Díaz A O, García A M, Devincenti C V, Goldemberg A L
Departamento de Biología, Facultad de Ciencias Exactas y Naturales. Universidad Nacional de Mar del Plata, Funes 3250, 3er. Piso. (7600) Mar del Plata, Argentina.
Anat Histol Embryol. 2003 Dec;32(6):341-6. doi: 10.1111/j.1439-0264.2003.00490.x.
The histomorphological aspects as well as the histochemical content and distribution of glycoproteins (GPs) in the mucosa of the digestive tract of the anchovy Engraulis anchoita were studied. The buccopharyngeal cavity is lined by a squamous stratified epithelium with mucous superficial cells; the oesophagus shows two zones, cranial with a squamous stratified epithelium with mucous superficial cells and caudal with a columnar secretory epithelium. Finally, the stomach presents both the cranial and pyloric portion lined with a simple columnar epithelium. Tubular branched glands, formed by a single type of glandular cell, located along the stomach, are more numerous in the cranial portion. The GPs were identified with (1) oxidizable vicinal diols; (2) sialic acids and some of their chain variants, C7 or C9; (3) sialic acid residues with O-acyl substitution at C7 or C8; (4) carboxyl groups and (5) sulphate groups. Histochemical tests showed that the buccopharyngeal cavity presented the largest amount of the different types of mucosubstances. Epithelial secretory cells were found in the oesophagus, which synthesized a large quantity of sialosulphoglycoproteins likely to be related to a protective role. The surface epithelium of the stomach synthesizes and secretes acid and neutral GPs, probably related to the movement of fluids and to the absorption of easily digested substrates, respectively. Although great differences exist between different species, in E. anchoita as in other fish species, the wall of the digestive tract is composed of the four layers classically described for vertebrates. The GPs secreted by the epithelial cells are suggested to be important for the protection and inhibition of microorganisms. In addition, they are involved in enzymatic digestion of food, absorptive functions and lubrication of the alimentary tract.
对秘鲁鳀鱼消化道黏膜的组织形态学特征以及糖蛋白(GPs)的组织化学含量和分布进行了研究。口咽腔由具有黏液表层细胞的复层鳞状上皮覆盖;食管分为两个区域,头部区域为具有黏液表层细胞的复层鳞状上皮,尾部区域为柱状分泌上皮。最后,胃的贲门部和幽门部均由单层柱状上皮覆盖。胃内沿胃分布的、由单一类型腺细胞形成的管状分支腺,在贲门部更为丰富。通过以下方法鉴定糖蛋白:(1)可氧化的邻二醇;(2)唾液酸及其一些链变体,C7或C9;(3)在C7或C8位具有O-酰基取代的唾液酸残基;(4)羧基和(5)硫酸基团。组织化学测试表明,口咽腔中不同类型的黏液物质含量最高。在食管中发现了上皮分泌细胞,这些细胞合成了大量可能具有保护作用的唾液酸硫酸糖蛋白。胃的表面上皮合成并分泌酸性和中性糖蛋白,可能分别与液体的移动和易消化底物的吸收有关。尽管不同物种之间存在很大差异,但在秘鲁鳀鱼以及其他鱼类中,消化道壁由脊椎动物经典描述的四层组成。上皮细胞分泌的糖蛋白被认为对保护和抑制微生物很重要。此外,它们还参与食物的酶促消化、吸收功能以及消化道的润滑。