Prokaryotic Antimicrobial Peptides (original) (raw)

Update of peptides with antibacterial activity

For many years a battle has been going on between bacteria and humans, with bacteria trying to survive against the antibiotics used by humans. Bacteria are found to be dominant in this battle since they can develop resistance. In fact, in the last decade multi-, extended-and pan-drug resistant bacteria have been isolated. On the other hand, the number of new antibiotics approved by the FDA has dramatically decreased during the last 20 years. Therefore, there is a desperate need for developing new types of antibacterial agents, where antimicrobial peptides may play an important role. This review provides an update of the recently identified antimicrobial peptides. Three valid approaches for developing a future antibacterial agent, as are the mechanisms of action as well as the in vitro and in vivo assays have been described in depth. In comparison to the antibacterial agents available at present, the targets for most of the antimicrobial peptides are not well known. However several proposals having been introduced for many antimicrobial peptides of different mechanisms of action, there still lies some uncertainty about their utility. Hundreds of antimicrobial peptides have been tested in vitro against all types of bacteria, but in this review we will highlight only those which have been tested against the most important Grampositive and Gram-negative bacteria. The last step to get a potential antibiotic includes studies with an in vivo model. Therefore only antimicrobial peptides with good activity are tested that have been described in this review.

Peptides and proteins with antimicrobial activity

Indian Journal of Pharmacology, 2008

The increase of microbial resistance to antibiotics has led to a continuing search for newer and more effective drugs. Antimicrobial peptides are generally found in animals, plants, and microorganisms and are of great interest to medicine, pharmacology, and the food industry. These peptides are capable of inhibiting pathogenic microorganisms. They can attack parasites, while causing little or no harm to the host cells. The defensins are peptides found in granules in the polymorphonuclear neutrophils (PMNs) and are responsible for the defense of the organism. Several animal defensins, like dermaseptin, antileukoprotease, protegrin, and others, have had their activities and efficacy tested and been shown to be effective against bacteria, fungi, and protists; there are also specific defensins from invertebrates, e.g., drosomycin and heliomicin; from plants, e.g., the types A and B; and the bacteriocins, e.g., acrocin, marcescin, etc. The aim of the present work was to compile a comprehensive bibliographic review of the diverse potentially antimicrobial peptides in an effort to systematize the current knowledge on these substances as a contribution for further researches. The currently available bibliography does not give a holistic approach on this subject. The present work intends to show that the mechanism of defense represented by defensins is promising from the perspective of its application in the treatment of infectious diseases in human, animals and plants.

Antimicrobial Peptides from Bacterial Sources-A Review

2020

Antimicrobial peptides are host defense peptides composed of long chain of amino acids with a lot many properties. The antimicrobial peptides produced by bacteria are collectively called as bacteriocins. Bacteriocins are produced by both Gram positive and Gram negative bacteria and are positively charged or amphiphilic molecules. Even though both Gram negative and Gram positive bacteria produce bacteriocins, those produced by Gram positive Lactic Acid Bacteria are most studied and diverse in nature. They are classified into lantibiotics and Cl;ass II peptides. These peptides are having antibacterial, immunomodulatory activities and even antibacterial resistance. They act by forming pores in the cell membrane and thus causing the cell death. Bacteria secrete these peptides as a defense strategy to defend their environment and also able to kill other bacteria. Even though having many beneficial properties and uses, there many challenges in clinical use of these peptides.

Antimicrobial Peptides Published

Milk proteins constitute a natural reservoir of bioactive peptides with physiological and ⁄ or antimicrobial properties, the release of which requires hydrolysis of the precursor molecules by digestive proteases or by fermentation with proteolytic micro-organisms. Depending on the digestive or microbial proteases used, an array of bioactive peptides would be released either from caseins or whey proteins, but only a small part of these peptides has so far been identified and characterised with respect to their antimicrobial activity. The antimicrobial peptides known thus far have proven to be potent inhibitors to the growth of a wide range of undesirable micro-organisms of health or spoilage significance. Nevertheless, previous research work has largely been oriented towards their possible application in medicine, which has hindered their high potential as food-grade biopreservatives and ⁄ or as supplements in functional foods. This review attempts to study the literature pertaining to antimicrobial peptides derived from major milk proteins (caseins, a-lactalbumin and b-lactoglobulin) upon hydrolysis either by digestive proteases or by fermentation with proteolytic lactic acid bacteria. Their possible application in the food industry and their mechanism of action will also be discussed. Reference antimicrobial peptides produced by living micro-organisms as innate immune defence components against microbial infections will occasionally be invoked for comparison purposes.

Antimicrobial Peptides Classification, action and therapeutic potential.pdf

Microbial resistance to conventional antibiotics is one of the most outstanding medical and scientific challenges. Antimicrobial resistance is an alarming threat to public health at the global level. This is due to acquired resistance to antimicrobial agents by microorganisms associated directly to the indiscriminate use of antibiotics. To combat the ill effects of antibiotic resistance several substances known as antimicrobial peptides have been used. Antimicrobial peptides (AMPs) are an essential part of innate immunity that evolved in most living organisms over 2.6 billion years to combat microbial challenge. The naturally occurring peptides are seen as a promising alternative to regular antibiotics, because they are still effective defence mechanism against bacteria despite exposure throughout the centuries. These AMPs use different mechanisms to kill the microbial pathogens. Different classes of the AMPs have been discovered that have proved to be of immense advantage in combating different pathogens. This review shall give a brief discussion regarding the classification, mode of action and therapeutic potential of AMPs.

Activities of synthetic peptides against human pathogenic bacteria

Polish journal of microbiology / Polskie Towarzystwo Mikrobiologów = The Polish Society of Microbiologists

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