) via competing pathways releasing either methanethiol (MeSH) or dimethyl sulfide (DMS). Deuterium-labeled [2H6]DMSP and the synthetic DMSP analogue dimethyltelluriopropionate (DMTeP) were used in feeding experiments with the Roseobacter clade members Phaeobacter gallaeciensis DSM 17395 and Ruegeria pomeroyi DSS-3, and their volatile metabolites were analyzed by closed-loop stripping and solid-phase microextraction coupled to GC–MS. Feeding experiments with [2H6]DMSP resulted in the incorporation of a deuterium label into MeSH and DMS. Knockout of relevant genes from the known DMSP demethylation pathway to MeSH showed in both species a residual production of [2H3]MeSH, suggesting that a second demethylation pathway is active. The role of DMSP degradation pathways for MeSH and DMS formation was further investigated by using the synthetic analogue DMTeP as a probe in feeding experiments with the wild-type strain and knockout mutants. Feeding of DMTeP to the R. pomeroyi knockout mutant resulted in a diminished, but not abolished production of demethylation pathway products. These results further corroborated the proposed second demethylation activity in R. pomeroyi. Isotopically labeled [2H3]methionine and 34SO4 2−, synthesized from elemental 34S8, were tested to identify alternative sulfur sources besides DMSP for the MeSH production in P. gallaeciensis. Methionine proved to be a viable sulfur source for the MeSH volatiles, whereas incorporation of labeling from sulfate was not observed. Moreover, the utilization of selenite and selenate salts by marine alphaproteobacteria for the production of methylated selenium volatiles was explored and resulted in the production of numerous methaneselenol-derived volatiles via reduction and methylation. The pathway of selenate/selenite reduction, however, proved to be strictly separated from sulfate reduction.

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Hébert, Agnès, Marie-Pierre Forquin-Gomez, Aurélie Roux, Julie Aubert, Christophe Junot, Jean-François Heilier, Sophie Landaud, Pascal Bonnarme et Jean-Marie Beckerich. « New Insights into Sulfur Metabolism in Yeasts as Revealed by Studies of Yarrowia lipolytica ». Applied and Environmental Microbiology 79, n^o 4 (7 décembre 2012) : 1200–1211. http://dx.doi.org/10.1128/aem.03259-12.

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ABSTRACTYarrowia lipolytica, located at the frontier of hemiascomycetous yeasts and fungi, is an excellent candidate for studies of metabolism evolution. This yeast, widely recognized for its technological applications, in particular produces volatile sulfur compounds (VSCs) that fully contribute to the flavor of smear cheese. We report here a relevant global vision of sulfur metabolism inY. lipolyticabased on a comparison between high- and low-sulfur source supplies (sulfate, methionine, or cystine) by combined approaches (transcriptomics, metabolite profiling, and VSC analysis). The strongest repression of the sulfate assimilation pathway was observed in the case of high methionine supply, together with a large accumulation of sulfur intermediates. A high sulfate supply seems to provoke considerable cellular stress via sulfite production, resulting in a decrease of the availability of the glutathione pathway's sulfur intermediates. The most limited effect was observed for the cystine supply, suggesting that the intracellular cysteine level is more controlled than that of methionine and sulfate. Using a combination of metabolomic profiling and genetic experiments, we revealed taurine and hypotaurine metabolism in yeast for the first time. On the basis of a phylogenetic study, we then demonstrated that this pathway was lost by some of the hemiascomycetous yeasts during evolution.

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HIRAKAWA, KATAHISA. « Metabolism and organ derangement of volatile anesthetics. » JOURNAL OF JAPAN SOCIETY FOR CLINICAL ANESTHESIA 13, n^o 6 (1993) : 504–14. http://dx.doi.org/10.2199/jjsca.13.504.

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Liu, Yu, Hui Zhang, Shivshankar Umashankar, Xu Liang, Hui Lee, Sanjay Swarup et Choon Ong. « Characterization of Plant Volatiles Reveals Distinct Metabolic Profiles and Pathways among 12 Brassicaceae Vegetables ». Metabolites 8, n^o 4 (14 décembre 2018) : 94. http://dx.doi.org/10.3390/metabo8040094.

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Plants emit characteristic organic volatile compounds (VOCs) with diverse biological/ecological functions. However, the links between plant species/varieties and their phytochemical emission profiles remain elusive. Here, we developed a direct headspace solid-phase microextraction (HS-SPME) technique and combined with non-targeted gas chromatography‒high-resolution mass spectrometry (GC-HRMS) platform to investigate the VOCs profiles of 12 common Brassicaceae vegetables (watercress, rocket, Brussels sprouts, broccoli, kai lan, choy sum, pak choi, cabbage, Chinese cabbage, cauliflower, radish and cherry radish). The direct HS-SPME sampling approach enabled reproducible capture of the rapid-emitting VOCs upon plant tissue disruption. The results revealed extensive variation in VOCs profiles among the 12 Brassicaceae vegetables. Furthermore, principal component analysis (PCA) showed that the VOC profiles could clearly distinguish the 12 Brassicaceae vegetables, and that these profiles well reflected the classical morphological classification. After multivariate statistical analysis, 44 VOCs with significant differences among the Brassicaceae vegetables were identified. Pathway analysis showed that three secondary metabolism pathways, including the fatty acid pathway, methylerythritol phosphate (MEP) pathway and glucosinolate (GLS) pathway, behave distinctively in these vegetables. These three pathways are responsible for the generation and emission of green leaf volatiles (GLVs), terpenes and isothiocyanates (ITCs), respectively. Correlation analysis further showed that volatile metabolites formed via the common pathway had significantly positive correlations, whereas metabolites from different pathways had either non-significant or significantly negative correlations. Genetic influences on these metabolites across various vegetable types were also evaluated. These findings extend our phytochemical knowledge of the 12 edible Brassicaceae vegetables and provide useful information on their secondary metabolism.

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Liu, Tongjie, Yixin Shi, Yang Li, Huaxi Yi, Pimin Gong, Kai Lin, Zhe Zhang et Lanwei Zhang. « The Mutual Influence of Predominant Microbes in Sourdough Fermentation : Focusing on Flavor Formation and Gene Transcription ». Foods 11, n^o 15 (8 août 2022) : 2373. http://dx.doi.org/10.3390/foods11152373.

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The interplay between microorganisms generally plays a vital role in food fermentation. In this study, the mutual influence of Saccharomyces cerevisiae and Fructilactobacillus sanfranciscensis, the two predominant microbes in the sourdough ecosystem, were investigated in situ during fermentation. Doughs fermented with S. cerevisiae, F. sanfranciscensis, or their combination were compared regarding acid production, microbial density, and volatiles. Furthermore, in situ gene expressions were investigated using RNA-sequencing. The results showed that the presence of S. cerevisiae had no visible influence on F. sanfranciscensis, whereas F. sanfranciscensis facilitated the growth of S. cerevisiae but affected its volatile production since metabolites such as 3-methyl-1-butanol decreased. The RNA-sequencing demonstrated that S. cerevisiae significantly changed the gene transcripts implicated in amino acid metabolism in F. sanfranciscensis and may stimulate its growth suggested by the enrichment of the KEGG pathway of peptidoglycan biosynthesis.

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Zaman, Rashaduz, Courtney May, Aziz Ullah et Nadir Erbilgin. « Bark Beetles Utilize Ophiostomatoid Fungi to Circumvent Host Tree Defenses ». Metabolites 13, n^o 2 (6 février 2023) : 239. http://dx.doi.org/10.3390/metabo13020239.

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Bark beetles maintain symbiotic associations with a diversity of microbial organisms, including ophiostomatoid fungi. Studies have frequently reported the role of ophiostomatoid fungi in bark beetle biology, but how fungal symbionts interact with host chemical defenses over time is needed. We first investigated how inoculations by three fungal symbionts of mountain pine beetle affect the terpene chemistry of live lodgepole pine trees. We then conducted a complimentary laboratory experiment specifically measuring the host metabolite degradation by fungi and collected the fungal organic volatiles following inoculations with the same fungal species on lodgepole pine logs. In both experiments, we analyzed the infected tissues for their terpene chemistry. Additionally, we conducted an olfactometer assay to determine whether adult beetles respond to the volatile organic chemicals emitted from each of the three fungal species. We found that all fungi upregulated terpenes as early as two weeks after inoculations. Similarly, oxygenated monoterpene concentrations also increased by several folds (only in logs). A large majority of beetles tested showed a strong attraction to two fungal species, whereas the other fungus repelled the beetles. Together this study shows that fungal symbionts can alter host defense chemistry, assist beetles in overcoming metabolite toxicity, and provide possible chemical cues for bark beetle attraction.

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