RESUMEN

Essential amino acid, tryptophan which intake from food plays a critical role in numerous metabolic functions, exhibiting extensive biological functions and applications. Tryptophan is beneficial for the food sector by enhancing nutritional content and promoting the development of functional foods. A putative gene encoding tryptophan synthase was the first identified in Sphingobacterium soilsilvae Em02, a cellulosic bacterium making it inherently more environmentally friendly. The gene was cloned and expressed in exogenous host Escherichia coli, to elucidate its function. The recombinant tryptophan synthase with a molecular weight 42 KDa was expressed in soluble component. The enzymatic activity to tryptophan synthase in vivo was assessed using indole and L-serine and purified tryptophan synthase. The optimum enzymatic activity for tryptophan synthase was recorded at 50 ºC and pH 7.0, which was improved in the presence of metal ions Mg2+, Sr2+ and Mn2+, whereas Cu2+, Zn2+ and Co2+ proved to be inhibitory. Using site-directed mutagenesis, the consensus pattern HK-S-[GGGSN]-E-S in the tryptophan synthase was demonstrated with K100Q, S202A, G246A, E361A and S385A as the active sites. Tryptophan synthase has been demonstrated to possess the defining characteristics of the ß-subunits. The tryptophan synthase may eventually be useful for tryptophan production on a larger scale. Its diverse applications highlight the potential for improving both the quality and health benefits of food products, making it an essential component in advancing food science and technology.

Asunto(s)

Escherichia coli , Mutagénesis Sitio-Dirigida , Triptófano Sintasa , Triptófano , Triptófano Sintasa/metabolismo , Triptófano Sintasa/genética , Triptófano Sintasa/química , Triptófano/metabolismo , Escherichia coli/genética , Escherichia coli/metabolismo , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Proteínas Bacterianas/química , Sphingomonadaceae/enzimología , Sphingomonadaceae/genética , Sphingomonadaceae/metabolismo , Proteínas Recombinantes/metabolismo , Proteínas Recombinantes/genética , Proteínas Recombinantes/química , Dominio Catalítico , Clonación Molecular , Concentración de Iones de Hidrógeno , Indoles/metabolismo , Catálisis , Serina/metabolismo

RESUMEN

BACKGROUND: More than a century has passed since it was discovered that many bacteria produce indole, but research into the actual biological roles of this molecule is just now beginning. The influence of indole on bacterial virulence was extensively investigated in indole-producing bacteria like Escherichia coli. To gain a deeper comprehension of its functional role, this study investigated how indole at concentrations of 0.5-1.0 mM found in the supernatant of Escherichia coli stationary phase culture was able to alter the virulence of non-indole-producing bacteria, such as Pseudomonas aeruginosa, Proteus mirabilis, and Klebsiella pneumoniae, which are naturally exposed to indole in mixed infections with Escherichia coli. RESULTS: Biofilm formation, antimicrobial susceptibility, and efflux pump activity were the three phenotypic tests that were assessed. Indole was found to influence antibiotic susceptibly of Pseudomonas aeruginosa, Proteus mirabilis and Klebsiella pneumoniae to ciprofloxacin, imipenem, ceftriaxone, ceftazidime, and amikacin through significant reduction in MIC with fold change ranged from 4 to 16. Biofilm production was partially abrogated in both 32/45 Pseudomonas aeruginosa and all eight Proteus mirabilis, while induced biofilm production was observed in 30/40 Klebsiella pneumoniae. Moreover, acrAB and oqxAB, which encode four genes responsible for resistance-nodulation-division multidrug efflux pumps in five isolates of Klebsiella pneumoniae were investigated genotypically using quantitative real-time (qRT)-PCR. This revealed that all four genes exhibited reduced expression indicated by 2^-ΔΔCT < 1 in indole-treated isolates compared to control group. CONCLUSION: The outcomes of qRT-PCR investigation of efflux pump expression have established a novel clear correlation of the molecular mechanism that lies beneath the influence of indole on bacterial antibiotic tolerance. This research provides novel perspectives on the various mechanisms and diverse biological functions of indole signaling and how it impacts the pathogenicity of non-indole-producing bacteria.

Asunto(s)

Antibacterianos , Biopelículas , Escherichia coli , Indoles , Klebsiella pneumoniae , Pruebas de Sensibilidad Microbiana , Pseudomonas aeruginosa , Klebsiella pneumoniae/genética , Klebsiella pneumoniae/efectos de los fármacos , Klebsiella pneumoniae/metabolismo , Biopelículas/crecimiento & desarrollo , Biopelículas/efectos de los fármacos , Indoles/metabolismo , Indoles/farmacología , Escherichia coli/genética , Escherichia coli/efectos de los fármacos , Escherichia coli/metabolismo , Antibacterianos/farmacología , Pseudomonas aeruginosa/genética , Pseudomonas aeruginosa/efectos de los fármacos , Pseudomonas aeruginosa/metabolismo , Regulación Bacteriana de la Expresión Génica/efectos de los fármacos , Regulación hacia Abajo , Proteus mirabilis/genética , Proteus mirabilis/efectos de los fármacos , Proteus mirabilis/metabolismo , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Proteínas de Transporte de Membrana/genética , Proteínas de Transporte de Membrana/metabolismo , Virulencia/genética , Proteínas de Escherichia coli/genética , Proteínas de Escherichia coli/metabolismo

RESUMEN

BACKGROUND: Xanthenes and multi-aryl carbon core containing compounds represent different types of complex and condensed architectures that have impressive wide range of pharmacological, industrial and synthetic applications. Moreover, indoles as building blocks were only found in naturally occurring metabolites with di-aryl carbon cores and in chemically synthesized tri-aryl carbon core containing compounds. Up to date, rare xanthenes with indole bearing multicaryl carbon core have been reported in natural or synthetic products. The underlying mechanism of fluorescein-like arthrocolins with tetra-arylmethyl core were synthesized in an engineered Escherichia coli fed with toluquinol remained unclear. RESULTS: In this study, the Keio collection of single gene knockout strains of 3901 mutants of E. coli BW25113, together with 14 distinct E. coli strains, was applied to explore the origins of endogenous building blocks and the biogenesis for arthrocolin assemblage. Deficiency in bacterial respiratory and aromatic compound degradation genes ubiX, cydB, sucA and ssuE inhibited the mutant growth fed with toluquinol. Metabolomics of the cultures of 3897 mutants revealed that only disruption of tnaA involving in transforming tryptophan to indole, resulted in absence of arthrocolins. Further media optimization, thermal cell killing and cell free analysis indicated that a non-enzyme reaction was involved in the arthrocolin biosynthesis in E. coli. Evaluation of redox potentials and free radicals suggested that an oxygen-mediated free radical reaction was responsible for arthrocolins formation in E. coli. Regulation of oxygen combined with distinct phenol derivatives as inducer, 31 arylmethyl core containing metabolites including 13 new and 8 biological active, were isolated and characterized. Among them, novel arthrocolins with p-hydroxylbenzene ring from tyrosine were achieved through large scale of aerobic fermentation and elucidated x-ray diffraction analysis. Moreover, most of the known compounds in this study were for the first time synthesized in a microbe instead of chemical synthesis. Through feeding the rat with toluquinol after colonizing the intestines of rat with E. coli, arthrocolins also appeared in the rat blood. CONCLUSION: Our findings provide a mechanistic insight into in vivo synthesis of complex and condensed arthrocolins induced by simple phenols and exploits a quinol based method to generate endogenous aromatic building blocks, as well as a methylidene unit, for the bacteria-facilitated synthesis of multiarylmethanes.

Asunto(s)

Escherichia coli , Oxígeno , Fenoles , Escherichia coli/metabolismo , Escherichia coli/efectos de los fármacos , Escherichia coli/genética , Fenoles/metabolismo , Oxígeno/metabolismo , Radicales Libres/metabolismo , Metano/metabolismo , Animales , Ratas , Indoles/metabolismo

RESUMEN

Human tryptophan dioxygenase (TDO) and indoleamine 2,3-dioxygenase (IDO) are two important targets in cancer immunotherapy. Extensive research has led to a large number of potent IDO inhibitors; in addition, 52 structures of IDO in complex with inhibitors with a wide array of chemical scaffolds have been documented. In contrast, progress in the development of TDO inhibitors has been limited. Only four structures of TDO in complex with competitive inhibitors that compete with the substrate L-tryptophan for binding to the active site have been reported to date. Here we systematically evaluated the structures of TDO in complex with competitive inhibitors with three types of pharmacophores, imidazo-isoindole, indole-tetrazole, and indole-benzotriazole. The comparative assessment of the protein-inhibitor interactions sheds new light into the structure-based design of enzyme-selective inhibitors.

Asunto(s)

Inhibidores Enzimáticos , Indolamina-Pirrol 2,3,-Dioxigenasa , Triptófano Oxigenasa , Humanos , Triptófano Oxigenasa/antagonistas & inhibidores , Triptófano Oxigenasa/metabolismo , Triptófano Oxigenasa/química , Inhibidores Enzimáticos/química , Inhibidores Enzimáticos/farmacología , Inhibidores Enzimáticos/metabolismo , Indolamina-Pirrol 2,3,-Dioxigenasa/antagonistas & inhibidores , Indolamina-Pirrol 2,3,-Dioxigenasa/metabolismo , Indolamina-Pirrol 2,3,-Dioxigenasa/química , Relación Estructura-Actividad , Indoles/química , Indoles/farmacología , Indoles/metabolismo , Modelos Moleculares , Tetrazoles/química , Tetrazoles/farmacología , Tetrazoles/metabolismo , Triptófano/química , Triptófano/metabolismo , Imidazoles/química , Imidazoles/farmacología , Imidazoles/metabolismo , Unión Proteica

RESUMEN

Indole and pyridine, which are highly produced refractory compounds in the industrial wastewater, exhibit poor degradation capabilities in natural environments. In this study, we developed an anaerobic digestion system coupled with weak electric mediation (ED), and investigated the promoting effect of weak electricity on indole and pyridine biodegradation. The degradation characteristics were systematically explored, and the results showed that the degradation rate and mineralization of indole and pyridine were significantly enhanced, the production of CH4 was increased 1.4-fold, and the optimal voltages were 1.0 V and 0.8 V in the ED, respectively. Moreover, simultaneous removal of carbon and nitrogen was achieved. Gas chromatography-mass spectrometry analysis verified the transformation products, and possible pathways were proposed. Several byproducts of indole and pyridine were identified, with oxindole and glutaric dialdehyde being the main metabolites, respectively. Additionally, density functional theory (DFT) analysis was performed to investigated the radical indices and stabilities of the molecules to further confirm the degradation pathway. Microbial structure analysis demonstrated that the electrically mediated enhanced metabolism and activity of functional microbes, led to the promotion of indole and pyridine mineralization. Moreover, such species as degrading bacteria (Alicycliphilus, Shinella) and electroactive bacteria (Achromobacter), anaerobic ammonia-oxidizing bacteria (SM1A02), and denitrifying bacteria (Thiobacillus) coexisted. This study demonstrates that weak electric mediation is a promising methodology for enhancing the removal of indole and pyridine from wastewater under anaerobic conditions.

Asunto(s)

Biodegradación Ambiental , Indoles , Piridinas , Eliminación de Residuos Líquidos , Piridinas/metabolismo , Indoles/metabolismo , Anaerobiosis , Eliminación de Residuos Líquidos/métodos , Contaminantes Químicos del Agua/metabolismo , Contaminantes Químicos del Agua/análisis , Aguas Residuales/química

RESUMEN

Cyanobacteria possess special defense mechanisms to protect themselves against ultraviolet (UV) radiation. This study combines experimental and computational methods to identify the role of protective strategies in Nostoc species against UV-C radiation. To achieve this goal, various species of the genus Nostoc from diverse natural habitats in Iran were exposed to artificial UV-C radiation. The results indicated that UV-C treatment significantly reduced the photosynthetic pigments while simultaneously increasing the activity of antioxidant enzymes. Notably, N. sphaericum ISB97 and Nostoc sp. ISB99, the brown Nostoc species isolated from habitats with high solar radiations, exhibited greater resistance compared to the green-colored species. Additionally, an increase in scytonemin content occurred with a high expression of key genes associated with its synthesis (scyF and scyD) during the later stages of UV-C exposure in these species. The molecular docking of scytonemin with lipopolysaccharides of the cyanobacteria that mainly cover the extracellular matrix revealed the top/side positioning of scytonemin on the glycans of these lipopolysaccharides to form a UV-protective shield. These findings pave the way for exploring the molecular effects of scytonemin in forming the UV protection shield in cyanobacteria, an aspect that has been ambiguous until now.

Asunto(s)

Nostoc , Rayos Ultravioleta , Nostoc/metabolismo , Nostoc/efectos de la radiación , Simulación del Acoplamiento Molecular , Fenoles/metabolismo , Indoles/metabolismo , Indoles/química , Fotosíntesis/efectos de la radiación , Lipopolisacáridos/metabolismo

RESUMEN

Characterizing the metabolic profiles of synthetic cannabinoids (SCs), a type of new psychoactive substances, is of particular importance for forensic detection and analysis. Although the metabolism of individual SCs derived from 1-amino-3,3-dimethyl-1-oxobutan-2-yl (ADB-SCs) has been reported, their metabolites also undergo a continuous change and combination of their tail and core regions. Therefore, elucidating the metabolic characteristics and effects of these structures is essential to enhance our understanding. In this study, the human liver microsome was used as the model for studying the in vitro phase I metabolism of 12 ADB-SCs, and the metabolites obtained were analyzed using ultra-high performance liquid chromatography-tandem four-level rod-electrostatic field orbital ion trap mass spectrometry to determine type, structure, and relative contents. The results indicated that hydroxylation and N-dealkylation were the major metabolic pathways in 12 ADB-SCs. The effects of the core and tail on the metabolism of these ADB-SCs were studied using theoretical calculations. For N-dealkylation metabolism, the strong electron-withdrawing conjugative effect of the -N= moiety in the pyrazole ring, steric hindrance of the tail, and electronic effect of substituents on the tail significantly affected metabolism. Further, it changed the relative contents of N-dealkylation metabolites. For hydroxylation, the reaction types were inconsistent at different parts. For instance, the phenyl group of the core is electrophilic, and its electron cloud density determines whether the phenyl group can be hydroxylated at the specific metabolic sites. Meanwhile, hydroxylation of the neopentyl moiety of the linked group involves the oxidation of aliphatic C-H bonds, whereas amide-hydroxylamine tautomerism affects hydroxylation metabolism. When the alkyl chain in the tail contains functional groups (such as -F and >CC<), oxidative defluorination or dihydrodiol metabolites are produced. Taken together, we systematically determined d the effect of functional groups in the core and tail of ADB-SCs on their metabolism, validating confirmed the feasibility of ADB-SC metabolism prediction based on their structural characteristics.

Asunto(s)

Cannabinoides , Indazoles , Indoles , Microsomas Hepáticos , Espectrometría de Masas en Tándem , Cannabinoides/química , Cannabinoides/metabolismo , Cannabinoides/análisis , Humanos , Indazoles/química , Microsomas Hepáticos/metabolismo , Cromatografía Líquida de Alta Presión/métodos , Indoles/química , Indoles/metabolismo , Espectrometría de Masas en Tándem/métodos , Hidroxilación

RESUMEN

Bacterial pigments stand out as exceptional natural bioactive compounds with versatile functionalities. The pigments represent molecules from distinct chemical categories including terpenes, terpenoids, carotenoids, pyridine, pyrrole, indole, and phenazines, which are synthesized by diverse groups of bacteria. Their spectrum of physiological activities encompasses bioactive potentials that often confer fitness advantages to facilitate the survival of bacteria amid challenging environmental conditions. A large proportion of such pigments are produced by bacterial pathogens mostly as secondary metabolites. Their multifaceted properties augment potential applications in biomedical, food, pharmaceutical, textile, paint industries, bioremediation, and in biosensor development. Apart from possessing a less detrimental impact on health with environmentally beneficial attributes, tractable and scalable production strategies render bacterial pigments a sustainable option for novel biotechnological exploration for untapped discoveries. The review offers a comprehensive account of physiological role of pigments from bacterial pathogens, production strategies, and potential applications in various biomedical and biotechnological fields. Alongside, the prospect of combining bacterial pigment research with cutting-edge approaches like nanotechnology has been discussed to highlight future endeavours.

Asunto(s)

Bacterias , Pigmentos Biológicos , Pigmentos Biológicos/química , Pigmentos Biológicos/metabolismo , Bacterias/metabolismo , Biotecnología/métodos , Carotenoides/metabolismo , Carotenoides/química , Indoles/metabolismo , Indoles/química , Terpenos/metabolismo , Terpenos/química , Piridinas/metabolismo , Piridinas/química , Pirroles/metabolismo , Pirroles/química , Técnicas Biosensibles , Fenazinas/metabolismo , Fenazinas/química

RESUMEN

A Gram-stain-negative, endospore-forming, rod-shaped, indole-producing bacterial strain, designated YZC6T, was isolated from fermented cabbage. Strain YZC6T grew at 10-37  °C, pH 5.5-8.5, and with up to 2  % (w/v) NaCl. The major cellular fatty acids were C16 : 0 and C18 : 1 cis 11 dimethyl acetal. Phylogenetic analysis of the 16S rRNA gene revealed that strain YZC6T belonged to the genus Lacrimispora and was closely related to Lacrimispora aerotolerans DSM 5434T (98.3  % sequence similarity), Lacrimispora saccharolytica WM1T (98.1  %), and Lacrimispora algidixylanolytica SPL73T (98.1  %). The average nucleotide identity based on blast (below 87.8  %) and digital DNA-DNA hybridization (below 36.1 %) values between the novel isolate and its corresponding relatives showed that strain YZC6T could be readily distinguished from its closely related species. Based on genotypic, phenotypic, and chemotaxonomic data, a novel Lacrimispora species, Lacrimispora brassicae sp. nov., was proposed, with YZC6T as the type strain (=MAFF 212518T=JCM 32810T=DSM 112100T). This study also proposed Clostridium indicum Gundawar et al. 2019 as a later heterotypic synonym of Lacrimispora amygdalina (Parshina et al. 2003) Haas and Blanchard 2020 and Clostridium methoxybenzovorans Mechichi et al. 1999 as a later heterotypic synonym of Lacrimispora indolis (McClung and McCpy 1957) Haas and Blanchard 2020.

Asunto(s)

Técnicas de Tipificación Bacteriana , Brassica , ADN Bacteriano , Ácidos Grasos , Fermentación , Hibridación de Ácido Nucleico , Filogenia , ARN Ribosómico 16S , Análisis de Secuencia de ADN , ARN Ribosómico 16S/genética , Ácidos Grasos/análisis , Brassica/microbiología , ADN Bacteriano/genética , Composición de Base , Clostridiales/clasificación , Clostridiales/aislamiento & purificación , Clostridiales/genética , Indoles/metabolismo

RESUMEN

Nintedanib is used to treat idiopathic pulmonary fibrosis, systemic sclerosis, interstitial lung disease, and progressive fibrotic interstitial lung disease. It is primarily cleared via hepatic metabolism, hydrolysis, and glucuronidation. In addition, formation of the iminium ion, a possible reactive metabolite, was predicted based on the chemical structure of nintedanib. To obtain a hint which may help to clarify the cause of nintedanib-induced liver injury, we investigated whether iminium ions were formed in the human liver. To detect unstable iminium ions using liquid chromatography-tandem mass spectrometry (LC-MS/MS), potassium cyanide was added to the reaction mixture as a trapping agent. Human liver and intestinal microsomes were incubated with nintedanib in the presence of NADPH to form two iminium ion metabolites on the piperazine ring. Their formation is strongly inhibited by ketoconazole, a potent cytochrome P450 (CYP) 3A4 inhibitor. Among the recombinant P450s, only CYP3A4 formed cyanide adducts. The role of CYP3A4 was supported by the positive correlation between CYP3A4 protein abundance, as determined by LC-MS-based proteomics, and the formation of cyanide adducts in 25 individual human liver microsomes. In conclusion, we have demonstrated that iminium ion metabolites are formed from nintedanib by CYP3A4 as potential reactive metabolites.

Asunto(s)

Citocromo P-450 CYP3A , Indoles , Humanos , Indoles/metabolismo , Indoles/farmacología , Indoles/química , Citocromo P-450 CYP3A/metabolismo , Iminas/metabolismo , Iminas/farmacología , Microsomas Hepáticos/metabolismo , Microsomas Hepáticos/efectos de los fármacos , Espectrometría de Masas en Tándem , Iones/metabolismo

RESUMEN

The structure and surface physicochemical properties of anode play a crucial role in microbial fuel cells (MFCs). To enhance the enrichment of exoelectrogen and facilitate extracellular electron transfer (EET), a three-dimensional macroporous graphene aerogel with polydopamine coating was successfully introduced to modify carbon brush (PGA/CB). The three-dimensional graphene aerogel (GA) with micrometer pores improved the space utilization efficiency of microorganisms. Polydopamine (PDA) coating enhanced the physicochemical properties of the electrode surface by introducing abundant functional groups and nitrogen-containing active sites. MFCs equipped with PGA/CB anodes (PGA/CB-MFCs) demonstrated superior power generation compared to GA/CB-MFCs and CB-MFCs (MFCs with GA/CB and CB anodes respectively), including a 23.0 % and 30.1 % reduction in start-up time, and an increase in maximum power density by 2.43 and 1.24 times respectively. The higher bioelectrochemical activity exhibited by the biofilm of PGA/CB anode and the promoted riboflavin secretion by PGA modification imply the enhanced EET efficiency. 16S rRNA high-throughput sequence analysis of the biofilms revealed successful enrichment of Geobacter on PGA/CB anodes. These findings not only validate the positive impact of the synergistic effects between GA and PDA in promoting EET and improving MFC performance but also provide valuable insights for electrode design in other bioelectrochemical systems.

Asunto(s)

Fuentes de Energía Bioeléctrica , Electrodos , Grafito , Indoles , Polímeros , Indoles/química , Indoles/metabolismo , Fuentes de Energía Bioeléctrica/microbiología , Polímeros/química , Grafito/química , Transporte de Electrón , Biopelículas , Geles/química

RESUMEN

Artificial photoenzymes with novel catalytic modes not found in nature are in high demand; yet, they also present significant challenges in the field of biocatalysis. In this study, a chemogenetic modification strategy is developed to facilitate the rapid diversification of photoenzymes. This strategy integrates site-specific chemical conjugation of various artificial photosensitizers into natural protein cavities and the iterative mutagenesis in cell lysates. Through rounds of directed evolution, prominent visible-light-activatable photoenzyme variants were developed, featuring a thioxanthone chromophore. They successfully enabled the enantioselective [2 + 2] photocycloaddition of 2-carboxamide indoles, a class of UV-sensitive substrates that are traditionally challenging for known photoenzymes. Furthermore, the versatility of this photoenzyme is demonstrated in enantioselective whole-cell photobiocatalysis, enabling the efficient synthesis of enantioenriched cyclobutane-fused indoline tetracycles. These findings significantly expand the photophysical properties of artificial photoenzymes, a critical factor in enhancing their potential for harnessing excited-state reactivity in stereoselective transformations.

Asunto(s)

Reacción de Cicloadición , Estereoisomerismo , Indoles/química , Indoles/síntesis química , Indoles/metabolismo , Procesos Fotoquímicos , Biocatálisis , Evolución Molecular Dirigida , Fármacos Fotosensibilizantes/química , Fármacos Fotosensibilizantes/síntesis química , Luz , Escherichia coli/enzimología , Estructura Molecular

RESUMEN

Inter-cellular signaling, referred to as quorum sensing (QS), regulates the production of virulence factors in numerous gram-negative bacteria, such as the human pathogens Pseudomonas aeruginosa and Chromobacterium violaceum. QS inhibition may provide an opportunity for the treatment of bacterial infections. This represents the initial study to examine the antibiofilm and antivirulence capabilities of rose absolute and its primary component, phenylethyl alcohol. QS inhibition was assessed by examining extracellular exopolysaccharide synthesis, biofilm development, and swarming motility in P. aeruginosa PAO1, along with violacein production in C. violaceum ATCC 12472. Molecular docking analysis was conducted to explore the mechanism by which PEA inhibits QS. Our results indicate that rose absolute and PEA caused decrease in EPS production (60.5-33.5%), swarming motility (94.7-64.5%), and biofilm formation (98.53-55.5%) in the human pathogen P. aeruginosa PAO1. Violacein production decreased by 98.1% and 62.5% with an absolute (0.5 v/v %) and PEA (2 mM). Moreover, the molecular docking analysis revealed a promising competitive interaction between PEA and AHLs. Consequently, this study offers valuable insights into the potential of rose absolute and PEA as inhibitors of QS in P. aeruginosa and C. violaceum.

Asunto(s)

Biopelículas , Chromobacterium , Simulación del Acoplamiento Molecular , Alcohol Feniletílico , Pseudomonas aeruginosa , Percepción de Quorum , Percepción de Quorum/efectos de los fármacos , Pseudomonas aeruginosa/efectos de los fármacos , Pseudomonas aeruginosa/fisiología , Chromobacterium/efectos de los fármacos , Chromobacterium/fisiología , Biopelículas/efectos de los fármacos , Biopelículas/crecimiento & desarrollo , Alcohol Feniletílico/farmacología , Alcohol Feniletílico/análogos & derivados , Alcohol Feniletílico/química , Alcohol Feniletílico/metabolismo , Antibacterianos/farmacología , Antibacterianos/química , Indoles/farmacología , Indoles/metabolismo

RESUMEN

Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterized primarily by cognitive impairment. Recent investigations have highlighted the potential of nutritional interventions that target the gut-brain axis, such as probiotics and prebiotics, in forestalling the onset of AD. In this study, whole-genome sequencing was employed to identify xylan as the optimal carbon source for the tryptophan metabolism regulating probiotic Clostridium sporogenes (C. sporogenes). Subsequent in vivo studies demonstrated that administration of a synbiotic formulation comprising C. sporogenes (1 × 1010 CFU per day) and xylan (1%, w/w) over a duration of 30 days markedly enhanced cognitive performance and spatial memory faculties in the 5xFAD transgenic AD mouse model. The synbiotic treatment significantly reduced amyloid-ß (Aß) accumulation in the cortex and hippocampus of the brain. Importantly, synbiotic therapy substantially restored the synaptic ultrastructure in AD mice and suppressed neuroinflammatory responses. Moreover, the intervention escalated levels of the microbial metabolite indole-3-propionic acid (IPA) and augmented the relative prevalence of IPA-synthesizing bacteria, Lachnospira and Clostridium, while reducing the dominant bacteria in AD, such as Aquabacterium, Corynebacterium, and Romboutsia. Notably, synbiotic treatment also prevented the disruption of gut barrier integrity. Correlation analysis indicated a strong positive association between gut microbiota-generated IPA levels and behavioral changes. In conclusion, this study demonstrates that synbiotic supplementation significantly improves cognitive and intellectual deficits in 5xFAD mice, which could be partly attributed to enhanced IPA production by gut microbiota. These findings provide a theoretical basis for considering synbiotic therapy as a novel microbiota-targeted approach for the treatment of metabolic and neurodegenerative diseases.

Asunto(s)

Enfermedad de Alzheimer , Clostridium , Disfunción Cognitiva , Modelos Animales de Enfermedad , Microbioma Gastrointestinal , Indoles , Ratones Transgénicos , Simbióticos , Xilanos , Animales , Enfermedad de Alzheimer/terapia , Enfermedad de Alzheimer/metabolismo , Ratones , Simbióticos/administración & dosificación , Indoles/metabolismo , Disfunción Cognitiva/terapia , Disfunción Cognitiva/metabolismo , Xilanos/metabolismo , Xilanos/farmacología , Clostridium/metabolismo , Masculino , Péptidos beta-Amiloides/metabolismo , Humanos , Propionatos/metabolismo , Eje Cerebro-Intestino/fisiología

RESUMEN

Tryptophan is catabolized by gut microorganisms resulting in a wide range of metabolites implicated in both beneficial and adverse host effects. How gut microbial tryptophan metabolism is directed towards indole, associated with chronic kidney disease, or towards protective indolelactic acid (ILA) and indolepropionic acid (IPA) is unclear. Here we used in vitro culturing and animal experiments to assess gut microbial competition for tryptophan and the resulting metabolites in a controlled three-species defined community and in complex undefined human faecal communities. The generation of specific tryptophan-derived metabolites was not predominantly determined by the abundance of tryptophan-metabolizing bacteria, but rather by substrate-dependent regulation of specific metabolic pathways. Indole-producing Escherichia coli and ILA- and IPA-producing Clostridium sporogenes competed for tryptophan within the three-species community in vitro and in vivo. Importantly, fibre-degrading Bacteroides thetaiotaomicron affected this competition by cross-feeding monosaccharides to E. coli. This inhibited indole production through catabolite repression, thus making more tryptophan available to C. sporogenes, resulting in increased ILA and IPA production. The fibre-dependent reduction in indole was confirmed using human faecal cultures and faecal-microbiota-transplanted gnotobiotic mice. Our findings explain why consumption of fermentable fibres suppresses indole production but promotes the generation of other tryptophan metabolites associated with health benefits.

Asunto(s)

Clostridium , Fibras de la Dieta , Escherichia coli , Heces , Microbioma Gastrointestinal , Indoles , Triptófano , Triptófano/metabolismo , Animales , Humanos , Microbioma Gastrointestinal/fisiología , Fibras de la Dieta/metabolismo , Heces/microbiología , Ratones , Indoles/metabolismo , Escherichia coli/metabolismo , Clostridium/metabolismo , Vida Libre de Gérmenes , Propionatos/metabolismo , Interacciones Microbianas , Trasplante de Microbiota Fecal

RESUMEN

Centromere protein A (CENP-A), a centromere-specific histone H3 variant, is crucial for kinetochore positioning and chromosome segregation. However, its regulatory mechanism in human cells remains incompletely understood. A structure-activity relationship (SAR) study of the cell-cycle-arresting indole terpenoid mimic JP18 leads to the discovery of two more potent analogs, (+)-6-Br-JP18 and (+)-6-Cl-JP18. Tubulin is identified as a potential cellular target of these halogenated analogs by using the drug affinity responsive target stability (DARTS) based method. X-ray crystallography analysis reveals that both molecules bind to the colchicine-binding site of ß-tubulin. Treatment of human cells with microtubule-targeting agents (MTAs), including these two compounds, results in CENP-A accumulation by destabilizing Cdh1, a co-activator of the anaphase-promoting complex/cyclosome (APC/C) E3 ubiquitin ligase. This study establishes a link between microtubule dynamics and CENP-A accumulation using small-molecule tools and highlights the role of Cdh1 in CENP-A proteolysis.

Asunto(s)

Proteína A Centromérica , Microtúbulos , Proteolisis , Humanos , Antígenos CD , Cadherinas , Proteínas Cdh1/metabolismo , Proteínas Cdh1/genética , Proteína A Centromérica/metabolismo , Proteína A Centromérica/genética , Cristalografía por Rayos X/métodos , Indoles/metabolismo , Indoles/farmacología , Indoles/química , Microtúbulos/metabolismo , Microtúbulos/efectos de los fármacos , Proteolisis/efectos de los fármacos , Huso Acromático/metabolismo , Huso Acromático/efectos de los fármacos , Relación Estructura-Actividad

RESUMEN

Cysteine (Cys) plays an indispensable role as an antioxidant in the maintenance of bioredox homeostasis. We have constructed an efficient fluorescent probe Mito-Cys based on the binding of indole and naphthol. The acrylic ester group serves as a recognition switch for specific detection of Cys, which undergoes Michael addition and intramolecular cyclization reactions, thereby ensuring the chemical kinetics priority of Cys compared to other biothiols. The probe has good water solubility, large Stokes shift (137 nm), with a detection limit of 21.81 nM. In addition, cell imaging experiments have shown that the probe has excellent mitochondrial targeting ability (R = 0.902). The probe can distinguish between Cys, homocysteine (Hcy) and glutathione (GSH), and can detect Cys specifically and quickly (100 s) to ensure accurate quantitative analysis of Cys changes in cells. More importantly, the probe confirms that ferroptosis inducing factors trigger thiol starvation in mitochondria, which helps to gain a deeper understanding of the physiological and pathological functions related to Cys and ferroptosis.

Asunto(s)

Cisteína , Colorantes Fluorescentes , Mitocondrias , Pez Cebra , Pez Cebra/metabolismo , Cisteína/metabolismo , Cisteína/química , Mitocondrias/metabolismo , Mitocondrias/química , Colorantes Fluorescentes/química , Colorantes Fluorescentes/síntesis química , Humanos , Animales , Indoles/química , Indoles/metabolismo , Imagen Óptica , Estructura Molecular , Naftoles/química , Naftoles/síntesis química , Naftoles/metabolismo

RESUMEN

Microbiota tryptophan metabolism and the biosynthesis of indole derivatives play an important role in homeostasis and pathogenesis in the human body and can be affected by the gut microbiota. However, studies on the interplay between gut microbiota and tryptophan metabolites in patients undergoing dialysis are lacking. This study aimed to identify the gut microbiota, the indole pathway in tryptophan metabolism, and significant functional differences in ESRD patients with regular hemodialysis. We performed the shotgun metagenome sequencing of stool samples from 85 hemodialysis patients. Using the linear discriminant analysis effect size (LEfSe), we examined the composition of the gut microbiota and metabolic features across varying concentrations of tryptophan and indole metabolites. Higher tryptophan levels promoted tyrosine degradation I and pectin degradation I metabolic modules; lower tryptophan levels were associated with glutamate degradation I, fructose degradation, and valine degradation modules. Higher 3-indoxyl sulfate concentrations were characterized by alanine degradation I, anaerobic fatty acid beta-oxidation, sulfate reduction, and acetyl-CoA to crotonyl-CoA. Contrarily, lower 3-indoxyl sulfate levels were related to propionate production III, arabinoxylan degradation, the Entner-Doudoroff pathway, and glutamate degradation II. The present study provides a better understanding of the interaction between tryptophan, indole metabolites, and the gut microbiota as well as their gut metabolic modules in ESRD patients with regular hemodialysis.

Asunto(s)

Microbioma Gastrointestinal , Indoles , Diálisis Renal , Triptófano , Humanos , Triptófano/metabolismo , Indoles/metabolismo , Masculino , Femenino , Persona de Mediana Edad , Anciano , Fallo Renal Crónico/terapia , Fallo Renal Crónico/metabolismo , Fallo Renal Crónico/microbiología , Heces/microbiología , Redes y Vías Metabólicas , Adulto , Metagenoma

RESUMEN

To investigate the metabolic transformation of cyclopiazonic acid (CPA) in the liver of different species and to supplement accurate risk assessment information, the metabolism of CPA in liver microsomes from four animals and humans was studied using the ultra-high-performance liquid chromatography-quadrupole/time-of-flight method. The results showed that a total of four metabolites were obtained, and dehydrogenation, hydroxylation, methylation, and glucuronidation were identified as the main metabolic pathways of CPA. Rat liver microsomes exhibited the highest metabolic capacity for CPA, with dehydrogenated (C20H18N2O3) and glucuronic acid-conjugated (C26H28N2O10) metabolites identified in all liver microsomes except chicken, indicating significant species metabolic differences. Moreover, C20H18N2O3 was only detected in the incubation system with cytochromes P450 3A4 (CYP3A4). The hydroxylated (C20H20N2O4) and methylated (C21H22N2O3) metabolites were detected in all incubation systems except for the CYP2C9, with CYP3A4 demonstrating the strongest metabolic capacity. The "cocktail" probe drug method showed that CPA exhibited a moderate inhibitory effect on the CYP3A4 (IC50 value = 8.658 µM), indicating that the substrate had a negative effect on enzyme activity. Our results provide new insights to understand the biotransformation profile of CPA in animals and humans.

Asunto(s)

Indoles , Microsomas Hepáticos , Microsomas Hepáticos/metabolismo , Animales , Humanos , Indoles/metabolismo , Cromatografía Líquida de Alta Presión , Ratas , Pollos/metabolismo , Masculino , Perros , Espectrometría de Masas , Ratas Sprague-Dawley , Biotransformación , Ratones

RESUMEN

Indole is widely present in nature and contributes significantly to the smell of flowers and animal excretion. However, the odor perception mechanism for indole is unclear, despite previous reports suggesting that it activates the Olfr740 family of receptors. In this study, we successfully identified another receptor, Olfr205, that is responsive to indole. Molecular model construction and binding pocket analysis predicted that the A202 residue in transmembrane helix 5 of Olfr205 forms a crucial hydrogen bond with indole, facilitating receptor activation. Additionally, G112 in transmembrane helix 3 of the Olfr740 family is involved in indole activation of receptors. Finally, our mutant function assay showed that substitution of A202 in Olfr205 and G112 in Olfr740 with other amino acids significantly decreased the receptor response to indole, which provides robust evidence to confirm the docking results. In summary, our study is the first to reveal that Olfr205 is an olfactory receptor distinct from those in the Olfr740 family that is activated by indole. Moreover, these receptors display different indole-binding mechanisms. This study sheds light on molecular binding mechanisms and contributes to a deeper understanding of indole perception.

Asunto(s)

Indoles , Receptores Odorantes , Indoles/metabolismo , Indoles/química , Indoles/farmacología , Receptores Odorantes/metabolismo , Receptores Odorantes/genética , Receptores Odorantes/química , Animales , Humanos , Células HEK293 , Simulación del Acoplamiento Molecular , Secuencia de Aminoácidos , Sitios de Unión , Unión Proteica