This research effort aimed at isolating and phenotypically characterizing lactic acid bacteria (LAB) isolates from a spontaneous rye sourdough manufactured following traditional protocols, as well as at evaluating their antimicrobial and antifungal properties as key features for future industrial applications. Thirteen LAB strains of potential industrial interest were isolated and identified to species-level via PCR. Most of the sourdough isolates showed versatile carbohydrate metabolisms. The Leuconostoc mesenteroides No. 242 and Lactobacillus brevis No. 173 demonstrated to be gas producers; thus, revealing their heterofermenter or facultative homofermenter features. Viable counts higher than 7.0 log10 (CFU/mL) were observed for Lactobacillus paracasei No. 244, Lactobacillus casei No. 210, L. brevis No. 173, Lactobacillus farraginis No. 206, Pediococcus pentosaceus No. 183, Lactobacillus uvarum No. 245 and Lactobacillus plantarum No. 135 strains, after exposure at pH 2.5 for 2 h. Moreover, L. plantarum No. 122, L. casei No. 210, Lactobacillus curvatus No. 51, L. paracasei No. 244, and L. coryniformins No. 71 showed growth inhibition properties against all the tested fifteen pathogenic strains. Finally, all LAB isolates showed antifungal activities against Aspergillus nidulans, Penicillium funiculosum, and Fusarium poae. These results unveiled the exceptionality of spontaneous sourdough as a source of LAB with effective potential to be considered in the design of novel commercial microbial single/mixed starter cultures, intended for application in a wide range of agri-food industries, where the antimicrobial and antifungal properties are often sought and necessary. In addition, metabolites therefrom may also be considered as important functional and bioactive compounds with high potential to be employed in food and feed, as well as cosmetic and pharmaceutical applications.

Background Avian infectious bronchitis (IB) is a disease that can result in huge economic losses in the poultry industry. The high level of mutations of the IB virus (IBV) leads to the emergence of new serotypes and genotypes, and limits the efficacy of routine prevention. Medicinal plants, or substances derived from them, are being tested as options in the prevention of infectious diseases such as IB in many countries. The objective of this study was to investigate extracts of 15 selected medicinal plants for anti-IBV activity. Results Extracts of S. montana , O. vulgare , M. piperita , M. officinalis , T. vulgaris , H. officinalis , S. officinalis and D. canadense showed anti-IBV activity prior to and during infection, while S. montana showed activity prior to and after infection. M. piperita , O. vulgare and T. vulgaris extracts had > 60 SI. In further studies no virus plaques (plaque reduction rate 100%) or cytopathogenic effect (decrease of TCID 50 from 2.0 to 5.0 log 10 ) were detected after IBV treatment with extracts of M. piperita , D. canadense and T. vulgaris at concentrations of extracts ≥0.25 cytotoxic concentration (CC 50 ) ( P < 0.05). Both PFU number and TCID 50 increased after the use of M. piperita , D. canadense , T. vulgaris and M. officinalis extracts, the concentrations of which were 0.125 CC 50 and 0.25 CC 50 ( P < 0.05). Real-time PCR detected IBV RNA after treatment with all plant extracts using concentrations of 1:2 CC 50 , 1:4 CC 50 and 1:8 CC 50 . Delta cycle threshold (Ct) values decreased significantly comparing Ct values of 1:2 CC 50 and 1:8 CC 50 dilutions ( P < 0.05). Conclusions Many extracts of plants acted against IBV prior to and during infection, but the most effective were those of M. piperita , T. vulgaris and D. canadense .

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Machine learning methods identify antiviral phytochemicals using CART decision trees.