Felip A, Piferrer F, Carrillo M, Zanuy S
Consejo Superior de Investigaciones Científicas (CSIC), Instituto de Acuicultura de Torre la Sal, 12595 Ribera de Cabanes, Castellón, Spain.
Heredity (Edinb). 1999 Oct;83 ( Pt 4):387-97. doi: 10.1038/sj.hdy.6886030.
To improve the efficiency of gynogenetic induction, the effects of UV light and thermal shock on gametes were investigated in the sea bass. Exposure of sperm to UV light (>/=15 000 erg mm-2) reduced the amount of motile spermatozoa, without affecting the duration of motility in the spermatozoa that remained motile. The Hertwig effect was elicited in eggs fertilized with sperm exposed to >/=35 000 erg mm-2 of UV light, indicating the inactivation of the DNA of the spermatozoa while retaining their ability to trigger development. Resulting embryos (24 chromosomes; one NOR) exhibited the haploid syndrome and died at hatch. Diploidy was restored in eggs fertilized with irradiated sperm by blocking meiosis II with a thermal shock (0 +/- 0.5 degrees C for 10 min, starting 5 min after fertilization). Resulting larvae ( approximately 35% survival at hatching) had 48 chromosomes, one or two NOR and no paternal chromosome fragments (gynogenetic diploids). In eggs fertilized with sperm not exposed to UV light, the same thermal shock induced 100% triploidy (72 chromosomes; one, two or three NOR), with 70% survival at hatching. Multifactorial ANOVA showed that, compared to external factors (sperm diluent, UV light and thermal shock), the contribution of broodstock to the viability of the early developmental stages was not significant (P > 0.05). Effects of the thermal shock were most evident after fertilization (30.7%) but disappeared (0%) at hatching, suggesting that the lower survival of triploids is a consequence of handling, not of the triploid condition per se. However, effects of UV light increased through development (42.5-69.7%), probably reflecting cumulative deficits in protein synthesis.
为提高雌核发育诱导效率，研究了紫外线和热休克对海鲈配子的影响。将精子暴露于紫外线（≥15000尔格/平方毫米）会减少活动精子的数量，但不影响仍具活力的精子的活动持续时间。在用暴露于≥35000尔格/平方毫米紫外线的精子受精的卵中引发了赫特维希效应，这表明精子DNA失活，同时保留了其触发发育的能力。产生的胚胎（24条染色体；一个核仁组织区）表现出单倍体综合征并在孵化时死亡。通过热休克（受精后5分钟开始，在0±0.5℃下处理10分钟）阻断减数分裂II，可使受辐照精子受精的卵恢复二倍体状态。产生的幼体（孵化时存活率约为35%）有48条染色体、一个或两个核仁组织区且无父本染色体片段（雌核发育二倍体）。在用未暴露于紫外线的精子受精的卵中，相同的热休克诱导100%的三倍体（72条染色体；一个、两个或三个核仁组织区），孵化时存活率为70%。多因素方差分析表明，与外部因素（精子稀释液、紫外线和热休克）相比，亲鱼对早期发育阶段活力的贡献不显著（P>0.05）。热休克的影响在受精后最为明显（30.7%），但在孵化时消失（0%），这表明三倍体较低的存活率是处理的结果，而非三倍体状态本身的结果。然而，紫外线的影响在发育过程中增加（42.5 - 69.7%），这可能反映了蛋白质合成中的累积缺陷。
