Evaluation of the phytosanitary, fermentative and nutritive characteristics of the silage made from crude artichoke (Cynara scolymus L.) by-product feeding for ruminants

The crude by-product left after industrial processing of artichoke (Cynara scolymus L.) was ensiled in microsilos and sampled at different times. To evaluate its suitability as animal feed, various fermentative, chemical and phytosanitary parameters were determined. The by-product showed a good aptitude for ensilage, having a pleasant smell and good visual characteristics. The DM content was 297 g kg⁻¹, and no effluents were detected. It stabilized after 12 days of ensiling and showed a pH value of 4.1 at the end of the process. Only small losses were detected in its chemical value after the ensiling period. Prometryn was the only phytosanitary product found at day 0 (0.04 ppm a concentration below the maximum amount permitted by law), but was not detected after 12 days of ensilage. It is concluded that the silage by-product can be used as animal feed.     

Cytotoxicity of pilosulin 1, a peptide from the venom of the jumper ant Myrmecia pilosula

The synthetic peptide pilosulin 1, corresponding to the largest defined allergenic polypeptide found in the venom of the jumper ant Myrmecia pilosula, inhibited the incorporation of [methyl-³H]thymidine into proliferating Epstein–Barr transformed (EBV) B-cells. The LD₅₀ was four-fold lower in concentration than melittin, a cytotoxic peptide found in honey bee venom. Loss of cell viability was assessed by flow cytometry by measuring the proportion of cells that fluoresced in the presence of the fluorescent dye 7-aminoactinomycin D. Examination of proliferating EBV B-cells indicated that the cells lost viability within a few minutes exposure to pilosulin 1. Partial peptides of pilosulin 1 were less efficient in causing loss of cell viability and the results suggest that the 22 N-terminal residues are critical to the cytotoxic activity of pilosulin 1. Normal blood white cells were also labile to pilosulin 1. T- and B-lymphocytes, monocytes and natural killer cells, however, were more labile than granulocytes. Analysis of pilosulin 1 using circular dichroism indicated that, in common with melittin and other Hymenoptera venom toxins, it had the potential to adopt an α-helical secondary structure.