ALBERT

Description: Solitary foraging ants have a navigational toolkit, which includes the use of both terrestrial and celestial visual cues, allowing individuals to successfully pilot between food sources and their nest. One such celestial cue is the polarization pattern in the overhead sky. Here, we explore the use of polarized light during outbound and inbound journeys and with different home vectors in the nocturnal bull ant, Myrmecia midas . We tested foragers on both portions of the foraging trip by rotating the overhead polarization pattern by ±45°. Both outbound and inbound foragers responded to the polarized light change, but the extent to which they responded to the rotation varied. Outbound ants, both close to and further from the nest, compensated for the change in the overhead e-vector by about half of the manipulation, suggesting that outbound ants choose a compromise heading between the celestial and terrestrial compass cues. However, ants returning home compensated for the change in the e-vector by about half of the manipulation when the remaining home vector was short (1–2 m) and by more than half of the manipulation when the remaining vector was long (more than 4 m). We report these findings and discuss why weighting on polarization cues change in different contexts.

Description: Xuanwei ham is especially rich in a large amount of peptides and free amino acids under the action of protein degradation. Some of these peptides can potentially exert bioactivities of interest for human health. Traditionally, Xuanwei ham should undergo Chinese household cooking treatments before eating. However, it has not been known how its bioactivity changes after cooking and gastrointestinal digestion. Herein, Xuanwei ham is analysed before and after cooking, as well as gastrointestinal digestion being simulated so as to evaluate and compare its effect on antioxidant and angiotensin I-converting enzyme (ACE) inhibitory activities. The antioxidant activity is analysed using five different methods, and results demonstrate that cooking has some negative effects on antioxidative capacity when determined using different antioxidant methods except for a significant increment in 1,1'-diphenyl-2-picrylhydrazyl radical-scavenging activity, while ACE inhibitory activity increases significantly after cooking compared with control samples. After gastrointestinal digestion of samples, there is a significant increment of the antioxidant and ACE inhibitory activities in comparison with control and cooked samples. Particularly, after gastrointestinal digestion, free thiols content and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical-cation-scavenging activity of Xuanwei ham, respectively, increase about twice and fourfold, while ACE inhibitory activity increases about twice compared to cooked samples, reaching the value of 83.73%. Therefore, through cooking the antioxidant activity and ACE inhibitory activity of Xuanwei ham are not completely lost and a part of them is still maintained, while gastrointestinal digestion produces a significant enhancement in both bioactivities, highlighting a greater potential for a beneficial physiological effect on human health after eating it.