文章来源:未知 文章作者:meng 发布时间:2010-11-23 02:23 字体: [ ]  进入论坛

Binghamton University researchers recently revived(复活,再生) ancient bacteria trapped for thousands of years in water droplets1(水滴) embedded2(嵌入,固定) in salt crystals. For decades, geologists3(地质学家) have looked at these water droplets — called fluid inclusions(液体包裹体) — and wondered whether microbes could be extracted from them. Fluid inclusions have been found inside salt crystals ranging in age from thousands to hundreds of millions years old.

But there has always been a question about whether the organisms cultured from salt crystals are genuinely ancient material or whether they are modern-day contaminants(污染物) , said Tim Lowenstein, professor of geological sciences and environmental studies at Binghamton.

Lowenstein and Binghamton colleague J. Koji Lum, professor of anthropology5(人类学) and of biological sciences, believe they have resolved this doubt. And they've received $400,000 from the National Science Foundation to support further research on the topic.

Lowenstein's team, which has been pursuing this problem for years, began by examining the fluid inclusions under a microscope. "Not only did we find bacteria, we found several types of algae6 as well," he said. "The algae actually may be the food on which the bacteria survive for tens of thousands of years."

When Lum got involved, the researchers began to wonder about the DNA7 of the organisms they were finding.

"You have a little trapped ecosystem," Lum said. "Some of these guys are feeding on other ones trapped in this space. The things that aren't alive in there, their DNA is still preserved."

Lum's graduate student Krithivas Sankaranarayanan reviewed existing literature on ancient DNA and helped to develop a protocol8 for use with Lowenstein's samples.

"We have these samples going back from the present to over 100,000 years in one exact location," Lum said. "So Tim can look at the salinity9(盐度) and reconstruct ancient climates. Now we're looking at the DNA from bacteria, the algae, the fungi10 and what was living in those waters and how those things changed over time. We have a view of all the different organisms that were in the lakes at the time these inclusions(包含,内含物) were formed."

The researchers sequence the DNA and culture the bacteria they find. Then it's time to think big. Lum's most optimistic view of the project goes like this: "It's possible that we can observe organisms evolving and see how they're reacting to climate change over geologic4 time."

The samples Lowenstein works with are drawn11 from Death Valley and Saline Valley in California as well as from sites in Michigan, Kansas and Italy.

Temperatures at these locations may have reached 130 degrees Fahrenheit12 in the past, and the pockets of water trapped inside the rocks are generally very salty.

The environment may sound harsh — in fact, it's among the most extreme on Earth — but the creatures that survive there are tough.

"These are some of the hardiest13 beasts on the planet," Lum said. And the conditions inside these water droplets are ideally suited to preserving DNA.

"They're like time capsules," Lowenstein agreed.


1 droplets 3c55b5988da2d40be7a87f6b810732d2     
n.小滴( droplet的名词复数 )
  • Droplets of sweat were welling up on his forehead. 他额头上冒出了滴滴汗珠。 来自辞典例句
  • In constrast, exhaled smoke contains relatively large water droplets and appears white. 相反,从人嘴里呼出的烟则包含相当大的水滴,所以呈白色。 来自辞典例句
2 embedded lt9ztS     
  • an operation to remove glass that was embedded in his leg 取出扎入他腿部玻璃的手术
  • He has embedded his name in the minds of millions of people. 他的名字铭刻在数百万人民心中。
3 geologists 1261592151f6aa40819f7687883760a2     
地质学家,地质学者( geologist的名词复数 )
  • Geologists uncovered the hidden riches. 地质学家发现了地下的宝藏。
  • Geologists study the structure of the rocks. 地质学家研究岩石结构。
4 geologic dg3x9     
  • The Red Sea is a geologic continuation of the valley.红海就是一个峡谷在地质上的继续发展。
  • Delineation of channels is the first step of geologic evaluation.勾划河道的轮廓是地质解译的第一步。
5 anthropology zw2zQ     
  • I believe he has started reading up anthropology.我相信他已开始深入研究人类学。
  • Social anthropology is centrally concerned with the diversity of culture.社会人类学主要关于文化多样性。
6 algae tK6yW     
  • Most algae live in water.多数藻类生长在水中。
  • Algae grow and spread quickly in the lake.湖中水藻滋蔓。
7 DNA 4u3z1l     
(缩)deoxyribonucleic acid 脱氧核糖核酸
  • DNA is stored in the nucleus of a cell.脱氧核糖核酸储存于细胞的细胞核里。
  • Gene mutations are alterations in the DNA code.基因突变是指DNA密码的改变。
8 protocol nRQxG     
  • We must observe the correct protocol.我们必须遵守应有的礼仪。
  • The statesmen signed a protocol.那些政治家签了议定书。
9 salinity uYvx9     
  • In the sea water sampled the salinity is two parts per thousand.在取样的海水中,盐度为千分之二。
  • In many sedimentary basins the salinity of the formation water increases with depth or compaction.在许多沉积盆地中,地层水的含盐量随深度或压实作用而增高。
10 fungi 6hRx6     
  • Students practice to apply the study of genetics to multicellular plants and fungi.学生们练习把基因学应用到多细胞植物和真菌中。
  • The lawn was covered with fungi.草地上到处都是蘑菇。
11 drawn MuXzIi     
  • All the characters in the story are drawn from life.故事中的所有人物都取材于生活。
  • Her gaze was drawn irresistibly to the scene outside.她的目光禁不住被外面的风景所吸引。
12 Fahrenheit hlhx9     
  • He was asked for the boiling point of water in Fahrenheit.他被问到水的沸点是华氏多少度。
  • The thermometer reads 80 degrees Fahrenheit.寒暑表指出华氏80度。
13 hardiest 498a5cbf45862cc3cd016490acc06453     
能吃苦耐劳的,坚强的( hardy的最高级 ); (植物等)耐寒的
  • This trip will season even the hardiest traveller. 这个旅行会让最坚硬的旅行者适应。
TAG标签: water DNA bacteria