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Cell-Cell Communication in Lactic Acid Bacteria
Published in Marcela Albuquerque Cavalcanti de Albuquerque, Alejandra de Moreno de LeBlanc, Jean Guy LeBlanc, Raquel Bedani, Lactic Acid Bacteria, 2020
Emília Maria França Lima, Beatriz Ximena Valencia Quecán, Luciana Rodrigues da Cunha, Bernadette Dora Gombossy de Melo Franco, Uelinton Manoel Pinto
Bacteriocins produced by LAB comprise a diverse group of antimicrobial peptides; however, two main categories have been established based on their structural modifications, their size, their thermostability, and mechanisms of action. The first category refers to Class I (lantibiotics) which are small cationic membrane-active peptides from 19 to 38 amino acid residues that contain lanthionine or ß-methyl lanthionine, which undergo post-translational modifications and exert their effect at the level of the membrane and the cell wall. In this group, nisin is the most representative bacteriocin (Cotter et al. 2005, López et al. 2008, Rea et al. 2011, Silva et al. 2018). On the other hand, class II (non-lantibiotics) is defined as heat-stable bacteriocins, constituted by 30 to 70 amino acid residues that do not contain lanthionine. They induce pore formation in the membrane of the target cells. These bacteriocins are divided into subclasses: subclass IIa anti-listeria, pediocin-like bacteriocins is the largest of all, and its members have the amino terminal motif containing one or two disulfide bridges (Nes et al. 2013); subclass IIb is formed by bacteriocins that require the combined action of two peptides to have activity because they cannot act individually (López et al. 2008, Rea et al. 2011); subclass IIc the cyclic bacteriocins due to the covalent attachment of the carboxy and amino terminal ends and; subclass IId which is formed by a variable group of linear non pediocin-like peptides (Sánchez et al. 2003, López et al. 2008, Nes et al. 2013).
Bacteriocins as Anticancer Peptides: A Biophysical Approach
Published in Ananda M. Chakrabarty, Arsénio M. Fialho, Microbial Infections and Cancer Therapy, 2019
Filipa D. Oliveira, Miguel A.R.B. Castanho, Diana Gaspar
Class I bacteriocins, known as lantibiotics or lanthionine-containing antibiotics, are small and low-weighted peptides, usually less than 5 kDa, and have 19 to 38 amino acid residues [22, 56]. These peptides are heat stable and exhibit post-translation modifications, such as the substitution of d-alanine for l-serine amino acid residues [22, 56]. They also contain polycyclic thioether amino acids, such as lanthionine and β-methyllanthionine, which promote the formation of disulfide bonds between amino acid residues, resulting in internal “rings” that confer lantibiotics their unique structure with specific features [22, 56]. Lantibiotics also contain unsaturated amino acids, namely dehydroalanine and 2-aminoisobutyric acid [22, 56]. This complex structure limits a subdivision of the class of lantibiotics, and there are several different proposed subclassifications [56, 60, 61]. A subclassification is based on peptide charge, structure, and target. Type A lantibiotics, such as nisin and lacticin 3147, are screw shaped, elongated, and flexible and exhibit a positive net charge [22, 56]. Such lantibiotics act on the cell membrane, inducing pore formation and leading to the depolarization of the cytoplasmic membrane [22]. Type B lantibiotics exhibit either a neutral or a negative net charge and a globular shape. These lantibiotics’ action consists in disturbing enzymatic reactions occurring within the target cell, interfering with cell wall synthesis, for example [22]. Mersacidin is representative of type B lantibiotics [61].
Role of Bacteria in Dermatological Infections
Published in K. Balamurugan, U. Prithika, Pocket Guide to Bacterial Infections, 2019
Thirukannamangai Krishnan Swetha, Shunmugiah Karutha Pandian
S. epidermidis is a ubiquitous gram-positive skin and mucosal membrane colonizer, which exerts a mutualistic relationship with host. It forms the major part of microbial barrier that precludes the colonization of other pathogens. In a competitive environment, it secretes lantibiotics (i.e., lanthionine-containing antibacterial peptides) often referred as bacteriocins, which prevent the colonization of S. aureus and GAS (Sahl, 1994; Cogen et al., 2007). Also, accessory gene regulator (agr) locus found in commensal S. epidermidis produces peptide pheromones that activate the agr QS system of competing bacteria, which in turn, reduces colonization and down-regulates the expression of virulence factors by increasing the production of pheromones such as phenol soluble modulin (Otto, 2001). In addition, S. epidermidis boosts the host immune defense by eliciting the signaling of toll like receptor (TLR). The pattern recognition receptors TLRs, in turn, specifically recognize different pathogen-associated molecular patterns and activate the host immune system accordingly.
Modulation of pathogenic oral biofilms towards health with nisin probiotic
Published in Journal of Oral Microbiology, 2020
Allan Radaic, Changchang Ye, Brett Parks, Li Gao, Ryutaro Kuraji, Erin Malone, Pachiyappan Kamarajan, Ling Zhan, Yvonne L. Kapila
Recently, the potential for using a nisin bacteriocin and nisin probiotic in biomedical applications has been highlighted [8–11]. Nisin is a class I Lantibiotic bacteriocin produced by the Gram-positive bacterium Lactococcus lactis and it contains 34 amino acids in a penta-cyclic structure [12,13]. Nisin is active against both Gram-positive and Gram-negative bacteria, including Streptococcus aureus, Listeria monocytogenes, Fusobacterium nucleatum, Porphyromonas gingivalis and Treponema denticola [8,12]. Nisin itself and nisin-expressing L. lactis spp. have been used successfully to abrogate infections associated with drug-resistant pathogens, gastrointestinal infections, respiratory tract infections, skin and soft tissue infections, mastitis, HNC, and other oral diseases using in vitro and in vivo models [9]. In addition, studies led by our group support its use as an antitumor agent for HNC, and in combating biofilms that contain disease-associated bacteria [7,8,14]. Specifically, we have shown nisin’s dose-dependent efficacy in abrogating the growth of pathogenic planktonic bacteria and bacteria present in oral biofilms associated with caries, periodontal disease, and persistent endodontic infections without inducing cytotoxicity to human oral cells [8]. Furthermore, we have shown nisin’s efficacy in abrogating HNC carcinogenesis and in extending survival in HNC mouse models [14]. However, a nisin-producing probiotic has not been tested for its effects on oral biofilms, especially those relevant to oral diseases.
Improving the attrition rate of Lanthipeptide discovery for commercial applications
Published in Expert Opinion on Drug Discovery, 2018
The emergence of multidrug-resistant bacteria has become a severe problem in clinic, including vancomycin-resistant Enterococcus (VRE), methicillin-resistant Staphylococcus aureus (MRSA), and drug-resistant Streptococcus pneumoniae [1]. Vancomycin and daptomycin are often referred to as ‘antibiotics of last sort,’ while increasingly daptomycin nonsusceptible VRE is being reported [2]. Novel antibiotics with potent activity are needed to overcome drug-resistant infections. Lanthipeptides are a class of lanthionine (Lan)-containing, ribosomally synthesized and posttranslationally modified peptides (RiPPs). Within this class of molecules, peptides with antimicrobial activity are termed as lantibiotics [3]. They have distinct mode of action than the traditionally used antibiotics and are gaining more and more attention.
An overview of lantibiotic biosynthetic machinery promiscuity and its impact on antimicrobial discovery
Published in Expert Opinion on Drug Discovery, 2020
Lantibiotics represent a group of antimicrobial peptides that possess the necessary attributes for the treatment of multidrug resistant infections. The expansion of whole genome sequencing has resulted in the discovery of numerous novel lantibiotic clusters, each of which represent potentially novel antimicrobial agents. These can be further engineered by utilizing the promiscuous nature of the biosynthetic genes and the modular nature of lantibiotic ring formation to improve the pharmacological properties of these versatile agents. The continued discovery of novel lantibiotics and development of engineering strategies to improve them will undoubtedly lead to an increase in lantibiotics in pre-clinical and clinical trials for the treatment of pathogenic bacteria.