Correlation of the Period Length of Circadian Rhythms with the Length of Immaturity in Paramecium bursaria
Correlation of the Period Length of Circadian Rhythms with the Length of Immaturity in Paramecium bursaria
复制标题
草履虫昼夜节律周期长度与幼虫期长度的相关性
作者：
I. Miwa;Hirohito Yajima
摘要利用微机辅助数据采集装置测定了日本和中国不同地区30个绿草履虫品系的光积累昼夜节律。虽然大多数菌株在LL中显示出23-26小时的周期，但我们发现两个明显不同的周期菌株;短周期菌株（UK 1，21.8小时）和长周期菌株（T316，28.7小时）。来自短周期和长周期菌株之间的杂交的F1后代显示约24.7小时的中间期（范围22.5-25.8小时）。该性状在F1代中不呈孟德尔比例分布。利用亚硝基胍（MNNG）诱变，从Kz 1出发，筛选到一株短周期突变株（E2），其生长周期为21.8小时。E2与UK 1、T316杂交后代分别表现为短周期和正常周期表型。此外，从E2和野生型菌株（Sj 2 w）之间的杂交后代成为性成熟后约25分裂接合。这种不成熟的长度比野生型菌株的后代短得多（约50次分裂）。这种早熟性状以孟德尔比率遗传给后代。早成熟等位基因（EM 2）的纯合子在接合后约15次分裂后表现出交配能力。这些数据表明，有一个相关的昼夜节律的周期长度和接合后的不成熟的长度在草履虫bursaria。
Abstract The circadian photoaccumulation rhythm of thirty strains of Paramecium bursaria collected at different places in Japan and China were measured with a microcomputer assisted data collection apparatus. Although most strains showed a period of 23–26 hours in LL, we found two strains of conspicuously different periods; a short period strain (UK1, 21.8 hr) and a long period strain (T316, 28.7 hr). F1 progeny from a cross between the short and the long period strains showed an intermediate period of about 24.7 hours (range 22.5–25.8 hr). The character was not distributed in a Mendelian ratio among the F1 progeny. We isolated a mutant (E2) with short period (21.8 hr) from the stock strain Kz1 by treatment with nitrosoguanidine (MNNG). The progeny of crosses between E2 and UK1, and between E2 and T316 exhibited the short period and the normal period phenotype respectively. Moreover, the progeny from a cross between E2 and a wild type strain (Sj2w) became sexually mature about 25 fissions after conjugation. This length of immaturity is much shorter than that of the progeny from wild type strains (about 50 fissions). This early maturation character was inherited to progeny in a Mendelian ratio. Homozygotes for the early maturation allele (EM2) exhibited mating ability about 15 fissions after conjugation. These data suggest that there is a correlation between the period length of the circadian rhythm and the length of immaturity after conjugation in Paramecium bursaria.