中文摘要：

乳酸脱氢酶（1acticdehydrogenase，LDH）是糖酵解途径的终止酶，在整个昆虫的发育阶段长期存在。本试验采用同源克隆和锚定PCR技术，从异色瓢虫Harmoniaaxyridis中克隆到HaxLDH基因的cDNA全序列（GenBank登录号HM362898），全长1336bp，包含214bp的3’非编码区域和123bp的5，非编码区域，可读框长999bp，编码332个氨基酸。通过软件分析，预测该基因编码蛋白的分子量为36．2kD，理论等电点为8．62；包含1个糖基化位点，无信号肽序列和跨膜结构。同源比对不同昆虫的LDH基因cDNA序列，发现HaxLDH拥有8个非常保守的结构域：DLQHG、TAGV／ARQK／RE／DGES／TRL、LVQRN、GSGTNLD、SCHGW／YI／VI／VGEHGD、VWSG／AVNV／IAGV、AYEV／IIK／RLKGYTS／NWAI／VGLS和LSLP。HaxLDH与赤拟谷盗Triboliumcastaneum的LDH同源性最高，达67％；系统发育分析也表明二者亲缘关系较近。本研究为探讨LDH在昆虫发育和逆境中的作用奠定了基础。

英文摘要：

Lactic dehydrogenase （LDH） of Harmonia axyridis was cloned by homological cloning and anchored PCR. The full length of HaxLDH cDNA sequence is 1336 bp （GenBank accession number HM362898）, which contains a 3＇ untranslated region of 214 bp and a 5＇ untranslated region of 123 bp. HaxLDH cDNA contains an open reading frame of 999 bp, encoding a protein of 332 amino acids residues with calculated molecular mass of 36.20 kD and pI of 8.62. It has one potential N-glycosylation site （residue 352）, with no signal peptide, putative cleavage sites and transmembrane domain. Blast analysis indicated that HaxLDH contains eight conservative domains, DLQHG, TAGV/ARQK/RE/DGES/TRL, LVQRN, GSGTNLD, SCHGW/YI/VINGEHGD, VWSG/AVNV/IAGV, AYEV/IIK/RLKGYTS/NWAI/VGLS and LSLP of LDH family. HaxLDH had 67% identity with that of Tribolium castaneum, and phylogenetic analysis shows that these two species are most closely related.