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Methicillin-resistant S. aureus (MRSA) has been considered a potential "Super Bugs", responsible for various infectious diseases. Vancomycin has been the most effective antibitic to treat MRSA originated infections. In this study, we aimed at investigating the genomic features of a vancomycin intermediate-resistance S. aureus strain Guangzhou-SauVS2 isolated from a female patient suffering from chronic renal function failure, emphasizing on its antimicrobial resistance and virulence determinants. The genome has a total length of 2,605,384 bp and the G+C content of 33.21%, with 2,239 predicted genes annotated with GO terms, COG categories, and KEGG pathways. Besides the carriage of vancomycin b-type resistance protein responsible for the vancomycin intermediate-resistance, S. aureus strain Guangzhou-SauVS2 showed resistance to ß-lactams, quinolones, macrolide, and tetracycline, due to the acquisition of corresponding antimicrobial resistance genes. In addition, virulence factors including adherence, antiphagocytosis, iron uptake, and toxin were determined, indicating the pathogenesis of the strain.
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Staphylococcus aureus Resistente a Meticilina , Infecciones Estafilocócicas , Antibacterianos/farmacología , Femenino , Humanos , Staphylococcus aureus Resistente a Meticilina/genética , Pruebas de Sensibilidad Microbiana , Staphylococcus aureus/genética , Vancomicina/farmacologíaRESUMEN
Herein, an ultrasensitive electrochemiluminescent (ECL) strategy was proposed based on a highly efficient dynamic DNA machine based on microRNA triggered free movement on the lipid bilayer interface. Typically, the lipid bilayer is constructed on the electrode surface modified with nafion@ECL luminophore and gold nanoparticles to immobilize the DNA walker labeled with cholesterol and hairpin nucleotides labeled with cholesterol and ferrocene (Fc), based on the cholesterol-lipid interaction. On this state, Fc was close to the ECL luminophore, performing a quenched ECL emission. In the presence of target microRNA 21, it could trigger the entropy beacon-based DNA amplification to convert microRNA to massive special DNA sequences, which could further hybridize with the blocking DNA on DNA walker to reactivate the DNA walker and thus trigger the DNA walker-based amplification to make Fc to be far from the ECL luminophore, performing a recovered ECL emission related with the concentration of microRNA 21. Compared with the conventional DNA walker immobilized on the interface via chemical bonds or physical adsorption, a higher reaction efficiency could be achieved due to the free movements of DNA walker and its substrates on the interface. As expected, satisfactory performances for the detection of microRNA 21 were achieved with a detection limit of 0.4 fM and quantitative estimation in cells. Furthermore, this dynamic DNA machine-based ECL strategy could be readily expanded for the detection of other biomarkers for clinical diagnosis.
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Técnicas Biosensibles , ADN/química , Técnicas Electroquímicas , Membrana Dobles de Lípidos/química , Mediciones Luminiscentes , MicroARNs/química , Termodinámica , Electrodos , Células HeLa , Humanos , Células MCF-7 , Técnicas de Amplificación de Ácido Nucleico , Propiedades de Superficie , Células Tumorales CultivadasRESUMEN
The direct role of melatonin in mammary glands of dairy goats has remained obscure. This study aimed to evaluate the expression of melatonin membrane receptors (MT1 and MT2) in the pituitary and mammary glands of dairy goats during lactation, and to investigate the role of melatonin in mammary function. Both MT1 and MT2 were consistently expressed in the pituitary and mammary eight glands throughout the lactation period, and their levels were lower in 9 March (group I), June (group III), and September (group V) than in May (group II) and August (group IV). The expression patterns of pituitary and mammary MT1 and MT2 were consistent with those of blood melatonin during lactation. Furthermore, the mammary prolactin (PRL), and pituitary growth hormone (GH) and PRL mRNA expression showed an inverse trend in relation to blood melatonin levels. In mammary tissues, MT1 and MT2 immunoreactivity was predominantly located in the mammary epithelial cells (MECs). In addition, a dose- and time-dependent inhibition on cell viability was observed in cultured MECs. At the dose of 10 and 100 pg/ml, melatonin decreased mammary ß-casein and PRL expression. Furthermore, the inhibitory effects of melatonin were blocked by luzindole, a nonselective MT1 and MT2 receptor antagonist. In addition, melatonin promoted MT1 and MT2 expression in cultured MECs. In conclusion, the presence of MT1 and MT2 in the pituitary and mammary glands and the inhibitory effects of melatonin on cell viability, ß-casein, and PRL expression in MECs suggest the potential regulation by melatonin in goat mammary function.
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Cabras/fisiología , Lactancia/efectos de los fármacos , Glándulas Mamarias Animales/efectos de los fármacos , Melatonina/farmacología , Animales , Caseínas/genética , Caseínas/metabolismo , Proliferación Celular/efectos de los fármacos , Supervivencia Celular , Femenino , Regulación de la Expresión Génica , Metaloproteinasa 14 de la Matriz/genética , Metaloproteinasa 14 de la Matriz/metabolismo , Metaloproteinasa 15 de la Matriz/genética , Metaloproteinasa 15 de la Matriz/metabolismo , Prolactina/genética , Prolactina/metabolismoRESUMEN
Little is known about ghrelin's effects on cell proliferation in pregnant mammary epithelial cells (MECs) even though it is known to be a mitogen for a variety of other cell types. The objectives of this study were to evaluate the expression and localization of ghrelin and its functional receptor, GHSR-1a, in the mammary glands of dairy goats during pregnancy and to investigate the direct role of ghrelin in cell proliferation of primary cultured MECs. Compared to the early stage (days 30) of pregnancy, the abundance of transcripts and protein of ghrelin and GHSR-1a were significantly greater in mid- and late-phases (between days 90 and days 120) of pregnancy (pâ¯<â¯.05). Immunohistochemistry analysis showed that ghrelin and GHSR-1a were predominantly localized in the alveolar and ductal mammary epithelial cells at various stages of pregnancy. In our in vitro experiments, ghrelin induced a dose- and time-dependent promotory effect on cell proliferation of MECs. At the dose of 103â¯pg/mL treatment 24â¯h, ghrelin augmented the expression of proliferation-related peptides (PCNA and cyclin B1). Furthermore, ghrelin promoted the expression of prolactin (PRL) and GHSR-1a in cultured MECs. Additionally, the stimulatory effects of ghrelin were blocked by d-Lys3-GHRP6, a selective antagonist of GHSR-1a. As the temporal changes in ghrelin and GHSR-1a expression in pregnant goat mammary glands coincided with the mammary growth and development during the pregnancy, activation of GHSR-1a signal transduction pathways by ghrelin may play a direct role in the regulation of mammary growth in dairy goats.
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Proliferación Celular , Células Epiteliales/fisiología , Ghrelina/genética , Ghrelina/farmacología , Cabras , Glándulas Mamarias Animales/metabolismo , Preñez , Animales , Proliferación Celular/efectos de los fármacos , Proliferación Celular/genética , Células Cultivadas , Industria Lechera , Células Epiteliales/efectos de los fármacos , Células Epiteliales/metabolismo , Femenino , Ghrelina/metabolismo , Cabras/genética , Cabras/fisiología , Lactancia/genética , Glándulas Mamarias Animales/citología , Glándulas Mamarias Animales/crecimiento & desarrollo , Embarazo , Receptores de Ghrelina/genética , Receptores de Ghrelina/metabolismo , Transducción de Señal/efectos de los fármacosRESUMEN
Combined hyperlipidemia (CHL) manifests as elevated cholesterol and triglycerides, associated with fatty liver and cardiovascular diseases. Emerging evidence underscores the crucial role of the intestinal microbiota in metabolic disorders. However, the potential therapeutic viability of remodeling the intestinal microbiota in CHL remains uncertain. In this study, CHL was induced in low-density lipoprotein receptor-deficient (LDLR-/-) hamsters through an 8-week high-fat and high-cholesterol (HFHC) diet or a 4-month high-cholesterol (HC) diet. Placebo or antibiotics were administered through separate or cohousing approaches. Analysis through 16S rDNA sequencing revealed that intermittent antibiotic treatment and the cohousing approach effectively modulated the gut microbiota community without impacting its overall abundance in LDLR-/- hamsters exhibiting severe CHL. Antibiotic treatment mitigated HFHC diet-induced obesity, hyperglycemia, and hyperlipidemia, enhancing thermogenesis and alleviating nonalcoholic steatohepatitis (NASH), concurrently reducing atherosclerotic lesions in LDLR-/- hamsters. Metabolomic analysis revealed a favorable liver lipid metabolism profile. Increased levels of microbiota-derived metabolites, notably butyrate and glycylglycine, also ameliorated NASH and atherosclerosis in HFHC diet-fed LDLR-/- hamsters. Notably, antibiotics, butyrate, and glycylglycine treatment exhibited protective effects in LDLR-/- hamsters on an HC diet, aligning with outcomes observed in the HFHC diet scenario. Our findings highlight the efficacy of remodeling gut microbiota through antibiotic treatment and cohousing in improving obesity, NASH, and atherosclerosis associated with refractory CHL. Increased levels of beneficial microbiota-derived metabolites suggest a potential avenue for microbiome-mediated therapies in addressing CHL-associated diseases.
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Lithium-sulfur batteries (LSBs) have become highly promising next-generation secondary lithium batteries owing to their high theoretical energy density and abundance of sulfur. Nevertheless, the large-scale application of LSBs is still restricted by the shuttle effect of lithium polysulfide (LiPSs) and the potential fire hazard caused by flammable electrolytes. Herein, three electrolyte-insoluble brominated flame retardants (BFRs) are selected and coated on both sides of commercial polypropylene separators by a facile slurry coating method. The effects of the three BFRs on the safety and electrochemical properties of LSBs are characterized and compared. The coating modification separators greatly improves the flame retardancy of LSBs through radical elimination mechanism. The self-extinguishing time of the electrolyte is reduced from 0.66 s/mg to 0.20 s/mg. Moreover, it is demonstrated that the oxygen (O)-containing BFRs exert a significant adsorption capacity and are more advantageous than O-free BFRs in LSBs. In addition, octabromoether (BDDP) coated separator is more effective in trapping LiPSs than decabromodiphenyl ether (DBDPO) due to higher O content, which can mitigate the shuttle effect and enhance the cycle and rate performance of LSBs. This simple coating strategy for separators with BFRs offers a strongly competitive option for the large-scale production of high-safety LSBs.
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Objective: Learner dependence on short videos has many pitfalls for learning outcomes, but the negative effects of excessive short video use have been little discussed in the learning psychology literature. Therefore, this study investigated the effects of excessive short video use on anxiety, depression, prospective memory, and academically delayed gratification (ADOG) in relation to online gaming-related behaviours, and explored the possible mechanisms by which excessive online gaming and short video use may lead to decreased ADOG, to expand our understanding of excessive short video use. Methods: Based on the whole class random sampling method, a questionnaire survey was conducted among college students in Northern Anhui, China from May 7 to July 27, 2022. The questionnaires included the Generalized Anxiety Disorder Scale (GAD-7), Patient Health Questionnaire Scale (PHQ-9), Prospective and Retrospective Memory (PRM) Questionnaire, and ADOG Scale. Results: A total of 1016 participants completed the survey. The study found that of all the internet behaviors, 20.8% of the college students mainly played online games, 43.9% mainly played short videos, and 35.3% conducted other online behaviors. When compared with other internet behaviors, online gaming and short video behaviors can cause more serious anxiety/depression and worse PRM and ADOG scores. As time spent playing online games and short videos increased, anxiety and depression became worse, and the scores for PRM and ADOG also declined. Anxiety, depression, and PRM mediate the relationship between time spent on online gaming/short videos and ADOG. Conclusion: Excessive short videos behaviour may produce the same psychological problems and learning problems as online gaming disorder. Excessive short video and online gaming behaviors may affect ADOG performance through anxiety, depression, and prospective memory. These findings could be used as a basis for future studies on the improvement of ADOG.
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Objective: Evidence from previous studies indicates that impulsive behaviors are closely linked to alcohol use and misuse and that female drinkers are more impulsive than male drinkers. However, studies investigating the psychological mechanisms of alcohol use and impulsivity based on sex differences are relatively limited. Methods: This cross-sectional study comprised 713 residents from 16 cities in Anhui Province, China. Each subject was evaluated for self-reporting measures using several questionnaires, including the general information questionnaire, the Alcohol Use Disorders Identification Test (AUDIT), the Prospective and Retrospective Memory Questionnaire (PRM), the Behavior Rating Inventory of Executive Function-Adult Version (BRIEF-A), and the Barratt Impulsiveness Scale-11 (BIS-11). Results: Executive function and prospective memory may serve as intermediary links between alcohol use and impulsivity. Although the female alcohol usage level was significantly lower than that of males, the female drinkers had more severe executive dysfunction, prospective memory impairment, and impulsivity than male drinkers. Sex moderated the relationship between alcohol use and impulsivity. Furthermore, the indirect effect of executive function, and prospective memory between AUDIT and BIS was more significant in males than in females. Conclusion: Alcohol consumption may be associated with impulsivity formation through executive dysfunction and PM impairment, implying that impulsivity in those with AUD or at risk for AUD might be treated by improving EF and PM. Alcohol use may cause more severe executive dysfunction, PM impairment, and impulsive behavior in females than in males, and impulsive behavior in women with AUD was more likely to be due to the direct effects of alcohol consumption, while impulsive behavior in men with AUD was more likely to be due to the indirect effects of executive dysfunction and PM impairment. These findings provide both clinical and theoretical foundations for addressing issues related to alcohol use.
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Alcoholismo , Memoria Episódica , Adulto , Humanos , Femenino , Masculino , Función Ejecutiva/fisiología , Alcoholismo/epidemiología , Alcoholismo/psicología , Estudios Retrospectivos , Estudios Transversales , Consumo de Bebidas Alcohólicas/epidemiología , Conducta Impulsiva/fisiologíaRESUMEN
In the past, electromagnetic interference (EMI) shielding materials have achieved great breakthroughs, however, they still suffer from high reflectivity and poor environmental stability, resulting in detrimental secondary pollution and weak adaptability. Herein, an organohydrogel-based EMI shielding material was prepared through cellulose nanofibril-based Pickering emulsion, composed of an MXene network for electron conduction, encapsulated paraffin wax microspheres with MXene-Fe3O4 shells for multiple scattering of the incident wave, and MXene-CNF-Fe3O4-polyacrylamide hybrid interfaces for dielectric polarization. The EMI shielding performance of our organohydrogel shows an absorption-dominated feature. It can effectively shield 99.625 % electromagnetic wave, satisfying the requirement of commercial EMI shielding materials. Moreover, the organohydrogel possesses excellent flame retardancy properties and long-time environment properties to improve safety and reliability; and it also demonstrates sensitive deformation responses as an on-skin sensor. Therefore, our organohydrogel can simultaneously detect human motion and protect human from EMI radiation and accidental burn.
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Celulosa , Retardadores de Llama , Fenómenos Electromagnéticos , Emulsiones , Humanos , Parafina , Reproducibilidad de los ResultadosRESUMEN
The H9N2 avian influenza virus (AIV) remains a serious threat to the global poultry industry and public health. The hemagglutinin (HA) protein is an essential protective antigen of AIVs and a major target of neutralizing antibodies and vaccines. Therefore, in this study, we used rice-derived HA protein as an immunogen to generate monoclonal antibodies (mAbs) and screened them using an immunoperoxidase monolayer assay and indirect enzyme-linked immunosorbent assay. Eight mAbs reacted well with the recombinant H9N2 AIV and HA protein, four of which exhibited potent inhibitory activity against hemagglutination, while three showed remarkable neutralization capacities. Western blotting confirmed that two mAbs bound to the HA protein. Linear epitopes were identified using the mAbs; a novel linear epitope, 480HKCDDQCM487, was identified. Structural analysis revealed that the novel linear epitope is located at the C-terminus of HA2 near the disulfide bond-linked HA1 and HA2. Alignment of the amino acid sequences showed that the epitope was highly conserved among multiple H9N2 AIV strains. The results of this study provide novel insights for refining vaccine and diagnostic strategies and expand our understanding of the immune response against AIV.
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Subtipo H9N2 del Virus de la Influenza A , Gripe Aviar , Animales , Hemaglutininas , Epítopos , Anticuerpos Neutralizantes , Anticuerpos MonoclonalesRESUMEN
The aim of this study was to develop a semi-quantitative immunochromatographic method for rapid detection of Newcastle disease virus (NDV) antibodies by expressing HN protein in rice endosperm bioreactor. The recombinant plasmid pUC57-HN was digested by Mlyâ and Xhoâ to retrieve the HN gene, while the intermediate vector pMP3 containing promoter, signal peptide and terminator was digested by Naeâ and Xhoâ . The HN gene and the linearized pMP3 were purified and ligated to form a recombinant plasmid pMP3-HN1. Subsequently, pMP3-HN1 and plant vector pCAMBIA1300 were digested by EcoRâ and Hind â ¢, and the HN1 gene was cloned into pCAMBIA1300. The recombinant plasmid pCAMBIA1300-HN1 was introduced into Agrobacterium tumefaciens EHA105 by electrotransformation, and the pCAMBIA1300-HN1 was transferred into rice callus by agrobacterium-mediated method. After dark culture, callus screening, differentiation, rooting and transplanting, transgenic rice seeds were obtained 4 months later. PCR identified that the HN gene has been inserted into the rice genome. SDS-PAGE and Western blotting indicated that the HN protein was successfully expressed in the positive rice endosperm. The purity of the HN protein was more than 90% by SP cation exchange chromatography and gel filtration chromatography. According to the national standards for the diagnostic techniques of Newcastle disease HI test (HI≥4log2, positive antibody reaction), a colloidal gold labeled purified HN protein was used to prepare a semi-quantitative test strip by double-antibody sandwich method for rapid detection of NDV antibody. The results showed that the test strip did not cross-react with positive sera against other viruses, and the sensitivity of the test strip reached 1:102 400 for standard positive sera of Newcastle disease. Testing of a total of 308 clinical sera showed that the compliance rate of the test strip with HI test was 97.08%, and the Kappa value was 0.942. In conclusion, high purity recombinant HN protein was obtained from rice endosperm, and a simple, rapid, highly sensitive and highly specific semi-quantitative immunochromatographic strip was developed. The test strip could be used for immune evaluation of the Newcastle disease vaccine.
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Enfermedad de Newcastle , Oryza , Animales , Anticuerpos Antivirales , Pollos , Proteína HN/genética , Proteína HN/metabolismo , Enfermedad de Newcastle/prevención & control , Virus de la Enfermedad de Newcastle/genética , Virus de la Enfermedad de Newcastle/metabolismo , Oryza/genéticaRESUMEN
To achieve the co-delivery of chemotherapeutic drugs, genes, and immune agents in a single nanoparticulate system, p-mercaptobenzoic acid-grafted N, N, N-trimethyl chitosan nanoparticles (MT NPs) were successfully synthesized. Paclitaxel (PTX) was encapsulated into the hydrophobic core of the MT NPs, and meanwhile, survivin shRNA-expressing plasmid (iSur-pDNA) and recombinant human interleukin-2 (rhIL-2) were loaded onto the hydrophilic shell of the MT NPs. Owing to the redox-sensitiveness of MT NPs, a rapid release of PTX was triggered by the high concentration of glutathione. The synergistic effects of PTX (1.5 mg/kg), iSur-pDNA (1.875 mg/kg), and rhIL-2 (6 × 105 IU/kg) at a low dose endowed the MT/PTX/pDNA/rhIL-2 NPs with enhanced antitumor efficacies and improved tumor-induced immunosuppression. These results demonstrated that the co-delivery of PTX, iSur-pDNA, and rhIL-2 by the amphiphilic chitosan based NPs with redox-sensitiveness could be a promising strategy in the treatment of tumors.
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Antineoplásicos/farmacología , Quitosano/química , Sistemas de Liberación de Medicamentos/métodos , Nanopartículas/química , Neoplasias/tratamiento farmacológico , Paclitaxel/farmacología , Animales , Antineoplásicos/química , Protocolos de Quimioterapia Combinada Antineoplásica/química , Protocolos de Quimioterapia Combinada Antineoplásica/farmacología , Línea Celular Tumoral , Femenino , Glutatión/metabolismo , Humanos , Interleucina-2/metabolismo , Ratones , Neoplasias/metabolismo , Paclitaxel/química , ARN Interferente Pequeño/metabolismo , Survivin/metabolismoRESUMEN
Objective: This study aimed to investigate the effect of environmental conditions including nutrient content, acetic acid concentration, salt concentration, and temperature on the formation of viable but nonculturable (VBNC) state of Pediococcus acidilactici, as well as its control and detection in food system. Methods: Representing various environmental conditions in different food systems, 16 induction groups were designed for the formation of VBNC state of P. acidilactici. Traditional plate counting was applied to measure the culturable cell numbers, and Live/Dead Bacterial Viability Kit combined with fluorescent microscopy was used to identify viable cells numbers. The inhibition of bacterial growth and VBNC state formation by adjusting the environmental conditions were investigated, and the clearance effect of VBNC cells in crystal cake system was studied. In addition, a propidium monoazide-polymerase chain reaction (PMA-PCR) assay was applied to detect the VBNC P. acidilactici cells in crystal cake food system. Results: Among the environmental conditions included in this study, acetic acid concentration had the greatest effect on the formation of VBNC state of P. acidilactici, followed by nutritional conditions and salt concentration. Reducing nutrients in the environment and treating with 1.0% acetic acid can inhibit P. acidilactici from entering the VBNC state. In the crystal cake system, the growth of P. acidilactici and the formation of VBNC state can be inhibited by adding 1.0% acetic acid and storing at -20°C. In crystal cake system, the PMA-PCR assay can be used to detect VBNC P. acidilactici cells at a concentration higher than 104 cells/ml. Conclusion: The VBNC state of P. acidilactici can be influenced by the changing of environmental conditions, and PMA-PCR assay can be applied in food system for the detection of VBNC P. acidilactici cells.
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A Viable but non-culturable (VBNC) state is a bacterial survival strategy under reverse conditions. It poses a significant challenge for public health and food safety. In this study, the effect of external environmental conditions including acid, nutrition, and salt concentrations on the formation of S. aureus VBNC states at low temperatures were investigated. Different acidity and nutritional conditions were then applied to food products to control the VBNC state formation. Four different concentration levels of each factor (acid, nutrition, and salt) were selected in a total of 16 experimental groups. Nutrition showed the highest influence on the VBNC state formation S. aureus, followed by acid and salt. The addition of 1% acetic acid could directly kill S. aureus cells and inhibit the formation of the VBNC state with a nutrition concentration of 25, 50, and 100%. A propidium monoazide-polymerase chain reaction (PMA-PCR) assay was applied and considered as a rapid and sensitive method to detect S. aureus in VBNC state with the detection limit of 104 CFU/mL.
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Lactic acid bacteria (LAB) have caused many microbiological incidents in the brewing industry, resulting in severe economic loss. Meanwhile, traditional culturing method for detecting LAB are time-consuming for brewers. The present review introduces LAB as spoilage microbes in daily life, with focus on LAB in the brewing industry, targeting at the spoilage mechanism of LAB in brewing industry including the special metabolisms, the exist of the viable but nonculturable (VBNC) state and the hop resistance. At the same time, this review compares the traditional and novel rapid detection methods for these microorganisms which may provide innovative control and detection strategies for preventing alcoholic beverage spoilage, such as improvement of microbiological quality control using advanced culture media or different isothermal amplification methods.
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Industria de Alimentos , Microbiología de Alimentos , Lactobacillales , Cerveza , Medios de Cultivo , Contaminación de Alimentos , Inocuidad de los AlimentosRESUMEN
The inhibition of microbial biofilms is a significant concern in food safety. In the present study, the inhibitory effect of sodium citrate and cinnamic aldehyde on biofilm formation at minimum inhibitory concentrations (MICs) and sub-MICs was investigated for Escherichia coli O157:H7 and Staphylococcus aureus. The biofilm inhibition rate was measured to evaluate the effect of sodium citrate on S. aureus biofilms at 24, 48, 72, and 96 hr. According to the results, an antibiofilm effect was shown by both food additives, with 10 mg/ml of sodium citrate exhibiting the greatest inhibition of S. aureus biofilms at 24 hr (inhibition rate as high as 77.51%). These findings strongly suggest that sodium citrate exhibits a pronounced inhibitory effect on biofilm formation with great potential in the extension of food preservation and storage.
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Antibacterianos/farmacología , Biopelículas/efectos de los fármacos , Escherichia coli O157/efectos de los fármacos , Aditivos Alimentarios/farmacología , Staphylococcus aureus/efectos de los fármacos , Acroleína/análogos & derivados , Acroleína/farmacología , Pruebas de Sensibilidad Microbiana , Citrato de Sodio/farmacología , Factores de TiempoRESUMEN
The direct effect of melatonin on porcine luteal function during the pregnancy remains unknown. The objective of the study was to analyse the molecular mechanism(s) by which melatonin directly affects progesterone (P4) production in the corpus luteum (CL) of pregnant sows. We evaluated the localization of melatonin membrane receptors (MT1 and MT2) in CL, and investigated the effect of melatonin on P4 secretion along with the expression of P4 synthesis intermediates in luteal cells. Immunohistochemistry analysis showed that MT1 and MT2 were predominantly localized in luteal cells in pregnant luteal tissues. The results of our in vitro experiments showed that melatonin from 5 to 625â¯pg/mL was able to significantly increase P4 release (Pâ¯<â¯0.05) in a dose-dependent manner. And at the dose of 125â¯pg/mL treatment, the time-dependent effect on P4 secretion was observed. Furthermore, melatonin from 5 to 625â¯pg/mL up-regulated both P450scc and StAR expression (Pâ¯<â¯0.05) in a dose-dependent manner, and the effect was also time-dependent. No difference of 3ß hydroxysteroid dehydrogenase (3ß-HSD) expression was observed between control and treatment groups. In addition, melatonin induced a dose- and time-dependent promotion on cell viability. Additionally, the stimulatory effects of melatonin were blocked by luzindole, a non-selective MT1 and MT2 receptor antagonist, or partially blocked by a selective MT2 ligand, 4-phenyl-2-propionamidotetralin (4P-PDOT). The data support the presence of MT1 and MT2 in porcine CL and a regulatory role for melatonin in luteal function through MT1 and MT2-mediated signal transduction pathways.