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1.
J Sci Food Agric ; 100(3): 1164-1173, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31680258

RESUMO

BACKGROUND: This study was conducted to analyze the effects of endophytic Bacillus megaterium (BM 18-2) colonization on structure strengthening, microbial community, chemical composition and stabilization properties of Hybrid Pennisetum. RESULTS: The BM 18-2 had successfully colonized in the interior tissues in both leaf and stem of Hybrid Pennisetum. During ensiling, the levels of pH, acetic acid (AA), butyric acid (BA), propionic acid (PA), and the population of yeast and aerobic bacteria were significantly (P > 0.05) lower, while lactic acid bacteria (LAB) and lactic acid (LA) were significantly (P < 0.001) higher with the steps forward of ensiling in with BM 18-2 as compared to without BM 18-2 colonized of Hybrid Pennisetum. During the different ensiling days, at days 3, 6, 15, and 30, the genus Brevundimonas, Klebsiella, Lactococcus, Weissella, Enterobacter, Serratia, etc. population were significantly decreased, while genus Pediococcus acidilactici and Lactobacillus plantarum were significantly influenced in treated groups as compared to control. The genus Lactobacillus and Pediococcus were positively correlated with treatment groups. CONCLUSIONS: It is concluded that the endophytic bacteria strain BM 18-2 significantly promoted growth characteristics and biomass yield before ensiling and after ensiling inoculated with or without Lactobacillus plantarum could improve the distinct changes of the undesirable microbial diversity, chemical composition, and stabilization properties in with BM 18-2 as compared to without BM 18-2 colonized Hybrid Pennisetum. © 2019 Society of Chemical Industry.


Assuntos
Bacillus megaterium/crescimento & desenvolvimento , Endófitos/crescimento & desenvolvimento , Microbiota , Pennisetum/microbiologia , Ácido Acético/metabolismo , Bacillus megaterium/genética , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , Bactérias/metabolismo , Ácido Butírico/metabolismo , Endófitos/genética , Ácido Láctico/metabolismo , Pennisetum/genética , Pennisetum/crescimento & desenvolvimento , Leveduras/classificação , Leveduras/genética , Leveduras/isolamento & purificação , Leveduras/metabolismo
2.
Lett Appl Microbiol ; 70(1): 48-54, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31642537

RESUMO

This study aims to describe the native microbiota of fermented spelt, taking into consideration both lactic acid bacteria (LAB) and yeasts, for which little data are available. Five samples of commercial spelt flour were subjected to spontaneous fermentation to obtain a type I sourdough. A total of 186 LAB and 174 yeast isolates were selected at different refreshment steps and subjected to further analyses. Within LAB, coccal isolates constituted 78·5% of the total LAB, with the dominance of Pediococcus pentosaceus. Although documented before as a component, this is the first report of a spelt sourdough fermentation dominated by this homofermentative LAB, characterized by a high acidification rate, ability to utilize a wide range of carbon sources and to grow in high osmolarity conditions. Yeast communities resulted in four dominant species, Saccharomyces cerevisiae, Wickerhamomyces anomalus, Pichia fermentans and Clavispora lusitaniae. This study highlights for the first time the biodiversity and dynamics of yeast communities involved in sourdough fermentation of spelt. Compared to commercial baker's yeast, autochthonous W. anomalus, P. fermentans and S. cerevisiae isolates show a good performance, and their use could be an advantage for their acquired adaptation to the environment, providing stability to the fermentation process. SIGNIFICANCE AND IMPACT OF THE STUDY: Nowadays, there is a renewed interest in products based on spelt. This 'ancient grain' is a highly nutritional grain; however, its use is limited to bread-making processes, which are not standardized. The low baking and sensory quality of spelt can be overcome through fermentation processes. However, the autochthonous microbiota of spelt sourdough is poorly known. This study highlights the dynamics of microbial communities involved in sourdough fermentation of spelt and provides the basis for the selection of autochthonous cultures, with the aim of improving the nutritional potential of spelt and its rheology and bread-making properties.


Assuntos
Pão/microbiologia , Lactobacillales/metabolismo , Consórcios Microbianos , Triticum/microbiologia , Leveduras/metabolismo , Biodiversidade , Pão/análise , Fermentação , Farinha/microbiologia , Microbiologia de Alimentos , Lactobacillales/classificação , Lactobacillales/genética , Lactobacillales/isolamento & purificação , Triticum/metabolismo , Leveduras/classificação , Leveduras/genética , Leveduras/isolamento & purificação
3.
An Acad Bras Cienc ; 91(4): e20190052, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31800704

RESUMO

The biotechnological potential of yeasts associated to different habitats in Colombia has been poorly studied, especially the yeasts associated with different plant structures. Fruit pulps are interesting substrates mainly for the growth of yeast species, that can positively affect the productivity and quality of some bioeconomic species. Therefore, the objective of this study was to identify the dominant yeast species associated with mango and rose apple fruit pulps in Cali, Colombia. A total of 90 isolates were obtained, which were grouped considering their colony morphology. The D1/D2 domain of the large ribosomal RNA gene (LSU rRNA gene) or internal transcribed spacer (ITS) 1, ribosomal gene 5.8S and ITS 2 (ITS) regions of one to several representative isolates from each group was sequenced and compared with type strains for identification. The species Hanseniaspora thailandica, H. opuntiae and Clavispora lusitaniae were reported as shared by both fruits, specific for rose apple (H. uvarum, Pichia terricola, Rhodosporidiobolus ruineniae and Candida albicans), or for Mango (Meyerozyma caribbica, M. guilliermondii, C. natalensis, Aureobasidium pullulans, Pichia sp., Saturnispora diversa and C. jaroonii). Two morphotypes were not identified at the taxonomic level of species and were reported as candidates for new species, belonging to the genera Wickerhamomyces and Pichia.


Assuntos
DNA Fúngico/genética , Frutas/microbiologia , Mangifera/microbiologia , Syzygium/microbiologia , Leveduras/genética , Colômbia , Reação em Cadeia da Polimerase , Leveduras/classificação , Leveduras/isolamento & purificação
4.
World J Microbiol Biotechnol ; 35(10): 154, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31576429

RESUMO

Yeasts occur in all environments and have been described as potent antagonists of various plant pathogens. Due to their antagonistic ability, undemanding cultivation requirements, and limited biosafety concerns, many of these unicellular fungi have been considered for biocontrol applications. Here, we review the fundamental research on the mechanisms (e.g., competition, enzyme secretion, toxin production, volatiles, mycoparasitism, induction of resistance) by which biocontrol yeasts exert their activity as plant protection agents. In a second part, we focus on five yeast species (Candida oleophila, Aureobasidium pullulans, Metschnikowia fructicola, Cryptococcus albidus, Saccharomyces cerevisiae) that are or have been registered for the application as biocontrol products. These examples demonstrate the potential of yeasts for commercial biocontrol usage, but this review also highlights the scarcity of fundamental studies on yeast biocontrol mechanisms and of registered yeast-based biocontrol products. Yeast biocontrol mechanisms thus represent a largely unexplored field of research and plentiful opportunities for the development of commercial, yeast-based applications for plant protection exist.


Assuntos
Agentes de Controle Biológico/farmacologia , Doenças das Plantas/prevenção & controle , Leveduras/química , Agentes de Controle Biológico/química , Agentes de Controle Biológico/metabolismo , Doenças das Plantas/microbiologia , Leveduras/classificação , Leveduras/genética , Leveduras/metabolismo
5.
Int J Mol Sci ; 20(19)2019 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-31569563

RESUMO

Both the presence of, and the important contribution to growth and development made by TCP transcription factors, have been established in various plant species. Here, a TCP4 homolog isolated from Chrysanthemum nankingense was shown to be more strongly transcribed in the diploid than in the autotetraploid form of the species. CnTCP4 was shown to encode a member of the class II TCP family and to be transcribed most strongly in the leaf and ligulate flowers. Its transcription was found to be substantially inhibited by spraying the plant with the synthetic cytokinin 6-benzylaminopurine. The transient expression of CnTCP4 in onion epidermal cells showed that its product localized to the nucleus, and a yeast one hybrid assay suggested that its product had transcriptional activation ability. The constitutive expression of CnTCP4 in fission yeast suppressed cell proliferation, inducing the formation of longer and a higher frequency of multinuclated cells. Its constitutive expression in Arabidopsis thaliana reduced the size of the leaves. The presence of the transgene altered the transcription of a number of cell division-related genes. A yeast one hybrid assay identified a second TCP gene (CnTCP2) able to interact with the CnTCP4 promoter. A transient expression experiment in Nicotiana benthamiana leaves showed that CnTCP2 was able to activate the CnTCP4 promoter. Like CnTCP4, CnTCP2 was shown to encode a member of the class II TCP family, to be transcribed most strongly in the leaf and ligulate flowers, and to be suppressed by exogenous 6-benzylaminopurine treatment. The CnTCP2 protein also localized to the nucleus, but had no transcriptional activation ability. Its constitutive expression in A. thaliana had similar phenotypic consequences to those induced by CnTCP4.


Assuntos
Arabidopsis/genética , Divisão Celular/genética , Chrysanthemum/genética , Expressão Gênica , Fatores de Transcrição/genética , Leveduras/genética , Sequência de Aminoácidos , Arabidopsis/classificação , Arabidopsis/metabolismo , Perfilação da Expressão Gênica , Fenótipo , Filogenia , Regiões Promotoras Genéticas , Transcriptoma , Leveduras/classificação , Leveduras/metabolismo
6.
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
7.
BMC Biotechnol ; 19(1): 58, 2019 08 05.
Artigo em Inglês | MEDLINE | ID: mdl-31382948

RESUMO

BACKGROUND: Efficient xylose fermentation still demands knowledge regarding xylose catabolism. In this study, metabolic flux analysis (MFA) and metabolomics were used to improve our understanding of xylose metabolism. Thus, a stoichiometric model was constructed to simulate the intracellular carbon flux and used to validate the metabolome data collected within xylose catabolic pathways of non-Saccharomyces xylose utilizing yeasts. RESULTS: A metabolic flux model was constructed using xylose fermentation data from yeasts Scheffersomyces stipitis, Spathaspora arborariae, and Spathaspora passalidarum. In total, 39 intracellular metabolic reactions rates were utilized validating the measurements of 11 intracellular metabolites, acquired by mass spectrometry. Among them, 80% of total metabolites were confirmed with a correlation above 90% when compared to the stoichiometric model. Among the intracellular metabolites, fructose-6-phosphate, glucose-6-phosphate, ribulose-5-phosphate, and malate are validated in the three studied yeasts. However, the metabolites phosphoenolpyruvate and pyruvate could not be confirmed in any yeast. Finally, the three yeasts had the metabolic fluxes from xylose to ethanol compared. Xylose catabolism occurs at twice-higher flux rates in S. stipitis than S. passalidarum and S. arborariae. Besides, S. passalidarum present 1.5 times high flux rate in the xylose reductase reaction NADH-dependent than other two yeasts. CONCLUSIONS: This study demonstrated a novel strategy for metabolome data validation and brought insights about naturally xylose-fermenting yeasts. S. stipitis and S. passalidarum showed respectively three and twice higher flux rates of XR with NADH cofactor, reducing the xylitol production when compared to S. arborariae. Besides then, the higher flux rates directed to pentose phosphate pathway (PPP) and glycolysis pathways resulted in better ethanol production in S. stipitis and S. passalidarum when compared to S. arborariae.


Assuntos
Fermentação , Análise do Fluxo Metabólico/métodos , Metaboloma , Metabolômica/métodos , Saccharomycetales/metabolismo , Frutosefosfatos/metabolismo , Glucose-6-Fosfato/metabolismo , Glicólise , Malatos/metabolismo , Espectrometria de Massas/métodos , Modelos Biológicos , Via de Pentose Fosfato , Ribulosefosfatos/metabolismo , Saccharomycetales/classificação , Leveduras/classificação , Leveduras/metabolismo
8.
Int J Syst Evol Microbiol ; 69(11): 3385-3391, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31368884

RESUMO

During a survey of yeast populations associated with grape and apple musts used for wine and cider fermentation, respectively, six pink-coloured ballistoconidia-forming yeasts belonging to the order Sporidiobolales (Basidiomycota) were isolated. Phylogenetic analysis inferred using sequences of the internal transcribed spacer (ITS), the D1/D2 domain of the large subunit rRNA gene, the small subunit (SSU) rRNA gene and DNA-directed RNA polymerase II subunit (RPB2) indicated that the six isolates were separated in two novel species. One of the new species, Sporobolomyces agrorum sp. nov., isolated from grape must, had Sporobolomyces roseus and Sporobolomyces metaroseus as its closest relatives, but showed four/two and 16 nucleotide substitutions in the D1/D2 and ITS regions, respectively, to these two species. The other novel species, Sporobolomyces sucorum sp. nov., was found in apple must and was closely related to Sporobolomyces pararoseus and Sporobolomyces patagonicus, but showed two/three and five substitutions in those two regions for its closest relatives. We detected additional representatives of this species, most of them isolated from grapes whose sequences were already available on public databases. A sexual stage could not be observed for the novel species.


Assuntos
Basidiomycota/classificação , Malus/microbiologia , Filogenia , Vitis/microbiologia , Basidiomycota/isolamento & purificação , DNA Fúngico/genética , DNA Espaçador Ribossômico/genética , Itália , Técnicas de Tipagem Micológica , Análise de Sequência de DNA , Esporos Fúngicos , Leveduras/classificação , Leveduras/isolamento & purificação
9.
World J Microbiol Biotechnol ; 35(7): 108, 2019 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-31267227

RESUMO

A total of 191 yeasts were isolated from 197 samples collected from eight estuarine mangrove forests along four different coastlines of Thailand (Andaman Sea and the East, North and West coasts of the Gulf of Thailand). Of these, 178 isolates were identified as 32 species in 16 genera of Ascomycota, 12 species in nine genera of Basidiomycota, and 13 isolates as potential new species, respectively. Mangroves located along the Andaman Sea coastline had a higher yeast diversity at the species and genera levels than those along the Gulf of Thailand. Kluyveromyces siamensis was the most frequently isolated species, whilst Candida tropicalis was the only species isolated at all eight sites. Screening isolated yeast strains belonging to genera previously reported as oleaginous yeast plus the 13 potential new species, revealed two oleaginous strains, Rhodotorula sphaerocarpa 11-14.4 and Saitozyma podzolica 11-11.3.1. Both of these strains were isolated from the same mangrove forest on the Andaman Sea coastline. They could accumulate lipid when suspended in glucose solution without any supplementation, while the fatty acid composition and oil profile of Rh. sphaerocarpa 11-14.4 and Sait. podzolica 11-11.3.1 were similar to vegetable oil and cocoa butter, respectively.


Assuntos
Filogenia , Áreas Alagadas , Leveduras/classificação , Leveduras/isolamento & purificação , Ascomicetos/química , Ascomicetos/classificação , Ascomicetos/isolamento & purificação , Basidiomycota/química , Basidiomycota/classificação , Basidiomycota/isolamento & purificação , Biodiversidade , Biocombustíveis , DNA Fúngico/análise , DNA Fúngico/isolamento & purificação , Gorduras na Dieta , Ácidos Graxos/análise , Glucose/metabolismo , Metabolismo dos Lipídeos , Lipídeos/análise , Tipagem Molecular , Óleos Vegetais , RNA Ribossômico/genética , Análise de Sequência , Tailândia , Leveduras/química , Leveduras/genética
10.
J Appl Microbiol ; 127(4): 1080-1100, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31286622

RESUMO

AIMS: To assess the ability of various newly isolated or belonging in official collections yeast strains to convert biodiesel-derived glycerol (Gly) into added-value compounds. METHODS AND RESULTS: Ten newly isolated yeast strains belonging to Debaryomyces sp., Naganishia uzbekistanensis, Rhodotorula sp. and Yarrowia lipolytica, isolated from fishes, metabolized Gly under nitrogen limitation. The aim of the study was to identify potential newly isolated microbial candidates that could produce single-cell oil (SCO), endopolysaccharides and polyols when these micro-organisms were grown on biodiesel-derived Gly. As controls producing SCO and endopolysaccharides were the strains Rhodotorula glutinis NRRL YB-252 and Cryptococcus curvatus NRRL Y-1511. At initial Gly (Gly0 ) ≈40 g l-1 , most strains presented remarkable dry cell weight (DCW) production, whereas Y. lipolytica and Debaryomyces sp. produced non-negligible quantities of mannitol and arabitol (Ara). Five strains were further cultivated at increasing Gly0 concentrations. Rhodotorula glutinis NRRL YB-252 produced 7·2 g l-1 of lipid (lipid in DCW value ≈38% w/w), whereas Debaryomyces sp. FMCC Y69 in batch-bioreactor experiment with Gly0 ≈80 g l-1 , produced 30-33 g l-1 of DCW and ~30 g l-1 of Ara. At shake-flasks with Gly0 ≈125 g l-1 , Ara of ~48 g l-1 (conversion yield of polyol on Gly consumed ≈0·62 g g-1 ) was achieved. Cellular lipids of all yeasts contained in variable concentrations oleic, palmitic, stearic and linoleic acids. CONCLUSIONS: Newly isolated, food-derived and non-previously studied yeast isolates converted biodiesel-derived Gly into several added-value metabolites. SIGNIFICANCE AND IMPACT OF THE STUDY: Alternative ways of crude Gly valorization through yeast fermentations were provided and added-value compounds were synthesized.


Assuntos
Biocombustíveis/microbiologia , Glicerol , Leveduras , Polissacarídeos Fúngicos/análise , Polissacarídeos Fúngicos/metabolismo , Glicerol/análise , Glicerol/metabolismo , Lipídeos/análise , Polímeros/análise , Polímeros/metabolismo , Leveduras/classificação , Leveduras/metabolismo
11.
Food Sci Technol Int ; 25(8): 671-679, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31272221

RESUMO

Spoilage caused by yeasts is a constant, widespread problem in the beverage industry that can result in major economic losses. Fruit juices provide an environment that allows the proliferation of yeast. Some factories in South Africa are not equipped with laboratory facilities to identify spoilage yeasts and outsourcing becomes a prolonged process which obstructs corrective action planning. This study aimed to establish yeast diversity and apply a rapid method for preliminary identification of spoilage yeasts associated with a small-scale fruit juice bottling factory. Yeast population in the factory was determined by isolation from the production environment, process equipment and spoiled products. PCR-RFLP analysis targeting the 5.8S-ITS region and D1/D2 sequencing was used for identification. A total of 207 yeasts belonging to 10 different genera (Candida, Lodderomyces, Wickerhamomyces, Yarrowia, Zygosaccharomyces, Zygoascus, Cryptococcus, Filobasidium, Rhodotorula/Cystobasidium and Trichosporon) were isolated and identified from the production environment and processing equipment. Candida intermedia, C. parapsilosis and Lodderomyces elongisporus were widely distributed in the factory. Zygosaccharomyces bailii, Z. bisporus, Zygoascus hellenicus and Saccharomyces cerevisiae were isolated from the spoiled products. The data provided a yeast control panel that was used successfully to identify unknown yeasts in spoiled products from this factory using polymerase chain reaction-restriction length polymorphism (PCR-RFLP) comparative analysis.


Assuntos
Contaminação de Alimentos/análise , Sucos de Frutas e Vegetais/microbiologia , Reação em Cadeia da Polimerase/métodos , Polimorfismo de Fragmento de Restrição , Leveduras/classificação , Leveduras/isolamento & purificação , Biodiversidade , DNA Fúngico , Manipulação de Alimentos , Técnicas de Tipagem Micológica , RNA Ribossômico/análise , RNA Ribossômico/genética , RNA Ribossômico 5,8S/análise , RNA Ribossômico 5,8S/genética , Análise de Sequência , Leveduras/genética , Leveduras/crescimento & desenvolvimento
12.
PLoS One ; 14(6): e0217385, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31220090

RESUMO

Yeast species that colonize the surface of grape berries at harvest time play an important role during the winemaking process. In this study, the use of culturable microbial techniques permitted a quantitative and qualitative inventory of the different yeast species present on the grape berry surfaces of Montepulciano and Verdicchio varieties when treated with conventional and organic fungicides. The results show that the most widespread yeast species at harvest time were Aureobasidium pullulans and Hanseniaspora uvarum, which are considered normal resident species and independent of the grape varieties and treatments applied. Specific differences when comparing the grape varieties were observed in species and were detected at a lower frequency; Pichia spp. were prevalent in Verdicchio, whereas Lachancea thermotolerans and Zygoascus meyerae were found in Montepulciano. In both vineyards, the farming treatments improved the competitiveness of A. pullulans, which was probably due to its reduced susceptibility to treatments that improved the competition toward other fungi. In contrast, the fermenting yeast H. uvarum was negatively affected by fungicide treatments and showed a reduced presence if compared with untreated grapes. Organic treatments directly impacted the occurrence of Issachenkia terricola in Montepulciano grapes and Debaryomyces hansenii and Pichia membranifaciens in Verdicchio. Conversely, a negative effect of organic treatments was found toward Metschnikowia pulcherrima and Starmerella bacillaris. Overall, the data suggest that the yeast community colonizing the grape berry surface was influenced by both grape variety and farming treatments, which characterized the yeast biota of spontaneous must fermentation.


Assuntos
Microbiota , Vitis/microbiologia , Leveduras , Fazendas , Leveduras/classificação , Leveduras/crescimento & desenvolvimento , Leveduras/isolamento & purificação
13.
J Appl Microbiol ; 127(3): 845-855, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31211890

RESUMO

AIMS: The aim was to isolate, identify and characterize yeasts present in rumen fluid and to select strains showing potential as probiotics. METHODS AND RESULTS: Rumen fluid was sampled from 4 herds of dairy and beef cattle and 77 yeast isolates were identified. Initial screening was based on the capacity to maintain viability in a medium with different ruminal conditions. A second screening in fresh rumen fluid to assess the growth of inoculated yeasts and evaluate in vitro neutral detergent fibre digestibility (NDF-D), pH and acid accumulation was conducted. The yeast population ranged from 3·84 to 6·76 log10 CFU per ml. The main species of yeast found were Pichia kudriavzevii, Candida rugosa, C. pararugosa, C. ethanolica and Magnusiomyces capitatus. Strains CCMA 933 (C. rugosa) and CCMA 970 (C. pararugosa) showed greater ability to survive in ruminal fluid and stimulated the production of acids. Isolate CCMA 967 (C. ethanolica) survived and improved the NDF-D. CONCLUSION: Pichia kudriavzevii was the dominant yeast found in the cattle herds. Strains CCMA 933, CCMA 970 and CCMA 967 showed properties that could be useful as potential probiotics for cattle. SIGNIFICANCE AND IMPACT OF THE STUDY: This study was the first to select yeasts from the rumen fluid, with the potential to be used as probiotic, based on the ruminal conditions.


Assuntos
Probióticos/isolamento & purificação , Rúmen/microbiologia , Leveduras/classificação , Ração Animal , Animais , Bovinos , Feminino , Fermentação , Rúmen/metabolismo , Leveduras/isolamento & purificação , Leveduras/fisiologia
14.
Arch Microbiol ; 201(8): 1147-1149, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31147748

RESUMO

Non-albicans Candida species have acquired relevance in the last decades as a cause of serious disease. The virulence factors and antifungal susceptibility of these rare pathogens remain largely unrecognized. We examined a total of 50 yeast isolates corresponding to 11 different infrequently isolated yeast species for their in vitro enzymatic profile and susceptibility pattern as first-line antifungals. We found aspartyl protease activity for 100% of the isolates tested as well as variable DNAse, hemolysin, phospholipase and esterase activities. All strains had low MICs for amphotericin B and showed a variable response to fluconazole (0.125-32 µg/mL) and the echinocandins tested (0.25-> 8 µg/mL).


Assuntos
Anfotericina B/farmacologia , Antifúngicos/farmacologia , Candida/efeitos dos fármacos , Candida/genética , Equinocandinas/farmacologia , Fluconazol/farmacologia , Ácido Aspártico Proteases/genética , Candida/classificação , Candida/isolamento & purificação , Desoxirribonucleases/genética , Esterases/genética , Proteínas Hemolisinas/genética , Humanos , Testes de Sensibilidade Microbiana , Fosfolipases/genética , Fatores de Virulência , Leveduras/classificação , Leveduras/efeitos dos fármacos , Leveduras/isolamento & purificação
15.
BMC Microbiol ; 19(1): 100, 2019 05 17.
Artigo em Inglês | MEDLINE | ID: mdl-31101012

RESUMO

BACKGROUND: Thermotolerance is a highly desirable trait of microbial cell factories and has been the focus of extensive research. Yeast usually tolerate only a narrow temperature range and just two species, Kluyveromyces marxianus and Ogataea polymorpha have been described to grow at reasonable rates above 40 °C. However, the complex mechanisms of thermotolerance in yeast impede its full comprehension and the rare physiological data at elevated temperatures has so far not been matched with corresponding metabolic analyses. RESULTS: To elaborate on the metabolic network response to increased fermentation temperatures of up to 49 °C, comprehensive physiological datasets of several Kluyveromyces and Ogataea strains were generated and used for 13C-metabolic flux analyses. While the maximum growth temperature was very similar in all investigated strains, the metabolic network response to elevated temperatures was not conserved among the different species. In fact, metabolic flux distributions were remarkably irresponsive to increasing temperatures in O. polymorpha, while the K. marxianus strains exhibited extensive flux rerouting at elevated temperatures. CONCLUSIONS: While a clear mechanism of thermotolerance is not deducible from the fluxome level alone, the generated data can be valued as a knowledge repository for using temperature to modulate the metabolic activity towards engineering goals.


Assuntos
Temperatura Alta , Redes e Vias Metabólicas , Termotolerância , Leveduras/fisiologia , Fermentação , Kluyveromyces/fisiologia , Pichia/fisiologia , Saccharomyces cerevisiae/fisiologia , Leveduras/classificação
16.
Curr Microbiol ; 76(7): 909-916, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31119361

RESUMO

The aim of the present study was to assess the transcription of the plnE/F, plnN, plnG, plnD and plnI genes during lactic acid fermentation of radish (Raphanus sativus) roots by Lactobacillus plantarum strain LQC 740 at 20 and 30 °C. At both temperatures, this strain dominated the fermentation process, as indicated by (GTG)5 analysis. A total of five pln genes were detected in the genome of this strain, namely plnE/F, plnN, plnG, plnD and plnI. Regarding plantaricin genes expression, no regulation was observed in the majority of the samples at both temperatures, therefore, the transcription of the pln genes was not affected by the experimental conditions, i.e. radish fermentation vs. growth in MRS broth. Although transcription of the pln genes was similar between the two conditions, bacteriocin activity was different. The maximum plantaricin activity was 87.5 AU/mL during radish fermentation and 700 AU/mL during growth in MRS broth. Thus, no apparent correlation between bacteriocin activity and transcription level of the five pln genes could be established.


Assuntos
Bacteriocinas/genética , Regulação da Expressão Gênica , Lactobacillus plantarum/metabolismo , Raphanus/microbiologia , Bactérias/classificação , Bactérias/genética , Bactérias/crescimento & desenvolvimento , Bactérias/isolamento & purificação , Bacteriocinas/metabolismo , Fermentação , Concentração de Íons de Hidrogênio , Lactobacillus plantarum/genética , Lactobacillus plantarum/crescimento & desenvolvimento , Microbiota/genética , Raízes de Plantas/metabolismo , Raízes de Plantas/microbiologia , Raphanus/metabolismo , Leveduras/classificação , Leveduras/genética , Leveduras/crescimento & desenvolvimento , Leveduras/isolamento & purificação
17.
Database (Oxford) ; 20192019 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-31032841

RESUMO

The transcription initiation landscape of eukaryotic genes is complex and highly dynamic. In eukaryotes, genes can generate multiple transcript variants that differ in 5' boundaries due to usages of alternative transcription start sites (TSSs), and the abundance of transcript isoforms are highly variable. Due to a large number and complexity of the TSSs, it is not feasible to depict details of transcript initiation landscape of all genes using text-format genome annotation files. Therefore, it is necessary to provide data visualization of TSSs to represent quantitative TSS maps and the core promoters (CPs). In addition, the selection and activity of TSSs are influenced by various factors, such as transcription factors, chromatin remodeling and histone modifications. Thus, integration and visualization of functional genomic data related to these features could provide a better understanding of the gene promoter architecture and regulatory mechanism of transcription initiation. Yeast species play important roles for the research and human society, yet no database provides visualization and integration of functional genomic data in yeast. Here, we generated quantitative TSS maps for 12 important yeast species, inferred their CPs and built a public database, YeasTSS (www.yeastss.org). YeasTSS was designed as a central portal for visualization and integration of the TSS maps, CPs and functional genomic data related to transcription initiation in yeast. YeasTSS is expected to benefit the research community and public education for improving genome annotation, studies of promoter structure, regulated control of transcription initiation and inferring gene regulatory network.


Assuntos
Bases de Dados de Ácidos Nucleicos , Internet , Sítio de Iniciação de Transcrição , Leveduras/genética , Leveduras/classificação
18.
Spectrochim Acta A Mol Biomol Spectrosc ; 218: 299-307, 2019 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-31005737

RESUMO

The molecular fingerprints of yeasts Saccharomyces cerevisiae, Dekkera bruxellensis, and Wickerhamomyces anomalus (former name Pichia anomala) have been examined using surface-enhanced Raman spectroscopy (SERS) and helium ion microscopy (HIM). The SERS spectra obtained from cell cultures (lysate and non-treated cells) distinguish between these very closely related fungal species. Highly SERS active silver nano-particles suitable for detecting complex biomolecules were fabricated using a simple synthesis route. The yeast samples mixed with aggregated Ag nanoparticles yielded highly enhanced and reproducible Raman signal owing to the high density of the hot spots at the junctions of two or more Ag nanoparticles and enabled to differentiate the three species based on their unique features (spectral fingerprint). We also collected SERS spectra of the three yeast species in beer medium to demonstrate the potential of the method for industrial application. These findings demonstrate the great potential of SERS for detection and identification of fungi species based on the biochemical compositions, even in a chemically complex sample.


Assuntos
Técnicas de Tipagem Micológica/métodos , Análise Espectral Raman/métodos , Leveduras/química , Dekkera/química , Dekkera/classificação , Dekkera/isolamento & purificação , Nanopartículas Metálicas/química , Nanopartículas Metálicas/ultraestrutura , Pichia/química , Pichia/classificação , Pichia/isolamento & purificação , Saccharomyces cerevisiae/química , Saccharomyces cerevisiae/classificação , Saccharomyces cerevisiae/isolamento & purificação , Prata/química , Propriedades de Superfície , Leveduras/classificação , Leveduras/isolamento & purificação
19.
Food Microbiol ; 82: 259-268, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31027782

RESUMO

The aim of this study is to examine the biogeography of the microbial communities associated to the Spanish-style green olive fermentations in the province of Seville (Andalucía, south-western Spain). Also, to understand how microorganisms colonize and persist in non-sterile food fermentations across a specific table olive producing area, i.e. a specific "agroecosystem". The microbial diversity, bacteria and yeast, in 30 ten-ton fermenters of three different fermentations yards (patios) along the olive fermentation was studied. A total of 951 microbial isolates were obtained which were clustered according to their RAPD profile. A total of 376 distinct genotypes were identified, belonging to 57 different microbial species, 41 bacterial and 16 yeast species. Up to 16 bacterial species had not been described before in table olives. Only the species Lactobacillus pentosus showed a ubiquitous presence in all 30 fermenters. Pediococcus parvulus, Lactobacillus collinoides/paracollinoides, Lactobacillus coryniformis, Lactobacillus plantarum, Pichia manshurica and Candida thaimueangensis were found in every patio. Cosmopolitan strains, up to 15, were shared by the three patios and belonged to the species L. pentosus (12 strains), P. parvulus (1), L. collinoides/paracollinoides (1) and P. manshurica (1). To expand our biodiversity analyses to the "regional" level, we have compared our results with those obtained from two previously studied patios of similar characteristics and in the same geographical area. PERMANOVA analysis of the microbial community composition revealed significant differences among different patios in their structure at every fermentation stage. In contrast, SIMPER analyses showed that, as fermentation progressed, the overall dissimilarities among patios were reduced. Discriminant species were identified for each fermentation stage. Among these, L. pentosus and P. parvulus were "eu-constant" species, while L. collinides/paracollinoides and Marinilactibacillus psychrotolerans group were "constant" species that could be considered microbial key taxa based on the occurrence stability index. The characteristic and, presumably, well adapted microbiota associated to the Spanish-style olive fermentations at the specific geographic area described here is a valuable natural resource which should be preserved conveniently. To our knowledge, this is the first study on the microbial biogeography of table olive fermentations, both at the species and strain levels.


Assuntos
Bactérias/isolamento & purificação , Biodiversidade , Reatores Biológicos/microbiologia , Olea/microbiologia , Leveduras/isolamento & purificação , Bactérias/classificação , Bactérias/genética , Bactérias/crescimento & desenvolvimento , Ecossistema , Fermentação , Microbiologia de Alimentos , Variação Genética , Concentração de Íons de Hidrogênio , Lactobacillus/classificação , Lactobacillus/genética , Lactobacillus/crescimento & desenvolvimento , Lactobacillus/isolamento & purificação , Microbiota/genética , Sais , Espanha , Leveduras/classificação , Leveduras/genética , Leveduras/crescimento & desenvolvimento
20.
Arch Microbiol ; 201(3): 399-407, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30719527

RESUMO

During this study, we characterized the seasonality's impact and environmental conditions on the yeast diversity from raw camel's milk collected in Algeria. The yeast counts were estimated to 3.55 × 102 CFU mL-1, with a maximum of 6.3 × 102 CFU mL-1. The yeasts were categorized phenotypically by API 20C AUX, MALDI-TOF and genetically by sequencing 26S rDNA and ITS1-5.8S-ITS2. The rDNA sequencing approaches revealed 12 species including unusual ones such as Trichosporon asahii, Pichia fermentans, Millerozyma farinosa, Pichia galeiformis, Candida tartarivorans and Pichia manshurica. The most dominant species were T. asahii (23%), P. fermentans (19%) and Rhodotorula mucilaginosa (14%). The high occurrence and large diversity were registered in samples collected during the autumn season, in the semi-arid and arid highlands regions with 0.66 × 103 CFU mL-1 and 0.51 × 103 CFU mL-1, respectively. Interestingly, T. asahii, R. mucilaginosa, P. fermentans, C. parapsilosis and C. zeylanoides were detected during both spring and autumn.


Assuntos
Camelus/microbiologia , Candida/isolamento & purificação , Leite/microbiologia , Pichia/isolamento & purificação , Rhodotorula/isolamento & purificação , Saccharomyces cerevisiae/isolamento & purificação , Leveduras/isolamento & purificação , Argélia , Animais , Candida/classificação , Candida/genética , DNA Fúngico/genética , DNA Ribossômico/genética , Pichia/classificação , Pichia/genética , Rhodotorula/classificação , Rhodotorula/genética , Saccharomyces cerevisiae/classificação , Saccharomyces cerevisiae/genética , Estações do Ano , Leveduras/classificação , Leveduras/genética
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