Seasonal ultrastructural changes in apocrine gland cells in back skin of male brown bears ( Ursus arctos )
Seasonal ultrastructural changes in apocrine gland cells in back skin of male brown bears ( Ursus arctos )
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雄性棕熊(Ursus arctos)背部皮肤顶泌腺细胞的季节性超微结构变化
DOI：
10.1002/jemt.23564
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发表时间：
2020
影响因子：
2.5
通讯作者：
Matsui Motozumi
中科院分区：
文献类型：
--
作者：
Tomiyasu Jumpei;Bochimoto Hiroki;Kondoh Daisuke;Sato Yoshikazu;Matsumoto Naoya;Sasaki Kazuyoshi;Haneda Shingo;Matsui Motozumi
背部皮肤的油性分泌物参与雄性棕熊（Ursus arctos）的标记行为，背部皮肤的顶浆分泌腺在繁殖季节被激活。在这里，我们研究了雄性棕熊背部皮肤顶泌腺细胞的细胞器的季节性变化，使用透射电子显微镜（TEM）和锇浸渍扫描电子显微镜（OM‐SEM）。繁殖季节和非繁殖季节的线粒体和细胞内颗粒的形态特征以及分泌机制明显不同。TEM结果显示，在非繁殖季节，低密度颗粒的内容物通过频繁的胞吐作用释放到腺腔中，并且香肠形线粒体位于核周区域。相反，在繁殖季节，高密度颗粒出现在顶端区域和突起中，肿胀的线粒体和溶酶体样细胞器分离成高密度颗粒位于核周区域。OM‐SEM结果显示，在繁殖季节，线粒体肿胀，只有少数部分发育的嵴，小线粒体的嵴形状与顶端区域肿胀线粒体中的嵴相似。这些结果表明，小线粒体对应于TEM鉴定的高密度颗粒。这些发现表明，顶泌腺细胞中的线粒体肿胀、退化、破裂成小块，并最终在繁殖季节被顶泌分泌物释放。以这种分泌方式释放的小线粒体可能是棕熊在繁殖季节油性分泌物中化学信号的来源。
Oily secretions from the back skin are involved in the marking behavior of male brown bears (Ursus arctos), and apocrine glands in back skin are activated during the breeding season. Here, we investigated seasonal changes in the intracellular organelles of apocrine gland cells in the back skin of male brown bears using transmission electron microscopy (TEM) and osmium‐maceration scanning electron microscopy (OM‐SEM). The morphological features of mitochondria and intracellular granules, and secretory mechanisms obviously differed between breeding and non‐breeding seasons. The TEM findings showed that contents of low‐density granules were released into the glandular lumen by frequent exocytosis, and sausage‐shaped mitochondria were located in the perinuclear region during the non‐breeding season. In contrast, high‐density granules appeared in the apical region and in projections during the breeding season, and swollen mitochondria and lysosome‐like organelles separating into high‐density granules were located in the perinuclear region. The OM‐SEM findings revealed swollen mitochondria with only a few partially developed cristae, and small mitochondria with cristae shaped like those in swollen mitochondria in the apical regions during the breeding season. These findings indicated that the small mitochondria corresponded to the high‐density granules identified by TEM. These findings suggested that mitochondria in apocrine gland cells swell, degenerate, fracture into small pieces, and are finally released by apocrine secretions during the breeding season. Small mitochondria released in this secretory manner might function as the source of chemical signals in the oily secretions of brown bears during the breeding season.