Featured Research

from universities, journals, and other organizations

Texas A&M Researchers Reset Bacterial Clocks

Date:
September 1, 2000
Source:
Texas A&M University
Summary:
In the Aug. 4 issue of the journal Science, Texas A&M researchers report their identification of a gene - called the cikA gene - that codes for a protein important in resetting the circadian clock in a species of cyanobacteria.

COLLEGE STATION - As any world traveler can tell you, jet lag is a real drag. Travelers to Europe, for instance, know it takes about three days before they can go to sleep when it's dark and wake up when the sun rises.

Jet lag is the most obvious evidence that people have an internal timing device capable of telling time without cues from the environment, says Susan Golden, a biologist at Texas A&M University. Only when your clock resets itself after a few days can you sleep and wake at the right times.

Humans aren't the only organisms with these internal, or circadian, clocks. Plants and animals also have internal timing devices and about 10 years ago, scientists were stunned to learn that simple, single-celled bacteria had biological clocks as well. Even more surprising, says Golden, was the realization that the bacterial clock does everything the clocks of its more complicated plant and animal counterparts do.

In the Aug. 4 issue of the journal Science, Golden's research group reports their identification of a gene - called the cikA gene - that codes for a protein important in resetting the circadian clock in a species of cyanobacteria.

The Texas A&M researchers mutated bacteria by introducing a transposon, or a jumping gene, into the bacteria. This jumping gene inserted itself randomly into a cell, yielding a collection of randomly mutated bacteria, each of which produces its own mutant colony. The researchers tested each colony, looking for a defect in the bacterial clock and the inserted transposon served as a tag, indicating which gene was mutated.

The cyanobacteria were genetically engineered to give off light, or bioluminescence, using a luciferase gene that codes for the enzyme that produces light. By measuring the amount of light given off by the bacteria, the researchers indirectly measured the expression of a gene controlled by the clock. A plot of the amount of light given off by the normal bacteria shows a peak of light emission every 24 hours, followed 12 hours later by a trough, when little or no light was given off.

The researchers found that if they varied the time when the bacteria with the mutant cikA gene saw light and dark, the mutant bacteria did not recognize that environmental cue and continued peaking and troughing as though they had not seen a change in their schedules. The mutated bacteria could not reset their clocks and also thought a day was two hours shorter than it actually is.

These facts, says Golden, provide strong evidence that the gene and the protein it codes for play a significant role in resetting the bacterium's circadian clock.

An organism's ability to reset its circadian clock is important, says Golden, because day length changes during the year, thereby changing the environment so that sunrise and sunset are at different times each day.

"By having an internal clock that is somewhat flexible," says Golden, "you can go to different locations and have your clock synchronized with your environment. And even staying in one location, you can have your clock synchronized appropriately at different times of the year."


Story Source:

The above story is based on materials provided by Texas A&M University. Note: Materials may be edited for content and length.


Cite This Page:

Share This




More Plants & Animals News

Friday, July 25, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Boy Attacked by Shark in Florida

Boy Attacked by Shark in Florida

Reuters - US Online Video (July 24, 2014) An 8-year-old boy is bitten in the leg by a shark while vacationing at a Florida beach. Linda So reports. Video provided by Reuters
Powered by NewsLook.com
Goma Cheese Brings Whiff of New Hope to DRC

Goma Cheese Brings Whiff of New Hope to DRC

Reuters - Business Video Online (July 24, 2014) The eastern region of the Democratic Republic of Congo, mainly known for conflict and instability, is an unlikely place for the production of fine cheese. But a farm in the village of Masisi, in North Kivu is slowly transforming perceptions of the area. Known simply as Goma cheese, the Congolese version of Dutch gouda has gained popularity through out the region. Ciara Sutton reports. Video provided by Reuters
Powered by NewsLook.com
Tyrannosaur Pack-Hunting Theory Aided By New Footprints

Tyrannosaur Pack-Hunting Theory Aided By New Footprints

Newsy (July 24, 2014) A new study claims a set of prehistoric T-Rex footprints supports the theory that the giant predators hunted in packs instead of alone. Video provided by Newsy
Powered by NewsLook.com
Bill Gates: Health, Agriculture Key to Africa's Development

Bill Gates: Health, Agriculture Key to Africa's Development

AFP (July 24, 2014) Health and agriculture development are key if African countries are to overcome poverty and grow, US software billionaire Bill Gates said Thursday, as he received an honourary degree in Ethiopia. Duration: 00:36 Video provided by AFP
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:
from the past week

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