Bacteria peptide antibiotics produced

Enramycin is also a linear-ring peptide antibiotic produced by Streptomyces fungicidicus. Enramycin consists of two main components called enramycin A and enramycin B. It is active against gram-positive and acid-fast bacteria and is an approved growth promoter for poultry and swine. Enramycin is usually incorporated in feeds in the form of its monohydrochloride form. 

Finally, bacitracins are peptide antibiotics produced by Bacillus subtilis and B. licheniformis. Over 20 components are contained in the bacitracin complex medium, among which the major active components are bacitracin A and F (Fig. 3). They exhibit an inhibitory activity against Gram-positive bacteria and are among the most commonly used antibiotics as animal feed additives. 

Cyclic peptide antibiotics produced by bacteria of Bacillus genus 01KPS103. 

Thiopeptin is a sulfur-containing peptide antibiotic complex produced by Streptomyces tateyamensis. It is composed of five closely related components, the thiopeptins Ai, A2, A3, A4, and B (8). Commercially available thiopeptin is primarily composed of thiopeptins B. This antibiotic is active against gram-positive bacteria and is used exclusively as a feed additive for pigs. 

There are many examples of peptides that cannot form transmembrane channels on their own but can do so through aggregation. The gramicidin antibiotics, produced by bacteria as part of their chemical defence system, are only 1.6 nm or so in length [11], Specific placement of side chains, such as four tryptophan residues towards the C-terminus, ensures that the helix penetrates cell membranes to a particular depth but does not pass through the membrane. 

The D-enantiomeric amino acids form by nonprotein synthesis inside bacteria in the form of peptide antibiotics. Although proteins predominate in today s DNA world, one assumes that proteins were in a minority at the beginning of the RNA world. It is likely that several pathways independently produced the first smaller peptides early on. Many essential coenzymes consist not only of nucleotide derivatives but also amino acids Coenzyme A, NADH+, S-adenosyl-methionine, tetrahydrofolate, and many more, see below. 

Peptide antibiotics are mainly produced by different strains of bacteria and fungi (Ref. 2, 21). They have frequently been reported to appear late in the growth phase (Ref. 21). During studies on tyrocidine biosynthesis in Baoiltus brevis, Lee and Lipmann (l8) found that tyrocidine synthetase was formed at stage 2. 

Tyrocidins homodetic, homomeiic, cyclic peptide antibiotics active against Gram-positive bacteria. Like the Gramicidins (see), X are produced by Bacillus brevis. Hie structure of tyrocidin A, confirmed by total synthesis, is cyclo-(-Val-Om-Leu-D-Phe-Pro-Phe-D-Phe-Asn-Gln-IJr-). In tyrocidin B, Phe is replaced by Trp. In tyrocidin C, Phe is replaced by Tip, D-Phc7 by D-Hp, and Asng by Asp. Tyrocidin E differs from tyrocidin A by replacement of Asn by Asp, and Tyrio by Phe. 

Cationic peptides were traditionally isolated from natural sources or synthesized fay solid phase or solution phase chemistry. Moreover, they have recently been synthesized by recombinant DNA methods in bacteria (1). insect cells (2), and plants (3,4). The hta that cationic peptides are produced naturally by certain bacteria (e.g., see Qiapter 17), as well as the newly discovered ability to synthesize virtually any peptide by recombinant means in bacteria (1), clearly merits the use of the term "antibiotic for these compounds. Thus, cationic peptides represent not only the first new class of antibiotic in the past 30 yeais, but the world s first genetically engineeriitg antibacterials. 

Amides and esters are particularly important in biological systems. The phosphate and pyrophosphate derivatives found in DNA and RNA were illustrated in Section 20.12. The structure and chemistry of these compounds will be elaborated upon in Chapter 28. Peptides (discussed in Chapter 27, Section 27.4) are polymers composed of discrete amino acid units. They are joined together by so-called peptide bonds, which are actually amide bonds. Many natural peptides are produced by bacteria via nonribosomal peptide synthesis. Bacillus subtilis produces the heptapeptide surfactin (224), which has antibiotic and antifungal activity. ... 

Pore-Forming Toxins (Proteins and Peptides TC l.C.) represent a group of proteins that have considerably expanded over the last few years within the lactic acid bacteria group (Table 4.2). The production of bacteriocins is a very desirable trait with biotechnological applications. Bacteriocins are bacterially produced peptide antibiotics with the ability to kill a limited range of bacteria, usually but not always those that are closely related to the producer bacterium. 

Lastly, bacteriocins, a large set of ribosomal antibiotic peptides are produced by numerous strains of bacteria associated with marine invertebrates and vertebrates. Bacteriocin-producing bacteria mainly belong to the genera Aeromonas, Alteromonas, Cytophaga-Flavohacterium-Bacteroides group, Pseudoalteromonas and Vibrio. Bacteriocins and bacteriocin-like inhibitory substances (BUS) could be used as probiotics in the aquaculture industry (Desriac et al, 2010). 

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