虱目魚視覺與脂眼瞼組成和功能的初步研究

A Preliminary Study on the Vision of Milkfish (Chanos chanos) and the Components and Functions of its Adipose Eyelid

張家豪(Chia-Hao Chang)

指導教授 ： 焦傳金 ； 嚴宏洋

國立清華大學/生命科學院/分子醫學研究所/碩士(2007年)

https://doi.org/10.6843/NTHU.2007.00489

摘要

虱目魚為廣鹽性魚類並廣泛分布於印度洋及太平洋亞熱帶、熱帶水域。一個完全遮蓋住眼球前方並於眼球間形成一個充滿液體腔室的脂眼瞼，是虱目魚重要的型態特徵之一。本研究的目的在於瞭解脂眼瞼的生物功能。經由多種組織化學染色方法與掃描式電子顯微鏡的研究發現，脂眼瞼是由三層組織所構成：最外層為多細胞層的表皮組織，最內層為單層的上皮組織，而中間層則為結締組織。此一結締組織則是由第一型膠原原纖維所組成。
使用滲透壓儀測量腔室中液體發現，此液體的滲透壓值不論虱目魚是適應在何種環境鹽度下，都會高於環境滲透壓值。而在不同的環境鹽度下，此液體滲透壓值的變動也大於血清滲透壓值的變動。組織免疫染色和西方墨點法至少發現了一種參與滲透壓調節的離子運輸蛋白：Na＋/K＋ ATPase (NKA), 它可表現在脂眼瞼最外層的表皮組織細胞上。第一型膠原原纖維提供脂眼瞼韌性以抵抗外來的撞擊，而擁有較高滲透壓值的腔室內液體則提供膨壓，使得此一腔室有如避震器一般吸收外界撞擊的力道。
脂眼瞼可以將波長短於300 nm 的紫外光線濾過，但卻不參與眼睛對焦的功能。由於仔魚期與稚魚期的虱目魚有不同的棲息環境和食性，利用顯微分光光譜儀研究虱目魚的視網膜細胞發現到，仔魚期的視網膜較稚魚期，多擁有一紫色光的錐狀感光細胞。

關鍵字

第一型膠原原纖維 ； 滲透壓 ； 免疫染色 ； 西方墨點法 ； 穿透率 ； 視覺

並列摘要

Milkfish (Chanos chanos) is a euryhaline fish and is widely distributed around sub-tropic Indo-Pacific waters. It has an adipose eyelid in the cephalic region which covers the whole eye. A chamber exists in between eye and the eyelid, and the chamber is filled with liquid. The histological sections with different staining methods and SEM results showed that there were three distinctive layers in the adipose eyelid. The outer and inner layers were the epithelial tissues and the middle layer was the connective tissue. This connective was formed by type I collagen fibril.
The osmolarities of the fluid inside the chamber were always higher than those of ambient water and the variations were always higher than those of the plasma. The immunohistochemical and Western blotting results revealed one type of ion transporter proteins, Na＋/K＋ ATPase (NKA), which likely participated in osmoregulation on the outer epithelial layer of the eyelid. The type I collagen fibrils offered the adipose eyelids tensile strength to resist the impact. The higher osmolarities of chamber liquid provided the turgor pressure which made the fluid chambers to act as dampers to absorb the impacting force from ambient water molecular when in high speed cruising.
Light wavelength shorter than 300 nm was filtered out by the adipose eyelid, but the adipose eyelid didn’t participate in eye focusing. Because of the different habitat and feeding modes between the larval and juvenile milkfish, the microspectrophotometry (MSP) data showed that the juvenile milkfish had rod cells, red, blue, and green cone cells while the larval milkfish had additional violet cone cells.

並列關鍵字

type I collagen fibril ； osmoregulation ； immunostaining ； Western blotting ； transmission ； vision

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