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1.
Food Chem ; 338: 127867, 2021 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-32829293

RESUMO

This is the first time that active double-layered furcellaran/gelatin hydrolysate films containing Ala-Tyr peptide were developed and characterised for their properties. Afterwards, films were used on Atlantic mackerel stored at -18 °C for 4 months and samples were analysed for changes in their microbiological quality, TVB-N, biogenic amine content, fatty acid composition and TBARS. Active films had higher TS (13.4 MPa) and lower WS (62.8%). The films showed no DPPH radical scavenging properties but high FRAP (6.6 mMol Trolox/mg). No significant effects on the oxidation of fish samples were observed with TBARS increasing from 12.04 to 22.50 mg/kg. Freezing successfully inhibited the growth of microorganisms and no differences in microbiological growth or biogenic amine formation were observed. However, the application of films inhibited the formation of TVB-N. Antimicrobiological properties of the film should be further investigated during storage of perishable food products at temperatures above 0 °C.


Assuntos
Alginatos/química , Dipeptídeos/química , Armazenamento de Alimentos/métodos , Gelatina/química , Perciformes/metabolismo , Gomas Vegetais/química , Animais , Antioxidantes/química , Aminas Biogênicas/análise , Cromatografia Líquida de Alta Pressão , Temperatura Baixa , Dipeptídeos/farmacologia , Conservação de Alimentos/métodos , Peptídeos/química , Peptídeos/farmacologia , Perciformes/microbiologia , Pseudomonas/efeitos dos fármacos , Pseudomonas/isolamento & purificação , Resistência à Tração
2.
Arch Microbiol ; 202(9): 2525-2532, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32653933

RESUMO

The adverse effects of chemical pesticides on human health and environment cannot be ignored, hence it seems that novel alternative compounds should be applied to control plant pathogens. Among various alternative sources, natural compounds such as plant essential oils, plant extracts and recombinant antimicrobial peptides are of significance. The aim of the present study was to investigate antimicrobial activity of plants essential oils and plant extracts of six medicinal plants (Lippia citriodora, Ferula gummosa, Bunium persicum, Mentha piperita, Plantago major and Salvadora persica) along with a chimera peptide of camel lactoferrin, which is the most important antimicrobial component of camel milk, against Pseudomonas tolaasii and Trichoderma harzianum as pathogens of white button mushroom. The antibacterial activity test was conducted under in vitro conditions through disc diffusion method. The results showed that chimera camel lactoferrin peptide, with the highest amount of inhibitory zone (14.63 mm in 20 µg/mL concentration), has a significant difference in antibacterial activity compared to other treatments. Ferula gummosa conferred no antibacterial activity. Also, the results of antifungal effects indicated that plant essential oils and extracts have more antifungal activity than recombinant peptide. Generally, L. citriodora, B. persicum, M. piperita treatments could completely prevent growth of fungal in in vitro conditions. Therefore, using the mentioned plants can be a good replacement for reducing the chemical pesticides against pathogenic agents of button mushroom, without any adverse effects on environment and human health.


Assuntos
Lactoferrina/farmacologia , Óleos Voláteis/farmacologia , Extratos Vegetais/farmacologia , Pseudomonas/efeitos dos fármacos , Trichoderma/efeitos dos fármacos , Agaricus , Animais , Antibacterianos/farmacologia , Anti-Infecciosos/farmacologia , Antifúngicos/farmacologia , Fungos/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Leite/química , Óleos Vegetais/farmacologia , Plantas Medicinais/química
3.
Int J Food Microbiol ; 331: 108732, 2020 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-32521374

RESUMO

The present study aimed to evaluate the anti-quorum sensing (anti-QS) and anti-proteolytic potentials of tarragon essential oil (TEO) and its major compounds against food-associated Pseudomonas spp. The activities were verified by in vitro, in silico and in situ approaches. In this work, methyl eugenol (ME)- and ß-phellandrene (ß-PH)-rich TEO was investigated. TEO at subMIC increased the percentage of saturated fatty acids in the bacterial membranes (from 7 to 22%) and exhibited anti-quorum sensing via decreasing the efficiency of QS autoinducer synthesis [3-oxo-C12-HSL (from 2.028 µg/mL to

Assuntos
Artemisia/química , Óleos Voláteis/farmacologia , Proteólise/efeitos dos fármacos , Pseudomonas/efeitos dos fármacos , Percepção de Quorum/efeitos dos fármacos , 4-Butirolactona/análogos & derivados , 4-Butirolactona/isolamento & purificação , 4-Butirolactona/farmacologia , Animais , Antibacterianos/isolamento & purificação , Antibacterianos/farmacologia , Simulação por Computador , Peixes/microbiologia , Homosserina/análogos & derivados , Homosserina/isolamento & purificação , Homosserina/farmacologia , Óleos Voláteis/química , Óleos Voláteis/isolamento & purificação , Pseudomonas/isolamento & purificação
5.
Int J Food Microbiol ; 328: 108664, 2020 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-32474229

RESUMO

To control Pseudomonas and Shewanella as important psychrotrophic spoilage bacteria in fish meat, we used ethanolic extracts of oregano (Origanum vulgare subsp. vulgare) and nettle (Urtica dioica), with phytochemical characterisation of the extracts and their bioactive compounds. Liquid chromatography coupled with photodiode array detection and electrospray ionisation-mass spectrometry was used for qualitative compositional determination of the extracts. Four main compounds were identified in the oregano extract, with rosmarinic acid the most abundant, followed by three glycosylated phenolics, one of which is reported for the first time in O. vulgare: 4'-O-ß-d-glucopyranosyl-3',4'-dihydroxybenzyl-4-hydroxybenzoate. Six main compounds were identified in the nettle extract, as caffeoylmalic acid and five flavonoid glycosides. These oregano and nettle ethanolic extracts showed in-vitro antimicrobial activities against selected Pseudomonas and Shewanella strains in broth and fish meat homogenate when evaluated at two inoculum concentrations. The antimicrobial activities were more pronounced for the nettle extract at the lower inoculum concentration, and for both the Shewanella strains. Growth inhibition in the fish meat homogenate was evaluated at 3.13 mg/mL and 1.56 mg/mL at 5 °C. Again, the nettle extract showed greater antimicrobial activity, which was seen as the lowest maximum growth rate, followed by the oregano extract, which was inhibitory only at 3.13 mg/mL. Finally, the extracts were applied to fish meat that was then stored at 5 °C for 9 days. Evaluation here was for the counts of the mesophilic, psychrotrophic, Pseudomonas and H2S producers. These confirmed the better antimicrobial effects of the nettle extract, especially against the H2S-producing bacteria, which included Shewanella. Both of the extracts were rich in glycosides of flavonoids and phenolic acids. The enzymatic activities of the Pseudomonas and Shewanella spoilage bacteria and their actions on the phenolic glycosides from natural sources will be further investigated.


Assuntos
Doenças dos Peixes/tratamento farmacológico , Origanum/química , Extratos Vegetais/farmacologia , Pseudomonas/efeitos dos fármacos , Shewanella/efeitos dos fármacos , Urtica dioica/química , Animais , Ácidos Cafeicos/farmacologia , Cinamatos/farmacologia , Depsídeos/farmacologia , Peixes/microbiologia , Flavonoides , Microbiologia de Alimentos , Hidroxibenzoatos/farmacologia , Malatos/farmacologia , Fenóis/química , Alimentos Marinhos/microbiologia , Espectrometria de Massas por Ionização por Electrospray
6.
Int J Infect Dis ; 98: 41-50, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32535299

RESUMO

OBJECTIVES: Alternative dosing strategies for ß-lactams - the most common antibiotics used to treat critically ill patients with respiratory tract infections - have been recommended to maximize the duration of exposure and reduce drug resistance. The objective of this study was to evaluate whether extended infusion of antipseudomonal ß-lactams improves mortality and clinical efficacy. METHODS: Two independent authors identified eligible trials by searching the PubMed, Cochrane Library, Scopus, and ICHUSHI databases, in both English and Japanese, up to June 2019. Data were extracted from both randomized controlled and observational trials comparing extended infusion (≥3h) with intermittent infusion in critically ill patients. The primary outcome was all-cause mortality. Risk differences (RD) and 95% confidential intervals (CI) were calculated using a random-effects model and subgroup analyses were performed. Sensitivity and heterogeneity were also evaluated. RESULTS: Nine studies involving 1508 participants were included in the meta-analysis. Mortality was lower for extended infusion than for intermittent infusion (RD -0.10; 95% CI -0.15 to -0.04). However, no significant between-group differences in clinical success, length of ICU stay, length of hospital stay, and antibiotic duration were observed. CONCLUSIONS: Extended infusions of ß-lactams were associated with reduced mortality rates but not with clinical success.


Assuntos
Antibacterianos/administração & dosagem , Estado Terminal/terapia , Infecções Respiratórias/tratamento farmacológico , beta-Lactamas/administração & dosagem , Adulto , Idoso , Idoso de 80 Anos ou mais , Gerenciamento de Dados , Humanos , Bombas de Infusão , Tempo de Internação , Pessoa de Meia-Idade , Pseudomonas/efeitos dos fármacos , Pseudomonas/fisiologia , Infecções Respiratórias/microbiologia , Infecções Respiratórias/mortalidade , Fatores de Tempo , Resultado do Tratamento
7.
Sci Rep ; 10(1): 8196, 2020 05 18.
Artigo em Inglês | MEDLINE | ID: mdl-32424195

RESUMO

An increasing interest in the development of products of natural origin for crop disease and pest control has emerged in the last decade. Here we introduce a new family of strawberry acyl glycosides (SAGs) formed by a trisaccharide (GalNAc-GalNAc-Glc) and a monounsaturated fatty acid of 6 to 12 carbon atoms linked to the glucose unit. Application of SAGs to Arabidopsis thaliana (hereafter Arabidopsis) plants triggered a transient oxidative burst, callose deposition and defense gene expression, accompanied by increased protection against two phytopathogens, Pseudomonas viridiflava and Botrytis cinerea. SAGs-induced disease protection was also demonstrated in soybean infected with the causal agent of target spot, Corynespora cassiicola. SAGs were shown to exhibit important antimicrobial activity against a wide-range of bacterial and fungal phytopathogens, most probably through membrane destabilization, and the potential use of SAGs as a biofungicide for postharvest disease protection was demonstrated on lemon fruits infected with Penicillium digitatum. Plant growth promotion by application of SAGs was shown by augmented primary root elongation, secondary roots development and increased siliques formation in Arabidopsis, whereas a significant increment in number of seed pods was demonstrated in soybean. Stimulation of radicle development and the induction of an auxin-responsive reporter system (DR5::GUS) in transgenic Arabidopsis plants, suggested that SAGs-stimulated growth at least partly acts through the auxin response pathway. These results indicate that strawberry fatty acid glycosides are promising candidates for the development of environmental-friendly products for disease management in soybean and lemon.


Assuntos
Antibacterianos/química , Antibacterianos/farmacologia , Fragaria/química , Glicosídeos/química , Glicosídeos/farmacologia , Doenças das Plantas/prevenção & controle , Arabidopsis/efeitos dos fármacos , Arabidopsis/crescimento & desenvolvimento , Arabidopsis/microbiologia , Bioensaio , Botrytis/efeitos dos fármacos , Botrytis/fisiologia , Doenças das Plantas/microbiologia , Pseudomonas/efeitos dos fármacos , Pseudomonas/fisiologia
8.
Ecotoxicol Environ Saf ; 200: 110767, 2020 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-32470679

RESUMO

The occurrence and dissemination of antibiotic resistant genes (ARGs) that are associated with clinical pathogens and the evaluation of associated risks are still under-investigated in developing countries under tropical conditions. In this context, cultivable and molecular approaches were performed to assess the dissemination of bacteria and the antibiotic resistance genes in aquatic environment in Kinshasa, Democratic Republic of the Congo. Cultivable approach quantified ß-lactam, carbapenem resistant, and total Escherichia coli and Enterobacteriaceae in river sediments and surface waters that receive raw hospital effluents. The molecular approach utilized Quantitative Polymerase Chain Reaction (qPCR) to quantify the total bacteria and the richness of relevant bacteria (Escherichia coli, Enterococcus, and Pseudomonas), and antibiotic resistance genes (ARGs: blaOXA-48, blaCTX-M, blaIMP, blaTEM) in sediment samples. Statistical analysis were employed to highlight the significance of hospital contribution and seasonal variation of bacteria and ARGs into aquatic ecosystems in suburban municipalities of Kinshasa, Democratic Republic of the Congo. The contribution of hospitals to antibiotic resistance proliferation is higher in the dry season than during the wet season (p < 0.05). Hospital similarly contributed Escherichia coli, Enterococcus, and Pseudomonas and ARGs significantly to the sediments in both seasons (p < 0.05). The organic matter content correlated positively with E. coli (r = 0.50, p < 0.05). The total bacterial load correlated with Enterococcus, and Pseudomonas (0.49 < r < 0.69, p < 0.05). Each ARG correlated with the total bacterial load or at least one relevant bacteria (0.41 < r < 0.81, p < 0.05). Our findings confirm that hospital wastewaters contributed significantly to antibiotic resistance profile and the significance of this contribution increased in the dry season. Moreover, our analysis highlights this risk from untreated hospital wastewaters in developing countries, which presents a great threat to public health.


Assuntos
Resistência Microbiana a Medicamentos/genética , Genes Bacterianos/efeitos dos fármacos , Hospitais , Rios/microbiologia , Águas Residuárias/microbiologia , Antibacterianos/análise , Antibacterianos/farmacologia , Cidades , República Democrática do Congo , Ecossistema , Enterococcus/efeitos dos fármacos , Enterococcus/genética , Escherichia coli/efeitos dos fármacos , Escherichia coli/genética , Pseudomonas/efeitos dos fármacos , Pseudomonas/genética , Rios/química , Clima Tropical , Águas Residuárias/química
9.
Food Chem ; 324: 126886, 2020 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-32344351

RESUMO

This study aimed to investigate preservative effects of ethyl lauroyl arginate hydrochloride (LAE) on microbiota, quality, and physiochemical changes of container-cultured largemouth bass fillets stored at 4 °C. The results showed LAE treatment was effective in reducing bacterial growth and attenuating physiochemical changes (flesh color, trichloroacetic acid (TCA)-soluble peptides, total volatile basic nitrogen (TVB-N), ammonia concentration, and biogenic amines) of bass fillets, while had relatively weak effect on the degradation of ATP-related compounds. As a result, LAE treatment retarded the deterioration of sensory attributes, and thus prolonged the shelf-life of largemouth bass fillets for 4 days. In addition, LAE treatment decreased the relative abundance of Pseudomonas in bass fillets, and thus changed the microbial composition. Moreover, correlation analysis between physiochemical changes and bacterial genera showed that Pseudomonas was well correlated with TCA-soluble peptides, TVB-N, ammonia, putrescine and histamine, while Aeromonas tended to have strong potentials in producing ammonia and cadaverine.


Assuntos
Arginina/análogos & derivados , Bass/microbiologia , Microbiota/efeitos dos fármacos , Músculos/química , Amônia/análise , Animais , Arginina/farmacologia , Bass/metabolismo , Aminas Biogênicas/análise , Temperatura Baixa , Armazenamento de Alimentos , Concentração de Íons de Hidrogênio , Músculos/metabolismo , Músculos/microbiologia , Pseudomonas/efeitos dos fármacos , Alimentos Marinhos/análise
10.
Food Microbiol ; 90: 103494, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32336371

RESUMO

P. psychrophila is implicated in fish spoilage especially under cold storage. In the present study, tandem mass tag (TMT) quantitative proteomic analysis was performed to clarify the molecular mechanism for the inhibitory effect of chitosan oligosaccharides (COS) against P. psychrophila in fish juice system. The MIC and MBC of the COS against P. psychrophila were 6 and 8 mg/mL, respectively. Compared with the untreated control, a total of 370 proteins (163 up-regulated and 207 down-regulated) were identified as differentially expressed proteins (DEPs, >1.5-fold or < 0.67-fold, P < 0.05) in P. psychrophila when exposed to 6 mg/mL COS. Bioinformatics analysis indicated that the DEPs were mainly involved in the cell wall/membrane, cell motility, and electron-transport chain; DNA replication, RNA transcription and translation, posttranslational modifications of proteins; TCA cycle, and the transport and metabolism of amino acid, carbohydrate, and ion. The scanning electron microscope (SEM) and fourier-transform infrared spectroscopy (FT-IR) analysis further validated that cell structure especially the cell wall/membrane was damaged after COS treatment. The results in this study presented an important step toward understanding the response of P. psychrophila cells to COS at the proteome level.


Assuntos
Quitosana/farmacologia , Peixes/microbiologia , Oligossacarídeos/farmacologia , Proteômica/métodos , Pseudomonas/genética , Animais , Membrana Celular/efeitos dos fármacos , Replicação do DNA/efeitos dos fármacos , Oligossacarídeos/química , Biossíntese de Proteínas/efeitos dos fármacos , Pseudomonas/química , Pseudomonas/efeitos dos fármacos , Transcrição Genética/efeitos dos fármacos
11.
Ecotoxicol Environ Saf ; 194: 110378, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32146194

RESUMO

The primary purpose of this study was to systematically explore the complete metabolic pathway and tolerance mechanism of strain DNB-S1 to dibutyl phthalate (DBP), and the effect of DBP on energy metabolism of DNB-S1. Here, DNB-S1, a strain of Pseudomonas sp. that was highly effective in degrading DBP, was identified, and differentially expressed metabolites and metabolic networks of DBP were studied. The results showed that the differentially expressed metabolites were mainly aromatic compounds and lipid compounds, with only a few toxic intermediate metabolites. It speculated that phthalic acid, salicylic acid, 3-hydroxybenzoate acid, 3-Carboxy-cis, cis-muconate, fumarypyravate were intermediate metabolites of DBP. Their up-regulation indicated that there were two metabolic pathways in the degradation of DBP (protocatechuate pathway and gentisate pathway), which had been verified by peak changes at 290 nm, 320 nm, 330 nm, and 375 nm in the enzymatic method. Also, aspartate, GSH, and other metabolites were up-regulation, indicating that DNB-S1 had a high tolerance to DBP and maintained cell homeostasis, which was also one of the essential reasons to ensure the efficient degradation of DBP. Altogether, this study firstly proposed two pathways to degrade DBP and comprehensively explored the effect of DBP on the metabolic function of DNB-S1, which enriched the study of microbial metabolism of organic pollutants, and which provided a basis for the application of metabolomics.


Assuntos
Dibutilftalato/metabolismo , Poluentes Ambientais/metabolismo , Pseudomonas/metabolismo , Adaptação Fisiológica/efeitos dos fármacos , Biodegradação Ambiental , Dibutilftalato/toxicidade , Metabolismo Energético/efeitos dos fármacos , Poluentes Ambientais/toxicidade , Pseudomonas/efeitos dos fármacos , Pseudomonas/crescimento & desenvolvimento
12.
Ecotoxicol Environ Saf ; 194: 110434, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32155483

RESUMO

A factor that may significantly increase the efficacy of phytoextraction is soil bioaugmentation with specific bacteria, which can alter the composition of rhizospheric and endophytic bacterial communities. The aim of this study was to compare the effect of soil treatment with living (bioaugmentation) and dead (control) cells of the plant growth-promoting metal-resistant endophytic strain Pseudomonas sp. H15 on the bacterial community composition in the rhizo- and endo-sphere of white mustard during enhanced phytoextraction. The bacterial communities in the rhizosphere were dominated (51.7-68.2%) by Proteobacteria, regardless of the soil treatment or sampling point. A temporary increase in the number of sequences belonging to Gammaproteobacteria (up to 37.3%) was only observed 24 h after the soil treatment with living Pseudomonas sp. H15 cells, whereas for the remaining samples, the relative abundance of this class did not exceed 7.1%. The relative abundance of Proteobacteria in the endosphere of the roots, stems, and leaves of white mustard was higher in the control than in bioaugmented plants. The most pronounced dominance of the Gammaproteobacteria sequences was observed in the stems and leaves of the control plants at the first sampling point, which strongly indicates the ability of the plants to rapidly uptake DNA from soil and translocate it to the aboveground parts of the plants. Additionally, the bioaugmentation of the soil caused a diverse shift in the bacterial communities in the rhizo- and endo-sphere of white mustard compared to control. The most distinct differences, which were dependent on the treatment, were observed in the endosphere of plants at the beginning of the experiment and decreased over time. These results indicate that the rhizo- and endo-biome of white mustard reacts to soil bioaugmentation and may influence the efficiency of bacterial-assisted phytoextraction.


Assuntos
Biodegradação Ambiental , Pseudomonas/metabolismo , Sinapis/metabolismo , Microbiologia do Solo , Bactérias/efeitos dos fármacos , Brassica , Desenvolvimento Vegetal , Folhas de Planta/química , Raízes de Plantas/química , Pseudomonas/efeitos dos fármacos , Rizosfera , Solo , Poluentes do Solo/análise
13.
Int J Mol Sci ; 21(6)2020 Mar 13.
Artigo em Inglês | MEDLINE | ID: mdl-32183193

RESUMO

Saliva plays a crucial role in oral cavity. In addition to its buffering and moisturizing properties, saliva fulfills many biofunctional requirements, including antibacterial activity that is essential to assure proper oral microbiota growth. Due to numerous extra- and intra-systemic factors, there are many disorders of its secretion, leading to oral dryness. Saliva substitutes used in such situations must meet many demands. This study was design to evaluate the effect of core-shell magnetic nanoparticles (MNPs) adding (gold-coated and aminosilane-coated nanoparticles NPs) on antimicrobial (microorganism adhesion, biofilm formation), rheological (viscosity, viscoelasticity) and physicochemical (pH, surface tension, conductivity) properties of three commercially available saliva formulations. Upon the addition of NPs (20 µg/mL), antibacterial activity of artificial saliva was found to increase against tested microorganisms by 20% to 50%. NPs, especially gold-coated ones, decrease the adhesion of Gram-positive and fungal cells by 65% and Gram-negative bacteria cells by 45%. Moreover, the addition of NPs strengthened the antimicrobial properties of tested artificial saliva, without influencing their rheological and physicochemical properties, which stay within the range characterizing the natural saliva collected from healthy subjects.


Assuntos
Anti-Infecciosos/química , Nanopartículas de Magnetita/química , Saliva Artificial/química , Anti-Infecciosos/farmacologia , Aderência Bacteriana/efeitos dos fármacos , Biofilmes/efeitos dos fármacos , Candida/efeitos dos fármacos , Elasticidade , Condutividade Elétrica , Ouro/química , Pseudomonas/efeitos dos fármacos , Saliva Artificial/farmacologia , Silanos/química , Streptococcus/efeitos dos fármacos , Tensão Superficial , Viscosidade
14.
Nat Rev Microbiol ; 18(5): 286-298, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32152509

RESUMO

The antibacterial agents currently in clinical development are predominantly derivatives of well-established antibiotic classes and were selected to address the class-specific resistance mechanisms and determinants that were known at the time of their discovery. Many of these agents aim to target the antibiotic-resistant priority pathogens listed by the WHO, including Gram-negative bacteria in the critical priority category, such as carbapenem-resistant Acinetobacter, Pseudomonas and Enterobacterales. Although some current compounds in the pipeline have exhibited increased susceptibility rates in surveillance studies that depend on geography, pre-existing cross-resistance both within and across antibacterial classes limits the activity of many of the new agents against the most extensively drug-resistant (XDR) and pan-drug-resistant (PDR) Gram-negative pathogens. In particular, cross-resistance to unrelated classes may occur by co-selection of resistant strains, thus leading to the rapid emergence and subsequent spread of resistance. There is a continued need for innovation and new-class antibacterial agents in order to provide effective therapeutic options against infections specifically caused by XDR and PDR Gram-negative bacteria.


Assuntos
Acinetobacter/efeitos dos fármacos , Antibacterianos/farmacologia , Desenvolvimento de Medicamentos/tendências , Farmacorresistência Bacteriana , Enterobacteriaceae/efeitos dos fármacos , Pseudomonas/efeitos dos fármacos , Infecções por Acinetobacter/microbiologia , Infecções por Enterobacteriaceae/microbiologia , Humanos , Infecções por Pseudomonas/microbiologia
15.
Appl Microbiol Biotechnol ; 104(7): 3061-3079, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32009198

RESUMO

Pseudomonas protegens H78 produces multiple secondary metabolites, including antibiotics and iron carriers. The guanosine pentaphosphate or tetraphosphate ((p)ppGpp)-mediated stringent response is utilized by bacteria to survive during nutritional starvation and other stresses. RelA/SpoT homologues are responsible for the biosynthesis and degradation of the alarmone (p)ppGpp. Here, we investigated the global effect of relA/spoT dual deletion on the transcriptomic profiles, physiology, and metabolism of P. protegens H78 grown to mid- to late log phase. Transcriptomic profiling revealed that relA/spoT deletion globally upregulated the expression of genes involved in DNA replication, transcription, and translation; amino acid metabolism; carbohydrate and energy metabolism; ion transport and metabolism; and secretion systems. Bacterial growth was partially increased, while the cell survival rate was significantly reduced by relA/spoT deletion in H78. The utilization of some nutritional elements (C, P, S, and N) was downregulated due to relA/spoT deletion. In contrast, relA/spoT mutation globally inhibited the expression of secondary metabolic gene clusters (plt, phl, prn, ofa, fit, pch, pvd, and has). Correspondingly, antibiotic and iron carrier biosynthesis, iron utilization, and antibiotic resistance were significantly downregulated by the relA/spoT mutation. This work highlights that the (p)ppGpp-mediated stringent response regulatory system plays an important role in inhibiting primary metabolism and activating secondary metabolism in P. protegens.


Assuntos
Guanosina Pentafosfato/metabolismo , Guanosina Tetrafosfato/metabolismo , Pseudomonas/metabolismo , Metabolismo Secundário/genética , Antibacterianos/biossíntese , Antibacterianos/farmacologia , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Farmacorresistência Bacteriana/genética , Metabolismo Energético/genética , GTP Pirofosfoquinase/genética , GTP Pirofosfoquinase/metabolismo , Deleção de Genes , Perfilação da Expressão Gênica , Regulação Bacteriana da Expressão Gênica , Viabilidade Microbiana/genética , Pseudomonas/efeitos dos fármacos , Pseudomonas/genética , Pseudomonas/crescimento & desenvolvimento , Pirofosfatases/genética , Pirofosfatases/metabolismo
16.
Diagn Microbiol Infect Dis ; 96(4): 114926, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32044188

RESUMO

Routine identification of carbapenemase-producing bacterial isolates is a lengthy process often taking up to 72 h to generate results with standard culture-based tests. Here we describe a rapid test based on the hydrolysis of nitrocefin to identify isolates producing ß-lactamase enzymes. A cocktail of inhibitors has been optimized in the reaction mix to provide specificity for carbapenemase enzymes. The developed assay has also been translated to a microfluidic platform with an optical readout (optofluidic chip). The chip has a long absorbance path (25 mm) to provide high sensitivity. A sample-to-answer has been achieved in under 30 min on these chips using colonies from culture plates. The test on this platform has the potential to provide a rapid indicative (presumptive positive) test for carbapenemase producers direct from bacteria isolated from patient samples, to rapidly trigger infection control measures and identify samples that should be prioritized for more specialized carbapenemase diagnostic assays.


Assuntos
Proteínas de Bactérias/análise , Cefalosporinas/farmacologia , Enterobacteriaceae/efeitos dos fármacos , Microfluídica/métodos , beta-Lactamases/análise , Técnicas Bacteriológicas , Colorimetria/instrumentação , Enterobacteriaceae/enzimologia , Hidrólise , Indicadores e Reagentes/química , Dispositivos Lab-On-A-Chip , Testes de Sensibilidade Microbiana , Miniaturização/instrumentação , Fenótipo , Pseudomonas/efeitos dos fármacos , Pseudomonas/enzimologia , Sensibilidade e Especificidade
17.
Molecules ; 25(2)2020 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-31936318

RESUMO

Whole-genome sequence data of the genus Streptomyces have shown a far greater chemical diversity of metabolites than what have been discovered under typical laboratory fermentation conditions. In our previous natural product discovery efforts on Streptomyces sp. MA37, a bacterium isolated from the rhizosphere soil sample in Legon, Ghana, we discovered a handful of specialised metabolites from this talented strain. However, analysis of the draft genome of MA37 suggested that most of the encoded biosynthetic gene clusters (BGCs) remained cryptic or silent, and only a small fraction of BGCs for the production of specialised metabolites were expressed when cultured in our laboratory conditions. In order to induce the expression of the seemingly silent BGCs, we have carried out a co-culture experiment by growing the MA37 strain with the Gram-negative bacterium Pseudomonas sp. in a co-culture chamber that allows co-fermentation of two microorganisms with no direct contact but allows exchange of nutrients, metabolites, and other chemical cues. This co-culture approach led to the upregulation of several metabolites that were not previously observed in the monocultures of each strain. Moreover, the co-culture induced the expression of the cryptic indole alkaloid BGC in MA37 and led to the characterization of the known indolocarbazole alkaloid, BE-13793C 1. Neither bacterium produced compound 1 when cultured alone. The structure of 1 was elucidated by Nuclear Magnetic Resonance (NMR), mass spectrometry analyses and comparison of experimental with literature data. A putative biosynthetic pathway of 1 was proposed. Furthermore, BE-13793C 1 showed strong anti-proliferative activity against HT-29 (ATCC HTB-38) cells but no toxic effect to normal lung (ATCC CCL-171) cells. To the best of our knowledge, this is the first report for the activity of 1 against HT-29. No significant antimicrobial and anti-trypanosomal activities for 1 were observed. This research provides a solid foundation for the fact that a co-culture approach paves the way for increasing the chemical diversity of strain MA37. Further characterization of other upregulated metabolites in this strain is currently ongoing in our laboratory.


Assuntos
Vias Biossintéticas , Técnicas de Cocultura/métodos , Alcaloides Indólicos/metabolismo , Metaboloma , Antibacterianos/farmacologia , Biofilmes/efeitos dos fármacos , Bioensaio , Vias Biossintéticas/efeitos dos fármacos , Vias Biossintéticas/genética , Morte Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Cromatografia Líquida de Alta Pressão , Células HT29 , Humanos , Alcaloides Indólicos/farmacologia , Testes de Sensibilidade Microbiana , Família Multigênica , Espectroscopia de Prótons por Ressonância Magnética , Pseudomonas/efeitos dos fármacos , Pseudomonas/metabolismo , Trypanosoma/efeitos dos fármacos
18.
J Sci Food Agric ; 100(5): 2305-2312, 2020 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-31960971

RESUMO

BACKGROUND: Aquaculture is the fastest growing food-production sector, and common carp (Cyprinus carpio) is one of the most cultivated fish species in the world. Due to its intrinsic characteristics, fish meat is highly susceptible to microbiological spoilage. Pseudomonas and Shewanella are the primary and secondary occurring microbiota during storage of fish meat, with significant contribution to spoilage with the formation of hydrolytic enzymes (lipases and proteases). RESULTS: With in vitro testing, we show that rosemary extract (Inolens4), buffered vinegar and their combination (SyneROX) exhibit antimicrobial effects against P. fragi, P. psychrophila, S. putrefaciens and S. xiaemensis at concentrations of 3.13 and 1.56 mg mL-1 . The combination was the most effective in inhibiting growth of selected bacteria in food model, and production of lipases and proteases during 9 days at 5 °C. In situ testing of antimicrobial dip treatment of carp meat determined that aerobic mesophilic, total psychrotrophic, Pseudomonas and hydrogen sulfide producer counts were reduced in all treatments, with the most prominent influence being shown by the combination and buffered vinegar. CONCLUSIONS: Our study highlights the importance of a multilevel assessment of the antimicrobial potential of biopreservatives under conditions comparable to those of the selected food. Investigation with bacteria and food model provided coherent and consistent data for the evaluation of the antimicrobial potential for carp meat. Combination of buffered vinegar (as active antimicrobial) and rosemary extract, with well-known and researched antioxidant properties but low in situ antimicrobial activity, represents a good potential for combined effect in preservation of fish meat. © 2020 Society of Chemical Industry.


Assuntos
Ácido Acético/antagonistas & inibidores , Carpas/microbiologia , Extratos Vegetais/química , Pseudomonas/efeitos dos fármacos , Rosmarinus/química , Shewanella/efeitos dos fármacos , Animais , Antibacterianos/farmacologia , Aquicultura , Microbiologia de Alimentos , Conservação de Alimentos , Sulfeto de Hidrogênio/análise , Testes de Sensibilidade Microbiana , Pseudomonas/crescimento & desenvolvimento , Alimentos Marinhos/microbiologia , Shewanella/crescimento & desenvolvimento , Paladar
19.
FEMS Microbiol Ecol ; 96(2)2020 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-31930390

RESUMO

The Pseudomonas genus, which includes environmental and pathogenic species, is known to present antibiotic resistances, and can receive resistance genes from multi-resistant enteric bacteria released into the environment via faecal rejects. This study was aimed to investigate the resistome of Pseudomonas populations that have been in contact with these faecal bacteria. Thus, faecal discharges originating from human or cattle were sampled (from 12 points and two sampling campaigns) and 41 Pseudomonas species identified (316 isolates studied). The resistance phenotype to 25 antibiotics was determined in all isolates, and we propose a specific antibiotic resistance pattern for 14 species (from 2 to 9 resistances). None showed resistance to aminoglycosides, tetracycline, or polymyxins. Four species carried a very low number of resistances, with none to ß-lactams. Interestingly, we observed the absence of the transcriptional activator soxR gene in these four species. No plasmid transfer was highlighted by conjugation assays, and a few class 1 but no class 2 integrons were detected in strains that may have received resistance genes from Enterobacteria. These results imply that the contribution of the Pseudomonas genus to the resistome of an ecosystem first depends on the structure of the Pseudomonas populations, as they may have very different resistance profiles.


Assuntos
Antibacterianos/farmacologia , Resistência Microbiana a Medicamentos , Pseudomonas/efeitos dos fármacos , Microbiologia da Água , Animais , Bovinos , Ecossistema , Fezes , Humanos , Integrons/genética , Plasmídeos , Pseudomonas/genética , Pseudomonas/isolamento & purificação , Tetraciclina/farmacologia
20.
Food Chem ; 305: 125454, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31505413

RESUMO

The effects of the (-)-Epigallocatechin gallate (EGCG)-gelatin biofilm treatment (EGT) on microbial composition and quality of tilapia fillets stored at low temperatures were evaluated. The changes in mechanical properties, microbial reproduction, as well as lipid and protein oxidation during fillets storage were determined. The results showed that EGT reduced the microbial count and the relative abundance of the fillets. And EGT delayed the rate of lipid oxidation and protein denaturation in fillets. Compared with the control group, EGT samples had lower K values (74% on 18 d) and biogenic amines (39 mg/kg for putrescine and 50 mg/kg for cadaverine on 21 d). According to sensory evaluation, the shelf life of tilapia fillets was extended by 6 d in the EGT group. Therefore, EGT improved the quality of cryopreserved tilapia fillets and could be considered as a potential method for fish fillet preservation.


Assuntos
Materiais Biomiméticos/química , Catequina/análogos & derivados , Armazenamento de Alimentos/métodos , Gelatina/química , Alimentos Marinhos/análise , Aeromonas/efeitos dos fármacos , Animais , Aminas Biogênicas/análise , Materiais Biomiméticos/farmacologia , Catequina/química , Peroxidação de Lipídeos/efeitos dos fármacos , Desnaturação Proteica/efeitos dos fármacos , Proteínas/química , Pseudomonas/efeitos dos fármacos , Alimentos Marinhos/microbiologia , Paladar/efeitos dos fármacos , Temperatura
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