Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 13 de 13
Filtrar
Mais filtros

Base de dados
Tipo de documento
Intervalo de ano de publicação
1.
Int J Mol Sci ; 25(9)2024 Apr 29.
Artigo em Inglês | MEDLINE | ID: mdl-38732060

RESUMO

The human gut microbiota, an intricate ecosystem within the gastrointestinal tract, plays a pivotal role in health and disease. Prebiotics, non-digestible food ingredients that beneficially affect the host by selectively stimulating the growth and/or activity of beneficial microorganisms, have emerged as a key modulator of this complex microbial community. This review article explores the evolution of the prebiotic concept, delineates various types of prebiotics, including fructans, galactooligosaccharides, xylooligosaccharides, chitooligosaccharides, lactulose, resistant starch, and polyphenols, and elucidates their impact on the gut microbiota composition. We delve into the mechanisms through which prebiotics exert their effects, particularly focusing on producing short-chain fatty acids and modulating the gut microbiota towards a health-promoting composition. The implications of prebiotics on human health are extensively reviewed, focusing on conditions such as obesity, inflammatory bowel disease, immune function, and mental health. The review further discusses the emerging concept of synbiotics-combinations of prebiotics and probiotics that synergistically enhance gut health-and highlights the market potential of prebiotics in response to a growing demand for functional foods. By consolidating current knowledge and identifying areas for future research, this review aims to enhance understanding of prebiotics' role in health and disease, underscoring their importance in maintaining a healthy gut microbiome and overall well-being.


Assuntos
Microbioma Gastrointestinal , Prebióticos , Humanos , Probióticos/farmacologia , Obesidade/microbiologia , Obesidade/dietoterapia , Obesidade/metabolismo , Ácidos Graxos Voláteis/metabolismo , Animais , Doenças Inflamatórias Intestinais/microbiologia , Doenças Inflamatórias Intestinais/dietoterapia
2.
Molecules ; 22(5)2017 May 19.
Artigo em Inglês | MEDLINE | ID: mdl-28534845

RESUMO

Minor ginsenosides, such as compound K, Rg3(S), which can be produced by deglycosylation of ginsenosides Rb1, showed strong anti-cancer effects. However, the anticancer effects of gypenoside LXXV, which is one of the deglycosylated shapes of ginsenoside Rb1, is still unknown due to the rarity of its content in plants. Here, we cloned and characterized a novel ginsenoside-transforming ß-glucosidase (BglG167b) derived from Microbacterium sp. Gsoil 167 which can efficiently hydrolyze gypenoside XVII into gypenoside LXXV, and applied it to the production of gypenoside LXXV at the gram-scale with high specificity. In addition, the anti-cancer activity of gypenoside LXXV was investigated against three cancer cell lines (HeLa, B16, and MDA-MB231) in vitro. Gypenoside LXXV significantly reduced cell viability, displaying an enhanced anti-cancer effect compared to gypenoside XVII and Rb1. Taken together, this enzymatic method would be useful in the preparation of gypenoside LXXV for the functional food and pharmaceutical industries.


Assuntos
Actinobacteria/química , Antineoplásicos Fitogênicos/metabolismo , Proteínas de Bactérias/metabolismo , Ginsenosídeos/metabolismo , beta-Glucosidase/metabolismo , Actinobacteria/enzimologia , Animais , Antineoplásicos Fitogênicos/isolamento & purificação , Antineoplásicos Fitogênicos/farmacologia , Proteínas de Bactérias/genética , Biotransformação , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Clonagem Molecular , Escherichia coli/genética , Escherichia coli/metabolismo , Expressão Gênica , Ginsenosídeos/isolamento & purificação , Ginsenosídeos/farmacologia , Gynostemma , Células HeLa , Humanos , Melanoma Experimental/tratamento farmacológico , Camundongos , Panax/química , Extratos Vegetais/biossíntese , Extratos Vegetais/isolamento & purificação , Extratos Vegetais/farmacologia , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , beta-Glucosidase/genética
3.
Antimicrob Agents Chemother ; 60(4): 2232-40, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26810657

RESUMO

Bacterial persisters are a small fraction of quiescent cells that survive in the presence of lethal concentrations of antibiotics. They can regrow to give rise to a new population that has the same vulnerability to the antibiotics as did the parental population. Although formation of bacterial persisters in the presence of various antibiotics has been documented, the molecular mechanisms by which these persisters tolerate the antibiotics are still controversial. We found that amplification of the fumarate reductase operon (FRD) inEscherichia coliled to a higher frequency of persister formation. The persister frequency ofE. coliwas increased when the cells contained elevated levels of intracellular fumarate. Genetic perturbations of the electron transport chain (ETC), a metabolite supplementation assay, and even the toxin-antitoxin-relatedhipA7mutation indicated that surplus fumarate markedly elevated theE. colipersister frequency. AnE. colistrain lacking succinate dehydrogenase (SDH), thereby showing a lower intracellular fumarate concentration, was killed ∼1,000-fold more effectively than the wild-type strain in the stationary phase. It appears thatSDHandFRDrepresent a paired system that gives rise to and maintainsE. colipersisters by producing and utilizing fumarate, respectively.


Assuntos
Antibacterianos/farmacologia , Proteínas de Bactérias/genética , Farmacorresistência Bacteriana Múltipla/genética , Escherichia coli/efeitos dos fármacos , Regulação Bacteriana da Expressão Gênica , Succinato Desidrogenase/genética , Ampicilina/farmacologia , Proteínas de Bactérias/metabolismo , Ciclo do Ácido Cítrico/efeitos dos fármacos , Ciclo do Ácido Cítrico/genética , Transporte de Elétrons/efeitos dos fármacos , Transporte de Elétrons/genética , Escherichia coli/enzimologia , Escherichia coli/genética , Fumaratos/metabolismo , Perfilação da Expressão Gênica , Biblioteca Gênica , Canamicina/farmacologia , Testes de Sensibilidade Microbiana , Norfloxacino/farmacologia , Óperon , Succinato Desidrogenase/deficiência
4.
Plant Cell Physiol ; 55(12): 2177-88, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25320211

RESUMO

Ginseng is a medicinal herb that requires cultivation under shade conditions, typically for 4-6 years, before harvesting. The principal components of ginseng are ginsenosides, glycosylated tetracyclic terpenes. Dammarene-type ginsenosides are classified into two groups, protopanaxadiol (PPD) and protopanaxatriol (PPT), based on their hydroxylation patterns, and further diverge to diverse ginsenosides through differential glycosylation. Three early enzymes, dammarenediol-II synthase (DS) and two P450 enzymes, protopanaxadiol synthase (PPDS) and protopanaxatriol synthase (PPTS), have been reported, but glycosyltransferases that are necessary to synthesize specific ginsenosides have not yet been fully identified. To discover glycosyltransferases responsible for ginsenoside biosynthesis, we sequenced and assembled the ginseng transcriptome de novo and characterized two UDP-glycosyltransferases (PgUGTs): PgUGT74AE2 and PgUGT94Q2. PgUGT74AE2 transfers a glucose moiety from UDP-glucose (UDP-Glc) to the C3 hydroxyl groups of PPD and compound K to form Rh2 and F2, respectively, whereas PgUGT94Q2 transfers a glucose moiety from UDP-Glc to Rh2 and F2 to form Rg3 and Rd, respectively. Introduction of the two UGT genes into yeast together with PgDS and PgPPDS resulted in the de novo production of Rg3. Our results indicate that these two UGTs are key enzymes for the synthesis of ginsenosides and provide a method for producing specific ginsenosides through yeast fermentation.


Assuntos
Ginsenosídeos/metabolismo , Glicosiltransferases/metabolismo , Panax/enzimologia , Glicosiltransferases/genética , Dados de Sequência Molecular , Panax/química , Panax/genética , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Raízes de Plantas/química , Raízes de Plantas/enzimologia , Raízes de Plantas/genética , Plantas Medicinais , Sapogeninas/metabolismo
5.
Appl Microbiol Biotechnol ; 98(15): 6701-13, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24752842

RESUMO

The genomic stability and integrity of host strains are critical for the production of recombinant proteins in biotechnology. Bacterial genomes contain numerous jumping genetic elements, the insertion sequences (ISs) that cause a variety of genetic rearrangements, resulting in adverse effects such as genome and recombinant plasmid instability. To minimize the harmful effects of ISs on the expression of recombinant proteins in Escherichia coli, we developed an IS-free, minimized E. coli strain (MS56) in which about 23 % of the genome, including all ISs and many unnecessary genes, was removed. Here, we compared the expression profiles of recombinant proteins such as tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) and bone morphogenetic protein-2 (BMP2) in MG1655 and MS56. Hopping of ISs (IS1, IS3, or IS5) into the TRAIL and BMP2 genes occurred at the rate of ~10(-8)/gene/h in MG1655 whereas such events were not observed in MS56. Even though IS hopping occurred very rarely (10(-8)/gene/h), cells containing the IS-inserted TRAIL and BMP2 plasmids became dominant (~52 % of the total population) 28 h after fermentation began due to their growth advantage over cells containing intact plasmids, significantly reducing recombinant protein production in batch fermentation. Our findings clearly indicate that IS hopping is detrimental to the industrial production of recombinant proteins, emphasizing the importance of the development of IS-free host strains.


Assuntos
Escherichia coli/genética , Mutagênese Insercional , Proteínas Recombinantes/biossíntese , Escherichia coli/metabolismo , Plasmídeos/genética , Plasmídeos/metabolismo , Proteínas Recombinantes/genética , Regulação para Cima
6.
Appl Environ Microbiol ; 79(3): 774-82, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23160128

RESUMO

Despite numerous approaches for the development of l-threonine-producing strains, strain development is still hampered by the intrinsic inefficiency of metabolic reactions caused by simple diffusion and random collisions of enzymes and metabolites. A scaffold system, which can promote the proximity of metabolic enzymes and increase the local concentration of intermediates, was reported to be one of the most promising solutions. Here, we report an improvement in l-threonine production in Escherichia coli using a DNA scaffold system, in which a zinc finger protein serves as an adapter for the site-specific binding of each enzyme involved in l-threonine production to a precisely ordered location on a DNA double helix to increase the proximity of enzymes and the local concentration of metabolites to maximize production. The optimized DNA scaffold system for l-threonine production significantly increased the efficiency of the threonine biosynthetic pathway in E. coli, substantially reducing the production time for l-threonine (by over 50%). In addition, this DNA scaffold system enhanced the growth rate of the host strain by reducing the intracellular concentration of toxic intermediates, such as homoserine. Our DNA scaffold system can be used as a platform technology for the construction and optimization of artificial metabolic pathways as well as for the production of many useful biomaterials.


Assuntos
Vias Biossintéticas/genética , Escherichia coli/enzimologia , Escherichia coli/metabolismo , Engenharia Metabólica , Treonina/biossíntese , DNA/metabolismo , Escherichia coli/genética , Substâncias Macromoleculares , Complexos Multienzimáticos , Ligação Proteica , Dedos de Zinco
7.
Front Nutr ; 10: 1249358, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38024360

RESUMO

Introduction: Green banana flour can be used as a prebiotic due to its ability to promote gut health and provide several health benefits. In this study, we investigated whether feeding mice green banana flour at different doses would alter intestinal microbiota composition. Methods: We fed C57BL/6N mice either a Low-dose (500 mg/kg/day) or High-dose (2000 mg/kg/day) of green banana flour daily for 3 weeks, and fecal samples were collected on days 0, 14, and 21 for microbiota analysis. Results: Our results showed that the composition of intestinal microbiota was significantly altered by day 21, regardless of the dose. Notably, the consumption of green banana flour increased the presence of beneficial bacteria, including Coriobacteriaceae_UCG-002, Turicibacter, Parasutterella, Gastranaerophilales_ge, and RF39_ge. These changes in the intestinal microorganisms were accompanied by increased biological processes such as amino acid biosynthesis and secondary metabolite biosynthesis. Conversely, the consumption of green banana flour resulted in a decrease in biological processes related to carbohydrate degradation, glycerol degradation, and similar functions. Discussion: These results emphasize the potential of green banana flour as a prebiotic that can benefit the gut microbiome.

8.
Nutrients ; 15(11)2023 Jun 02.
Artigo em Inglês | MEDLINE | ID: mdl-37299573

RESUMO

Alterations in the intestinal microbial flora are known to cause various diseases, and many people routinely consume probiotics or prebiotics to balance intestinal microorganisms and the growth of beneficial bacteria. In this study, we selected a peptide from fish (tilapia) skin that induces significant changes in the intestinal microflora of mice and reduces the Firmicutes/Bacteroidetes ratio, which is linked to obesity. We attempted to verify the anti-obesity effect of selected fish collagen peptides in a high-fat-diet-based obese mouse model. As anticipated, the collagen peptide co-administered with a high-fat diet significantly inhibited the increase in the Firmicutes/Bacteroidetes ratio. It increased specific bacterial taxa, including Clostridium_sensu_stricto_1, Faecalibaculum, Bacteroides, and Streptococcus, known for their anti-obesity effects. Consequently, alterations in the gut microbiota resulted in the activation of metabolic pathways, such as polysaccharide degradation and essential amino acid synthesis, which are associated with obesity inhibition. In addition, collagen peptide also effectively reduced all obesity signs caused by a high-fat diet, such as abdominal fat accumulation, high blood glucose levels, and weight gain. Ingestion of collagen peptides derived from fish skin induced significant changes in the intestinal microflora and is a potential auxiliary therapeutic agent to suppress the onset of obesity.


Assuntos
Bacteroidetes , Firmicutes , Animais , Camundongos , Obesidade/metabolismo , Aumento de Peso , Bactérias , Dieta Hiperlipídica , Peptídeos/farmacologia , Camundongos Endogâmicos C57BL
9.
Biotechnol Bioeng ; 108(3): 621-31, 2011 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-21246509

RESUMO

Although Saccharomyces cerevisiae is capable of fermenting galactose into ethanol, ethanol yield and productivity from galactose are significantly lower than those from glucose. An inverse metabolic engineering approach was undertaken to improve ethanol yield and productivity from galactose in S. cerevisiae. A genome-wide perturbation library was introduced into S. cerevisiae, and then fast galactose-fermenting transformants were screened using three different enrichment methods. The characterization of genetic perturbations in the isolated transformants revealed three target genes whose overexpression elicited enhanced galactose utilization. One confirmatory (SEC53 coding for phosphomannomutase) and two novel targets (SNR84 coding for a small nuclear RNA and a truncated form of TUP1 coding for a general repressor of transcription) were identified as overexpression targets that potentially improve galactose fermentation. Beneficial effects of overexpression of SEC53 may be similar to the mechanisms exerted by overexpression of PGM2 coding for phosphoglucomutase. While the mechanism is largely unknown, overexpression of SNR84, improved both growth and ethanol production from galactose. The most remarkable improvement of galactose fermentation was achieved by overexpression of the truncated TUP1 (tTUP1) gene, resulting in unrivalled galactose fermentation capability, that is 250% higher in both galactose consumption rate and ethanol productivity compared to the control strain. Moreover, the overexpression of tTUP1 significantly shortened lag periods that occurs when substrate is changed from glucose to galactose. Based on these results we proposed a hypothesis that the mutant Tup1 without C-terminal repression domain might bring in earlier and higher expression of GAL genes through partial alleviation of glucose repression. mRNA levels of GAL genes (GAL1, GAL4, and GAL80) indeed increased upon overexpression of tTUP. The results presented in this study illustrate that alteration of global regulatory networks through overexpression of the identified targets (SNR84 and tTUP1) is as effective as overexpression of a rate limiting metabolic gene (PGM2) in the galactose assimilation pathway for efficient galactose fermentation in S. cerevisiae. In addition, these results will be industrially useful in the biofuels area as galactose is one of the abundant sugars in marine plant biomass such as red seaweed as well as cheese whey and molasses.


Assuntos
Etanol/metabolismo , Galactose/metabolismo , Regulação Fúngica da Expressão Gênica , Engenharia Genética , Redes e Vias Metabólicas/genética , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Fermentação , Expressão Gênica , Proteínas Nucleares/biossíntese , RNA Nuclear Pequeno/biossíntese , Proteínas Repressoras/biossíntese , Proteínas de Saccharomyces cerevisiae/biossíntese
10.
Foods ; 10(9)2021 Sep 17.
Artigo em Inglês | MEDLINE | ID: mdl-34574320

RESUMO

ε-Polylysine (ε-PL) is a safe food additive that is used in the food industry globally. This study evaluated the antimicrobial and antibiofilm activity of antibacterial peptides (ε-PL) against food poisoning pathogens detected in chicken (Salmonella Enteritidis, Listeria monocytogenes, and Escherichia coli). The results showed that minimum inhibitory concentrations (MICs) ranged between 0.031-1.0 mg/mL, although most bacterial groups (75%) showed MICs of 1.0 mg/mL. The reduction in the cell viability of pathogens due to ε-PL depended on the time and concentration, and 1/2 × MIC of ε-PL killed 99.99% of pathogens after 10 h of incubation. To confirm biofilm inhibition and degradation effects, crystal violet assay and confocal laser scanning microscopy (CLSM) were used. The biofilm formation rates of four bacterial groups (Salmonella, Listeria, E. coli, and multi-species bacteria) were 10.36%, 9.10%, 17.44%, and 21.37% at 1/2 × MIC of ε-PL, respectively. Additionally, when observed under a CLSM, ε-PL was found to induce biofilm destruction and bacterial cytotoxicity. These results demonstrated that ε-PL has the potential to be used as an antibiotic and antibiofilm material for chicken meat processing.

11.
Appl Environ Microbiol ; 76(18): 6307-9, 2010 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-20675450

RESUMO

A point mutation (E115K) resulting in slower growth of Escherichia coli DH5alpha and XL1-Blue in minimal media was identified in the purB gene, coding for adenylosuccinate lyase (ASL), through complementation with an E. coli K-12 genomic library and serial subcultures. Chromosomal modification reversing the mutation to the wild type restored growth phenotypes in minimal media.


Assuntos
Adenilossuccinato Liase/genética , Escherichia coli/crescimento & desenvolvimento , Escherichia coli/genética , Fenótipo , Meios de Cultura , Teste de Complementação Genética , Fases de Leitura Aberta/genética , Mutação Puntual/genética
12.
Microorganisms ; 8(2)2020 Feb 18.
Artigo em Inglês | MEDLINE | ID: mdl-32085437

RESUMO

Yeasts are very useful microorganisms that are used in many industrial fermentation processes such as food and alcohol production. Microbial contamination of such processes is inevitable, since most of the fermentation substrates are not sterile. Contamination can cause a reduction of the final product concentration and render industrial yeast strains unable to be reused. Alternative approaches to controlling contamination, including the use of antibiotics, have been developed and proposed as solutions. However, more efficient and industry-friendly approaches are needed for use in industrial applications. This review covers: (i) general information about industrial uses of yeast fermentation, (ii) microbial contamination and its effects on yeast fermentation, and (iii) currently used and suggested approaches/strategies for controlling microbial contamination at the industrial and/or laboratory scale.

13.
J Microbiol ; 52(5): 399-406, 2014 May.
Artigo em Inglês | MEDLINE | ID: mdl-24810319

RESUMO

The focus of this study was the cloning, expression, and characterization of recombinant ginsenoside hydrolyzing ß-glucosidase from Arthrobacter chlorophenolicus with an ultimate objective to more efficiently bio-transform ginsenosides. The gene bglAch, consisting of 1,260 bp (419 amino acid residues) was cloned and the recombinant enzyme, overexpressed in Escherichia coli BL21 (DE3), was characterized. The GST-fused BglAch was purified using GST·Bind agarose resin and characterized. Under optimal conditions (pH 6.0 and 37°C) BglAch hydrolyzed the outer glucose and arabinopyranose moieties of ginsenosides Rb1 and Rb2 at the C20 position of the aglycone into ginsenoside Rd. This was followed by hydrolysis into F2 of the outer glucose moiety of ginsenoside Rd at the C3 position of the aglycone. Additionally, BglAch more slowly transformed Rc to F2 via C-Mc1 (compared to hydrolysis of Rb1 or Rb2). These results indicate that the recombinant BglAch could be useful for the production of ginsenoside F2 for use in the pharmaceutical and cosmetic industries.


Assuntos
Arthrobacter/enzimologia , Ginsenosídeos/metabolismo , beta-Glucosidase/metabolismo , Arthrobacter/genética , Biotransformação , Cromatografia de Afinidade , Clonagem Molecular , Escherichia coli/genética , Escherichia coli/metabolismo , Expressão Gênica , Concentração de Íons de Hidrogênio , Hidrólise , Cinética , Proteínas Recombinantes/genética , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/metabolismo , Temperatura , beta-Glucosidase/genética , beta-Glucosidase/isolamento & purificação
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA