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1.
Food Funct ; 2024 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-38752307

RESUMO

Phyllanthus emblica Linn. (PE) fresh fruits contain high concentrations of polyphenolics, of which free and bound phenolics are rich in biological activities. In this study, the inhibitory activity and mechanism of PEFP and PEBP on α-glucosidase (α-GLU) were investigated using spectroscopic techniques, kinetic analysis, and molecular docking. The results showed that 13 PEFP and 12 PEBP were identified by UPLC-MS/MS analysis, and Bis-HHDP-hexose and castalagin (vesgalagin) were found for the first time in PE fresh fruits. Kinetic analysis of enzyme inhibition showed that a mixture of free and bound phenolics inhibited α-GLU, and the effect of the conformational relationship of PEFP and PEBP with α-GLU on hypoglycemia was further explored by fluorescence quenching, circular dichroism (CD) spectroscopy, and molecular docking analysis. The findings demonstrated the inhibitory activity and mechanism of free and bound phenolics on α-GLU and provided a theoretical basis for PE polyphenolics as α-GLU inhibitors for hypoglycemia.

2.
Foods ; 13(7)2024 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-38611312

RESUMO

This study investigates the impact of urea and ß-GP on the growth of Streptococcus thermophilus S-3, a bacterium commonly used in industrial fermentation processes. Through a series of growth experiments, transcriptome, metabolome, and omics-based analyses, the research demonstrates that both urea and ß-GP can enhance the biomass of S. thermophilus, with urea showing a more significant effect. The optimal urea concentration for growth was determined to be 3 g/L in M17 medium. The study also highlights the metabolic pathways influenced by urea and ß-GP, particularly the galactose metabolism pathway, which is crucial for cell growth when lactose is the substrate. The integration of omics data into the genome-scale metabolic model of S. thermophilus, iCH502, allowed for a more accurate prediction of metabolic fluxes and growth rates. The study concludes that urea can serve as a viable substitute for ß-GP in the cultivation of S. thermophilus, offering potential cost and efficiency benefits in industrial fermentation processes. The findings are supported by validation experiments with 11 additional strains of S. thermophilus, which showed increased biomass in UM17 medium.

3.
Foods ; 13(6)2024 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-38540885

RESUMO

Ligilactobacillus salivarius (basonym: Lactobacillus salivarius, L. salivarius) is a type of lactic acid bacteria (LAB) commonly found in the oropharyngeal-gastrointestinal tract (OGT). It has gained significant attention due to its probiotic and functional properties as well as its various health-promoting roles. L. salivarius strains exhibit strong resistance and adhesion in the OGT along with outstanding antioxidant and antimicrobial properties. Additionally, numerous L. salivarius strains have the ability to produce bacteriocins with antagonistic activity. These probiotic characteristics of L. salivarius indicate its remarkable potential in promoting favorable effects on human health. It has also been observed that L. salivarius has a positive effect on the composition of intestinal microbiota, thereby improving the metabolic profiling of intestinal microbiota, promoting a healthy and balanced internal environment. In recent years, multi-omics technologies such as genomics, transcriptomics, proteomics and metabolomics have been employed to gain a deeper understanding of the roles and mechanisms of L. salivarius associated with its functional properties. This review aims to provide an overview of the probiotic characteristics of L. salivarius, containing its specific interactions with the host microflora, as well as insights from omics studies.

4.
ACS Synth Biol ; 13(4): 1365-1372, 2024 Apr 19.
Artigo em Inglês | MEDLINE | ID: mdl-38518262

RESUMO

Lactococcus cremoris (homotypic synonym: Lactococcus lactis) is receiving increasing attention as a prominent vehicle for the delivery of live vaccines. This can hardly be achieved without developing tools for the genetic manipulation of L. cremoris, and the paucity of studies on L. cremoris endogenous promoters has attracted our attention. Here, we report the discovery and characterization of 29 candidate promoters identified from L. cremoris subsp. cremoris NZ9000 by RNA sequencing analysis. Furthermore, 18 possible constitutive promoters were obtained by RT-qPCR screening from these 29 candidate promoters. Then, these 18 promoters were cloned and characterized by a reporter gene, gusA, encoding ß-glucuronidase. Eventually, eight endogenous constitutive promoters of L. cremoris were obtained, which can be applied to genetic manipulation of lactic acid bacteria.


Assuntos
Lactococcus lactis , Lactococcus , Lactococcus lactis/genética , Lactococcus lactis/metabolismo , Regiões Promotoras Genéticas/genética , Genes Reporter/genética , Expressão Gênica
5.
Food Funct ; 15(5): 2563-2576, 2024 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-38353040

RESUMO

In this work, a zein-tamarind seed polysaccharide (TSP) co-delivery system was fabricated using an anti-solvent precipitation method. The formation mechanism, characterization, and effect on alleviating colitis and gut microbiota dysbiosis in mice of zein-TSP-curcumin (Z/T-Cur) nanocomplexes were investigated. Hydrogen bonding and the hydrophobic effect played a key role in the formation of Z/T-Cur nanocomplexes, and the interactions were spontaneous and driven by enthalpy. The encapsulation efficiency, loading capacity, and bioavailability increased from 60.8% (Zein-Cur) to 91.7% (Z/T-Cur1:1), from 6.1% (Zein-Cur) to 18.3% (Z/T-Cur1:1), and from 4.7% (Zein-Cur) to 20.0% (Z/T-Cur1:1), respectively. The Z/T-Cur significantly alleviated colitis symptoms in DSS-treated mice. Additionally, the prepared nanocomplexes rebalanced the gut microbiota composition of colitis mice by increasing the abundance of Akkermansia. Odoribacter and Monoglobus were rich in the Z-T-Cur treatment group, and Turicibacter and Bifidobacterium were rich in the zein-TSP treatment group. This study demonstrated that the TSP could be helpful in the targeted drug delivery system.


Assuntos
Colite , Curcumina , Microbioma Gastrointestinal , Nanopartículas , Tamarindus , Zeína , Animais , Camundongos , Curcumina/química , Zeína/química , Nanopartículas/química , Disbiose/tratamento farmacológico , Polissacarídeos , Colite/induzido quimicamente , Colite/tratamento farmacológico , Tamanho da Partícula
6.
J Sci Food Agric ; 104(3): 1458-1469, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37814322

RESUMO

BACKGROUND: Streptococcus thermophilus is an important strain widely used in dairy fermentation, with distinct urea metabolism characteristics compared to other lactic acid bacteria. The conversion of urea by S. thermophilus has been shown to affect the flavor and acidification characteristics of milk. Additionally, urea metabolism has been found to significantly increase the number of cells and reduce cell damage under acidic pH conditions, resulting in higher activity. However, the physiological role of urea metabolism in S. thermophilus has not been fully evaluated. A deep understanding of this metabolic feature is of great significance for its production and application. Genome-scale metabolic network models (GEMs) are effective tools for investigating the metabolic network of organisms using computational biology methods. Constructing an organism-specific GEM can assist us in comprehending its characteristic metabolism at a systemic level. RESULTS: In the present study, we reconstructed a high-quality GEM of S. thermophilus S-3 (iCH492), which contains 492 genes, 608 metabolites and 642 reactions. Growth phenotyping experiments were employed to validate the model both qualitatively and quantitatively, yielding satisfactory predictive accuracy (95.83%), sensitivity (93.33%) and specificity (100%). Subsequently, a systematic evaluation of urea metabolism in S. thermophilus was performed using iCH492. The results showed that urea metabolism reduces intracellular hydrogen ions and creates membrane potential by producing and transporting ammonium ions. This activation of glycolytic fluxes and ATP synthase produces more ATP for biomass synthesis. The regulation of fluxes of reactions involving NAD(P)H by urea metabolism improves redox balance. CONCLUSION: Model iCH492 represents the most comprehensive knowledge-base of S. thermophilus to date, serving as a potent tool. The evaluation of urea metabolism led to novel insights regarding the role of urease. © 2023 Society of Chemical Industry.


Assuntos
Redes e Vias Metabólicas , Streptococcus thermophilus , Animais , Streptococcus thermophilus/genética , Streptococcus thermophilus/metabolismo , Fermentação , Leite/química , Ureia/metabolismo , Trifosfato de Adenosina/análise
7.
J Sci Food Agric ; 104(2): 1200-1206, 2024 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-37647419

RESUMO

BACKGROUND: The two essential editing elements in the clustered regularly interspaced short palindromic repeats (CRISPR) editing system are promoter and single-guide RNA (sgRNA), the latter of which determines whether Cas protein can precisely target a specific location to edit the targeted gene. Therefore, the selection of sgRNA is crucial to the efficiency of the CRISPR editing system. Various online prediction tools for sgRNA are currently available. These tools can predict all possible sgRNAs of the targeted gene and rank sgRNAs according to certain scoring criteria according to the demands of the user. RESULTS: We designed sgRNAs for Lactococcus lactis NZ9000 LLNZ_RS02020 (ldh) and LLNZ_RS10925 (upp) individually using online prediction software - CRISPOR - and successfully constructed a series of knockout strains to allow comparison of the knockout efficiency of each sgRNA and analyze the differences between software predictions and actual experimental results. CONCLUSION: Our experimental results showed that the actual editing efficiency of the screened sgRNAs did not match the predicted results - a phenomenon that suggests that established findings from eukaryotic studies are not universally applicable to prokaryotes. Software prediction can still be used as a tool for the initial screening of sgRNAs before further selection of suitable sgRNAs through experimental experience. © 2023 Society of Chemical Industry.


Assuntos
Edição de Genes , Lactococcus lactis , Edição de Genes/métodos , Sistemas CRISPR-Cas , RNA Guia de Sistemas CRISPR-Cas , Lactococcus lactis/genética , Software
8.
J Agric Food Chem ; 71(24): 9337-9348, 2023 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-37288995

RESUMO

Western diet is thought to increase susceptibility to inflammatory bowel disease (IBD), and probiotics are a potential therapeutic agent for IBD. This study revealed the effects of Lactobacillus plantarum AR113 and L. plantarum AR113Δbsh1 on a dextran sulfate sodium (DSS)-induced colitis mouse model under the Western diet (WD). After four weeks of WD and low-sugar and low-fat diet (LD) intervention, induction with 3% DSS, and intragastric administration of probiotics, we found that L. plantarum AR113 could regulate blood glucose and lipid levels and have a certain protective effect on hepatocytes. Our results suggested that the L. plantarum AR113 alleviated DSS-induced colitis under the Western diet by improving dyslipidemia, repairing intestinal barrier dysfunction, and inhibiting the TLR4/Myd88/TRAF-6/NF-κB inflammatory pathway. However, these changes were not demonstrated in the L. plantarum AR113Δbsh1, and therefore, we reasoned that the presence of bsh1 may play a crucial role in the L. plantarum AR113 exerting its anti-inflammatory function. The relationship between bile salt hydrolase (BSH) and colitis was worthy of further exploration.


Assuntos
Colite , Doenças Inflamatórias Intestinais , Lactobacillus plantarum , Probióticos , Animais , Camundongos , Anti-Inflamatórios , Colite/induzido quimicamente , Colite/genética , Colite/terapia , Sulfato de Dextrana/efeitos adversos , Dieta Ocidental/efeitos adversos , Modelos Animais de Doenças , Doenças Inflamatórias Intestinais/microbiologia , Lactobacillus plantarum/genética , Lactobacillus plantarum/metabolismo
9.
Microb Cell Fact ; 22(1): 112, 2023 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-37308875

RESUMO

Bifidobacteria are representative intestinal probiotics that have extremely high application value in the food and medical fields. However, the lack of molecular biology tools limits the research on functional genes and mechanisms of bifidobacteria. The application of an accurate and efficient CRISPR system to genome engineering can fill the gap in efficient genetic tools for bifidobacteria. In this study, CRISPR system of B. animalis AR668 was established, which successfully knocked out gene 0348 and gene 0208. The influence of different homology arms and fragments on the knockout effect of the system was explored. In addition, the inducible plasmid curing system of bifidobacteria was innovatively established. This study contributes to the genetic modification and functional mechanism analysis of bifidobacteria.


Assuntos
Bifidobacterium animalis , Probióticos , Sistemas CRISPR-Cas , Bifidobacterium , Edição de Genes
10.
iScience ; 26(3): 106196, 2023 Mar 17.
Artigo em Inglês | MEDLINE | ID: mdl-36895642

RESUMO

Bile salt hydrolases are thought to be the gatekeepers of bile acid metabolism. To study the role of BSH in colitis, we investigated the ameliorative effects of different BSH-knockout strains of Lactiplantibacillus plantarum AR113. The results showed that L. plantarum Δbsh 1 and Δbsh 3 treatments did not improve body weight and alleviate the hyperactivated myeloperoxidase activity to the DSS group. However, the findings for L. plantarum AR113, L. plantarum Δbsh 2 and Δbsh 4 treatments were completely opposite. The double and triple bsh knockout strains further confirmed that BSH 1 and BSH 3 are critical for the ameliorative effects of L. plantarum AR113. In addition, L. plantarum Δbsh 1 and Δbsh 3 did not significantly inhibit the increase in pro-inflammatory cytokines or the decrease in an anti-inflammatory cytokine. These results suggest that BSH 1 and BSH 3 in L. plantarum play important roles in alleviating enteritis symptoms.

11.
J Nutr ; 153(4): 924-939, 2023 04.
Artigo em Inglês | MEDLINE | ID: mdl-36806451

RESUMO

Long-term exposure to adverse life events that provoke acute or chronic psychological stress (hereinafter "stress") can negatively affect physical health and even increase susceptibility to psychological illnesses, such as anxiety and depression. As a part of the hypothalamic-pituitary-adrenal axis, corticotropin-releasing factor (CRF) released from the hypothalamus is primarily responsible for the stress response. Typically, CRF disrupts the gastrointestinal system and leads to gut microbiota dysbiosis, thereby increasing risk of functional gastrointestinal diseases, such as irritable bowel syndrome. Furthermore, CRF increases oxidative damage to the colon and triggers immune responses involving mast cells, neutrophils, and monocytes. CRF even affects the differentiation of intestinal stem cells (ISCs), causing enterochromaffin cells to secrete excessive amounts of 5-hydroxytryptamine (5-HT). Therefore, stress is often accompanied by damage to the intestinal epithelial barrier function, followed by increased intestinal permeability and bacterial translocation. There are multi-network interactions between the gut microbiota and stress, and gut microbiota may relieve the effects of stress on the body. Dietary intake of probiotics can provide energy for ISCs through glycolysis, thereby alleviating the disruption to homeostasis caused by stress, and it significantly bolsters the intestinal barrier, alleviates intestinal inflammation, and maintains endocrine homeostasis. Gut microbiota also directly affect the synthesis of hormones and neurotransmitters, such as CRF, 5-HT, dopamine, and norepinephrine. Moreover, the Mediterranean diet enhances the stress resistance to some extent by regulating the intestinal flora. This article reviews recent research on how stress damages the gut and microbiota, how the gut microbiota can improve gut health by modulating injury due to stress, and how the diet relieves stress injury by interfering with intestinal microflora. This review gives insight into the potential role of the gut and its microbiota in relieving the effects of stress via the gut-brain axis.


Assuntos
Hormônio Liberador da Corticotropina , Sistema Hipotálamo-Hipofisário , Hormônio Liberador da Corticotropina/metabolismo , Sistema Hipotálamo-Hipofisário/metabolismo , Sistema Hipotálamo-Hipofisário/microbiologia , Serotonina , Sistema Hipófise-Suprarrenal/metabolismo , Estresse Psicológico , Homeostase
12.
J Sci Food Agric ; 103(2): 506-513, 2023 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-36468615

RESUMO

BACKGROUND: Probiotic lactic acid bacterium Lactiplantibacillus plantarum is widely used in the dairy and other fermented food industries. L. plantarum AR113 harbors a C30 carotenoid operon crtNM based on genomic analysis, but the yield of C30 carotenoid is only 8.1 µg g-1 DCW. RESULTS: To improve the productivity of C30 carotenoid, crtNM from L. plantarum AR113 was cloned and reconstructed in Escherichia coli BL21(DE3). The proteins crtN and crtM were successfully expressed based on a sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis, and the carotenoid was detected using high-performance liquid chromatography (HPLC) and liquid chromatography-mass spectrometry (LC-MS). In comparison with the constitutive promoter P44 , the use of the inducible T7 promoter significantly increased the carotenoid content in E. coli. The fermentation conditions were also optimized with induction by 0.5 mmol/L IPTG at 20 °C for 7 h. The yield of C30 carotenoid reached 154.5 µg g-1 DCW, which was 18-fold higher than that of L. plantarum AR113. The 2,2-diphenyl-1-picryl (DPPH) and 2,2'-azino-bis (3-ethylbenzothiazoline-6sulfonic acid (ABTS) radical scavenging capacity of C30 carotenoids synthesized by heterologous expression in E. coli was also higher than that of the antioxidant food additive butylated hydroxytoluene. CONCLUSIONS: Our findings suggest that E. coli has strong potential as a basic chassis for the production of C30 carotenoids from Lactiplantibacillus with high antioxidant activity. © 2022 Society of Chemical Industry.


Assuntos
Carotenoides , Escherichia coli , Escherichia coli/genética , Antioxidantes , Hidroxitolueno Butilado , Eletroforese em Gel de Poliacrilamida , Aditivos Alimentares
13.
Food Res Int ; 162(Pt B): 112094, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-36461338

RESUMO

As a thickening or stabilizing agent, exopolysaccharide (EPS) can significantly enhance food texture. However, the conventional analytical and screening methods of EPS have been unable to meet the current needs of industrial production, owing to low efficiency and heavy time-consumption. A simple and rapid qualitative/quantitative method is needed to accelerate the selection of high EPS-producing strains. Here, a high-throughput screening (HTS) program for EPS production was established in S. thermophilus by combining Congo red agar method (CRA, primary screening) and microplate colorimetric assay (MPC, secondary screening). The correlation coefficient (R2) between CRA/MPC and the phenol-sulfuric acid assay (a classical EPS quantification method) were 0.779 and 0.862, respectively, suggesting the feasibility of this HTS method. A mutant library (>300 colonies) of S. thermophilus was constructed using ribosome engineering strategy, and EPS-producing mutants with the titer from 50 mg/L to 200 mg/L were rapidly obtained by our developed HTS method, confirming that the HTS method is simple and efficient for the isolation of EPS-producing S. thermophilus. Taken together, this HTS method was developed for rapidly screening of EPS-producing S. thermophilus, which could be a valuable tool not only for the rapid detection of EPS production capabilities, but also for the screening of strain libraries from genetic engineering with desirable characteristics.


Assuntos
Vermelho Congo , Ensaios de Triagem em Larga Escala , Streptococcus thermophilus , Bioensaio , Ágar
14.
Foods ; 11(16)2022 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-36010472

RESUMO

The probiotics market is one of the fastest growing segments of the food industry as there is growing scientific evidence of the positive health effects of probiotics on consumers. Currently, there are various forms of probiotic products and they can be categorized according to dosage form and the site of action. To increase the effectiveness of probiotic preparations, they need to be specifically designed so they can target different sites, such as the oral, upper respiratory or gastrointestinal tracts. Here we review the characteristics of different dosage forms of probiotics and discuss methods to improve their bioavailability in detail, in the hope that this article will provide a reference for the development of probiotic products.

15.
Curr Microbiol ; 79(9): 280, 2022 Aug 08.
Artigo em Inglês | MEDLINE | ID: mdl-35934757

RESUMO

Lactobacillus salivarius AR809 was isolated from a healthy adult oral cavity with multiple probiotic properties, such as high antimicrobial activity, adhesion to the oral epithelium, resistance to acidic pH, bile, lysozyme, and H2O2. In this study, to investigate the genetic basis on probiotic potential and identify the functional genes in the strain, the complete genome of strain AR809 was sequenced by Illumina and PacBio platforms. Then comparative genome analysis on 11 strains of Lactobacillus salivarius was performed. The complete genome of AR809 consisted of a circular 1,747,224 bp chromosome with 33.00% GC content and four circular plasmids [pA (247,948 bp), pB (27,292 bp), pC (3349 bp), and pD (2898 bp), respectively]. From among the 1866 protein-coding genes, 130 carbohydrate metabolism-related genes, 18 bacteriocin biosynthesis-related genes, 74 environmental stress-related genes, and a series of adhesion-related genes were identified via clusters of orthologous genes, Koyto Encyclopedia of Genes and Genomes, and carbohydrate-active enzymes annotation. The comparative genome analysis indicated that genomic homology between AR809 and CICC23174 was the highest. In conclusion, the present work provided valuable insights into the gene's function prediction and understanding the genetic basis on adapting to host oropharyngeal-gastrointestinal tract in strain AR809.


Assuntos
Ligilactobacillus salivarius , Probióticos , Células Epiteliais , Peróxido de Hidrogênio , Boca
16.
Food Res Int ; 158: 111550, 2022 08.
Artigo em Inglês | MEDLINE | ID: mdl-35840244

RESUMO

Streptococcus thermophilus is an economically prominent starter for common dairy products due to its potential health and nutritional benefits. However, lack of precise genetic manipulation approaches has greatly hampered the industrial application of S. thermophilus.. Herein, we developed an efficient genome editing toolbox (pKLH353) based on CRISPR/nCas9 (Cas9 nickase) in S. thermophilus to seamlessly edit single or multiple genes. A native constitutive promoter library was used to optimize the nCas9 and sgRNA expression with gene deletion efficiencies of 14-60%. The epsA, epsB and epsE were identified as key genes affecting exopolysaccharide (EPS) biosynthesis in S. thermophilus S-3 using the CRISPR/nCas9 toolbox. Moreover, compared to the wild-type, knockout of epsC, epsE or epsG led to a decrease of EPS titer with reducing in its molecular weight (>2.5-fold) and intrinsic viscosity (>19.8-fold). The ratio of monosaccharide composition of the mutants has also changed, suggesting that these eps genes are involved in the chain length synthesis and repeat unit assembly. Taken together, this CRISPR/nCas9 system can serve as a basic toolkit for precise genetic engineering of S. thermophilus and facilitate strain engineering to produce bio-based products.


Assuntos
Edição de Genes , Streptococcus thermophilus , Laticínios , Polissacarídeos Bacterianos/genética , Polissacarídeos Bacterianos/metabolismo , Streptococcus thermophilus/genética , Streptococcus thermophilus/metabolismo
17.
Front Microbiol ; 13: 921164, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35875549

RESUMO

Antrodia camphorata is rich in a variety of bioactive ingredients; however, the utilization efficiency of the residue of A. camphorata is low, resulting in serious waste. It is necessary to deeply study the functional components of A. camphorata residues to achieve high-value utilization. In this study, the components, structural characteristics, and functional properties of alkali-extracted dietary fiber extracted from residues of A. camphorata (basswood and dish cultured fruiting body, respectively) were investigated. There were similar components and structural characteristics of ACA-DK (extract from basswood cultured) and ACA-DF (extract from dish cultured). The two alkali-extracted dietary fiber were composed of mainly cellulose and xylan. However, ACA-DK has better adsorption capacities than ACA-DF on lipophilic substances such as oil (12.09 g/g), cholesterol (20.99 mg/g), and bile salts (69.68 mg/g). In vitro immunomodulatory assays stated that ACA-DK had a good effect on promoting the proliferation of RAW 264.7 cells and can activate cell phagocytosis, NO synthesis, and other immune capabilities. The edible fungus A. camphorata is a good source of functional dietary fiber. The alkali-extracted dietary fiber of A. camphorata might be used as a functional ingredient in the medicine and food industry.

18.
J Dairy Sci ; 105(8): 6499-6512, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35691751

RESUMO

Streptococcus thermophilus is used extensively in the dairy industry and has shown great promise as a chassis cell for the biosynthesis of high-value metabolites. However, metabolic engineering in S. thermophilus lacks effective genetic modification tools to modulate gene expression to relieve metabolic burden and maximize the production of desired compounds. Here, we developed a clustered regularly interspaced short palindromic repeats interference (CRISPRi) system for efficient gene transcriptional modulation in S. thermophilus. Our CRISPRi system typically achieved 66 to 98% knockdown of single or multiple gene expression. We used CRISPRi for the biosynthesis of a new exopolysaccharide (EPS) as a paradigm model. Repression of galK at module of uridine diphosphate glucose sugar metabolism and overexpression of epsA and epsE at EPS synthesis module resulted in an approximately 2-fold increase in EPS titer (277 mg/L) when compared with a control strain. This study demonstrated the effectiveness of CRISPRi as a powerful metabolic engineering tool and synthetic biology strategy for S. thermophilus.


Assuntos
Repetições Palindrômicas Curtas Agrupadas e Regularmente Espaçadas , Streptococcus thermophilus , Animais , Repetições Palindrômicas Curtas Agrupadas e Regularmente Espaçadas/genética , Engenharia Metabólica/métodos , Engenharia Metabólica/veterinária , Redes e Vias Metabólicas , Streptococcus thermophilus/genética , Streptococcus thermophilus/metabolismo
19.
Front Nutr ; 9: 917043, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35711544

RESUMO

Probiotics have attracted much attention due to their ability to modulate host intestinal microbe, participate in nutrient metabolism or immunomodulatory. Both inflammatory bowel disease (IBD) and bowel cancer are digestive system disease, which have become a global public health problem due to their unclear etiology, difficult to cure, and repeated attacks. Disturbed gut microbiota and abnormal lipid metabolism would increase the risk of intestinal inflammation. However, the link between lipid metabolism, probiotics, and IBD is unclear. In this review, we found that different lipids and their derivatives have different effects on IBD and gut microbes. ω-3 polyunsaturated fatty acids (PUFAs) docosahexaenoic acid, eicosapentaenoic acid, and their derivatives resolvin E1, resolvin D can inhibit oxidative stress and reactive oxygen species activate NFκB and MAPk pathway. While ω-6 PUFAs linoleic acid and arachidonic acid can be derived into leukotrienes and prostaglandins, which will aggravate IBD. Cholesterol can be converted into bile acids to promote lipid absorption and affect microbial survival and colonization. At the same time, it is affected by microbial bile salt hydrolase to regulate blood lipids. Low denstiy lipoprotein (LDL) is easily converted into oxidized LDL, thereby promoting inflammation, while high denstiy lipoprotein (HDL) has the opposite effect. Probiotics compete with intestinal microorganisms for nutrients or ecological sites and thus affect the structure of intestinal microbiota. Moreover, microbial short chain fatty acids, bile salt hydrolase, superoxide dismutase, glutathione, etc. can affect lipid metabolism and IBD. In conclusion, probiotics are directly or indirectly involved in lipids metabolism and their impact on IBD, which provides the possibility to explore the role of probiotics in improving gut health.

20.
Food Res Int ; 157: 111382, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-35761638

RESUMO

Lactiplantibacillus plantarum is an important member of the probiotic family and colonization of the host intestinal is essential for its continued probiotic function. The mechanism of L. plantarum intestinal colonization has not been elucidated until now, an important reason being that the colonization process is influenced by a number of factors. In this study, to confirm the influences of adhesion ability and host intestinal environment on L. plantarum intestinal colonization, knockouts of L. plantarum AR113 mucin genes were constructed using CRISPR/Cas9 gene editing technology, and polyethylene glycol was used to reduce the intestinal flora abundance. The knockout of L. plantarum AR113 mucin genes barely altered the strain's tolerance to acid and bile salts. Notably, the adhesion number of AR113ΔLp_1431ΔLp_2233ΔLp_2792 to HT-29 cells was reduced from 175 to 114 per 100 cells. Through in vivo colonization experiments, an increase in the fluorescence intensity of AR113 and AR113ΔLp_1431&2233&2792 was detected the day after the mice were fed, while the deletion of Lp_1431, Lp_2233 and Lp_2792 genes reduced the intestinal tract colonization time from 14 to 11 days. Both AR113 and AR113ΔLp_1431ΔLp_2233ΔLp_2792 were reproduced in the intestine by labeling with 5-(6)-carboxyfluorescein diacetate N-succinimidyl ester. The results showed that the change in fluorescence intensity was closely dependent on the number of adhesions. Finally, compared to the control group, the prolonged intestinal colonization time of AR113ΔLp_1431ΔLp_2233ΔLp_2792 increased mice intestinal flora abundance, with distributions in the duodenum, jejunum, ileum and colon. Collectively, both the intestinal environment and the adhesion ability of L. plantarum AR113 affected intestinal colonization, and the host's intestinal genetic background may be a key factor in the intestinal colonization of L. plantarum.


Assuntos
Intestinos , Lactobacillus plantarum , Probióticos , Animais , Intestinos/microbiologia , Lactobacillus plantarum/genética , Lactobacillus plantarum/fisiologia , Camundongos , Mucinas/genética
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