Navigation Links
What causes cell defenses to crumble?
Date:10/9/2008

This release is available in German.

Pacific Grove (CA)/Leipzig. 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, researchers from the Helmholtz Centre for Environmental Research (UFZ) in Germany 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 (Germany) 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.


'/>"/>

Contact: Tilo Arnhold
presse@ufz.de
49-341-235-1635
Helmholtz Association of German Research Centres
Source:Eurekalert  

Related biology news :

1. Hidden interactions between predators and prey: evolution causes cryptic dynamics in ecology
2. Grubs passion for plastic causes water loss
3. St. Jude identifies the specific cell that causes eye cancer, disproving long-held theory
4. Influenza vaccine causes weaker immune response for children of rural Gabon than in semi-urban areas
5. First-ever study: lack of critical lubricant causes wear in joints
6. NIH selects LIAI for major study on allergy molecular causes and possible treatments
7. USC researchers explore genetic causes for male infertility
8. What are the causes and consequences of childhood obesity?
9. Scientists discover how cigarette smoke causes cancer: Study points to new treatments, safer tobacco
10. Kids with autism may have gene that causes muscle weakness
11. Geisinger study: Inflammatory disease causes blindness
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
What causes cell defenses to crumble?
(Date:5/16/2016)... --  EyeLock LLC , a market leader of iris-based ... IoT Center of Excellence in Austin, Texas ... embedded iris biometric applications. EyeLock,s iris authentication ... with unmatched biometric accuracy, making it the most proven ... platform uses video technology to deliver a fast and ...
(Date:4/28/2016)... First quarter 2016:   , ... the first quarter of 2015 The gross margin was ... 18.8) and the operating margin was 40% (-13) Earnings ... flow from operations was SEK 249.9 M (21.2) , ... SEK 7,000-8,500 M. The operating margin for 2016 is ...
(Date:4/15/2016)... , April 15, 2016 ... "Global Gait Biometrics Market 2016-2020,"  report to their ... ) , ,The global gait biometrics market ... 13.98% during the period 2016-2020. Gait ... which can be used to compute factors that ...
Breaking Biology News(10 mins):
(Date:6/27/2016)... , June 27, 2016  Sequenom, Inc. (NASDAQ: ... enabling healthier lives through the development of innovative products ... the United States denied its ... the claims of Sequenom,s U.S. Patent No. 6,258,540 (",540 ... criteria established by the Supreme Court,s Mayo Collaborative Services ...
(Date:6/27/2016)... -- Liquid Biotech USA , Inc. ... Research Agreement with The University of Pennsylvania ("PENN") ... patients.  The funding will be used to assess ... outcomes in cancer patients undergoing a variety of ... to support the design of a therapeutic, decision-making ...
(Date:6/24/2016)... ... 24, 2016 , ... Researchers at the Universita Politecnica delle Marche in Ancona ... or pleural mesothelioma. Their findings are the subject of a new article on the ... are signposts in the blood, lung fluid or tissue of mesothelioma patients that can ...
(Date:6/23/2016)... Md. , June 23, 2016 A person ... from the crime scene to track the criminal down. ... the U.S. Food and Drug Administration (FDA) uses DNA evidence ... Sound far-fetched? It,s not. The FDA ... sequencing to support investigations of foodborne illnesses. Put as simply ...
Breaking Biology Technology: