Featured Research

from universities, journals, and other organizations

Bacteria divide like clockwork: Cell division in cyanobacteria controlled by same kind of circadian rhythms that govern human sleep

Date:
April 8, 2010
Source:
Massachusetts Institute of Technology
Summary:
Scientists have shown how cell division in a type of bacteria known as cyanobacteria is controlled by the same kind of circadian rhythms that govern human sleep patterns. Previous studies have shown that even though cyanobacteria do not "sleep" in the same way that humans do, they cycle through active and resting periods on a 24-hour schedule. Cyanobacteria depend on sunlight for photosynthesis, so they are most active during the day.

Physics Professor Alexander van Oudenaarden, left, works in his lab with physics graduate student Bernardo Pando.
Credit: Photo by Patrick Gillooly

A team of researchers at MIT and the University of California at San Diego has shown how cell division in a type of bacteria known as cyanobacteria is controlled by the same kind of circadian rhythms that govern human sleep patterns.

Previous studies have shown that even though cyanobacteria do not "sleep" in the same way that humans do, they cycle through active and resting periods on a 24-hour schedule. Cyanobacteria depend on sunlight for photosynthesis, so they are most active during the day.

The researchers demonstrate, for the first time, how the circadian clock regulates the bacteria's rate of cell division (their method of reproduction) in single cells. "These cells have to keep dividing, and the circadian oscillator regulates when they divide," says Bernardo Pando, an MIT graduate student in physics and one of the lead authors of a paper describing the findings in the March 18 online edition of Science.

In multicellular animals, including humans, cell division is critical for renewal and repair, while out-of-control cell division leads to cancer, so "understanding how cells are dividing is really of fundamental importance," says Susan Golden, professor of molecular biology at the University of California at San Diego and an author of the paper.

Cyanobacteria maintain their circadian rhythms even when isolated from the naturally occurring daily light-dark cycles of the sun, just as humans do. The researchers found that under conditions of moderate constant light, the cyanobacteria undergo cell division about once per day, and the divisions take place mostly at the midpoint of the 24-hour cycle

To figure out how the cell division cycle is coupled to the circadian clock, the researchers sped up the cell cycle by boosting the intensity of light, enabling the cells to photosynthesize more, which increases the amount of energy available to them. The cells did start to divide more frequently, but in a pattern still linked to the circadian clock -- they divided once a quarter of the way into the cycle, and again three-quarters into the cycle.

The team also showed that the cyanobacteria enter a resting phase about 19 hours into the circadian cycle, after which they will not divide until the next cycle begins.

How they did it: The researchers tracked single cells over a weeklong period. Proteins that govern the circadian clock were tagged with yellow fluorescent protein, so each cell's position in the 24-hour cycle could be pinpointed. Cells were also photographed every 40 minutes, so researchers could see when they divided.

This is the first time researchers have studied how cell cycle and circadian rhythms are coupled in individual bacterial cells. "You can only do this by looking at single cells," says Alexander van Oudenaarden, MIT professor of biophysics and senior author of the paper.

The same experimental setup could be used to study the relationship between circadian clocks and any other cell function that oscillates periodically. Yeast and mammalian cells are logical targets for such studies, says van Oudenaarden. Golden is planning further studies into how the circadian clock and proteins that control cell division in cyanobacteria are linked.

Funding was provided by the National Science Foundation, National Institutes of Health.


Story Source:

The above story is based on materials provided by Massachusetts Institute of Technology. The original article was written by Anne Trafton, MIT News Office. Note: Materials may be edited for content and length.


Journal Reference:

  1. Qiong Yang, Bernando Pando, Guogang Dong, Susan Golden, Alexander van Oudenaarden. Circadian Gating of the Cell Cycle Revealed in Single Cyanobacterial Cells. Science, March 19, 2010 DOI: 10.1126/science.1181759

Cite This Page:

Massachusetts Institute of Technology. "Bacteria divide like clockwork: Cell division in cyanobacteria controlled by same kind of circadian rhythms that govern human sleep." ScienceDaily. ScienceDaily, 8 April 2010. <www.sciencedaily.com/releases/2010/03/100318141544.htm>.
Massachusetts Institute of Technology. (2010, April 8). Bacteria divide like clockwork: Cell division in cyanobacteria controlled by same kind of circadian rhythms that govern human sleep. ScienceDaily. Retrieved April 21, 2014 from www.sciencedaily.com/releases/2010/03/100318141544.htm
Massachusetts Institute of Technology. "Bacteria divide like clockwork: Cell division in cyanobacteria controlled by same kind of circadian rhythms that govern human sleep." ScienceDaily. www.sciencedaily.com/releases/2010/03/100318141544.htm (accessed April 21, 2014).

Share This



More Plants & Animals News

Monday, April 21, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Breakfast Foods Are Getting Pricier

Breakfast Foods Are Getting Pricier

AP (Apr. 21, 2014) — Breakfast is now being served with a side of sticker shock. The cost of morning staples like bacon, coffee and orange juice is on the rise because of global supply problems. (April 21) Video provided by AP
Powered by NewsLook.com
Mich. Boy Unearths 10,000-Year-Old Mastodon Tooth

Mich. Boy Unearths 10,000-Year-Old Mastodon Tooth

Newsy (Apr. 20, 2014) — A 9-year-old Michigan boy was exploring a creek when he came across a 10,000-year-old tooth from a prehistoric mastodon. Video provided by Newsy
Powered by NewsLook.com
Vermont Goat Meat Gives Refugees Taste of Home

Vermont Goat Meat Gives Refugees Taste of Home

AP (Apr. 18, 2014) — Dairy farmers and ethnic groups in Vermont are both benefiting from a unique collaborative effort that's feeding a growing need for fresh and affordable goat meat. (April 18) Video provided by AP
Powered by NewsLook.com
Man Claims He Found Loch Ness Monster With... Apple Maps?

Man Claims He Found Loch Ness Monster With... Apple Maps?

Newsy (Apr. 18, 2014) — Andy Dixon showed the Daily Mail a screenshot of what he believes to be the mythical beast swimming just below the lake's surface. 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:
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