RESUMO
Foodborne pathogens are a grave concern for the for food, medical, environmental, and economic sectors. Their ease of transmission and resistance to treatments, such as antimicrobial agents, make them an important challenge. Food tainted with these pathogens is swiftly rejected, and if ingested, can result in severe illnesses and even fatalities. This review provides and overview of the current status of various pathogens and their metabolites transmitted through food. Despite a plethora of studies on treatments to eradicate and inhibit these pathogens, their indiscriminate use can compromise the sensory properties of food and lead to contamination. Therefore, the study of detection methods such as electrochemical biosensors has been proposed, which are devices with advantages such as simplicity, fast response, and sensitivity. However, these biosensors may also present some limitations. In this regard, it has been reported that nanomaterials with high conductivity, surface-to-volume ratio, and robustness have been observed to improve the detection of foodborne pathogens or their metabolites. Therefore, in this work, we analyze the detection of pathogens transmitted through food and their metabolites using electrochemical biosensors based on nanomaterials.
Assuntos
Técnicas Biossensoriais , Técnicas Eletroquímicas , Contaminação de Alimentos , Microbiologia de Alimentos , Nanoestruturas , Técnicas Biossensoriais/métodos , Técnicas Eletroquímicas/métodos , Nanoestruturas/química , Microbiologia de Alimentos/métodos , Contaminação de Alimentos/análise , Doenças Transmitidas por Alimentos/microbiologia , Humanos , Bactérias/isolamento & purificaçãoRESUMO
Tomato plants are a crop of great economic importance worldwide. Mexico is considered the world's leading exporter of this vegetable, with a 24% market share. However, this crop can be affected by diseases such as bacterial freckle and bacterial cancer that can be introduced to plantations through infected seeds. Pesticides are used in agriculture for disease control and are considered a source of environmental pollution. Alternatives to the use of pesticides must therefore be sought. To this effect, electrolyzed water is a technology that has been shown to have antimicrobial activity. In this study, the antimicrobial activity of electrolyzed water on Pseudomonas syringaepv. tomato and Clavibactermichiganensis subsp.michiganensis was evaluated on cells suspension and tomato seed germination. Electrolyzed oxidizing water (EOW) and electrolyzed reduced water (ERW) treatments were applied for 1, 3 and 6 minutes. In addition, seeds were infected with each of the bacterial strains separately and electrolyzed water treatments were applied. Results show that oxidizing water is more efficient as an antimicrobial agent, as it achieved 100% growth reduction of the two bacterial strains after one minute of treatment. These treatments did not affect germination percentage, since germination percentages above 90% were obtained in all treatments and the seedlings were not affected in any of the evaluated variables.
O tomate é uma colheita de grande importância econômica em todo o mundo. O México é considerado o primeiro exportador desta hortaliça no mundo, com 24% de participação. No entanto, esta cultura pode ser afetada por doenças como a mancha bacteriana e o cancro bacteriano que podem ser introduzidos nas colheitas através de sementes infectadas. Os agrotóxicos são utilizados na agricultura para controlar doenças e são considerados uma fonte de contaminação ambiental. Por esse motivo, é necessário buscar alternativas ao uso de agrotóxicos. Nesse sentido, a água eletrolisada é uma tecnologia que tem demonstrado atividade antimicrobiana. No presente estudo, a atividade antimicrobiana da água eletrolisada sobre Pseudomonas syringae pv. tomate e Clavibacter michiganensis subsp. michiganensis emcélulasem suspensão e na germinação de sementes de tomate. Os tratamentos com água eletrolisada oxidante e redutora foram aplicados por 1, 3 e 6 minutos. Por outro lado, as sementes foram infectadas com cada uma das cepas bacterianas de forma independente e foram aplicados tratamentos com água eletrolisada. Os resultados mostram que a água oxidante é mais eficiente como agente antimicrobiano, pois conseguiu uma redução de 100% no crescimento das duas cepas bacterianas após um minuto de tratamento. Os tratamentos não afetaram a porcentagem de germinação, pois em todos os tratamentos obtiveram-se porcentagens de germinação acima de 90% e as plântulas não foram afetadas em nenhuma das variáveis estudadas.
Assuntos
Germinação , Pseudomonas syringae , Eletrólise , Clavibacter , AntibacterianosRESUMO
Since the fruits of Bromelia pinguin and Bromelia karatas are rich in proteases, the aim of this research was to optimize the hydrolysis process of cooked white shrimp by-products due to the effect of these proteases. A robust Taguchi L16' design was used to optimize the hydrolysis process. Similarly, the amino acid profile by GC-MS and antioxidant capacity (ABTS and FRAP) were determined. The optimal conditions for hydrolysis of cooked shrimp by-products were pH 8.0, 30 °C, 0.5 h, 1 g of substrate and 100 µg/mL of B. karatas, pH 7.5, 40 °C, 0.5 h, 0.5 g substrate and 100 µg/mL enzyme extract from B. pinguin and pH 7.0, 37 °C, 1 h, 1.5 g substrate and 100 µg/mL enzyme bromelain. The optimized hydrolyzates of B. karatas B. pinguin and bromelain had 8 essential amino acids in their composition. The evaluation of the antioxidant capacity of the hydrolyzates under optimal conditions showed more than 80% inhibition of in ABTS radical, B. karatas hydrolyzates had better higher ferric ion reduction capacity with 10.09 ± 0.02 mM TE/mL. Finally, the use of proteolytic extracts from B. pinguin and B. karatas to optimize hydrolysis process allowed obtaining hydrolyzates of cooked shrimp by-products with potential antioxidant capacity.
RESUMO
BACKGROUND: Ultraviolet B (UVB) causes photoaging of the skin, the appearance of wrinkles, spots, and alteration of the skin barrier. The main cells in the most superficial layer of the skin are the keratinocytes; these cells play an important role in protecting this organ. OBJECTIVE: The present study aimed to investigate the antioxidant activity of the hydrolysates from kafirin to inhibit UVB-induced responses in human keratinocytes cells (HaCaT). METHODS: Kafirin hydrolysates were produced by enzymatic hydrolysis with alcalase. The activity of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx), in the HaCaT cell line in the presence of UVB and the effects of the hydrolysates against the UVB-induced response were evaluated. Furthermore, the peptides that were generated by hydrolysis were identified in silico using the BIOPEP database. RESULTS: Two protein sequences were identified (α-kafirin and the precursor protein of α-kafirin), in the kafirin extract. A degree of hydrolysis of 18.8% was obtained by hydrolyzing the kafirin extract with alcalase. The kafirin hydrolysates avoided the decrease in endogenous antioxidant enzymes such as SOD, CAT, and GPx reducing the oxidative stress generated by UVB. Using the BIOPEP-UWM database, we found 102 peptide sequences, and it has shown that the peptides have a large amount of hydrophobic amino acids such as proline, alanine, and glutamine, and amino acids with high antioxidant capacity. CONCLUSION: These results suggest that the kafirin hydrolysates can be used as antioxidant agents to ameliorate UVB-induced skin keratinocytes cells' response in vitro, providing an alternative against UVB-induced photoaging.
Assuntos
Antioxidantes , Queratinócitos , Humanos , Antioxidantes/farmacologia , Antioxidantes/química , Queratinócitos/metabolismo , Peptídeos/farmacologia , Peptídeos/química , Peptídeos/metabolismo , Superóxido Dismutase/metabolismo , Aminoácidos/metabolismo , Aminoácidos/farmacologia , Raios Ultravioleta/efeitos adversosRESUMO
The objective of this work was to find the optimal conditions by thermosonication-assisted extraction (TSAE) of the total acetogenin content (TAC) and yield from A. muricata seeds, assessing the effect of the temperature (40, 50, and 60 °C), sonication amplitude (80, 90, and 100%), and pulse-cycle (0.5, 0.7, and 1 s). In addition, optimal TSAE conditions of acetogenins (ACGs) were compared with extraction by ultrasound at 25 °C and the soxhlet method measuring TAC and antioxidant capacity. Moreover, solubility and identification of isolated ACGs were performed. Furthermore, the antifungal activity of ACGs crude extract and isolated ACGs was evaluated. Optimal TSAE conditions to extract the highest TAC (35.89 mg/g) and yield (3.6%) were 50 °C, 100% amplitude, and 0.5 s pulse-cycle. TSAE was 2.17-fold and 15.60-fold more effective than ultrasound at 25 °C and the Soxhlet method to extract ACGs with antioxidant capacity. Isolated ACGs were mostly soluble in acetone and methanol. Seven ACGs were identified, and pseudoannonacin was the most abundant. The inhibition of Candida albicans, Candida krusei, and Candida tropicalis was higher from isolated ACGs than crude extract. TSAE was effective to increase the yield in the ACGs extraction from A. muricata seeds and these ACGs have important antifungal activity.
Assuntos
Annona , Acetogeninas/farmacologia , Acetona , Antifúngicos/farmacologia , Antioxidantes/farmacologia , Metanol , Extratos Vegetais/farmacologia , SementesRESUMO
Anthracnose is a fungal disease caused by Colletotrichum species that is detrimental to numerous fruit, including soursop and avocado. The use of fungicides to maintain the high quality of fruit creates a potential health risk. One alternative to this problem is the biological control, which has been applied successfully during postharvest. The Bacillus species are one of the most studied biological agents against postharvest pathogens because accomplish their biocontrol performance by producing a variety of metabolites. In this study, we evaluated the activity of metabolites contained in the cell free supernatant, obtained from Bacillus strain B5 culture, against micelial growth and spore germination of two virulent strains of C. gloeosporioides isolated from soursop and avocado. On the basis of 16S rDNA gene sequence analysis, this strain was identified as Bacillus atrophaeus. A preventive treatment using cell free supernatant, reduced severity and incidence of anthracnose disease on harvested soursop and avocado fruit. B. atrophaeus strain B5 harbors genes involved in the production of antibiotics such as surfactin, bacillomycin and iturin, which could be contributing to the efficiency of the preventive treatment during postharvest. The antagonistic role of metabolites contained in the cell free supernatant against anthracnose disease, provide a new approach by which to attack this problem and can help reduce the use of chemical pesticides, environmental pollution, leading to the safer fruit preservation.
Assuntos
Annona/microbiologia , Bacillus/fisiologia , Agentes de Controle Biológico/farmacologia , Colletotrichum/efeitos dos fármacos , Persea/microbiologia , Doenças das Plantas/microbiologia , Doenças das Plantas/prevenção & controle , Annona/efeitos dos fármacos , Annona/crescimento & desenvolvimento , Antibiose , Bacillus/classificação , Bacillus/genética , Bacillus/isolamento & purificação , Colletotrichum/crescimento & desenvolvimento , Colletotrichum/patogenicidade , DNA Ribossômico/genética , Frutas/efeitos dos fármacos , Frutas/microbiologia , Fungicidas Industriais , Genes Bacterianos/genética , Lipopeptídeos/genética , Lipopeptídeos/farmacologia , México , Testes de Sensibilidade Microbiana , Micélio/efeitos dos fármacos , Micélio/crescimento & desenvolvimento , Peptídeos/genética , Peptídeos/farmacologia , Peptídeos Cíclicos/genética , Peptídeos Cíclicos/farmacologia , Persea/efeitos dos fármacos , Persea/crescimento & desenvolvimento , Filogenia , Análise de Sequência , Esporos Fúngicos/efeitos dos fármacos , Esporos Fúngicos/crescimento & desenvolvimentoRESUMO
Avocado (Persea americana) is one of the most important crops in Mexico as it is the main producer, consumer, and exporter of avocado fruit in the world. However, successful avocado commercialization is often reduced by large postharvest losses due to Colletotrichum sp., the causal agent of anthracnose. Chitosan is known to have a direct antifungal effect and acts also as an elicitor capable of stimulating a defense response in plants. However, there is little information regarding the genes that are either activated or repressed in fruits treated with chitosan. The aim of this study was to identify by RNA-seq the genes differentially regulated by the action of low molecular weight chitosan in the avocado-chitosan-Colletotrichum interaction system. The samples for RNA-seq were obtained from fruits treated with chitosan, fruits inoculated with Colletotrichum and fruits both treated with chitosan and inoculated with the fungus. Non-treated and non-inoculated fruits were also analyzed. Expression profiles showed that in short times, the fruit-chitosan system presented a greater number of differentially expressed genes, compared to the fruit-pathogen system. Gene Ontology analysis of differentially expressed genes showed a large number of metabolic processes regulated by chitosan, including those preventing the spread of Colletotrichum. It was also found that there is a high correlation between the expression of genes in silico and qPCR of several genes involved in different metabolic pathways.