RESUMEN
Fungi represent a group of eukaryotic microorganisms that are an important part of the plant microbiome. They produce a vast array of metabolites, including fungal volatile organic compounds (fVOCs). However, the diversity and biological activities of fVOCs emitted by the mycobiota of plants native to arid and semi-arid environments remain under-explored. We characterized the chemical diversity of fVOCs produced by 22 representative members of the microbiome of agaves and cacti using SPME-GC-MS. We further tested the effects of pure compounds on the growth and development of Arabidopsis thaliana and host plants. Members of the Sordariomycetes (nine strains), Eurotiomycetes (three), Dothideomycetes (eight), Saccharomycetes (one) and Mucoromycetes (one) were included in our study. We identified 94 fungal organic volatiles classified into nine chemical classes. Terpenes showed the greatest chemical diversity, followed by alcohols and aliphatic compounds. We discovered that camphene and benzyl benzoate, together with the widely distributed and already tested benzyl alcohol, 2-phenylethyl alcohol and 3-methyl-1-butanol, improved plant growth and development of A. thaliana, Agave tequilana and Agave salmiana. Our studies on the fungal VOCs from desert plants underscore an untapped chemical diversity with promising biotechnological applications.
Asunto(s)
Arabidopsis , Ascomicetos , Microbiota , Compuestos Orgánicos Volátiles , Desarrollo de la PlantaRESUMEN
AIMS: Identify novel bacterial taxa that could increase the availability of branched-chain amino acids and the amount of distinctive volatiles during skim milk fermentation. METHODS AND RESULTS: We recovered 344 bacterial isolates from stool samples of healthy and breastfed infants. Five were selected based on their ability to produce branched-chain amino acids. Three strains were identified as Escherichia coli, one as Klebsiella pneumoniae and other as Klebsiella variicola by molecular and biochemical methods. HPLC and solid-phase microextraction with GC-MS were used for the determination of free amino acids and volatile compounds respectively. The consortium formed by K. variicola and four Lactobacillus species showed the highest production of Leu and Ile in skim milk fermentation. In addition, the production of volatile compounds, such as acetoin, ethanol, 2-nonanone, and acetic, hexanoic and octanoic acids, increased in comparison to commercial yogurt, Emmental and Gouda cheese. Also, distinctive volatiles, such as 2,3-butanediol, 4-methyl-2- hexanone and octanol, were identified. CONCLUSION: The use of K. variicola in combination with probiotic Lactobacillus species enhances the availability of Leu and Ile and the amount of distinctive volatiles during skim milk fermentation. SIGNIFICANCE AND IMPACT OF THE STUDY: The identified consortium increases the functional potential of fermented dairy products.
Asunto(s)
Aminoácidos de Cadena Ramificada/metabolismo , Productos Lácteos Cultivados/microbiología , Klebsiella/metabolismo , Lactobacillus/metabolismo , Compuestos Orgánicos Volátiles/metabolismo , Animales , Butileno Glicoles/metabolismo , Bovinos , Queso , Fermentación , Cetonas/metabolismo , Consorcios Microbianos , Leche/microbiología , Probióticos/metabolismo , Yogur/microbiologíaRESUMEN
Enamel resistance to acid dissolution is a factor which has an influence upon dental caries susceptibility. The objectives of this study were to determine enamel resistance to acid dissolution by applying the RM technique, and to correlate data obtained to the prevalence of dental caries. Two hundred and seventy one children between seven and nine years of age were chosen by non probabilistic sampling in two city districts, (six public schools in Mexico City). These children's central permanent incisives had already erupted. The DMF-T and dmf-t indexes were recorded, and the RM enamel resistance test was performed on them. A total of 56.4% of the subjects in the sample had very resistant enamel and 27.3%, less resistant enamel. A proportion of 57.9% was free of dental caries on the permanent dentition and 10% in the temporary dentition. The average obtained for the DMF-T index was 0.93 +/- 1.34 and that for dmf-t was 4.7 +/- 3.1. Data suggest that enamel resistance distribution is not homogeneous and this increases proportionally in relation to the eruption third (p < 0.05.) Spearman's correlation coefficient was found to be negative and statistically significant at p < 0.05. The RM technique showed the presence of individuals with different enamel resistance to acid dissolution.