Lipid-mediated resistance of Gram-negative bacteria against various pore-forming antimicrobial peptides

Gutsmann, Thomas; Hagge, Sven O.; David, Alexander; Roes, Stefanie; Böhling, Arne; Hammer, Malte U.; Seydel, Ulrich

doi:10.1179/096805105x37330

Cited by 17 publications

(13 citation statements)

References 28 publications

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“…Collaterally, the insensitivity of E. coli under the chosen test conditions might probably result from the amount of peptides sequestered by more bacterial lipopolysaccharide (LPS) due to the higher cell number (7) and/or a changed net charge, structural order, or fluidity of the E. coli inner membrane under the changed physiological conditions during anaerobic growth in minimal medium. The latter growth conditions have been described by other groups to be variables influencing antimicrobial efficiency of AMPs (18,23,42,58).…”

Section: Discussionmentioning

confidence: 99%

Effects of Antimicrobial Peptides on Methanogenic Archaea

Bang

Schilhabel

Weidenbach

et al. 2012

Antimicrob Agents Chemother

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cAs members of the indigenous human microbiota found on several mucosal tissues, Methanobrevibacter smithii and Methanosphaera stadtmanae are exposed to the effects of antimicrobial peptides (AMPs) secreted by these epithelia. Although antimicrobial and molecular effects of AMPs on bacteria are well described, data for archaea are not available yet. Besides, it is not clear whether AMPs affect them as the archaeal cell envelope differs profoundly in terms of chemical composition and structure from that of bacteria. The effects of different synthetic AMPs on growth of M. smithii, M. stadtmanae, and Methanosarcina mazei were tested using a microtiter plate assay adapted to their anaerobic growth requirements. All three tested methanoarchaea were highly sensitive against derivatives of human cathelicidin, of porcine lysin, and a synthetic antilipopolysaccharide peptide (Lpep); however, sensitivities differed markedly among the methanoarchaeal strains. The potent AMP concentrations affecting growth were below 10 M, whereas growth of Escherichia coli WBB01 was not affected at peptide concentrations up to 10 M under the same anaerobic growth conditions. Atomic force microscopy and transmission electron microscopy revealed that the structural integrity of the methanoarchaeal cells is destroyed within 4 h after incubation with AMPs. The disruption of the cell envelope of M. smithii, M. stadtmanae, and M. mazei within a few minutes of exposure was verified by using LIVE/DEAD staining. Our results strongly suggest that the release of AMPs by eukaryotic epithelial cells is a potent defense mechanism targeting not only bacteria, but also methanoarchaea.

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Section: Discussionmentioning

confidence: 99%

Effects of Antimicrobial Peptides on Methanogenic Archaea

Bang

Schilhabel

Weidenbach

et al. 2012

Antimicrob Agents Chemother

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“…Therefore, we evaluated the resistance of the three mutants to the antimicrobial peptide polymyxin B. A wealth of data indicates that resistance to this peptide reflects well the resistance to other mammalian peptides (29,35,51,75). When the strains were grown at 21°C, the MIC of polymyxin B for the lpxP mutant (0.32 Ϯ 0.04 U/ml) was significantly lower (P Ͻ 0.05) than those for the wild-type and msbB and htrB mutant strains (0.48 Ϯ 0.02, 0.42 Ϯ 0.02, and 0.42 Ϯ 0.03 U/ml, respectively).…”

Section: Resultsmentioning

confidence: 99%

Role of Lipid A Acylation in Yersinia enterocolitica Virulence

et al. 2010

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Yersinia enterocolitica is an important human pathogen. Y. enterocolitica must adapt to the host environment, and temperature is an important cue regulating the expression of most Yersinia virulence factors. Here, we report that Y. enterocolitica 8081 serotype O:8 synthesized tetra-acylated lipid A at 37°C but that hexa-acylated lipid A predominated at 21°C. By mass spectrometry and genetic methods, we have shown that the Y. enterocolitica msbB, htrB, and lpxP homologues encode the acyltransferases responsible for the addition of C 12 , C 14 and C 16:1 , respectively, to lipid A. The expression levels of the acyltransferases were temperature regulated. Levels of expression of msbB and lpxP were higher at 21°C than at 37°C, whereas the level of expression of htrB was higher at 37°C. At 21°C, an lpxP mutant was the strain most susceptible to polymyxin B, whereas at 37°C, an htrB mutant was the most susceptible. We present evidence that the lipid A acylation status affects the expression of Yersinia virulence factors. Thus, expression of flhDC, the flagellar master regulatory operon, was downregulated in msbB and lpxP mutants, with a concomitant decrease in motility. Expression of the phospholipase yplA was also downregulated in both mutants. inv expression was downregulated in msbB and htrB mutants, and consistent with this finding, invasion of HeLa cells was diminished. However, the expression of rovA, the positive regulator of inv, was not affected in the mutants. The levels of pYV-encoded virulence factors Yops and YadA in the acyltransferase mutants were not affected. Finally, we show that only the htrB mutant was attenuated in vivo.

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“…However, these peptides have limitations, being active only at high (μM) concentration (33) and often rendered inactive by bacterial resistance (34,35). The appropriate linking of the recognition protein with a lytic peptide increases the overall antimicrobial activity of the chimera by several-fold over a lytic peptide alone (such as cecropin) or a combination of two lytic peptides (such as cecropin and melittin) with similar modes of action.…”

Section: Discussionmentioning

confidence: 99%

An engineered innate immune defense protects grapevines from Pierce disease

Dandekar

Gouran

Ibáñez

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

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We postulated that a synergistic combination of two innate immune functions, pathogen surface recognition and lysis, in a protein chimera would lead to a robust class of engineered antimicrobial therapeutics for protection against pathogens. In support of our hypothesis, we have engineered such a chimera to protect against the Gram-negative Xylella fastidiosa (Xf), which causes diseases in multiple plants of economic importance. Here we report the design and delivery of this chimera to target the Xf subspecies fastidiosa (Xff), which causes Pierce disease in grapevines and poses a great threat to the wine-growing regions of California. One domain of this chimera is an elastase that recognizes and cleaves MopB, a conserved outer membrane protein of Xff. The second domain is a lytic peptide, cecropin B, which targets conserved lipid moieties and creates pores in the Xff outer membrane. A flexible linker joins the recognition and lysis domains, thereby ensuring correct folding of the individual domains and synergistic combination of their functions. The chimera transgene is fused with an amino-terminal signal sequence to facilitate delivery of the chimera to the plant xylem, the site of Xff colonization. We demonstrate that the protein chimera expressed in the xylem is able to directly target Xff, suppress its growth, and significantly decrease the leaf scorching and xylem clogging commonly associated with Pierce disease in grapevines. We believe that similar strategies involving protein chimeras can be developed to protect against many diseases caused by human and plant pathogens.

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Lipid-mediated resistance of Gram-negative bacteria against various pore-forming antimicrobial peptides

Cited by 17 publications

References 28 publications

Effects of Antimicrobial Peptides on Methanogenic Archaea

Effects of Antimicrobial Peptides on Methanogenic Archaea

Role of Lipid A Acylation in Yersinia enterocolitica Virulence

An engineered innate immune defense protects grapevines from Pierce disease

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