RESUMO
The aim of this work was to compare the antimicrobial activity against Paenibacillus larvae and the antioxidant capacity of two Laurus nobilis L. extracts obtained by different extraction methods. The hydroalcoholic extract was moreover added as supplementary diet to bees in field conditions to test behavioural effects and colony strength. Both laurel extracts were subjected to different phytochemical analysis to identify their bioactive compounds. Antimicrobial activity was analyzed by the minimal inhibitory concentration (MIC) determination by means the agar dilution method. The hydroalcoholic extract (HE) was able to inhibit the bacterial growth of all P. larvae strains, with 580⯵g/mL mean value. This better antibacterial activity in relation to the essential oil (EO) could be explained by the presence of some phenolic compounds, such as flavonoids, evidenced by characteristic bands resulting from the Fourier Transform Infrared Spectroscopy (FTIR) analysis. Antioxidant activities of the extracts were evaluated by 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical-scavenging ability and ferric reducing antioxidant power (FRAP) assays. The HE showed the highest antioxidant activity as measured by DPPH, with IC50 values of 257⯱â¯12⯵g/mL. The FRAP assay method showed that the HE was 3-fold more effective reducing agent than the EO. When the bee colonies were supplied with laurel HE in sugar paste an improvement in their general condition was noticed, although neither the hygienic behavior nor the proportions of the breeding cells varied statistically due to the treatment. In conclusion, the inhibition power against P. larvae attributable to the phenolic compounds, the antioxidant capacity of the HE, and the non-lethal effects on adult honey bees on field trials suggest the HE of laurel as a promising substance for control American foulbrood disease.
RESUMO
Abstract The relative size of the Aristotle's lantern of most sea urchins varies in relation to the food availability and it is often used to infer the availability of food of the environment. The aim of our study was to evaluate the lantern morphology plasticity of Arbacia dufresnii in populations with different environmental characteristics, either mussel beds or disturbed areas, by the invasive alga Undaria pinnatifida along the Patagonian Atlantic coast. The test diameter of the sea urchins along with the weight and height of the lanterns, the jaw lenght and rotula lenght were measured. Classic and geometric morphometric analyses were performed to test differences among populations. The length of the jaw was the best indicator of relative changes in size of the lantern. The largest length of the jaw was measured in individuals from disturbed areas dominated by the invasive algae U. pinnatifida. The rotula shape changed with the increase of the diameter of the sea urchins, it tends to be more elongated with larger sea urchins. Rev. Biol. Trop. 63 (Suppl. 2): 339-351. Epub 2015 June 01.
Resumen El tamaño relativo de la linterna de Aristóteles en la mayoría de las especies de erizos de mar varía en relación con la disponibilidad de alimentos y se utiliza a menudo para inferir la disponibilidad de alimentos en el medio ambiente en que los erizos de mar habitan. El objetivo de este estudio fue evaluar la plasticidad morfológica de la linterna de Aristóteles de Arbacia dufresnii en poblaciones con diferentes características ambientales, ya sean con bancos de mejillones o áreas modificadas por el alga invasora Undaria pinnatífida, a largo de la costa patagónica atlántica. Se midió el diámetro del caparazón, el peso y el alto de las linternas, la longitud de la semipirámide y la longitud de la rótula. Los datos se analizaron utilizando técnicas de morfometría clásica y geométrica con el objetivo de probar diferencias entre las poblaciones. La longitud de la semipirámide fue el mejor indicador para describir los cambios relativos en el tamaño de la linterna. La mayor longitud de la semipirámide se observó en las poblaciones que habitan áreas dominadas por el alga invasora U. pinnatifida. La forma de la semipirámide no varía entre las poblaciones ni con el tamaño de los erizos de mar, mientras que la forma de la rótula cambia en relación al tamaño de los erizos, siendo más alargada cuando el tamaño de los individuos es mayor.
