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Botanicals and the Gut Microbiome
Published in Namrita Lall, Medicinal Plants for Cosmetics, Health and Diseases, 2022
An individual’s immune system development is influenced by their intestinal microbiota and the metabolites they produce. The intestinal epithelial cells have the ability to signal an innate immune response to prevent any threats from pathogens (Vyas and Ranganathan, 2012). The most significant protection provided by the intestinal microbiota is known as the barrier or competitive-exclusion effect. This effect is the ability of the intestinal bacteria to produce antimicrobial compounds such as bacteriocins to compete for nutrients and a site of attachment in the gut lining. In this way, the intestinal bacteria prevent the colonization of pathogenic bacteria in the gut (Guarner et al., 2003). The intestinal bacteria are known for their production of bacteriocins and this is a property distributed throughout most of the gastrointestinal bacteria (Guarner et al., 2003).
Anti-Cancer Agents from Natural Sources
Published in Rohit Dutt, Anil K. Sharma, Raj K. Keservani, Vandana Garg, Promising Drug Molecules of Natural Origin, 2020
Debasish Bandyopadhyay, Felipe Gonzalez
Bacteriocins are antimicrobial peptides, produced by various bacteria (Cotter et al., 2013), first discovered by Andre Gratia in 1925. Around this time, antibiotics related to bacteriocins were also discovered (Gartia et al., 2000). Overall, their discovery revolutionized the way we see nature and opened a new chapter in drug discovery research. Classification of bacteriocins vary widely, usually depended on which bacteria they were derived from, either gram-negative or gram-positive. Gram-negative bacteria-derived bacteriocins are classified through their molecular weights: high or low (Djamel et al., 2011). Gram-positive bacteria-originated bacteriocins are classified into three classes: I, II, and III, based on molecular weights (Cotter et al., 2006). Class I bacteriocins are small lantibiotics (<5 kDA) that contain polycyclic thioether amino acids, specifically lanthionine (Hyungjae et al., 2010). Class II bacteriocins are small (<10 kDA) peptides that cannot be modified. Class III bacteriocins are large (>30 kDA) proteins. Although most classifications are through size and class type, some bacteriocins are classified through their mechanism of action, which varies widely but usually targets cell membrane (Cotter et al., 2013). Because of their wide range and action potential, many bacteriocins are being studied to evaluate their effects on cancers cells.
Prospective Therapeutic Applications of Bacteriocins as Anticancer Agents
Published in Ananda M. Chakrabarty, Arsénio M. Fialho, Microbial Infections and Cancer Therapy, 2019
Lígia F. Coelho, Nuno Bernardes, Arsénio M. Fialho
Microorganisms have been among the most important sources of bioactive compounds, from antibiotics to chemotherapeutic drugs. Bacteriocins are small proteins or ribosomally synthesized peptides with significant relevance in human health, contributing as probiotics, antimicrobials, and anticancer agents, which are produced by both gram-positive and gram-negative bacteria and by Archaea [1, 2]. They are usually classified into peptides that endure significant post-translational modifications (class I) and unmodified peptides (class II), although other classifications have been proposed [3]. These molecules represent a subgroup of the anticancer peptides (ACPs) identified to date. ACPs have been proved to be a resourceful strategy for the molecularly targeted cancer drug discovery and development process. Peptide-based therapy has numerous advantages over small molecules, including high specificity, low production cost, high tumor penetration, and ease of synthesis and modification [4]. ACPs are reported to have efficient tissue penetration and uptake by heterogeneous cancer cells, endowed with intrinsic activity or synergized with existing therapeutics, which is of major relevance for the battle against chemotherapeutic drug resistance.
Effect of a bacteriocin-producing Streptococcus salivarius on the pathogen Fusobacterium nucleatum in a model of the human distal colon
Published in Gut Microbes, 2022
Garreth W. Lawrence, Niamh McCarthy, Calum J. Walsh, Tais M. Kunyoshi, Elaine M. Lawton, Paula M. O’Connor, Máire Begley, Paul D. Cotter, Caitriona M. Guinane
The gastrointestinal tract (GI) harbors trillions of diverse microbes, including candidate biotherapeutic bacteria such as probiotics. Probiotic bacteria are defined as “live microorganisms that, when administered in adequate amounts, confer a health benefit on the host”.1 Probiotic bacteria can exert health benefits on its host through several mechanisms, including targeting pathogenic microbes via antimicrobial production.2 Therefore, the GI tract has been regarded as a reservoir for novel antimicrobials, and extensive research has been focused on screening bacterial gut isolates for antimicrobial compounds such as bacteriocins.3,4 Bacteriocins are antimicrobial peptides produced by specific bacteria, which exhibit potent activity against other bacteria.5 It should be noted that the in vitro inhibitory activity of bacteriocins against a particular target does not necessarily translate to the gut environment. Ex vivo models provide a convenient means of bridging the gap between in vitro and in vivo investigations to assess the impact of different modulators on the gut microbiota.6,7 Indeed, ex vivo models of the colon have been used on a number of occasions to evaluate the impact of antibiotics8 and bacteriocins9,10 on intestinal microbial communities.
Enterotoxigenic Escherichia coli: intestinal pathogenesis mechanisms and colonization resistance by gut microbiota
Published in Gut Microbes, 2022
Yucheng Zhang, Peng Tan, Ying Zhao, Xi Ma
Bacteriocins are bacterially produced peptides that are active against other bacteria and against which the producer has a specific immunity mechanism.142,143 Probiotics could produce bacteriocins to facilitate its probiotic function in a number of ways.142 For example, bacteriocins may function as antimicrobial peptides, directly eradicating pathogens;144 they may act as colonizing peptides, helping the colonization of a probiotic in the intestine trat;145 or they may serve as signaling peptides, signaling other bacteria or the immune system of the host.146 Mircocins produced by Gram-negative bacteria belong to the large class of bacteriocins.147 Probiotic Escherichia coli Nissle 1917 could utilize microcins to limit the expansion and colonization of pathogenic E. coli in infected mice.148
Synergistic antibacterial and anti-biofilm activity of nisin like bacteriocin with curcumin and cinnamaldehyde against ESBL and MBL producing clinical strains
Published in Biofouling, 2020
Garima Sharma, Shweta Dang, Aruna K, Manjula Kalia, Reema Gabrani
Bacteriocins can be used as alternative therapeutic agents. They are small peptides synthesized by ribosomes and secreted by bacteria. Bacteriocins have been shown to be effective against multidrug-resistant bacteria (Rodrigues et al. 2019). Bacteriocins have been mainly used as food preservatives, but now their biomedical applications have also come to the forefront. Lactic acid bacteria (LAB) have gained interest as being sources of bacteriocin because of their “Generally Recognised as Safe (GRAS)” status by the US FDA. Several LAB have been reported to be a potential source of bacteriocin, but only half of the total 230 bacteriocins from LAB have been well characterized to date (Alvarez-Sieiro et al. 2016). The known bacteriocins, namely nisin, lacticin 3147, and mutacin B-Ny266, isolated and purified from LAB, have antimicrobial activity against Streptococcus pneumoniae, vancomycin-resistant enterococci, Clostridium difficile and many more bacterial species (Goldstein et al. 1998; Cotter et al. 2013).