Study on Gill Mitochondria-rich (MR) Cell of Tilapia (Oreeochromis mossambicus) : Morphology and Expression of Transporter

• Main Authors: Ching Pei Chen, 陳金貝
• Other Authors: Pung Pung Hwang
• Format: Others
• Language: zh-TW
• Published: 1999
• Online Access: http://ndltd.ncl.edu.tw/handle/38302012689313176138

碩士 === 國立臺灣大學 === 漁業科學研究所 === 87 === In gill epithelium, mitochondria-rich cells (MR cells) are considered to be the major cell type for ion- and osmo- regulation. In fresh water, gill MR cells are suggested to be responsible for ion uptake. Based on SEM (scanning electron microscope) observations on the apical surface, MR cells are classified into three types, wavy-convex, shallow-basin, and deep-hole types. Fish were acclimated to three hypotonic medium, F-Cl (chloride-free)、H-Na (high Na2SO4) and H-NaCl (high NaCl), and the relative densities of the three types of MR cells were examined. The major cell type in chloride-free medium (F-Cl and H-Na) was wavy-convex, while that in H-NaCl was deep-hole. The major function of wavy-convex MR cells was suggested to be associated with uptake of Cl- but not Na+. Moreover, numerous multicellular complexes of MR cells developed in the chloride-free medium, suggesting to increase the apical surface area of MR cells for the enhancement of Cl- uptake. According to the results of double-labeling of Con A and Na+,K+-ATPase, the patterns of the relative abundance of MR cells labelled with Con A were similar to those examined by SEM, indicating that Con A is another suitable indicator to distinguish different types of MR cells. Western boltting analysis indicated that the amount of gill Na+,K+-ATPase was higher in the tilapia acclimated to F-Cl and H-Na than those acclimated to H-NaCl, suggesting that gill MR cells expressed various levels of Na+,K+-ATPase to perform the transport functions for different ions.