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1.
J Agric Food Chem ; 72(25): 14302-14314, 2024 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-38865607

RESUMO

In this work, lactoferrin (LF)-chitosan (CS) composite hydrogels with good loading capacity of thermosensitive bioactive substances were successfully obtained by microbial transglutaminase (MTG)-induced cross-linking. We evaluated the rheological, textural, and microstructural characteristics of the composite hydrogels under different conditions. The results demonstrated that the concentrations of LF and CS as well as the amount of MTG could regulate the textural properties, rheological properties, and water holding capability. The results of FTIR and fluorescence spectroscopy indicated that the main interactions within the composite gel were hydrogen and isopeptide bonds. Additionally, in vitro digestion simulation results verified that riboflavin kept stable in stomach due to the protection of LF-CS composite hydrogels and was released in small intestine. These results suggested that thermosensitive bioactive substance could be encapsulated and delivered by the LF-CS composite hydrogel, which could be applied in lots of potential applications in functional food as a new material.


Assuntos
Quitosana , Hidrogéis , Lactoferrina , Reologia , Transglutaminases , Transglutaminases/química , Transglutaminases/metabolismo , Hidrogéis/química , Quitosana/química , Lactoferrina/química , Proteínas de Bactérias/química , Proteínas de Bactérias/metabolismo , Sistemas de Liberação de Medicamentos , Portadores de Fármacos/química , Digestão
2.
Bioresour Technol ; 406: 131035, 2024 Jun 24.
Artigo em Inglês | MEDLINE | ID: mdl-38925409

RESUMO

Yarrowia lipolytica was successfully engineered to synthesize erythritol from crude glycerol, a cheap by-product of biodiesel production, but the yield remained low. Here, a biosensor-guided adaptive evolution screening platform was constructed to obtain mutant strains which could efficiently utilize crude glycerol to produce erythritol. Erythrose reductase D46A (M1) was identified as a key mutant through whole-genome sequencing of the strain G12, which exhibited higher catalytic activity (1.6-fold of the wild-type). M1 was further modified to obtain a combinatorial mutant with 4.1-fold enhancement of catalytic activity. Finally, the metabolic network was reconfigured to redirect carbon fluxes toward erythritol synthesis. The erythritol titer of the engineered strain G31 reached 220.5 g/L with a productivity of 1.8 g/L/h in a 5-L bioreactor. The study provides valuable guidance for biosensor-based ultra-high-throughput screening strategies in Y. lipolytica, as well as presenting a new paradigm for the sustainable valorization of crude glycerol.

3.
Int J Biol Macromol ; 273(Pt 1): 132831, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38825287

RESUMO

17α-Hydroxyprogesterone (17α-OH-PROG) is an important intermediate with a wide range of applications in the pharmaceutical industry. Strategies based on efficient electron transfer and cofactor regeneration were used for the production of 17α-OH-PROG. Here, CYP260A1, Fpr and Adx were expressed using a double plasmid system, resulting in higher biotransformation efficiency. Further optimization of reaction conditions and addition of polymyxin B increased the production of 17α-OH-PROG from 12.52 mg/L to 102.37 mg/L after 12 h of biotransformation. To avoid the addition of external 5-aminolevulinic acid (ALA) as a heme precursor for the P450 enzyme, a modified C5 pathway was introduced into the engineered strain, further reducing the overall process cost. The resulting whole-cell biocatalyst achieved the highest biotransformation yield of 17α-OH-PROG reported to date, offering a promising strategy for commercial application of P450 enzymes in industrial production of hydroxylated intermediates.


Assuntos
Ácido Aminolevulínico , Sistema Enzimático do Citocromo P-450 , Sistema Enzimático do Citocromo P-450/metabolismo , Sistema Enzimático do Citocromo P-450/genética , Ácido Aminolevulínico/metabolismo , Transporte de Elétrons , Biocatálise , Biotransformação
4.
J Hazard Mater ; 474: 134779, 2024 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-38850935

RESUMO

Bisphenol A (BPA), an endocrine disrupter with estrogen activity, can infiltrate animal and human bodies through the food chain. Enzymatic degradation of BPA holds promise as an environmentally friendly approach while it is limited due to lower stability and recycling challenges. In this study, laccase from Bacillus pumilus TCCC 11568 was expressed in Pichia pastoris (fLAC). The optimal catalytic conditions for fLAC were at pH 6.0 and 80 °C, with a half-life T1/2 of 120 min at 70 °C. fLAC achieved a 46 % degradation rate of BPA, and possible degradation pathways were proposed based on identified products and reported intermediates of BPA degradation. To improve its stability and degradation capacity, a whole-cell biocatalyst (WCB) was developed by displaying LAC (dLAC) on the surface of P. pastoris GS115. The functionally displayed LAC demonstrated enhanced thermostability and pH stability along with an improved BPA degradation ability, achieving a 91 % degradation rate. Additionally, dLAC maintained a degradation rate of over 50 % after the fourth successive cycles. This work provides a powerful catalyst for degrading BPA, which might decontaminate endocrine disruptor-contaminated water through nine possible pathways.


Assuntos
Bacillus pumilus , Compostos Benzidrílicos , Biodegradação Ambiental , Disruptores Endócrinos , Lacase , Fenóis , Compostos Benzidrílicos/metabolismo , Lacase/metabolismo , Lacase/genética , Fenóis/metabolismo , Bacillus pumilus/enzimologia , Bacillus pumilus/genética , Bacillus pumilus/metabolismo , Disruptores Endócrinos/metabolismo , Concentração de Íons de Hidrogênio , Saccharomycetales/metabolismo , Saccharomycetales/genética
5.
Database (Oxford) ; 20242024 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-38865432

RESUMO

Alzheimer's disease (AD) is a universal neurodegenerative disease with the feature of progressive dementia. Currently, there are only seven Food and Drug Administration-approved drugs for the treatment of AD, which merely offer temporary relief from symptom deterioration without reversing the underlying disease process. The identification of inhibitors capable of interacting with proteins associated with AD plays a pivotal role in the development of effective therapeutic interventions. However, a vast number of such inhibitors are dispersed throughout numerous published articles, rendering it inconvenient for researchers to explore potential drug candidates for AD. In light of this, we have manually compiled inhibitors targeting proteins associated with AD and constructed a comprehensive database known as IPAD-DB (Inhibitors of Proteins associated with Alzheimer's Disease Database). The curated inhibitors within this database encompass a diverse range of compounds, including natural compounds, synthetic compounds, drugs, natural extracts and nano-inhibitors. To date, the database has compiled >4800 entries, each representing a correspondent relationship between an inhibitor and its target protein. IPAD-DB offers a user-friendly interface that facilitates browsing, searching and downloading of its records. We firmly believe that IPAD-DB represents a valuable resource for screening potential AD drug candidates and investigating the underlying mechanisms of this debilitating disease. Access to IPAD-DB is freely available at http://www.lamee.cn/ipad-db/ and is compatible with all major web browsers. Database URL: http://www.lamee.cn/ipad-db/.


Assuntos
Doença de Alzheimer , Doença de Alzheimer/tratamento farmacológico , Doença de Alzheimer/metabolismo , Humanos , Bases de Dados de Proteínas , Curadoria de Dados/métodos , Interface Usuário-Computador
6.
J Gen Appl Microbiol ; 2024 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-38897942

RESUMO

In recent years, a convenient phosphatase-coupled sulfotransferase assay method has been proven to be applicable to most sulfotransferases. The central principle of the method is that phosphatase specifically degrades 3'-phosphoadenosine-5'-phosphate (PAP) and leaves 3'-phosphoadenosine-5'-phosphosulfate (PAPS). Our group previously acquired a yeast 3',5'-bisphosphate nucleotidase (YND), which showed a higher catalytic activity for PAP than PAPS and could be a potential phosphatase for the sulfotransferase assay. Here, we obtained a beneficial mutant of YND with markedly improved substrate specificity towards PAP via rational design. Of 9 chosen mutation sites in the active site pocket, the mutation G236D showed the best specificity for PAP. After optimization of the reaction conditions, the mutant YNDG236D displayed a 4.8-fold increase in the catalytic ratio PAP/PAPS compared to the wild-type. We subsequently applied YNDG236D to the assay of human SULT1A1 and SULT1A3 with their known substrate 1-naphthol, indicating that the mutant could be used to evaluate sulfotransferase activity by colorimetry. Analysis of the MD simulation results revealed that the improved substrate specificity of the mutant towards PAP may stem from a more stable protein conformation and the changed flexibility of key residues in the entrance of the substrate tunnel. This research will provide a valuable reference for the development of efficient sulfotransferase activity assays.

7.
Insect Mol Biol ; 2024 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-38898565

RESUMO

Bombyx mori cecropin A (Bmcecropin A) has antibacterial, antiviral, anti-filamentous fungal and tumour cell inhibition activities and is considered a potential succedaneum for antibiotics. We clarified the antibacterial mechanism and structure-activity relationships and then directed the structure-activity optimization of Bmcecropin A. Firstly, we found Bmcecropin A shows a strong binding force and permeability to cell membranes like a detergent; Bmcecropin A could competitively bind to the cell membrane with the cell membrane-specific dye DiI, then damaged the membrane for the access of DiI into the cytoplasm and leading to the leakage of electrolyte and proteins. Secondly, we found Bmcopropin A could also bind to and degrade DNA; furthermore, DNA library polymerase chain reaction (PCR) results indicated that Bmcecropin A inhibited DNA replication by non-specific binding. In addition, we have identified C-terminus amidation and serine-lysine- glycine (SLG) amino acids of Bmcecropin A played critical roles in the membrane damage and DNA degradation. Based on the above results, we designed a mutant of Bmcecropin A (E9 to H, D17 to K, K33 to A), which showed higher antibacterial activity, thermostability and pH stability than ampicillin but no haemolytic activity. Finally, we speculated that Bmcecropin A damaged the cell membrane through a carpet model and drew the schematic diagram of its antibacterial mechanism, based on the antibacterial mechanism and the three-dimensional configuration. These findings yield insights into the mechanism of antimicrobial peptide-pathogen interaction and beneficial for the development of new antibiotics.

8.
J Oral Microbiol ; 16(1): 2372224, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38939048

RESUMO

The diversity and delicate balance of the oral microbiome contribute to oral health, with its disruption leading to oral and systemic diseases. Toothpaste includes elements like traditional additives such as sodium lauryl sulfate (SLS) as well as novel postbiotics derived from probiotics, which are commonly employed for maintaining oral hygiene and a healthy oral cavity. However, the response of the oral microbiota to these treatments remains poorly understood. In this study, we systematically investigated the impact of SLS, and toothpaste containing postbiotics (hereafter, postbiotic toothpaste) across three systems: biofilms, animal models, and clinical populations. SLS was found to kill bacteria in both preformed biofilms (mature biofilms) and developing biofilms (immature biofilms), and disturbed the microbial community structure by increasing the number of pathogenic bacteria. SLS also destroyed periodontal tissue, promoted alveolar bone resorption, and enhanced the extent of inflammatory response level. The postbiotic toothpaste favored bacterial homeostasis and the normal development of the two types of biofilms in vitro, and attenuated periodontitis and gingivitis in vivo via modulation of oral microecology. Importantly, the postbiotic toothpaste mitigated the adverse effects of SLS when used in combination, both in vitro and in vivo. Overall, the findings of this study describe the impact of toothpaste components on oral microflora and stress the necessity for obtaining a comprehensive understanding of oral microbial ecology by considering multiple aspects.

9.
Food Chem ; 453: 139637, 2024 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-38781897

RESUMO

Herein, a novel multifunctional enzyme ß-glucosidase/xylanase/feruloyl esterase (GXF) was constructed by fusion of ß-glucosidase and bifunctional xylanase/feruloyl esterase. The activities of ß-glucosidase, xylanase, feruloyl esterase and acetyl xylan esterase displayed by GXF were 67.18 %, 49.54 %, 38.92 % and 23.54 %, respectively, higher than that of the corresponding single functional enzymes. Moreover, the GXF performed better in enhancing aroma and quality of Longjing tea than the single functional enzymes and their mixtures. After treatment with GXF, the grassy and floral odors of tea infusion were significantly improved. Moreover, GXF treatment could improve concentrations of flavonoid aglycones of myricetin, kaempferol and quercetin by 68.1-, 81.42- and 77.39-fold, respectively. In addition, GXF could accelerate the release of reducing sugars, ferulic acid and xylo-oligosaccharides by 9.48-, 8.25- and 4.11-fold, respectively. This multifunctional enzyme may have potential applications in other fields such as food production and biomass degradation.


Assuntos
Camellia sinensis , Hidrolases de Éster Carboxílico , Chá , beta-Glucosidase , Hidrolases de Éster Carboxílico/química , Hidrolases de Éster Carboxílico/metabolismo , beta-Glucosidase/química , beta-Glucosidase/metabolismo , Camellia sinensis/química , Camellia sinensis/enzimologia , Chá/química , Endo-1,4-beta-Xilanases/química , Endo-1,4-beta-Xilanases/metabolismo , Odorantes/análise
10.
Int J Biol Macromol ; 269(Pt 2): 132166, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38723822

RESUMO

Improving the ability of bacteria to secrete protein is essential for large-scale production of food enzymes. However, due to the lack of effective tracking technology for target proteins, the optimization of the secretory system is facing many problems. In this study, we utilized the split-GFP system to achieve self-assembly into mature GFP in Bacillus amyloliquefaciens and successfully tracked the alkaline protease AprE. The split-GFP system was employed to assess the signal peptidases, a crucial component in the secretory system, and signal peptidase sipA was identified as playing a role in the secretion of AprE. Deletion of sipA resulted in a higher accumulation of the precursor protein of AprE compared to other signal peptidase deletion strains. To explore the mechanism of signal peptidase on signal peptide, molecular docking and calculation of free energy were performed. The action strength of the signal peptidase is determined by its binding affinity with the tripeptides at the C-terminal of the signal peptide. The functions of signal peptides YdbK and NucB rely on sipA, and overexpression of sipA by integrating it into genome of B. amyloliquefaciens increased the activity of extracellular AprE by 19.9 %. These findings provide insights into enhancing the secretion efficiency of chassis strains.


Assuntos
Bacillus amyloliquefaciens , Proteínas de Bactérias , Endopeptidases , Proteínas de Fluorescência Verde , Bacillus amyloliquefaciens/enzimologia , Bacillus amyloliquefaciens/genética , Bacillus amyloliquefaciens/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Proteínas de Bactérias/química , Endopeptidases/metabolismo , Endopeptidases/genética , Endopeptidases/química , Proteínas de Fluorescência Verde/metabolismo , Proteínas de Fluorescência Verde/genética , Simulação de Acoplamento Molecular , Sinais Direcionadores de Proteínas , Proteínas de Membrana , Serina Endopeptidases , Proteínas de Membrana Transportadoras
11.
Bioresour Technol ; 402: 130798, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38705212

RESUMO

Biosensor-based high-throughput screening is efficient for improving industrial microorganisms. There is a severe shortage of human milk oligosaccharides (HMOs) biosensors. This study established a 3-fucosyllactose (3-FL, a kind of HMOs) whole-cell biosensor by coupling cell growth with production. To construct and optimize the biosensor, an Escherichia coli 3-FL producer was engineered by deleting the manA, yihS and manX genes, directing the mannose flux solely to 3-FL synthesis. Then, an α-L-fucosidase was introduced to hydrolyze 3-FL to fucose which was used as the only carbon source for cell growth. Using the biosensor, the 3-FL production of a screened mutant was improved by 25 % to 42.05 ± 1.28 g/L. The productivity reached 1.17 g/L/h, the highest level reported by now. The csrB mutant obtained should be a new clue for the 3-FL overproduction mechanism. In summary, this study provided a novel approach to construct HMOs biosensors for strain improvement.


Assuntos
Técnicas Biossensoriais , Escherichia coli , Trissacarídeos , Técnicas Biossensoriais/métodos , Escherichia coli/metabolismo , Escherichia coli/genética , Trissacarídeos/metabolismo , Ensaios de Triagem em Larga Escala/métodos , Mutação , Humanos , Leite Humano/química , alfa-L-Fucosidase/metabolismo , alfa-L-Fucosidase/genética , Oligossacarídeos
12.
Food Chem ; 454: 139835, 2024 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-38815323

RESUMO

Lactoferrin (LF) with various biological functions demonstrates great application potential. However, its application was restricted by its poor gelation and instability. The aim of this work was to explore the effect of microbial transglutaminase (MTGase) and Tremella fuciformis polysaccharide (TP) on the functional properties of LF. The formation of a self-supporting LF gel could be induced by MTGase through generating covalent crosslinks between the LF protein molecules. Meanwhile, TP was introduced into the gel system to improve the strength of LF-TP composite gels by enhancing non-covalent interactions such as hydrogen bond and electrostatic interactions during gel formation. Additionally, the LF-TP composite gel exhibited outstanding functional characteristics such as gastrointestinal digestive stability and antioxidant property. This work clarified the mechanism on MTGase and TP-mediated modification of lactoferrin, offered a novel strategy to increase the functional characteristics of LF, and enlarged the application range of LF and TP.


Assuntos
Basidiomycota , Alimento Funcional , Lactoferrina , Polissacarídeos , Transglutaminases , Lactoferrina/química , Lactoferrina/metabolismo , Transglutaminases/metabolismo , Transglutaminases/química , Polissacarídeos/química , Polissacarídeos/metabolismo , Basidiomycota/química , Basidiomycota/enzimologia , Basidiomycota/metabolismo , Proteínas Fúngicas/química , Proteínas Fúngicas/metabolismo , Antioxidantes/química , Antioxidantes/metabolismo
13.
Food Chem ; 449: 139147, 2024 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-38581784

RESUMO

Mung bean protein isolate (MBPI) has attracted much attention as an emerging plant protein. However, its application was limited by the poor gelling characteristics. Thus, the effect of sanxan (SAN) on the gelling behavior of MBPI under microbial transglutaminase (MTG)-induced condition were explored in this study. The results demonstrated that SAN remarkably enhanced the storage modulus, water-holding capacity and mechanical strength. Furthermore, SAN changed the microstructure of MBPI gels to become more dense and ordered. The results of zeta potential indicated the electrostatic interactions existed between SAN and MBPI. The incorporation of SAN altered the secondary structure and molecular conformation of MBPI, and hydrophobic interactions and hydrogen bonding were necessary to maintain the network structure. Additionally, in vitro digestion simulation results exhibited that SAN remarkably improved the capability of MBPI gels to deliver bioactive substances. These findings provided a practical strategy to use natural SAN to improve legume protein gels.


Assuntos
Géis , Proteínas de Plantas , Transglutaminases , Vigna , Transglutaminases/química , Transglutaminases/metabolismo , Vigna/química , Géis/química , Proteínas de Plantas/química , Interações Hidrofóbicas e Hidrofílicas , Ligação de Hidrogênio
14.
Foods ; 13(8)2024 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-38672899

RESUMO

Isomaltulose is a novel sweetener and is considered healthier than the common sugars, such as sucrose or glucose. It has been internationally recognized as a safe food product and holds vast potential in pharmaceutical and food industries. Sucrose isomerase is commonly used to produce isomaltulose from the substrate sucrose in vitro and in vivo. However, free cells/enzymes were often mixed with the product, making recycling difficult and leading to a significant increase in production costs. Immobilized cells/enzymes have the following advantages including easy separation from products, high stability, and reusability, which can significantly reduce production costs. They are more suitable than free ones for industrial production. Recently, immobilized cells/enzymes have been encapsulated using composite materials to enhance their mechanical strength and reusability and reduce leakage. This review summarizes the advancements made in immobilized cells/enzymes for isomaltulose production in terms of refining traditional approaches and innovating in materials and methods. Moreover, innovations in immobilized enzyme methods include cross-linked enzyme aggregates, nanoflowers, inclusion bodies, and directed affinity immobilization. Material innovations involve nanomaterials, graphene oxide, and so on. These innovations circumvent challenges like the utilization of toxic cross-linking agents and enzyme leakage encountered in traditional methods, thus contributing to enhanced enzyme stability.

15.
Sci Total Environ ; 927: 172352, 2024 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-38608900

RESUMO

Mulberry cultivation and silkworm rearing hold a prominent position in the agricultural industries of many Asian countries, contributing to economic growth, sustainable development, and cultural heritage preservation. Applying the soil-mulberry-silkworm system (SMSS) to heavy metal (HM)-contaminated areas is significant economically, environmentally, and socially. The ultimate goal of this paper is to review the main research progress of SMSS under HM stress, examining factors affecting its safe utilization and remediation potential for HM-contaminated soils. HM tolerance of mulberry and silkworms relates to their growth stages. Based on the standards for HM contaminants in various mulberry and silkworm products and the bioconcentration factor of HMs at different parts of SMSS, we calculated maximum safe Cd and Pb levels for SMSS application on contaminated lands. Several remediation practices demonstrated mulberry's ability to grow on barren lands, absorb various HMs, while silkworm excreta can adsorb HMs and improve soil fertility. Considering multiple factors influencing HM tolerance and accumulation, we propose a decision model to guide SMSS application in polluted areas. Finally, we discussed the potential of using molecular breeding techniques to screen or develop varieties better suited for HM-contaminated regions. However, actual pollution scenarios are often complex, requiring consideration of multiple factors. More large-scale applications are crucial to enhance the theoretical foundation for applying SMSS in HM pollution risk areas.


Assuntos
Bombyx , Recuperação e Remediação Ambiental , Metais Pesados , Morus , Poluentes do Solo , Metais Pesados/análise , Animais , Poluentes do Solo/análise , Recuperação e Remediação Ambiental/métodos , Solo/química
16.
Int J Biol Macromol ; 264(Pt 2): 130695, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38458278

RESUMO

The fibrillogenesis of amyloid ß-protein (Aß) gradually accumulates to form neurotoxic Aß aggregates in the human brain, which is the direct cause of Alzheimer's disease (AD) related symptoms. There are currently no effective therapies for AD. Brazilin, a natural polyphenol, inhibits Aß fibrillogenesis, disrupts the mature fibrils and alleviates the corresponding cytotoxicity, but it also has the high toxic. Therefore, brazilin-7-2-butenoate (B-7-2-B), a brazilin derivative, was designed and synthesized. B-7-2-B exhibited lower toxicity and stronger inhibitory effect on Aß aggregation than brazilin. B-7-2-B could prevent the formation of Aß fibrils and oligomers, and depolymerize pre-formed aggregates in a dose-dependent manner. Furthermore, B-7-2-B prominently alleviated the cytotoxicity and the oxidative stress induced by Aß aggregates in PC12 cells. The protective impacts of B-7-2-B were further demonstrated by using the Caenorhabditis elegans model, including decreasing the extent of Aß aggregation, improving the motility and sensation disorders. Eventually, B-7-2-B was proven to be no apparent damage to worms. In summarize, it can be concluded that B-7-2-B has the potential as a drug for treating AD.


Assuntos
Doença de Alzheimer , Peptídeos beta-Amiloides , Animais , Ratos , Humanos , Peptídeos beta-Amiloides/toxicidade , Caenorhabditis elegans , Benzopiranos/farmacologia , Células PC12 , Doença de Alzheimer/tratamento farmacológico , Amiloide
17.
Int J Biol Macromol ; 266(Pt 1): 130818, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38479659

RESUMO

Alkaline protease AprE, produced by Bacillus licheniformis 2709 is an important edible hydrolase, which has potential applications in nutrient acquisition and medicine. The expression of AprE is finely regulated by a complex transcriptional regulation system. However, there is little study on transcriptional regulation mechanism of AprE biosynthesis in Bacillus licheniformis, which limits system engineering and further enhancement of AprE. Here, the severely depressed expression of aprE in degU and degS deletion mutants illustrated that the regulator DegU and its phosphorylation played a crucial part in AprE biosynthesis. Further electrophoretic mobility shift assay (EMSA) in vitro indicated that phosphorylated DegU can directly bind to the regulatory region though the DNase I foot-printing experiments failed to observe protected region. The plasmid-mediated overexpression of degU32 (Hy) obviously improved the yield of AprE by 41.6 % compared with the control strain, which demonstrated the importance of phosphorylation state of DegU on the transcription of aprE in vivo. In this study, the putative binding sequence of aprE (5'-TAAAT……AAAAT…….AACAT…TAAAA-3') located upstream -91 to -87 bp, -101 to -97 bp, -195 to -191 bp, -215 to -211 bp of the transcription start site (TSS) in B. licheniformis was computationally identified based on the DNA-binding sites of DegU in Bacillus subtilis. Overall, we systematically investigated the influence of the interplay between phosphorylated DegU and its cognate DNA sequence on expression of aprE, which not only contributes to the further AprE high-production in a genetically modified host in the future, but also significantly increases our understanding of the aprE transcription mechanism.


Assuntos
Bacillus licheniformis , Proteínas de Bactérias , Endopeptidases , Regulação Bacteriana da Expressão Gênica , Proteínas de Membrana Transportadoras , Bacillus licheniformis/genética , Bacillus licheniformis/enzimologia , Bacillus licheniformis/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Endopeptidases/genética , Endopeptidases/metabolismo , Fosforilação , Regiões Promotoras Genéticas
18.
Foods ; 13(6)2024 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-38540881

RESUMO

Ulva polysaccharides present several physiological activities including antiviral, antitumor and anti-plasmodial effects. However, current processing usually results in low yields and high prices, thus lacking commercialization potential. The aim of this study was to develop an efficient method for the extraction of Ulva polysaccharides with high biological activity. The effect of cell wall-degrading enzymes including cellulase, hemicellulase, pectinase and protease on Ulva polysaccharide extraction was studied by statistical mixing design. Using the most effective enzyme preparations as the basic components, the optimal proportions of the enzyme mixture were determined as follows: cellulase 35.3%, pectinase 34.5%, alkaline protease 30.2%, which increased the polysaccharide yield from 6.43% in the absence of enzymes to 26.68%. Subsequently, through response surface analysis, the optimal conditions were determined: enzyme concentration of 1.5%, enzymatic time of 1.1 h, ultrasonic time of 90 min and enzymatic temperature of 60 °C. Under the optimal extraction conditions, the extraction yield of Ulva polysaccharides could be increased to 30.14%. Moreover, extracted polysaccharides exhibit strong antioxidant properties in DPPH, ABTS, hydroxyl radical, superoxide radical and H2O2-induced cellular damage models. This study laid a solid foundation for the use and development of Ulva polysaccharides.

19.
Foods ; 13(6)2024 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-38540913

RESUMO

Hyperuricaemia (HUA) is a disorder of purine metabolism, which manifests itself as an increase in uric acid production and a decrease in uric acid excretion, as well as a change in the structure of the intestinal microbiota. Most of the drugs currently used to treat HUA have significant side effects, and it is essential to find a treatment for HUA that is free of side effects. In this study, a novel strain, Pediococcus acidilactici GQ01, was screened from natural fermented wolfberry. The effects of both live bacteria GQ01 and its heat-killed G1PB postbiotic on HUA were investigated. The results showed that both probiotic GQ01 and G1PB postbiotics could effectively decrease blood uric acid, creatinine, and urea nitrogen levels in the HUA mice model. P. acidilactici GQ01 was more effective in inhibiting ADA activity, while G1PB postbiotics was more effective in inhibiting XOD activity. Meanwhile, GQ01 and G1PB were able to ameliorate liver and kidney tissue injury, upregulate the expression of ABCG2 in kidney and XOD gene in liver, downregulate the protein expression of URAT1 and GLUT9 in kidney, and therefore reduce the value of blood uric acid by decreasing the uric acid reabsorption and increasing the excretion of uric acid. Additionally, both probiotics and postbiotics could regulate the intestinal microbiota structure of HUA mice, so as to bring the dysfunctional intestinal composition back to normal. Furthermore, P. acidilactici GQ01 and G1PB postbiotics can increase the levels of acetic acid, propionic acid, and butyric acid in the intestinal tract, improve the intestinal function, and maintain the healthy homeostatic state of the intestinal tract. In summary, P. acidilactici GQ01 and its G1PB postbiotics may be developed as functional food or drug materials capable of treating HUA.

20.
Food Funct ; 15(8): 4233-4245, 2024 Apr 22.
Artigo em Inglês | MEDLINE | ID: mdl-38517352

RESUMO

The aggregation of ß-amyloid (Aß) peptides to form amyloid plaques is one of the primary hallmarks for Alzheimer's disease (AD). Dietary flavonoid supplements containing hesperetin have an ability to decline the risk of developing AD, but the molecular mechanism is still unclear. In this work, hesperetin, a flavanone abundant in citrus fruits, has been proven to prevent the formation of Aß aggregates and depolymerized preformed fibrils in a concentration-dependent fashion. Hesperetin inhibited the conformational conversion from the natural structure to a ß-sheet-rich conformation. It was found that hesperetin significantly reduced the cytotoxicity and relieved oxidative stress eventuated by Aß aggregates in a concentration-dependent manner. Additionally, the beneficial effects of hesperetin were confirmed in Caenorhabditis elegans, including the inhibition of the formation and deposition of Aß aggregates and extension of their lifespan. Finally, the results of molecular dynamics simulations showed that hesperetin directly interacted with an Aß42 pentamer mainly through strong non-polar and electrostatic interactions, which destroyed the structural stability of the preformed pentamer. To summarize, hesperetin exhibits great potential as a prospective dietary supplement for preventing and improving AD.


Assuntos
Peptídeos beta-Amiloides , Caenorhabditis elegans , Hesperidina , Hesperidina/farmacologia , Hesperidina/química , Peptídeos beta-Amiloides/metabolismo , Peptídeos beta-Amiloides/toxicidade , Peptídeos beta-Amiloides/química , Animais , Caenorhabditis elegans/efeitos dos fármacos , Humanos , Doença de Alzheimer/metabolismo , Doença de Alzheimer/tratamento farmacológico , Doença de Alzheimer/prevenção & controle , Amiloide/metabolismo , Simulação de Dinâmica Molecular , Estresse Oxidativo/efeitos dos fármacos , Agregados Proteicos/efeitos dos fármacos
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