Related Experiment Video
Updated: Jun 16, 2026
10:13
Production and Visualization of Bacterial Spheroplasts and Protoplasts to Characterize Antimicrobial Peptide Localization
Published on: August 11, 2018
An enhancer peptide for membrane-disrupting antimicrobial peptides
Satoshi Ueno1, Kohtaro Kusaka, Yasushi Tamada
1Division of Insect Sciences, National Institute of Agrobiological Sciences, Oowashi 1-2, Tsukuba, Ibaraki 305-8634, Japan.
BMC Microbiology
|February 16, 2010
Summary
NP4P, a synthetic peptide, enhances the effectiveness of membrane-disrupting antimicrobial peptides against bacteria. This peptide boosts the antimicrobial activity by improving membrane disruption without being bactericidal itself.
Area of Science:
- Biochemistry
- Microbiology
- Peptide Science
Background:
- NP4P is a synthetic peptide derived from the pro-region of nematode cecropin P4.
- It is modified by replacing acidic amino acid residues with amides.
Purpose of the Study:
- To investigate the effect of NP4P on the activity of various antimicrobial peptides.
- To determine if NP4P enhances the bactericidal efficacy of antimicrobial agents.
Main Methods:
- Testing NP4P in combination with different antimicrobial peptides against microbial cultures.
- Assessing the minimum bactericidal concentration (MBC) of antimicrobial peptides in the presence and absence of NP4P.
- Evaluating the effect of NP4P on bacterial growth and membrane permeability.
Main Results:
- NP4P significantly lowered the MBC of membrane-disrupting peptides (e.g., ASABF-alpha, polymyxin B, nisin) against Staphylococcus aureus.
- NP4P itself showed no bactericidal activity and did not inhibit bacterial growth at concentrations up to 300 microg/mL.
- The activity of non-membrane-disrupting antimicrobials (indolicidin, ampicillin, kanamycin, enrofloxacin) was unaffected by NP4P.
- NP4P enhanced the membrane-disrupting efficacy of ASABF-alpha against S. aureus membranes.
Conclusions:
- NP4P selectively potentiates the bactericidal activity of membrane-disrupting antimicrobial peptides.
- This enhancement is achieved by increasing the efficacy of membrane disruption, particularly targeting the cytoplasmic membrane.
- NP4P represents a potential adjuvant for improving the performance of certain antimicrobial therapies.
Related Concept Videos
01:23Antimicrobial Proteins
Antimicrobial proteins are important components of the immune system. They aid the body in combating pathogens by either killing them directly or hindering their replication processes. Four main types of antimicrobial substances are interferons, the complement system, iron-binding proteins, and antimicrobial proteins.
Interferons
Interferons (IFNs) are proteins produced by lymphocytes, macrophages, and fibroblasts infected with viruses. While IFNs cannot prevent viruses from entering and...
Interferons
Interferons (IFNs) are proteins produced by lymphocytes, macrophages, and fibroblasts infected with viruses. While IFNs cannot prevent viruses from entering and...
01:19Translocation of Proteins into the Mitochondria
Mitochondrial precursors are translocated to the internal subcompartments via independent mechanisms involving distinct protein machineries called translocases.
Sorting of outer membrane proteins:
Mitochondrial outer membrane proteins are of two types: the transmembrane, beta-barrel porins, and the membrane-anchored, alpha-helical proteins. Beta-barrel porin precursors are translocated by the TOM complex and inserted into the outer mitochondrial membrane by the SAM complex. In contrast,...
Sorting of outer membrane proteins:
Mitochondrial outer membrane proteins are of two types: the transmembrane, beta-barrel porins, and the membrane-anchored, alpha-helical proteins. Beta-barrel porin precursors are translocated by the TOM complex and inserted into the outer mitochondrial membrane by the SAM complex. In contrast,...
01:23Inhibitors of Gram-positive Cell Wall Synthesis
Bacterial cell walls are typically rigid structures composed mainly of peptidoglycan, a mesh-like polymer that provides mechanical strength and maintains cell shape. The synthesis of peptidoglycan is a crucial process in bacterial growth and serves as a primary target for many antibiotics.Mechanism of Action of Beta-Lactam AntibioticsBeta-lactam antibiotics, such as penicillin, inhibit peptidoglycan synthesis in actively growing cells. These antibiotics share a characteristic four-membered...
01:26Insertion of Single-pass Transmembrane Proteins in the RER
Integral membrane proteins are proteins adhered to the lipid bilayer of a cell organelle or membrane. They can be of two types: transmembrane integral proteins that span the lipid bilayer and monotopic proteins that are attached to either side of the membrane but do not pass through it.
Integral transmembrane proteins possess transmembrane and extra membrane domains. The transmembrane domains are primarily made of 20-25 hydrophobic amino acids arranged in a helical secondary confirmation. These...
Integral transmembrane proteins possess transmembrane and extra membrane domains. The transmembrane domains are primarily made of 20-25 hydrophobic amino acids arranged in a helical secondary confirmation. These...
01:39Mitochondrial Precursor Proteins
Mitochondrial precursors are partially unfolded or loosely folded polypeptide chains. Newly synthesized precursors are inhibited from spontaneously folding into their native conformation by the cytosolic chaperones, heat shock proteins 70 (Hsp70), and mitochondrial import stimulation factors (MSFs). Precursors bound to MSFs are guided to the TOM70-TOM37 receptors, while precursors bound to Hsp70 chaperones are targetted to TOM20-TOM22 receptor complexes.
Most of the mitochondrial precursors...
Most of the mitochondrial precursors...