基因改造農作物 黃金米 科研人員研發呈橙黃色或金黃 色的「黃金米」。黃金米的穀粒含有 β-胡蘿蔔素。科研人員將來自粟米 的八氫番茄紅素合成酶的基因和來 自某種細菌的胡蘿蔔素脫氫酶的基 因植入大米中，增加β-胡蘿蔔素。 β-胡蘿蔔素可以在人體內，根據需 要轉化為維他命A。維他命A是人類 視覺系統和維持免疫系統健康的重 要營養。 粉紅菠蘿 這品種的菠蘿經過基因改造， 加入一個來自柑桔的酶的基因，以 馨加菠蘿的番茄紅素；同時在改造 過程中，抑制菠蘿中兩個使番茄紅 素轉化成其他胡蘿蔔素的基因，令 菠蘿不會變黃。這款果肉和外皮呈 粉紅色的「粉紅菠蘿」，除了保留了 傳統菠蘿的營養價值外，相比於傳 統菠蘿，粉紅菠蘿更加鮮甜多汁， 酸味較少，並且擁有獨特的味道。 紫色番茄 為增加番茄的花青素，科研人 員發現金魚草的兩個基因可以製造 誘發花青素生物合成的轉錄因子， 所以將這兩個基因植入番茄內，令 番茄製造花青素。由於番茄所製造 的花青素含量增加，所以「紫色番 茄」的果實呈深紫色。花青素是一種 強效的抗氧化劑，能夠幫助改善血 管功能、降低炎症和促進新陳代謝。 從以上例子可見，基因改造食 物的技術能更精準地提高農作物的 營養價值。例如︰黃金大米含有更 多的維他命A，有助解決菲律賓、印 尼和孟加拉等發展中國家的人民缺 乏維他命A的問題。 增營養產量儲存期 香港大學生物科學學院與法國 研究團隊合作，改造番茄基因， 令其維他命E含量提高近5倍， 增強抗氧化功效。有研究人員 改造乳牛基因，使其產出的牛奶乳 糖含量降低，以便適合乳糖不耐症 患者飲用。通過抑制天門冬酰胺， 令油炸後的基因改造馬鈴薯減少釋 出致癌物——丙烯酰胺至50-75%。 基因改造農作物主要為了增強 對疾病、蟲害和除草劑的抵抗力， 使它們能夠適應不利生長環境，增 加產量。美國一種基因改造三文 魚，可在寒冷環境中持續分泌生長 激素，將成長期由原本的30個月縮 短至約18個月。科研人員將巴斯德 氏桿菌植入B.t.粟米和B.t.棉花，令它 們能自行產生對某些昆蟲有毒的蛋 白質，以防治害蟲，提升產量。 傳統蘋果和馬鈴薯容易因褐變 問題而被丟棄。科研人員透過基因 改造技術，抑制多酚氧化酶的酵素 發生作用，令蘋果和馬鈴薯削開或 去皮後能較長時間保持不變色，並 且不會因儲存受擠壓而呈現褐色或 黑斑，有助延長儲存期，減少浪費。 破壞生態環境 然而，基因改造技術仍面對不 少挑戰。基因改造作食物可能對生 態系統產生影響。例如︰抗除草劑 作物的廣泛種植可能導致除草劑抗 性雜草的出現，進而需要使用更多 除草劑。基因改造食物的推廣可能 導致農田出現單一種植模式。單一 作物的種植使農業系統對病害、害 蟲和氣候變化的抵抗能力下降，從 而降低農作物的生物多樣性。 導致基因轉移 基因改造農作物的花粉和種 子可能會意外地傳播到鄰近田野， 令到傳統品種的改變，特別是如果 抵受除草劑的基因傳到其他植物， 這些植物可能獲得抗除草劑的特 性，導致超級雜草的出現。基因改 造生物更會造成基因污染，影響自 然生態的平衡。基因改造生物有機 會成為入侵性物種，從而排擠甚至 淘汰其他自然物種。例如︰歐洲鯉 魚被引進澳洲美利河流域，因其繁 殖能力高和適應力強，排擠了原生 魚類，迅速成為該流域河魚物種的 90%。所以科學家只能修改歐洲鯉 魚的基因，令其只能繁殖雄性鯉魚。 食物標籤欠完善 儘管科學界普遍認為基因改造 食物是安全的，但部分消費者仍持 懷疑態度，擔心其潛在的健康風 險。基因改造工程可能引入一些本 來不會引起過敏反應的成分，從而 帶來新的過敏源。例如︰有科研人 員發現，一種基因改造大豆曾被植 入可引致過敏反應的巴西堅果基 因。如果對堅果過敏的患者不慎吃 了該大豆，就會產生過敏反應。這 事件帶出基因改造食物的食物標籤 制度欠缺監管。 在香港，基因改造食物的標籤 和安全問題一直是公眾關注的焦 點。根據香港食物安全中心的資 料，現時在香港市面上出售的基因 改造食物均已通過風險評估，被認 為與非基因改造食物一樣安全。然 而，現時各地政府對基因改造食物 標籤的政策均有不同。例如：香港 和加拿大均採用自願性標籤制度。 中國、美國、韓國和澳洲等國家則 推行強制性標籤制度。無論食物標 籤制度如何，消費者都應該有知情 權，了解基因改造食物的成分和營 養價值，從而選擇吃與不吃。 隨着科技的進步，基因改造技 術將變得更精確和高效。中國農業 農村部最近批准了多個轉基因粟米 和大豆品種的商業化生產，這標誌 着生物育種產業化的加速。這些轉 基因作物將有助提高農作物產量和 抗病性。基因改造食物在現代農業 中扮演着重要角色，有望為全球糧 食安全和營養改善作出更大貢獻。 小思考，大智慧 你認為保護自然環境和使用基因 改造技術之間有衝突嗎？ 參考答案 兩者之間可能存在一些衝突， 但也有協同作用。例如：基因改造 食物的廣泛種植影響生物多樣性。 基因改造作物的花粉和種子可能與 傳統作物交叉授粉，導致基因污 染。但是，基因改造食物的高產量 可以減少對農地的需求。耐旱或耐 鹽的基因改造農作物，幫助農業適 應氣候變化。只要平衡基因改造技 術應用的好處及對環境的保護，便 可推動農業可持續發展。 星島教室 生物科技與環保 葉穎琦 中華基督教會 何福堂小學 主任 作者介紹 大家有沒有見過金黃色的 大米、粉紅色果肉的菠蘿和紫 色的番茄？這些都是基因改造 食物例子。「基因改造食物」 是指通過基因工程技術改變其 基因組成的食物。這些技術讓 科學家將特定的基因，從一種 生物轉移到另一種生物中，賦 予其新特性，從而令食物有更 好的質量和產量。 本欄，由教育評議會邀請資 深中小學老師、校長及大學講師 撰稿，旨在為學生提供多元化的 STEAM學習材料，引發學生探求知 識的興趣，將學習融入生活，培養 學生的世界觀、敏銳的觸覺、積極 學習的態度。 讀社論學 英文 Donald Trump decisively defeated Kamala Harris to become the second US president after Grover Cleveland in the late 19th century who made a comeback following a re-election loss. Given his four years in the White House, world leaders are familiar with his style, especially the so-called "America First" policy. He is expected to use his usual unconventional "deal making" approach to shake up global politics. However, the landscape today has considerably changed in the past four years. It remains to be seen whether his methods will yield unexpected results or impact. "America First" without ideological constraints Trump left the White House in early 2021 with unfavourable political legacy. He blackmailed the NATO and Europe to cut military spending, potentially undermining America's global alliances for leadership. He launched trade wars with China and Europe to avoid being "taken advantage of", severely disrupting free trade and globalization. He unilaterally scrapped the Iran nuclear deal, claiming it had "terrible loopholes", which damaged his country's credibility. He controversially ordered a drone strike in Iraq to kill Iranian General Qasem Soleimani of the Islamic Revolutionary Guard Corps, raising legal concerns. Believing climate change was a "hoax", he withdrew from the Paris climate agreement, disregarding the world's well-being. Trump's first term undoubtedly brought massive upheaval which many would prefer to forget. The concept behind is "America First" to make "disrespected" America "great again", setting aside ideological constraints and ignoring consistent long-term plans. This unpredictable approach once led to the unprecedented US-North Korea summit, a highlight that Trump himself proudly touted, though it left the international community at a loss. That's exactly why allies - or even rivals - felt relieved when the stable conventional politician Biden took office. The world today is quite different from four years ago, but the unpredictability that "Trump 2.0" may bring is still a major concern. The Russia-Ukraine war has united the US and Europe in a strong front against Vladimir Putin. Will Trump, who often pressured allies, weaken it? Can he bring an early end to the war? All remain to be seen. Moreover, under Biden administration's restrictions, Israel still unrestrainedly attacked Hamas and Hezbollah. Will Trump, who is strongly pro-Israel, intensify the attacks or even adopt a more aggressive policy toward Iran, potentially throwing the Middle East out of control? President Joe Biden has been unable to reverse the sharp deterioration of Sino-US relations during Trump's first term that many Hongkongers are concerned about. Trump once vowed to impose a 60 per cent tariff on all Chinese goods on his return to the White House. If so, how will Sino-US relations be effectively managed? Will global recovery come to a halt? Learning from past experience Trump's victory will certainly mean subtle shifts in relations with Europe, Russia and China as well as the Middle East and climate issues. Dealing with an unpredictable person with no principles is no easy task. Some argued that Trump did not involve the US in new wars during his first term, indicating he was not a bad president. Others, however, pointed out that countries had already dealt with "Trump 1.0" and learned his patterns to cope with any shock from "Trump 2.0". These are not unfounded. US friends and foes are realists who can adapt to Trump's ways by adjusting to situations. Following his victory declaration, wor ld l eaders qui ckly extended thei r congratulations, probably out of courtesy and necessity. Whether they like him or not, there is no choice. Looking ahead, this highly controversial politician will certainly create endless debates and challenges. The world will inevitably face political risks with him at the helm. Let's see how he reshapes geopolitics in the coming four years. 翻譯自11月7日《星島日報》社論 （http://std.stheadline.com/） unconventional (adj) —— 非常規的 blackmail (v) —— 敲詐 credibility (n) —— 信用 upheaval (n) —— 動盪 tout (v) —— 吹捧 realist (n) —— 現實主義者 helm (n) —— 掌舵 reshape (v) —— 重塑 political legacy —— 政治遺產 drone strike —— 無人機襲擊 ideological constraint —— 意識形態制約 subtle shift —— 微妙變化 China said it hopes for "peaceful coexistence" with the US under Donald Trump. "We will continue to approach and handle China-US relations based on the principles of mutual respect, peaceful coexistence and win-win cooperation," foreign ministry spokeswoman Mao Ning said. "Our policy toward the US has been consistent," she added. 1. The word _____ in the first paragraph is the opposite of "standard". 2. Donald Trump launched _____ wars with China and Europe to avoid being "taken advantage of". 3. In the passage, the word _____ means "boasted". 4. Trump will cause _____ shifts in relations with Europe, Russia and China. 5. According to the last paragraph, the world will be expecting _____ risks as Trump takes office. Answers 1. unconventional 2. trade 3. touted 4. subtle 5. political & Q A Vocabulary Useful Terms Did you know? Trump with average track record returns, world awaits reshape 翻譯︰George D6 侷芎 04.04.2025 星期五
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