scholarly journals Lipid II-Based Antimicrobial Activity of the Lantibiotic Plantaricin C

2006 ◽  
Vol 72 (4) ◽  
pp. 2809-2814 ◽  
Author(s):  
Imke Wiedemann ◽  
Tim Böttiger ◽  
Raquel Regina Bonelli ◽  
Tanja Schneider ◽  
Hans-Georg Sahl ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Cell Wall ◽  
Pore Formation ◽  
Specific Interaction ◽  
Structural Features ◽  
Binding Motifs ◽  
Whole Cells ◽  
Lipid Ii

ABSTRACT We analyzed the mode of action of the lantibiotic plantaricin C (PlnC), produced by Lactobacillus plantarum LL441. Compared to the well-characterized type A lantibiotic nisin and type B lantibiotic mersacidin, which are both able to interact with the cell wall precursor lipid II, PlnC displays structural features of both prototypes. In this regard, we found that lipid II plays a key role in the antimicrobial activity of PlnC besides that of pore formation. The pore forming activity of PlnC in whole cells was prevented by shielding lipid II on the cell surface. However, in contrast to nisin, PlnC was not able to permeabilize Lactococcus lactis cells or to form pores in 1,2-dioleoyl-sn-glycero-3-phosphocholine liposomes supplemented with 0.1 mol% purified lipid II. This emphasized the different requirements of these lantibiotics for pore formation. Using cell wall synthesis assays, we identified PlnC as a potent inhibitor of (i) lipid II synthesis and (ii) the FemX reaction, i.e., the addition of the first Gly to the pentapeptide side chain of lipid II. As revealed by thin-layer chromatography, both reactions were clearly blocked by the formation of a PlnC-lipid I and/or PlnC-lipid II complex. On the basis of the in vivo and in vitro activities of PlnC shown in this study and the structural lipid II binding motifs described for other lantibiotics, the specific interaction of PlnC with lipid II is discussed.

scholarly journals Specific Interaction of the Unmodified Bacteriocin Lactococcin 972 with the Cell Wall Precursor Lipid II

2008 ◽  
Vol 74 (15) ◽  
pp. 4666-4670 ◽  
Author(s):  
Beatriz Martínez ◽  
Tim Böttiger ◽  
Tanja Schneider ◽  
Ana Rodríguez ◽  
Hans-Georg Sahl ◽  
...  
Keyword(s):  
Cell Wall ◽  
Molecular Basis ◽  
Pore Formation ◽  
Cytoplasmic Membrane ◽  
Specific Interaction ◽  
Whole Cells ◽  
Lipid Ii ◽  
Inhibitory Spectrum

ABSTRACT Lactococcin 972 (Lcn972) is a nonlantibiotic bacteriocin that inhibits septum biosynthesis in Lactococcus lactis rather than forming pores in the cytoplasmic membrane. In this study, a deeper analysis of the molecular basis of the mode of action of Lcn972 was performed. Of several lipid cell wall precursors, only lipid II antagonized Lcn972 inhibitory activity in vivo. Likewise, Lcn972 only coprecipitated with lipid II micelles. This bacteriocin inhibited the in vitro polymerization of lipid II by the recombinant S. aureus PBP2 and the addition to lipid II of the first glycine catalyzed by FemX. These experiments demonstrate that Lcn972 specifically interacts with lipid II, the substrate of both enzymes. In the presence of Lcn972, nisin pore formation was partially hindered in whole cells. However, binding of Lcn972 to lipid II could not compete with nisin in lipid II-doped 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) liposomes, possibly indicating a distinct binding site. The existence of a putative cotarget for Lcn972 activity is discussed in the context of its narrow inhibitory spectrum and the localized action at the division septum. To our knowledge, this is the first unmodified bacteriocin that binds to the cell wall precursor lipid II.

scholarly journals Insights into In Vivo Activities of Lantibiotics from Gallidermin and Epidermin Mode-of-Action Studies

2006 ◽  
Vol 50 (4) ◽  
pp. 1449-1457 ◽  
Author(s):  
Raquel Regina Bonelli ◽  
Tanja Schneider ◽  
Hans-Georg Sahl ◽  
Imke Wiedemann
Keyword(s):  
Cell Wall ◽  
Pore Formation ◽  
Specific Interaction ◽  
Binding Motif ◽  
Membrane Thickness ◽  
Peptide Antibiotics ◽  
Intact Cells ◽  
Lipid Ii ◽  
A Cell

ABSTRACT The activity of lanthionine-containing peptide antibiotics (lantibiotics) is based on different killing mechanisms which may be combined in one molecule. The prototype lantibiotic nisin inhibits peptidoglycan synthesis and forms pores through specific interaction with the cell wall precursor lipid II. Gallidermin and epidermin possess the same putative lipid II binding motif as nisin; however, both peptides are considerably shorter (22 amino acids, compared to 34 in nisin). We demonstrate that in model membranes, lipid II-mediated pore formation by gallidermin depends on membrane thickness. With intact cells, pore formation was less pronounced than for nisin and occurred only in some strains. In Lactococcus lactis subsp. cremoris HP, gallidermin was not able to release K+, and a mutant peptide, [A12L]gallidermin, in which the ability to form pores was disrupted, was as potent as wild-type gallidermin, indicating that pore formation does not contribute to killing. In contrast, nisin rapidly formed pores in the L. lactis strain; however, it was approximately 10-fold less effective in killing. The superior activity of gallidermin in a cell wall biosynthesis assay may help to explain this high potency. Generally, it appears that the multiple activities of lantibiotics combine differently for individual target strains.

scholarly journals Lipid II-Mediated Pore Formation by the Peptide Antibiotic Nisin: a Black Lipid Membrane Study

2004 ◽  
Vol 186 (10) ◽  
pp. 3259-3261 ◽  
Author(s):  
Imke Wiedemann ◽  
Roland Benz ◽  
Hans-Georg Sahl
Keyword(s):  
Cell Wall ◽  
Pore Formation ◽  
Cytoplasmic Membrane ◽  
Lipid Membrane ◽  
Specific Interaction ◽  
Peptide Antibiotic ◽  
Black Lipid Membrane ◽  
Lipid Ii ◽  
Antibiotic Peptide

ABSTRACT The antibiotic peptide nisin is the first known lantibiotic that uses a docking molecule within the bacterial cytoplasmic membrane for pore formation. Through specific interaction with the cell wall precursor lipid II, nisin forms defined pores which are stable for seconds and have pore diameters of 2 to 2.5 nm.

scholarly journals Postantibiotic and Sub-MIC Effects of Exebacase (Lysin CF-301) Enhance Antimicrobial Activity againstStaphylococcus aureus

2019 ◽  
Vol 63 (6) ◽  
Author(s):  
Jun Taek Oh ◽  
Cara Cassino ◽  
Raymond Schuch
Keyword(s):  
Antimicrobial Activity ◽  
Cell Wall ◽  
The United States ◽  
Infection Model ◽  
Postantibiotic Effect ◽  
Content Type ◽  
Wall Ultrastructure ◽  
Bacterial Fitness

ABSTRACTCF-301 (exebacase) is a recombinantly produced bacteriophage-derived lysin (cell wall hydrolase) and is the first agent of this class to enter clinical development in the United States for treating bacteremia including endocarditis due toStaphylococcus aureus. Whereas rapid bactericidal activity is the hallmarkin vitroandin vivoresponse to CF-301 at exposures higher than the MIC, prolonged antimicrobial activity, mediated by cell wall damage, is predicted at concentrations less than the MIC. In the current study, a series ofin vitropharmacodynamic parameters, including the postantibiotic effect (PAE), postantibiotic sub-MIC effect (PA-SME), and sub-MIC effect (SME), were studied to determine how short-duration and sub-MIC CF-301 exposures affect the growth of surviving staphylococci and extend its antimicrobial activity. Mean PAE, PA-SME, and SME values up to 4.8, 9.3, and 9.8 h, respectively, were observed against 14 staphylococcal strains tested in human serum; growth delays were extended by 6 h in the presence of daptomycin. Exposures to CF-301 at sub-MIC levels as low as 0.001× to 0.01× MIC (∼1 to 10 ng/ml) resulted in aberrant cell wall ultrastructure, increased membrane permeability, dissipation of membrane potential, and inhibition of virulence phenotypes, including agglutination and biofilm formation. A mouse thigh infection model designed to study the PAE was used to confirm our findings and demonstratein vivogrowth delays of ≥19.3 h. Our findings suggest that at CF-301 concentrations less than the MIC during therapeutic use, sustained reductions in bacterial fitness and virulence may substantially enhance efficacy.

scholarly journals In Vivo Effects of A Pro-PO System Inhibitor on the Phagocytosis of Xenorhabdus Nematophila in Galleria Mellonella Larvae

Insects ◽  
2019 ◽  
Vol 10 (9) ◽  
pp. 263 ◽  
Author(s):  
Andrea De Lerma Barbaro ◽  
Marzia B. Gariboldi ◽  
Maristella Mastore ◽  
Maurizio F. Brivio ◽  
Stefano Giovannardi
Keyword(s):  
Cell Wall ◽  
Galleria Mellonella ◽  
Mammalian Species ◽  
Specific Inhibitor ◽  
Fluorescein Isothiocyanate ◽  
Structural Features ◽  
In Vitro Tests ◽  
Xenorhabdus Nematophila

Xenorhabdus nematophila is a Gram-negative bacterium symbiont of the entomopathogen nematode Steinernema carpocapsae whose immunosuppressive properties over host’s immune response have been thoroughly investigated. In particular, live X. nematophila actively impairs phagocytosis in host’s hemocytes through the secretion of inhibitors of eicosanoids synthesis. In this article we have investigated the cell surface structural features of X. nematophila responsible for the elusion from phagocytosis. To this end we have studied the uptake of heat-killed (hk), fluorescein isothiocyanate (FITC)-labeled X. nematophila by phagocytes from both a host insect and a mammalian species. In vitro dead X. nematophila passively resists engulfment by insect hemocytes without impairing the phagocytosis machinery whereas, unexpectedly, in vivo a significant phagocytosis of dead X. nematophila was observed. X. nematophila in vivo phagocytosis was increased by the co-injection of the specific inhibitor of pro-phenoloxidase (PO) system phenylthiourea (PTU), even if these effects were not observed in in vitro tests. Furthermore, biochemical modifications of X. nematophila cell wall implement in vivo phagocytosis, suggesting that this bacterium avoid phagocytosis because the ligand of phagocytic receptors is somehow buried or disguised in the cell wall. Finally, dead X. nematophila escapes engulfment even by human phagocytes suggesting that X. nematophila could be a useful model to investigate escape from phagocytosis by mammalian macrophages.

An in vitro system for the biosynthesis of spore cortex peptidoglycan

1977 ◽  
Vol 23 (8) ◽  
pp. 964-974 ◽  
Author(s):  
Susanne M. Pearce
Keyword(s):  
Cell Wall ◽  
Germ Cell ◽  
Early Stage ◽  
Diaminopimelic Acid ◽  
In Vitro System ◽  
Whole Cells ◽  
Total Lack ◽  
Cortical System

A simple crude system for the incorporation of tritiated diaminopimelic acid (3H-DAP) into a polymer with characteristics of spore cortical peptidoglycan has been obtained from cells of Bacillus cereus var. alesti, harvested and disrupted in a French pressure cell, at the time of late cortex formation (sporulation stage 5). The small fraction of whole cells remaining in the homogenate were not responsible for the observed incorporation. The radioactive product was sensitive to digestion by lysozyme as is cortex formed in vivo. Preparations obtained at the same time of sporulation, from a mutant unable to form cortex, were unable to incorporate 3H-DAP into peptidoglycan. However, homogenates prepared at the time of germ cell wall formation (early stage 4) from both parent and cortexless mutant produced radioactive peptidoglycan which was more resistant to lysozyme as is germ cell wall produced in vivo in this species. Bacitracin and vancomycin inhibited incorporation of 3H-DAP into peptidoglycan by over 90% in both cell wall and cortical preparations. Methicillin caused a striking inhibition of 3H-DAP incorporation into peptidoglycan by the cortical system in contrast to its almost total lack of inhibition of the cell wall or germ cell wall systems. Over 90% of the DAP incorporated was the expected meso-isomer. 3H-DAP-labelled lipid intermediate was produced by the system. Cross-linking of newly synthesized material was observed. This in vitro system appears satisfactory for the further study of some aspects of the biosynthesis of cortical peptidoglycan.

scholarly journals Spatial and temporal localization of cell wall associated pili in Enterococcus faecalis

2021 ◽  
Author(s):  
Pei Yi Choo ◽  
Charles Wang ◽  
Michael VanNieuwenhze ◽  
Kimberly Kline
Keyword(s):  
Cell Wall ◽  
Cell Surface ◽  
Enterococcus Faecalis ◽  
General Rule ◽  
Cell Wall Synthesis ◽  
Lipid Ii ◽  
Growing Cell ◽  
Temporal Localization

Enterococcus faecalis relies upon a number of cell wall-associated proteins for virulence. One virulence factor is the sortase-assembled endocarditis and biofilm associated pilus (Ebp), an important factor for biofilm formation in vitro and in vivo. The current paradigm for sortase-assembled pilus biogenesis in Gram-positive bacteria is that the pilus sortase covalently links pilus monomers prior to recognition, while the housekeeping sortase cleaves at the LPXTG motif within the terminal pilin subunit, and subsequently attaches assembled pilus fiber to the growing cell wall at sites of new cell wall synthesis. While the cell wall anchoring mechanism and polymerization of Ebp is well characterized, less is known about the spatial and temporal deposition of this protein on the cell surface. We followed the distribution of Ebp and peptidoglycan (PG) throughout the E. faecalis cell cycle via immunofluorescence microscopy and fluorescent D-amino acids (FDAA) staining. Surprisingly, cell surface Ebp did not co-localize with newly synthesized PG. Instead, surface-anchored Ebp was localized to the cell hemisphere but never at the septum where new cell wall is deposited. In addition, the older hemisphere of the E. faecalis diplococcus were completely saturated with Ebp, while Ebp appeared as two foci directly adjacent to the nascent septum in the newer hemisphere. A similar localization pattern was observed for another cell wall anchored substrate by sortase A, aggregation substance (AS), suggesting that this may be a general rule for all SrtA substrates in E. faecalis. When cell wall synthesis was inhibited by ramoplanin, an antibiotic that binds and sequesters lipid II cell wall precursors, new Ebp deposition at the cell surface was not disrupted. These data suggest an alternative paradigm for sortase substrate deposition in E. faecalis, in which Ebp are anchored directly onto un-crosslinked cell wall, independent of new PG synthesis.

In vitro and in vivo polysaccharides assembly: ultrastructural and cytochemical study of growing plant cell wall components.

1978 ◽  
Vol 36 (2) ◽  
pp. 434-435
Author(s):  
D. Reis ◽  
B. Vian ◽  
J. C. Roland
Keyword(s):  
Cell Wall ◽  
Self Assembly ◽  
Plant Cell Wall ◽  
Higher Plants ◽  
Three Dimensional ◽  
Cytochemical Study ◽  
Wall Components

Wall morphogenesis in higher plants is a problem still open to controversy. Until now the possibility of a transmembrane control and the involvement of microtubules were mostly envisaged. Self-assembly processes have been observed in the case of walls of Chlamydomonas and bacteria. Spontaneous gelling interactions between xanthan and galactomannan from Ceratonia have been analyzed very recently. The present work provides indications that some processes of spontaneous aggregation could occur in higher plants during the formation and expansion of cell wall.Observations were performed on hypocotyl of mung bean (Phaseolus aureus) for which growth characteristics and wall composition have been previously defined.In situ, the walls of actively growing cells (primary walls) show an ordered three-dimensional organization (fig. 1). The wall is typically polylamellate with multifibrillar layers alternately transverse and longitudinal. Between these layers intermediate strata exist in which the orientation of microfibrils progressively rotates. Thus a progressive change in the morphogenetic activity occurs.

Traceable Peptidic Ligands that Target Ghrelin Receptors

2020 ◽  
Vol 21 (10) ◽  
pp. 955-964 ◽  
Author(s):  
Mengjie Liu ◽  
John Wade ◽  
Mohammed Akhter Hossain
Keyword(s):  
In Vivo Imaging ◽  
Peptide Hormone ◽  
Structural Features ◽  
Pharmacological Properties ◽  
Imaging Studies ◽  
Cognate Receptor ◽  
Ghrelin Receptors ◽  
Biochemical Research

: Ghrelin is a 28-amino acid octanoylated peptide hormone that is implicated in many physiological and pathophysiological processes. Specific visualization of ghrelin and its cognate receptor using traceable ligands is crucial in elucidating the localization, functions, and expression pattern of the peptide’s signaling pathway. Here 12 representative radio- and fluorescently-labeled peptide-based ligands are reviewed for in vitro and in vivo imaging studies. In particular, the focus is on their structural features, pharmacological properties, and applications in further biochemical research.

Correlation between in vitro and in vivo Data of Radiolabeled Peptide for Tumor Targeting

2019 ◽  
Vol 19 (12) ◽  
pp. 950-960
Author(s):  
Soghra Farzipour ◽  
Seyed Jalal Hosseinimehr
Keyword(s):  
Tumor Targeting ◽  
Single Photon ◽  
Specific Binding ◽  
Specific Interaction ◽  
Photon Emission ◽  
Emission Computed Tomography ◽  
Mixed Effect ◽  
Radiolabeled Peptides

Tumor-targeting peptides have been generally developed for the overexpression of tumor specific receptors in cancer cells. The use of specific radiolabeled peptide allows tumor visualization by single photon emission computed tomography (SPECT) and positron emission tomography (PET) tools. The high affinity and specific binding of radiolabeled peptide are focusing on tumoral receptors. The character of the peptide itself, in particular, its complex molecular structure and behaviors influence on its specific interaction with receptors which are overexpressed in tumor. This review summarizes various strategies which are applied for the expansion of radiolabeled peptides for tumor targeting based on in vitro and in vivo specific tumor data and then their data were compared to find any correlation between these experiments. With a careful look at previous studies, it can be found that in vitro unblock-block ratio was unable to correlate the tumor to muscle ratio and the success of radiolabeled peptide for in vivo tumor targeting. The introduction of modifiers’ approaches, nature of peptides, and type of chelators and co-ligands have mixed effect on the in vitro and in vivo specificity of radiolabeled peptides.

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