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1.
Appl Opt ; 62(28): 7544-7548, 2023 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-37855525

RESUMEN

In a stretcher, the surface distortion of the optical elements can introduce spectral phase modulations into the laser, which can affect the laser's signal-to-noise ratio. In this paper, by combining ray tracing methods and angular spectrum diffraction methods, the impact of the mid-frequency surface distortion of the optical elements in an cylindrical Offner stretcher on the far-field signal-to-noise ratio of the laser is simulated. The results show that reducing the spatial chirp on the convex cylindrical mirror can effectively improve the far-field signal-to-noise ratio of the laser, and two methods to improve the far-field signal-to-noise ratio are presented.

2.
Nat Chem Biol ; 15(1): 42-50, 2019 01.
Artículo en Inglés | MEDLINE | ID: mdl-30397328

RESUMEN

Expression of programmed cell death 1 (PD-1) ligand 1 (PD-L1) protects tumor cells from T cell-mediated immune surveillance, and immune checkpoint blockade (ICB) therapies targeting PD-1 and PD-L1 have exhibited significant clinical benefits. However, the relatively low response rate and observed ICB resistance highlight the need to understand the molecular regulation of PD-L1. Here we show that HIP1R targets PD-L1 to lysosomal degradation to alter T cell-mediated cytotoxicity. HIP1R physically interacts with PD-L1 and delivers PD-L1 to the lysosome through a lysosomal targeting signal. Depletion of HIP1R in tumor cells caused PD-L1 accumulation and suppressed T cell-mediated cytotoxicity. A rationally designed peptide (PD-LYSO) incorporating the lysosome-sorting signal and the PD-L1-binding sequence of HIP1R successfully depleted PD-L1 expression in tumor cells. Our results identify the molecular machineries governing the lysosomal degradation of PD-L1 and exemplify the development of a chimeric peptide for targeted degradation of PD-L1 as a crucial anticancer target.


Asunto(s)
Antígeno B7-H1/metabolismo , Lisosomas/metabolismo , Linfocitos T Citotóxicos/metabolismo , Proteínas de Transporte Vesicular/metabolismo , Proteínas Adaptadoras Transductoras de Señales , Sitios de Unión , Proteínas de Unión al Calcio/metabolismo , Proteínas de Ciclo Celular/metabolismo , Línea Celular Tumoral , Complejos de Clasificación Endosomal Requeridos para el Transporte/metabolismo , Humanos , Lisosomas/efectos de los fármacos , Proteínas de Microfilamentos , Péptidos/farmacología , Receptor de Muerte Celular Programada 1/metabolismo , Dominios Proteicos , Señales de Clasificación de Proteína , Proteínas de Transporte Vesicular/genética
3.
BMC Microbiol ; 19(1): 104, 2019 05 22.
Artículo en Inglés | MEDLINE | ID: mdl-31117936

RESUMEN

BACKGROUND: Vitamin B1 (VB1) is a crucial dietary nutrient and essential cofactor for several key enzymes in the regulation of cellular and metabolic processes, and more importantly in the activation of immune system. To date, the precise role of VB1 in Mycobacterium tuberculosis remains to be fully understood. RESULTS: In this study, the transcriptional and metabolic profiles of VB1-treated Mycobacterium. bovis BCG were analyzed by RNA-sequencing and LC-MS (Liquid chromatography coupled to mass spectrometry). The selection of BCG strain was based on its common physiological features shared with M. tuberculosis. The results of cell growth assays demonstrated that VB1 inhibited the BCG growth rate in vitro. Transcriptomic analysis revealed that the expression levels of genes related to fatty acid metabolism, cholesterol metabolism, glycolipid catabolism, DNA replication, protein translation, cell division and cell wall formation were significantly downregulated in M. bovis BCG treated with VB1. In addition, the metabolomics LC-MS data indicated that most of the amino acids and adenosine diphosphate (ADP) were decreased in M. bovis BCG strain after VB1 treatment. CONCLUSIONS: This study provides the molecular and metabolic bases to understand the impacts of VB1 on M.bovis BCG.


Asunto(s)
Proteínas Bacterianas/genética , Metaboloma/efectos de los fármacos , Mycobacterium bovis/crecimiento & desarrollo , Tiamina/farmacología , Cromatografía Liquida , Perfilación de la Expresión Génica/métodos , Regulación Bacteriana de la Expresión Génica/efectos de los fármacos , Espectrometría de Masas , Metabolómica/métodos , Mycobacterium bovis/química , Mycobacterium bovis/efectos de los fármacos , Mycobacterium bovis/genética , Análisis de Secuencia de ARN
4.
Gut ; 64(1): 37-48, 2015 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-24717932

RESUMEN

OBJECTIVE: Octamer transcription factor 1 (OCT1) was found to be expressed in intestinal metaplasia and gastric cancer (GC), but the exact roles of OCT1 in GC remain unclear. The objective of this study was to determine the functional and prognostic implications of OCT1 in GC. DESIGN: Expression of OCT1 was examined in paired normal and cancerous gastric tissues and the prognostic significance of OCT1 was analysed by univariate and multivariate survival analyses. The functions of OCT1 on synbindin expression and extracellular signal-regulated kinase (ERK) phosphorylation were studied in vitro and in xenograft mouse models. RESULTS: The OCT1 gene is recurrently amplified and upregulated in GC. OCT1 overexpression and amplification are associated with poor survival in patients with GC and the prognostic significance was confirmed by independent patient cohorts. Combining OCT1 overexpression with American Joint Committee on Cancer staging improved the prediction of survival in patients with GC. High expression of OCT1 associates with activation of the ERK mitogen-activated protein kinase signalling pathway in GC tissues. OCT1 functions by transactivating synbindin, which binds to ERK DEF domain and facilitates ERK phosphorylation by MEK. OCT1-synbindin signalling results in the activation of ERK substrates ELK1 and RSK, leading to increased cell proliferation and invasion. Immunofluorescent study of human GC tissue samples revealed strong association between OCT1 protein level and synbindin expression/ERK phosphorylation. Upregulation of OCT1 in mouse xenograft models induced synbindin expression and ERK activation, leading to accelerated tumour growth in vivo. CONCLUSIONS: OCT1 is a driver of synbindin-mediated ERK signalling and a promising marker for the prognosis and molecular subtyping of GC.


Asunto(s)
Quinasas MAP Reguladas por Señal Extracelular/fisiología , Sistema de Señalización de MAP Quinasas/fisiología , Proteínas del Tejido Nervioso/fisiología , Transportador 1 de Catión Orgánico/fisiología , Neoplasias Gástricas/fisiopatología , Proteínas de Transporte Vesicular/fisiología , Animales , Ratones , Pronóstico
5.
Microb Pathog ; 83-84: 6-11, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-25819881

RESUMEN

To construct a novel live, attenuated Salmonella vaccine, the lon, cpxR and cpdB genes were deleted from a wild-type Salmonella enterica serovar Enteritidis-6 (SM-6) strain using the phage λ Red homologous recombination system, resulting in SM-△CpxR, SM-△C/Lon and SM-△C/L/CpdB. The growth curves of strain SM-△C/Lon grew more rapidly than the other strains and had OD 600 values higher than the other strains starting at the 4 h time point. The growth curves of strain SM-△C/L/CpdB were relatively flat. The colonization time of SM-△C/L/CpdB is about 8-10 days. Deleting the lon/cpxR/cpdB (SM-6) genes resulted in an approximate 10(3)-fold attenuation in virulence assessed by the analysis of the LD50 of specific pathogen-free (SPF) chicks. This result indicated that the deletion of the lon, cpxR and cpdB genes induced significant virulence attenuation. The protective effects of SM-△C/L/CpdB vaccination in SPF chicks against 5 × 10(9) colony forming units (CFU) of S. Enteritidis were resulted from the induction of an effective immune response. These findings demonstrate the potential of mutant SM-△C/L/CpdB to be used as an effective vaccine.


Asunto(s)
Salmonelosis Animal/prevención & control , Vacunas contra la Salmonella/inmunología , Salmonella enteritidis/inmunología , Animales , Animales Recién Nacidos , Proteínas Bacterianas/genética , Pollos , Eliminación de Gen , Dosificación Letal Mediana , Recombinación Genética , Salmonelosis Animal/inmunología , Vacunas contra la Salmonella/administración & dosificación , Vacunas contra la Salmonella/genética , Salmonella enteritidis/genética , Salmonella enteritidis/crecimiento & desarrollo , Salmonella enteritidis/patogenicidad , Vacunas Atenuadas/administración & dosificación , Vacunas Atenuadas/genética , Vacunas Atenuadas/inmunología , Virulencia , Factores de Virulencia/genética
6.
Plasmid ; 82: 10-6, 2015 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-26123974

RESUMEN

To investigate whether plasmid-free cells of pathogenic Escherichia coli can be isolated by disrupting a single gene in an endogenous plasmid without further treatment, the effect of the disruption of partitioning genes on the inheritance of the endogenous plasmid pUTI89 of the uropathogenic E. coli strain UTI89 was studied. We found that mutation of parB, which encodes a type Ib partitioning protein, could cause loss of the endogenous plasmid at a ratio of about 1%. Clones derived from parB mutants, identified by antibiotic sensitivity, were all plasmid free. Plasmid instability caused by the parB mutation was found to correlate with a negative effect on host cell growth. Thus, in this pathogenic E. coli, an endogenous plasmid as large as 114 kbp could be cured effectively by targeting a single type Ib partitioning gene followed by passaging, which may facilitate further investigations on the function of endogenous plasmids in their natural hosts.


Asunto(s)
ADN Primasa/genética , Proteínas de Escherichia coli/genética , Escherichia coli/genética , Plásmidos/genética , Antibacterianos/farmacología , Elementos Transponibles de ADN/genética , ADN Bacteriano/genética , Farmacorresistencia Bacteriana/genética , Escherichia coli/crecimiento & desarrollo , Genes Bacterianos/genética , Kanamicina/farmacología , Mutación/genética
7.
Biomacromolecules ; 16(6): 1827-36, 2015 Jun 08.
Artículo en Inglés | MEDLINE | ID: mdl-25961760

RESUMEN

n-Heptyl α-d-mannose (HM) is a nanomolar antagonist of FimH, a virulence factor of E. coli. Herein we report on the construction of multivalent HM-based glycopolymers as potent antiadhesives of type 1 piliated E. coli. We investigate glycopolymer/FimH and glycopolymer/bacteria interactions and show that HM-based glycopolymers efficiently inhibit bacterial adhesion and disrupt established cell-bacteria interactions in vitro at very low concentration (0.1 µM on a mannose unit basis). On a valency-corrected basis, HM-based glycopolymers are, respectively, 10(2) and 10(6) times more potent than HM and d-mannose for their capacity to disrupt the binding of adherent-invasive E. coli to T84 intestinal epithelial cells. Finally, we demonstrate that the antiadhesive capacities of HM-based glycopolymers are preserved ex vivo in the colonic loop of a transgenic mouse model of Crohn's disease. All together, these results underline the promising scope of HM-based macromolecular ligands for the antiadhesive treatment of E. coli induced inflammatory bowel diseases.


Asunto(s)
Proteínas Fimbrias/antagonistas & inhibidores , Mucosa Intestinal/efectos de los fármacos , Polisacáridos Bacterianos/farmacología , Adhesinas de Escherichia coli , Animales , Adhesión Celular/efectos de los fármacos , Escherichia coli/patogenicidad , Células HeLa , Heptanol/química , Humanos , Enfermedades Inflamatorias del Intestino/microbiología , Manosa/química , Ratones , Polisacáridos Bacterianos/química
8.
Ecotoxicol Environ Saf ; 120: 418-27, 2015 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-26122735

RESUMEN

The ecotoxicological effects of pyraoxystrobin, a novel strobilurin fungicide, were studied using outdoor freshwater microcosms and the species sensitivity distribution approach. The microcosms were treated with pyraoxystrobin at concentrations of 0, 1.0, 3.0, 10, 30 and 100µg/L. Species sensitivity distribution (SSD) curves were constructed by means of acute toxicity data using the BurrliOZ model for fourteen representatives of sensitive invertebrates, algae and fish and eleven taxa of invertebrates and algae, respectively. The responses of zooplankton, phytoplankton and physical and chemical endpoints in microcosms were studied. Zooplankton, especially Sinodiaptomus sarsi was the most sensitive to pyraoxystrobin exposure in the microcosms. Short-term toxic effects (<8 weeks) on zooplankton occurred in 1µg/L treatment group. The duration of toxic effects on S. sarsi could not be evaluated within the initial 56 days. Significant long-term toxic effects were observed at 10, 30 and 100µg/L (>281 days) for S. sarsi and the zooplankton community. Based on the results obtained from the organisms in the microcosm system, 1µg/L was recommended as the NOEAEC (no observed ecologically adverse effect concentration). Also, 0.33µg/L was derived as the Regulatory Acceptable Concentration based on the ecological recovery option (ERO-RAC) of pyraoxystrobin. For all fourteen tested species, the median HC5 (hazardous concentration affecting 5% of species) was 0.86µg/L, and the lower limit HC5 (LL-HC5) was 0.39µg/L. For the eleven taxa of invertebrates and algae tested, the median HC5 was 1.1µg/L, and the LL-HC5 was 0.26µg/L. The present study positively contributes to the suggestion of adequately using acute L(E)C50-based HC5/ LL-HC5 for deriving protective concentrations for strobilurin fungicides, and it should be valuable for full comprehension of the potential toxicity of pyraoxystrobin in aquatic ecosystems.


Asunto(s)
Antifúngicos/toxicidad , Copépodos/efectos de los fármacos , Acrilatos/análisis , Acrilatos/toxicidad , Animales , Fenómenos Químicos , Copépodos/metabolismo , Cyprinidae/metabolismo , Daphnia/efectos de los fármacos , Daphnia/metabolismo , Ácidos Grasos Insaturados/análisis , Ácidos Grasos Insaturados/toxicidad , Agua Dulce/química , Sedimentos Geológicos/química , Dosificación Letal Mediana , Metacrilatos/análisis , Metacrilatos/toxicidad , Penaeidae/efectos de los fármacos , Penaeidae/metabolismo , Fitoplancton/efectos de los fármacos , Fitoplancton/metabolismo , Pirazoles/análisis , Pirazoles/toxicidad , Medición de Riesgo , Especificidad de la Especie , Estrobilurinas , Pruebas de Toxicidad , Contaminantes Químicos del Agua/análisis , Contaminantes Químicos del Agua/toxicidad , Pez Cebra/metabolismo , Zooplancton/efectos de los fármacos , Zooplancton/metabolismo
9.
Front Microbiol ; 15: 1329715, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38357346

RESUMEN

Mycobacterium tuberculosis (Mtb) is a bacterial pathogen that can endure for long periods in an infected patient, without causing disease. There are a number of virulence factors that increase its ability to invade the host. One of these factors is lipolytic enzymes, which play an important role in the pathogenic mechanism of Mtb. Bacterial lipolytic enzymes hydrolyze lipids in host cells, thereby releasing free fatty acids that are used as energy sources and building blocks for the synthesis of cell envelopes, in addition to regulating host immune responses. This review summarizes the relevant recent studies that used in vitro and in vivo models of infection, with particular emphasis on the virulence profile of lipolytic enzymes in Mtb. A better understanding of these enzymes will aid the development of new treatment strategies for TB. The recent work done that explored mycobacterial lipolytic enzymes and their involvement in virulence and pathogenicity was highlighted in this study. Lipolytic enzymes are expected to control Mtb and other intracellular pathogenic bacteria by targeting lipid metabolism. They are also potential candidates for the development of novel therapeutic agents.

10.
Front Cell Infect Microbiol ; 14: 1360880, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38529472

RESUMEN

Metal ions are essential trace elements for all living organisms and play critical catalytic, structural, and allosteric roles in many enzymes and transcription factors. Mycobacterium tuberculosis (MTB), as an intracellular pathogen, is usually found in host macrophages, where the bacterium can survive and replicate. One of the reasons why Tuberculosis (TB) is so difficult to eradicate is the continuous adaptation of its pathogen. It is capable of adapting to a wide range of harsh environmental stresses, including metal ion toxicity in the host macrophages. Altering the concentration of metal ions is the common host strategy to limit MTB replication and persistence. This review mainly focuses on transcriptional regulatory proteins in MTB that are involved in the regulation of metal ions such as iron, copper and zinc. The aim is to offer novel insights and strategies for screening targets for TB treatment, as well as for the development and design of new therapeutic interventions.


Asunto(s)
Mycobacterium tuberculosis , Tuberculosis , Humanos , Mycobacterium tuberculosis/genética , Mycobacterium tuberculosis/metabolismo , Tuberculosis/microbiología , Metales/metabolismo , Homeostasis/fisiología , Factores de Transcripción/genética , Factores de Transcripción/metabolismo , Iones/metabolismo
11.
Sci Total Environ ; 952: 175878, 2024 Nov 20.
Artículo en Inglés | MEDLINE | ID: mdl-39222821

RESUMEN

Hydroxy-polycyclic aromatic hydrocarbons (OH-PAHs) are a growing worldwide concern because of their persistence, ubiquity, and toxicity. Nonetheless, research on the toxicological mechanisms of OH-PAHs remains sparse, particularly concerning the risk of liver cancer. This study evaluated the effects of OH-PAHs on disrupting estrogen receptor α (ERα) and subsequently facilitating hepatocellular invasion and metastasis. Results revealed that all six OH-PAHs exhibited ERα agonistic activities at noncytotoxic levels, which were partially validated using molecular docking (MD) and molecular dynamics simulations (MDS). Furthermore, OH-PAHs with ERα agonistic properties stimulated a concentration-dependent increase in the migration and invasion of HepG2 cells. In addition, they disturbed the expression of target genes associated with epithelial-mesenchymal transition (EMT) and extracellular matrix (ECM), and the invasion effects were significantly reversed by adding an ERα antagonist. Our results suggest an essential role of ERα in the metastasis of liver cancer cells induced by OH-PAHs and emphasize their potential ecological and health hazards.


Asunto(s)
Receptor alfa de Estrógeno , Neoplasias Hepáticas , Hidrocarburos Policíclicos Aromáticos , Receptor alfa de Estrógeno/metabolismo , Humanos , Neoplasias Hepáticas/inducido químicamente , Células Hep G2 , Hidrocarburos Policíclicos Aromáticos/toxicidad , Transición Epitelial-Mesenquimal/efectos de los fármacos , Simulación del Acoplamiento Molecular , Movimiento Celular/efectos de los fármacos
12.
Front Cell Infect Microbiol ; 14: 1382145, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38736748

RESUMEN

Carbapenem-resistant Acinetobacter baumannii (CRAB) has become a new threat in recent years, owing to its rapidly increasing resistance to antibiotics and new effective therapies are needed to combat this pathogen. Phage therapy is considered to be the most promising alternative for treating CRAB infections. In this study, a novel phage, Ab_WF01, which can lyse clinical CRAB, was isolated and characterized from hospital sewage. The multiplicity of infection, morphology, one-step growth curve, stability, sensitivity, and lytic activity of the phage were also investigated. The genome of phage Ab_WF01 was 41, 317 bp in size with a GC content of 39.12% and encoded 51 open reading frames (ORFs). tRNA, virulence, and antibiotic resistance genes were not detected in the phage genome. Comparative genomic and phylogenetic analyses suggest that phage Ab_WF01 is a novel species of the genus Friunavirus, subfamily Beijerinckvirinae, and family Autographiviridae. The in vivo results showed that phage Ab_WF01 significantly increased the survival rate of CRAB-infected Galleria mellonella (from 0% to 70% at 48 h) and mice (from 0% to 60% for 7 days). Moreover, after day 3 post-infection, phage Ab_WF01 reduced inflammatory response, with strongly ameliorated histological damage and bacterial clearance in infected tissue organs (lungs, liver, and spleen) in mouse CRAB infection model. Taken together, these results show that phage Ab_WF01 holds great promise as a potential alternative agent with excellent stability for against CRAB infections.


Asunto(s)
Infecciones por Acinetobacter , Acinetobacter baumannii , Bacteriófagos , Carbapenémicos , Genoma Viral , Terapia de Fagos , Filogenia , Aguas del Alcantarillado , Acinetobacter baumannii/virología , Acinetobacter baumannii/efectos de los fármacos , Aguas del Alcantarillado/virología , Aguas del Alcantarillado/microbiología , Animales , Carbapenémicos/farmacología , Bacteriófagos/genética , Bacteriófagos/fisiología , Bacteriófagos/clasificación , Bacteriófagos/aislamiento & purificación , Infecciones por Acinetobacter/microbiología , Ratones , Antibacterianos/farmacología , Sistemas de Lectura Abierta , Modelos Animales de Enfermedad , Mariposas Nocturnas/virología , Mariposas Nocturnas/microbiología , Composición de Base
13.
Chemistry ; 19(24): 7847-55, 2013 Jun 10.
Artículo en Inglés | MEDLINE | ID: mdl-23595913

RESUMEN

n-Heptyl α-D-mannoside (HM) has previously been identified as a nanomolar FimH antagonist able to prevent Escherichia coli adhesion. We have designed mono- and heptavalent glycoconjugates in which HM is tethered to ß-cyclodextrin (ß-CD) through short and long spacers. One-pot click or co-clicking procedures were developed to directly obtain the glycoconjugates from unprotected HM and ß-CD precursors. These FimH antagonists were examined biophysically and in vivo. Reverse titrations by isothermal calorimetry led to trapping of the short-tethered heptavalent ß-CD in a complex with three FimH lectins. Combined dynamic light scattering and small-angle X-ray solution scattering data allowed the construction of a model of the FimH trimer. The heptavalent ß-CDs were shown to capture and aggregate living bacteria in solution and are therefore also able to aggregate FimH when attached to different bacteria pili. The first in vivo evaluation of multivalent FimH inhibitors has been performed. The heptavalent ß-CDs proved to be much more effective anti-adhesive agents than monovalent references with doses of around 2 µg instilled in the mouse bladder leading to a significantly decreased E. coli load. Intravenously injected radiolabeled glycoconjugates can rapidly reach the mouse bladder and >2 µg concentrations can easily be retained over 24 h to prevent fluxing bacteria from rebinding.


Asunto(s)
Antibacterianos/farmacología , Escherichia coli/efectos de los fármacos , Proteínas Fimbrias/antagonistas & inhibidores , Manósidos/farmacología , beta-Ciclodextrinas/farmacología , Adhesinas de Escherichia coli , Animales , Calorimetría , Química Clic , Escherichia coli/química , Fimbrias Bacterianas/efectos de los fármacos , Manósidos/química , Ratones , Modelos Biológicos , beta-Ciclodextrinas/química
14.
Front Microbiol ; 14: 1277178, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37840750

RESUMEN

Antimicrobial resistance is an increasing threat to human populations. The emergence of multidrug-resistant "superbugs" in mycobacterial infections has further complicated the processes of curing patients, thereby resulting in high morbidity and mortality. Early diagnosis and alternative treatment are important for improving the success and cure rates associated with mycobacterial infections and the use of mycobacteriophages is a potentially good option. Since each bacteriophage has its own host range, mycobacteriophages have the capacity to detect specific mycobacterial isolates. The bacteriolysis properties of mycobacteriophages make them more attractive when it comes to treating infectious diseases. In fact, they have been clinically applied in Eastern Europe for several decades. Therefore, mycobacteriophages can also treat mycobacteria infections. This review explores the potential clinical applications of mycobacteriophages, including phage-based diagnosis and phage therapy in mycobacterial infections. Furthermore, this review summarizes the current difficulties in phage therapy, providing insights into new treatment strategies against drug-resistant mycobacteria.

15.
Vaccines (Basel) ; 12(1)2023 Dec 29.
Artículo en Inglés | MEDLINE | ID: mdl-38250851

RESUMEN

Tuberculosis (TB) remains a global infectious disease primarily transmitted via respiratory tract infection. Presently, vaccination stands as the primary method for TB prevention, predominantly reliant on the Bacillus Calmette-Guérin (BCG) vaccine. Although it is effective in preventing disseminated diseases in children, its impact on adults is limited. To broaden vaccine protection, efforts are underway to accelerate the development of new TB vaccines. However, challenges arise due to the limited immunogenicity and safety of these vaccines, necessitating adjuvants to bolster their ability to elicit a robust immune response for improved and safer immunization. These adjuvants function by augmenting cellular and humoral immunity against M. tuberculosis antigens via different delivery systems, ultimately enhancing vaccine efficacy. Therefore, this paper reviews and summarizes the current research progress on M. tuberculosis vaccines and their associated adjuvants, aiming to provide a valuable reference for the development of novel TB vaccines and the screening of adjuvants.

16.
Microbiology (Reading) ; 158(Pt 3): 736-745, 2012 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-22174382

RESUMEN

NAD and NADP are ubiquitous in the metabolism of Escherichia coli K-12. NAD auxotrophy can be rendered by mutation in any of the three genes nadB, nadA and nadC. The nadB and nadA genes were defined as antivirulence loci in Shigella spp., as a mutation (mainly in nadB) disrupting the synthesis of quinolinate is required for virulence. Uropathogenic E. coli (UPEC) isolates from acute cystitis patients, exhibiting nicotinamide auxotrophy, were of serotype O18 : K1 : H7. E. coli UTI89, the model uropathogenic and O18 : K1 : H7 strain, requires nicotinamide or quinolinate for growth. A mutation in the nadB gene, encoding L-aspartate oxidase, was shown to be responsible for the nicotinamide requirement of UTI89. This was further confirmed by complementation of UTI89 with a recombinant plasmid harbouring the nadB gene of E. coli K-12. An Ala28Val point mutant of the recombinant plasmid failed to support the growth of UTI89 in minimal medium. This proves that the Ala28Val mutation in the NadB gene of UTI89 completely impedes de novo synthesis of nicotinamide. In spontaneous prototrophic revertants of UTI89, the nadB gene has a Val28Ala mutation. Both analyses implicate that the nicotinamide auxotrophy of UTI89 is caused by a single Ala28Val mutation in NadB. We showed that the same mutation is also present in other NAD auxotrophic E. coli O18 strains. No significant differences were observed between the virulence of isogenic NAD auxotrophic and prototrophic strains in the murine ascending urinary tract infection model. Considering these data, we applied the nadB locus as a neutral site for DNA insertions in the bacterial chromosome. We successfully restored the parental phenotype of a fimH mutant by inserting fimH, with a synthetic em7 promoter, into the nadB gene. This neutral insertion site is of significance for further research on the pathogenicity of UPEC.


Asunto(s)
Mutagénesis Insercional , Niacinamida/metabolismo , Escherichia coli Uropatógena/genética , Escherichia coli Uropatógena/metabolismo , Sustitución de Aminoácidos/genética , Animales , ADN Bacteriano/química , ADN Bacteriano/genética , Modelos Animales de Enfermedad , Femenino , Prueba de Complementación Genética , Humanos , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C3H , Ratones Endogámicos CBA , Datos de Secuencia Molecular , Proteínas Mutantes/genética , Proteínas Mutantes/metabolismo , Mutación Puntual , Ácido Quinolínico/metabolismo , Análisis de Secuencia de ADN , Infecciones Urinarias/microbiología , Escherichia coli Uropatógena/aislamiento & purificación
17.
Proc Natl Acad Sci U S A ; 106(52): 22439-44, 2009 Dec 29.
Artículo en Inglés | MEDLINE | ID: mdl-20018753

RESUMEN

FimH, the type 1 pilus adhesin of uropathogenic Escherichia coli (UPEC), contains a receptor-binding domain with an acidic binding pocket specific for mannose. The fim operon, and thus type 1 pilus production, is under transcriptional control via phase variation of an invertible promoter element. FimH is critical during urinary tract infection for mediating colonization and invasion of the bladder epithelium and establishment of intracellular bacterial communities (IBCs). In silico analysis of FimH gene sequences from 279 E. coli strains identified specific amino acids evolving under positive selection outside of its mannose-binding pocket. Mutating two of these residues (A27V/V163A) had no effect on phase variation, pilus assembly, or mannose binding in vitro. However, compared to wild-type, this double mutant strain exhibited a 10,000-fold reduction in mouse bladder colonization 24 h after inoculation and was unable to form IBCs even though it bound normally to mannosylated receptors in the urothelium. In contrast, the single A62S mutation altered phase variation, reducing the proportion of piliated cells, reduced mannose binding 8-fold, and decreased bladder colonization 30-fold in vivo compared to wild-type. A phase-locked ON A62S mutant restored virulence to wild-type levels even though in vitro mannose binding remained impaired. Thus, positive selection analysis of FimH has separated mannose binding from in vivo fitness, suggesting that IBC formation is critical for successful infection of the mammalian bladder, providing support for more general use of in silico positive selection analysis to define the molecular underpinnings of bacterial pathogenesis.


Asunto(s)
Adhesinas de Escherichia coli/genética , Adhesinas de Escherichia coli/fisiología , Infecciones por Escherichia coli/metabolismo , Infecciones por Escherichia coli/microbiología , Proteínas Fimbrias/genética , Proteínas Fimbrias/fisiología , Manosa/metabolismo , Infecciones Urinarias/metabolismo , Infecciones Urinarias/microbiología , Escherichia coli Uropatógena/fisiología , Escherichia coli Uropatógena/patogenicidad , Adhesinas de Escherichia coli/química , Sustitución de Aminoácidos , Animales , Proteínas Fimbrias/química , Genes Bacterianos , Ratones , Ratones Endogámicos C3H , Modelos Moleculares , Datos de Secuencia Molecular , Mutagénesis Sitio-Dirigida , Mutación , Filogenia , Selección Genética , Vejiga Urinaria/microbiología , Escherichia coli Uropatógena/genética , Virulencia/genética , Virulencia/fisiología
18.
Front Mol Biosci ; 9: 1053888, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36589237

RESUMEN

The endogenous plasmid pUTI89 harbored by the uropathogenic Escherichia coli (UPEC) strain UTI89 plays an important role in the acute stage of infection. The partitioning gene parB is important for stable inheritance of pUTI89. However, the function of partitioning genes located on the plasmid in pathogenesis of UPEC still needs to be further investigated. In the present study, we observed that disruption of the parB gene leads to a deficiency in biofilm formation in vitro. Moreover, in a mixed infection with the wild type strain and the parB mutant, in an ascending UTI mouse model, the mutant displayed a lower bacterial burden in the bladder and kidneys, not only at the acute infection stage but also extending to 72 hours post infection. However, in the single infection test, the reduced colonization ability of the parB mutant was only observed at six hpi in the bladder, but not in the kidneys. The colonization capacity in vivo of the parB-complemented strain was recovered. qRT-PCR assay suggested that ParB could be a global regulator, influencing the expression of genes located on both the endogenous plasmid and chromosome, while the gene parA or the operon parAB could not. Our study demonstrates that parB contributes to the virulence of UPEC by influencing biofilm formation and proposes that the parB gene of the endogenous plasmid could regulate gene expression globally.

19.
ACS Appl Mater Interfaces ; 14(38): 43010-43025, 2022 Sep 28.
Artículo en Inglés | MEDLINE | ID: mdl-36108772

RESUMEN

Preventing bacterial infections and accelerating wound closure are essential in the process of wound healing. Current wound dressings lack enough mechanical properties, self-healing ability, and tissue adhesiveness, and the bacterial killing also relies on the use of antibiotic drugs. Herein, a well-designed hybrid hydrogel dressing is constructed by simple copolymerization of acrylamide (AM), 3-acrylamido phenylboronic acid (AAPBA), chitosan (CS), and the nanoscale tannic acid (TA)/ferric ion (Fe3+) complex (TFe). The resulting hydrogel possesses lots of free catechol, phenylboronic acid, amine, and hydroxyl groups and contains many reversible and dynamic bonds such as multiple hydrogen bonds and boronate ester bonds, thereby showing satisfactory mechanical properties, fast self-healing ability, and desirable tissue-adhesive performance. Benefiting from the high photothermal conversion efficiency of the TFe, the hydrogel exhibits satisfactory antibacterial activity against both Gram-positive and Gram-negative bacteria. Moreover, the embedded TFe also endows the hydrogel with good antioxidant activity, anti-inflammatory property, and cell proliferation to promote tissue regeneration. Remarkably, in vivo animal assays reveal that the hybrid hydrogel effectively eliminates biofilm bacteria in the wound sites and accelerates the healing process of infected wounds. Taken together, the developed versatile hydrogels overcome the shortcomings of traditional wound dressings and are expected to become potential antibacterial dressings for future biomedical applications.


Asunto(s)
Infecciones Bacterianas , Quitosano , Adhesivos Tisulares , Infección de Heridas , Animales , Acrilamidas/farmacología , Aminas/farmacología , Antibacterianos/química , Antibacterianos/farmacología , Antioxidantes/química , Infecciones Bacterianas/tratamiento farmacológico , Infecciones Bacterianas/prevención & control , Vendajes , Ácidos Borónicos , Catecoles/farmacología , Quitosano/química , Quitosano/farmacología , Ésteres/farmacología , Bacterias Gramnegativas , Bacterias Grampositivas , Hidrogeles/química , Hidrogeles/farmacología , Taninos/farmacología , Adhesivos Tisulares/química , Cicatrización de Heridas , Infección de Heridas/tratamiento farmacológico
20.
ACS Appl Bio Mater ; 2022 Aug 22.
Artículo en Inglés | MEDLINE | ID: mdl-35994754

RESUMEN

Pathogenic bacterial infections of skin wounds have caused a significant threat to clinical treatment and human life safety. Here, we develop a bactericidal hydrogel dressing consisting of a polyacrylamide (PAM) hydrogel framework with in situ surface-deposition of iron-dopped polydopamine (FePDA). The prepared hydrogel dressing (FePDA-PAM) has a compact surface, good tensile strength, and excellent elastic recovery ability. The introduction of Fe3+ ions improve the photothermal therapy (PTT) efficiency of the PDA and endow the hydrogel dressing with chemodynamic therapy (CDT) properties. In vitro experiments show that the antibacterial effect of FePDA-PAM hydrogel on Staphylococcus aureus reach nearly 100% under the combined action of H2O2 and 808 nm near-infrared (NIR) laser, indicating an excellent combined antibacterial property of PTT and CDT. Furthermore, the FePDA-PAM + H2O2 + NIR treatment group in the in vivo antibacterial experiments displays lowest relative wound area and optimal wound healing within 5 days of treatment, thereby indicating the intensive skin wound disinfection. To summarize, the FePDA-PAM hydrogel has simple preparation and good biosafety. It may serve as a potential wound dressing for the combined PTT/CDT dual-mode antibacterial therapy.

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