scholarly journals Highly potent antimicrobial peptides from N-terminal membrane-binding region of E. coli MreB

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Karabi Saikia ◽  
Yalavarthi Durga Sravani ◽  
Vibin Ramakrishnan ◽  
Nitin Chaudhary
Keyword(s):  
Antimicrobial Peptides ◽  
Membrane Binding ◽  
Binding Region ◽  
E Coli

scholarly journals Proteomic response of Escherichia coli to a membrane lytic and iron chelating truncated Amaranthus tricolor defensin

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Tessa B. Moyer ◽  
Ashleigh L. Purvis ◽  
Andrew J. Wommack ◽  
Leslie M. Hicks
Keyword(s):  
Escherichia Coli ◽  
Antibacterial Activity ◽  
Antimicrobial Peptides ◽  
Mechanism Of Action ◽  
Gram Negative Bacteria ◽  
Amaranthus Tricolor ◽  
Core Motif ◽  
Gram Negative ◽  
E Coli ◽  
Membrane Lysis

Abstract Background Plant defensins are a broadly distributed family of antimicrobial peptides which have been primarily studied for agriculturally relevant antifungal activity. Recent studies have probed defensins against Gram-negative bacteria revealing evidence for multiple mechanisms of action including membrane lysis and ribosomal inhibition. Herein, a truncated synthetic analog containing the γ-core motif of Amaranthus tricolor DEF2 (Atr-DEF2) reveals Gram-negative antibacterial activity and its mechanism of action is probed via proteomics, outer membrane permeability studies, and iron reduction/chelation assays. Results Atr-DEF2(G39-C54) demonstrated activity against two Gram-negative human bacterial pathogens, Escherichia coli and Klebsiella pneumoniae. Quantitative proteomics revealed changes in the E. coli proteome in response to treatment of sub-lethal concentrations of the truncated defensin, including bacterial outer membrane (OM) and iron acquisition/processing related proteins. Modification of OM charge is a common response of Gram-negative bacteria to membrane lytic antimicrobial peptides (AMPs) to reduce electrostatic interactions, and this mechanism of action was confirmed for Atr-DEF2(G39-C54) via an N-phenylnaphthalen-1-amine uptake assay. Additionally, in vitro assays confirmed the capacity of Atr-DEF2(G39-C54) to reduce Fe3+ and chelate Fe2+ at cell culture relevant concentrations, thus limiting the availability of essential enzymatic cofactors. Conclusions This study highlights the utility of plant defensin γ-core motif synthetic analogs for characterization of novel defensin activity. Proteomic changes in E. coli after treatment with Atr-DEF2(G39-C54) supported the hypothesis that membrane lysis is an important component of γ-core motif mediated antibacterial activity but also emphasized that other properties, such as metal sequestration, may contribute to a multifaceted mechanism of action.

scholarly journals Lipocalin 2: A New Antimicrobial in Mast Cells

2019 ◽  
Vol 20 (10) ◽  
pp. 2380 ◽  
Author(s):  
Yu-Ling Chang ◽  
Zhenping Wang ◽  
Satomi Igawa ◽  
Jae Eun Choi ◽  
Tyler Werbel ◽  
...  
Keyword(s):  
Mast Cells ◽  
Antimicrobial Peptides ◽  
Antimicrobial Peptide ◽  
Bacterial Growth ◽  
Immune Defense ◽  
Lipocalin 2 ◽  
Vitro Assay ◽  
E Coli ◽  
Sphingosine 1 Phosphate

Mast cells (MCs) play a significant role in the innate immune defense against bacterial infection through the release of cytokines and antimicrobial peptides. However, their antimicrobial function is still only partially described. We therefore hypothesized that MCs express additional antimicrobial peptides. In this study, we used FANTOM 5 transcriptome data to identify for the first time that MCs express lipocalin 2 (LCN2), a known inhibitor of bacterial growth. Using MCs derived from mice which were deficient in LCN2, we showed that this antimicrobial peptide is an important component of the MCs’ antimicrobial activity against Escherichia coli (E. coli). Since sphingosine-1-phosphate receptors (S1PRs) on MCs are known to regulate their function during infections, we hypothesized that S1P could activate LCN2 production in MCs. Using an in vitro assay, we demonstrated that S1P enhances MCs antimicrobial peptide production and increases the capacity of MCs to directly kill S. aureus and E. coli via an LCN2 release. In conclusion, we showed that LCN2 is expressed by MCs and plays a role in their capacity to inhibit bacterial growth.

scholarly journals Induction of the Cpx Envelope Stress Pathway Contributes to Escherichia coli Tolerance to Antimicrobial Peptides

2013 ◽  
Vol 79 (24) ◽  
pp. 7770-7779 ◽  
Author(s):  
Bianca Audrain ◽  
Lionel Ferrières ◽  
Amira Zairi ◽  
Guillaume Soubigou ◽  
Curtis Dobson ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Peptides ◽  
Antimicrobial Peptide ◽  
Polymyxin B ◽  
Genetic Response ◽  
Content Type ◽  
E Coli ◽  
Multiresistant Bacteria ◽  
Envelope Stress ◽  
Stress Pathway

ABSTRACTAntimicrobial peptides produced by multicellular organisms as part of their innate system of defense against microorganisms are currently considered potential alternatives to conventional antibiotics in case of infection by multiresistant bacteria. However, while the mode of action of antimicrobial peptides is relatively well described, resistance mechanisms potentially induced or selected by these peptides are still poorly understood. In this work, we studied the mechanisms of action and resistance potentially induced by ApoEdpL-W, a new antimicrobial peptide derived from human apolipoprotein E. Investigation of the genetic response ofEscherichia coliupon exposure to sublethal concentrations of ApoEdpL-W revealed that this antimicrobial peptide triggers activation of RcsCDB, CpxAR, and σEenvelope stress pathways. This genetic response is not restricted to ApoEdpL-W, since several other antimicrobial peptides, including polymyxin B, melittin, LL-37, and modified S4dermaseptin, also activate severalE. colienvelope stress pathways. Finally, we demonstrate that induction of the CpxAR two-component system directly contributes toE. colitolerance toward ApoEdpL-W, polymyxin B, and melittin. These results therefore show thatE. colisenses and responds to different antimicrobial peptides by activation of the CpxAR pathway. While this study further extends the understanding of the array of peptide-induced stress signaling systems, it also provides insight into the contribution of Cpx envelope stress pathway toE. colitolerance to antimicrobial peptides.

scholarly journals A19F-NMR study of the membrane-binding region of D-lactate dehydrogenase ofescherichia coli

1993 ◽  
Vol 2 (11) ◽  
pp. 1938-1947 ◽  
Author(s):  
Zhen-Yu Sun ◽  
Hoai-Thu N. Truong ◽  
E. A. Pratt ◽  
David C. Sutherland ◽  
Christine E. Kulig ◽  
...  
Keyword(s):  
Lactate Dehydrogenase ◽  
Membrane Binding ◽  
Ofescherichia Coli ◽  
Binding Region ◽  
Nmr Study

scholarly journals Avian [beta]-defensins as antimicrobial and immunomodulatory agents

2018 ◽  
Author(s):  
◽  
Ming Yang
Keyword(s):  
Dendritic Cells ◽  
Antimicrobial Peptides ◽  
Animal Health ◽  
Host Cells ◽  
Manufacturing Cost ◽  
Experimental Conditions ◽  
Extended Spectrum Beta Lactamase ◽  
E Coli ◽  
Immature Dendritic Cells ◽  
Beta Defensins

The increasing prevalence of antibiotic-resistance and lack of effective antibiotics pose a serious threat to animal health and public health. Host antimicrobial peptides (AMPs) show broad-spectrum antimicrobial activity against various microbes with low potential for resistance development, compared to conventional antibiotics, indicating great potentials as therapeutic agents. Despite such promise, several limitations hinder the application of AMPs in the clinic, including high manufacturing cost, cytotoxicity, and stability in physiological conditions. New strategies are needed to solve those problems for their application. Avian beta-defensins (AvBD) are small, cationic, antimicrobial peptides. The potential application of AvBDs as antibiotic alternatives against antibiotic-resistant and zoonotic bacterial pathogens has been the subject of interest. In the first study, the biological functions of two AvBDs, AvBD-6 and AvBD-12, were determined under various experimental conditions. The results showed that AvBD-6 (+7) was more potent than AvBD-12 (+1) against E. coli, S. Typhimurium, and S. aureus as well as clinical isolates of extended-spectrum beta-lactamase (ESBL)-producing E. coli and K. pneumoniae. The antibacterial activity of AvBDs was greatly compromised under physiological salt concentrations. Both AvBDs demonstrated mild chemotactic property for chicken macrophages and AvBD-12, at relatively high concentrations, could also induce the migration of murine immature dendritic cells. The chemotactic property required the presence of chemokine receptor 2 (CCR2) on host cells and the conserved disulfide bridges of the peptides. The two AvBDs were nontoxic to CHO-K1, macrophages, or immature dendritic cells.

scholarly journals BIOLOGICAL ACTIVITY OF ANTIMICROBIAL PEPTIDES FROM CHICKENS THROMBOCYTES

2016 ◽  
pp. 24-29
Author(s):  
M. V. Sycheva ◽  
A. S. Vasilchenko ◽  
E. A. Rogozhin ◽  
T. M. Pashkova ◽  
L. P. Popova ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Antimicrobial Peptides ◽  
High Performance ◽  
Bactericidal Effect ◽  
Reverse Phase ◽  
Chromatography Method ◽  
E Coli ◽  
Liquid Chromatography Method ◽  
First Time ◽  
Peptide Fractions

Aim. Isolation and study ofbiological activity of antimicrobial peptides from chickens thrombocytes. Materials and methods. Peptides from chickens thrombocytes, obtained by reverse-phase high-performance liquid chromatography method with stepped and linear gradients of concentration increase of the organic solvent were used in the study. Their antimicrobial activity was determined by microtitration method in broth; mechanism of biological effect - by using fluorescent spectroscopy method with DNA-tropic dyes. Results. Individual fractions of peptides were isolated from chickens thrombocytes, that possess antimicrobial activity against Staphylococcus aureus P209 and Escherichia coli K12. A disruption of integrity of barrier structures of microorganisms under the effect of thrombocyte antimicrobial peptides and predominance of cells with damaged membrane in the population of E. coli was established. Conclusion. The data obtained on antimicrobial activity and mechanism of bactericidal effect of the peptide fractions from chickens thrombocytes isolated for the first time expand the understanding of functional properties of chickens thrombocytes and open a perspective for their further study with the aim of use as antimicrobial means.

scholarly journals Deep learning regression model for antimicrobial peptide design

2019 ◽  
Author(s):  
Jacob Witten ◽  
Zack Witten
Keyword(s):  
Neural Network ◽  
Antimicrobial Peptides ◽  
Network Architecture ◽  
State Of The Art ◽  
Machine Learning Techniques ◽  
Neural Network Architecture ◽  
Antibiotic Resistant ◽  
E Coli ◽  
Naturally Occurring ◽  
Learning Techniques

AbstractAntimicrobial peptides (AMPs) are naturally occurring or synthetic peptides that show promise for treating antibiotic-resistant pathogens. Machine learning techniques are increasingly used to identify naturally occurring AMPs, but there is a dearth of purely computational methods to design novel effective AMPs, which would speed AMP development. We collected a large database, Giant Repository of AMP Activities (GRAMPA), containing AMP sequences and associated MICs. We designed a convolutional neural network to perform combined classification and regression on peptide sequences to quantitatively predict AMP activity against Escherichia coli. Our predictions outperformed the state of the art at AMP classification and were also effective at regression, for which there were no publicly available comparisons. We then used our model to design novel AMPs and experimentally demonstrated activity of these AMPs against the pathogens E. coli, Pseudomonas aeruginosa, and Staphylococcus aureus. Data, code, and neural network architecture and parameters are available at https://github.com/zswitten/Antimicrobial-Peptides.

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