Featured Research

from universities, journals, and other organizations

What Causes Cell Defences To Crumble? Proteins In Mussels Act As Barrier To Toxic Environmental Chemicals

Date:
October 17, 2008
Source:
Helmholtz Centre For Environmental Research - UFZ
Summary:
German and American researchers have for the first time identified complete gene sequences and function of two proteins in mussels that play a key defensive role against environmental toxicants. These proteins form part of an active, physiological barrier in mussel gills that protects them against environmental toxicants.

The California mussel (Mytilus californianus) employs so called MXR proteins that antagonize the accumulation of foreign chemicals in the tissue. Environmental chemicals can act as so called chemosensitizers and block the function of those molecular pumps.
Credit: Till Luckenbach/UFZ

German and American researchers have for the first time identified complete gene sequences and function of two proteins in mussels that play a key defensive role against environmental toxicants.

Related Articles


These proteins form part of an active, physiological barrier in mussel gills that protects them against environmental toxicants, researchers from the Helmholtz Centre for Environmental Research (UFZ) and Stanford University in California report in the American Journal of Physiology - Regulatory, Integrative and Comparative Physiology.

Mussels like the California mussel (Mytilus californianus) can pump over 20 litres of water through their gills every hour. The active barrier protects the organism against harmful substances in the water. The presence of such proteins in mussel gills has been previously indicated, but it is only now that they can be accurately identified.

The function of these proteins can be inhibited by chemicals introduced into the environment by humans, e.g. galaxolide, a perfume used in cleaning products. This means that such substances open the way for other chemicals to enter cells. Even chemicals that are not regarded as toxic by conventional standards can enhance toxicity of other compounds. Little is known about the global environmental and human impacts of these 'chemosensitizers'.

Cells have mechanisms that allow them to deal with harmful substances and to survive. One such protective mechanism consists of transport proteins in the cell membrane that act as molecular 'pumps', preventing toxic compounds from accumulating in the cell. This defence mechanism against toxic chemicals is called multi-xenobiotic resistance (MXR). Substances that inhibit the MXR mechanism are called chemosensitizers.

The two recently discovered proteins are both ABC transporters. This class of membrane proteins takes its name from a shared structural element: the ATP-binding cassette (ABC). ABC transporters are one of the largest known families of proteins that occur in organisms ranging from bacteria to mammals. Similar proteins are involved in the blood-brain barrier in humans, where they prevent harmful substances from entering the sensitive nerve tissue. In mussels and other aquatic organisms this barrier does not divide different parts of the same organism, but forms a barrier towards the outside - an 'environment-tissue barrier'.

"The proteins are in the cell membrane and ensure that substances that do not belong in the cell are transported out again - like a bilge pump that pumps water out of a ship," explains Dr Till Luckenbach of the UFZ.

Possible effects of environmental chemicals on the MXR system were first described nearly 20 years ago. But it is only in recent years that scientists have begun investigating such effects in more detail.

"We want to understand the system to find out how chemicals interact with these transporters," says Luckenbach, who began researching mussels at Stanford University’s Hopkins Marine Station in California and is continuing his research using fish and mammalian cells in Leipzig at the Helmholtz Centre for Environmental Research. "So far, comparatively little is known about environment-related substances that trigger this chemical sensitization by blocking the MXR system. However, the known substances belong to very different chemical groups. This could be an indication that interactions between environmental substances and the system are widespread."

Until now, the chemicals authorisation procedure has been looking at associated risks, such as toxicity and mutagenic or carcinogenic effects. The sensitization effect of certain substances with regard to other chemicals - referred to as the chemosensitization effect by scientists - does not play a role in the current legislation.

However, Till Luckenbach and his colleagues are convinced that these substances have a major impact on the environment and that it is important to find out more about these processes.


Story Source:

The above story is based on materials provided by Helmholtz Centre For Environmental Research - UFZ. The original article was written by Tilo Arnhold. Note: Materials may be edited for content and length.


Journal References:

  1. Till Luckenbach and David Epel. ABCB- and ABCC-type transporters confer multixenobiotic resistance and form an environment-tissue barrier in bivalve gills. AJP Regulatory Integrative and Comparative Physiology, 2008; 294 (6): R1919 DOI: 10.1152/ajpregu.00563.2007
  2. Epel D., Luckenbach T., Stevenson C.N., MacManus-Spencer L.A., Hamdoun A., Smital T. Efflux transporters: newly appreciated roles in protection against pollutants. Environmental Science & Technology, 2008; 42 (11): 3914-3920 [link]

Cite This Page:

Helmholtz Centre For Environmental Research - UFZ. "What Causes Cell Defences To Crumble? Proteins In Mussels Act As Barrier To Toxic Environmental Chemicals." ScienceDaily. ScienceDaily, 17 October 2008. <www.sciencedaily.com/releases/2008/10/081009072718.htm>.
Helmholtz Centre For Environmental Research - UFZ. (2008, October 17). What Causes Cell Defences To Crumble? Proteins In Mussels Act As Barrier To Toxic Environmental Chemicals. ScienceDaily. Retrieved December 22, 2014 from www.sciencedaily.com/releases/2008/10/081009072718.htm
Helmholtz Centre For Environmental Research - UFZ. "What Causes Cell Defences To Crumble? Proteins In Mussels Act As Barrier To Toxic Environmental Chemicals." ScienceDaily. www.sciencedaily.com/releases/2008/10/081009072718.htm (accessed December 22, 2014).

Share This


More From ScienceDaily



More Plants & Animals News

Monday, December 22, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Christmas Kissing Good for Health

Christmas Kissing Good for Health

Reuters - Innovations Video Online (Dec. 22, 2014) Scientists in Amsterdam say couples transfer tens of millions of microbes when they kiss, encouraging healthy exposure to bacteria. Suzannah Butcher reports. Video provided by Reuters
Powered by NewsLook.com
Brain-Dwelling Tapeworm Reveals Genetic Secrets

Brain-Dwelling Tapeworm Reveals Genetic Secrets

Reuters - Innovations Video Online (Dec. 22, 2014) Cambridge scientists have unravelled the genetic code of a rare tapeworm that lived inside a patient's brain for at least four year. Researchers hope it will present new opportunities to diagnose and treat this invasive parasite. Matthew Stock reports. Video provided by Reuters
Powered by NewsLook.com
Earthworms Provide Cancer-Fighting Bacteria

Earthworms Provide Cancer-Fighting Bacteria

Reuters - Innovations Video Online (Dec. 21, 2014) Polish scientists isolate bacteria from earthworm intestines which they say may be used in antibiotics and cancer treatments. Suzannah Butcher reports. Video provided by Reuters
Powered by NewsLook.com
Existing Chemical Compounds Could Revive Failing Antibiotics, Says Danish Scientist

Existing Chemical Compounds Could Revive Failing Antibiotics, Says Danish Scientist

Reuters - Innovations Video Online (Dec. 21, 2014) A team of scientists led by Danish chemist Jorn Christensen says they have isolated two chemical compounds within an existing antipsychotic medication that could be used to help a range of failing antibiotics work against killer bacterial infections, such as Tuberculosis. Jim Drury went to meet him. 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