1
|
Bechtel TD, Hershelman J, Ghoshal M, McLandsborough L, Gibbons JG. Chemical mutagenesis of Listeria monocytogenes for increased tolerance to benzalkonium chloride shows independent genetic underpinnings and off-target antibiotic resistance. PLoS One 2024; 19:e0305663. [PMID: 39028728 PMCID: PMC11259264 DOI: 10.1371/journal.pone.0305663] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Accepted: 06/02/2024] [Indexed: 07/21/2024] Open
Abstract
Listeria monocytogenes, a potentially fatal foodborne pathogen commonly found in food processing facilities, creates a significant economic burden that totals more than $2 billion annually in the United States due to outbreaks. Quaternary ammonium compounds (QACs), including benzalkonium chloride (BAC), are among the most widely used sanitizers to inhibit the growth and spread of L. monocytogenes from food processing facilities. However, resistance to QACs has been increasing in L. monocytogenes and different genetic mechanisms conferring resistance have been discovered. Here, we used ethyl methanesulfonate (EMS) to chemically mutagenize the BAC-susceptible strain, L. monocytogenes FSL-N1-304. We isolated two mutants with increased tolerance to BAC compared to the parental strain. Next, we assessed the off-target effect of increased tolerance to BAC by measuring the minimum inhibitory concentrations (MICs) of a diverse set of antibiotics, revealing that mut-1 and mut-2 displayed significantly increased resistance to fluoroquinolone antibiotics compared to the parental strain. A hemolysis assay was then used to investigate a potential correlation between BAC tolerance and virulence. Interestingly, mut-1 and mut-2 both exhibited significantly higher hemolysis percentage than the parental strain. We then sequenced the genomes of the parental strain and both mutants to identify mutations that may be involved in the increased resistance to BAC. We identified 3 and 29 mutations in mut-1 and mut-2, respectively. mut-1 contained nonsynonymous mutations in dagK (a diacylglycerol kinase), lmo2768 (a permease-encoding gene), and lmo0186 (resuscitation promoting factor). mut-2 contained a nonsense mutation in the nucleotide excision repair enzyme UvrABC system protein B encoding gene, uvrB, which likely accounts for the higher number of mutations observed. Transcriptome analysis in the presence of BAC revealed that genes related to the phosphotransferase system and internalins were up-regulated in both mutants, suggesting their significance in the BAC stress response. These two mutants provide insights into alternative mechanisms for increased BAC tolerance and could further our understanding of how L. monocytogenes persists in the food processing environment.
Collapse
Affiliation(s)
- Tyler D. Bechtel
- Department of Food Science, University of Massachusetts, Amherst, MA, United States of America
| | - Julia Hershelman
- Department of Food Science, University of Massachusetts, Amherst, MA, United States of America
- Department of Microbiology, University of Massachusetts, Amherst, MA, United States of America
| | - Mrinalini Ghoshal
- Department of Food Science, University of Massachusetts, Amherst, MA, United States of America
- Department of Microbiology, University of Massachusetts, Amherst, MA, United States of America
| | - Lynne McLandsborough
- Department of Microbiology, University of Massachusetts, Amherst, MA, United States of America
| | - John G. Gibbons
- Department of Food Science, University of Massachusetts, Amherst, MA, United States of America
- Molecular and Cellular Biology Graduate Program, University of Massachusetts, Amherst, MA, United States of America
- Organismic & Evolutionary Biology Graduate Program, University of Massachusetts, Amherst, MA, United States of America
| |
Collapse
|
2
|
Wu J, McAuliffe O, O'Byrne CP. Trehalose transport occurs via TreB in Listeria monocytogenes and it influences biofilm development and acid resistance. Int J Food Microbiol 2023; 394:110165. [PMID: 36933360 DOI: 10.1016/j.ijfoodmicro.2023.110165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2022] [Revised: 02/09/2023] [Accepted: 02/28/2023] [Indexed: 03/12/2023]
Abstract
Listeria monocytogenes is a pathogenic bacterium that can inhabit a diverse range of environmental niches. This is largely attributed to the high proportion of carbohydrate-specific phosphotransferase system (PTS) genes in its genome. Carbohydrates can be assimilated as sources of energy but additionally they can serve as niche-specific cues for L. monocytogenes to shape its global gene expression, in order to cope with anticipated stresses. To examine carbon source utilization among wild L. monocytogenes isolates and to understand underlying molecular mechanisms, a diverse collection of L. monocytogenes strains (n = 168) with whole genome sequence (WGS) data available was screened for the ability to grow in chemically defined media with different carbon sources. The majority of the strains grew in glucose, mannose, fructose, cellobiose, glycerol, trehalose, and sucrose. Maltose, lactose, and rhamnose supported slower growth while ribose did not support any growth. In contrast to other strains, strain1386, which belonged to clonal complex 5 (CC5), was unable to grow on trehalose as a sole carbon source. WGS data revealed that it carried a substitution (N352K) in a putative PTS EIIBC trehalose transporter, TreB, while this asparagine residue is conserved in other strains in this collection. Spontaneous mutants of strain 1386 that could grow in trehalose were found to harbour a reversion of the substitution in TreB. These results provide genetic evidence that TreB is responsible for trehalose uptake and that the N352 residue is essential for TreB activity. Moreover, reversion mutants also restored other unusual phenotypes that strain 1386 displayed, i.e. altered colony morphology, impaired biofilm development, and reduced acid resistance. Transcriptional analysis at stationary phase with buffered BHI media revealed that trehalose metabolism positively influences the transcription of genes encoding amino acid-based acid resistance mechanisms. In summary, our results demonstrated that N352 is key to the function of the sole trehalose transporter TreB in L. monocytogenes and suggest that trehalose metabolism alters physiology to favour biofilm development and acid stress resistance. Moreover, since strain 1386 is among the strains recommended by the European Union Reference Laboratory for conducting food challenge studies in order to determine whether or not L. monocytogenes can grow in food, these findings have important implications for food safety.
Collapse
Affiliation(s)
- Jialun Wu
- Bacterial Stress Response Group, Microbiology, School of Biological & Chemical Sciences, University of Galway, Galway H91 TK33, Ireland
| | | | - Conor P O'Byrne
- Bacterial Stress Response Group, Microbiology, School of Biological & Chemical Sciences, University of Galway, Galway H91 TK33, Ireland.
| |
Collapse
|
3
|
Assoni L, Milani B, Carvalho MR, Nepomuceno LN, Waz NT, Guerra MES, Converso TR, Darrieux M. Resistance Mechanisms to Antimicrobial Peptides in Gram-Positive Bacteria. Front Microbiol 2020; 11:593215. [PMID: 33193264 PMCID: PMC7609970 DOI: 10.3389/fmicb.2020.593215] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Accepted: 09/03/2020] [Indexed: 02/06/2023] Open
Abstract
With the alarming increase of infections caused by pathogenic multidrug-resistant bacteria over the last decades, antimicrobial peptides (AMPs) have been investigated as a potential treatment for those infections, directly through their lytic effect or indirectly, due to their ability to modulate the immune system. There are still concerns regarding the use of such molecules in the treatment of infections, such as cell toxicity and host factors that lead to peptide inhibition. To overcome these limitations, different approaches like peptide modification to reduce toxicity and peptide combinations to improve therapeutic efficacy are being tested. Human defense peptides consist of an important part of the innate immune system, against a myriad of potential aggressors, which have in turn developed different ways to overcome the AMPs microbicidal activities. Since the antimicrobial activity of AMPs vary between Gram-positive and Gram-negative species, so do the bacterial resistance arsenal. This review discusses the mechanisms exploited by Gram-positive bacteria to circumvent killing by antimicrobial peptides. Specifically, the most clinically relevant genera, Streptococcus spp., Staphylococcus spp., Enterococcus spp. and Gram-positive bacilli, have been explored.
Collapse
Affiliation(s)
- Lucas Assoni
- Laboratório de Biologia Molecular de Microrganismos, Universidade São Francisco, Bragança Paulista, Brazil
| | - Barbara Milani
- Laboratório de Biologia Molecular de Microrganismos, Universidade São Francisco, Bragança Paulista, Brazil
| | - Marianna Ribeiro Carvalho
- Laboratório de Biologia Molecular de Microrganismos, Universidade São Francisco, Bragança Paulista, Brazil
| | - Lucas Natanael Nepomuceno
- Laboratório de Biologia Molecular de Microrganismos, Universidade São Francisco, Bragança Paulista, Brazil
| | - Natalha Tedeschi Waz
- Laboratório de Biologia Molecular de Microrganismos, Universidade São Francisco, Bragança Paulista, Brazil
| | - Maria Eduarda Souza Guerra
- Laboratório de Biologia Molecular de Microrganismos, Universidade São Francisco, Bragança Paulista, Brazil
| | - Thiago Rojas Converso
- Laboratório de Biologia Molecular de Microrganismos, Universidade São Francisco, Bragança Paulista, Brazil
| | - Michelle Darrieux
- Laboratório de Biologia Molecular de Microrganismos, Universidade São Francisco, Bragança Paulista, Brazil
| |
Collapse
|
4
|
Contributions of a LysR Transcriptional Regulator to Listeria monocytogenes Virulence and Identification of Its Regulons. J Bacteriol 2020; 202:JB.00087-20. [PMID: 32179628 DOI: 10.1128/jb.00087-20] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Accepted: 02/20/2020] [Indexed: 12/22/2022] Open
Abstract
The capacity of Listeria monocytogenes to adapt to environmental changes is facilitated by a large number of regulatory proteins encoded by its genome. Among these proteins are the uncharacterized LysR-type transcriptional regulators (LTTRs). LTTRs can work as positive and/or negative transcription regulators at both local and global genetic levels. Previously, our group determined by comparative genome analysis that one member of the LTTRs (NCBI accession no. WP_003734782) was present in pathogenic strains but absent from nonpathogenic strains. The goal of the present study was to assess the importance of this transcription factor in the virulence of L. monocytogenes strain F2365 and to identify its regulons. An L. monocytogenes strain lacking lysR (the F2365ΔlysR strain) displayed significant reductions in cell invasion of and adhesion to Caco-2 cells. In plaque assays, the deletion of lysR resulted in a 42.86% decrease in plaque number and a 13.48% decrease in average plaque size. Furthermore, the deletion of lysR also attenuated the virulence of L. monocytogenes in mice following oral and intraperitoneal inoculation. The analysis of transcriptomics revealed that the transcript levels of 139 genes were upregulated, while 113 genes were downregulated in the F2365ΔlysR strain compared to levels in the wild-type bacteria. lysR-repressed genes included ABC transporters, important for starch and sucrose metabolism as well as glycerolipid metabolism, flagellar assembly, quorum sensing, and glycolysis/gluconeogenesis. Conversely, lysR activated the expression of genes related to fructose and mannose metabolism, cationic antimicrobial peptide (CAMP) resistance, and beta-lactam resistance. These data suggested that lysR contributed to L. monocytogenes virulence by broad impact on multiple pathways of gene expression.IMPORTANCE Listeria monocytogenes is the causative agent of listeriosis, an infectious and fatal disease of animals and humans. In this study, we have shown that lysR contributes to Listeria pathogenesis and replication in cell lines. We also highlight the importance of lysR in regulating the transcription of genes involved in different pathways that might be essential for the growth and persistence of L. monocytogenes in the host or under nutrient limitation. Better understanding L. monocytogenes pathogenesis and the role of various virulence factors is necessary for further development of prevention and control strategies.
Collapse
|
5
|
Liu S, Liu Y, Takala TM, Zhang P, Wang S. Phenotypic comparison and DNA sequencing analysis of a wild-type and a pediocin-resistant mutant of Listeria ivanovii. Res Microbiol 2020; 171:115-121. [PMID: 32119904 DOI: 10.1016/j.resmic.2020.02.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Revised: 02/17/2020] [Accepted: 02/21/2020] [Indexed: 11/25/2022]
Abstract
Listeria ivanovii is one of the two pathogenic species within the genus Listeria, the other being Listeria monocytogenes. In this study, we generated a stable pediocin resistant mutant Liv-r1 of a L. ivanovii strain, compared phenotypic differences between the wild-type and the mutant, localised the pediocin-induced mutations in the chromosome, and analysed the mechanisms behind the bacteriocin resistance. In addition to pediocin resistance, Liv-r1 was also less sensitive to nisin. The growth of Liv-r1 was significantly reduced with glucose and mannose, but less with cellobiose. The cells of Liv-r1 adsorbed less pediocin than the wild-type cells. Consequently, with less pediocin on the cell surface, the mutant was also less leaky, as shown as the release of intracellular lactate dehydrogenase to the supernatant. The surface of the mutant cells was more hydrophobic than that of the wild-type. Whole genome sequencing revealed numerous changes in the Liv-r1 chromosome. The mutations were found e.g., in genes encoding sigma-54-dependent transcription regulator and internalin B, as well as in genes involved in metabolism of carbohydrates such as glucose and cellobiose. Genetic differences observed in the mutant may be responsible for resistance to pediocin but no direct evidence is provided.
Collapse
Affiliation(s)
- Shanna Liu
- College of Food Science and Bioengineering, Tianjin Agricultural University, Tianjin, 300392, People's Republic of China.
| | - Yongjun Liu
- College of Food Science and Bioengineering, Tianjin Agricultural University, Tianjin, 300392, People's Republic of China.
| | - Timo M Takala
- Department of Microbiology, University of Helsinki, Finland.
| | - Pingping Zhang
- College of Food Science and Bioengineering, Tianjin Agricultural University, Tianjin, 300392, People's Republic of China.
| | - Suhua Wang
- College of Food Science and Bioengineering, Tianjin Agricultural University, Tianjin, 300392, People's Republic of China.
| |
Collapse
|
6
|
Masias E, Dupuy FG, da Silva Sanches PR, Farizano JV, Cilli E, Bellomio A, Saavedra L, Minahk C. Impairment of the class IIa bacteriocin receptor function and membrane structural changes are associated to enterocin CRL35 high resistance in Listeria monocytogenes. Biochim Biophys Acta Gen Subj 2017; 1861:1770-1776. [DOI: 10.1016/j.bbagen.2017.03.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Revised: 03/14/2017] [Accepted: 03/16/2017] [Indexed: 10/19/2022]
|
7
|
Characterization of Class IIa Bacteriocin Resistance in Enterococcus faecium. Antimicrob Agents Chemother 2017; 61:AAC.02033-16. [PMID: 28115354 DOI: 10.1128/aac.02033-16] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Accepted: 01/16/2017] [Indexed: 12/16/2022] Open
Abstract
Vancomycin-resistant enterococci, particularly resistant Enterococcus faecium, pose an escalating threat in nosocomial environments because of their innate resistance to many antibiotics, including vancomycin, a treatment of last resort. Many class IIa bacteriocins strongly target these enterococci and may offer a potential alternative for the management of this pathogen. However, E. faecium's resistance to these peptides remains relatively uncharacterized. Here, we explored the development of resistance of E. faecium to a cocktail of three class IIa bacteriocins: enterocin A, enterocin P, and hiracin JM79. We started by quantifying the frequency of resistance to these peptides in four clinical isolates of E. faecium We then investigated the levels of resistance of E. faecium 6E6 mutants as well as their fitness in different carbon sources. In order to elucidate the mechanism of resistance of E. faecium to class IIa bacteriocins, we completed whole-genome sequencing of resistant mutants and performed reverse transcription-quantitative PCR (qRT-PCR) of a suspected target mannose phosphotransferase (ManPTS). We then verified this ManPTS's role in bacteriocin susceptibility by showing that expression of the ManPTS in Lactococcus lactis results in susceptibility to the peptide cocktail. Based on the evidence found from these studies, we conclude that, in accord with other studies in E. faecalis and Listeria monocytogenes, resistance to class IIa bacteriocins in E. faecium 6E6 is likely caused by the disruption of a particular ManPTS, which we believe we have identified.
Collapse
|
8
|
Interaction with enzyme IIBMpo (EIIBMpo) and phosphorylation by phosphorylated EIIBMpo exert antagonistic effects on the transcriptional activator ManR of Listeria monocytogenes. J Bacteriol 2015; 197:1559-72. [PMID: 25691525 DOI: 10.1128/jb.02522-14] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Accepted: 02/06/2015] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Listeriae take up glucose and mannose predominantly through a mannose class phosphoenolpyruvate:carbohydrate phosphotransferase system (PTS(Man)), whose three components are encoded by the manLMN genes. The expression of these genes is controlled by ManR, a LevR-type transcription activator containing two PTS regulation domains (PRDs) and two PTS-like domains (enzyme IIA(Man) [EIIA(Man)]- and EIIB(Gat)-like). We demonstrate here that in Listeria monocytogenes, ManR is activated via the phosphorylation of His585 in the EIIA(Man)-like domain by the general PTS components enzyme I and HPr. We also show that ManR is regulated by the PTS(Mpo) and that EIIB(Mpo) plays a dual role in ManR regulation. First, yeast two-hybrid experiments revealed that unphosphorylated EIIB(Mpo) interacts with the two C-terminal domains of ManR (EIIB(Gat)-like and PRD2) and that this interaction is required for ManR activity. Second, in the absence of glucose/mannose, phosphorylated EIIB(Mpo) (P∼EIIB(Mpo)) inhibits ManR activity by phosphorylating His871 in PRD2. The presence of glucose/mannose causes the dephosphorylation of P∼EIIB(Mpo) and P∼PRD2 of ManR, which together lead to the induction of the manLMN operon. Complementation of a ΔmanR mutant with various manR alleles confirmed the antagonistic effects of PTS-catalyzed phosphorylation at the two different histidine residues of ManR. Deletion of manR prevented not only the expression of the manLMN operon but also glucose-mediated repression of virulence gene expression; however, repression by other carbohydrates was unaffected. Interestingly, the expression of manLMN in Listeria innocua was reported to require not only ManR but also the Crp-like transcription activator Lin0142. Unlike Lin0142, the L. monocytogenes homologue, Lmo0095, is not required for manLMN expression; its absence rather stimulates man expression. IMPORTANCE Listeria monocytogenes is a human pathogen causing the foodborne disease listeriosis. The expression of most virulence genes is controlled by the transcription activator PrfA. Its activity is strongly repressed by carbohydrates, including glucose, which is transported into L. monocytogenes mainly via a mannose/glucose-specific phosphotransferase system (PTS(Man)). Expression of the man operon is regulated by the transcription activator ManR, the activity of which is controlled by a second, low-efficiency PTS of the mannose family, which functions as glucose sensor. Here we demonstrate that the EIIB(Mpo) component plays a dual role in ManR regulation: it inactivates ManR by phosphorylating its His871 residue and stimulates ManR by interacting with its two C-terminal domains.
Collapse
|
9
|
Electrophoretic pattern and antibacterial activity of proteins from vicia faba seed extract. INTERNATIONAL JOURNAL OF MOLECULAR AND CELLULAR MEDICINE 2013; 2:46-9. [PMID: 24551790 PMCID: PMC3920516] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/11/2013] [Accepted: 03/03/2013] [Indexed: 11/06/2022]
Abstract
Antibiotic resistance makes Antimierobial peptides (AMPs) agents an alternative for treatment of pathogenic diseases. They are isolated from various invertebrate animals, vertebrates and plants. The present study shows the electrophoretic pattern of protein and peptides from Vicia faba seed and reports our first attempt to study the antibacterial activity of Vicia faba seed extract. The crude extract electrophoresis was carried out on 12% SDS- PAGE gel. Antibacterial activity on E. Coli and B. Subtilis from hospital infection was tested and evaluated by measuring the inhibition zone diameter observation. The SDS- PAGE gel electrophoresis shows that the crude extract contains many proteins and peptides with different molecular weight. The inhibition zone was not observed in antibacterial properties tests. Thus, our experiments don't show any antibacterial activity on E. Coli and B. Subtilis from hospital isolates. Some other AMPs haven't also shown any antimicrobial properties on clinical trial. The antibacterial activity of the crude Vicia faba seed extract should also be tested on standard bacteria.
Collapse
|
10
|
Cui Y, Zhang C, Wang Y, Shi J, Zhang L, Ding Z, Qu X, Cui H. Class IIa bacteriocins: diversity and new developments. Int J Mol Sci 2012; 13:16668-707. [PMID: 23222636 PMCID: PMC3546714 DOI: 10.3390/ijms131216668] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2012] [Revised: 10/10/2012] [Accepted: 11/12/2012] [Indexed: 12/02/2022] Open
Abstract
Class IIa bacteriocins are heat-stable, unmodified peptides with a conserved amino acids sequence YGNGV on their N-terminal domains, and have received much attention due to their generally recognized as safe (GRAS) status, their high biological activity, and their excellent heat stability. They are promising and attractive agents that could function as biopreservatives in the food industry. This review summarizes the new developments in the area of class IIa bacteriocins and aims to provide uptodate information that can be used in designing future research.
Collapse
Affiliation(s)
- Yanhua Cui
- School of Food Science and Engineering, Harbin Institute of Technology, Harbin 150090, China; E-Mails: (Y.C.); (C.Z.); (Z.D.)
| | - Chao Zhang
- School of Food Science and Engineering, Harbin Institute of Technology, Harbin 150090, China; E-Mails: (Y.C.); (C.Z.); (Z.D.)
| | - Yunfeng Wang
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150001, China; E-Mail:
| | - John Shi
- Guelph Food Research Center, Agriculture and Agri-Food Canada, Guelph, ON N1G5C9, Canada; E-Mail:
| | - Lanwei Zhang
- School of Food Science and Engineering, Harbin Institute of Technology, Harbin 150090, China; E-Mails: (Y.C.); (C.Z.); (Z.D.)
| | - Zhongqing Ding
- School of Food Science and Engineering, Harbin Institute of Technology, Harbin 150090, China; E-Mails: (Y.C.); (C.Z.); (Z.D.)
| | - Xiaojun Qu
- Institute of Microbiology, Heilongjiang Academy of Sciences, Harbin 150010, China; E-Mail:
| | - Hongyu Cui
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150001, China; E-Mail:
| |
Collapse
|
11
|
Aké FMD, Joyet P, Deutscher J, Milohanic E. Mutational analysis of glucose transport regulation and glucose-mediated virulence gene repression in Listeria monocytogenes. Mol Microbiol 2011; 81:274-93. [PMID: 21564334 DOI: 10.1111/j.1365-2958.2011.07692.x] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Listeria monocytogenes transports glucose/mannose via non-PTS permeases and phosphoenolpyruvate:carbohydrate phosphotransferase systems (PTS). Two mannose class PTS are encoded by the constitutively expressed mpoABCD and the inducible manLMN operons. The man operon encodes the main glucose transporter because manL or manM deletion significantly slows glucose utilization, whereas mpoA deletion has no effect. The PTS(Mpo) mainly functions as a constitutively synthesized glucose sensor controlling man operon expression by phosphorylating and interacting with ManR, a LevR-like transcription activator. EIIB(Mpo) plays a dual role in ManR regulation: P~EIIB(Mpo) prevailing in the absence of glucose phosphorylates and thereby inhibits ManR activity, whereas unphosphorylated EIIB(Mpo) prevailing during glucose uptake is needed to render ManR active. In contrast to mpoA, deletion of mpoB therefore strongly inhibits man operon expression and glucose consumption. A ΔptsI (EI) mutant consumes glucose at an even slower rate probably via GlcU-like non-PTS transporters. Interestingly, deletion of ptsI, manL, manM or mpoB causes elevated PrfA-mediated virulence gene expression. The PTS(Man) is the major player in glucose-mediated PrfA inhibition because the ΔmpoA mutant showed normal PrfA activity. The four mutants showing PrfA derepression contain no or only little unphosphorylated EIIAB(Man) (ManL), which probably plays a central role in glucose-mediated PrfA regulation.
Collapse
Affiliation(s)
- Francine M D Aké
- Laboratoire de Microbiologie de l'Alimentation au Service de la Santé, AgroParisTech-INRA UMR1319, 78850 Thiverval-Grignon, France
| | | | | | | |
Collapse
|
12
|
Mechanisms of resistance to bacteriocins targeting the mannose phosphotransferase system. Appl Environ Microbiol 2011; 77:3335-42. [PMID: 21421780 DOI: 10.1128/aem.02602-10] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The membrane proteins IIC and IID of the mannose phosphotransferase system (Man-PTS) together form a membrane-located complex that serves as a receptor for several different bacteriocins, including the pediocin-like class IIa bacteriocins and the class IIc bacteriocin lactococcin A. Bacterial strains sensitive to class IIa bacteriocins readily give rise to resistant mutants upon bacteriocin exposure. In the present study, we have therefore investigated lactococcin A-resistant mutants of Lactococcus lactis as well as natural food isolates of Listeria monocytogenes with different susceptibilities to class IIa bacteriocins. We found two major mechanisms of resistance. The first involves downregulation of Man-PTS gene expression, which takes place both in spontaneous resistant mutants and in natural resistant isolates. The second involves normal expression of the Man-PTS system, but the underlying mechanism of resistance for these cells is unknown. In some cases, the resistant phenotype was linked to a shift in the metabolism; i.e., reduced growth on glucose due to reduction in Man-PTS expression was accompanied by enhanced growth on another sugar, such as galactose. The implications of these findings in terms of metabolic heterogeneity are discussed.
Collapse
|
13
|
Enhancing isoprene production by genetic modification of the 1-deoxy-d-xylulose-5-phosphate pathway in Bacillus subtilis. Appl Environ Microbiol 2011; 77:2399-405. [PMID: 21296950 DOI: 10.1128/aem.02341-10] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
To enhance the production of isoprene, a volatile 5-carbon hydrocarbon, in the Gram-positive spore-forming rod-shaped bacterium Bacillus subtilis, 1-deoxy-d-xylulose-5-phosphate synthase (Dxs) and 1-deoxy-d-xylulose-5-phosphate reductoisomerase (Dxr) were overexpressed in B. subtilis DSM 10. For the strain that overexpresses Dxs, the yield of isoprene was increased 40% over that by the wild-type strain. In the Dxr overexpression strain, the level of isoprene production was unchanged. Overexpression of Dxr together with Dxs showed an isoprene production level similar to that of the Dxs overproduction strain. The effects of external factors, such as stress factors including heat (48°C), salt (0.3 M NaCl), ethanol (1%), and oxidative (0.005% H(2)O(2)) stress, on isoprene production were further examined. Heat, salt, and H(2)O(2) induced isoprene production; ethanol inhibited isoprene production. In addition, induction and repression effects are independent of SigB, which is the general stress-responsive alternative sigma factor of Gram-positive bacteria.
Collapse
|
14
|
Regulation of mannose phosphotransferase system permease and virulence gene expression in Listeria monocytogenes by the EII(t)Man transporter. Appl Environ Microbiol 2009; 75:6671-8. [PMID: 19734332 DOI: 10.1128/aem.01104-09] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The EII(t)(Man) phosphotransferase system (PTS) permease encoded by the mpt operon is the principal glucose transporter in Listeria monocytogenes. EII(t)(Man) participates in glucose-mediated carbon catabolite repression (CCR) and downregulation of virulence gene expression, and it is the receptor for class IIa bacteriocins. The regulation of this important protein and its roles in gene control were examined using derivatives of strain EGD-e in which the mpt operon or its regulatory genes, manR and lmo0095, were deleted. Real-time reverse transcription-PCR analysis showed that the mpt mRNA level was 10- and 100-fold lower in the lmo0095 and manR deletion strains, respectively. The manR mRNA level was higher in the mpt deletion mutant in medium lacking glucose, possibly due to disruption of a regulatory process that normally downregulates manR transcription in the absence of this sugar. Analysis of the mpt deletion mutant also showed that EII(t)(Man) participates to various degrees in glucose-mediated CCR of PTS operons. CCR of the lmo0027 gene, which encodes a beta-glucoside PTS transporter, required expression of EII(t)(Man). In contrast, genes in two mannose PTS operons (lmo0024, lmo1997, and lmo2002) were repressed by glucose even when EII(t)(Man) was not synthesized. A third mannose PTS operon, mpo, was not regulated by glucose or by the level of EII(t)(Man). Finally, the mRNA levels for five genes in the prfA virulence gene cluster were two- to fourfold higher in the mpt deletion mutant. The results show that EII(t)(Man) participates to various extents in glucose-mediated CCR of PTS operons and makes a small, albeit significant, contribution to downregulation of virulence gene transcription by glucose in strain EGD-e.
Collapse
|
15
|
Exogenous or L-rhamnose-derived 1,2-propanediol is metabolized via a pduD-dependent pathway in Listeria innocua. Appl Environ Microbiol 2008; 74:7073-9. [PMID: 18805996 DOI: 10.1128/aem.01074-08] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
1,2-Propanediol (1,2-PD) added exogenously to cultures or produced endogenously from l-rhamnose is metabolized to n-propanol and propionate in Listeria innocua Lin11. The pduD gene, which encodes a diol dehydratase ss subunit homolog, is required for 1,2-PD catabolism. pduD and 16 other genes within the pduA-to-pduF region of a large gene cluster are induced in medium containing 1,2-PD.
Collapse
|
16
|
Xue J, Miller KW. Regulation of the mpt operon in Listeria innocua by the ManR protein. Appl Environ Microbiol 2007; 73:5648-52. [PMID: 17616620 PMCID: PMC2042094 DOI: 10.1128/aem.00052-07] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The phosphotransferase system regulation domain (PRD)-containing activator, ManR, is required for glucose-controlled transcription of the mannose permease two (mpt) operon in Listeria innocua. His-871 in ManR PRD-II is needed for mpt repression in glucose-free media. His-506 in PRD-I is needed for mpt induction by glucose.
Collapse
Affiliation(s)
- Junfeng Xue
- Department of Molecular Biology, University of Wyoming, 1000 E. University Avenue, Dept. 3944, Laramie, WY 82071-3944, USA
| | | |
Collapse
|
17
|
Deutscher J, Francke C, Postma PW. How phosphotransferase system-related protein phosphorylation regulates carbohydrate metabolism in bacteria. Microbiol Mol Biol Rev 2007; 70:939-1031. [PMID: 17158705 PMCID: PMC1698508 DOI: 10.1128/mmbr.00024-06] [Citation(s) in RCA: 989] [Impact Index Per Article: 58.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
The phosphoenolpyruvate(PEP):carbohydrate phosphotransferase system (PTS) is found only in bacteria, where it catalyzes the transport and phosphorylation of numerous monosaccharides, disaccharides, amino sugars, polyols, and other sugar derivatives. To carry out its catalytic function in sugar transport and phosphorylation, the PTS uses PEP as an energy source and phosphoryl donor. The phosphoryl group of PEP is usually transferred via four distinct proteins (domains) to the transported sugar bound to the respective membrane component(s) (EIIC and EIID) of the PTS. The organization of the PTS as a four-step phosphoryl transfer system, in which all P derivatives exhibit similar energy (phosphorylation occurs at histidyl or cysteyl residues), is surprising, as a single protein (or domain) coupling energy transfer and sugar phosphorylation would be sufficient for PTS function. A possible explanation for the complexity of the PTS was provided by the discovery that the PTS also carries out numerous regulatory functions. Depending on their phosphorylation state, the four proteins (domains) forming the PTS phosphorylation cascade (EI, HPr, EIIA, and EIIB) can phosphorylate or interact with numerous non-PTS proteins and thereby regulate their activity. In addition, in certain bacteria, one of the PTS components (HPr) is phosphorylated by ATP at a seryl residue, which increases the complexity of PTS-mediated regulation. In this review, we try to summarize the known protein phosphorylation-related regulatory functions of the PTS. As we shall see, the PTS regulation network not only controls carbohydrate uptake and metabolism but also interferes with the utilization of nitrogen and phosphorus and the virulence of certain pathogens.
Collapse
Affiliation(s)
- Josef Deutscher
- Microbiologie et Génétique Moléculaire, INRA-CNRS-INA PG UMR 2585, Thiverval-Grignon, France.
| | | | | |
Collapse
|
18
|
Erni B. The mannose transporter complex: an open door for the macromolecular invasion of bacteria. J Bacteriol 2006; 188:7036-8. [PMID: 17015642 PMCID: PMC1636239 DOI: 10.1128/jb.01074-06] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- Bernhard Erni
- Department of Chemistry and Biochemistry, University of Bern, Freiestr. 3, CH-3012 Bern, Switzerland.
| |
Collapse
|
19
|
Fimland G, Pirneskoski J, Kaewsrichan J, Jutila A, Kristiansen PE, Kinnunen PKJ, Nissen-Meyer J. Mutational analysis and membrane-interactions of the β-sheet-like N-terminal domain of the pediocin-like antimicrobial peptide sakacin P. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2006; 1764:1132-40. [PMID: 16762606 DOI: 10.1016/j.bbapap.2006.04.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2006] [Revised: 04/03/2006] [Accepted: 04/03/2006] [Indexed: 11/16/2022]
Abstract
To gain insight into how the N-terminal three-stranded beta-sheet-like domain in pediocin-like antimicrobial peptides positions itself on membranes, residues in the well-conserved (Y)YGNGV-motif in the domain were substituted and the effect of the substitutions on antimicrobial activity and binding of peptides to liposomes was determined. Peptide-liposome interactions were detected by measuring tryptophan-fluorescence upon exposing liposomes to peptides in which a tryptophan residue had been introduced in the N-terminal domain. The results revealed that the N-terminal domain associates readily with anionic liposomes, but not with neutral liposomes. The electrostatic interactions between peptides and liposomes facilitated the penetration of some of the peptide residues into the liposomes. Measuring the antimicrobial activity of the mutated peptides revealed that the Tyr2Leu and Tyr3Leu mutations resulted in about a 10-fold reduction in activity, whereas the Tyr2Trp, Tyr2Phe, Tyr3Trp and Tyr3Phe mutations were tolerated fairly well, especially the mutations in position 3. The Val7Ile mutation did not have a marked detrimental effect on the activity. The Gly6Ala mutation was highly detrimental, consistent with Gly6 being in one of the turns in the beta-sheet-like N-terminal domain, whereas the Gly4Ala mutation was tolerated fairly well. All mutations involving Asn5, including the conservative mutations Asn5Gln and Asn5Asp, were very deleterious. Thus, both the polar amide group on the side chain of Asn5 and its exact position in space were crucial for the peptides to be fully active. Taken together, the results are consistent with Val7 positioning itself in the hydrophobic core of target membranes, thus forcing most of the other residues in the N-terminal domain into the membrane interface region: Tyr3 and Asn5 in the lower half with their side chains pointing downward and approaching the hydrophobic core, Tyr2, Gly4 and His8 and 12 in the upper half, Lys1 near the middle of the interface region, and the side chain of Lys11 pointing out toward the membrane surface.
Collapse
Affiliation(s)
- Gunnar Fimland
- Department of Molecular Biosciences, University of Oslo, Post box 1041, Blindern, 0316 Oslo, Norway.
| | | | | | | | | | | | | |
Collapse
|
20
|
Abstract
Bacteriocins are bacterially produced antimicrobial peptides with narrow or broad host ranges. Many bacteriocins are produced by food-grade lactic acid bacteria, a phenomenon which offers food scientists the possibility of directing or preventing the development of specific bacterial species in food. This can be particularly useful in preservation or food safety applications, but also has implications for the development of desirable flora in fermented food. In this sense, bacteriocins can be used to confer a rudimentary form of innate immunity to foodstuffs, helping processors extend their control over the food flora long after manufacture.
Collapse
Affiliation(s)
- Paul D Cotter
- Alimentary Pharmabiotic Centre, Microbiology Department, University College Cork, Cork, Ireland
| | | | | |
Collapse
|