Browsing by Autor "Benitez-Ahrendts, Marcelo Rafael"

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Fungal microbiota isolated from native stingless bee species inhibited pathogens of Apis mellifera.
(2023) Tejerina, Marcos Raúl; Cabana, María José; Cruz, Nancy Marina; Enríquez, Pablo Adrián; Benitez-Ahrendts, Marcelo Rafael; Fonseca, María Isabel
Social bees can establish interactions with microorganisms to keep their colonies free of pathogens and parasites by developing different protection strategies. We explored the fungal microbiota isolated from three species of stingless bees, Tetragonisca fiebrigi, Plebeias sp., and Scaptotrigona jujuyensis, and its potential ability to suppress pathogenic microorganisms of A. mellifera, namely Paenibacillus larvae, Ascosphaera apis and Aspergillus flavus, which were tested and evaluated. Six filamentous fungal strains, Trametes hirsuta, Alternaria alternata, Curvularia spicifera, Skeletocutis sp., Alternaria tenuissima, Monascus spp., as well as the yeast Wickerhamomyces anomalus, were selected for trials and isolated from the heads of foraging bees. The fungal strains were identified by macroscopic and microscopic taxonomic characteristics and by sequencing of the ITS1-5.8S-ITS2 region of ribosomal DNA. All fungal strains inhibited these pathogens of A. mellifera. We also evaluated the effect of the secondary metabolites extracted with and without ethanol. Both metabolites showed antimicrobial properties, and our results suggest that fungi isolated from stingless bees produce bioactive compounds with antibacterial and antifungal effects that could be used to treat Apis mellifera colony diseases and maintain colony health.
Strains of Lactobacillus spp. reduce chalkbrood in Apis mellifera.
(2021) Tejerina, Marcos Raúl; Cabana, María José; Benitez-Ahrendts, Marcelo Rafael
Beekeeping activities have increased recently in Argentina, a country that is a major consumer of honey and other products from hives. With the advancement of monoculture areas in Argentina and worldwide, beekeepers move from one area to another in search of floral resources, thus spreading diseases such as chalkbrood, caused by the fungus Ascosphaera apis. Although there are few effective antifungals for the control of chalkbrood, different natural products have been investigated in recent years. Current research is focusing on the intestinal microbiota for the prevention of different pathogens and parasites. In this work, we analyzed the in vivo probiotic effect of three lactic acid bacteria (genus Lactobacillus spp.) isolated from pollen bread from apiaries of Jujuy province on A. apis strains from Spanish and Argentine provinces. Special hives were made for the assays, and a protective effect was observed in larvae of bees fed lactic acid bacteria added to sugar syrup at 105 CFU/mL concentrations, administered from May to September in two consecutive years. The results showed that the three lactic acid bacteria reduced larval mummification by percentages greater than 80%. Therefore, this work brings a first approximation of the in vivo probiotic effect of lactic bacteria against A. apis.