101
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Sherwood EJ, Hesketh AR, Bibb MJ. Cloning and analysis of the planosporicin lantibiotic biosynthetic gene cluster of Planomonospora alba. J Bacteriol 2013; 195:2309-21. [PMID: 23475977 PMCID: PMC3650528 DOI: 10.1128/jb.02291-12] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2012] [Accepted: 03/04/2013] [Indexed: 01/08/2023] Open
Abstract
The increasing prevalence of antibiotic resistance in bacterial pathogens has renewed focus on natural products with antimicrobial properties. Lantibiotics are ribosomally synthesized peptide antibiotics that are posttranslationally modified to introduce (methyl)lanthionine bridges. Actinomycetes are renowned for their ability to produce a large variety of antibiotics, many with clinical applications, but are known to make only a few lantibiotics. One such compound is planosporicin produced by Planomonospora alba, which inhibits cell wall biosynthesis in Gram-positive pathogens. Planosporicin is a type AI lantibiotic structurally similar to those which bind lipid II, the immediate precursor for cell wall biosynthesis. The gene cluster responsible for planosporicin biosynthesis was identified by genome mining and subsequently isolated from a P. alba cosmid library. A minimal cluster of 15 genes sufficient for planosporicin production was defined by heterologous expression in Nonomuraea sp. strain ATCC 39727, while deletion of the gene encoding the precursor peptide from P. alba, which abolished planosporicin production, was also used to confirm the identity of the gene cluster. Deletion of genes encoding likely biosynthetic enzymes identified through bioinformatic analysis revealed that they, too, are essential for planosporicin production in the native host. Reverse transcription-PCR (RT-PCR) analysis indicated that the planosporicin gene cluster is transcribed in three operons. Expression of one of these, pspEF, which encodes an ABC transporter, in Streptomyces coelicolor A3(2) conferred some degree of planosporicin resistance on the heterologous host. The inability to delete these genes from P. alba suggests that they play an essential role in immunity in the natural producer.
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Affiliation(s)
- Emma J Sherwood
- Department of Molecular Microbiology, John Innes Centre, Norwich Research Park, Norwich, Norfolk, United Kingdom
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102
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Characterization of a regulatory network of peptide antibiotic detoxification modules in Lactobacillus casei BL23. Appl Environ Microbiol 2013; 79:3160-70. [PMID: 23455349 DOI: 10.1128/aem.00178-13] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Two-component systems (TCS) are major signal transduction pathways that allow bacteria to detect and respond to environmental and intracellular changes. A group of TCS has been shown to be involved in the response against antimicrobial peptides (AMPs). These TCS are characterized by the possession of intramembrane-sensing histidine kinases, and they are usually associated with ABC transporters of the peptide-7 exporter family (Pep7E). Lactobacillus casei BL23 encodes two TCS belonging to this group (TCS09 and TCS12) that are located next to two ABC transporters (ABC09 and ABC12), as well as a third Pep7E ABC transporter not genetically associated with any TCS (orphan ABC). This study addressed the involvement of modules TCS09/ABC09 and TCS12/ABC12 in AMP resistance. Results showed that both systems contribute to L. casei resistance to AMPs, and that each TCS constitutes a functional unit with its corresponding ABC transporter. Analysis of transcriptional levels showed that module 09 is required for the induction of ABC09 expression in response to nisin. In contrast, module 12 controls a wider regulon that encompasses the orphan ABC, the dlt operon (d-alanylation of teichoid acids), and the mprF gene (l-lysinylation of phospholipids), thereby controlling properties of the cell envelope. Furthermore, the characterization of a dltA mutant showed that Dlt plays a major role in AMP resistance in L. casei. This is the first report on the regulation of the response of L. casei to AMPs, giving insight into its ability to adapt to the challenging environments that it encounters as a probiotic microorganism.
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103
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Yount NY, Yeaman MR. Peptide antimicrobials: cell wall as a bacterial target. Ann N Y Acad Sci 2013; 1277:127-38. [PMID: 23302022 DOI: 10.1111/nyas.12005] [Citation(s) in RCA: 95] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Endogenous host defense peptides (HDPs) are among the most ancient immune mediators, constituting a first line of defense against invading pathogens across the evolutionary continuum. Generally, HDPs are small (<10 kDa), cationic, and amphipathic polypeptides, often broadly classified based on structure. In eukaryotes, major HDP classes include disulfide-stabilized (e.g., defensins), and α-helical or extended (e.g., cathelicidins) peptides. Prokaryote HDPs are generally referred to as bacteriocins, colicins, or lantibiotics, many of which undergo extensive posttranslational modifications. One target for prokaryotic and eukaryotic HDPs is the bacterial cell wall, an essential structural feature conserved among broad classes of bacteria. A primary building block of the cell wall is peptidoglycan, a macromolecular complex that arises through a series of reactions including membrane translocation, extracellular anchoring, and side chain cross-linking. Each of these steps represents a potential target for HDP inhibition, leading to bacteriostatic or bactericidal outcomes. Thus, understanding the relationships between HDPs and cell wall targets may shed light on new peptide antimicrobial agents and strategies to meet the daunting challenge of antibiotic resistance.
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Affiliation(s)
- Nannette Y Yount
- Division of Infectious Diseases, Los Angeles County, California, USA
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104
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Laukova A, Turek P. Application of nisin into slovak fermented salami Púchov. POTRAVINARSTVO 2012. [DOI: 10.5219/218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Púchov salami is favorite fermented salami among Slovak consumers. Nisin is the only bacteriocin accepted by European Commission for a commercial use as additive for food preservation (although not commonly used in meat products). Because of its possibility to prolonge shelf-life of the products and its antimicrobial activity, its effect in dry fermented Slovak salami Púchov experimentally inoculated with Listeria innocua Li1 strain was checked. The initial number of L. innocua Li1 in the inoculated salami mixtures was 104 CFU/g (log 10; 4.04 ± 0 07). After nisin addition, the count of Li1 strain in the meat samples (inoculated with Li1 and treated by nisin) was 1.36±0.07 CFU/g; difference 2.68 logarithmic cycle was noted between Li and Li/Ni samples. At day 2, the difference 3.23 log cycle was detected between Li1 and Li/Ni samples (Li:5.46±0.08, Li/Ni: 2.14±0.07 CFU/g); at weeks 3, 4, it was 1.69 and 1.80 log cycle. Activity of nisin itself was not recovered from the experimental salamis by the analytical method; however, its inhibitory effect was shown by Li1 count decrease. The pH in salamis during processing was almost at the same level (5.52, 5.53, 5.55). Water activity was not negatively influenced. Water content in Li/Ni salamis reached almost requested levels (maximum percentage of water requested is 34 %).
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105
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Aly S, Floury J, Piot M, Lortal S, Jeanson S. The efficacy of nisin can drastically vary when produced in situ in model cheeses. Food Microbiol 2012; 32:185-90. [DOI: 10.1016/j.fm.2012.06.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2011] [Revised: 06/05/2012] [Accepted: 06/05/2012] [Indexed: 11/29/2022]
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106
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Leisner JJ, Haaber J. Intraguild predation provides a selection mechanism for bacterial antagonistic compounds. Proc Biol Sci 2012; 279:4513-21. [PMID: 22951735 DOI: 10.1098/rspb.2012.1179] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Bacteriocins are bacterial proteinaceous toxins with bacteriostatic or bacteriocidal activity towards other bacteria. The current theory on their biological role concerns especially colicins, with underlying social interactions described as an example of spite. This leads to a rock-paper-scissors game between colicin producers and sensitive and resistant variants. The generality of this type of selection mechanism has previously been challenged with lactic acid bacterial (LAB) bacteriocins as an example. In the natural environment of LAB, batch cultures are the norm opposed to the natural habitats of Escherichia coli where continuous cultures are prevailing. This implies that fitness for LAB, to a large degree, is related to survival rates (bottleneck situations) rather than to growth rates. We suggest that the biological role of LAB bacteriocins is to enhance survival in the stationary growth phase by securing a supply of nutrients from lysed target cells. Thus, this social interaction is an example of selfishness rather than of spite. Specifically, it fits into an ecological model known as intraguild predation (IGP), which is a combination of competition and predation where the predator (LAB bacteriocin producer) and prey (bacteriocin susceptible bacteria) share similar and often limited resources. We hypothesize that IGP may be a common phenomenon promoting microbial production of antagonistic compounds.
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Affiliation(s)
- J J Leisner
- Faculty of Health and Medical Sciences, Department of Veterinary Disease Biology, University of Copenhagen, Grønnegårdsvej 15, 1870 Frederiksberg C., Denmark.
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107
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Jasir A, Kasprzykowski F, Kasprzykowska R, Lindström V, Schalén C, Grubb A. New antimicrobial cystatin C-based peptide active against gram-positive bacterial pathogens, including methicillin-resistant Staphylococcus aureus and multiresistant coagulase-negative staphylococci. APMIS 2012; 111:1004-10. [PMID: 14629266 DOI: 10.1111/j.1600-0463.2003.t01-1-apm1111110.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We describe the synthesis and antibacterial properties of a novel antimicrobial peptidyl derivative, (2S)-2-(Nalpha-benzyloxycarbonyl-arginyl-leucylamido-1-[(E)-cinnamoylamido]-3-methylbutane, structurally based upon the inhibitory centre of the human cysteine protease inhibitor, cystatin C. The derivative, here called Cystapep 1, displayed antibacterial activity against several clinically important gram-positive bacteria. It displayed minimal inhibitory and bactericidal concentrations of about 16 microg/ml for both Staphylococcus aureus and Streptococcus pyogenes. In radial agar diffusion assays, groups A, B, C and G streptococci as well as staphylococci were generally susceptible to the action of Cystapep 1, whereas pneumococci and enterococci were less susceptible. No activity against gram-negative bacteria was observed. Cystapep 1 also showed high activity against methicillin-resistant S. aureus (MRSA) and multiantibiotic-resistant coagulase-negative staphylococci (CNS), suggesting that its mechanism of action differs from those of most currently used antibiotics.
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Affiliation(s)
- Aftab Jasir
- Department of Clinical Chemistry, University Hospital, Lund, Sweden
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108
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Chen S, Fahmi NE, Nangreave RC, Mehellou Y, Hecht SM. Synthesis of pdCpAs and transfer RNAs activated with thiothreonine and derivatives. Bioorg Med Chem 2012; 20:2679-89. [PMID: 22405920 PMCID: PMC3575115 DOI: 10.1016/j.bmc.2012.02.024] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2011] [Revised: 02/05/2012] [Accepted: 02/08/2012] [Indexed: 11/29/2022]
Abstract
N,S-diprotected L-thiothreonine and L-allo-thiothreonine derivatives were synthesized using a novel chemical strategy, and used for esterification of the dinucleotide pdCpA. The aminoacylated dinucleotides were then employed for the preparation of activated suppressor tRNA(CUA) transcripts. Thiothreonine and allo-thiothreonine were incorporated into a predetermined position of a catalytically competent dihydrofolate reductase (DHFR) analogue lacking cysteine, and the elaborated proteins were derivatized site-specifically at the thiothreonine residue with a fluorophore.
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Affiliation(s)
- Shengxi Chen
- Center for BioEnergetics, Biodesign Institute, and Department of Chemistry and Biochemistry, Arizona State University, Tempe, AZ 85287, USA
| | - Nour Eddine Fahmi
- Center for BioEnergetics, Biodesign Institute, and Department of Chemistry and Biochemistry, Arizona State University, Tempe, AZ 85287, USA
| | - Ryan C. Nangreave
- Center for BioEnergetics, Biodesign Institute, and Department of Chemistry and Biochemistry, Arizona State University, Tempe, AZ 85287, USA
| | - Youcef Mehellou
- Center for BioEnergetics, Biodesign Institute, and Department of Chemistry and Biochemistry, Arizona State University, Tempe, AZ 85287, USA
| | - Sidney M. Hecht
- Center for BioEnergetics, Biodesign Institute, and Department of Chemistry and Biochemistry, Arizona State University, Tempe, AZ 85287, USA
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109
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Müller A, Ulm H, Reder-Christ K, Sahl HG, Schneider T. Interaction of type A lantibiotics with undecaprenol-bound cell envelope precursors. Microb Drug Resist 2012; 18:261-70. [PMID: 22432708 DOI: 10.1089/mdr.2011.0242] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Lantibiotics are a unique group within the antimicrobial peptides characterized by the presence of thioether amino acids (lanthionine and methyllanthionine). These peptides are produced by and primarily act on Gram-positive bacteria exerting multiple activities at the cytoplasmic membrane of susceptible strains. Previously, the cell wall precursor lipid II was identified as the molecular target for the prototype lantibiotic nisin. Binding and sequestration of lipid II blocks the incorporation of the central cell wall precursor into the growing peptidoglycan network, thereby inhibiting the formation of a functional cell wall. Additionally, nisin combines this activity with a unique target-mediated pore formation, using lipid II as a docking molecule. The interaction with the pyrophosphate moiety of lipid II is crucial for nisin binding. We show that, besides binding to lipid II, nisin interacts with the lipid intermediates lipid III (undecaprenol-pyrophosphate-N-acetyl-glucosamine) and lipid IV (undecaprenol-pyrophosphate-N-acetyl-glucosamine-N-acetyl-mannosamine) of the wall teichoic acid (WTA) biosynthesis pathway. Binding of nisin to the precursors was observed at a stoichiometry of 2:1. The specific interaction with WTA precursors further promoted target-mediated pore formation in artificial lipid bilayers. Specific interactions with lipid III and lipid IV could also be demonstrated for related type A lantibiotics, for example, gallidermin, containing the conserved lipid-II-binding motif.
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Affiliation(s)
- Anna Müller
- Pharmaceutical Microbiology Section, Institute of Medical Microbiology, Immunology and Parasitology, University of Bonn, Bonn, Germany
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110
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Abstract
It is a given that new antibiotics are needed to combat drug-resistant pathogens. However, this is only a part of the need-we actually never had antibiotics capable of eradicating an infection. All pathogens produce a small subpopulation of dormant persister cells that are highly tolerant to killing by antibiotics. Once an antibiotic concentration drops, surviving persisters re-establish the population, causing a relapsing chronic infection. Persisters are especially significant when the pathogen is shielded from the immune system by biofilms, or in sites where the immune components are limited-in the nervous system, the stomach, or inside macrophages.Antibiotic treatment during a prolonged chronic infection of P. aeruginosa in the lungs of patients with cystic fibrosis selects for high-persister (hip) mutants. Similarly, treatment of oral thrush infection selects for hip mutants of C. albicans. These observations suggest a direct causality between persisters and recalcitrance of the disease. It appears that tolerance of persisters plays a leading role in chronic infections, while resistance is the leading cause of recalcitrance to therapy in acute infections. Studies of persister formation in E. coli show that mechanisms of dormancy are highly redundant. Isolation of persisters produced a transcriptome which suggests a dormant phenotype characterized by downregulation of energy-producing and biosynthetic functions. Toxin-antitoxin modules represent a major mechanism of persister formation. The RelE toxin causes dormancy by cleaving mRNA; the HipA toxin inhibits translation by phosphorylating elongation factor Ef-Tu, and the TisB toxin forms a membrane pore, leading to a decrease in pmf and ATP.
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Affiliation(s)
- Kim Lewis
- Department of Biology, Northeastern University, Boston, MA 02115, USA.
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111
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Keren I, Mulcahy LR, Lewis K. Persister Eradication: Lessons from the World of Natural Products. Methods Enzymol 2012; 517:387-406. [DOI: 10.1016/b978-0-12-404634-4.00019-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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112
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Aydillo C, Avenoza A, Busto JH, Jiménez-Osés G, Peregrina JM, Zurbano MM. A Biomimetic Approach to Lanthionines. Org Lett 2011; 14:334-7. [DOI: 10.1021/ol203068s] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Carlos Aydillo
- Departamento de Química, Universidad de La Rioja, Centro de Investigación en Síntesis Química, U.A.-C.S.I.C., E-26006 Logroño, Spain
| | - Alberto Avenoza
- Departamento de Química, Universidad de La Rioja, Centro de Investigación en Síntesis Química, U.A.-C.S.I.C., E-26006 Logroño, Spain
| | - Jesús H. Busto
- Departamento de Química, Universidad de La Rioja, Centro de Investigación en Síntesis Química, U.A.-C.S.I.C., E-26006 Logroño, Spain
| | - Gonzalo Jiménez-Osés
- Departamento de Química, Universidad de La Rioja, Centro de Investigación en Síntesis Química, U.A.-C.S.I.C., E-26006 Logroño, Spain
| | - Jesús M. Peregrina
- Departamento de Química, Universidad de La Rioja, Centro de Investigación en Síntesis Química, U.A.-C.S.I.C., E-26006 Logroño, Spain
| | - María M. Zurbano
- Departamento de Química, Universidad de La Rioja, Centro de Investigación en Síntesis Química, U.A.-C.S.I.C., E-26006 Logroño, Spain
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113
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Oldach F, Al Toma R, Kuthning A, Caetano T, Mendo S, Budisa N, Süssmuth RD. Lantibiotika-Kongenere mit nicht-kanonischen Aminosäuren durch ribosomale In-vivo-Peptidsynthese. Angew Chem Int Ed Engl 2011. [DOI: 10.1002/ange.201106154] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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114
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Oldach F, Al Toma R, Kuthning A, Caetano T, Mendo S, Budisa N, Süssmuth RD. Congeneric lantibiotics from ribosomal in vivo peptide synthesis with noncanonical amino acids. Angew Chem Int Ed Engl 2011; 51:415-8. [PMID: 22128014 DOI: 10.1002/anie.201106154] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2011] [Revised: 10/20/2011] [Indexed: 11/10/2022]
Abstract
Expanded repetoire: Synthetic amino acids translated into propeptides dramatically increase the chemical diversity of the two-component lantibiotic lichenicidin. This opens new routes towards novel and unique peptide antibiotic sequences, which could display features important for medical applications.
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Affiliation(s)
- Florian Oldach
- Institut für Chemie, Technische Universität Berlin, 10623 Berlin, Germany
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115
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Abstract
Phosphatidylethanolamine (PE) is a major component in the mammalian plasma membrane. It is present mainly in the inner leaflet of the membrane bilayer in a viable, typical mammalian cell. However, accumulating evidence indicates that a number of biological events involve PE externalization. For instance, PE is concentrated at the surface of cleavage furrow between mitotic daughter cells and is correlated with the dynamics of contractile ring. In apoptotic cells, PE is exposed to the cell surface, thus providing a molecular marker for detection. In addition, PE is a cofactor in the anticoagulant mechanism, and a distinct distribution profile of PE has been documented at the blood-endothelium interface. These recent discoveries were made possible using PE-specific probes derived from duramycin and cinnamycin, which are members of type B lantibiotics. This review provides an account on the features of these PE-specific lantibiotics in the context of molecular probes for the characterization of PE on a cellular and tissue level. According to the existing data, PE is likely a versatile chemical species that plays a role in the regulation of defined biological and physiological activities. The utilities of lantibiotic-based molecular probes will help accelerate the characterization of PE as an abundant, yet elusive membrane component.
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Affiliation(s)
- Ming Zhao
- Department of Biophysics, Medical College of Wisconsin, Milwaukee, 53226, USA.
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116
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Abstract
The emergence of multi-drug-resistant bacteria such as methicillin-resistant strains of Staphylococcus aureus (MRSA), vancomycin-resistant enterococci, Pseudomonas aeruginosa, Acinetobacter baumannii and extended-spectrum β-lactamase (carbapenemase)-producing Enterobacteriaceae is becoming a serious threat. New-generation antimicrobial agents need to be developed. This includes the design of novel antimicrobial compounds and drug-delivery systems. This review provides an introduction into different classes of antimicrobial materials. The main focus is on strategies for the introduction of antimicrobial properties in polymer materials. These can be roughly divided into surface modification, inclusion of antimicrobial compounds that can leach from the polymer, and the introduction of polymer-bound moieties that provide the polymer with antimicrobial properties. One of the main challenges in the development of antimicrobial polymers for the use in contact with human tissue is the concomitant demand of non-cytotoxicity. Current research is strongly focused on the latter aspect.
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117
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Molloy EM, Cotter PD, Hill C, Mitchell DA, Ross RP. Streptolysin S-like virulence factors: the continuing sagA. Nat Rev Microbiol 2011; 9:670-81. [PMID: 21822292 DOI: 10.1038/nrmicro2624] [Citation(s) in RCA: 107] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Streptolysin S (SLS) is a potent cytolytic toxin and virulence factor that is produced by nearly all Streptococcus pyogenes strains. Despite a 100-year history of research on this toxin, it has only recently been established that SLS is just one of an extended family of post-translationally modified virulence factors (the SLS-like peptides) that are produced by some streptococci and other Gram-positive pathogens, such as Listeria monocytogenes and Clostridium botulinum. In this Review, we describe the identification, genetics, biochemistry and various functions of SLS. We also discuss the shared features of the virulence-associated SLS-like peptides, as well as their place within the rapidly expanding family of thiazole/oxazole-modified microcins (TOMMs).
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Affiliation(s)
- Evelyn M Molloy
- Department of Microbiology, University College Cork, Cork, Ireland
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118
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BRITO MARIAA, SOMKUTI GEORGEA, RENYE JR JOHNA. ISOLATION OF BACTERIOCIN-PRODUCING STAPHYLOCOCCI FROM BRAZILIAN CHEESE. J Food Saf 2011. [DOI: 10.1111/j.1745-4565.2011.00308.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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119
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Abstract
We report a bacterial system for the evolution of cyclic peptides that makes use of an expanded set of amino acid building blocks. Orthogonal aminoacyl-tRNA synthetase/tRNA(CUA) pairs, together with a split intein system were used to biosynthesize a library of ribosomal peptides containing amino acids with unique structures and reactivities. This peptide library was subsequently used to evolve an inhibitor of HIV protease using a selection based on cellular viability. Two of three cyclic peptides isolated after two rounds of selection contained the keto amino acid p-benzoylphenylalanine (pBzF). The most potent peptide (G12: GIXVSL; X=pBzF) inhibited HIV protease through the formation of a covalent Schiff base adduct of the pBzF residue with the ε-amino group of Lys 14 on the protease. This result suggests that an expanded genetic code can confer an evolutionary advantage in response to selective pressure. Moreover, the combination of natural evolutionary processes with chemically biased building blocks provides another strategy for the generation of biologically active peptides using microbial systems.
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120
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Crost EH, Ajandouz EH, Villard C, Geraert PA, Puigserver A, Fons M. Ruminococcin C, a new anti-Clostridium perfringens bacteriocin produced in the gut by the commensal bacterium Ruminococcus gnavus E1. Biochimie 2011; 93:1487-94. [PMID: 21586310 DOI: 10.1016/j.biochi.2011.05.001] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2011] [Accepted: 05/03/2011] [Indexed: 10/18/2022]
Abstract
When colonizing the digestive tract of mono-associated rats, Ruminococcus gnavus E1 - a bacterium isolated from human faeces - produced a trypsin-dependent anti-Clostridium perfringens substance collectively named Ruminococcin C (RumC). RumC was isolated from the caecal contents of E1-monocontaminated rats and found to consist of two antimicrobial fractions: a single peptide (RumCsp) of 4235 Da, and a mixture of two other peptides (RumCdp) with distinct molecular masses of 4324 Da and 4456 Da. Both RumCsp and RumCdp were as effective as metronidazole in combating C. perfringens and their activity spectra against different pathogens were established. Even if devoid of synergistic activity, the combination of RumCsp and RumCdp was observed to be much more resistant to acidic pH and high temperature than each fraction tested individually. N-terminal sequence analysis showed that the primary structures of these three peptides shared a high degree of homology, but were clearly distinct from previously reported amino acid sequences. Amino acid composition of the three RumC peptides did not highlight the presence of any Lanthionine residue. However, Edman degradation could not run beyond the 11th amino acid residue. Five genes encoding putative pre-RumC-like peptides were identified in the genome of strain E1, confirming that RumC was a bacteriocin. This is the first time that a bacteriocin produced in vivo by a human commensal bacterium was purified and characterized.
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Affiliation(s)
- E H Crost
- ISM2/BiosCiences UMR CNRS 6263, Interactions Moléculaires Microbiote - Muqueuse Intestinale, Service 342, Faculté des Sciences et Techniques de St Jérôme, Université Paul Cézanne Aix-Marseille III, Avenue Escadrille Normandie-Niemen, 13397 Marseille Cedex 20, France
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121
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Friedman M, Levin CE. Nutritional and medicinal aspects of D-amino acids. Amino Acids 2011; 42:1553-82. [PMID: 21519915 DOI: 10.1007/s00726-011-0915-1] [Citation(s) in RCA: 119] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2011] [Accepted: 04/06/2011] [Indexed: 02/07/2023]
Abstract
This paper reviews and interprets a method for determining the nutritional value of D-amino acids, D-peptides, and amino acid derivatives using a growth assay in mice fed a synthetic all-amino acid diet. A large number of experiments were carried out in which a molar equivalent of the test compound replaced a nutritionally essential amino acid such as L-lysine (L-Lys), L-methionine (L-Met), L-phenylalanine (L-Phe), and L-tryptophan (L-Trp) as well as the semi-essential amino acids L-cysteine (L-Cys) and L-tyrosine (L-Tyr). The results show wide-ranging variations in the biological utilization of test substances. The method is generally applicable to the determination of the biological utilization and safety of any amino acid derivative as a potential nutritional source of the corresponding L-amino acid. Because the organism is forced to use the D-amino acid or amino acid derivative as the sole source of the essential or semi-essential amino acid being replaced, and because a free amino acid diet allows better control of composition, the use of all-amino-acid diets for such determinations may be preferable to protein-based diets. Also covered are brief summaries of the widely scattered literature on dietary and pharmacological aspects of 27 individual D-amino acids, D-peptides, and isomeric amino acid derivatives and suggested research needs in each of these areas. The described results provide a valuable record and resource for further progress on the multifaceted aspects of D-amino acids in food and biological samples.
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Affiliation(s)
- Mendel Friedman
- Western Regional Research Center, Agricultural Research Service, United States Department of Agriculture, Albany, CA 94710, USA.
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122
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Abriouel H, Franz CMAP, Ben Omar N, Gálvez A. Diversity and applications of Bacillus bacteriocins. FEMS Microbiol Rev 2011; 35:201-32. [PMID: 20695901 DOI: 10.1111/j.1574-6976.2010.00244.x] [Citation(s) in RCA: 303] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Members of the genus Bacillus are known to produce a wide arsenal of antimicrobial substances, including peptide and lipopeptide antibiotics, and bacteriocins. Many of the Bacillus bacteriocins belong to the lantibiotics, a category of post-translationally modified peptides widely disseminated among different bacterial clades. Lantibiotics are among the best-characterized antimicrobial peptides at the levels of peptide structure, genetic determinants and biosynthesis mechanisms. Members of the genus Bacillus also produce many other nonmodified bacteriocins, some of which resemble the pediocin-like bacteriocins of the lactic acid bacteria (LAB), while others show completely novel peptide sequences. Bacillus bacteriocins are increasingly becoming more important due to their sometimes broader spectra of inhibition (as compared with most LAB bacteriocins), which may include Gram-negative bacteria, yeasts or fungi, in addition to Gram-positive species, some of which are known to be pathogenic to humans and/or animals. The present review provides a general overview of Bacillus bacteriocins, including primary structure, biochemical and genetic characterization, classification and potential applications in food preservation as natural preservatives and in human and animal health as alternatives to conventional antibiotics. Furthermore, it addresses their environmental applications, such as bioprotection against the pre- and post-harvest decay of vegetables, or as plant growth promoters.
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Affiliation(s)
- Hikmate Abriouel
- Departamento de Ciencias de la Salud, Área de Microbiología, Facultad de Ciencias Experimentales, Universidad de Jaén, Jaén, Spain
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123
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Brito M, Somkuti G, Renye J. Production of antilisterial bacteriocins by staphylococci isolated from bovine milk. J Dairy Sci 2011; 94:1194-200. [DOI: 10.3168/jds.2010-3849] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2010] [Accepted: 11/27/2010] [Indexed: 11/19/2022]
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124
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Mangoni ML, Carotenuto A, Auriemma L, Saviello MR, Campiglia P, Gomez-Monterrey I, Malfi S, Marcellini L, Barra D, Novellino E, Grieco P. Structure−Activity Relationship, Conformational and Biological Studies of Temporin L Analogues. J Med Chem 2011; 54:1298-307. [DOI: 10.1021/jm1012853] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Maria Luisa Mangoni
- Istituto Pasteur—Fondazione Cenci Bolognetti, Department of Biochemical Sciences, “A. Rossi Fanelli”, University of Rome “La Sapienza”, I-00185 Rome, Italy
| | - Alfonso Carotenuto
- Department of Pharmaceutical and Toxicological Chemistry, University of Naples “Federico II”, Via D. Montesano 49, I-80131 Naples, Italy
| | - Luigia Auriemma
- Department of Pharmaceutical and Toxicological Chemistry, University of Naples “Federico II”, Via D. Montesano 49, I-80131 Naples, Italy
| | - Maria Rosaria Saviello
- Department of Pharmaceutical and Toxicological Chemistry, University of Naples “Federico II”, Via D. Montesano 49, I-80131 Naples, Italy
| | - Pietro Campiglia
- Department of Pharmaceutical Science, University of Salerno, I-84084 Fisciano, Salerno, Italy
| | - Isabel Gomez-Monterrey
- Department of Pharmaceutical and Toxicological Chemistry, University of Naples “Federico II”, Via D. Montesano 49, I-80131 Naples, Italy
| | - Stefania Malfi
- Department of Pharmaceutical and Toxicological Chemistry, University of Naples “Federico II”, Via D. Montesano 49, I-80131 Naples, Italy
| | - Ludovica Marcellini
- Istituto Pasteur—Fondazione Cenci Bolognetti, Department of Biochemical Sciences, “A. Rossi Fanelli”, University of Rome “La Sapienza”, I-00185 Rome, Italy
| | - Donatella Barra
- Istituto Pasteur—Fondazione Cenci Bolognetti, Department of Biochemical Sciences, “A. Rossi Fanelli”, University of Rome “La Sapienza”, I-00185 Rome, Italy
| | - Ettore Novellino
- Department of Pharmaceutical and Toxicological Chemistry, University of Naples “Federico II”, Via D. Montesano 49, I-80131 Naples, Italy
| | - Paolo Grieco
- Department of Pharmaceutical and Toxicological Chemistry, University of Naples “Federico II”, Via D. Montesano 49, I-80131 Naples, Italy
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125
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Mutacins from Streptococcus mutans UA159 are active against multiple streptococcal species. Appl Environ Microbiol 2011; 77:2428-34. [PMID: 21296932 DOI: 10.1128/aem.02320-10] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Streptococcus mutans UA159, whose genome is completely sequenced, produces two nonlantibiotic mutacins, mutacin IV (encoded by nlmAB) and mutacin V (encoded by nlmC). In this study, we investigated the contribution of nlmA and nlmB to mutacin IV activity and demonstrated by performing genetic studies as well as by using semipurified molecules that, in contrast to a previous report, both of these genes are required for optimum mutacin IV activity. We also showed that mutacin IV is active against multiple Streptococcus species. In contrast, mutacin V displayed a narrower inhibitory range than mutacin IV. Our results suggest that mutacin IV and mutacin V may act synergistically to inhibit various organisms.
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126
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Wijnker JJ, Weerts EAWS, Breukink EJ, Houben JH, Lipman LJA. Reduction of Clostridium sporogenes spore outgrowth in natural sausage casings using nisin. Food Microbiol 2011; 28:974-9. [PMID: 21569941 DOI: 10.1016/j.fm.2011.01.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2010] [Revised: 12/22/2010] [Accepted: 01/22/2011] [Indexed: 10/18/2022]
Abstract
Preservation of natural sausage casings using dry salt or saturated brine is regarded as sufficient to inactivate vegetative pathogenic non-spore-forming bacteria present on the casings. Although the outgrowth of bacterial spores is prevented by salt or saturated brine preservation, these spores will remain present and develop into vegetative cells when conditions are more favourable. To prevent subsequent outgrowth additional preservation measures should be implemented. In the experiments described the use of nisin was evaluated to reduce outgrowth of spores in desalinated casings. The bacteriocin nisin was chosen because of its known efficacy against spore-forming bacteria and their spores in various foodstuffs. Clostridium spore suspensions (Clostridium sporogenes, ATCC 3584) were used in two concentrations to inoculate three nisin concentrations (10, 50, 100 μg/mL) in water containing gamma-irradiated casings. Additionally, the binding of nisin to casings, using (14)C-labeled nisin Z and subsequent availability of nisin were evaluated. Results demonstrate that nisin is partly reversibly bound to casings and can reduce the outgrowth of Clostridium spores in the model used by approximately 1 log(10) (90%). However, the biological relevance of these results needs to be determined further by conducting industrial trials before any recommendation can be made on the practical implementation of nisin in the preservation of natural sausage casings.
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Affiliation(s)
- J J Wijnker
- Institute for Risk Assessment Sciences, Division Veterinary Public Health, PO Box 80.175, NL-3508 TD, Utrecht University, The Netherlands.
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127
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Al-Mahrous MM, Upton M. Discovery and development of lantibiotics; antimicrobial agents that have significant potential for medical application. Expert Opin Drug Discov 2011; 6:155-70. [PMID: 22647134 DOI: 10.1517/17460441.2011.545387] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
INTRODUCTION Antimicrobial drug resistance is driving the need for novel therapeutics. Amongst the most promising antibacterial agents that are being investigated as replacements for current therapeutic antibiotics are antibacterial peptides, such as the lanthionine-containing peptide antibiotics (lantibiotics). AREAS COVERED This review focuses on the current methods used for discovery of potentially exploitable lantibiotics for medical applications and discusses relevant recent innovations that will have a positive impact on the discovery of useful lantibiotics. EXPERT OPINION Recent technological advances in a number of fields mean that increased research into the identification and characterisation of new lantibiotics is feasible. We need to increase our understanding of the various mechanisms of antibacterial action exhibited by lantibiotics and apply this knowledge to peptide engineering or novel practical applications. The advent of next-generation sequencing approaches now negate the need for extensive reverse genetics and employment of bioinformatics approaches is greatly assisting the identification of potentially useful inhibitors in the genomes of a range of clinically significant bacteria. These advances in genetic analysis and engineering will facilitate increased exploitation of lantibiotics in medical therapy.
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Affiliation(s)
- Mohammed M Al-Mahrous
- University of Manchester, School of Translational Medicine, Department of Medical Microbiology, Clinical Sciences Building, Manchester Royal Infirmary, Oxford Road, Manchester, M13 9WL, UK +44 1 161 276 8828 ; +44 0 161 276 8826 ;
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128
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Yoon JI, Bajpai VK, Kang SC. Synergistic effect of nisin and cone essential oil of Metasequoia glyptostroboides Miki ex Hu against Listeria monocytogenes in milk samples. Food Chem Toxicol 2011; 49:109-14. [DOI: 10.1016/j.fct.2010.10.004] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2010] [Revised: 08/27/2010] [Accepted: 10/02/2010] [Indexed: 10/19/2022]
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129
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Kabuki T, Kawai Y, Uenishi H, Seto Y, Kok J, Nakajima H, Saito T. Gene cluster for biosynthesis of thermophilin 1277 - a lantibiotic produced by Streptococcus thermophilus SBT1277, and heterologous expression of TepI, a novel immunity peptide. J Appl Microbiol 2010; 110:641-9. [DOI: 10.1111/j.1365-2672.2010.04914.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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130
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Abstract
Persisters are dormant variants of regular cells that form stochastically in microbial populations and are highly tolerant to antibiotics. High persister (hip) mutants of Pseudomonas aeruginosa are selected in patients with cystic fibrosis. Similarly, hip mutants of Candida albicans are selected in patients with an oral thrush biofilm. These observations suggest that persisters may be the main culprit responsible for the recalcitrance of chronic infectious disease to antimicrobial therapy. Screening knockout libraries has not produced mutants lacking persisters, indicating that dormancy mechanisms are redundant. Toxin/antitoxin (TA) modules are involved in persister formation in Escherichia coli. The SOS response leads to overexpression of the TisB toxin and persister formation. TisB is a membrane-acting peptide that apparently sends cells into dormancy by decreasing the proton motive force and ATP levels. Stress responses may act as general activators of persister formation. Proteins required for maintaining persisters may represent realistic targets for discovery of drugs capable of effectively treating chronic infections.
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Affiliation(s)
- Kim Lewis
- Department of Biology and Antimicrobial Discovery Center, Northeastern University, Boston, Massachusetts 02115, USA.
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131
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Abstract
Most bacteria in nature exist in multispecies communities known as biofilms. In the natural habitat where resources (nutrient, space, etc.) are usually limited, individual species must compete or collaborate with other neighboring species in order to perpetuate in the multispecies community. The human oral cavity is colonized by >700 microbial species known as the indigenous microflora. This indigenous flora normally maintains an ecological balance through antagonistic as well as mutualistic interspecies interactions. However, environmental perturbation may disrupt this balance, leading to overgrowth of pathogenic species, which could in turn initiate diseases such as dental caries (tooth decay) and periodontitis (gum disease). Understanding the mechanisms of diversity maintenance may help development of novel approaches to manage these "polymicrobial diseases." In this chapter, we will focus on a well-characterized form of biochemical warfare: bacteriocins produced by Streptococcus mutans, a primary dental caries pathogen, and H(2)O(2) produced by Streptococcus sanguinis, an oral commensal. We will describe detailed methodologies on the competition assay, isolation, purification, and characterization of bacteriocins.
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132
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Nanofibers offer alternative ways to the treatment of skin infections. J Biomed Biotechnol 2010; 2010. [PMID: 20798871 PMCID: PMC2926677 DOI: 10.1155/2010/510682] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2010] [Accepted: 06/08/2010] [Indexed: 11/17/2022] Open
Abstract
Injury to the skin causes a breach in the protective layer surrounding the body. Many pathogens are resistant to antibiotics, rendering conventional treatment less effective. This led to the use of alternative antimicrobial compounds, such as silver ions, in skin treatment. In this review nanofibers, and the incorporation of natural antimicrobial compounds in these scaffolds, are discussed as an alternative way to control skin infections. Electrospinning as a technique to prepare nanofibers is discussed. The possibility of using these structures as drug delivery systems is investigated.
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133
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Friedman M. Origin, Microbiology, Nutrition, and Pharmacology of D-Amino Acids. Chem Biodivers 2010; 7:1491-530. [DOI: 10.1002/cbdv.200900225] [Citation(s) in RCA: 142] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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134
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Improvement of multiple-stress tolerance and lactic acid production in Lactococcus lactis NZ9000 under conditions of thermal stress by heterologous expression of Escherichia coli DnaK. Appl Environ Microbiol 2010; 76:4277-85. [PMID: 20453133 DOI: 10.1128/aem.02878-09] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The effects of nisin-induced dnaK expression in Lactococcus lactis were examined, and this expression was shown to improve stress tolerance and lactic acid fermentation efficiency. Using a nisin-inducible expression system, DnaK proteins from L. lactis (DnaK(Lla)) and Escherichia coli (DnaK(Eco)) were produced in L. lactis NZ9000. In comparison to a strain harboring the empty vector pNZ8048 (designated NZ-Vector) and one expressing dnaK(Lla) (designated NZ-LDnaK), the dnaK(Eco)-expressing strain, named NZ-EDnaK, exhibited more tolerance to heat stress at 40 degrees C in GM17 liquid medium. The cell viability of NZ-Vector was reduced 4.6-fold after 6 h of heat treatment. However, NZ-EDnaK showed 13.5-fold increased viability under these conditions, with a very low concentration of DnaK(Eco) production. Although the heterologous expression of dnaK(Eco) did not effect DnaK(Lla) production, heat treatment increased the DnaK(Lla) level 3.5- and 3.6-fold in NZ-Vector and NZ-EDnaK, respectively. Moreover, NZ-EDnaK showed tolerance to multiple stresses, including 3% NaCl, 5% ethanol, and 0.5% lactic acid (pH 5.47). In CMG medium, the lactate yield and the maximum lactate productivity of NZ-EDnaK were higher than the corresponding values for NZ-Vector at 30 degrees C. Interestingly, at 40 degrees C, these values of NZ-EDnaK were not significantly different from the corresponding values for the control strain at 30 degrees C. Lactate dehydrogenase (LDH) activity was also found to be stable at 40 degrees C in the presence of DnaK(Eco). These findings suggest that the heterologous expression of dnaK(Eco) enhances the quality control of proteins and enzymes, resulting in improved growth and lactic acid fermentation at high temperature.
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135
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Cundliffe E, Demain AL. Avoidance of suicide in antibiotic-producing microbes. J Ind Microbiol Biotechnol 2010; 37:643-72. [PMID: 20446033 DOI: 10.1007/s10295-010-0721-x] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2010] [Accepted: 03/30/2010] [Indexed: 11/29/2022]
Abstract
Many microbes synthesize potentially autotoxic antibiotics, mainly as secondary metabolites, against which they need to protect themselves. This is done in various ways, ranging from target-based strategies (i.e. modification of normal drug receptors or de novo synthesis of the latter in drug-resistant form) to the adoption of metabolic shielding and/or efflux strategies that prevent drug-target interactions. These self-defence mechanisms have been studied most intensively in antibiotic-producing prokaryotes, of which the most prolific are the actinomycetes. Only a few documented examples pertain to lower eukaryotes while higher organisms have hardly been addressed in this context. Thus, many plant alkaloids, variously described as herbivore repellents or nitrogen excretion devices, are truly antibiotics-even if toxic to humans. As just one example, bulbs of Narcissus spp. (including the King Alfred daffodil) accumulate narciclasine that binds to the larger subunit of the eukaryotic ribosome and inhibits peptide bond formation. However, ribosomes in the Amaryllidaceae have not been tested for possible resistance to narciclasine and other alkaloids. Clearly, the prevalence of suicide avoidance is likely to extend well beyond the remit of the present article.
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Affiliation(s)
- Eric Cundliffe
- Department of Biochemistry, University of Leicester, Leicester, LE1 9HN, UK.
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136
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Dörr T, Vulić M, Lewis K. Ciprofloxacin causes persister formation by inducing the TisB toxin in Escherichia coli. PLoS Biol 2010; 8:e1000317. [PMID: 20186264 PMCID: PMC2826370 DOI: 10.1371/journal.pbio.1000317] [Citation(s) in RCA: 534] [Impact Index Per Article: 38.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2009] [Accepted: 01/20/2010] [Indexed: 11/18/2022] Open
Abstract
Bacteria induce stress responses that protect the cell from lethal factors such as DNA-damaging agents. Bacterial populations also form persisters, dormant cells that are highly tolerant to antibiotics and play an important role in recalcitrance of biofilm infections. Stress response and dormancy appear to represent alternative strategies of cell survival. The mechanism of persister formation is unknown, but isolated persisters show increased levels of toxin/antitoxin (TA) transcripts. We have found previously that one or more components of the SOS response induce persister formation after exposure to a DNA-damaging antibiotic. The SOS response induces several TA genes in Escherichia coli. Here, we show that a knockout of a particular SOS-TA locus, tisAB/istR, had a sharply decreased level of persisters tolerant to ciprofloxacin, an antibiotic that causes DNA damage. Step-wise administration of ciprofloxacin induced persister formation in a tisAB-dependent manner, and cells producing TisB toxin were tolerant to multiple antibiotics. TisB is a membrane peptide that was shown to decrease proton motive force and ATP levels, consistent with its role in forming dormant cells. These results suggest that a DNA damage-induced toxin controls production of multidrug tolerant cells and thus provide a model of persister formation.
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Affiliation(s)
- Tobias Dörr
- Antimicrobial Discovery Center, Department of Biology, Northeastern University, Boston, Massachusetts, United States of America
| | - Marin Vulić
- Antimicrobial Discovery Center, Department of Biology, Northeastern University, Boston, Massachusetts, United States of America
| | - Kim Lewis
- Antimicrobial Discovery Center, Department of Biology, Northeastern University, Boston, Massachusetts, United States of America
- * E-mail:
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137
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Inactivation of Salmonella Enteritidis strains by combination of high hydrostatic pressure and nisin. Int J Food Microbiol 2010; 140:49-56. [PMID: 20226554 DOI: 10.1016/j.ijfoodmicro.2010.02.010] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2009] [Revised: 02/08/2010] [Accepted: 02/10/2010] [Indexed: 11/24/2022]
Abstract
The effects of high hydrostatic pressure (HHP) and nisin treatment alone and in combination on cellular components and viability of two Salmonella enterica subsp. enterica serovar Enteritidis (S. Enteritidis) strains were evaluated by differential scanning calorimetry (DSC) and plate counting in order to evaluate the relative resistance and optimize the treatment conditions. S. Enteritidis FDA and OSU 799 strains were subjected to HHP (0.1-550 MPa for 10 min at 25 degrees C) alone and in combination with nisin (200 IU/ml nisin) in culture broth. HHP (up to 200 MPa) or the nisin alone did not affect the viability and cellular components of either strain. An 8-log cfu/ml reduction was observed after a pressure treatment at 500 MPa for the FDA strain and 450 MPa for the OSU 799 strain. When nisin was added, a similar reduction was obtained at 400 MPa for FDA strain and 350 MPa for the OSU 799 strain. The decrease in apparent enthalpy appeared to be mainly due to reduction in the ribosome denaturation peak for both the pressure alone and the pressure-nisin combination treatments. HHP facilitated penetration of nisin into the cell above 100 MPa pressure. Monitoring through DNA-binding probes the effect of pressure and nisin treatments on DNA in vivo showed that nisin did not affect DNA at 200 IU/ml. The apparent enthalpy data obtained from DSC can be used for optimization of pressure levels to reduce a microbial population in the presence of nisin.
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138
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Schneider T, Sahl HG. An oldie but a goodie - cell wall biosynthesis as antibiotic target pathway. Int J Med Microbiol 2009; 300:161-9. [PMID: 20005776 DOI: 10.1016/j.ijmm.2009.10.005] [Citation(s) in RCA: 179] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
Bacterial cell wall biosynthesis represents the target pathway for penicillin, the first antibiotic that was clinically applied on a large scale. Penicillin, by means of its beta-lactam ring, inhibits a number of enzymes which participate in inserting monomeric cell wall building blocks into the cell wall polymer and which have been termed penicillin-binding proteins (PBPs). Ever since the introduction of penicillin, hundreds of beta-lactam antibiotics have been developed and details of their molecular activities elaborated. Meanwhile, various additional classes of antibiotics have been described, which inhibit the same pathway, yet use target molecules others than the PBPs. Such classes include the glycopeptide antibiotics, lipopeptide and lipodepsipeptide antibiotics, the lantibiotics and various other natural product antibiotics with comparatively complex structures. They usually target the membrane-bound steps of the biosynthesis pathway and the highly conserved lipid-bound intermediates of the building block such as lipid II, which represents a particular "Achilles' heel" for antibiotic attack. With in-depth analysis of the activity of more recently identified inhibitors and with the availability of novel techniques for studying prokaryotic cell biology, new insights were obtained into the molecular organisation of the cell wall biosynthesis machinery and its interconnections with other vital cellular processes such as cell division. This, in turn, provides hints for new targets to be exploited and for the development of novel cell wall biosynthesis inhibitors.
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Affiliation(s)
- Tanja Schneider
- Institute of Medical Microbiology, Immunology and Parasitology-Pharmaceutical Microbiology Section, University of Bonn, Meckenheimer Allee 168, D-53115 Bonn, Germany
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139
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Expression of a synthesized gene encoding cationic peptide cecropin B in transgenic tomato plants protects against bacterial diseases. Appl Environ Microbiol 2009; 76:769-75. [PMID: 19966019 DOI: 10.1128/aem.00698-09] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The cationic lytic peptide cecropin B (CB), isolated from the giant silk moth (Hyalophora cecropia), has been shown to effectively eliminate Gram-negative and some Gram-positive bacteria. In this study, the effects of chemically synthesized CB on plant pathogens were investigated. The S(50)s (the peptide concentrations causing 50% survival of a pathogenic bacterium) of CB against two major pathogens of the tomato, Ralstonia solanacearum and Xanthomonas campestris pv. vesicatoria, were 529.6 microg/ml and 0.29 microg/ml, respectively. The CB gene was then fused to the secretory signal peptide (sp) sequence from the barley alpha-amylase gene, and the new construct, pBI121-spCB, was used for the transformation of tomato plants. Integration of the CB gene into the tomato genome was confirmed by PCR, and its expression was confirmed by Western blot analyses. In vivo studies of the transgenic tomato plant demonstrated significant resistance to bacterial wilt and bacterial spot. The levels of CB expressed in transgenic tomato plants ( approximately 0.05 microg in 50 mg of leaves) were far lower than the S(50) determined in vitro. CB transgenic tomatoes could therefore be a new mode of bioprotection against these two plant diseases with significant agricultural applications.
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140
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The large mechanosensitive channel MscL determines bacterial susceptibility to the bacteriocin sublancin 168. Antimicrob Agents Chemother 2009; 53:4702-11. [PMID: 19738010 DOI: 10.1128/aac.00439-09] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bacillus subtilis strain 168 produces the extremely stable and broad-spectrum lantibiotic sublancin 168. Known sublancin 168-susceptible organisms include important pathogens, such as Staphylococcus aureus. Nevertheless, since its discovery, the mode of action of sublancin 168 has remained elusive. The present studies were, therefore, aimed at the identification of cellular determinants for bacterial susceptibility toward sublancin 168. Growth inhibition and competition assays on plates and in liquid cultures revealed that sublancin 168-mediated growth inhibition of susceptible B. subtilis and S. aureus cells is affected by the NaCl concentration in the growth medium. Added NaCl did not influence the production, activity, or stability of sublancin 168 but, instead, lowered the susceptibility of sensitive cells toward this lantibiotic. Importantly, the susceptibility of B. subtilis and S. aureus cells toward sublancin 168 was shown to depend on the presence of the large mechanosensitive channel of conductance MscL. In contrast, MscL was not involved in susceptibility toward the bacteriocin nisin or Pep5. Taken together, our unprecedented results demonstrate that MscL is a critical and specific determinant in bacterial sublancin 168 susceptibility that may serve either as a direct target for this lantibiotic or as a gate of entry to the cytoplasm.
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141
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Sturla L, Fresia C, Guida L, Bruzzone S, Scarfì S, Usai C, Fruscione F, Magnone M, Millo E, Basile G, Grozio A, Jacchetti E, Allegretti M, De Flora A, Zocchi E. LANCL2 is necessary for abscisic acid binding and signaling in human granulocytes and in rat insulinoma cells. J Biol Chem 2009; 284:28045-28057. [PMID: 19667068 DOI: 10.1074/jbc.m109.035329] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Abscisic acid (ABA) is a plant hormone regulating fundamental physiological functions in plants, such as response to abiotic stress. Recently, ABA was shown to be produced and released by human granulocytes, by insulin-producing rat insulinoma cells, and by human and murine pancreatic beta cells. ABA autocrinally stimulates the functional activities specific for each cell type through a receptor-operated signal transduction pathway, sequentially involving a pertussis toxin-sensitive receptor/G-protein complex, cAMP, CD38-produced cADP-ribose and intracellular calcium. Here we show that the lanthionine synthetase C-like protein LANCL2 is required for ABA binding on the membrane of human granulocytes and that LANCL2 is necessary for transduction of the ABA signal into the cell-specific functional responses in granulocytes and in rat insulinoma cells. Co-expression of LANCL2 and CD38 in the human HeLa cell line reproduces the ABA-signaling pathway. Results obtained with granulocytes and CD38(+)/LANCL2(+) HeLa transfected with a chimeric G-protein (G alpha(q/i)) suggest that the pertussis toxin-sensitive G-protein coupled to LANCL2 is a G(i). Identification of LANCL2 as a critical component of the ABA-sensing protein complex will enable the screening of synthetic ABA antagonists as prospective new anti-inflammatory and anti-diabetic agents.
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Affiliation(s)
- Laura Sturla
- Department of Experimental Medicine, Section of Biochemistry, and Center of Excellence for Biomedical Research, University of Genova, Viale Benedetto XV 1, Genova 16132
| | - Chiara Fresia
- Department of Experimental Medicine, Section of Biochemistry, and Center of Excellence for Biomedical Research, University of Genova, Viale Benedetto XV 1, Genova 16132
| | - Lucrezia Guida
- Department of Experimental Medicine, Section of Biochemistry, and Center of Excellence for Biomedical Research, University of Genova, Viale Benedetto XV 1, Genova 16132
| | - Santina Bruzzone
- Department of Experimental Medicine, Section of Biochemistry, and Center of Excellence for Biomedical Research, University of Genova, Viale Benedetto XV 1, Genova 16132
| | - Sonia Scarfì
- Department of Experimental Medicine, Section of Biochemistry, and Center of Excellence for Biomedical Research, University of Genova, Viale Benedetto XV 1, Genova 16132; Advanced Biotechnology Center, Largo R. Benzi 10, Genova 16132
| | - Cesare Usai
- Institute of Biophysics, National Research Council, Via De Marini 6, Genova 16149
| | | | - Mirko Magnone
- Department of Experimental Medicine, Section of Biochemistry, and Center of Excellence for Biomedical Research, University of Genova, Viale Benedetto XV 1, Genova 16132
| | - Enrico Millo
- Department of Experimental Medicine, Section of Biochemistry, and Center of Excellence for Biomedical Research, University of Genova, Viale Benedetto XV 1, Genova 16132
| | - Giovanna Basile
- Department of Experimental Medicine, Section of Biochemistry, and Center of Excellence for Biomedical Research, University of Genova, Viale Benedetto XV 1, Genova 16132
| | - Alessia Grozio
- Department of Experimental Medicine, Section of Biochemistry, and Center of Excellence for Biomedical Research, University of Genova, Viale Benedetto XV 1, Genova 16132
| | - Emanuela Jacchetti
- Institute of Biophysics, National Research Council, Via De Marini 6, Genova 16149
| | | | - Antonio De Flora
- Department of Experimental Medicine, Section of Biochemistry, and Center of Excellence for Biomedical Research, University of Genova, Viale Benedetto XV 1, Genova 16132.
| | - Elena Zocchi
- Department of Experimental Medicine, Section of Biochemistry, and Center of Excellence for Biomedical Research, University of Genova, Viale Benedetto XV 1, Genova 16132; Advanced Biotechnology Center, Largo R. Benzi 10, Genova 16132.
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142
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Appleyard AN, Choi S, Read DM, Lightfoot A, Boakes S, Hoffmann A, Chopra I, Bierbaum G, Rudd BA, Dawson MJ, Cortes J. Dissecting structural and functional diversity of the lantibiotic mersacidin. ACTA ACUST UNITED AC 2009; 16:490-8. [PMID: 19477413 PMCID: PMC2706954 DOI: 10.1016/j.chembiol.2009.03.011] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2008] [Revised: 03/02/2009] [Accepted: 03/10/2009] [Indexed: 12/04/2022]
Abstract
Mersacidin is a tetracyclic lantibiotic with antibacterial activity against Gram-positive pathogens. To probe the specificity of the biosynthetic pathway of mersacidin and obtain analogs with improved antibacterial activity, an efficient system for generating variants of this lantibiotic was developed. A saturation mutagenesis library of the residues of mersacidin not involved in cycle formation was constructed and used to validate this system. Mersacidin analogs were obtained in good yield in approximately 35% of the cases, producing a collection of 82 new compounds. This system was also used for the production of deletion and insertion mutants of mersacidin. The outcome of these studies suggests that this system can be extended to produce mersacidin variants with multiple changes that will allow a full investigation of the potential use of modified mersacidins as therapeutic agents.
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Affiliation(s)
- Antony N. Appleyard
- Novacta Biosystems Ltd., BioPark Hertfordshire, Welwyn Garden City, Hertfordshire AL7 3AX, UK
| | - Shaila Choi
- Novacta Biosystems Ltd., BioPark Hertfordshire, Welwyn Garden City, Hertfordshire AL7 3AX, UK
| | - Daniel M. Read
- Novacta Biosystems Ltd., BioPark Hertfordshire, Welwyn Garden City, Hertfordshire AL7 3AX, UK
| | - Ann Lightfoot
- Novacta Biosystems Ltd., BioPark Hertfordshire, Welwyn Garden City, Hertfordshire AL7 3AX, UK
- Antimicrobial Research Centre and Institute of Molecular and Cellular Biology, University of Leeds, Leeds LS2 9JT, UK
| | - Steven Boakes
- Novacta Biosystems Ltd., BioPark Hertfordshire, Welwyn Garden City, Hertfordshire AL7 3AX, UK
| | - Anja Hoffmann
- Institut für Medizinische Mikrobiologie und Immunologie, Universität Bonn, 53105 Bonn, Germany
| | - Ian Chopra
- Antimicrobial Research Centre and Institute of Molecular and Cellular Biology, University of Leeds, Leeds LS2 9JT, UK
| | - Gabriele Bierbaum
- Institut für Medizinische Mikrobiologie und Immunologie, Universität Bonn, 53105 Bonn, Germany
| | - Brian A.M. Rudd
- Novacta Biosystems Ltd., BioPark Hertfordshire, Welwyn Garden City, Hertfordshire AL7 3AX, UK
| | - Michael J. Dawson
- Novacta Biosystems Ltd., BioPark Hertfordshire, Welwyn Garden City, Hertfordshire AL7 3AX, UK
| | - Jesus Cortes
- Novacta Biosystems Ltd., BioPark Hertfordshire, Welwyn Garden City, Hertfordshire AL7 3AX, UK
- Corresponding author
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143
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Morris RP, Leeds JA, Naegeli HU, Oberer L, Memmert K, Weber E, LaMarche MJ, Parker CN, Burrer N, Esterow S, Hein AE, Schmitt EK, Krastel P. Ribosomally synthesized thiopeptide antibiotics targeting elongation factor Tu. J Am Chem Soc 2009; 131:5946-55. [PMID: 19338336 DOI: 10.1021/ja900488a] [Citation(s) in RCA: 157] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We identified the thiomuracins, a novel family of thiopeptides produced by a rare-actinomycete bacterium typed as a Nonomuraea species, via a screen for inhibition of growth of the bacterial pathogen Staphylococcus aureus. Thiopeptides are a class of macrocyclic, highly modified peptides that are decorated by thiazoles and defined by a central six-membered heterocyclic ring system. Mining the genomes of thiopeptide-producing strains revealed the elusive biosynthetic route for this class of antibiotics. The thiopeptides are chromosomally encoded, ribosomally synthesized proteins, and isolation of gene clusters for production of thiomuracin and the related thiopeptide GE2270A revealed the post-translational machinery required for maturation. The target of the thiomuracins was identified as bacterial Elongation Factor Tu (EF-Tu). In addition to potently inhibiting a target that is unexploited by marketed human therapeutics, the thiomuracins have a low propensity for selecting for antibiotic resistance and confer no measurable cross-resistance to antibiotics in clinical use.
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Affiliation(s)
- Rowan P Morris
- Natural Products Unit, Novartis Institutes for BioMedical Research, Basel, 4056, Switzerland
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144
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Piper C, Draper LA, Cotter PD, Ross RP, Hill C. A comparison of the activities of lacticin 3147 and nisin against drug-resistant Staphylococcus aureus and Enterococcus species. J Antimicrob Chemother 2009; 64:546-51. [PMID: 19561147 DOI: 10.1093/jac/dkp221] [Citation(s) in RCA: 118] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
OBJECTIVES Our goal was to compare the activities of lacticin 3147 and nisin, two of the most well characterized lantibiotics, against antibiotic-resistant staphylococci and enterococci. METHODS We determined the MICs of lacticin 3147 and nisin for 20 strains of methicillin-resistant Staphylococcus aureus (MRSA), 20 strains of vancomycin-resistant enterococci (VRE), 6 strains of S. aureus with intermediate resistance to vancomycin (VISA), 5 strains of heterogeneous vancomycin-intermediate S. aureus (hVISA) and 4 strains of S. aureus that are susceptible to methicillin. RESULTS Lacticin 3147 displayed potent activity against VRE with MIC values between 1.9 and 7.7 mg/L, and varying levels of activity against S. aureus strains (MRSA, 1.9-15.4 mg/L; laboratory strains, >or=15.4 mg/L; hVISA, 15.4-30.9 mg/L; VISA, >or=61.8 mg/L). Nisin was more active against the S. aureus strains in general (MRSA and laboratory strains, 0.5-4.1 mg/L; VISA and hVISA, 2 to >or=8.3 mg/L), but was less effective than lacticin 3147 against VRE (2 to >or=8.3 mg/L). CONCLUSIONS Nisin is more effective against S. aureus whereas lacticin 3147 possesses greater potency against VRE. The modifications responsible for the vancomycin-resistant phenotypes of hVISA and VISA strains also provide protection against the two lantibiotics.
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Affiliation(s)
- Clare Piper
- Department of Microbiology, University College Cork, College Road, Cork, Ireland
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145
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Carvalho ADO, Gomes VM. Plant defensins--prospects for the biological functions and biotechnological properties. Peptides 2009; 30:1007-20. [PMID: 19428780 DOI: 10.1016/j.peptides.2009.01.018] [Citation(s) in RCA: 165] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2008] [Revised: 01/22/2009] [Accepted: 01/26/2009] [Indexed: 01/07/2023]
Abstract
Plant defensins are a prominent family of cationic peptides in the plant kingdom. They are structurally and functionally related to defensins that have been previously characterized in mammals and insects. They present molecular masses between 5 and 7kDa and possess a pattern of eight conserved Cys residues. The three-dimensional structure of plant defensins is small and globular. It has three anti-parallel beta-sheets and one alpha-helix that is stabilized by a structural motif composed of disulfide bridges. This motif is found in other peptides with biological activity and is called the Cys stabilized alphabeta motif (CSalphabeta). Based on the growing knowledge on defensin structure, gene expression and regulation, and also their in vitro biological activity, it has become clear that plant defensins are complex and sophisticated peptides whose function extends beyond their role in defense of plants against microbial infection. This review discusses recent data and will present comprehensive information regarding the study of defensins.
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Affiliation(s)
- André de Oliveira Carvalho
- Laboratório de Fisiologia e Bioquímica de Microrganismos, Centro de Biociências e Biotecnologia, Universidade Estadual do Norte Fluminense-Darcy Ribeiro, Campos dos Goytacazes-RJ, Brazil.
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146
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Rihakova J, Petit VW, Demnerova K, Prévost H, Rebuffat S, Drider D. Insights into structure-activity relationships in the C-terminal region of divercin V41, a class IIa bacteriocin with high-level antilisterial activity. Appl Environ Microbiol 2009; 75:1811-9. [PMID: 19181835 PMCID: PMC2663188 DOI: 10.1128/aem.02266-08] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2008] [Accepted: 01/16/2009] [Indexed: 11/20/2022] Open
Abstract
Divercin V41 (DvnV41) is a class IIa bacteriocin with potent antilisterial activity isolated from Carnobacterium divergens V41. Previously, we expressed from a synthetic gene, in Escherichia coli Origami, a recombinant DvnV41 designated DvnRV41, which possesses four additional amino acids (AMDP) in the N-terminal region that result from enzymatic cleavage and retains the initial DvnV41 activity. To unravel the relationship between the structure of DvnRV41 and its particularly elevated activity, we produced by site-directed mutagenesis eight variants in which a single amino acid replacement was specifically introduced into the sequence. The point mutations were designed to change either conserved residues in class IIa bacteriocins or residues specific to DvnV41 located mainly in the C-terminal region. The fusion proteins were purified from the cytosoluble fractions by immobilized affinity chromatography. DvnRV41 and its variants were released from the fusion proteins by enzymatic cleavage, using enterokinase. The purity of DvnRV41 and of the variants was checked by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, high-performance liquid chromatography, and mass spectrometry. The antibacterial activity of DvnRV41 and its variants was assessed using different indicator strains, including Listeria monocytogenes EGDe and Enterococcus faecalis JH2-2. The activity of all of the variants appeared to be less than the activity of DvnRV41. The decrease in activity did not appear to be related to a global conformational change, as determined by circular dichroism. Overall, the variants of DvnRV41 produced in the present study provide interesting insights into structure-activity relationships of class IIa bacteriocins.
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Affiliation(s)
- Jitka Rihakova
- UMR INRA SECALIM 1014 ENITIAA-ENVN, Rue de la Géraudière, BP 82225, 44322 Nantes Cedex 3, France
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147
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Todorov SD. Bacteriocins from Lactobacillus plantarum - production, genetic organization and mode of action: produção, organização genética e modo de ação. Braz J Microbiol 2009; 40:209-21. [PMID: 24031346 PMCID: PMC3769724 DOI: 10.1590/s1517-83822009000200001] [Citation(s) in RCA: 112] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2008] [Revised: 09/29/2008] [Accepted: 02/14/2009] [Indexed: 11/30/2022] Open
Abstract
Bacteriocins are biologically active proteins or protein complexes that display a bactericidal mode of action towards usually closely related species. Numerous strains of bacteriocin producing Lactobacillus plantarum have been isolated in the last two decades from different ecological niches including meat, fish, fruits, vegetables, and milk and cereal products. Several of these plantaricins have been characterized and the aminoacid sequence determined. Different aspects of the mode of action, fermentation optimization and genetic organization of the bacteriocin operon have been studied. However, numerous of bacteriocins produced by different Lactobacillus plantarum strains have not been fully characterized. In this article, a brief overview of the classification, genetics, characterization, including mode of action and production optimization for bacteriocins from Lactic Acid Bacteria in general, and where appropriate, with focus on bacteriocins produced by Lactobacillus plantarum, is presented.
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Affiliation(s)
- Svetoslav D Todorov
- Department of Microbiology, University of Stellenbosch , 7600 Stellenbosch , South Africa
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148
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Nguyen T, Zhang Z, Huang IH, Wu C, Merritt J, Shi W, Qi F. Genes involved in the repression of mutacin I production in Streptococcus mutans. MICROBIOLOGY-SGM 2009; 155:551-556. [PMID: 19202103 DOI: 10.1099/mic.0.021303-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Streptococcus mutans is considered a primary pathogen for human dental caries. Its ability to produce a variety of peptide antibiotics called mutacins may play an important role in its invasion and establishment in the dental biofilm. S. mutans strain UA140 produces two types of mutacins, the lantibiotic mutacin I and the non-lantibiotic mutacin IV. In a previous study, we constructed a random insertional-mutation library to screen for genes involved in regulating mutacin I production, and found 25 genes/operons that have a positive effect on mutacin I production. In this study, we continued our previous work to identify genes that are negatively involved in mutacin I production. By using a high-phosphate brain heart infusion agar medium that inhibited mutacin I production of the wild-type, we isolated 77 clones that consistently produced mutacin I under repressive conditions. From the 34 clones for which we were able to obtain a sequence, 17 unique genes were identified. These genes encompass a variety of functional groups, including central metabolism, surface binding and sugar transport, and unknown functions. Some of the 17 mutations were further characterized and shown to increase mutacin gene expression during growth when the gene is usually not expressed in the wild-type. These results further demonstrate an intimate and intricate connection between mutacin production and the overall cellular homeostasis.
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Affiliation(s)
- Trang Nguyen
- UCLA School of Dentistry, Los Angeles, CA 90095, USA
| | - Zhijun Zhang
- College of Dentistry, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73034, USA
| | - I-Hsiu Huang
- College of Dentistry, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73034, USA
| | - Chenggang Wu
- College of Dentistry, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73034, USA
| | - Justin Merritt
- College of Dentistry, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73034, USA
| | - Wenyuan Shi
- UCLA School of Dentistry, Los Angeles, CA 90095, USA
| | - Fengxia Qi
- College of Dentistry, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73034, USA
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149
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Loughman JA, Fritz SA, Storch GA, Hunstad DA. Virulence gene expression in human community-acquired Staphylococcus aureus infection. J Infect Dis 2009; 199:294-301. [PMID: 19115951 DOI: 10.1086/595982] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Isolates of methicillin-resistant Staphylococcus aureus (MRSA) were once linked uniformly with hospital-associated infections; however, community-acquired MRSA (CA-MRSA) now represents an emerging threat worldwide. To examine the association of differential virulence gene expression with outcomes of human infection, we measured transcript levels of target staphylococcal genes directly in clinical samples from children with active known or suspected CA-MRSA infections. Virulence genes encoding secreted toxins, including Panton-Valentine leukocidin, were highly expressed during superficial and invasive CA-MRSA infections. In contrast, increased expression of surface-associated protein A was linked only with invasive disease. Comparisons with laboratory-grown corresponding clinical isolates revealed that tissue-specific expression profiles reflect the activity of the staphylococcal accessory gene regulator during human infection. These results represent the first demonstration of staphylococcal gene expression and regulation directly in human tissue. Such analysis will help to unravel the complex interactions between CA-MRSA and its host environmental niches during disease development.
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Affiliation(s)
- Jennifer A Loughman
- Department of Pediatrics, Washington University School of Medicine, Saint Louis, Missouri 63110-1093, USA
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150
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Kabuki T, Uenishi H, Seto Y, Yoshioka T, Nakajima H. A unique lantibiotic, thermophilin 1277, containing a disulfide bridge and two thioether bridges. J Appl Microbiol 2009; 106:853-62. [PMID: 19191960 DOI: 10.1111/j.1365-2672.2008.04059.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
AIMS To identify the chemical structure of a bacteriocin, thermophilin 1277, produced by Streptococcus thermophilus SBT1277. METHODS AND RESULTS Thermophilin 1277 was purified and partial N-terminal sequence analysis revealed 6 unidentified amino acids amongst 31 amino acids residues. A 2.7-kbp region containing the thermophilin 1277 structural gene (tepA) encoding 58 amino acids was cloned and sequenced. Mature thermophilin 1277 (33 amino acids) was preceded by a 25-amino acid putative leader peptide containing a double glycine cleavage motif. Peptide sequence analysis following chemical modification of thermophilin 1277 revealed that the Cys21 and Cys29 residues form a disulfide bridge and that Thr8 or Thr10 forms two 3-methyllanthionines with Cys13 or Cys32 via thioether bridges. Antimicrobial activity was disrupted by ethanethiol or reductive agent treatments, indicating that the internal amino acid modifications are crucial for the activity. CONCLUSIONS Thermophilin 1277 from Strep. thermophilus SBT1277 belongs to the class of AII-type lantibiotics that has a disulfide and two thioether bridges. SIGNIFICANCE AND IMPACT OF THE STUDY This is the first report of a lantibiotic produced by a GRAS species of Strep. thermophilus; thermophilin 1277 has a unique structure containing both a disulfide bridge and two thioether bridges that are crucial for its activity.
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Affiliation(s)
- T Kabuki
- Technology and Research Institute, Snow Brand Milk Products, Co. Ltd, Minamidai 1-1-2, Kawagoe, Japan.
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