生物技術分析 note 01

☄Chapter 16: Food Biotechnology
食品生物科技

☈第一代農業生物科技
主要目的是增加農產品產量與降低生產成本。

☈The most dominant products are the Bt products (crops with
resistance to lepidopteran pests) and herbicide-resistant
products (crops with resistance to major herbicides like those
which are glyphosate based). The crops that have been
modified in this fashion are generally field crops (e.g., corn,
potato, soybean, cotton).大部分產品是蘇立菌蛋白的產物（抗鱗
翅類蟲害）與抗除草劑，主要是一般田間作物。

☈第二代著重於消費者需要
（增加風味、增加營養價值、延長保存期限）

☄ ENGINEERING ICE PROTECTION.
THE CASE OF “ICE MINUS”
冰晶工程保護作物：冰核基因減除的案例

☈It has been known that water may remain supercooled
without forming ice crystals.
水保持在過冷的狀態就不會有冰晶形成。

☄ENGINEERING FRUIT
RIPENING
水果成熟基因工程

☈Certain fruits exhibit elevated respiration during ripening
with concomitant evolution of high levels of ethylene. 水
果成熟會生成高濃度乙烯提升風味。

☇climacteric fruits

Chlorophyll, starch, and the cell wall are degraded.
There is an accumulation of lycopene (red pigment in
tomato), sugars, and various organic acids. 其中葉綠
素、澱粉及細胞壁會分解，並累積許多茄紅素、糖及有機
酸。

☈The biosynthesis of ethylene is a two-step process in
which s-adenosyl methionine is metabolized into
aminocyclopropaneI carboxylic acid, which in turn is
converted to ethylene. By knowing the pathway of
ethylene biosynthesis, scientists may manipulate the
ripening process by either reducing the synthesis of
ethylene or reducing the effects of ethylene (i.e., plant
response).乙烯生合成有兩個步驟，s-腺甲硫胺酸代謝
生成環胺丙烷羧酸再轉化成乙烯。可以利用減少乙烯合
成或作用來控制成熟過程。

☄Reducing ethylenebiosynthesis
減少乙烯合成過程

☈SAM hydrolase

美國奧勒
岡Agritope公司，自細菌病毒選殖水解s-腺甲硫胺酸（SAM）基
因，稱為SAM水解酶基因。

☄THE FLAVR SAVR TOMATO
莎弗基因改造蕃茄

☈In this regard, the target for genetic engineering is the enzyme
polygalacturonase (PG). This enzyme accumulates as the fruit
softens, along with cellulases that break cell-wall cellulose, and pectin
methylesterase that together with PG break the pectic crosslinking
molecules in the cell wall. 基因工程主要作用對象是具半乳糖醛酸酶，
此酵素會使水果軟化，同時纖維素酶會分解細胞壁纖維素，果膠甲基脂
酶會與PG一起分解細胞壁中果膠分子。

☈The Bacillus thuringiensis (Bt) endotoxin is a
crystalline protein. It was first identified in 1911
when it was observed to kill the larvae of flour moths.
蘇力菌內毒素是一種結晶狀蛋白質，第一次發現在
1911年，能殺死麵粉幼蛾蟲。

☈It was registered as a biopesticide in the United
States in 1961. Bt is very selective in action; that is,
one strain of the bacterium kills only certain insects.
於1961年在美國註冊成為生物殺蟲劑，，對昆蟲有高
度選擇性，，一種品系只會殺死某些昆蟲。

★


B. thuringiensis var. kurstaki (for controlling lepidopteran pests of
forests and agriculture)用以防治森林和農業類鱗翅類昆蟲

var. brliner (wax moth)用以防治臘蛾

var. israelensis (dipteran vectors of human disease).用以防治引
起人類疾病的雙翅目

☈To become toxic, these endotoxins, which are predominantly
protoxins, need to be proteolytically activated in the midgut of the
susceptible insect to become toxic to the insect. These
endotoxins act by collapsing the cells of the lining of the gut
regions.內毒素引起昆蟲中毒前稱為前毒素，這些內毒素需要在敏
感昆蟲的中腸內受到蛋白質酶分解後才對昆蟲造成毒性，這些毒
素可以分解腸內細胞。

☇蟲歐洲玉米螟已經發生Bt抗性

☃with cryB1 gene product being toxic to both dipteran (Aedes
aegypti) and lepidoteran (Manduca sexta) larvae, cryB1基因產生
的毒素對雙翅類昆蟲與鱗翅類昆蟲之幼蟲有毒性

while cryB2 affected only the latter. cryB2基因對鱗翅類昆蟲之幼
蟲有毒性