1. Assessment of spermicidal activity of the antimicrobial peptide sarcotoxin Pd: A potent contraceptive agent
Hadi Zare-Zardini, Farzaneh Fesahat, Fatemeh Anbari, Iman Halvaei, Leila Ebrahimi Eur J Contracept Reprod Health Care. 2016;21(1):15-21. doi: 10.3109/13625187.2015.1052395. Epub 2015 Jun 8.
Objectives: In searching for new spermicidal microbicides for use in the prevention of unplanned pregnancy and sexually transmitted infections (STIs) we investigated the spermicidal and cytotoxicity activities of the antimicrobial peptide sarcotoxin Pd. Methods: Washed sperm from 10 healthy, normal volunteers was treated with different concentrations of sarcotoxin Pd. Sperm motility and morphology were assessed at 0, 0.3, 5, 10 and 15 min. The cytotoxicity of sarcotoxin Pd in normal human cervical HeLa cells was measured. Percentage cell survival was expressed as the number of live cells in the test group. Results: The cytotoxic effect of sarcotoxin Pd was concentration-dependent. Significant cytotoxicity was observed at concentrations above 24 μg/ml. Sarcotoxin Pd immobilised 100% of spermatozoa at a dose of 90 and 80 μg/ml after 0.3 and 5 min, respectively, and immobilised 50% of spermatozoa after 15 min at lower doses. Sarcotoxin Pd inhibited sperm motility in a dose-dependent manner. The peptide immobilised sperm within 20 s at its maximal effective concentration of 90 μg/ml. Conclusions: Sarcotoxin Pd appears to be a good candidate for a contraceptive agent in the prevention of unplanned pregnancy and STIs.
2. Saccharomyces cerevisiae cells harboring the gene encoding sarcotoxin IA secrete a peptide that is toxic to plant pathogenic bacteria
R Aly, D Granot, Y Mahler-Slasky, N Halpern, D Nir, E Galun Protein Expr Purif. 1999 Jun;16(1):120-4. doi: 10.1006/prep.1999.1059.
Sarcotoxin IA is a cecropin-type antibacterial protein produced by the flesh fly, Sarcophaga peregrina. Similar to other bactericidal small proteins produced by insects, sarcotoxin IA is released into the hemolymph of larvae and nymphs upon mechanical injury or bacterial infection. The gene (sarco) that encodes this toxin was introduced into Saccharomyces cerevisiae yeast cells and was expressed under a constitutive yeast promoter. The transformed yeast cells were grown in a liquid medium, and a peptide with a similar molecular size to that of the mature sarcotoxin IA was detected in the medium by Western blot analysis. The secreted sarcotoxin-like peptide (SLP) had a potent cytotoxic effect against several bacteria, including plant pathogenic bacteria, similar to the toxic effects of the authentic sarcotoxin IA. Erwinia carotovora was more susceptible to the toxic medium than Pseudomonas solanacearum and Pseudomonas syringae pv. lachrymans. Thus, yeast may be used in the production of such proteins for employment against various bacterial pathogens.
3. Participation of two N-terminal residues in LPS-neutralizing activity of sarcotoxin IA
Kazuo Okemoto, Yuki Nakajima, Toshiyuki Fujioka, Shunji Natori J Biochem. 2002 Feb;131(2):277-81. doi: 10.1093/oxfordjournals.jbchem.a003099.
Sarcotoxin IA is a cecropin-type antibacterial peptide of flesh fly. Using a mutant sarcotoxin IA lacking two N-terminal residues, we demonstrated that these residues are indispensable for its antibacterial activity against Escherichia coli and LPS-binding. Contrary to the native sarcotoxin IA, the mutant sarcotoxin IA could not neutralize various biological activities of LPS. It was suggested that sarcotoxin IA firmly binds to the lipid A core of LPS via these two N-terminal residues and forms a stable binding complex that exhibits no appreciable biological activity like native LPS.
