Cinelli Leonardo P, Castro Michelle O, Santos Livia L, Garcia Clarice R, Vilela-Silva Ana-Cristina E S, Mourão Paulo A S
Laboratório de Tecido Conjuntivo, Hospital Universitário Clementino Fraga Filho, Rio de Janeiro, RJ 21941-590, Brazil.
Glycobiology. 2007 Aug;17(8):877-85. doi: 10.1093/glycob/cwm058. Epub 2007 Jun 5.
The egg jellies of sea urchins contain sulfated polysaccharides with unusual structures, composed of linear chains of l-fucose or l-galactose with well-defined repetitive units. The specific pattern of sulfation and the position of the glycosidic bond vary among sulfated polysaccharides from different species. These polysaccharides show species specificity in inducing the acrosome reaction, which is a critical event for fertilization. Females of the sea urchin Lytechinus variegatus spawn eggs containing a sulfated fucan with the repetitive sequence 3-alpha-L-Fucp-2(OSO(3))-1 --> 3-alpha-L-Fucp-4(OSO(3))-1 --> 3-alpha-L-Fucp-2,4(OSO(3))-1 --> 3-alpha-L-Fucp-2(OSO(3))-1. We now observe that, close to winter, a period of decreased fertility for the sea urchin, the females synthesize a distinct sulfated fucan with a simple structure, composed of 4-sulfated, 3-linked alpha-fucose residues. This sulfated fucan is inactive when tested in vitro for the acrosome reaction using homologous sperm. The amount of egg jellies spawned by females (and their constituent sulfated polysaccharides) varied greatly throughout the year. Apparently, there is a correlation between the temperature of the sea water and the expression of the 4-sulfated, 3-linked sulfated fucan. Overall, we described the occurrence of two isotypes of sulfated fucan in the egg jelly of the sea urchin L. variegatus, which differ in their biological activity and may be involved in the periodicity of the reproductive cycle of the invertebrate.
海胆的卵胶含有结构独特的硫酸化多糖，由具有明确重复单元的L-岩藻糖或L-半乳糖线性链组成。不同物种的硫酸化多糖在硫酸化的具体模式和糖苷键的位置上存在差异。这些多糖在诱导顶体反应方面表现出物种特异性，而顶体反应是受精的关键事件。多棘刺海胆（Lytechinus variegatus）的雌性产卵时，卵中含有一种具有重复序列3-α-L-岩藻糖基-2(OSO(3))-1→3-α-L-岩藻糖基-4(OSO(3))-1→3-α-L-岩藻糖基-2,4(OSO(3))-1→3-α-L-岩藻糖基-2(OSO(3))-1的硫酸化岩藻聚糖。我们现在观察到，接近冬季时，这是海胆繁殖力下降的时期，雌性会合成一种结构简单的独特硫酸化岩藻聚糖，由4-硫酸化、3-连接的α-岩藻糖残基组成。在体外使用同源精子进行顶体反应测试时，这种硫酸化岩藻聚糖没有活性。雌性产卵的卵胶量（及其所含的硫酸化多糖）在一年中变化很大。显然，海水温度与4-硫酸化、3-连接的硫酸化岩藻聚糖的表达之间存在相关性。总体而言，我们描述了多棘刺海胆卵胶中两种硫酸化岩藻聚糖同种型的出现，它们的生物活性不同，可能与这种无脊椎动物生殖周期的周期性有关。
