1
|
Wang XY, Yan J, Xie J. Coculture of Acinetobacter johnsonii and Shewanella putrefaciens Contributes to the ABC Transporter that Impacts Cold Adaption in the Aquatic Food Storage Environment. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2024; 72:10605-10615. [PMID: 38647030 DOI: 10.1021/acs.jafc.4c00885] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/25/2024]
Abstract
Acinetobacter johnsonii and Shewanella putrefaciens were identified as specific spoilage organisms in aquatic food. The interactions among specific spoilage organisms under cold stress have a significant impact on the assembly of microbial communities, which play crucial roles in the spoilage and cold adaptation processes. The limited understanding of A. johnsonii and S. putrefaciens interactions in the cold adaptation mechanism hinders the elucidation of their roles in protein and metabolism levels. 4D quantitative proteomic analysis showed that the coculture of A. johnsonii and S. putrefaciens responds to low temperatures through ABC transporter proteins, resulting in phospholipid transport and inner membrane components. SapA and FtsX proteins were significantly upregulated, while LolC, LolD, LolE, PotD, PotA, PotB, and PotC proteins were significantly downregulated. Metabolome assays revealed that metabolites of glutathione and spermidine/putrescin were significantly upregulated, while metabolites of arginine/lysine/ornithine were significantly downregulated and involved in the ABC transporter metabolism. The results of ultramicroscopic analyses showed that the coculture of A. johnsonii and S. putrefaciens surface combined with the presence of the leakage of intracellular contents, suggesting that the bacteria were severely damaged and wrinkled to absorb metabolic nutrients and adapt to cold temperatures.
Collapse
Affiliation(s)
- Xin-Yun Wang
- International Peace Maternity & Child Health Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200300, China
- College of Food Science & Technology, Shanghai Ocean University, Shanghai 201306, China
- Shanghai Engineering Research Center of Aquatic Product Processing & Preservation, Shanghai Ocean University, Shanghai 201306, China
- Shanghai Professional Technology Service Platform on Cold Chain Equipment Performance and Energy Saving Evaluation, Shanghai Ocean University, Shanghai 201306, China
| | - Jun Yan
- College of Food Science & Technology, Shanghai Ocean University, Shanghai 201306, China
- Shanghai Engineering Research Center of Aquatic Product Processing & Preservation, Shanghai Ocean University, Shanghai 201306, China
- Shanghai Professional Technology Service Platform on Cold Chain Equipment Performance and Energy Saving Evaluation, Shanghai Ocean University, Shanghai 201306, China
- National Experimental Teaching Demonstration Center for Food Science and Engineering Shanghai Ocean University, Shanghai 201306, China
| | - Jing Xie
- College of Food Science & Technology, Shanghai Ocean University, Shanghai 201306, China
- Shanghai Engineering Research Center of Aquatic Product Processing & Preservation, Shanghai Ocean University, Shanghai 201306, China
- Shanghai Professional Technology Service Platform on Cold Chain Equipment Performance and Energy Saving Evaluation, Shanghai Ocean University, Shanghai 201306, China
- National Experimental Teaching Demonstration Center for Food Science and Engineering Shanghai Ocean University, Shanghai 201306, China
| |
Collapse
|
2
|
Biswas S. Synthesis of a Novel Lantibiotic Using Mutacin II Biosynthesis Apparatus. Microbiol Spectr 2023; 11:e0303022. [PMID: 36645288 PMCID: PMC9927145 DOI: 10.1128/spectrum.03030-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Accepted: 12/06/2022] [Indexed: 01/17/2023] Open
Abstract
Owing to extensive metagenomic studies, we now have access to numerous sequences of novel bacteriocin-like antimicrobial peptides encoded by various cultivable and noncultivable bacteria. However, relatively rarely, we even have access to these cultivable strains to examine the potency and the targets of the predicted bacteriocins. In this study, we evaluated a heterologous biosynthetic system to produce biologically active nonnative novel lantibiotics, which are modified bacteriocins. We chose Streptococcus mutans, a dental pathogen, as the host organism because it is genetically easy to manipulate and is inherently a prolific producer of various bacteriocins. We chose the S. mutans T8 strain as the host, which produces the lantibiotic mutacin II, to express 10 selected homologs of mutacin II identified from GenBank. These lantibiotic peptides either are novel or have been studied very minimally. The core regions of the selected lantibiotic peptides were fused to the leader sequence of the mutacin II peptide and integrated into the chromosome such that the core region of the native mutacin II was replaced with the new core sequences. By this approach, using the mutacin II biosynthesis machinery, we obtained one bioactive novel lantibiotic peptide with 52% different residues compared to the mutacin II core region. This unknown lantibiotic is encoded by Streptococcus agalactiae and Streptococcus ovuberis strains. Since this peptide displays some homology with nukacin ISK-1, we named it nukacin Spp. 2. This study demonstrated that the mutacin II biosynthesis machinery can be successfully used as an efficient system for the production of biologically active novel lantibiotics. IMPORTANCE In this study, we report for the first time that Streptococcus mutans can be used as a host to produce various nonnative lantibiotics. We showed that in the T8 strain, we could produce bioactive lacticin 481 and nukacin ISK-1, both of which are homologs of mutacin II, using T8's modification and secretion apparatus. Similarly, we also synthesized a novel bioactive lantibiotic, which we named nukacin Spp. 2.
Collapse
Affiliation(s)
- Saswati Biswas
- Department of Microbiology, Molecular Genetics, and Immunology, University of Kansas Medical Center, Kansas City, Kansas, USA
| |
Collapse
|
3
|
Pandey SD, Biswas I. Clp ATPases differentially affect natural competence development in Streptococcus mutans. Microbiologyopen 2022; 11:e1288. [PMID: 35765180 PMCID: PMC9108599 DOI: 10.1002/mbo3.1288] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Accepted: 04/27/2022] [Indexed: 11/25/2022] Open
Abstract
In naturally competent bacteria, DNA transformation through horizontal gene transfer is an evolutionary mechanism to receive extracellular DNA. Bacteria need to maintain a state of competence to accept foreign DNA, and this is an energy-driven phenomenon that is tightly controlled. In Streptococcus, competence development is a complex process that is not fully understood. In this study, we used Streptococcus mutans, an oral bacterium, to determine how cell density affects competence development. We found that in S. mutans the transformation efficiency is maximum when the transforming DNA was added at low cell density and incubated for 2.5 h before selecting for transformants. We also found that S. mutans cells remain competent until the mid-logarithmic phase, after which the competence decreases drastically. Surprisingly, we observed that individual components of Clp proteolytic complexes differentially regulate competence. If the transformation is carried out at the early growth phase, both ClpP protease and ClpX ATPase are needed for competence. In contrast, we found that both ClpC and ClpE negatively affect competence. We also found that if the transformation is carried out at the mid-logarithmic growth phase ClpX is still required for competence, but ClpP negatively affects competence. While the exact reason for this differential effect of ClpP and ClpX on transformation is currently unknown, we found that both ClpC and ClpE have a negative effect on transformation, which was not reported before.
Collapse
Affiliation(s)
- Satya D. Pandey
- Department of MicrobiologyUniversity of Kansas Medical CenterKansas CityKansasUSA
| | - Indranil Biswas
- Department of MicrobiologyUniversity of Kansas Medical CenterKansas CityKansasUSA
| |
Collapse
|
4
|
Lee K, Kaspar JR, Rojas-Carreño G, Walker AR, Burne RA. A single system detects and protects the beneficial oral bacterium Streptococcus sp. A12 from a spectrum of antimicrobial peptides. Mol Microbiol 2021; 116:211-230. [PMID: 33590560 DOI: 10.1111/mmi.14703] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 02/11/2021] [Accepted: 02/11/2021] [Indexed: 10/22/2022]
Abstract
The commensal bacterium Streptococcus sp. A12 has multiple properties that may promote the stability of health-associated oral biofilms, including overt antagonism of the dental caries pathogen Streptococcus mutans. A LanFEG-type ABC transporter, PcfFEG, confers tolerance to the lantibiotic nisin and enhances the ability of A12 to compete against S. mutans. Here, we investigated the regulation of pcfFEG and adjacent genes for a two-component system, pcfRK, to better understand antimicrobial peptide resistance by A12. Induction of pcfFEG-pcfRK was the primary mechanism to respond rapidly to nisin. In addition to nisin, PcfFEG conferred tolerance by A12 to a spectrum of lantibiotic and non-lantibiotic antimicrobial peptides produced by a diverse collection of S. mutans isolates. Loss of PcfFEG resulted in the altered spatio-temporal arrangement of A12 and S. mutans in a dual-species biofilm model. Deletion of PcfFEG or PcfK resulted in constitutive activation of pcfFEG and expression of pcfFEG was inhibited by small peptides in the pcfK mutant. Transcriptional profiling of pcfR or pcfK mutants combined with functional genomics revealed peculiarities in PcfK function and a novel panel of genes responsive to nisin. Collectively, the results provide fundamental insights that strengthen the foundation for the design of microbial-based therapeutics to control oral infectious diseases.
Collapse
Affiliation(s)
- Kyulim Lee
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, FL, USA
| | - Justin R Kaspar
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, FL, USA.,Division of Biosciences, College of Dentistry, Ohio State University, Columbus, OH, USA
| | - Gisela Rojas-Carreño
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, FL, USA
| | - Alejandro R Walker
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, FL, USA
| | - Robert A Burne
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, FL, USA
| |
Collapse
|
5
|
Complete Genome Sequence of Streptococcus mutans Strain MD, Which Produces Highly Potent Mutacins. Microbiol Resour Announc 2020; 9:9/33/e00616-20. [PMID: 32817148 PMCID: PMC7427186 DOI: 10.1128/mra.00616-20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Here, we report the complete genome sequence of Streptococcus mutans strain MD, which produces potent mutacins capable of inhibiting streptococci. MD is a relatively uncharacterized strain whose genome information was unavailable. This study provides useful information for comparative genomic study and for understanding the repertoire of mutacins in S. mutans. Here, we report the complete genome sequence of Streptococcus mutans strain MD, which produces potent mutacins capable of inhibiting streptococci. MD is a relatively uncharacterized strain whose genome information was unavailable. This study provides useful information for comparative genomic study and for understanding the repertoire of mutacins in S. mutans.
Collapse
|
6
|
Chaudhry V, Patil PB. Evolutionary insights into adaptation of Staphylococcus haemolyticus to human and non-human niches. Genomics 2019; 112:2052-2062. [PMID: 31785311 DOI: 10.1016/j.ygeno.2019.11.018] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2019] [Revised: 11/16/2019] [Accepted: 11/26/2019] [Indexed: 11/16/2022]
Abstract
Staphylococcus haemolyticus is a well-known member of human skin microbiome and an emerging opportunistic human pathogen. Presently, evolutionary studies are limited to human isolates even though it is reported from plants with beneficial properties and in environmental settings. In the present study, we report isolation of novel S. haemolyticus strains from surface sterilized rice seeds and compare their genome to other isolates from diverse niches available in public domain. The study showed expanding nature of pan-genome and revealed set of genes with putative functions related to its adaptability. This is seen by presence of type II lanthipeptide cluster in rice isolates, metal homeostasis genes in an isolate from copper coin and gene encoding methicillin resistance in human isolates. The present study on differential genome dynamics and role of horizontal gene transfers has provided novel insights into capability for ecological diversification of a bacterium of significance to human health.
Collapse
Affiliation(s)
- Vasvi Chaudhry
- Bacterial Genomics and Evolution Laboratory, CSIR-Institute of Microbial Technology, Sector - 39A, Chandigarh 160036, India
| | - Prabhu B Patil
- Bacterial Genomics and Evolution Laboratory, CSIR-Institute of Microbial Technology, Sector - 39A, Chandigarh 160036, India.
| |
Collapse
|
7
|
Novel Probiotic Mechanisms of the Oral Bacterium Streptococcus sp. A12 as Explored with Functional Genomics. Appl Environ Microbiol 2019; 85:AEM.01335-19. [PMID: 31420345 DOI: 10.1128/aem.01335-19] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Accepted: 08/14/2019] [Indexed: 12/11/2022] Open
Abstract
Health-associated biofilms in the oral cavity are composed of a diverse group of microbial species that can foster an environment that is less favorable for the outgrowth of dental caries pathogens, like Streptococcus mutans A novel oral bacterium, designated Streptococcus A12, was previously isolated from supragingival dental plaque of a caries-free individual and was shown to interfere potently with the growth and virulence properties of S. mutans In this study, we applied functional genomics to begin to identify molecular mechanisms used by A12 to antagonize, and to resist the antagonistic factors of, S. mutans Using bioinformatics, genes that could encode factors that enhance the ability of A12 to compete with S. mutans were identified. Selected genes, designated potential competitive factors (pcf), were deleted. Certain mutant derivatives showed a reduced capacity to compete with S. mutans compared to that of the parental strain. The A12 pcfO mutant lost the ability to inhibit comX -inducing peptide (XIP) signaling by S. mutans, while mutants with changes in the pcfFEG locus were impaired in sensing of, and were more sensitive to, the lantibiotic nisin. Loss of PcfV, annotated as a colicin V biosynthetic protein, resulted in diminished antagonism of S. mutans Collectively, the data provide new insights into the complexities and variety of factors that affect biofilm ecology and virulence. Continued exploration of the genomic and physiological factors that distinguish commensals from truly beneficial members of the oral microbiota will lead to a better understanding of the microbiome and new approaches to promote oral health.IMPORTANCE Advances in defining the composition of health-associated biofilms have highlighted the important role of beneficial species in maintaining health. Comparatively little, however, has been done to address the genomic and physiological bases underlying the probiotic mechanisms of beneficial commensals. In this study, we explored the ability of a novel oral bacterial isolate, Streptococcus A12, to compete with the dental pathogen Streptococcus mutans using various gene products with diverse functions. A12 displayed enhanced competitiveness by (i) disrupting intercellular communication pathways of S. mutans, (ii) sensing and resisting antimicrobial peptides, and (iii) producing factors involved in the production of a putative antimicrobial compound. Research on the probiotic mechanisms employed by Streptococcus A12 is providing essential insights into how beneficial bacteria may help maintain oral health, which will aid in the development of biomarkers and therapeutics that can improve the practice of clinical dentistry.
Collapse
|
8
|
Chen Y, Hammer EE, Richards VP. Phylogenetic signature of lateral exchange of genes for antibiotic production and resistance among bacteria highlights a pattern of global transmission of pathogens between humans and livestock. Mol Phylogenet Evol 2018; 125:255-264. [DOI: 10.1016/j.ympev.2018.03.034] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Revised: 03/27/2018] [Accepted: 03/29/2018] [Indexed: 01/08/2023]
|
9
|
Bao Y, Tian M, Li P, Liu J, Ding C, Yu S. Characterization of Brucella abortus mutant strain Δ22915, a potential vaccine candidate. Vet Res 2017; 48:17. [PMID: 28376905 PMCID: PMC5381064 DOI: 10.1186/s13567-017-0422-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Accepted: 03/07/2017] [Indexed: 11/25/2022] Open
Abstract
Brucellosis, caused by Brucella spp., is an important zoonosis worldwide. Vaccination is an effective strategy for protection against Brucella infection in livestock in developing countries and in wildlife in developed countries. However, current vaccine strains including S19 and RB51 are pathogenic to humans and pregnant animals, limiting their use. In this study, we constructed the Brucella abortus (B. abortus) S2308 mutant strain Δ22915, in which the putative lytic transglycosylase gene BAB_RS22915 was deleted. The biological properties of mutant strain Δ22915 were characterized and protection of mice against virulent S2308 challenge was evaluated. The mutant strain Δ22915 showed reduced survival within RAW264.7 cells and survival in vivo in mice. In addition, the mutant strain Δ22915 failed to escape fusion with lysosomes within host cells, and caused no observable pathological damage. RNA-seq analysis indicated that four genes associated with amino acid/nucleotide transport and metabolism were significantly upregulated in mutant strain Δ22915. Furthermore, inoculation of ∆22915 at 105 colony forming units induced effective host immune responses and long-term protection of BALB/c mice. Therefore, mutant strain ∆22915 could be used as a novel vaccine candidate in the future to protect animals against B. abortus infection.
Collapse
Affiliation(s)
- Yanqing Bao
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Shanghai, China
| | - Mingxing Tian
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Shanghai, China
| | - Peng Li
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Shanghai, China
| | - Jiameng Liu
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Shanghai, China
| | - Chan Ding
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Shanghai, China
| | - Shengqing Yu
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Shanghai, China
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, China
| |
Collapse
|
10
|
Maricic N, Anderson ES, Opipari AE, Yu EA, Dawid S. Characterization of a Multipeptide Lantibiotic Locus in Streptococcus pneumoniae. mBio 2016; 7:e01656-15. [PMID: 26814178 PMCID: PMC4742701 DOI: 10.1128/mbio.01656-15] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Accepted: 12/28/2015] [Indexed: 12/14/2022] Open
Abstract
UNLABELLED Bacterial communities are established through a combination of cooperative and antagonistic interactions between the inhabitants. Competitive interactions often involve the production of antimicrobial substances, including bacteriocins, which are small antimicrobial peptides that target other community members. Despite the nearly ubiquitous presence of bacteriocin-encoding loci, inhibitory activity has been attributed to only a small fraction of gene clusters. In this study, we characterized a novel locus (the pld locus) in the pathogen Streptococcus pneumoniae that drives the production of a bacteriocin called pneumolancidin, which has broad antimicrobial activity. The locus encodes an unusual tandem array of four inhibitory peptides, three of which are absolutely required for antibacterial activity. The three peptide sequences are similar but appear to play distinct roles in regulation and inhibition. A modification enzyme typically found in loci encoding a class of highly modified bacteriocins called lantibiotics was required for inhibitory activity. The production of pneumolancidin is controlled by a two-component regulatory system that is activated by the accumulation of modified peptides. The locus is located on a mobile element that has been found in many pneumococcal lineages, although not all elements carry the pld genes. Intriguingly, a minimal region containing only the genes required for pneumolancidin immunity was found in several Streptococcus mitis strains. The pneumolancidin-producing strain can inhibit nearly all pneumococci tested to date and provided a competitive advantage in vivo. These peptides not only represent a unique strategy for bacterial competition but also are an important resource to guide the development of new antimicrobials. IMPORTANCE Successful colonization of a polymicrobial host surface is a prerequisite for the subsequent development of disease for many bacterial pathogens. Bacterial factors that directly inhibit the growth of neighbors may provide an advantage during colonization if the inhibition of competitors outweighs the energy for production. In this work, we found that production of a potent antimicrobial called pneumolancidin conferred a competitive advantage to the pathogen Streptococcus pneumoniae. S. pneumoniae secreting pneumolancidin inhibits a wide array of Gram-positive organisms, including all but one tested pneumococcal strain. The pneumolancidin genetic locus is of particular interest because it encodes three similar modified peptides (lantibiotics), each of which has a distinct role in the function of the locus. Lantibiotics represent a relatively untapped resource for the development of clinically useful antibiotics which are desperately needed. The broad inhibitory activity of pneumolancidin makes it an ideal candidate for further characterization and development.
Collapse
Affiliation(s)
- Natalie Maricic
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, Michigan, USA
| | - Erica S Anderson
- Department of Pediatrics and Communicable Diseases, University of Michigan, Ann Arbor, Michigan, USA
| | - AnneMarie E Opipari
- Department of Pediatrics and Communicable Diseases, University of Michigan, Ann Arbor, Michigan, USA
| | - Emily A Yu
- Department of Pediatrics and Communicable Diseases, University of Michigan, Ann Arbor, Michigan, USA
| | - Suzanne Dawid
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, Michigan, USA Department of Pediatrics and Communicable Diseases, University of Michigan, Ann Arbor, Michigan, USA
| |
Collapse
|
11
|
Biosynthesis and transport of the lantibiotic mutacin 1140 produced by Streptococcus mutans. J Bacteriol 2015; 197:1173-84. [PMID: 25605307 DOI: 10.1128/jb.02531-14] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Lantibiotics are ribosomally synthesized peptide antibiotics composed of an N-terminal leader peptide that is cleaved to yield the active antibacterial peptide. Significant advancements in molecular tools that promote the study of lantibiotic biosynthesis can be used in Streptococcus mutans. Herein, we further our understanding of leader peptide sequence and core peptide structural requirements for the biosynthesis and transport of the lantibiotic mutacin 1140. Our study on mutacin 1140 biosynthesis shows a dedicated secondary cleavage site within the leader peptide and the dependency of transport on core peptide posttranslational modifications (PTMs). The secondary cleavage site on the leader peptide is found at the -9 position, and secondary cleavage occurs before the core peptide is transported out of the cell. The coordinated cleavage at the -9 position was absent in a lanT deletion strain, suggesting that the core peptide interaction with the LanT transporter enables uniform cleavage at the -9 position. Following transport, the LanP protease was found to be tolerant to a wide variety of amino acid substitutions at the primary leader peptide cleavage site, with the exception of arginine at the -1 position. Several leader and core peptide mutations produced core peptide variants that had intermediate stages of PTM enzyme modifications, supporting the concept that PTM enzyme modifications, secondary cleavage, and transport are occurring in a highly coordinated fashion. IMPORTANCE Mutacin 1140 belongs to the class I lantibiotic family of ribosomally synthesized and posttranslationally modified peptides (RiPPs). The biosynthesis of mutacin 1140 is a highly efficient process which does not lead to a discernible level of production of partially modified core peptide variants. The products isolated from an extensive mutagenesis study on the leader and core peptides of mutacin 1140 show that the posttranslational modifications (PTMs) on the core peptide occur under a highly coordinated dynamic process. PTMs are dictated by the distance of the core peptide modifiable residues from PTM enzyme active sites. The formation of lanthionine rings aids in the formation of successive PTMs, as was observed in a peptide variant lacking a C-terminal decarboxylation.
Collapse
|
12
|
Nawrocki KL, Crispell EK, McBride SM. Antimicrobial Peptide Resistance Mechanisms of Gram-Positive Bacteria. Antibiotics (Basel) 2014; 3:461-92. [PMID: 25419466 PMCID: PMC4239024 DOI: 10.3390/antibiotics3040461] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2014] [Revised: 09/25/2014] [Accepted: 09/28/2014] [Indexed: 01/09/2023] Open
Abstract
Antimicrobial peptides, or AMPs, play a significant role in many environments as a tool to remove competing organisms. In response, many bacteria have evolved mechanisms to resist these peptides and prevent AMP-mediated killing. The development of AMP resistance mechanisms is driven by direct competition between bacterial species, as well as host and pathogen interactions. Akin to the number of different AMPs found in nature, resistance mechanisms that have evolved are just as varied and may confer broad-range resistance or specific resistance to AMPs. Specific mechanisms of AMP resistance prevent AMP-mediated killing against a single type of AMP, while broad resistance mechanisms often lead to a global change in the bacterial cell surface and protect the bacterium from a large group of AMPs that have similar characteristics. AMP resistance mechanisms can be found in many species of bacteria and can provide a competitive edge against other bacterial species or a host immune response. Gram-positive bacteria are one of the largest AMP producing groups, but characterization of Gram-positive AMP resistance mechanisms lags behind that of Gram-negative species. In this review we present a summary of the AMP resistance mechanisms that have been identified and characterized in Gram-positive bacteria. Understanding the mechanisms of AMP resistance in Gram-positive species can provide guidelines in developing and applying AMPs as therapeutics, and offer insight into the role of resistance in bacterial pathogenesis.
Collapse
Affiliation(s)
- Kathryn L Nawrocki
- Department of Microbiology and Immunology, Emory University School of Medicine, 1510 Clifton Rd, Atlanta, GA 30322, USA; (K.L.N.); (E.K.C.)
| | - Emily K Crispell
- Department of Microbiology and Immunology, Emory University School of Medicine, 1510 Clifton Rd, Atlanta, GA 30322, USA; (K.L.N.); (E.K.C.)
| | - Shonna M McBride
- Department of Microbiology and Immunology, Emory University School of Medicine, 1510 Clifton Rd, Atlanta, GA 30322, USA; (K.L.N.); (E.K.C.)
| |
Collapse
|
13
|
A conserved streptococcal membrane protein, LsrS, exhibits a receptor-like function for lantibiotics. J Bacteriol 2014; 196:1578-87. [PMID: 24509319 DOI: 10.1128/jb.00028-14] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Streptococcus mutans strain GS-5 produces a two-peptide lantibiotic, Smb, which displays inhibitory activity against a broad spectrum of bacteria, including other streptococci. For inhibition, lantibiotics must recognize specific receptor molecules present on the sensitive bacterial cells. However, so far no such receptor proteins have been identified for any lantibiotics. In this study, using a powerful transposon mutagenesis approach, we have identified in Streptococcus pyogenes a gene that exhibits a receptor-like function for Smb. The protein encoded by that gene, which we named LsrS, is a membrane protein belonging to the CAAX protease family. We also found that nisin, a monopeptide lantibiotic, requires LsrS for its optimum inhibitory activity. However, we found that LsrS is not required for inhibition by haloduracin and galolacticin, both of which are two-peptide lantibiotics closely related to Smb. LsrS appears to be a well-conserved protein that is present in many streptococci, including S. mutans. Inactivation of SMU.662, an LsrS homolog, in S. mutans strains UA159 and V403 rendered the cells refractory to Smb-mediated killing. Furthermore, overexpression of LsrS in S. mutans created cells more susceptible to Smb. Although LsrS and its homolog contain the CAAX protease domain, we demonstrate that inactivation of the putative active sites on the LsrS protein has no effect on its receptor-like function. This is the first report describing a highly conserved membrane protein that displays a receptor-like function for lantibiotics.
Collapse
|
14
|
Jakubovics NS, Yassin SA, Rickard AH. Community interactions of oral streptococci. ADVANCES IN APPLIED MICROBIOLOGY 2014; 87:43-110. [PMID: 24581389 DOI: 10.1016/b978-0-12-800261-2.00002-5] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
It is now clear that the most common oral diseases, dental caries and periodontitis, are caused by mixed-species communities rather than by individual pathogens working in isolation. Oral streptococci are central to these disease processes since they are frequently the first microorganisms to colonize oral surfaces and they are numerically the dominant microorganisms in the human mouth. Numerous interactions between oral streptococci and other bacteria have been documented. These are thought to be critical for the development of mixed-species oral microbial communities and for the transition from oral health to disease. Recent metagenomic studies are beginning to shed light on the co-occurrence patterns of streptococci with other oral bacteria. Refinements in microscopy techniques and biofilm models are providing detailed insights into the spatial distribution of streptococci in oral biofilms. Targeted genetic manipulation is increasingly being applied for the analysis of specific genes and networks that modulate interspecies interactions. From this work, it is clear that streptococci produce a range of extracellular factors that promote their integration into mixed-species communities and enable them to form social networks with neighboring taxa. These "community integration factors" include coaggregation-mediating adhesins and receptors, small signaling molecules such as peptides or autoinducer-2, bacteriocins, by-products of metabolism including hydrogen peroxide and lactic acid, and a range of extracellular enzymes. Here, we provide an overview of various types of community interactions between oral streptococci and other microorganisms, and we consider the possibilities for the development of new technologies to interfere with these interactions to help control oral biofilms.
Collapse
Affiliation(s)
- Nicholas S Jakubovics
- Oral Biology, School of Dental Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom.
| | - Sufian A Yassin
- Oral Biology, School of Dental Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Alexander H Rickard
- Department of Epidemiology, School of Public Health, University of Michigan, Ann Arbor, Michigan, USA
| |
Collapse
|