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1.
J Chromatogr A ; 1626: 461369, 2020 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-32797848

RESUMO

Pumped sorbent tube sampling is a well established method for the sampling of volatile organic compounds (VOCs) and semi volatile organic compounds (SVOCs) in ambient, indoor and workplace atmospheres1. Safe sampling volumes and breakthrough volumes have been published for commonly found VOCs on widely used sorbents such as Tenax, however for newer sorbents and less commonly found VOCs there is less robust data. The Safe Sampling Volumes (SSVs) were determined from 15 tests of Retention Volume on 12 VOCs across the 3 sorbents. VOCs tested were: Aldehydes (C5, C6, C8, C9), Ketones (C4, C6), Alcohols (C3, C4), Furan, Limonene, Isoprene and Ethyl Acetate. 12 VOC / sorbent combinations gave SSVs large enough for practical sampling of indoor atmospheres, while SSVs for Furan on Carbopack-X, Isovaleraldehyde on Tenax TA and Methyl Ethyl Ketone on Tenax TA gave SSVs that were too small to be of practical use. This work identifies suitable sorbents and sampling volumes for the complete range of species tested.


Assuntos
Cromatografia Gasosa/métodos , Polímeros/química , Compostos Orgânicos Voláteis/análise , Adsorção , Poluição do Ar em Ambientes Fechados/análise , Aldeídos/química , Monitoramento Ambiental , Furanos/química , Compostos Orgânicos Voláteis/química
2.
Nat Commun ; 11(1): 2706, 2020 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-32483217

RESUMO

Aldehyde is one of most synthetically versatile functional groups and can participate in numerous chemical transformations. While a variety of simple aromatic aldehydes are commercially available, those with a more complex substitution pattern are often difficult to obtain. Benzylic oxygenation of methylarenes is a highly attractive method for aldehyde synthesis as the starting materials are easy to obtain and handle. However, regioselective oxidation of functionalized methylarenes, especially those that contain heterocyclic moieties, to aromatic aldehydes remains a significant challenge. Here we show an efficient electrochemical method that achieves site-selective electrooxidation of methyl benzoheterocycles to aromatic acetals without using chemical oxidants or transition-metal catalysts. The acetals can be converted to the corresponding aldehydes through hydrolysis in one-pot or in a separate step. The synthetic utility of our method is highlighted by its application to the efficient preparation of the antihypertensive drug telmisartan.


Assuntos
Acetais/química , Aldeídos/química , Técnicas Eletroquímicas/métodos , Hidrocarbonetos Aromáticos/química , Modelos Químicos , Acetais/síntese química , Aldeídos/síntese química , Amidinas/química , Benzimidazóis/química , Catálise , Hidrocarbonetos Aromáticos/síntese química , Hidrólise , Estrutura Molecular , Oxidantes/química , Oxirredução
3.
Food Chem ; 324: 126898, 2020 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-32361096

RESUMO

Reactions involving reactive carbonyls, creatinine, and ammonia-producing compounds were investigated in order to clarify the formation of the heterocyclic aromatic amine (HAA) 2-amino-3,4-dimethylimidazo(4,5-f)quinoline (MeIQ). Obtained results showed that MeIQ was only produced when 2-butenal (crotonaldehyde) was present. Reaction yields depended on the pH, with a maximum around pH 6.5, and on concentrations of crotonaldehyde and creatinine. Ammonia was also required for MeIQ formation, but ammonia was produced by creatinine decomposition. The amount of MeIQ formed increased with reaction time, temperature, and oxygen content in the reaction atmosphere. Activation energy for MeIQ formation from crotonaldehyde, creatinine, and glutamine was 72.2 ± 0.4 kJ·mol-1. A reaction pathway that explains MeIQ formation is proposed. Obtained results suggest a main role of reactive carbonyls formed in foods (the food carbonylome) on HAA formation. In addition, they provide scientific basis for the understanding of how HAAs are formed and could be mitigated.


Assuntos
Aldeídos/química , Creatinina/química , Quinolinas/química , Amônia/química , Cromatografia Líquida de Alta Pressão , Compostos Heterocíclicos/química , Concentração de Íons de Hidrogênio , Oxigênio/química , Quinolinas/análise , Espectrometria de Massas em Tandem , Temperatura
4.
Food Chem ; 327: 127031, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32464458

RESUMO

The 1,2-dicarbonyl compounds have received extensive attention due to their high reactivity and toxicity in vitro and in vivo. Availability of scavenging compounds may facilitate development of efficient strategies for their control. The concept of in situ generation of carbonyl trapping agents is an intriguing proposition and has been demonstrated with amino acid tryptophan. Ability of indole to undergo electrophilic aromatic substitution reaction was studied in the past with methylglyoxal. To confirm the generality of this reaction, model systems containing indole and several 1,2-dicarbonyl compounds were prepared and reacted at room temperature (RT) and at 150 °C and analyzed by ESI-qTOF-MS/MS and isotopic labeling technique. Indole showed ability to capture all the tested 1,2-dicarbonyls. Longer chain 1,2-dicarbonyls showed higher temperature dependency than shorter chain in their reactivity towards indole. Furthermore, the ability of indole to scavenge Strecker aldehydes was also demonstrated in alanine/glucose and in a bread model systems using [13C-2]indole.


Assuntos
Aldeídos/química , Indóis/química , Pão/análise , Temperatura , Triptofano/química
5.
Food Chem ; 321: 126603, 2020 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-32244142

RESUMO

The formation of 4-hydroxy-2-hexenal (HHE) and 4-hydroxy-2-nonenal (HNE) in vegetable oils and model oil systems were quantitatively assessed by RP-HPLC. Regardless of heating temperature, HHE was only detected in rapeseed and linseed oil, while HNE was detected in all tested oils. Intrinsic tocopherols suppressed HHE/HNE formation, but with similar inhibition rates (10.49-16.04%). Linear correlations were observed between HHE/HNE contents and corresponding n-3/6 fatty acid content in oils (R2 = 0.989/0.971). Model oil system revealed that HHE/HNE formation was closely related to methyl linolenate (MLN) and methyl linoleate (ML) contents. Low levels of ML (<0.5%) and MLN (<1.0%) did not lead to HHE/HNE formation. Therefore, HHE/HNE was classified as the characteristic aldehydes of n-3 and n-6 type oils, respectively. Heat map evaluation and regression analysis indicated HHE could predict the n-3 type oils oxidation, while HNE was a good indicator to estimate the oxidative deterioration of n-6 and n-9 type oils.


Assuntos
Aldeídos/química , Gorduras Insaturadas/química , Óleos Vegetais/química , Cromatografia Líquida de Alta Pressão , Ácidos Graxos/química , Temperatura Alta , Oxirredução , Tocoferóis/química
6.
Nature ; 581(7809): 415-420, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32268340

RESUMO

The ubiquity of tertiary alkylamines in pharmaceutical and agrochemical agents, natural products and small-molecule biological probes1,2 has stimulated efforts towards their streamlined synthesis3-9. Arguably the most robust method for the synthesis of tertiary alkylamines is carbonyl reductive amination3, which comprises two elementary steps: the condensation of a secondary alkylamine with an aliphatic aldehyde to form an all-alkyl-iminium ion, which is subsequently reduced by a hydride reagent. Direct strategies have been sought for a 'higher order' variant of this reaction via the coupling of an alkyl fragment with an alkyl-iminium ion that is generated in situ10-14. However, despite extensive efforts, the successful realization of a 'carbonyl alkylative amination' has not yet been achieved. Here we present a practical and general synthesis of tertiary alkylamines through the addition of alkyl radicals to all-alkyl-iminium ions. The process is facilitated by visible light and a silane reducing agent, which trigger a distinct radical initiation step to establish a chain process. This operationally straightforward, metal-free and modular transformation forms tertiary amines, without structural constraint, via the coupling of aldehydes and secondary amines with alkyl halides. The structural and functional diversity of these readily available precursors provides a versatile and flexible strategy for the streamlined synthesis of complex tertiary amines.


Assuntos
Aminas/química , Aminas/síntese química , Técnicas de Química Sintética/métodos , Aldeídos/química , Alquilação , Aminação , Loratadina/análogos & derivados , Loratadina/síntese química , Loratadina/química
7.
Nat Commun ; 11(1): 1956, 2020 04 23.
Artigo em Inglês | MEDLINE | ID: mdl-32327665

RESUMO

The dehydrogenative alkenylation of C-H bonds with alkenes represents an atom- and step-economical approach for olefin synthesis and molecular editing. Site-selective alkenylation of alkanes and aldehydes with the C-H substrate as the limiting reagent holds significant synthetic value. We herein report a photocatalytic method for the direct alkenylation of alkanes and aldehydes with aryl alkenes in the absence of any external oxidant. A diverse range of commodity feedstocks and pharmaceutical compounds are smoothly alkenylated in useful yields with the C-H partner as the limiting reagent. The late-stage alkenylation of complex molecules occurs with high levels of site selectivity for sterically accessible and electron-rich C-H bonds. This strategy relies on the synergistic combination of direct hydrogen atom transfer photocatalysis with cobaloxime-mediated hydrogen-evolution cross-coupling, which promises to inspire additional perspectives for selective C-H functionalizations in a green manner.


Assuntos
Aldeídos/química , Alcanos/química , Alcenos/química , Alcenos/síntese química , Catálise , Técnicas de Química Sintética , Química Verde , Estrutura Molecular , Compostos Organometálicos/química , Processos Fotoquímicos , Estereoisomerismo
8.
Nat Methods ; 17(5): 515-523, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32251394

RESUMO

Transcription is a highly dynamic process that generates single-stranded DNA (ssDNA) in the genome as 'transcription bubbles'. Here we describe a kethoxal-assisted single-stranded DNA sequencing (KAS-seq) approach, based on the fast and specific reaction between N3-kethoxal and guanines in ssDNA. KAS-seq allows rapid (within 5 min), sensitive and genome-wide capture and mapping of ssDNA produced by transcriptionally active RNA polymerases or other processes in situ using as few as 1,000 cells. KAS-seq enables definition of a group of enhancers that are single-stranded and enrich unique sequence motifs. These enhancers are associated with specific transcription-factor binding and exhibit more enhancer-promoter interactions than typical enhancers do. Under conditions that inhibit protein condensation, KAS-seq uncovers a rapid release of RNA polymerase II (Pol II) from a group of promoters. KAS-seq thus facilitates fast and accurate analysis of transcription dynamics and enhancer activities simultaneously in both low-input and high-throughput manner.


Assuntos
Aldeídos/química , DNA de Cadeia Simples/análise , DNA de Cadeia Simples/química , Elementos Facilitadores Genéticos , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Regiões Promotoras Genéticas , Análise de Sequência de DNA/métodos , Animais , DNA de Cadeia Simples/genética , Regulação da Expressão Gênica , Humanos , Camundongos , Transcrição Genética
9.
J Food Sci ; 85(5): 1548-1564, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32249935

RESUMO

Mandarins (or tangerines) are mainly consumed as fresh fruits due to the ease of peeling and desirable flavor. Sweetness, acidity, and flavor of mandarin are the most important criteria for consumer preference. The objective of this study was to evaluate the effects of harvest date on sensory and chemical components of four mandarin cultivars (Murcott, 411, Temple, and 'LB8-9' Sugar Belle®). Volatiles were extracted from the headspace of juice samples with solid phase microextraction (SPME) and analyzed using gas chromatography-mass spectrometry (GC-MS). The optimum harvest window for eating quality of 411 was late January to mid-February (soluble solids content [SSC]/titratable acidity [TA]: 11.3 to 14.0), Sugar Belle® fruits were best tasted when harvested from mid- to end of January (SSC/TA: 14.1 to 16.1), and February was the best month for harvesting Murcott (SSC/TA: 13.10 to 18.0) and Temple (SSC/TA:10.3 to 12.50). Sensory perception of sweetness, ripeness, and juiciness increased as SSC/TA increased while sourness and bitterness decreased. Pumpkin flavor, an indicator of overripe fruit, was mainly noticed late in the season. Tangerine flavor tended to decrease, whereas fruity-noncitrus flavor tended to increase with fruit maturity. Monoterpenes were the most abundant volatiles and tended to decrease with fruit maturity, whereas alcohols, esters, and aldehydes increase. Aldehydes, esters, and alcohols were positively correlated with sweetness, ripeness, juiciness, and fruity characteristics, and negatively with sourness and bitterness. On the other hand, monoterpenes were positively correlated with bitterness and tangerine flavor, and negatively correlated with sweetness and fruity-noncitrus flavor. The highest number of esters was found in Temple, whereas Murcott and 411 were high in aldehydes.


Assuntos
Citrus/genética , Aromatizantes/química , Frutas/crescimento & desenvolvimento , Aldeídos/química , Aldeídos/isolamento & purificação , Cruzamento , Citrus/química , Citrus/classificação , Citrus/crescimento & desenvolvimento , Comportamento do Consumidor , Ésteres/química , Ésteres/isolamento & purificação , Aromatizantes/isolamento & purificação , Frutas/química , Frutas/classificação , Frutas/genética , Cromatografia Gasosa-Espectrometria de Massas , Humanos , Monoterpenos/química , Monoterpenos/isolamento & purificação , Microextração em Fase Sólida , Paladar , Compostos Orgânicos Voláteis/análise , Compostos Orgânicos Voláteis/isolamento & purificação
10.
Mar Biotechnol (NY) ; 22(2): 317-330, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32124098

RESUMO

The organic synthesis has been driven by the need of sustainable processes, which also requires efficiency and cost-effectiveness. In this work, we described the synthesis of nine Knoevenagel adducts between cyanoacetamide and aromatic aldehydes ((E)-2-cyano-3-(phenyl)acrylamide derivatives), employing triethylamine as catalyst under microwave irradiation in 30 min with excellent yields (93-99% yield). Then, these adducts were employed in the C-C double bond bioreduction by the marine-derived fungus Cladosporium sp. CBMAI 1237 for obtention of 2-cyano-3-phenylpropanamide derivatives in mild conditions and short reaction time for a whole-cells reduction (phosphate buffer pH 7.0, 32 °C, 130 rpm, 8 h) with good yields (48-90%). It is important to emphasize that the experimental conditions, especially the reaction time, should be carefully evaluated for the obtention of high yields. Since a biodegradation process consumed the obtained product in extended periods, probably due to the use of the substrate as carbon and nitrogen source. This approach showed that the use of coupled and greener catalysis methods such as microwave irradiation and biocatalytic reduction, which employs unique biocatalysts like marine-derived fungi, can be an interesting tool for the obtention of organic molecules.


Assuntos
Amidas/síntese química , Biocatálise , Cladosporium/metabolismo , Micro-Ondas , Aldeídos/química , Etilaminas/química , Nitrilos/química
11.
Nat Commun ; 11(1): 784, 2020 02 07.
Artigo em Inglês | MEDLINE | ID: mdl-32034159

RESUMO

Relatively robust dynamic covalent interactions have been employed extensively to mediate molecular self-assembly reactions; however, these assembly processes often do not converge to a thermodynamic equilibrium, instead yielding mixtures of kinetically-trapped species. Here, we report a dynamic covalent self-assembly process that mitigates kinetic trapping such that multiple unique oligomers bearing covalently coreactive pendant groups are able to undergo simultaneous, sequence-selective hybridization with their complementary strands to afford biomimetic, in-registry molecular ladders with covalent rungs. Analogous to the thermal cycling commonly employed for nucleic acid melting and annealing, this is achieved by raising and lowering the concentration of a multi-role reagent to effect quantitative dissociation and subsequently catalyze covalent bond rearrangement, affording selective assembly of the oligomeric sequences. The hybridization specificity afforded by this process further enabled information encoded in oligomers to be retrieved through selective hybridization with complementary, mass-labeled sequences.


Assuntos
Bioquímica/métodos , Peptoides/química , Aldeídos/química , Aminas/química , Fluoresceínas/química , Transferência Ressonante de Energia de Fluorescência , Iminas/química , Cinética , Hibridização de Ácido Nucleico , Peptoides/síntese química , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , p-Dimetilaminoazobenzeno/análogos & derivados , p-Dimetilaminoazobenzeno/química
12.
Biomed Chromatogr ; 34(4): e4807, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32020626

RESUMO

Periplocae Cortex, named Xiang-Jia-Pi in China, has been widely used to treat autoimmune diseases, especially rheumatoid arthritis. However, the in vivo substances of Periplocae Cortex remain unknown yet. In this study, an ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry was used for profiling the chemical components and related metabolites of Periplocae Cortex. A total of 98 constituents were identified or tentatively characterized in Periplocae Cortex: 42 C21 steroidal glycosides, 10 cardiac glycosides, 23 organic acids, 4 aldehydes, 7 triterpenes, and 12 other types. Among them, 18 components were unambiguously identified by comparison with reference standards. In addition, 176 related xenobiotics (34 prototypes and 142 metabolites) were screened out and characterized in rats' biosamples (plasma, urine, bile, and feces) after the oral administration of Periplocae Cortex. Moreover, the metabolic fate of periplocoside S-4a, a C21 steroidal glycoside, was proposed for the first time. In summary, phase II reactions (methylation, glucuronidation, and sulfation), phase I reactions (hydrolysis reactions, oxygenation, and reduction), and their combinations were the predominant metabolic reactions of Periplocae Cortex in rat. It is the first report to reveal the in vivo substances and metabolism feature of Periplocae Cortex. This study also provided meaningful information for further pharmacodynamics study of Periplocae Cortex, as well as its quality control research.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Medicamentos de Ervas Chinesas/análise , Medicamentos de Ervas Chinesas/metabolismo , Espectrometria de Massas/métodos , Periploca/química , Administração Oral , Aldeídos/análise , Aldeídos/química , Animais , Medicamentos de Ervas Chinesas/administração & dosagem , Medicamentos de Ervas Chinesas/química , Glicosídeos/análise , Glicosídeos/química , Masculino , Casca de Planta/química , Raízes de Plantas/química , Ratos , Ratos Sprague-Dawley , Triterpenos/análise , Triterpenos/química
13.
Chem Commun (Camb) ; 56(18): 2775-2778, 2020 Mar 03.
Artigo em Inglês | MEDLINE | ID: mdl-32022095

RESUMO

The expeditious construction of phenanthridine scaffolds via a Pd/MnO2-mediated C-H arylation/oxidative annulation cascade involving aldehydes, aryl iodides and amino acids is disclosed. This reaction proceeds smoothly involving the formation of multiple chemical bonds with the tolerance of a wide range of functional groups. The control experiments suggest a radical mechanism for C-N bond formation via MnO2-promoted oxidative annulation of imine compounds. The synthetic utility of this transformation has been demonstrated via the straightforward access to bioactive natural alkaloid trisphaeridine and its analogue.


Assuntos
Aldeídos/química , Aminoácidos/química , Hidrocarbonetos Iodados/química , Ácido Oxálico/química , Paládio/química , Fenantridinas/síntese química , Estrutura Molecular , Oxirredução , Fenantridinas/química
14.
J Toxicol Environ Health A ; 83(1): 1-8, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32019422

RESUMO

Olfactory receptor (OR) genes are extensively distributed throughout the human organism. Although these receptors are predominantly located in the olfactory epithelium, binding between odorant chemicals and corresponding ORs initiates downstream events in other tissues. In particular, exposure to allergen fragrances results in the induction of contact dermatitis. At present, current methodologies are limited in their ability to predict the consequences of fragrancy chemicals on humans. The aim of this study was designed to simulate the bindingstructure between lyral and OR10J5, a known allergen which produces contact dermatitis, and its corresponding OR OR10J5 in an effort to predict dermal outcomes using computational methods. Results demonstrated that binding between lyral and OR10J5 involved amino acid residues Phe104, Val105, Cyx178, Ile180, and Tyr258, respectively, which were located on binding sites of the receptor transmembrane 3(TM3), TM3, extracellular loop 2(EL2), EL2, TM6. Evidence indicates that computer simulating binding interactions occurred between an odorant chemical and its receptors which initiated downstream alterations accounting possibly for the observed in vivo contact dermatitis.


Assuntos
Aldeídos/química , Cicloexenos/química , Modelos Químicos , Receptores Odorantes/química , Sequência de Aminoácidos , Simulação por Computador , Humanos , Modelos Moleculares , Ligação Proteica , Conformação Proteica , Receptores Adrenérgicos beta 2/química
15.
Macromol Rapid Commun ; 41(6): e1900586, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32022359

RESUMO

Orthogonal dynamic covalent self-assembly is used as a facile method for constructing polymer hollow nanocapsules (NCs) and thin films. The bifunctional precursor 4-formylphenylboronic acid is symmetrically installed with a boronic acid group for the boroxine linkage, and an aldehyde group for the Schiff base reaction which can react with twofold symmetry linkers ethylenediamine and para phenylenediamine to attain polymer NCs and nanosheets. Owing to the reversibility of the imine linkages, the mutual morphological transformation between polymer NCs and thin films via an amine-imine-exchange strategy is successfully achieved. Multiple reversible covalent bonds allow the control the release of the load in polymer NCs using different techniques. This may be useful for designing stimulus-responsive smart materials.


Assuntos
Benzaldeídos/química , Ácidos Borônicos/química , Etilenodiaminas/química , Iminas/química , Nanocápsulas/química , Fenilenodiaminas/química , Polímeros/química , Polímeros/síntese química , Aldeídos/química , Aminas/química , Nanocápsulas/ultraestrutura , Nanoestruturas/química , Nanoestruturas/ultraestrutura , Bases de Schiff/química , Propriedades de Superfície
16.
Nat Chem Biol ; 16(5): 489-492, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32015521

RESUMO

RNA secondary structure is critical to RNA regulation and function. We report a new N3-kethoxal reagent that allows fast and reversible labeling of single-stranded guanine bases in live cells. This N3-kethoxal-based chemistry allows efficient RNA labeling under mild conditions and transcriptome-wide RNA secondary structure mapping.


Assuntos
Aldeídos/química , RNA/química , Animais , Células-Tronco Embrionárias , Guanina/química , Células HeLa , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Camundongos , Conformação de Ácido Nucleico , Ácidos Nucleicos Heteroduplexes , Dobramento de RNA , Transcriptoma
17.
Proc Natl Acad Sci U S A ; 117(3): 1419-1428, 2020 01 21.
Artigo em Inglês | MEDLINE | ID: mdl-31896585

RESUMO

By constructing an in vivo-assembled, catalytically proficient peroxidase, C45, we have recently demonstrated the catalytic potential of simple, de novo-designed heme proteins. Here, we show that C45's enzymatic activity extends to the efficient and stereoselective intermolecular transfer of carbenes to olefins, heterocycles, aldehydes, and amines. Not only is this a report of carbene transferase activity in a completely de novo protein, but also of enzyme-catalyzed ring expansion of aromatic heterocycles via carbene transfer by any enzyme.


Assuntos
Biocatálise , Proteínas de Escherichia coli/química , Metano/análogos & derivados , Peroxidases/química , Aldeídos/química , Alcenos/química , Aminas/química , Escherichia coli , Proteínas de Escherichia coli/metabolismo , Metano/química , Peroxidases/metabolismo , Especificidade por Substrato
18.
J Chem Ecol ; 46(2): 128-137, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31907752

RESUMO

Cuticular compounds (CCs) that cover the surface of insects primarily serve as protection against entomopathogens, harmful substances, and desiccation. However, CCs may also have secondary signaling functions. By studying the role of CCs in intraspecific interactions, we may advance our understanding of the evolution of pheromonal communication in insects. We previously found that the gregarious parasitoid, Cotesia glomerata (L.), uses heptanal as a repellent pheromone to help avoid mate competition among sibling males, whereas another cuticular aldehyde, nonanal, is part of the female-produced attractive sex pheromone. Here, we show that the same aldehydes have different pheromonal functions in a related solitary parasitoid, Cotesia marginiventris (Cresson). Heptanal enhances the attractiveness of the female's sex pheromone, whereas nonanal does not affect a female's attractiveness. Hence, these common aldehydes are differentially used by the two Cotesia species to mediate, synergistically, the attractiveness of the main constituents of their respective sex pheromones. The specificity of the complete sex pheromone blend is apparently regulated by two specific, less volatile compounds, which evoke strong electroantennographic (EAG) responses. This is the first demonstration that volatile CCs have evolved distinct pheromonal functions to aid divergent mating strategies in closely related species. We discuss the possibility that additional compounds are involved in attraction and that, like the aldehydes, they are likely oxidative products of unsaturated cuticular hydrocarbons.


Assuntos
Aldeídos/química , Himenópteros/fisiologia , Atrativos Sexuais/química , Aldeídos/análise , Aldeídos/farmacologia , Animais , Sinais (Psicologia) , Feminino , Cromatografia Gasosa-Espectrometria de Massas , Masculino , Atrativos Sexuais/análise , Atrativos Sexuais/farmacologia , Comportamento Sexual Animal/efeitos dos fármacos , Compostos Orgânicos Voláteis/análise , Compostos Orgânicos Voláteis/química , Compostos Orgânicos Voláteis/isolamento & purificação
19.
Chem Commun (Camb) ; 56(13): 2020-2022, 2020 Feb 13.
Artigo em Inglês | MEDLINE | ID: mdl-31961350

RESUMO

Homo-dimerizations of a variety of aldosulose and aldonolactone derivatives via aldol and Claisen reactions have been achieved, leading to novel branched higher carbon sugars in a highly stereoselective manner.


Assuntos
Lactonas/química , Açúcares/química , Aldeídos/química , Dimerização , Estereoisomerismo
20.
Food Chem ; 314: 126183, 2020 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-31972407

RESUMO

Phenolic compounds largely contribute to the nutraceutical properties of virgin olive oil (VOO), the organoleptic attributes and the shelf life due to their antioxidant capabilities. Due to the relevance of malaxation in the oil extraction process, we tested the effects of malaxation time on the concentrations of relevant phenolic compounds in VOO, and we evaluated the influence of performing malaxation under vacuum. An increase in malaxation time significantly decreased the concentrations of aglycone isomers of oleuropein and ligstroside but, conversely, increased the oleocanthal and oleacein contents. Additionally, malaxation under vacuum led to an increase in phenolic contents compared to standard conditions carried out at atmospheric pressure. Finally, we explored the possibility of predicting the VOO oxidative stability on the basis of the phenolic profile, and a model (R2 = 0.923; p < 0.0001) was obtained by combining the concentration of the VOO phenolic compounds and the main fatty acids.


Assuntos
Manipulação de Alimentos/métodos , Azeite de Oliva/química , Fenóis/análise , Fenóis/química , Aldeídos/análise , Aldeídos/química , Monoterpenos Ciclopentânicos/análise , Monoterpenos Ciclopentânicos/química , Ácidos Graxos/análise , Ácidos Graxos/química , Glucosídeos/análise , Glucosídeos/química , Iridoides/análise , Iridoides/química , Azeite de Oliva/análise , Oxirredução , Piranos/análise , Piranos/química , Temperatura , Fatores de Tempo
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