Genetically modified food (GM food) Lesson 1, 2: Introduction of the GM food

Genetically modified food (GM food) In several thousands of years ago, people started to develop agricultural methods to improve plant quality and achieve better crop yield. The concept of the GM food is originated from the traditional cross-breeding. Both of the methods hopefully can improve the characteristic of agricultural products.

Figure of the advancement in methods of agricultural products improvement 1850s Cross pollination between varieties of the same species, e.g. wheat   1930s Hybridisation between different species and genus e.g. wheat + rye = triticale  1975 Cell fusion to overcome species barriers by combining individual plant cells  1985 DNA technology - modification of crop characteristics at the level of individual genes. 1850s – Cross pollination changed the characteristics of plants 1930s – Hybridisation became popularised 1975 – Cell fusion combined plant cells 1985 – DNA techniques drove plant modification into the gene level

The major weaknesses of traditional methods Traditional breeding usually involves random transfer of thousands of genes at one time to obtain the desired characteristics The process is slow and unpredictable 傳统植物生物技術 採用受控花粉授精的傳統植物繁殖技術有很多局限性。首先，有性雜交只能在同種或者有親屬關係的物種之間進行。這限制了人們用來加強某些需要特徵的基因源。第二，當兩株植物雜交後，每種都有約100 000個基因，兩株植物所有的基因堆在一塊。這有可能産生這樣一個問題，即後代植株既有從上代繼承所需特徵，也有不想有的特徵。因此，配種者必須花上數年一遍遍地進行"回交"，然後篩掉數以萬計的不想要的基因。傳統繁殖方式費時，有時長達12年。

GM method and traditional method The purposes of the GM method is boosting or weakening certain characteristics in a certain type of organism We can control organism’s characteristics through genetically modification The GM method is more accurate and efficient to control the organism’s characteristics than traditional method

The development of GM food The GM food developed in the 90s In 1983, the first transgenic plant of the world, a tobacco plant resistant to an antibiotic, appeared. In 1994, the first series of transgenic tomatoes with delayed maturation was introduced to the US market.

Common examples of GM food Crops New characters from genetically engineering Oilseed rape Improved quality of oil products, anti-herbicidal ability, new hybridity species from cross-breeding Maize (corn) Anti-pest,anti-herbicidal Potato Improved starch quality, anti-pest, anti-diseases, the process needed for improving and processing Tomato Delayed maturation period, the process needed for improving and processing

Common examples of GM food Crops New characters from genetically engineering Wheat Improved starch quality and anti-diseases Sugar beet Improved starch quality, anti-diseases and herbicides Apple Anti-herbicides and delayed the maturation period Field vegetables Anti-pests,new species derived from hybridity

Some main causes of developing the GM food Improve the characteristics of food – included yields, anti-pest and anti-herbicide species Crops with new qualities can be obtained – e.g. an improved nutritional status, better favors, easier to process or use of lesser amount of additives. Improvement of our environment – reduce the use of insecticides or herbicides for pest control of crops. Improving processing characteristics so as to reduce wastage and costs.

Genetically engineered agricultures products Lesson 3, 4: the production techniques for the GM food

Basic concepts Genes are hereditary materials. Genes are composed of Deoxyribose Nucleic Acid (DNA). DNA is in every cell of your body. It contains the information needed to construct and operate a human body. The cell of each plant or animal contains more than ten millions of genes

DNA製造RNA製造蛋白質 分子生物學的最基本原理就是DNA製造RNA，然後RNA製造蛋白質 ; 不同的蛋白質構成不同細胞，無數的細胞構成了人體。所以，最基本的生命訊息就藏在一個細胞的細胞核中的30億個DNA密碼中。只要了挖這個如天文數字的「人類條碼」，你就可以徹底了解人類這種生物了。 通常這個DNA分子是雙螺旋立體結構，只由A、T、G、C四個核苷酸組成。分子生物學家在研究的時間，習慣只寫上單股的DNA序列。這是因為只寫出一股序列，另外一股序列就可以推斷出來了。一邊是G，另外一邊一定是C ; 一邊是A，另外一邊一定是T。所以，你明明知道DNA分子是一種雙螺旋狀構造，但往往這些分子生物專家談論DNA分子序列只談一邊。

Genes carry biological information necessary to produce a protein(s) that determines the characteristics of an organism. Proteins are major cell structures that operate most of the functions for human body to live. Protein is a polymer synthesized from units of amino acids.

DNA sequence is the genetic code Continually lengthening protein chain

The purpose of genetically modification is using recombinant DNA to enhance or eliminate certain characteristics of certain organisms. We can control the characteristics of organisms through modifying genes. 1970年H.O. Smith 和 K.W. Wilcox 發現具選擇性切斷DNA的限制酶 (Restriction enzyme) 。。在1972年，Paul Berg成為首位成功實現DNA體外重組技術的生物科研專家。他利用限制酶切斷 DNA，再用連接酶 (Ligase) 將兩斷 DNA 接合起來把DNA 分子重組。

Examples of Genetically modification techniques Ballistic impregnation: It involves sticking the genes on gold particles and hit on the plant cell. Some plant cells would take up the genes from the gold particles and then re-grow. 基因槍或粒子直接導入技術原理為利用高密度微粒子 (microprojectile) 如黃金微粒，鎢粒子等，先覆以基因物質，再藉由火藥點火造成之推動力或高壓氦氣產生之推動力，打入植物細胞或組織中。此法之優點在於完全不受植分類地位之限制，且可將基因打入完整可再生之植物細胞，故可避免如原生質再生之困難。一般選凙用以打入外來基因之材料多為未成熟胚 (immature embryo)，或其他可再生之培養體如嫩葉部、胚原癒合組織 (embryogenic callus)、或懸浮培養之細胞等，可以減少長期組織培養造成變異 (variation)之問題。

2) Use of soil bacteria as a go-between: The soil bacteria Agrobacterium can change the genetic material of plant cells so that outgrowths are formed on the plant. The desired genes transferred to this bacteria is then incorporated into plant cells for producing the desired genetic characteristics. 利用農桿菌 (agrobacterium) 為轉殖基因媒介之材料是最被廣泛使用之方法。這一媒介可令欲轉殖之基因藉此菌之質體先攜入細菌內，再將此菌接種入植物組織完成感染從而達到基因殖入之目的。

Tomatoes with delayed maturation period Examples of GM food: Tomatoes with delayed maturation period 1990年英國科學家Grierson比較已成熟與未成熟的 蕃茄，發現在成熟的蕃茄中有六個基因是未成熟的蕃茄所沒有的。 箇中的基本原理是把有關的基密碼程序作反向編排 (reverse) –以產生反義RNA (antisense RNA) – 來抑制該基因的表現例如抑制細胞壁軟化從而應用於延遲蕃茄、瓜類等果實的成熟期。此類蕃茄巳在1994年美國的市場出現。

How to produce genetically modified crops? Genetically modified corns (anti-pest)

The gene coded the anti-pest proteins 1. Bacillus thuringienesis is a bacterium that can produce a natural pesticide called Bt protein. 2. The gene coded for the Bt protein is isolated from the bacterium. The gene coded the anti-pest proteins 蘇雲氏金桿力菌(又稱蘇力菌)(Bacillus thuringiensisc var. kurstaki) 是自然界產生對昆蟲有毒害的一種土壤微生物，其於產生孢過程會產生Delta內毒素，這種結晶疍白對鱗翅目 (Lepidoptera) 昆蟲有劇毒，1961年即被利用當生物性殺蟲劑。將此基因直接轉殖到欲防蟲的植物寄生主內，讓植物直接產生毒素以防蟲是最一勞永逸的方法，其具有生物性殺蟲劑所無的優點： a.內毒素不會因光線或環境的溫度而分解以致失去殺蟲效果。 b.在植物體內不斷生產製造，而不必像生物劑需施用。 因此基因轉殖利用於抗蟲上有減少污染以及省錢省工的目的，在美國為防除棉花上的蟲害每年花費4億美金之多。 目前此有(蘇力菌)的變種對鞘翅目 (Coleoptera)、雙翅目 (Diptera) 等昆蟲具殺蟲效果。

3. The isolated gene is then combined with a plasmid to form a recombinant DNA by using recombinant DNA techniques.

4. The recombinant DNA is put into another species of bacteria for producing more recombinant DNA.

5. Transfer the recombinant DNA in another bacterial species to produce more recombinant genes.

6. The bacteria is incubated with plant cell and the recombinant DNA will be transferred from bacteria cells to plant cells.

7. The plant cell develops to a plantlet.

8. Finally, The new plant is tested for the presence of the Bt protein 8. Finally, The new plant is tested for the presence of the Bt protein. A genetically modified plant can be successfully created if the testing is confirmative GM crop

The controversy of the GM food Supporting!! Opposing!! Lesson 5, 6: The contrversy of the GM food

“ GM crops can improve the nutritional value, the taste and the crop yields. The amount of pesticides used can also be decreased which prevents environmental pollution to the natural environment.” Supporters

“ GM crops can solve the problem of the Food Crisis due to the growth in population in the future.” Supporters

“The developmental history of GM crops is too short “The developmental history of GM crops is too short. It has not undergone sufficient tests, which may be harmful to human health and ecological environment. ” 至今還未有科學家表明基因改造食品是絕對安全。 因為科學家利用植物病毒為外來基因的載體， 把基因送入具再生能力的植物細胞中。 而當中潛在的風險包括寄生在植物細胞核內的病毒變種， 人類吃後可能會患上難以治癒的疾病， 影響生態環境。 Opponents

“ There is no so-called ‘the Food Crisis’ in the world “ There is no so-called ‘the Food Crisis’ in the world. The problem for us to concern is ‘wasting of food’ and ‘uneven distribution of food’. GM crops would only be bring profits to biotechnology companies and agricultural businesses.” “世界農糧組織的調查己發現全球糧食的年產量巳足以滿足各國人口需要，至於個別地方區出現的飢荒只是出於戰爭貧窮或分配不均根本與產量問題無關。” --- 綠色和平 Opponents

GM (anti-pest) corn Starlink The GM food Issue Case: GM (anti-pest) corn Starlink Lesson 5,6: The controversy of the GM food

In 1997, a company named Plant Genetic Systems (now named Aventis) registered a GM anti-pest corn (Starlink) at EPA（The Environmental Protection Association of the United States）. EPA in the US only approved the corn for animal feeds at that time, as the conclusion on whether Starlink would cause human allergy has not been confirmed yet. EPA in the US has requested Aventis to notify the farmers to prevent mixing Starlink with human food. Lesson 5,6: The controversy of the GM food

2 years later, it is revealed that processed food of some popular brands contained compositions of Starlink and initiate a global retrieving action. More than 300 types of products composed of corns are involved. Meanwhile, some consumers have allergic responses after taking food containing Starlink. Some peasants also sue the Aventis as Starlink is mixed in the composition of their seeds. Then the Aventis made compensation settlement with 17 states in the US, the amount was between 100 million to one billion dollars. Lesson 5,6: The controversy of the GM food

The GM food Issue Questions for self-reflection: Through understanding the viewpoints of supporters and opponents, and studying some cases, what is your opinion about the issue? What are your suggestions on establishing safety measures on the GM food?