Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 66
Filtrar
Más filtros

Banco de datos
País/Región como asunto
Tipo del documento
Intervalo de año de publicación
1.
Anim Biotechnol ; 35(1): 2346808, 2024 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-38739483

RESUMEN

This study aimed to evaluate the effect of miR-23b-3p on growth hormone (GH) in pituitary cells of Yanbian yellow cattle. The mRNA and protein levels of GH and miR-23b-3p target genes were measured by real time fluorescence quantitative PCR (qPCR) and Western blot, respectively. The target relationship of miR-23b-3p was validated by double luciferase reporter gene system. The results showed that GH mRNA and protein levels in pituitary cells of Yanbian yellow cattle were significantly lower in the miR-23b-3p-mi group than in the NC group (P<0.01), while GH mRNA and protein levels were higher in the miR-23b-3p-in group than in the iNC group (P<0.05). The result of bioinformatics analysis and double luciferase reporter gene system validation proved that miR-23b-3p targeted 3'UTR of pituitary specific transcription factor 1 (POU1F1). POU1F1 mRNA and protein levels were lower miR-23b-3p-mi group than in the NC group (P<0.01), while POU1F1 mRNA and protein levels were higher in the miR-23b-3p-in group than in the iNC group (P<0.01). These results demonstrated that miR-23b-3p could regulate GH expression in pituitary cells by regulating POU1F1 gene.


Asunto(s)
Hormona del Crecimiento , MicroARNs , Factor de Transcripción Pit-1 , Animales , Bovinos/genética , MicroARNs/genética , MicroARNs/metabolismo , Hormona del Crecimiento/genética , Hormona del Crecimiento/metabolismo , Factor de Transcripción Pit-1/genética , Factor de Transcripción Pit-1/metabolismo , Hipófisis/metabolismo , Regulación de la Expresión Génica , Regiones no Traducidas 3'/genética , ARN Mensajero/genética , ARN Mensajero/metabolismo
2.
Ecotoxicol Environ Saf ; 272: 116084, 2024 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-38350217

RESUMEN

Polyhexamethylene guanidine (PHMG) is manufactured and applied extensively due to its superior disinfectant capabilities. However, the inhalatory exposure to PHMG aerosols is increasingly recognized as a potential instigator of pulmonary fibrosis, prompting an urgent call for elucidation of the underlying pathophysiological mechanisms. Within this context, alveolar macrophages play a pivotal role in the primary immune defense in the respiratory tract. Dysregulated lipid metabolism within alveolar macrophages leads to the accumulation of foam cells, a process that is intimately linked with the pathogenesis of pulmonary fibrosis. Therefore, this study examines PHMG's effects on alveolar macrophage foaminess and its underlying mechanisms. We conducted a 3-week inhalation exposure followed by a 3-week recovery period in C57BL/6 J mice using a whole-body exposure system equipped with a disinfection aerosol generator (WESDAG). The presence of lipid-laden alveolar macrophages and downregulation of pulmonary tissue lipid transport proteins ABCA1 and ABCG1 were observed in mice. In cell culture models involving lipid-loaded macrophages, we demonstrated that PHMG promotes foam cell formation by inhibiting lipid efflux in mouse alveolar macrophages. Furthermore, PHMG-induced foam cells were found to promote an increase in the release of TGF-ß1, fibronectin deposition, and collagen remodeling. In vivo interventions were subsequently implemented on mice exposed to PHMG aerosols, aiming to restore macrophage lipid efflux function. Remarkably, this intervention demonstrated the potential to retard the progression of pulmonary fibrosis. In conclusion, this study underscores the pivotal role of macrophage foaming in the pathogenesis of PHMG disinfectants-induced pulmonary fibrosis. Moreover, it provides compelling evidence to suggest that the regulation of macrophage efflux function holds promise for mitigating the progression of pulmonary fibrosis, thereby offering novel insights into the mechanisms underlying inhaled PHMG disinfectants-induced pulmonary fibrosis.


Asunto(s)
Desinfectantes , Fibrosis Pulmonar , Ratones , Animales , Fibrosis Pulmonar/metabolismo , Guanidina/toxicidad , Guanidina/metabolismo , Ratones Endogámicos C57BL , Aerosoles y Gotitas Respiratorias , Pulmón , Guanidinas/metabolismo , Macrófagos , Desinfectantes/farmacología , Lípidos
3.
Molecules ; 29(14)2024 Jul 20.
Artículo en Inglés | MEDLINE | ID: mdl-39064988

RESUMEN

Streptococcus dysgalactiae infection can cause bovine mastitis and lead to huge economic losses for the dairy industry. The abuse of antibiotics has resulted in growing drug resistance of S. dysgalactiae, which causes hard-to-treat infections. Bacteriophage lysin, as a novel antibacterial agent, has great potential for application against drug-resistant gram-positive bacteria. However, few studies have been conducted on the prophage lysin of S. dysgalactiae. In this study, we mined a novel prophage lysin, named Lys1644, from a clinical S. dysgalactiae isolate by genome sequencing and bioinformatic analysis. Lys1644 was expressed and purified, and the lytic activity, antibacterial spectrum, optimal pH and temperature, lytic activity in milk in vitro, and synergistic bacteriostasis with antibiotics were assessed. The Lys1644 prophage lysin showed high bacteriolysis activity specifically on S. dysgalactiae, which resulted in CFU 100-fold reduction in milk. Moreover, Lys1644 maintained high activity over a wide pH range (pH 5-10) and a wide temperature range (4-42 °C). Synergistic bacteriostatic experiments showed that the combination of low-dose Lys1644 (50 µg/mL) with a subinhibitory concentration of aminoglycoside antibiotics (kanamycin or spectinomycin) can completely inhibit bacterial growth, suggesting that the combination of Lys1644 and antibiotics could be an effective therapeutic strategy against S. dysgalactiae infection.


Asunto(s)
Antibacterianos , Profagos , Streptococcus , Streptococcus/efectos de los fármacos , Profagos/genética , Antibacterianos/farmacología , Antibacterianos/química , Animales , Leche/microbiología , Fagos de Streptococcus/genética , Bovinos , Mastitis Bovina/microbiología , Mastitis Bovina/tratamiento farmacológico , Concentración de Iones de Hidrógeno , Bacteriólisis/efectos de los fármacos , Infecciones Estreptocócicas/microbiología , Infecciones Estreptocócicas/tratamiento farmacológico
4.
Plant J ; 107(4): 1029-1039, 2021 08.
Artículo en Inglés | MEDLINE | ID: mdl-34056773

RESUMEN

Root growth relies on both cell division and cell elongation, which occur in the meristem and elongation zones, respectively. SCARECROW (SCR) and SHORT-ROOT (SHR) are GRAS family genes essential for root growth and radial patterning in the Arabidopsis root. Previous studies showed that SCR and SHR promote root growth by suppressing cytokinin response in the meristem, but there is evidence that SCR expressed beyond the meristem is also required for root growth. Here we report a previously unknown role for SCR in promoting cell elongation. Consistent with this, we found that the scr mutant accumulated a higher level of reactive oxygen species (ROS) in the elongation zone, which is probably due to decreased expression of peroxidase gene 3, which consumes hydrogen peroxide in a reaction leading to Casparian strip formation. When the oxidative stress response was blocked in the scr mutant by mutation in ABSCISIC ACID 2 (ABA2) or when the redox status was ameliorated by the upbeat 1 (upb1) mutant, the root became significantly longer, with longer cells and a larger and more mitotically active meristem. Remarkably, however, the stem cell and radial patterning defects in the double mutants still persisted. Since ROS and peroxidases are essential for endodermal differentiation, these results suggest that SCR plays a role in coordinating cell elongation, endodermal differentiation, redox homeostasis and oxidative stress response in the root. We also provide evidence that this role of SCR is independent of SHR, even though they function similarly in other aspects of root growth and development.


Asunto(s)
Proteínas de Arabidopsis/genética , Arabidopsis/fisiología , Raíces de Plantas/crecimiento & desarrollo , Factores de Transcripción/genética , Ácido Abscísico/metabolismo , Oxidorreductasas de Alcohol/genética , Arabidopsis/citología , Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Diferenciación Celular/genética , Regulación de la Expresión Génica de las Plantas , Homeostasis , Mutación , Oxidación-Reducción , Estrés Oxidativo/fisiología , Peroxidasa/genética , Células Vegetales , Raíces de Plantas/citología , Raíces de Plantas/genética , Plantas Modificadas Genéticamente , Especies Reactivas de Oxígeno/metabolismo , Factores de Transcripción/metabolismo
5.
Molecules ; 27(7)2022 Mar 30.
Artículo en Inglés | MEDLINE | ID: mdl-35408657

RESUMEN

Enterococci, a type of lactic acid bacteria, are widely distributed in various environments and are part of the normal flora in the intestinal tract of humans and animals. Although enterococci have gradually evolved pathogenic strains causing nosocomial infections in recent years, the non-pathogenic strains have still been widely used as probiotics and feed additives. Enterococcus can produce enterocin, which are bacteriocins considered as ribosomal peptides that kill or inhibit the growth of other microorganisms. This paper reviews the classification, synthesis, antibacterial mechanisms and applications of enterocins, and discusses the prospects for future research.


Asunto(s)
Bacteriocinas , Enterococcus faecium , Animales , Antibacterianos/farmacología , Bacteriocinas/química , Bacteriocinas/farmacología , Hidrocarburos Aromáticos con Puentes/química , Enterococcus
6.
Int J Mol Sci ; 22(2)2021 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-33467780

RESUMEN

Chemotherapy is one of the most common strategies for tumor treatment but often associated with post-therapy tumor recurrence. While chemotherapeutic drugs are known to induce tumor cell senescence, the roles and mechanisms of senescence in tumor recurrence remain unclear. In this study, we used doxorubicin to induce senescence in breast cancer cells, followed by culture of breast cancer cells with conditional media of senescent breast cancer cells (indirect co-culture) or directly with senescent breast cancer cells (direct co-culture). We showed that breast cancer cells underwent the epithelial-mesenchymal transition (EMT) to a greater extent and had stronger migration and invasion ability in the direct co-culture compared with that in the indirect co-culture model. Moreover, in the direct co-culture model, non-senescent breast cancer cells facilitated senescent breast cancer cells to escape and re-enter into the cell cycle. Meanwhile, senescent breast cancer cells regained tumor cell characteristics and underwent EMT after direct co-culture. We found that the Notch signaling was activated in both senescent and non-senescent breast cancer cells in the direct co-culture group. Notably, the EMT process of senescent and adjacent breast cancer cells was blocked upon inhibition of Notch signaling with N-[(3,5-difluorophenyl)acetyl]-l-alanyl-2-phenyl]glycine-1,1-dimethylethyl ester (DAPT) in the direct co-cultures. In addition, DAPT inhibited the lung metastasis of the co-cultured breast cancer cells in vivo. Collectively, data arising from this study suggest that both senescent and adjacent non-senescent breast cancer cells developed EMT through activating Notch signaling under conditions of intratumoral heterogeneity caused by chemotherapy, which infer the possibility that Notch inhibitors used in combination with chemotherapeutic agents may become an effective treatment strategy.


Asunto(s)
Neoplasias de la Mama/patología , Senescencia Celular , Metástasis de la Neoplasia , Receptores Notch/metabolismo , Transducción de Señal , Animales , Antineoplásicos/farmacología , Neoplasias de la Mama/metabolismo , Línea Celular Tumoral , Técnicas de Cocultivo , Doxorrubicina/farmacología , Transición Epitelial-Mesenquimal , Femenino , Humanos , Neoplasias Pulmonares/patología , Células MCF-7 , Ratones , Ratones Endogámicos BALB C , Ratones Desnudos , Recurrencia Local de Neoplasia , Trasplante de Neoplasias
7.
Molecules ; 25(20)2020 Oct 21.
Artículo en Inglés | MEDLINE | ID: mdl-33096808

RESUMEN

Mannosylerythritol lipids-A (MEL-A) is a novel biosurfactant with excellent surface activity and potential biomedical applications. In this study, we explored the antibacterial activity and the underlying mechanisms of MEL-A against the important food-borne pathogen Listeria monocytogenes. The bacterial growth and survival assays revealed a remarkable antibacterial activity of MEL-A. Since MEL-A is a biosurfactant, we examined the cell membrane integrity and morphological changes of MEL-A-treated bacteria by biochemical assays and flow cytometry analysis and electron microscopes. The results showed obvious damaging effects of MEL-A on the cell membrane and morphology. To further explore the antibacterial mechanism of MEL-A, a transcriptome analysis was performed, which identified 528 differentially expressed genes (DEGs). Gene ontology (GO) analysis revealed that the gene categories of membrane, localization and transport were enriched among the DEGs, and the analysis of the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways demonstrated significant changes in the maltodextrin ABC transporter system and stress response system. Furthermore, the growth of L. monocytogenes could also be significantly inhibited by MEL-A in milk, a model of a real food system, suggesting that MEL-A could be potentially applied as an natural antimicrobial agent to control food-borne pathogens in the food industry.


Asunto(s)
Antibacterianos/farmacología , Glucolípidos/farmacología , Listeria monocytogenes/efectos de los fármacos , Antibacterianos/química , Antibacterianos/aislamiento & purificación , Glucolípidos/química , Glucolípidos/aislamiento & purificación , Listeria monocytogenes/crecimiento & desarrollo , Pruebas de Sensibilidad Microbiana
8.
BMC Genomics ; 18(1): 893, 2017 Nov 21.
Artículo en Inglés | MEDLINE | ID: mdl-29162049

RESUMEN

BACKGROUND: The Gram-positive bacterium Enterococcus faecium is a commensal of the human gastrointestinal tract and a frequent cause of bloodstream infections in hospitalized patients. The mechanisms by which E. faecium can survive and grow in blood during an infection have not yet been characterized. Here, we identify genes that contribute to growth of E. faecium in human serum through transcriptome profiling (RNA-seq) and a high-throughput transposon mutant library sequencing approach (Tn-seq). RESULTS: We first sequenced the genome of E. faecium E745, a vancomycin-resistant clinical isolate, using a combination of short- and long read sequencing, revealing a 2,765,010 nt chromosome and 6 plasmids, with sizes ranging between 9.3 kbp and 223.7 kbp. We then compared the transcriptome of E. faecium E745 during exponential growth in rich medium and in human serum by RNA-seq. This analysis revealed that 27.8% of genes on the E. faecium E745 genome were differentially expressed in these two conditions. A gene cluster with a role in purine biosynthesis was among the most upregulated genes in E. faecium E745 upon growth in serum. The E. faecium E745 transposon mutant library was then used to identify genes that were specifically required for growth of E. faecium in serum. Genes involved in de novo nucleotide biosynthesis (including pyrK_2, pyrF, purD, purH) and a gene encoding a phosphotransferase system subunit (manY_2) were thus identified to be contributing to E. faecium growth in human serum. Transposon mutants in pyrK_2, pyrF, purD, purH and manY_2 were isolated from the library and their impaired growth in human serum was confirmed. In addition, the pyrK_2 and manY_2 mutants were tested for their virulence in an intravenous zebrafish infection model and exhibited significantly attenuated virulence compared to E. faecium E745. CONCLUSIONS: Genes involved in carbohydrate metabolism and nucleotide biosynthesis of E. faecium are essential for growth in human serum and contribute to the pathogenesis of this organism. These genes may serve as targets for the development of novel anti-infectives for the treatment of E. faecium bloodstream infections.


Asunto(s)
Enterococcus faecium/genética , Aptitud Genética , Enterococos Resistentes a la Vancomicina/genética , Animales , Sangre , Enterococcus faecium/crecimiento & desarrollo , Perfilación de la Expresión Génica , Genoma Bacteriano , Infecciones por Bacterias Grampositivas/genética , Secuenciación de Nucleótidos de Alto Rendimiento , Humanos , Análisis de Secuencia de ARN , Enterococos Resistentes a la Vancomicina/crecimiento & desarrollo , Pez Cebra
9.
Artículo en Inglés | MEDLINE | ID: mdl-28242664

RESUMEN

Enterococcus faecium is one of the primary causes of nosocomial infections. Disinfectants are commonly used to prevent infections with multidrug-resistant E. faecium in hospitals. Worryingly, E. faecium strains that exhibit tolerance to disinfectants have already been described. We aimed to identify and characterize E. faecium genes that contribute to tolerance to the disinfectant chlorhexidine (CHX). We used a transposon mutant library, constructed in a multidrug-resistant E. faecium bloodstream isolate, to perform a genome-wide screen to identify genetic determinants involved in tolerance to CHX. We identified a putative two-component system (2CS), composed of a putative sensor histidine kinase (ChtS) and a cognate DNA-binding response regulator (ChtR), which contributed to CHX tolerance in E. faecium Targeted chtR and chtS deletion mutants exhibited compromised growth in the presence of CHX. Growth of the chtR and chtS mutants was also affected in the presence of the antibiotic bacitracin. The CHX- and bacitracin-tolerant phenotype of E. faecium E1162 was linked to a unique, nonsynonymous single nucleotide polymorphism in chtR Transmission electron microscopy showed that upon challenge with CHX, the ΔchtR and ΔchtS mutants failed to divide properly and formed long chains. Normal growth and cell morphology were restored when the mutations were complemented in trans Morphological abnormalities were also observed upon exposure of the ΔchtR and ΔchtS mutants to bacitracin. The tolerance to both chlorhexidine and bacitracin provided by ChtRS in E. faecium highlights the overlap between responses to disinfectants and antibiotics and the potential for the development of cross-tolerance for these classes of antimicrobials.


Asunto(s)
Antibacterianos/farmacología , Bacitracina/farmacología , Proteínas Bacterianas/genética , Clorhexidina/farmacología , Proteínas de Unión al ADN/genética , Desinfectantes/farmacología , Enterococcus faecium/efectos de los fármacos , Enterococcus faecium/genética , Histidina Quinasa/genética , Farmacorresistencia Bacteriana Múltiple/genética , Enterococcus faecium/metabolismo , Histidina Quinasa/metabolismo , Pruebas de Sensibilidad Microbiana , Polimorfismo de Nucleótido Simple/genética
10.
J Infect Dis ; 214(2): 189-95, 2016 07 15.
Artículo en Inglés | MEDLINE | ID: mdl-26984142

RESUMEN

Enterococcus faecium is a common cause of nosocomial infections, of which infective endocarditis is associated with substantial mortality. In this study, we used a microarray-based transposon mapping (M-TraM) approach to evaluate a rat endocarditis model and identified a gene, originally annotated as "fruA" and renamed "bepA," putatively encoding a carbohydrate phosphotransferase system (PTS) permease (biofilm and endocarditis-associated permease A [BepA]), as important in infective endocarditis. This gene is highly enriched in E. faecium clinical isolates and absent in commensal isolates that are not associated with infection. Confirmation of the phenotype was established in a competition experiment of wild-type and a markerless bepA mutant in a rat endocarditis model. In addition, deletion of bepA impaired biofilm formation in vitro in the presence of 100% human serum and metabolism of ß-methyl-D-glucoside. ß-glucoside metabolism has been linked to the metabolism of glycosaminoglycans that are exposed on injured heart valves, where bacteria attach and form vegetations. Therefore, we propose that the PTS permease BepA is directly implicated in E. faecium pathogenesis.


Asunto(s)
Biopelículas/crecimiento & desarrollo , Endocarditis Bacteriana/microbiología , Endocarditis Bacteriana/fisiopatología , Enterococcus faecium/enzimología , Enterococcus faecium/fisiología , Proteínas de Transporte de Membrana/metabolismo , Factores de Virulencia/metabolismo , Animales , Elementos Transponibles de ADN , Modelos Animales de Enfermedad , Enterococcus faecium/patogenicidad , Femenino , Técnicas de Inactivación de Genes , Pruebas Genéticas , Proteínas de Transporte de Membrana/genética , Mutagénesis Insercional , Fosfotransferasas/genética , Fosfotransferasas/metabolismo , Ratas Wistar , Factores de Virulencia/genética
11.
Acta Pharmacol Sin ; 37(12): 1623-1640, 2016 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-27694907

RESUMEN

AIM: Physcion is a major bioactive ingredient in the traditional Chinese medicine Radix et Rhizoma Rhei, which has an anthraquinone chemical structure and exhibits a variety of pharmacological activities including laxative, hepatoprotective, anti-inflammatory, anti-microbial and anti-proliferative effects. In this study we investigated the effect of physcion on human nasopharyngeal carcinoma in vitro and in vivo, as well as the mechanisms underlying the anti-tumor action. METHODS: The nasopharyngeal carcinoma cell line CNE2 was treated with physcion, and cell viability was detected using MTT and colony formation assays. Flow cytometry was used to assess the cell cycle arrest, mitochondrial membrane potential loss, apoptosis, autophagy and intracellular ROS generation. Apoptotic cell death was also confirmed by a TUNEL assay. The expression of target or marker molecules was determined using Western blotting. The activity of caspase-3, 8, and 9 was detected with an ELISA kit. A xenograft murine model was used to evaluate the in vivo anti-tumor action of physcion, the mice were administered physcion (10, 20 mg·kg-1·d-1, ip) for 30 d. RESULTS: Treatment with physcion (5, 10, and 20 µmol/L) dose-dependently suppressed the cell viability and colony formation in CNE2 cells. Physcion (10 and 20 µmol/L) dose-dependently blocked cell cycle progression at G1 phase and induced both caspase-dependent apoptosis and autophagy in CNE2 cells. Furthermore, physcion treatment induced excessive ROS generation in CNE2 cells, and subsequently disrupted the miR-27a/ZBTB10 axis, resulting in repression of the transcription factor Sp1 that was involved in physcion-induced apoptosis and autophagy. Moreover, physcion-induced autophagy acted as a pro-apoptotic factor, and possibly contributed to physcion-induced apoptosis. In the xenograft murine model, administration of physcion dose-dependently suppressed the tumor growth without affecting the body weight. Furthermore, the anti-tumor effects of physcion were correlated with downregulation of Sp1 and suppression of miR-27a in the tumor tissues. CONCLUSION: Physcion induces apoptosis and autophagy in human nasopharyngeal carcinoma by targeting Sp1, which was mediated by ROS/miR-27a/ZBTB10 signaling. The results suggest that physcion is a promising candidate for the treatment of human nasopharyngeal carcinoma.


Asunto(s)
Antineoplásicos Fitogénicos/farmacología , Apoptosis/efectos de los fármacos , Autofagia/efectos de los fármacos , Emodina/análogos & derivados , Neoplasias Nasofaríngeas/tratamiento farmacológico , Animales , Antineoplásicos Fitogénicos/uso terapéutico , Línea Celular Tumoral , Emodina/farmacología , Emodina/uso terapéutico , Xenoinjertos , Humanos , Ratones , Neoplasias Nasofaríngeas/metabolismo , Trasplante de Neoplasias , Especies Reactivas de Oxígeno/metabolismo , Factor de Transcripción Sp1/genética , Factor de Transcripción Sp1/metabolismo
12.
J Bacteriol ; 197(20): 3283-93, 2015 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-26260456

RESUMEN

UNLABELLED: Enterococci are naturally tolerant to typically bactericidal cell wall-active antibiotics, meaning that their growth is inhibited but they are not killed even when exposed to a high concentration of the drug. The molecular reasons for this extraordinary tolerance are still incompletely understood. Previous work showed that resistance to killing collapsed specifically in mutants affected in superoxide dismutase (Sod) activity, arguing that bactericidal antibiotic treatment led to induction of a superoxide burst. In the present work, we show that loss of antibiotic tolerance in ΔsodA mutants of pathogenic enterococci is dependent on the energy source present during antibiotic treatment. Hexoses induce greater killing than the pentose ribose, and no killing was observed with glycerol as the energy source. These results point to glycolytic reactions as crucial for antibiotic-mediated killing of ΔsodA mutants. A transposon mutant library was constructed in Enterococcus faecalis ΔsodA mutants and screened for restored tolerance of vancomycin. Partially restored tolerance was observed in mutants with transposon integrations into intergenic regions upstream of regulators implicated in arginine catabolism. In these mutants, the arginine deiminase operon was highly upregulated. A model for the action of cell wall-active antibiotics in tolerant and nontolerant bacteria is proposed. IMPORTANCE: Antibiotic tolerance is a serious clinical concern, since tolerant bacteria have considerably increased abilities to resist killing by bactericidal drugs. Using enterococci as models for highly antibiotic-tolerant pathogens, we showed that tolerance of these bacteria is linked to their superoxide dismutase (Sod), arguing that bactericidal antibiotics induce generation of reactive oxygen species inside cells. Wild-type strains are tolerant because they detoxify these deleterious molecules by the activity of Sod, whereas Sod-deficient strains are killed. This study showed that killing depends on the energy source present during treatment and that an increase in arginine catabolism partially restored tolerance of the Sod mutants. These results are used to propose a mode-of-action model of cell wall-active antibiotics in tolerant and nontolerant bacteria.


Asunto(s)
Antibacterianos/farmacología , Arginina/metabolismo , Farmacorresistencia Bacteriana/genética , Enterococcus faecalis/enzimología , Superóxido Dismutasa/metabolismo , Metabolismo de los Hidratos de Carbono , Elementos Transponibles de ADN , Enterococcus faecalis/efectos de los fármacos , Enterococcus faecalis/genética , Enterococcus faecalis/metabolismo , Regulación Bacteriana de la Expresión Génica/fisiología , Regulación Enzimológica de la Expresión Génica , Pruebas de Sensibilidad Microbiana , Mutagénesis Insercional , Mutación , Penicilinas/farmacología , Superóxido Dismutasa/genética , Vancomicina/farmacología
13.
PLoS Genet ; 8(6): e1002804, 2012 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-22761597

RESUMEN

Enterococcus faecium has become a nosocomial pathogen of major importance, causing infections that are difficult to treat owing to its multi-drug resistance. In particular, resistance to the ß-lactam antibiotic ampicillin has become ubiquitous among clinical isolates. Mutations in the low-affinity penicillin binding protein PBP5 have previously been shown to be important for ampicillin resistance in E. faecium, but the existence of additional resistance determinants has been suggested. Here, we constructed a high-density transposon mutant library in E. faecium and developed a transposon mutant tracking approach termed Microarray-based Transposon Mapping (M-TraM), leading to the identification of a compendium of E. faecium genes that contribute to ampicillin resistance. These genes are part of the core genome of E. faecium, indicating a high potential for E. faecium to evolve towards ß-lactam resistance. To validate the M-TraM results, we adapted a Cre-lox recombination system to construct targeted, markerless mutants in E. faecium. We confirmed the role of four genes in ampicillin resistance by the generation of targeted mutants and further characterized these mutants regarding their resistance to lysozyme. The results revealed that ddcP, a gene predicted to encode a low-molecular-weight penicillin binding protein with D-alanyl-D-alanine carboxypeptidase activity, was essential for high-level ampicillin resistance. Furthermore, deletion of ddcP sensitized E. faecium to lysozyme and abolished membrane-associated D,D-carboxypeptidase activity. This study has led to the development of a broadly applicable platform for functional genomic-based studies in E. faecium, and it provides a new perspective on the genetic basis of ampicillin resistance in this organism.


Asunto(s)
Resistencia a la Ampicilina/genética , Infección Hospitalaria , Enterococcus faecium , Proteínas de Unión a las Penicilinas/genética , Ampicilina/farmacología , Proliferación Celular/efectos de los fármacos , Infección Hospitalaria/genética , Infección Hospitalaria/microbiología , Elementos Transponibles de ADN/genética , Enterococcus faecium/genética , Enterococcus faecium/patogenicidad , Regulación Bacteriana de la Expresión Génica/efectos de los fármacos , Genoma Bacteriano , Humanos , Muramidasa/farmacología , Mutación , Análisis de Secuencia por Matrices de Oligonucleótidos , Proteínas de Unión a las Penicilinas/aislamiento & purificación , Proteínas de Unión a las Penicilinas/metabolismo , D-Ala-D-Ala Carboxipeptidasa de Tipo Serina/genética , D-Ala-D-Ala Carboxipeptidasa de Tipo Serina/aislamiento & purificación , D-Ala-D-Ala Carboxipeptidasa de Tipo Serina/metabolismo
14.
PLoS Pathog ; 8(8): e1002834, 2012.
Artículo en Inglés | MEDLINE | ID: mdl-22876178

RESUMEN

Oxidative stress serves as an important host/environmental signal that triggers a wide range of responses in microorganisms. Here, we identified an oxidative stress sensor and response regulator in the important multidrug-resistant nosocomial pathogen Enterococcus faecium belonging to the MarR family and called AsrR (antibiotic and stress response regulator). The AsrR regulator used cysteine oxidation to sense the hydrogen peroxide which results in its dissociation to promoter DNA. Transcriptome analysis showed that the AsrR regulon was composed of 181 genes, including representing functionally diverse groups involved in pathogenesis, antibiotic and antimicrobial peptide resistance, oxidative stress, and adaptive responses. Consistent with the upregulated expression of the pbp5 gene, encoding a low-affinity penicillin-binding protein, the asrR null mutant was found to be more resistant to ß-lactam antibiotics. Deletion of asrR markedly decreased the bactericidal activity of ampicillin and vancomycin, which are both commonly used to treat infections due to enterococci, and also led to over-expression of two major adhesins, acm and ecbA, which resulted in enhanced in vitro adhesion to human intestinal cells. Additional pathogenic traits were also reinforced in the asrR null mutant including greater capacity than the parental strain to form biofilm in vitro and greater persistance in Galleria mellonella colonization and mouse systemic infection models. Despite overexpression of oxidative stress-response genes, deletion of asrR was associated with a decreased oxidative stress resistance in vitro, which correlated with a reduced resistance to phagocytic killing by murine macrophages. Interestingly, both strains showed similar amounts of intracellular reactive oxygen species. Finally, we observed a mutator phenotype and enhanced DNA transfer frequencies in the asrR deleted strain. These data indicate that AsrR plays a major role in antimicrobial resistance and adaptation for survival within the host, thereby contributes importantly to the opportunistic traits of E. faecium.


Asunto(s)
Proteínas Bacterianas/metabolismo , Enterococcus faecium/patogenicidad , Infecciones por Bacterias Grampositivas/metabolismo , Factores de Transcripción/metabolismo , Resistencia betalactámica , Animales , Antibacterianos/farmacología , Proteínas Bacterianas/genética , Enterococcus faecium/genética , Enterococcus faecium/metabolismo , Infecciones por Bacterias Grampositivas/tratamiento farmacológico , Infecciones por Bacterias Grampositivas/genética , Humanos , Peróxido de Hidrógeno/farmacología , Macrófagos Peritoneales/metabolismo , Macrófagos Peritoneales/microbiología , Masculino , Ratones , Ratones Endogámicos BALB C , Oxidantes/farmacología , Oxidación-Reducción/efectos de los fármacos , Carácter Cuantitativo Heredable , Factores de Transcripción/genética , beta-Lactamas/farmacología
15.
J Infect Dis ; 207(11): 1780-6, 2013 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-23447698

RESUMEN

Intestinal colonization by antibiotic-resistant Enterococcus faecium is the first step in a process that can lead to infections in hospitalized patients. By comparative genome analysis and subsequent polymerase chain reaction screening, we identified a locus that encodes a putative phosphotransferase system (PTS). The PTS locus was widespread in isolates from hospital outbreaks of infection (84.2%) and nonoutbreak clinical infections (66.0%) but absent from human commensal isolates. Deletion of pstD, which is predicted to encode the enzyme IID subunit of this PTS, significantly impaired the ability of E. faecium to colonize the murine intestinal tract during antibiotic treatment. This is the first description of a determinant that contributes to intestinal colonization in clinical E. faecium strains.


Asunto(s)
Antibacterianos/administración & dosificación , Enterococcus faecium/genética , Enterococcus faecium/patogenicidad , Tracto Gastrointestinal/microbiología , Fosfotransferasas/genética , Factores de Virulencia/genética , Animales , Portador Sano/microbiología , Modelos Animales de Enfermedad , Enterococcus faecium/aislamiento & purificación , Eliminación de Gen , Infecciones por Bacterias Grampositivas/microbiología , Humanos , Masculino , Ratones , Ratones Endogámicos BALB C
16.
Front Psychiatry ; 15: 1428028, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-39119078

RESUMEN

Background: Post-stroke depression (PSD) is a prevalent psychiatric disorder affecting about one-third of stroke survivors, significantly hindering recovery and quality of life. PSD also imposes a substantial burden on caregivers and healthcare systems. Aromatherapy has shown promise in alleviating depression, anxiety, and sleep disorders. This pilot randomized controlled trial aims to assess the feasibility and preliminary efficacy of mixed herb aromatherapy in treating PSD. Feasibility outcomes encompass recruitment, intervention adherence, assessment completion and safety assessment. Secondary outcomes include evaluations of depression, anxiety, cognitive function, sleep quality, quality of life, and brain function using EEG and fNIRS. Methods: This single-blind pilot randomized controlled trial will be conducted at the Second Rehabilitation Hospital of Shanghai, enrolling ninety-nine post-stroke patients with PSD. Participants will be randomized into three groups: a Non-Active Control Group receiving standardized rehabilitation therapy, a CBT Group receiving conventional rehabilitation with bi-weekly CBT sessions, and an Aromatherapy Group receiving conventional rehabilitation with daily aromatic inhalation sessions. Interventions will last for four weeks, with efficacy assessed at baseline, post-intervention, and one month post-intervention. Rating scales will be used to measure changes in depression, sleep quality, cognitive function, and quality of life. EEG and fNIRS will specifically be used to measure changes in cerebral cortex activity and their correlations with depression. Feasibility will be evaluated through recruitment, intervention adherence, assessment completion and safety assessment. Discussion: This pilot study highlights the potential of mixed herb aromatherapy inhalation for treating PSD, addressing limitations of CBT by promoting self-management. While demonstrating feasibility through recruitment, adherence, assessment completion and safety assessment, the study also acknowledges limitations such as unequal intervention times, the lack of physical function data. And the use of culturally relevant plant powders may enhance compliance but limits generalizability. Despite these constraints, the study provides valuable preliminary data and insights into the mechanisms of aromatherapy, encouraging further research and development of effective PSD treatments.

17.
Front Public Health ; 12: 1196248, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38379678

RESUMEN

Background: Bisphenol A (BPA) is an oil-derived, large-market volume chemical with endocrine disrupting properties and reproductive toxicity. Moreover, BPA is frequently used in food contact materials, has been extensively researched recently, and widespread exposure in the general population has been reported worldwide. However, national information on BPA levels in general Chinese people is lacking. Methods: This study collected and analyzed 145 (104 in urine and 41 in serum) research articles published between 2004 and 2021 to reflect the BPA internal exposure levels in Chinese populations. The Monte Carlo simulation method is employed to analyze and estimate the data in order to rectify the deviation caused by a skewed distribution. Results: Data on BPA concentrations in urine and serum were collected from 2006 to 2019 and 2004 to 2019, respectively. Urinary BPA concentrations did not vary significantly until 2017, with the highest concentration occurring from 2018 to 2019 (2.90 ng/mL). The serum BPA concentration decreased to the nadir of 1.07 ng/mL in 2011 and gradually increased to 2.54 ng/mL. Nationally, 18 provinces were studied, with Guangdong (3.50 ng/mL), Zhejiang (2.57 ng/mL), and Fujian (2.15 ng/mL) having the highest urine BPA levels. Serum BPA was investigated in 15 provinces; Jiangsu (9.14 ng/mL) and Shandong (5.80 ng/mL) were relatively high. The results also indicated that males' urine and serum BPA levels were higher than females, while the BPA levels in children were also higher than in adults (p < 0.001). Furthermore, the volume of garbage disposal (r = 0.39, p < 0.05), household sewage (r = 0.34, p < 0.05), and waste incineration content (r = 0.35, p < 0.05) exhibited a strong positive connection with urine BPA levels in Chinese individuals. Conclusion: Despite using a data consolidation approach, our study found that the Chinese population was exposed to significant amounts of BPA, and males having a higher level than females. Besides, the levels of BPA exposure are influenced by the volume of garbage disposal, household sewage, and waste incineration content.


Asunto(s)
Compuestos de Bencidrilo , Pueblos del Este de Asia , Fenoles , Aguas del Alcantarillado , Adulto , Niño , Femenino , Humanos , Masculino , Compuestos de Bencidrilo/sangre , Compuestos de Bencidrilo/orina , China , Fenoles/sangre , Fenoles/orina , Factores de Riesgo
18.
Heliyon ; 10(7): e28879, 2024 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-38596075

RESUMEN

Cadmium (Cd), a ubiquitous heavy metal, exists in numerous environmental matrices and has severe adverse effects on various human organs and tissues. This research evaluates blood and urine Cd levels in the Chinese population through data mining using Monte Carlo simulation (MCS). A total of 168 scientific studies (120 on urine and 48 on blood) published between January 1980 and December 2020, reflecting a population of 109,743 individuals in China, were included in the study. The results indicate that the blood and urine Cd levels in the Chinese population exhibited a peak from 1990 to 1995 and remained stable after 1995, averaging 1.21 µg/L of blood Cd (BCd) and 0.61 µg/L of urine Cd (UCd). The spatial trend of Cd levels varied significantly. Shandong, Zhejiang, Heilongjiang, and Guangdong provinces were identified as the top provinces with high Cd levels, which were related to factors such as tobacco sales, E-waste amounts, and contaminated rice. Additionally, the study highlights that BCd concentrations are highest among preschool-aged individuals, whereas school-age and adolescent groups exhibit the lowest levels. However, no significant difference existed among the different age groups. Males showed significantly higher Cd levels than females in the general population. Moreover, exposure to smoking, drinking, and staple food preferences had an impact on Cd levels. Furthermore, this comprehensive study, using biological monitoring and data mining, provides valuable information on Cd pollution levels in the Chinese population. It presents a statistical analysis that can aid decision-makers in implementing effective measures to control potential Cd pollution and improve the health of vulnerable populations.

19.
J Cancer Res Clin Oncol ; 150(9): 424, 2024 Sep 19.
Artículo en Inglés | MEDLINE | ID: mdl-39297944

RESUMEN

PURPOSE: This study aimed to investigate the effect of MYO3B on endometrial cancer (EC) proliferation and invasion. METHODS: The expression of MYO3B in EC tissues and cells was analyzed using TCGA database, immunohistochemical staining, real-time PCR, and western blot (WB). Cell proliferation was detected by CCK8, Annexin V-APC/PI flow cytometry was used to detect apoptosis, intracellular calcium ion (Ca2+) was detected by flow cytometry with Fluo-4 AM fluorescent probe, cell migration by scratch assay, and cell invasion by Transwell assay, and the expression of proteins related to Ca2+ homeostasis and RhoA/ROCK1 signaling pathway was detected by WB and immunofluorescence staining. RESULTS: The expression of MYO3B was an influential factor in EC recurrence, and the expression of MYO3B was significantly up-regulated in EC tissues and cells, but down-regulated in KLE cells, and MYO3B knockdown inhibited the proliferation, migration, and invasion ability of EC cells and promoted apoptosis, suggesting that MYO3B plays a tumor-promoting role in EC. Furthermore, MYO3B knockdown decreased Ca2+ concentration in EC cells and the RhoA/ROCK1 signaling pathway was inhibited, and the effect of MYO3B knockdown on RhoA/ROCK1 signaling was reversed by treatment with the Calmodulin agonist CALP-2, and the effects of MYO3B knockdown on cell proliferation, migration, and invasion were reversed after treatment with the RhoA agonist U-46,619. CONCLUSION: MYO3B promotes the proliferation and migration of endometrial cancer cells via Ca2+-RhoA/ROCK1 signaling pathway. High expression of MYO3B may be a biomarker for EC metastasis.


Asunto(s)
Calcio , Proliferación Celular , Progresión de la Enfermedad , Neoplasias Endometriales , Transducción de Señal , Quinasas Asociadas a rho , Proteína de Unión al GTP rhoA , Humanos , Femenino , Quinasas Asociadas a rho/metabolismo , Quinasas Asociadas a rho/genética , Neoplasias Endometriales/patología , Neoplasias Endometriales/metabolismo , Neoplasias Endometriales/genética , Proteína de Unión al GTP rhoA/metabolismo , Calcio/metabolismo , Movimiento Celular , Apoptosis , Línea Celular Tumoral , Invasividad Neoplásica
20.
Chemosphere ; 362: 142564, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-38885762

RESUMEN

Atmospheric pollution has been demonstrated to be associated with ocular surface diseases characterized by corneal epithelial damage, including impaired barrier function and squamous metaplasia. However, the specific mechanisms underlying the impact of atmospheric pollution on corneal damage are still unknow. To address this gap in knowledge, we conducted a study using a whole-body exposure system to investigate the detrimental effects of traffic-related air pollution, specifically diesel exhaust (DE), on corneal epithelium in C57BL/6 mice over a 28-day period. Following DE exposure, the pathological alterations in corneal epithelium, including significant increase in corneal thickness and epithelial stratification, were observed in mice. Additionally, exposure to DE was also shown to disrupt the barrier functions of corneal epithelium, leading to excessive proliferation of basal cells and even causing squamous metaplasia in corneal epithelium. Further studies have found that the activation of yes-associated protein (YAP), characterized by nuclear translocation, may play a significant role in DE-induced corneal squamous metaplasia. In vitro assays confirmed that DE exposure triggered the YAP/ß-catenin pathway, resulting in squamous metaplasia and destruction of barrier functions. These findings provide the preliminary evidence that YAP activation is one of the mechanisms of the damage to corneal epithelium caused by traffic-related air pollution. These findings contribute to the knowledge base for promoting eye health in the context of atmospheric pollution.


Asunto(s)
Contaminantes Atmosféricos , Epitelio Corneal , Metaplasia , Ratones Endogámicos C57BL , Emisiones de Vehículos , Proteínas Señalizadoras YAP , Emisiones de Vehículos/toxicidad , Animales , Epitelio Corneal/efectos de los fármacos , Epitelio Corneal/patología , Ratones , Contaminantes Atmosféricos/toxicidad , Masculino , beta Catenina/metabolismo , Proliferación Celular/efectos de los fármacos
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA