Department of Biology, University of Massachusetts Boston, Boston, MA, USA.
School of health Sciences, Fujita Health University, Toyoake, Japan.
Pigment Cell Melanoma Res. 2018 May;31(3):384-392. doi: 10.1111/pcmr.12672. Epub 2017 Dec 4.
Melanin from several insect samples was isolated and subjected to chemical degradation and HPLC analysis for melanin markers. Quantification of different melanin markers reveals that insect melanins are significantly different from that of the mammalian epidermal melanins. The eumelanin produced in mammals is derived from the oxidative polymerization of both 5,6-dihydroxyindole and 5,6-dihydroxyindole-2-carboxylic acids. The pheomelanin is formed by the oxidative polymerization of cysteinyldopa. Thus, dopa is the major precursor for both eumelanin and pheomelanin in mammals. But insect eumelanin appears to be mostly made from 5,6-dihydroxyindole and originates from dopamine. More importantly, our study points out the wide spread occurrence of pheomelanin in many insect species. In addition, cysteinyldopamine and not cysteinyldopa is the major precursor for insect pheomelanin. Thus, both eumelanin and pheomelanin in insects differ from higher animals using dopamine and not dopa as the major precursor.
从几种昆虫样本中分离出黑色素，并对其进行化学降解和 HPLC 分析，以检测黑色素标志物。不同黑色素标志物的定量分析表明，昆虫黑色素与哺乳动物表皮黑色素有显著差异。哺乳动物中产生的真黑色素是由 5,6-二羟吲哚和 5,6-二羟吲哚-2-羧酸的氧化聚合产生的。而褐黑素则是由半胱氨酸多巴的氧化聚合形成的。因此，多巴是哺乳动物中真黑素和褐黑素的主要前体。但昆虫真黑色素似乎主要由 5,6-二羟吲哚组成，来源于多巴胺。更重要的是，我们的研究指出褐黑素广泛存在于许多昆虫物种中。此外，半胱氨酸多巴而不是半胱氨酸多巴是昆虫褐黑素的主要前体。因此，昆虫中的真黑素和褐黑素与高等动物不同，它们使用多巴胺而不是多巴作为主要前体。
