Readio J, Chen M H, Meola R
Entomology Department, Texas A&M University 77843-2475, USA.
J Med Entomol. 1999 May;36(3):355-60. doi: 10.1093/jmedent/36.3.355.
The synthesis of juvenile hormone in vitro by diapausing and nondiapausing Culex pipiens L. was measured by radiochemical assay. Paired corpora allata from diapausing females synthesized < 18 fmols of juvenile hormone per hour during the first 3 wk after emergence. In contrast, juvenile hormone synthesis in nondiapausing females increased rapidly reaching a peak of 87.3 +/- 21 (mean +/- SE) fmol/h 3 d after emergence. By 3 wk, juvenile hormone synthesis had decreased in both groups of females, but corpora allata from nondiapausing mosquitoes still were 3 times more active than those from diapausing mosquitoes. By 16 wk after diapause induction, females maintained at 8:16 (L:D) h and 15 degrees C produced levels of juvenile hormone similar to 3-wk-old nondiapausing females. When females were held in diapause conditions for up to 22 wk, follicles gradually grew longer and by 15 wk were significantly longer than in the previous 14 wk. Blood feeding also increased in older females, indicating that over time, juvenile hormone synthesis gradually stimulated blood-feeding behavior. When 21-d-old diapausing mosquitoes were moved to a long-day photoperiod of 16:8 (L:D) h and 26 degrees C, juvenile hormone synthesis increased rapidly and peaked 5 d later while the ovarian follicles grew to the resting stage. Allatectomy of young diapausing females prevented follicle growth and blood feeding when diapause was terminated prematurely, demonstrating that the physiological events associated with diapause termination were associated with juvenile hormone biosynthesis.
通过放射化学分析法测定了滞育和非滞育致倦库蚊体外保幼激素的合成。滞育雌蚊羽化后的前3周，配对的咽侧体每小时合成的保幼激素少于18飞摩尔。相比之下，非滞育雌蚊的保幼激素合成迅速增加，羽化后3天达到峰值87.3±21（平均值±标准误）飞摩尔/小时。到3周时，两组雌蚊的保幼激素合成均下降，但非滞育库蚊的咽侧体活性仍比滞育库蚊的高3倍。滞育诱导后16周，饲养在8:16（光照:黑暗）小时和15摄氏度条件下的雌蚊产生的保幼激素水平与3周龄非滞育雌蚊相似。当雌蚊在滞育条件下饲养长达22周时，卵泡逐渐变长，到15周时明显长于前14周。老龄雌蚊的吸血行为也增加，表明随着时间推移，保幼激素合成逐渐刺激吸血行为。当21日龄滞育库蚊转移到16:8（光照:黑暗）小时和26摄氏度的长日照光周期时，保幼激素合成迅速增加，并在第5天达到峰值，同时卵巢卵泡发育到静止期。对年轻滞育雌蚊进行咽侧体切除，在滞育过早终止时可阻止卵泡生长和吸血，这表明与滞育终止相关的生理事件与保幼激素生物合成有关。
