Search

SummaryRoyal jelly (RJ) is secreted by worker bees of Apis mellifera to feed the queen larvae. Believed to be the longevity factor of queen honey bees and due to its variety of health promoting ingredients, RJ is used worldwide as dietary supplement, health product and in cosmetics. To reach best possible effects, application of high quality RJ is absolutely required. Here we show, based on physicochemical properties and antioxidant activity, a comparison between fresh, local RJ samples obtained directly from beekeepers and commercial ones. Analyses revealed a higher content of 10-hydroxy-2-decenoic acid, a quality parameter of RJ, for local compared to commercial RJ. Furthermore, determined ferric reducing antioxidant power (FRAP) correlated with radical scavenging activity (DPPH) and total polyphenols was significantly higher in local RJ samples. Therefore, our results indicate a higher quality for local RJ compared to commercial.

In vitro amyloid formation has been suggested to be a common property of any polypeptide chain depending on particular environmental conditions although in vivo amyloid fibril formation can be promoted by point mutations or triplet expansions. Here, we explored the influence of agitation on fibril formation of amyloidogenic alanine segments fused to Cold Shock Protein B (CspB) of Bacillus subtilis. While without agitation fibril formation was clearly dependent on the presence of an amyloidogenic alanine segment, fibril formation was independent of the amyloidogenic segment under agitation. Agitation even led to fibrillation of native CspB lacking the amyloidogenic segment. Furthermore, agitation not only influenced the kinetics of fibril formation, but also resulted in completely different fibril morphologies. These results indicate that experimental conditions can alter the region that undergoes a conformational change during in vitro fibrillation. Moreover, the data show that deductions from in vitro assays on in vivo fibril formation mechanisms are afflicted with a certain degree of uncertainty and therefore need to be cautiously discussed.