| 查看: 2739 | 回复: 21 | |||
| 当前只显示满足指定条件的回帖，点击这里查看本话题的所有回帖 | |||
yuzhiming捐助贵宾 (知名作家)
|
[交流]
转基因作物，是否真的有效？看看最新PNAS的文章，抗BT的昆虫出现了。已有19人参与
|
||
|
http://www.news.cornell.edu/stories/Aug11/BtLooper.html 来自cornell大学的研究小组首次发现抗BT的昆虫。 Aug. 29, 2011 Researchers identify how insects resist Bt pesticides Ping Wang Cabbage looper larvae, Trichoplusia ni, feeding on transgenic broccoli plants expressing an insecticidal protein (Cry1Ac) from the biological pesticide Bacillus thuringiensis (Bt). By Krishna Ramanujan For the first time, researchers have identified how cabbage looper caterpillars in the field develop resistance to the bacterium Bacillus thuringiensis (Bt), which naturally occurs in the soil and on plants and has been developed into the most successful and widely used biological insecticide. When ingested, the insecticidal toxins in Bt kill insects by destroying their guts. Insects in the field develop resistance to it, however, via a genetic mechanism that alters a toxin receptor in the insect's gut, two Cornell researchers have discovered. The receptor belongs to a class of digestive enzymes called aminopeptidase N (APN), two of which undergo changes when cabbage loopers develop resistance to Bt on crops. Under normal circumstances, the Bt toxin Cry1Ac, which is a caterpillar-specific toxin, binds to an enzyme called APN 1 along the wall of the insect's gut, where the toxin destroys the gut lining. But when cabbage loopers develop resistance, APN 1 significantly decreases while another aminopeptidase, APN 6, which does not bind to Bt, significantly increases, allowing the insect to properly digest food and Bt without harm. "If an insect loses an aminopeptidase N, you will expect to see an negative effect on the physiology of the insect gut," said Ping Wang, associate professor of entomology and senior author of the paper published online in the Aug. 15 issue of the Proceedings of the National Academy of Sciences. Kasorn Tiewsiri, a postdoctoral associate in Wang's lab, is the paper's lead author. "To compensate for the loss of the enzyme APN 1, the activity of APN 6 jumps up high, and that allows the insect to perform a normal digestive process, where Bt no longer binds to the gut," Wang added. Organic farmers use Bt as a key weapon against insects, and crops genetically engineered with insecticidal Bt genes are now sown on 59 million hectares (more than 145 million acres) worldwide. Farmers first reported Bt resistance in the field 20 years ago. Since then, researchers have uncovered a number of mechanisms for resistance in insects in the lab, but then learned that lab insects, which don't face the same stressors as field insects, develop different tactics for overcoming Bt. In this study, Wang and Tiewsiri obtained cabbage loopers from greenhouses in British Columbia that were resistant to Bt and crossed them with a lab strain that had no resistance. The progeny carried the isolated Bt-resistant trait from their field-stressed parent. The researchers then used that line of cabbage loopers to conduct biochemical, proteomic and molecular studies. Next, the researchers plan on trying to identify which gene mutates in the Bt-resistant insects, how that gene controls the expression of targeted proteins, and uncover resistance mechanisms to other Bt toxins, as many varieties are used in agriculture. The researchers hope their studies will lead to new management strategies for Bt-resistant insects, Wang said. The study was funded by the U.S. Department of Agriculture's National Institute of Food and Agriculture. ## [ 来自科研家族 珊瑚岛 ] |
回复此楼» 本帖已获得的红花（最新10朵）
hycm863» 猜你喜欢
之前让一硕士生水了7个发明专利，现在这7个获批发明专利的维护费可从哪儿支出哈？
已经有5人回复
-
博士读完未来一定会好吗
已经有29人回复
-
博士申请都是内定的吗？
已经有5人回复
-
到新单位后，换了新的研究方向，没有团队，持续积累2区以上论文，能申请到面上吗
已经有12人回复
-
投稿精细化工
已经有4人回复
-
高职单位投计算机相关的北核或SCI四区期刊推荐，求支招！
已经有4人回复
-
导师想让我从独立一作变成了共一第一
已经有9人回复
-
读博
已经有4人回复
-
JMPT 期刊投稿流程
已经有4人回复
-
心脉受损
已经有5人回复
大鹏鸟100
木虫 (著名写手)
- 应助: 0 (幼儿园)
- 金币: 1846.1
- 红花: 5
- 帖子: 1259
- 在线: 260.4小时
- 虫号: 123455
- 注册: 2005-12-05
- 性别: GG
- 专业: 肿瘤复发与转移
22楼2013-07-20 23:57:15
jhu132llh
荣誉版主 (知名作家)
大洪
- 应助: 63 (初中生)
- 贵宾: 1.07
- 金币: 11622.1
- 散金: 796
- 红花: 30
- 沙发: 1
- 帖子: 5128
- 在线: 317小时
- 虫号: 1095066
- 注册: 2010-09-10
- 性别: GG
- 专业: 生殖生物学
- 管辖: 动植物
2楼2011-08-30 15:51:33
yangsh_nj
木虫 (著名写手)
- 应助: 97 (初中生)
- 金币: 4396.9
- 散金: 9795
- 红花: 23
- 帖子: 1763
- 在线: 1493小时
- 虫号: 1373354
- 注册: 2011-08-19
- 专业: 运动生理学
3楼2011-09-03 08:25:48
yyk81
木虫 (正式写手)
- 应助: 14 (小学生)
- 金币: 4072.9
- 红花: 1
- 帖子: 936
- 在线: 45.4小时
- 虫号: 1387477
- 注册: 2011-09-02
- 专业: 生物大分子结构与功能
4楼2011-09-04 10:25:29