Featured Research

from universities, journals, and other organizations

Microbes From 120,000-year-old Ice Sample Show Life's Tenacity

Date:
May 27, 2004
Source:
Penn State
Summary:
The discovery of millions of micro-microbes surviving in a 120,000-year-old ice sample taken from 3,000 meters below the surface of the Greenland glacier was announced by Penn State scientists at the General Meeting of the American Society for Microbiology.

University Park, Pa. -- The discovery of millions of micro-microbes surviving in a 120,000-year-old ice sample taken from 3,000 meters below the surface of the Greenland glacier was announced by Penn State scientists today (May 26) at the General Meeting of the American Society for Microbiology in New Orleans, La. The discovery may help to define the limits for life on Earth, as well as elsewhere in the universe, such as on cold planets like Mars.

Related Articles


According to Penn State's Vanya I. Miteva, research associate, and Jean E. Brenchley, professor of microbiology and biotechnology, the majority of the microbes they discovered in an ice-core sample taken from the glacier were less than 1 micron in size -- smaller than most commonly known bacteria, which range from 1 to 10 microns. In addition, a large portion of the cells appeared to be even smaller and passed through filters with 0.2-micron pores.

The scientists are interested in understanding how microbial life can be preserved in polar ice sheets for hundreds of thousands of years under stresses that include subzero temperatures, desiccation, high pressures, and low oxygen and nutrient concentrations. Because the ice was mixed with the ancient permafrost at the bottom of the glacier, the microbes could have been trapped there for perhaps millions of years.

"We are particularly interested in the formation of ultra-small cells as one possible stress-survival mechanism, whether they are starved minute forms of known normal-sized microbes or intrinsically dwarf novel organisms, and also whether these cells are able to carry on metabolic processes while they are so highly stressed," Miteva says.

Physiological changes that accompany the reduction of a cell's size may allow it to become dormant or to maintain extremely low activity with minimal energy.

"Many of these ice-core microbes are related to a variety of ultra-small microorganisms from other cold environments that have been shown to use different carbon and energy sources and to be resistant to drying, starvation, radiation, and other stress factors. Their modern relatives include the model ultra-micro bacterium Sphingopyxis alaskensis, which is abundant in cold Alaskan waters," Brenchley reports. She and Miteva are in the process of closely examining all the microbes they found in order to determine the identities and diversity of the species and to look for ones with novel functions.

The researchers used a variety of methods including repeated sample filtrations, electron microscopy and a modified technique of flow cytometry to quickly reveal the number of cells and to estimate their different sizes, DNA content, and other characteristics. Miteva and Brenchley discovered cells with many different shapes and sizes, including a large percentage that were even smaller than filter-pore sizes of only 0.2 microns.

"It appears that these ultra-small microbes often are missed in research studies because they pass through the finest filters commonly used to collect cells for analysis," Miteva says.

Scientists believe these dwarf cells belong to the "uncultured majority" because they are among the 99 percent of all microbes on Earth that never have been isolated and cultured for study. Obtaining such "isolates" is necessary in order to describe a new organism, study its cell size, examine its physiology, and assess its ecological role.

"We now know just the tip of the iceberg of all the microbes that exist on Earth, and it generally is believed that a large portion of these unknown microbes are very small in size," Miteva says.

"A major challenge is to develop novel approaches for growing some of these previously unculturable organisms," Brenchley says. "At present, no single established protocol exists and little is known about the recovery of these stressed and possibly damaged cells from a frozen environment that subjects them to severe conditions for long periods."

Some of the cells that Miteva and Brenchley were successful in cultivating required special conditions and up to six months to form initial colonies. The researchers discovered that these colonies grew more rapidly during further cultivation and that most continued to form predominantly small cells.

"Our study of the abundance, viability, and identity of the ultra-small cells existing in the Greenland ice is relevant to discovering how small life-forms can be; how cells survive being small, cold and hungry; and what new tricks we need to develop in order to cultivate these small cells," Miteva says. "This study is part of the continuing quest by microbiologists to overcome the current limitations of our methods and to answer the big question, 'What new microbes are out there and what are they doing?'"

This research was supported by the Department of Energy (Grant DE-FG02-93ER20117) and the Penn State Astrobiology Center (NASA-Ames Cooperative Agreement No. NCC2-1057).

More information and photos are available on the Web at http://www.science.psu.edu/alert/Brenchley5-2004.htm


Story Source:

The above story is based on materials provided by Penn State. Note: Materials may be edited for content and length.


Cite This Page:

Penn State. "Microbes From 120,000-year-old Ice Sample Show Life's Tenacity." ScienceDaily. ScienceDaily, 27 May 2004. <www.sciencedaily.com/releases/2004/05/040527080029.htm>.
Penn State. (2004, May 27). Microbes From 120,000-year-old Ice Sample Show Life's Tenacity. ScienceDaily. Retrieved October 26, 2014 from www.sciencedaily.com/releases/2004/05/040527080029.htm
Penn State. "Microbes From 120,000-year-old Ice Sample Show Life's Tenacity." ScienceDaily. www.sciencedaily.com/releases/2004/05/040527080029.htm (accessed October 26, 2014).

Share This



More Plants & Animals News

Sunday, October 26, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Deep Sea 'mushroom' Could Be Early Branch on Tree of Life

Deep Sea 'mushroom' Could Be Early Branch on Tree of Life

Reuters - Innovations Video Online (Oct. 24, 2014) Miniature deep sea animals discovered off the Australian coast almost three decades ago are puzzling scientists, who say the organisms have proved impossible to categorise. Academics at the Natural History of Denmark have appealed to the world scientific community for help, saying that further information on Dendrogramma enigmatica and Dendrogramma discoides could answer key evolutionary questions. Jim Drury has more. Video provided by Reuters
Powered by NewsLook.com
Black Bear Cub Goes Sunday Shopping

Black Bear Cub Goes Sunday Shopping

Reuters - Light News Video Online (Oct. 23, 2014) Price check on honey? Bear cub startles Oregon drugstore shoppers. Rough Cut (no reporter narration). Video provided by Reuters
Powered by NewsLook.com
Dances With Wolves in China's Wild West

Dances With Wolves in China's Wild West

AFP (Oct. 23, 2014) One man is on a mission to boost the population of wolves in China's violence-wracked far west. The animal - symbol of the Uighur minority there - is under threat with a massive human resettlement program in the region. Duration: 00:41 Video provided by AFP
Powered by NewsLook.com
Breakfast Debate: To Eat Or Not To Eat?

Breakfast Debate: To Eat Or Not To Eat?

Newsy (Oct. 23, 2014) Conflicting studies published in the same week re-ignited the debate over whether we should be eating breakfast. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins