scholarly journals Antimicrobial Peptides as Probes in Biosensors Detecting Whole Bacteria: A Review

Molecules ◽  
2020 ◽  
Vol 25 (8) ◽  
pp. 1998 ◽  
Author(s):  
Éric Pardoux ◽  
Didier Boturyn ◽  
Yoann Roupioz
Keyword(s):  
Antimicrobial Peptides ◽  
Bacterial Resistance ◽  
Molecular Probes ◽  
Growth Potential ◽  
New Drugs ◽  
Diagnostic Tools ◽  
Label Free ◽  
Bacterial Membranes ◽  
Global Issue ◽  
Cost Efficient

Bacterial resistance is becoming a global issue due to its rapid growth. Potential new drugs as antimicrobial peptides (AMPs) are considered for several decades as promising candidates to circumvent this threat. Nonetheless, AMPs have also been used more recently in other settings such as molecular probes grafted on biosensors able to detect whole bacteria. Rapid, reliable and cost-efficient diagnostic tools for bacterial infection could prevent the spread of the pathogen from the earliest stages. Biosensors based on AMPs would enable easy monitoring of potentially infected samples, thanks to their powerful versatility and integrability in pre-existent settings. AMPs, which show a broad spectrum of interactions with bacterial membranes, can be tailored in order to design ubiquitous biosensors easily adaptable to clinical settings. This review aims to focus on the state of the art of AMPs used as the recognition elements of whole bacteria in label-free biosensors with a particular focus on the characteristics obtained in terms of threshold, volume of sample analysable and medium, in order to assess their workability in real-world applications.

scholarly journals Antimicrobial Peptides: Mechanisms of Action and Resistance

2016 ◽  
Vol 96 (3) ◽  
pp. 254-260 ◽  
Author(s):  
B. Bechinger ◽  
S.-U. Gorr
Keyword(s):  
Cell Wall ◽  
Cell Membrane ◽  
Antimicrobial Peptides ◽  
Bacterial Resistance ◽  
Rare Event ◽  
Mechanisms Of Action ◽  
Current Evidence ◽  
Aggregation State ◽  
Host Defense Peptides ◽  
Bacterial Membranes

More than 40 antimicrobial peptides and proteins (AMPs) are expressed in the oral cavity. These AMPs have been organized into 6 functional groups, 1 of which, cationic AMPs, has received extensive attention in recent years for their promise as potential antibiotics. The goal of this review is to describe recent advances in our understanding of the diverse mechanisms of action of cationic AMPs and the bacterial resistance against these peptides. The recently developed peptide GL13K is used as an example to illustrate many of the discussed concepts. Cationic AMPs typically exhibit an amphipathic conformation, which allows increased interaction with negatively charged bacterial membranes. Peptides undergo changes in conformation and aggregation state in the presence of membranes; conversely, lipid conformation and packing can adapt to the presence of peptides. As a consequence, a single peptide can act through several mechanisms depending on the peptide’s structure, the peptide:lipid ratio, and the properties of the lipid membrane. Accumulating evidence shows that in addition to acting at the cell membrane, AMPs may act on the cell wall, inhibit protein folding or enzyme activity, or act intracellularly. Therefore, once a peptide has reached the cell wall, cell membrane, or its internal target, the difference in mechanism of action on gram-negative and gram-positive bacteria may be less pronounced than formerly assumed. While AMPs should not cause widespread resistance due to their preferential attack on the cell membrane, in cases where specific protein targets are involved, the possibility exists for genetic mutations and bacterial resistance. Indeed, the potential clinical use of AMPs has raised the concern that resistance to therapeutic AMPs could be associated with resistance to endogenous host-defense peptides. Current evidence suggests that this is a rare event that can be overcome by subtle structural modifications of an AMP.

Understanding membrane-active antimicrobial peptides

2017 ◽  
Vol 50 ◽  
Author(s):  
Huey W. Huang ◽  
Nicholas E. Charron
Keyword(s):  
Antimicrobial Peptides ◽  
Soft Matter ◽  
Structural Changes ◽  
Molecular Mechanisms ◽  
Bacterial Resistance ◽  
Antimicrobial Agents ◽  
Molecular Structures ◽  
Membrane Domain ◽  
Defense Proteins ◽  
Bacterial Membranes

AbstractBacterial membranes represent an attractive target for the design of new antibiotics to combat widespread bacterial resistance to traditional inhibitor-based antibiotics. Understanding how antimicrobial peptides (AMPs) and other membrane-active agents attack membranes could facilitate the design of new, effective antimicrobials. AMPs, which are small, gene-encoded host defense proteins, offer a promising basis for the study of membrane-active antimicrobial agents. These peptides are cationic and amphipathic, spontaneously binding to bacterial membranes and inducing transmembrane permeability to small molecules. Yet there are often confusions surrounding the details of the molecular mechanisms of AMPs. Following the doctrine of structure–function relationship, AMPs are often viewed as the molecular scaffolding of pores in membranes. Instead we believe that the full mechanism of AMPs is understandable if we consider the interactions of AMPs with the whole membrane domain, where interactions induce structural transformations of the entire membrane, rather than forming localized molecular structures. We believe that it is necessary to consider the entire soft matter peptide-membrane system as it evolves through several distinct states. Accordingly, we have developed experimental techniques to investigate the state and structure of the membrane as a function of the bound peptide to lipid ratio, exactly as AMPs in solution progressively bind to the membrane and induce structural changes to the entire system. The results from these studies suggest that global interactions of AMPs with the membrane domain are of fundamental importance to understanding the antimicrobial mechanisms of AMPs.

scholarly journals In-cell Solid-State NMR Studies of Antimicrobial Peptides

2020 ◽  
Vol 2 ◽  
Author(s):  
Frances Separovic ◽  
David W. Keizer ◽  
Marc-Antoine Sani
Keyword(s):  
Solid State ◽  
Antimicrobial Peptides ◽  
Solid State Nmr ◽  
Bacterial Resistance ◽  
Invasive Technique ◽  
Nmr Studies ◽  
Bacterial Membranes ◽  
Modes Of Action

Antimicrobial peptides (AMPs) have attracted attention as alternatives to classic antibiotics due to their expected limited pressure on bacterial resistance mechanisms. Yet, their modes of action, in particular in vivo, remain to be elucidated. In situ atomistic-scale details of complex biomolecular assemblies is a challenging requirement for deciphering the complex modes of action of AMPs. The large diversity of molecules that modulate complex interactions limits the resolution achievable using imaging methodology. Herein, the latest advances in in-cell solid-state NMR (ssNMR) are discussed, which demonstrate the power of this non-invasive technique to provide atomic details of molecular structure and dynamics. Practical requirements for investigations of intact bacteria are discussed. An overview of recent in situ NMR investigations of the architecture and metabolism of bacteria and the effect of AMPs on various bacterial structures is presented. In-cell ssNMR revealed that the studied AMPs have a disruptive action on the molecular packing of bacterial membranes and DNA. Despite the limited number of studies, in-cell ssNMR is emerging as a powerful technique to monitor in situ the interplay between bacteria and AMPs.

scholarly journals Capsule Polysaccharide Mediates Bacterial Resistance to Antimicrobial Peptides

2004 ◽  
Vol 72 (12) ◽  
pp. 7107-7114 ◽  
Author(s):  
Miguel A. Campos ◽  
Miguel A. Vargas ◽  
Verónica Regueiro ◽  
Catalina M. Llompart ◽  
Sebastián Albertí ◽  
...  
Keyword(s):  
Antimicrobial Peptides ◽  
Bacterial Resistance ◽  
Wild Type Strain ◽  
Critical Role ◽  
Polymyxin B ◽  
Innate Immune ◽  
Wild Type ◽  
Bacterial Membranes ◽  
O Antigen

ABSTRACT The innate immune system plays a critical role in the defense of areas exposed to microorganisms. There is an increasing body of evidence indicating that antimicrobial peptides and proteins (APs) are one of the most important weapons of this system and that they make up the protective front for the respiratory tract. On the other hand, it is known that pathogenic organisms have developed countermeasures to resist these agents such as reducing the net negative charge of the bacterial membranes. Here we report the characterization of a novel mechanism of resistance to APs that is dependent on the bacterial capsule polysaccharide (CPS). Klebsiella pneumoniae CPS mutant was more sensitive than the wild type to human neutrophil defensin 1, β-defensin 1, lactoferrin, protamine sulfate, and polymyxin B. K. pneumoniae lipopolysaccharide O antigen did not play an important role in AP resistance, and CPS was the only factor conferring protection against polymyxin B in strains lacking O antigen. In addition, we found a significant correlation between the amount of CPS expressed by a given strain and the resistance to polymyxin B. We also showed that K. pneumoniae CPS mutant bound more polymyxin B than the wild-type strain with a concomitant increased in the self-promoted pathway. Taken together, our results suggest that CPS protects bacteria by limiting the interaction of APs with the surface. Finally, we report that K. pneumoniae increased the amount of CPS and upregulated cps transcription when grown in the presence of polymyxin B and lactoferrin.

scholarly journals Highlights on the alternatives to antibiotic therapy against bacterial infection

2021 ◽  
Vol 11 (2) ◽  
pp. 194-203
Author(s):  
Bijayanta Sircar ◽  
Shyamapada Mandal
Keyword(s):  
Antimicrobial Peptides ◽  
Pathogenic Bacteria ◽  
Bacterial Resistance ◽  
Scientific Data ◽  
New Drugs ◽  
Health Concern ◽  
Antibiotic Resistant ◽  
Effective Drugs ◽  
Emergence Of Resistance ◽  
Antibacterial Capacity

The antibiotic resistance among gram-positive and gram-negative pathogenic bacteria is of global health concern. This has prompted the development of new effective drugs. But the discovery and development of new drugs is slow, and the emergence of resistance to such new drugs, on the other hand, is rapid as well as continuous among the bacteria. Therefore, in tackling the emergence of antibiotic resistant pathogenic bacteria finding alternative ways is vital. This communication, based on the published scientific data, summarizes the antibacterial capacity of some naturally derived agents such as honey, phytocomponents, probiotics, and antimicrobial peptides that might bring new essence in biomedicine.  Keywords: Bacterial resistance, alternative therapeutics, honey, phytomedicine, probiotics, antimicrobial peptides.

scholarly journals Challenge in the Discovery of New Drugs: Antimicrobial Peptides against WHO-List of Critical and High-Priority Bacteria

Pharmaceutics ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 773
Author(s):  
Cesar Augusto Roque-Borda ◽  
Patricia Bento da Silva ◽  
Mosar Corrêa Rodrigues ◽  
Ricardo Bentes Azevedo ◽  
Leonardo Di Filippo ◽  
...  
Keyword(s):  
Antimicrobial Peptides ◽  
Conventional Treatment ◽  
Bacterial Resistance ◽  
Resistance Mechanisms ◽  
New Drugs ◽  
Resistant Bacteria ◽  
Multiple Resistance ◽  
Clinical Use ◽  
Bacterial Strains ◽  
Bacterial Cell Membrane

Bacterial resistance has intensified in recent years due to the uncontrolled use of conventional drugs, and new bacterial strains with multiple resistance have been reported. This problem may be solved by using antimicrobial peptides (AMPs), which fulfill their bactericidal activity without developing much bacterial resistance. The rapid interaction between AMPs and the bacterial cell membrane means that the bacteria cannot easily develop resistance mechanisms. In addition, various drugs for clinical use have lost their effect as a conventional treatment; however, the synergistic effect of AMPs with these drugs would help to reactivate and enhance antimicrobial activity. Their efficiency against multi-resistant and extensively resistant bacteria has positioned them as promising molecules to replace or improve conventional drugs. In this review, we examined the importance of antimicrobial peptides and their successful activity against critical and high-priority bacteria published in the WHO list.

Antimicrobial peptides for the treatment of pulmonary tuberculosis, allies or foes?

2018 ◽  
Vol 24 (10) ◽  
pp. 1138-1147
Author(s):  
Bruno Rivas-Santiago ◽  
Flor Torres-Juarez
Keyword(s):  
Pulmonary Tuberculosis ◽  
Antimicrobial Peptides ◽  
Experimental Models ◽  
New Drugs ◽  
World Health ◽  
Public Health Issue ◽  
Health Organization ◽  
Drug Resistant Strains

Tuberculosis is an ancient disease that has become a serious public health issue in recent years, although increasing incidence has been controlled, deaths caused by Mycobacterium tuberculosis have been accentuated due to the emerging of multi-drug resistant strains and the comorbidity with diabetes mellitus and HIV. This situation is threatening the goals of World Health Organization (WHO) to eradicate tuberculosis in 2035. WHO has called for the creation of new drugs as an alternative for the treatment of pulmonary tuberculosis, among the plausible molecules that can be used are the Antimicrobial Peptides (AMPs). These peptides have demonstrated remarkable efficacy to kill mycobacteria in vitro and in vivo in experimental models, nevertheless, these peptides not only have antimicrobial activity but also have a wide variety of functions such as angiogenesis, wound healing, immunomodulation and other well-described roles into the human physiology. Therapeutic strategies for tuberculosis using AMPs must be well thought prior to their clinical use; evaluating comorbidities, family history and risk factors to other diseases, since the wide function of AMPs, they could lead to collateral undesirable effects.

Antimicrobial Peptides and their Multiple Effects at Sub-Inhibitory Concentrations

2020 ◽  
Vol 20 (14) ◽  
pp. 1264-1273 ◽  
Author(s):  
Bruno Casciaro ◽  
Floriana Cappiello ◽  
Walter Verrusio ◽  
Mauro Cacciafesta ◽  
Maria Luisa Mangoni
Keyword(s):  
Antimicrobial Peptides ◽  
Inhibitory Concentration ◽  
Multidrug Resistant ◽  
Mechanisms Of Action ◽  
New Drugs ◽  
Lead Compounds ◽  
Bacterial Pathogenicity ◽  
Growth Inhibitory ◽  
Resistant Strains ◽  
Conventional Antibiotics

The frequent occurrence of multidrug-resistant strains to conventional antimicrobials has led to a clear decline in antibiotic therapies. Therefore, new molecules with different mechanisms of action are extremely necessary. Due to their unique properties, antimicrobial peptides (AMPs) represent a valid alternative to conventional antibiotics and many of them have been characterized for their activity and cytotoxicity. However, the effects that these peptides cause at concentrations below the minimum growth inhibitory concentration (MIC) have yet to be fully analyzed along with the underlying molecular mechanism. In this mini-review, the ability of AMPs to synergize with different antibiotic classes or different natural compounds is examined. Furthermore, data on microbial resistance induction are reported to highlight the importance of antibiotic resistance in the fight against infections. Finally, the effects that sub-MIC levels of AMPs can have on the bacterial pathogenicity are summarized while showing how signaling pathways can be valid therapeutic targets for the treatment of infectious diseases. All these aspects support the high potential of AMPs as lead compounds for the development of new drugs with antibacterial and immunomodulatory activities.

scholarly journals In Vitro Spectroscopy-Based Profiling of Urothelial Carcinoma: A Fourier Transform Infrared and Raman Imaging Study

Cancers ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 123
Author(s):  
Monika Kujdowicz ◽  
Wojciech Placha ◽  
Brygida Mech ◽  
Karolina Chrabaszcz ◽  
Krzysztof Okoń ◽  
...  
Keyword(s):  
Bladder Cancer ◽  
Fourier Transform ◽  
Cancer Cells ◽  
Cell Line ◽  
Cell Lines ◽  
Malignant Neoplasm ◽  
Fourier Transform Infrared ◽  
Diagnostic Tools ◽  
Label Free ◽  
Bladder Cancer Cells

Markers of bladder cancer cells remain elusive, which is a major cause of the low recognition of this malignant neoplasm and its recurrence. This implies an urgent need for additional diagnostic tools which are based on the identification of the chemism of bladder cancer. In this study, we employed label-free techniques of molecular imaging—Fourier Transform Infrared and Raman spectroscopic imaging—to investigate bladder cancer cell lines of various invasiveness (T24a, T24p, HT-1376, and J82). The urothelial HCV-29 cell line was the healthy control. Specific biomolecules discriminated spatial distribution of the nucleus and cytoplasm and indicated the presence of lipid bodies and graininess in some cell lines. The most prominent discriminators are the total content of lipids and sugar moieties as well as the presence of glycogen and other carbohydrates, un/saturated lipids, cytochromes, and a level of S-S bridges in proteins. The combination of the obtained hyperspectral database and chemometric methods showed a clear differentiation of each cell line at the level of the nuclei and cytoplasm and pointed out spectral signals which differentiated bladder cancer cells. Registered spectral markers correlated with biochemical composition changes can be associated with pathogenesis and potentially used for the diagnosis of bladder cancer and response to experimental therapies.

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