2013年5月12日 星期日

研究顯示讓蚊子感染細菌可抗瘧疾/ Scientists develop 'superwheat'

Cambridge-based scientists develop 'superwheat'

Wheat stalks in field The scientists transferred some of the resilience of the ancient ancestor of wheat into modern varieties

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British scientists say they have developed a new type of wheat which could increase productivity by 30%.
The Cambridge-based National Institute of Agricultural Botany has combined an ancient ancestor of wheat with a modern variety to produce a new strain.
In early trials, the resulting crop seemed bigger and stronger than the current modern wheat varieties.
It will take at least five years of tests and regulatory approval before it is harvested by farmers.
Some farmers, however, are urging new initiatives between the food industry, scientists and government.
They believe the regulatory process needs to be speeded up to ensure that the global food security demands of the next few decades can be met, says the BBC's Tom Heap.
Primitive grains One in five of all the calories consumed round the world come from wheat.
But despite steady improvement in the late 20th century, the last 15 years have seen little growth in the average wheat harvest from each acre in Britain.
Just last month, cereal maker Weetabix announced that it would have to scale back production of some of its products due to a poor wheat harvest in the UK.
Now British scientists think they may have found the answer to increasing productivity again.
Around 10,000 years ago wheat evolved from goat grass and other primitive grains.
The scientists used cross-pollination and seed embryo transfer technology to transfer some of the resilience of the ancient ancestor of wheat into modern British varieties.
The process required no genetic modification of the crops.

研究顯示讓蚊子感染細菌可抗瘧疾

更新時間 2013年5月10日, 格林尼治標準時間13:21

蚊子
蚊子是瘧疾在人與人之間傳播的媒介
美國密歇根州立大學科學家發現,蚊子在感染一種細菌之後可以獲得抵抗瘧原蟲的能力,從而阻止瘧疾的傳播。
發表在最新一期《科學》雜誌上的研究結果顯示,瘧原蟲在感染了這種細菌的蚊子體內很難存活。
瘧疾是通過蚊子在人與人之間傳播的。這項最新研究成果有望讓蚊子獲得對瘧疾的免疫力,從而減少人類感染瘧疾的病例。
瘧疾是一種嚴重的全球疾病。據世界衛生組織估計,全世界每年感染瘧疾的人數高達2.2億人,其中有66萬人死亡。
美國密歇根大學科學家集中研究了很容易感染昆蟲的沃爾巴克菌種。這個菌種往往通過雌性昆蟲傳給下一代。對於一些昆蟲來說,沃爾巴克菌種可以大大增加雌性昆蟲的數量,從而有利於昆蟲的繁殖。
傳播的挑戰
沃爾巴克菌種可以殺死一些蝴蝶和瓢蟲的雄性胚胎,有時候還能生產只能與感染該菌種的雌性昆蟲交配的雄性昆蟲,甚至能夠讓一些雌性黃蜂在無需交配的情況下生產。
攜帶瘧疾的瘧蚊並不會自然地感染沃爾巴克菌。但是,科學家在實驗室讓瘧蚊暫時感染沃爾巴克菌,並且讓蚊子獲得了對瘧原蟲的免疫力。
科學家目前面臨的挑戰是,如何把這種暫時的感染傳播開來。科學家已經發現,有一個沃爾巴克菌種能夠在一種名叫Stephensi的瘧蚊中向下一代傳播。
倫敦衛生與熱帶病學院教授康維對這一研究結果表現了謹慎的樂觀。他說,感染沃爾巴克菌的雌性蚊子產蛋量較低,這意味著這種感染在自然界的傳播會比較困難。
此外,科學家目前只對一種瘧蚊獲得了突破,也就是主要在中東和南亞攜帶瘧疾的瘧蚊Stephensi,而非洲的Gambiae瘧蚊是更大的問題。
但是參加這項研究的科學家Zhiyong Xi博士對BBC說,他們會把同樣的技術運用於Gambiae瘧蚊。

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