Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 4.324
Filtrar
1.
Chem Commun (Camb) ; 55(100): 15105-15108, 2019 Dec 28.
Artigo em Inglês | MEDLINE | ID: mdl-31782427

RESUMO

Herein, we report the nor-AZADO-catalyzed exhaustive aerobic oxidations of 1,2-diols to α-keto acids. Combining oxidation with transamination using dl-2-phenylglycine led to the synthesis of free α-amino acids (AAs) in one pot. This method enables the rapid and flexible preparation of a variety of valuable unnatural AAs, such as fluorescent AAs, photoactivatable AAs, and other functional AAs for bioorthogonal reactions.


Assuntos
Álcoois/química , Aminoácidos/química , Adamantano/análogos & derivados , Adamantano/química , Catálise , Óxidos N-Cíclicos/química , Cetoácidos/química , Oxirredução
2.
Ecotoxicol Environ Saf ; 186: 109759, 2019 Dec 30.
Artigo em Inglês | MEDLINE | ID: mdl-31606646

RESUMO

Rhizobia have a significant agronomic and environmental role and are eminent contributors to soil fertility. However, this group of microorganisms are affected by various environmental stresses, such as Cd contamination. High Cd concentrations change bacterial metabolism. During this metabolic shift, bacteria alter their volatilome (the set of volatile metabolites synthesized by an organism). In the presence of Cd, peak areas of saturated aldehydes and alcohols were previously reported to increase, and the consequences of this increase to cells are poorly known. In this study, Rhizobium sp. strain E20-8 cells were exposed to Cd and aldehydes or their conjugated alcohols. Exposure to Cd (100 µM) inhibited cell growth and induced several biomarkers of oxidative stress. The present study also evidenced the higher toxicity of most aldehydes relatively to the corresponding alcohol in the presence of Cd, suggesting that reduction of aldehydes into alcohols may be an effective mechanism to restrain aldehydes toxicity in Rhizobium cells under Cd toxicity. Nonetheless, the protective effect was dependent on the pair aldehyde-respective alcohol considered and it differed between Cd stressed and non-stressed cells. Differences in the ability to convert aldehydes to alcohols may emerge as a new feature helping explain the oxidative tolerance variability among bacteria.


Assuntos
Álcoois/química , Aldeídos/química , Cádmio/toxicidade , Rhizobium/efeitos dos fármacos , Poluentes do Solo/toxicidade , Antioxidantes/metabolismo , Tolerância a Medicamentos , Peroxidação de Lipídeos/efeitos dos fármacos , Oxirredução , Rhizobium/crescimento & desenvolvimento , Rhizobium/metabolismo , Solo/química
3.
J Food Sci ; 84(10): 2758-2776, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31509249

RESUMO

The changes of volatile compounds in soy sauce during long-term fermentation (12 months) were investigated using solid-phase microextraction (SPME) and stir bar sorptive extraction (SBSE). A total of 144 and 129 compounds were identified in soy sauce with long-term fermentation by SPME and SBSE, respectively. The contents of most compounds, such as acids, aldehydes, benzene and benzene derivatives, esters, lactones, pyrazines, pyrones, and pyrroles, showed a tendency to increase, whereas those of alcohols and ketones decreased according to long-term fermentation. In addition, principal component analysis and partial least squares discriminant analysis were applied to discriminate soy sauce samples according to fermentation periods and determine key volatile compounds related to long-term fermentation. The initial fermentation stages were mainly associated with some alcohols, ketones, and lactones, whereas the later stages were strongly associated with most esters, some phenols, benzene and benzene derivatives, and pyrroles. Moreover, the key volatile compounds associated with long-term fermentation in soy sauce samples were ethyl 3-methylbutanoate (ethyl isovalerate), ethyl pentanoate (ethyl valerate), 1-octen-3-yl acetate, 3-(methylthio)-1-propanol (methionol), ethyl benzoate, ethyl 2-phenylacetate, 1-(1H-pyrrol-2-yl)ethanone (2-acetylpyrrole), and 5-pentyl-2-oxolanone (γ-nonalactone). PRACTICAL APPLICATION: This study investigated changes of volatile compounds in soy sauce during long-term fermentation (12 months) using solid-phase microextraction and stir bar sorptive extraction. In addition, the key volatile compounds associated with long-term fermentation in soy sauce samples were determined. These results may help to predict the effective contributors related to long-term fermentation of soy sauce and improve the quality of soy sauce during long-term fermentation.


Assuntos
Alimentos de Soja/análise , Compostos Orgânicos Voláteis/química , Álcoois/química , Álcoois/isolamento & purificação , Aldeídos/química , Aldeídos/isolamento & purificação , Fermentação , Cetonas/química , Cetonas/isolamento & purificação , Lactonas/química , Lactonas/isolamento & purificação , Microextração em Fase Sólida , Soja/química , Compostos Orgânicos Voláteis/isolamento & purificação
4.
Nat Commun ; 10(1): 3590, 2019 08 09.
Artigo em Inglês | MEDLINE | ID: mdl-31399569

RESUMO

Organocatalysis is an important branch of catalysis for various organic transformations and materials preparation. Polymerizations promoted by organic catalysts can produce polymeric materials without any metallic residues, providing charming materials for high-value and sensitive domains such as biomedical applications, microelectronic devices and food packaging. Herein, we describe a fluorinated alcohol based catalytic system for polypeptide synthesis via catalytic ring-opening polymerization (ROP) of α-amino acid N-carboxyanhydride (NCA), fulfilling cocatalyst free, metal free, high rate and high selectivity. During polymerization, the fluorinated alcohol catalyst forms multiple dynamic hydrogen bonds with the initiator, monomer and propagating polymer chain. These cooperative hydrogen bonding interactions activate the NCA monomers and simultaneously protect the overactive initiator/propagating polymer chain-ends, which offers the whole polymerization with high activity and selectivity. Mechanistic studies indicate a monocomponent-multifunctional catalytic mode of fluorinated alcohol. This finding provides a metal free and fast approach to access well-defined polypeptides.


Assuntos
Álcoois/química , Técnicas de Química Sintética/métodos , Peptídeos/síntese química , Polimerização , Aminoácidos/química , Catálise , Halogenação
5.
Chemosphere ; 237: 124454, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31369905

RESUMO

This study investigated the degradation of norfloxacin by persulfate activated with corn stalk biochar. The results demonstrate that corn stalk biochar is a green and low-cost carbon material with excellent catalytic activity for the metal-free activation of persulfate to degrade norfloxacin. The removal rate of norfloxacin increased with the increase in the dosage of persulfate, but the increased ratio gradually decreased. With alcohols and phenols as free radical trapping agents, it was determined that norfloxacin degradation by SO- 4· and HO· in the biochar/persulfate system occurred mainly on the surface or boundary layer of biochar. pH has an important effect on norfloxacin degradation in the biochar/persulfate system. Norfloxacin degradation performances under different initial pH conditions are decreased according to the following order: (initial pH 6.5) > (initial pH 3.4) > (initial pH 10.6). The effects of pH on norfloxacin degradation in the biochar/persulfate system was mainly realized through affecting norfloxacin adsorption on corn stalk biochar surface.


Assuntos
Antibacterianos/química , Carvão Vegetal/química , Norfloxacino/química , Sulfatos/química , Adsorção , Álcoois/química , Recuperação e Remediação Ambiental , Radicais Livres/química , Concentração de Íons de Hidrogênio , Fenóis/química , Zea mays
6.
Molecules ; 24(17)2019 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-31438523

RESUMO

In the present study we aimed to investigate the volatile organic compounds (VOCs) that may potentially be responsible for specific descriptors of Madeira wine providing details about Madeira wine aroma notes at molecular level. Moreover, the wine aroma profile, based on the obtained data, will be a starting point to evaluate the impact of grape variety (Malvasia, Bual, Sercial, Verdelho and Tinta Negra), type (sweet, medium sweet, dry and medium dry), and age (from 3 to 20 years old) on Madeira wine sensorial properties. Firstly, a comprehensive and in-depth Madeira wine volatile profiling was carried out using headspace solid-phase microextraction combined with gas chromatography-mass spectrometry (HS-SPME/GC-qMS). Secondly, a relation among the varietal, fermentative and aging aroma compounds, and their aroma descriptors with the Madeira wine sensorial properties was assessed. A total of 82 VOCs, belonging to different chemical families were identified, namely 21 esters, 13 higher alcohols, ten terpenic compounds, nine fatty acids, seven furanic compounds, seven norisoprenoids, six lactones, four acetals, four volatile phenols and one sulphur compound. From a sensorial point of view, during the aging process the wine lost its freshness and fruitiness odor related to the presence of some varietal and fermentative compounds, whereas other descriptors such as caramel, dried fruits, spicy, toasty and woody, arose during ageing. The Maillard reaction and diffusion from the oak were the most important pathways related with these descriptors. A relationship-based approach was used to explore the impact of grape variety, wine type, and age on Madeira wine sensorial properties based on shared number of VOCs and their odors.


Assuntos
Odorantes/análise , Vinho , Acetais/química , Álcoois/química , Ácidos Graxos/química , Cromatografia Gasosa-Espectrometria de Massas , Lactonas/química , Microextração em Fase Sólida , Terpenos/química , Vitis/química , Compostos Orgânicos Voláteis/análise
7.
Molecules ; 24(14)2019 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-31319482

RESUMO

Distribution of volatile compounds in different fruit structures were analyzed in four tomato cultivars by headspace-solid-phase microextraction (SPME)-gas chromatography-mass spectrometry (GC-MS). A total of 36 volatile compounds were identified in fruit samples, which were primarily aldehydes, hydrocarbons, alcohols, ketones, furans, esters, nitrogen compounds, and sulfur and nitrogen-containing heterocyclic compounds. The volatile compositions in pericarp (PE), septa and columella (SC), locular gel and seeds (LS), and stem end (SE) tissues showed different profiles. The PE tissue showed the highest total volatile concentration due to a high abundance of aldehydes, especially cis-3-hexenal and benzaldehyde. Meanwhile, it showed higher aromatic proportion and herbaceous series intensity than other tissues. Floral and fruity series showed higher intensity in SC and LS tissues. The concentration of alcohols in the LS was higher than that in other tissues in association with the higher abundances of 2-methyl propanol, 3-methyl butanol, and 2-methyl butanol. However, the numbers and concentrations of volatile compounds, especially cis-3-hexenal, benzaldehyde, and geranyl acetone were lower in SE than in the other tissues, indicating less tomato aromas in SE. SE tissues were also lacking in floral and fruity characteristic compounds, such as geranyl acetone, 1-nitro-pentane, and 1-nitro-2-phenylethane. "FL 47" contained more volatile compounds than the other three, and the contents of aldehydes, ketones and oxygen-containing heterocyclic compounds in the "Tygress" fruit were higher than the other cultivars.


Assuntos
Frutas/química , Lycopersicon esculentum/química , Compostos Orgânicos Voláteis/classificação , Compostos Orgânicos Voláteis/isolamento & purificação , Álcoois/química , Aldeídos/química , Ésteres/química , Cromatografia Gasosa-Espectrometria de Massas , Cetonas/química , Odorantes/análise , Sementes/química , Microextração em Fase Sólida , Compostos Orgânicos Voláteis/química
8.
Chemistry ; 25(51): 11945-11954, 2019 Sep 12.
Artigo em Inglês | MEDLINE | ID: mdl-31294500

RESUMO

Acyl transferase from Mycobacterium smegmatis (MsAcT) is a promising biocatalyst because it catalyzes an acyl transfer reaction in aqueous solution, thereby accepting many primary and secondary alcohols as substrates. MsAcT also exhibits high enantioselectivity for a selected number of secondary alcohols. To increase the applicability of this enzyme for the production of optically active compounds, a detailed understanding of the reaction mechanism and the factors that affect enantioselectivity is essential. Herein, quantum chemical calculations are employed to study the reactions of two secondary alcohols, 1-isopropyl propargyl alcohol and 2-hydroxy propanenitrile, for which the enzyme displays opposite enantiopreference, favoring the S enantiomer in the former case and R enantiomer in the latter. A model of the active site has been designed and for both substrates various binding modes are evaluated and the intermediates and transition states along the reaction path are then located. The calculated energy profiles agree with the experimental observations, and reproduce the selectivity outcome. Through a detailed analysis of the geometries of key transition states, insights into the origins of the enantiopreference are obtained.


Assuntos
Álcoois/química , Mycobacterium smegmatis/química , Transferases/metabolismo , Catálise , Domínio Catalítico , Estereoisomerismo
9.
Food Chem ; 298: 125064, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31260954

RESUMO

Edible films based on gelatin and chitosan have high gas and aroma barrier properties. This study focused on their capability to sorbed/retain aroma compounds (1-hexanal, 2-hexen-1-ol, 1-hexanol, 3-hexanone and phenol) at three relative humidity level (≤2%, 53% or 84% RH). Whatever the relative humidity condition, the order of sorption is keton (3-hexanone) < aldehyde (1-hexanal) < aliphatic alcohols (2-hexen-1-ol and 1-hexanol) < phenol. This order could be related to the intrinsic chemical properties of aroma compounds. The increase in moisture enhanced the sorption at the highest RH for all the aroma compounds. However, a competition between water and aliphatic alcohols is observed at 53%RH. All compounds have an ideal sorption behaviour (logarithmic increase) except 1-hexanal. The sorption of 1-hexanal, 1-hexanol, 2-hexen-1-ol and 3-hexanone induced an antiplasticization of the network by increasing the film Tg by more than 5 °C. On the contrary, phenol was an efficient plasticizer at least as high as moisture.


Assuntos
Quitosana/química , Gelatina/química , Compostos Orgânicos Voláteis/química , Adsorção , Álcoois/química , Varredura Diferencial de Calorimetria , Cromatografia Gasosa , Umidade , Cetonas/química , Cinética , Fenol/química , Temperatura Ambiente
10.
Molecules ; 24(11)2019 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-31159367

RESUMO

Acyclic monoterpenes constitute a large and highly abundant class of secondary plant metabolites and are, therefore, attractive low-cost raw materials for the chemical industry. To date, numerous biocatalysts for their transformation are known, giving access to highly sought-after monoterpenoids. In view of the high selectivity associated with many of these reactions, the demand for enzymes generating commercially important target molecules is unabated. Here, linalool (de)hydratase-isomerase (Ldi, EC 4.2.1.127) from Castellaniella defragrans was examined for the regio- and stereoselective hydration of the acyclic monoterpene ß-myrcene to (S)-(+)-linalool. Expression of the native enzyme in Escherichia coli allowed for identification of bottlenecks limiting enzyme activity, which were investigated by mutating selected residues implied in enzyme assembly and function. Combining these analyses with the recently published 3D structures of Ldi highlighted the precisely coordinated reduction-oxidation state of two cysteine pairs in correct oligomeric assembly and the catalytic mechanism, respectively. Subcellular targeting studies upon fusion of Ldi to different signal sequences revealed the significance of periplasmic localization of the mature enzyme in the heterologous expression host. This study provides biochemical and mechanistic insight into the hydration of ß-myrcene, a nonfunctionalized terpene, and emphasizes its potential for access to scarcely available but commercially interesting tertiary alcohols.


Assuntos
Alcenos/metabolismo , Betaproteobacteria/metabolismo , Hidroliases/metabolismo , Monoterpenos/metabolismo , Álcoois/química , Álcoois/metabolismo , Alcenos/química , Catálise , Escherichia coli/metabolismo , Hidroliases/química , Hidrólise , Isomerases , Monoterpenos/química
11.
J Food Sci ; 84(7): 1949-1956, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31245855

RESUMO

Maotai liquor is one of the most famous traditional Chinese distilled liquor enjoyed by many people all over the world for its unique production method, impressive liquor quality, and soy sauce-like and roasted aroma style. It is known that aroma characteristics of liquor mainly depend on the aroma compounds. Alcohols as one of the most important categories of aroma components have been determined in Maotai liquor. However, the systemic analysis of alcoholic compounds in liquor is limited, especially the active alcoholic components and their pharmacological effects. Therefore, in this study, a systemic analysis method was proposed by combining in silico absorption, distribution, metabolism, and excretion (ADME) evaluation, target fishing, network pharmacology technology, pathway analysis, and experimental verification to interpret the pharmacological mechanism of alcoholic compounds in Maotai liquor. Finally, 15 compounds with favorable pharmacokinetic profiles were screened through in silico ADME models. Thirty-eight related targets of these active compounds were identified by target prediction method. The network pharmacology and pathway analysis were developed to clarify the pharmacological effect of alcoholic compounds in Maotai liquor at the system and pathway level. Moreover, the key active compounds were validated by in vitro experiments that verified the effectiveness of our methods. Our study provides a novel approach to systematically analyze the pharmacological effect of alcoholic compounds in Maotai liquor, which would be beneficial for promoting the in-depth study of various liquors. PRACTICAL APPLICATION: Maotai liquor is popularly enjoyed in the world for a very long time. However, the systemic analysis of compounds in liquor is limited. Our systematic analysis approach was developed to explore the bioactive ingredients and their related target proteins as well as the pharmacological effects of Maotai liquor. This will provide a new method to understand the pharmacological mechanisms of compounds in various liquors at the systems level, so as to promote the development of liquors and to increase the public awareness of science about alcohol consumption.


Assuntos
Álcoois/química , Aromatizantes/química , Vinho/análise , Álcoois/farmacologia , Animais , China , Aromatizantes/farmacologia , Expressão Gênica/efeitos dos fármacos , Camundongos , Odorantes/análise , Células RAW 264.7
12.
Plant Foods Hum Nutr ; 74(3): 358-363, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31209703

RESUMO

The aim of the present study was to identify volatile organic compounds (VOCs) by SPME-GC and quantify the bioactive compounds (ascorbic acid, total flavonoids and total phenolic content), antioxidant capacity (DPPH and ORAC) and physicochemical characteristics of ocorocillo, cambucá, murici da praia and murici do campo, four native South American fruits. A total of 41 volatile compounds were identified in ocorocillo, of which 17 were terpenes. Cambuca's volatile profile contained aldehydes, aromatic hydrocarbons and alcohols. Murici da praia and murici do campo contained high levels of fatty acid volatiles and esters, that contribute to their remarkable aroma. Ocorocillo contained high levels of ascorbic acid and total flavonoids, while cambucá presented lower ascorbic acid, flavonoid and phenolic levels. Murici da praia and murici do campo contained high amounts of phenolic compounds and high free-radical scavenging capacity (DPPH and ORAC). In addition, this fruit was sweeter and less acid compared to the other assessed fruits. The results suggest that these native fruits constitute a good source of volatile compounds and bioactive compounds, which may aid in their preservation interest and potential use in the food, cosmetic and pharmaceutical industries.


Assuntos
Antioxidantes/análise , Eugenia/química , Frutas/química , Malpighiaceae/química , Myrtaceae/química , Compostos Orgânicos Voláteis/análise , Álcoois/química , Fenômenos Químicos , Cromatografia Gasosa , Flavonoides/análise , Depuradores de Radicais Livres/análise , Fenóis/análise , Compostos Fitoquímicos/análise , Microextração em Fase Sólida , Terpenos/análise
13.
J Pharm Biomed Anal ; 172: 200-205, 2019 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-31060032

RESUMO

Policosanols (PCs) are a mixture of long chain primary aliphatic alcohols mainly known for their ability to reduce cholesterol level. Due to this property, there is an increasing interest in the extraction process of these compounds. In this context, beeswax, a natural product produced by honey bees of the genus Apis, is a promising source for their extraction and purification. The present research work was aimed at the development of a new procedure for the extraction and purification of PCs from yellow beeswax by using microwave-assisted technology, which hitherto has never been applied to this mixture. The developed process comprises three main steps: 1) microwave-assisted trans-esterification; 2) microwave-assisted hydrolysis; 3) final purification by means of preparative liquid chromatography. The final step is responsible for the increased purity of PCs, thanks to the removal of undesired compounds, such as natural paraffins. The predominant alcohols investigated in this work are tetracosanol (C24OH), hexacosanol (C26OH), octacosanol (C28OH), triacontanol (C30OH) and dotriacontanol (C32OH). Compound identification was performed using GC-EI-MS, while GC-FID analysis was chosen for the quantification of the main fatty alcohols present in the product. This new method represents a useful tool for the production of PCs from beeswax to be used in pharmaceuticals and nutraceuticals for human use, feed and veterinary supplements.


Assuntos
Álcoois Graxos/química , Tecnologia Farmacêutica/instrumentação , Tecnologia Farmacêutica/métodos , Ceras/química , Álcoois/química , Animais , Abelhas , Produtos Biológicos/química , Cromatografia Gasosa-Espectrometria de Massas/métodos , Micro-Ondas
14.
J Chromatogr A ; 1597: 196-201, 2019 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-31054834

RESUMO

Hexafluoroisopropanol (HFIP) was used as a phase-separation solvent to develop novel alcohol-salt aqueous two-phase systems (ATPSs) with various salts. Phase diagram and effective excluded volume (EEV) study proved that HFIP has much better phase-separation ability compared to traditional small molecule alcohols (ethanol, isopropanol and n-propanol). Then, the HFIP-NaCl ATPS was applied for the extraction and purification of chlorogenic acid (CGA) from ramie leaves. Under the optimum conditions (2 M NaCl solution with pH 3.0, the volume ratio of NaCl solution to HFIP at 6, vortex time 5 s and centrifugation time 7 min), the extraction efficiency of CGA in the salt-rich phase was 99.3%, meanwhile the HFIP-rich phase could extract a large amount of impurities. Furthermore, the CGA product with the purity of 91.0% was obtained from the salt-rich phase by semi-preparative liquid chromatography and salt removal, and its chemical structure was identified. Compared with other ATPSs, the HFIP-NaCl ATPS consumed much less organic solvent and salt, but acquired much higher extraction efficiency and obvious impurity-removal effect. Therefore, the HFIP-based alcohol-salt ATPSs are promising in the extraction and purification of CGA and other polar compounds as well.


Assuntos
Boehmeria/química , Ácido Clorogênico/isolamento & purificação , Cromatografia Líquida , Extratos Vegetais/isolamento & purificação , Folhas de Planta/química , Propanóis/química , Cloreto de Sódio/química , Álcoois/química , Solventes/química , Água/química
15.
Org Lett ; 21(10): 3554-3557, 2019 05 17.
Artigo em Inglês | MEDLINE | ID: mdl-31058517

RESUMO

The first total synthesis of pactalactam was accomplished using substrate-controlled stereoselective aziridination and regioselective aziridine ring-opening to construct three continuous amino groups on an octasubstituted cyclopentane core. The cyclopentane framework was obtained by ring-closing metathesis and aldol coupling using a l-threonine-derived oxazoline compound. Cyclic urea formation, m-acetylphenyl group introduction by Chan-Lam coupling, and primary alcohol-selective acylation yielded the reported pactalactam structure. The presence of pactalactam in the fermentation broth of pactamycin-producing bacteria was also confirmed.


Assuntos
Álcoois/química , Aziridinas/química , Ciclopentanos/química , Imidazolidinas/síntese química , Pactamicina/síntese química , Acilação , Imidazolidinas/química , Estrutura Molecular , Pactamicina/química
16.
Plant Cell Physiol ; 60(8): 1666-1682, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-31058972

RESUMO

We investigated potential biosynthetic pathways of long chain alkenols (LCAs), long chain alkyl diols (LCDs), and long chain hydroxy fatty acids (LCHFAs) in Nannochloropsis oceanica and Nannochloropsis gaditana, by combining culturing experiments with genomic and transcriptomic analyses. Incubation of Nannochloropsis spp. in the dark for 1 week led to significant increases in the cellular concentrations of LCAs and LCDs in both species. Consistently, 13C-labelled substrate experiments confirmed that both LCA and LCD were actively produced in the dark from C14-18 fatty acids by either condensation or elongation/hydroxylation, although no enzymatic evidence was found for the former pathway. Nannochloropsis spp. did, however, contain (i) multiple polyketide synthases (PKSs) including one type (PKS-Clade II) that might catalyze incomplete fatty acid elongations leading to the formation of 3-OH-fatty acids, (ii) 3-hydroxyacyl dehydratases (HADs), which can possibly form Δ2/Δ3 monounsaturated fatty acids, and (iii) fatty acid elongases (FAEs) that could elongate 3-OH-fatty acids and Δ2/Δ3 monounsaturated fatty acids to longer products. The enzymes responsible for reduction of the long chain fatty acids to LCDs and LCAs are, however, unclear. A putative wax ester synthase/acyl coenzyme A (acyl-CoA): diacylglycerol acyltransferase is likely to be involved in the esterification of LCAs and LCDs in the cell wall. Our data thus provide useful insights in predicting the biosynthetic pathways of LCAs and LCDs in phytoplankton suggesting a key role of FAE and PKS enzymes.


Assuntos
Álcoois/metabolismo , Alcenos/metabolismo , Policetídeo Sintases/metabolismo , Acetiltransferases/metabolismo , Álcoois/química , Alcenos/química , Enoil-CoA Hidratase/metabolismo , Ácidos Graxos Monoinsaturados/metabolismo , Microalgas/enzimologia , Microalgas/metabolismo , Especificidade por Substrato
17.
Org Biomol Chem ; 17(20): 5138-5147, 2019 05 28.
Artigo em Inglês | MEDLINE | ID: mdl-31073571

RESUMO

A series of amino acid derivatives are successfully synthesized via a metal-free C-N coupling reaction of 5-alkoxy-3,4-dihalo-2(5H)-furanones and amino acids. Their structures are well characterized with 1H NMR, 13C NMR, ESI-MS and elemental analysis. As potential linkers of the 2(5H)-furanone unit with other drug moieties containing a hydroxyl or amino group, the effect of amino acids is investigated by comparison with other 2(5H)-furanone compounds by constructing C-O/C-S bonds. The preliminary results of the biological activity assay by the MTT method on a series of cancer cell lines in vitro reveal that the introduction of amino acids basically has no toxic effect. This can lead to these 2(5H)-furanone derivatives being further well-linked with other bioactive moieties with amino or hydroxy groups as expected. Thus, the biological activity assay gives a direction for the design of bioactive 2(5H)-furanones based on these amino acid linkers.


Assuntos
Álcoois/farmacologia , Aminoácidos/farmacologia , Antineoplásicos/farmacologia , Furanos/farmacologia , Álcoois/química , Aminoácidos/síntese química , Aminoácidos/química , Animais , Antineoplásicos/síntese química , Antineoplásicos/química , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Furanos/química , Humanos , Estrutura Molecular , Ratos , Relação Estrutura-Atividade
18.
Chem Commun (Camb) ; 55(44): 6213-6216, 2019 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-31073582

RESUMO

The first example of room temperature non-noble metal homogeneous system catalyzed selective N-alkylation of anilines with alcohols by a bis-NHC manganese complex is presented. This system was applied to a large range of alcohols and anilines, including biologically relevant motifs and challenging methanol. Experimental and computational studies suggest an outer-sphere mechanism for this NHC-Mn system.


Assuntos
Álcoois/química , Compostos de Anilina/química , Compostos Heterocíclicos/química , Manganês/química , Metano/análogos & derivados , Alquilação , Catálise , Metano/química , Temperatura Ambiente
19.
Sensors (Basel) ; 19(10)2019 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-31137611

RESUMO

Transdermal alcohol biosensors have the ability to detect the alcohol that emanates from the bloodstream and diffuses through the skin. However, previous biosensors have suffered from long-term fouling of the sensor element and drift in the resulting sensor readings over time. Here, we report a wearable alcohol sensor platform that solves the problem of sensor fouling by enabling drift-free signals in vivo for up to 24 h and an interchangeable cartridge connection that enables consecutive days of measurement. We demonstrate how alcohol oxidase enzyme and Prussian Blue can be combined to prevent baseline drift above 25 nA, enabling sensitive detection of transdermal alcohol. Laboratory characterization of the enzymatic alcohol sensor demonstrates that the sensor is mass-transfer-limited by a diffusion-limiting membrane of lower permeability than human skin and a linear sensor range between 0 mM and 50 mM. Further, we show continuous transdermal alcohol data recorded with a human subject for two consecutive days. The non-invasive sensor presented here is an objective alternative to the self-reports used commonly to quantify alcohol consumption in research studies.


Assuntos
Oxirredutases do Álcool/química , Álcoois/isolamento & purificação , Técnicas Biossensoriais , Etanol/isolamento & purificação , Álcoois/química , Etanol/química , Ferrocianetos/química , Humanos , Dispositivos Eletrônicos Vestíveis
20.
Biosens Bioelectron ; 137: 161-170, 2019 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-31096082

RESUMO

We report on a wearable tear bioelectronic platform, integrating a microfluidic electrochemical detector into an eyeglasses nose-bridge pad, for non-invasive monitoring of key tear biomarkers. The alcohol-oxidase (AOx) biosensing fluidic system allowed real-time tear collection and direct alcohol measurements in stimulated tears, leading to the first wearable platform for tear alcohol monitoring. Placed outside the eye region this fully wearable tear-sensing platform addresses drawbacks of sensor systems involving direct contact with the eye as the contact lenses platform. Integrating the wireless electronic circuitry into the eyeglasses frame thus yielded a fully portable, convenient-to-use fashionable sensing device. The tear alcohol sensing concept was demonstrated for monitoring of alcohol intake in human subjects over multiple drinking courses, displaying good correlation to parallel BAC measurements. We also demonstrate for the first time the ability to monitor tear glucose outside the eye and the utility of wearable devices for monitoring vitamin nutrients in connection to enzymatic flow detector and rapid voltammetric scanning, respectively. These developments pave the way to build an effective eyeglasses system capable of chemical tear analysis.


Assuntos
Técnicas Biossensoriais , Óculos , Monitorização Fisiológica , Lágrimas/química , Álcoois/química , Álcoois/isolamento & purificação , Glucose/química , Glucose/isolamento & purificação , Humanos , Vitaminas/química , Vitaminas/isolamento & purificação , Dispositivos Eletrônicos Vestíveis
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA