The human amylin is a pancreatic peptide hormone found in hyperhormonemic state along with insulin in subclinical diabetes. Amylin has been associated with the pathology of type 2 diabetes, particularly due to its ability to assembly into toxic oligomers and amyloid specimens. On the other hand, some variants such as murine amylin has been described as non-amyloidogenic, either in vitro or in vivo. Recent data have demonstrated the amyloid propensity of murine amylin and the therapeutic analogue pramlintide, suggesting a universality for amylin amyloidosis. Here, we report the amyloidogenesis of murine amylin, which showed lower responsivity to the fluorescent probe thioflavin T compared to human amylin, but presented highly organized fibrilar amyloid material. The aggregation of murine amylin also resulted in the formation of cytotoxic specimens, as evaluated in vitro in INS-1 cells. The aggregation product from murine amylin was responsive to a specific antibody raised against amyloid oligomers, the A11 oligomer antibody. Pancreatic islets of wild-type Swiss male mice have also shown responsivity for the anti-oligomer, indicating the natural abundance of such specimen in rodents. These data provide for the first time evidences for the toxic nature of oligomeric assemblies of murine amylin and its existence in wild-type, non-transgenic mice.

Mistletoes are parasitic plants that penetrate the host branches through a modified root and connect to their xylem to acquire nutrients and water. Under mistletoe infection, resources that would otherwise be used by the host are stolen by the parasite. Our aim was to compare leaf morpho-physiological traits between healthy uninfected branches and mistletoe-infected branches of a Neotropical tree species (Handroanthus chrysotrichus (Mart. ex DC.) Mattos – Bignoniaceae). We also investigated differences between mistletoe and host leaf traits. Morphological (petiole length and thickness, leaf area and thickness, and specific leaf area) and physiological leaf traits (pre-dawn and midday water potential) were measured in 10 individuals infected with the mistletoe Phoradendron affine (Pohl ex DC.) Engl. & K.Krause (Santalaceae). Mistletoes showed smaller and thicker leaves with lower pre-dawn and midday water potential, suggesting that mistletoes are more profligate water users than the host. Host leaves from infected branches were scleromorphic and showed stronger water-use control (less negative water potential) than host leaves from uninfected branches. Our results indicated that leaves from infected branches shifted to a more conservative resource-use strategy as a response to a water and nutrient imbalance caused by mistletoe infection.

Polymerization through reversible addition-fragmentation chain-transfer (RAFT) polymerization has been extensively employed for the production of polymers with controlled molar mass, complex architectures and copolymer composition distributions intended for biomedical and pharmaceutical applications. In the present work, RAFT miniemulsion copolymerizations of methyl methacrylate with acrylic acid and methacrylic acid were conducted to prepare hydrophilic polymer nanoparticles and compare cell uptake results after bioconjugation with bovine serum albumin (BSA), used as a model biomolecule. Obtained results indicate that the RAFT agent 2-cyano-propyl-dithiobenzoate allowed for successful free radical controlled methyl methacrylate copolymerizations and performed better when methacrylic acid was used as comonomer. Results also indicate that poly(methyl methacrylate-co-methacrylic acid) nanoparticles prepared by RAFT copolymerization and bioconjugated with BSA were exceptionally well accepted by cells, when compared to the other produced polymer nanoparticles because cellular uptake levels were much higher for particles prepared in presence of methacrylic acid, which can probably be associated to its high hydrophilicity.

The human amylin is a pancreatic peptide hormone cosecreted with amylin and found in hyperhormonemic state along with insulin in subclinical diabetes. Amylin has been associated with the pathology of type 2 diabetes, particularly due to its ability to assembly into toxic oligomers and amyloid speciments. On the other hand, some variants such as murine amylin has been described as non amyloidogenic, either in vitro or in vivo. Recent data have demonstrated the amyloid propensity of murine amylin and the therapeutic analogue pramlintide, suggesting a universality for amylin amyloidosis. Here we report the amyloidogenesis of murine amylin, which showed lower responsivity to the fluorescent probe thioflavin T compared to human amylin, but presented highly organized fibrilar amyloid material. The aggregation of murine amylin also resulted in the formation of cytotoxic specimens, as evaluated in vitro in INS-1 cells.The aggregation product from murine amylin was responsive to a specific antibody raised against amyloid oligomers, the A11 oligomer antibody. Pancreatic islets of swiss mice have also shown responsivity for the anti-oligomer, indicating the natural abundance of such specimen in rodents. These data provide for the first time evidences for the toxic nature of oligomeric assemblies of murine amylin and its existence in non-transgenic mice. Highlights:-Murine amylin forms oligomer species and amyloid fibrils in vitro -The murine amylin aggregation product display cellular toxicity -A11 anti-oligomer antibody recognizes murine amylin in vitro -Non-transgenic mice display immunoresposivity to anti-oligomer in pancreatic islet peer-reviewed)