Carroll Edward J
Department of Biology, University of California, Riverside, California 92521, USA.
Dev Growth Differ. 1996 Feb;38(1):9-14. doi: 10.1046/j.1440-169X.1996.00002.x.
Development of the Paraguayan anuran Lepidobatrachus laevis is unusual in that the larvae are obligate carnivores, facultative cannibals and apparently exist at high environmental temperatures in their natural habitat. In the present study, the effect of environmental temperature on the rate of anuran development was investigated. The larvae have a thermotolerance range of 18°C for normal development between 19 and 37°C. The effect of temperature on the rate of development was dramatic; larvae that were incubated at 36.8°C develop to stage 24 (Gosner) in approximately 9 h compared with 24 h for larvae incubated at 19°C. The ability of larvae to survive heat shock was also examined; larvae did not survive a shock of 45°C for 15 min when it was administered at stages 3, 5, 9, 10 or 20. However, using the same heat shock conditions, 50% survival was observed when larvae were shocked at stage 16. To study protein synthesis during heat shock, larvae were pulsed with [ S]-methionine during heat shock and labeled proteins were analyzed by electrophoresis under reducing and denaturing conditions. Larvae synthesized two sets of heat-shock proteins at doublet molecular weights of 83/78 and 62/59 kDa. These proteins were synthesized independently of the stage of development at which the shock was administered or the magnitude of the heat shock.
巴拉圭无尾两栖动物光滑爪蟾的发育不同寻常，因为其幼体是专性肉食动物、兼性同类相食者，且在自然栖息地中显然处于较高的环境温度下。在本研究中，调查了环境温度对无尾两栖动物发育速率的影响。幼体正常发育的耐热范围为18°C，发育温度在19至37°C之间。温度对发育速率的影响非常显著；在36.8°C下孵化的幼体大约9小时发育到24期（戈斯纳分期），而在19°C下孵化的幼体则需要24小时。还检查了幼体在热休克中的存活能力；当在第3、5、9、10或20期给予45°C持续15分钟的热休克时，幼体无法存活。然而，在相同的热休克条件下，当幼体在第16期受到热休克时，观察到50%的存活率。为了研究热休克期间的蛋白质合成，在热休克期间用[ S] - 甲硫氨酸对幼体进行脉冲标记，并在还原和变性条件下通过电泳分析标记的蛋白质。幼体合成了两组热休克蛋白，其双分子质量分别为83/78 kDa和62/59 kDa。这些蛋白质的合成与给予热休克时的发育阶段或热休克的强度无关。
