Browsing by Author "Fuselli, Sandra"

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    Immune-related gene expression in honey bee larva (Apis mellifera) exposed to plant extracts from Humulus lupulus with antimicrobial activity against Paenibacillus larvae
    (2021) Giménez-Martínez, Pablo; Zuñiga, Fabián; Junges, Celina; Maggi, Matías; Fuselli, Sandra; Martínez, Jessica
    American foulbrood caused by Paenibacillus larvae brings with it several problems on beekeepers for the use of synthetic antibiotics, likewise led to the appearance of resistant strains and the presence of chemical residues in the commercial products of the hive. In recent years, the use of natural compounds for the control of P. larvae has increased. Herein, we propose to determine the value of the Minimal Inhibitory Concentration (MIC) of a hydroalcoholic extract of Humulus lupulus (hop) leaves of Victoria variety on P. larvae strain, and to evaluate its toxicity and effect on the expression of three genes of the immune system on honey bee larvae. For the extract, the MIC value was 83.79 μg/mL. For larvae, the extract did not show toxicity, on the other hand presented a down-regulation in the gene expression for the three genes evaluated. The results obtained here are a first report on the evaluation in the effect of natural extracts on the expression of genes related to the immune system in bee larvae.
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    Spent coffee grounds extract: antimicrobial activity against Paenibacillus larvae and its effect on the expression of antimicrobial peptides in Apis mellifera
    (2023) Giménez, Pablo; Zúñiga, Fabián; Medici, Sandra; Fuselli, Sandra; Martinez Arenas, Jessica Isabel
    In recent years, natural alternatives have been sought for the control of beekeeping pathologies; in the case of American Foulbrood (AFB) disease, the use of synthetic antibiotics was prohibited due to honey contamination and the generation of resistant bacteria. The significant increase in population growth worldwide has led to great concern about the production of large amounts of waste, including those from agribusiness. Among the most important beverages consumed is coffee, generating thousands of tons of waste called spent coffee grounds (SCG). The SCG is a source of many bioactive compounds with known antimicrobial activity. The aims of the present work were: (1) to obtain and chemically analyse by HPLC of SCG extracts (SCGE), (2) to analyse the antimicrobial activity of SCGE against vegetative form of Paenibacillus larvae (the causal agent of AFB), (3) to evaluate the toxicity in bees of SCGE and (4) to analyse the effect of the extracts on the expression of various genes of the immune system of bees. SCGs have a high content of phenolic compounds, and the caffeine concentration was of 0.3%. The MIC value obtained was 166.667 µg/mL; the extract was not toxic to bees, and interestingly, overexpression of abaecin and hymenoptaecin peptides was observed. Thus, SCGE represents a promising alternative for application in the control of American Foulbrood and as a possible dietary supplement to strengthen the immune system of honeybees. Therefore, the concept of circular bio-economy could be applied from the coffee industry to the beekeeping industry.

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