Conjugation in the marine oligotrich ciliates ( Ciliophora, Oligotrichida) --its systematic taxonomy and occurrence

• Main Authors: Lee, Meng-Lun, 李孟倫
• Other Authors: Chiang, Kuo-Ping
• Format: Others
• Language: zh-TW
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/wb72jx

碩士 === 國立臺灣海洋大學 === 海洋環境化學與生態研究所 === 103 === We studied the conjugation process of oligotrich ciliates in the genus Strombidium (Order Oligotrichida,) by observing their morphology, infraciliature and nuclei, and discussed the systematics of the class Oligotrichea. The morphology of oligotrich ciliates is similar to that of Halteria sp. (Order Halteriida), hence they are grouped into the same suborder by morphologists, but however, oligotrich and choreotrich ciliates (Order Choreotrichida) are closely related according to the genetic analysis. In the present study, both oligotrich and choreotrich exhibit much similar conjugation processes, including the similar morphological and nuclear characters, indicating that both Oligotrichida and Choreotrichida ciliatesare closely plesiomorphic, therefore substantiate the results of genetic analysis. The conjugation in oligotrich ciliates occurs when the ratio of prey to predator abundances is reduced to 1x106 in laboratory cultures. In our experiment, despite the stable abundance of the bacteria during the culture period was decreased evidently after 16-18 days of non-conjugation behavior in ciliates, indicating that the ciliate community was getting old and died without conjugation. Keeping starvation can induced conjugation in Tetrahymena rhermophile, but not in Strombidium as observed in the present study. We presumed henceforth that the conjugation behavior of oligotrich ciliates is induced by the decrease of the prey/predator ratio. Keywords: Strombidiida ciliate, conjugation, taxonomy, conjugation occurrence