Featured Research

from universities, journals, and other organizations

Previously unknown ocean bacteria lead scientists to entirely new theories

Date:
September 19, 2011
Source:
Uppsala University
Summary:
Earth's most successful bacteria are found in the oceans and belong to the group SAR11. Researchers have now provide an explanation for their success and at the same time call into question generally accepted theories about these bacteria. In their analysis they have also identified a rare and hitherto unknown relative of mitochondria, the power stations inside cells.

Earth's most successful bacteria are found in the oceans and belong to the group SAR11. In a new study, researchers from Uppsala University provide an explanation for their success and at the same time call into question generally accepted theories about these bacteria. In their analysis they have also identified a rare and hitherto unknown relative of mitochondria, the power stations inside cells.

The findings were published in two articles in the journals Molecular Biology and Evolution and PLoS ONE in the last week.

"The huge amounts of DNA information now being produced from the oceans gives us a glimpse of a world that could never be studied before. It's incredibly fascinating to look for answers to the fundamental questions of life in these data," says Siv Andersson, professor of molecular evolution and lead author of the studies.

Bacteria belonging to the group SAR11 make up 30-40 percent of all bacteria cells in the oceans and therefore play a considerable role in global carbon cycles. Nowhere else are these bacteria so common. The open seas are poor in nutrients, and SAR11 bacteria have an extremely small cell volume in order to maximize the concentration of nutrients in the cells. Their genes are small, consisting of fewer than 1.5 million building blocks.

According to previous research they are related to an equally specialized group of bacteria that includes the typhus bacterium. These bacteria also have small genes, but they are adapted to humans, animals, and insects. However, the advanced analyses of genetic relationships performed by the Uppsala researchers contradict these findings, indicating instead that SAR11 bacteria evolved from ocean- and earth-dwelling bacteria with genes that are three to ten times as large. But unlike their relatives, SAR11 bacteria lack genes that are thought to be important in repairing damage to DNA. This might also explain why they have been so successful.

"The loss of genes means that the bacteria can more readily exchange genes with each other, and beneficial genes can then spread rapidly in the oceans as an adaptation to changes in nutrient content, temperature, and UV radiation," says Johan Viklund, a doctoral candidate at the Department of Molecular Evolution.

From data from currently ongoing major international surveys of DNA from all the bacteria in the oceans, the Uppsala scientists have also found DNA sequences for proteins that participate in cell respiration, when sugar is broken down into carbon dioxide and water. By comparing these with comparable proteins for cell respiration in humans, animals, and insects in so-called mitochondria, the researchers managed to identify a rare, previously unknown group of bacteria.

"They are very similar to mitochondria. Our findings thus indicate that the origin of mitochondria might be the oceans, but that they are not related to the SAR11 group as was previously thought," says Thijs Ettema, a postdoctoral fellow with the team.


Story Source:

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


Journal References:

  1. J. Viklund, T. J. G. Ettema, S. G. E. Andersson. Independent Genome Reduction and Phylogenetic Reclassification of the Oceanic SAR11 Clade. Molecular Biology and Evolution, 2011; DOI: 10.1093/molbev/msr203
  2. Björn Brindefalk, Thijs J. G. Ettema, Johan Viklund, Mikael Thollesson, Siv G. E. Andersson. A Phylometagenomic Exploration of Oceanic Alphaproteobacteria Reveals Mitochondrial Relatives Unrelated to the SAR11 Clade. PLoS ONE, 2011; 6 (9): e24457 DOI: 10.1371/journal.pone.0024457

Cite This Page:

Uppsala University. "Previously unknown ocean bacteria lead scientists to entirely new theories." ScienceDaily. ScienceDaily, 19 September 2011. <www.sciencedaily.com/releases/2011/09/110916114110.htm>.
Uppsala University. (2011, September 19). Previously unknown ocean bacteria lead scientists to entirely new theories. ScienceDaily. Retrieved October 1, 2014 from www.sciencedaily.com/releases/2011/09/110916114110.htm
Uppsala University. "Previously unknown ocean bacteria lead scientists to entirely new theories." ScienceDaily. www.sciencedaily.com/releases/2011/09/110916114110.htm (accessed October 1, 2014).

Share This



More Plants & Animals News

Wednesday, October 1, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Earth Has Lost Half Its Vertebrate Wildlife Since 1970: WWF

Earth Has Lost Half Its Vertebrate Wildlife Since 1970: WWF

Newsy (Sep. 30, 2014) — A new study published by the World Wide Fund for Nature found that more than half of the world's wildlife population has declined since 1970. Video provided by Newsy
Powered by NewsLook.com
Dolphins Might Use Earth's Magnetic Field As A GPS

Dolphins Might Use Earth's Magnetic Field As A GPS

Newsy (Sep. 30, 2014) — A study released Monday suggests dolphins might be able to sense the Earth's magnetic field and possibly use it as a means of navigation. Video provided by Newsy
Powered by NewsLook.com
How To Battle Stink Bug Season

How To Battle Stink Bug Season

Newsy (Sep. 30, 2014) — Homeowners in 33 states grapple with stink bugs moving indoors at this time of year. Here are a few tips to avoid stink bug infestations. Video provided by Newsy
Powered by NewsLook.com
California University Designs Sustainable Winery

California University Designs Sustainable Winery

Reuters - US Online Video (Sep. 27, 2014) — Amid California's worst drought in decades, scientists at UC Davis design a sustainable winery that includes a water recycling system. Vanessa Johnston reports. Video provided by Reuters
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