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1.
Nat Commun ; 11(1): 4948, 2020 10 02.
Artigo em Inglês | MEDLINE | ID: mdl-33009415

RESUMO

The tripartite multidrug efflux system MexAB-OprM is a major actor in Pseudomonas aeruginosa antibiotic resistance by exporting a large variety of antimicrobial compounds. Crystal structures of MexB and of its Escherichia coli homolog AcrB had revealed asymmetric trimers depicting a directional drug pathway by a conformational interconversion (from Loose and Tight binding pockets to Open gate (LTO) for drug exit). It remains unclear how MexB acquires its LTO form. Here by performing functional and cryo-EM structural investigations of MexB at various stages of the assembly process, we unveil that MexB inserted in lipid membrane is not set for active transport because it displays an inactive LTC form with a Closed exit gate. In the tripartite complex, OprM and MexA form a corset-like platform that converts MexB into the active form. Our findings shed new light on the resistance nodulation cell division (RND) cognate partners which act as allosteric factors eliciting the functional drug extrusion.


Assuntos
Antibacterianos/metabolismo , Proteínas da Membrana Bacteriana Externa/metabolismo , Chaperonas Moleculares/metabolismo , Pseudomonas aeruginosa/metabolismo , Regulação Alostérica , Proteínas da Membrana Bacteriana Externa/química , Proteínas da Membrana Bacteriana Externa/ultraestrutura , Transporte Biológico , Modelos Moleculares , Domínios Proteicos
2.
Nat Commun ; 11(1): 4157, 2020 08 19.
Artigo em Inglês | MEDLINE | ID: mdl-32814767

RESUMO

Swarming is a form of collective bacterial motion enabled by flagella on the surface of semi-solid media. Swarming populations exhibit non-genetic or adaptive resistance to antibiotics, despite sustaining considerable cell death. Here, we show that antibiotic-induced death of a sub-population benefits the swarm by enhancing adaptive resistance in the surviving cells. Killed cells release a resistance-enhancing factor that we identify as AcrA, a periplasmic component of RND efflux pumps. The released AcrA interacts on the surface of live cells with an outer membrane component of the efflux pump, TolC, stimulating drug efflux and inducing expression of other efflux pumps. This phenomenon, which we call 'necrosignaling', exists in other Gram-negative and Gram-positive bacteria and displays species-specificity. Given that adaptive resistance is a known incubator for evolving genetic resistance, our findings might be clinically relevant to the rise of multidrug resistance.


Assuntos
Antibacterianos/metabolismo , Bactérias/metabolismo , Proteínas de Bactérias/metabolismo , Resistência Microbiana a Medicamentos/fisiologia , Transdução de Sinais/fisiologia , Adaptação Fisiológica/fisiologia , Antibacterianos/farmacologia , Bactérias/classificação , Proteínas da Membrana Bacteriana Externa/metabolismo , Bactérias Gram-Negativas/classificação , Bactérias Gram-Negativas/metabolismo , Bactérias Gram-Positivas/classificação , Bactérias Gram-Positivas/metabolismo , Viabilidade Microbiana/efeitos dos fármacos , Periplasma/metabolismo , Especificidade da Espécie
3.
PLoS Comput Biol ; 16(8): e1008106, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32797079

RESUMO

Antibiotic resistance is rising and we urgently need to gain a better quantitative understanding of how antibiotics act, which in turn would also speed up the development of new antibiotics. Here, we describe a computational model (COMBAT-COmputational Model of Bacterial Antibiotic Target-binding) that can quantitatively predict antibiotic dose-response relationships. Our goal is dual: We address a fundamental biological question and investigate how drug-target binding shapes antibiotic action. We also create a tool that can predict antibiotic efficacy a priori. COMBAT requires measurable biochemical parameters of drug-target interaction and can be directly fitted to time-kill curves. As a proof-of-concept, we first investigate the utility of COMBAT with antibiotics belonging to the widely used quinolone class. COMBAT can predict antibiotic efficacy in clinical isolates for quinolones from drug affinity (R2>0.9). To further challenge our approach, we also do the reverse: estimate the magnitude of changes in drug-target binding based on antibiotic dose-response curves. We overexpress target molecules to infer changes in antibiotic-target binding from changes in antimicrobial efficacy of ciprofloxacin with 92-94% accuracy. To test the generality of our approach, we use the beta-lactam ampicillin to predict target molecule occupancy at MIC from antimicrobial action with 90% accuracy. Finally, we apply COMBAT to predict antibiotic concentrations that can select for resistance due to novel resistance mutations. Using ciprofloxacin and ampicillin as well defined test cases, our work demonstrates that drug-target binding is a major predictor of bacterial responses to antibiotics. This is surprising because antibiotic action involves many additional effects downstream of drug-target binding. In addition, COMBAT provides a framework to inform optimal antibiotic dose levels that maximize efficacy and minimize the rise of resistant mutants.


Assuntos
Antibacterianos , Biologia Computacional/métodos , Desenvolvimento de Medicamentos/métodos , Quinolonas , Antibacterianos/química , Antibacterianos/metabolismo , Antibacterianos/farmacologia , Relação Dose-Resposta a Droga , Farmacorresistência Bacteriana/efeitos dos fármacos , Enterobacteriaceae/efeitos dos fármacos , Infecções por Enterobacteriaceae/microbiologia , Humanos , Testes de Sensibilidade Microbiana , Modelos Biológicos , Quinolonas/administração & dosagem , Quinolonas/química , Quinolonas/metabolismo , Quinolonas/farmacologia
4.
Proc Natl Acad Sci U S A ; 117(32): 19446-19454, 2020 08 11.
Artigo em Inglês | MEDLINE | ID: mdl-32723829

RESUMO

Antimicrobial peptides are important candidates for developing new classes of antibiotics because of their potency against antibiotic-resistant pathogens. Current research focuses on topical applications and it is unclear how to design peptides with systemic efficacy. To address this problem, we designed two potent peptides by combining database-guided discovery with structure-based design. When bound to membranes, these two short peptides with an identical amino acid composition can adopt two distinct amphipathic structures: A classic horizontal helix (horine) and a novel vertical spiral structure (verine). Their horizontal and vertical orientations on membranes were determined by solid-state 15N NMR data. While horine was potent primarily against gram-positive pathogens, verine showed broad-spectrum antimicrobial activity. Both peptides protected greater than 80% mice from infection-caused deaths. Moreover, horine and verine also displayed significant systemic efficacy in different murine models comparable to conventional antibiotics. In addition, they could eliminate resistant pathogens and preformed biofilms. Significantly, the peptides showed no nephrotoxicity to mice after intraperitoneal or intravenous administration for 1 wk. Our study underscores the significance of horine and verine in fighting drug-resistant pathogens.


Assuntos
Antibacterianos/química , Antibacterianos/farmacologia , Peptídeos Catiônicos Antimicrobianos/química , Peptídeos Catiônicos Antimicrobianos/farmacologia , Sequência de Aminoácidos , Animais , Antibacterianos/metabolismo , Antibacterianos/uso terapêutico , Peptídeos Catiônicos Antimicrobianos/metabolismo , Peptídeos Catiônicos Antimicrobianos/uso terapêutico , Bactérias/efeitos dos fármacos , Bactérias/crescimento & desenvolvimento , Infecções Bacterianas/tratamento farmacológico , Biofilmes/efeitos dos fármacos , Biofilmes/crescimento & desenvolvimento , Membrana Celular/metabolismo , Bases de Dados de Proteínas , Desenho de Fármacos , Farmacorresistência Bacteriana/efeitos dos fármacos , Humanos , Interações Hidrofóbicas e Hidrofílicas , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Testes de Sensibilidade Microbiana , Relação Estrutura-Atividade , Resultado do Tratamento
5.
Proc Natl Acad Sci U S A ; 117(32): 19517-19527, 2020 08 11.
Artigo em Inglês | MEDLINE | ID: mdl-32727901

RESUMO

Oxidative damage to DNA is a threat to the genomic integrity and coding accuracy of the chromosomes of all living organisms. Guanine is particularly susceptible to oxidation, and 8-oxo-dG (OG), when produced in situ or incorporated by DNA polymerases, is highly mutagenic due to mispairing with adenine. In many bacteria, defense against OG depends on MutT enzymes, which sanitize OG in the nucleotide pool, and the MutM/Y system, which counteracts OG in chromosomal DNA. In Escherichia coli, antibiotic lethality has been linked to oxidative stress and the downstream consequences of OG processing. However, in mycobacteria, the role of these systems in genomic integrity and antibiotic lethality is not understood, in part because mycobacteria encode four MutT enzymes and two MutMs, suggesting substantial redundancy. Here, we definitively probe the role of OG handling systems in mycobacteria. We find that, although MutT4 is the only MutT enzyme required for resistance to oxidative stress, this effect is not due to OG processing. We find that the dominant system that defends against OG-mediated mutagenesis is MutY/MutM1, and this system is dedicated to in situ chromosomal oxidation rather than correcting OG incorporated by accessory polymerases (DinB1/DinB2/DinB3/DnaE2). In addition, we uncover that mycobacteria resist antibiotic lethality through nucleotide sanitization by MutTs, and in the absence of this system, accessory DNA polymerases and MutY/M contribute to antibiotic-induced lethality. These results reveal a complex, multitiered system of OG handling in mycobacteria with roles in oxidative stress resistance, mutagenesis, and antibiotic lethality.


Assuntos
Antibacterianos/metabolismo , Cromossomos Bacterianos/metabolismo , Reparo do DNA/genética , Mycobacterium/genética , Estresse Oxidativo , 8-Hidroxi-2'-Desoxiguanosina/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Dano ao DNA , Tolerância a Medicamentos , Mutagênese , Mutação , Mycobacterium/crescimento & desenvolvimento , Mycobacterium/metabolismo , Oxirredução
6.
J Environ Sci Health B ; 55(9): 854-863, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32648501

RESUMO

Tylosin fermentation dregs (TFDs) are biosolid waste of antibiotics tylosin production process which contain nutritious components and may be recycled as soil amendments. However, the specific ecological safety of TFDs from the perspective of bacterial resistance in soil microenvironment is not fully explored. In the present study, a series of replicated lab-scale work were performed using the simulated fertilization to gain insight into the potential environmental effects and risks of macrolide antibiotic resistance genes (ARGs) and the soil microbial communities composition via quantitative PCR and 16S rRNA sequencing following the TFDs land application as the soil amendments. The results showed that bio-processes might play an important role in the decomposition of tylosin which degraded above 90% after 20 days in soil. The application of TFDs might induce the development of antibiotic-resistant bacteria, change soil environment and reduce the microbial diversity. Though the abundances of macrolide ARGs exhibited a decreasing trend following the tylosin degradation, other components in TFDs may have a lasting impact on both macrolide ARGs abundance and soil bacterial communities. Thus, this study pointed out the fate of TFDs on soil ecological environment when directly applying into soil, and provide valuable scientific basis for TFDs management.


Assuntos
Antibacterianos/metabolismo , Resistência Microbiana a Medicamentos/genética , Fertilizantes , Microbiota/efeitos dos fármacos , Microbiologia do Solo , Tilosina/metabolismo , Biodegradação Ambiental , Indústria Farmacêutica , Fermentação , Macrolídeos/farmacologia , Microbiota/genética , RNA Ribossômico 16S/genética
7.
Proc Natl Acad Sci U S A ; 117(29): 17011-17018, 2020 07 21.
Artigo em Inglês | MEDLINE | ID: mdl-32636271

RESUMO

Few antibiotics are effective against Acinetobacter baumannii, one of the most successful pathogens responsible for hospital-acquired infections. Resistance to chlorhexidine, an antiseptic widely used to combat A. baumannii, is effected through the proteobacterial antimicrobial compound efflux (PACE) family. The prototype membrane protein of this family, AceI (Acinetobacter chlorhexidine efflux protein I), is encoded for by the aceI gene and is under the transcriptional control of AceR (Acinetobacter chlorhexidine efflux protein regulator), a LysR-type transcriptional regulator (LTTR) protein. Here we use native mass spectrometry to probe the response of AceI and AceR to chlorhexidine assault. Specifically, we show that AceI forms dimers at high pH, and that binding to chlorhexidine facilitates the functional form of the protein. Changes in the oligomerization of AceR to enable interaction between RNA polymerase and promoter DNA were also observed following chlorhexidine assault. Taken together, these results provide insight into the assembly of PACE family transporters and their regulation via LTTR proteins on drug recognition and suggest potential routes for intervention.


Assuntos
Acinetobacter baumannii , Antibacterianos , Proteínas de Bactérias , Clorexidina , Proteínas de Membrana Transportadoras , Acinetobacter baumannii/química , Acinetobacter baumannii/enzimologia , Antibacterianos/química , Antibacterianos/metabolismo , Proteínas de Bactérias/química , Proteínas de Bactérias/metabolismo , Clorexidina/química , Clorexidina/metabolismo , RNA Polimerases Dirigidas por DNA/química , RNA Polimerases Dirigidas por DNA/metabolismo , Resistência Microbiana a Medicamentos , Concentração de Íons de Hidrogênio , Espectrometria de Massas , Proteínas de Membrana Transportadoras/química , Proteínas de Membrana Transportadoras/metabolismo , Ligação Proteica , Multimerização Proteica , Subunidades Proteicas/química , Subunidades Proteicas/metabolismo
8.
Food Chem ; 332: 127229, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32688187

RESUMO

Hydrogen peroxide plays a key role in honey antibacterial activity. The production of H2O2 in honey requires glucose oxidase (GOx) that oxidizes glucose to gluconolactone and reduces molecular oxygen to hydrogen peroxide. The content of GOx of honeybee origin was believed to be the main predictor of H2O2 concentration in honey. The observed variations in H2O2 levels among honeys questioned however the direct GOx-H2O2 relationship and left its absence opened for exploration. Here, we evaluated principal causes underlying the imbalance in the quantitative enzyme-product relationship with respect to: (a) enzyme and the product inactivation or destruction by honey compounds; (b) non-enzymatic pathway of H2O2 formation, and (c) a potential contribution of enzymes with GOx activity originating from nectars and microorganisms inhabiting honey. We also bring new facts on the relationship between honey colloidal structure and H2O2 production that change our traditional understanding of honey function as antimicrobial agent.


Assuntos
Mel , Peróxido de Hidrogênio/metabolismo , Antibacterianos/metabolismo , Glucose Oxidase/metabolismo
9.
Int J Nanomedicine ; 15: 4607-4623, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32636621

RESUMO

Aim: The interaction of NPs with biological systems may reveal useful details about their pharmacodynamic, anticancer and antibacterial effects. Methods: Herein, the interaction of as-synthesized Co3O4 NPs with HSA was explored by different kinds of fluorescence and CD spectroscopic methods, as well as molecular docking studies. Also, the anticancer effect of Co3O4 NPs against leukemia K562 cells was investigated by MTT, LDH, caspase, real-time PCR, ROS, cell cycle, and apoptosis assays. Afterwards, the antibacterial effects of Co3O4 NPs against three pathogenic bacteria were disclosed by antibacterial assays. Results: Different characterization methods such as TEM, DLS, zeta potential and XRD studies proved that fabricated Co3O4 NPs by sol-gel method have a diameter of around 50 nm, hydrodynamic radius of 177 nm with a charge distribution of -33.04 mV and a well-defined crystalline phase. Intrinsic, extrinsic, and synchronous fluorescence as well as CD studies, respectively, showed that the HSA undergoes some fluorescence quenching, minor conformational changes, microenvironmental changes as well as no structural changes in the secondary structure, after interaction with Co3O4 NPs. Molecular docking results also verified that the spherical clusters with a dimension of 1.5 nm exhibit the most binding energy with HSA molecules. Anticancer assays demonstrated that Co3O4 NPs can selectively lead to the reduction of K562 cell viability through the cell membrane damage, activation of caspase-9, -8 and -3, elevation of Bax/Bcl-2 mRNA ratio, ROS production, cell cycle arrest, and apoptosis. Finally, antibacterial assays disclosed that Co3O4 NPs can stimulate a promising antibacterial effect against pathogenic bacteria. Conclusion: In general, these observations can provide useful information for the early stages of nanomaterial applications in therapeutic platforms.


Assuntos
Antibacterianos/farmacologia , Antineoplásicos/farmacologia , Cobalto/química , Cobalto/farmacologia , Nanopartículas Metálicas/química , Óxidos/química , Óxidos/farmacologia , Albumina Sérica Humana/metabolismo , Antibacterianos/química , Antibacterianos/metabolismo , Antineoplásicos/química , Antineoplásicos/metabolismo , Apoptose/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Cobalto/metabolismo , Escherichia coli/efeitos dos fármacos , Humanos , Células K562 , Testes de Sensibilidade Microbiana , Simulação de Acoplamento Molecular , Óxidos/metabolismo , Pseudomonas aeruginosa/efeitos dos fármacos , Albumina Sérica Humana/química , Staphylococcus aureus/efeitos dos fármacos , Difração de Raios X
10.
Chemosphere ; 260: 127544, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32673869

RESUMO

Aerobic granular sludge sequencing batch reactor (AGSBR) is a promising approach for wastewater treatment. In the paper, the effects of methanol, starch and sucrose as carbon sources on the treatment of swine wastewater (SW) containing antibiotics by aerobic granular sludge (AGS) were studied. The results revealed that the carbon sources could affect the morphology, biomass, and settleability of AGS, and AGS could maintain a better sludge performance when sucrose was used as carbon source. The pollutants (ammonium nitrogen (NH+ 4-N), organic matter and total phosphorus (TP)) in SW also had a good removal effect, and the removal rates reached 81.14%, 96.83% and 97.37% respectively. The removal efficiencies of tetracycline (TC) and oxytetracycline (OTC) from SW were the best when sucrose as co-metabolic matrix by microorganisms. The analysis of miseq pyrosequencing demonstrated that carbon sources with methanol, starch and sucrose improved the diversity of microbial community in AGS, and the dominant bacteria also changed. The dominant groups involved in TC and OTC, removal at different classification levels suggested that the formation of bacterial communities was determined by carbon sources.


Assuntos
Antibacterianos/metabolismo , Eliminação de Resíduos Líquidos/métodos , Aerobiose , Compostos de Amônio , Animais , Bactérias , Biomassa , Reatores Biológicos , Carbono , Poluentes Ambientais , Microbiota , Nitrogênio , Oxitetraciclina , Fósforo , Esgotos/microbiologia , Suínos , Águas Residuárias
11.
Postepy Biochem ; 66(2): 151-159, 2020 06 27.
Artigo em Polonês | MEDLINE | ID: mdl-32700509

RESUMO

The epithelial tissues have continuous contact with external environment, including pathogenic microorganisms. Endogenous antimicrobial proteins and peptides produced by epithelial cells play a key role in controlling microbial burden and composition, either directly, or by engaging immune cells. These include active derivatives of multifunctional protein chemerin, which is equipped with both antimicrobial and chemotactic function. Given an increasing number of infections caused by antibiotic-insensitive microorganisms, such as methicillin- resistant S. aureus (MRSA), it is important to fully understand how these epithelia-associated microorganisms are controlled at barrier sites, including skin and oral cavity. Chemerin-derived synthetic peptide 4 (p4) covering central Val66-Pro85 chemerin sequence exhibits broad range of antimicrobial activity against skin- and oral cavity- associated bacteria, including MRSA strains, suggesting its therapeutic potential for bacteria-mediated barrier organs pathologies. In this article we present the overview of protective functions of chemerin and chemerin-derived peptides in the epithelial tissues.


Assuntos
Antibacterianos/metabolismo , Bactérias/metabolismo , Quimiocinas/metabolismo , Células Epiteliais/metabolismo , Células Epiteliais/microbiologia , Farmacorresistência Bacteriana , Células Epiteliais/citologia , Humanos , Staphylococcus aureus Resistente à Meticilina/metabolismo
12.
Chemosphere ; 258: 127353, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32554014

RESUMO

Extensive use of antibiotic results in significant antibiotics pollution in the environment. Main objective of this study was to gain insight into potential impacts of antibiotics on plant physiological growth and nutritional composition, and stress alleviation through application of different organic amendments. Effects of five antibiotics (ciprofloxacin, levofloxacin, ofloxacin, amoxicillin and ampicillin) were observed in the presence of three organic amendments (rice husk, farmyard manure and poultry litter) with rice (Oryza sativa L.) as a model plant. Organic amendments were mixed with soil (@ 5 g kg-1) and after three weeks, antibiotics were applied (@10 mg kg-1) and plants were allowed to grow for four months. After which plants were harvested and physical growth parameters (root/shoot length, biomass) and nutritional composition (grain protein content, carbohydrates, phosphorous and iron) were monitored. It was observed that germination rate, seedling root/shoot length, seedling biomass and vigor index were negatively impacted. The application of organic amendments alleviated antibiotic stress on seedling dry biomass, length and vigor index by 1.8-, 3.1- and 2.5-folds, respectively as compared to the antibiotic controls. Concentrations of phosphorous, iron, carbohydrates and proteins were decreased by 5.3-, 1.3-, 1.4- and 1.6-folds upon application of antibiotics. Rice husk was the most effective treatment in case of physical growth parameters and alleviating antibiotics' induced genotoxicity. Whereas, poultry litter had the highest positive effect on nutritional composition of plants. In general, the application of organic amendments alleviated the phytotoxicity as well as genotoxicity in plants under antibiotics stress.


Assuntos
Antibacterianos/toxicidade , Oryza/fisiologia , Poluentes do Solo/toxicidade , Antibacterianos/metabolismo , Biomassa , Poluição Ambiental , Germinação , Esterco , Oryza/metabolismo , Plântula/metabolismo , Solo , Poluentes do Solo/análise
15.
J Med Chem ; 63(10): 5387-5397, 2020 05 28.
Artigo em Inglês | MEDLINE | ID: mdl-32347723

RESUMO

Group A Streptococcus (GAS) infection causes a range of life-threatening diseases, including rheumatic heart disease. Cyclic peptides offer an attractive solution for presentation of short peptide antigens due to their stability and structurally constrained conformation. We investigated a cyclic carrier decapeptide incorporating a B cell GAS peptide epitope, a universal T helper epitope, and a synthetic toll-like receptor 2-targeting moiety as a possible self-adjuvanting GAS vaccine. A structure-activity relationship of the cyclic lipopeptide vaccine showed successful induction of J8-specific systemic immunoglobulin G (IgG) antibodies when administered subcutaneously without an additional adjuvant. Interestingly, the physical mixture control induced the highest titers of all vaccine compounds, with antibodies from mice immunized with this physical mixture control shown to effectively opsonize multiple strains of clinically isolated GAS bacteria. This study showed the capability for a self-adjuvanting cyclic delivery system to act as a vehicle for the delivery of GAS peptide antigens to treat GAS infections.


Assuntos
Antibacterianos/metabolismo , Antígenos de Bactérias/metabolismo , Vacinas Bacterianas/metabolismo , Lipopeptídeos/metabolismo , Infecções Estreptocócicas/metabolismo , Streptococcus pyogenes/metabolismo , Animais , Antibacterianos/administração & dosagem , Antibacterianos/química , Vacinas Bacterianas/administração & dosagem , Vacinas Bacterianas/química , Quimioterapia Adjuvante/métodos , Feminino , Humanos , Lipopeptídeos/administração & dosagem , Lipopeptídeos/química , Camundongos , Camundongos Endogâmicos C57BL , Infecções Estreptocócicas/tratamento farmacológico , Streptococcus pyogenes/efeitos dos fármacos , Relação Estrutura-Atividade
16.
Ecotoxicol Environ Saf ; 196: 110552, 2020 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-32259759

RESUMO

Nowadays, numerous studies have focused on the newly developed technologies for the thorough removal of tetracyclines (TCs). However, it is often ignored that the parent TCs have limited stability in aquatic environments. Thus, this study selected green alga Chlamydomonas reinhardtii with high chlorophyll content to rapidly degrade chlortetracycline (CTC) into products with low toxicity. As the results shown, the half-life times of CTC (1 × 10-6 mol/L) decreased from 10.35 h to 2.55 h by the presence of C. reinhardtii at 24±1 °C with 12/12 h dark/light cycle. The main transformation products were iso-chlortetracycline (ICTC), 4-epi-iso-chlortetracycline (EICTC), and other degradation products with lower molecular weight. The toxicity evaluation shows that the negative effects of CTC on growth rate and soluble protein content of green algae were significantly alleviated after the enhanced degradation treatment, while the generation of reactive oxygen species (ROS) and antioxidant response in algal cells returned to normal levels. The chlorophyll of algae played an important role of photosensitizer, which catalyzed the photo-induced electron/energy transfer of CTC degradation. The ROS generation of algae also was also inseparable from the enhanced degradation of CTC, especially when the chlorophyll was damaged at the high CTC concentration. Based on these results, we can better select suitable algal species to further strengthen the degradation of antibiotics and effectively reduce the environmental risk of CTC in aqueous system.


Assuntos
Antibacterianos/análise , Chlamydomonas reinhardtii/metabolismo , Clortetraciclina/análise , Poluentes Químicos da Água/análise , Antibacterianos/metabolismo , Antibacterianos/toxicidade , Antioxidantes/metabolismo , Biodegradação Ambiental , Chlamydomonas reinhardtii/efeitos dos fármacos , Clorofila/metabolismo , Clorófitas/metabolismo , Clortetraciclina/metabolismo , Clortetraciclina/toxicidade , Inativação Metabólica/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Poluentes Químicos da Água/metabolismo , Poluentes Químicos da Água/toxicidade
17.
Yakugaku Zasshi ; 140(4): 569-576, 2020.
Artigo em Japonês | MEDLINE | ID: mdl-32238639

RESUMO

Daptomycin (DAP) has a completely different mechanism of action compared to conventional methicillin-resistant Staphylococcus aureus (MRSA) drugs and is widely used clinically as the first-line drug for the treatment of skin soft tissue infection and sepsis caused by MRSA infection. However, the most serious side effects of DAP include renal dysfunction and rhabdomyolysis. Knowledge of the time sequence of localization of DAP in cells and tissues of animals may help in developing a better understanding of the actual overall pharmacokinetics of DAP. We prepared DAP-specific antibodies by immunizing mice with DAP-GMBS-BSA conjugate. The Anti-DAP antibody was specific for DAP, which enabled us to develop an immunocytochemical method for detecting the uptake of DAP in the rat kidneys. One hour after a single intravenous (i.v.) injection of DAP at 12 mg/kg, immunohistochemical observation showed a strong ring-like positive reaction in the cytoplasm immediately below the microvilli of proximal tubule epithelial cells. The distal tubules and collecting ducts contained DAP-positive and negative cells in the cross section of one tubule. Twenty-four hours after DAP administration, several strong positive reactions of different sizes were observed in the cytoplasm of epithelial cells at the proximal tubule. No staining was detected after 7 days. This study will be a useful tool for analyzing the pharmacokinetics of DAP.


Assuntos
Antibacterianos/metabolismo , Daptomicina/metabolismo , Imuno-Histoquímica/métodos , Rim/metabolismo , Animais , Antibacterianos/administração & dosagem , Daptomicina/administração & dosagem , Infusões Intravenosas , Masculino , Staphylococcus aureus Resistente à Meticilina , Ratos Wistar , Distribuição Tecidual
18.
Xenobiotica ; 50(10): 1149-1157, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32283993

RESUMO

WCK 771 (INN: levonadifloxacin) is a novel antibacterial agent belonging to benzoquinolizine subclass of fluoroquinolones which is under clinical development as a parenteral formulation and its prodrug WCK 2349 (INN: alalevonadifloxacin) as an oral option. Both the drugs have been approved recently in India based on phase III trial completed for ABSSSI.In vitro CYP inhibition potential of levonadifloxacin and its sulfate metabolite (WCK 2146) were assessed in this study. The inhibitory effects of levonadifloxacin and its sulfate metabolite were assessed for seven key human liver CYP isoforms 1A2, 2B6, 2C8, 2C9, 2C19, 2D6 and 3A4 using human liver microsome (HLM) employing validated LC-MS/MS method.The results showed that levonadifloxacin and its metabolite did not inhibit enzyme activity of any of the key CYP isoforms (1A2, 2B6, 2C8, 2C9, 2C19, 2D6 and 3A4) even at supra therapeutic concentrations (12-24X, Clinical Cmax: 25-35µg/mL).These in vitro CYP inhibition studies of levonadifloxacin and its sulfate metabolite indicate lack of potential for pharmacokinetic drug interactions of levonadifloxacin when co-administered with drugs which are substrate of these isoforms. Therefore, further clinical studies evaluating CYP mediated drug-drug interactions are not warranted for levonadifloxacin and alalevonadifloxacin.


Assuntos
Antibacterianos/farmacologia , Fluoroquinolonas/farmacologia , Alanina , Antibacterianos/metabolismo , Inibidores das Enzimas do Citocromo P-450/farmacologia , Sistema Enzimático do Citocromo P-450/metabolismo , Fluoroquinolonas/metabolismo , Humanos , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Microssomos Hepáticos/metabolismo
19.
Food Chem ; 324: 126867, 2020 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-32344345

RESUMO

The presence of antibiotic residues in the food chain may pose a serious risk to human health. Locating and evaluating new sources of consumer exposure to antibiotic residues in food is a very important element of health protection. The possibility of doxycycline uptake from the substrate for mushroom cultivation by the white button mushroom (Agaricus bisporus) fruit body was investigated. Mushrooms were experimentally cultivated on substrate contaminated with 8 different doxycycline concentrations in substrate and analyte concentrations in mushroom samples were measured using ultra-high performance liquid chromatography - triple quadrupole tandem mass spectrometry (UHPLC-MS/MS) The obtained results clearly indicated that doxycycline transfers from contaminated substrate to mushrooms at concentrations ranging from 0.87 to 72.3 µg/kg, depending on substrate contamination concentration level and order of harvesting.


Assuntos
Agaricus/química , Antibacterianos/metabolismo , Doxiciclina/metabolismo , Agaricus/crescimento & desenvolvimento , Agaricus/metabolismo , Antibacterianos/análise , Cromatografia Líquida de Alta Pressão , Doxiciclina/análise , Humanos , Especificidade por Substrato , Espectrometria de Massas em Tandem
20.
Nucleic Acids Res ; 48(10): 5540-5554, 2020 06 04.
Artigo em Inglês | MEDLINE | ID: mdl-32347931

RESUMO

In the fight against antimicrobial resistance, the bacterial DNA sliding clamp, ß-clamp, is a promising drug target for inhibition of DNA replication and translesion synthesis. The ß-clamp and its eukaryotic homolog, PCNA, share a C-terminal hydrophobic pocket where all the DNA polymerases bind. Here we report that cell penetrating peptides containing the PCNA-interacting motif APIM (APIM-peptides) inhibit bacterial growth at low concentrations in vitro, and in vivo in a bacterial skin infection model in mice. Surface plasmon resonance analysis and computer modeling suggest that APIM bind to the hydrophobic pocket on the ß-clamp, and accordingly, we find that APIM-peptides inhibit bacterial DNA replication. Interestingly, at sub-lethal concentrations, APIM-peptides have anti-mutagenic activities, and this activity is increased after SOS induction. Our results show that although the sequence homology between the ß-clamp and PCNA are modest, the presence of similar polymerase binding pockets in the DNA clamps allows for binding of the eukaryotic binding motif APIM to the bacterial ß-clamp. Importantly, because APIM-peptides display both anti-mutagenic and growth inhibitory properties, they may have clinical potential both in combination with other antibiotics and as single agents.


Assuntos
Antibacterianos/química , Antibacterianos/farmacologia , DNA Polimerase III/antagonistas & inibidores , Peptídeos/química , Peptídeos/farmacologia , Animais , Antibacterianos/metabolismo , Antibacterianos/uso terapêutico , DNA Polimerase III/química , Replicação do DNA/efeitos dos fármacos , DNA Polimerase Dirigida por DNA , Feminino , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Staphylococcus aureus Resistente à Meticilina/genética , Staphylococcus aureus Resistente à Meticilina/crescimento & desenvolvimento , Camundongos Endogâmicos BALB C , Mutagênese/efeitos dos fármacos , Inibidores da Síntese de Ácido Nucleico/química , Inibidores da Síntese de Ácido Nucleico/farmacologia , Inibidores da Síntese de Ácido Nucleico/uso terapêutico , Peptídeos/metabolismo , Peptídeos/uso terapêutico , Antígeno Nuclear de Célula em Proliferação/metabolismo , Domínios e Motivos de Interação entre Proteínas , Infecções Cutâneas Estafilocócicas/tratamento farmacológico , Staphylococcus epidermidis/efeitos dos fármacos , Staphylococcus epidermidis/genética , Staphylococcus epidermidis/crescimento & desenvolvimento
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