Márcia Ebling de Souza

Fungal Infections In Honey Bees

The apiculture is very important to the international agroindustry, due to the fact that bees are responsible for thehighest percentage of plant pollination of human food. However currently the bee keepers are facing troubles due the loss of Apis mellifera colonies causing losses to the honey production and mainly to the pollination of important agricultural cultures in the world and the impacts in food security. The decline of these pollinators can be explained by the many factors like, bad nutrition, loss of the queen and many pathogens and parasites. Stonebrood is a disease caused by the fungal Aspergillus through the ingest of spores and through the scarf-skin, therefore, can infect larvae and adult bees. Other pathology is the Chalkbrood, an infection disease caused by the fungal Ascosphaera apis, that occurs in bee larvaes (A. mellifera) is usually more prevalent in the spring, since it the growth is enhanced in cool and damp place. In recent years many researches were performed using many chemotherapeutic and chemical products looking for any alternative to the treatment of Chalkbrood, but none of these studies obtained positive results. Some strategies have been used by the beekeepers to try to control the Stonebroodand Chalkbrood like: management and sanitation practices (include a food supplementation, to improve the health of bees, keeping the hive clean and ventilated, and preventing transfer of the pests between colonies); use of natural products and ecological safety. Is important prevent the use of synthetic pesticides because can impact in bee health and make the honey inappropriate to the consume.

Melaleuca alternifolia Essential Oil against the Lesser Mealworm (Alphitobius diaperinus) and Its Possible Effect on the Soil Fauna

The aim of this study was to evaluate the in vitro bioactivity of tea tree (Melaleuca alternifolia) essential oil against larvae and adult forms of lesser mealworms (Alphitobius diaperinus) and its influence on the soil fauna. Tests were performed in triplicate using pure tea tree oil (TTO; 1, 5, 10, 25, 50, and 100%), TTO nanoparticles (1, 3, and 7.5%), or terpinen-4-ol, the main compound of the tea tree oil, at the same concentrations of TTO. Larvae and adult mortality occurred at concentrations up to 10 and 50% of TTO, respectively. No larvicidal or insecticidal effect of TTO nanoparticles was observed. Terpinen-4-ol showed insecticidal and larvicidal effect at concentrations higher than 25%. The evaluation of TTO effect on soil organisms was performed by standard ecotoxicological tests (ISO) with the springtail species Folsomia candida. Only TTO was used for ecotoxicological tests in doses of 1, 5, 10, 25, 50, and 100 mg kg-1 of soil. TTO had no negative effects on F. candida survival or reproduction. Therefore, it was concluded that M. alternifolia oil may be a new alternative for control of the lesser mealworm.

Nanoemulsions containing Cymbopogon flexuosus essential oil: Development, characterization, stability study and evaluation of antimicrobial and antibiofilm activities

The increase of microbial resistance generates the search for new substances with antimicrobial potential. The essential oil of Cymbopogon flexuosus (Lemongrass) stands out in the literature for its antimicrobial, insecticide and antioxidant properties, but it has high volatilization and low stability, and the nanoencapsulation of this oil could be an alternative to overcome these limitations. Thus, the objective of this study was to develop, for the first time, nanoemulsions containing the essential oil of C. flexuosus, through a method that does not use organic solvent and with temperature control to avoid the volatilization of the oil, characterize and evaluate of stability and the antimicrobial and antibiofilm activities of these nanoemulsions. Nanoemulsions presented adequate physicochemical characteristics (average size less than 200 nm, polydispersity index less than 0.3, negative zeta potential and acid pH) which were maintained during 90 days of storage, and the nanoencapsulation of the C. flexuosus oil enhanced its therapeutic efficacy against the microorganisms evaluated in this study compared to the free oil. These results are very promising because among the microorganisms that the nanoemulsion containing C. flexuosus was able to inhibit the formation of biofilm are the bacteria Pseudomonas aeruginosa and Staphylococcus aureus, which were recently listed by the World Health Organization as priority pathogens for development of new antibiotics.