PRESS-NEWS.org - Press Release Distribution
PRESS RELEASES DISTRIBUTION

ABC transporters enable leaf beetle larvae to accumulate defensive precursors when feeding

Similar membrane proteins play a crucial role in the transport of toxic substances out of the cell

2013-12-09
(Press-News.org) Contact information: Dr. Antje Burse
aburse@ice.mpg.de
49-364-157-1265
Max Planck Institute for Chemical Ecology
ABC transporters enable leaf beetle larvae to accumulate defensive precursors when feeding Similar membrane proteins play a crucial role in the transport of toxic substances out of the cell

This news release is available in German.

Scientists at the Max Planck Institute for Chemical Ecology in Jena, Germany, have discovered the decisive biological stimulator for the accumulation of defensive substances in leaf beetle larvae used by the insects to fend off predators: ABC transport proteins, which are found in large quantities in glandular cells of the larvae. The poplar leaf beetle Chrysomela populi is able to transport salicin, which is found in its leafy diet and is absorbed in its midgut, via several cell membranes into its defensive glands, where the substance is converted into the defensive compound salicyl aldehyde. The research results not only shed light on the molecular evolution of the defensive system in leaf beetle larvae but also help to elucidate cell biological processes of sequestration in animal tissues. (eLIFE, December 3, 2013, DOI: 10.7554/eLife.01096)

Food chains and how to escape them

Leaf beetle larvae are part of food chains. They are attacked by predatory insects and parasites, such as hover flies and bugs. To protect themselves, some leaf beetle larvae have developed sophisticated mechanisms. Upon being disturbed, they emit a deterrent from their defensive glands as little droplets on their back. The defensive substances in the secretion are synthesized by the larvae from chemical precursors ingested when the larvae feed on leaves; instead of synthesizing these substances on their own, they save energy. In the case of the poplar leaf beetle, the chemical precursor is salicin, which is present in the leaf tissues of poplars and willows. A sophisticated transport network carries the precursors from the gut into the defensive glands. Only two more enzymatic steps are necessary in order to accumulate the defensive substance salicyl aldehyde in very high concentrations.

But how exactly does the transport work across the membranes of respective tissues? At which stage of the sequestration process does the selection take place? Which nutrients remain in the gut? Which are transported into the defensive glands and the toxic reservoir of the beetle larvae?

VIDEO: This is a 3D representation of CpMRP localization within a secretory cell of a poplar leaf beetle: CpMPR (green) is present in the entire cell and forms a huge network.
Click here for more information.

CpMRP: A gene highly expressed in the glandular cells

Anja Strauß, who wrote her PhD thesis in the Department of Bioorganic Chemistry at the Max Planck Institute for Chemical Ecology, unraveled the mystery of this mechanism. She studied the gene transcripts in the secretory cells of the poplar leaf beetle Chrysomela populi and found a gene which is 7000 times more expressed in the glandular tissue than in the gut tissue. Gene sequence analysis revealed that the scientists had cloned the gene for a so-called ABC transport protein. Such transport proteins are widespread and occur in almost all organisms, from bacteria to mammals. They also mediate multi-drug resistance, i.e. the resistance to pharmaceutically active compounds, transporting toxic substances potentially dangerous for the cell either away from the cell or into the tiniest cell organelles where they are rendered harmless. However, what role do ABC transporters play in leaf beetle larvae and how are they involved in the typical mechanisms of precursor accumulation in these insects? This was the crucial question Wilhelm Boland, director at the institute, asked.

RNAi confirms key role of ABC transporter

Experiments clearly demonstrated that CpMRP − as the scientists named the transporter − is located in very large amounts in the membranes of small bubbles, the storage vesicles within glandular cells. As soon as the precursors of defensive compounds (here: salicin) are ingested and reach the cells, they immediately accumulate in the cells' abundant vesicles with the help of ATP, the cell's energy currency. This is where the name ABC transporter comes from: ATP-binding cassette transporter. The vesicles migrate within glandular cells in the direction of the reservoir, where they unite with the membrane barrier of the large reservoir and distribute their contents. The defensive compound salicyl aldehyde is then produced by the salicin precursor. In case of danger, the repellent is secreted from the tips of the glandular tubercles as the larvae assume a threatening posture.

CpMRP functions as a pacemaker in this process: Thanks to its high transport capacities, CpMRP generates a decline in the concentration of salicin in the glandular tissue. As a consequence, there is a continuous and selective flow of salicin molecules via yet unknown transport proteins from the larvae's bodily fluid. Should the CpMRP gene be switched off by means of RNAi, leaf beetle larvae without the transporter are no longer able to emit defensive compounds. This is how the key role of the transporter was demonstrated.

"It is fascinating that ABC transporters form a huge network within the glandular cells of the leaf beetle larvae which efficiently absorbs the toxins and traps them in storage vesicles," says Anja Strauß. However: "The process we observed in those insects is not a detoxification process, but rather a well-directed accumulation of toxin precursors ingested by the larvae when they feed on leaves. These precursors are used economically to fend off predators."

The identification of the CpMRP transporter not only sheds new light on the molecular evolution of the defensive system in leaf beetle larvae, it also demonstrates another important step in the elucidation of the biological basis of cellular sequestration and storage processes in animal tissues.



INFORMATION:



[JWK/AO]

Original Publication:

Strauß, A., Peters, S., Boland, W., Burse, A. (2013). ABC transporter functions as a pacemaker for the sequestration of plant glucosides in leaf beetles. eLIFE, December 3, 2013, DOI: 10.7554/eLife.01096 http://dx.doi.org/10.7554/eLife.01096

Further Information:

Dr. Antje Burse, +49 3641 57-1265, aburse@ice.mpg.de

Prof. Dr. Wilhelm Boland, +49 3641 57-1200, boland@ice.mpg.de

Contact and picture requests:

Angela Overmeyer M.A., MPI for Chemical Ecology, Hans-Knöll-Str. 8, 07743 Jena, + 49 3641 57-2110, overmeyer@ice.mpg.de

Download of high resolution pictures on http://www.ice.mpg.de/ext/735.html



ELSE PRESS RELEASES FROM THIS DATE:

Recycled plastic proves effective in killing drug-resistant fungi

2013-12-09
Recycled plastic proves effective in killing drug-resistant fungi IBN and IBM discover new medical application for converted PET bottles Singapore, December 9, 2013 – Researchers at Singapore's Institute of Bioengineering ...

Reproductive Health Matters announces publication of its latest themed issue: New development paradigm

2013-12-09
Reproductive Health Matters announces publication of its latest themed issue: New development paradigm London, December 9, 2013 – The world is still underfunding health: so what kind of new development paradigm will succeed in ensuring comprehensive and equitable ...

Life and work -- 1 and the same?

2013-12-09
Life and work -- 1 and the same? London, Los Angeles CA (09 December, 2013). Flexible workplaces may seem attractive when considering work-life balance but new research being published shows it's not unusual for firms to cash-in, profiting from our "free" time ...

Solar cell degradation observed directly for the first time

2013-12-09
Solar cell degradation observed directly for the first time X-ray examination shows structural changes in 'plastics' solar cells This news release is available in German. With the help of DESY's X-ray light source PETRA III, researchers of ...

Aging out of bounds

2013-12-09
Aging out of bounds New demographic data show how diversely different species age -- biologists cannot explain why This news release is available in German. Despite aging being one the hottest topic in the media recently, scientists have ...

Polymers can be semimetals

2013-12-09
Polymers can be semimetals Traditional plastics, or polymers, are electrical insulators. In the seventies a new class of polymers that conduct electricity like semiconductors and metals was discovered by Alan J.Heeger, Alan G. MacDiarmid and Hideki Shirakawa. This ...

Millions of hidden share trades to be revealed

2013-12-09
Millions of hidden share trades to be revealed Millions of previously hidden US stock trades will be revealed for the first time on Monday December 9 thanks to research from a team of academics. Previously odd lots, which are trades of less than 100 shares, ...

New insights into the immune system of the gastrointestinal tract

2013-12-09
New insights into the immune system of the gastrointestinal tract An international team of scientists supported by the Helmholtz Zentrum München has now discovered how this complex ...

Researchers develop system for assessing how effective species are at pollinating crops

2013-12-09
Researchers develop system for assessing how effective species are at pollinating crops From tomatoes to pumpkins, most fruit and vegetable crops rely on pollination by bees and other insect species – and the future of many of those species is uncertain. ...

Keep on exercising, researchers advise older breast cancer survivors

2013-12-09
Keep on exercising, researchers advise older breast cancer survivors 1 year of exercise can ensure steady maintenance of bone density to help prevent fractures To build and maintain muscle strength, it is best for older breast cancer survivors to follow an ongoing exercise ...

LAST 30 PRESS RELEASES:

Public take the lead in discovery of new exploding star

What are they vaping? Study reveals alarming surge in adolescent vaping of THC, CBD, and synthetic cannabinoids

ECMWF - delivering forecasts over 10 times faster and cutting energy usage by 1000

Brazilian neuroscientist reveals how viral infections transform the brain through microscopic detective work

Turning social fragmentation into action through discovering relatedness

Cheese may really be giving you nightmares, scientists find

Study reveals most common medical emergencies in schools

Breathable yet protective: Next-gen medical textiles with micro/nano networks

Frequency-engineered MXene supercapacitors enable efficient pulse charging in TENG–SC hybrid systems

Developed an AI-based classification system for facial pigmented lesions

Achieving 20% efficiency in halogen-free organic solar cells via isomeric additive-mediated sequential processing

New book Terraglossia reclaims language, Country and culture

The most effective diabetes drugs don't reach enough patients yet

Breast cancer risk in younger women may be influenced by hormone therapy

Strategies for staying smoke-free after rehab

Commentary questions the potential benefit of levothyroxine treatment of mild hypothyroidism during pregnancy

Study projects over 14 million preventable deaths by 2030 if USAID defunding continues

New study reveals 33% gap in transplant access for UK’s poorest children

Dysregulated epigenetic memory in early embryos offers new clues to the inheritance of polycystic ovary syndrome (PCOS)

IVF and IUI pregnancy rates remain stable across Europe, despite an increasing uptake of single embryo transfer

It takes a village: Chimpanzee babies do better when their moms have social connections

From lab to market: how renewable polymers could transform medicine

Striking increase in obesity observed among youth between 2011 and 2023

No evidence that medications trigger microscopic colitis in older adults

NYUAD researchers find link between brain growth and mental health disorders

Aging-related inflammation is not universal across human populations, new study finds

University of Oregon to create national children’s mental health center with $11 million federal grant

Rare achievement: UTA undergrad publishes research

Fact or fiction? The ADHD info dilemma

Genetic ancestry linked to risk of severe dengue

[Press-News.org] ABC transporters enable leaf beetle larvae to accumulate defensive precursors when feeding
Similar membrane proteins play a crucial role in the transport of toxic substances out of the cell