Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 99
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Artigo em Inglês | MEDLINE | ID: mdl-34499596

RESUMO

A Gram-stain-negative, coccus-shaped, obligately anaerobic, non-motile and non-spore-forming bacterium, designated strain JN500902T, was isolated from the mud in a fermentation cellar used continuously over 30 years for Chinese strong-flavour baijiu production. Colonies were white, circular, convex and smooth-edged. Growth was observed at 20-40 °C (optimum, 37 °C), at pH 5.0-10 (optimum, pH 7.5), with 0-2 % (w/v) NaCl and with 0-4 % (v/v) ethanol. The Biolog assay demonstrated positive reactions of strain JN500902T in the metabolism of l-fucose and pyruvate. The predominant cellular fatty acids (>10 %) consisted of C16 : 0 and C14 : 0. The major end metabolites of strain JN500902T were acetic acid and ethanol when incubated anaerobically in liquid reinforced clostridial medium. Acetate was the major organic acid end product. The complete genome size of strain JN500902T was 3 420 321 bp with 3327 identified genes. The G+C content was 43.5 mol%. Phylogenetic analysis based on 16S rRNA gene sequences affiliated strain JN500902T with the family Lachnospiraceae, having low sequence similarity (92.8 %) to the nearest type strain, Syntrophococcus sucromutans DSM 3224T and forming a clearly distinct branch. Core genome phylogenetic analysis of the isolate and 134 strains belonging to the family Lachnospiraceae also revealed that strain JN500902T was well-separated from other genera of this family as a monophyletic clade. The average nucleotide identity and amino acid identity values between strain JN500902T and 134 Lachnospiraceae strains were less than 74 and 65 %, respectively. Considering its polyphasic characteristics, strain JN500902T represents a novel genus and species within the family Lachnospiraceae, for which the name Novisyntrophococcus fermenticellae gen. nov., sp. nov. is proposed. The type strain is JN500902T (=CICC 24502T=JCM 33939T).


Assuntos
Clostridiales/classificação , Fermentação , Filogenia , Microbiologia do Solo , Anaerobiose , Técnicas de Tipagem Bacteriana , Composição de Bases , China , Clostridiales/isolamento & purificação , DNA Bacteriano/genética , Ácidos Graxos/química , RNA Ribossômico 16S/genética , Análise de Sequência de DNA
2.
Food Res Int ; 148: 110533, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34507779

RESUMO

Although the microbial diversity and structure in bean-based fermented foods have been widely studied, systematic studies on functional microbiota and mechanism of community forms in multi-microbial fermentation systems were still lacking. In this work, the metabolic pathway and functional potential of microbial community in broad bean paste (BBP) were investigated by metagenomics approach, and Staphylococcus, Bacillus, Weissella, Aspergillus and Zygosaccharomyces were found to be the potential predominant populations responsible for substrate alteration and flavor biosynthesis. Among them, Staphylococcus was the most abundant and widespread functional microbe, and closely related Staphylococcus species were diverse and ubiquitously distributed, with the opportunistic pathogen S. gallinarum being the most abundant Staphylococcus specie isolated from BBP. To explain the dominance status of S. gallinarum and species distributions of Staphylococcus genus, we tested the effects of abiotic and biotic factors on three Staphylococcus species using a tractable BBP model, demonstrating that adaptation to environmental conditions (environmental parameters and other functional microbes) led to the dominant position and species coexistence of Staphylococcus, and congeneric competition among Staphylococcus species further shaped ecological distributions of closely related Staphylococcus species. In general, this work revealed the metabolic potential of microbial community and distribution mechanism of Staphylococcus species during BBP fermentation, which could help traditional factories to more precisely control the safety and quality of bean-based fermented foods.


Assuntos
Alimentos e Bebidas Fermentados , Microbiota , Vicia faba , Fermentação , Staphylococcus
3.
Food Res Int ; 147: 110449, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34399451

RESUMO

Mud cellars have long been used as anaerobic bioreactors for the fermentation of Chinese strong-flavor Baijiu, where starchy raw materials (mainly sorghum) are metabolized to ethanol and various flavor compounds by multi-species microorganisms. Jiupei (fermented grains) and pit mud are two spatially linked microbial habitats in the mud cellar, yet their metabolic division of labor remains unclear. Here, we investigated the changes in environmental variables (e.g., temperature, oxygen, pH), key metabolites (e.g., ethanol, organic acids) and microbial communities in jiupei and pit mud during fermentation. Jiupei (low pH, high ethanol) and pit mud (neutral pH) provided two habitats with distinctly different environmental conditions for microbial growth. Lactic acid accumulated in jiupei, while butyric and hexanoic acids were mainly produced by microbes inhabiting the pit mud. Biomass analysis using quantitative real-time PCR showed that bacteria dominated the microbial consortia during fermentation, moreover cluster and principal coordinate analysis (PCoA) analysis showed that the bacterial communities of jiupei and pit mud were significantly divergent. The bacterial community diversity of jiupei decreased significantly during the fermentation process, and was relatively stable in pit mud. Lactobacillus dominated the jiupei bacterial community, and its relative abundance reached 98.0% at the end of fermentation. Clostridia (relative abundance: 42.9-85.5%) was the most abundant bacteria in pit mud, mainly distributed in the genus Hydrogenispora (5.3-68.4%). Fungal communities of jiupei and pit mud showed a similar succession pattern, and Kazachstania, Aspergillus and Thermoascus were the predominant genera. PICRUSt analysis demonstrated that enzymes participating in the biosynthesis of acetic and lactic acid were mainly enriched in jiupei samples, while the bacterial community in the pit mud displayed greater potential for butyric and hexanoic acid synthesis. Assays from an in vitro simulated fermentation further validated the roles of jiupei microbiota in acetic and lactic acid production, and these acids were subsequently metabolized to butyric and hexanoic acid by the pit mud microbiota. This work has demonstrated the synergistic cooperation between the microbial communities of jiupei and pit mud for the representative flavor formation of strong-flavor Baijiu.


Assuntos
Consórcios Microbianos , Microbiota , Bebidas Alcoólicas/análise , Bactérias/genética , Fermentação
4.
Appl Environ Microbiol ; 87(17): e0088521, 2021 08 11.
Artigo em Inglês | MEDLINE | ID: mdl-34160281

RESUMO

The mud cellar creates a unique microenvironment for the fermentation of strong-flavor baijiu (SFB). Recent research and long-term practice have highlighted the key roles of microbes inhabiting pit mud in the formation of SFB's characteristic flavor. A positive correlation between the quality of SFB and cellar age was extracted from practice; however, the evolutionary patterns of pit mud microbiome and driving factors remain unclear. Here, based on the variation regularity analysis of microbial community structure and metabolites of samples from cellars of different ages (∼30/100/300 years), we further investigated the effects of lactate and acetate (main microbial metabolites in fermented grains) on modulating the pit mud microbiome. Esters (50.3% to 64.5%) dominated the volatile compounds identified in pit mud, and contents of the four typical acids (lactate, hexanoate, acetate, and butyrate) increased with cellar age. Bacteria (9.5 to 10.4 log10 [lg] copies/g) and archaea (8.3 to 9.1 lg copies/g) mainly constituted pit mud microbiota, respectively dominated by Clostridia (39.7% to 81.2%) and Methanomicrobia (32.8% to 92.9%). An upward trend with cellar age characterized the relative and absolute abundance of the most predominant bacterial and archaeal genera, Caproiciproducens and Methanosarcina. Correlation analysis revealed significantly (P < 0.05) positive relationships between the two genera and major metabolites. Anaerobic fermentation with acetate and lactate as carbon sources enhanced the enrichment of Clostridia, and furthermore, the relative abundance of Caproiciproducens (40.9%) significantly increased after 15-day fed-batch fermentation with lactate compared with the initial pit mud (0.22%). This work presents a directional evolutionary pattern of pit mud microbial consortia and provides an alternative way to accelerate the enrichment of functional microbes. IMPORTANCE The solid-state anaerobic fermentation in a mud cellar is the most typical feature of strong-flavor baijiu (SFB). Metabolites produced by microbes inhabiting pit mud are crucial to create the unique flavor of SFB. Accordingly, craftspeople have always highlighted the importance of the pit mud microbiome and concluded by centuries of practice that the production rate of high-quality baijiu increases with cellar age. To deepen the understanding of the pit mud microbiome, we determined the microbial community and metabolites of different-aged pit mud, inferred the main functional groups, and explored the forces driving the microbial community evolution through metagenomic, metabolomic, and multivariate statistical analyses. The results showed that the microbial consortia of pit mud presented a regular and directional evolutionary pattern under the impact of continuous batch-to-batch brewing activities. This work provides insight into the key roles of the pit mud microbiome in SFB production and supports the production optimization of high-quality pit mud.


Assuntos
Archaea/isolamento & purificação , Bactérias/isolamento & purificação , Argila/microbiologia , Aromatizantes/metabolismo , Microbiota , Vinho/análise , Archaea/classificação , Archaea/genética , Archaea/metabolismo , Bactérias/classificação , Bactérias/genética , Bactérias/metabolismo , China , Fermentação , Aromatizantes/análise , Armazenamento de Alimentos/instrumentação , Vinho/microbiologia
5.
Crit Rev Biotechnol ; : 1-22, 2021 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-33985392

RESUMO

Owing to their numerous nutritional and bioactive functions, phospholipids (PLs), which are major components of biological membranes in all living organisms, have been widely applied as nutraceuticals, food supplements, and cosmetic ingredients. To date, PLs are extracted solely from soybean or egg yolk, despite the diverse market demands and high cost, owing to a tedious and inefficient manufacturing process. A microbial-based manufacturing process, specifically phospholipase D (PLD)-based biocatalysis and biotransformation process for PLs, has the potential to address several challenges associated with the soybean- or egg yolk-based supply chain. However, poor enzyme properties and inefficient microbial expression systems for PLD limit their wide industrial dissemination. Therefore, sourcing new enzyme variants with improved properties and developing advanced PLD expression systems are important. In the present review, we systematically summarize recent achievements and trends in the discovery, their structural properties, catalytic mechanisms, expression strategies for enhancing PLD production, and its multiple applications in the context of PLs. This review is expected to assist researchers to understand current advances in this field and provide insights for further molecular engineering efforts toward PLD-mediated bioprocessing.

6.
Carbohydr Polym ; 264: 118015, 2021 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-33910717

RESUMO

Owing to its outstanding water-retention ability, viscoelasticity, biocompatibility and non-immunogenicity, Hyaluronic acid (HA), a natural linear polymer alternating linked by d-glucuronic acid and N-acetylglucosamine, has been widely employed in cosmetic, medical and clinical applications. With the development of synthetic biology and bioprocessing optimization, HA production via microbial fermentation is an economical and sustainable alternative over traditional animal extraction methods. Indeed, recently Streptococci and other recombinant systems for HA synthesis has received increasing interests due to its technical advantages. This review summarizes the production of HA by microorganisms and demonstrates its synthesis mechanism, focusing on the current status in various production systems, as well as common synthetic biology strategies include driving more carbon flux into HA biosynthesis and regulating the molecular weight (MW), and finally discusses the major challenges and prospects.


Assuntos
Ácido Hialurônico/biossíntese , Ácido Hialurônico/química , Animais , Fermentação , Humanos , Hialuronoglucosaminidase/metabolismo , Microbiologia Industrial/métodos , Peso Molecular , Polímeros/química , Streptococcus/crescimento & desenvolvimento , Streptococcus/metabolismo , Biologia Sintética/métodos , Viscosidade
7.
Food Chem ; 357: 129625, 2021 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-33864999

RESUMO

Bean-based fermentation foods are usually ripened in open environment, which would lead to inconsistencies in flavor and quality between batches. The physicochemical metabolism and microbial community of seasonal broad bean paste (BBP) were compared to distinguish discriminant metabolites and unique taxa, as well as their specific reasons for different flavor and quality in this study. Here, we found that environmental variables led to the seasonal distribution of microbiota, and differential microorganisms further contributed to the inconsistency of flavor quality, in which Lactobacillales was responsible for the higher titratable acid and amino acid nitrogen concentration in winter pei, while Saccharomycetales benefited the formation of volatile flavor substances in autumn pei. Additionally, we compared the effect of different combinations of Lactobacillales with Zygosaccharomyces rouxii on the quality of BBP, and found that W. confusa was more suitable for BBP fermentation rather than T. halophilus in terms of sensory characteristics and physicochemical metabolites.

8.
Nutrients ; 13(3)2021 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-33800983

RESUMO

Hericium erinaceus (H. erinaceus) is widely studied as a medicinal and edible fungus. Recent studies have shown that H. erinaceus has protective effects for diseases, such as inflammatory bowel disease and cancer, which are related to gut microbiota. To investigate the benefits of H. erinaceus intake on gut microbiota and blood indices in adulthood, we recruited 13 healthy adults to consume H. erinaceus powder as a dietary supplement. Blood changes due to H. erinaceus consumption were determined by routine hematological examination and characterized by serum biochemical markers. Microbiota composition was profiled by 16S ribosomal RNA gene sequencing. Results showed that daily H. erinaceus supplementation increased the alpha diversity within the gut microbiota community, upregulated the relative abundance of some short-chain fatty acid (SCFA) producing bacteria (Kineothrix alysoides, Gemmiger formicilis, Fusicatenibacter saccharivorans, Eubacterium rectale, Faecalibacterium prausnitzii), and downregulated some pathobionts (Streptococcus thermophilus, Bacteroides caccae, Romboutsia timonensis). Changes within the gut microbiota were correlated with blood chemical indices including alkaline phosphatase (ALP), low-density lipoprotein (LDL), uric acid (UA), and creatinine (CREA). Thus, we found that the gut microbiota alterations may be part of physiological adaptations to a seven-day H. erinaceus supplementation, potentially influencing beneficial health effects.


Assuntos
Biomarcadores/sangue , Alimentos Fortificados , Microbioma Gastrointestinal/efeitos dos fármacos , Hericium , Adulto , Fosfatase Alcalina/metabolismo , Bactérias/classificação , Bactérias/genética , Creatinina/metabolismo , Ácidos Graxos Voláteis , Fezes/microbiologia , Feminino , Microbioma Gastrointestinal/genética , Gota/prevenção & controle , Humanos , Doenças Inflamatórias Intestinais/prevenção & controle , Cálculos Renais/prevenção & controle , Lipoproteínas LDL , Masculino , Projetos Piloto , RNA Ribossômico 16S/genética , Ácido Úrico
9.
Food Microbiol ; 98: 103766, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-33875202

RESUMO

Daqu, a brick-shaped product spontaneously fermented under an open environment, has been regarded as the starter of fermentation, raw enzyme preparation and raw materials for baijiu production. However, its contribution in baijiu fermentation has not been fully elaborated yet. Here, the effects of daqu microbiota on baijiu fermentation were investigated under both field-scale and lab-scale conditions. In field-scale baijiu fermentation, the dominant daqu microbes (average relative abundance>10.0%), including unclassified_Leuconostocaceae, Thermoascus, and Thermomyces, tended to dominate the early stage (0-7 d). However, the rare daqu microbes (average relative abundance <0.1%, e.g., Kazachstania) tended to dominate the middle and late stages (11-40 d). In addition, some genera showed differences in species diversity between daqu and fermented grains. The average relative abundance of Lactobacillus was over 75% during baijiu fermentation, and most of them were affiliated with Lactobacillus acetotolerans, while Lactobacillus crustorum dominated the Lactobacillus OTUs in daqu. The similar patterns were also observed during lab-scale baijiu fermentation. The results of function prediction showed the enriched metabolic pathways were associated with glycolysis and long-chain fatty acid esters in baijiu fermentation. These results improved the understanding of daqu microbiota function during baijiu fermentation and provided a basic theory to support the regulation of baijiu production.


Assuntos
Bebidas Alcoólicas/microbiologia , Lactobacillus/isolamento & purificação , Lactobacillus/metabolismo , Microbiota , China , Fermentação , Microbiologia de Alimentos , Lactobacillus/classificação , Lactobacillus/genética
10.
Food Res Int ; 140: 110037, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-33648263

RESUMO

As a widely used Asian starter culture, the quality of daqu can significantly affect the organoleptic characteristics of the final products, yet the microbial metabolic network involved in flavor development remains unclear. This study aims to investigate that network based on the dynamics of physicochemical properties, microbial community, and volatile compounds in medium-temperature daqu (MT-daqu) during spontaneous fermentation. Analyses using the metagenomic data set facilitated the gene repertoire overview of this ecosystem, indicating that Lactobacillales (mainly Weissella, Lactobacillus, and Pediococcus), Mucorales (mainly Lichtheimia), and Eurotiales (mainly Aspergillus, Rasamsonia and Byssochlamys) were the potential predominant populations successively responsible for the production of lytic enzymes and flavor precursors/compounds in MT-daqu. Flavor-relevant pathways were found to exist in multiple species, but only bacteria showed the potential to participate in butane-2,3-diol (e.g. Weissella, Lactobacillus, and Staphylococcus) and butanoate (Thermoactinomyces) metabolism, and only fungi were potentially involved in biosynthesis of guaiacol (Byssochlamys) and 4-vinylguaiacol (Aspergillus). Furthermore, a combined analysis revealed that the acidic thermal environment present in early phases was mainly due to the catabolic activities of Lactobacillales and Lichtheimia, which could contribute to the effective self-domestication of microbiota. The study helps elucidate the different metabolic roles of microorganisms and disclose the formation mechanism of daqu's partial functions, namely providing various aromatic substances/precursors and enzymes.


Assuntos
Metagenômica , Microbiota , Bebidas Alcoólicas/análise , Redes e Vias Metabólicas , Microbiota/genética , Temperatura
11.
Food Res Int ; 138(Pt A): 109737, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-33292931

RESUMO

Acetoin, giving a creamy yogurt aroma and buttery taste, exists in cereal vinegar as an important flavor substance and is mainly produced by the metabolism of Lactobacillus and Acetobacter during multispecies solid-state acetic acid fermentation. However, the impacts of Lactobacillus-Acetobacter interactions on acetoin accumulation and the microbial metabolism during acetic acid fermentation are not completely clear. Here, six strains isolated from vinegar fermentation culture and associated with acetoin metabolism, namely, Lactobacillus reuteri L-0, L. buchneri F2-6, L. brevis 4-20, L. fermentum M10-7, L. casei M1-6 and Acetobacter pasteurianus G3-2, were selected for microbial growth and metabolism analysis in monoculture and coculture fermentations. Lactobacillus sp. and A. pasteurianus G3-2 respectively utilized glucose and ethanol preferentially. In monocultures, L. casei M1-6 (183.7 mg/L) and A. pasteurianus G3-2 (121.0 mg/L) showed better acetoin-producing capacity than the others. In the bicultures with Lactobacillus sp. and A. pasteurianus G3-2, biomass analysis in the stationary phase demonstrated that significant growth depressions of Lactobacillus sp. occurred compared with monocultures, possibly due to intolerance to acetic acid produced by A. pasteurianus G3-2. Synergistic effect between Lactobacillus sp. and A. pasteurianus G3-2 on enhanced acetoin accumulation was identified, however, cocultures of two Lactobacillus strains could not apparently facilitate acetoin accumulation. Coculture of L. casei M1-6 and A. pasteurianus G3-2 showed the best performance in acetoin production amongst all mono-, bi- and triculture combinations, and the yield of acetoin increased from 1827.7 to 7529.8 mg/L following optimization of culture conditions. Moreover, the interactions of L. casei M1-6 and A. pasteurianus G3-2 regulated the global metabolism of vinegar microbiota during fermentation through performing in situ bioaugmentation, which could accelerate the production of acetic acid, lactic acid, acetoin, ethyl acetate, ethyl lactate, ligustrazine and other important flavoring substances. This work provides a promising strategy for the production of acetoin-rich vinegar through Lactobacillus sp.-A. pasteurianus joint bioaugmentation.


Assuntos
Acetobacter , Lactobacillus casei , Microbiota , Ácido Acético/análise , Acetoína , Grão Comestível/química , Fermentação
12.
Biotechnol Adv ; 45: 107655, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-33186607

RESUMO

Keratinases are unique among proteolytic enzymes for their ability to degrade recalcitrant insoluble proteins, and they are of critical importance in keratin waste management. Over the past few decades, researchers have focused on discovering keratinase producers, as well as producing and characterizing keratinases. The application potential of keratinases has been investigated in the feed, fertilizer, leathering, detergent, cosmetic, and medical industries. However, the commercial availability of keratinases is still limited due to poor productivity and properties, such as thermostability, storage stability and resistance to organic reagents. Advances in molecular biotechnology have provided powerful tools for enhancing the production and functional properties of keratinase. This critical review systematically summarizes the application potential of keratinase, and in particular certain newly discovered catalytic capabilities. Furthermore, we provide comprehensive insight into mechanistic and molecular aspects of keratinases including analysis of gene sequences and protein structures. In addition, development and current advances in protein engineering of keratinases are summarized and discussed, revealing that the engineering of protein domains such as signal peptides and pro-peptides has become an important strategy to increase production of keratinases. Finally, prospects for further development are also proposed, indicating that advanced protein engineering technologies will lead to improved and additional commercial keratinases for various industrial applications.


Assuntos
Biotecnologia , Peptídeo Hidrolases , Indústrias , Queratinas/genética , Peptídeo Hidrolases/genética
13.
Food Microbiol ; 92: 103559, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32950153

RESUMO

Symphony orchestra of multi-microorganisms characterizes the solid-state acetic acid fermentation process of Chinese cereal vinegars. Lactate is the predominant non-volatile acid and plays indispensable roles in flavor formation. This study investigated the microbial consortia driving the metabolism of D-/l-lactate during fermentation. Sequencing analysis based on D-/l-lactate dehydrogenase genes demonstrated that Lactobacillus (relative abundance: > 95%) dominated the production of both d-lactate and l-lactate, showing species-specific features between the two types. Lactobacillus helveticus (>65%) and L. reuteri (~80%) respectively dominated l- and d-lactate-producing communities. D-/l-lactate production and utilization capabilities of eight predominant Lactobacillus strains were determined by culture-dependent approach. Subsequently, D-/l-lactate producer L. plantarum M10-1 (d:l ≈ 1:1), l-lactate producer L. casei 21M3-1 (D:L ≈ 0.2:9.8) and D-/l-lactate utilizer Acetobacter pasteurianus G3-2 were selected to modulate the metabolic flux of D-/l-lactate of microbial consortia. The production ratio of D-/l-lactate was correspondingly shifted coupling with microbial consortia changes. Bioaugmentation with L.casei 21M3-1 merely enhanced l-lactate production, displaying ~4-fold elevation at the end of fermentation. Addition of L.plantarum M10-1 twice increased both D- and l-lactate production, while A. pasteurianus G3-2 decreased the content of D-/l-isomer. Our results provided an alternative strategy to specifically manipulate the metabolic flux within microbial consortia of certain ecological niches.


Assuntos
Ácido Acético/metabolismo , Bactérias/metabolismo , Grão Comestível/microbiologia , Ácido Láctico/metabolismo , Microbiota , Ácido Acético/análise , Acetobacter/genética , Acetobacter/metabolismo , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , Grão Comestível/química , Grão Comestível/metabolismo , Etanol/metabolismo , Fermentação , Microbiologia de Alimentos , Lactobacillus/genética , Lactobacillus/metabolismo
14.
Nutrients ; 12(9)2020 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-32932919

RESUMO

Liver fibrosis is a pathological process with intrahepatic diffused deposition of the excess extracellular matrix, which leads to various chronic liver diseases. Drugs with high efficacy and low toxicity for liver fibrosis are still unavailable. Antrodia camphorata has antioxidant, antivirus, antitumor and anti-inflammation roles, and has been used to treat liver diseases in the population. However, the hepatoprotective effects of A. camphorata spores and the mechanisms behind it have not been investigated. In this study, we evaluate the hepatoprotective effect of spore powder of A. camphorata (SP, 100 mg/kg/day or 200 mg/kg/day) on carbon tetrachloride (CCl4)-induced liver fibrosis in mice. SP groups reduced serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activities compared with the CCl4 group. SP also showed a decrease in hydroxyproline (Hyp) content in liver tissues. SP improved cell damage and reduced collagen deposition by H&E, Sirius red and Masson staining. Furthermore, SP down-regulated the mRNA levels of α-SMA and Col 1, and the protein expression of α-smooth muscle actin (α-SMA), collagen I (Col 1), tumor necrosis factor alpha (TNF-α), toll like receptor 4 (TLR4) and nuclear factor-Κb (NF-κB) p65. In summary, SP has an ameliorative effect on hepatic fibrosis, probably by inhibiting the activation of hepatic stellate cells, reducing the synthesis of extracellular matrix.


Assuntos
Antioxidantes/farmacologia , Cirrose Hepática/tratamento farmacológico , Polyporales/metabolismo , Esporos/metabolismo , Animais , Tetracloreto de Carbono , Modelos Animais de Doenças , Fígado/efeitos dos fármacos , Masculino , Camundongos , Camundongos Endogâmicos BALB C
15.
Cell Commun Signal ; 18(1): 151, 2020 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-32933544

RESUMO

BACKGROUND: Hepatic fibrosis is a pathological response of the liver to a variety of chronic stimuli. Hepatic stellate cells (HSCs) are the major source of myofibroblasts in the liver. Follistatin like 1 (Fstl1) is a secreted glycoprotein induced by transforming growth factor-ß1 (TGF-ß1). However, the precise functions and regulation mechanisms of Fstl1 in liver fibrogenesis remains unclear. METHODS: Hepatic stellate cell (HSC) line LX-2 stimulated by TGF-ß1, primary culture of mouse HSCs and a model of liver fibrosis induced by CCl4 in mice was used to assess the effect of Fstl1 in vitro and in vivo. RESULTS: Here, we found that Fstl1 was significantly up regulated in human and mouse fibrotic livers, as well as activated HSCs. Haplodeficiency of Fstl1 or blockage of Fstl1 with a neutralizing antibody 22B6 attenuated CCl4-induced liver fibrosis in vivo. Fstl1 modulates TGF-ß1 classic Samd2 and non-classic JNK signaling pathways. Knockdown of Fstl1 in HSCs significantly ameliorated cell activation, cell migration, chemokines C-C Motif Chemokine Ligand 2 (CCL2) and C-X-C Motif Chemokine Ligand 8 (CXCL8) secretion and extracellular matrix (ECM) production, and also modulated microRNA-29a (miR29a) expression. Furthermore, we identified that Fstl1 was a target gene of miR29a. And TGF-ß1 induction of Fstl1 expression was partially through down regulation of miR29a in HSCs. CONCLUSIONS: Our data suggests TGF-ß1-miR29a-Fstl1 regulatory circuit plays a key role in regulation the HSC activation and ECM production, and targeting Fstl1 may be a strategy for the treatment of liver fibrosis. Video Abstract.

16.
Bioprocess Biosyst Eng ; 43(12): 2201-2207, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32661565

RESUMO

To improve nicotinic acid (NA) yield and meet industrial application requirements of sodium alginate-polyvinyl alcohol (SA-PVA) immobilized cells of Pseudomonas putida mut-D3 harboring nitrilase, inorganic materials were added to the SA-PVA immobilized cells to improve mechanical strength and mass transfer performance. The concentrations of inorganic materials were optimized to be 2.0% silica and 0.6% CaCO3. The optimal pH and temperature for SA-PVA immobilized cells and composite immobilized cells were both 8.0 and 45 °C, respectively. The half-lives of composite immobilized cells were 271.48, 150.92, 92.92 and 33.12 h, which were 1.40-, 1.35-, 1.22- and 1.63-fold compared to SA-PVA immobilized cells, respectively. The storage stability of the composite immobilized cells was slightly increased. The composite immobilized cells could convert 14 batches of 3-cyanopyridine with feeding concentration of 250 mM and accumulate 418 g ·L-1 nicotinic acid, while the SA-PVA immobilized cells accumulated 346 g L-1 nicotinic acid.

17.
Macromol Biosci ; 20(9): e2000073, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32691954

RESUMO

Keratin is widely recognized as a high-quality renewable protein resource for biomedical applications. Despite their extensive existence, keratin resources such as feathers, wool, and hair exhibit high stability and mechanical properties because of their high disulfide bond content. Consequently, keratin extraction is challenging and its application is greatly hindered. In this work, a biological extraction strategy is proposed for the preparation of bioactive keratin and the fabrication of self-assembled keratin hydrogels (KHs). Based on moderate and controlled hydrolysis by keratinase, keratin with a high molecular weight of approximately 45 and 28 kDa that retain its intrinsic bioactivities is obtained. The keratin products show excellent ability to promote cell growth and migration and are conferred with significant antioxidant ability because of their intrinsically high cysteine content. In addition, without the presence of any cross-linking agent, the extracted keratin can self-assemble into injectable hydrogels. The KHs exhibit a porous network structure and 3D culture ability, showing potential in promoting wound healing. This enzyme-driven keratin extraction strategy opens up a new approach for the preparation of keratin that can self-assemble into injectable hydrogels for biomedical engineering.

18.
J Proteomics ; 224: 103851, 2020 07 30.
Artigo em Inglês | MEDLINE | ID: mdl-32485395

RESUMO

Colletotrichum lini is used as an industrial stain for the dihydroxylation of steroid compound dehydroepiandrosterone (DHEA) to biosynthesize 3ß,7α,15α-trihydroxy-5-androstene-17-one (7α,15α-diOH-DHEA), a key intermediate of the most popular oral contraceptive "Yasmin". This work aimed to enhance 7α,15α-diOH-DHEA production in C. lini CGMCC 6051 through ethanol induction. With 0.6% (v/v) ethanol induction and 10 g/L DHEA concentration, the 7α,15α-diOH-DHEA molar yield reached 58.8%, which was increased by 67.5% than that of the control. iTRAQ-based quantitative proteomic analysis was applied to explore the probable molecular mechanism of C. lini response to ethanol induction. A total of 50 differential expressed proteins was affected by ethanol induction, and could be related to multiple metabolic pathways. Most of differently expressed proteins were functionally mapped into pathways of transport, steroids metabolism, or redox reaction. Other proteins for energy, transcription and translation, and carbohydrate metabolism might have important roles in the cellular response to ethanol induction. In addition, the levels of cytochrome P450 and NAD(P)H-cytochrome P450 reductase were remarkably higher under ethanol induction, and their functions on DHEA dihydroxylation were first proposed in C. lini. Our results provide critical clues in revealing the dihydroxylation mechanism and are important for efficient microbiological hydroxylation of steroidal compounds in the future. BIOLOGICAL SIGNIFICANCE: iTRAQ strategy was first used to compare the proteomes of ethanol induction during the dihydroxylation reaction by Colletotrichum lini CGMCC 6051. The changes in protein provided a comprehensive overview of DHEA dihydroxylation in C. lini, including the proteins for steroids metabolism, redox reaction, transport, transcription and translation, energy and carbohydrate metabolism. Cytochrome P450, NADPH-cytochrome P450 reductase, and NADH-cytochrome b5 reductase were highlighted due to their outstanding contribution to DHEA dihydroxylation. The results help us understand the molecular mechanism underlying ethanol induction in C. lini and would guide strain engineering to further improve dihydroxylation efficiency.


Assuntos
Colletotrichum , Desidroepiandrosterona , Etanol , Proteômica
19.
J Biotechnol ; 320: 57-65, 2020 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-32569793

RESUMO

Keratinase is capable of distinctive degradation of keratin, which provides an eco-friendly approach for keratin waste management towards sustainable development. In this study, the recombinant keratinase (KERBP) from Brevibacillus parabrevis was successfully expressed in Escherichia coli. The purified KERBP had the specific activity of 6005.3 U/mg. It showed remarkable tolerance to various surfactants and also no collagenolytic activity. However, the moderate thermal stability limited its further application. Thus, protein engineering was further adopted to improve its stability. The variants of T218S, S236C and N181D were constructed by site-directed mutagenesis and combinatorial mutagenesis. Compared with the wild type, the t1/2 at 60 °C for the variants T218S, S236C and N181D were 3.05-, 1.18- and 1-fold increase, respectively. Moreover, the double variants N181D-T218S and N181D-S236C significantly improved thermostability with 5.1 and 2.9 °C increase of T50, and prolonging t1/2 at 60 °C with 4.09 and 1.54-fold, respectively. And the catalytic efficiency of the T218S and N181D-T218S variants was also significantly improved. Furthermore, the keratinase displayed favorable ability to dehair wool from skin within 7 h, which showed potential in leather dehairing. Our work contributes to a further insight into the thermostability of keratinase and offers a promising alternative for industrial leather application.


Assuntos
Proteínas de Bactérias , Brevibacillus , Peptídeo Hidrolases , Engenharia de Proteínas/métodos , Proteínas Recombinantes , Animais , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Brevibacillus/enzimologia , Brevibacillus/genética , Escherichia coli/genética , Peptídeo Hidrolases/química , Peptídeo Hidrolases/genética , Peptídeo Hidrolases/metabolismo , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Proteínas Recombinantes/farmacologia , Lã/efeitos dos fármacos , Lã/metabolismo
20.
Colloids Surf B Biointerfaces ; 194: 111158, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32540765

RESUMO

Keratin is widely used in the biomaterial application, but the keratin prepared by the physical or chemical approach has relatively low molecular weight and mechanical properties. Here we report the preparation of high molecular keratin (HMK) with molecular weight of 120 kDa via multi-enzyme cascade pathway and its application in wound healing. Briefly, we prepared the soluble keratin from wool by keratinase and improved the molecular weight of keratin by transglutaminase (TGase). The HMK was coelectrospun with poly(3-hydroxybutyric acid-co-3-hydroxyvaleric acid) (PHBV) and the prepared nanofibrous mats demonstrated improved mechanical properties. Ag nanoparticles (AgNPs) were synthesized on the nanofibers via in situ bioreduction, using the above-mentioned keratinase as the reducing agent. It is demonstrated that the PHBV/HMK/AgNPs nanofibrous mats possess favorable antibacterial properties and good biocompatibility. Moreover, in vivo wound healing assessment, the PHBV/HMK/AgNPs membrane displayed better wound healing ability than the control group. These results indicate that PHBV/HMK/AgNPs mats exhibit significant potential in tissue engineering.


Assuntos
Queratinas , Nanopartículas Metálicas , Nanofibras , Cicatrização , Animais , Prata
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...