Laboratory of Bioorganic Chemistry, NIDDK, NIH, DHHS, Bethesda, Maryland 20892, USA.
J Nat Prod. 2010 Mar 26;73(3):322-30. doi: 10.1021/np900721r.
Four five-skin alkaloid extracts of the Madagascan poison frog Mantella baroni from three disturbed collection sites were compared with four five-skin extracts from three undisturbed sites. The number of alkaloids (diversity) was significantly different in M. baroni between undisturbed and disturbed collection sites, with more alkaloids generally being found in frogs from disturbed sites. Two undisturbed sites did not differ from two disturbed sites, but the third disturbed site (coded 6) had more than twice the alkaloid diversity found in frogs from the third undisturbed site (coded 5a/5b). There was no difference in the quantity of alkaloids in M. baroni between undisturbed and disturbed collection sites. The hypothesis that an undisturbed habitat confers a benefit to poison frogs dwelling therein, in allowing for the sequestration of greater alkaloid diversity and amounts, is challenged by our results. In the course of our study, we found that collections of frogs separated by an interval of three months at an undisturbed site differed by only 4% in alkaloid composition over this period, whereas frogs collected at a disturbed site and collected approximately three months later already had a 26% difference in alkaloid composition between the two collections. This constancy of skin alkaloid composition likely reflects a constancy of dietary prey items consumed by frogs at undisturbed sites.
来自三个受干扰采集点的马达加斯加毒蛙 Mantella baroni 的四个五皮肤生物碱提取物与来自三个未受干扰采集点的四个五皮肤提取物进行了比较。受干扰和未受干扰采集点的 M. baroni 之间的生物碱数量（多样性）存在显著差异，通常在受干扰采集点的青蛙中发现更多的生物碱。两个未受干扰的地点与两个受干扰的地点没有区别，但第三个受干扰的地点（编码为 6）的生物碱多样性是第三个未受干扰地点（编码为 5a/5b）的青蛙的两倍多。受干扰和未受干扰采集点的 M. baroni 中的生物碱数量没有差异。未受干扰的栖息地为栖息其中的毒蛙提供了更大的生物碱多样性和数量的隔离优势的假设，我们的结果对此提出了挑战。在我们的研究过程中，我们发现，在一个未受干扰的地点，相隔三个月采集的青蛙在这段时间内的生物碱组成仅相差 4%，而在受干扰的地点采集并在大约三个月后采集的青蛙，两个采集点之间的生物碱组成已经有了 26%的差异。皮肤生物碱组成的这种稳定性可能反映了未受干扰地点的青蛙所食用的饮食猎物的稳定性。
