RESUMEN
The emergence of drug-resistant tuberculosis has created an urgent need for new anti-tubercular agents. Here, we report the discovery of a series of macrolides called sequanamycins with outstanding in vitro and in vivo activity against Mycobacterium tuberculosis (Mtb). Sequanamycins are bacterial ribosome inhibitors that interact with the ribosome in a similar manner to classic macrolides like erythromycin and clarithromycin, but with binding characteristics that allow them to overcome the inherent macrolide resistance of Mtb. Structures of the ribosome with bound inhibitors were used to optimize sequanamycin to produce the advanced lead compound SEQ-9. SEQ-9 was efficacious in mouse models of acute and chronic TB as a single agent, and it demonstrated bactericidal activity in a murine TB infection model in combination with other TB drugs. These results support further investigation of this series as TB clinical candidates, with the potential for use in new regimens against drug-susceptible and drug-resistant TB.
Asunto(s)
Antituberculosos , Mycobacterium tuberculosis , Animales , Ratones , Antituberculosos/farmacología , Macrólidos , Farmacorresistencia Bacteriana , ClaritromicinaRESUMEN
Drug-resistant Pseudomonas aeruginosa (PA) poses an emerging threat to human health with urgent need for alternative therapeutic approaches. Here, we deciphered the B cell and antibody response to the virulence-associated type III secretion system (T3SS) in a cohort of patients chronically infected with PA. Single-cell analytics revealed a diverse B cell receptor repertoire directed against the T3SS needle-tip protein PcrV, enabling the production of monoclonal antibodies (mAbs) abrogating T3SS-mediated cytotoxicity. Mechanistic studies involving cryoelectron microscopy identified a surface-exposed C-terminal PcrV epitope as the target of highly neutralizing mAbs with broad activity against drug-resistant PA isolates. These anti-PcrV mAbs were as effective as treatment with conventional antibiotics in vivo. Our study reveals that chronically infected patients represent a source of neutralizing antibodies, which can be exploited as therapeutics against PA.
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Anticuerpos Antibacterianos , Anticuerpos Neutralizantes , Infecciones por Pseudomonas , Pseudomonas aeruginosa , Humanos , Anticuerpos Antibacterianos/farmacología , Microscopía por Crioelectrón , Inmunoglobulinas/metabolismo , Pseudomonas aeruginosa/efectos de los fármacos , Pseudomonas aeruginosa/fisiología , Infecciones por Pseudomonas/tratamiento farmacológicoRESUMEN
Drug-resistant bacterial pathogens pose an urgent public-health crisis. Here, we report the discovery, from microbial-extract screening, of a nucleoside-analog inhibitor that inhibits bacterial RNA polymerase (RNAP) and exhibits antibacterial activity against drug-resistant bacterial pathogens: pseudouridimycin (PUM). PUM is a natural product comprising a formamidinylated, N-hydroxylated Gly-Gln dipeptide conjugated to 6'-amino-pseudouridine. PUM potently and selectively inhibits bacterial RNAP in vitro, inhibits bacterial growth in culture, and clears infection in a mouse model of Streptococcus pyogenes peritonitis. PUM inhibits RNAP through a binding site on RNAP (the NTP addition site) and mechanism (competition with UTP for occupancy of the NTP addition site) that differ from those of the RNAP inhibitor and current antibacterial drug rifampin (Rif). PUM exhibits additive antibacterial activity when co-administered with Rif, exhibits no cross-resistance with Rif, and exhibits a spontaneous resistance rate an order-of-magnitude lower than that of Rif. PUM is a highly promising lead for antibacterial therapy.
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Antibacterianos/aislamiento & purificación , Antibacterianos/farmacología , ARN Polimerasas Dirigidas por ADN/antagonistas & inhibidores , Streptomyces/química , Animales , Antibacterianos/química , Bacterias/clasificación , Bacterias/efectos de los fármacos , Bacterias/crecimiento & desarrollo , ARN Polimerasas Dirigidas por ADN/química , Farmacorresistencia Bacteriana , Femenino , Células HeLa , Humanos , Ratones , Ratones Endogámicos ICR , Microbiología del Suelo , Infecciones Estreptocócicas/tratamiento farmacológico , Streptococcus pyogenes/efectos de los fármacos , Transcripción Genética/efectos de los fármacosRESUMEN
Human toll-like receptor 8 (TLR8) activation induces a potent T helper-1 (Th1) cell response critical for defense against intracellular pathogens, including protozoa. The receptor harbors two distinct binding sites, uridine and di- and/or trinucleotides, but the RNases upstream of TLR8 remain poorly characterized. We identified two endolysosomal endoribonucleases, RNase T2 and RNase 2, that act synergistically to release uridine from oligoribonucleotides. RNase T2 cleaves preferentially before, and RNase 2 after, uridines. Live bacteria, P. falciparum-infected red blood cells, purified pathogen RNA, and synthetic oligoribonucleotides all required RNase 2 and T2 processing to activate TLR8. Uridine supplementation restored RNA recognition in RNASE2-/- or RNASET2-/- but not RNASE2-/-RNASET2-/- cells. Primary immune cells from RNase T2-hypomorphic patients lacked a response to bacterial RNA but responded robustly to small-molecule TLR8 ligands. Our data identify an essential function of RNase T2 and RNase 2 upstream of TLR8 and provide insight into TLR8 activation.
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Endorribonucleasas/metabolismo , Monocitos/inmunología , Neutrófilos/inmunología , ARN Bacteriano/metabolismo , ARN Protozoario/metabolismo , Receptor Toll-Like 8/metabolismo , Sistemas CRISPR-Cas , Línea Celular , Endorribonucleasas/inmunología , Eritrocitos/inmunología , Eritrocitos/parasitología , Escherichia coli/química , Escherichia coli/inmunología , Edición Génica/métodos , Humanos , Listeria monocytogenes/química , Listeria monocytogenes/inmunología , Monocitos/microbiología , Monocitos/parasitología , Neutrófilos/microbiología , Neutrófilos/parasitología , Plasmodium falciparum/química , Plasmodium falciparum/inmunología , Cultivo Primario de Células , Estabilidad del ARN , ARN Bacteriano/inmunología , ARN Protozoario/inmunología , Serratia marcescens/química , Serratia marcescens/inmunología , Staphylococcus aureus/química , Staphylococcus aureus/inmunología , Streptococcus/química , Streptococcus/inmunología , Células THP-1 , Receptor Toll-Like 8/inmunologíaRESUMEN
Efflux of antibacterial compounds is a major mechanism for developing antimicrobial resistance. In the Gram-positive pathogen Staphylococcus aureus, QacA, a 14 transmembrane helix containing major facilitator superfamily antiporter, mediates proton-coupled efflux of mono and divalent cationic antibacterial compounds. In this study, we report the cryo-EM structure of QacA, with a single mutation D411N that improves homogeneity and retains efflux activity against divalent cationic compounds like dequalinium and chlorhexidine. The structure of substrate-free QacA, complexed to two single-domain camelid antibodies, was elucidated to a resolution of 3.6 Å. The structure displays an outward-open conformation with an extracellular helical hairpin loop (EL7) between transmembrane helices 13 and 14, which is conserved in a subset of DHA2 transporters. Removal of the EL7 hairpin loop or disrupting the interface formed between EL7 and EL1 compromises efflux activity. Chimeric constructs of QacA with a helical hairpin and EL1 grafted from other DHA2 members, LfrA and SmvA, restore activity in the EL7 deleted QacA revealing the allosteric and vital role of EL7 hairpin in antibacterial efflux in QacA and related members.
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Infecciones Estafilocócicas , Staphylococcus aureus , Humanos , Staphylococcus aureus/genética , Staphylococcus aureus/metabolismo , Microscopía por Crioelectrón , Proteínas Bacterianas/metabolismo , Proteínas de Transporte de Membrana/genética , Proteínas de Transporte de Membrana/química , Antibacterianos/farmacologíaRESUMEN
Cationic polymers have been identified as a promising type of antibacterial molecules, whose bioactivity can be tuned through structural modulation. Recent studies suggest that the placement of the cationic groups close to the core of the polymeric architecture rather than on appended side chains might improve both their bioactivity and selectivity for bacterial cells over mammalian cells. However, antibacterial main-chain cationic polymers are typically synthesized via polycondensations, which do not afford precise and uniform molecular design. Therefore, accessing main-chain cationic polymers with high degrees of molecular tunability hinges upon the development of controlled polymerizations tolerating cationic motifs (or cation progenitors) near the propagating species. Herein, we report the synthesis and ring-opening metathesis polymerization (ROMP) of N-methylpyridinium-fused norbornene monomers. The identification of reaction conditions leading to a well-controlled ROMP enabled structural diversification of the main-chain cationic polymers and a study of their bioactivity. This family of polyelectrolytes was found to be active against both Gram-negative (Escherichia coli) and Gram-positive (Methicillin-resistant Staphylococcus aureus) bacteria with minimal inhibitory concentrations as low as 25 µg/mL. Additionally, the molar mass of the polymers was found to impact their hemolytic activity with cationic polymers of smaller degrees of polymerization showing increased selectivity for bacteria over human red blood cells.
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Staphylococcus aureus Resistente a Meticilina , Polímeros , Animales , Humanos , Polímeros/química , Polimerizacion , Antibacterianos/farmacología , Antibacterianos/química , Norbornanos/química , Cationes , MamíferosRESUMEN
SUMMARYClostridioides difficile infection (CDI) is one of the major issues in nosocomial infections. This bacterium is constantly evolving and poses complex challenges for clinicians, often encountered in real-life scenarios. In the face of CDI, we are increasingly equipped with new therapeutic strategies, such as monoclonal antibodies and live biotherapeutic products, which need to be thoroughly understood to fully harness their benefits. Moreover, interesting options are currently under study for the future, including bacteriophages, vaccines, and antibiotic inhibitors. Surveillance and prevention strategies continue to play a pivotal role in limiting the spread of the infection. In this review, we aim to provide the reader with a comprehensive overview of epidemiological aspects, predisposing factors, clinical manifestations, diagnostic tools, and current and future prophylactic and therapeutic options for C. difficile infection.
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Clostridioides difficile , Infecciones por Clostridium , Humanos , Infecciones por Clostridium/epidemiología , Infecciones por Clostridium/prevención & control , Infecciones por Clostridium/terapia , Factores de Riesgo , Infección Hospitalaria/epidemiología , Infección Hospitalaria/prevención & control , Infección Hospitalaria/microbiología , Antibacterianos/uso terapéutico , Historia del Siglo XXIRESUMEN
Hemoglobin (Hb) has been identified in at least 14 molluscan taxa so far. Research spanning over 130 years on molluscan Hbs focuses on their genes, protein structures, functions, and evolution. Molluscan Hbs are categorized into single-, two-, and multiple-domain chains, including red blood cell, gill, and extracellular Hbs, based on the number of globin domains and their respective locations. These Hbs exhibit variation in assembly, ranging from monomeric and dimeric to higher-order multimeric forms. Typically, molluscan Hbs display moderately high oxygen affinity, weak cooperativity, and varying pH sensitivity. Hb's potential role in antimicrobial pathways could augment the immune defense of bivalves, which may be a complement to their lack of adaptive immunity. The role of Hb as a respiratory protein in bivalves likely originated from the substitution of hemocyanin. Molluscan Hbs demonstrate adaptive evolution in response to environmental changes via various strategies (e.g. increasing Hb types, multimerization, and amino acid residue substitutions at key sites), enhancing or altering functional properties for habitat adaptation. Concurrently, an increase in Hb assembly diversity, coupled with a downward trend in oxygen affinity, is observed during molluscan differentiation and evolution. Hb in Protobranchia, Heteroconchia, and Pteriomorphia bivalves originated from separate ancestors, with Protobranchia inheriting a relative ancient molluscan Hb gene. In bivalves, extracellular Hbs share a common origin, while gill Hbs likely emerged from convergent evolution. In summary, research on molluscan Hbs offers valuable insights into the origins, biological variations, and adaptive evolution of animal Hbs.
Asunto(s)
Hemoglobinas , Moluscos , Animales , Hemoglobinas/genética , Hemoglobinas/química , Hemoglobinas/metabolismo , Moluscos/genética , Moluscos/metabolismo , Oxígeno/metabolismoRESUMEN
Antibacterial resistance is one of the greatest threats to human health. The development of new therapeutics against bacterial pathogens has slowed drastically since the approvals of the first antibiotics in the early and mid-20th century. Most of the currently investigated drug leads are modifications of approved antibacterials, many of which are derived from natural products. In this review, we highlight the challenges, advancements and current standing of the clinical and preclinical antibacterial research pipeline. Additionally, we present novel strategies for rejuvenating the discovery process and advocate for renewed and enthusiastic investment in the antibacterial discovery pipeline.
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Productos Biológicos , Descubrimiento de Drogas , Humanos , Antibacterianos/farmacología , Antibacterianos/uso terapéutico , Bacterias/genética , Farmacorresistencia MicrobianaRESUMEN
The bacterial toxin CcdB (Controller of Cell death or division B) targets DNA Gyrase, an essential bacterial topoisomerase, which is also the molecular target for fluoroquinolones. Here, we present a short cell-penetrating 24-mer peptide, CP1-WT, derived from the Gyrase-binding region of CcdB and examine its effect on growth of Escherichia coli, Salmonella Typhimurium, Staphylococcus aureus and a carbapenem- and tigecycline-resistant strain of Acinetobacter baumannii in both axenic cultures and mouse models of infection. The CP1-WT peptide shows significant improvement over ciprofloxacin in terms of its in vivo therapeutic efficacy in treating established infections of S. Typhimurium, S. aureus and A. baumannii. The molecular mechanism likely involves inhibition of Gyrase or Topoisomerase IV, depending on the strain used. The study validates the CcdB binding site on bacterial DNA Gyrase as a viable and alternative target to the fluoroquinolone binding site.
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Antibacterianos , Staphylococcus aureus , Animales , Ratones , Staphylococcus aureus/genética , Staphylococcus aureus/metabolismo , Antibacterianos/farmacología , Girasa de ADN/química , Girasa de ADN/genética , Girasa de ADN/metabolismo , Topoisomerasa de ADN IV/genética , Topoisomerasa de ADN IV/metabolismo , Topoisomerasa de ADN IV/farmacología , Péptidos/farmacologíaRESUMEN
Rationale: Shorter time-to-antibiotics improves survival from sepsis, particularly among patients in shock. There may be other subgroups for whom faster antibiotics are particularly beneficial.Objectives: Identify patient characteristics associated with greater benefit from shorter time-to-antibiotics.Methods: Observational cohort study of patients hospitalized with community-onset sepsis at 173 hospitals and treated with antimicrobials within 12 hours. We used three approaches to evaluate heterogeneity of benefit from shorter time-to-antibiotics: 1) conditional average treatment effects of shorter (⩽3 h) versus longer (>3-12 h) time-to-antibiotics on 30-day mortality using multivariable Poisson regression; 2) causal forest to identify characteristics associated with greatest benefit from shorter time-to-antibiotics; and 3) logistic regression with time-to-antibiotics modeled as a spline.Measurements and Main Results: Among 273,255 patients with community-onset sepsis, 131,094 (48.0%) received antibiotics within 3 hours. In Poisson models, shorter time-to-antibiotics was associated with greater absolute mortality reduction among patients with metastatic cancer (5.0% [95% confidence interval; CI: 4.3-5.7] vs. 0.4% [95% CI: 0.2-0.6] for patients without cancer, P < 0.001); patients with shock (7.0% [95% CI: 5.8-8.2%] vs. 2.8% [95% CI: 2.7-3.5%] for patients without shock, P = 0.005); and patients with more acute organ dysfunctions (4.8% [95% CI: 3.9-5.6%] for three or more dysfunctions vs. 0.5% [95% CI: 0.3-0.8] for one dysfunction, P < 0.001). In causal forest, metastatic cancer and shock were associated with greatest benefit from shorter time-to-antibiotics. Spline analysis confirmed differential nonlinear associations of time-to-antibiotics with mortality in patients with metastatic cancer and shock.Conclusions: In patients with community-onset sepsis, the mortality benefit of shorter time-to-antibiotics varied by patient characteristics. These findings suggest that shorter time-to-antibiotics for sepsis is particularly important among patients with cancer and/or shock.
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Neoplasias , Sepsis , Choque Séptico , Humanos , Antibacterianos/uso terapéutico , Sepsis/terapia , Estudios de Cohortes , Estudios Retrospectivos , Mortalidad HospitalariaRESUMEN
Rationale: Pneumonia is a frequent and feared complication in intubated critically ill patients. Tissue concentrations of antimicrobial drugs need to be sufficiently high to treat the infection and also prevent development of bacterial resistance. It is uncertain whether pulmonary inflammation and injury affect antimicrobial drug penetration into lung tissue.Objectives: To determine and compare tissue and BAL fluid concentrations of ceftaroline fosamil and linezolid in a model of unilateral acute lung injury in pigs and to evaluate whether dose adjustment is necessary to reach sufficient antimicrobial concentrations in injured lung tissue.Methods: After induction of unilateral acute lung injury, ceftaroline fosamil and linezolid were administered intravenously. Drug concentrations were measured in lung tissue through microdialysis and in blood and BAL fluid samples during the following 8 hours. The primary endpoint was the tissue concentration area under the concentration curve in the first 8 hours (AUC0-8 h) of the two antimicrobial drugs.Measurements and Main Results: In 10 pigs, antimicrobial drug concentrations were higher in inflamed and injured lung tissue compared with those in uninflamed and uninjured lung tissue (median ceftaroline fosamil AUC0-8 h [and interquartile range] = 26.7 mg â h â L-1 [19.7-39.0] vs. 16.0 mg â h â L-1 [13.6-19.9], P = 0.02; median linezolid AUC0-8 h 76.0 mg â h â L-1 [68.1-96.0] vs. 54.6 mg â h â L-1 [42.7-60.9], P = 0.01), resulting in a longer time above the minimal inhibitory concentration and in higher peak concentrations and dialysate/plasma ratios. Penetration into BAL fluid was excellent for both antimicrobials, but without left-to-right differences (ceftaroline fosamil, P = 0.78; linezolid, P = 1.00).Conclusions: Tissue penetration of two commonly used antimicrobial drugs for pneumonia is enhanced by early lung tissue inflammation and injury, resulting in longer times above the minimal inhibitory concentration. Thus, lung tissue inflammation ameliorates antimicrobial drug penetration during the acute phase.
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Lesión Pulmonar Aguda , Antiinfecciosos , Neumonía , Humanos , Animales , Porcinos , Linezolid/uso terapéutico , Antibacterianos/efectos adversos , Antiinfecciosos/uso terapéutico , Ceftarolina , Neumonía/tratamiento farmacológico , Neumonía/inducido químicamente , Inflamación/tratamiento farmacológico , Inflamación/inducido químicamente , Pulmón , Lesión Pulmonar Aguda/tratamiento farmacológico , Lesión Pulmonar Aguda/inducido químicamenteRESUMEN
The application of dyes to understanding the aetiology of infection inspired antimicrobial chemotherapy and the first wave of antibacterial drugs. The second wave of antibacterial drug discovery was driven by rapid discovery of natural products, now making up 69% of current antibacterial drugs. But now with the most prevalent natural products already discovered, â¼107 new soil-dwelling bacterial species must be screened to discover one new class of natural product. Therefore, instead of a third wave of antibacterial drug discovery, there is now a discovery bottleneck. Unlike natural products which are curated by billions of years of microbial antagonism, the vast synthetic chemical space still requires artificial curation through the therapeutics science of antibacterial drugs - a systematic understanding of how small molecules interact with bacterial physiology, effect desired phenotypes, and benefit the host. Bacterial molecular genetics can elucidate pathogen biology relevant to therapeutics development, but it can also be applied directly to understanding mechanisms and liabilities of new chemical agents with new mechanisms of action. Therefore, the next phase of antibacterial drug discovery could be enabled by integrating chemical expertise with systematic dissection of bacterial infection biology. Facing the ambitious endeavour to find new molecules from nature or new-to-nature which cure bacterial infections, the capabilities furnished by modern chemical biology and molecular genetics can be applied to prospecting for chemical modulators of new targets which circumvent prevalent resistance mechanisms.
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Antibacterianos , Bacterias , Descubrimiento de Drogas , Antibacterianos/farmacología , Antibacterianos/química , Descubrimiento de Drogas/métodos , Bacterias/genética , Bacterias/efectos de los fármacos , Bacterias/metabolismo , Humanos , Productos Biológicos/farmacología , Productos Biológicos/química , Productos Biológicos/metabolismo , Infecciones Bacterianas/tratamiento farmacológico , Infecciones Bacterianas/microbiologíaRESUMEN
Because of the extremely complexed microenvironment of drug-resistant bacterial infection, nanomaterials with both bactericidal and immuno-modulating activities are undoubtedly the ideal modality for overcoming drug resistance. Herein, we precisely engineered the surface chemistry of selenium nanoparticles (SeNPs) using neutral (polyvinylpyrrolidone-PVP), anionic (letinan-LET) and cationic (chitosan-CS) surfactants. It was found that surface chemistry greatly influenced the bioactivities of functionalized SeNPs, their interactions with methicillin-resistant Staphylococcus aureus (MRSA), immune cells and metabolisms. LET-functionalized SeNPs with distinct metabolisms exhibited the best inhibitory efficacy compared to other kinds of SeNPs against MRSA through inducing robust ROS generation and damaging bacterial cell wall. Meanwhile, only LET-SeNPs could effectively activate natural kill (NK) cells, and enhance the phagocytic capability of macrophages and its killing activity against bacteria. Furthermore, in vivo studies suggested that LET-SeNPs treatment highly effectively combated MRSA infection and promoted wound healing by triggering much more mouse NK cells, CD8+ and CD4+ T lymphocytes infiltrating into the infected area at the early stage to efficiently eliminate MRSA in the mouse model. This study demonstrates that the novel functionalized SeNP with dual functions could serve as an effective antibacterial agent and could guide the development of next generation antibacterial agents.
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Antibacterianos , Staphylococcus aureus Resistente a Meticilina , Nanopartículas , Selenio , Infecciones Estafilocócicas , Staphylococcus aureus Resistente a Meticilina/efectos de los fármacos , Animales , Selenio/química , Selenio/farmacología , Ratones , Antibacterianos/farmacología , Antibacterianos/administración & dosificación , Antibacterianos/química , Infecciones Estafilocócicas/tratamiento farmacológico , Infecciones Estafilocócicas/inmunología , Infecciones Estafilocócicas/microbiología , Nanopartículas/química , Células Asesinas Naturales/inmunología , Células Asesinas Naturales/efectos de los fármacos , Macrófagos/efectos de los fármacos , Macrófagos/inmunología , Macrófagos/microbiología , Humanos , Modelos Animales de Enfermedad , Propiedades de Superficie , Pruebas de Sensibilidad MicrobianaRESUMEN
Although lacking an adaptive immune system and often living in habitats with dense and diverse bacterial populations, marine invertebrates thrive in the presence of potentially challenging microbial pathogens. However, the mechanisms underlying this resistance remain largely unexplored and promise to reveal novel strategies of microbial resistance. Here, we provide evidence that a mud-dwelling clam, Meretrix petechialis, synthesizes, stores, and secretes the antibiotic erythromycin. Liquid chromatography coupled with mass spectrometry, immunocytochemistry, fluorescence in situ hybridization, RNA interference, and enzyme-linked immunosorbent assay revealed that this potent macrolide antimicrobial, thought to be synthesized only by microorganisms, is produced by specific mucus-rich cells beneath the clam's mantle epithelium, which interfaces directly with the bacteria-rich environment. The antibacterial activity was confirmed by bacteriostatic assay. Genetic, ontogenetic, phylogenetic and genomic evidence, including genotypic segregation ratios in a family of full siblings, gene expression in clam larvae, phylogenetic tree, and synteny conservation in the related genome region further revealed that the genes responsible for erythromycin production are of animal origin. The detection of this antibiotic in another clam species showed that the production of this macrolide is not exclusive to M. petechialis and may be a common strategy among marine invertebrates. The finding of erythromycin production by a marine invertebrate offers a striking example of convergent evolution in secondary metabolite synthesis between the animal and bacterial domains. These findings open the possibility of engineering-animal tissues for the localized production of an antibacterial secondary metabolite.
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Bivalvos , Eritromicina , Animales , Eritromicina/farmacología , Filogenia , Hibridación Fluorescente in Situ , Bivalvos/genética , Antibacterianos/farmacología , MacrólidosRESUMEN
In gram-negative bacteria, lipoproteins are vital structural components of the outer membrane (OM) and crucial elements of machineries central to the physiology of the cell envelope. A dedicated apparatus, the Lol system, is required for the correct localization of OM lipoproteins and is essential for viability. The periplasmic chaperone LolA is central to this trafficking pathway, accepting triacylated lipoproteins from the inner membrane transporter LolCDE, before carrying them across the periplasm to the OM receptor LolB. Here, we report a crystal structure of liganded LolA, generated in vivo, revealing the molecular details of lipoprotein association. The structure highlights how LolA, initially primed to receive lipoprotein by interaction with LolC, further opens to accommodate the three ligand acyl chains in a precise conformation within its cavity. LolA forms extensive interactions with the acyl chains but not with any residue of the cargo, explaining the chaperone's ability to transport structurally diverse lipoproteins. Structural characterization of a ligandedLolA variant incapable of lipoprotein release reveals aberrant association, demonstrating the importance of the LolCDE-coordinated, sequential opening of LolA for inserting lipoprotein in a manner productive for subsequent trafficking. Comparison with existing structures of LolA in complex with LolC or LolCDE reveals substantial overlap of the lipoprotein and LolC binding sites within the LolA cavity, demonstrating that insertion of lipoprotein acyl chains physically disengages the chaperone protein from the transporter by perturbing interaction with LolC. Taken together, our data provide a key step toward a complete understanding of a fundamentally important trafficking pathway.
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Proteínas de Escherichia coli , Proteínas de Unión Periplasmáticas , Transporte de Proteínas , Proteínas de la Membrana Bacteriana Externa/genética , Proteínas de la Membrana Bacteriana Externa/metabolismo , Proteínas Portadoras/metabolismo , Escherichia coli/genética , Escherichia coli/metabolismo , Proteínas de Escherichia coli/química , Proteínas de Escherichia coli/genética , Proteínas de Escherichia coli/metabolismo , Ligandos , Lipoproteínas/metabolismo , Modelos Moleculares , Chaperonas Moleculares/genética , Chaperonas Moleculares/metabolismo , Periplasma/metabolismo , Proteínas de Unión Periplasmáticas/química , Proteínas de Unión Periplasmáticas/genética , Proteínas de Unión Periplasmáticas/metabolismo , Estructura Terciaria de Proteína , Transporte de Proteínas/genéticaRESUMEN
BACKGROUND: Pangolins are the only mammals that have overlapping scales covering most of their bodies, and they play a crucial role in the ecosystem, biological research, and human health and disease. Previous studies indicated pangolin scale might provide an important mechanical defense to themselves. The origin and exact functions of this unique trait remain a mystery. Using a multi-omics analysis approach, we report a novel functional explanation for how mammalian scales can provide host-pathogen defense. RESULTS: Our data suggest that pangolin scales have a sophisticated structure that could potentially trap pathogens. We identified numerous proteins and metabolites exhibiting antimicrobial activity, which could suggest a role for scales in pathogen defense. Notably, we found evidence suggesting the presence of exosomes derived from diverse cellular origins, including mesenchymal stem cells, immune cells, and keratinocytes. This observation suggests a complex interplay where various cell types may contribute to the release of exosomes and antimicrobial compounds at the interface between scales and viable tissue. These findings indicate that pangolin scales may serve as a multifaceted defense system, potentially contributing to innate immunity. Comparisons with human nail and hair revealed pangolin-specific proteins that were enriched in functions relating to sensing, immune responses, neutrophil degranulation, and stress responses. We demonstrated the antimicrobial activity of key pangolin scale components on pathogenic bacteria by antimicrobial assays. CONCLUSIONS: This study identifies a potential role of pangolin scales and implicates scales, as possible determinants of pathogen defense due to their structure and contents. We indicate for the first time the presence of exosomes in pangolin scales and propose the new functions of scales and their mechanisms. This new mechanism could have implications for multiple fields, including providing interesting new research directions and important insights that can be useful for synthesizing and implementing new biomimetic antimicrobial approaches.
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Inmunidad Innata , Pangolines , Animales , Humanos , Interacciones Huésped-Patógeno/inmunología , Adaptación FisiológicaRESUMEN
Wound infections, especially those caused by pathogenic bacteria, present a considerable public health concern due to associated complications and poor therapeutic outcomes. Herein, we developed antibacterial nanoparticles, namely, PGTP, by coordinating guanidine derivatives with a porphyrin-based sonosensitizer. The synthesized PGTP nanoparticles, characterized by their strong positive charge, effectively disrupted the bacterial biosynthesis process through charge interference, demonstrating efficacy against both Gram-negative and Gram-positive bacteria. Additionally, PGTP nanoparticles generated reactive oxygen species under ultrasound stimulation, resulting in the disruption of biofilm integrity and efficient elimination of pathogens. RNA-seq analysis unveiled the detailed mechanism of wound healing, revealing that PGTP nanoparticles, when coupled with ultrasound, impair bacterial metabolism by interfering with the synthesis and transcription of amino acids. This study presents a novel approach to combatting wound infections through ultrasound-driven charge-interfering therapy, facilitated by advanced antibacterial nanomaterials.
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Antibacterianos , Biopelículas , Nanopartículas , Infección de Heridas , Antibacterianos/farmacología , Antibacterianos/química , Antibacterianos/uso terapéutico , Infección de Heridas/tratamiento farmacológico , Infección de Heridas/microbiología , Nanopartículas/química , Nanopartículas/uso terapéutico , Biopelículas/efectos de los fármacos , Animales , Ratones , Ondas Ultrasónicas , Especies Reactivas de Oxígeno/metabolismo , Cicatrización de Heridas/efectos de los fármacos , Humanos , Porfirinas/química , Porfirinas/farmacología , Porfirinas/uso terapéutico , Terapia por Ultrasonido/métodos , Bacterias Grampositivas/efectos de los fármacos , Bacterias Gramnegativas/efectos de los fármacosRESUMEN
Halide perovskite nanocrystals (HPNCs) have emerged as promising materials for various light harvesting applications due to their exceptional optical and electronic properties. However, their inherent instability in water and biological fluids has limited their use as photocatalysts in the aqueous phase. In this study, we present highly water-stable SiO2-coated HPNCs as efficient photocatalysts for antimicrobial applications. The double SiO2 layer coating method confers long-term structural and optical stability to HPNCs in water, while the in situ synthesis of lead- and bismuth-based perovskite NCs into the SiO2 shell enhances their versatility and tunability. We demonstrate that the substantial generation of singlet oxygen via energy transfer from HPNCs enables efficient photoinduced antibacterial efficacy under aqueous conditions. More than 90% of Escherichia coli was inactivated under mild visible light irradiation for 6 h. The excellent photocatalytic antibacterial performance suggests that SiO2-coated HPNCs hold great potential for various aqueous phase photocatalytic applications.
RESUMEN
Phyllosilicates-based nanomaterials, particularly iron-rich vermiculite (VMT), have wide applications in biomedicine. However, the lack of effective methods to activate the functional layer covered by the external inert layer limits their future applications. Herein, we report a mineral phase reconfiguration strategy to prepare novel nanozymes by a molten salt method. The peroxidase-like activity of the VMT reconfiguration nanozyme is 10 times that of VMT, due to the electronic structure change of iron in VMT. Density-functional theory calculations confirmed that the upward shifted d-band center of the VMT reconfiguration nanozyme promoted the adsorption of H2O2 on the active iron sites and significantly elongated the O-O bond lengths. The reconfiguration nanozyme exhibited nearly 100% antibacterial activity toward Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), much higher than that of VMT (E. coli 10%, S. aureus 21%). This work provides new insights for the rational design of efficient bioactive phyllosilicates-based nanozyme.