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1.
Data Brief ; 37: 107233, 2021 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-34235236

RESUMEN

This paper presents the data that estimate the linkages between perceived regulatory support, empathy, moral obligation, social entrepreneurial self-efficacy, perceived social support, and social entrepreneurial intention among Vietnamese students. The scales were adopted from previous studies to develop the questionnaires utilizing a five-Likert scale. The sample collected from 685 undergraduate students from universities in Vietnam. A quantitative approach was utilised to examine the value of data. Specifically, some descriptive statistics was utilized to show the respondents' profiles and characteristics of variables. Cronbach' alpha, exploratory factor analysis and confirmatory factor analysis was used to test the reliability and validity of constructs before estimating path coefficients via structural equational modelling (SEM).

2.
Int J Food Microbiol ; 350: 109242, 2021 Jul 16.
Artículo en Inglés | MEDLINE | ID: mdl-34044228

RESUMEN

Lactic acid fermentation is a traditional process to preserve foods and to modify their organoleptic properties. This process is generally conducted in a spontaneous way, allowing indigenous lactic acid bacteria (LAB) of the matrix and of the environment to compete and grow. The aim of this study was to better characterise LAB strains ability to modify aroma profiles in fruit and vegetable matrices, by focusing on two key enzymatic activities: ß-glucosidase and alcohol dehydrogenase (ADH). Firstly, 200 LAB isolated from Cambodian and Vietnamese fermented foods were screened for their ß-glucosidase activity and duplicate isolates identified through RAPD-PCR analysis were discarded. Thereby, 40 strains were found positive for ß-glucosidase using p-nitrophenyl-ß-D-glucopyranoside as substrate. Among them, 14 displayed an activity greater than 10 nmol/min/mg dry cell. Thirteen were identified as Lactiplantibacillus (L.) plantarum and one as L. pentosus. Secondly, four strains of different phenotypes for ß-glucosidase activity were tested for ADH activity. The highest reduction ability for hexanal and (E)-2-hexenal was obtained for Limosilactobacillus (L.) fermentum V013-1A for which no ß-glucosidase activity was detectable. The three other strains (L. plantarum C022-2B, C022-3B, and V0023-4B2) exhibited a lower reduction ability and only for hexanal. Thirdly, mashed tomatoes were fermented with these four strains individually to evaluate their ability to release volatile compounds from the tomato precursors. Fifty-eight volatile compounds were identified and quantified by HS-SPME/GC-MS. Untreated tomatoes were rich in aldehydes. The tomatoes fermented with L. plantarum strains were rich in ketones whereas those with L. fermentum were rich in alcohols. However, for the generation of terpenoids that provide flower and fruit flavours, our screening of ß-glucosidase activity was not able to explain the differences among the strains. For ADH activity, L. fermentum exhibited a high activity in fermentation as most of the target aldehydes and ketones disappeared and were replaced by their corresponding alcohols. The L. plantarum strains exhibited a lower activity but with an important substrate-selectivity diversity. A better knowledge of the functionality of each LAB strain in the food matrix will permit to predict and shape the aroma profiles of fermented food.


Asunto(s)
Alcohol Deshidrogenasa/metabolismo , Alimentos Fermentados/microbiología , Frutas/microbiología , Lactobacillales/metabolismo , Verduras/microbiología , beta-Glucosidasa/metabolismo , Reactores Biológicos/microbiología , Fermentación , Alimentos Fermentados/análisis , Frutas/química , Cromatografía de Gases y Espectrometría de Masas , Ácido Láctico/análisis , Lactobacillales/aislamiento & purificación , Odorantes/análisis , Técnica del ADN Polimorfo Amplificado Aleatorio
3.
Food Sci Nutr ; 9(3): 1720-1735, 2021 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-33747483

RESUMEN

Severinia buxifolia (Rutaceae) is often used as a traditional medical plant. The present study was carried out to estimate the effects of solvents (petroleum ether and hexane: ethyl acetate) used in liquid-liquid extraction to total terpenoid content (TTC) and in vitro anti-inflammatory activity of the extracts obtained from S. buxifolia bark. The results showed that solvent fractionation increased the TTC compared with crude extracts. The hexane: ethyl acetate bark extract fraction (HEF) had the highest TTC (731.48 µg/ml) in comparison with the petroleum ether bark extract fraction (PEF) (564.81 µg/ml) and the crude extract (CE) (184.26 µg/ml). In addition, one of composition of terpenoid of S. buxifolia, namely ursolic acid, was determined by HPLC method from the crude CE and the fractions PEF and HEF: 2.44 µg/g DW, 3.56 µg/g DW and 5.04 µg/g DW, respectively. The samples had an in vitro anti-inflammatory activity comparable with that of two reference standards (aspirin and indomethacin). Particularly, the HEF fraction had the highest in vitro anti-inflammatory activity (i.e., albumin denaturation: IC50 = 147.91 µg/mL, heat-induced hemolysis: IC50 = 159.91 µg/mL, proteinase inhibition: IC50 = 117.72 µg/mL, and lipoxygenase activity: IC50 = 90.45 µg/mL). Besides, the preliminary experiments of this study were conducted to determine the influences of maceration factors (solvent type, temperature, and time) for S. buxifolia bark extract. The TTC ranged from 453.70 to 842.59 mg linalool/g DW, and the extraction yield from 2.40% to 5.120% in all extracts. Based on TTC and EY, the hexane: acetone mixture is recommended as the optimal solvent to obtain the crude bark extract (CE) at 46°C for 24 hr of maceration. Extracts of S. buxifolia bark are a promising source for the treatment of inflammatory diseases.

4.
Front Microbiol ; 9: 2278, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-30374334

RESUMEN

Fermentation has been used for centuries to produce food in South-East Asia and some foods of this region are famous in the whole world. However, in the twenty first century, issues like food safety and quality must be addressed in a world changing from local business to globalization. In Western countries, the answer to these questions has been made through hygienisation, generalization of the use of starters, specialization of agriculture and use of long-distance transportation. This may have resulted in a loss in the taste and typicity of the products, in an extensive use of antibiotics and other chemicals and eventually, in a loss in the confidence of consumers to the products. The challenges awaiting fermentation in South-East Asia are thus to improve safety and quality in a sustainable system producing tasty and typical fermented products and valorising by-products. At the end of the "AsiFood Erasmus+ project" (www.asifood.org), the goal of this paper is to present and discuss these challenges as addressed by the Tropical Fermentation Network, a group of researchers from universities, research centers and companies in Asia and Europe. This paper presents current actions and prospects on hygienic, environmental, sensorial and nutritional qualities of traditional fermented food including screening of functional bacteria and starters, food safety strategies, research for new antimicrobial compounds, development of more sustainable fermentations and valorisation of by-products. A specificity of this network is also the multidisciplinary approach dealing with microbiology, food, chemical, sensorial, and genetic analyses, biotechnology, food supply chain, consumers and ethnology.

5.
J Bacteriol ; 193(16): 4180-91, 2011 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-21685295

RESUMEN

Bacillus subtilis 168 is resistant to phenolic acids by expression of an inducible enzyme, the phenolic acid decarboxylase (PadC), that decarboxylates these acids into less toxic vinyl derivatives. In the phenolic acid stress response (PASR), the repressor of padC, PadR, is inactivated by these acids. Inactivation of PadR is followed by a strong expression of padC. To elucidate the functional interaction between PadR and the padC promoter, we performed (i) footprinting assays to identify the region protected by PadR, (ii) electrophoretic mobility shift assays (EMSAs) with a modified padC promoter protected region to determine the interacting sequences, and (iii) random mutagenesis of padR to identify amino acid residues essential for the function of PadR. We identified an important consensus dyad sequence called IR1-2 (ATGT-8N-ACAT) overlapping a second dyad element (GTGT-8N-ACAT) that we named dIR1-2bis. The entire dIR1-2bis/IR1-2 sequence permits binding of two PadR dimers in EMSAs, which may be observed for bacteria grown under noninduced conditions where the padC promoter is completely repressed. Three groups of modified PadRs giving a PASR phenotype were characterized in vivo. The DNA sequences of certain mutant padR alleles indicate that important residues are all located in the region containing the coiled-coil leucine zipper domain that is involved in dimerization. These substitutions reduce the affinity of PadR binding to the padC promoter. Of particular interest are residue L128, located at the center of the putative coiled-coil leucine zipper domain, and residue E97, which is conserved among all PadRs.


Asunto(s)
Bacillus subtilis/efectos de los fármacos , Bacillus subtilis/metabolismo , Proteínas Bacterianas/metabolismo , Regulación Bacteriana de la Expresión Génica/efectos de los fármacos , Hidroxibenzoatos/farmacología , Estrés Fisiológico/efectos de los fármacos , Bacillus subtilis/fisiología , Proteínas Bacterianas/genética , Ensayo de Cambio de Movilidad Electroforética , Regiones Promotoras Genéticas/efectos de los fármacos , Regiones Promotoras Genéticas/fisiología , Unión Proteica , Estructura Secundaria de Proteína
6.
J Bacteriol ; 190(9): 3213-24, 2008 May.
Artículo en Inglés | MEDLINE | ID: mdl-18326577

RESUMEN

In Bacillus subtilis, several phenolic acids specifically induce expression of padC, encoding a phenolic acid decarboxylase that converts these antimicrobial compounds into vinyl derivatives. padC forms an operon with a putative coding sequence of unknown function, yveFG, and this coding sequence does not appear to be involved in the phenolic acid stress response (PASR). To identify putative regulators involved in the PASR, random transposon mutagenesis, combined with two different screens, was performed. PadR, a negative transcriptional regulator of padC expression, was identified. padR is not located in the vicinity of padC, and the expression of padR is low and appears constitutive. This is in contrast with what occurs in other gram-positive bacteria, in which padR is autoregulated and induced by phenolic acids. Further screening of the transposon library failed to identify genes other than padR involved in the PASR. Modest inactivation of padR by phenolic acids was obtained in recombinant Escherichia coli expressing padC and padR, and this translates into induction of decarboxylase activity. Gel shift promoter binding assays performed with and without MgCl(2), and with and without phenolic acids, demonstrated that phenolic acids were able to abolish the binding of PadR to the yveFG-padC promoter in the absence of MgCl(2). Altogether, our results indicate that (i) PadR is inactivated directly by phenolic acids in vitro, (ii) inhibition of PadR in response to phenolic acids may occur without the need for a sensor-like effector in B. subtilis, and (iii) phenolic acids are able to modulate PadR activity in E. coli in the absence of any additional effector.


Asunto(s)
Bacillus subtilis/genética , Proteínas Bacterianas/genética , Carboxiliasas/genética , Regulación Bacteriana de la Expresión Génica , Regulación Enzimológica de la Expresión Génica , Hidroxibenzoatos/metabolismo , Proteínas Represoras/metabolismo , Secuencia de Aminoácidos , Bacillus subtilis/enzimología , Secuencia de Bases , Ensayo de Cambio de Movilidad Electroforética , Hidroxibenzoatos/farmacología , Datos de Secuencia Molecular , Proteínas Represoras/antagonistas & inhibidores , Proteínas Represoras/genética
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