Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 124.270
Filtrar
1.
J Biomed Nanotechnol ; 17(5): 889-900, 2021 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-34082874

RESUMO

In the current study, we hypothesized that the electrospun scaffold chitosan (CS)/polycaprolactone (PCL)/titanium dioxide (TiO2) could be prepared by combining CS, PCL, and TiO2 nanoparticles (TiO2 NPs) using an electrospinning technique for wound dressing applications. The CS/PCL/TiO2 electrospun scaffold was prepared and characterized by UV-Vis, SEM, TEM, FTIR, and XRD analyses. Based on the UV-Vis analysis, the incorporation of CS/PCL on the surface of TiO2 NPs affected their optical properties. Further, CS/PCL and CS/PCL/TiO2 were found to have uniform distribution in fiber diameter with no bead morphology, as confirmed by SEM. The XRD spectrum of the CS/PCL/TiO2 revealed that the TiO2 NPs were adequately mixed with the CS/PCL solution, exhibiting the planes of TiO2 peaks (112), (105), (204), (116), and (301), which aligned well with the lattice structure. The antibacterial activity of CS/PCL/TiO2 against Staphylococcus aureus and Escherichia coli was evaluated using the zone of inhibition method. By testing the cytocompatibility of CS/PCL/TiO2 in vitro, this dressing was found to have a less toxic nature. In addition, In Vivo wound healing studies showed that the dressing prepared with the CS/PCL/TiO2 electrospun scaffold improved wound healing compared to that prepared with CS/PCL alone. The above results strongly support the use of CS/PCL/TiO2 electrospun scaffold as an effective dressing for wound healing.


Assuntos
Quitosana , Nanopartículas , Antibacterianos/farmacologia , Poliésteres , Titânio , Cicatrização
2.
Mater Sci Eng C Mater Biol Appl ; 126: 112109, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34082931

RESUMO

OBJECTIVE: This study aimed to construct a tightly binding antibiotic sustained release system on the polyetheretherketone (PEEK) surface and investigate the cellular activity and antibacterial properties of the new oral implant materials. METHODS: Low-temperature argon plasma under certain parameters was used to prepare P-PEEK with nano-topology, and chemical deposition technology was adopted to form a polydopamine (PDA) coating on the PEEK surface to build a biological binding platform, PDA/P-PEEK. Subsequently, vancomycin gelatin nanoparticles (Van-GNPs) were prepared by two-step desolvation method. Finally, Van-GNPs were combined with PEEK implant material surface to form a new composite material, Van-GNPs/PEEK. scanning electron microscope (SEM), atomic force microscope (AFM), energy dispersive spectrometer (EDS), and contact angle tester were used to comprehensively characterize the materials. The in vitro release test of Van was performed by dynamic dialysis with ultraviolet spectrophotometer. The cell cytotoxicity and adhesion tests were studied by mouse embryonic osteoblasts. The antibacterial properties were evaluated by bacterial adhesion test, plate colony counting, and antimicrobial ring test with Staphylococcus aureus and Streptococcus mutans. RESULTS: PEEK was treated with low-temperature argon plasma and attached to PDA to form a biological binding platform. The synthesized Van-GNPs were smooth, round, with uniform particle size distribution, and bound to PEEK to form a new composite material, which can release Van constantly. Cell experiments showed that Van-GNPs/PEEK had no cytotoxicity and had good interaction with osteoblasts. Bacterial experiments showed that surface conjugation with Van-GNPs could significantly improve the antibacterial performance of PEEK against S. aureus and S. mutans. SIGNIFICANCE: This study demonstrated that Van-GNPs/PEEK have good cellular compatibility and autonomous antibacterial properties, which provide a theoretical basis for the wide application of PEEK in the field of stomatology.


Assuntos
Anti-Infecciosos , Staphylococcus aureus , Animais , Antibacterianos/farmacologia , Preparações de Ação Retardada/farmacologia , Cetonas/farmacologia , Camundongos , Polietilenoglicóis , Propriedades de Superfície
3.
Mater Sci Eng C Mater Biol Appl ; 126: 112116, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34082933

RESUMO

In order to prepare a titanium with a low elastic modulus and good antibacterial property to meet the requirements as a biomedical material, Ti-13Nb-13Zr-5Cu (TNZ-5Cu) alloy was prepared by high vacuum consume electric arc melting furnace and then subjected to a solution treatment at 950 °C followed by a short-term aging treatment at 600 °C, for 15 min, 30 min, 1 h and 2 h, respectively. The microstructure, mechanical property, antibacterial property and biocompatibility of TNZ-5Cu were investigated in detail. The research results have shown that the solid solution treated alloy was mainly composed of ß-phase and α″-phase, while the aged alloys of ß-phase, α″-phase, α-phase and Ti2Cu. Compared with Ti-13Nb-13Zr alloy (65 GPa) and Ti-6Al-4 V alloy (111 GPa), the elastic modulus of TNZ-5Cu alloy after solution treatment was about 72 GPa and increased with the aging treatment up to 85 GPa, and the hardness was maintained at a higher level than that of Ti-13Nb-13Zr alloys (288 HV). The bacteria plate count results showed that the antibacterial ability of TNZ-5Cu alloy increased with the extension of the aging duration from <60% at 15-30 min to >90% at 1-2 h. Cell experiments showed that all TNZ-5Cu alloy had good cell compatibility. The low modulus and the antibacterial property could provide potential to avoid stress shield and device-related inflection in the clinical application.


Assuntos
Ligas , Titânio , Ligas/farmacologia , Antibacterianos/farmacologia , Materiais Biocompatíveis , Módulo de Elasticidade , Teste de Materiais , Titânio/farmacologia
4.
Mater Sci Eng C Mater Biol Appl ; 126: 112121, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34082938

RESUMO

High-performance conjugated microporous polymer (CMP)/TiO2 photocatalytic antibacterial nanocomposites were successfully synthesized by in situ Sonogashira polymerization. TiO2 was uniformly dispersed onto the surface and within the CMP which show the microporous nature with narrow pore size distribution. The high crystallinity and thermal stability of the CMP/TiO2 nanocomposites are attractive for use as antibacterial materials. The composites we prepared showed excellent photocatalytic antibacterial properties for the inactivation of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) under visible light irradiation. The photocatalytic antibacterial rates of nanocomposites against E. coli and S. aureus after 120 min of visible light irradiation were 98.14% and 100%, respectively. The superoxide anion (O2-) was confirmed to be an important substance in the antibacterial process above. The cytocompatibility of the antibacterial agents was studied in terms of cytotoxicity against NIH 3T3 fibroblasts. More than 95% of the cells were still alive in the presence of the nanocomposites, both without and with light irradiation, indicating the good cytocompatibility of the nanocomposites. Judging from the excellent photocatalytic antibacterial properties and ultralow toxicity of nanocomposites, these materials can be used in many fields such as medical treatment, transportation and construction.


Assuntos
Escherichia coli , Nanocompostos , Antibacterianos/farmacologia , Catálise , Luz , Polímeros , Staphylococcus aureus , Titânio
5.
Mater Sci Eng C Mater Biol Appl ; 126: 112146, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34082957

RESUMO

In this research work, facile, economical and eco-benign experimental procedure were adopted to synthesize Au/MgO nanocomposite with the help of Tagetes minuta leaves extract. Phytochemicals present in the leaves of Tagetes minuta were acting as reducing and stabilizing agents to avoid aggregation of nanomaterials during the preparation of Au/MgO nanocomposite. The biologically synthesized nanocomposite were systematically characterized by UV-vis spectroscopy, Scanning electron microscope (SEM), X-ray diffraction (XRD), Fourier transform infrared microscopy (FTIR), High resolution transmission electron microscopy (HRTEM), Thermogravimetric analysis (TGA), dynamic light scattering (DLS) and elemental mapping. UV-visible spectrum confirmed the presence of MgO and Au due to the presence of two SPR peaks at 315 nm and 528 nm, respectively. Moreover, the Au/MgO nanocomposite exhibited superior photocatalytic, antibacterial, hemolytic, and antioxidant activities. Photocatalytic performance tests of Au/MgO nanocomposite were- appraised by the rapid degradation of the methylene blue (MB) under UV light illumination. More importantly, after four successive cycles of MB degradation, the photocatalytic efficacy remained unchanged, which ensures the stability of the Au/MgO nanocomposite. Furthermore, the antibacterial tests showed that the advanced nanocomposite inhibited the growth of Escherichia coli, Bacillus subtilis, and Staphylococcus aureus with zones of inhibition 18 (±0.3), 21 (±0.5), and 19 (±0.4) mm, respectively. The cytotoxicity study revealed that Au/MgO nanocomposite is nontoxic to ordinary healthy RBCs. Interestingly, the Au/MgO nanocomposite also possesses an excellent antioxidant activity, whereby effectively scavenging 82% stable and harmful DPPH. Overall, the present study concludes that eco-benign Au/MgO nanocomposite has excellent potential for the remediation of bacterial pathogens and degradation of MB.


Assuntos
Nanopartículas Metálicas , Nanocompostos , Tagetes , Antibacterianos/farmacologia , Catálise , Óxido de Magnésio , Testes de Sensibilidade Microbiana , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios X
6.
Mater Sci Eng C Mater Biol Appl ; 126: 112158, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34082963

RESUMO

The growing threat of bacterial resistance to antibiotics is driving an increasing need for new antimicrobial strategies. This work demonstrates the potential of magnesium oxychloride cements (MOC) to be used as inorganic antimicrobial biomaterials for bone augmentation. An injectable formulation was identified at a powder to liquid ratio of 1.4 g mL-1, with an initial setting time below 30 mins and compressive strength of 35 ± 9 MPa. Supplementation with Ag3PO4 to enhance the antimicrobial efficacy of MOC was explored, and shown via real time X-ray diffraction to retard the formation of hydrated oxychloride phases by up to 30%. The antimicrobial efficacy of MOC was demonstrated in vitro against Staphylococcus aureus and Pseudomonas aeruginosa, forming zones of inhibition and significantly reducing viability in broth culture. Enhanced efficacy was seen for silver doped formulations, with complete eradication of detectable viable colonies within 3 h, whilst retaining the cytocompatibility of MOC. Investigating the antimicrobial mode of action revealed that Mg and Ag release and elevated pH contributed to MOC efficacy. Sustained silver release was demonstrated over 14 days, suggesting the Ag3PO4 modified formulation offers two mechanisms of infection treatment, combining the inherent antimicrobial properties of MOC with controlled release of inorganic antimicrobials.


Assuntos
Anti-Infecciosos , Magnésio , Antibacterianos/farmacologia , Anti-Infecciosos/farmacologia , Cimentos para Ossos , Suplementos Nutricionais , Magnésio/farmacologia , Teste de Materiais , Fosfatos , Compostos de Prata
7.
Mater Sci Eng C Mater Biol Appl ; 126: 112167, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34082968

RESUMO

The spread of multidrug-resistant (MDR) bacterial infections has become a serious global threat. We introduce multi-layer coated gold nanoparticles (MLGNPs) delivering antisense oligonucleotides (ASOs) targeting the resistance gene of methicillin-resistant Staphylococcus aureus (MRSA), as a selective antimicrobial by restoring susceptibility. MLGNPs were prepared by multi-step surface immobilization of gold nanoparticles (GNPs) with polyethylenimine (PEI) and loaded with ASO targeting the mecA gene. The MLGNPs were shown to be efficiently internalized into various types of Gram-positive bacteria, including MRSA, Staphylococcus epidermidis, and Bacillus subtilis, which was superior to single-layer coated GNPs and free PEI polymer. The delivery of MLGNPs into MRSA resulted in up to 74% silencing of the mecA gene with high selectivity, in a dose-dependent manner. The treatment of MLGNPs to MRSA in the presence of oxacillin, a beta-lactam antibiotic, showed major suppression (~71%) of bacterial growth, due to the recovery of antibacterial sensitivity. Furthermore, the treatment of MLGNPs in a complex system showed preferential uptake into bacteria over mammalian cells, demonstrating the suitable characteristics of MLGNPs for selective delivery into bacteria. The current approach can be potentially applied for targeting various types of MDR bacterial infections by specific silencing of a resistance gene, as a combinatorial therapeutic used with conventional antibiotics.


Assuntos
Nanopartículas Metálicas , Staphylococcus aureus Resistente à Meticilina , Infecções Estafilocócicas , Animais , Antibacterianos/farmacologia , Proteínas de Bactérias , Ouro , Resistência a Meticilina , Testes de Sensibilidade Microbiana , Oligonucleotídeos Antissenso , Proteínas de Ligação às Penicilinas/genética
8.
Mater Sci Eng C Mater Biol Appl ; 126: 112171, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34082972

RESUMO

The lack of antibacterial properties limits the application of bacterial cellulose hydrogels in wound dressings. To overcome this deficiency, silver nanoparticles (AgNPs) were introduced as antibacterial agents into a polyvinyl alcohol (PVA)/bacterial cellulose (BC) solution. A freeze-thaw method promoted formation of PVA/BC/Ag hydrogels and improved their mechanical properties. The physicochemical and biological properties of this hydrogel were systematically characterized. Those results showed the hydrogels contained a porous three-dimensional reticulum structure and had high mechanical properties. Also, the hydrogels possessed outstanding antibacterial properties and good biocompatibilities. More importantly, it effectively repaired wound defects in mice models and wound healing reached 97.89% within 15 days, and far exceeded other groups and indicated its potential for use in wound treatment applications.


Assuntos
Nanopartículas Metálicas , Álcool de Polivinil , Animais , Antibacterianos/farmacologia , Celulose/farmacologia , Hidrogéis/farmacologia , Camundongos , Prata/farmacologia , Cicatrização
9.
Mater Sci Eng C Mater Biol Appl ; 126: 112177, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34082977

RESUMO

Wound infections have consistently been recognized as serious threats to human. The design of antimicrobial and biocompatible wound dressings for infected wounds is an area of constant research. Herein, we homogeneously synthesized an ultrabroad-spectrum antimicrobial and biocompatible quaternized chitin derivative (QC-4) in a high-efficiency and sustainable route using aqueous KOH/urea solution. Particularly, QC-4 displayed powerful multidrug resistant bacteria-killing activities even at a very low antimicrobial concentration range from 500 ng/mL to 5 µg/mL, including clinically prevalent multidrug-resistant Escherichia coli (MDR-E. coli), methicillin resistant Staphylococcus aureus (MRSA), multidrug-resistant Pseudomonas aeruginosa (MRPA), and multidrug-resistant Acinetobacter baumannii (MDR-A. baumannii). With the aim to facilitate clinical translation, we validated the biocompatibility and safety of QC-4 both in vitro and in vivo, and further assessed the effects of QC-4 on infected wound healing in a porcine infectious full-thickness skin wound model. QC-4 demonstrated significant reduction of microbial aggregates and enhanced wound-healing effects by promoted re-epithelialization and collagen deposition, which were quite comparable to that of commercial Alginate-Ag dressing and absolutely superior to commercial Chitoclot Bandage dressing. Additionally, we provided clear evidences that QC-4 had a unique mechanism of action by attracting electrostatically to the negatively charged microbial surface, thus damaging the microbial cell wall and membrane. Findings of this work provided robust preclinical rationale for the future translational applications of QC-4 as a novel ultrabroad-spectrum and multidrug resistant bacteria-killing antimicrobial wound dressing for clinical wound management.


Assuntos
Staphylococcus aureus Resistente à Meticilina , Infecção dos Ferimentos , Animais , Antibacterianos/farmacologia , Quitina , Escherichia coli , Homicídio , Humanos , Testes de Sensibilidade Microbiana , Suínos , Cicatrização
10.
An Acad Bras Cienc ; 93(2): e20190343, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34076085

RESUMO

The chemical composition and biological activity of the essential oil extracted from the fresh leaves and stem bark of Grewia lasiocarpa was determined for the first time in this study. The essential oils were extracted by hydrodistillation and identified by GC-MS and FTIR. The antibacterial, antioxidant activity and total phenolic content of essential oils were determined. The major compounds identified were phytol (22.6%); α-farnesene (8.62%); n-hexadecanoic acid (7.24%); farnesol (4.61%) in the leaves, and 2-methylheptadecane (7.24%); heptacosane (7.60%); heptadecane, 2,6,10,14-tetramethyl (7.30%). The presence of aromatic, alkanes and phenolic compounds were revealed by FTIR analysis. The in silico oral prediction shows that some of the components are orally safe. The essential oil from the leaves showed cytotoxic activity at 1mg/mL(IC50 =555.70 µg/mL) against HeLa cells. The oils exhibited no significant antioxidant activity (IC50 >1 000 µg/mL) with <100 mg/g GAE of total phenol. The essential oils showed different degrees of activities against Escherichia coli (ATCC 25922), Pseudomonas aeruginosa (ATCC 27853) and Klebsiella pneumoniae (ATCC 314588) at 10 µg/mL, 5 µg/mL and 2.5 µg/mL. These results might provide a future reference basis for further exploration of more of its medicinal application.


Assuntos
Grewia , Óleos Voláteis , Antibacterianos/farmacologia , Antioxidantes , Células HeLa , Humanos , Testes de Sensibilidade Microbiana , Óleos Voláteis/farmacologia , Óleos Vegetais
11.
J Int Med Res ; 49(6): 3000605211016376, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-34082582

RESUMO

OBJECTIVE: To investigate the prevalence of mutations in domain V of Mycoplasma pneumoniae (MP) 23S ribosomal RNA (rRNA) and the clinical characteristics of pediatric MP pneumonia (MPP) in Nanjing, China. METHODS: Domain V of 23S rRNA was sequenced in MP strains collected from children diagnosed with MPP in Nanjing. Clinical and laboratory data were obtained. RESULTS: Among the 276 MP strains, 255 (92.39%) harbored mutations, primarily A2063G in domain V of MP 23S rRNA. When children were stratified according to the presence or absence of mutations, no significant differences were found in sex, age, the MP DNA load at enrollment, lymphocyte counts, pulmonary complications, immunomodulator levels, fever duration, the duration of fever after macrolide therapy, and hospital stay. The prevalence of refractory MPP in the two groups was similar. Children with refractory MPP exhibited higher MP DNA loads than those with non-refractory MPP. CONCLUSIONS: Despite the high prevalence of the A2063G mutation in domain V of MP 23S rRNA, mutations were not associated with the clinical characteristics of MPP. The MP DNA load significantly differed between refractory and non-refractory MPP.


Assuntos
Pneumonia por Mycoplasma , RNA Ribossômico 23S , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Criança , China/epidemiologia , Farmacorresistência Bacteriana/genética , Humanos , Mutação , Mycoplasma pneumoniae/genética , Pneumonia por Mycoplasma/diagnóstico , Pneumonia por Mycoplasma/tratamento farmacológico , Pneumonia por Mycoplasma/epidemiologia , RNA Ribossômico 23S/genética
12.
Food Chem ; 358: 129833, 2021 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-33933967

RESUMO

This study identified and quantified hydrolysable tannins (HTs) in Terminalia ferdinandiana Exell (Kakadu plum) fruit, freeze dried powder extracted with 80% aqueous acetone (AA) and 80% aqueous acidified ethanol (AAE), using UHPLC-Q/Orbitrap/MS/MS. The vitamin C and ellagic acid were quantified by UHPLC-PDA. A total of seven HTs were identified: corilagin, 3,4,6-tri-O-galloyl-ß-d-glucose, elaeocarpusin, chebulinic acid, chebulagic acid, helioscopin B, and punicalagin, with five classified as ellagitannins. The two extracts AA and AAE, comprised of gallic acid (2.5 and 2.2 mg/g DW), punicalagins α and ß (2.8 and 1.3 mg/g DW), respectively, and both contained ellagic acid (~4 g/100 g DW). These extracts showed high antioxidant properties and strong antimicrobial effects against methicillin-resistant Staphylococcus aureus clinical isolate, Staphylococcus aureus, and Shewanella putrefaciens. These results suggest that Kakadu plum fruit is a rich, edible source of ellagitannins, ellagic acid and vitamin C with potential applications in food, cosmetic and nutraceutical industries.


Assuntos
Antibacterianos/farmacologia , Antioxidantes/farmacologia , Taninos Hidrolisáveis/química , Taninos Hidrolisáveis/farmacologia , Terminalia/química , Antibacterianos/química , Antioxidantes/química , Etanol/química , Liofilização , Frutas/química , Glucosídeos/análise , Glucosídeos/química , Taninos Hidrolisáveis/análise , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Extratos Vegetais/química , Pós , Solventes , Espectrometria de Massas em Tandem
13.
Poult Sci ; 100(6): 101094, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33989952

RESUMO

The study was carried out to estimate the burden and pattern of antibiotic resistance and to identify antibiotic resistance genes with focus on ESBL producers, plasmid mediated quinolone resistance, and tetracycline efflux genes, in faecal bacterial isolates collected from poultry farms of coastal Southern Karnataka, India. High resistance to fluoroquinolones was observed with 94% Escherichia coli and 80% Klebsiella pneumoniae being resistant to both ciprofloxacin and levofloxacin. All the Escherichia coli strains were resistant to tetracycline (100%). qnrB (38%) was the most common gene detected followed by qnrS (27%) and qnrA (21.5%). All Klebsiella pneumoniae isolates resistant to tetracycline harbored tetA gene. Most of the isolates in our study had high MAR indices indicating rampant use of antibiotics.


Assuntos
Infecções por Escherichia coli , Klebsiella pneumoniae , Animais , Antibacterianos/farmacologia , Galinhas , Farmacorresistência Bacteriana/genética , Escherichia coli/genética , Infecções por Escherichia coli/epidemiologia , Infecções por Escherichia coli/veterinária , Índia , Klebsiella pneumoniae/genética , Testes de Sensibilidade Microbiana/veterinária , Fenótipo
14.
Nat Commun ; 12(1): 2879, 2021 05 17.
Artigo em Inglês | MEDLINE | ID: mdl-34001879

RESUMO

As whole-genome sequencing capacity becomes increasingly decentralized, there is a growing opportunity for collaboration and the sharing of surveillance data within and between countries to inform typhoid control policies. This vision requires free, community-driven tools that facilitate access to genomic data for public health on a global scale. Here we present the Pathogenwatch scheme for Salmonella enterica serovar Typhi (S. Typhi), a web application enabling the rapid identification of genomic markers of antimicrobial resistance (AMR) and contextualization with public genomic data. We show that the clustering of S. Typhi genomes in Pathogenwatch is comparable to established bioinformatics methods, and that genomic predictions of AMR are highly concordant with phenotypic susceptibility data. We demonstrate the public health utility of Pathogenwatch with examples selected from >4,300 public genomes available in the application. Pathogenwatch provides an intuitive entry point to monitor of the emergence and spread of S. Typhi high risk clones.


Assuntos
Antibacterianos/farmacologia , Farmacorresistência Bacteriana Múltipla/genética , Salmonella typhi/efeitos dos fármacos , Febre Tifoide/prevenção & controle , Proteínas de Bactérias/genética , Genoma Bacteriano/genética , Genômica/métodos , Genótipo , Geografia , Humanos , Malaui , Proteínas de Membrana Transportadoras/genética , Testes de Sensibilidade Microbiana/métodos , Mutação , Salmonella typhi/genética , Salmonella typhi/fisiologia , Tanzânia , Febre Tifoide/microbiologia
16.
Nanoscale ; 13(21): 9864-9872, 2021 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-34037034

RESUMO

Current strategies for the design of antibacterial peptides show limitations in the development of assembled antibacterial peptides due to the challenges in simultaneously balancing the antibacterial activity and assembling behavior. Herein, we report on one strategy for the design of antibacterial peptides derived from virulent amyloids and investigate their self-assembly into nanostructures with remarkable antibacterial activity. The peptides were either directly truncated from virulent amyloid peptide PSM α3 or mutated from the original sequence by replacing the lysine and phenylalanine residues with arginine or tryptophan, leading to three undecapeptides. Conformational and morphological results indicated the formation of nanotubes and twisted nanoribbons by the truncated peptide and the mutated peptide, respectively, predominately driven by anti-parallel ß-sheets. Bacterial culturing experiments revealed that the two mutated peptides possessed remarkable antibacterial activity against both Gram-positive and Gram-negative bacteria by disrupting the bacterial membrane at a concentration above their critical aggregation concentrations, thus leading to two nanoantibacterials. Our findings demonstrate that biomimetic peptides originated from virulent amyloids exhibit great potential in the development of assembled antibacterial peptides, thus providing a new strategy for simultaneously addressing the antibacterial activity and pharmacokinetics of natural antibacterial peptides in the future.


Assuntos
Antibacterianos , Anti-Infecciosos , Antibacterianos/farmacologia , Bactérias Gram-Negativas , Bactérias Gram-Positivas , Peptídeos
17.
Pestic Biochem Physiol ; 175: 104849, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33993967

RESUMO

Staphylococcus aureus resistance poses nonnegligible threats to the livestock industry. In light of this, carbazole-oxadiazoles were designed and synthesized for treating S. aureus infection. Bioassay discovered that 3,6-dibromocarbazole derivative 13a had effective inhibitory activities to several Gram-positive bacteria, in particular to S. aureus, S. aureus ATCC 29213, MRSA and S. aureus ATCC 25923 (MICs = 0.6-4.6 nmol/mL), which was more active than norfloxacin (MICs = 6-40 nmol/mL). Subsequent studies showed that 3,6-dibromocarbazole derivative 13a acted rapidly on S. aureus ATCC 29213 and possessed no obvious tendency to induce bacterial resistance. Further evaluations indicated that 3,6-dibromocarbazole derivative 13a showed strong abilities to disrupt bacterial biofilm and interfere with DNA, which might be the power sources of antibacterial performances. Moreover, 3,6-dibromocarbazole derivative 13a also exhibited slight cell lethality toward Hek 293 T and LO2 cells and low hemolytic toxicity to red blood cells. The above results implied that the active molecule 13a could be studied in the future development of agricultural available antibiotics.


Assuntos
Staphylococcus aureus Resistente à Meticilina , Staphylococcus aureus , Antibacterianos/farmacologia , Carbazóis/farmacologia , Células HEK293 , Humanos , Testes de Sensibilidade Microbiana , Oxidiazóis
18.
Pestic Biochem Physiol ; 175: 104857, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33993975

RESUMO

To discover new nematicides, a series of novel amide derivatives containing an imidazo[1,2-a]pyridine moeity were designed and synthesized. Among the title compounds, compounds 3 and 27 exhibited good nematicidal activities against Aphelenchoides besseyi (rice white-tip nematode), with LC50 values against of 27.3 and 35.9 mg/L, respectively, which were superior to that of fosthiazate (45.4 mg/L). Meanwhile, the LC50 value of compound 27 against Caenorhabditis elegans was 5.7 mg/L, which was superior to that of fosthiazate (77.2 mg/L). Compound 27 not only binds well to acetylcholinesterase (AChE) of nematodes, but also has a good inhibitory activity against AChE. Thus, AChE may be a potential target of compound 27 against nematodes. Unexpectedly, compound 28 exhibited excellent antibacterial activities with EC50 values of 1.2 and 3.1 mg/L against Xanthomonas oryzae pv. oryzae (Xoo) and Xanthomonas oryzae pv. oryzicola (Xoc), respectively, which were superior to those of bismerthiazol (68.6 and 77.1 mg/L) and thiodiazole copper (80.8 and 96.6 mg/L). The curative and protective activities of compound 28 against bacterial leaf blight were 37.0% and 36.8% at 50 mg/L, respectively, which were higher than those of thiodiazole copper (16.1% and 15.5%). In addition, compound 28 may inhibit the growth of Xoo by affecting the production of cell membranes and extracellular polysaccharides. Amide derivatives containing an imidazo[1,2-a]pyridine moeity can be used as good lead-structures to discover new nematicidal and antibacterial agents in the future.


Assuntos
Oryza , Xanthomonas , Amidas , Antibacterianos/farmacologia , Testes de Sensibilidade Microbiana , Oxidiazóis , Doenças das Plantas , Piridinas/farmacologia
19.
Oxid Med Cell Longev ; 2021: 5518825, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33936381

RESUMO

Due to the challenges of antibiotic resistance to global health, bacteriocins as antimicrobial compounds have received more and more attention. Bacteriocins are biosynthesized by various microbes and are predominantly used as food preservatives to control foodborne pathogens. Now, increasing researches have focused on bacteriocins as potential clinical antimicrobials or immune-modulating agents to fight against the global threat to human health. Given the broad- or narrow-spectrum antimicrobial activity, bacteriocins have been reported to inhibit a wide range of clinically pathogenic and multidrug-resistant bacteria, thus preventing the infections caused by these bacteria in the human body. Otherwise, some bacteriocins also show anticancer, anti-inflammatory, and immune-modulatory activities. Because of the safety and being not easy to cause drug resistance, some bacteriocins appear to have better efficacy and application prospects than existing therapeutic agents do. In this review, we highlight the potential therapeutic activities of bacteriocins and suggest opportunities for their application.


Assuntos
Antibacterianos/uso terapêutico , Bacteriocinas/uso terapêutico , Antibacterianos/farmacologia , Bacteriocinas/farmacologia , Humanos
20.
Mater Sci Eng C Mater Biol Appl ; 125: 112083, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33965099

RESUMO

Calcium carbonate is used as bone-filling material due to its good biocompatibility, bioactivity, and bioabsorbability, but the prevalence of infectious complications associated with calcium carbonate has created a persisting challenge in the treatment of bone defect. Therefore, this greatly necessitate the need to endow calcium carbonate with antibacterial properties. In this study, calcium carbonate powders loaded with silver nanoparticles (Ag-CaCO3) were prepared in attempt to serve as a novel antibacterial inorganic filler material. This objective was achieved using ultrasonic spray-pyrolysis (USSP) route to produce Ag-CaCO3 with 1, 5 and 10 mol% silver. The size of silver nanoparticles on CaCO3 microspheres could be regulated by adjusting silver concentration to facilitate effective release of Ag+ ions. This was demonstrated in Ag-CaCO3 (1), where the lowest silver content at 1 mol% achieved the highest Ag+ ions release over 28 days. This in turn gave rise to effective antibacterial efficiency against Staphylococcus aureus and Escherichia coli. Furthermore, CaCO3 (1) could also support osteoblast-like cells (MG-63) at a cell viability of 80%. Overall, this work extends the capabilities in employing USSP to produce inorganic filler materials with sustained antibacterial properties, bringing one step closer to the development of antibacterial products.


Assuntos
Nanopartículas Metálicas , Prata , Antibacterianos/farmacologia , Carbonato de Cálcio/farmacologia , Preparações de Ação Retardada , Testes de Sensibilidade Microbiana , Prata/farmacologia , Ultrassom
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...