Antimicrobial Peptides—or How Our Ancestors Learned to Control the Microbiome

mBio ◽

10.1128/mbio.01847-21 ◽

2021 ◽

Author(s):

Thomas C. G. Bosch ◽

Michael Zasloff

Keyword(s):

Innate Immunity ◽

Antimicrobial Peptides ◽

Life Forms ◽

Gram Positive ◽

Enveloped Viruses ◽

Fundamental Component ◽

Wide Range ◽

Charged Peptides ◽

Positively Charged

Antimicrobial peptides (AMPs) are short and generally positively charged peptides found in a wide variety of life forms from microorganisms to humans. Their wide range of activity against pathogens, including Gram-positive and -negative bacteria, yeasts, fungi, and enveloped viruses makes them a fundamental component of innate immunity.

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Antibacterial Peptides

Antibiotics ◽

10.3390/antibiotics9040142 ◽

2020 ◽

Vol 9 (4) ◽

pp. 142

Author(s):

Jean-Marc Sabatier

Keyword(s):

Antimicrobial Peptides ◽

Host Defense ◽

Life Forms ◽

Natural Host ◽

Gram Negative Bacteria ◽

Antibacterial Peptides ◽

Chemotherapeutic Drugs ◽

Gram Positive ◽

Defense Compounds ◽

Gram Negative

As natural host defense compounds produced by numerous prokaryotic and eukaryotic life forms, antimicrobial peptides (AMPs) are now emerging as solid candidate chemotherapeutic drugs to fight against the various types of pathogenic Gram-positive and Gram-negative bacteria, especially those resistant to current antibiotics [...]

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Characterization and identification of antimicrobial peptides with different functional activities

Briefings in Bioinformatics ◽

10.1093/bib/bbz043 ◽

2019 ◽

Vol 21 (3) ◽

pp. 1098-1114 ◽

Cited By ~ 8

Author(s):

Chia-Ru Chung ◽

Ting-Rung Kuo ◽

Li-Ching Wu ◽

Tzong-Yi Lee ◽

Jorng-Tzong Horng

Keyword(s):

Antimicrobial Peptides ◽

Hot Spot ◽

Gram Negative Bacteria ◽

Gram Positive ◽

Van Der Waals Volume ◽

Gram Negative ◽

Functional Activities ◽

Wide Range ◽

Anti Cancer ◽

Anti Fungal

Abstract In recent years, antimicrobial peptides (AMPs) have become an emerging area of focus when developing therapeutics hot spot residues of proteins are dominant against infections. Importantly, AMPs are produced by virtually all known living organisms and are able to target a wide range of pathogenic microorganisms, including viruses, parasites, bacteria and fungi. Although several studies have proposed different machine learning methods to predict peptides as being AMPs, most do not consider the diversity of AMP activities. On this basis, we specifically investigated the sequence features of AMPs with a range of functional activities, including anti-parasitic, anti-viral, anti-cancer and anti-fungal activities and those that target mammals, Gram-positive and Gram-negative bacteria. A new scheme is proposed to systematically characterize and identify AMPs and their functional activities. The 1st stage of the proposed approach is to identify the AMPs, while the 2nd involves further characterization of their functional activities. Sequential forward selection was employed to extract potentially informative features that are possibly associated with the functional activities of the AMPs. These features include hydrophobicity, the normalized van der Waals volume, polarity, charge and solvent accessibility—all of which are essential attributes in classifying between AMPs and non-AMPs. The results revealed the 1st stage AMP classifier was able to achieve an area under the receiver operating characteristic curve (AUC) value of 0.9894. During the 2nd stage, we found pseudo amino acid composition to be an informative attribute when differentiating between AMPs in terms of their functional activities. The independent testing results demonstrated that the AUCs of the multi-class models were 0.7773, 0.9404, 0.8231, 0.8578, 0.8648, 0.8745 and 0.8672 for anti-parasitic, anti-viral, anti-cancer, anti-fungal AMPs and those that target mammals, Gram-positive and Gram-negative bacteria, respectively. The proposed scheme helps facilitate biological experiments related to the functional analysis of AMPs. Additionally, it was implemented as a user-friendly web server (AMPfun, http://fdblab.csie.ncu.edu.tw/AMPfun/index.html) that allows individuals to explore the antimicrobial functions of peptides of interest.

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Defensins and cathelicidins in inflammatory lung disease: beyond antimicrobial activity

Biochemical Society Transactions ◽

10.1042/bst0340276 ◽

2006 ◽

Vol 34 (2) ◽

pp. 276-278 ◽

Cited By ~ 16

Author(s):

P.S. Hiemstra

Keyword(s):

Innate Immunity ◽

Immune Responses ◽

Wound Repair ◽

First Line ◽

Gram Negative ◽

Enveloped Viruses ◽

Effector Molecules ◽

Gram Positive Bacteria ◽

Wide Range ◽

Micro Organisms

Innate immunity provides an effective first line of defence against infections. This is of particular importance in the lung, an organ that is exposed to a large number of pathogens that are inhaled. Antimicrobial peptides play an important role in the defence against these pathogens as effector molecules of innate immunity. These peptides are mainly produced by phagocytes and epithelial cells, and kill a wide range of micro-organisms: Gram-negative and Gram-positive bacteria, fungi and (enveloped) viruses. However, it is increasingly evident that these peptides not only act as endogenous antibiotics, but also display a range of other functions, including activities that are involved in regulating immune responses and inflammation, and wound repair. In this review, these activities are highlighted and their role in inflammatory lung disorders is discussed.

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Antibacterial Activity by Hemolymph Defensin from the Hard Tick Haemaphysalis longicornis

10.20944/preprints201801.0115.v1 ◽

2018 ◽

Author(s):

Yurika Yada ◽

Melbourne Rio Talactac ◽

Kodai Kusakisako ◽

Emmanuel Pacia Hernandez ◽

Remil Linggatong Galay ◽

...

Keyword(s):

Innate Immunity ◽

Antibacterial Activity ◽

Antimicrobial Peptides ◽

Micrococcus Luteus ◽

Fluorescent Antibody ◽

Cysteine Residues ◽

Hard Tick ◽

Haemaphysalis Longicornis ◽

Gram Positive ◽

Gram Positive Bacteria

Ticks are key vectors of some important diseases of humans and animals. Although they are carriers of disease agents, the viability and development of ticks are not harmed by the infectious agents due to their innate immunity. Antimicrobial peptides directly protect hosts against pathogenic agents such as viruses, bacteria, and parasites. Among the identified and characterized antimicrobial peptides, defensins have been considerably well studied. Defensins, which contain intramolecular disulfide bridges between cysteine residues, are commonly found among fungi, plants, invertebrates, and vertebrates. The sequence of the tick hemolymph defensin (HEdefensin) gene from the hard tick Haemaphysalis longicornis was analyzed after identification and cloning from a cDNA library. HEdefensin has a predicted molecular mass of 8.15 kDa and a theoretical isoelectric point of 9.48. Six cysteine residues were also identified in the amino acids. The synthetic HEdefensin peptide only showed antibacterial activity against Gram-positive bacteria such as Micrococcus luteus. A fluorescence propidium iodide exclusion assay also showed that HEdefensin increased the membrane permeability of M. luteus. Additionally, an indirect fluorescent antibody test showed that HEdefensin binds to M. luteus. These results suggested that HEdefensin strongly affects the innate immunity of ticks against Gram-positive bacteria.

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Influence of Cell Wall Composition on the Fossilisation of Bacteria and the Implications for the Search for Early Life Forms

International Astronomical Union Colloquium ◽

10.1017/s0252921100015025 ◽

1997 ◽

Vol 161 ◽

pp. 491-504 ◽

Cited By ~ 3

Author(s):

Frances Westall

Keyword(s):

Cell Wall ◽

Life Forms ◽

Cation Binding ◽

Positive Bacterium ◽

Gram Positive ◽

Gram Positive Bacteria ◽

Transmission Electron ◽

Hydrothermal Sediments ◽

Identification Of Bacteria ◽

The Difference

AbstractThe oldest cell-like structures on Earth are preserved in silicified lagoonal, shallow sea or hydrothermal sediments, such as some Archean formations in Western Australia and South Africa. Previous studies concentrated on the search for organic fossils in Archean rocks. Observations of silicified bacteria (as silica minerals) are scarce for both the Precambrian and the Phanerozoic, but reports of mineral bacteria finds, in general, are increasing. The problems associated with the identification of authentic fossil bacteria and, if possible, closer identification of bacteria type can, in part, be overcome by experimental fossilisation studies. These have shown that not all bacteria fossilise in the same way and, indeed, some seem to be very resistent to fossilisation. This paper deals with a transmission electron microscope investigation of the silicification of four species of bacteria commonly found in the environment. The Gram positiveBacillus laterosporusand its spore produced a robust, durable crust upon silicification, whereas the Gram negativePseudomonas fluorescens, Ps. vesicularis, andPs. acidovoranspresented delicately preserved walls. The greater amount of peptidoglycan, containing abundant metal cation binding sites, in the cell wall of the Gram positive bacterium, probably accounts for the difference in the mode of fossilisation. The Gram positive bacteria are, therefore, probably most likely to be preserved in the terrestrial and extraterrestrial rock record.

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Antimicrobial Peptides - Small but Mighty Weapons for Plants to Fight Phytopathogens

Protein and Peptide Letters ◽

10.2174/0929866526666190619112438 ◽

2019 ◽

Vol 26 (10) ◽

pp. 720-742 ◽

Cited By ~ 8

Author(s):

Kaushik Das ◽

Karabi Datta ◽

Subhasis Karmakar ◽

Swapan K. Datta

Keyword(s):

Antimicrobial Peptides ◽

Durable Resistance ◽

Defense Responses ◽

Defense System ◽

Biotechnological Potential ◽

Functional Aspects ◽

Low Concentrations ◽

Wide Range ◽

Vital Component ◽

Pathogen Entry

Antimicrobial Peptides (AMPs) have diverse structures, varied modes of actions, and can inhibit the growth of a wide range of pathogens at low concentrations. Plants are constantly under attack by a wide range of phytopathogens causing massive yield losses worldwide. To combat these pathogens, nature has armed plants with a battery of defense responses including Antimicrobial Peptides (AMPs). These peptides form a vital component of the two-tier plant defense system. They are constitutively expressed as part of the pre-existing first line of defense against pathogen entry. When a pathogen overcomes this barrier, it faces the inducible defense system, which responds to specific molecular or effector patterns by launching an arsenal of defense responses including the production of AMPs. This review emphasizes the structural and functional aspects of different plant-derived AMPs, their homology with AMPs from other organisms, and how their biotechnological potential could generate durable resistance in a wide range of crops against different classes of phytopathogens in an environmentally friendly way without phenotypic cost.

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Enzymes as a Reservoir of Host Defence Peptides

Current Topics in Medicinal Chemistry ◽

10.2174/1568026620666200327173815 ◽

2020 ◽

Vol 20 (14) ◽

pp. 1310-1323

Author(s):

Andrea Bosso ◽

Antimo Di Maro ◽

Valeria Cafaro ◽

Alberto Di Donato ◽

Eugenio Notomista ◽

...

Keyword(s):

Innate Immunity ◽

Biological Activity ◽

Internal Structure ◽

Catalytic Properties ◽

Cellular Responses ◽

Host Defence ◽

Present Review ◽

Active Peptides ◽

Wide Range

Host defence peptides (HDPs) are powerful modulators of cellular responses to various types of insults caused by pathogen agents. To date, a wide range of HDPs, from species of different kingdoms including bacteria, plant and animal with extreme diversity in structure and biological activity, have been described. Apart from a limited number of peptides ribosomally synthesized, a large number of promising and multifunctional HDPs have been identified within protein precursors, with properties not necessarily related to innate immunity, consolidating the fascinating hypothesis that proteins have a second or even multiple biological mission in the form of one or more bio-active peptides. Among these precursors, enzymes constitute certainly an interesting group, because most of them are mainly globular and characterized by a fine specific internal structure closely related to their catalytic properties and also because they are yet little considered as potential HDP releasing proteins. In this regard, the main aim of the present review is to describe a panel of HDPs, identified in all canonical classes of enzymes, and to provide a detailed description on hydrolases and their corresponding HDPs, as there seems to exist a striking link between these structurally sophisticated catalysts and their high content in cationic and amphipathic cryptic peptides.

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Plant antimicrobial peptides: structures, functions, and applications

Botanical Studies ◽

10.1186/s40529-021-00312-x ◽

2021 ◽

Vol 62 (1) ◽

Author(s):

Junpeng Li ◽

Shuping Hu ◽

Wei Jian ◽

Chengjian Xie ◽

Xingyong Yang

Keyword(s):

Antimicrobial Activity ◽

Antimicrobial Peptides ◽

Agricultural Production ◽

Food Additives ◽

Antimicrobial Activities ◽

Gram Positive Bacteria ◽

Potential Applications ◽

Potential Applicability ◽

Bacteria And Fungi ◽

Positively Charged

AbstractAntimicrobial peptides (AMPs) are a class of short, usually positively charged polypeptides that exist in humans, animals, and plants. Considering the increasing number of drug-resistant pathogens, the antimicrobial activity of AMPs has attracted much attention. AMPs with broad-spectrum antimicrobial activity against many gram-positive bacteria, gram-negative bacteria, and fungi are an important defensive barrier against pathogens for many organisms. With continuing research, many other physiological functions of plant AMPs have been found in addition to their antimicrobial roles, such as regulating plant growth and development and treating many diseases with high efficacy. The potential applicability of plant AMPs in agricultural production, as food additives and disease treatments, has garnered much interest. This review focuses on the types of plant AMPs, their mechanisms of action, the parameters affecting the antimicrobial activities of AMPs, and their potential applications in agricultural production, the food industry, breeding industry, and medical field.

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Antimicrobial Nodule-Specific Cysteine-Rich Peptides Induce Membrane Depolarization-Associated Changes in the Transcriptome of Sinorhizobium meliloti

Applied and Environmental Microbiology ◽

10.1128/aem.01791-13 ◽

2013 ◽

Vol 79 (21) ◽

pp. 6737-6746 ◽

Cited By ~ 64

Author(s):

Hilda Tiricz ◽

Attila Szűcs ◽

Attila Farkas ◽

Bernadett Pap ◽

Rui M. Lima ◽

...

Keyword(s):

Stress Responses ◽

Sinorhizobium Meliloti ◽

Antimicrobial Agents ◽

Cellular Functions ◽

Gram Positive ◽

Content Type ◽

Gram Positive Bacteria ◽

Peptide Family ◽

Wide Range ◽

Natural Target

ABSTRACTLeguminous plants establish symbiosis with nitrogen-fixing alpha- and betaproteobacteria, collectively called rhizobia, which provide combined nitrogen to support plant growth. Members of the inverted repeat-lacking clade of legumes impose terminal differentiation on their endosymbiotic bacterium partners with the help of the nodule-specific cysteine-rich (NCR) peptide family composed of close to 600 members. Among the few tested NCR peptides, cationic ones had antirhizobial activity measured by reduction or elimination of the CFU and uptake of the membrane-impermeable dye propidium iodide. Here, the antimicrobial spectrum of two of these peptides, NCR247 and NCR335, was investigated, and their effect on the transcriptome of the natural targetSinorhizobium melilotiwas characterized. Both peptides were able to kill quickly a wide range of Gram-negative and Gram-positive bacteria; however, their spectra were only partially overlapping, and differences were found also in their efficacy on given strains, indicating that the actions of NCR247 and NCR335 might be similar though not identical. Treatment ofS. meliloticultures with either peptide resulted in a quick downregulation of genes involved in basic cellular functions, such as transcription-translation and energy production, as well as upregulation of genes involved in stress and oxidative stress responses and membrane transport. Similar changes provoked mainly in Gram-positive bacteria by antimicrobial agents were coupled with the destruction of membrane potential, indicating that it might also be a common step in the bactericidal actions of NCR247 and NCR335.

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