A recent news on The Scientist highlights the presence of antibiotic peptides in animal species.
“The alligator’s leukocytes secrete small peptides capable of killing many of the microbes that modern antibiotics can’t touch, including MRSA – a resistant strain of Staphylococcus aureus thought to be responsible for 70% of the lethal infections contracted in US hospitals. The Denmark-based biotechnology company, Novozymes, found a rare antibiotic peptide in Pseudoplectania nigrella, a black fungus that grows in European pine forests. one of them [was similar] to a known class of antibiotic peptides called defensins.” Named plectasin, Novoymes’ defensin kills aggressive strains of Streptococcus pneumoniae. Since the 2005 discovery, the company has screened more than 660 variants of the peptide, and identified the most potent one. Animal trials are underway, and the company hopes to move the peptide to the clinic in 2010."
These news have a wide positive impact on health and quality of life, so it is important to operate the dissemination and favour the kick off of their introduction and use for therapy. From a bioogical point of view, it would be interesting also to find which is the mechanism of activity, so studies on the interplay between bacteria and peptides are necessary. One of the known mechanisms of action is the introduction of pores in the membranes and the efflux of water by destruction of membrane potential. Other mechanims may be present too. Also in plants, peptides coded within defence proteins have been screened for antimicrobial and antifungal activities.
It is true that many transcripts coded in human and non-human genomes contain open reading frames that could potentially be translated into peptides (short Orfeome is assumed to account to 30000 potential peptides)
some of which has very uncommon high content (46%) of phenylalanine (AK023690), a high hydrophobicity feature that may be important for membrane localisation.
Not much is known also on peptides encoded within common proteins, as hemoglobin. Although these are not involved in defence activities, the protelysis of abundant proteins may generate peptides with peculiar bioactive proprieties (anti-hypertensive activity in fish muscle, meat and plant globulins, oppiod-like activity in caseins, etc..).
This forum wants to ask to this audience to submit information on the research in progress and on all the aspects of bioactivity studies, applications, stability and delivery through various encapsulation systems.