Antibacterial spectrum of lactoferricin B, a potent bactericidal peptide derived from the N-terminal region of bovine lactoferrin
TL;DR: Lactoferricin B was lethal, causing a rapid loss of colony-forming capability in most of the species tested, and Pseudomonas fluorescens, Enterococcus faecalis and Bifidobacterium bifidum strains were highly resistant to this peptide.
Abstract: A physiologically diverse range of Gram-positive and Gram-negative bacteria was found to be susceptible to inhibition and inactivation by lactoferricin B, a peptide produced by gastric pepsin digestion of bovine lactoferrin. The list of susceptible organisms includes Escherichia coli, Salmonella enteritidis, Klebsiella pneumoniae, Proteus vulgaris, Yersinia enterocolitica, Pseudomonas aeruginosa, Campylobacter jejuni, Staphylococcus aureus, Streptococcus mutans, Corynebacterium diphtheriae, Listeria monocytogenes and Clostridium perfringens. Concentrations of lactoferricin B required to cause complete inhibition of growth varied within the range of 0.3 to 150 micrograms/ml, depending on the strain and the culture medium used. The peptide showed activity against E. coli O111 over the range of pH 5.5 to 7.5 and was most effective under slightly alkaline conditions. Its antibacterial effectiveness was reduced in the presence of Na+, K+, Mg2+ or Ca2+ ions, or in the presence of various buffer salts. Lactoferricin B was lethal, causing a rapid loss of colony-forming capability in most of the species tested. Pseudomonas fluorescens, Enterococcus faecalis and Bifidobacterium bifidum strains were highly resistant to this peptide.
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TL;DR: In this article, the main forms of caprine and ovine caseino-macropeptides (CMP), which are the soluble C-terminal derivatives from the action of chymosin on β-casein during the milk clotting process of cheesemaking, have been identified and are a good source of antithrombotic peptides.
1,120 citations
Cites background from "Antibacterial spectrum of lactoferr..."
...Shortly afterwards, the antibacterial domains of bovine LF f(17–41) and human LF f(1–47), called, respectively, bovine and human lactoferricin (LFcin), were purified and identified (Bellamy et al., 1992)....
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TL;DR: In this review, the structures of a number of different Trp- and Arg-rich antimicrobial peptides are examined and some of the major mechanistic studies are presented.
875 citations
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TL;DR: This work reviews the scientific literature and attempts to stimulate consideration of the continued use of bioactive peptides and their expanded development as a commercial product.
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TL;DR: Its extensive antimicrobial activities were originally attributed to its ability to sequester essential iron, however, it is now established that it possesses bactericidal activities as a result of a direct interaction between the protein or lactoferrin-derived peptides.
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TL;DR: A wide spectrum of functions are ascribed to lactoferrin, which range from a role in the control of iron availability to immune modulation, and more research is necessary to obtain clarity with regard to the exact mechanism of action.
Abstract: Lactoferrin is a 703-amino acid glycoprotein originally isolated from milk Plasma lactoferrin is predominantly neutrophil derived but indications are that it may also be produced by other cells Lactoferrin in body fluids is found in the iron-free form, the monoferric form and in the diferric form Three isoforms of lactoferrin have been isolated, ie two with RNase activity (lactoferrin-beta and lactoferrin-gamma) and one without RNase activity (lactoferrin-alpha) Receptors for lactoferrin can be found on intestinal tissue, monocytes/macrophages, neutrophils, lymphocytes, platelets, and on certain bacteria A wide spectrum of functions are ascribed to lactoferrin These range from a role in the control of iron availability to immune modulation More research is necessary however to obtain clarity with regard to the exact mechanism of action of lactoferrin
676 citations
Cites background from "Antibacterial spectrum of lactoferr..."
...Lactoferricin B was shown to be lethal to a wide spectrum of microbes, and to rapidly inhibit the colony-forming capability of most species tested.(117) The bactericidal effect of lactoferrin is mediated by blistering, i....
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References
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TL;DR: The studies suggest this domain is the structural region responsible for the bacterial properties of lactoferrin, having effectiveness against various Gram-negative and Gram-positive bacteria at concentrations between 0.3 microM and 3.0 microM, depending on the target strain.
882 citations
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TL;DR: The D enantiomers of three naturally occurring antibiotics--cecropin A, magainin 2 amide, and melittin--were synthesized and it is suggested that the mode of action of these peptides on the membranes of bacteria, erythrocytes, plasmodia, and artificial lipid bilayers may be similar and involves the formation of ion-channel pores spanning the membranes, but without specific interaction with chiral receptors or enzymes.
Abstract: The D enantiomers of three naturally occurring antibiotics--cecropin A, magainin 2 amide, and melittin--were synthesized. In addition, the D enantiomers of two synthetic chimeric cecropin-melittin hybrid peptides were prepared. Each D isomer was shown by circular dichroism to be a mirror image of the corresponding L isomer in several solvent mixtures. In 20% hexafluoro-2-propanol the peptides contained 43-75% alpha-helix. The all-D peptides were resistant to enzymatic degradation. The peptides produced single-channel conductances in planar lipid bilayers, and the D and L enantiomers caused equivalent amounts of electrical conductivity. All of the peptides were potent antibacterial agents against representative Gram-negative and Gram-positive species. The D and L enantiomers of each peptide pair were equally active, within experimental error. Sheep erythrocytes were lysed by both D- and L-melittin but not by either isomer of cecropin A, magainin 2 amide, or the hybrids cecropin A-(1-13)-melittin-(1-13)-NH2 or cecropin A-(1-8)-melittin-(1-18)-NH2. The infectivity of the bloodstream form of the malaria parasite Plasmodium falciparum was also inhibited by the D and L hybrids. It is suggested that the mode of action of these peptides on the membranes of bacteria, erythrocytes, plasmodia, and artificial lipid bilayers may be similar and involves the formation of ion-channel pores spanning the membranes, but without specific interaction with chiral receptors or enzymes.
695 citations
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TL;DR: The authors showed that at least two of the cecropins originate from a gene duplication and that the biosynthesis has been initiated on RNA and tissue levels on both RNA and DNA levels.
Abstract: An inducible antibacterial activity is a main part of the immune system of the Cecropia moth and several other insects The active material is a family of small proteins called cecropins Sequence work shows that at least two of the cecropins originate from a gene duplication Work on the biosynthesis has been initiated on RNA and tissue levels
689 citations
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TL;DR: Dialysis chamber studies indicate that bacterial killing requires direct contact with lactoferrin, and work with purified LPS suggests that this relates to direct LPS-binding by the protein, suggesting that their interaction contributes to host defense.
Abstract: Although lactoferrin has antimicrobial activity, its mechanism of action is not full defined. Recently we have shown that the protein alters the Gram-negative outer membrane. As this membrane protects Gram-negative cells from lysozyme, we have studied whether lactoferrin's membrane effect could enhance the antibacterial activity of lysozyme. We have found that while each protein alone is bacteriostatic, together they can be bactericidal for strains of V. cholerae, S. typhimurium, and E. coli. The bactericidal effect is dose dependent, blocked by iron saturation of lactoferrin, and inhibited by high calcium levels, although lactoferrin does not chelate calcium. Using differing media, the effect of lactoferrin and lysozyme can be partially or completely inhibited; the degree of inhibition correlating with media osmolarity. Transmission electron microscopy shows that E. coli cells exposed to lactoferrin and lysozyme at 40 mOsm become enlarged and hypodense, suggesting killing through osmotic damage. Dialysis chamber studies indicate that bacterial killing requires direct contact with lactoferrin, and work with purified LPS suggests that this relates to direct LPS-binding by the protein. As lactoferrin and lysozyme are present together in high levels in mucosal secretions and neutrophil granules, it is probable that their interaction contributes to host defense.
686 citations
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TL;DR: Streptococcus mutans and Vibrio cholerae, but not Escherichia coli, were killed by incubation with purified human apolact oferrin, contingent upon the metal-chelating properties of the lactoferrin molecule.
Abstract: Streptococcus mutans and Vibrio cholerae, but not Escherichia coli, were killed by incubation with purified human apolactoferrin. Concentrations of lactoferrin below that necessary for total inhibition resulted in a marked reduction in viable colony-forming units. This bactericidal effect was contingent upon the metal-chelating properties of the lactoferrin molecule.
665 citations