Featured Research

from universities, journals, and other organizations

Three-dimensional model of bacterium created

Date:
August 15, 2013
Source:
Heidelberg, Universität
Summary:
New methods of electron microscopy have decoded the structure of Gemmata obscuriglobus.

3D reconstruction of bacteria with a complex endomembrane system.
Credit: Copyright Heidelberg, Universität

Certain bacteria can build such complex membrane structures that, in terms of complexity and dynamics, look like eukaryotes, i.e., organisms with a distinct membrane-bound nucleus. Scientists from Heidelberg University and the European Molecular Biology Laboratory (EMBL) made this discovery employing new methods in electron microscopy. The research team succeeded in building a three-dimensional model of the Gemmata obscuriglobus bacterium, including the structure of its membrane system. Their studies demonstrated, however, that the G. obscuriglobus does not have a "true" nucleus. Despite this outlier characteristic, it remains classified as a bacterium and thus a so-called prokaryote.

The results of their research were published in PLoS Biology.

"Since the beginning of microscopy, cells of living organisms have been classified into one of two categories," explains Dr. Damien Devos, a researcher at the Centre for Organismal Studies (COS) at Heidelberg University. Eukaryotes "pack" their genetic material, their DNA, in an area enclosed in a membrane, the nucleus. Prokaryotes, however, which also include bacteria, do not have that type of cell nucleus. Several years ago, analyses using new techniques of two-dimensional imaging had suggested that the genetic material of G. obscuriglobus was surrounded by a double membrane -- this and other unique characteristics of membrane structure called into question the differentiation between prokaryotes and eukaryotes.

"The possibility that a bacterium could have a structure similar to a cell nucleus threatened to unhinge one of the central assumptions of biology on which countless other analyses and interpretations were based," explains Damien Devos. To study the unique features of the membrane structure in the G. obscuriglobus more closely, the Heidelberg researchers divided the bacterium into thin slices and examined them using an electron microscope. The slices were used to detect the membranes, track their course throughout the entire bacterium and reconstruct their organisation on the computer. This created a virtual model of G. obscuriglobus, which enabled the researchers to visualise the membrane organisation in three-dimensional space and analyse how the membranes were structured within the cell.

The studies demonstrated that the membranes within the G. obscuriglobus are only one part of the interior membrane that is present in all bacteria and that surrounds the cytoplasm. "G. obscuriglobus also evidenced additional characteristics that are found in other bacteria," explains Damien Devos. According to the researcher, these results disprove the assumption of the existence of a bacterial cell nucleus. "The cell structure and the membranes of the Gemmata obscuriglobus are simply more complex than in 'classic' bacteria.Therefore, G. obscuriglobus does not constitute a new, separate group of organisms, and it cannot be classified a eukaryote," says Dr. Devos, who collaborated with Rachel Santarella-Mellwig of the European Molecular Biology Laboratory.


Story Source:

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


Journal Reference:

  1. Rachel Santarella-Mellwig, Sabine Pruggnaller, Norbert Roos, Iain W. Mattaj, Damien P. Devos. Three-Dimensional Reconstruction of Bacteria with a Complex Endomembrane System. PLoS Biology, 2013; 11 (5): e1001565 DOI: 10.1371/journal.pbio.1001565

Cite This Page:

Heidelberg, Universität. "Three-dimensional model of bacterium created." ScienceDaily. ScienceDaily, 15 August 2013. <www.sciencedaily.com/releases/2013/08/130815113532.htm>.
Heidelberg, Universität. (2013, August 15). Three-dimensional model of bacterium created. ScienceDaily. Retrieved September 19, 2014 from www.sciencedaily.com/releases/2013/08/130815113532.htm
Heidelberg, Universität. "Three-dimensional model of bacterium created." ScienceDaily. www.sciencedaily.com/releases/2013/08/130815113532.htm (accessed September 19, 2014).

Share This



More Plants & Animals News

Friday, September 19, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Raw: Elephant Undergoes Surgery in Tbilisi Zoo

Raw: Elephant Undergoes Surgery in Tbilisi Zoo

AP (Sep. 18, 2014) — Grand the elephant has successfully undergone surgery to remove a portion of infected tusk at Tbilisi Zoo in Georgia. British veterinary surgeons used an electric drill to extract the infected piece. (Sept. 18) Video provided by AP
Powered by NewsLook.com
Chimp Violence Study Renews Debate On Why They Kill

Chimp Violence Study Renews Debate On Why They Kill

Newsy (Sep. 17, 2014) — The study weighs in on a debate over whether chimps are naturally violent or become that way due to human interference in the environment. Video provided by Newsy
Powered by NewsLook.com
Some Tobacco Farmers Thrive Amid Challenges

Some Tobacco Farmers Thrive Amid Challenges

AP (Sep. 16, 2014) — The South's tobacco country is surviving, and even thriving in some cases, as demand overseas keeps growers in the fields of one of America's oldest cash crops. (Sept. 16) Video provided by AP
Powered by NewsLook.com
Scientists Given Rare Glimpse of 350-Kilo Colossal Squid

Scientists Given Rare Glimpse of 350-Kilo Colossal Squid

AFP (Sep. 16, 2014) — Scientists say a female colossal squid weighing an estimated 350 kilograms (770 lbs) and thought to be only the second intact specimen ever found was carrying eggs when discovered in the Antarctic. Duration: 00:47 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