Two outer membrane proteins are bovine lactoferrin-binding proteins in Mannheimia haemolytica A1

Abstract

Mannheimia haemolytica is a Gram negative bacterium that is part of the bovine respiratory disease, which causes important economic losses in the livestock industry. In the present work, the interaction between M. haemolytica A1 and bovine lactoferrin (BLf) was studied. This iron-chelating glycoprotein is part of the mammalian innate-immune system and is present in milk and mucosal secretions; Lf is also contained in neutrophils secondary granules, which release this glycoprotein at infection sites. It was evidenced that M. haemolytica was not able to use iron-charged BLf (BholoLf) as a sole iron source; nevertheless, iron-lacked BLf (BapoLf) showed a bactericidal effect against M. haemolytica with MIC of 4.88 ± 1.88 and 7.31 ± 1.62 μM for M. haemolytica strain F (field isolate) and M. haemolytica strain R (reference strain), respectively. Through overlay assays and 2-D electrophoresis, two OMP of 32.9 and 34.2 kDa with estimated IP of 8.18 and 9.35, respectively, were observed to bind both BapoLf and BholoLf; these OMP were identified by Maldi-Tof as OmpA (heat-modifiable OMP) and a membrane protein (porin). These M. haemolytica BLf binding proteins could be interacting in vivo with both forms of BLf depending on the iron state of the bovine.Electronic supplementary materialThe online version of this article (doi:10.1186/s13567-016-0378-1) contains supplementary material, which is available to authorized users.

Lactoferrin: Balancing Ups and Downs of Inflammation Due to Microbial Infections

“…As mentioned above, most results indicate that Lf from different origins can exert bacteriostatic effects due to its iron-chelating activity, but it can also be bactericidal due to its interaction with LPS and porins in Gram-negative bacteria, or with teichoic acids in Gram-positive bacteria. These interactions lead to membrane damage and bacterial death [38,45,46,47,48,49,50,51,52,53,54]. Moreover, the antimicrobial activity of Lf is also highly dependent on its cationic properties, because the addition of positive charges to Lf via amidation enhances its antibacterial and antiviral properties and, in contrast, the addition of negative charges by acylation abolishes them [55].…”

Lactoferrin: A Powerful Antimicrobial Protein Present in Milk

“…The ability of bLf to reduce some bacterial virulence factors, such as those promoting adhesion to swine buccal epithelial cells and activity of secreted proteases in A. pleuropneumoniae, was demonstrated. In the case of M. haemolytica, two bLf binding proteins were described [6,19]. In respect to synthetic cationic peptides derived from bLf, they were tested against the pathogenic foodborne bacteria Vibrio parahaemolyticus and Vibrio cholerae; a significant decrease in bacterial growth was observed when bLf or bLfcin chimaera was used.…”

“…[37] -Three S. aureus isolates were susceptible to bLf at 0.67 (mg/ml) -Bacteriostatic effect and concentration-dependent was observed at 16h V. parahaemolyticus 17802 (6) , O3:K6 (7) , 727 (8) ; V. cholerae O1 and no-O1 bLf from DMV International (USA); bLfcin, bLfampin and bLfcin chimaera were prepared (9) ; bLf 20% iron; [ ]* 0.001,0.01, 0.02, 0.04 -bLf and bLf chimaera inhibited the V. parahaemolyticus growth in >50%; bLfcin and bLfampin in 10-15% [38] -bLf decreased the V. cholerae growth in >90%…”

“…[53] -apo-hLf caused cell lysis -The mechanism involved was caused by the binding of proteins to amoeba membrane E. histolytica HM 1:IMSS bLf, apo-hLf and bLfcin (6) (fragment [4][5][6][7][8][9][10][11][12][13][14] [ ]* 1.0, 2.5 -bLf and hLf were amoebicidal [54] -Effect was concentration-dependent and modulated by environmental conditions -bLf was more effective than bLfcin -All components synergized with metronidazole vs amoebae E. histolytica HM 1:IMSS bLfcin, bLfampin and bLf chimera (7) [ ]* 0.025, 0.050, 0.075, 0.10 -bLfcin and bLfampin had a moderate amoebicidal effect [55] -bLfcin chimera showed the highest microbicidal activity -The microbicidal effect of Lf peptides was iron-independent G. duodenalis bLf, bLfcin, hLf, Lfcin (2) [ ]* bLfcin and hLfcin: 0-0.024; bLf and hLf: 0-2.5 -LD50: bLfcin: 8 (µg/ml); bLf: 1.2 (mg/ml); hLfcin: 16 (µg/ml); hLf: 1.5 (mg/ml)…”

“…In addition, Lf is bactericidal, by binding to lipopolysaccharide (LPS), porins, and other outer membrane (OM) proteins in Gram-negative bacteria [6]; likewise, Lf can bind to teichoic acid in Gram-positive bacteria. All these actions cause disruption of the bacterial membrane, leading to cell lysis [7,8] bLf affects biofilm production [9][10][11], diminishes the release of toxins [12], and interferes with the adhesion of bacteria to host cells [9,[13][14][15][16].…”