The War between scientists and bacteria has been going on for sometime now. Sometimes it appears the scientists have an upper hand when they come up with a new anti-biotic that successfully conquers the particular strain of bacteria, and when the celebrations are still going on, different resistant strains make an appearance leaving the scientists baffled.
Now it seems that a team of scientists at the Weizmann Institute of Science have finally succeeded in designing a powerful weapon that would fight anti-resistant strains also more effectively.
The new weapon has a combination of key properties of two different types of weapons used by the innate defense systems of organisms, and is hence more effective.
The first is a 'magnetic' weapon - a natural antibiotic produced by all organisms. Because these antimicrobial peptides (AMPs) are positively charged, they are attracted to the bacteria's negatively charged surface like a magnet, where they can then exert their antibacterial effects. The second, 'detergent-like' weapon - called a lipopeptide - is produced only by bacteria and fungi, which, due to a negative charge, target fungi mainly.
This weapon contains a fatty acid chain that, like similar chains in soap that dissolve dirt and oils, breaks down the fatty membranes of the fungi.
As reported in the Proceedings of the National Academy of Sciences (PNAS), Prof. Yechiel Shai and Ph.D. students Arik Makovitzki and Dorit Avrahami of the Biological Chemistry Department have succeeded in combining the properties of AMPs with lipopeptides - resulting in a synthetic lipopeptide that has both a positive charge and the soap-like ability to dissolve oils.
By altering the length of the fatty acid chains and the sequence of positively charged amino acids, they were able to create an array of weapons. Some are active against both bacteria and fungi, while others target just one or the other.
As if this was not enough, they managed to design these new synthetic peptides (protein fragments) to contain only four amino acids, as opposed to the 12 - 50 found in their natural forms.
It is hoped that these findings will open up a whole range of potential applications. The short length of the synthetic peptide makes it attractive for drug design, as it would be both easier and economically cheaper to synthesize, less prone to resistance, and potentially modified to target a large range of bacterial and fungal infections.