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1.
J Agric Food Chem ; 67(45): 12393-12401, 2019 Nov 13.
Artigo em Inglês | MEDLINE | ID: mdl-31596571

RESUMO

Accumulation of toxic copper in soil and development of copper-resistant pests are emerging challenges currently faced by the agricultural community worldwide. As an alternative, we have developed a ternary zinc chelate solution (TSOL) pesticide where zinc ions are the primary active ingredient. The material is composed of zinc, urea, and hydrogen peroxide. Urea was chosen as it is widely used as a plant fertilizer and can also bind to both zinc and hydrogen peroxide. No phytotoxicity was observed with TSOL on Meyer lemon (Citrus × meyeri) seedlings at a field spray rate of 800 µg/mL Zn metal concentration. Antimicrobial studies showed that TSOL exhibited improved killing efficacy against Escherichia coli and Xanthomonas alfalfae compared to Zn ions alone. Citrus canker field trials in a grapefruit (Chrysopelea paradisi) grove over three years showed that TSOL provided comparable disease protection to copper products at an equivalent or lower metal content.


Assuntos
Antibacterianos/química , Citrus/microbiologia , Peróxido de Hidrogênio/química , Doenças das Plantas/microbiologia , Ureia/química , Zinco/química , Zinco/farmacologia , Antibacterianos/farmacologia , Escherichia coli/efeitos dos fármacos , Escherichia coli/crescimento & desenvolvimento , Peróxido de Hidrogênio/farmacologia , Folhas de Planta/microbiologia , Ureia/farmacologia , Xanthomonas/efeitos dos fármacos , Xanthomonas/crescimento & desenvolvimento
2.
J Agric Food Chem ; 67(45): 12584-12589, 2019 Nov 13.
Artigo em Inglês | MEDLINE | ID: mdl-31640344

RESUMO

Lysozyme has emerged to be a promising alternative to traditional antibiotics to deal with the increasing antibiotic resistance of bacteria. However, its application is hampered by its inferior bactericidal activity against Gram-negative bacteria. To address this problem, a novel "enzyme-cascade fluorescent high-throughput screening (HTS) method" was designed and constructed based on detection of fluorescence resonance energy transfer (FRET) and enzyme-cascade reaction of lysozyme and protease. As a proof of concept, site-saturation mutagenesis libraries targeting at residues of the unstructured stretch at the N-terminus of Antheraea pernyi lysozyme were constructed and screened by the proposed HTS method. The isolated lysozyme variants proved to exhibit higher antibacterial activity against Escherichia coli K12, demonstrating the significance of this region for the bactericidal function of lysozyme. The presented cell-based fluorescent HTS method is a new tool for screening lysozyme variants with improved bactericidal efficacy against Gram-negative bacteria and for exploring the sequence-structure-function relationship of lysozyme.


Assuntos
Antibacterianos/química , Antibacterianos/farmacologia , Escherichia coli/efeitos dos fármacos , Transferência Ressonante de Energia de Fluorescência/métodos , Ensaios de Triagem em Larga Escala/métodos , Muramidase/química , Muramidase/farmacologia , Animais , Escherichia coli/crescimento & desenvolvimento , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Negativas/crescimento & desenvolvimento , Testes de Sensibilidade Microbiana , Mariposas/química , Mariposas/genética , Mariposas/metabolismo
3.
J Agric Food Chem ; 67(40): 11066-11076, 2019 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-31508948

RESUMO

The electrospinning of nanofibers (NFs) of cinnamaldehyde inclusion complexes (ICs) with two different hydroxypropylated cyclodextrins (CDs), hydroxypropyl-ß-cyclodextrin (HP-ß-CD) and hydroxypropyl-γ-cyclodextrin (HP-γ-CD), was successfully performed in order to produce cinnamaldehyde/CD-IC NFs without using an additional polymer matrix. The inclusion complexation between cinnamaldehyde and hydroxypropylated CDs was studied by computational molecular modeling, and the results suggested that HP-ß-CD and HP-γ-CD can be inclusion complexed with cinnamaldehyde at 1:1 and 2:1 (cinnamaldehyde/CD) molar ratios. Additionally, molecular modeling and phase solubility studies showed that water solubility of cinnamaldehyde dramatically increases with cyclodextrin inclusion complex (CD-IC) formation. The HP-ß-CD has shown slightly stronger binding with cinnamaldehyde when compared to HP-γ-CD for cinnamaldehyde/CD-IC. Although cinnamaldehyde is a highly volatile compound, it was effectively preserved with high loading by the cinnamaldehyde/CD-IC NFs. It was also observed that cinnamaldehyde has shown much higher temperature stability in cinnamaldehyde/CD-IC NFs compared to uncomplexed cinnamaldehyde because of the inclusion complexation state of cinnamaldehyde within the hydroxypropylated CD cavity. Moreover, cinnamaldehyde still has kept its antibacterial activity in cinnamaldehyde/CD-IC NF samples when tested against Escherichia coli. In addition, cinnamaldehyde/CD-IC NF mats were fast-dissolving in water, even though pure cinnamaldehyde has a water-insoluble nature. In brief, self-standing nanofibrous mats of electrospun cinnamaldehyde/CD-IC NFs are potentially applicable in food, oral-care, healthcare, and pharmaceutics because of their fast-dissolving character, enhanced water solubility, stability at elevated temperature, and promising antibacterial activity.


Assuntos
Acroleína/análogos & derivados , Antibacterianos/química , Antibacterianos/farmacologia , Composição de Medicamentos/métodos , Acroleína/química , Acroleína/farmacologia , Ciclodextrinas/química , Composição de Medicamentos/instrumentação , Escherichia coli/efeitos dos fármacos , Escherichia coli/crescimento & desenvolvimento , Nanofibras/química , Solubilidade , Temperatura Ambiente
4.
J Microbiol ; 57(9): 781-794, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31452043

RESUMO

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


Assuntos
Antibacterianos/toxicidade , Burkholderia/química , Proteínas de Escherichia coli/genética , Escherichia coli/efeitos dos fármacos , Doenças das Plantas/microbiologia , Pirimidinonas/toxicidade , Triazinas/toxicidade , Tropolona/toxicidade , Antibacterianos/metabolismo , Burkholderia/metabolismo , Escherichia coli/genética , Escherichia coli/crescimento & desenvolvimento , Escherichia coli/metabolismo , Proteínas de Escherichia coli/metabolismo , Perfilação da Expressão Gênica , Regulação Bacteriana da Expressão Gênica/efeitos dos fármacos , Oryza/microbiologia , Pirimidinonas/metabolismo , Transcriptoma/efeitos dos fármacos , Triazinas/metabolismo , Tropolona/metabolismo
5.
BMC Bioinformatics ; 20(1): 447, 2019 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-31462231

RESUMO

BACKGROUND: Metabolic coupling of product synthesis and microbial growth is a prominent approach for maximizing production performance. Growth-coupling (GC) also helps stabilizing target production and allows the selection of superior production strains by adaptive laboratory evolution. To support the implementation of growth-coupling strain designs, we seek to identify biologically relevant, metabolic principles that enforce strong growth-coupling on the basis of reaction knockouts. RESULTS: We adapted an established bilevel programming framework to maximize the minimally guaranteed production rate at a fixed, medium growth rate. Using this revised formulation, we identified various GC intervention strategies for metabolites of the central carbon metabolism, which were examined for GC generating principles under diverse conditions. Curtailing the metabolism to render product formation an essential carbon drain was identified as one major strategy generating strong coupling of metabolic activity and target synthesis. Impeding the balancing of cofactors and protons in the absence of target production was the underlying principle of all other strategies and further increased the GC strength of the aforementioned strategies. CONCLUSION: Maximizing the minimally guaranteed production rate at a medium growth rate is an attractive principle for the identification of strain designs that couple growth to target metabolite production. Moreover, it allows for controlling the inevitable compromise between growth coupling strength and the retaining of microbial viability. With regard to the corresponding metabolic principles, generating a dependency between the supply of global metabolic cofactors and product synthesis appears to be advantageous in enforcing strong GC for any metabolite. Deriving such strategies manually, is a hard task, due to which we suggest incorporating computational metabolic network analyses in metabolic engineering projects seeking to determine GC strain designs.


Assuntos
Escherichia coli/crescimento & desenvolvimento , Genoma Bacteriano , Engenharia Metabólica , Redes e Vias Metabólicas , Modelos Biológicos , Simulação por Computador , Escherichia coli/genética , Escherichia coli/metabolismo
6.
Int J Food Microbiol ; 306: 108272, 2019 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-31376617

RESUMO

In this study, zein coatings containing Lauroyl-l-arginine ethyl ester monohydrochloride (LAE) were developed to be applied on polypropylene films and manufacture an active food packaging. The concentration of LAE and the addition of a suitable plasticizer (glycerol or oleic acid (OA)) were the main variables considered. Active plasticized zein films, with glycerol or oleic acid were characterized in terms of release kinetics, mechanical, barrier, optical, and antimicrobial properties. Results showed that active agent concentration, (5 and 10%), had no-significant effect on mechanical and WVP properties of the plasticized films. Films plasticized with OA presented greater water resistance, UV-light opacity, and water barrier properties than glycerol-plasticized films. On the contrary, the latter had better antimicrobial properties. The analysis of LAE release kinetics from films to different food simulants revealed different behaviours, depending on both film formulation and food simulant. Despite the lower water resistance of coatings containing glycerol, bags based on polypropylene/glycerol plasticized zein containing 10% of LAE presented a great antimicrobial activity in tests with chicken soup (real food system) contaminated with pathogen bacteria, concretely, the films showed 3.21 Log reduction against Listeria monocytogenes and 3.07 log reductions against Escherichia coli. These results suggest a promising strategy on the use of LAE-containing zein in active food packaging to control foodborne pathogens.


Assuntos
Antibacterianos/farmacologia , Arginina/análogos & derivados , Escherichia coli/crescimento & desenvolvimento , Embalagem de Alimentos/métodos , Listeria monocytogenes/crescimento & desenvolvimento , Zeína/farmacologia , Animais , Arginina/farmacologia , Galinhas , Escherichia coli/efeitos dos fármacos , Listeria monocytogenes/efeitos dos fármacos , Água
7.
Environ Monit Assess ; 191(9): 539, 2019 Aug 03.
Artigo em Inglês | MEDLINE | ID: mdl-31377943

RESUMO

The externalities generated by disorderly urbanization and lack of proper planning becomes one of the main factors that must be considered in water resource management. To address the multiple uses of water and avoid conflicts among users, decision-making must integrate these factors into quality and quantity aspects. The water quality index (WQI), using the correlation matrix and the multivariate principal component analysis (PCA) and cluster analysis (CA) techniques were used to analyze the surface water quality, considering urban, rural, and industrial regions in an integrated way, even with data gaps. The results showed that the main parameters that impacted the water quality index were dissolved oxygen, elevation, and total phosphorus. The results of PCA analysis showed 86.25% of the variance in the data set, using physicochemical and topographic parameters. In the cluster analysis, the dissolved oxygen, elevation, total coliforms, E. coli, total phosphorus, total nitrogen, and temperature parameters showed a significant correlation between the data's dimensions. In the industrial region, the characteristic parameter was the organic load, in the rural region were nutrients (phosphorus and nitrogen), and in the urban region was E. coli (an indicator of the pathogenic organisms' presence). In the classification of the samples, there was a predominance of "Good" quality, however, samples classified as "Acceptable" and "Bad" occurred during the winter and spring months (dry season) in the rural and industrial regions. Water pollution is linked to inadequate land use and occupation and population density in certain regions without access to sanitation services.


Assuntos
Monitoramento Ambiental , Escherichia coli/crescimento & desenvolvimento , Poluição da Água/análise , Qualidade da Água/normas , Recursos Hídricos , Brasil , Análise por Conglomerados , Análise Multivariada , Nitrogênio/análise , Fósforo/análise , Análise de Componente Principal , Rios , Estações do Ano , Temperatura Ambiente , Urbanização
8.
J Agric Food Chem ; 67(35): 9749-9756, 2019 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-31415718

RESUMO

Bovine lactoferrin N-lobe plays an important key in the nonimmunological defense system. In this work, the most suitable promoter Pveg was selected and the fragment coding bovine lactoferrin N-lobe was optimized according to codon bias of Bacillus. The recombinant plasmid pMA0911-Pveg-mBLF-N was introduced into Baicillus subtilis 168 to create B. subtilis/pMA0911-Pveg-mBLF-N. The bovine lactoferrin N-lobe was highly expressed at 28 °C for 15 h. Its purified protein was obtained with 16.5 mg/L and a purity of 93.6% using ammonium sulfate precipitation, Ni-NTA, and molecular exclusion. About 200 ng/mL purified bovine lactoferrin N-lobe completely inhibited cell-growth of Escherichia coli JM109 (DE3), 70.3% of Pseudomonas aeruginosa CGMCC 1.6740, and 41.5% of Staphylococcus aureus CGMCC 1.282. To our knowledge, this is the first report about active expression, purification, and characterization of bovine lactoferrin N-lobe in safe bacterium B. subtilis, which opens an available application way in the biomedical and food industries.


Assuntos
Antibacterianos/farmacologia , Bacillus subtilis/genética , Códon/genética , Lactoferrina/genética , Regiões Promotoras Genéticas , Animais , Antibacterianos/metabolismo , Bacillus subtilis/metabolismo , Clonagem Molecular , Códon/metabolismo , Escherichia coli/efeitos dos fármacos , Escherichia coli/crescimento & desenvolvimento , Expressão Gênica , Engenharia Genética , Lactoferrina/metabolismo , Lactoferrina/farmacologia , Testes de Sensibilidade Microbiana , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/crescimento & desenvolvimento , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/crescimento & desenvolvimento
9.
J Food Sci ; 84(9): 2537-2548, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31433502

RESUMO

In this study, silver (Ag), zinc oxide (ZnO), and copper oxide (CuO) metallic nanoparticles were used in preparation of carboxymethyl cellulose (CMC) nanobiocomposite films. Scanning electron microscopy (SEM), X-ray diffraction (EDXA), water vapor permeability (WVP), ultraviolet and visible light (UV-Vis) spectroscopy, and mechanical and microbial tests were used to determine the characteristics of the obtained active films. SEM results showed that the CMC nanobiocomposite films had roughness deflection levels and the EDXA test confirmed the presence of Ag, ZnO, and Cuo nanoparticles in the biopolymer tissue. UV-Vis spectroscopy confirmed that with addition of metallic nanoparticles to the pure CMC film, absorption rate increased and WVP decreased. In the mechanical tests, addition of nanoparticles also increased the tensile strength of the films, and the nanobiocomposite films exhibited higher resistance compared to the pure CMC film. Films incorporating metallic nanoparticles showed antibacterial properties against Escherichia coli and Staphylococcus aureus growth. Thus, nanobiocomposite films can be used as active packaging films and could increase the shelf-life of the food.


Assuntos
Antibacterianos/química , Carboximetilcelulose Sódica/química , Embalagem de Alimentos/instrumentação , Nanopartículas Metálicas/química , Nanocompostos/química , Antibacterianos/farmacologia , Cobre/química , Escherichia coli/efeitos dos fármacos , Escherichia coli/crescimento & desenvolvimento , Permeabilidade , Prata/química , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/crescimento & desenvolvimento , Resistência à Tração , Difração de Raios X , Óxido de Zinco/química
10.
J Med Microbiol ; 68(10): 1438-1444, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31385784

RESUMO

Introduction. Combretum leprosum (Combretaceae) is commonly found in the Northeast Region of Brazil and is known for several bioactivities, including antimicrobial ones. Because of increasing bacterial antibiotic resistance, natural products from several plants have been studied as putative adjuvants to antibiotic activity, including products from C. leprosum. Aims. This study was carried out to investigate the structural properties, bactericidal activity and antibiotic modifying action of the lupane triterpene 3ß,6ß,16ß-trihydroxylup-20(29)-ene (CLF1) isolated from C. leprosum Mart. leaves.Methods. The CLF1 was evaluated by the Fourier transform infrared spectroscopy method and the antibacterial activity of this compound was assayed alone and in association with antibiotics by microdilution assay.Results. Spectroscopic studies confirmed the molecular structure of the CLF1 and permitted assignment of the main infrared bands of this natural product. Microbiological assays showed that this lupane triterpene possesses antibacterial action with clinical relevance against Staphylococcus aureus. The CLF1 triterpene increased antimicrobial activity against the multidrug-resistant Escherichia coli 06 strain when associated with the antibiotics gentamicin and amikacin. Synergistic effects were observed against the S. aureus 10 strain in the presence of the CLF1 triterpene with the antibiotic gentamicin.Conclusion. In conclusion, the CLF1 compound may be useful in the development of antibacterial drugs against the aforementioned bacteria.


Assuntos
Antibacterianos/farmacologia , Combretum/química , Extratos Vegetais/farmacologia , Triterpenos/farmacologia , Antibacterianos/química , Antibacterianos/isolamento & purificação , Brasil , Escherichia coli/efeitos dos fármacos , Escherichia coli/crescimento & desenvolvimento , Gentamicinas/farmacologia , Extratos Vegetais/química , Extratos Vegetais/isolamento & purificação , Folhas de Planta/química , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/crescimento & desenvolvimento , Triterpenos/química , Triterpenos/isolamento & purificação
11.
Eur J Med Chem ; 180: 143-153, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31302447

RESUMO

The rise of antibiotic resistance has necessitated the development of alternative strategies for the treatment of infectious diseases. Antimicrobial peptides (AMPs), components of the innate immune response in various organisms, are promising next-generation drugs against bacterial infections. The ability of the medicinal leech Hirudo medicinalis to store blood for months with little change has attracted interest regarding the identification of novel AMPs in this organism. In this study, we employed computational algorithms to the medicinal leech genome assembly to identify amino acid sequences encoding potential AMPs. Then, we synthesized twelve candidate AMPs identified by the algorithms, determined their secondary structures, measured minimal inhibitory concentrations against three bacterial species (Escherichia coli, Bacillus subtilis, and Chlamydia thrachomatis), and assayed cytotoxic and haemolytic activities. Eight of twelve candidate AMPs possessed antimicrobial activity, and only two of them, 3967 (FRIMRILRVLKL) and 536-1 (RWRLVCFLCRRKKV), exhibited inhibition of growth of all tested bacterial species at a minimal inhibitory concentration of 10 µmol. Thus, we evidence the utility of the developed computational algorithms for the identification of AMPs with low toxicity and haemolytic activity in the medicinal leech genome assembly.


Assuntos
Antibacterianos/farmacologia , Peptídeos Catiônicos Antimicrobianos/farmacologia , Infecções Bacterianas/tratamento farmacológico , Farmacorresistência Bacteriana/efeitos dos fármacos , Algoritmos , Animais , Antibacterianos/química , Peptídeos Catiônicos Antimicrobianos/química , Bacillus subtilis/efeitos dos fármacos , Bacillus subtilis/crescimento & desenvolvimento , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Chlamydia/efeitos dos fármacos , Chlamydia/crescimento & desenvolvimento , Relação Dose-Resposta a Droga , Escherichia coli/efeitos dos fármacos , Escherichia coli/crescimento & desenvolvimento , Hirudo medicinalis , Humanos , Estrutura Molecular , Relação Estrutura-Atividade
12.
Sci Total Environ ; 690: 696-704, 2019 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-31301509

RESUMO

Wastewater treatment plants could discharge Escherichia coli and antibiotic resistant bacteria to the environment adjacent to, or downstream of their discharge point. However, their discharge also contains nutrients which could promote growth of E. coli in water environments. This study was done to clarify the potential of growth and antibiotic resistance acquisition of E. coli in a river environment. Levels of E. coli were monitored in a river that receives treated sewage effluent for over four years. River water, periphyton and sediment samples were collected at sites upstream and downstream of treated sewage inflow. Concentrations of E. coli increased in river water and periphyton at the sites downstream of the treated sewage inflow, although levels of E. coli were very low or below detection limit in the treated sewage samples. Concentrations of Chlorophyll a increased at the downstream sites, likely due to nutrient input from the treated sewage. Based on pulsed field gel electrophoresis, identical genotype occurred at multiple sites both upstream and downstream of the treated sewage inflow. However, strains resistant to antibiotics such as ampicillin, cefazolin, ciprofloxacin, and chloramphenicol were more frequently obtained from the downstream sites than the upstream sites. Multidrug resistant E. coli strains were detected in periphyton and sediment samples collected at the downstream sites. Non-resistant strains with PDGE genotype identical to the multi-drug strains were also detected, indicating that E. coli might have become resistant to antibiotics by acquiring resistance genes via horizontal gene transfer. Laboratory incubation experiment showed the growth of E. coli in periphyton or sediment-fed river water samples. These results suggest that the wastewater treatment inflow did not directly provide E. coli to the river water, but could promote the growth of periphyton, which could lead to the elevated levels of E. coli and the emergence of antibiotic resistant E. coli.


Assuntos
Farmacorresistência Bacteriana/genética , Monitoramento Ambiental , Escherichia coli/crescimento & desenvolvimento , Rios/microbiologia , Eliminação de Resíduos Líquidos , Esgotos/microbiologia
13.
BMC Complement Altern Med ; 19(1): 150, 2019 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-31242939

RESUMO

BACKGROUND: Traditional medicine remedies are commonly used for treatment of diverse ailments including bacterial infections. The activity against resistant bacteria and safety of some remedies sold as anti-infective treatments in market places in Buea, Southwest Cameroon were investigated as potential alternative treatment to counter increasing antibiotic resistance. METHODS: Ten remedies were purchased, their components documented and microbial load estimated. Methanol extracts of the remedies were tested for antibacterial activity by disc diffusion and microdilution. Cytotoxicity was evaluated on monkey kidney epithelial cells (LLC-MK2) while acute oral toxicity was done in BALB/c mice for the bactericidal extract. Extracts were further analysed using phytochemical tests. RESULTS: All the remedies had microbial loads above the acceptable limit of 105 CFU/g. The highest activity was produced by extracts of four remedies (TP 1, 2, 4, 6a, 6b) against all clinical isolates among which three were active against four control strains. Zones of inhibition ranged from 8 to 27 mm. Two of the four extracts produced zones ≥20 mm against multidrug resistant clinical isolates of Citrobacter freundii and Escherichia coli but were less active compared to Gentamycin positive control (P < 0.0001-0.0014). The most active extracts also recorded minimum inhibitory concentrations of 1 to 4 mg/mL. One of them (TP2) was bactericidal against a clinical isolate of methicillin-resistant Staphylococcus aureus with a minimum bactericidal concentration of 8 mg/mL. Extracts of six remedies did not show cytotoxicity and no mortality or adverse effect was recorded in the acute oral toxicity test. Phytochemical screening showed the most active extracts contained relatively high amounts of alkaloids and flavonoids. CONCLUSION: Only four of the eight remedies tested showed activity against multidrug resistant bacteria suggesting some of these remedies may not be effective against bacterial infections. Production and handling methods should be improved and the product quality controlled to ensure biosecurity. The remedies which were both active and non-toxic should be further investigated including in vivo experiments to assess their efficacy.


Assuntos
Antibacterianos/farmacologia , Compostos Fitoquímicos/farmacologia , Extratos Vegetais/farmacologia , Plantas Medicinais/química , Animais , Antibacterianos/química , Antibacterianos/isolamento & purificação , Antibacterianos/toxicidade , Bactérias/efeitos dos fármacos , Bactérias/genética , Bactérias/crescimento & desenvolvimento , Bactérias/isolamento & purificação , Infecções Bacterianas/tratamento farmacológico , Infecções Bacterianas/microbiologia , Camarões , Farmacorresistência Bacteriana Múltipla , Escherichia coli/efeitos dos fármacos , Escherichia coli/crescimento & desenvolvimento , Feminino , Humanos , Medicina Tradicional , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Staphylococcus aureus Resistente à Meticilina/crescimento & desenvolvimento , Camundongos , Camundongos Endogâmicos BALB C , Testes de Sensibilidade Microbiana , Compostos Fitoquímicos/química , Compostos Fitoquímicos/isolamento & purificação , Compostos Fitoquímicos/toxicidade , Extratos Vegetais/química , Extratos Vegetais/isolamento & purificação , Extratos Vegetais/toxicidade , Plantas Medicinais/microbiologia
14.
J Med Microbiol ; 68(8): 1244-1252, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31184571

RESUMO

The high incidence of urinary tract infection (UTI) among women and children, in combination with a lack of antibiotic efficacy with regard to pathogen eradication and recurrence prevention, as well as the negative side effects associated with antibiotics, has led researchers to explore the role of non-steroidal anti-inflammatory drugs as a primary management strategy. The aim of this study was to determine whether ibuprofen (IBU) or one of its major metabolites, 2-carboxyibuprofen (CIBU), could affect the growth and adhesion of the two most common uropathogens, Escherichia coli and Enterococcus faecalis. The bacterial growth and adhesion to the urothelial cells of E. coli UTI89 and E. faecalis 1131 in the presence of physiologically relevant concentrations of IBU and CIBU were assessed. The effect of IBU on bacterial adhesion to urothelial cells was also assessed following exposure to trimethoprim/sulfamethoxazole (TMP/SMX) and nitrofurantoin. Bacterial growth was not affected by IBU. Further, only at high levels of IBU not regularly found in the bladder was there a significant increase in E. faecalis 1131 attachment at growth inhibitory concentrations of TMP/SMX. There was no effect on the attachment of E. faecalis or E. coli to urothelial cells in the presence of nitrofurantoin. These studies indicate that the beneficial effects of IBU for UTI management are likely mediated through its anti-inflammatory properties rather than direct interactions with uropathogens in the bladder.


Assuntos
Anti-Inflamatórios não Esteroides/farmacologia , Enterococcus faecalis/isolamento & purificação , Escherichia coli/isolamento & purificação , Ibuprofeno/farmacologia , Infecções Urinárias/microbiologia , Anti-Infecciosos Urinários/farmacologia , Bactérias/efeitos dos fármacos , Aderência Bacteriana/efeitos dos fármacos , Linhagem Celular , Enterococcus faecalis/efeitos dos fármacos , Enterococcus faecalis/crescimento & desenvolvimento , Enterococcus faecalis/fisiologia , Escherichia coli/efeitos dos fármacos , Escherichia coli/crescimento & desenvolvimento , Escherichia coli/fisiologia , Humanos , Ibuprofeno/análogos & derivados , Testes de Sensibilidade Microbiana , Viabilidade Microbiana/efeitos dos fármacos , Nitrofurantoína/farmacologia , Combinação Trimetoprima e Sulfametoxazol/farmacologia , Urotélio
15.
Biotechnol Lett ; 41(8-9): 1007-1014, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31147809

RESUMO

OBJECTIVES: Microbial biofilms have become one of the most significant causes of nosocomial infections. The aim of this study was to examine the potential quorum sensing inhibitor activities of Lactobacillus rhamnosus GG microcapsules. RESULTS: Lactobacillus rhamnosus GG microcapsules effectively inhibited initial biofilm formation at a concentration of 2.5 × 108 CFU/mL. Furthermore, the inhibition rate was increased to 79% in the Lactobacillus rhamnosus GG microcapsules group, resulting in a reduction in the biofilm maturation stage. In addition, real-time PCR analysis revealed that the LGG microcapsules can act as effective inhibitors of transcriptional activators of the quorum sensing circuit in E.coli, luxS, lsrK, and lsrR. CONCLUSIONS: Lactobacillus rhamnosus GG microcapsules can effectively inhibit biofilm formation and disturb mature biofilms.


Assuntos
Antibiose , Biofilmes/crescimento & desenvolvimento , Escherichia coli/crescimento & desenvolvimento , Lactobacillus rhamnosus/crescimento & desenvolvimento , Cápsulas , Técnicas de Cocultura
16.
Microb Pathog ; 135: 103570, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31158492

RESUMO

Escherichia coli can cause severe, acute hemorrhagic pneumonia and systemic infection in farmed foxes, raccoon dogs and minks, leading to considerable economic losses to the farmers. It is well established that the htrA-encoded serine protease HtrA is critical for bacterial growth and survival under stress, and HtrA has been determined to be a potential vaccine target. However, the roles of HtrA in E. coli pathogenesis remain unknown. In this study, we generated an htrA-deletion mutant of the E. coli protype strain HBCLE-12 that causes pneumonia in silver foxes and then evaluated the changes in bacterial physiological characteristics in the absence of HtrA. The data show that knockout of the htrA gene did not affect growth and biochemical characteristics but led to impaired virulence of the strain. Increased susceptibility to environmental stresses, impaired survival in serum, and reduced biofilm formation may contribute to the virulence attenuation of the mutant. Furthermore, the HtrA-deficient mutant was subjected to RNA-seq analysis, and 16 differentially expressed genes were determined. This study provided insight that HtrA plays a definitive role in E. coli-induced infection.


Assuntos
Infecções por Escherichia coli/veterinária , Escherichia coli/enzimologia , Escherichia coli/genética , Raposas/microbiologia , Proteínas de Choque Térmico/genética , Proteínas de Choque Térmico/metabolismo , Proteínas Periplásmicas/genética , Proteínas Periplásmicas/metabolismo , Serina Endopeptidases/genética , Serina Endopeptidases/metabolismo , Doenças dos Animais/microbiologia , Animais , Proteínas de Bactérias , Biofilmes/crescimento & desenvolvimento , Proteínas e Peptídeos de Choque Frio/genética , Escherichia coli/crescimento & desenvolvimento , Escherichia coli/patogenicidade , Regulação Bacteriana da Expressão Gênica , Técnicas de Inativação de Genes , Camundongos , Pneumonia/microbiologia , Pneumonia/veterinária , Deleção de Sequência , Estresse Fisiológico/genética , Transcriptoma , Virulência/genética , Fatores de Virulência/genética
17.
Appl Microbiol Biotechnol ; 103(15): 6169-6186, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31165225

RESUMO

Ulcerative colitis (UC) is a chronic relapsing disease. Treatment of UC would benefit from specific targeting of therapeutics to the intestine. Previous studies have demonstrated that bovine lactoferricin and lactoferrampin have bactericidal, anti-inflammatory, and immunomodulatory effects. Here, we investigated whether oral administration of a bovine lactoferricin-lactoferrampin (LFCA)-encoding Lactococcus lactis (LL-LFCA) strain could alleviate experimental colitis. LFCA derived from LL-LFCA inhibited the growth of Escherichia coli and Staphylococcus aureus in vitro. In mice, administration of LL-LFCA decreased the disease activity index and attenuated dextran sulfate sodium (DSS)-induced body weight loss and colon shortening. LL-LFCA treatment also ameliorated DSS-induced colon damage, inhibited inflammatory cell infiltration, significantly decreased myeloperoxidase activity, and ameliorated DSS-induced disruption of intestinal permeability and tight junctions. In addition, 16S rDNA sequencing showed that LL-LFCA reversed DSS-induced gut dysbiosis. The production of proinflammatory mediators in serum and the colon was also reduced by administration of LL-LFCA. In vitro, LFCA derived from LL-LFCA decreased the messenger RNA expression of proinflammatory factors. The underlying mechanisms may involve inhibition of the nuclear factor kappa B (NF-κB) pathway. The results demonstrate that LL-LFCA ameliorates DSS-induced intestinal injury in mice, suggesting that LL-LFCA might be an effective drug for the treatment of inflammatory bowel diseases.


Assuntos
Antibacterianos/metabolismo , Colite/patologia , Colite/terapia , Lactococcus lactis/metabolismo , Lactoferrina/metabolismo , Fragmentos de Peptídeos/metabolismo , Proteínas Recombinantes/metabolismo , Animais , Colite/induzido quimicamente , Modelos Animais de Doenças , Disbiose/terapia , Escherichia coli/efeitos dos fármacos , Escherichia coli/crescimento & desenvolvimento , Microbioma Gastrointestinal/efeitos dos fármacos , Lactococcus lactis/genética , Lactococcus lactis/crescimento & desenvolvimento , Lactoferrina/genética , Camundongos , Fragmentos de Peptídeos/genética , Proteínas Recombinantes/genética , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/crescimento & desenvolvimento , Resultado do Tratamento
18.
Chemotherapy ; 64(1): 22-27, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31167192

RESUMO

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


Assuntos
Proteínas de Bactérias/metabolismo , Peptídeo Sintases/metabolismo , beta-Alanina/metabolismo , Proteínas de Bactérias/antagonistas & inibidores , Sítios de Ligação , Escherichia coli/efeitos dos fármacos , Escherichia coli/enzimologia , Escherichia coli/crescimento & desenvolvimento , Simulação de Acoplamento Molecular , Peptídeo Sintases/antagonistas & inibidores , Estrutura Terciária de Proteína , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/crescimento & desenvolvimento , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/crescimento & desenvolvimento , beta-Alanina/análogos & derivados , beta-Alanina/farmacologia
19.
Environ Pollut ; 249: 1106-1114, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31146316

RESUMO

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


Assuntos
Escherichia coli/efeitos dos fármacos , Grafite/toxicidade , Estresse Oxidativo/efeitos dos fármacos , Staphylococcus aureus/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Escherichia coli/crescimento & desenvolvimento , Grafite/efeitos da radiação , Oxirredução , Processos Fotoquímicos , Espécies Reativas de Oxigênio/metabolismo , Staphylococcus aureus/crescimento & desenvolvimento , Poluentes Químicos da Água/efeitos da radiação
20.
BMC Bioinformatics ; 20(1): 309, 2019 Jun 11.
Artigo em Inglês | MEDLINE | ID: mdl-31185910

RESUMO

BACKGROUND: Fluorescent reporter genes have become widely used for monitoring gene expression in living cells. When a microbial strain carrying a reporter gene is grown in a microplate reader, the fluorescence and the absorbance (optical density) of the culture can be automatically measured every few minutes in a highly parallelized way. The extraction of useful information from the resulting large amounts of data is not easy to achieve, because the fluorescence and absorbance measurements are only indirectly related to promoter activities and protein concentrations, requiring mathematical models of the expression of reporter genes for their interpretation. Although the principles of the analysis of reporter gene data are well-established today, there is a lack of general-purpose bioinformatics tools based on generic measurement models and sound inference procedures. This has motivated the development of WellInverter, a web application based on well-known methods for regularized linear inversion. RESULTS: We present a new version of WellInverter that considerably improves the performance and usability of the original application. In particular, we have put in place a parallel computing architecture with a load balancer to distribute analysis queries over several back-end servers, we have completely redesigned the graphical user interface to better support the different analysis steps, and we have developed a plug-in system for the parsing of data files produced by microplate readers from different manufacturers. We illustrate the functioning of WellInverter by analyzing data of the expression of a fluorescent reporter gene controlled by a phage promoter in growing Escherichia coli populations. We show that the expression pattern in different growth media, supporting different growth rates, corresponds to the pattern expected for a constitutive gene. CONCLUSIONS: The new version of WellInverter is a robust, easy-to-use and scalable web application, which has been deployed on two publicly accessible web servers and which can also be installed locally. A demo version of the application with two sample datasets is available on-line.


Assuntos
Biologia Computacional/métodos , Genes Reporter , Internet , Software , Algoritmos , Escherichia coli/genética , Escherichia coli/crescimento & desenvolvimento , Fluorescência , Genes Bacterianos , Regiões Promotoras Genéticas , Interface Usuário-Computador
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