Andersson Marie, Karlsson Oskar, Brandt Ingvar
Department of Environmental Toxicology, Uppsala University, SE-752 36 Uppsala, Sweden.
Department of Pharmaceutical Biosciences, Uppsala University, SE-751 24 Uppsala, Sweden; Department of Clinical Neuroscience, Karolinska Institutet, Center for Molecular Medicine, SE-17176 Stockholm, Sweden.
Ecotoxicol Environ Saf. 2018 Jan;147:720-724. doi: 10.1016/j.ecoenv.2017.09.032. Epub 2017 Sep 20.
The neurotoxic amino acid β-N-methylamino-L-alanine (BMAA) has been implicated in the etiology of neurodegenerative disorders. BMAA is also a known developmental neurotoxin and research indicates that the sources of human and wildlife exposure may be more diverse than previously anticipated. The aim of the present study was therefore to examine whether BMAA can be transferred into birds' eggs. Egg laying quail were dosed with C-labeled BMAA. The distribution of radioactivity in the birds and their laid eggs was then examined at different time points by autoradiography and phosphoimaging analysis. To evaluate the metabolic stability of the BMAA molecule, the distribution of C-methyl- and C-carboxyl-labeled BMAA were compared. The results revealed a pronounced incorporation of radioactivity in the eggs, predominantly in the yolk but also in the albumen. Imaging analysis showed that the concentrations of radioactivity in the liver decreased about seven times between the 24h and the 72h time points, while the concentrations in egg yolk remained largely unchanged. At 72h the egg yolk contained about five times the concentration of radioactivity in the liver. Both BMAA preparations gave rise to similar distribution pattern in the bird tissues and in the eggs, indicating metabolic stability of the labeled groups. The demonstrated deposition into eggs warrants studies of BMAAs effects on bird development. Moreover, birds' eggs may be a source of human BMAA exposure, provided that the laying birds are exposed to BMAA via their diet.
神经毒性氨基酸β-N-甲基氨基-L-丙氨酸（BMAA）被认为与神经退行性疾病的病因有关。BMAA也是一种已知的发育神经毒素，研究表明，人类和野生动物接触BMAA的来源可能比之前预期的更多样化。因此，本研究的目的是检验BMAA是否能转移到鸟类的蛋中。给产蛋鹌鹑投喂碳标记的BMAA。然后通过放射自显影和磷成像分析在不同时间点检测鸟类及其所产蛋中放射性的分布。为了评估BMAA分子的代谢稳定性，比较了碳甲基标记和碳羧基标记的BMAA的分布情况。结果显示蛋中放射性明显掺入，主要在蛋黄中，但也存在于蛋清中。成像分析表明，肝脏中放射性浓度在24小时至72小时时间点之间下降了约7倍，而蛋黄中的浓度基本保持不变。在72小时时，蛋黄中的放射性浓度约为肝脏中的5倍。两种BMAA制剂在鸟类组织和蛋中产生了相似的分布模式，表明标记基团的代谢稳定性。BMAA在蛋中的沉积表明有必要研究其对鸟类发育的影响。此外，如果产蛋鸟类通过饮食接触BMAA，那么鸟蛋可能是人类接触BMAA的一个来源。
