海洋微藻基因工程的选择标记

Selective Marker of Marine Microalgal Genetic Engineering

6种海洋微藻新月菱形藻 (NitzschiaclosteriumEhr.)、牟勒氏角刺藻 (ChaetocerosmuelleriLemm .)、三角褐指藻(PhaeodactylumtricornutumBohl.)、绿光等鞭金藻 870 1 (IsochrysisgalbanaParke 870 1 )、亚心形扁藻 (Platymonassubcordi formis (Wille)Hazen)和小球藻 (ChlorellavulgarisBeij.)对 5种抗生素的敏感性实验表明 ,不同的海洋微藻对各种抗生素的敏感性不同 ,其中氯霉素是 6种海洋微藻普遍敏感的抗生素 ,它对 6种海洋微藻 72h的半抑制浓度在 5 6～2 89mg/L之间。可见氯霉素是 6种海洋微藻较理想的选择压力。因此CAT(氯霉素乙酰转移酶 )基因可作为阳性选择标记基因广泛应用于海洋微藻的基因工程研究。另外 ,牟勒氏角刺藻还对卡那霉素 ,氨苄青霉素敏感。三角褐指藻也对氨苄青霉素敏感。因此 ,NTPⅡ (新霉素磷酸转移酶 )基因和Ampr(氨苄青霉素抗性 )基因也可作为牟勒氏角刺藻基因工程研究的阳性选择标记基因。Ampr 基因还可作为三角褐指藻基因工程研究的阳性选择标记基因。

Six species of marine microalgae, viz., Nitzschia closterium Ehr., Chaetoceros muelleri Lemm., Phaeodactylum tricornutum Bohl., Isochrysis galbana Parke 8701, Platymonas subcordiformis (Wille) Hazen and Chlorella vulgaris Beij. exhibited different sensitivities to 5 kinds of antibiotics. Among the 5 kinds of antibiotics, chloromycetin was the common sensitive antibiotic for the 6 species of marine microalgae. Its 72 h EC 50 (50% effective concentration) was from 56-289 mg/L, which made chloromycetin the reasonable selective marker for the 6 species of marine microalgae.Thus, CAT (chloramphenicol acetyltransferase) gene could be widely used as selective marker in the study of marine microalgal genetic engineering. Moreover, Chaetoceros muelleri was sensitive to kanamycin and ampicillin, and Phaeodactylum tricornutum was sensitive to ampicillin, therefore, NTPⅡ (neomycin phosphotransferaseⅡ) gene and Amp r (Ampicillin resistant) gene could be used as selective marker for Chaetoceros muelleri , and Amp r gene for Phaeodactylum tricornutum .