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1.
Foods ; 13(7)2024 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-38611286

RESUMO

Rumexpatientia L. ×Rumextianshanicus A. Los (RRL), known as "protein grass" in China, was recognized as a new food ingredient in 2021. However, the cultivation and product development of RRL are still at an early stage, and no peptide research has been reported. In this study, two novel antioxidant peptides, LKPPF and LPFRP, were purified and identified from RRL and applied to H2O2-induced HepG2 cells to investigate their antioxidant properties. It was shown that 121 peptides were identified by ultrafiltration, gel filtration chromatography, and LC-MS/MS, while computer simulation and molecular docking indicated that LKPPF and LPFRP may have strong antioxidant properties. Both peptides were not cytotoxic to HepG2 cells at low concentrations and promoted cell growth, which effectively reduced the production of intracellular ROS and MDA, and increased cell viability and the enzymatic activities of SOD, GSH-Px, and CAT. Therefore, LKPPF and LPFRP, two peptides, possess strong antioxidant activity, which provides a theoretical basis for their potential as food additives or functional food supplements, but still need to be further investigated through animal models as well as cellular pathways.

2.
Food Res Int ; 185: 114263, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38658068

RESUMO

Investigating technologies to control the allergenicity of seafood is particularly important to safeguard consumer health, but there is currently a dearth of research focused on reducing the allergenicity of clam meat. This study aimed to investigate the effects of high temperature-pressure (HTP) processing times (121 °C, 0.14 MPa; 5, 10, 15, 20 min) on the sensory quality, nutrition, and allergenicity of ready-to-eat clam meat. With the extension of HTP time, the hardness of clam meat gradually decreased, the chewiness decreased initially and then increased, and the meat became tender. HTP processing endowed clam meat with abundant esters and aldehydes. Among all the processing groups, the umami and saltiness were better at 15 min, correlating with the highest overall acceptability. Ready-to-eat clam meat contained high-protein nutritional value. Compared with raw clam meat, the tropomyosin allergenicity of clam meat treated with HTP for 15 and 20 min was significantly reduced by 51.9 % and 56.5 %, respectively (P < 0.05). However, there was no significant difference between these two groups. Appropriate HTP processing time might be an efficient condition to reduce the tropomyosin allergenicity of ready-to-eat clam meat and improve its quality, particularly for the time of 15 min. The results of this study could provide a reliable theoretical basis for the development of hypoallergenic clam foods.


Assuntos
Bivalves , Manipulação de Alimentos , Valor Nutritivo , Bivalves/imunologia , Animais , Humanos , Manipulação de Alimentos/métodos , Tropomiosina/imunologia , Alérgenos/análise , Alérgenos/imunologia , Pressão , Paladar , Alimentos Marinhos , Frutos do Mar , Temperatura Alta , Fatores de Tempo , Adulto , Masculino , Fast Foods , Feminino
3.
Cell Prolif ; 57(3): e13554, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-37767639

RESUMO

'General requirements for the production of extracellular vesicles derived from human stem cells' is the first guideline for stem cells derived extracellular vesicles in China, jointly drafted and agreed upon by experts from the Chinese Society for Stem Cell Research. This standard specifies the general requirements, process requirements, packaging and labelling requirements and storage requirements for preparing extracellular vesicles derived from human stem cells, which is applicable to the research and production of extracellular vesicles derived from stem cells. It was originally released by the China Society for Cell Biology on 30 August 2022. We hope that the publication of this guideline will promote institutional establishment, acceptance and execution of proper protocols, and accelerate the international standardisation of extracellular vesicles derived from human stem cells.


Assuntos
Vesículas Extracelulares , Células-Tronco , Humanos , China
4.
Cell Prolif ; 57(4): e13564, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-37853840

RESUMO

'Human neural stem cells' jointly drafted and agreed upon by experts from the Chinese Society for Stem Cell Research, is the first guideline for human neural stem cells (hNSCs) in China. This standard specifies the technical requirements, test methods, test regulations, instructions for use, labelling requirements, packaging requirements, storage requirements, transportation requirements and waste disposal requirements for hNSCs, which is applicable to the quality control for hNSCs. It was originally released by the China Society for Cell Biology on 30 August 2022. We hope that publication of the guideline will facilitate institutional establishment, acceptance and execution of proper protocols, and accelerate the international standardization of hNSCs for clinical development and therapeutic applications.


Assuntos
Células-Tronco Neurais , Transplante de Células-Tronco , Humanos , Diferenciação Celular , China
5.
Cell Prolif ; 57(4): e13563, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-37881164

RESUMO

Human midbrain dopaminergic progenitors (mDAPs) are one of the most representative cell types in both basic research and clinical applications. However, there are still many challenges for the preparation and quality control of mDAPs, such as the lack of standards. Therefore, the establishment of critical quality attributes and technical specifications for mDAPs is largely needed. "Human midbrain dopaminergic progenitor" jointly drafted and agreed upon by experts from the Chinese Society for Stem Cell Research, is the first guideline for human mDAPs in China. This standard specifies the technical requirements, test methods, inspection rules, instructions for usage, labelling requirements, packaging requirements, storage requirements, transportation requirements and waste disposal requirements for human mDAPs, which is applicable to the quality control for human mDAPs. It was originally released by the China Society for Cell Biology on 30 August 2022. We hope that the publication of this guideline will facilitate the institutional establishment, acceptance and execution of proper protocols, and accelerate the international standardization of human mDAPs for clinical development and therapeutic applications.


Assuntos
Neurônios Dopaminérgicos , Mesencéfalo , Humanos , China , Neurônios Dopaminérgicos/metabolismo
6.
Cell Prolif ; 57(3): e13556, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-37828721

RESUMO

The rapid advancement of human stem cell research and its expansion into emerging areas has resulted in an escalation of ethical challenges associated with these studies. As a result, there has been a corresponding increase in both the volume and complexity of institutional ethics reviews, coupled with higher expectations for the quality of the review process. In response to these challenges, this standard provides a comprehensive outline of the fundamental principles, content, types, and procedures of ethics review, specifically focusing on non-clinical human stem cell research. Its purpose is to provide clear operational and procedural guidelines, as well as recommendations, for the ethics review of such studies. The document was originally published by the Chinese Society for Cell Biology on August 30, 2022. It is our hope that the publication of these guidelines will facilitate the integration of ethical considerations and evaluations in a structured manner throughout the entire process of stem cell research, ultimately fostering a healthy and orderly development of the field.


Assuntos
Pesquisa com Células-Tronco , Humanos
7.
Cell Prolif ; 57(5): e13588, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38124457

RESUMO

'Requirements for Human Natural Killer Cells' is the latest set of guidelines on human NK cells in China, jointly drafted and agreed upon by experts from the Standards Committee of Chinese Society for Cell Biology. This standard specifies requirements for the human natural killer (NK) cells, including the technical requirements, test methods, test regulations, instructions for use, labeling requirements, packaging requirements, storage and transportation requirements, and waste disposal requirements of NK cells. This standard is applicable for the quality control of NK cells, derived from human tissues, or differentiated/transdifferentiated from stem cells. It was originally released by the Chinese Society for Cell Biology on 30 August, 2022. We hope that the publication of these guidelines will promote institutional establishment, acceptance, and execution of proper protocols and accelerate the international standardization of human NK cells for applications.


Assuntos
Células Matadoras Naturais , Células Matadoras Naturais/imunologia , Células Matadoras Naturais/citologia , Humanos , China , Controle de Qualidade
8.
Nat Commun ; 14(1): 8163, 2023 Dec 09.
Artigo em Inglês | MEDLINE | ID: mdl-38071210

RESUMO

Cultured meat production has emerged as a breakthrough technology for the global food industry with the potential to reduce challenges associated with environmental sustainability, global public health, animal welfare, and competition for food between humans and animals. The muscle stem cell lines currently used for cultured meat cannot be passaged in vitro for extended periods of time. Here, we develop a directional differentiation system of porcine pre-gastrulation epiblast stem cells (pgEpiSCs) with stable cellular features and achieve serum-free myogenic differentiation of the pgEpiSCs. We show that the pgEpiSCs-derived skeletal muscle progenitor cells and skeletal muscle fibers have typical muscle cell characteristics and display skeletal muscle transcriptional features during myogenic differentiation. Importantly, we establish a three-dimensional differentiation system for shaping cultured tissue by screening plant-based edible scaffolds of non-animal origin, followed by the generation of pgEpiSCs-derived cultured meat. These advances provide a technical approach for the development of cultured meat.


Assuntos
Músculo Esquelético , Células-Tronco , Humanos , Animais , Suínos , Músculo Esquelético/metabolismo , Fibras Musculares Esqueléticas/metabolismo , Diferenciação Celular , Carne , Células Cultivadas
9.
Foods ; 12(17)2023 Aug 24.
Artigo em Inglês | MEDLINE | ID: mdl-37685118

RESUMO

Gamma-aminobutyric acid (GABA) is an important non-proteinogenic amino acid and a potent bioactive compound with many anti-hypertensive and anti-depressant activities. The bioconversion of GABA by glutamic acid decarboxylase (GAD) has been eagerly studied. Herein, novel pyridoxal-5-phosphate monohydrates (PLP)-dependent GAD, which is not quite similar to reporting, was cloned from Latilactobacillus curvatus and efficiently expressed in E. coli. The conveniently purified GAD (designated LcGAD10s) appeared as a single protein on SDS-PAGE with a molecular mass of 52.0 kDa. LcGAD10s exhibited a specific activity of 303.7 U/mg after purification by Ni-IDA affinity chromatography, with optimal activity at 55 °C and pH 5. LcGAD10s displayed excellent temperature (50 °C) and pH (4-8) stability which relative activity above 80% and 70%, respectively. The enzymatic activity was, respectively, increased and depressed by 130%, and 24% in the presence of Mn+ and Cu2+. Enzyme activity over 90% can be achieved by adding at least 25 mM of PLP. LcGAD10s was able to efficiently transform 15 g/L GABA with a single-factor optimized reaction of pH (5), temperature (50 °C), time (2 h), LcGAD10s dosage (0.4 U) and monosodium glutamate level (5 g/L). Additionally, LcGAD10s can be applied to a tofu fermentation system to achieve GABA conversion and achieved 14.9 mg/g of GABA conversion when added at 2 U/mL, which is higher than most of the commercial sufu and previous application reports, increasing its functional substances.

10.
Foods ; 12(18)2023 Sep 08.
Artigo em Inglês | MEDLINE | ID: mdl-37761088

RESUMO

Walnuts are one of the world's most important nut species and are popular for their high nutritional value, but the processing of walnuts produces numerous by-products. Among them, Diaphragma Juglandis Fructus has attracted the attention of researchers due to its complex chemical composition and diverse bioactivities. However, comprehensive reviews of extract activity and mechanistic studies, chemical composition functionality, and product types are scarce. Therefore, the aim of this review is to analyze the extracts, chemical composition, and product development of Diaphragma Juglandis Fructus. Conclusions: For extracts, the biological activities of aqueous and ethanol extracts have been studied more extensively than those of methanol extracts, but almost all of the studies have been based on crude extracts, with fewer explorations of their mechanisms. For chemical composition, the bioactivities of polyphenols and polysaccharides were more intensively studied, while other chemical constituents were at the stage of content determination. For product development, walnuts are mainly used in food and medicine, but the product range is limited. In the future, research on the bioactivity and related mechanisms of Diaphragma Juglandis Fructus can be further expanded to improve its value as a potential natural plant resource applied in multiple industries.

11.
Front Aging Neurosci ; 15: 1163349, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37520130

RESUMO

Objective: Arteriolosclerosis cerebral small vessel disease (CSVD) is a common type of CSVD. This study aimed to explore the factors associated with cognitive function and total MRI burden related to the disease. Methods: The demographic characteristics, clinical manifestations, cognitive function score, Barthel Index (BI), blood test index, and follow-up results of arteriolosclerosis CSVD patients treated for the first time in our hospital from January 2014 to August 2022 were collected. White matter hyperintensity (WMH) Fazekas score, total MRI burden, and cerebral atrophy grade were evaluated according to brain MRI findings. Factors associated with CSVD cognitive function were analyzed by binary logistic regression. The correlative factors related to the total MRI burden of CSVD were analyzed by ordered multiple logistic regression. Results: A total of 146 patients were included in this study, of which 132 cases (90.4%) had hypertension. There were 108 patients (74.0%) with cognitive dysfunction, 97 patients (66.4%) with balance and gait disorders, and 83 patients (56.8%) with moderate-to-severe dependence in daily life (BI ≤ 60 points). Of 146 patients, 79 (54.1%) completed clinical and imaging follow-ups for a median of 3 years. The number of patients with cognitive impairment and BI ≤ 60 points after follow-up significantly increased compared with the first admission (P < 0.001). There were also significant differences in total MRI burden (P = 0.001), WMH Fazekas score, and cerebral atrophy grade (P < 0.001). Mean age (P = 0.012), median deep WMH Fazekas score (P = 0.028), and median deep (P < 0.001) and superficial (P =0.002) cerebral atrophy grade of patients with cognitive impairment at first admission were all higher than those with non-cognitive impairment. Multivariate analysis showed that deep cerebral atrophy was independently and significantly associated with cognitive impairment of CSVD (P = 0.024), and hypertension was significantly and independently associated with total MRI burden (P = 0.001). Conclusion: The disease course of arteriolosclerosis CSVD may be related to cognitive function and total MRI burden. Deep cerebral atrophy was an independent risk factor for cognitive dysfunction in arteriolosclerosis CSVD, and hypertension was an independent risk factor for total MRI burden.

12.
Cell Regen ; 12(1): 23, 2023 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-37314549

RESUMO

Organoids have attracted great interest for disease modelling, drug discovery and development, and tissue growth and homeostasis investigations. However, lack of standards for quality control has become a prominent obstacle to limit their translation into clinic and other applications. "Human intestinal organoids" is the first guideline on human intestinal organoids in China, jointly drafted and agreed by the experts from the Chinese Society for Cell Biology and its branch society: the Chinese Society for Stem Cell Research. This standard specifies terms and definitions, technical requirements, test methods, inspection rules for human intestinal organoids, which is applicable to quality control during the process of manufacturing and testing of human intestinal organoids. It was originally released by the Chinese Society for Cell Biology on 24 September 2022. We hope that the publication of this standard will guide institutional establishment, acceptance and execution of proper practical protocols and accelerate the international standardization of human intestinal organoids for applications.

13.
Cell Regen ; 12(1): 24, 2023 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-37378693

RESUMO

Intestinal cancer is one of the most frequent and lethal types of cancer. Modeling intestinal cancer using organoids has emerged in the last decade. Human intestinal cancer organoids are physiologically relevant in vitro models, which provides an unprecedented opportunity for fundamental and applied research in colorectal cancer. "Human intestinal cancer organoids" is the first set of guidelines on human intestinal organoids in China, jointly drafted and agreed by the experts from the Chinese Society for Cell Biology and its branch society: the Chinese Society for Stem Cell Research. This standard specifies terms and definitions, technical requirements, test methods for human intestinal cancer organoids, which apply to the production and quality control during the process of manufacturing and testing of human intestinal cancer organoids. It was released by the Chinese Society for Cell Biology on 24 September 2022. We hope that the publication of this standard will guide institutional establishment, acceptance and execution of proper practocal protocols, and accelerate the international standardization of human intestinal cancer organoids for clinical development and therapeutic applications.

14.
Artigo em Inglês | MEDLINE | ID: mdl-37211578

RESUMO

Brevibacillus laterosporus has been added as a direct-fed microbiota to chicken. Yet, few studies have reported the effects of B. laterosporus on broiler growth and gut microbiota. The aim of this study was to evaluate the effects of B. laterosporus S62-9 on growth performance, immunity, cecal microbiota, and metabolites in broilers. A total of 160 1-day-old broilers were randomly divided into S62-9 and control groups, with or without 106 CFU/g B. laterosporus S62-9 supplementation, respectively. During the 42 days feeding, body weight and feed intake were recorded weekly. Serum was collected for immunoglobulin determination, and cecal contents were taken for 16S rDNA analysis and metabolome at Day 42. Results indicated that the broilers in S62-9 group showed an increase in body weight of 7.2% and 5.19% improvement in feed conversion ratio compared to the control group. The B. laterosporus S62-9 supplementation promoted the maturation of immune organs and increased the concentration of serum immunoglobulins. Furthermore, the α-diversity of cecal microbiota was improved in the S62-9 group. B. laterosporus S62-9 supplementation increased the relative abundance of beneficial bacteria including Akkermansia, Bifidobacterium, and Lactobacillus, while decreased the relative abundance of pathogens including Klebsiella and Pseudomonas. Untargeted metabolomics revealed that 53 differential metabolites between the two groups. The differential metabolites were enriched in 4 amino acid metabolic pathways, including arginine biosynthesis and glutathione metabolism. In summary, B. laterosporus S62-9 supplementation could improve the growth performance and immunity through the regulation of gut microbiota and metabolome in broilers.

15.
Foods ; 12(7)2023 Apr 06.
Artigo em Inglês | MEDLINE | ID: mdl-37048374

RESUMO

The preparation of novel antioxidant peptides from food raw materials is one of the research focuses, but there are fewer studies on the preparation of antioxidant peptides from walnut meal, a by-product of processing walnuts. This study analyzed the antioxidant properties and protective effects of walnut protein hydrolyzed by alkaline protease and trypsin on the oxidative stress of HT22 cells. The peptides were identified by UPLC-MS/MS, and the anti-oxidative peptides were screened based on virtual computer tools. The potential anti-oxidative stress mechanism of the walnut polypeptide on HT22 cells was explored by molecular docking. The results revealed that walnut protein hydrolysates (WPH) with molecular weights of less than 1 kDa had good antioxidant properties and inhibited oxidative damage of HT22 cells by regulating the levels of reactive oxygen species (ROS) and antioxidant enzyme catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px). Six of the ninety identified new peptides showed good solubility, non-toxicity, and bioactivity. The molecular docking results showed that the six peptides could dock with Keap1 successfully, and EYWNR and FQLPR (single-letter forms of peptide writing) could interact with the binding site of Nrf2 in the Keap1-Kelch structural domain through hydrogen bonds with strong binding forces. The results of this study provided important information on the antioxidant molecular mechanism of the walnut polypeptide and provided a basis for further development of walnut antioxidant polypeptide products.

16.
Foods ; 12(2)2023 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-36673380

RESUMO

Probiotics are being used in diets to improve the quality of chicken meat. The aim of the study was to investigate the effects of dietary supplementation with Brevibacillus laterosporus S62-9 microbial agent on the meat quality, amino acids, and volatile compounds of chicken. The experiment was carried out with 160 1-day-old Arbor Acres male broiler chickens, rearing for 42 d. The chickens were randomly divided into two groups of 8 replicates each, with 10 chickens in each group. No supplement was added to the basal diet in the control group and Brevibacillus laterosporus S62-9 microbial agent was added to the diet of the experimental group. At the end of the experiment, the meat quality, meat chemical composition, amino acid composition, and volatile compounds of chicken were determined. The results showed that pH (p < 0.05), pressing loss (p < 0.05), cooking loss (p < 0.05), and shear force (p < 0.01) were notably decreased, the percentage of breast meat (p < 0.01), protein content (p < 0.05) were visibly increased, and remarkable changes were observed in the amino acid composition (change in seven amino acids) and volatile compounds profile (an increase of about 20-fold in the contents of 1-octen-3-ol and hexanal). In summary, it was found that Brevibacillus laterosporus S62-9 microbial agent can be used as a novel and effective feed supplement to improve the nutritional quality and flavor characteristics of broilers.

17.
Front Neurol ; 13: 1057935, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36530619

RESUMO

Background: Endovascular treatment (EVT) is one of the effective treatment procedure for the symptomatic intracranial atherosclerotic stenosis (sICAS). Aim and methods: We evaluated the efficacy and safety of individualized endovascular treatment for sICAS patients. Clinical and imaging follow-ups were carried out to collect the data of 29 sICAS patients after 6 months of individualized endovascular treatment. Different treatment strategies are selected based on arterial access and lesion morphology of patients. If standard surgical path, narrow artery straight, stenosis length ≤10 mm, then the appropriate specifications of balloon-mounted stent (BMS) treatment. the surgical path is tortuous, the narrow artery is curved, the angle is apparent, the diameter of the near and far ends is significantly different, or the length of the stenosis is >10 mm, self-expanding stent (SES) with appropriate specifications is selected for treatment. If the narrowed artery is hyper flexed and the surgeon deems stenting inappropriate, balloon dilation angioplasty (BDA) treatment is chosen. Results and conclusion: 31 lesions of 29 sICAS patients received endovascular treatment. The median age was 61 years (IQR 54-69 years). The median preoperative stenosis was 90% (IQR 80-95%), and the mean stenosis length was (8.10 ± 3.27) mm. The most commonly used surgical procedure was Balloon-Mounted Stent (BMS) in 19 cases (65.52%), Self-expanding Stent (SES) in seven cases (24.14%), Balloon Dilation Angioplasty (BDA) in three cases (10.34%). (11.86 + 1.46 mm) was greater than that in the BMS group (6.14 + 1.59 mm) (P < 0.001). The median stenosis was 90% (IQR 80-92.5%) in the BMS group, lower than 99% (IQR 95-100%) in the SES group (P < 0.001). The median post-operative residual stenosis was 20% (IQR 15-25%), significantly improved compared with preoperative (P < 0.001). The success rate of the surgical technique was 93.10% (27/29). One patient (3.45%) had IS recurrence within 48 h after surgery, and the restenosis rate within 6 months after surgery was 6.90% (2/29). No patient died or had recurrent IS. Our data demonstrated that individualized endovascular treatment method could be potentially significant and safe for sICAS patients. This study will provide an important reference for the endovascular treatment of sICAD.

18.
Foods ; 11(19)2022 Sep 26.
Artigo em Inglês | MEDLINE | ID: mdl-36230066

RESUMO

Bacterial contamination is a primary threat to food safety. Therefore, the persistent development of natural antibacterial agents has become essential work. The present essay attempts to establish a systematic antibacterial activity database to instruct the food application of brevilaterins, promising antibacterial lipopeptides from Brevibacillus laterosporus S62-9. Minimum inhibitory concentrations (MIC) and minimum bactericidal concentrations (MBC) were systematically collected from 43 species of standard bacteria and 140 strains of isolated bacteria (food spoilage bacteria and antibiotic-resistant bacteria) using a broth dilution method. The results showed that brevilaterins performed a broad-spectrum inhibitory (0.5~128 µg/mL) and bactericidal activity (1~256 µg/mL), especially efficient against Gram-positive bacteria and spoilage bacteria from grain products. Moreover, brevilaterins not only inhibit and kill multiple antibiotic-resistant bacteria but do not readily develop resistance, with a small specific value of MBC/MIC (1~8). Furthermore, brevilaterins would interact with negatively charged sodium dodecyl sulfate and bind amphipathic soybean phospholipid with an affinity constant of KD = 4.70 × 10-4 M. No significant activity difference was found between brevilaterin B and brevilaterin C. Collectively, this work contributed rich antibacterial data of brevilaterins and revealed the antibacterial regularity beneath these data, which can be used as an activity handbook to instruct their application in food safety.

19.
Microb Cell Fact ; 21(1): 196, 2022 Sep 19.
Artigo em Inglês | MEDLINE | ID: mdl-36123650

RESUMO

BACKGROUND: Brevilaterin A-E, a novel class of multi-component cationic antimicrobial lipopeptides, were biosynthesized by a non-ribosomal peptides synthetase (NRPS) in Brevibacillus laterosporus. However, the antimicrobial abilities of different brevilaterin components varied greatly, and this multi-component form was impeding the scale production of the excellent component, and a little information about the brevilaterin biosynthesis mechanism was available to apply in brevilaterin design modification. In this study, we used an accurate strategy that revealed the reason for producing multi-component was the substrate selectivity of bre2691A protein being not enough specific and pinpointed the key design sites to make the specificity of bre2691A enhanced. RESULTS: Bioinformatic analysis revealed that the biocatalytic site of bre2691A, which was an adenylation domain catalyzed and recognized methionine, leucine, valine and isoleucine and thus introduced them into brevilaterins and caused different components (brevilaterin A-E), was consisted of A1 ~ A10 residues named specificity-conferring code. Coupling molecular docking simulations with mutation studies identified A2 and A7 as critical residues, where determined substrate-specificity and impacted activity. The in virto activity assay showed that the A2 mutant (G193A) would lose activity against methionine and have no effect on the other three amino acids, the A7 mutant (G285C) would enhance the catalytic activity against four substrates, especially against leucine at almost a double activity. When the A2 and A7 residues were synchronously mutated, this mutant would be more focused on recognizing leucine. CONCLUSIONS: An accurate strategy that combined with bioinformatics and site-directed mutation techniques revealed the pivotal site A2 and A7 positions of bre2691A protein that could be used to design and modify brevilaterins, thus further providing a reasonable direction of genetic engineering for Brevibacillus laterosporus. A deeper understanding of the function of crucial residues in the adenylation domain would make it get more accurate and highly efficient design and more fully utilized. Furthermore, it would contribute to biotechnological applications, namely for the large centralized synthesis of antimicrobial peptides, or for the optimization of their production.


Assuntos
Anti-Infecciosos , Bacillus , Proteínas de Bactérias/metabolismo , Aminoácidos , Antibacterianos/química , Biocatálise , Brevibacillus , Isoleucina , Leucina , Lipopeptídeos/genética , Metionina , Simulação de Acoplamento Molecular , Valina
20.
Food Res Int ; 159: 111641, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-35940770

RESUMO

Listeria monocytogenes is a food-borne pathogen that can cause human listeriosis. The main cause of L.monocytogenes poisoning is the consumption of contaminated or processed foods, of which meat is the main one. At present, it is not clear whether the listeria contaminated in different meatis genetically diverse. In this study, a total of 90 L.monocytogenes isolates including 28 isolates in livestock meat and 62 isolates in poultry meat were obtained from chicken, duck, pork, and beef respectively in Beijing. And whole-genome sequencing (WGS) based analysis was performed to investigate the genetic diversity of L.monocytogenes between poultry and livestock meat isolates. As a result, we found the prevalence of the multilocus sequence typing (MLST)-derived clonal complexes (CCs) were quite different between two different types of meat. The number of resistance genes and virulence genes in most of the L.monocytogenes isolated from the four meat species were close, but the sequences of eight resistance genes and 19 virulence genes were significantly varied between poultry meat and livestock meat. The phylogenetic and collinear analysis of these isolates revealed the isolates in the same meat have a similar genome. These results showed that the genetic variation of L.monocytogenes in livestock and poultry meat were significantly different isolates.


Assuntos
Listeria monocytogenes , Animais , Bovinos , Microbiologia de Alimentos , Humanos , Gado/genética , Carne , Tipagem de Sequências Multilocus , Filogenia , Aves Domésticas
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