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1.
Yeast ; 40(12): 640-650, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37997429

RESUMO

Yeasts have been widely used as a model to better understand cell cycle mechanisms and how nutritional and genetic factors can impact cell cycle progression. While nitrogen scarcity is well known to modulate cell cycle progression, the relevance of nitrogen excess for microorganisms has been overlooked. In our previous work, we observed an absence of proper entry into the quiescent state in Hanseniaspora vineae and identified a potential link between this behavior and nitrogen availability. Furthermore, the Hanseniaspora genus has gained attention due to a significant loss of genes associated with DNA repair and cell cycle. Thus, the aim of our study was to investigate the effects of varying nitrogen concentrations on H. vineae's cell cycle progression. Our findings demonstrated that nitrogen excess, regardless of the source, disrupts cell cycle progression and induces G2/M arrest in H. vineae after reaching the stationary phase. Additionally, we observed a viability decline in H. vineae cells in an ammonium-dependent manner, accompanied by increased production of reactive oxygen species, mitochondrial hyperpolarization, intracellular acidification, and DNA fragmentation. Overall, our study highlights the events of the cell cycle arrest in H. vineae induced by nitrogen excess and attempts to elucidate the possible mechanism triggering this absence of proper entry into the quiescent state.


Assuntos
Hanseniaspora , Hanseniaspora/metabolismo , Apoptose , Pontos de Checagem da Fase G2 do Ciclo Celular , Linhagem Celular Tumoral , Nitrogênio/metabolismo
2.
Food Microbiol ; 110: 104171, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-36462827

RESUMO

In this study, we followed the yeast and wine behaviour during the second fermentation and subsequent lees ageing of sparkling wines produced by Traditional and Charmat methods at an industrial scale. During this period, we conducted physicochemical, microbiological, gene expression, and marker analyses of characteristics related to wine ageing. Our results show that the yeast behaviour during the fermentation is similar in both methods. However, after fermentation, there is a faster decrease in yeast vitality and viability in the Charmat method, together with an increase in the expression of autophagy-related genes (AMS1, APE1, and ATG8). We relate these factors to ageing with the continuous homogenization of the liquid practised in the Charmat method, and static ageing with the lees concentrated at the bottom of the bottle performed in the Traditional method. Despite the variation in yeast viability during ageing, there are no differences in soluble proteins, free amino nitrogen, total phenols, antioxidant activity, and colour evolution between the wines produced by the two methods, assuming few differences over the time that monitoring was conducted.


Assuntos
Vinho , Saccharomyces cerevisiae/genética , Fermentação , Autofagia
3.
Plant Dis ; 107(9): 2643-2652, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-36724095

RESUMO

Plasmopara viticola, the agent of grapevine downy mildew, causes enormous economic damage, and its control is primarily based on the use of synthetic fungicides. The European Union policies promote reducing reliance on synthetic plant protection products. Biocontrol agents such as Trichoderma spp. constitute a resource for the development of biopesticides. Trichoderma spp. produce secondary metabolites such as peptaibols, but the poor water solubility of peptaibols limits their practical use as agrochemicals. To identify new potential bio-inspired molecules effective against P. viticola, various water-soluble peptide analogs of the peptaibol trichogin were synthesized. In grapevine leaf disk assays, the peptides analogs at a concentration of 50 µM completely prevented P. viticola infection after zoosporangia inoculation. Microscopic observations of one of the most effective peptides showed that it causes membrane lysis and cytoplasmic granulation in both zoosporangia and zoospores. Among the effective peptides, 4r was selected for a 2-year field trial experiment. In the vineyard, the peptide administered at 100 µM (equivalent to 129.3 g/ha) significantly reduced the disease incidence and severity on both leaves and bunches, with protection levels similar to those obtained using a cupric fungicide. In the second-year field trial, reduced dosages of the peptide were also tested, and even at the peptide concentration reduced by 50 or 75%, a significant decrease in the disease incidence and severity was obtained at the end of the trial. The peptide did not show any phytotoxic effect. Previously, peptide 4r had been demonstrated to be active against other fungal pathogens, including the grapevine fungus Botrytis cinerea. Thus, this peptide may be a candidate for a broad-spectrum fungicide whose biological properties deserve further investigation.


Assuntos
Oomicetos , Peronospora , Trichoderma , Vitis , Peptaibols/metabolismo , Peptaibols/farmacologia , Fazendas , Vitis/microbiologia , Doenças das Plantas/prevenção & controle , Doenças das Plantas/microbiologia , Água
4.
An Acad Bras Cienc ; 94(2): e20200394, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35319598

RESUMO

Alternaria alternata causes leaf spot and black rot diseases in leaves and grapes of grapevines, respectively, and leads to huge economic losses in table grapes production. As natural antifungal agents, essential oils (EOs), which are generally recognized as safe substances, shows strong antifungal activity against fungal phytopathogens. The aim of this study was to determine the chemical composition of Eucalyptus staigeriana EO and its in vitro and in vivo effects against A. alternata. The major compounds of E. staigeriana EO were citral (34.32%, of which 21.83% geranial and 12.49% neral), limonene (20.60%) and 1,8-cineole (12.33%). E. staigeriana EO exhibited the highest inhibitory activity on mycelial growth and conidial germination at 1 µL mL-1. Moreover, the EO was able to reduce the incidence and severity of leaf spot disease in leaves and black rot disease in table grapes caused by A. alternata. These results represent a possible alternative to reduce the use of synthetic molecules for the control of diseases in postharvest of table grapes and in vineyard.


Assuntos
Eucalyptus , Óleos Voláteis , Vitis , Alternaria , Antifúngicos/química , Antifúngicos/farmacologia , Óleos Voláteis/farmacologia , Doenças das Plantas/microbiologia , Doenças das Plantas/prevenção & controle
5.
Pestic Biochem Physiol ; 182: 105032, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35249653

RESUMO

Chlorothalonil is a broad-spectrum fungicide largely used for the control of several diseases of grapevines. With a moderate persistence in plants, soil and, water, it can be carried to grape musts, particularly when applied to control grape rot diseases. This work aimed to determine the effect of chlorothalonil on Saccharomyces cerevisiae under fermentative conditions using a flow cytometry approach. Yeasts were cultivated in synthetic must with different concentrations of chlorothalonil (0 to 60 µM) and evaluated for culture-ability, membrane integrity, reactive oxygen species (ROS) accumulation, mitochondrial membrane potential, metacaspase activity, ATP, nonprotein SH and, SH-proteins. The results confirmed the oxidation of nonprotein SH, including glutathione, and the binding of the fungicide with sulfhydryl proteins, which led to changes in the cell and mitochondrial membranes that result in the necrotic death of part of the yeast population, and a reduction in metabolic activity. Moreover, the reduction in glutathione-SH concentration was responsible for the increase in ROS which in turn triggers metacaspase-dependent apoptotic cell death. Cells that escape death adapt and began to grow and ferment after a dose-dependent lag-phase period, exhibiting an almost normal fermentative behavior thereafter. Moreover, was observed unexpected protection of chlorothalonil sub-dosages on yeast cell membrane integrity during alcoholic fermentation. This study contributed insights into how chlorothalonil leads the non-target organism S. cerevisiae to cell death and explores the effect of the fungicide during alcoholic fermentation.


Assuntos
Proteínas de Saccharomyces cerevisiae , Saccharomyces cerevisiae , Fermentação , Nitrilas/farmacologia , Proteínas de Saccharomyces cerevisiae/metabolismo
6.
J Food Sci Technol ; 59(9): 3530-3539, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35875230

RESUMO

Pyment is a type of mead that is produced from the alcoholic fermentation of a honey solution with the addition of grape juice. Due to the demand for new beverages, pyment can be a profitable alternative for both grape and honey producers. Therefore, this work aimed to characterize the aromatic and physicochemical composition of pyments. The pyments were prepared with addition of 10, 20 and 30% of Moscato juice, and compared with Moscato wine and traditional mead. The results showed an increase in the fermentation rates of Moscato-pyments, indicating that the addition of Moscato juice reverses the low fermentative vigor often reported in mead fermentations. Physicochemical parameters showed an increase in total acidity and a decrease in residual sugar and alcohol, depending on Moscato juice concentration. Moscato-pyments showed an intermediate concentration of volatile compounds between the traditional mead and Moscato wine, with a better balance between fruity, floral and buttery, manifesting characteristic aromas of wines made with Moscato grapes and simultaneously, exposing characteristic aromas of honey. The sensory analysis reveals a significant difference between mead, pyments and Moscato wine. In general, pyments were considered, by the panelists, as the most equilibrated with intermediary aroma intensity, floral, fruity and honey aromas, and good persistence in the mouth.

7.
World J Microbiol Biotechnol ; 37(3): 42, 2021 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-33547564

RESUMO

Essential oils and their main components, monoterpenes, have been proven to be important alternatives for the control of pathogenic and spoiling microorganisms, but the mode of action of these compounds is poorly understood. This work aimed to determine the mode of action of citral and geraniol on the model yeast Saccharomyces cerevisiae using a flow cytometry approach. Exponentially growing yeast cells were treated with different concentrations of citral and geraniol for 3 h, and evaluated for cell wall susceptibility to glucanase, membrane integrity, reactive oxygen species (ROS) accumulation, mitochondrial membrane potential, and metacaspase activity. Results provide strong evidence that citral and geraniol acute fungicidal activity against Saccharomyces cells involves the loss of membrane and cell wall integrity resulting in a dose-dependent apoptotic/necrotic cell death. However, yeast cells that escape this first cell membrane disruption, particularly evident on sub-lethal concentration, die by metacaspase-mediated apoptosis induced by the accumulation of intracellular ROS. The deleted mutant on the yca1 gene showed high tolerance to citral and geraniol.


Assuntos
Monoterpenos Acíclicos/farmacologia , Caspases/genética , Proteínas de Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/crescimento & desenvolvimento , Apoptose , Membrana Celular/metabolismo , Farmacorresistência Fúngica , Citometria de Fluxo , Deleção de Genes , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Saccharomyces cerevisiae/efeitos dos fármacos , Saccharomyces cerevisiae/genética
8.
J Food Sci Technol ; 57(8): 2840-2851, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32624591

RESUMO

Mead is an ancient alcoholic beverage produced through the fermentation of a diluted solution of honey. Due to the peculiar and varied composition of honey, mead production faces several problems, such as slow or stuck fermentations mainly due to the low nitrogen concentration, lack of uniformity of the final product and the production of unpleasant aromas. In this context, this work aimed to select low nitrogen-demand yeast strains and evaluate their potential for the production of mead. Therefore, among 21 commercial wine yeast strains, 5 were selected based on their fermentative behavior at low assimilable nitrogen concentrations. The selected strains were further evaluated for their contributions in meads produced with limited nitrogen availability, and the results showed significant differences on some physicochemical parameters like biomass production, residual sugars, glycerol concentration, and fermentative rate. Moreover, meads obtained with selected strains differed in the concentration of several volatile compounds. The volatile compounds concentration and the principal component analysis based on odor activity values allowed separating strains into three groups. In general, S. cerevisiae var bayanus strains (QA23, Spark, and AWRI-R2) were the largest producers of aromatic compounds, particularly those with floral and fruity descriptors. The selection of yeast strains with low nitrogen-demand and different volatile compounds production can be explored by mead makers to limit fermentation problems and obtain characteristic products.

9.
J Mol Recognit ; 32(5): e2770, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30458580

RESUMO

Promoters are DNA sequences located upstream of the transcription start site of genes. In bacteria, the RNA polymerase enzyme requires additional subunits, called sigma factors (σ) to begin specific gene transcription in distinct environmental conditions. Currently, promoter prediction still poses many challenges due to the characteristics of these sequences. In this paper, the nucleotide content of Escherichia coli promoter sequences, related to five alternative σ factors, was analyzed by a machine learning technique in order to provide profiles according to the σ factor which recognizes them. For this, the clustering technique was applied since it is a viable method for finding hidden patterns on a data set. As a result, 20 groups of sequences were formed, and, aided by the Weblogo tool, it was possible to determine sequence profiles. These found patterns should be considered for implementing computational prediction tools. In addition, evidence was found of an overlap between the functions of the genes regulated by different σ factors, suggesting that DNA structural properties are also essential parameters for further studies.


Assuntos
Escherichia coli/enzimologia , Escherichia coli/genética , Regiões Promotoras Genéticas , Fator sigma/genética , Algoritmos , Sequência de Bases , RNA Polimerases Dirigidas por DNA/genética , RNA Polimerases Dirigidas por DNA/metabolismo , Proteínas de Escherichia coli/genética , Proteínas de Escherichia coli/metabolismo , Nucleotídeos/análise , Fator sigma/metabolismo , Transcrição Gênica
10.
J Sci Food Agric ; 99(14): 6552-6561, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31321781

RESUMO

BACKGROUND: Essential oils (EOs) are volatile natural compounds produced by plant secondary metabolism, and some of them exhibit antimicrobial activity. The objective of the present study was to determine the chemical composition the EOs of Eucalyptus staigeriana and Eucalyptus globulus, and their effect in vitro and in vivo against Botrytis cinerea and Colletotrichum acutatum, the most important fungal rot diseases of grapes. Moreover, grapes collected from field experiments were used to evaluate the impact of the alternative control on the alcoholic fermentation and wine composition. RESULTS: The major compound of E. staigeriana EO were citral 30.91% (19.74% geranial, 11.17% neral), 1.8-cineole (24.59%) and limonene (19.47%), while 1.8-cineole represented 68.26% of E. globulus EO. The two EOs showed in vitro antifungal activity against both pathogens. Eucalyptus staigeriana EO exhibited the highest activity inhibiting mycelial growth (MG) and conidial germination at 0.5 µL mL-1 . Moreover, this EO was able to reduce the incidence and severity of grey rot caused by B. cinerea and the severity of ripe rot caused by C. acutatum The alternative control did not significantly influence alcoholic fermentation, the physicochemical characteristics, and the volatile composition of wines. CONCLUSION: These results are promising and indicate that E. staigeriana EO might be further investigated as a natural alternative for the control of fungal rots on wine grapes. © 2019 Society of Chemical Industry.


Assuntos
Antifúngicos/farmacologia , Eucalyptus/química , Óleos Voláteis/farmacologia , Doenças das Plantas/prevenção & controle , Extratos Vegetais/farmacologia , Vitis/microbiologia , Antifúngicos/química , Botrytis/efeitos dos fármacos , Botrytis/crescimento & desenvolvimento , Colletotrichum/efeitos dos fármacos , Colletotrichum/crescimento & desenvolvimento , Testes de Sensibilidade Microbiana , Micélio/efeitos dos fármacos , Micélio/crescimento & desenvolvimento , Óleos Voláteis/química , Doenças das Plantas/microbiologia , Extratos Vegetais/química
11.
Pestic Biochem Physiol ; 149: 137-142, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30033009

RESUMO

Dithianon is a broad-spectrum anthraquinone fungicide used to control several diseases of grapes, apples, and other fruits and vegetables. Its mode of action is described as multi-site and associated to thiol-reactivity. As other fungicides can affect non-phytopathogenic organisms as yeasts and bacteria, with impact on microbial population, diversity, and fermentation processes. In this context, we study the effect of dithianon on the model organism and fermentative yeast Saccharomyces cerevisiae in order to elucidate the mechanisms involved in yeast cell death., and explain its interference on wine fermentation kinetics. Thus for, we analyzed cellular protein and non-protein thiols, membrane and cell wall integrity, reactive oxygen species accumulation, mitochondrial membrane potential, and phosphatidylserine externalization. The results showed that when exponentially aerobic growing cells of S. cerevisiae are submitted to acute dithianon treatment they loss cell wall and membrane integrity, dying by necrosis, and this behavior is associated to a depletion of reduced proteic and non-proteic thiol groups. We also detected an important increase of cellular reactive oxygen species (ROS) associated to mitochondrial membrane potential modifications on dithianon treated cells. ROS accumulation was not associated to apoptotic cell death, but can be responsible for intracellular damages. Moreover, necrotic cell death induced by dithianon explains its effect on the kinetics of wine fermentations.


Assuntos
Antraquinonas/farmacologia , Morte Celular/efeitos dos fármacos , Fungicidas Industriais/farmacologia , Saccharomyces cerevisiae/efeitos dos fármacos , Parede Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Fermentação , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Necrose , Fosfatidilserinas/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Saccharomyces cerevisiae/citologia , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Compostos de Sulfidrila/metabolismo , Vitis/metabolismo , Vinho
12.
World J Microbiol Biotechnol ; 33(8): 159, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28748404

RESUMO

Captan is one of the most widely used broad-spectrum fungicide applied to control several early and late diseases of grapes, apples, and other fruits and vegetables, and as other phthalimide fungicides is defined as a multisite compound with thiol-reactivity. Captan can affect non-target organisms as yeasts, modifying microbial populations and fermentation processes. In this study, we asked whether Captan thiol-reactivity and other mechanisms are involved in acute Captan-induced cell death on aerobic growing Saccharomyces cerevisiae. Thus for, we analyze cellular protein and non-protein thiols, cell membrane integrity, reactive oxygen species accumulation, phosphatidylserine externalization, and apoptotic mutants behavior. The results showed that when submitted to acute Captan treatment most cells lost their membrane integrity and died by necrosis due to Captan reaction with thiols. However, part of the cells, even maintaining their membrane integrity, lost their culture ability. These cells showed an apoptotic behavior that may be the result of non-protein thiol depletion and consequent increase of reactive oxygen species (ROS). ROS accumulation triggers a metacaspase-dependent apoptotic cascade, as shown by the higher viability of the yca1-deleted mutant. Together, necrosis and apoptosis are responsible for the high mortality detected after acute Captan treatment of aerobically growing cells of S. cerevisiae.


Assuntos
Apoptose/efeitos dos fármacos , Captana/farmacologia , Morte Celular/efeitos dos fármacos , Saccharomyces cerevisiae/efeitos dos fármacos , Membrana Celular/efeitos dos fármacos , Fermentação , Fungicidas Industriais/farmacologia , Viabilidade Microbiana/efeitos dos fármacos , Mutação , Necrose , Espécies Reativas de Oxigênio/metabolismo , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/crescimento & desenvolvimento , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo , Compostos de Sulfidrila/metabolismo
13.
World J Microbiol Biotechnol ; 31(5): 755-62, 2015 May.
Artigo em Inglês | MEDLINE | ID: mdl-25721421

RESUMO

This study analyses the effect of the crude enzymatic extract produced by Kluyveromyces marxianus (EEB) in the maceration and clarification of juice produced from Ives (Vitis labrusca) grapes compared to the commercial enzyme preparation Pectinex(®)Ultra Color (PEC). Treatments were conducted with a total pectinolytic activity of 1 U/mL of fruit juice, at 40 °C, for 60 min. After the enzymatic treatment, the juices were evaluated with respect to yield, viscosity, and degree of clarification, as well as the effect of the enzymes on polyphenol concentration, anthocyanins, and juice color. The results showed that both EEB and PEC increase yield, reduce viscosity and contribute to the clarification of grape juice. After enzyme treatment with the EEB preparation, the extraction yield increased 28.02 % and decreased 50.70 % in viscosity during the maceration of the pulp. During the juice production process clarification increased 11.91 %. With PEC, higher values for these parameters: 42.36, 63.20, and 26.81 % respectively, were achieved. The addition of EEB resulted in grape juice with better color intensity and extraction of phenolic compounds and anthocyanins. Considering all comparison criteria, the enzymatic extract of K. marxianus NRRL-Y-7571 can potentially be used in the production of juice.


Assuntos
Bebidas/microbiologia , Hidrolases/isolamento & purificação , Hidrolases/metabolismo , Kluyveromyces/enzimologia , Kluyveromyces/metabolismo , Pectinas/metabolismo , Vitis/microbiologia , Temperatura
14.
Biologicals ; 42(1): 22-8, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24172230

RESUMO

The advent of modern high-throughput sequencing has made it possible to generate vast quantities of genomic sequence data. However, the processing of this volume of information, including prediction of gene-coding and regulatory sequences remains an important bottleneck in bioinformatics research. In this work, we integrated DNA duplex stability into the repertoire of a Neural Network (NN) capable of predicting promoter regions with augmented accuracy, specificity and sensitivity. We took our method beyond a simplistic analysis based on a single sigma subunit of RNA polymerase, incorporating the six main sigma-subunits of Escherichia coli. This methodology employed successfully re-discovered known promoter sequences recognized by E. coli RNA polymerase subunits σ(24), σ(28), σ(32), σ(38), σ(54) and σ(70), with highlighted accuracies for σ(28)- and σ(54)- dependent promoter sequences (values obtained were 80% and 78.8%, respectively). Furthermore, the discrimination of promoters according to the σ factor made it possible to extract functional commonalities for the genes expressed by each type of promoter. The DNA duplex stability rises as a distinctive feature which improves the recognition and classification of σ(28)- and σ(54)- dependent promoter sequences. The findings presented in this report underscore the usefulness of including DNA biophysical parameters into NN learning algorithms to increase accuracy, specificity and sensitivity in promoter beyond what is accomplished based on sequence alone.


Assuntos
DNA Bacteriano/genética , Escherichia coli/genética , Regiões Promotoras Genéticas , Fator sigma/genética
15.
World J Microbiol Biotechnol ; 30(5): 1541-7, 2014 May.
Artigo em Inglês | MEDLINE | ID: mdl-24347085

RESUMO

The effect of the addition of enzymatic extract of Kluyveromyces marxianus NRRL-Y-7571 during the maceration and fermentation steps of Cabernet Sauvignon wine production was evaluated. The results obtained in the analytical determinations of the wines showed levels within the limits established by legislation and similar to values found in other studies. The results show that by adding the enzyme to the red wines these showed color characteristics considered to be superior to those of the control wine and accelerated the extraction of phenolic compounds and anthocyanins. It was observed that by using the commercial enzyme preparation there was an increase of 15 % in polyphenol content compared to the control wine and an increase of 28 % when the crude enzyme extract was used. Anthocyanin content in the wine increased after treatment with the commercial enzyme preparation (10 %) and with the use of the crude enzymatic extract (22 %). Considering all comparison criteria, the K. marxianus enzymatic extract showed results statistically similar or superior to those obtained with the commercial enzyme preparation.


Assuntos
Antocianinas/análise , Kluyveromyces/isolamento & purificação , Poligalacturonase/metabolismo , Polifenóis/análise , Vinho/análise , Fermentação , Manipulação de Alimentos/métodos , Proteínas Fúngicas/metabolismo , Kluyveromyces/classificação , Kluyveromyces/enzimologia , Vinho/microbiologia
16.
ScientificWorldJournal ; 2013: 519858, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23983637

RESUMO

The present work aimed to analyze the alkaloid content of the ethanolic extract of Tabernaemontana catharinensis (Apocynaceae family) and its fractions as well as to evaluate their antioxidant and anticholinesterasic activities. The analyses of the ethanolic extract of T. catharinensis by mass spectrometry allowed identifying the presence of the alkaloids 16-epi-affinine, coronaridine-hydroxyindolenine, voachalotine, voacristine-hydroxyindolenine, and 12-methoxy-n-methyl-voachalotine, as well as an alkaloid with m/z 385.21 whose spectrum suggests a derivative of voacristine or voacangine. The extract and its alkaloid rich fractions showed antioxidant activity, especially those that contain the alkaloid m/z 385.21 or 16-epi-affinine with DPPH scavenging activity (IC50) between 37.18 and 74.69 µg/mL. Moreover, the extract and its fractions exhibited anticholinesterasic activity, particularly the fractions characterized by the presence of 12-methoxy-n-methyl-voachalotine, with IC50 = 2.1 to 2.5 µg/mL. Fractions with 16-epi-affinine combined good antioxidant (IC50 = 65.59 to 74.69 µg/mL) and anticholinesterasic (IC50 = 7.7 to 8.3 µg/mL) activities, representing an option for further studies aimed at treating neurodegenerative diseases.


Assuntos
Antioxidantes/farmacologia , Inibidores da Colinesterase/farmacologia , Tabernaemontana/química , Antioxidantes/química , Inibidores da Colinesterase/química , Cromatografia em Camada Fina , Concentração Inibidora 50 , Cinética , Espectrometria de Massas por Ionização por Electrospray
17.
World J Microbiol Biotechnol ; 29(6): 1019-27, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23355138

RESUMO

The industry of fine wines and also locally consumed table wines is emerging in Brazil with an increasing volume and economic impact. Enologists in this region currently lack information about the prevalence and characteristics of spoilage yeasts, which may contaminate and potentially undervalue Brazilian wines. Herein, we analyzed 50 local red wines including 27 fine wines (V. vinifera) and 23 table wines (V. labrusca). Presumptive spoilage yeasts were isolated on differential medium, and classified by RFLP-PCR and sequencing of the ITS1-5.8S-ITS2 and D1/D2 26S rDNA loci. The prevalence of spoilage yeasts in fine wines (11 %) was comparable to that reported in European and US wines, and significantly lower than that observed for local table wines (70 %). The majority of isolates belonged to Brettanomyces bruxelliensis, followed by Pichia guillermondii, and more rarely Candida wickerhamii and Trigonopsis cantarelli. The Brettanomyces isolates varied greatly in off-flavor production, displayed ethanol tolerance (>10 % by volume), tolerated sulfite (≥0.68 mg/l mSO2), and 39 % of them grew on ethanol as sole carbon source. We discuss the causes and consequences of spoilage yeasts in relation to the Brazilian wine industry.


Assuntos
Saccharomyces/isolamento & purificação , Saccharomyces/metabolismo , Vinho/análise , Vinho/microbiologia , Brasil , Análise por Conglomerados , DNA Fúngico/química , DNA Fúngico/genética , DNA Ribossômico/química , DNA Ribossômico/genética , DNA Espaçador Ribossômico/química , DNA Espaçador Ribossômico/genética , Genes de RNAr , Dados de Sequência Molecular , Filogenia , Reação em Cadeia da Polimerase , Polimorfismo de Fragmento de Restrição , RNA Fúngico/genética , RNA Ribossômico/genética , RNA Ribossômico 5,8S/genética , Saccharomyces/classificação , Saccharomyces/genética , Análise de Sequência de DNA
18.
Dent Mater ; 39(9): 763-769, 2023 09.
Artigo em Inglês | MEDLINE | ID: mdl-37400298

RESUMO

OBJECTIVES: to characterize the effects of graphene oxide (GO) on polymethyl methacrylate's (PMMA) reliability and lifetime. The hypothesis tested was that GO would increase both Weibull parameters and decreased strength degradation over time. METHODS: PMMA disks containing GO (0.01, 0.05, 0.1, or 0.5 wt%) were subjected to a biaxial flexural test to determine the Weibull parameters (m: modulus of Weibull; σ0: characteristic strength; n = 30 at 1 MPa/s) and slow crack growth (SCG) parameters (n: subcritical crack growth susceptibility coefficient, σf0: scaling parameter; n = 10 at 10-2, 10-1, 101, 100 and 102 MPa/s). Strength-probability-time (SPT) diagrams were plotted by merging SCG and Weibull parameters. RESULTS: There was no significant difference in the m value of all materials. However, 0.5 GO presented the lowest σ0, whereas all other groups were similar. The lowest n value obtained for all GO-modified PMMA groups (27.4 for 0.05 GO) was higher than the Control (15.6). The strength degradation predicted after 15 years for Control was 12%, followed by 0.01 GO (7%), 0.05 GO (9%), 0.1 GO (5%), and 0.5 GO (1%). SIGNIFICANCE: The hypothesis was partially accepted as GO increased PMMA's fatigue resistance and lifetime but did not significantly improve its Weibull parameters. GO added to PMMA did not significantly affect the initial strength and reliability but significantly increased PMMA's predicted lifetime. All the GO-containing groups presented higher resistance to fracture at all times analyzed compared with the Control, with the best overall results observed for 0.1 GO.


Assuntos
Grafite , Polimetil Metacrilato , Teste de Materiais , Reprodutibilidade dos Testes , Propriedades de Superfície , Cerâmica
19.
Sci Rep ; 13(1): 9781, 2023 Jun 16.
Artigo em Inglês | MEDLINE | ID: mdl-37328566

RESUMO

The conventional methods for ethanol recovery in low concentrations from diluted aqueous solutions are limited by the high energy consumed. Therefore, developing a cost-effective advanced membrane process for ethanol recovery and concentration is still necessary. A gas stripping-assisted vapour permeation (GSVP) process was applied to concentrate ethanol by the selective removal of water using hydrophilic graphene oxide (GO) membranes. Silicon carbide porous tubes were internally coated with GO-based membranes with an average thickness of 1.1 µm as a selective layer. Dry N2 was bubbled into the feed solution, carrying the saturated vapours to the separation module. The modified GSVP process was implemented to recover ethanol at lower temperatures than direct distillation and close-ended GSVP processes. The performance of the membrane-coated tubes was evaluated as a function of temperature and feed concentration, ranging from 23 to 60 °C and 10 wt% to 50 wt%. Distillates with 67 wt% and 87 wt% were obtained from feeds with 10 and 50 wt% ethanol at 50 °C, respectively. The evaporation energy spent by the modified GSVP process using GO-coated SiC tubes was 22% and 31% lower than the traditional distillation and vapour stripping processes.


Assuntos
Etanol , Grafite , Água , Gases
20.
Res Vet Sci ; 162: 104962, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37542932

RESUMO

Periodontal disease is a chronic condition characterized by bacterial adhesion, followed by biofilm formation, and subsequently by an inflammatory process that progresses to gingivitis and later to periodontitis. The variations in the oral microbiota have been associated with the progression of this disease. This study evaluated the alteration of the cultivable oral microbiota in dogs with different oral health status. Thirty dogs were selected and divided into three groups: healthy, gingivitis, and periodontitis. The collected oral samples were seeded, and colonies with distinct phenotypic characteristics were isolated and classified using sequencing of the 16S rRNA gene. The DNA sequences were aligned, and a phylogenetic tree was constructed. Simpson's diversity index was calculated, and a dissimilarity matrix based on the Jaccard similarity index was used to plot a principal coordinate analysis. A total of 119 bacteria with different colony morphologies were isolated and classified into 4 phyla, 29 genera, and 45 species based on phylogenetic analysis. The results indicated an increase in bacteria belonging to the Proteobacteria phylum and a less extended decrease in Actinobacteria, Firmicutes, and Bacteroidetes phyla in dogs with periodontal disease (gingivitis and periodontitis) compared to healthy dogs. Representatives of the genera Neisseria sp., Corynebacterium sp., Pasteurella sp., and Moraxella sp. increased through the worsening of the periodontal disease, while Staphylococcus sp. decreased. All groups exhibited moderate to high levels of biodiversity index, and the plotted PCoA show a clear separation in the oral microbiome of dogs with periodontitis compared to dogs with gingivitis and the healthy group.


Assuntos
Doenças do Cão , Gengivite , Doenças Periodontais , Periodontite , Cães , Animais , RNA Ribossômico 16S/genética , Filogenia , Periodontite/veterinária , Gengivite/veterinária , Bactérias , Doenças Periodontais/veterinária , Doenças do Cão/microbiologia
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