【摘要】 本文报道有关家蝇胸肌线粒体氧化磷酸化作用和亚显微结构的实验和观察结果。试验证明,家蝇胸肌线粒体在离体条件下对α-甘油磷酸有很高的氧化和磷酸化活力,而对三羧酸循环各底物及其他氧化底物的氧化和磷酸化速率则极为微弱。胸肌匀浆以及线粒体与上清液的重组合试验结果和单独用分离的线粒体试验结果基本相同,从而有利于说明造成上述现象的原因可能不是由于线粒体在制备过程中受到损伤,而是家蝇胸肌线粒体膜对这些底物存在着特殊的透性屏障。在以α-甘油磷酸为氧化底物时,线粒体在下述保温条件下可获得很高的氧化速率和P/O比值:线粒体浓度较稀(2毫升反应液中含1—2毫克线粒体蛋白);保温时间较短(10—20分钟之内)以及外加一定量的牛血浆清蛋白(0.2％)。DDT对线粒体的氧化和磷酸化反应均表现强烈的抑制作用,但在正常家蝇和抗性家蝇中则表现出一定的差别。在离体试验的条件下,DDT(0.1mM)对正常家蝇线粒体的氧化抑制40％,对磷酸化抑制60.9％,而抗性家蝇则分别为23.4％和42.7％;在反应系统中外加牛血浆清蛋白时,DDT对正常家蝇线粒体的氧化抑制71.1％,磷酸化抑制94.8％,而抗性家蝇则分别为59.7％和87.1％。在DDT(5％)处理整体家蝇时,正常家蝇线粒体的氧化被抑制21％,磷酸化被抑制33％,而抗性家蝇则分别为11.5更多还原

【Abstract】 The present investigation was undertaken in 1965-1966 to study the oxidative phosphorylation and the fine structure of the flight muscle mitochondria in the housefly Musca domestica vicina Macq. Comparisons were made between the normal (= susceptible) and DDT-resistant strains before and after DDT treatment in order to analyse the relationship between structure and function of the mitochondria. The results may be summarized as follows:1. The mitochondrial suspensions prepared from the flight muscles oxidized rapidly a-glycerophosphate and succinate, but slowly or did not oxidize most of the other citric acid cycle intermediates such as pyruvate, a-ketoglutarate, malate and fumarate as well as β-hydroxybutyrate and glutamate. The same results could be obtained when the muscle homogenate or the mitochondria plus supernatant were tested. This result may serve as the evidence in favour of the view that the isolated housefly mitochondria are not readily permeable to these intermediate compounds of citric acid cycle.2. In the cases where a-glycerophosphate was used as the substrate, a high rate of respiration (Qo2 = 413.3) and a high yield of oxidative phosphorylation (P/0 -2.00) may be obtained in the following incubation conditions: the dilute mitochondrial suspension (about 2 mg of protein of mitochondria in 2.0 ml reaction mixture), the short incubation time (about 10 minutes), and the addition of bovine plasma albumin.3. The rates of respiration and oxidative phosphrylation of the mitochondria were significantly inhibited by DDT in vitro and in vivo, but the degree of inhibition was different in normal and DDT-resistant houseflies. In the mitochondria from the normal strain the inhibition of respiration and that of phosphorylation caused by DDT (0.1 mM) in vitro were 40% and 60.9% respectively, whereas in the DDT-resistant strain the corresponding values were 23.4% and 42.7%. AVhen bovine plasma albumin was added into the incubation medium, the inhibition of respiration and that of phosphorylation of the normal housefly mitochondria were 71.1% and 94.8%, whereas in the DDT-resistant houseflies the values were 59.7% and 87.1% respectively. When the houseflies were treated with DDT (0.5%) suspension in vivo, the inhibitions of respiration and phosphorylation in the normal housefly mitochondria were 21% and 33%, whereas in DDT-resistant houseflies the values were 11.5% and 26.9% respectively. After the addition of bovine plasma albumin into the reaction medium the inhibitions of respiration and phosphorylation in the normal housefly mitochondria were 7.0% and 6.1% respectively, whereas in DDT-resistant houseflies no inhibition was observed. These results indicated that the DDT-resistant houseflies in some degree exhibited at the level of mitochondrial function more resistance to the action of DDT than the normal strain.4. An electron microscopic examination on the fine structure of the flight muscle mitochondria from the two strains of the housefly also confirmed that at the level of the cellular organelles the DDT-resistant houseflies were more resistant to the action of DDT. After the insects were treated with DDT in vivo, the mitochondra from the normal strain showed marked lysis, but in the DDT-resistant strain only some mitochondria were slightly damaged. The result demonstrated clearly that in the housefly the changes in structure and function of the mitochondria were correlative during the development of insecticide resistance.更多还原