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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.
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
3.
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
4.
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
5.
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
6.
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
7.
Curr Res Microb Sci ; 3: 100129, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35909624

RESUMO

Yeasts of the genus Hanseniaspora gained notoriety in the last years due to their contribution to wine quality, and their loss of several genes, mainly related to DNA repair and cell cycle processes. Based on genomic data from many members of this genus, they have been classified in two well defined clades: the "faster-evolving linage" (FEL) and the "slower-evolving lineage" (SEL). In this context, we had detected that H. vineae exhibited a rapid loss of cell viability in some conditions during the stationary phase compared to H. uvarum and S. cerevisiae. The present work aimed to evaluate the viability and cell cycle progression of representatives of Hanseniaspora species along their growth in an aerobic and discontinuous system. Cell growth, viability and DNA content were determined by turbidity, Trypan Blue staining, and flow cytometry, respectively. Results showed that H. uvarum and H. opuntiae (representing FEL group), and H. osmophila (SEL group) exhibited a typical G1/G0 (1C DNA) arrest during the stationary phase, as S. cerevisiae. Conversely, the three strains studied here of H. vineae (SEL group) arrested at G2/M stages of cell cycle (2C DNA), and lost viability rapidly when enter the stationary phase. These results showed that H. vineae have a unique cell cycle behavior that will contribute as a new eukaryotic model for future studies of genetic determinants of yeast cell cycle control and progression.

8.
J Ethnopharmacol ; 298: 115564, 2022 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-35940467

RESUMO

ETHNOPHARMACOLOGICAL RELEVANCE: Matcha green tea (Camellia sinensis) based-supplements have been widely used since they present a greater content of phenolic compounds than traditional green tea, which is popularly used in the treatment of diabetes. However, there are few studies on the effectiveness and safety of matcha supplements. AIM OF THE STUDY: This work aimed to evaluate the efficacy and safety of this supplement in endothelial cells (EA.hy926) in the hyperglycemic model and in vivo Artemia salina. MATERIALS AND METHODS: To assess the effect of Matcha herbal supplement (MHS), EA. hy926 endothelial cells were treated with 20 µg/mL of MHS for 24 h, in a hyperglycemic medium with 35 mM glucose. After treatment, cells were trypsinized and centrifuged at 4 °C and 47×g for 5 min. The pellet was used to determine the reaction products to thiobarbituric acid and the levels of nitric oxide. Electron transport chain activity and ATP levels were also evaluated. Intracellular pH, apoptosis, and mitochondrial membrane depolarization were evaluated by flow cytometry. MHS chemical characterization was performed by HPLC-UV and total phenolic content analysis. The evaluation of the antioxidant capacity of MHS was performed by 2,2-diphenyl-1-picrylhydrazyl radical scavenger assay. To determine the in vivo acute toxicity of MHS, an A. salina assay was conducted, using 0,2 mL of different concentrations of MHS (10, 50, 100, 250, 500, 750 and 1000 µg/mL). The LD50 values were obtained by interpolation of 50% (y = 50) of the dead individuals in the trend curves. RESULTS: Our data showed that MHS was able to avoid oxidative and nitrosative stress induced by hyperglycemia, demonstrating important antioxidant activity. However, it was observed that MHS reduced up to 90% the activity of the four-electron transport complexes, reducing the ATP production of the endothelial cells. In the toxicity assay performed in Artemia salina, MHS showed mild toxicity (LD50 = 0,4 mg/mL). The major compounds found in MHS were epigallocatechin gallate, epicatechin, rutin, kaempferol, and quercetin. CONCLUSIONS: This data draws attention to the fact that supplements with high content of phenolic compounds, capable of avoiding oxidative and nitrosative stress can have a dual effect and, simultaneously to antioxidant activity, can induce toxicity in different cell types.


Assuntos
Camellia sinensis , Trifosfato de Adenosina , Animais , Antioxidantes/análise , Antioxidantes/farmacologia , Artemia , Camellia sinensis/química , Suplementos Nutricionais/análise , Suplementos Nutricionais/toxicidade , Células Endoteliais , Humanos , Fenóis/análise , Fenóis/toxicidade , Chá/química
9.
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.

10.
J Neurosurg Sci ; 2022 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-35380199

RESUMO

BACKGROUND: Degenerative disc disease (DDD) is a prevalent disorder that brings great incapacity and morbidity to the world's population. Its pathophysiology is not fully understood. DNA damage can influence this process, but so far, there have been few studies to evaluate this topic and its true importance in DDD, as well as whether there is a relation between degeneration grade and DNA damage. The objective of this study is to evaluate the degree of damage to the DNA and the relation to the severity of DDD and measure its response to this insult compared to live/dead cell parameters and reactive oxygen species activity in human discs. METHODS: An experimental study was performed with 15 patients with grade IV or V Pfirrmann classification who underwent spinal surgery. Five patients were operated on two levels, resulting in 20 samples that were submitted to the comet assay to measure DNA damage. Of these, six samples were submitted to flow cytometry, and apoptosis, necrosis, cell membrane integrity, intracellular esterase activity, reactive oxygen species (ROS), caspase 3 and mitochondrial membrane potential were evaluated. RESULTS: All samples had DNA damage, and the average of index damage (ID) was 78.1 (SD ± 65.11) and frequency damage (FD) was 49.3% (SD ± 26,05%). There was no statistical difference between the Pfirrmann grades and genotoxic damage. Likewise, all samples that underwent flow cytometry showed apoptosis and ROS to many different degrees. CONCLUSIONS: DNA damage occurs in high-grade degeneration of human discs and contributes to activation of the apoptosis pathway and ROS production that can accelerate disc degeneration.

11.
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
12.
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
13.
Infect Genet Evol ; 98: 105225, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-35101636

RESUMO

Canine parvovirus type 2 (CPV-2) is a relevant pathogen for dogs and causes a severe disease in carnivore species. CPV-2 reached pandemic proportions after the 1970s with the worldwide dissemination, generating antigenic and genetic variants (CPV-2a, CPV-2b, and CPV-2c) with different pathobiology in comparison with the original type CPV-2. The present study aimed to assess the current global CPV-2 molecular phylogeny and to analyze genetic diversity and temporal spreading of variants from Brazil. A total of 284 CPV-2 whole-genome sequences (WGS) and 684 VP2 complete genes (including 23 obtained in the present study) were compared to analyze phylogenetic relationships. Bayesian coalescent analysis estimated the time to the most recent common ancestor (tMRCA) and the population dynamics of the different CPV-2 lineages in the last decades. The WGS phylogenetic tree demonstrated two main clades disseminated worldwide today. The VP2 gene tree showed a total of four well-defined clades distributed in different geographic regions, including one with CPV-2 sequences exclusive from Brazil. These clades do not have a relationship with the previous classification into CPV-2a, CPV-2b, and CPV-2c, despite some having a predominance of one or more antigenic types. Temporal analysis demonstrated that the main CPV-2 clades evolved within a few years (from the 1980s to 1990s) in North America and they spread worldwide afterwards. Population dynamics analysis demonstrated that CPV-2 presented a major dissemination increase at the end of the 1980s / beginning of the 1990s followed by a period of stability and a second minor increase from 2000 to 2004.


Assuntos
Doenças do Cão/virologia , Variação Genética , Infecções por Parvoviridae/veterinária , Parvovirus Canino/genética , Filogenia , Animais , Brasil , Doenças do Cão/transmissão , Cães , Infecções por Parvoviridae/transmissão , Infecções por Parvoviridae/virologia , Parvovirus Canino/classificação
14.
Int J Food Microbiol ; 347: 109200, 2021 Jun 02.
Artigo em Inglês | MEDLINE | ID: mdl-33894461

RESUMO

The physicochemical characteristics and yeasts diversity in honey samples from 17 species of stingless bees of the genera Nannotrigona, Melipona, Plebeia, Scraptotrigona, and Tetragonisca cultivated in Southern Brazil were determined. The sugar content, moisture, water activity, pH, reducing sugars/total sugar ratio, and total yeast population varied significantly among the honey from the different bee species. The highest yeast population was found in the Plebeia's honey samples and correlated with their high water-activity. Sixteen yeast species were identified based on the nuclear large subunit (26S) ribosomal RNA partial sequences. The genera Starmerella and Zygosaccharomyces were found predominant, with a high prevalence of Starmerella sp., S. etchellsii, and S. apicola. Some yeast species were only identified in honey samples from specific bee species indicating a close relationship between the yeasts and the insects. For the first time, Wickerhamomyces sydowiorum in honey is being reported. In general, the yeast species isolated from stingless bee honey samples demonstrated high osmotolerance and low sugar assimilation.


Assuntos
Abelhas/metabolismo , Mel/microbiologia , Leveduras/classificação , Leveduras/isolamento & purificação , Animais , Biodiversidade , Brasil , Saccharomycetales/genética , Saccharomycetales/isolamento & purificação , Açúcares , Fermento Seco , Leveduras/genética
15.
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
16.
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.

17.
Food Chem ; 326: 126997, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32422511

RESUMO

The increased demand for pesticide-free foods has also increased the search for healthier and environmentally friendly alternatives in agriculture. Essential oils are known to possess natural antifungal properties, becoming a reliable alternative for commercial fungicides, especially for postharvest decay control. However, essential oils are volatile and photodegradable, which reduces their long-term activities. This work presents the development of a lemongrass essential oil-containing poly(lactic acid) nanocapsules. They have shown in vitro antifungal activity against Colletotrichum acutatum and Colletotrichum gloeosporioides with a MIC dosage of 0.1% (v/v) for both phytopathogens. In the in vivo assay with postharvest apples, the ones treated with encapsulated essential oil showed bitter rot lesions three times smaller than the ones treated with non-encapsulated essential oil, or in comparison to the apples in positive control. The methodology led to stable nanocapsules with spherical morphology, a mean diameter of 96.4 nm, and with an encapsulation efficiency of 99%.


Assuntos
Antifúngicos/farmacologia , Colletotrichum/efeitos dos fármacos , Cymbopogon/química , Fungicidas Industriais/farmacologia , Nanocápsulas/química , Óleos Voláteis/química , Poliésteres/farmacologia , Malus/efeitos dos fármacos , Malus/microbiologia , Poliésteres/química
18.
OMICS ; 24(5): 300-309, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-31573385

RESUMO

In the present postgenomic era, the capacity to generate big data has far exceeded the capacity to analyze, contextualize, and make sense of the data in clinical, biological, and ecological applications. There is a great unmet need for automation and algorithms to aid in analyses of big data, in biology in particular. In this context, it is noteworthy that computational methods used to analyze the regulation of bacterial gene expression have in the past focused mainly on Escherichia coli promoters due to the large amount of data available. The challenge and prospects of automation in prediction and recognition of bacteria sequences as promoters have not been properly addressed due to the promoter size and degenerate pattern. We report here an original neural network approach for recognition and prediction of Bacillus subtilis promoters. The artificial neural network used as input 767 B. subtilis promoter sequences, while also aiming at identifying the architecture, provides the most optimal prediction. Two multilayer perceptron neural network architectures offered the highest accuracy: one with five, and another with seven neurons in the hidden layer. Each architecture achieved an accuracy of 98.57% and 97.69%, respectively. The results collectively indicate the promise of the application of neural network approaches to the B. subtilis promoter recognition problem, while also suggesting the broader potential of algorithms for automation of data analyses in the postgenomic era.


Assuntos
Automação/métodos , Bacillus subtilis/genética , Biologia Computacional/métodos , Reconhecimento Automatizado de Padrão/métodos , Regiões Promotoras Genéticas/genética , Análise de Sequência de DNA/métodos , Algoritmos , Escherichia coli/genética , Expressão Gênica/genética , Genes Bacterianos/genética , Genoma Bacteriano/genética , Redes Neurais de Computação
19.
Int J Food Microbiol ; 314: 108383, 2020 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-31698283

RESUMO

Yeasts contribute to anthocyanin extraction during red wine fermentation, but they also reduce wine color by adsorption of pigments on their cell walls. Saccharomyces cerevisiae strains vary on their pigment adsorptive properties, but the mechanisms involved in this phenomenon remain unclear. In this work, we evaluated high, medium and low pigment-adsorbing S. cerevisiae winemaking strains during red wine fermentation. Flow cytometry protocols were devised to measure different populations of yeast and their pigment adsorption in association with other variables such as fermentation rate, cell viability, and cell wall/membrane integrity. The results showed that the high pigment adsorbing strain accumulated anthocyanin towards the end of alcoholic fermentation observed as an increase in the population of fluorescent cells. By contrast, low adsorbing strain displayed a single low adsorbing cell population. Pigment adsorption was negatively correlated with cell viability and cell wall/membrane integrity. Independent of their adsorptive potential during wine fermentation, viable cells displayed a low capacity to adsorb anthocyanins, while permeabilized yeast cells exhibited high pigment adsorption capacity. Our findings suggest that yeast pigment adsorption requires a breach to the inner part of the cell wall, for pigments to access constitutively expressed pigment-binding factors, and that the phenotypic differences among strains are determined by their fermentative live-span and cell wall/membrane integrity. These findings will help to rationalize and optimize the match of winemaking strains and vines.


Assuntos
Antocianinas/metabolismo , Membrana Celular/fisiologia , Parede Celular/fisiologia , Saccharomyces cerevisiae/metabolismo , Vinho/microbiologia , Adsorção , Antocianinas/análise , Membrana Celular/metabolismo , Parede Celular/metabolismo , Fermentação , Viabilidade Microbiana , Pigmentação , Saccharomyces cerevisiae/classificação , Saccharomyces cerevisiae/fisiologia , Especificidade da Espécie , Vinho/análise
20.
Braz. arch. biol. technol ; 63: e20190481, 2020. tab, graf
Artigo em Inglês | LILACS | ID: biblio-1132242

RESUMO

Abstract The objective of this study was to evaluate the biomass and essential oil production of nine populations of poejo (Cunila galioides) cultivated in five agroecological regions of the state of Rio Grande do Sul, under different edaphoclimatic conditions. The experiments were performed in field conditions in Erechim, Caxias do Sul, Pelotas, São Francisco de Paula, and Santa Vitoria do Palmar. The experimental design was completely randomized, with nine populations, eight plants per plot and four repetitions. The following were evaluated: biomass production and essential oil chemical composition and yield. The data underwent ANOVA, followed by Tukey's multiple range test. The adaptability and stability of the populations in the different environments were also evaluated by regression analysis. The results showed great differences between the populations and cultivation sites, with genotype vs. environment interaction. Most populations presented the best biomass production results at Erechim. Pelotas and Santa Vitória do Palmar were the worst locations for poejo production, mainly due to a water deficit occurred during the experiment. The Santa Lucia population presented broad stability and the greatest adaptability to the environments for biomass and essential oil production, but its average production was not satisfactory. The André da Rocha population presented the highest average production of essential oil, and was favored in favorable environments. Regarding essential oil chemical composition, the populations kept stable contents of the major compounds at all locations, with a few variations. In some populations, a higher concentration of sesquiterpenes was observed, which can be attributed to environmental stress.


Assuntos
Óleos de Plantas/química , Óleos Voláteis/química , Biomassa , Lamiaceae/genética , Sesquiterpenos , Solo/química , Clima Tropical , Análise de Regressão , Análise de Variância , Genótipo
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