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1.
Artigo em Inglês | MEDLINE | ID: mdl-38603548

RESUMO

In this study, hydrogels were produced using a Schiff base reaction between two hyaluronic acid derivatives: one containing aldehyde groups (HA-Ald) and the other holding a diethylenetriamine with terminal amino groups (HA-DETA). The DETA portion promotes the in situ growth, complexation, and stabilization of silver nanoparticles (AgNPs), eliminating the need for external reducing agents. The reaction between HA-DETA and HA-Ald leads to the formation of imine bonds, which results in dynamically pH-responsive cross-linking. While the DETA capping ability helped in embedding the AgNPs, the on/off pH environmental responsivity of the hydrogel allows for a controlled and on-demand release of the drug, mainly when bacterial infections cause pH variation of the wound bed. The injectable hydrogels resulted in being highly compatible in contact with blood red cells, fibroblasts, and keratinocytes and capable of having a proliferative effect on an in vitro wound scratch model. The pH-responsive hydrogels showed proper antibacterial activity againstPseudomonas aeruginosaandStaphylococcus aureus, common bacterial strains presented in wound infections. Finally, in vivo wound model studies demonstrated an overall speeding up in the wound healing rate and advanced wound conditions in the experimental group treated with the hydrogels compared to control samples.

2.
Mar Drugs ; 22(3)2024 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-38535474

RESUMO

Biofilm-associated infections pose significant challenges in healthcare settings due to their resistance to conventional antimicrobial therapies. In the last decade, the marine environment has been a precious source of bioactive molecules, including numerous derivatives with antibiofilm activity. In this study, we reported the synthesis and the biological evaluation of a new series of twenty-two thiadiazopyrimidinone derivatives obtained by using a hybridization approach combining relevant chemical features of two important classes of marine compounds: nortopsentin analogues and Essramycin derivatives. The synthesized compounds were in vitro tested for their ability to inhibit biofilm formation and to disrupt mature biofilm in various bacterial strains. Among the tested compounds, derivative 8j exhibited remarkable dispersal activity against preformed biofilms of relevant Gram-positive and Gram-negative pathogens, as well as towards the fungus Candida albicans, showing BIC50 values ranging from 17 to 40 µg/mL. Furthermore, compound 8j was in vivo assayed for its toxicity and the anti-infective effect in a Galleria mellonella model. The results revealed a promising combination of anti-infective properties and a favorable toxicity profile for the treatment of severe chronic biofilm-mediated infections.


Assuntos
Tiadiazóis , Biofilmes , Bioensaio , Candida albicans , Hibridização Genética
3.
Int J Mol Sci ; 24(6)2023 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-36982723

RESUMO

The demand for new molecules to counter bacterial resistance to antibiotics and tumor cell resistance is increasingly pressing. The Mediterranean seagrass Posidonia oceanica is considered a promising source of new bioactive molecules. Polypeptide-enriched fractions of rhizomes and green leaves of the seagrass were tested against Gram-positive (e.g., Staphylococcus aureus, Enterococcus faecalis) and Gram-negative bacteria (e.g., Pseudomonas aeruginosa, Escherichia coli), as well as towards the yeast Candida albicans. The aforementioned extracts showed indicative MIC values, ranging from 1.61 µg/mL to 7.5 µg/mL, against the selected pathogens. Peptide fractions were further analyzed through a high-resolution mass spectrometry and database search, which identified nine novel peptides. Some discovered peptides and their derivatives were chemically synthesized and tested in vitro. The assays identified two synthetic peptides, derived from green leaves and rhizomes of P. oceanica, which revealed interesting antibiofilm activity towards S. aureus, E. coli, and P. aeruginosa (BIC50 equal to 17.7 µg/mL and 70.7 µg/mL). In addition, the natural and derivative peptides were also tested for potential cytotoxic and apoptosis-promoting effects on HepG2 cells, derived from human hepatocellular carcinomas. One natural and two synthetic peptides were proven to be effective against the "in vitro" liver cancer cell model. These novel peptides could be considered a good chemical platform for developing potential therapeutics.


Assuntos
Alismatales , Neoplasias , Humanos , Staphylococcus aureus , Escherichia coli , Peptídeos/farmacologia , Antibacterianos/farmacologia , Antibacterianos/química , Pseudomonas aeruginosa , Alismatales/química , Testes de Sensibilidade Microbiana
4.
Int J Mol Sci ; 23(23)2022 Dec 06.
Artigo em Inglês | MEDLINE | ID: mdl-36499703

RESUMO

The development of biomedical systems with antimicrobial and antibiofilm properties is a difficult medical task for preventing bacterial adhesion and growth on implanted devices. In this work, a fibrillar scaffold was produced by electrospinning a polymeric organic dispersion of polylactic acid (PLA) and poly(α,ß-(N-(3,4-dihydroxyphenethyl)-L-aspartamide-co-α,ß-N-(2-hydroxyethyl)-L-aspartamide) (PDAEA). The pendant catechol groups of PDAEA were used to reduce silver ions in situ and produce silver nanoparticles onto the surface of the electrospun fibers through a simple and reproducible procedure. The morphological and physicochemical characterization of the obtained scaffolds were studied and compared with virgin PLA electrospun sample. Antibiofilm properties against Pseudomonas aeruginosa, used as a biofilm-forming pathogen model, were also studied on planar and tubular scaffolds. These last were fabricated as a proof of concept to demonstrate the possibility to obtain antimicrobial devices with different shape and dimension potentially useful for different biomedical applications. The results suggest a promising approach for the development of antimicrobial and antibiofilm scaffolds.


Assuntos
Anti-Infecciosos , Nanopartículas Metálicas , Prata/farmacologia , Prata/química , Nanopartículas Metálicas/química , Pseudomonas aeruginosa , Biofilmes , Antibacterianos/farmacologia , Antibacterianos/química
5.
Antibiotics (Basel) ; 11(12)2022 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-36551449

RESUMO

The defense system of freshwater crayfish Procambarus clarkii as a diversified source of bioactive molecules with antimicrobial properties was studied. Antimicrobial activity of two polypeptide-enriched extracts obtained from hemocytes and hemolymph of P. clarkii were assessed against Gram positive (Staphylococcus aureus, Enterococcus faecalis) and Gram negative (Pseudomonas aeruginosa, Escherichia coli) bacteria and toward the yeast Candida albicans. The two peptide fractions showed interesting MIC values (ranging from 11 to 700 µg/mL) against all tested pathogens. Polypeptide-enriched extracts were further investigated using a high-resolution mass spectrometry and database search and 14 novel peptides were identified. Some peptides and their derivatives were chemically synthesized and tested in vitro against the bacterial and yeast pathogens. The analysis identified a synthetic derivative peptide, which showed an interesting antifungal (MIC and MFC equal to 31.2 µg/mL and 62.5 µg/mL, respectively) and antibiofilm (BIC50 equal to 23.2 µg/mL) activities against Candida albicans and a low toxicity in human cells.

6.
Int J Pharm ; 627: 122257, 2022 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-36195284

RESUMO

The development of wound dressings with combined antioxidant, antibacterial and tissue adhesion functions has been a difficult medical task for the treatment of wound infections. We synthetized a dopamine and PEG functionalized Gellan Gum (GG) to produce an injectable hydrogel with radical scavenging activity having both specific and aspecific antibiotic/antimicrobial properties. Using starting GG with different molecular weights, we obtained two derivatives that have been used to prepare the gel precursor dispersion, that undergoes gelation in the presence of colistin and dried microparticles (MPs) functionalized on the surface with polydopamine (pDA). Both were used to dope the hydrogel, increase the radical scavenger activity and impart near-infrared light (NIR) responsiveness. Indeed, with an irradiation of 810 nm, the incorporated microparticles exhibit photothermal transformation properties and improve the release of antibiotics on demand. The combination of photothermal and antibiotic therapy with synergistic antibacterial action acts on Pseudomonas aeruginosa and leads to a bactericidal effect in a few hours, while on Staphylococcus aureus there is an effect of inhibition of growth over time due only to the hyperthermic effect. We believe this study provides a promising method for fabricating a multifunctional injectable hydrogel for the potential treatment of infected skin wounds.


Assuntos
Hipertermia Induzida , Infecção dos Ferimentos , Humanos , Hidrogéis/farmacologia , Antioxidantes/farmacologia , Dopamina , Colistina/farmacologia , Antibacterianos/farmacologia , Cicatrização , Infecção dos Ferimentos/tratamento farmacológico
7.
Carbohydr Polym ; 295: 119861, 2022 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-35988982

RESUMO

In this work a synthetic protocol for the functionalization of hyaluronic acid with diethylenetriamine (DETA) was standardized. HA-DETA derivatives were characterized by NMR and proton carbon correlation analysis HSQC and HMBC to confirm chemical structure. A selected derivative was used to set up a green fabrication procedure for HA-DETA capped silver nanoparticles with the aim to achieve a polymeric based coating with potential application in the treatment of medical devices associated infections. Data from UV-visible spectroscopy, electron scanning and transmission microscope (STEM), photoelectric spectroscopy (XPS) and rheological characterization were combined to characterize the HA-DETA/Ag nanocomposites. HA-DETA stabilized Ag nanoparticles (10-30 nm) were obtained through an UV accelerated production. The viability of MC3T3-E1 was analyzed with the aim of designing a cytocompatible antimicrobial coating. Antibacterial and antibiofilm activity of HA-DETA/Ag nanocomposites have been tested in vitro against Staphylococcus aureus and Pseudomonas aeruginosa both in culture plates than on titanium specimens.


Assuntos
Nanopartículas Metálicas , Prata , Antibacterianos/química , Antibacterianos/farmacologia , DEET , Ácido Hialurônico , Nanopartículas Metálicas/química , Poliaminas , Prata/química , Prata/farmacologia
8.
Int J Biol Macromol ; 214: 470-479, 2022 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-35760161

RESUMO

Here we reported the fabrication of an electrospun membrane based on a hyaluronic acid derivative (HA-EDA) to be used as a bandage for the potential treatment of chronic wounds. The membrane, loaded with graphene oxide (GO) and ciprofloxacin, showed photothermal properties and light-triggered drug release when irradiated with a near-infrared (NIR) laser beam. Free amino groups of HA-EDA derivative allowed autocrosslinking of the electrospun membrane; thus, a substantial enhancement in the hydrolytic resistance of the patch was obtained. In vitro antibacterial activity studies performed on Staphylococcus aureus and Pseudomonas aeruginosa revealed that such electrospun membranes, due to the synergistic effect of the antibiotic and NIR-mediated hyperthermia, reduced the viability of both pathogens. Specific in vitro experiment demonstrated also that is possible to disrupt, through laser irradiation, the biofilms formed onto the membrane.


Assuntos
Grafite , Infecções Estafilocócicas , Infecção dos Ferimentos , Antibacterianos/farmacologia , Grafite/farmacologia , Humanos , Ácido Hialurônico/farmacologia , Pseudomonas aeruginosa , Staphylococcus aureus , Infecção dos Ferimentos/tratamento farmacológico
9.
Pharmaceutics ; 14(1)2022 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-35057011

RESUMO

This study reports the first enzymatic synthesis leading to several oligomer analogues of poly[3-(3,4-dihydroxyphenyl)glyceric acid]. This biopolymer, extracted from plants of the Boraginaceae family has shown a wide spectrum of pharmacological properties, including antimicrobial activity. Enzymatic ring opening polymerization of 2-methoxycarbonyl-3-(3,4-dibenzyloxyphenyl)oxirane (MDBPO) using lipase from Candida rugosa leads to formation of poly[2-methoxycarbonyl-3-(3,4-dibenzyloxyphenyl)oxirane] (PMDBPO), with a degree of polymerization up to 5. Catalytic debenzylation of PMDBPO using H2 on Pd/C yields poly[2-methoxycarbonyl-3-(3,4-dihydroxyphenyl)oxirane] (PMDHPO) without loss in molecular mass. Antibacterial assessment of natural polyethers from different species of Boraginaceae family Symhytum asperum, S. caucasicum,S. grandiflorum, Anchusa italica, Cynoglossum officinale, and synthetic polymers, poly[2-methoxycarbonyl-3-(3,4-dimethoxyphenyl)oxirane (PMDMPO) and PMDHPO, reveals that only the synthetic analogue produced in this study (PMDHPO) exhibits a promising antimicrobial activity against pathogenic strains S.aureus ATCC 25923 and E.coli ATCC 25922 the minimum inhibitory concentration (MIC) being 100 µg/mL.

10.
Dev Comp Immunol ; 126: 104258, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34530039

RESUMO

The much-publicised increased resistance of pathogenic bacteria to conventional antibiotics has focused research effort on the characterization of new antimicrobial drugs. In this context, antimicrobial peptides (AMPs) extracted from animals are considered a promising alternative to conventional antibiotics. In recent years, freshwater crayfish species have emerged as an important source of bioactive compounds. In fact, these invertebrates rely on an innate immune system based on cellular responses and on the production of important effectors in the haemolymph, such as AMPs, which are produced and stored in granules in haemocytes and released after stimulation. These effectors are active against both Gram-positive and Gram-negative bacteria. In this review, we summarise the recent progress on AMPs isolated from the several species of freshwater crayfish and their prospects for future pharmaceutical applications to combat infectious agents.


Assuntos
Antibacterianos , Peptídeos Catiônicos Antimicrobianos , Animais , Antibacterianos/química , Peptídeos Catiônicos Antimicrobianos/química , Peptídeos Antimicrobianos , Astacoidea , Água Doce , Bactérias Gram-Negativas , Bactérias Gram-Positivas
11.
Appl Microbiol Biotechnol ; 105(13): 5357-5366, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34184105

RESUMO

The widespread use of antibiotics has resulted in the outbreak and spread of antibiotic-resistant pathogens. Bacterial antibiotic resistance may develop at cellular and community levels. In the latter case, it is based on tolerance which implicates the shift from a free-living form of life (i.e., planktonic) to a sessile multi-stratified community (i.e., biofilm). Metal nanoparticles (MNPs) have been shown to be promising candidates as antimicrobial agents. MNPs are able to interact with and penetrate bacterial biofilms, thus, resulting effective antibiofilm compounds. Another interesting aspect is the possibility of using plants, fungi, yeasts, and bacteria to obtain biogenic MNPs (BMNP). Bacteria are able to grow in presence of many different toxic heavy metal ions thanks to different metal resistance gene clusters that allow a variety of biochemical counters (formation of harmless complexes, efflux, precipitation, reduction, etc.). The formation of BMNPs by bacterial cells could be, in most cases, just a consequence of metal detoxification mechanisms. This review focuses on BMNPs from bacterial origin that may represent a good source of compounds with a broad spectrum of activity against common Gram-positive and Gram-negative pathogens and bacterial biofilms thereof. In particular, the state of art on BMNP synthesis by bacteria is presented and potential applications in the fight against biofilm-associated infections and resistant pathogens are highlighted. In addition, critical aspects on BMNP bacterial synthesis and utilization are commented.Key points• New antimicrobials to fight antibiotic-resistant pathogens are urgently needed.• Biogenic metal nanoparticles can efficiently hit biofilm-forming pathogens.• Metal-nanoparticle composition could confer specific antibiofilm activity.


Assuntos
Infecções Bacterianas , Nanopartículas Metálicas , Antibacterianos/farmacologia , Bactérias , Infecções Bacterianas/tratamento farmacológico , Infecções Bacterianas/prevenção & controle , Biofilmes , Farmacorresistência Bacteriana , Humanos , Testes de Sensibilidade Microbiana
12.
Mater Sci Eng C Mater Biol Appl ; 123: 112001, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33812621

RESUMO

Here, an asymmetric double-layer membrane has been designed and fabricated by electrospinning as a tool for a potential wound healing application. A hydrophobic layer has been produced by using a polyurethane-polycaprolactone (PU-PCL) copolymer and loaded with the antibacterial ciprofloxacin whereas an ion responsive hydrophilic layer has been produced by using an octyl derivative of gellan gum (GG-C8) and polyvinyl alcohol (PVA) and loaded with the growth factor FGF-2. This study investigated how the properties of this asymmetric membrane loaded with actives, were influenced by the ionotropic crosslinking of the hydrophilic layer. In particular, the treatment in DPBS and the crosslinking in CaCl2 0.1 or 1 M of the hydrophilic layer affected the release profile of the bioactive molecules allowing to modulate both the antimicrobial effect, as assayed by logarithmic reduction of the Staphylococcus aureus viable count, and the chemoattractant properties on NIH 3 T3 cell line, as assayed by scratch test and cell chemoattraction assay.


Assuntos
Anti-Infecciosos , Nanofibras , Antibacterianos/farmacologia , Bandagens , Fatores Quimiotáticos , Ciprofloxacina/farmacologia , Preparações de Ação Retardada , Fator 2 de Crescimento de Fibroblastos
13.
Eur J Med Chem ; 209: 112892, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-33035921

RESUMO

The inhibition or prevention of biofilm formation represents an emerging strategy in the war against antibiotic resistance, interfering with key players in bacterial virulence. This approach includes the inhibition of the catalytic activity of transpeptidase sortase A (Srt A), a membrane enzyme responsible for covalently attaching a wide variety of adhesive matrix molecules to the peptidoglycan cell wall in Gram-positive strains. A new series of seventeen 1,2,4-oxadiazole derivatives was efficiently synthesized and screened as potential new anti-virulence agents. The ability of inhibiting biofilm formation was evaluated against both Gram-positive and Gram-negative pathogens. Remarkably, all these compounds inhibited S. aureus and/or P. aeruginosa biofilm formation in a dose dependent manner, with 50% biofilm inhibitory concentrations (BIC50s) below 10 µM for the most active compounds. Inhibition of SrtA was validated as one of the possible mechanisms of action of these new 1,2,4-oxadiazole derivatives, in the tested Gram-positive pathogen, using a specific enzymatic assay for a recombinant S. aureus SrtA. The three most active compounds, eliciting BIC50 values for S. aureus ATCC 25923 between 0.7 and 9.7 µM, showed a good activity toward the enzyme eliciting IC50 values ranging from 2.2 to 10.4 µM.


Assuntos
Aminoaciltransferases/antagonistas & inibidores , Antibacterianos/farmacologia , Proteínas de Bactérias/antagonistas & inibidores , Biofilmes/efeitos dos fármacos , Imidazóis/farmacologia , Indóis/farmacologia , Oxidiazóis/farmacologia , Pseudomonas aeruginosa/efeitos dos fármacos , Staphylococcus aureus/efeitos dos fármacos , Aminoaciltransferases/metabolismo , Antibacterianos/química , Proteínas de Bactérias/metabolismo , Linhagem Celular , Cisteína Endopeptidases/metabolismo , Humanos , Imidazóis/química , Indóis/química , Oxidiazóis/química , Infecções por Pseudomonas/tratamento farmacológico , Infecções por Pseudomonas/microbiologia , Pseudomonas aeruginosa/fisiologia , Infecções Estafilocócicas/tratamento farmacológico , Infecções Estafilocócicas/microbiologia , Staphylococcus aureus/fisiologia
14.
Molecules ; 26(1)2020 Dec 27.
Artigo em Inglês | MEDLINE | ID: mdl-33375417

RESUMO

Anti-virulence strategy is currently considered a promising approach to overcome the global threat of the antibiotic resistance. Among different bacterial virulence factors, the biofilm formation is recognized as one of the most relevant. Considering the high and growing percentage of multi-drug resistant infections that are biofilm-mediated, new therapeutic agents capable of counteracting the formation of biofilms are urgently required. In this scenario, a new series of 18 thiazole derivatives was efficiently synthesized and evaluated for its ability to inhibit biofilm formation against the Gram-positive bacterial reference strains Staphylococcus aureus ATCC 25923 and S. aureus ATCC 6538 and the Gram-negative strain Pseudomonas aeruginosa ATCC 15442. Most of the new compounds showed a marked selectivity against the Gram-positive strains. Remarkably, five compounds exhibited BIC50 values against S. aureus ATCC 25923 ranging from 1.0 to 9.1 µM. The new compounds, affecting the biofilm formation without any interference on microbial growth, can be considered promising lead compounds for the development of a new class of anti-virulence agents.


Assuntos
Alcaloides/farmacologia , Organismos Aquáticos/química , Biofilmes/crescimento & desenvolvimento , Imidazóis/farmacologia , Indóis/farmacologia , Pseudomonas aeruginosa/fisiologia , Staphylococcus aureus/fisiologia , Tiazóis/farmacologia , Alcaloides/química , Biofilmes/efeitos dos fármacos , Imidazóis/química , Indóis/química , Concentração Inibidora 50 , Testes de Sensibilidade Microbiana , Pseudomonas aeruginosa/efeitos dos fármacos , Staphylococcus aureus/efeitos dos fármacos , Tiazóis/síntese química , Tiazóis/química
15.
Antibiotics (Basel) ; 9(11)2020 Oct 28.
Artigo em Inglês | MEDLINE | ID: mdl-33126631

RESUMO

The present work was designed to identify and characterize novel antimicrobial peptides (AMPs) from Charybdis pancration (Steinh.) Speta, previously named Urginea maritima, is a Mediterranean plant, well-known for its biological properties in traditional medicine. Polypeptide-enriched extracts from different parts of the plant (roots, leaves and bulb), never studied before, were tested against two relevant pathogens, Staphylococcus aureus and Pseudomonas aeruginosa. With the aim of identifying novel natural AMPs, peptide fraction displaying antimicrobial activity (the bulb) that showed minimum inhibitory concentration (MICs) equal to 30 µg/mL against the above mentioned strains, was analysed by high-resolution mass spectrometry and database search. Seventeen peptides, related to seven proteins present in the investigated database, were described. Furthermore, we focused on three peptides, which due to their net positive charge, have a better chance to be AMPs and they were investigated by molecular modelling approaches, in order to shed light on the solution properties of their equilibrium structures. Some of new detected peptides could represent a good platform for the development of new antimicrobials in the fight against antibiotic resistance phenomenon.

16.
PeerJ ; 8: e9299, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32596043

RESUMO

BACKGROUND AND AIMS: Fish by-products are generally used to produce fishmeal or fertilizers, with fish oil as a by-product. Despite their importance, fish wastes are still poorly explored and characterized and more studies are needed to reveal their potentiality. The goal of the present study was to qualitatively characterize and investigate the antimicrobial effects of the fish oil extracted from Salmo salar waste samples and to evaluate the potential use of these compounds for treating pathogen infections. METHODS: Salmo salar waste samples were divided in two groups: heads and soft tissues. Fatty acids composition, and in particular the content in saturated (SAFAs), mono-unsaturated (MUFAs) and Polyunsaturated (PUFAs) fatty acids, was characterized through GC/MS Thermo Focus GC-DSQ II equipped with a ZB-5 fused silica capillary tubes column. The antimicrobial activity of the salmon waste oils was evaluated through the Minimum Inhibitory Concentration assay and the antibiotics contamination was determined by Liquid Chromatography with tandem Mass Spectrometry (LC-MS/MS) analysis. All experiments were done at least in triplicate. RESULTS: GC/MS analysis has shown the specific fatty acid composition of the salmon waste oils and their enrichment in MUFAs and PUFAs, with special reference to omega-3, -6, -7, -9 fatty acids. Furthermore, our study has highlighted the antimicrobial activity of the fish waste oil samples against two Gram+ and Gram- bacterial strains. CONCLUSIONS: These data confirm that the fish waste is still quantitatively and qualitatively an important source of available biological properties that could be extracted and utilized representing an important strategy to counteract infective diseases in the context of the circular economy.

17.
Heliyon ; 6(5): e03930, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32426542

RESUMO

Cities are currently engaged through their urban policies in pushing people towards less environmentally impacting mobility modalities: therefore, cycling and walking are strongly promoted, especially by means of new and wider limited traffic and no-cars zones. In this paper, the effectiveness of the new smartphones and apps-based technologies in modifying the mobility behaviors of citizens towards more sustainable choices has been investigated. Specifically, the potential of a smartphone app, directly involving citizens by means of a game rewarding the most sustainable trips, has been tested on a university commuters' group. These latter, starting from their current mobility situation, were challenged by an enhanced scenario characterized by more restrictive and sustainable targets. Promising results have been obtained suggesting that game-based tools could be effectively used as urban policy interventions intended to obtain a more sustainable mobility.

18.
Appl Microbiol Biotechnol ; 104(14): 6325-6336, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32462243

RESUMO

Silver nanoparticles (Ag-NPs) can be considered as a cost-effective alternative to antibiotics. In the presence of Fe(III)-citrate and Ag+, Klebsiella oxytoca DSM 29614 produces biogenic Ag-NPs embedded in its peculiar exopolysaccharide (EPS). K. oxytoca DSM 29614 was cultivated in a defined growth medium-containing citrate (as sole carbon source) and supplemented with Ag+ and either low or high Fe(III) concentration. As inferred from elemental analysis, transmission and scanning electron microscopy, Fourier transform infrared spectrometry and dynamic light scattering, Ag-EPS NPs were produced in both conditions and contained also Fe. The production yield of high-Fe/Ag-EPS NPs was 12 times higher than the production yield of low-Fe/Ag-EPS NPs, confirming the stimulatory effect of iron. However, relative Ag content and Ag+ ion release were higher in low-Fe/Ag-EPS NPs than in high-Fe/Ag-EPS NPs, as revealed by emission-excitation spectra by luminescent spectrometry using a novel ad hoc established phycoerythrin fluorescence-based assay. Interestingly, high and low-Fe/Ag-EPS NPs showed different and growth medium-dependent minimal inhibitory concentrations against Staphylococcus aureus ATCC 29213 and Pseudomonas aeruginosa ATCC 15442. In addition, low-Fe/Ag-EPS NPs exert inhibition of staphylococcal and pseudomonal biofilm formation, while high-Fe/Ag-EPS NPs inhibits staphylococcal biofilm formation only. Altogether, these results, highlighting the different capability of Ag+ release, support the idea that Fe/Ag-EPS NPs produced by K. oxytoca DSM 29614 can be considered as promising candidates in the development of specific antibacterial and anti-biofilm agents.Key points • Klebsiella oxytoca DSM 29614 produces bimetal nanoparticles containing Fe and Ag.• Fe concentration in growth medium affects nanoparticle yield and composition.• Phycoerythrin fluorescence-based assay was developed to determine Ag+release.• Antimicrobial efficacy of bimetal nanoparticle parallels Ag+ions release.


Assuntos
Antibacterianos/farmacologia , Biofilmes/efeitos dos fármacos , Ferro/química , Nanopartículas Metálicas/química , Prata/química , Antibacterianos/química , Antibacterianos/metabolismo , Biofilmes/crescimento & desenvolvimento , Meios de Cultura/química , Ferro/análise , Ferro/metabolismo , Klebsiella oxytoca/metabolismo , Testes de Sensibilidade Microbiana , Ficoeritrina/química , Polissacarídeos Bacterianos/química , Polissacarídeos Bacterianos/metabolismo , Pseudomonas aeruginosa/efeitos dos fármacos , Prata/metabolismo , Prata/farmacologia , Staphylococcus aureus/efeitos dos fármacos
19.
Antibiotics (Basel) ; 9(4)2020 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-32325952

RESUMO

Frankincense essential oils from Boswellia sacra have been commonly used to treat microbial infections from as early as the 11th century. The main feature of the plant is its gum resin, from which it is possible to obtain essential oils. In the present study, we focused on the comparative study of the oils extracted from the resins of three different Boswellia sacra cultivars (Najdi, Sahli and Houjri). From each of frankincense resin three successive essential oil samples (Grade 1, Grade 2, Grade 3) were obtained. Houjri gum resin gave the lowest percentage (5%) of total essential oil content but showed the maximum number of volatile components in all three grades. Najdi Grade 2 essential oil showed a minimum inhibitory concentration (MIC) of 52 mg/mL toward relevant pathogens Staphylococcus aureus and Pseudomonas aeruginosa, and samples from Grade 2 of Sahily and Houjiri were particularly active against a dermatological strain Propionibacterium acnes, displaying MIC values of 0.264 and 0.66 mg/mL, respectively. Data obtained from in vitro studies showed that all essential oils had a significant antifungal effect against Candida albicans and Malassezia furfur, showing MIC values ranging from 54.56 to 0.246 mg/mL. This work aims to increase the number of substances available in the fight against pathogens and to combat the phenomenon of antibiotic resistance, encouraging the use of alternative resources, especially in non-clinical settings (farms, food processing, etc.).

20.
J Med Chem ; 63(15): 7923-7956, 2020 08 13.
Artigo em Inglês | MEDLINE | ID: mdl-32208685

RESUMO

Thiazoles, their benzofused systems, and thiazolidinone derivatives are widely recognized as nuclei of great value for obtaining molecules with various biological activities, including analgesic, anti-inflammatory, anti-HIV, antidiabetic, antitumor, and antimicrobial. In particular, in the past decade, many compounds bearing these heterocycles have been studied for their promising antibacterial properties due to their action on different microbial targets. Here we assess the recent development of this class of compounds to address mechanisms underlying antibiotic resistance at both bacterial-cell and community levels (biofilms). We also explore the SAR and the prospective clinical application of thiazole and its benzofused derivatives, which act as inhibitors of mechanisms underlying antibiotic resistance in the treatment of severe drug-resistant infections. In addition, we examined all bacterial targets involved in their antimicrobial activity reporting, when described, their spontaneous frequencies of resistance.


Assuntos
Antibacterianos/química , Benzeno/química , Resistência Microbiana a Medicamentos/efeitos dos fármacos , Tiazóis/química , Tiazolidinas/química , Animais , Antibacterianos/farmacologia , Benzeno/farmacologia , Biofilmes/efeitos dos fármacos , Biofilmes/crescimento & desenvolvimento , Resistência Microbiana a Medicamentos/fisiologia , Humanos , Testes de Sensibilidade Microbiana/métodos , Relação Estrutura-Atividade , Tiazóis/farmacologia , Tiazolidinas/farmacologia
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