scholarly journals Rational Designed Hybrid Peptides Show up to a 6-fold Increase in Antimicrobial Activity and Demonstrate Different Ultrastructural Changes as the Parental Peptides measured by BioSAXS

2021 ◽  
Author(s):  
Kai Hilpert ◽  
Jurnorain Gani ◽  
Christoph Rumancev ◽  
Nathan Simpson ◽  
Paula Matilde Lopez-Perez ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Antimicrobial Peptides ◽  
Fold Increase ◽  
Ultrastructural Changes ◽  
Therapeutic Window ◽  
Resistant Bacteria ◽  
Haemolytic Activity ◽  
Hybrid Peptide ◽  
E Coli ◽  
Hybrid Peptides

Antimicrobial peptides (AMPs) are a promising class of compounds being developed against multi-drug resistant bacteria. Hybridization has been reported to increase antimicrobial activity. Here, two proline-rich peptides (consP1: VRKPPYLPRPRPRPL-CONH2 and Bac5-v291: RWRRPIRRRPIRPPFWR-CONH2) were combined with two arginine-isoleucine-rich peptides (optP1: KIILRIRWR-CONH2 and optP7: KRRVRWIIW-CONH2). Proline-rich antimicrobial peptides (PrAMPs) are known to inhibit the bacterial ribosome, shown also for Bac5-v291, whereas it is hypothesized a dirty drug model for the arginine-isoleucine-rich peptides. That hypothesis was underpinned by transmission electron microscopy and biological small-angle X-ray scattering (BioSAXS). The hybrid peptides showed a stronger antimicrobial activity compared to the proline-rich peptides, except when compared to Bac5-v291 against E. coli. The increase in activity compared to the arginine-isoleucine-rich peptides was up to 6-fold, however, it was not a general increase but was dependent on the combination of peptides and bacteria. BioSAXS experiments revealed that proline-rich peptides and arginine-isoleucine-rich peptides induce very different ultrastructural changes in E. coli, whereas a hybrid peptide (hyP7B5GK) shows changes, different to both parental peptides and the untreated control. These different ultrastructural changes indicated that the mode of action of the parental peptides is different from each other as well as from the hybrid peptide hyP7B5GK. All peptides showed very low haemolytic activity, some of them showed a 100-fold or larger therapeutic window, demonstrating the potential for further drug development.

scholarly journals Rational Designed Hybrid Peptides Show up to a 6-Fold Increase in Antimicrobial Activity and Demonstrate Different Ultrastructural Changes as the Parental Peptides Measured by BioSAXS

2021 ◽  
Vol 12 ◽  
Author(s):  
Kai Hilpert ◽  
Jurnorain Gani ◽  
Christoph Rumancev ◽  
Nathan Simpson ◽  
Paula Matilde Lopez-Perez ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Antimicrobial Peptides ◽  
Fold Increase ◽  
Ultrastructural Changes ◽  
Therapeutic Window ◽  
Resistant Bacteria ◽  
Haemolytic Activity ◽  
Hybrid Peptide ◽  
E Coli ◽  
Hybrid Peptides

Antimicrobial peptides (AMPs) are a promising class of compounds being developed against multi-drug resistant bacteria. Hybridization has been reported to increase antimicrobial activity. Here, two proline-rich peptides (consP1: VRKPPYLPRPRPRPL-CONH2 and Bac5-v291: RWRRPIRRRPIRPPFWR-CONH2) were combined with two arginine-isoleucine-rich peptides (optP1: KIILRIRWR-CONH2 and optP7: KRRVRWIIW-CONH2). Proline-rich antimicrobial peptides (PrAMPs) are known to inhibit the bacterial ribosome, shown also for Bac5-v291, whereas it is hypothesized a “dirty drug” model for the arginine-isoleucine-rich peptides. That hypothesis was underpinned by transmission electron microscopy and biological small-angle X-ray scattering (BioSAXS). The strength of BioSAXS is the power to detect ultrastructural changes in millions of cells in a short time (seconds) in a high-throughput manner. This information can be used to classify antimicrobial compounds into groups according to the ultrastructural changes they inflict on bacteria and how the bacteria react towards that assault. Based on previous studies, this correlates very well with different modes of action. Due to the novelty of this approach direct identification of the target of the antimicrobial compound is not yet fully established, more research is needed. More research is needed to address this limitation. The hybrid peptides showed a stronger antimicrobial activity compared to the proline-rich peptides, except when compared to Bac5-v291 against E. coli. The increase in activity compared to the arginine-isoleucine-rich peptides was up to 6-fold, however, it was not a general increase but was dependent on the combination of peptides and bacteria. BioSAXS experiments revealed that proline-rich peptides and arginine-isoleucine-rich peptides induce very different ultrastructural changes in E. coli, whereas a hybrid peptide (hyP7B5GK) shows changes, different to both parental peptides and the untreated control. These different ultrastructural changes indicated that the mode of action of the parental peptides might be different from each other as well as from the hybrid peptide hyP7B5GK. All peptides showed very low haemolytic activity, some of them showed a 100-fold or larger therapeutic window, demonstrating the potential for further drug development.

scholarly journals Halogenation as a tool to tune antimicrobial activity of peptoids

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Natalia Molchanova ◽  
Josefine Eilsø Nielsen ◽  
Kristian B. Sørensen ◽  
Bala Krishna Prabhala ◽  
Paul Robert Hansen ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Self Assembly ◽  
Therapeutic Potential ◽  
Fold Increase ◽  
Resistant Bacteria ◽  
Clear Correlation ◽  
E Coli ◽  
Drug Resistant Bacteria ◽  
Phenyl Rings ◽  
Proteolytic Stability

Abstract Antimicrobial peptides have attracted considerable interest as potential new class of antibiotics against multi-drug resistant bacteria. However, their therapeutic potential is limited, in part due to susceptibility towards enzymatic degradation and low bioavailability. Peptoids (oligomers of N-substituted glycines) demonstrate proteolytic stability and better bioavailability than corresponding peptides while in many cases retaining antibacterial activity. In this study, we synthesized a library of 36 peptoids containing fluorine, chlorine, bromine and iodine atoms, which vary by length and level of halogen substitution in position 4 of the phenyl rings. As we observed a clear correlation between halogenation of an inactive model peptoid and its increased antimicrobial activity, we designed chlorinated and brominated analogues of a known peptoid and its shorter counterpart. Short brominated analogues displayed up to 32-fold increase of the activity against S. aureus and 16- to 64-fold against E. coli and P. aeruginosa alongside reduced cytotoxicity. The biological effect of halogens seems to be linked to the relative hydrophobicity and self-assembly properties of the compounds. By small angle X-ray scattering (SAXS) we have demontrated how the self-assembled structures are dependent on the size of the halogen, degree of substitution and length of the peptoid, and correlated these features to their activity.

scholarly journals Protein-Engineered Polymers Functionalized with Antimicrobial Peptides for the Development of Active Surfaces

2021 ◽  
Vol 11 (12) ◽  
pp. 5352
Author(s):  
Ana Margarida Pereira ◽  
Diana Gomes ◽  
André da Costa ◽  
Simoni Campos Dias ◽  
Margarida Casal ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Antimicrobial Peptides ◽  
Recombinant Dna ◽  
Biological Properties ◽  
Resistant Bacteria ◽  
Recombinant Dna Technology ◽  
Free Standing ◽  
Microbial Cell Factories ◽  
Cell Factories ◽  
Antimicrobial Materials

Antibacterial resistance is a major worldwide threat due to the increasing number of infections caused by antibiotic-resistant bacteria with medical devices being a major source of these infections. This suggests the need for new antimicrobial biomaterial designs able to withstand the increasing pressure of antimicrobial resistance. Recombinant protein polymers (rPPs) are an emerging class of nature-inspired biopolymers with unique chemical, physical and biological properties. These polymers can be functionalized with antimicrobial molecules utilizing recombinant DNA technology and then produced in microbial cell factories. In this work, we report the functionalization of rPBPs based on elastin and silk-elastin with different antimicrobial peptides (AMPs). These polymers were produced in Escherichia coli, successfully purified by employing non-chromatographic processes, and used for the production of free-standing films. The antimicrobial activity of the materials was evaluated against Gram-positive and Gram-negative bacteria, and results showed that the polymers demonstrated antimicrobial activity, pointing out the potential of these biopolymers for the development of new advanced antimicrobial materials.

Antimicrobial activity and biofilm inhibition of riparins I, II and III and ultrastructural changes in multidrug-resistant bacteria of medical importance

2020 ◽  
Vol 149 ◽  
pp. 104529
Author(s):  
Jorge Belém Oliveira-Júnior ◽  
Everton Morais da Silva ◽  
Dyana Leal Veras ◽  
Karla Raíza Cardoso Ribeiro ◽  
Catarina Fernandes de Freitas ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Multidrug Resistant ◽  
Ultrastructural Changes ◽  
Resistant Bacteria ◽  
Multidrug Resistant Bacteria ◽  
Biofilm Inhibition ◽  
Medical Importance

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 Human MAIT cell cytolytic effector proteins synergize to overcome carbapenem resistance in Escherichia coli

2020 ◽  
Author(s):  
Caroline Boulouis ◽  
Wan Rong Sia ◽  
Muhammad Yaaseen Gulam ◽  
Jocelyn Qi Min Teo ◽  
Thanh Kha Phan ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Activity ◽  
Bactericidal Activity ◽  
Granzyme B ◽  
Carbapenem Resistance ◽  
Effector Proteins ◽  
Resistant Bacteria ◽  
E Coli ◽  
Mait Cells ◽  
Mait Cell

AbstractMucosa-associated invariant T (MAIT) cells are abundant antimicrobial T cells in humans, and recognize antigens derived from the microbial riboflavin biosynthetic pathway presented by the MHC-Ib-related protein (MR1). However, the mechanisms responsible for MAIT cell antimicrobial activity are not fully understood, and the efficacy of these mechanisms against antibiotic resistant bacteria has not been explored. Here, we show that MAIT cells mediate MR1-restricted antimicrobial activity against E. coli clinical strains in a manner dependent on the activity of cytolytic proteins, but independent of production of pro-inflammatory cytokines or induction of apoptosis in infected cells. The combined action of the pore-forming antimicrobial protein granulysin and the serine protease granzyme B released in response to TCR-mediated recognition of MR1-presented antigen is essential to mediate control against both cell-associated and free-living E. coli. Furthermore, MAIT cell-mediated bacterial control extend to multidrug-resistant E. coli primary clinical isolates additionally resistant to carbapenems, a class of last resort antibiotics. Notably, high levels of granulysin and granzyme B in the MAIT cell secretomes directly damage bacterial cells by increasing their permeability, rendering initially resistant E. coli susceptible to the bactericidal activity of carbapenems. These findings define the role of cytolytic effector proteins in MAIT cell-mediated antimicrobial activity, and indicate that granulysin and granzyme B synergize to restore carbapenem bactericidal activity and overcome carbapenem resistance in E. coli.One Sentence SummaryPotent antimicrobial activity of human MAIT cells overcomes carbapenem-resistance in control of Escherichia coli

scholarly journals Purification and biological activity of natural variants synthesized by tridecaptin M gene cluster and in vitro drug-kinetics of this antibiotic class

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Manoj Jangra ◽  
Manpreet Kaur ◽  
Mansi Podia ◽  
Rushikesh Tambat ◽  
Vidhu Singh ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Gene Cluster ◽  
Resistant Bacteria ◽  
Haemolytic Activity ◽  
M Gene ◽  
High Density Culture ◽  
Antibiotic Effect ◽  
Natural Variants ◽  
Drug Kinetics

AbstractThe flexibility of the adenylation domains of non-ribosomal peptide synthetases (NRPSs) to different substrates creates a diversity of structurally similar peptides. In the present study, we investigated the antimicrobial activity of different natural variants synthesized by tridecaptin M gene cluster and performed the in vitro drug kinetics on this class. The natural variants were isolated and characterized using MALDI-MS and tandem mass spectrometry. All the peptides were studied for their antimicrobial activity in different pathogens, including colistin-resistant bacteria, and for haemolytic activity. Furthermore, in vitro drug kinetics was performed with tridecaptin M (or M1, the major product of the gene cluster). The natural variants displayed a varying degree of bioactivity with M11 showing the most potent antibacterial activity (MIC, 1–8 µg/ml), even against A. baumannii and P. aeruginosa strains. The in vitro kinetic studies revealed that tridecaptin M at a concentration of 16 µg/ml eradicated the bacteria completely in high-density culture. The compound demonstrated desirable post-antibiotic effect after two-hour exposure at MIC concentration. We also observed the reversal of resistance to this class of antibiotics in the presence of carbonyl cyanide m-chlorophenyl hydrazine (CCCP). Altogether, the study demonstrated that tridecaptins are an excellent drug candidate against drug-resistant Gram-negative bacteria. Future studies are required to design a superior tridecaptin by investigating the interactions of different natural variants with the target.

scholarly journals Damage of the Bacterial Cell Envelope by Antimicrobial Peptides Gramicidin S and PGLa as Revealed by Transmission and Scanning Electron Microscopy

2010 ◽  
Vol 54 (8) ◽  
pp. 3132-3142 ◽  
Author(s):  
Mareike Hartmann ◽  
Marina Berditsch ◽  
Jacques Hawecker ◽  
Mohammad Fotouhi Ardakani ◽  
Dagmar Gerthsen ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Antimicrobial Peptides ◽  
Lipid Membrane ◽  
Ultrastructural Changes ◽  
Morphological Alterations ◽  
Bacterial Membranes ◽  
E Coli ◽  
Gramicidin S ◽  
Scanning Electron

ABSTRACT Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to examine the ultrastructural changes in bacteria induced by antimicrobial peptides (AMPs). Both the β-stranded gramicidin S and the α-helical peptidyl-glycylleucine-carboxyamide (PGLa) are cationic amphiphilic AMPs known to interact with bacterial membranes. One representative Gram-negative strain, Escherichia coli ATCC 25922, and one representative Gram-positive strain, Staphylococcus aureus ATCC 25923, were exposed to the AMPs at sub-MICs and supra-MICs in salt-free medium. SEM revealed a shortening and swelling of the E. coli cells, and multiple blisters and bubbles formed on their surface. The S. aureus cells seemed to burst upon AMP exposure, showing open holes and deep craters in their envelope. TEM revealed the formation of intracellular membranous structures in both strains, which is attributed to a lateral expansion of the lipid membrane upon peptide insertion. Also, some morphological alterations in the DNA region were detected for S. aureus. After E. coli was incubated with AMPs in medium with low ionic strength, the cells appeared highly turgid compared to untreated controls. This observation suggests that the AMPs enhance osmosis through the inner membrane, before they eventually cause excessive leakage of the cellular contents. The adverse effect on the osmoregulatory capacity of the bacteria is attributed to the membrane-permeabilizing action of the amphiphilic peptides, even at low (sub-MIC) AMP concentrations. Altogether, the results demonstrate that both TEM and SEM, as well as appropriate sample preparation protocols, are needed to obtain detailed mechanistic insights into peptide function.

scholarly journals Nanostructured Antimicrobial Peptides: Crucial Steps of Overcoming the Bottleneck for Clinics

2021 ◽  
Vol 12 ◽  
Author(s):  
Zhanyi Yang ◽  
Shiqi He ◽  
Hua Wu ◽  
Ting Yin ◽  
Lili Wang ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Controlled Release ◽  
Antimicrobial Peptides ◽  
Biological Activities ◽  
Antimicrobial Properties ◽  
Multidrug Resistant ◽  
Great Promise ◽  
Resistant Bacteria ◽  
Biological Stability ◽  
Security Issue

The security issue of human health is faced with dispiriting threats from multidrug-resistant bacteria infections induced by the abuse and misuse of antibiotics. Over decades, the antimicrobial peptides (AMPs) hold great promise as a viable alternative to treatment with antibiotics due to their peculiar antimicrobial mechanisms of action, broad-spectrum antimicrobial activity, lower drug residue, and ease of synthesis and modification. However, they universally express a series of disadvantages that hinder their potential application in the biomedical field (e.g., low bioavailability, poor protease resistance, and high cytotoxicity) and extremely waste the abundant resources of AMP database discovered over the decades. For all these reasons, the nanostructured antimicrobial peptides (Ns-AMPs), based on a variety of nanosystem modification, have made up for the deficiencies and pushed the development of novel AMP-based antimicrobial therapies. In this review, we provide an overview of the advantages of Ns-AMPs in improving therapeutic efficacy and biological stability, reducing side effects, and gaining the effect of organic targeting and drug controlled release. Then the different material categories of Ns-AMPs are described, including inorganic material nanosystems containing AMPs, organic material nanosystems containing AMPs, and self-assembled AMPs. Additionally, this review focuses on the Ns-AMPs for the effect of biological activities, with emphasis on antimicrobial activity, biosecurity, and biological stability. The “state-of-the-art” antimicrobial modes of Ns-AMPs, including controlled release of AMPs under a specific environment or intrinsic antimicrobial properties of Ns-AMPs, are also explicated. Finally, the perspectives and conclusions of the current research in this field are also summarized.

scholarly journals Evaluation of Antimicrobial Activity of Buforin I and Nisin and the Synergistic Effect of Their Combination as a Novel Antimicrobial Preservative

2020 ◽  
Vol 83 (11) ◽  
pp. 2018-2025 ◽  
Author(s):  
SAHAR ROSHANAK ◽  
FAKHRI SHAHIDI ◽  
FARIDEH TABATABAEI YAZDI ◽  
ALI JAVADMANESH ◽  
JEBRAEIL MOVAFFAGH
Keyword(s):  
Antimicrobial Activity ◽  
Synergistic Effect ◽  
Antimicrobial Peptides ◽  
Antimicrobial Agents ◽  
Antimicrobial Properties ◽  
Food Spoilage ◽  
Food Preservatives ◽  
Minimum Fungicidal Concentration ◽  
E Coli ◽  
Spoilage Microorganisms

ABSTRACT One of the most effective methods for increasing the antimicrobial activity of a substance is to combine it with one or more other antimicrobial agents. The aim of the present study was to evaluate the antimicrobial effect of buforin I and nisin alone and investigate the synergistic action of these compounds against the most important food spoilage microorganisms, including Bacillus subtilis, Staphylococcus epidermidis, Listeria innocua, Escherichia coli, Salmonella serovar Enteritidis, Aspergillus oryzae, Rhodotorula glutinis, and Geotrichum candidum. The results of MIC and MBC or minimum fungicidal concentration examinations showed that buforin I had higher antimicrobial activity than nisin on all microbial strains used in this study (P ≤ 0.5). E. coli was the most resistant to both antimicrobial agents, whereas L. innocua and S. epidermidis were the most sensitive to nisin and buforin I, respectively. The results of synergistic interaction between buforin I and nisin indicated that the combination of buforin I and nisin on B. subtilis, S. epidermidis, and A. oryzae showed a synergistic effect, whereas it had no effect on Salmonella serovar Enteritidis and G. candidum. The combination of buforin I and nisin showed a partial synergistic effect on L. innocua, E. coli, and R. glutinis. Assessment of viability of the microorganisms under the antimicrobial agents alone and in combination with each other at MICs and fraction inhibitory concentrations indicated that use of these antimicrobial agents in combination enhances antimicrobial activity at lower concentrations of both agents. The present study investigated the antimicrobial properties of buforin I against food spoilage microorganisms for the first time and suggests that its use alone or with nisin may provide a clear horizon for the application of antimicrobial peptides as natural preservatives. Thus, the combination of antimicrobial peptides and traditional antimicrobial food preservatives could be a promising option for the prevention of contamination, spoilage, and infestation of food and beverage products. HIGHLIGHTS

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