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Malesevic M, Gardijan L, Miljkovic M, O'Connor PM, Mirkovic N, Jovcic B, Cotter PD, Jovanovic G, Kojic M. Exploring the antibacterial potential of Lactococcus lactis subsp. lactis bv. diacetylactis BGBU1-4 by genome mining, bacteriocin gene overexpression, and chemical protein synthesis of lactolisterin BU variants. Lett Appl Microbiol 2023; 76:6986262. [PMID: 36695436 DOI: 10.1093/lambio/ovad004] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 12/09/2022] [Accepted: 01/11/2023] [Indexed: 01/15/2023]
Abstract
Lactic acid bacterium Lactococcus lactis BGBU1-4 produces 43 amino acids (aa) long bacteriocin, lactolisterin BU (LBU), a 5.161 kDa peptide with potent antibacterial activity against many Gram-positive pathogens. In addition, BGBU1-4 produces an additional unknown product of 3.642 kDa with antibacterial activity. Here, we determined that the significant amount of naturally produced LBU breaks down to create a 3.642 kDa truncated form of LBU bacteriocin consisting of 31 N-terminal aa (LBU1-31) that exhibits 12.5% the antibacterial activity of the full-length LBU. We showed that chemically synthesized LBU is stable and 50% less active than native LBU, and so we used the synthetic peptides of LBU and its variants to further study their activities and antibacterial potential. Deletion analysis of LBU revealed that the 24 N-terminal aa of LBU (LBU1-24) are responsible for antibacterial activity, while downstream aa (25-43) determine the species-specific effectiveness of LBU. Although LBU1-31 contains aa 1-24, the truncation at position 31 is predicted to change the structure within aa 15-31 and might impact on antibacterial activity. Intriguingly, whole genome sequencing and genome mining established that BGBU1-4 is abundant in genes that encode potential antibacterials, but produces LBU and its breakdown product LBU1-31 exclusively.
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Affiliation(s)
- Milka Malesevic
- Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, 444a Vojvode Stepe, Belgrade, Serbia
| | - Lazar Gardijan
- Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, 444a Vojvode Stepe, Belgrade, Serbia
| | - Marija Miljkovic
- Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, 444a Vojvode Stepe, Belgrade, Serbia
| | - Paula M O'Connor
- Teagasc Food Research Centre, Moorepark, Fermoy, Co. Cork, P61 C996, Ireland.,APC Microbiome Ireland, Cork D03 E5R6, Ireland
| | - Nemanja Mirkovic
- Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, 444a Vojvode Stepe, Belgrade, Serbia
| | - Branko Jovcic
- Faculty of Biology, University of Belgrade, Beograd 11000, Serbia.,Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, 444a Vojvode Stepe, Belgrade, Serbia
| | - Paul D Cotter
- Teagasc Food Research Centre, Moorepark, Fermoy, Co. Cork, P61 C996, Ireland.,APC Microbiome Ireland, Cork D03 E5R6, Ireland
| | - Goran Jovanovic
- Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, 444a Vojvode Stepe, Belgrade, Serbia
| | - Milan Kojic
- Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, 444a Vojvode Stepe, Belgrade, Serbia
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Isolation, Characterization, and Effect on Biofilm Formation of Bacteriocin Produced by Lactococcus lactis F01 Isolated from Cyprinus carpio and Application for Biopreservation of Fish Sausage. BIOMED RESEARCH INTERNATIONAL 2022; 2022:8437926. [DOI: 10.1155/2022/8437926] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2022] [Revised: 10/18/2022] [Accepted: 11/03/2022] [Indexed: 11/23/2022]
Abstract
The aim of this work was the screening of bacteriocin-producing LABs isolated from fish, the selection of promising/prominent strain(s), the characterization of the bacteriocin produced, and the evaluation of its potential to be used as biopreservative(s). Amplification and sequencing of the 16S rRNA gene of the bacteriocin-producing strain was performed. Then a partial purification of the produced bacteriocin, using a combination of ammonium sulfate and chloroform-methanol precipitation, was done. Its molecular weight was determined by SDS-PAGE. In addition, the action spectrum, the hemolysis test, and its ability to inhibit biofilm formation were analyzed. A total of 88 isolates of lactic acid bacteria (LAB) including one bacteriocin producer, which was identified as Lactococcus lactis F01, were collected. The bacteriocin was partially purified with an estimated yield of 40%. Regarding the SDS-PAGE profile, the secreted bacteriocin has molecular weight of about 3.5 kDa and was identified as class I bacteriocin. The antimicrobial test showed that the bacteriocin inhibits pathogenic and/or spoilage bacteria, 10 Gram-positive and 16 Gram-negative bacterial species. Moreover, it can inhibit biofilm formation from 1.3% (Escherichia coli) to 63.92% (Pseudomonas aeruginosa ATCC15692) depending on the strain. The hemolytic activity of novel bacteriocin was observed at the concentration of 10 μg/ml of bacteriocin crude extract, which was
. In addition, it exhibited good thermal and pH stability with retained antibacterial activity of 85.25% after treatment at 121°C for 20 min, as well as at a pH range between 2.0 and 10.0. Moreover, this bacteriocin showed the ability to inhibit the growth of bacterial culture load in fish sausage stored at 8°C for 28 days. Considering the results obtained, bacteriocin could be potentially exploited as an alternative to chemical preservatives or as a substitute for antibiotics.
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Song Q, Wu H, Zhang P, Tian K, Zhu H, Qiao J. LssR plays a positive regulatory role in acid and nisin tolerance response of Lactococcus lactis. J Dairy Sci 2022; 105:6483-6498. [PMID: 35840402 DOI: 10.3168/jds.2022-21842] [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: 01/19/2022] [Accepted: 04/14/2022] [Indexed: 11/19/2022]
Abstract
In Lactococcus lactis, different regulation mechanisms can be activated to overcome the effects of adverse environmental stresses. Here, a TetR family regulator LssR was demonstrated as a positive regulator in the activation of the mechanisms involved in acid and nisin tolerance of L. lactis. The deletion of lssR led to the reduction of tolerance of L. lactis NZ9000 to nisin and acid stress, and the survival rates of NZ9000 under nisin and acid stress were roughly 20-fold, 10-fold (pH 3.0, hydrochloric acid), and 8.9-fold (pH 4.0, lactic acid) of the lssR mutant NZΔlssR, respectively. Moreover, the lssR mutant NZΔlssR also displayed a lower intracellular pH stability and a changed cell surface morphology. Subsequently, transcriptome analysis revealed that genes related to the arginine deiminase pathway, the surface polysaccharides biosynthesis, carbohydrates transport and metabolism, multidrug resistance, cell repair proteins and chaperones were predominantly down transcribed in NZΔlssR. The transcript levels of the arginine deiminase pathway and the surface polysaccharides biosynthesis-associated genes under acid and nisin stresses were compared between the wild type NZ9000 and NZΔlssR using real-time fluorescence quantitative PCR. It revealed that the arginine deiminase pathway genes (arcD1C1C2T) and the surface polysaccharides biosynthesis genes (cgT, gmhB, gmhA, hddA, tagH and tarS) were proposed to be the main regulatory mechanisms of LssR in response to the acid and nisin stresses. Overall, the important role of LssR in the acid and nisin stresses response was demonstrated and the putative regulation mechanism of LssR was revealed.
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Affiliation(s)
- Qianqian Song
- Department of Pharmaceutical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
| | - Hao Wu
- Department of Pharmaceutical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China; Zhejiang Shaoxing Research Institute of Tianjin University, Shaoxing 312300, China
| | - Peng Zhang
- Department of Pharmaceutical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
| | - Kairen Tian
- Department of Pharmaceutical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
| | - Hongji Zhu
- Department of Pharmaceutical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China.
| | - Jianjun Qiao
- Department of Pharmaceutical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China; Zhejiang Shaoxing Research Institute of Tianjin University, Shaoxing 312300, China; Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin 300072, China; SynBio Research Platform Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin 300072, China.
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Gardijan L, Miljkovic M, Obradovic M, Borovic B, Vukotic G, Jovanovic G, Kojic M. Redesigned pMAL expression vector for easy and fast purification of active native antimicrobial peptides. J Appl Microbiol 2022; 133:1001-1013. [PMID: 35578999 DOI: 10.1111/jam.15623] [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: 12/19/2021] [Revised: 05/05/2022] [Accepted: 05/12/2022] [Indexed: 11/28/2022]
Abstract
AIMS The aim of this study was to construct the improved pMAL expression vector in order to increase the efficacy of small native peptides purification and their clear-cut separation from MBP tag. The modifications we introduced can be applied to many expression vectors. METHODS AND RESULTS To improve the pMAL expression vector we introduced the His6 tag and the enterokinase cleavage site (Ek) downstream from the MBP tag and Xa cleavage site on the original vector. For cloning of a desired peptide DNA, the enterokinase site contains a unique BsaBI restriction site adjacent to the original multi-cloning-site. This redesigned pMAL vector was optimized for the purification of cytoplasmic (pMALc5HisEk) and periplasmic (pMALp5HisEk) peptides. The purification of native and active peptide (P) was obtained following two-step affinity chromatography. In the first step the entire MBP-His6 -Ek-P fusion protein is purified using the Ni-NTA agarose column. This fusion protein was cleaved with active His6 tagged enterokinase. In the second step, the further purification was performed by column containing the mixture of amylose and Ni-NTA agarose resins. This removes both the MBP-His6 and His6 -enterokinase leaving pure native protein in solution. These new vectors and the two-step purification protocol was successfully applied in purification of active native small antimicrobial peptides (AMPs), lactococcin A and human β-defensin. CONCLUSIONS We constructed the improved pMAL expression vectors and established the pipeline and optimal conditions for their use in efficient purification of large amounts of active native small peptides. SIGNIFICANCE AND IMPACT OF THE STUDY Choice of expression vector impacts on the efficiency of expression and purification of desired proteins. The idea of redesigning pMAL vector was driven by need for rapid purification of larger amounts of active native AMPs. This newly improved pMAL vector, the cloning strategy, expression conditions and two-step purification protocol represent a unique simple approach which can be applied in every laboratory.
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Affiliation(s)
- Lazar Gardijan
- Laboratory for Molecular Microbiology, Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Vojvode Stepe 444/a, Belgrade, Serbia
| | - Marija Miljkovic
- Laboratory for Molecular Microbiology, Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Vojvode Stepe 444/a, Belgrade, Serbia
| | - Mina Obradovic
- Laboratory for Molecular Microbiology, Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Vojvode Stepe 444/a, Belgrade, Serbia
| | - Branka Borovic
- Institute of Meat Hygiene and Technology, Kaćanskog 13, Belgrade, Serbia
| | - Goran Vukotic
- Laboratory for Molecular Microbiology, Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Vojvode Stepe 444/a, Belgrade, Serbia.,Faculty of Biology, University of Belgrade, Studentskitrg16, Belgrade, Serbia
| | - Goran Jovanovic
- Laboratory for Molecular Microbiology, Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Vojvode Stepe 444/a, Belgrade, Serbia
| | - Milan Kojic
- Laboratory for Molecular Microbiology, Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Vojvode Stepe 444/a, Belgrade, Serbia
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The large plasmidome of Lactococcus lactis subsp. lactis bv. diacetylactis S50 confers its biotechnological properties. Int J Food Microbiol 2020; 337:108935. [PMID: 33152568 DOI: 10.1016/j.ijfoodmicro.2020.108935] [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: 06/13/2020] [Revised: 10/09/2020] [Accepted: 10/13/2020] [Indexed: 01/17/2023]
Abstract
Plasmids are autonomous episomally replicating genetic elements, which carry backbone genes important for the replication and maintenance within their host, and accessory genes that might confer an advantage to their host under specific selective pressure in its ecological niche. The genome of dairy isolate L. lactis subsp. lactis bv. diacetylactis S50 was sequenced using the PacBio SMRT Cell Seq-RSII platform and revealed to possess one of the largest plasmidomes among L. lactis strains studied so far, harboring six plasmids: pS6 (5553 bp), pS7a (7308 bp), pS7b (7266 bp), pS19 (19,027 bp), pS74 (74,256 bp) and pS127 (127,002 bp) in total representing 8.9% of genome size (240,412 bp). Based on predicted plasmid replication proteins and origins it appears that all six plasmids replicate via the theta-type mechanism. The two the largest plasmids (pS74 and pS127), carry a number of genes known to be important for growth and survival in the dairy environment. These genes encode technological functions such as bacteriocin production, protein degradation, magnesium and cobalt/nickel transporters, selenium binding, exopolysaccharides (EPS) production, bacteriophage and stress resistance. Beside genes for replication, the small plasmids (pS6, pS7a, pS7a, and pS19) also carry genes important for mobilization and host survival such as type I restriction-modification (R-M) system, metal transporters, enzymes and transcriptional regulators. All plasmids in S50 strain are mobilizable, containing an oriT sequences, while pS127 is self-conjugative and allows for mobilization of the other plasmids. Small plasmids are prone to structural and segregational instability, while pS127 appeared to be segregationally stable thanks to the possession of two partition systems. The main characteristic of plasmid pS74 is EPS production, while plasmid pS127 is characterized by proteinase and multiple bacteriocins, tra locus, phage abortive systems and metal transporters. In addition to LcnA and LcnB, plasmid pS127 encodes several bacteriocin-pheromone molecules and a new bacteriocin named LcnS50, with narrow spectrum of action limited to lactococci, that has been successfully cloned and heterologously expressed.
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Kojic M, Jovcic B, Miljkovic M, Novovic K, Begovic J, Studholme DJ. Large-scale chromosome flip-flop reversible inversion mediates phenotypic switching of expression of antibiotic resistance in lactococci. Microbiol Res 2020; 241:126583. [PMID: 32919223 DOI: 10.1016/j.micres.2020.126583] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 08/14/2020] [Accepted: 08/15/2020] [Indexed: 11/26/2022]
Abstract
Bacteria can gain resistance to antimicrobials by acquiring and expressing genetic elements that encode resistance determinants such as efflux pumps and drug-modifying enzymes, thus hampering treatment of infection. Previously we showed that acquisition of spectinomycin resistance in a lactococcal strain was correlated with a reversible genomic inversion, but the precise location and the genes affected were unknown. Here we use long-read whole-genome sequencing to precisely define the genomic inversion and we use quantitative PCR to identify associated changes in gene expression levels. The boundaries of the inversion fall within two identical copies of a prophage-like sequence, located on the left and right replichores; this suggests possible mechanisms for inversion through homologous recombination or prophage activity. The inversion is asymmetrical in respect of the axis between the origin and terminus of the replication and modulates the expression of a SAM-dependent methyltransferase, whose heterologous expression confers resistance to spectinomycin in lactococci and that is up-regulated on exposure to spectinomycin. This study provides one of the first examples of phase variation via large-scale chromosomal inversions that confers a switch in antimicrobial resistance in bacteria and the first outside of Staphylococcus aureus.
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Affiliation(s)
- Milan Kojic
- Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Belgrade, Serbia.
| | - Branko Jovcic
- Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Belgrade, Serbia; Faculty of Biology, University of Belgrade, Belgrade, Serbia
| | - Marija Miljkovic
- Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Belgrade, Serbia
| | - Katarina Novovic
- Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Belgrade, Serbia
| | - Jelena Begovic
- Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Belgrade, Serbia
| | - David J Studholme
- Biosciences, College of Life and Environmental Sciences, University of Exeter, Stocker Road, Exeter, EX4 4QD, UK
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Miljkovic M, Jovanovic S, O’Connor PM, Mirkovic N, Jovcic B, Filipic B, Dinic M, Studholme DJ, Fira D, Cotter PD, Kojic M. Brevibacillus laterosporus strains BGSP7, BGSP9 and BGSP11 isolated from silage produce broad spectrum multi-antimicrobials. PLoS One 2019; 14:e0216773. [PMID: 31075157 PMCID: PMC6510442 DOI: 10.1371/journal.pone.0216773] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Accepted: 04/30/2019] [Indexed: 12/26/2022] Open
Abstract
Bacteria active against multi-drug resistant pathogens, isolated by direct selection of colonies from clover silage samples, produce zones of inhibition against two Gram-negative (Klebsiella pneumoniae Ni9 and Pseudomonas aeruginosa MMA83) and two Gram-positive (Staphylococcus aureus ATCC25923 and Listeria monocytogenes ATCC19111) pathogens. Isolates BGSP7, BGSP9, BGSP11 and BGSP12 produced the largest zones of inhibition against all four pathogens when grown in LB broth with aeration at 37°C. Isolates BGSP7, BGSP9, BGSP11 and BGSP12 were identified as Brevibacillus laterosporus and pulsed field gel electrophoresis and extracellular protein profiles showed that three different strains (BGSP7, BGSP9 and BGSP11) were isolated. A semi-native SDS-PAGE (sodium dodecyl sulphate-polyacrylamide gel electrophoresis) gel overlay assay showed that BGSP7 and BGSP9 produce small antimicrobial molecules of about 1.5 kDa, while BGSP11 produces antimicrobial molecules of 1.5 and 6 kDa active against S. aureus ATCC25923. Amino acid analysis of two antimicrobial molecules (1583.73 Da; from BGSP7 and 1556.31 Da; from BGSP11) revealed that they have a similar composition and differ only by virtue of the presence of a methionine which is present only in BGSP11 molecule. Genome sequencing of the three isolates revealed the presence of gene clusters associated with the production of non-ribosomally synthesized peptides (brevibacillin, bogorol, gramicidin S, plipastatin and tyrocin) and bacteriocins (laterosporulin, a lactococcin 972-like bacteriocin, as well as putative linocin M18, sactipeptide, UviB and lantipeptide-like molecules). Ultimately, the purification of a number of antimicrobial molecules from each isolate suggests that they can be considered as potent biocontrol strains that produce an arsenal of antimicrobial molecules active against Gram-positive and Gram-negative multi-resistant pathogens, fungi and insects.
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Affiliation(s)
- Marija Miljkovic
- Laboratory for Molecular Microbiology, Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Belgrade, Serbia
| | - Sofija Jovanovic
- Laboratory for Molecular Microbiology, Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Belgrade, Serbia
| | - Paula M. O’Connor
- Teagasc Food Research Centre, Moorepark, Fermoy, Ireland
- APC Microbiome Ireland, Cork, Ireland
| | - Nemanja Mirkovic
- Laboratory for Molecular Microbiology, Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Belgrade, Serbia
| | - Branko Jovcic
- Laboratory for Molecular Microbiology, Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Belgrade, Serbia
- Faculty of Biology, University of Belgrade, Belgrade, Serbia
| | - Brankica Filipic
- Laboratory for Molecular Microbiology, Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Belgrade, Serbia
- Faculty of Pharmacy, University of Belgrade, Belgrade, Serbia
| | - Miroslav Dinic
- Laboratory for Molecular Microbiology, Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Belgrade, Serbia
| | - David John Studholme
- Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, United Kingdom
| | - Djordje Fira
- Laboratory for Molecular Microbiology, Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Belgrade, Serbia
- Faculty of Biology, University of Belgrade, Belgrade, Serbia
| | - Paul D. Cotter
- Teagasc Food Research Centre, Moorepark, Fermoy, Ireland
- APC Microbiome Ireland, Cork, Ireland
| | - Milan Kojic
- Laboratory for Molecular Microbiology, Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Belgrade, Serbia
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