Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Insect Antibiotics - Resistance is Futile!

07.02.2003


Insect Antibiotic, Cecropin A, Bypasses Outer Defenses to Kill Bacteria From The Inside

For antibiotics, the best way to beat bacterial defenses may be to avoid them altogether. Researchers at University of Pennsylvania School of Medicine have discovered that Cecropin A, a member of a family of antibiotic proteins produced by insects, may kill bacteria and avoid resistance by entering bacterial cells and taking control of their genetic machinery.

While most antibiotics kill bacteria by attacking critical enzyme systems, Cecropin A somehow slips inside the bacteria and turns specific genes on and off. The findings challenge conventional thinking on how these antibiotics function, and may aid in turning antimicrobial peptides like Cecropin A into therapeutic agents.



"For decades, researchers have studied Cecropin A and focused on its obvious effects against bacterial cell walls and membranes. These antibiotics certainly do disrupt outer structures of the bacterial cell, but there’s much more to the story," said Paul H. Axelsen, M.D., an associate professor in the Department of Pharmacology and Division of Infectious Diseases at Penn. "Before the bacterial cell dies, Cecropin A enters the cell and alters the way its genes are regulated. It’s like sneaking over the castle wall and opening the gates from the inside. We need to understand this mechanism of action because it may explain why bacteria are unable to develop resistance to this family of antibiotics."

Axelsen’s findings were described in the January issue of the Antimicrobial Agents and Chemotherapy, a publication of the American Society for Microbiology. In their study, Axelsen and his colleagues treated E. coli with small doses of Cecropin A - not enough to kill the bacteria, but enough to see what genes are affected when bacteria are exposed to the antibiotic. They found that transcript levels for 26 genes are affected, 11 of which code for proteins whose functions are unknown. Even more surprising for the researchers, the genes are not the same as the ones affected when bacteria experience nutritional, thermal, osmotic, or oxidative stress.

"It is a whole different mechanism by which to kill bacteria, and one that we still have yet to completely figure out," said Axelsen. "How Cecropin A turns these genes on and, indeed, how it gets inside E. coli in the first place, is still something of a mystery."

Despite years of research, there remains much to know about the antibiotics produced by insects. Cecropin A was discovered in the Cecropia moth, also known as the silkworm moth, the largest moth in North America. Since insects do not have an immune system as humans do, they rely on polypeptide antibiotics like Cecropin A to fight off infections. These proteins are highly selective - they readily kill bacteria, but are harmless to human and other animal cells. Moreover, bacteria that are susceptible initially stay susceptible - researchers have not seen bacteria develop resistance to their action. For this reason, these antibiotics offer a potentially invaluable model for new therapeutic agents.

"We’re engaged in an arms race against infectious bacteria. With each new antibiotic, bacteria have found a way to evolve resistance - primarily by slightly altering cellular enzymes," said Axelsen. "Bacteria may be unable to alter their genetic machinery, and this may explain why strains of bacteria resistant to Cecropin A do not arise."

Funding for this research was supported by grants from the National Institutes of Health and the American Heart Association, and from Affymetrix’s generous donation of E. coli GeneChip Microarrays.

Greg Lester | University of Pennsylvania Medic
Further information:
http://health.upenn.edu/News/News_Releases/feb03/Insects.html

More articles from Life Sciences:

nachricht Discovery of a Key Regulatory Gene in Cardiac Valve Formation
24.05.2017 | Universität Basel

nachricht Carcinogenic soot particles from GDI engines
24.05.2017 | Empa - Eidgenössische Materialprüfungs- und Forschungsanstalt

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: A quantum walk of photons

Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.

The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....

Im Focus: Turmoil in sluggish electrons’ existence

An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.

We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...

Im Focus: Wafer-thin Magnetic Materials Developed for Future Quantum Technologies

Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.

Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...

Im Focus: World's thinnest hologram paves path to new 3-D world

Nano-hologram paves way for integration of 3-D holography into everyday electronics

An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...

Im Focus: Using graphene to create quantum bits

In the race to produce a quantum computer, a number of projects are seeking a way to create quantum bits -- or qubits -- that are stable, meaning they are not much affected by changes in their environment. This normally needs highly nonlinear non-dissipative elements capable of functioning at very low temperatures.

In pursuit of this goal, researchers at EPFL's Laboratory of Photonics and Quantum Measurements LPQM (STI/SB), have investigated a nonlinear graphene-based...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Marine Conservation: IASS Contributes to UN Ocean Conference in New York on 5-9 June

24.05.2017 | Event News

AWK Aachen Machine Tool Colloquium 2017: Internet of Production for Agile Enterprises

23.05.2017 | Event News

Dortmund MST Conference presents Individualized Healthcare Solutions with micro and nanotechnology

22.05.2017 | Event News

 
Latest News

Physicists discover mechanism behind granular capillary effect

24.05.2017 | Physics and Astronomy

Measured for the first time: Direction of light waves changed by quantum effect

24.05.2017 | Physics and Astronomy

Marine Conservation: IASS Contributes to UN Ocean Conference in New York on 5-9 June

24.05.2017 | Event News

VideoLinks
B2B-VideoLinks
More VideoLinks >>>