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1.
PLoS One ; 15(11): e0242692, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33227009

RESUMO

Interactions between microbial symbionts influence their demography and that of their hosts. Taylor's power law (TL)-a well-established relationship between population size mean and variance across space and time-may help to unveil the factors and processes that determine symbiont multiplications. Recent studies suggest pervasive interactions between symbionts in Drosophila melanogaster. We used this system to investigate theoretical predictions regarding the effects of interspecific interactions on TL parameters. We assayed twenty natural strains of bacteria in the presence and absence of a strain of yeast using an ecologically realistic set-up with D. melanogaster larvae reared in natural fruit. Yeast presence led to a small increase in bacterial cell numbers; bacterial strain identity largely affected yeast multiplication. The spatial version of TL held among bacterial and yeast populations with slopes of 2. However, contrary to theoretical prediction, the facilitation of bacterial symbionts by yeast had no detectable effect on TL's parameters. These results shed new light on the nature of D. melanogaster's symbiosis with yeast and bacteria. They further reveal the complexity of investigating TL with microorganisms.


Assuntos
Bactérias/crescimento & desenvolvimento , Simbiose/fisiologia , Leveduras/crescimento & desenvolvimento , Animais , Bactérias/classificação , Drosophila melanogaster , Larva/microbiologia , Leveduras/classificação
2.
J Dairy Sci ; 103(11): 9946-9957, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32896415

RESUMO

In this study, we evaluated the efficacy of 3 commercial protective cultures designated PC1 (Lactobacillus spp.), PC2 (Lactobacillus rhamnosus), and PC3 (Lactobacillus rhamnosus) as biopreservatives in queso fresco (QF) against 9 yeast strains (Candida zeylanoides, Clavispora lusitaniae, Debaryomyces hansenii, Debaryomyces prosopidis, Kluyveromyces marxianus, Meyerozyma guilliermondii, Pichia fermentans, Rhodotorula mucilaginosa, and Torulaspora delbrueckii) and 11 mold strains (Aspergillus cibarius, Aureobasidium pullulans, Penicillium chrysogenum, Penicillium citrinum, Penicillium commune, Penicillium decumbens, Penicillium roqueforti, Mucor genevensis, Mucor racemosus, Phoma dimorpha, and Trichoderma amazonicum). All fungal spoilage strains were previously isolated from dairy processing environments. A positive control (C) with no protective culture was included. Fungal spoilage organisms were inoculated on cheese surfaces at an inoculum level of 20 cfu/g, and cheeses were stored at 6 ± 2°C throughout the study. For yeast enumeration, cheeses were sampled on d 0, 7, 14, and 21 postinoculation. Significant inhibition was detected for each yeast strain by comparing yeast counts for each cheese treated with protective culture against the control cheese using one-way ANOVA with Bonferroni correction performed individually at d 7, 14, and 21 postinoculation. Mold growth was visually observed and imaged weekly through 70 d postinoculation. Whereas PC3 inhibited Cl. lusitaniae, Mey. guilliermondii, and Ph. dimorpha, PC2 inhibited the outgrowth of Cl. lusitaniae, D. hansenii, and Ph. dimorpha. Protective culture 1 had the broadest spectrum of efficacy across yeast and molds, delaying spoilage caused by 4 distinct yeast strains (Cl. lusitaniae, D. hansenii, D. prosopidis, and Mey. guilliermondii), and inhibiting visible growth of 2 mold strains (P. chrysogenum and Ph. dimorpha). Results demonstrated that commercial protective cultures vary in performance, as indicated by the breadth of mold and yeast inhibition at both the genus and species level. This study suggests that manufacturers looking into using protective cultures should investigate their efficacy against specific fungal strains of concern.


Assuntos
Queijo/microbiologia , Contaminação de Alimentos/prevenção & controle , Microbiologia de Alimentos , Fungos/crescimento & desenvolvimento , Lactobacillus/fisiologia , Leveduras/crescimento & desenvolvimento , Animais
3.
Food Microbiol ; 91: 103513, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32539960

RESUMO

This work aimed to estimate the inactivation kinetic parameters of four potential beer spoilage bacteria (Lactobacillus brevis DSM 6235, Lactobacillus casei ATCC 334, Pediococcus damnosus DSM 20289 and Pediococcus damnosus ATCC 29358) inoculated in brewing yeast submitted to acid washing with purposes of yeast recycle. The experiments were conducted at 4 °C in solutions with pH 1.5, pH 2, and pH 3 adjusted employing 85% phosphoric acid. The acid washing treatment of brewing yeasts in the most common pH used (pH 2.0) demanded almost 50 min for the first decimal reduction (δ) of L. brevis DSM 6235. Sensible strains to acid washing such as P. damnosus DSM 20289 demanded almost 70 min for 4 log reductions to be achieved. On the other hand, pH reduction of the acid washing from 2.0 to 1.5 allowed 4 log reduction of L. brevis DSM 6235) to be obtained in less than 50 min, without ruining brewer's yeast viability. Acid washing in pH 1.5 is a viable method for the inactivation of bacterial contaminants of brewing yeasts. Recycling of brewing yeasts through this approach may contribute to a more sustainable and environmental-friendly industry.


Assuntos
Cerveja/microbiologia , Lactobacillaceae/efeitos dos fármacos , Ácidos Fosfóricos/farmacologia , Leveduras/crescimento & desenvolvimento , Reatores Biológicos/microbiologia , Fermentação , Contaminação de Alimentos/prevenção & controle , Microbiologia de Alimentos , Concentração de Íons de Hidrogênio , Cinética , Lactobacillaceae/classificação , Lactobacillaceae/crescimento & desenvolvimento , Lactobacillaceae/metabolismo , Leveduras/metabolismo
4.
J Appl Microbiol ; 129(5): 1163-1172, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32392369

RESUMO

AIMS: This study evaluated the effects of exogenous lactic acid bacteria (LAB) on silage fermentation and bacterial community of reed canary grass (RCG) straw. METHODS AND RESULTS: The leaf, stem and whole crop of RCG straw were separately ensiled in small bag silos, without (control) or with inoculation of two exogenous LAB (LP, Lactobacillus plantarum; LB, Lactobacillus buchneri), and stored at ambient temperature of <20°C. Inoculation of exogenous LAB decreased (P < 0·05) bacterial alpha diversity and shifted (P < 0·05) bacterial community compositions, but did not change (P> 0·05) the relative abundance of Lactobacillus. Particularly, inoculation of LB increased (P < 0·05) acetic acid and propionic acid contents, decreased (P < 0·05) butyric acid (BA) and ammonia-N contents, separated (P < 0·05) the bacterial community in silage. However, the exogenous LAB inoculated silages were characterized by main distribution of yeasts, presence of undesirable bacterial genera such as Clostridium and high levels of BA and ammonia-N. CONCLUSION: Inoculation of exogenous LAB exerted a limited influence on the silage fermentation and bacterial community compositions of RCG straw on the Qinghai-Tibetan Plateau. SIGNIFICANCE AND IMPACT OF THE STUDY: Commercial LAB inoculants are not always efficient on enhancing silage quality and stability. Thus, an alternative additive for inhibiting undesirable microbes during storage is important to improve RCG silage quality on the Qinghai-Tibetan Plateau.


Assuntos
Lactobacillales/fisiologia , Microbiota , Phalaris/microbiologia , Silagem/microbiologia , Amônia/análise , Amônia/metabolismo , Bactérias/classificação , Bactérias/crescimento & desenvolvimento , Bactérias/metabolismo , Ácidos Graxos Voláteis/análise , Ácidos Graxos Voláteis/metabolismo , Fermentação , Lactobacillales/metabolismo , Phalaris/química , Silagem/análise , Tibet , Leveduras/classificação , Leveduras/crescimento & desenvolvimento , Leveduras/metabolismo
5.
PLoS One ; 15(3): e0230269, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32176885

RESUMO

Secondary peat swamp forest (PSF) arise by degradation of primary PSF as a result of fire and human activities. Yeasts diversity of Kuan Kreng (KK) and Rayong Botanical Garden (RBG) PSF, which are two secondary PSF in southern and in eastern Thailand, respectively, were investigated. Yeasts were isolated from soil and peat soil by the dilution plate and enrichment techniques. From six samples collected from KK PSF, 35 strains were obtained, and they were identified based on the sequence analysis of the D1/D2 region of the large subunit (LSU) rRNA gene 13 species in 12 genera, and one potential new species of the genus Galactomyces were detected. Thirty-two strains were obtained from six samples collected from RBG PSF and 26 strains were identified as 13 known yeast species in 11 genera, whereas six strains were found to represent two potential new species of the genera Papiliotrema and Moesziomyces. Among yeast strains isolated from KK PSF, the number of strains in the phylum Ascomycota and Basidiomycota were equal, whereas there were slightly fewer strains in Ascomycota than in Basidiomycota among the strains obtained from RBG PSF. The yeast strains were evaluated for their antagonistic activities against fungal pathogens which cause rice diseases (Fusarium moniliforme, Helminthosporium oryzae, Rhizoctonia solani, Curvularia lunata and Pyricularia grisea) and postharvest disease of fruits (Phytophthora palmivora, Lasiodiplodia theobromae and Colletotrichum gloeosporioides). Twelve strains of seven species were found to be antagonistic yeast strains. Starmerella kuoi DMKU-SPS13-6, Hanseniaspora lindneri DMKU ESS10-9 and Piskurozyma taiwanensis DMKU-SPS12-2 capable to inhibit R. solani by 70.1-76.2%, Wickerhamomyces anomalus DMKU SPS6-1 and three Rhodotorula taiwanensis strains (DMKU SPS8-1, DMKU ESS9-3, DMKU SPS9-2) inhibited C. lunata by 69.8-71.9%, Hanseniaspora lindneri DMKU ESS10-9 and Scheffersomyces spartinae DMKU SPS9-3 inhibited P. grisea by 81.9-84.4% and four Papiliotrema laurentii strains (DMKU-SPS15-1, DMKU-ESS11-2, DMKU-ESS8-2, DMKU-ESS6-4) inhibited P. palmivora by 53.2-59.5%.


Assuntos
Florestas , Frutas/microbiologia , Doenças das Plantas/microbiologia , Solo , Áreas Alagadas , Leveduras/fisiologia , Geografia , Filogenia , Microbiologia do Solo , Tailândia , Leveduras/classificação , Leveduras/genética , Leveduras/crescimento & desenvolvimento
6.
Int J Food Microbiol ; 321: 108544, 2020 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-32086129

RESUMO

The microbial ecology in the fermentation of Australian coffee beans was investigated in this study. Pulped coffee beans were kept underwater for 36 h before air dried. Samples were collected periodically, and the microbial communities were analyzed by culture-dependent and independent methods. Changes in sugars, organic acids and microbial metabolites in the mucilage and endosperm of the coffee beans during fermentation were monitored by HPLC. Culture-dependent methods identified 6 yeast and 17 bacterial species, while the culture-independent methods, multiple-step total direct DNA extraction and high throughput sequencing, identified 212 fungal and 40 bacterial species. Most of the microbial species in the community have been reported for wet fermentation of coffee beans in other parts of the world, but the yeast Pichia kudriavzevii was isolated for the first time in wet coffee bean fermentation. The bacterial community was dominated by aerobic mesophilic bacteria (AMB) with Citrobacter being the predominant genus. Hanseniaspora uvarum and Pichia kudriavzevii were the predominant yeasts while Leuconostoc mesenteroides and Lactococcus lactis were the predominant LAB. The yeasts and bacteria grew significantly during fermentation, utilizing sugars in the mucilage and produced mannitol, glycerol, and lactic acid, leading to a significant decrease in pH. The results of this study provided a preliminary understanding of the microbial ecology of wet coffee fermentation under Australian conditions. Further studies are needed to explore the impact of microbial growth and metabolism on coffee quality, especially flavour.


Assuntos
Coffea/microbiologia , Manipulação de Alimentos/métodos , Microbiota , Austrália , Bactérias/classificação , Bactérias/crescimento & desenvolvimento , Bactérias/isolamento & purificação , Bactérias/metabolismo , Coffea/química , Café/química , Fermentação , Microbiologia de Alimentos , Microbiota/genética , Sementes/química , Sementes/microbiologia , Leveduras/classificação , Leveduras/crescimento & desenvolvimento , Leveduras/isolamento & purificação , Leveduras/metabolismo
7.
Appl Microbiol Biotechnol ; 104(7): 3133-3144, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32076780

RESUMO

Six local isolates of yeasts were screened for cell mass and lipid production in mixed glucose and xylose medium. Candida tropicalis SY005 and Trichosporon (Apiotrichum) loubieri SY006 showed significant lipid accumulation of 24.6% and 32% (dry cell weight), respectively when grown in medium containing equal mass of both the sugars. SY005 produced relatively higher cell mass of 9.66 gL-1 due to higher rate of sugar consumption, which raised the lipid productivity of the organism to 0.792 gL-1day-1 as compared to 0.446 gL-1day-1 in SY006. When grown with each sugar separately, the xylose consumption rate of SY005 was found to be 0.55 gL-1 h-1 after 4 days as compared to 0.52 gL-1 h-1 for SY006. Transcript expression of the high affinity xylose transporter (Cthaxt), xylose reductase (Ctxyl1), and xylitol dehydrogenase (Ctxyl2) of SY005 was monitored to unravel such high rate of sugar consumption. Expression of all the three genes was observed to vary in mixed sugars with Cthaxt exhibiting the highest expression in presence of only xylose. Expression levels of both Ctxyl1 and Ctxyl2, involved in xylose catabolism, were maximum during 24-48 h of growth, indicating that xylose utilization started in the presence of glucose, which was depleted in the medium after 96 h. Together, the present study documents that C. tropicalis SY005 consumes xylose concomitant to glucose during early period of growth, and it is a promising yeast strain for viable production of storage lipid or other high-value oleochemicals utilizing lignocellulose hydrolysate.


Assuntos
Candida tropicalis/metabolismo , Lipídeos/biossíntese , Xilose/metabolismo , Candida tropicalis/genética , Candida tropicalis/crescimento & desenvolvimento , Meios de Cultura/química , Fermentação , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Regulação Fúngica da Expressão Gênica , Glucose/análise , Glucose/metabolismo , Especificidade da Espécie , Trichosporon/genética , Trichosporon/crescimento & desenvolvimento , Trichosporon/metabolismo , Xilose/análise , Leveduras/classificação , Leveduras/genética , Leveduras/crescimento & desenvolvimento , Leveduras/metabolismo
8.
Carbohydr Res ; 488: 107902, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31911362

RESUMO

Trehalose 6-phosphate (Tre6P) is an important intermediate for trehalose biosynthesis. Recent researches have revealed that Tre6P is an endogenous signaling molecule that regulates plant development and stress responses. The necessity of Tre6P in physiological studies is expected to be increasing. To achieve the cost-effective production of Tre6P, a novel approach is required. In this study, we utilized trehalose 6-phosphate phosphorylase (TrePP) from Lactococcus lactis to produce Tre6P. In the reverse phosphorolysis by the TrePP, 91.9 mM Tre6P was produced from 100 mM ß-glucose 1-phosphate (ß-Glc1P) and 100 mM glucose 6-phosphate (Glc6P). The one-pot reaction of TrePP and maltose phosphorylase (MP) enabled production of 65 mM Tre6P from 100 mM maltose, 100 mM Glc6P, and 20 mM inorganic phosphate. Addition of ß-phosphoglucomutase to this reaction produced Glc6P from ß-Glc1P and thus reduced requirement of Glc6P as a starting material. Within the range of 20-469 mM inorganic phosphate tested, the 54 mM concentration yielded the highest amount of Tre6P (33 mM). Addition of yeast increased the yield because of its glucose consumption. Finally, from 100 mmol maltose and 60 mmol inorganic phosphate, we successfully achieved production of 37.5 mmol Tre6P in a one-pot reaction (100 mL), and 9.4 g Tre6P dipotassium salt was obtained.


Assuntos
Glucosiltransferases/metabolismo , Lactococcus lactis/enzimologia , Fosfatos Açúcares/biossíntese , Trealose/análogos & derivados , Leveduras/crescimento & desenvolvimento , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Metabolismo dos Carboidratos , Clonagem Molecular , Glucose-6-Fosfatase/metabolismo , Glucofosfatos/metabolismo , Glucosiltransferases/genética , Lactococcus lactis/genética , Fosfatos/metabolismo , Trealose/biossíntese , Leveduras/genética
9.
Food Chem ; 305: 125461, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31505412

RESUMO

The quality of fermented soybeans can be determined by diverse metabolites produced by microorganisms. Mass spectrometry-based metabolomic approach was applied to investigate the differences in volatile and non-volatile metabolite profiles of fermented soybeans by different microorganisms [e.g., molds, yeasts, lactic acid bacteria (LAB), and other bacteria]. The partial least squares-discriminant analysis (PLS-DA) for volatile metabolites profiles indicated that the fungi group (mold/yeast) was clearly discriminated from the bacteria group (bacteria/LAB). The metabolic pathways related to the formation of volatile metabolites also differed according to microorganisms. In particular, the formation of branched-chain aliphatic alcohols and esters increased in the fungi group, while that of volatiles derived from fatty acids was superior in the bacteria group. In addition, we could determine the microorganism-specific metabolites using a correlation network analysis. This study can provide the fundamental knowledge on the metabolic differences according to the type of microorganisms in fermented soybeans.


Assuntos
Bactérias/crescimento & desenvolvimento , Alimentos e Bebidas Fermentados/análise , Metabolômica/métodos , Soja/metabolismo , Leveduras/crescimento & desenvolvimento , Bactérias/metabolismo , Análise Discriminante , Ésteres/metabolismo , Ácidos Graxos/metabolismo , Álcoois Graxos/metabolismo , Cromatografia Gasosa-Espectrometria de Massas , Análise dos Mínimos Quadrados , Leveduras/metabolismo
10.
Food Microbiol ; 85: 103287, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31500707

RESUMO

Wine-related non-Saccharomyces yeasts are becoming more widely used in oenological practice for their ability to confer wine a more complex satisfying aroma, but their metabolism remains unknown. Our study explored the nitrogen utilisation profile of three popular non-Saccharomyces species, Torulaspora delbrueckii, Metschnikowia pulcherrima and Metschnikowia fructicola. The nitrogen source preferences to support growth and fermentation as well as the uptake order of different nitrogen sources during wine fermentation were investigated. While T. delbrueckii and S. cerevisiae strains shared the same nitrogen source preferences, Metschnikowia sp. Displayed a lower capacity to efficiently use the preferred nitrogen compounds, but were able to assimilate a wider range of amino acids. During alcoholic fermentation, the non-Saccharomyces strains consumed different nitrogen sources in a similar order as S. cerevisiae, but not as quickly. Furthermore, when all the nitrogen sources were supplied in the same amount, their assimilation order was similarly affected for both S. cerevisiae and non-Saccharomyces strains. Under this condition, the rate of nitrogen source consumption of non-Saccharomyces strains and S. cerevisiae was comparable. Overall, this study expands our understanding about the preferences and consumption rates of individual nitrogen sources by the investigated non-Saccharomyces yeasts in a wine environment. This knowledge provides useful information for a more efficient exploitation of non-Saccharomyces strains that improves the management of the wine fermentation.


Assuntos
Fermentação , Nitrogênio/metabolismo , Vinho/microbiologia , Leveduras/crescimento & desenvolvimento , Leveduras/metabolismo , Aminoácidos/metabolismo , Metschnikowia/crescimento & desenvolvimento , Odorantes , Saccharomyces cerevisiae , Torulaspora/crescimento & desenvolvimento
11.
Bioprocess Biosyst Eng ; 43(4): 723-736, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31883034

RESUMO

The production of microbial protein in the form of yeast grown on lignocellulosic sugars and nitrogen-rich industrial residues is an attractive approach for reducing dependency on animal and plant protein. Growth media composed of enzymatically saccharified sulfite-pulped spruce wood, enzymatic hydrolysates of poultry by-products and urea were used for the production of single-cell protein. Strains of three different yeast species, Cyberlindnera jadinii, Wickerhamomyces anomalus and Blastobotrys adeninivorans, were cultivated aerobically using repeated fed-batch fermentation up to 25 L scale. Wickerhamomyces anomalus was the most efficient yeast with yields of 0.6 g of cell dry weight and 0.3 g of protein per gram of glucose, with cell and protein productivities of 3.92 g/L/h and 1.87 g/L/h, respectively. Using the conditions developed here for producing W. anomalus, it would take 25 industrial (200 m3) continuously operated fermenters to replace 10% of the fish feed protein used in Norway.


Assuntos
Técnicas de Cultura Celular por Lotes , Biomassa , Reatores Biológicos , Meios de Cultura , Lignina/química , Picea/química , Leveduras/crescimento & desenvolvimento , Animais , Meios de Cultura/química , Meios de Cultura/farmacologia , Aves Domésticas
12.
Food Funct ; 10(12): 8208-8217, 2019 Dec 11.
Artigo em Inglês | MEDLINE | ID: mdl-31701990

RESUMO

Research supports the theory that the microbiome of plants and mushrooms produce potent activators of pathogen recognition receptors which are principal contributors to the stimulation of macrophages. We have previously reported that the in vitro macrophage stimulatory activity of water-soluble extracts from 13 different types of edible mushrooms is predominantly due to bacterial components originating from the naturally occurring bacterial communities within these materials. The purpose of the current study was to further investigate the bacterial-dependent activity of the water-soluble extracts and assess whether these 13 types of mushrooms contain water-insoluble beta glucans that activate the dectin-1b signaling pathway. Activity of the water-soluble extracts was predominantly due to Toll-like receptor 2 (TLR2) and TLR4 agonists. For dectin-1b-dependent activity (indicative of water-insoluble beta glucans), culinary mushrooms (Agaricus bisporus varieties) were essentially inactive, whereas most of the medicinal mushrooms (Lentinula edodes, Grifola frondosa, Hypsizygus marmoreus varieties, Flammulina velutipes) exhibited potent activation. A. bisporus samples with no detectable dectin-1b-dependent activity had yeast colony forming units that were 687 times lower than L. edodes exhibiting high activity, indicating that the active insoluble beta glucans are derived from colonizing yeast. In addition, co-stimulation of macrophages with the TLR agonists and insoluble beta glucan was found to result in a synergistic enhancement of in vitro cytokine production. Taken together, these findings indicate that the in vitro macrophage activating potential of edible mushrooms is due to the collaborative interaction of water-soluble TLR agonists (derived from colonizing bacteria) and water-insoluble beta glucans (derived from colonizing yeast).


Assuntos
Agaricales/química , Bactérias/química , Lectinas Tipo C/imunologia , Ativação de Macrófagos/efeitos dos fármacos , Macrófagos/imunologia , Extratos Vegetais/farmacologia , Receptores Toll-Like/imunologia , Verduras/microbiologia , Leveduras/química , beta-Glucanas/farmacologia , Agaricales/classificação , Animais , Bactérias/crescimento & desenvolvimento , Bactérias/metabolismo , Lectinas Tipo C/genética , Macrófagos/efeitos dos fármacos , Camundongos , Extratos Vegetais/química , Células RAW 264.7 , Receptores Toll-Like/agonistas , Receptores Toll-Like/genética , Verduras/química , Verduras/classificação , Leveduras/crescimento & desenvolvimento , Leveduras/metabolismo , beta-Glucanas/metabolismo
13.
Int J Mol Sci ; 20(22)2019 Nov 08.
Artigo em Inglês | MEDLINE | ID: mdl-31717311

RESUMO

The virulence of bacterial outer membrane vesicles (OMVs) contributes to innate microbial defense. Limited data report their role in interspecies reactions. There are no data about the relevance of OMVs in bacterial-yeast communication. We hypothesized that model Moraxella catarrhalis OMVs may orchestrate the susceptibility of pathogenic bacteria and yeasts to cationic peptides (polymyxin B) and serum complement. Using growth kinetic curve and time-kill assay we found that OMVs protect Candida albicans against polymyxin B-dependent fungicidal action in combination with fluconazole. We showed that OMVs preserve the virulent filamentous phenotype of yeasts in the presence of both antifungal drugs. We demonstrated that bacteria including Haemophilus influenza, Acinetobacter baumannii, and Pseudomonas aeruginosa coincubated with OMVs are protected against membrane targeting agents. The high susceptibility of OMV-associated bacteria to polymyxin B excluded the direct way of protection, suggesting rather the fusion mechanisms. High-performance liquid chromatography-ultraviolet spectroscopy (HPLC-UV) and zeta-potential measurement revealed a high sequestration capacity (up to 95%) of OMVs against model cationic peptide accompanied by an increase in surface electrical charge. We presented the first experimental evidence that bacterial OMVs by sequestering of cationic peptides may protect pathogenic yeast against combined action of antifungal drugs. Our findings identify OMVs as important inter-kingdom players.


Assuntos
Bactérias/patogenicidade , Membrana Celular/metabolismo , Proteínas do Sistema Complemento/farmacologia , Vesículas Extracelulares/metabolismo , Peptídeos/farmacologia , Soro/metabolismo , Leveduras/patogenicidade , Bactérias/efeitos dos fármacos , Bactérias/crescimento & desenvolvimento , Cátions , Membrana Celular/efeitos dos fármacos , Membrana Celular/ultraestrutura , Permeabilidade da Membrana Celular/efeitos dos fármacos , Vesículas Extracelulares/efeitos dos fármacos , Vesículas Extracelulares/ultraestrutura , Fluconazol/farmacologia , Humanos , Testes de Sensibilidade Microbiana , Viabilidade Microbiana/efeitos dos fármacos , Moraxella/metabolismo , Polimixina B/farmacologia , Eletricidade Estática , Virulência/efeitos dos fármacos , Leveduras/efeitos dos fármacos , Leveduras/crescimento & desenvolvimento
14.
BMC Complement Altern Med ; 19(1): 288, 2019 Oct 28.
Artigo em Inglês | MEDLINE | ID: mdl-31660943

RESUMO

BACKGROUND: Extracts from medicinal plants with phytochemicals with known antimicrobial properties can be an effective adjunct in the complex treatment of infectious diseases. This study aimed to evaluate the antimicrobial activity of wormwood extracts collected in Kazakhstan (Artemisia gmelinii Weber ex Stechm.), along with their phytochemical analysis. METHODS: The ethanolic and chloroform extracts were subjected to HPLC combined with quadrupole time-of-flight mass spectrometry method. For quantitative assessment of antimicrobial activity, minimal inhibitory concentration (MIC) of the tested extracts was determined by micro-dilution broth method for the panel of the reference microorganisms. Minimal bactericidal concentration (MBC) or minimal fungicidal concentration (MFC) were also determined. RESULTS: LC/MS analysis showed the presence of 13 compounds in the tested extracts, including flavonoids: apigenin, luteolin, rutin, two O-methylated flavonols (isorhamnetin, rhamnazine), coumarin compounds (umbelliferone, scopoletin and scopolin (scopoletin 7-glucoside), 3-hydroxycoumarin and 4-hydroxycoumarin), chlorogenic acid and two dicaffeoylquinic acid isomers. Quantitative HPLC analysis showed that umbelliferone was dominant in the chloroform extract while chlorogenic acid was identified as a main compound in the ethanolic extract. The antibacterial and antifungal activity of chloroform and ethanolic extracts was comparable. The most sensitive were the Gram-positive bacteria represented by staphylococci, Micrococcus luteus and Bacillus spp. (MIC = 1.25-5 mg/ml) and yeasts represented by Candida spp. (MIC = 2.5-5 mg/ml), irrespective of the assayed extract. CONCLUSIONS: Extracts of wormwood Artemisia gmelinii have shown a wide spectrum of antibacterial and antifungal activity. Luteolin, rutin, isorhamnetin and scopolin were identified in A. gmelinii species for the first time. The determining of the most potential compounds of Artemisia gmelinii can be used to develop effective antibacterial and antifungal agents.


Assuntos
Anti-Infecciosos/farmacologia , Artemisia/química , Compostos Fitoquímicos/farmacologia , Extratos Vegetais/farmacologia , Anti-Infecciosos/química , Bactérias/efeitos dos fármacos , Bactérias/crescimento & desenvolvimento , Ácido Clorogênico/química , Ácido Clorogênico/isolamento & purificação , Ácido Clorogênico/farmacologia , Flavonoides/química , Flavonoides/isolamento & purificação , Flavonoides/farmacologia , Testes de Sensibilidade Microbiana , Compostos Fitoquímicos/química , Compostos Fitoquímicos/isolamento & purificação , Extratos Vegetais/química , Extratos Vegetais/isolamento & purificação , Plantas Medicinais/química , Leveduras/efeitos dos fármacos , Leveduras/crescimento & desenvolvimento
15.
Bull Exp Biol Med ; 167(6): 763-766, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31655997

RESUMO

We studied the effect of albumin (human serum, bovine serum, and ovalbumin) on Candida albicans, Cryptococcus neoformans, E. coli, and Staphylococcus aureus cells. Antimicrobial activity was evaluated by microscopy, inoculation, and spectrophotometry. All three albumins showed antimicrobial activity against all studied cultures and their effect was dose-dependent. At concentrations of serum albumins close to physiological (50 mg/ml), the cells of microorganisms were destroyed with the formation of debris vesicles, while at lower concentrations (10 mg/ml), only cell membrane integrity was impaired. According to spectrophotometry, activity of the human serum albumin in a physiological concentration against the studied microorganisms was close to the activity of native human serum.


Assuntos
Albuminas/farmacologia , Anti-Infecciosos/farmacologia , Bactérias/efeitos dos fármacos , Leveduras/efeitos dos fármacos , Animais , Bactérias/crescimento & desenvolvimento , Candida albicans , Bovinos , Cryptococcus neoformans , Relação Dose-Resposta a Droga , Escherichia coli , Humanos , Testes de Sensibilidade Microbiana , Staphylococcus aureus , Leveduras/crescimento & desenvolvimento
16.
J Food Sci ; 84(10): 2944-2954, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31553057

RESUMO

The objective of this study was to isolate and identify the microorganisms, especially yeasts and molds, related to the improvement of beef quality during dry-aging of beef through microbiome analysis, and to examine the possibility of using them as starter culture strains to improve the efficiency of dry-aging beef production. Beef sirloins were dry-aged for 28 days using different wind speeds (0, 2.5, and 5 m/s) at 1 to 3 °C and 75% relative humidity, and microbial compositions were confirmed by microbiome analysis. Mold and yeast samples were plated on potato dextrose agar supplemented with 10% tartaric acid, and the isolated colonies were identified by DNA sequencing. The isolates were subjected to microbial characterization (morphological characterization, growth condition, and enzyme activity). Microbiome analysis showed that the dominant microorganisms were molds and yeasts identified as Pilaira anomala SMFM201611 and Debaryomyces hansenii SMFM201707. Pilaira anomala SMFM201611 and D. hansenii SMFM201707 were inoculated into 24 sirloins of the lowest grade. All samples were dry-aged for 0, 14, 21, and 28 days and analyzed for microbial growth, pH, shear force, ultrastructure, and flavor compounds (free amino acids and free fatty acids). Inoculation with P. anomala SMFM201611 and D. hansenii SMFM201707 improved tenderness and cause the breakdown of myofibrils by proteolysis. Both microorganisms also produced free amino acids and fatty acids through proteolytic and lipolytic activities. These results indicate that P. anomala SMFM201611 and D. hansenii SMFM201707 isolated and identified from dry-aged beef can improve the quality of low-grade beef during dry-aging. PRACTICAL APPLICATION: During dry-aging, mold and yeast improve the quality of dry-aged beef. Pilaira anomala SMFM201611 and Debaryomyces hansenii SMFM201707 isolated from dry-aged beef can improve tenderness by breaking down myofibrils. Both microorganisms improve flavor by producing free fatty acids and amino acids, and the taste and aroma characteristics of low-grade beef may be improved during the dry-aging process.


Assuntos
Fungos/isolamento & purificação , Microbiota , Carne Vermelha/microbiologia , Leveduras/isolamento & purificação , Animais , Bovinos , Aromatizantes/análise , Microbiologia de Alimentos , Fungos/classificação , Fungos/genética , Fungos/crescimento & desenvolvimento , Humanos , Produtos da Carne/análise , Odorantes/análise , Melhoria de Qualidade , Carne Vermelha/análise , Análise de Sequência de DNA , Paladar , Leveduras/classificação , Leveduras/genética , Leveduras/crescimento & desenvolvimento
17.
EMBO J ; 38(17): e101859, 2019 09 02.
Artigo em Inglês | MEDLINE | ID: mdl-31368592

RESUMO

The phytohormone abscisic acid (ABA) regulates plant responses to abiotic stress, such as drought and high osmotic conditions. The multitude of functionally redundant components involved in ABA signaling poses a major challenge for elucidating individual contributions to the response selectivity and sensitivity of the pathway. Here, we reconstructed single ABA signaling pathways in yeast for combinatorial analysis of ABA receptors and coreceptors, downstream-acting SnRK2 protein kinases, and transcription factors. The analysis shows that some ABA receptors stimulate the pathway even in the absence of ABA and that SnRK2s are major determinants of ABA responsiveness by differing in the ligand-dependent control. Five SnRK2s, including SnRK2.4 known to be active under osmotic stress in plants, activated ABA-responsive transcription factors and were regulated by ABA receptor complexes in yeast. In the plant tissue, SnRK2.4 and ABA receptors competed for coreceptor interaction in an ABA-dependent manner consistent with a tight integration of SnRK2.4 into the ABA signaling pathway. The study establishes the suitability of the yeast system for the dissection of core signaling cascades and opens up future avenues of research on ligand-receptor regulation.


Assuntos
Ácido Abscísico/metabolismo , Proteínas de Arabidopsis/genética , Arabidopsis/metabolismo , Leveduras/crescimento & desenvolvimento , Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Vias Biossintéticas , Regulação da Expressão Gênica de Plantas , Pressão Osmótica , Fosforilação , Engenharia de Proteínas , Proteínas Serina-Treonina Quinases/genética , Leveduras/genética
18.
Appl Microbiol Biotechnol ; 103(20): 8293-8300, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31402425

RESUMO

This review summarizes the current knowledge on the importance and role of lipids in wine yeast fermentation. Lipids play an important role in membrane structure, adaptation to stress, or as signaling molecules. They are also essential nutrients whose availability can vary depending on winemaking technology, with major effects on yeast alcoholic fermentation. Moreover, lipid supplementation can greatly stimulate the formation of yeast volatile metabolites.


Assuntos
Fermentação , Metabolismo dos Lipídeos , Vinho/microbiologia , Leveduras/metabolismo , Compostos Orgânicos Voláteis/metabolismo , Leveduras/crescimento & desenvolvimento
19.
Hum Mutat ; 40(9): 1463-1473, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31283071

RESUMO

This paper reports the evaluation of predictions for the "CALM1" challenge in the fifth round of the Critical Assessment of Genome Interpretation held in 2018. In the challenge, the participants were asked to predict effects on yeast growth caused by missense variants of human calmodulin, a highly conserved protein in eukaryotic cells sensing calcium concentration. The performance of predictors implementing different algorithms and methods is similar. Most predictors are able to identify the deleterious or tolerated variants with modest accuracy, with a baseline predictor based purely on sequence conservation slightly outperforming the submitted predictions. Nevertheless, we think that the accuracy of predictions remains far from satisfactory, and the field awaits substantial improvements. The most poorly predicted variants in this round surround functional CALM1 sites that bind calcium or peptide, which suggests that better incorporation of structural analysis may help improve predictions.


Assuntos
Calmodulina/química , Calmodulina/genética , Biologia Computacional/métodos , Mutação de Sentido Incorreto , Leveduras/crescimento & desenvolvimento , Algoritmos , Sítios de Ligação , Cálcio/metabolismo , Calmodulina/metabolismo , Evolução Molecular , Proteínas Fúngicas/química , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Aptidão Genética , Humanos , Modelos Genéticos , Modelos Moleculares , Conformação Proteica , Engenharia de Proteínas , Leveduras/genética
20.
Biotechnol Lett ; 41(8-9): 1067-1076, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31300936

RESUMO

OBJECTIVES: Establish a method to restrict unexpected fragments including stop codons in scFv library and generate a thermo resistant strain for screening of thermal stable scFv sequences. RESULTS: Here, we have constructed a T2A-Leu2 system for selection of yeast surface display libraries that blocks amplification of "stop codon" plasmids within the library, thereby increasing the quality of the library and efficiency of the selection screen. Also, we generated a temperature-resistant yeast strain, TR1, and validated its combined use with T2A-Leu2 for efficient screening. Thus, we developed a general approach for a fast and efficient screening of scFv libraries using a ribosomal skipping system and thermo-resistant yeast. CONCLUSIONS: The method highlights the utility of the T2A-Leu2-based ribosomal skipping strategy for increasing the quality of the input library for selection, along with an optimized selection protocol based on thermo-resistant yeast cells.


Assuntos
Técnicas de Visualização da Superfície Celular/métodos , Biblioteca Gênica , Anticorpos de Cadeia Única/biossíntese , Leveduras/genética , Leveduras/metabolismo , Testes Genéticos/métodos , Temperatura Alta , Engenharia Metabólica/métodos , Estabilidade Proteica/efeitos da radiação , Anticorpos de Cadeia Única/genética , Leveduras/crescimento & desenvolvimento , Leveduras/efeitos da radiação
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