CELL WALL CARBOHYDRATE EPITOPES IN THE GREEN ALGA OEDOGONIUM BHARUCHAE F. MINOR (OEDOGONIALES, CHLOROPHYTA) 1
CELL WALL CARBOHYDRATE EPITOPES IN THE GREEN ALGA OEDOGONIUM BHARUCHAE F. MINOR (OEDOGONIALES, CHLOROPHYTA) 1
复制标题
绿藻细胞壁碳水化合物表位 OEDOGONIUM BHARUCHAE F. MINOR（Oedogoniales，Chlorophyta）1
作者：
J. Estevez;P. Leonardi;J. Alberghina
Oedogium bharuchae N. D. Kamat f. 营养细胞和辅助细胞 (SC) 以及卵原细胞结构的细胞壁变化。使用针对几种碳水化合物表位的单克隆抗体对小贝莱斯进行了表征。营养细胞和 SC 仅发育初级细胞壁 (PCW)，而成熟的卵原细胞则分泌第二层细胞壁，即卵原细胞壁 (OCW)。根据组织化学和免疫标记结果，在 PCW 中检测到结晶纤维素形式的 (1→4)-β-葡聚糖以及不同程度的 Me 酯化同型半乳糖醛酸 (HG) 和富含羟脯氨酸的糖蛋白 (HRGP) 表位。 OCW 显示了延伸蛋白类型的阿拉伯糖苷和低水平的阿拉伯半乳聚糖蛋白 (AGP) 聚糖，但缺乏纤维素，至少是结晶形式的纤维素。令人惊讶的是，在成熟卵原细胞的细胞质中发现了三种不同抗体（LM-5、LM-6 和 CCRC-M2）的强烈共标记，表明存在鼠李糖半乳糖醛酸 I (RG-I) 样结构。我们的结果讨论了卵原细胞分化过程中这些细胞壁表位与多糖和 O-糖蛋白的可能功能。这项研究首次尝试表征 O. bharuchae 中这两种类型的细胞壁，比较它们与其他绿藻和陆地植物的相似性和差异。这项工作对理解细胞壁如何从简单的少细胞生物进化到复杂的多细胞生物做出了贡献。
Cell wall changes in vegetative and suffultory cells (SCs) and in oogonial structures from Oedogonium bharuchae N. D. Kamat f. minor Vélez were characterized using monoclonal antibodies against several carbohydrate epitopes. Vegetative cells and SCs develop only a primary cell wall (PCW), whereas mature oogonial cells secrete a second wall, the oogonium cell wall (OCW). Based on histochemical and immunolabeling results, (1→4)‐β‐glucans in the form of crystalline cellulose together with a variable degree of Me‐esterified homogalacturonans (HGs) and hydroxyproline‐rich glycoprotein (HRGP) epitopes were detected in the PCW. The OCW showed arabinosides of the extensin type and low levels of arabinogalactan‐protein (AGP) glycans but lacked cellulose, at least in its crystalline form. Surprisingly, strong colabeling in the cytoplasm of mature oogonia cells with three different antibodies (LM‐5, LM‐6, and CCRC‐M2) was found, suggesting the presence of rhamnogalacturonan I (RG‐I)–like structures. Our results are discussed relating the possible functions of these cell wall epitopes with polysaccharides and O‐glycoproteins during oogonium differentiation. This study represents the first attempt to characterize these two types of cell walls in O. bharuchae, comparing their similarities and differences with those from other green algae and land plants. This work represents a contribution to the understanding of how cell walls have evolved from simple few‐celled to complex multicelled organisms.