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1.
Bioresour Technol ; 315: 123893, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32736320

RESUMO

Consolidated bioprocesses for bioconversion of lignocellulosic biomass into biodiesel feedstocks were developed. Palm empty fruit bunch (EFB) was biologically pretreated coupling with fungal lipid production (121.4 ± 2.7 mg/g-EFB) by lignocellulolytic oleaginous fungi prior to lipid production by oleaginous yeasts. In subsequent separate hydrolysis and fermentation (SHF) of fungal pretreated EFB (FPEFB), the oleaginous yeast with the maximum lipid yield of 37.0 ± 0.1 mg/g-FPEFB was screened. While a higher lipid yield of 47.9 ± 1.5 mg/g-FPEFB was achieved in simultaneous saccharification and fermentation (SSF) with less enzyme requirement. Fed-batch SSF of non-sterile FPEFB was proven as a practical and efficient strategy to increase lipid yield up to 53.4 ± 0.5 mg/g-FPEFB. Total lipid yield by both fungi and yeast was 165.0 ± 4.4 mg/g-EFB. Interestingly, the consolidated bioprocesses of enzyme and lipid production also achieved comparable total lipid yield of 149.3 ± 6.6 mg/g-EFB. These strategies may contribute greatly to cost-effective and sustainable bioconversion of lignocellulosic biomass into biodiesel feedstocks.


Assuntos
Biocombustíveis , Leveduras , Biomassa , Fermentação , Fungos
2.
PLoS Negl Trop Dis ; 14(7): e0008447, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32730343

RESUMO

Only a single drug against schistosomiasis is currently available and new drug development is urgently required but very few drug targets have been validated and characterised. However, regulatory systems including cyclic nucleotide metabolism are emerging as primary candidates for drug discovery. Here, we report the cloning of ten cyclic nucleotide phosphodiesterase (PDE) genes of S. mansoni, out of a total of 11 identified in its genome. We classify these PDEs by homology to human PDEs. Male worms displayed higher expression levels for all PDEs, in mature and juvenile worms, and schistosomula. Several functional complementation approaches were used to characterise these genes. We constructed a Trypanosoma brucei cell line in which expression of a cAMP-degrading PDE complements the deletion of TbrPDEB1/B2. Inhibitor screens of these cells expressing only either SmPDE4A, TbrPDEB1 or TbrPDEB2, identified highly potent inhibitors of the S. mansoni enzyme that elevated the cellular cAMP concentration. We further expressed most of the cloned SmPDEs in two pde1Δ/pde2Δ strains of Saccharomyces cerevisiae and some also in a specialised strain of Schizosacharomyces pombe. Five PDEs, SmPDE1, SmPDE4A, SmPDE8, SmPDE9A and SmPDE11 successfully complemented the S. cerevisiae strains, and SmPDE7var also complemented to a lesser degree, in liquid culture. SmPDE4A, SmPDE8 and SmPDE11 were further assessed in S. pombe for hydrolysis of cAMP and cGMP; SmPDE11 displayed considerable preferrence for cGMP over cAMP. These results and tools enable the pursuit of a rigorous drug discovery program based on inhibitors of S. mansoni PDEs.


Assuntos
Clonagem Molecular , Regulação Enzimológica da Expressão Gênica/fisiologia , Proteínas de Helminto/metabolismo , Diester Fosfórico Hidrolases/genética , Schistosoma mansoni/enzimologia , Schistosoma mansoni/genética , Animais , Linhagem Celular , Deleção de Genes , Perfilação da Expressão Gênica , Genoma Helmíntico , Proteínas de Helminto/genética , Masculino , Camundongos , Filogenia , Trypanosoma brucei brucei , Leveduras
3.
PLoS One ; 15(7): e0236199, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32673355

RESUMO

Antimicrobial-resistant and novel pathogens continue to emerge, outpacing efforts to contain and treat them. Therefore, there is a crucial need for safe and effective therapies. Ultraviolet-A (UVA) phototherapy is FDA-approved for several dermatological diseases but not for internal applications. We investigated UVA effects on human cells in vitro, mouse colonic tissue in vivo, and UVA efficacy against bacteria, yeast, coxsackievirus group B and coronavirus-229E. Several pathogens and virally transfected human cells were exposed to a series of specific UVA exposure regimens. HeLa, alveolar and primary human tracheal epithelial cell viability was assessed after UVA exposure, and 8-Oxo-2'-deoxyguanosine was measured as an oxidative DNA damage marker. Furthermore, wild-type mice were exposed to intracolonic UVA as an in vivo model to assess safety of internal UVA exposure. Controlled UVA exposure yielded significant reductions in Pseudomonas aeruginosa, Klebsiella pneumoniae, Escherichia coli, Enterococcus faecalis, Clostridioides difficile, Streptococcus pyogenes, Staphylococcus epidermidis, Proteus mirabilis and Candida albicans. UVA-treated coxsackievirus-transfected HeLa cells exhibited significantly increased cell survival compared to controls. UVA-treated coronavirus-229E-transfected tracheal cells exhibited significant coronavirus spike protein reduction, increased mitochondrial antiviral-signaling protein and decreased coronavirus-229E-induced cell death. Specific controlled UVA exposure had no significant effect on growth or 8-Oxo-2'-deoxyguanosine levels in three types of human cells. Single or repeated in vivo intraluminal UVA exposure produced no discernible endoscopic, histologic or dysplastic changes in mice. These findings suggest that, under specific conditions, UVA reduces various pathogens including coronavirus-229E, and may provide a safe and effective treatment for infectious diseases of internal viscera. Clinical studies are warranted to further elucidate the safety and efficacy of UVA in humans.


Assuntos
Infecções Bacterianas/terapia , Micoses/terapia , Infecções Oportunistas/terapia , Terapia Ultravioleta/métodos , Viroses/terapia , Animais , Apoptose/efeitos da radiação , Bactérias/efeitos da radiação , Infecções Bacterianas/microbiologia , Sobrevivência Celular/efeitos da radiação , Colo/microbiologia , Colo/efeitos da radiação , Coronavirus Humano 229E/efeitos da radiação , Dano ao DNA/efeitos da radiação , Modelos Animais de Doenças , Enterovirus Humano B/efeitos da radiação , Feminino , Células HeLa , Humanos , Mucosa Intestinal/microbiologia , Mucosa Intestinal/efeitos da radiação , Masculino , Camundongos , Micoses/microbiologia , Infecções Oportunistas/microbiologia , Cultura Primária de Células , Terapia Ultravioleta/efeitos adversos , Viroses/virologia , Leveduras/efeitos da radiação
4.
Bioresour Technol ; 315: 123790, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32707500

RESUMO

Single cell oil (SCO) represents an outstanding alternative to both fossil sources and vegetable oils from food crops waste. In this work, an innovative two-step process for the conversion of cellulosic paper mill waste into SCO was proposed and optimised. Hydrolysates containing glucose and xylose were produced by enzymatic hydrolysis of the untreated waste. Under the optimised reaction conditions (Cellic® CTec2 25 FPU/g glucan, 48 h, biomass loading 20 g/L), glucose and xylose yields of 95 mol% were reached. The undetoxified hydrolysate was adopted as substrate for a batch-mode fermentation by the oleaginous yeast Lipomyces starkeyi. Lipid yield, content for single cell, production and maximum oil productivity were 20.2 wt%, 37 wt%, 3.7 g/L and 2.0 g/L/d respectively. This new generation oil, obtained from a negative value industrial waste, represents a promising platform chemical for the production of biodiesel, biosurfactants, animal feed and biobased plastics.


Assuntos
Lipomyces , Fermentação , Hidrólise , Açúcares , Leveduras
5.
Nat Commun ; 11(1): 2670, 2020 05 29.
Artigo em Inglês | MEDLINE | ID: mdl-32471993

RESUMO

The assembly of active and self-propelled particles is an emerging strategy to create dynamic materials otherwise impossible. However, control of the complex particle interactions remains challenging. Here, we show that various dynamic interactions of active patchy particles can be orchestrated by tuning the particle size, shape, composition, etc. This capability is manifested in establishing dynamic colloidal bonds that are highly selective and directional, which greatly expands the spectrum of colloidal structures and dynamics by assembly. For example, we demonstrate the formation of colloidal molecules with tunable bond angles and orientations. They exhibit controllable propulsion, steering, reconfiguration as well as other dynamic behaviors that collectively reflect the bond properties. The working principle is further extended to the co-assembly of synthetic particles with biological entities including living cells, giving rise to hybrid colloidal molecules of various types, for example, a colloidal carrousel structure. Our strategy should enable active systems to perform sophisticated tasks in future such as selective cell treatment.


Assuntos
Coloides/química , Condutividade Elétrica , Interações de Partículas Elementares , Escherichia coli/química , Ciência dos Materiais/métodos , Estrutura Molecular , Nanoestruturas/química , Tamanho da Partícula , Leveduras/química
6.
Food Chem ; 328: 127110, 2020 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-32464557

RESUMO

In the present work we aimed to demonstrate the influence of inoculum starter in support high quality fermentation. Cocoa fermentations were performed in wooden boxes and eight yeasts strains were used in separated fermentations of fine cocoa, type Scavina, as starter inoculum. Temperature, pH, titirable acidity, reducing sugar and free amino acids were evaluated during or after fermentation. The influence of starters yeasts on the decrease of acidity, sugar concentration and free amino acids was significant. The strains Candida parapsilosis, Torulaspora delbrueckii and Pichia kluyveri showed greater changes in the reducing sugar and free amino acids in fermented cocoa beans. These results indicate the ability of yeast used as inoculum starter to modify the end condition and further enhance the quality of fine cocoa beans.


Assuntos
Cacau , Microbiologia de Alimentos/métodos , Leveduras , Aminoácidos/análise , Aminoácidos/metabolismo , Cacau/química , Cacau/metabolismo , Candida parapsilosis/genética , Candida parapsilosis/metabolismo , Chocolate , Fermentação , Concentração de Íons de Hidrogênio , Pichia/genética , Pichia/metabolismo , Sementes/química , Sementes/microbiologia , Temperatura , Torulaspora/genética , Torulaspora/metabolismo , Leveduras/genética , Leveduras/metabolismo
7.
J Med Microbiol ; 69(5): 712-720, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32368996

RESUMO

Introduction. Given the limited number of candidaemia studies in Iran, the profile of yeast species causing bloodstream infections (BSIs), especially in adults, remains limited. Although biochemical assays are widely used in developing countries, they produce erroneous results, especially for rare yeast species.Aim. We aimed to assess the profile of yeast species causing BSIs and to compare the accuracy of the Vitek 2 system and 21-plex PCR.Methodology. Yeast blood isolates were retrospectively collected from patients recruited from two tertiary care training hospitals in Tehran from 2015 to 2017. Relevant clinical data were mined. Identification was performed by automated Vitek 2, 21-plex PCR and sequencing of the internal transcribed spacer region (ITS1-5.8S-ITS2).Results. In total, 137 yeast isolates were recovered from 107 patients. The overall all-cause 30-day mortality rate was 47.7 %. Fluconazole was the most widely used systemic antifungal. Candida albicans (58/137, 42.3 %), Candida glabrata (30/137, 21.9 %), Candida parapsilosis sensu stricto (23/137, 16.8 %), Candida tropicalis (10/137, 7.3 %) and Pichia kudriavzevii (Candida krusei) (4/137, 2.9 %) constituted almost 90 % of the isolates and 10 % of the species detected were rare yeast species (12/137; 8.7 %). The 21-plex PCR method correctly identified 97.1 % of the isolates, a higher percentage than the Vitek 2 showed (87.6 %).Conclusion. C. albicans was the main cause of yeast-derived fungaemia in this study. Future prospective studies are warranted to closely monitor the epidemiological landscape of yeast species causing BSIs in Iran. The superiority of 21-plex PCR over automated Vitek 2 indicates its potential clinical utility as an alternative identification tool use in developing countries.


Assuntos
Fungemia/diagnóstico , Fungemia/epidemiologia , Fungemia/microbiologia , Reação em Cadeia da Polimerase Multiplex , Análise de Sequência de DNA , Leveduras/classificação , Leveduras/genética , Idoso , Idoso de 80 Anos ou mais , DNA Intergênico , Feminino , Fungemia/história , História do Século XXI , Humanos , Irã (Geográfico)/epidemiologia , Masculino , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase Multiplex/métodos , Reação em Cadeia da Polimerase Multiplex/normas , Análise de Sequência de DNA/métodos , Análise de Sequência de DNA/normas
8.
PLoS Negl Trop Dis ; 14(4): e0008268, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32352959

RESUMO

Data on causes of community-onset bloodstream infection in Myanmar are scarce. We aimed to identify etiological agents of bloodstream infections and patterns of antimicrobial resistance among febrile adolescents and adults attending Yangon General Hospital (YGH), Yangon, Myanmar. We recruited patients ≥12 years old with fever ≥38°C who attended YGH from 5 October 2015 through 4 October 2016. A standardized clinical history and physical examination was performed. Provisional diagnoses and vital status at discharge was recorded. Blood was collected for culture, bloodstream isolates were identified, and antimicrobial susceptibility testing was performed. Using whole-genome sequencing, we identified antimicrobial resistance mechanisms of Enterobacteriaceae and sequence types of Enterobacteriaceae and Streptococcus agalactiae. Among 947 participants, 90 (9.5%) had bloodstream infections (BSI) of which 82 (91.1%) were of community-onset. Of 91 pathogens isolated from 90 positive blood cultures, we identified 43 (47.3%) Salmonella enterica including 33 (76.7%) serovar Typhi and 10 (23.3%) serovar Paratyphi A; 20 (22.0%) Escherichia coli; 7 (7.7%) Klebsiella pneumoniae; 6 (6.6%), Staphylococcus aureus; 4 (4.4%) yeasts; and 1 (1.1%) each of Burkholderia pseudomallei and Streptococcus agalactiae. Of 70 Enterobacteriaceae, 62 (88.6%) were fluoroquinolone-resistant. Among 27 E. coli and K. pneumoniae, 18 (66.6%) were extended-spectrum beta-lactamase (ESBL)-producers, and 1 (3.7%) each were AmpC beta-lactamase- and carbapenemase-producers. Fluoroquinolone resistance was associated predominantly with mutations in the quinolone resistance-determining region. blaCTX-M-15 expression was common among ESBL-producers. Methicillin-resistant S. aureus was not detected. Fluoroquinolone-resistant, but not multiple drug-resistant, typhoidal S. enterica was the leading cause of community-onset BSI at a tertiary hospital in Yangon, Myanmar. Fluoroquinolone and extended-spectrum cephalosporin resistance was common among other Enterobactericeae. Our findings inform empiric management of severe febrile illness in Yangon and indicate that measures to prevent and control enteric fever are warranted. We suggest ongoing monitoring and efforts to mitigate antimicrobial resistance among community-onset pathogens.


Assuntos
Bactérias/isolamento & purificação , Resistência Microbiana a Medicamentos , Febre/etiologia , Sepse/epidemiologia , Leveduras/isolamento & purificação , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Bactérias/classificação , Bactérias/efeitos dos fármacos , Criança , Infecções Comunitárias Adquiridas/epidemiologia , Infecções Comunitárias Adquiridas/microbiologia , Hospitais Gerais , Humanos , Pessoa de Meia-Idade , Mianmar/epidemiologia , Estudos Prospectivos , Sepse/microbiologia , Leveduras/classificação , Leveduras/efeitos dos fármacos , Adulto Jovem
9.
Int J Food Microbiol ; 324: 108631, 2020 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-32388172

RESUMO

In the present work the microbial dynamics in wheat kernels were evaluated over time. The main aim of this research was to study the resistance of lactic acid bacteria (LAB) and yeasts associated to unprocessed cereals used for bread making during long term conservation. To this purpose four Triticum durum Desf. genotypes including two modern varieties (Claudio and Simeto) and two Sicilian wheat landraces (Russello and Timilia) were analysed by a combined culture-independent and -dependent microbiological approach after one, two or three years from cultivation and threshing. DNA based MiSeq Illumina technology was applied to reveal the entire bacterial composition of all semolina samples. The samples showed a different distribution of bacterial taxa per variety and time of storage. The groups mostly represented were Stenotrophomonas, Pseudomonas, Erwinia, Delftia and Sphingomonas genera, Enterobacteriaceae and Oxalobacteriaceae families, and Actinobacteria phylum. Among LAB, only Enterococcus genus was detected barely in a single sample (Simeto stored for one year) by the next generation sequencing, indicating that LAB remained unassigned or their abundances were below 0.1% or their DNAs were rendered inaccessible. Plate counts showed consistent differences in relation to genotypes and duration of storage, with the highest levels found for total mesophilic microorganisms detected up 6.8 Log CFU/g. Colonies of presumptive sourdough LAB were detected only in a few samples. Cocci constituted the major group of LAB in almost all samples. Following the enrichment procedure, almost all samples were characterised by the presence of acidifying microorganisms. All isolates collected before and after enrichment represented 28 different strains belonging to 10 species of Enterococcus, Lactobacillus and Pediococcus genera. The most resistant species during aging were Enterococcus faecium, Enterococcus durans, Lactobacillus brevis, Lactobacillus pentosus and Lactobacillus paracasei demonstrating that lactobacilli and enterococci are able to overcome the stressing conditions represented by cereal storage better than other LAB genera commonly found associated to cereals after harvest. Yeast community included mostly species with no interest in bread making.


Assuntos
Pão/microbiologia , Grão Comestível/microbiologia , Microbiota/genética , Triticum/microbiologia , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , Microbiologia de Alimentos , Armazenamento de Alimentos , Genótipo , Fatores de Tempo , Triticum/genética , Leveduras/genética , Leveduras/isolamento & purificação
10.
Int J Food Microbiol ; 327: 108652, 2020 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-32442778

RESUMO

Food-grade waste and side streams should be strictly kept in food use in order to achieve sustainable food systems. At present, the baking industry creates food-grade waste as excess and deformed products that are mainly utilized for non-food uses, such as bioethanol production. The purpose of this study was therefore to explore the potential of waste wheat bread recycling for fresh wheat bread production. Waste bread recycling was assessed without further processing or after tailored fermentation with lactic acid bacteria producing either dextran or ß-glucan exopolysaccharides. When non-treated waste bread slurry was added to new bread dough, bread quality (specific volume and softness) decreased with increasing content of waste bread addition. In situ EPS-production (dextran and microbial ß-glucan) significantly increased waste bread slurry viscosity and yielded residual fructose or glucose that could effectively replace the sugar added for yeast leavening. Furthermore, fermentation acidified waste bread matrix, thus improving the hygienic safety of the process. Bread containing dextran synthesized in situ by Weissella confusa A16 showed good technological quality. The produced dextran compensated the adverse effect of recycled bread on new bread quality attributes by 12% increase in bread specific volume and 37% decrease in crumb hardness. In this study, a positive technological outcome of the bread containing microbial ß-glucan was not detected. The waste bread fermented by W. confusa A16 containing dextran appears to enable safe bread recycling with low acidity and minimal quality loss.


Assuntos
Pão/microbiologia , Pão/normas , Fermentação , Indústria Alimentícia , Resíduos Industriais , Reciclagem/métodos , Triticum/microbiologia , Dextranos/metabolismo , Ácido Láctico/metabolismo , Weissella/metabolismo , Leveduras/metabolismo , beta-Glucanas/metabolismo
11.
Sci Total Environ ; 723: 138166, 2020 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-32224410

RESUMO

Vultures have evolved adaptive mechanisms to prevent infections associated with their scavenging lifestyle. However, food-borne exposure to antimicrobial pharmaceuticals can promote opportunistic infections with adverse outcomes. Here, we used multivariate and network analyses to increase understanding of the behavior of the yeast communities causing oral mycosis outbreaks recently reported in wild nestling cinereous (Aegypius monachus), griffon (Gyps fulvus) and Egyptian (Neophron percnopterus) vultures (CV, GV and EV, respectively) exposed to antibiotics from livestock farming. Common and unique yeast signatures (of Candida, Debaromyces, Diutina, Meyerozyma, Naganishia, Pichia, Rhodotorula, Trichosporon and Yarrowia species) associated with oral mycoses were identified in the three vulture species. Hierarchical clustering analysis (HCA) and principal component analysis (PCA) highlighted that oral lesions from CV and GV shared similar yeast signatures (of major causative pathogens of opportunistic mycoses, such as Candida albicans, Candida parapsilosis and Candida tropicalis), while EV had a distinct yeast signature (of uncommon pathogenic species, such as Candida dubliniensis, Candida zeylanoides, Pichia fermentans and Rhodotorula spp.). Synergistic interactions between yeast species from distinct fungal phyla were found in lesions from CV and GV, but not in EV. These formed co-occurrence subnetworks with partially or fully connected topology. This study reveals that the composition, assembly and co-occurrence patterns of the yeast communities causing oral mycoses differ between vulture species with distinct feeding habits and scavenging lifestyles. Yeast species widely pathogenic to humans and animals, and yeast co-occurrence relationships, are distinctive hallmarks of oral mycoses in CV and GV. These vulture species are more exposed to antibiotics from intensively medicated livestock carcasses provided in supplementary feeding stations and show higher incidence of thrush-like oral lesions than EV. These findings may be useful for development of new initiatives or changes in the conservation of these avian scavengers affected by anthropogenic activities.


Assuntos
Aves , Leveduras , Animais , Antibacterianos , Egito , Humanos , Gado
12.
J Water Health ; 18(2): 91-105, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32300084

RESUMO

There has been a rising interest in the levels, diversity and potential impacts of yeasts in aquatic environments. Some of the species isolated from such niches are known pathogens or have pathogenic and antifungal resistance features. This deems it necessary to understand the characteristics and potential health implications of such environmental yeasts species. Studies on these subjects are limited. Most studies on aquatic yeasts have linked them to water pollution. However, the current gold standards to determine microbial pollution of water use bacteria as the main indicator organisms. Including yeasts in water quality standards may provide a different dimension on the quality of water when determining its fit-for-use properties. Pathogenic yeasts cause superficial infections or life-threatening infections, especially in immunocompromised people. Some of the yeast species isolated in recent studies were resistant to commonly used antifungal agents of clinical and veterinary relevance. With the high prevalence rate of HIV in sub-Saharan Africa, particularly in South Africa, antifungal resistance is a public concern as it poses serious medical and economic challenges. Most available studies are concerned with clinical environments only. There is, thus, a need to review the literature that also focuses on aquatic environments.


Assuntos
Microbiologia da Água , Qualidade da Água , Leveduras , Antifúngicos , Testes de Sensibilidade Microbiana , África do Sul
13.
J Biosci Bioeng ; 130(1): 63-70, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32265130

RESUMO

Japanese sake production involves three processes: rice koji fermentation, seed mash fermentation, and main mash fermentation. Traditional seed mash (kimoto) production utilizes natural lactic acid produced by lactic acid bacteria for pure cultures of only sake yeast, preventing the growth of wild yeast and other unwanted bacteria. Recently, because kimoto production requires substantial time and labor, sake yeast mass-cultured in usual liquid medium has been used as a seed mash alternative. Sake quality is highly similar to that of kimoto, suggesting that they share similar component profiles. However, comparative component analyses of sake brewed with kimoto and sake brewed with cultured yeast are lacking. In this study, a time-course analysis of hydrophilic compounds in the main mash brewed with kimoto and with cultured yeast as well as a sensory evaluation of the products were performed. As a result, differences in various compounds and in umami taste level between sake brewed with kimoto and cultured yeast were detected. This is the first comparative analysis of changes in the component profile during sake main mash brewing using kimoto seed mash and cultured sake yeast; our results clarify the effects of kimoto seed mash on main mash brewing and sake quality.


Assuntos
Bebidas Alcoólicas/análise , Aromatizantes/química , Leveduras/metabolismo , Bebidas Alcoólicas/microbiologia , Fermentação , Aromatizantes/metabolismo , Humanos , Ácido Láctico/análise , Ácido Láctico/metabolismo , Lactobacillales/metabolismo , Oryza/química , Oryza/metabolismo , Oryza/microbiologia , Sementes/química , Sementes/metabolismo , Sementes/microbiologia , Paladar
14.
Nat Commun ; 11(1): 1871, 2020 04 20.
Artigo em Inglês | MEDLINE | ID: mdl-32313011

RESUMO

Base editors derived from CRISPR-Cas9 systems and DNA editing enzymes offer an unprecedented opportunity for the precise modification of genes, but have yet to be used at a genome-scale throughput. Here, we test the ability of the Target-AID base editor to systematically modify genes genome-wide by targeting yeast essential genes. We mutate around 17,000 individual sites in parallel across more than 1500 genes. We identify over 700 sites at which mutations have a significant impact on fitness. Using previously determined and preferred Target-AID mutational outcomes, we find that gRNAs with significant effects on fitness are enriched in variants predicted to be deleterious based on residue conservation and predicted protein destabilization. We identify key features influencing effective gRNAs in the context of base editing. Our results show that base editing is a powerful tool to identify key amino acid residues at the scale of proteomes.


Assuntos
Repetições Palindrômicas Curtas Agrupadas e Regularmente Espaçadas , Edição de Genes/métodos , Ensaios de Triagem em Larga Escala , Proteoma/genética , Leveduras/genética , Sequência de Bases , Sistemas CRISPR-Cas , Genes Essenciais , Genoma , Genoma Fúngico , Sequenciamento de Nucleotídeos em Larga Escala , Dados de Sequência Molecular , Mutagênese , Mutação , RNA Guia/genética
15.
Int J Food Microbiol ; 323: 108610, 2020 Jun 16.
Artigo em Inglês | MEDLINE | ID: mdl-32240882

RESUMO

Gioddu, also known as "Miciuratu", "Mezzoraddu" or "Latte ischidu" (literally meaning acidulous milk), is the sole variety of traditional Italian fermented milk. The aim of the present study was to elucidate the microbiota and the mycobiota occurring in artisan Gioddu sampled from three Sardinian producers by combining the results of viable counting on selective culture media and high-throughput sequencing. Physico-chemical parameters were also measured. The overall low pH values (3.80-4.22) recorded in the analyzed Gioddu samples attested the strong acidifying activity carried out by lactic acid bacteria during fermentation. Viable counts revealed the presence of presumptive lactococci, presumptive lactobacilli and non-Saccharomyces yeasts. A complex (kefir-like) microbiota of bacteria and yeasts was unveiled through sequencing. In more detail, Lactobacillus delbrueckii was found to dominate in Gioddu together with Streptococcus thermophilus, thus suggesting the establishment of a yogurt-like protocooperation. Unexpectedly, in all the three analyzed batches from two out of the three producers Lactobacillus kefiri was also detected, thus representing an absolute novelty, which suggests the presence of bioactive compounds (e.g. exopolysaccharides) similar to those characterizing milk kefir beverage. Mycobiota population, studied for the very first time in Gioddu, revealed a more complex composition, with Kluyveromyces marxianus, Galactomyces candidum and Geotrichum galactomyces constituting the core species. Further research is needed to disclose the eventual occurence in Gioddu of probiotic cultures and bioactive compounds (e.g. exopolysaccharides, angiotensin-converting enzyme inhibitory peptides and antimicrobial compounds) with potential health-benefits for the consumers.


Assuntos
Produtos Fermentados do Leite/microbiologia , Fermentação , Microbiologia de Alimentos , Lactobacillus/classificação , Leveduras/classificação , Animais , Produtos Fermentados do Leite/análise , Itália , Lactobacillus/isolamento & purificação , Lactobacillus/metabolismo , Probióticos/classificação , Probióticos/isolamento & purificação , Probióticos/metabolismo , Streptococcus thermophilus/isolamento & purificação , Streptococcus thermophilus/metabolismo , Leveduras/isolamento & purificação , Leveduras/metabolismo , Iogurte/microbiologia
16.
Science ; 368(6486): 78-84, 2020 04 03.
Artigo em Inglês | MEDLINE | ID: mdl-32241946

RESUMO

The design of modular protein logic for regulating protein function at the posttranscriptional level is a challenge for synthetic biology. Here, we describe the design of two-input AND, OR, NAND, NOR, XNOR, and NOT gates built from de novo-designed proteins. These gates regulate the association of arbitrary protein units ranging from split enzymes to transcriptional machinery in vitro, in yeast and in primary human T cells, where they control the expression of the TIM3 gene related to T cell exhaustion. Designed binding interaction cooperativity, confirmed by native mass spectrometry, makes the gates largely insensitive to stoichiometric imbalances in the inputs, and the modularity of the approach enables ready extension to three-input OR, AND, and disjunctive normal form gates. The modularity and cooperativity of the control elements, coupled with the ability to de novo design an essentially unlimited number of protein components, should enable the design of sophisticated posttranslational control logic over a wide range of biological functions.


Assuntos
Receptor Celular 2 do Vírus da Hepatite A/química , Engenharia de Proteínas , Mapas de Interação de Proteínas , Processamento de Proteína Pós-Traducional , Receptor Celular 2 do Vírus da Hepatite A/genética , Humanos , Lógica , Espectrometria de Massas , Biologia Sintética , Linfócitos T/metabolismo , Transcrição Genética , Leveduras/metabolismo
18.
Food Chem ; 322: 126710, 2020 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-32283363

RESUMO

Sourdough fermentation influences several properties of leavened baked goods also because Lactic acid bacteria (LAB) and yeasts produce bioactive peptides with a positive effect on human health. In an early study, three Lactobacilli strains (L. farciminis H3 and A11 and L. sanfranciscensis I4) possessing different proteolytic activities were used to produce sourdoughs containing peptides equipped with anti-inflammatory and/or antioxidant properties. This work was aimed to assess whether these properties could be retained after cooking. The selected LABs were used to produce breads from which low molecular weight (LMW-) peptides were extracted. The results provide solid proofs of keeping both antioxidant and anti-inflammatory activities of peptides from cooked products. Sequences of LMW-peptides either from doughs and breads were determined by mass spectrometry: differences have been noticed in amino acidic composition and in sequences, however, all the strains produce peptides equipped with antioxidant and anti-inflammatory activities.


Assuntos
Anti-Inflamatórios/análise , Antioxidantes/análise , Pão/análise , Pão/microbiologia , Lactobacillus/metabolismo , Anti-Inflamatórios/metabolismo , Antioxidantes/metabolismo , Fermentação , Farinha/análise , Microbiologia de Alimentos , Humanos , Peptídeos/análise , Peptídeos/metabolismo , Leveduras/metabolismo
19.
Bioresour Technol ; 309: 123329, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32315915

RESUMO

This work was aimed to strategically scale-up the yeast lipid production process using Reynolds number as a standard rheological parameter from 50 mL to 50 L scale. Oleaginous yeast Rhodotorula mucilaginosa IIPL32 was cultivated in xylose rich corncob hydrolysate. The fermentation process for growth and maturation was operated in fed-batch with two different C/N ratios of 40 and 60. The hydrodynamic parameters were used to standardize and represent the effect of rheology on the fermentation process. The growth pattern of the yeast was found similar in both shake flask and fermenter with the maximum growth observed at 48 h. The lipid yield increased from 0.4 g/L and 0.5 g/L to 1.3 g/L and 1.83 g/L for 50 mL to 50 L for C/N ratio 40 and 60 respectively. The increase in productivity during the growth phase and lipid accumulation during the maturation phase showed that the scale-up strategy was successful.


Assuntos
Rhodotorula , Zea mays , Fermentação , Xilose , Leveduras
20.
Bioresour Technol ; 309: 123374, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32320924

RESUMO

Feasible bioprocessing of lignocellulosic biomass requires the use of microbial strains with tolerance to inhibitor compounds and osmotic pressure, able to provide high product yield and productivity. In this sense, this study evaluated the potential of two non-conventional yeasts, Hansenula polymorpha CBS 4732 and Debaryomyces hansenii CBS 767, for use on biomass conversion in a biorefinery perspective. The ability of the strains to consume pentose and hexose sugars, to resist the toxic compounds present in hydrolysates, as well as to produce sugar alcohols and ethanol, was investigated. H. polymorpha showed highlighted resistance to toxic compounds and relevant ability to consume xylose and produce xylitol and ethanol under these conditions, at 37 °C. D. hansenii was a great producer of arabitol from glucose. The implications for sustainability due to the use of these yeasts in biorefineries was discussed. These results open up new perspectives for the development of the biorefinery sector.


Assuntos
Xilose , Leveduras , Fermentação , Pentoses , Xilitol
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