Protective antibiotic in breast milk

Protective antibiotic in breast milk

Graz researchers are studying protein molecule lactoferricin from breast milk
15.05.2014

If dangerous germs occur, resistance to the previously used antibiotics is becoming more and more common. Accordingly, research is working flat out to develop new strategies to continue fighting stubborn pathogens. In this context, scientists from Graz have dealt with the protein molecule lactoferricin found in breast milk as part of an EU project - and have now been able to decipher how the peptide works and how it can be enhanced. Accordingly, the current study could make an important contribution to the development of innovative antibiotics, according to the Karl-Franzens-University Graz.

Breastfeeding has many advantages If mothers breastfeed their babies, there are several advantages: vials do not have to be disinfected, milk powder does not have to be bought and mixed several times a day, and it is not necessary to bring the milk to the correct temperature for each meal. Instead, the baby can, in principle, be fed anytime and anywhere as needed. In addition to these practical aspects, breast milk has another decisive advantage over substitute food - because it contains from the start all the ingredients that are important for the development of the child in the right dose, such as carbohydrates or fat-splitting enzymes.

Protein molecules in the defense against bacteria are advantageous compared to antibiotics. Protein substances from breast milk also play an important role and are considered to be a guarantee of the natural immune defense. One of these small proteins is the “lactoferricin” peptide, which has a strong effect: “The body's own peptides - small protein molecules - have an advantage in the defense against bacteria over conventional antibiotics: they act directly and quickly on the cell membrane, the shell of the bacterium , and destroy them before resistance can form, ”explains Ass.-Prof. Dr. Dagmar Zweytick from the Institute of Molecular Biosciences at the Karl-Franzens-University Graz.

Researchers change the amino acid sequence of lactoferricin Lactoferricin occurs in natural breast milk - but in too weak a form to successfully fight serious infections. In order to increase the effectiveness, a research team from the University of Graz, in cooperation with colleagues from the universities of Ljubljana and Houston / Texas, modified the lactoferricin and was thus able to increase the natural antibacterial activity and decode the mode of action of the small molecule. As the researchers currently report in the journal “PLOS ONE”, the amino acid sequence of lactoferricin was initially changed as part of the project and a so-called “fatty acid chain” was added (acylation). Subsequent investigations showed a strong effect, because both the acylated and the non-acylated variants were now able to severely damage the cell membrane of the bacterium Escherichia coli - which was used as a model organism. “The positively charged peptides dock onto the negatively charged lipids of the bacterial cell membrane and break them open. In addition, the acylated peptides also interfere with cell division and thus bacterial reproduction. The peptide variants have already been patented internationally, ”explain the researchers at the University of Graz.

Study should help to clarify complex mechanisms of action With their work, the researchers could possibly have made an important contribution to future antibiotic research: “Overall, it can be argued that N-acylated peptides can be used in addition to killing bacteria due to the severe damage to the membrane with bacterial Lipids interact - in a way that directly or indirectly causes deficiencies in cell division. […] The study is intended to help clarify the diverse mechanisms by which antimicrobial peptides can act on bacterial membranes in order to improve peptide activity and specificity, ”said the scientists in their article. (No)

Photo credit: Rolf van Melis / pixelio.de

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