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1.
World J Microbiol Biotechnol ; 35(8): 127, 2019 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-31375931

RESUMO

Aeromonas hydrophila is a Gram-negative bacterium that causes serious infections in aquaculture and exhibits significant multidrug resistance. The LysR-type transcriptional regulator (LTTR) family proteins are a well-known group of transcriptional regulators involved in diverse physiological functions. However, the role of LTTRs in the regulation of bacterial resistance to antibiotics is still largely unknown. In this study, to further investigate the role of four putative LTTR family proteins (A0KIU1, A0KJ82, A0KPK0, and A0KQ63) in antibiotic resistance in A. hydrophila, their genes were cloned and overexpressed in engineered Escherichia coli. After the optimization of experimental conditions including incubation time, temperature, and IPTG concentration, these proteins were successfully purified, and their specific antibodies against mice were obtained. Using western blot analysis, we found that these LTTR family proteins were downregulated in A. hydrophila following antibiotic treatment, indicating that they may be involved in the regulation of antibiotic resistance. Additionally, minimum inhibitory concentration (MIC) assays of chloramphenicol (CM), chlortetracycline (CTC), ciprofloxacin (CF), furazolidone (FZ), and balofloxacin (BF) in E. coli showed that overexpression of these LTTRs led to increased sensitivity to several antibiotics. To further validate their functional role in antibiotic resistance, we demonstrated that bacteria with loss of A0KQ63 (ΔAHA_3980) exhibited multi-drug resistance properties. Our results indicate that these LTTR family proteins may play an important role in the antibiotic resistance of A. hydrophila, and the that underlying mechanisms controlling antibiotic resistance should be further investigated.


Assuntos
Aeromonas hydrophila/efeitos dos fármacos , Aeromonas hydrophila/genética , Farmacorresistência Bacteriana , Regulação Bacteriana da Expressão Gênica , Genes Reguladores , Fatores de Transcrição/metabolismo , Animais , Antibacterianos/farmacologia , Proteínas de Bactérias/genética , Western Blotting , Clonagem Molecular , Escherichia coli/efeitos dos fármacos , Escherichia coli/genética , Escherichia coli/metabolismo , Deleção de Genes , Expressão Gênica , Perfilação da Expressão Gênica , Genes Bacterianos , Camundongos , Testes de Sensibilidade Microbiana , Fatores de Transcrição/análise , Fatores de Transcrição/genética
2.
Pestic Biochem Physiol ; 158: 185-200, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31378356

RESUMO

The present work describes the antimicrobial action of 25 monoterpenes (six hydrocarbons, five ketones, two aldehydes, six alcohols and six acetate analogues) against Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus and antifungal activity against Aspergillus flavus. The antibacterial activity was evaluated by broth microdilution technique as a minimum inhibitory concentration (MIC) and the antifungal activity was performed by mycelia radial growth technique as the effective concentration causing 50% inhibition of the mycelial growth (EC50). The results showed that thymol and α-terpineol were the most potent against E. coli (MIC = 45 and 55 mg/L, respectively) and S. aureus (MIC = 135 and 225 mg/L, respectively). The results also showed that thymol displayed the maximum antifungal action against A. flavus with EC50 20 mg/L. Furthermore, the antioxidant activity was determined using N,N-dimethyl-1,4-phenylenediamine (DMPD) and the results showed that geraniol were the most potent compound (IC50 = 19 mg/L). Molecular docking studies indicated that the compounds displayed different binding interactions with the amino acid residues at the catalytic sites of N5-carboxyaminoimidazole synthetase and oxysterol binding protein Osh4 enzymes. Non-covalent interactions including van der Waals, hydrogen bonding as well as hydrophobic were observed between the compounds and the enzymes. A significant relationship was found between the docking score and the biological activity of the tested monoterpenes compared to the ceftriaxone and carbendazim as standard bactericide and fungicide, respectively. In silico ADMET properties were also performed and displayed potential for the development of promising antimicrobial agents. For these reasons, these compounds may be considered as potential ecofriendly alternatives in food preservation to delay or prevent the microbial infection and prolong the shelf life of food products.


Assuntos
Anti-Infecciosos/farmacologia , Antioxidantes/farmacologia , Monoterpenos/metabolismo , Antibacterianos/química , Antibacterianos/farmacologia , Anti-Infecciosos/química , Cicloexenos/química , Cicloexenos/farmacologia , Escherichia coli/efeitos dos fármacos , Hidrocarbonetos/química , Hidrocarbonetos/farmacologia , Testes de Sensibilidade Microbiana , Monoterpenos/química , Monoterpenos/farmacologia , Staphylococcus aureus/efeitos dos fármacos
3.
Shokuhin Eiseigaku Zasshi ; 60(3): 45-51, 2019.
Artigo em Japonês | MEDLINE | ID: mdl-31391410

RESUMO

This study aimed to survey the trend of antimicrobial resistance in Escherichia coli obtained from retail meat. We examined the susceptibilities of 1,115 E. coli isolates obtained from chicken, beef, pork, venison, and wild boar meat from 2011 to 2017 in Tokyo to 14 antimicrobials (ampicillin, cefotaxime (CTX), streptomycin, gentamicin, kanamycin, tetracycline (TC), chloramphenicol, nalidixic acid, ciprofloxacin, sulfamethoxazole-trimethoprim, fosfomycin, amikacin, imipenem, and meropenem). Of all the tested isolates, 18.7% (135/721) isolates from chicken, 77.0% (117/152) from beef, 46.6% (89/187) from pork, 100% (28/28) from venison, and 92.6% (25/27) from wild boar meat were susceptible to all tested antimicrobials. Furthermore, TC resistance was the most common, with rates as high as 56.7% (409/721) and 40.6% (76/187) in the isolates from chicken and pork, respectively. CTX resistance was detected in 4.9% (25/506) of the isolates from domestic chicken and 23.7% (51/215) of the isolates from imported chicken. Moreover, CTX resistance rate in isolates from domestic chicken was significantly lower in 2016 (0.9%, 1/111) and in 2017 (0.8%, 1/121) than in 2012 (10.6%, 17/161). In conclusion, E. coli isolates from retail meat were most commonly resistant to TC, and CTX resistance was higher in E. coli isolates from imported chicken than in E. coli isolates from domestic chicken.


Assuntos
Antibacterianos/farmacologia , Farmacorresistência Bacteriana , Escherichia coli/efeitos dos fármacos , Microbiologia de Alimentos , Carne/microbiologia , Animais , Bovinos , Galinhas , Cervos , Testes de Sensibilidade Microbiana , Prevalência , Suínos , Tóquio
4.
J Microbiol ; 57(9): 781-794, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31452043

RESUMO

The phytopathogenic Burkholderia species B. glumae and B. plantarii are the causal agents of bacterial wilt, grain rot, and seedling blight, which threaten the rice industry globally. Toxoflavin and tropolone are produced by these phytopathogens and are considered the most hostile biohazards with a broad spectrum of target organisms. However, despite their nonspecific toxicity, the effects of toxoflavin and tropolone on bacteria remain unknown. RNA-seq based transcriptome analysis was employed to determine the genome-wide expression patterns under phytotoxin treatment. Expression of 2327 and 830 genes was differentially changed by toxoflavin and tropolone, respectively. Enriched biological pathways reflected the down-regulation of oxidative phosphorylation and ribosome function, beginning with the inhibition of membrane biosynthesis and nitrogen metabolism under oxidative stress or iron starvation. Conversely, several systems such as bacterial chemotaxis, flagellar assembly, biofilm formation, and sulfur/taurine transporters were highly expressed as countermeasures against the phytotoxins. In addition, our findings revealed that three hub genes commonly induced by both phytotoxins function as the siderophore enterobactin, an iron-chelator. Our study provides new insights into the effects of phytotoxins on bacteria for better understanding of the interactions between phytopathogens and other microorganisms. These data will also be applied as a valuable source in subsequent applications against phytotoxins, the major virulence factor.


Assuntos
Antibacterianos/toxicidade , Burkholderia/química , Proteínas de Escherichia coli/genética , Escherichia coli/efeitos dos fármacos , Doenças das Plantas/microbiologia , Pirimidinonas/toxicidade , Triazinas/toxicidade , Tropolona/toxicidade , Antibacterianos/metabolismo , Burkholderia/metabolismo , Escherichia coli/genética , Escherichia coli/crescimento & desenvolvimento , Escherichia coli/metabolismo , Proteínas de Escherichia coli/metabolismo , Perfilação da Expressão Gênica , Regulação Bacteriana da Expressão Gênica/efeitos dos fármacos , Oryza/microbiologia , Pirimidinonas/metabolismo , Transcriptoma/efeitos dos fármacos , Triazinas/metabolismo , Tropolona/metabolismo
5.
Dokl Biochem Biophys ; 486(1): 206-208, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-31367822

RESUMO

The aim of this work was to study the fine structure of bacterial films grown on the inner tube surface of a flow reactor. Using the scanning electron microscopy (SEM) approaches, the detailed biofilm relief was visualized. The action of electrochemically reduced water (ERW) on the biofilm ultrastructure generated by the plankton form of E. coli and/or lacto bacteria was investigated. The treatment with an ERW solution destroyed the biofilm organic polymer matrix and bacterial cells embedded in the matrix.


Assuntos
Biofilmes/efeitos dos fármacos , Água/química , Água/farmacologia , Biofilmes/crescimento & desenvolvimento , Eletroquímica , Escherichia coli/efeitos dos fármacos , Escherichia coli/fisiologia
6.
BMC Vet Res ; 15(1): 268, 2019 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-31357996

RESUMO

BACKGROUND: This study investigated changes over time in the epidemiology of extended-spectrum ß-lactamase (ESBL) producing Escherichia coli within a single equine referral hospital in the UK. Faecal samples were collected from hospitalised horses in 2008 and 2017, processed using selective media and standard susceptibility laboratory methods. A novel real-time PCR with high resolution melt analysis was used to distinguish blaCTX-M-1 and blaCTX-M-15 within CTX-M-1 group. RESULTS: In 2008, 457 faecal samples from 103 horses were collected, with ESBL-producing E. coli identified in 131 samples (28.7, 95% CI 24.6-33.1). In 2017, 314 faecal samples were collected from 74 horses with ESBL-producing E. coli identified in 157 samples (50.0, 95% CI 44.5-55.5). There were 135 and 187 non-duplicate ESBL-producing isolates from 2008 and 2017, respectively. In 2008, 12.6% of isolates belonged to CTX-M-1 group, all carrying blaCTX-M-1, whilst in 2017, 94.1% of isolates were CTX-M-1 group positive and of these 39.2 and 60.8% of isolates carried blaCTX-M-1 and blaCTX-M-15, respectively. In addition, the prevalence of doxycycline, gentamicin and 3rd generation cephalosporin resistance increased significantly from 2008 to 2017 while a decreased prevalence of phenotypic resistance to potentiated sulphonamides was observed. CONCLUSIONS: The real-time PCR proved a reliable and high throughput method to distinguish between blaCTX-M-1 and blaCTX-M-15. Furthermore, its use in this study demonstrated the emergence of faecal carriage of CTX-M-15 in hospitalised horses, with an increase in prevalence of ESBL-producing E. coli as well as increased antimicrobial resistance to frequently used antimicrobials.


Assuntos
Infecções por Escherichia coli/veterinária , Fezes/microbiologia , Doenças dos Cavalos/epidemiologia , Doenças dos Cavalos/microbiologia , beta-Lactamases/metabolismo , Animais , Antibacterianos/farmacologia , Farmacorresistência Bacteriana , Escherichia coli/efeitos dos fármacos , Escherichia coli/enzimologia , Escherichia coli/genética , Infecções por Escherichia coli/epidemiologia , Infecções por Escherichia coli/microbiologia , Cavalos , Hospitais Veterinários/estatística & dados numéricos , Prevalência , Reino Unido/epidemiologia , beta-Lactamases/genética
7.
Gene ; 713: 143951, 2019 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-31269464

RESUMO

Rifampicin (RIF) is still a first line of antibiotic in the treatment of bacterial diseases, in particular the Mycobacterial infections. The antimicrobial activity of RIF is attributed to its ability to inhibit transcription by binding to the ß subunit of bacterial RNA polymerase (encoded by rpoB). Continued use of this drug resulted in the emergence of RIF resistant rpoB mutations in a high frequency that compels the use of RIF almost exclusively in drug combinations. As of date, a broad array of rif mutations have been isolated and characterized by different research groups. Studies on rpoB mutations strengthen the view that the ß subunit of RNA polymerase (RNAP) is very crucial in modulating transcription thereby leading to differential gene expression. Very recently we have reported the transcriptome profile of rpoB12 mutant that provides molecular evidence that presence of rpoB12 mutation modulates the transcription of about 450 genes. Here we present a maiden report that rpoB mutations that substitute Tyr at the Rif binding pocket (RBP) of ß subunit of RNA polymerase are able to suppress the over-production of colanic acid capsular polysaccharide (Ces phenotype) in Δlon mutant of Escherichia coli. Further analyses of the rif mutants involving their growth pattern on LB at higher temperature (42 °C), LB media without NaCl, survival in LB media with acidic pH (pH - 3) and motility revealed that only rpoB12 (His526Tyr) and rpoB137 (Ser522Tyr) affected all the above mentioned physiological parameters in addition to the elicitation of Ces phenotype. These two rif mutations confer fast movement to RNAP and they bear Tyr as the substituted amino acid in the RBP. This is perhaps the first study that brings out the possible role of Tyr in the RBP and its participation in the global gene expression. This study also envisages the point that amino acid residues that share the properties of Tyr in the RBP can be employed as a tool to bring out differential gene expression which would certainly have basic and applied values for the mankind.


Assuntos
RNA Polimerases Dirigidas por DNA/genética , RNA Polimerases Dirigidas por DNA/metabolismo , Proteínas de Escherichia coli/genética , Escherichia coli/metabolismo , Mutação , Rifampina/farmacologia , Tirosina/metabolismo , Antibióticos Antituberculose/farmacologia , Farmacorresistência Bacteriana , Escherichia coli/efeitos dos fármacos , Escherichia coli/genética , Proteínas de Escherichia coli/metabolismo , Regulação Bacteriana da Expressão Gênica , Fenótipo , RNA Bacteriano , Tirosina/genética
8.
J Photochem Photobiol B ; 197: 111539, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31301638

RESUMO

Treatment of burn injury is clinically challenging one, therefore several steps and noteworthy approaches have been taken to improve wound mechanisms. Citrus pectin plays a stabilizing agent to synthesis of ZnO nanoparticles (ZnO NPs). The present study is focused on ZnO loaded collagen/chitosan nanofibrous were synthesized by electrospinning method using ZnO NPs. The chemical structure, phase purity and morphological observation were investigated under spectroscopic and mircoscopic techniques and demonstrated their suitable properties as a wound healing material. In addition, that prepared nanoparticles loaded biopolymeric fibrous nanomaterial showed suitable antibacterial activity against S. aureus and E. coli bacterial pathogens and also in vitro studies was confirmed the enhanced proliferation, cell viability and biocompatibility. In vitro evaluations have been exhibited acceptable cell proliferation is observed throughout the ZnO loaded Coll/CS nanofibrous within 3 days, which was comparable to the control material. In vivo wound healing ability was monitored on the rat wound experimental model. From the in vivo observations, revealed that the loaded of ZnO NPs with Coll/CS nanofibrous can effectively quicken wound healing mechanism, expressed in the initial stage healing process. These results suggest that ZnO loaded collagen/chitosan nanofibrous is a potential candidate for wound healing applications with enhanced biological properties.


Assuntos
Queimaduras/patologia , Quitosana/química , Colágeno/química , Nanopartículas Metálicas/química , Nanofibras/química , Animais , Antibacterianos/química , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Bacteriemia/prevenção & controle , Queimaduras/veterinária , Linhagem Celular , Proliferação de Células/efeitos dos fármacos , Escherichia coli/efeitos dos fármacos , Fibroblastos/citologia , Fibroblastos/efeitos dos fármacos , Fibroblastos/metabolismo , Humanos , Nanofibras/uso terapêutico , Nanofibras/toxicidade , Ratos , Pele/efeitos dos fármacos , Pele/patologia , Staphylococcus aureus/efeitos dos fármacos , Cicatrização/efeitos dos fármacos , Óxido de Zinco/química
9.
Talanta ; 202: 384-391, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31171199

RESUMO

A novel microfluidic paper-based analytical device (µPAD) was developed with benzoquinone (BQ)-mediated E. coli respiration method to measure the biotoxicities of pollutants. Functional units including sample injection, fluid-cell separation, all-carbon electrode-enabled electrochemical detection, were integrated on a piece of chromatography paper. The three-electrode, working electrode, counter electrode and reference electrode, were simultaneously screen-printed on the µPAD with conductive carbon ink. The satisfying electrochemical performance of the paper-based carbon three-electrode was confirmed by cyclic voltammetry detecting K3 [Fe(CN)6]. The process of cell toxication was considered that toxicants inhibited cell respiration and diminished the electrons on E. coli respiratory chain. It was quantitatively reflected by measuring oxidation current of hydroquinone (HQ) as a reduced state of the redox mediator BQ after the incubation of cells with pollutants. The current detection time, BQ concentration and E. coli incubation time were carefully optimized to establish the systematic optimized operations of BQ-mediated E. coli respiration method. Using the fabricated µPAD the half inhibitory concentration (IC50) were Cu2+ solution 13.5 µg mL-1, Cu2+-soil 21.4 mg kg-1, penicillin sodium-soil 85.1 mg kg-1, and IC30 of Pb2+ solution was 60.0 µg mL-1. Detection of pesticide residues in vegetable juices were accomplished in a similar way. The proposed method is fascinating on three points; 1) The generality in the biotoxicity detection depends on toxicants inducing cellular respiratory inhibition; 2) The portability and affordability make it convenient for practical applications, because of replacing incubators and centrifuges; 3) There is potential applicability in less-developed areas due to its simple operation and low-cost.


Assuntos
Técnicas Eletroquímicas , Poluentes Ambientais/farmacologia , Escherichia coli/efeitos dos fármacos , Técnicas Analíticas Microfluídicas , Papel , Benzoquinonas/química , Eletrodos , Poluentes Ambientais/análise , Escherichia coli/citologia , Escherichia coli/metabolismo
10.
Pharm Res ; 36(8): 122, 2019 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-31218556

RESUMO

PURPOSE: A non-propellant based foam (NPF) system was developed incorporating the antibiotics, pectin capped green nano-silver and sulfadiazine (SD) for the topical treatment of burn wounds as a convenient alternative to the existing therapies. METHODS: NPF were prepared using various surfactants and oils forming a nanoemulsion. Anti-microbial studies by resazurin microtitre assay, ex vivo diffusion, in vivo skin permeation and deposition studies, and acute irritation studies were carried out. NPF was applied onto secondary thermal wounds manifested on mice models followed by macroscopic and histological examinations. RESULTS: NPF had an average globule size of <75 nm. The viscosity was ~10 cP indicating the feasibility of expulsion from the container upon actuation. With no skin irritation, the foams showed a higher skin deposition of SD. A high contraction and an evident regeneration of the skin tissue upon treatment with NPF indicated a good recovery from the thermal injury was apparent from the histology studies. CONCLUSION: NPF represents an alternative topical formulation that can be employed as a safe and effective treatment modality for superficial second degree (partial thickness) burn wounds. With a minimal requirement of mechanical force, the no-touch application of NPF makes it suitable for sensitive and irritant skin surfaces.


Assuntos
Antibacterianos/farmacologia , Queimaduras/tratamento farmacológico , Nanopartículas Metálicas/química , Prata/química , Sulfadiazina/farmacologia , Cicatrização/efeitos dos fármacos , Administração Tópica , Animais , Antibacterianos/administração & dosagem , Queimaduras/patologia , Queimaduras/fisiopatologia , Composição de Medicamentos/métodos , Quimioterapia Combinada , Emulsões , Escherichia coli/efeitos dos fármacos , Química Verde , Humanos , Masculino , Camundongos , Óleos/química , Tamanho da Partícula , Permeabilidade , Pele/efeitos dos fármacos , Pele/patologia , Pele/fisiopatologia , Staphylococcus aureus/efeitos dos fármacos , Sulfadiazina/administração & dosagem , Tensoativos/química
11.
Life Sci ; 230: 178-187, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-31152810

RESUMO

AIMS: With the purpose of exploring combinatorial options that could enhance the bactericide efficacy of linezolid against Gram-negative bacteria, we assessed the extent of combination of nano-silver and linezolid. MAIN METHODS: In this study, we selected Escherichia coli MTCC 443 as a model to study the combinatorial effect of nano-silver and linezolid to combat efflux-mediated resistance in Gram-negative bacteria. The acting mechanism of nano-silver on E. coli MTCC 443 was investigated by evaluating interaction of nano-silver with bacterial membrane as well as bacterial surface charge, morphology, intracellular leakages and biological activities of membrane bound respiratory chain dehydrogenase and deoxyribonucleic acids (DNA) of the cells following treatment with nano-silver. KEY FINDINGS: The alternation of zeta potential due to the interaction of nano-silver towards bacterial membrane proteins was correlated with enhancement of membrane permeability, which allows the penetration of linezolid into the cells. In addition, the binding affinity of nano-silver towards bacterial membrane depressed biological activities of membrane bound respiratory chain dehydrogenases and DNA integrity. SIGNIFICANCE: Our findings suggested that nano-silver could not only obstruct the activities of efflux pumps, but also altered membrane integrity at the same time and thus increased the cytoplasmic concentration of the linezolid to the effective level.


Assuntos
Proteínas da Membrana Bacteriana Externa/efeitos dos fármacos , Nanopartículas Metálicas/uso terapêutico , Prata/farmacologia , Antibacterianos/farmacologia , Proteínas de Bactérias/efeitos dos fármacos , Permeabilidade da Membrana Celular/efeitos dos fármacos , Farmacorresistência Bacteriana/efeitos dos fármacos , Farmacorresistência Bacteriana Múltipla , Escherichia coli/efeitos dos fármacos , Escherichia coli/metabolismo , Bactérias Gram-Negativas/metabolismo , Linezolida/metabolismo , Linezolida/farmacologia , Prata/metabolismo
12.
Chem Commun (Camb) ; 55(49): 7001-7004, 2019 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-31155630

RESUMO

Chiral polyoxometalates (POMs) were deposited onto the inner surface of an ordered cavernous film to construct POM-based chiral interfaces, which exhibit a significantly different chiral influence on the adhesion and proliferation of Escherichia coli (E. coli) cells tuned by protein adsorption. Anti-fouling was also shown for the racemic surface.


Assuntos
Aderência Bacteriana/efeitos dos fármacos , Escherichia coli/citologia , Escherichia coli/efeitos dos fármacos , Compostos de Tungstênio/farmacologia , Adesão Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Imagem Óptica , Propriedades de Superfície
13.
Pestic Biochem Physiol ; 157: 108-121, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31153458

RESUMO

Karanjin, a furanoflavonol from Pongamia pinnata L is used in agricultural practices for its pesticidal, insecticidal and acaricidal activities. It is commercially available as a bio-pesticide targeting a wide variety of pests. The present study was intended to evaluate the biochemical interactions of karanjin with bovine serum albumin (BSA) and study its toxicological effects on mammalian and bacterial cell lines. Karanjin bound to BSA at a single site with a dissociation constant of 19.7 µM. Evaluation of BSA-karanjin interactions at three different temperatures indicated the involvement of static mode of quenching. Binding experiments in the presence of warfarin and computational docking analysis indicated that karanjin bound closer to the warfarin binding site located in the Subdomain IIA of BSA. Using Förster resonance energy transfer analysis the distance between TRP 213 of BSA and karanjin was found to be 20 Å. Collective results from synchronous fluorescence spectra analysis, differential scanning calorimetry, and circular dichroism analysis indicated that binding of karanjin induced conformational changes in the secondary structure of BSA. Karanjin exhibited low toxicity against human cervical cancer cells and normal mouse fibroblast L929 cells and modestly inhibited the growth of B. subtilis and E. coli cells. The data presented in this study provides insights for understanding the binding interactions of karanjin with BSA and its possible toxicological effects on mammalian cell lines and bacteria.


Assuntos
Benzopiranos/metabolismo , Benzopiranos/toxicidade , Óleos Vegetais/química , Óleos Vegetais/toxicidade , Pongamia/química , Sementes/química , Animais , Sítios de Ligação , Agentes de Controle Biológico/química , Agentes de Controle Biológico/toxicidade , Bovinos , Linhagem Celular , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Escherichia coli/efeitos dos fármacos , Transferência Ressonante de Energia de Fluorescência , Humanos , Camundongos , Ligação Proteica , Soroalbumina Bovina/metabolismo
14.
Chemotherapy ; 64(1): 22-27, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31167192

RESUMO

BACKGROUND: Pantothenate, the fundamental precursor to coenzyme A, is required for optimal growth and virulence of microbial pathogens. It is synthesized by the enzyme-catalyzed condensation of ß-alanine and pantoate, which has shown susceptibility to inhibition by analogs of its molecular constituents. Accordingly, analogs of ß-alanine are gaining inquiry as potential antimicrobial chemotherapeutics. METHODS: We synthesized and evaluated 35 derivatives of ß-alanine, substituted at the α, ß, amine, and carboxyl sites, derived from in silico, dynamic molecular modeling to be potential competitive inhibitors of pantothenate synthetase. Employing the Clinical Laboratory Standards M7-A6 broth microdilution method, we tested these for inhibition of growth in Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa. RESULTS: All compounds proved entirely ineffective in all species tested, with no inhibition of growth being observed up to 200 µM/mL. CONCLUSIONS: Upon revision of the literature, we conclude that high enzyme selectivity or external salvage mechanisms may render this strategy futile against most bacteria.


Assuntos
Proteínas de Bactérias/metabolismo , Peptídeo Sintases/metabolismo , beta-Alanina/metabolismo , Proteínas de Bactérias/antagonistas & inibidores , Sítios de Ligação , Escherichia coli/efeitos dos fármacos , Escherichia coli/enzimologia , Escherichia coli/crescimento & desenvolvimento , Simulação de Acoplamento Molecular , Peptídeo Sintases/antagonistas & inibidores , Estrutura Terciária de Proteína , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/crescimento & desenvolvimento , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/crescimento & desenvolvimento , beta-Alanina/análogos & derivados , beta-Alanina/farmacologia
15.
Future Microbiol ; 14: 691-704, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-31148474

RESUMO

Aim: To determine the prevalence of New Delhi metallo-ß-lactamase (NDM)-producing Gram-negative pathogens isolated from children's samples. Materials & methods: Carbapenem-resistant clinical isolates (n = 117) were confirmed by VITEK® 2 compact system, matrix-assisted laser desorption ionization-time of flight and multilocus sequence typing. MIC (µg/ml) of various antibiotics was determined by VITEK 2 compact system. Molecular characterization of the isolates was performed by PCR, DNA sequencing, PFGE and DNA hybridization. Results: Out of 117 carbapenemase producers, 37 (31.6%) and 29 (24.7%) were Klebsiella pneumoniae and Acinetobacter baumannii, respectively. 72 (61.5%) isolates were NDM positive and among these 60, 9 and 3 were NDM-1, -5 and -7, respectively. Majority of the NDM-producing K. pneumoniae belonged to ST11 and ST273 while most of the Escherichia coli belonged to ST405 and ST101. blaNDM were mainly located on 150kb plasmids. MIC displayed high resistance against ß-lactams drugs including carbapenems, and the most sensitive drugs were tigecycline and colistin. Conclusion: Dissemination of blaNDM-producing pathogens, particularly in children clinical settings, is a matter of great public health concern.


Assuntos
Bactérias Gram-Negativas/enzimologia , Bactérias Gram-Negativas/genética , beta-Lactamases/biossíntese , beta-Lactamases/genética , Acinetobacter baumannii/efeitos dos fármacos , Acinetobacter baumannii/enzimologia , Acinetobacter baumannii/genética , Acinetobacter baumannii/isolamento & purificação , Antibacterianos/farmacologia , Proteínas de Bactérias/biossíntese , Proteínas de Bactérias/genética , Criança , DNA Bacteriano/análise , Farmacorresistência Bacteriana Múltipla/genética , Escherichia coli/efeitos dos fármacos , Escherichia coli/enzimologia , Escherichia coli/genética , Escherichia coli/isolamento & purificação , Feminino , Perfilação da Expressão Gênica , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Negativas/isolamento & purificação , Infecções por Bactérias Gram-Negativas/epidemiologia , Infecções por Bactérias Gram-Negativas/microbiologia , Humanos , Klebsiella pneumoniae/efeitos dos fármacos , Klebsiella pneumoniae/enzimologia , Klebsiella pneumoniae/genética , Klebsiella pneumoniae/isolamento & purificação , Masculino , Testes de Sensibilidade Microbiana , Epidemiologia Molecular , Tipagem de Sequências Multilocus , Paquistão/epidemiologia , Plasmídeos , Análise de Sequência de DNA
16.
Environ Pollut ; 249: 1106-1114, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31146316

RESUMO

Graphene oxide (GO) has been demonstrated to be key component for diverse applications. However, their potential environmental reactivity, fate and risk have not been fully evaluated to date. In this study, we investigated the photochemical reactivity of four types of GO with different oxidation degrees in aqueous environment, and their related toxicity to two bacterial models Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) was further compared. After UV-irradiation, a large amount of oxygen functional groups on GO were reduced and the electronic conjugations within GO were restored as indicated by UV-visible absorption spectra, X-ray photoelectron spectroscopy and Raman spectroscopy analysis. Moreover, the higher the oxidation degree of the pristine GO was, the more obvious of the photo-transformation changes were. In order to further reveal the photochemical reactivity mechanisms, the reactive oxygen species (ROS) generation of GO was monitored. The quantity of ROS including singlet oxygen (1O2), superoxide anions (O2·-), and hydroxyl radicals (·OH) increased with increasing oxidation degree of GO, which was in accordance with the previous characterization results. Scanning electron microscopy and cell growth analyses of E. coli and S. aureus showed that the photochemical transformation enhanced the toxicity of GO, which might be due to an increase in functional group density. The higher conductivity of the reduced graphene oxide (RGO) was responsible for its stronger toxicity than GO through membrane damage and oxidative stress to bacteria. This study revealed that the oxidation degrees play important roles in photochemical transformation and the resulting toxicity of GO, which is helpful for understanding the environmental behaviors and risks of GO in aquatic environments.


Assuntos
Escherichia coli/efeitos dos fármacos , Grafite/toxicidade , Estresse Oxidativo/efeitos dos fármacos , Staphylococcus aureus/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Escherichia coli/crescimento & desenvolvimento , Grafite/efeitos da radiação , Oxirredução , Processos Fotoquímicos , Espécies Reativas de Oxigênio/metabolismo , Staphylococcus aureus/crescimento & desenvolvimento , Poluentes Químicos da Água/efeitos da radiação
17.
Int J Nanomedicine ; 14: 3245-3263, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31190792

RESUMO

Background: Bacterial resistance to antibiotics is one of the biggest challenges facing medicine today. Anti-adhesive therapy, using inhibitors of bacterial adhesion to epithelial cells, one of the first stages of infection, is a promising approximation in this area. The size, shape, number of sugar and their placement are variables that have to be taken into account in order to develop multivalent systems able to inhibit the bacterial adhesion based on sugar-lectin interaction. Materials and methods: In the present work we report a modular approach for the synthesis of water-soluble 1D-carbon nanotube-sugar nanoconstructs, with the necessary flexibility to allow an efficient sugar-lectin interaction. The method is based on the reaction of aryl diazonium salts generated in situ from aniline-substituted mannose and lactose derivatives with single wall carbon nanotubes (SWCNTs) sidewalls. Results: Two hybrid nanosystems, I-II, exposing mannose or lactose and having a tetraethylene glycol spacer between the sugar and the nanotube sidewall were rapidly assembled and adequately characterized. The sweet nano-objects were then tested for their ability to agglutinate and selectively inhibit the growth of uropathogenic Escherichia coli. These studies have shown that nanosystem I, exposing mannose on the nanotube surface is able to agglutinate and to inhibit the bacterial growth unlike nano-objects II exposing lactose. Conclusion: The results reported constitute a proof of principle in using mannose-coated 1D-carbon nanotubes as antiadhesive drugs that compete for FimH binding and prevent the uropathogenic bacteria from adhering to the urothelial surface.


Assuntos
Escherichia coli/citologia , Nanotubos de Carbono/química , Aglutinação , Aderência Bacteriana/efeitos dos fármacos , Escherichia coli/efeitos dos fármacos , Escherichia coli/ultraestrutura , Manose/química , Nanotubos de Carbono/ultraestrutura , Polissacarídeos/síntese química , Polissacarídeos/química , Propriedades de Superfície
18.
Int J Nanomedicine ; 14: 3345-3360, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31190796

RESUMO

Background: Designing a wound dressing that effectively prevents multi-drug-resistant bacterial infection and promotes angiogenesis and re-epithelialization is of great significance for wound management. Methods and results: In this study, a biocompatible composite membrane comprising biomimetic polydopamine-modified eggshell membrane nano/microfibres coated with KR-12 antimicrobial peptide and hyaluronic acid (HA) was developed in an eco-friendly manner. The physicochemical properties of the composite membrane were thoroughly characterized, and the results showed that the surface hydrophilicity and water absorption ability of the composite membrane were improved after the successive conjugation of the HA and the KR-12 peptide. Furthermore, the in vitrobiological results revealed that the composite membrane had excellent antibacterial activity against Gram-positive Staphylococcus aureus, methicillin-resistant Staphylococcus aureus (MRSA) and Gram-negative Escherichia coli, and it could prevent MRSA biofilm formation on its surface. Additionally, it promoted the proliferation of keratinocytes and human umbilical vein endothelial cells and increased the secretion of VEGF. Finally, an in vivo animal study indicated that the composite membrane could promote wound healing via accelerating angiogenesis and re-epithelialization, which were demonstrated by the enhanced expression of angiogenetic markers (CD31 and VEGF) and keratinocyte proliferation marker (PCNA), respectively. Conclusion: These results indicated that the composite membrane is a potential candidate of wound dressings.


Assuntos
Farmacorresistência Bacteriana Múltipla/efeitos dos fármacos , Casca de Ovo/química , Ácido Hialurônico/farmacologia , Neovascularização Fisiológica/efeitos dos fármacos , Peptídeos/farmacologia , Reepitelização/efeitos dos fármacos , Animais , Antibacterianos/farmacologia , Galinhas , Escherichia coli/efeitos dos fármacos , Células Endoteliais da Veia Umbilical Humana/citologia , Células Endoteliais da Veia Umbilical Humana/efeitos dos fármacos , Humanos , Queratinócitos/citologia , Queratinócitos/efeitos dos fármacos , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Camundongos , Testes de Sensibilidade Microbiana , Peptídeos/química , Porosidade , Staphylococcus aureus/efeitos dos fármacos
19.
Int J Nanomedicine ; 14: 3533-3541, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31190810

RESUMO

Background: Himalayan honey, a natural product of wild honey bees found in the Himalayan mountains of Nepal, has been used in medicine for many years. The successful development of nanotechnology and beneficial effects of honey would bring a new opportunity to synthesize hybrid nanomaterials for biomedical applications. Thus, the purpose of this study was to load Himalayan honey onto iron oxide nanoparticles (IO-NPs) and study their antioxidant and antimicrobial activities. Methods: Himalayan honey loaded iron oxide nanoparticles (HHLIO-NPs) were synthesized and X-ray diffraction (XRD) and scanning electron microscope (SEM) analyses were performed for characterization. UV-VIS spectra confirmed the loading of honey onto nanoparticles. The antioxidant activity of these nanoparticles was studied against 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical system. We also tested antimicrobial activity of HHLIO-NPs using well diffusion method towards both Gram-positive and Gram-negative bacterial strains of Staphylococus aureus & Escherichia coli. Results: From XRD analysis, the average particle size was found to be 33-40 nm. The SEM images show needle shape porous structures of HHLIO-NPs compared to free IO-NPs indicating the surfactant-like behaviour of honey. In DPPH radical system, the scavenging activities of Himalayan honey (HH), free IO-NPs and HHLIO-NPs ranged 7.93-35.99%, 11.02-52.02% and 16.10-80.52% respectively, with corresponding IC50 values of 1.36 mg/mL, 1.09 mg/mL and 0.52 mg/mL. The antimicrobial property of all test samples showed a noteworthy inhibition on both bacterial strains. However, the HH and HHLIO-NPs exhibited strong antibacterial activity against E. coli. Conclusion: This work reveals that the biological activity of HH is enhanced significantly after loading into IO-NPs. Thus, the HHLIO-NPs would be a promising alternative for antioxidant and antimicrobial agents.


Assuntos
Anti-Infecciosos/farmacologia , Antioxidantes/farmacologia , Compostos Férricos/química , Mel , Nanopartículas Metálicas/química , Antibacterianos/farmacologia , Escherichia coli/efeitos dos fármacos , Concentração Inibidora 50 , Nanopartículas Metálicas/ultraestrutura , Testes de Sensibilidade Microbiana , Tamanho da Partícula , Espectrofotometria Ultravioleta , Staphylococcus aureus/efeitos dos fármacos , Difração de Raios X
20.
Nat Commun ; 10(1): 2635, 2019 06 14.
Artigo em Inglês | MEDLINE | ID: mdl-31201302

RESUMO

Multidrug efflux pumps actively expel a wide range of toxic substrates from the cell and play a major role in intrinsic and acquired drug resistance. In Gram-negative bacteria, these pumps form tripartite assemblies that span the cell envelope. However, the in situ structure and assembly mechanism of multidrug efflux pumps remain unknown. Here we report the in situ structure of the Escherichia coli AcrAB-TolC multidrug efflux pump obtained by electron cryo-tomography and subtomogram averaging. The fully assembled efflux pump is observed in a closed state under conditions of antibiotic challenge and in an open state in the presence of AcrB inhibitor. We also observe intermediate AcrAB complexes without TolC and discover that AcrA contacts the peptidoglycan layer of the periplasm. Our data point to a sequential assembly process in living bacteria, beginning with formation of the AcrAB subcomplex and suggest domains to target with efflux pump inhibitors.


Assuntos
Proteínas da Membrana Bacteriana Externa/metabolismo , Proteínas de Transporte/fisiologia , Proteínas de Escherichia coli/metabolismo , Proteínas de Escherichia coli/fisiologia , Escherichia coli/fisiologia , Lipoproteínas/metabolismo , Proteínas de Membrana Transportadoras/metabolismo , Proteínas Associadas à Resistência a Múltiplos Medicamentos/metabolismo , Antibacterianos/farmacologia , Proteínas de Transporte/efeitos dos fármacos , Proteínas de Transporte/ultraestrutura , Microscopia Crioeletrônica/métodos , Farmacorresistência Bacteriana Múltipla/efeitos dos fármacos , Tomografia com Microscopia Eletrônica/métodos , Escherichia coli/efeitos dos fármacos , Escherichia coli/ultraestrutura , Proteínas de Escherichia coli/antagonistas & inibidores , Proteínas de Escherichia coli/efeitos dos fármacos , Proteínas de Escherichia coli/ultraestrutura , Microscopia Intravital/métodos , Proteínas Associadas à Resistência a Múltiplos Medicamentos/antagonistas & inibidores , Peptidoglicano/metabolismo , Periplasma/metabolismo , Ligação Proteica/efeitos dos fármacos , Estrutura Quaternária de Proteína/efeitos dos fármacos
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