【资料】痢疾寄生虫通过吞噬活细胞来攻击肠道
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Dysentery parasite attacks gut by eating cells alive
痢疾寄生虫通过吞噬活细胞来攻击肠道
这是一种能致命的疟疾。每年都有超过100，000人死于阿米巴痢疾，这种状况大多发生在公共卫生条件较差的发展中国家。但是仅有10%的携带阿米巴痢疾的患者会表现出症状，让科学家们迷惑的是寄生虫们在身体中是如何捕食的。现在，弗吉尼亚大学的凯瑟琳?罗尔斯顿和威廉?彼得以及夏洛茨维尔发现阿米巴痢疾有种独特且可怕的策略。它首先啃噬肠壁，将活细胞撕开并吞噬，并在此过程中杀死活细胞。
It's a killer amoeba. More than 100,000 people die each year from amoebic dysentery, mostly in developing countries where sanitation is poor. But only 10 per cent of people who carry the amoebic parasite ever show symptoms, leaving scientists mystified as to how it preys on the body.
Now Katherine Ralston and William Petri of the University of Virginia, Charlottesville, have found that Entamoeba histolytica has a unique – and gruesome – strategy. It gnaws away at the gut wall, ripping and ingesting chunks off living cells, killing them in the process.
It's "purely malevolent", says Michael Blennerhassett of Queen's University in Ontario, Canada, because the amoeba aren't interested in the cells once they're dead. This suggests they don't need to eat them for the nutrients they contain, says Blennerhasset, who was not involved in the study. "This is a previously unsuspected method of attack."
Ralston and Petri labelled mouse intestines using fluorescent dyes, in order to follow their fate. Most amoebas kill cells by attaching themselves to them, but E. histolytica tears at its targets. "We saw that the amoeba ingested bites of the fluorescent membranes of the intestinal cells," says Ralston. "They are impressively ravenous."
If E. histolytica is constantly grazing throughout the gut, it may be able to lurk inside a host for years without wreaking enough damage to cause inflammation or disease.
"The way it samples bits and pieces of the cell suggests this may be going on all the time, and only when a certain balance is broken does the disease set in," says Kris Chadee, a microbiologist from the University of Calgary in Alberta, Canada. "The parasite needs to attach to the cell to rip off little pieces, so if you could get blocking antibodies in the place where it attaches, that would be a potential target for drug development."
http://119.57.53.19/vom/info.aspx?t=0&p=&id=28958
痢疾寄生虫通过吞噬活细胞来攻击肠道
这是一种能致命的疟疾。每年都有超过100，000人死于阿米巴痢疾，这种状况大多发生在公共卫生条件较差的发展中国家。但是仅有10%的携带阿米巴痢疾的患者会表现出症状，让科学家们迷惑的是寄生虫们在身体中是如何捕食的。现在，弗吉尼亚大学的凯瑟琳?罗尔斯顿和威廉?彼得以及夏洛茨维尔发现阿米巴痢疾有种独特且可怕的策略。它首先啃噬肠壁，将活细胞撕开并吞噬，并在此过程中杀死活细胞。
It's a killer amoeba. More than 100,000 people die each year from amoebic dysentery, mostly in developing countries where sanitation is poor. But only 10 per cent of people who carry the amoebic parasite ever show symptoms, leaving scientists mystified as to how it preys on the body.
Now Katherine Ralston and William Petri of the University of Virginia, Charlottesville, have found that Entamoeba histolytica has a unique – and gruesome – strategy. It gnaws away at the gut wall, ripping and ingesting chunks off living cells, killing them in the process.
It's "purely malevolent", says Michael Blennerhassett of Queen's University in Ontario, Canada, because the amoeba aren't interested in the cells once they're dead. This suggests they don't need to eat them for the nutrients they contain, says Blennerhasset, who was not involved in the study. "This is a previously unsuspected method of attack."
Ralston and Petri labelled mouse intestines using fluorescent dyes, in order to follow their fate. Most amoebas kill cells by attaching themselves to them, but E. histolytica tears at its targets. "We saw that the amoeba ingested bites of the fluorescent membranes of the intestinal cells," says Ralston. "They are impressively ravenous."
If E. histolytica is constantly grazing throughout the gut, it may be able to lurk inside a host for years without wreaking enough damage to cause inflammation or disease.
"The way it samples bits and pieces of the cell suggests this may be going on all the time, and only when a certain balance is broken does the disease set in," says Kris Chadee, a microbiologist from the University of Calgary in Alberta, Canada. "The parasite needs to attach to the cell to rip off little pieces, so if you could get blocking antibodies in the place where it attaches, that would be a potential target for drug development."
http://119.57.53.19/vom/info.aspx?t=0&p=&id=28958
