Fazel A R, Thompson R P, Sumida H, Schulte B A
Department of Anatomy and Cell Biology, Medical University of South Carolina, Charleston 29425.
Am J Anat. 1989 Jan;184(1):85-94. doi: 10.1002/aja.1001840110.
Rat embryos at days 10-18 of gestation and chicken embryos at days 3-6 of incubation were fixed and processed for lectin histochemistry. The distribution of binding sites for a lectin from the peanut Arachis hypogaea (PNA) conjugated to horseradish peroxidase (HRP) was determined on tissue sections both before and after enzymatic cleavage of sialic acid with neuraminidase (sialidase). Endocardial cushion tissue in the rat, but not in the chick, reacted with PNA-HRP prior to digestion with sialidase. Endocardium of both species (12 and 13 days in rat, 5 and 6 days in chick), particularly at the level of endocardial cushions, reacted strongly with the sialidase-PNA sequence; this staining decreased markedly after day 14 of gestation in the rat. PNA binding sites capped by sialic acid were most abundant in the developing rat heart during the critical period of endocardial cushion formation and decreased as development proceeded. The marked changes in the appearance and distribution of cardiac cell and tissue glycoconjugates during cardiogenesis support the concept that rapid changes occur in the structure of complex carbohydrates during embryonic and fetal development. The findings also suggest that such glycosylation-related events may be species specific.
对妊娠第10 - 18天的大鼠胚胎和孵化第3 - 6天的鸡胚胎进行固定，并进行凝集素组织化学处理。用神经氨酸酶（唾液酸酶）对唾液酸进行酶解前后，在组织切片上测定了与辣根过氧化物酶（HRP）偶联的花生凝集素（PNA）的结合位点分布。大鼠的心内膜垫组织在用唾液酸酶消化前与PNA - HRP发生反应，而鸡的心内膜垫组织则不发生反应。两种动物（大鼠12和13天，鸡5和6天）的心内膜，特别是在心内膜垫水平，与唾液酸酶 - PNA序列强烈反应；在大鼠妊娠第14天后，这种染色明显减少。在大鼠心内膜垫形成的关键时期，被唾液酸封闭的PNA结合位点在发育中的大鼠心脏中最为丰富，并随着发育进程而减少。心脏发生过程中心脏细胞和组织糖缀合物的外观和分布的显著变化支持了这样一种概念，即在胚胎和胎儿发育过程中，复杂碳水化合物的结构会发生快速变化。这些发现还表明，这种与糖基化相关的事件可能具有物种特异性。
