Featured Research

from universities, journals, and other organizations

Glowing Cyanobacteria Gives Researchers New Clues To Circadian Rhythms

Date:
September 7, 1998
Source:
National Science Foundation
Summary:
Three genes essential to circadian rhythms in cyanobacteria, the simplest organisms known to have such "internal clocks," have been identified by scientists funded by the National Science Foundation (NSF). The research, by biologists Carl Johnson of Vanderbilt University and Susan Golden of Texas A & M University, is published in last week's issue of Science.

Three genes essential to circadian rhythms in cyanobacteria, the simplest organisms known to have such "internal clocks," have been identified by scientists funded by the National Science Foundation (NSF). The research, by biologists Carl Johnson of Vanderbilt University and Susan Golden of Texas A & M University, is published in last week's issue of Science.

Related Articles


"Circadian rhythms enable organisms to react to the two most predictable events on Earth -- day and night," said Shil DasSarma, program manager in NSF's division of molecular and cellular biosciences, which funded the research. The clocks that power circadian rhythms are complex mechanisms of chemical reactions that control the timing of events in cells.

To identify genes involved in the circadian rhythm process, the researchers used a gene for a bioluminescent enzyme to indicate the activity of another gene that they knew the circadian clock controlled. Whenever the circadian clock was working, the cell made bioluminescent proteins rhythmically-causing the cell to glow with a predictable pattern throughout the day. This made it easier for researchers to identify which cyanobacteria had working circadian clocks, since they were the ones glowing like fireflies.

Once they could spot cyanobacteria without such clocks, or whose clocks did not keep the correct time, the researchers could find which genes were not functioning properly. What they found was a cluster of three genes, which they named kaiABC, after the Japanese word for cycle, "kai". KaiABC contains the information that the cell will use to make proteins called KaiA, B and C, respectively. The Kai proteins, they theorize, are integral components of the feedback loop that drives the circadian clock.

"The expression of KaiC is critically important for setting the phase of the clock," said Golden. The researchers found that the levels of kaiC gene expression increase during daytime and decrease during nighttime. But an overabundance of KaiC protein through either period can measurably shift the timing of the clock. Adding too much KaiC while the amount of the protein is naturally rising, daytime, causes the clock to advance. Whereas too much KaiC when the levels ought to be falling, nighttime, causes the clock to slow. Altogether, high levels of KaiC protein can leave the cell in a state of perpetual twilight.

The researchers do not believe, however, that the Kai feedback mechanism can account for the entire 24-hour period of the clock. Even so, a single mutation in any of the Kai genes can alter, or even halt, the timing of the clock.

The kai genes do not resemble those that have been previously seen in the circadian workings of mammals and fruit flies. But Johnson and Golden believe that the basic workings that power the circadian clocks of cyanobacteria may have features in common to all clocks.

"Outlining the mechanisms in the simplest creatures known to have a circadian clock is likely to impact our thinking about how all clocks, even ours, function," said Johnson. "From cyanobacteria, we can picture how the circadian rhythms first evolved-when bacteria first learned the time of day."


Story Source:

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


Cite This Page:

National Science Foundation. "Glowing Cyanobacteria Gives Researchers New Clues To Circadian Rhythms." ScienceDaily. ScienceDaily, 7 September 1998. <www.sciencedaily.com/releases/1998/09/980907115953.htm>.
National Science Foundation. (1998, September 7). Glowing Cyanobacteria Gives Researchers New Clues To Circadian Rhythms. ScienceDaily. Retrieved November 25, 2014 from www.sciencedaily.com/releases/1998/09/980907115953.htm
National Science Foundation. "Glowing Cyanobacteria Gives Researchers New Clues To Circadian Rhythms." ScienceDaily. www.sciencedaily.com/releases/1998/09/980907115953.htm (accessed November 25, 2014).

Share This


More From ScienceDaily



More Health & Medicine News

Tuesday, November 25, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

From Popcorn To Vending Snacks: FDA Ups Calorie Count Rules

From Popcorn To Vending Snacks: FDA Ups Calorie Count Rules

Newsy (Nov. 25, 2014) — The US FDA is announcing new calorie rules on Tuesday that will require everywhere from theaters to vending machines to include calorie counts. Video provided by Newsy
Powered by NewsLook.com
Daily Serving Of Yogurt Could Reduce Risk Of Type 2 Diabetes

Daily Serving Of Yogurt Could Reduce Risk Of Type 2 Diabetes

Newsy (Nov. 25, 2014) — Need another reason to eat yogurt every day? Researchers now say it could reduce a person's risk of developing type 2 diabetes. Video provided by Newsy
Powered by NewsLook.com
Madagascar Working to Contain Plague Outbreak

Madagascar Working to Contain Plague Outbreak

AFP (Nov. 24, 2014) — Madagascar said Monday it is trying to contain an outbreak of plague -- similar to the Black Death that swept Medieval Europe -- that has killed 40 people and is spreading to the capital Antananarivo. Duration: 00:42 Video provided by AFP
Powered by NewsLook.com
Are Female Bosses More Likely To Be Depressed?

Are Female Bosses More Likely To Be Depressed?

Newsy (Nov. 24, 2014) — A new study links greater authority with increased depressive symptoms among women in the workplace. 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

 

Health & Medicine

Mind & Brain

Living & Well

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