Prelovsek Petra-Maja, Bulog Boris
Department of Biology, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia.
Pigment Cell Res. 2003 Aug;16(4):345-50. doi: 10.1034/j.1600-0749.2003.00061.x.
The ultrastructural characteristics of melanosomes and premelanosomes observed during the biogenesis of melanosomes in liver pigment cells of the neotenic cave salamander Proteus anguinus (Proteidae) are described. It is well known that amphibian liver pigment cells, also known as Kupffer cells (KC), contain melanosomes and are able to synthesize melanin. Liver pigment cells of P. anguinus contain numerous siderosomes and melanosomes. The melanosomes are grouped together within single-membrane-bounded bodies, named as 'clusters of melanosomes' or 'melanosomogenesis centers'. Inside such clusters, different structures are present: (1) filament-like structures, characteristic of the initial stage of melanosome biogenesis, (2) medium electron-dense melanosomes in different stages of melanization, (3) melanosomes with an electron-dense cortical area and a less electron-dense medullar area, and (4) uniformly highly electron-dense mature melanosomes or melanin granules. Histochemical and cytochemical dihydroxyphenylalanine (DOPA) oxidase reactions in pigment cells were positive. Our results confirm the ability of amphibian KC to synthesize melanin and contribute to this little known subject.
描述了在幼态洞穴蝾螈（洞螈科）肝脏色素细胞黑素小体生物发生过程中观察到的黑素小体和前黑素小体的超微结构特征。众所周知，两栖动物肝脏色素细胞，也称为库普弗细胞（KC），含有黑素小体并能够合成黑色素。洞螈的肝脏色素细胞含有大量含铁小体和黑素小体。黑素小体聚集在单膜包被的小体内，称为“黑素小体簇”或“黑素小体发生中心”。在这样的簇内，存在不同的结构：（1）丝状结构，是黑素小体生物发生初始阶段的特征；（2）处于不同黑素化阶段的中等电子密度黑素小体；（3）具有电子致密皮质区和电子密度较低髓质区的黑素小体；（4）均匀高度电子致密的成熟黑素小体或黑色素颗粒。色素细胞中的组织化学和细胞化学二羟基苯丙氨酸（DOPA）氧化酶反应呈阳性。我们的结果证实了两栖动物KC合成黑色素的能力，并为这个鲜为人知的课题做出了贡献。
