Cut lactose and xgal Inducer IPTG lactose Restriction

Cut lactose and x-gal

Inducer: IPTG, lactose

Restriction enzyme

Restriction fragment length polymorphism

Nonautonomous retrotransposons encode no protein • Alu elements contain the sequence AGCT that is recognized by the restriction enzyme Alu. I. They are present in up to a million copies in the human genome. • They can not transpose by themselves. Instead they take advantage of the retrotransposition machinery of other elements, such as LINEs.

Cut lactose and x-gal

Reporter gene

Fusion protein

Fusion protein The green fluorescent protein (GFP) is composed of 238 amino acids (26. 9 k. Da), originally isolated from the jellyfish Aequorea victoria that fluoresces green when exposed to blue light.

Figure 25. 05

GFP derivatives In 2008, Osamu Shimomura, Marty Chalfie and Roger Tsien (錢永建) won the Nobel Prize in chemistry.

重組蛋白質 在寄主(host)細胞中的表達 基因 優點 • 產量大 • 操作易 質體 染色體 4, 000 kb E. coli 缺點 • no post-translation modification • inclusion body • not secrete protein

重組蛋白質 在寄主細胞中的表達 E. coli 缺點 not secrete protein gram-positive bacteria B. subtilis proteases limited vector & promoter “signal” has not found yet

DNA library Figure 22. 23

常見的動物細胞寄主 insect cell-baculovirus mammal-retrovirus chinese hamster ovary (CHO) cells immortal cell

Growth inhibition

使用chemostat為bioreactor其產量將遠大 於batch。可是為什麼 業界使用batch的比率 遠高於chemostat？ 1. Secondary products 2. Genetic instability 3. Operability and reliability 4. Market economics