低温冷藏提高家蚕滞育卵NAD含量和胞质苹果酸脱氢酶活性

Chilling enhances the NAD levels and cytosolic malate dehydrogenase activity in diapause eggs of the silkworm,Bombyx mori

为了调查5℃低温处理是否改变家蚕Bombyxmori卵滞育NAD代谢,本研究利用HPLC和分光光度法测定了经25℃和5℃分别处理的滞育卵中NADH含量、NAD+含量、乳酸脱氢酶(LDH)活性和胞质苹果酸脱氢酶(cMDH)活性。结果表明:5℃处理的NAD(NADH+NAD+)含量和cMDH活性分别增加了106%和53%,并且显著高于25℃处理(P<0.01);但是两种处理的NADH/NAD+比值和LDH活性没有显著差异(P>0.05)。据此推测,5℃低温处理加强了家蚕滞育卵NAD+合成和再生能力。

To investigate whether chilling at 5 ℃ changes the metabolism of NAD in diapause eggs of the silkworm, Bombyx mori, the levels of NADH and NAD ＋ along with the activities of lactate dehydrogenase （LDH） and eytosolic malate dehydrogenase （cMDH） in diapause eggs incubated at 25℃ and 5℃, respectively, were determined using HPLC and spectrophotometric methods. NAD （NADH ＋ NAD ＋ ） levels and the cMDH activity in diapause eggs incubated at 5℃ increased by 106% and 53%, respectively, which were significantly higher than those in diapause eggs incubated at 25℃ （P 〈 0.01 ）. However, no significant difference in the NADH/NAD ＋ ratio and the LDH activity was observed between the incubation treatments at 25 ℃ and 5℃ （ P 〉 0.05 ）. It is so inferred that the ability for NAD ~ synthesis and regeneration in Bombyx diapause eggs is enhanced by chilling.