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1.
Molecules ; 26(11)2021 Jun 02.
Artigo em Inglês | MEDLINE | ID: mdl-34199336

RESUMO

The natural compound ravenelin was isolated from the biomass extracts of Exserohilum rostratum fungus, and its antimicrobial, antiplasmodial, and trypanocidal activities were evaluated. Ravenelin was isolated by column chromatography and HPLC and identified by NMR and MS. The susceptibility of Gram-positive and Gram-negative bacteria strains to ravenelin was determined by microbroth dilution assay. Cytotoxicity was evaluated in hepatocarcinoma cells (HepG2) and BALB/c peritoneal macrophages by using MTT. SYBR Green I-based assay was used in the asexual stages of Plasmodium falciparum. Trypanocidal activity was tested against the epimastigote and intracellular amastigote forms of Trypanosoma cruzi. Ravenelin was active against Gram-positive bacteria strains, with emphasis on Bacillus subtilis (MIC value of 7.5 µM). Ravenelin's antiparasitic activities were assessed against both the epimastigote (IC50 value of 5 ± 1 µM) and the intracellular amastigote forms of T. cruzi (IC50 value of 9 ± 2 µM), as well as against P. falciparum (IC50 value of 3.4 ± 0.4 µM). Ravenelin showed low cytotoxic effects on both HepG2 (CC50 > 50 µM) and peritoneal macrophage (CC50 = 185 ± 1 µM) cells with attractive selectivity for the parasites (SI values > 15). These findings indicate that ravenelin is a natural compound with both antibacterial and antiparasitic activities, and considerable selectivity indexes. Therefore, ravenelin is an attractive candidate for hit-to-lead development.


Assuntos
Antibacterianos/farmacologia , Antiprotozoários/farmacologia , Ascomicetos/química , Macrófagos Peritoneais/citologia , Xantonas/farmacologia , Animais , Antibacterianos/química , Antiprotozoários/química , Produtos Biológicos/química , Produtos Biológicos/farmacologia , Biomassa , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Cromatografia Líquida de Alta Pressão , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Positivas/efeitos dos fármacos , Células Hep G2 , Humanos , Macrófagos Peritoneais/efeitos dos fármacos , Macrófagos Peritoneais/parasitologia , Espectroscopia de Ressonância Magnética , Camundongos , Camundongos Endogâmicos BALB C , Testes de Sensibilidade Microbiana , Estrutura Molecular , Plasmodium falciparum/efeitos dos fármacos , Trypanosoma cruzi/efeitos dos fármacos , Xantonas/química
2.
Molecules ; 26(12)2021 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-34205312

RESUMO

In the current study, in vitro antimicrobial and antioxidant activities and in vivo anti-inflammatory and analgesic activities of Scutellaria edelbergii Rech. f. (crude extract and subfractions, i.e., n-hexane, ethyl acetate (EtOAc), chloroform, n-butanol (n-BuOH) and aqueous) were explored. Initially, extraction and fractionation of the selected medicinal plant were carried out, followed by phytochemical qualitative tests, which were mostly positive for all the extracts. EtOAc fraction possessed a significant amount of phenolic (79.2 ± 0.30 mg GAE/g) and flavonoid (84.0 ± 0.39 mg QE/g) content. The EtOAc fraction of S. edelbergii exhibited appreciable antibacterial activity against Gram-negative (Escherichia coli and Klebsiella pneumoniae) strains and significant zones of inhibition were observed against Gram-positive bacterial strains (Bacillus subtilis and Staphylococcus aureus). However, it was found inactive against Candida Albicans and Fusarium oxysporum fungal strains. The chloroform fraction was the most effective with an IC50 value of 172 and 74 µg/mL against DPPH (1,1-Diphenyl-2-picryl-hydrazyl) and ABTS assays, in comparison with standard ascorbic acid 59 and 63 µg/mL, respectively. Moreover, the EtOAc fraction displayed significant in vivo anti-inflammatory activity (54%) using carrageenan-induced assay and significant (55%) in vivo analgesic activity using acetic acid-induced writing assay. In addition, nine known compounds, ursolic acid (UA), ovaul (OV), oleanolic acid (OA), ß-sitosterol (BS), micromeric acid (MA), taraxasterol acetate (TA), 5,3',4'-trihydroxy-7-methoxy flavone (FL-1), 5,7,4'-trihydroxy-6,3'-dimiethoxyflavone (FL-2) and 7-methoxy catechin (FL-3), were isolated from methanolic extract of S. edelbergii. These constituents have never been obtained from this source. The structures of all the isolated constituents were elucidated by spectroscopic means. In conclusion, the EtOAc fraction and all other fractions of S. edelbergii, in general, displayed a significant role as antibacterial, free radical scavenger, anti-inflammatory and analgesic agents which may be due to the presence of these constituents and other flavonoids.


Assuntos
Extratos Vegetais/farmacologia , Scutellaria/química , Antibacterianos/química , Antibacterianos/farmacologia , Anti-Inflamatórios/farmacologia , Antifúngicos/farmacologia , Antioxidantes/farmacologia , Pesquisa Biomédica/métodos , Flavonoides/farmacologia , Fungos/efeitos dos fármacos , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Positivas/efeitos dos fármacos , Fenóis/farmacologia , Compostos Fitoquímicos/farmacologia , Plantas Medicinais/química
3.
Molecules ; 26(10)2021 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-34065282

RESUMO

The incidence of antibiotic resistance in pathogenic bacteria has become an alarming clinical and social problem. Therefore, the demand for alternative antimicrobial compounds has increased. In this study, a chemical profile of honey bee (Apis mellifera L.) venom (HBV) has been determined by HPLC and FTIR-ATR spectroscopy, and tested for antibacterial activity, as well as efficiency with regard to conventional antibiotics. The investigated HBV was of high quality with melittin and total protein contents of 70.10 ± 7.01%, and 84.44 ± 3.12 g/100 g, respectively. The purity of HBV was confirmed by FTIR-ATR spectral profiling, which revealed a unique pattern of absorption bands that are characteristic of its major fractions. In addition, HBV showed a broad spectrum of activity against all three tested biomasses of potentially pathogenic Gram-positive and Gram-negative bacteria with MIC values ranging between 12.5 and 200 µg/mL, and MBC between 12.5 and 400 µg/mL. When compared to conventional antibiotics, HBV (400 µg) showed up to 27.8% efficiency of tetracycline (30 µg), 52.2% erythromycin (15 µg), 21.2% ciprofloxacin (5 µg), and 34.6% of ampicillin-sulbactam (20 µg). The overall results demonstrate the therapeutic potential of the analyzed HBV.


Assuntos
Anti-Infecciosos/farmacologia , Venenos de Abelha/química , Venenos de Abelha/farmacologia , Animais , Abelhas , Cromatografia Líquida de Alta Pressão/métodos , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Positivas/efeitos dos fármacos , Humanos , Testes de Sensibilidade Microbiana , Espectroscopia de Infravermelho com Transformada de Fourier/métodos
4.
Toxins (Basel) ; 13(5)2021 05 11.
Artigo em Inglês | MEDLINE | ID: mdl-34064808

RESUMO

Scorpion venoms are rich resources of antimicrobial peptides (AMPs). While the short-chain noncysteine-containing AMPs have attracted much attention as templates for drug development, the antimicrobial potential of long-chain noncysteine-containing AMPs has been largely overlooked. Here, by using the online HeliQuest server, we designed and analyzed a series of 14-residue fragments of Smp43, a 43-residue long-chain noncysteine-containing AMP identified from the venom of Scorpio maurus palmatus. We found that Smp43(1-14) shows high antimicrobial activity against both Gram-positive and Gram-negative bacteria and is nontoxic to mammalian cells at the antimicrobial dosage. Sequence alignments showed that the designed Smp43(1-14) displays a unique primary structure that is different from other natural short-chain noncysteine-containing AMPs from scorpions, such as Uy17, Uy192 and IsCT. Moreover, the peptide Smp43(1-14) caused concentration-dependent fluorescence increases in the bacteria for all of the tested dyes, propidium iodide, SYTOXTM Green and DiSC3-5, suggesting that the peptide may kill the bacteria through the formation of pore structures in the plasma membrane. Taken together, our work sheds light on a new avenue for the design of novel short-chain noncysteine-containing AMPs and provides a good peptide template with a unique sequence for the development of novel drugs for use against bacterial infectious diseases.


Assuntos
Antibacterianos/farmacologia , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Positivas/efeitos dos fármacos , Proteínas Citotóxicas Formadoras de Poros/farmacologia , Venenos de Escorpião/química , Animais , Antibacterianos/isolamento & purificação , Membrana Celular/metabolismo , Proteínas Citotóxicas Formadoras de Poros/isolamento & purificação , Conformação Proteica em alfa-Hélice , Escorpiões
5.
Biomolecules ; 11(5)2021 05 17.
Artigo em Inglês | MEDLINE | ID: covidwho-1234665

RESUMO

Cm-p5 is a snail-derived antimicrobial peptide, which demonstrated antifungal activity against the pathogenic strains of Candida albicans. Previously we synthetized a cyclic monomer as well as a parallel and an antiparallel dimer of Cm-p5 with improved antifungal activity. Considering the alarming increase of microbial resistance to conventional antibiotics, here we evaluated the antimicrobial activity of these derivatives against multiresistant and problematic bacteria and against important viral agents. The three peptides showed a moderate activity against Pseudomonas aeruginosa, Klebsiella pneumoniae Extended Spectrum ß-Lactamase (ESBL), and Streptococcus agalactiae, with MIC values > 100 µg/mL. They exerted a considerable activity with MIC values between 25-50 µg/mL against Acinetobacter baumanii and Enterococcus faecium. In addition, the two dimers showed a moderate activity against Pseudomonas aeruginosa PA14. The three Cm-p5 derivatives inhibited a virulent extracellular strain of Mycobacterium tuberculosis, in a dose-dependent manner. Moreover, they inhibited Herpes Simplex Virus 2 (HSV-2) infection in a concentration-dependent manner, but had no effect on infection by the Zika Virus (ZIKV) or pseudoparticles of Severe Acute Respiratory Syndrome Corona Virus 2 (SARS-CoV-2). At concentrations of >100 µg/mL, the three new Cm-p5 derivatives showed toxicity on different eukaryotic cells tested. Considering a certain cell toxicity but a potential interesting activity against the multiresistant strains of bacteria and HSV-2, our compounds require future structural optimization.


Assuntos
Antibacterianos/farmacologia , Peptídeos Catiônicos Antimicrobianos/química , Antivirais/farmacologia , Farmacorresistência Bacteriana Múltipla/efeitos dos fármacos , Herpesvirus Humano 2/efeitos dos fármacos , Sequência de Aminoácidos , Animais , Antibacterianos/química , Peptídeos Catiônicos Antimicrobianos/farmacologia , Antivirais/química , Candida albicans/efeitos dos fármacos , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Dimerização , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Positivas/efeitos dos fármacos , Humanos , Testes de Sensibilidade Microbiana , SARS-CoV-2/efeitos dos fármacos
7.
Sci Rep ; 11(1): 12410, 2021 06 14.
Artigo em Inglês | MEDLINE | ID: covidwho-1268005

RESUMO

In situ generation of antibacterial and antiviral agents by harnessing the catalytic activity of enzymes on surfaces provides an effective eco-friendly approach for disinfection. The perhydrolase (AcT) from Mycobacterium smegmatis catalyzes the perhydrolysis of acetate esters to generate the potent disinfectant, peracetic acid (PAA). In the presence of AcT and its two substrates, propylene glycol diacetate and H2O2, sufficient and continuous PAA is generated over an extended time to kill a wide range of bacteria with the enzyme dissolved in aqueous buffer. For extended self-disinfection, however, active and stable AcT bound onto or incorporated into a surface coating is necessary. In the current study, an active, stable and reusable AcT-based coating was developed by incorporating AcT into a polydopamine (PDA) matrix in a single step, thereby forming a biocatalytic composite onto a variety of surfaces. The resulting AcT-PDA composite coatings on glass, metal and epoxy surfaces yielded up to 7-log reduction of Gram-positive and Gram-negative bacteria when in contact with the biocatalytic coating. This composite coating also possessed potent antiviral activity, and dramatically reduced the infectivity of a SARS-CoV-2 pseudovirus within minutes. The single-step approach enables rapid and facile fabrication of enzyme-based disinfectant composite coatings with high activity and stability, which enables reuse following surface washing. As a result, this enzyme-polymer composite technique may serve as a general strategy for preparing antibacterial and antiviral surfaces for applications in health care and common infrastructure safety, such as in schools, the workplace, transportation, etc.


Assuntos
Antibacterianos/química , Antivirais/química , Proteínas de Bactérias/química , Hidrolases/química , Indóis/química , Polímeros/química , Antibacterianos/metabolismo , Antibacterianos/farmacologia , Antivirais/metabolismo , Antivirais/farmacologia , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , COVID-19/patologia , COVID-19/virologia , Materiais Revestidos Biocompatíveis/química , Materiais Revestidos Biocompatíveis/metabolismo , Materiais Revestidos Biocompatíveis/farmacologia , Estabilidade de Medicamentos , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Positivas/efeitos dos fármacos , Humanos , Hidrolases/genética , Hidrolases/metabolismo , Cinética , Mycobacterium smegmatis/enzimologia , Ácido Peracético/metabolismo , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/química , Proteínas Recombinantes/isolamento & purificação , SARS-CoV-2/efeitos dos fármacos
9.
Biomolecules ; 11(5)2021 05 17.
Artigo em Inglês | MEDLINE | ID: mdl-34067685

RESUMO

Cm-p5 is a snail-derived antimicrobial peptide, which demonstrated antifungal activity against the pathogenic strains of Candida albicans. Previously we synthetized a cyclic monomer as well as a parallel and an antiparallel dimer of Cm-p5 with improved antifungal activity. Considering the alarming increase of microbial resistance to conventional antibiotics, here we evaluated the antimicrobial activity of these derivatives against multiresistant and problematic bacteria and against important viral agents. The three peptides showed a moderate activity against Pseudomonas aeruginosa, Klebsiella pneumoniae Extended Spectrum ß-Lactamase (ESBL), and Streptococcus agalactiae, with MIC values > 100 µg/mL. They exerted a considerable activity with MIC values between 25-50 µg/mL against Acinetobacter baumanii and Enterococcus faecium. In addition, the two dimers showed a moderate activity against Pseudomonas aeruginosa PA14. The three Cm-p5 derivatives inhibited a virulent extracellular strain of Mycobacterium tuberculosis, in a dose-dependent manner. Moreover, they inhibited Herpes Simplex Virus 2 (HSV-2) infection in a concentration-dependent manner, but had no effect on infection by the Zika Virus (ZIKV) or pseudoparticles of Severe Acute Respiratory Syndrome Corona Virus 2 (SARS-CoV-2). At concentrations of >100 µg/mL, the three new Cm-p5 derivatives showed toxicity on different eukaryotic cells tested. Considering a certain cell toxicity but a potential interesting activity against the multiresistant strains of bacteria and HSV-2, our compounds require future structural optimization.


Assuntos
Antibacterianos/farmacologia , Peptídeos Catiônicos Antimicrobianos/química , Antivirais/farmacologia , Farmacorresistência Bacteriana Múltipla/efeitos dos fármacos , Herpesvirus Humano 2/efeitos dos fármacos , Sequência de Aminoácidos , Animais , Antibacterianos/química , Peptídeos Catiônicos Antimicrobianos/farmacologia , Antivirais/química , Candida albicans/efeitos dos fármacos , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Dimerização , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Positivas/efeitos dos fármacos , Humanos , Testes de Sensibilidade Microbiana , SARS-CoV-2/efeitos dos fármacos
10.
Int J Mol Sci ; 22(11)2021 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-34073939

RESUMO

An amphipathic α-helical peptide, Hp1404, was isolated from the venomous gland of the scorpion Heterometrus petersii. Hp1404 exhibits antimicrobial activity against methicillin-resistant Staphylococcus aureus but is cytotoxic. In this study, we designed antimicrobial peptides by substituting amino acids at the 14 C-terminal residues of Hp1404 to reduce toxicity and improve antibacterial activity. The analog peptides, which had an amphipathic α-helical structure, were active against gram-positive and gram-negative bacteria, particularly multidrug-resistant Acinetobacter baumannii, and showed lower cytotoxicity than Hp1404. N-phenyl-1-naphthylamine uptake and DisC3-5 assays demonstrated that the peptides kill bacteria by effectively permeating the outer and cytoplasmic membranes. Additionally, the analog peptides inhibited biofilm formation largely than Hp1404 at low concentrations. These results suggest that the analog peptides of Hp1404 can be used as therapeutic agents against A. baumannii infection.


Assuntos
Acinetobacter baumannii/efeitos dos fármacos , Antibacterianos/farmacologia , Peptídeos Catiônicos Antimicrobianos/genética , Peptídeos Catiônicos Antimicrobianos/farmacologia , Farmacorresistência Bacteriana Múltipla/efeitos dos fármacos , Escorpiões/química , 1-Naftilamina/análogos & derivados , 1-Naftilamina/metabolismo , Animais , Peptídeos Catiônicos Antimicrobianos/efeitos adversos , Peptídeos Catiônicos Antimicrobianos/química , Benzotiazóis/metabolismo , Biofilmes/efeitos dos fármacos , Carbocianinas/metabolismo , Sobrevivência Celular/efeitos dos fármacos , Dicroísmo Circular , Escherichia coli/efeitos dos fármacos , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Positivas/efeitos dos fármacos , Hemólise/efeitos dos fármacos , Listeria monocytogenes/efeitos dos fármacos , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Conformação Proteica em alfa-Hélice , Pseudomonas aeruginosa/efeitos dos fármacos , Salmonella/efeitos dos fármacos
11.
J Med Microbiol ; 70(6)2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-34165418

RESUMO

Introduction. Colistin is one of the last-resort antibiotics for treating multidrug-resistant (MDR) or extensively drug-resistant (XDR) lactose non-fermenting Gram-negative bacteria such as Pseudomonas aeruginosa and Acinetobacter baumannii.Gap Statement. As the rate of colistin resistance is steadily rising, there is a need for rapid and accurate antimicrobial susceptibility testing methods for colistin. The Rapid ResaPolymyxin Acinetobacter/Pseudomonas NP test has recently been developed for rapid detection of colistin resistance in P. aeruginosa and A. baumannii.Aim. The present study aimed to evaluate the performance of the Rapid ResaPolymyxin Acinetobacter/Pseudomonas NP test in comparison with the reference broth microdilution (BMD) method.Methodology. The Rapid ResaPolymyxin Acinetobacter/Pseudomonas NP test was performed using a total of 135 P. aeruginosa (17 colistin-resistant and 118 colistin-susceptible) and 66 A. baumannii isolates (32 colistin-resistant and 34 colistin-susceptible), in comparison with the reference BMD method.Results. The categorical agreement of the Rapid ResaPolymyxin Acinetobacter/Pseudomonas NP test with the reference BMD method was 97.5 % with a major error rate of 0 % (0/152) and a very major error (VME) rate of 10.2 %. The VME rate was higher (23.5 %) when calculated separately for P. aeruginosa isolates. The overall sensitivity and specificity were 89.8 and 100 %, respectively.Conclusion. The Rapid ResaPolymyxin Acinetobacter/Pseudomonas NP test performed better for A. baumannii than for P. aeruginosa.


Assuntos
Antibacterianos/farmacologia , Colistina/farmacologia , Bactérias Gram-Negativas/efeitos dos fármacos , Testes de Sensibilidade Microbiana/normas , Acinetobacter baumannii/efeitos dos fármacos , Resistência a Múltiplos Medicamentos , Humanos , Indicadores e Reagentes/química , Oxazinas/química , Polimixinas/química , Pseudomonas aeruginosa/efeitos dos fármacos , Xantenos/química
12.
Int J Food Microbiol ; 352: 109267, 2021 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-34102464

RESUMO

The use of bacteriocins is a promising alternative to improve food security through the biocontrol of food pathogens and spoilage microorganisms. Gram-negative produced microcin J25(G12Y), known as (MccJ25(G12Y)) is a variant of the well-studied and characterized antimicrobial peptide, microcin J25 (MccJ25). In the present work, we explored the activity of this microcin against Gram-negative bacteria linked to foodborne diseases. We evaluated the in vitro antimicrobial activity of MccJ25(G12Y) in solid medium against a collection of pathogenic and food-altering strains and studied its activity and stability in meat and dairy food systems. We show that MccJ25(G12Y) exhibited the same in vitro antimicrobial spectrum as its parental microcin (MccJ25) against different Gram-negative foodborne pathogens and spoilage strains. We highlight that low concentrations of MccJ25(G12Y) between 0.45 and 29.4 µM were able to inhibit a substantial number of pathogens, including Salmonella, Escherichia, Shigella and Enterobacter genus. We also demonstrate the antimicrobial effectiveness of the peptide against Escherichia coli O157:H7 NCTC 12900, Enterobacter cloacae CECT 194, and Salmonella enterica CECT 4396 in fish and beef burgers and yogurt. MccJ25(G12Y) was added or not to food matrices inoculated with the foodborne pathogens at 105 CFU/g or mL. Afterward, food products were stored at 4 °C and selective media for the specific enumeration were used to determine the antimicrobial susceptibility of each pathogen to MccJ25(G12Y). The viability of the three pathogens was significantly reduced in the different food biological environments. In yogurt, the peptide decreased E. coli numbers on day 5 by about 4 log 10 CFU/mL as compared to non-treated samples. For S. enterica and E. cloacae no viable cells were detected at the end of the treatment. Adding MccJ25(G12Y) to fish burgers decreased E. cloacae numbers during storage 2 log10 CFU/g on the first day, reaching a difference of about 5 log 10 CFU/g after 10 days compared to non-treated control. Finally, the peptide decreased E. coli O157:H7 numbers on the beef burgers samples during storage on day 10 by about 3 log 10 CFU/g as compared to non-treated samples. The stability analysis demonstrated that MccJ25(G12Y) is capable of remaining active in these food matrices for a considerable time during the storage at refrigeration temperatures. These results reinforce the studies on the potential applicability of this microcin as a biopreservative in the food industry.


Assuntos
Bacteriocinas/farmacologia , Manipulação de Alimentos/métodos , Microbiologia de Alimentos , Bactérias Gram-Negativas/efeitos dos fármacos , Animais , Antibacterianos/farmacologia , Contagem de Colônia Microbiana , Escherichia coli O157/efeitos dos fármacos , Doenças Transmitidas por Alimentos/microbiologia , Doenças Transmitidas por Alimentos/prevenção & controle , Salmonella/efeitos dos fármacos
13.
Int J Food Microbiol ; 352: 109281, 2021 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-34126526

RESUMO

Food-borne pathogenic bacteria are dispersed throughout the entire chain of the food industry. However, many food preservatives are limited by poor biocompatibility such as cumulative poisoning. The antimicrobial peptide is increasingly regarded as a promising preservative in food research due to its high bioactivity and low cytotoxicity. In this study, thirteen peptides were designed, synthesized, and screened for application as food preservatives. One of them, termed zp65, whose sequence is GIOAOIIIOIOO-NH2, demonstrated potent bactericidal effect against common Gram-negative strains including enterohemorrhagic Escherichia coli, Salmonella, and Citrobacter freundii. Encouragingly, zp65 showed negligible cytotoxicity to both mammalian cells and Galleria mellonella larvae. Peptide zp65 was prone to form α-helix structure in amphiphilic environments, facilitating its affinity with bacterial membrane. Furthermore, the proteolytic stability of zp65 was much higher than its derivatives consisting of totally natural amino acids. Isothermal titration calorimetry indicated that zp65 has a strong binding affinity to lipopolysaccharide with Kd = 1.3 µM, suggesting its possible action target on the bacterial envelope. Mechanistic studies revealed that this peptide also influenced the membrane potential of E.coli O157:H7 (O157) in a dose-dependent manner. Surprisingly, peptide zp65 did not induce disruption of membrane permeability even at a higher concentration of 4-fold minimal inhibitory concentration. By employing confocal microscopy, peptide zp65 labeled by fluorescein isothiocyanate mainly aggregated on the bacterial membrane. These results suggested that the bactericidal mode of action of zp65 is likely attributed to depolarization of the cell membrane. The minced lean beef experiment indicated that the maximum reduction of O157 reached 1.46 log colony-forming unit (CFU) per gram on day 1 after zp65 treatment at the dosage of 40 µg/g. Compared with the untreated cooked beef sample, the CFU of the zp65-treated group remained at a much lower level after 10-day storage. Subsequently, treatment with zp65 at concentrations above 32 µM also significantly reduced O157 viable counts in fresh tomato juice. And the zp65 treatment could rescue about 40% of Galleria mellonella larvae injected with O157-contaminated tomato juice. The peptide zp65 exhibits great potential and deserves further study as a candidate for food preservative.


Assuntos
Escherichia coli O157/efeitos dos fármacos , Microbiologia de Alimentos , Conservantes de Alimentos/farmacologia , Bactérias Gram-Negativas/efeitos dos fármacos , Proteínas Citotóxicas Formadoras de Poros/farmacologia , Animais , Antibacterianos/farmacologia , Bovinos , Contagem de Colônia Microbiana , Larva/efeitos dos fármacos , Potenciais da Membrana/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Mariposas/efeitos dos fármacos , Ornitina/química , Carne Vermelha/microbiologia
14.
Sci Rep ; 11(1): 12410, 2021 06 14.
Artigo em Inglês | MEDLINE | ID: mdl-34127732

RESUMO

In situ generation of antibacterial and antiviral agents by harnessing the catalytic activity of enzymes on surfaces provides an effective eco-friendly approach for disinfection. The perhydrolase (AcT) from Mycobacterium smegmatis catalyzes the perhydrolysis of acetate esters to generate the potent disinfectant, peracetic acid (PAA). In the presence of AcT and its two substrates, propylene glycol diacetate and H2O2, sufficient and continuous PAA is generated over an extended time to kill a wide range of bacteria with the enzyme dissolved in aqueous buffer. For extended self-disinfection, however, active and stable AcT bound onto or incorporated into a surface coating is necessary. In the current study, an active, stable and reusable AcT-based coating was developed by incorporating AcT into a polydopamine (PDA) matrix in a single step, thereby forming a biocatalytic composite onto a variety of surfaces. The resulting AcT-PDA composite coatings on glass, metal and epoxy surfaces yielded up to 7-log reduction of Gram-positive and Gram-negative bacteria when in contact with the biocatalytic coating. This composite coating also possessed potent antiviral activity, and dramatically reduced the infectivity of a SARS-CoV-2 pseudovirus within minutes. The single-step approach enables rapid and facile fabrication of enzyme-based disinfectant composite coatings with high activity and stability, which enables reuse following surface washing. As a result, this enzyme-polymer composite technique may serve as a general strategy for preparing antibacterial and antiviral surfaces for applications in health care and common infrastructure safety, such as in schools, the workplace, transportation, etc.


Assuntos
Antibacterianos/química , Antivirais/química , Proteínas de Bactérias/química , Hidrolases/química , Indóis/química , Polímeros/química , Antibacterianos/metabolismo , Antibacterianos/farmacologia , Antivirais/metabolismo , Antivirais/farmacologia , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , COVID-19/patologia , COVID-19/virologia , Materiais Revestidos Biocompatíveis/química , Materiais Revestidos Biocompatíveis/metabolismo , Materiais Revestidos Biocompatíveis/farmacologia , Estabilidade de Medicamentos , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Positivas/efeitos dos fármacos , Humanos , Hidrolases/genética , Hidrolases/metabolismo , Cinética , Mycobacterium smegmatis/enzimologia , Ácido Peracético/metabolismo , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/química , Proteínas Recombinantes/isolamento & purificação , SARS-CoV-2/efeitos dos fármacos
15.
Bioorg Chem ; 112: 104925, 2021 07.
Artigo em Inglês | MEDLINE | ID: covidwho-1198631

RESUMO

Antibiotic resistance and emerging viral pandemics have posed an urgent need for new anti-infective drugs. By screening our microbial extract library against the main protease of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and the notorious ESKAPE pathogens, an active fraction was identified and purified, leading to an initial isolation of adipostatins A (1) and B (2). In order to diversify the chemical structures of adipostatins toward enhanced biological activities, a type III polyketide synthase was identified from the native producer, Streptomyces davawensis DSM101723, and was subsequently expressed in an E. coli host, resulting in the isolation of nine additional adipostatins 3-11, including two new analogs (9 and 11). The structures of 1-11 were established by HRMS, NMR, and chemical derivatization, including using a microgram-scale meta-chloroperoxybenzoic acid epoxidation-MS/MS analysis to unambiguously determine the double bond position in the alkyl chain. The present study discovered SARS-CoV-2 main protease inhibitory activity for the class of adipostatins for the first time. Several of the adipostatins isolated also exhibited antimicrobial activity against selected ESKAPE pathogens.


Assuntos
Aciltransferases/metabolismo , Anti-Infecciosos/química , Proteínas de Bactérias/metabolismo , Resorcinóis/química , Aciltransferases/antagonistas & inibidores , Aciltransferases/classificação , Aciltransferases/genética , Anti-Infecciosos/isolamento & purificação , Anti-Infecciosos/metabolismo , Anti-Infecciosos/farmacologia , Proteínas de Bactérias/antagonistas & inibidores , Proteínas de Bactérias/classificação , Proteínas de Bactérias/genética , COVID-19/patologia , COVID-19/virologia , Proteases 3C de Coronavírus/antagonistas & inibidores , Proteases 3C de Coronavírus/metabolismo , Avaliação Pré-Clínica de Medicamentos , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Positivas/efeitos dos fármacos , Humanos , Concentração Inibidora 50 , Espectroscopia de Ressonância Magnética , Testes de Sensibilidade Microbiana , Conformação Molecular , Filogenia , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/química , Proteínas Recombinantes/isolamento & purificação , Resorcinóis/isolamento & purificação , Resorcinóis/metabolismo , Resorcinóis/farmacologia , SARS-CoV-2/isolamento & purificação , SARS-CoV-2/metabolismo , Streptomyces/enzimologia , Espectrometria de Massas em Tandem
16.
Nat Commun ; 12(1): 2560, 2021 05 07.
Artigo em Inglês | MEDLINE | ID: mdl-33963193

RESUMO

The commensal fungus Candida albicans often causes life-threatening infections in patients who are immunocompromised with high mortality. A prominent but poorly understood risk factor for the C. albicans commensal‒pathogen transition is the use of broad-spectrum antibiotics. Here, we report that ß-lactam antibiotics cause bacteria to release significant quantities of peptidoglycan fragments that potently induce the invasive hyphal growth of C. albicans. We identify several active peptidoglycan subunits, including tracheal cytotoxin, a molecule produced by many Gram-negative bacteria, and fragments purified from the cell wall of Gram-positive Staphylococcus aureus. Feeding mice with ß-lactam antibiotics causes a peptidoglycan storm that transforms the gut from a niche usually restraining C. albicans in the commensal state to promoting invasive growth, leading to systemic dissemination. Our findings reveal a mechanism underlying a significant risk factor for C. albicans infection, which could inform clinicians regarding future antibiotic selection to minimize this deadly disease incidence.


Assuntos
Candida albicans/patogenicidade , Candidíase/microbiologia , Microbioma Gastrointestinal/efeitos dos fármacos , Peptidoglicano/toxicidade , Infecções Estafilocócicas/tratamento farmacológico , Staphylococcus aureus/efeitos dos fármacos , beta-Lactamas/efeitos adversos , Animais , Antibacterianos/efeitos adversos , Candida albicans/crescimento & desenvolvimento , Candidíase/complicações , Candidíase/tratamento farmacológico , Candidíase/patologia , Parede Celular/química , Parede Celular/efeitos dos fármacos , Cromatografia Líquida , Feminino , Bactérias Gram-Negativas/química , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Negativas/metabolismo , Humanos , Hifas/crescimento & desenvolvimento , Hifas/patogenicidade , Espectrometria de Massas , Camundongos , Camundongos Endogâmicos BALB C , Peptidoglicano/química , Infecções Estafilocócicas/complicações , Staphylococcus aureus/química , Staphylococcus aureus/metabolismo
17.
J Med Chem ; 64(11): 7630-7645, 2021 06 10.
Artigo em Inglês | MEDLINE | ID: mdl-34009979

RESUMO

A class of quinazolone thiazoles was identified as new structural scaffolds for potential antibacterial conquerors to tackle dreadful resistance. Some prepared compounds exhibited favorable bacteriostatic efficiencies on tested bacteria, and the most representative 5j featuring the 4-trifluoromethylphenyl group possessed superior performances against Escherichia coli and Pseudomonas aeruginosa to norfloxacin. Further studies revealed that 5j with inappreciable hemolysis could hinder the formation of bacterial biofilms and trigger reactive oxygen species generation, which could take responsibility for emerging low resistance. Subsequent paralleled exploration discovered that 5j not only disintegrated outer and inner membranes to induce leakage of cytoplasmic contents but also broke the metabolism by suppressing dehydrogenase. Meanwhile, derivative 5j could intercalate into DNA to exert powerful antibacterial properties. Moreover, compound 5j gave synergistic effects against some Gram-negative bacteria in combination with norfloxacin. These findings indicated that this novel structural type of quinazolone thiazoles showed therapeutic foreground in struggling with Gram-negative bacterial infections.


Assuntos
Antibacterianos/farmacologia , Azóis/química , Bactérias Gram-Negativas/efeitos dos fármacos , Tiazóis/química , Antibacterianos/química , Antibacterianos/metabolismo , Membrana Externa Bacteriana/efeitos dos fármacos , Membrana Externa Bacteriana/metabolismo , Sítios de Ligação , Ligação Competitiva , Biofilmes/efeitos dos fármacos , Cristalografia por Raios X , Desenho de Fármacos , Farmacorresistência Bacteriana/efeitos dos fármacos , Escherichia coli/fisiologia , Bactérias Gram-Positivas/efeitos dos fármacos , L-Lactato Desidrogenase/antagonistas & inibidores , L-Lactato Desidrogenase/metabolismo , Testes de Sensibilidade Microbiana , Conformação Molecular , Simulação de Acoplamento Molecular , Pseudomonas aeruginosa/fisiologia , Espécies Reativas de Oxigênio/metabolismo , Tiazóis/metabolismo , Tiazóis/farmacologia
18.
BMC Infect Dis ; 21(1): 444, 2021 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-34001022

RESUMO

BACKGROUND: To investigate the trends and correlation between antibacterial consumption and carbapenem resistance in Gram-negative bacteria from 2012 to 2019 in a tertiary-care teaching hospital in southern China. METHODS: This retrospective study included data from hospital-wide inpatients collected between January 2012 and December 2019. Data on antibacterial consumption were expressed as defined daily doses (DDDs)/1000 patient-days. Antibacterials were classified according to the Anatomical Therapeutic Chemical (ATC) classification system. The trends in antimicrobial usage and resistance were analyzed by linear regression, while Pearson correlation analysis was used for assessing correlations. RESULTS: An increasing trend in the annual consumption of tetracyclines, ß-lactam/ß-lactamase inhibitor (BL/BLI) combinations, and carbapenems was observed (P < 0.05). Carbapenem resistance in Acinetobacter baumannii (A. baumannii) significantly increased (P < 0.05) from 18% in 2012 to 60% in 2019. Moreover, significant positive correlations were found between resistance to carbapenems in A. baumannii (P < 0.05) and Escherichia coli (E. coli; P < 0.05) and consumption of carbapenems, while the resistance rate of A. baumannii to carbapenems was positively correlated with cephalosporin/ß-lactamase inhibitor (C/BLI) combinations (P < 0.01) and tetracyclines usage (P < 0.05). We also found that use of quinolones was positively correlated with the resistance rate of Burkholderia cepacia (B. cepacia) to carbapenems (P < 0.05), and increasing uses of carbapenems (P < 0.01) and penicillin/ß-Lactamase inhibitor (P/BLI) combinations (P < 0.01) were significantly correlated with reduced resistance of Enterobacter cloacae (E. cloacae) to carbapenems. CONCLUSION: These results revealed significant correlations between consumption of antibiotics and carbapenem resistance rates in Gram-negative bacteria. Implementing proper management strategies and reducing the unreasonable use of antibacterial drugs may be an effective measure to reduce the spread of carbapenem-resistant Gram-negative bacteria (CRGN), which should be confirmed by further studies.


Assuntos
Farmacorresistência Bacteriana , Bactérias Gram-Negativas/metabolismo , Infecções por Bactérias Gram-Negativas/diagnóstico , Acinetobacter baumannii/efeitos dos fármacos , Acinetobacter baumannii/isolamento & purificação , Acinetobacter baumannii/metabolismo , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Burkholderia cepacia/efeitos dos fármacos , Burkholderia cepacia/isolamento & purificação , Burkholderia cepacia/metabolismo , Carbapenêmicos/farmacologia , Carbapenêmicos/uso terapêutico , Cefalosporinas/metabolismo , China , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Negativas/isolamento & purificação , Infecções por Bactérias Gram-Negativas/tratamento farmacológico , Infecções por Bactérias Gram-Negativas/microbiologia , Humanos , Modelos Lineares , Testes de Sensibilidade Microbiana , Estudos Retrospectivos , Centros de Atenção Terciária , Tetraciclinas/metabolismo , Inibidores de beta-Lactamases/metabolismo
19.
Methods Mol Biol ; 2296: 59-75, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33977442

RESUMO

Extremophilic actinomycetes strains can survive extreme saline and alkaline environments and produce antimicrobial agents. In this chapter, we discuss laboratory methods that can be used to isolate and characterize actinomycetes strains capable of potentially producing novel antimicrobial agent(s) when cultured in conditions that mimic the environments from which they were isolated. Methods used to screen for antibacterial and antiviral activities from these producer strains, and microbiological and molecular approaches used to identify these strains are described. Here we describe three methods. Method 1 focuses on the strategy to select optimal conditions to synthesize and accumulate the antibiotics from the studied actinomycetes strains by preparing crude extracts. In Method 2, we describe the screening strategies used to test the actinomycetes strains against gram-negative and gram-positive bacteria, antifungal agents, multidrug-resistant pathogens (MDR), and viral pathogens. Thus, the specific techniques to test for MDR pathogens such as the disk diffusion assay and wells assay are outlined. We also describe the antiviral activity screening of the selected actinomycetes extracts in Method 2 of this chapter. Specifically, we concentrate on methods used to test for antiviral activities such as primary hemolytic, hemagglutination, neuraminidase, and specific virus-inhibitory activities. Finally, the Method 3 section reveals the microbiological techniques used to morphologically characterize the actinomycetes strains that depend on the culture medium utilized for growth. Additionally, the method used to perform a detailed characterization of the morphology that actinomycetes strains possess is specified by the protocol for sample preparation and visualization using the scanning electron microscopy (SEM). Finally, we summarize the molecular approaches used to characterize actinomycetes strains, focusing specifically on the PCR and sequencing techniques.


Assuntos
Actinobacteria/metabolismo , Anti-Infecciosos/metabolismo , Extremófilos/metabolismo , Anti-Infecciosos/farmacologia , Antivirais/metabolismo , Antivirais/farmacologia , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Positivas/efeitos dos fármacos
20.
Methods Mol Biol ; 2296: 143-149, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33977445

RESUMO

Screening extracts from the fermentation broth of a collection of actinomycetes can be performed conveniently on a microtiter plate format. Here we describe a method suited for the screening of antibacterial extracts or compounds against Gram-positive and Gram-negative aerobic, non-fastidious bacteria, Escherichia coli and Kocuria rhizophila. Both bacteria have been chosen to minimize the need for containment as they belong to risk group 1.


Assuntos
Actinobacteria/metabolismo , Antibacterianos/metabolismo , Antibacterianos/farmacologia , Fermentação/fisiologia , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Positivas/efeitos dos fármacos , Testes de Sensibilidade Microbiana/métodos
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