A cecropin-like peptide, papiliocin, isolated from the swallowtail butterfly Papilio xuthus, possesses high selectivity against gram-negative bacteria. Since Trp(2) and Phe(5) are highly conserved residues in cecropin-like peptides, we investigated the role of Trp(2) and Phe(5) in antibacterial activity. Substitution of Trp(2) and Phe(5) in papiliocin with Ala (papiliocin-2A and papiliocin-5A) ...

Peptides derived from LfcinB were designed and synthesized, and their antibacterial activity was tested against Escherichia coli ATCC 25922 and Staphylococcus aureus ATCC 25923. Specifically, a peptide library was constructed by systemically removing the flanking residues (N or C-terminal) of Lfcin 17-31 (17FKCRRWQWRMKKLGA31), maintaining in all peptides the 20RRWQWR25 sequence that corresponds...

Linear, dimeric, tetrameric, and cyclic peptides derived from lactoferricin B, containing the RRWQWR motif, were designed, synthesized, purified, and characterized using RP-HPLC chromatography and MALDI-TOF mass spectrometry. The antibacterial activity of the designed peptides against E. coli (ATCC 11775 and 25922) and their cytotoxic effect against MDA-MB-468 and MDA-MB-231 breast cancer cell ...

A novel antimicrobial peptide, GAPI, has been developed recently by grafting gallic acid (GA) to polyphemusin I (PI). The objective of this study was investigate the antibacterial effects GAPI on common oral pathogens. This laboratory used minimum inhibitory concentrations and bactericidal assess properties against Transmission electron microscopy examine bacterial morphology both before after ...

Bacteria and viruses may enter our bodies through mucous membranes of the airways or gut. To prevent infections, one defense mechanism immune system is antimicrobial peptides (AMPs). Most AMPs are composed 10–50 amino acids insert into bacterial cell to destroy cell. Some also active against fungi. can be generated by chopping up bigger proteins like hemoglobin. The hemoglobin fragments inactiv...

Antisense oligodeoxynucleotides (ODNs) and their analogs have been successfully utilized to inhibit gene expression and bacterial growth in vitro or in cell culture. In this study, acpP-targeting antisense peptide nucleic acid (PNA) and its peptide conjugate were tested as potential antibacterial agents in two groups of experiments using a mouse model. In the first group, Escherichia coli mutan...

BACKGROUND Since bactericidal properties of some lysozymes are independent of their glycosidase activity, we have investigated this phenomenon for destabilase-lysozyme (DL) from medicinal leech (Hirudo medicinalis). METHODS Glycosidase activity was determined on Micrococcus luteus, non-enzymatic antibacterial activity of heat-treated DL and of synthetic peptides alpha1, alpha2 and alpha3 (fra...

The development of new antibacterial agents, particularly those with unique biological targets, is essential to keep pace with the inevitable emergence of drug resistance in pathogenic bacteria. We identified the minimal structural component of the cyclic acyldepsipeptide (ADEP) antibiotics that exhibits antibacterial activity. We found that N-acyldifluorophenylalanine fragments function via th...

Antibacterial peptides were isolated from immune haemolymph of Rhinoceros beetle (Oryctes rhinoceros L.) larvae and evaluated for antibacterial activity against bacterial pathogens, viz., Klebsiella pneumoniae, Micrococcus luteus, Bacillus subtilis, Paenebacillus macerans and Pseudomonas sp. The peptides were found to be stable upto 37°C and antibacterial activity observed at pH 7.0. The peptid...

The seventh residue of thiostrepton is predicted to be critical for antibacterial activity. Substitution of Thr7 in the thiostrepton precursor peptide disrupts both biological activity and the successful biosynthesis of analogs.