利用組織學與分子生物學比較回聲定位蝙蝠和囓齒動物的聽覺構造

Histological and molecular biological comparisons of auditory structure between echolocation bats and rodents

蕭淳任(Hsiao Chun-Jen)

指導教授 ： 吳忠信

國立臺灣師範大學/理學院/生命科學系/博士(2016年)

https://doi.org/10.6345/NTNU202204355

摘要

從演化的角度來看，每種動物的聽覺功能主要是有效處理關於通訊和聲音定向的生物相關訊息，雖然哺乳動物的聽覺系統基本架構大致上都相同，但回聲定位蝙蝠與囓齒類動物用於通訊的聲音則是相當不同，且回聲定位蝙蝠的聽覺系統必須要能夠有效地處理它們的物種特異性聲音及從障礙物或獵物反彈回來的微弱回聲，因此回聲定位蝙蝠與囓齒類動物的聽覺適應性可能有所差異。為此，本博士論文主要利用核磁共振圖像、組織化學技術，分析回聲定位蝙蝠與囓齒類動物在周邊聽覺器官(耳蝸)與中樞聽覺系統上的結構差異，並進一步利用分子生物學技術的西方墨點法，了解發聲與聽覺相關蛋白質(例如FOXP2, Otoferlin, Prestin)的表現量。本論文研究發現儘管所有這些動物物種有著相似的耳蝸結構，但是對於耳蝸的大小和螺旋數目各不相同，定頻-調頻蝙蝠(CF-FM蝙蝠)與調頻蝙蝠(FM蝙蝠)的耳蝸比囓齒類動物(大鼠和小鼠)具有較大體積的耳蝸和更多的螺旋數目，而CF-FM蝙蝠相較於FM蝙蝠與囓齒類動物，具有最大體積的耳蝸和最多的螺旋數目。探討中樞聽覺系統構造發現，CF-FM蝙蝠和FM蝙蝠的中腦(上丘和下丘)、小腦相較於囓齒類動物來得大，但在嗅球與大腦上則是剛好相反。進一步檢視腦組織的蛋白質表現量，結果發現不論是FOXP2或是Otoferlin的蛋白質表現量也是回聲定位蝙蝠比囓齒類動物高。綜觀上述實驗結果，比較CF-FM蝙蝠和FM蝙蝠的中腦(上丘和下丘)和小腦大小，以及FOXP2表現量和Otoferlin表現量，皆是以CF-FM蝙蝠為最大最高。本研究推測這些動物物種在耳蝸大小、耳蝸螺旋數目、大腦、中腦、小腦、嗅球、FOXP2表現量及Otoferlin表現量上的差異與這些動物的生物相關聲音、聲學特性及生物聲學行為有關。

關鍵字

蝙蝠 ； 囓齒動物 ； 耳蝸大小 ； 核磁共振 ； 腦的大小

並列摘要

From the evolutionary perspective, the auditory perception of each animal species is built for effective processing of the biologically relevant signals used for communication and acoustically guided orientation. Although echolocation bats and other mammals share the basic design of auditory system for sound reception, those sound pulses used by echolocation bats for orientation and by rodents for communication are quite different. Conceivably, echolocation bats must be specialized to effectively process their species-specific sounds and the echo bound from the environment and targets. This PhD thesis examined the difference between the peripheral auditory organ “cochlea” and the central nervous system of these animal species by using magnetic resonance images, histological techniques and western blotting analysis. We reported that all these animal species share similar cochlear structure, but they vary in the cochlear size, cochlear turns. The bats using constant frequency-frequency modulated pulses (CF-FM bat) and frequency-modulated pulses (FM bat) for echolocation have larger cochlear size, more cochlear turns than those of the rodents (mouse and rats). Furthermore, the cochlear size, cochlear turns and Otoferlin expression of CF-FM bat are largest. In the central nervous system, we found that CF-FM bats and FM bats have larger volume of midbrain nuclei (inferior and superior colliculi) and cerebellum relative to the size of the brain compared to those of rodents. Also, the CF-FM bats and FM bats have smaller volume of cerebrum and olfactory bulb but greater expression of Otoferlin and FOXP2 than those of rodents. In addition, CF-FM bats have larger cerebrum and greater expression of Otoferlin and FOXP2 than those of FM bats. We suggested that the difference in cochlear size, cochlear turns, brain structure size and protein expression is associated with their relevant sounds, acoustic behavior and foraging behavior of these animal species.

並列關鍵字

rodents ； Otoferlin

參考文獻

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