Lacy E R
Am J Anat. 1983 Jan;166(1):19-39. doi: 10.1002/aja.1001660103.
Carbonic anhydrase (CAH) activity was biochemically measured and histochemically localized (at both the light and electron microscope levels) in isolated opercular membranes from teleost fish, Fundulus heteroclitus, adapted to freshwater (FW), seawater (SW), and double-strength seawater (2 x SW). The normal morphology of this membrane showed that its epithelial portion consisted of five cell types: (1) chloride cells, which have been previously implicated as responsible for the active chloride transport across the epithelium; (2) mucous cells; (3) pavement cells, which formed the major portion of the free epithelial surface; (4) supportive cells, which had an abundance of intermediate (10 nm)-type filaments suggesting a structural role for these cells; and (5) vesicular cells, which were characterized by various types of membrane-bound vesicles, including lysosomes, and numerous free ribosomes. Vesicular cells may be stem cells and/or endocrine cells. Hansson's histochemical method for CAH revealed cobalt sulfide reaction product confined to the following structures in fish from each environment: (1) chloride cells: throughout the cytoplasm and some nuclear staining; (2) mucous cells: throughout the cytoplasm, some nuclear staining, and some in mucous granules; (3) vesicular cells: confined to lysosomes, some of the vesicles, and nucleoli; (4) a small portion of the intracellular space between adjacent vesicular cells and supportive cells; and (5) supportive cells: in nucleoli and occasionally in larger membrane-bound lysosomelike structures. Acetazolamide (10(-5) M) and potassium cyanate (KCNO) (10(-1) M) in Hansson's incubation medium completely inhibited the formation of reaction product. Biochemical determination of CAH activity on vascularly perfused, isolated opercular membranes showed no statistically significant difference in enzyme activity between environmental groups. The following units of activity/mg opercular membrane protein were measured: FW: 0.63 +/- 0.02; SW: 0.43 +/- 0.08; 2 x SW: 0.64 +/- 0.09.
对适应淡水（FW）、海水（SW）和双倍强度海水（2×SW）的硬骨鱼——异齿底鳉分离出的鳃盖膜，进行了碳酸酐酶（CAH）活性的生化测定，并在光镜和电镜水平对其进行了组织化学定位。该膜的正常形态表明，其上皮部分由五种细胞类型组成：（1）氯细胞，此前认为其负责上皮细胞的主动氯转运；（2）黏液细胞；（3）扁平细胞，构成游离上皮表面的主要部分；（4）支持细胞，含有丰富的中间丝（10纳米），表明这些细胞具有结构作用；（5）泡状细胞，其特征是有各种膜结合泡，包括溶酶体，以及大量游离核糖体。泡状细胞可能是干细胞和/或内分泌细胞。Hansson的CAH组织化学方法显示，来自每种环境的鱼中，硫化钴反应产物局限于以下结构：（1）氯细胞：整个细胞质和一些核染色；（2）黏液细胞：整个细胞质、一些核染色以及黏液颗粒中的一些；（3）泡状细胞：局限于溶酶体、一些泡和核仁；（4）相邻泡状细胞和支持细胞之间的一小部分细胞内空间；（5）支持细胞：在核仁中，偶尔在较大的膜结合溶酶体样结构中。Hansson孵育培养基中的乙酰唑胺（10⁻⁵M）和氰酸钾（KCNO）（10⁻¹M）完全抑制了反应产物的形成。对经血管灌注的分离鳃盖膜进行CAH活性的生化测定，结果显示不同环境组之间的酶活性无统计学显著差异。测定的每毫克鳃盖膜蛋白的活性单位如下：淡水：0.63±0.02；海水：0.43±0.08；双倍强度海水：0.64±0.09。
