Featured Research

from universities, journals, and other organizations

Silver gone astray: What concentration of silver ions disrupts biological processes in aquatic life?

Date:
February 25, 2014
Source:
EAWAG: Swiss Federal Institute of Aquatic Science and Technology
Summary:
It has long been known that, in the form of free ions, silver particles can be highly toxic to aquatic organisms. Yet to this day, there is a lack of detailed knowledge about the doses required to trigger a response and how the organisms deal with this kind of stress. To learn more about the cellular processes that occur in the cells, scientists subjected algae to a range of silver concentrations.

Silver ions disrupt cellular metabolism in the green alga Chlamydomonas reinhardtii (photo), inhibiting functions such as photosynthesis.
Credit: Image courtesy of EAWAG: Swiss Federal Institute of Aquatic Science and Technology

It has long been known that, in the form of free ions, silver particles can be highly toxic to aquatic organisms. Yet to this day, there is a lack of detailed knowledge about the doses required to trigger a response and how the organisms deal with this kind of stress. To learn more about the cellular processes that occur in the cells, scientists from the Aquatic Research Institute, Eawag, subjected algae to a range of silver concentrations.

Related Articles


In the past, silver mostly found its way into the environment in the vicinity of silver mines or via wastewater emanating from the photo industry. More recently, silver nanoparticles have become commonplace in many applications – as ingredients in cosmetics, food packaging, disinfectants, and functional clothing. Though a recent study conducted by the Swiss National Science Foundation revealed that the bulk of silver nanoparticles is retained in wastewater treatment plants, only little is known about the persistence and the impact of the residual nano-silver in the environment.

Infiltrating the energy metabolism undercover

Smitha Pillai from the Eawag Department of Environmental Toxicology and her colleagues from EPF Lausanne and ETH Zόrich studied the impact of various concentrations of waterborne silver ions on the cells of the green algae Chlamydomonas reinhardtii. Silver is chemically very similar to copper, an essential metal due to its importance in several enzymes. Because of that, silver can exploit the cells’ copper transport mechanisms and sneak into them undercover. This explains why, already after a short time, concentrations of silver in the intracellular fluid can reach up to one thousand times those in the surrounding environment.

A prompt response

Because silver damages key enzymes involved in energy metabolism, even low concentrations can cut photosynthesis and growth rates by a half in just 15 minutes. Over the same time period, the researchers also detected changes in the activity of about 1000 other genes and proteins, which they interpreted as a response to the stressor – an attempt to repair silver-induced damage. At low concentrations, the cells’ photosynthesis apparatus recovered within five hours, and recovery mechanisms were sufficient to deal with all but the highest concentrations tested.

A number of unanswered questions

At first glance, the results are reassuring because the silver concentrations that the algae are subject to in the environment are rarely as high as those applied in the lab, which allows them to recover quickly – at least externally. But the experiments also showed that even low silver concentrations have a significant effect on intracellular processes and that the algae divert their energy to repairing damage incurred. This can pose a problem when other stressors act in parallel, such as increased UV-radiation or other chemical compounds. Moreover, it remains unknown to this day whether the cells have an active mechanism to shuttle out the silver. Lacking such a mechanism, the silver could have adverse effects on higher organisms, given that algae are at the bottom of the food chain.


Story Source:

The above story is based on materials provided by EAWAG: Swiss Federal Institute of Aquatic Science and Technology. Note: Materials may be edited for content and length.


Journal Reference:

  1. S. Pillai, R. Behra, H. Nestler, M. J.- F. Suter, L. Sigg, K. Schirmer. Linking toxicity and adaptive responses across the transcriptome, proteome, and phenotype of Chlamydomonas reinhardtii exposed to silver. Proceedings of the National Academy of Sciences, 2014; DOI: 10.1073/pnas.1319388111

Cite This Page:

EAWAG: Swiss Federal Institute of Aquatic Science and Technology. "Silver gone astray: What concentration of silver ions disrupts biological processes in aquatic life?." ScienceDaily. ScienceDaily, 25 February 2014. <www.sciencedaily.com/releases/2014/02/140225101134.htm>.
EAWAG: Swiss Federal Institute of Aquatic Science and Technology. (2014, February 25). Silver gone astray: What concentration of silver ions disrupts biological processes in aquatic life?. ScienceDaily. Retrieved October 26, 2014 from www.sciencedaily.com/releases/2014/02/140225101134.htm
EAWAG: Swiss Federal Institute of Aquatic Science and Technology. "Silver gone astray: What concentration of silver ions disrupts biological processes in aquatic life?." ScienceDaily. www.sciencedaily.com/releases/2014/02/140225101134.htm (accessed October 26, 2014).

Share This



More Earth & Climate News

Sunday, October 26, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

EU Gets Climate Deal, UK PM Gets Knock

EU Gets Climate Deal, UK PM Gets Knock

Reuters - Business Video Online (Oct. 24, 2014) — EU leaders achieve a show of unity by striking a compromise deal on carbon emissions. But David Cameron's bid to push back EU budget contributions gets a slap in the face as the European Commission demands an extra 2bn euros. David Pollard reports. Video provided by Reuters
Powered by NewsLook.com
Deep Sea 'mushroom' Could Be Early Branch on Tree of Life

Deep Sea 'mushroom' Could Be Early Branch on Tree of Life

Reuters - Innovations Video Online (Oct. 24, 2014) — Miniature deep sea animals discovered off the Australian coast almost three decades ago are puzzling scientists, who say the organisms have proved impossible to categorise. Academics at the Natural History of Denmark have appealed to the world scientific community for help, saying that further information on Dendrogramma enigmatica and Dendrogramma discoides could answer key evolutionary questions. Jim Drury has more. Video provided by Reuters
Powered by NewsLook.com
Raw: Tornado Rips Roofs in Washington State

Raw: Tornado Rips Roofs in Washington State

AP (Oct. 24, 2014) — A rare tornado ripped roofs off buildings, uprooted trees and shattered windows Thursday afternoon in the southwest Washington city of Longview, but there were no reports of injuries. (Oct. 24) Video provided by AP
Powered by NewsLook.com
Fast-Moving Lava Headed For Town On Hawaii's Big Island

Fast-Moving Lava Headed For Town On Hawaii's Big Island

Newsy (Oct. 24, 2014) — Lava from the Kilauea volcano on Hawaii's Big Island has accelerated as it travels toward a town called Pahoa. 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

 

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