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1.
Nucleic Acids Res ; 52(7): 3856-3869, 2024 Apr 24.
Artículo en Inglés | MEDLINE | ID: mdl-38477346

RESUMEN

The genetic diversities of subpopulations drive the evolution of pathogens and affect their ability to infect hosts and cause diseases. However, most studies to date have focused on the identification and characterization of adaptive mutations in single colonies, which do not accurately reflect the phenotypes of an entire population. Here, to identify the composition of variant subpopulations within a pathogen population, we developed a streamlined approach that combines high-throughput sequencing of the entire population cells with genotyping of single colonies. Using this method, we reconstructed a detailed quorum-sensing (QS) evolutionary trajectory in Pseudomonas aeruginosa. Our results revealed a new adaptive mutation in the gacS gene, which codes for a histidine kinase sensor of a two-component system (TCS), during QS evolution. This mutation reduced QS activity, allowing the variant to sweep throughout the whole population, while still being vulnerable to invasion by the emerging QS master regulator LasR-null mutants. By tracking the evolutionary trajectory, we found that mutations in gacS facilitated QS-rewiring in the LasR-null mutant. This rapid QS revertant caused by inactive GacS was found to be associated with the promotion of ribosome biogenesis and accompanied by a trade-off of reduced bacterial virulence on host cells. In conclusion, our findings highlight the crucial role of the global regulator GacS in modulating the progression of QS evolution and the virulence of the pathogen population.


Asunto(s)
Proteínas Bacterianas , Evolución Molecular , Mutación , Pseudomonas aeruginosa , Percepción de Quorum , Pseudomonas aeruginosa/genética , Pseudomonas aeruginosa/patogenicidad , Percepción de Quorum/genética , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Virulencia/genética , Transactivadores/genética , Transactivadores/metabolismo , Secuenciación de Nucleótidos de Alto Rendimiento , Humanos , Regulación Bacteriana de la Expresión Génica , Histidina Quinasa/genética , Histidina Quinasa/metabolismo
2.
PLoS Pathog ; 20(3): e1012078, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38484003

RESUMEN

XRE-cupin family proteins containing an DNA-binding domain and a cupin signal-sensing domain are widely distributed in bacteria. In Pseudomonas aeruginosa, XRE-cupin transcription factors have long been recognized as regulators exclusively controlling cellular metabolism pathways. However, their potential functional roles beyond metabolism regulation remain unknown. PsdR, a typical XRE-cupin transcriptional regulator, was previously characterized as a local repressor involved solely in dipeptide metabolism. Here, by measuring quorum-sensing (QS) activities and QS-controlled metabolites, we uncover that PsdR is a new QS regulator in P. aeruginosa. Our RNA-seq analysis showed that rather than a local regulator, PsdR controls a large regulon, including genes associated with both the QS circuit and non-QS pathways. To unveil the underlying mechanism of PsdR in modulating QS, we developed a comparative transcriptome approach named "transcriptome profile similarity analysis" (TPSA). Using this TPSA method, we revealed that PsdR expression causes a QS-null-like transcriptome profile, resulting in QS-inactive phenotypes. Based on the results of TPSA, we further demonstrate that PsdR directly binds to the promoter for the gene encoding the QS master transcription factor LasR, thereby negatively regulating its expression and influencing QS activation. Moreover, our results showed that PsdR functions as a negative virulence regulator, as inactivation of PsdR enhanced bacterial cytotoxicity on host cells. In conclusion, we report on a new QS regulation role for PsdR, providing insights into its role in manipulating QS-controlled virulence. Most importantly, our findings open the door for a further discovery of untapped functions for other XRE-Cupin family proteins.


Asunto(s)
Proteínas Bacterianas , Pseudomonas aeruginosa , Pseudomonas aeruginosa/metabolismo , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Percepción de Quorum/fisiología , Factores de Transcripción/genética , Factores de Transcripción/metabolismo , Virulencia , Regulación Bacteriana de la Expresión Génica , Factores de Virulencia/metabolismo
3.
Chemistry ; 30(17): e202303996, 2024 Mar 20.
Artículo en Inglés | MEDLINE | ID: mdl-38165074

RESUMEN

Inorganic-organic hybrid materials are a kind of multiduty materials with high crystallinity and definite structures, built from functional inorganic and organic components with highly tunable photochemical properties. Perylenediimides (PDIs) are a kind of strong visible light-absorbing organic dyes with π-electron-deficient planes and photochemical properties depending on their micro-environment, which provides a platform for designing tunable and efficient hybrid photocatalytic materials. Herein, four radical-doped PDI-based crystalline hybrid materials, Cl4-PDI⋅SiW12O40 (1), Cl4-PDI⋅SiMo12O40 (2), Cl4-PDI⋅PW12O40 (3), and Cl4-PDI⋅PMo12O40 (4), were attained by slow diffusion of polyoxometalates (POMs) into acidified Cl4-PDI solutions. The obtained PDI-based crystalline hybrid materials not only exhibited prominent photochromism, but also possessed reactive organic radicals under ambient conditions. Furthermore, all hybrid materials could be easily photoreduced to their radical anions (Cl4-PDI⋅-), and then underwent a second photoexcitation to form energetic excited state radical anions (Cl4-PDI⋅-*). However, experiments and theoretical calculations demonstrated that the formed energetic Cl4-PDI⋅-* showed unusual POM-dependent photocatalytic efficiencies toward the oxidative coupling of amines and the iodoperfluoroalkylation of alkenes; higher photocatalytic efficiencies were found for hybrid materials 1 (anion: SiW12O40 4-) and 2 (anion: SiMo12O40 4-) compared to 3 (anion: PW12O40 3-) and 4 (anion: PMo12O40 3-). The photocatalytic efficiencies of these hybrid materials are mainly controlled by the energy differences between the SOMO-2 level of Cl4-PDI⋅-* and the LUMO level of the POMs. The structure-photocatalytic activity relationships established in present work provide new research directions to both the photocatalysis and hybrid material fields, and will promote the integration of these areas to explore new materials with interesting properties.

4.
Dalton Trans ; 52(45): 16993-17004, 2023 Nov 21.
Artículo en Inglés | MEDLINE | ID: mdl-37933477

RESUMEN

Nitrogen complexation with π-conjugated ligands is an effective strategy for synthesizing luminescent molecules. The asymmetric bridging ligands L (L1 and L2) have been designed. The terminal chelating sites of the L1 and L2 bridging ligands consisted of 2,2'-bipyridine (bpy) and 1,10-phenanthroline moieties (where L = L1 and L2; L1 = 2-(3-((4-([2,2'-bipyridin]-6-yl)benzyl)oxy)phenyl)-1H-imidazo[4,5-f][1,10]phenanthroline and L2 = 2-(3-((4-(6-phenyl-[2,2'-bipyridin]-4-yl)benzyl)oxy)phenyl)-1H-imidazo[4,5-f][1,10]phenanthroline). The full use of the synthetic strategy of the "complexes as ligands and complexes as metals" was expected to successfully design and synthesize a series of conjugated metal-exchange complexes linked by the asymmetric bridging ligands L1 and L2. These compounds included monometallic complexes Ru(L) and (L)Ru (C1, C2, C7, and C8), homometallic complexes Ru(L)Ru (C3 and C4), and heterometallic complexes Os(L)Ru and Ru(L)Os (C5, C6, C9, and C10) with Ru- or Os-based units. C3-C10 complexes exhibited various degrees of octahedral distortion around the Ru(II) or Os(II) center, which was consistent with the optimized geometry of the coordination complexes based on density functional theory calculation. These complexes exhibited intense spin-allowed ligand-centered transitions with high absorbance at around 288 nm upon absorbing visible light. Notably, all complexes exhibited spin-allowed metal-to-ligand charge transfer absorption of the Ru-based units in the 440-450 nm range. In addition, the heterometallic C5, C6, C9, and C10 complexes showed absorption of the Os-based units in the range of 565-583 nm. The intramolecular energy transfer of C3 and C5 was briefly discussed by comparing the emission intensity of monometallic C1 and C2 to that of binuclear complexes C3 and C5, respectively. The results indicated that the intramolecular energy transfer of the Ru(II)/Os(II) polypyridine complexes proceeded from the Ru(II)- to the Os(II)-based units in the heterometallic C5 and C6 complexes.

5.
Mol Biol Evol ; 40(10)2023 10 04.
Artículo en Inglés | MEDLINE | ID: mdl-37708386

RESUMEN

Quorum-sensing (QS) coordinates the expression of virulence factors in Pseudomonas aeruginosa, an opportunistic pathogen known for causing severe infections in immunocompromised patients. QS has a master regulator, the lasR gene, but in clinical settings, P. aeruginosa isolates have been found that are QS-active but LasR-null. In this study, we developed an experimental evolutionary approach to identify additional QS-reprogramming determinants. We began the study with a LasR-null mutant with an extra copy of mexT, a transcriptional regulator gene that is known to be able to reprogram QS in laboratory LasR-null strains. In this strain, spontaneous single mexT mutations are expected to have no or little phenotypic consequences. Using this novel method, which we have named "targeted gene duplication followed by mutant screening", we identified QS-active revertants with mutations in genes other than mexT. One QS-active revertant had a point mutation in rpoA, a gene encoding the α-subunit of RNA polymerase. QS activation in this mutant was found to be associated with the downregulated expression of mexEF-oprN efflux pump genes. Our study therefore uncovers a new functional role for RpoA in regulating QS activity. Our results indicate that a RpoA-dependent regulatory circuit controlling the expression of the mexEF-oprN operon is critical for QS-reprogramming. In conclusion, our study reports on the identification of non-MexT proteins associated with QS-reprogramming in a laboratory strain, shedding light on possible QS activation mechanisms in clinical P. aeruginosa isolates.


Asunto(s)
Pseudomonas aeruginosa , Percepción de Quorum , Humanos , Percepción de Quorum/genética , Pseudomonas aeruginosa/genética , Mutación , Factores de Virulencia/genética , Factores de Virulencia/metabolismo , Evolución Biológica , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Regulación Bacteriana de la Expresión Génica
6.
J Antimicrob Chemother ; 78(9): 2162-2169, 2023 09 05.
Artículo en Inglés | MEDLINE | ID: mdl-37428003

RESUMEN

BACKGROUND: RNA polymerase (RNAP) is highly conserved and essential for prokaryotic housekeeping activities, making it an important target for the development of new antibiotics. The rpoB gene, encoding a ß-subunit of bacterial RNAP, has a well-known association with rifampicin resistance. However, the roles of other RNAP component genes such as rpoA, encoding an α-subunit of RNAP, in antibiotic resistance remain unexplored. OBJECTIVES: To characterize the antibiotic resistance-related role of RpoA. METHODS: We measured the expression of the MexEF-OprN efflux pump in an RpoA mutant using a transcriptional reporter. The MICs of various antibiotics for this RpoA mutant were determined. RESULTS: We uncover a novel role of antibiotic susceptibility for an RpoA mutant in Pseudomonas aeruginosa. We found that a single amino acid substitution in RpoA resulted in reduced activity of the MexEF-OprN efflux pump, which is responsible for the exportation of various antibiotics, including ciprofloxacin, chloramphenicol, ofloxacin and norfloxacin. This attenuated efflux pump activity, caused by the RpoA mutation, conferred the bacteria further susceptibility to antibiotics regulated by MexEF-OprN. Our work further revealed that certain clinical P. aeruginosa isolates also contained the same RpoA mutation, providing clinical relevance to our findings. Our results elucidate why this new antibiotic-susceptible function of RpoA mutants would have remained undetected in conventional screens for mutants involving antibiotic resistance. CONCLUSIONS: The discovery of antibiotic susceptibility in an RpoA mutant implicates a new therapeutic approach for treating clinical isolates of P. aeruginosa with RpoA mutations, using specific antibiotics regulated by MexEF-OprN. More generally, our work suggests that RpoA could serve as a promising candidate target for anti-pathogen therapeutic purposes.


Asunto(s)
Antibacterianos , Pseudomonas aeruginosa , Antibacterianos/farmacología , Antibacterianos/metabolismo , Ciprofloxacina/farmacología , Cloranfenicol/metabolismo , ARN Polimerasas Dirigidas por ADN/genética , Proteínas de la Membrana Bacteriana Externa/genética
7.
Dalton Trans ; 52(4): 990-999, 2023 Jan 24.
Artículo en Inglés | MEDLINE | ID: mdl-36601979

RESUMEN

Novel monometallic (µ-LL')Ru, Ru(µ-LL'), homobimetallic Ru(µ-LL')Ru, and heterodimetallic Ru(µ-LL')Os and Os(µ-LL')Ru complexes based on two asymmetrical ligands LL' (where LL' = L1L1', L2L2') have been synthesized and characterized. Spectroscopic analysis indicates that all complexes exhibit intense spin-allowed ligand-centered (LC) transitions at 288 nm and Ru-based moderate spin-allowed MLCT absorption between 440-450 nm. The Ru(µ-LL')Os and Os(µ-LL')Ru dinuclear complexes show Os-based unit absorption in the range of 565-583 nm. The Ru-based units of the complexes present different emission intensities due to differing steric hindrance at the coordination sites of the two bridging ligands. The Os(µ-LL')Ru dinuclear complexes present weaker emission intensity than their parent monometallic complexes (µ-LL')Ru. These results indicate that the emission of Os(µ-LL')Ru dinuclear complexes is quenched by the Os(II)-based units.


Asunto(s)
Rutenio , Estructura Molecular , Ligandos , Rutenio/química , Espectroscopía de Resonancia Magnética , Transferencia de Energía
8.
J Microbiol Methods ; 204: 106654, 2023 01.
Artículo en Inglés | MEDLINE | ID: mdl-36509134

RESUMEN

We develop a biotin-based tandem labeling approach to improve detection sensitivity of DNA probe. Through DNA polymerase-mediated overhand filling, the 3'end of DNA probe was tandemly labeled with biotin molecules. The intensity of biotin signals could be flexibly manipulated by controlling the introduced length of poly(A) in the 5' overhang.


Asunto(s)
Biotina , Biotinilación , Sondas de ADN
9.
AMB Express ; 12(1): 6, 2022 Jan 26.
Artículo en Inglés | MEDLINE | ID: mdl-35083573

RESUMEN

Pseudomonas aeruginosa strain PAO1 has been commonly used in the laboratory, with frequent genome variations reported. Quorum sensing (QS), a cell-cell communication system, plays important role in controlling a variety of virulence factors. However, the evolution and adaptability of QS in those laboratory strains are still poorly understood. Here we used the QS reporter and whole-genome sequencing (WGS) to systematically investigate the QS phenotypes and corresponding genetic basis in collected laboratory PAO1 strains. We found that the PAO1-z strain has an inactive LasR protein, while bearing an active Rhl QS system and exhibiting QS-controlled protease-positive activity. Our study revealed that an 18-bp insertion in mexT gene gave rise to the active QS system in the PAO1-z strain. This MexT inactivation restored the QS activity caused by the inactive LasR, showing elevated production of pyocyanin, cyanide and elastase. Our results implied the evolutionary trajectory for the PAO1-z strain, with the evulutionary order from the first Las QS inactivation to the final Rhl QS activation. Our findings point out that QS homeostasis occurs in the laboratory P. aeruginosa strain, offering a potential platform for the QS study in clinical isolates.

10.
Bosn J Basic Med Sci ; 22(1): 77-86, 2022 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-34255617

RESUMEN

Growing evidence has suggested that abnormally expressed long non-coding RNAs (lncRNAs) play critical regulatory roles in nasopharyngeal carcinoma (NPC) pathogenesis. Family with sequence similarity 225 member B (FAM225B) is a novel lncRNA that has been implicated in several human cancers, yet its role in the context of NPC remains largely unclear. The aim of this study was to determine the expression level of FAM225B and its clinical significance in NPC patients. We observed a remarkable increase of FAM225B in NPC tissues and cell lines compared with controls. Also, highly expressed FAM225B was closely correlated with advanced TNM stage, distant metastasis, and poor overall survival. Interestingly, loss-of-function analysis revealed that FAM225B knockdown significantly inhibited tumor growth in vitro and in vivo, and decreased the migratory and invasive capacity of NPC cells. Mechanically, FAM225B functioned as an endogenous sponge by competing for miR-613 binding to up-regulate CCND2 expression. More importantly, rescue experiments further demonstrated that the suppressive impacts of FAM225B knockdown on cell proliferation, migration and invasion were significantly reversed after CCND2 overexpression. Taken all together, these findings highlight FAM225B as an oncogene that promotes NPC proliferation and metastasis through miR-613/CCND2 axis.


Asunto(s)
MicroARNs , Neoplasias Nasofaríngeas , ARN Largo no Codificante , Línea Celular Tumoral , Proliferación Celular/genética , Ciclina D2/genética , Ciclina D2/metabolismo , Regulación Neoplásica de la Expresión Génica , Humanos , MicroARNs/genética , MicroARNs/metabolismo , Carcinoma Nasofaríngeo/genética , Carcinoma Nasofaríngeo/metabolismo , Carcinoma Nasofaríngeo/patología , Neoplasias Nasofaríngeas/genética , Neoplasias Nasofaríngeas/patología , ARN Largo no Codificante/genética , ARN Largo no Codificante/metabolismo
11.
Appl Microbiol Biotechnol ; 106(1): 341-347, 2022 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-34889987

RESUMEN

Essential genes are crucial for bacterial viability and represent attractive targets for novel anti-pathogen drug discovery. However, essential genes determined by the transposon insertion sequencing (Tn-seq) approach often contain many false positives. We hypothesized that some of those false positives are genes that are actually deleted from the genome, so they do not present any transposon insertion in the course of Tn-seq analysis. Based on this assumption, we performed a large-scale whole-genome sequencing analysis for the bacterium of interest. Our analysis revealed that some "essential genes" are indeed removed from the analyzed bacterial genomes. Since these genes were kicked out by bacteria, they should not be defined as essential. Our work showed that gene deletion is one of the false positive sources of essentiality determination, which is apparently underestimated in previous studies. We suggest subtracting the genome backgrounds before the evaluation of Tn-seq, and created a list of false positive gene essentiality as a reference for the downstream application. KEY POINTS: • Discovery of false positives of essential genes defined previously through the analyses of a large scale of whole-genome sequencing data • These false positives are the results of gene deletions in the studied genomes • Sequencing the target genome before Tn-seq analysis is of importance while some studies neglected it.


Asunto(s)
Elementos Transponibles de ADN , Genes Esenciales , Bacterias , Genes Bacterianos , Genoma Bacteriano , Secuenciación de Nucleótidos de Alto Rendimiento , Mutagénesis Insercional
12.
Microorganisms ; 9(12)2021 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-34946092

RESUMEN

Exopolysaccharides (EPS) play critical roles in rhizobium-plant interactions. However, the EPS biosynthesis pathway in Bradyrhizobium diazoefficiens USDA110 remains elusive. Here we used transposon (Tn) mutagenesis with the aim to identify genetic elements required for EPS biosynthesis in B. diazoefficiens USDA110. Phenotypic screening of Tn5 insertion mutants grown on agar plates led to the identification of a mutant with a transposon insertion site in the blr2358 gene. This gene is predicted to encode a phosphor-glycosyltransferase that transfers a phosphosugar onto a polyprenol phosphate substrate. The disruption of the blr2358 gene resulted in defective EPS synthesis. Accordingly, the blr2358 mutant showed a reduced capacity to induce nodules and stimulate the growth of soybean plants. Glycosyltransferase genes related to blr2358 were found to be well conserved and widely distributed among strains of the Bradyrhizobium genus. In conclusion, our study resulted in identification of a gene involved in EPS biosynthesis and highlights the importance of EPS in the symbiotic interaction between USDA110 and soybeans.

13.
Int J Mol Sci ; 22(18)2021 Sep 13.
Artículo en Inglés | MEDLINE | ID: mdl-34576026

RESUMEN

Quorum sensing (QS) is a microbial cell-cell communication mechanism and plays an important role in bacterial infections. QS-mediated bacterial infections can be blocked through quorum quenching (QQ), which hampers signal accumulation, recognition, and communication. The pathogenicity of numerous bacteria, including Xanthomonas campestris pv. campestris (Xcc), is regulated by diffusible signal factor (DSF), a well-known fatty acid signaling molecule of QS. Cupriavidus pinatubonensis HN-2 could substantially attenuate the infection of XCC through QQ by degrading DSF. The QQ mechanism in strain HN-2, on the other hand, is yet to be known. To understand the molecular mechanism of QQ in strain HN-2, we used whole-genome sequencing and comparative genomics studies. We discovered that the fadT gene encodes acyl-CoA dehydrogenase as a novel QQ enzyme. The results of site-directed mutagenesis demonstrated the requirement of fadT gene for DSF degradation in strain HN-2. Purified FadT exhibited high enzymatic activity and outstanding stability over a broad pH and temperature range with maximal activity at pH 7.0 and 35 °C. No cofactors were required for FadT enzyme activity. The enzyme showed a strong ability to degrade DSF. Furthermore, the expression of fadT in Xcc results in a significant reduction in the pathogenicity in host plants, such as Chinese cabbage, radish, and pakchoi. Taken together, our results identified a novel DSF-degrading enzyme, FadT, in C. pinatubonensis HN-2, which suggests its potential use in the biological control of DSF-mediated pathogens.


Asunto(s)
Acil-CoA Deshidrogenasa/genética , Infecciones Bacterianas/genética , Ácidos Grasos/genética , Enfermedades de las Plantas/genética , Xanthomonas campestris/genética , Acil-CoA Deshidrogenasa/química , Acil-CoA Deshidrogenasa/aislamiento & purificación , Infecciones Bacterianas/microbiología , Brassica/crecimiento & desarrollo , Brassica/microbiología , Comunicación Celular/genética , Ácidos Grasos/metabolismo , Regulación Enzimológica de la Expresión Génica , Genoma Bacteriano/genética , Genómica , Mutagénesis Sitio-Dirigida , Enfermedades de las Plantas/microbiología , Percepción de Quorum/genética , Raphanus/genética , Raphanus/microbiología , Transducción de Señal/genética , Factores de Virulencia/genética , Secuenciación Completa del Genoma , Xanthomonas campestris/enzimología
14.
Sci Rep ; 11(1): 13211, 2021 06 24.
Artículo en Inglés | MEDLINE | ID: mdl-34168197

RESUMEN

Bradyrhizobium diazoefficiens USDA110 is one of the most effective nitrogen-fixing symbionts of soybeans. Here we carried out a large-scale transposon insertion sequencing (Tn-seq) analysis of strain Bd110spc4, which is derived from USDA110, with the goal of increasing available resources for identifying genes crucial for the survival of this plant symbiont under diverse conditions. We prepared two transposon (Tn) insertion libraries of Bd110spc4 with 155,042 unique Tn insertions when the libraries were combined, which is an average of one insertion every 58.7 bp of the reference USDA110 genome. Application of bioinformatic filtering steps to remove genes too small to be expected to have Tn insertions, resulted in a list of genes that were classified as putatively essential. Comparison of this gene set with genes putatively essential for the growth of the closely related alpha-proteobacterium, Rhodopseudomonas palustris, revealed a small set of five genes that may be collectively essential for closely related members of the family Bradyrhizobiaceae. This group includes bacteria with diverse lifestyles ranging from plant symbionts to animal-associated species to free-living species.


Asunto(s)
Bradyrhizobium/genética , Elementos Transponibles de ADN/genética , Proteínas Bacterianas/genética , Fijación del Nitrógeno/genética , Rhodopseudomonas/genética
15.
J Clin Pharmacol ; 61(1): 74-81, 2021 01.
Artículo en Inglés | MEDLINE | ID: mdl-32656769

RESUMEN

The revised Provisions for Drug Registration was promulgated by the State Administration for Market Regulation of China in March 2020 and came into force on July 1, 2020. This article describes the history of the drug registration management system in China, explains the background of the revision of the Provisions for Drug Registration in 2020, and introduces the main modifications of the Provisions for Drug Registration in 2020 in the aspects of registration classification, application for clinical trial on drug, application for drug marketing authorization, accelerated procedure for drug registration, working timeline, and supervision and administration. This article is intended to give a brief overview for those who wish to submit a drug registration application in China or for those who would like to get more acquainted with drug registration in China.


Asunto(s)
Aprobación de Drogas/organización & administración , China , Ensayos Clínicos como Asunto/legislación & jurisprudencia , Aprobación de Drogas/legislación & jurisprudencia , Humanos , Mercadotecnía/legislación & jurisprudencia , Factores de Tiempo
16.
Environ Microbiol Rep ; 12(6): 656-666, 2020 12.
Artículo en Inglés | MEDLINE | ID: mdl-32929871

RESUMEN

Many Gram-negative bacteria communicate by using homoserine lactones (HSLs) as quorum sensing (QS) signals in a cell density-dependent manner. In addition to fatty acyl-HSL (acyl-HSL) signals, certain strains, most of them associated with plants, produce non-canonical aryl-HSLs such as cinnamoyl-HSL. However, the role of aryl-HSL in endophytic associations remained elusive. Bradyrhizobium sp. strain ORS278 possesses a LuxI-LuxR type QS system and produces cinnamoyl-HSL as a QS signal. Here, we report that strain ORS278 promotes growth of domesticated rice (Oryza sativa). QS mutants unable to produce cinnamoyl-HSL exhibited reduced plant-growth promoting activity in comparison to the parent strain ORS278. Likewise, the QS mutants were impaired in their ability to colonize rice roots. These findings suggest that genes controlled by cinnamoyl-HSL play an important role in the association between rice and ORS278. However, biofilm production was not visibly altered in these mutants. In conclusion, our study highlights the importance of aryl-HSLs in endophytic plant-bacteria interactions.


Asunto(s)
Bradyrhizobium/fisiología , Oryza/crecimiento & desarrollo , Raíces de Plantas/microbiología , Percepción de Quorum , 4-Butirolactona/análogos & derivados , 4-Butirolactona/metabolismo , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Bradyrhizobium/genética , Bradyrhizobium/crecimiento & desarrollo , Regulación Bacteriana de la Expresión Génica , Oryza/microbiología , Raíces de Plantas/crecimiento & desarrollo
17.
Mol Carcinog ; 59(11): 1280-1291, 2020 11.
Artículo en Inglés | MEDLINE | ID: mdl-32965071

RESUMEN

Sirtuin 2 (SIRT2) is one of seven mammalian homologs of silent information regulator 2 (Sir2) and an NAD+ -dependent deacetylase; however, its critical role in lymphangiogenesis remains to be explored. We investigate SIRT2 mediated regulation of vascular endothelial growth factor D (VEGFD) expression and lymphangiogenesis by deacetylating endothelial PAS domain protein 1 (EPAS1) in head and neck cancer (HNC) in vitro and in vivo. In this study, we report that SIRT2, rather than other members of the Sir2 family, reduces the expression of VEGFD and lymphangiogenesis in hypoxia-induced HNC cells and transplanted HNC mice models by reducing EPAS1 acetylation at Lys674 and decreasing the transcriptional activity of EPAS1 target genes. The expression of SIRT2 was closely related to the expression of VEGFD, lymphangiogenesis in subcutaneously transplanted mice models, and lymphangiogenesis in patients with HNC. Our results suggest that SIRT2 plays a central role in tumor lymphangiogenesis via deacetylating EPAS1 protein. Reagents targeting the NAD+ -dependent deacetylase activity of SIRT2 would be beneficial for inhibiting tumor lymphangiogenesis and treating other hypoxia-related diseases.


Asunto(s)
Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/metabolismo , Biomarcadores de Tumor/metabolismo , Regulación Neoplásica de la Expresión Génica , Neoplasias de Cabeza y Cuello/patología , Linfangiogénesis , Sirtuina 2/metabolismo , Factor D de Crecimiento Endotelial Vascular/metabolismo , Acetilación , Animales , Apoptosis , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/genética , Biomarcadores de Tumor/genética , Proliferación Celular , Femenino , Neoplasias de Cabeza y Cuello/genética , Neoplasias de Cabeza y Cuello/metabolismo , Humanos , Metástasis Linfática , Ratones , Ratones Desnudos , Invasividad Neoplásica , Sirtuina 2/genética , Células Tumorales Cultivadas , Factor D de Crecimiento Endotelial Vascular/genética , Ensayos Antitumor por Modelo de Xenoinjerto
18.
Microbiol Res ; 223-225: 137-143, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31178047

RESUMEN

Pseudomonas aeruginosa is an opportunistic pathogen with high clinical relevance for hospital infections of patients. Accumulating DNA sequencing results of clinical P. aeruginosa isolates have revealed frequent mutations in lasR gene, which encodes the highest arches component of quorum-sensing system (QS). We analyzed the sequencing data of lasR gene from a large collection of cystic fibrosis (CF) P. aeruginosa isolates. Our systematical analyses revealed that single nucleotide polymorphisms (SNPs) selection in lasR gene were largely constrained by codon-usage frequency. As a whole, SNP-substituted codons encoding unconserved amino acid resulted in unfavored codons with relatively low codon-usage frequency, while those associating with conserved amino acid were not strictly regulated in such way. These SNPs substitutions gives rise to diverse functional LasR isoforms and contributes to the relative growth fitness of recombinant lasR variant strains. Our survey reveals a novel pattern of SNPs selections in lasR gene of CF isolates. Our findings could be served as a powerful resource for understanding adaptive mechanism of clinical isolates under environmental constrains and developing anti-bacteria drugs for CF patients.


Asunto(s)
Proteínas Bacterianas/genética , Codón/genética , Fibrosis Quística/microbiología , Polimorfismo de Nucleótido Simple/genética , Pseudomonas aeruginosa/genética , Transactivadores/genética , Secuencia de Aminoácidos , Regulación Bacteriana de la Expresión Génica , Isoformas de Proteínas , Infecciones por Pseudomonas/microbiología , Pseudomonas aeruginosa/crecimiento & desarrollo , Pseudomonas aeruginosa/patogenicidad , Percepción de Quorum/genética , Alineación de Secuencia , Análisis de Secuencia de ADN
19.
mSystems ; 3(6)2018.
Artículo en Inglés | MEDLINE | ID: mdl-30505942

RESUMEN

The rice blast fungus Magnaporthe oryzae poses a great threat to global food security. During its conidiation (asexual spore formation) and appressorium (infecting structure) formation, autophagy is induced, serving glycogen breakdown or programmed cell death function, both essential for M. oryzae pathogenicity. Recently, we identified an M. oryzae histone acetyltransferase (HAT) Gcn5 as a key regulator in phototropic induction of autophagy and asexual spore formation while serving a cellular function other than autophagy induction during M. oryzae infection. To further understand the regulatory mechanism of Gcn5 on M. oryzae pathogenicity, we set out to identify more Gcn5 substrates by comparative acetylome between the wild-type (WT) and GCN5 overexpression (OX) mutant and between OX mutant and GCN5 deletion (knockout [KO]) mutant. Our results showed that Gcn5 regulates autophagy induction and other important aspects of fungal pathogenicity, including energy metabolism, stress response, cell toxicity and death, likely via both epigenetic regulation (histone acetylation) and posttranslational modification (nonhistone protein acetylation). IMPORTANCE Gcn5 is a histone acetyltransferase that was previously shown to regulate phototropic and starvation-induced autophagy in the rice blast fungus Magnaporthe oryzae, likely via modification on autophagy protein Atg7. In this study, we identified more potential substrates of Gcn5-mediated acetylation by quantitative and comparative acetylome analyses. By epifluorescence microscopy and biochemistry experiments, we verified that Gcn5 may regulate autophagy induction at both the epigenetic and posttranslational levels and regulate autophagic degradation of a critical metabolic enzyme pyruvate kinase (Pk) likely via acetylation. Overall, our findings reveal comprehensive posttranslational modification executed by Gcn5, in response to various external stimuli, to synergistically promote cellular differentiation in a fungal pathogen.

20.
Am J Transl Res ; 10(10): 3099-3110, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-30416653

RESUMEN

Background: Postoperative pain has well defined and is perceived by patients as one of the most obnoxious aspects of surgical pain. The aim of this study was to determine whether the combination of Therapeutic ultrasound (TUS) and Curcumin (CUR) resulted in an enhancement of their pain relieving activities in a rat model of postoperative pain. Methods: We explored the effect of these treatment and their interaction with signal transduction pathways involved in inflammatory. In this study, TUS and CUR alone or in combination were administered prior to or simultaneously with or after the incisional surgery. Results: At the start time of administration, we observed that the TUS plus CUR treatment reduced the mean paw withdrawal threshold more efficiently than CUR alone. Then we demonstrated that TUS potentiates the antinociceptive effect of CUR in a rat model of chronic postoperative pain and that the combination could facilitate the recovery of surgical pain. However, preventive value was not statistically significant when the treatments were given prior to the incisional surgery. We provide evidence that TUS plus CUR administrations were safe and significantly reduced the ED50 compared to treatment with the single CUR treatment in rats. TUS plus CUR administrations decreases incisional surgery induced activation of inflammatory cells and down-regulation of chemokines and proinflammatory cytokines, MCP-1, MIP-1α, IL-1ß, and TNF-α through regulating Sirt1/NF-κB signaling pathway. Conclusions: Taken together, our results indicate that the combinations of TUS and CUR can be more effective in the anti-nociceptive effects than the treatment with CUR alone.

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