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Kato K, Serata M, Nakamura M, Ando M, Suzuki T, Okumura T. Cell wall polysaccharide enhances Lacticaseibacillus paracasei strain Shirota growth in milk and contributes to acid and bile tolerance. Int J Food Microbiol 2024; 422:110811. [PMID: 39018886 DOI: 10.1016/j.ijfoodmicro.2024.110811] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2024] [Revised: 06/03/2024] [Accepted: 06/23/2024] [Indexed: 07/19/2024]
Abstract
LCPS-1, a cell wall polysaccharide (CWPS), is bound to the cell wall of the probiotic Lacticaseibacillus paracasei (formerly known as Lactobacillus casei) strain Shirota (LcS). Generally, the role of CWPS in the viability and survivability of bacteria is yet to be fully understood. This study aimed to elucidate the role of LCPS-1 in the viability and survivability of LcS. A mutant strain completely lacking LCPS-1 was constructed and evaluated for growth in bovine and soy milk and susceptibility to acid and bile. The growth of the mutant in bovine and soy milk temporarily stalled after the late logarithmic phase while wild-type LcS continued growing, resulting in a significantly lower number of viable cells for the mutant strain (p < 0.01). Significantly higher cell death relative to that of the wild-type strain was observed for the mutant strain following acid treatment at pH 3.0 (p < 0.01), with 60 and 92 % survival, respectively. The absence of LCPS-1 also reduced the survival rate of LcS cells from 3.3 to 0.8 % following 0.2 % bile treatment. The survival rate of the mutant after consecutive treatment with acid and bile was 19 %, while 73 % of the wild-type LcS survived. These results indicate that LCPS-1 leads to higher LcS growth in milk and improves tolerance to acid and bile. This study reveals the contribution of probiotic bacterial CWPS to acidic and gastrointestinal stress tolerance. Based on these findings, characterizing and modifying CWPS in probiotic strains could enhance manufacturing yields and improve gastrointestinal stress tolerance after consumption by hosts, ultimately advancing the development of more effective probiotics.
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Affiliation(s)
- Kosuke Kato
- Yakult Central Institute, 5-11 Izumi Kunitachi-shi, Tokyo 186-8650, Japan.
| | - Masaki Serata
- Yakult Central Institute, 5-11 Izumi Kunitachi-shi, Tokyo 186-8650, Japan
| | - Madoka Nakamura
- Yakult Central Institute, 5-11 Izumi Kunitachi-shi, Tokyo 186-8650, Japan
| | - Minoru Ando
- Yakult Central Institute, 5-11 Izumi Kunitachi-shi, Tokyo 186-8650, Japan
| | - Tomo Suzuki
- Yakult Central Institute, 5-11 Izumi Kunitachi-shi, Tokyo 186-8650, Japan
| | - Takekazu Okumura
- Yakult Central Institute, 5-11 Izumi Kunitachi-shi, Tokyo 186-8650, Japan
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2
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Mokhtari S, Li Y, Saris PEJ, Takala TM. Analysis of the cell wall binding domain in bacteriocin-like lysin LysL from Lactococcus lactis LAC460. Arch Microbiol 2024; 206:336. [PMID: 38954047 PMCID: PMC11219366 DOI: 10.1007/s00203-024-04066-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2024] [Revised: 06/19/2024] [Accepted: 06/21/2024] [Indexed: 07/04/2024]
Abstract
Wild-type Lactococcus lactis strain LAC460 secretes prophage-encoded bacteriocin-like lysin LysL, which kills some Lactococcus strains, but has no lytic effect on the producer. LysL carries two N-terminal enzymatic active domains (EAD), and an unknown C-terminus without homology to known domains. This study aimed to determine whether the C-terminus of LysL carries a cell wall binding domain (CBD) for target specificity of LysL. The C-terminal putative CBD region of LysL was fused with His-tagged green fluorescent protein (HGFPuv). The HGFPuv_CBDlysL gene fusion was ligated into the pASG-IBA4 vector, and introduced into Escherichia coli. The fusion protein was produced and purified with affinity chromatography. To analyse the binding of HGFPuv_CBDLysL to Lactococcus cells, the protein was mixed with LysL-sensitive and LysL-resistant strains, including the LysL-producer LAC460, and the fluorescence of the cells was analysed. As seen in fluorescence microscope, HGFPuv_CBDLysL decorated the cell surface of LysL-sensitive L. cremoris MG1614 with green fluorescence, whereas the resistant L. lactis strains LM0230 and LAC460 remained unfluorescent. The fluorescence plate reader confirmed the microscopy results detecting fluorescence only from four tested LysL-sensitive strains but not from 11 tested LysL-resistant strains. Specific binding of HGFPuv_CBDLysL onto the LysL-sensitive cells but not onto the LysL-resistant strains indicates that the C-terminus of LysL contains specific CBD. In conclusion, this report presents experimental evidence of the presence of a CBD in a lactococcal phage lysin. Moreover, the inability of HGFPuv_CBDLysL to bind to the LysL producer LAC460 may partly explain the host's resistance to its own prophage lysin.
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Affiliation(s)
- Samira Mokhtari
- Department of Microbiology, University of Helsinki, P.O. Box 56, 00014, Helsinki, Finland.
| | - Yanru Li
- Department of Microbiology, University of Helsinki, P.O. Box 56, 00014, Helsinki, Finland
| | - Per E J Saris
- Department of Microbiology, University of Helsinki, P.O. Box 56, 00014, Helsinki, Finland
| | - Timo M Takala
- Department of Microbiology, University of Helsinki, P.O. Box 56, 00014, Helsinki, Finland
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3
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Bozidis P, Markou E, Gouni A, Gartzonika K. Does Phage Therapy Need a Pan-Phage? Pathogens 2024; 13:522. [PMID: 38921819 PMCID: PMC11206709 DOI: 10.3390/pathogens13060522] [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: 05/16/2024] [Revised: 06/13/2024] [Accepted: 06/17/2024] [Indexed: 06/27/2024] Open
Abstract
The emergence of multidrug-resistant bacteria is undoubtedly one of the most serious global health threats. One response to this threat that has been gaining momentum over the past decade is 'phage therapy'. According to this, lytic bacteriophages are used for the treatment of bacterial infections, either alone or in combination with antimicrobial agents. However, to ensure the efficacy and broad applicability of phage therapy, several challenges must be overcome. These challenges encompass the development of methods and strategies for the host range manipulation and bypass of the resistance mechanisms developed by pathogenic bacteria, as has been the case since the advent of antibiotics. As our knowledge and understanding of the interactions between phages and their hosts evolves, the key issue is to define the host range for each application. In this article, we discuss the factors that affect host range and how this determines the classification of phages into different categories of action. For each host range group, recent representative examples are provided, together with suggestions on how the different groups can be used to combat certain types of bacterial infections. The available methodologies for host range expansion, either through sequential adaptation to a new pathogen or through genetic engineering techniques, are also reviewed.
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Affiliation(s)
- Petros Bozidis
- Department of Microbiology, Faculty of Medicine, School of Health Sciences, University of Ioannina, 45110 Ioannina, Greece;
- Department of Microbiology, University Hospital of Ioannina, 45500 Ioannina, Greece; (E.M.); (A.G.)
| | - Eleftheria Markou
- Department of Microbiology, University Hospital of Ioannina, 45500 Ioannina, Greece; (E.M.); (A.G.)
| | - Athanasia Gouni
- Department of Microbiology, University Hospital of Ioannina, 45500 Ioannina, Greece; (E.M.); (A.G.)
| | - Konstantina Gartzonika
- Department of Microbiology, Faculty of Medicine, School of Health Sciences, University of Ioannina, 45110 Ioannina, Greece;
- Department of Microbiology, University Hospital of Ioannina, 45500 Ioannina, Greece; (E.M.); (A.G.)
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4
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White K, Eraclio G, McDonnell B, Bottacini F, Lugli GA, Ventura M, Volontè F, Dal Bello F, Mahony J, van Sinderen D. A multifaceted investigation of lactococcal strain diversity in undefined mesophilic starter cultures. Appl Environ Microbiol 2024; 90:e0215223. [PMID: 38334291 PMCID: PMC10952461 DOI: 10.1128/aem.02152-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Accepted: 12/20/2023] [Indexed: 02/10/2024] Open
Abstract
The dairy fermentation industry relies on the activity of lactic acid bacteria in robust starter cultures to accomplish milk acidification. Maintenance of the composition of these starter cultures, whether defined or undefined, is essential to ensure consistent and high-quality fermentation end products. To date, limited information exists regarding the microbial composition of undefined starter culture systems. Here, we describe a culture-based analysis combined with a metagenomics approach to evaluate the composition of two undefined mesophilic starter cultures. In addition, we describe a qPCR-based genotype detection assay, which is capable of discerning nine distinct lactococcal genotypes to characterize these undefined starter cultures, and which can be applied to monitor compositional changes in an undefined starter culture during a fermentation. IMPORTANCE This study reports on the development of a combined culture-based analysis and metagenomics approach to evaluate the composition of two undefined mesophilic starter cultures. In addition, a novel qPCR-based genotype detection assay, capable of discerning nine distinct lactococcal genotypes (based on lactococcal cell wall polysaccharide biosynthesis gene clusters), was used to monitor compositional changes in an undefined starter culture following phage attack. These analytical approaches facilitate a multifaceted assessment of starter culture compositional stability during milk fermentation, which has become an important QC aspect due to the increasing demand for consistent and high-quality dairy products.
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Affiliation(s)
- Kelsey White
- School of Microbiology, University College Cork, Cork, Ireland
- APC Microbiome Ireland, University College Cork, Cork, Ireland
| | | | - Brian McDonnell
- School of Microbiology, University College Cork, Cork, Ireland
- APC Microbiome Ireland, University College Cork, Cork, Ireland
| | - Francesca Bottacini
- APC Microbiome Ireland, University College Cork, Cork, Ireland
- Department of Biological Sciences, Munster Technological University, Cork, Ireland
| | - Gabriele Andrea Lugli
- Department of Chemistry, Life Sciences, and Environmental Sustainability, Laboratory of Probiogenomics,University of Parma, Parma, Italy
| | - Marco Ventura
- Department of Chemistry, Life Sciences, and Environmental Sustainability, Laboratory of Probiogenomics,University of Parma, Parma, Italy
| | | | | | - Jennifer Mahony
- School of Microbiology, University College Cork, Cork, Ireland
- APC Microbiome Ireland, University College Cork, Cork, Ireland
| | - Douwe van Sinderen
- School of Microbiology, University College Cork, Cork, Ireland
- APC Microbiome Ireland, University College Cork, Cork, Ireland
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5
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Guérin H, Courtin P, Guillot A, Péchoux C, Mahony J, van Sinderen D, Kulakauskas S, Cambillau C, Touzé T, Chapot-Chartier MP. Molecular mechanisms underlying the structural diversity of rhamnose-rich cell wall polysaccharides in lactococci. J Biol Chem 2024; 300:105578. [PMID: 38110036 PMCID: PMC10821137 DOI: 10.1016/j.jbc.2023.105578] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Revised: 12/04/2023] [Accepted: 12/11/2023] [Indexed: 12/20/2023] Open
Abstract
In Gram-positive bacteria, cell wall polysaccharides (CWPS) play critical roles in bacterial cell wall homeostasis and bacterial interactions with their immediate surroundings. In lactococci, CWPS consist of two components: a conserved rhamnan embedded in the peptidoglycan layer and a surface-exposed polysaccharide pellicle (PSP), which are linked together to form a large rhamnose-rich CWPS (Rha-CWPS). PSP, whose structure varies from strain to strain, is a receptor for many bacteriophages infecting lactococci. Here, we examined the first two steps of PSP biosynthesis, using in vitro enzymatic tests with lipid acceptor substrates combined with LC-MS analysis, AlfaFold2 modeling of protein 3D-structure, complementation experiments, and phage assays. We show that the PSP repeat unit is assembled on an undecaprenyl-monophosphate (C55P) lipid intermediate. Synthesis is initiated by the WpsA/WpsB complex with GlcNAc-P-C55 synthase activity and the PSP precursor GlcNAc-P-C55 is then elongated by specific glycosyltransferases that vary among lactococcal strains, resulting in PSPs with diverse structures. Also, we engineered the PSP biosynthesis pathway in lactococci to obtain a chimeric PSP structure, confirming the predicted glycosyltransferase specificities. This enabled us to highlight the importance of a single sugar residue of the PSP repeat unit in phage recognition. In conclusion, our results support a novel pathway for PSP biosynthesis on a lipid-monophosphate intermediate as an extracellular modification of rhamnan, unveiling an assembly machinery for complex Rha-CWPS with structural diversity in lactococci.
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Affiliation(s)
- Hugo Guérin
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, Jouy-en-Josas, France
| | - Pascal Courtin
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, Jouy-en-Josas, France
| | - Alain Guillot
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, Jouy-en-Josas, France
| | - Christine Péchoux
- Université Paris-Saclay INRAE, AgroParisTech, GABI, Jouy-en-Josas, France
| | - Jennifer Mahony
- School of Microbiology and APC Microbiome Ireland, University College Cork, Cork, Ireland
| | - Douwe van Sinderen
- School of Microbiology and APC Microbiome Ireland, University College Cork, Cork, Ireland
| | - Saulius Kulakauskas
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, Jouy-en-Josas, France
| | - Christian Cambillau
- School of Microbiology and APC Microbiome Ireland, University College Cork, Cork, Ireland; Laboratoire d'Ingénierie des Systèmes Macromoléculaires (LISM), Institut de Microbiologie, Bioénergies et Biotechnologie (IMM), Aix-Marseille Université - CNRS, UMR 7255, Marseille, France
| | - Thierry Touzé
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
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Giesbers CAP, Fagan J, Parlindungan E, Palussière S, Courtin P, Lugli GA, Ventura M, Kulakauskas S, Chapot-Chartier MP, Mahony J, van Sinderen D. Reduced synthesis of phospho-polysaccharide in Lactococcus as a strategy to evade phage infection. Int J Food Microbiol 2023; 407:110415. [PMID: 37774633 DOI: 10.1016/j.ijfoodmicro.2023.110415] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Revised: 09/18/2023] [Accepted: 09/21/2023] [Indexed: 10/01/2023]
Abstract
Lactococcus spp. are applied routinely in dairy fermentations and their consistent growth and associated acidification activity is critical to ensure the quality and safety of fermented dairy foods. Bacteriophages pose a significant threat to such fermentations and thus it is imperative to study how these bacteria may evade their viral predators in the relevant confined settings. Many lactococcal phages are known to specifically recognise and bind to cell wall polysaccharides (CWPSs) and particularly the phospho-polysaccharide (PSP) side chain component that is exposed on the host cell surface. In the present study, we generated derivatives of a lactococcal strain with reduced phage sensitivity to establish the mode of phage evasion. The resulting mutants were characterized using a combination of comparative genome analysis, microbiological and chemical analyses. Using these approaches, it was established that the phage-resistant derivatives incorporated mutations in genes within the cluster associated with CWPS biosynthesis resulting in growth and morphological defects that could revert when the selective pressure of phages was removed. Furthermore, the cell wall extracts of selected mutants revealed that the phage-resistant strains produced intact PSP but in significantly reduced amounts. The reduced availability of the PSP and the ability of lactococcal strains to revert rapidly to wild type growth and activity in the absence of phage pressure provides Lactococcus with the means to survive and evade phage attack.
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Affiliation(s)
- Conradus A P Giesbers
- School of Microbiology & APC Microbiome Ireland, University College Cork, Western Road, Cork T12 YT20, Ireland.
| | - Jack Fagan
- School of Microbiology & APC Microbiome Ireland, University College Cork, Western Road, Cork T12 YT20, Ireland.
| | - Elvina Parlindungan
- School of Microbiology & APC Microbiome Ireland, University College Cork, Western Road, Cork T12 YT20, Ireland.
| | - Simon Palussière
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, 78350 Jouy-en-Josas, France.
| | - Pascal Courtin
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, 78350 Jouy-en-Josas, France.
| | - Gabriele A Lugli
- Laboratory of Probiogenomics, Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parma, Italy.
| | - Marco Ventura
- Laboratory of Probiogenomics, Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parma, Italy.
| | - Saulius Kulakauskas
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, 78350 Jouy-en-Josas, France.
| | | | - Jennifer Mahony
- School of Microbiology & APC Microbiome Ireland, University College Cork, Western Road, Cork T12 YT20, Ireland.
| | - Douwe van Sinderen
- School of Microbiology & APC Microbiome Ireland, University College Cork, Western Road, Cork T12 YT20, Ireland.
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7
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Mahony J, Goulet A, van Sinderen D, Cambillau C. Partial Atomic Model of the Tailed Lactococcal Phage TP901-1 as Predicted by AlphaFold2: Revelations and Limitations. Viruses 2023; 15:2440. [PMID: 38140681 PMCID: PMC10747895 DOI: 10.3390/v15122440] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Revised: 12/08/2023] [Accepted: 12/12/2023] [Indexed: 12/24/2023] Open
Abstract
Bacteria are engaged in a constant battle against preying viruses, called bacteriophages (or phages). These remarkable nano-machines pack and store their genomes in a capsid and inject it into the cytoplasm of their bacterial prey following specific adhesion to the host cell surface. Tailed phages possessing dsDNA genomes are the most abundant phages in the bacterial virosphere, particularly those with long, non-contractile tails. All tailed phages possess a nano-device at their tail tip that specifically recognizes and adheres to a suitable host cell surface receptor, being proteinaceous and/or saccharidic. Adhesion devices of tailed phages infecting Gram-positive bacteria are highly diverse and, for the majority, remain poorly understood. Their long, flexible, multi-domain-encompassing tail limits experimental approaches to determine their complete structure. We have previously shown that the recently developed protein structure prediction program AlphaFold2 can overcome this limitation by predicting the structures of phage adhesion devices with confidence. Here, we extend this approach and employ AlphaFold2 to determine the structure of a complete phage, the lactococcal P335 phage TP901-1. Herein we report the structures of its capsid and neck, its extended tail, and the complete adhesion device, the baseplate, which was previously partially determined using X-ray crystallography.
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Affiliation(s)
- Jennifer Mahony
- School of Microbiology & APC Microbiome Ireland, University College Cork, T12 K8AF Cork, Ireland;
| | - Adeline Goulet
- Laboratoire d’Ingénierie des Systèmes Macromoléculaires (LISM), Institut de Microbiologie, Bioénergies et Biotechnologie (IMM), Aix-Marseille Université—CNRS, UMR 7255, 13009 Marseille, France;
| | - Douwe van Sinderen
- School of Microbiology & APC Microbiome Ireland, University College Cork, T12 K8AF Cork, Ireland;
| | - Christian Cambillau
- School of Microbiology & APC Microbiome Ireland, University College Cork, T12 K8AF Cork, Ireland;
- Laboratoire d’Ingénierie des Systèmes Macromoléculaires (LISM), Institut de Microbiologie, Bioénergies et Biotechnologie (IMM), Aix-Marseille Université—CNRS, UMR 7255, 13009 Marseille, France;
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8
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Seiler J, Millen A, Romero DA, Magill D, Simdon L. Novel P335-like Phage Resistance Arises from Deletion within Putative Autolysin yccB in Lactococcus lactis. Viruses 2023; 15:2193. [PMID: 38005870 PMCID: PMC10675428 DOI: 10.3390/v15112193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Revised: 10/18/2023] [Accepted: 10/26/2023] [Indexed: 11/26/2023] Open
Abstract
Lactococcus lactis and Lactococcus cremoris are broadly utilized as starter cultures for fermented dairy products and are inherently impacted by bacteriophage (phage) attacks in the industrial environment. Consequently, the generation of bacteriophage-insensitive mutants (BIMs) is a standard approach for addressing phage susceptibility in dairy starter strains. In this study, we characterized spontaneous BIMs of L. lactis DGCC12699 that gained resistance against homologous P335-like phages. Phage resistance was found to result from mutations in the YjdB domain of yccB, a putative autolysin gene. We further observed that alteration of a fused tail-associated lysin-receptor binding protein (Tal-RBP) in the phage restored infectivity on the yccB BIMs. Additional investigation found yccB homologs to be widespread in L. lactis and L. cremoris and that different yccB homologs are highly correlated with cell wall polysaccharide (CWPS) type/subtype. CWPS are known lactococcal phage receptors, and we found that truncation of a glycosyltransferase in the cwps operon also resulted in resistance to these P335-like phages. However, characterization of the CWPS mutant identified notable differences from the yccB mutants, suggesting the two resistance mechanisms are distinct. As phage resistance correlated with yccB mutation has not been previously described in L. lactis, this study offers insight into a novel gene involved in lactococcal phage sensitivity.
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Affiliation(s)
- Jenny Seiler
- IFF, Madison, WI 53716, USA; (A.M.); (D.A.R.); (L.S.)
| | - Anne Millen
- IFF, Madison, WI 53716, USA; (A.M.); (D.A.R.); (L.S.)
| | | | | | - Laura Simdon
- IFF, Madison, WI 53716, USA; (A.M.); (D.A.R.); (L.S.)
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9
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Millen AM, Magill D, Romero D, Simdon L. Evolved distal tail protein of skunaviruses facilitates adsorption to exopolysaccharide-encoding lactococci. MICROBIOME RESEARCH REPORTS 2023; 2:26. [PMID: 38045920 PMCID: PMC10688798 DOI: 10.20517/mrr.2023.29] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 06/10/2023] [Accepted: 06/29/2023] [Indexed: 12/05/2023]
Abstract
Aim: Lactococcal skunaviruses are diverse and problematic in the industrial dairy environment. Host recognition involves the specific interaction of phage-encoded proteins with saccharidic host cell surface structures. Lactococcal plasmid pEPS6073 encodes genes required for the biosynthesis of a cell surface-associated exopolysaccharide (EPS), designated 6073-like. Here, the impact of this EPS on Skunavirus sensitivity was assessed. Methods: Conjugal transfer of pEPS6073 into two model strains followed by phage plaque assays and adsorption assays were performed to assess its effect on phage sensitivity. Phage distal tail proteins were analyzed bioinformatically using HHpred and modeling with AlphaFold. Construction of recombinant phages carrying evolved Dits was performed by supplying a plasmid-encoded template for homologous recombination. Results: pEPS6073 confers resistance against a subset of skunaviruses via adsorption inhibition. IFF collection skunaviruses that infect strains encoding the 6073-like eps gene cluster carry insertions in their distal tail protein-encoding (dit) genes that result in longer Dit proteins (so-called evolved Dits), which encode carbohydrate-binding domains. Three skunaviruses with classical Dits (no insertion) were unable to fully infect their hosts following the conjugal introduction of pEPS6073, showing reductions in both adsorption and efficiency of plaquing. Cloning the evolved Dit into these phages enabled full infectivity on their host strains, both wild type and transconjugant carrying pEPS6073, with recombinant phages adsorbing slightly better to the EPS+ host than wild type. Conclusion: The 6073-like EPS potentially occludes the phage receptor for skunaviruses that encode a classical Dit protein. Skunaviruses that infect strains encoding the 6073-like EPS harbor evolved Dits, which likely help promote phage adsorption rather than just allow the phage to circumvent the putative EPS barrier. This work furthers our knowledge of phage-host interactions in Lactococcus and proposes a role for insertions in the Dit proteins of a subset of skunaviruses.
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Affiliation(s)
| | - Damian Magill
- Health and Biosciences, IFF, Dangé-Saint-Romain 86220, France
| | | | - Laura Simdon
- Health and Biosciences, IFF, Madison, WI 53716, USA
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10
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Takala TM, Mokhtari S, Ahonen SL, Wan X, Saris PEJ. Wild-type Lactococcus lactis producing bacteriocin-like prophage lysins. Front Microbiol 2023; 14:1219723. [PMID: 37520360 PMCID: PMC10377672 DOI: 10.3389/fmicb.2023.1219723] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Accepted: 06/26/2023] [Indexed: 08/01/2023] Open
Abstract
Introduction Lactococcus is a genus of lactic acid bacteria used in the dairy industry as a starter. Lactococci have been found to produce altogether more than 40 different bacteriocins, ribosomally synthesized antimicrobial proteins. All known Lactococcus spp. bacteriocins belong to classes I and II, which are mainly heat-resistant peptides. No class III bacteriocins, bigger heat-sensitive proteins, including phage tail-like bacteriocins, have been found from the Lactococcus spp. Unlike phage tail-like bacteriocins, prophage lysins have not been regarded as bacteriocins, possibly because phage lysins contribute to autolysis, degrading the host's own cell wall. Methods Wild-type Lactococcus lactis strain LAC460, isolated from spontaneously fermented idli batter, was examined for its antimicrobial activity. We sequenced the genome, searched phage lysins from the culture supernatant, and created knock-out mutants to find out the source of the antimicrobial activity. Results and discussion The strain LAC460 was shown to kill other Lactococcus strains with protease- and heat-sensitive lytic activity. Three phage lysins were identified in the culture supernatant. The genes encoding the three lysins were localized in different prophage regions in the chromosome. By knock-out mutants, two of the lysins, namely LysL and LysP, were demonstrated to be responsible for the antimicrobial activity. The strain LAC460 was found to be resistant to the lytic action of its own culture supernatant, and as a consequence, the phage lysins could behave like bacteriocins targeting and killing other closely related bacteria. Hence, similar to phage tail-like bacteriocins, phage lysin-like bacteriocins could be regarded as a novel type of class III bacteriocins.
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Affiliation(s)
- Timo M. Takala
- Department of Microbiology, Faculty of Agriculture and Forestry, University of Helsinki, Helsinki, Finland
| | - Samira Mokhtari
- Department of Microbiology, Faculty of Agriculture and Forestry, University of Helsinki, Helsinki, Finland
| | - Susanna L. Ahonen
- Department of Microbiology, Faculty of Agriculture and Forestry, University of Helsinki, Helsinki, Finland
- Expert Microbiology Unit, Finnish Institute for Health and Welfare, Helsinki, Finland
| | - Xing Wan
- Department of Microbiology, Faculty of Agriculture and Forestry, University of Helsinki, Helsinki, Finland
| | - Per E. J. Saris
- Department of Microbiology, Faculty of Agriculture and Forestry, University of Helsinki, Helsinki, Finland
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11
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Ruiz-Cruz S, Sadovskaya I, Mahony J, Grard T, Chapot-Chartier MP, van Sinderen D, Vinogradov E. Structural studies of the deacylated glycolipids and lipoteichoic acid of Lactococcus cremoris 3107. Carbohydr Res 2023; 531:108898. [PMID: 37453325 DOI: 10.1016/j.carres.2023.108898] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Revised: 07/05/2023] [Accepted: 07/10/2023] [Indexed: 07/18/2023]
Abstract
Lactococcus cremoris and Lactococcus lactis are among the most extensively exploited species of lactic acid bacteria in dairy fermentations. The cell wall of lactococci, like other Gram-positive bacteria, possesses a thick peptidoglycan layer, which may incorporate cell wall polysaccharides (CWPS), wall teichoic acids (WTA), and/or lipoteichoic acids (LTA). In this study, we report the isolation, purification and structural analysis of the carbohydrate moieties of glycolipids (GL) and LTA of the L. cremoris model strain 3107. Chemical structures of these compounds were studied by chemical methods, NMR spectroscopy and positive and negative mode ESI MS. We found that the LTA of strain 3107 is composed of short chains of 1,3-polyglycerol phosphate (PGP), attached to O-6 of the non-reducing glucose of the kojibiose-Gro backbone of the glycolipid anchor. Extraction of cells with cold TCA afforded the detection of 1,3-glycerol phosphate chains randomly substituted at O-2 of glycerol by D-Ala. Unlike the LTA of L. lactis strains studied to date, the PGP backbone of the LTA of L. cremoris 3107 did not carry any glycosyl substitution. The deacylated glycolipid fraction contained the free kojibiose-Gro oligosaccharide, identical to the backbone of the GL anchor of LTA, and its shorter fragment α-Glc-1-Gro. These OS may have originated from the GL precursors of LTA biosynthesis.
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Affiliation(s)
- Sofía Ruiz-Cruz
- School of Microbiology and APC Microbiome Ireland, University College Cork, Cork, T12 YT20, Ireland
| | - Irina Sadovskaya
- Univ. Littoral Côte d'Opale, UMRt 1158 BioEcoAgro, USC ANSES, INRAe, Univ. Artois, Univ. Lille, Univ. Picardie Jules Verne, Univ. Liège, Junia, F-62200, Boulogne-sur-Mer, France
| | - Jennifer Mahony
- School of Microbiology and APC Microbiome Ireland, University College Cork, Cork, T12 YT20, Ireland
| | - Thierry Grard
- Univ. Littoral Côte d'Opale, UMRt 1158 BioEcoAgro, USC ANSES, INRAe, Univ. Artois, Univ. Lille, Univ. Picardie Jules Verne, Univ. Liège, Junia, F-62200, Boulogne-sur-Mer, France
| | | | - Douwe van Sinderen
- School of Microbiology and APC Microbiome Ireland, University College Cork, Cork, T12 YT20, Ireland
| | - Evguenii Vinogradov
- National Research Council Canada, 100 Sussex Dr, Ottawa, ON, K1A 0R6, Canada.
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12
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Guérin H, Quénée P, Palussière S, Courtin P, André G, Péchoux C, Costache V, Mahony J, van Sinderen D, Kulakauskas S, Chapot-Chartier MP. PBP2b Mutations Improve the Growth of Phage-Resistant Lactococcus cremoris Lacking Polysaccharide Pellicle. Appl Environ Microbiol 2023; 89:e0210322. [PMID: 37222606 PMCID: PMC10304956 DOI: 10.1128/aem.02103-22] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Accepted: 05/01/2023] [Indexed: 05/25/2023] Open
Abstract
Lactococcus lactis and Lactococcus cremoris are Gram-positive lactic acid bacteria widely used as starter in milk fermentations. Lactococcal cells are covered with a polysaccharide pellicle (PSP) that was previously shown to act as the receptor for numerous bacteriophages of the Caudoviricetes class. Thus, mutant strains lacking PSP are phage resistant. However, because PSP is a key cell wall component, PSP-negative mutants exhibit dramatic alterations of cell shape and severe growth defects, which limit their technological value. In the present study, we isolated spontaneous mutants with improved growth, from L. cremoris PSP-negative mutants. These mutants grow at rates similar to the wild-type strain, and based on transmission electron microscopy analysis, they exhibit improved cell morphology compared to their parental PSP-negative mutants. In addition, the selected mutants maintain their phage resistance. Whole-genome sequencing of several such mutants showed that they carried a mutation in pbp2b, a gene encoding a penicillin-binding protein involved in peptidoglycan biosynthesis. Our results indicate that lowering or turning off PBP2b activity suppresses the requirement for PSP and ameliorates substantially bacterial fitness and morphology. IMPORTANCE Lactococcus lactis and Lactococcus cremoris are widely used in the dairy industry as a starter culture. As such, they are consistently challenged by bacteriophage infections which may result in reduced or failed milk acidification with associated economic losses. Bacteriophage infection starts with the recognition of a receptor at the cell surface, which was shown to be a cell wall polysaccharide (the polysaccharide pellicle [PSP]) for the majority of lactococcal phages. Lactococcal mutants devoid of PSP exhibit phage resistance but also reduced fitness, since their morphology and division are severely impaired. Here, we isolated spontaneous, food-grade non-PSP-producing L. cremoris mutants resistant to bacteriophage infection with a restored fitness. This study provides an approach to isolate non-GMO phage-resistant L. cremoris and L. lactis strains, which can be applied to strains with technological functionalities. Also, our results highlight for the first time the link between peptidoglycan and cell wall polysaccharide biosynthesis.
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Affiliation(s)
- Hugo Guérin
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, Jouy-en-Josas, France
| | - Pascal Quénée
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, Jouy-en-Josas, France
| | - Simon Palussière
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, Jouy-en-Josas, France
| | - Pascal Courtin
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, Jouy-en-Josas, France
| | - Gwenaëlle André
- Université Paris-Saclay, INRAE, MaIAGE, Jouy-en-Josas, France
| | - Christine Péchoux
- Université Paris-Saclay, INRAE, GABI, Jouy-en-Josas, France
- MIMA2 Imaging Core Facility, Microscopie et Imagerie des Microorganismes, Animaux et Aliments, INRAE, Jouy-en-Josas, France
| | - Vlad Costache
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, Jouy-en-Josas, France
- MIMA2 Imaging Core Facility, Microscopie et Imagerie des Microorganismes, Animaux et Aliments, INRAE, Jouy-en-Josas, France
| | - Jennifer Mahony
- School of Microbiology and APC Microbiome Ireland, University College Cork, Cork, Ireland
| | - Douwe van Sinderen
- School of Microbiology and APC Microbiome Ireland, University College Cork, Cork, Ireland
| | - Saulius Kulakauskas
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, Jouy-en-Josas, France
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13
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Wakinaka T, Matsutani M, Watanabe J, Mogi Y, Tokuoka M, Ohnishi A. Identification of Capsular Polysaccharide Synthesis Loci Determining Bacteriophage Susceptibility in Tetragenococcus halophilus. Microbiol Spectr 2023; 11:e0038523. [PMID: 37154759 PMCID: PMC10269466 DOI: 10.1128/spectrum.00385-23] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Accepted: 04/17/2023] [Indexed: 05/10/2023] Open
Abstract
Bacteriophages infecting Tetragenococcus halophilus, a halophilic lactic acid bacterium, have been a major industrial concern due to their detrimental effects on the quality of food products. Previously characterized tetragenococcal phages displayed narrow host ranges, but there is little information on these mechanisms. Here, we revealed the host's determinant factors for phage susceptibility using two virulent phages, phiYA5_2 and phiYG2_4, that infect T. halophilus YA5 and YG2, respectively. Phage-resistant derivatives were obtained from these host strains, and mutations were found at the capsular polysaccharide (CPS) synthesis (cps) loci. Quantification analysis verified that capsular polysaccharide production by the cps derivatives from YG2 was impaired. Transmission electron microscopy observation confirmed the presence of filamentous structures outside the cell walls of YG2 and their absence in the cps derivatives of YG2. Phage adsorption assays revealed that phiYG2_4 adsorbed to YG2 but not its cps derivatives, which suggests that the capsular polysaccharide of YG2 is the specific receptor for phiYG2_4. Interestingly, phiYA5_2 adsorbed and infected cps derivatives of YG2, although neither adsorption to nor infection of the parental strain YG2 by phiYA5_2 was observed. The plaque-surrounding halos formed by phiYA5_2 implied the presence of the virion-associated depolymerase that degrades the capsular polysaccharide of YA5. These results indicated that the capsular polysaccharide is a physical barrier rather than a binding receptor for phiYA5_2 and that phiYA5_2 specifically overcomes the capsular polysaccharide of YA5. Thus, it is suggested that tetragenococcal phages utilize CPSs as binding receptors and/or degrade CPSs to approach host cells. IMPORTANCE T. halophilus is a halophilic lactic acid bacterium that contributes to the fermentation processes for various salted foods. Bacteriophage infections of T. halophilus have been a major industrial problem causing fermentation failures. Here, we identified the cps loci in T. halophilus as genetic determinants of phage susceptibility. The structural diversity of the capsular polysaccharide is responsible for the narrow host ranges of tetragenococcal phages. The information provided here could facilitate future studies on tetragenococcal phages and the development of efficient methods to prevent bacteriophage infections.
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Affiliation(s)
| | | | - Jun Watanabe
- Manufacturing Division, Yamasa Corporation, Choshi, Japan
- Faculty of Food and Agricultural Sciences, Fukushima University, Fukushima, Japan
- Institute of Fermentation Sciences, Fukushima University, Fukushima, Japan
| | - Yoshinobu Mogi
- Manufacturing Division, Yamasa Corporation, Choshi, Japan
| | - Masafumi Tokuoka
- Department of Fermentation Science, Faculty of Applied Biosciences, Tokyo University of Agriculture, Tokyo, Japan
| | - Akihiro Ohnishi
- Department of Fermentation Science, Faculty of Applied Biosciences, Tokyo University of Agriculture, Tokyo, Japan
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14
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Cambillau C, Goulet A. Exploring Host-Binding Machineries of Mycobacteriophages with AlphaFold2. J Virol 2023; 97:e0179322. [PMID: 36916948 PMCID: PMC10062164 DOI: 10.1128/jvi.01793-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Accepted: 02/17/2023] [Indexed: 03/16/2023] Open
Abstract
Although more than 12,000 bacteriophages infecting mycobacteria (mycobacteriophages) have been isolated so far, there is a knowledge gap on their structure-function relationships. Here, we have explored the architecture of host-binding machineries from seven representative mycobacteriophages of the Siphoviridae family infecting Mycobacterium smegmatis, Mycobacterium abscessus, and Mycobacterium tuberculosis, using AlphaFold2 (AF2). AF2 enables confident structural analyses of large and flexible biological assemblies resistant to experimental methods, thereby opening new avenues to shed light on phage structure and function. Our results highlight the modularity and structural diversity of siphophage host-binding machineries that recognize host-specific receptors at the onset of viral infection. Interestingly, the studied mycobacteriophages' host-binding machineries present unique features compared with those of phages infecting other Gram-positive actinobacteria. Although they all assemble the classical Dit (distal tail), Tal (tail-associated lysin), and receptor-binding proteins, five of them contain two potential additional adhesion proteins. Moreover, we have identified brush-like domains formed of multiple polyglycine helices which expose hydrophobic residues as potential receptor-binding domains. These polyglycine-rich domains, which have been observed in only five native proteins, may be a hallmark of mycobacteriophages' host-binding machineries, and they may be more common in nature than expected. Altogether, the unique composition of mycobacteriophages' host-binding machineries indicate they might have evolved to bind to the peculiar mycobacterial cell envelope, which is rich in polysaccharides and mycolic acids. This work provides a rational framework to efficiently produce recombinant proteins or protein domains and test their host-binding function and, hence, to shed light on molecular mechanisms used by mycobacteriophages to infect their host. IMPORTANCE Mycobacteria include both saprophytes, such as the model system Mycobacterium smegmatis, and pathogens, such as Mycobacterium tuberculosis and Mycobacterium abscessus, that are poorly responsive to antibiotic treatments and pose a global public health problem. Mycobacteriophages have been collected at a very large scale over the last decade, and they have proven to be valuable tools for mycobacteria genetic manipulation, rapid diagnostics, and infection treatment. Yet, molecular mechanisms used by mycobacteriophages to infect their host remain poorly understood. Therefore, exploring the structural diversity of mycobacteriophages' host-binding machineries is important not only to better understand viral diversity and bacteriophage-host interactions, but also to rationally develop biotechnological tools. With the powerful protein structure prediction software AlphaFold2, which was publicly released a year ago, it is now possible to gain structural and functional insights on such challenging assemblies.
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Affiliation(s)
- Christian Cambillau
- School of Microbiology, University College Cork, Cork, Ireland
- AlphaGraphix, Formiguères, France
| | - Adeline Goulet
- Laboratoire d’Ingénierie des Systèmes Macromoléculaires, Institut de Microbiologie, Bioénergies et Biotechnologie, CNRS and Aix-Marseille Université, Marseille, France
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15
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Leprince A, Mahillon J. Phage Adsorption to Gram-Positive Bacteria. Viruses 2023; 15:196. [PMID: 36680236 PMCID: PMC9863714 DOI: 10.3390/v15010196] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2022] [Revised: 01/03/2023] [Accepted: 01/06/2023] [Indexed: 01/12/2023] Open
Abstract
The phage life cycle is a multi-stage process initiated by the recognition and attachment of the virus to its bacterial host. This adsorption step depends on the specific interaction between bacterial structures acting as receptors and viral proteins called Receptor Binding Proteins (RBP). The adsorption process is essential as it is the first determinant of phage host range and a sine qua non condition for the subsequent conduct of the life cycle. In phages belonging to the Caudoviricetes class, the capsid is attached to a tail, which is the central player in the adsorption as it comprises the RBP and accessory proteins facilitating phage binding and cell wall penetration prior to genome injection. The nature of the viral proteins involved in host adhesion not only depends on the phage morphology (i.e., myovirus, siphovirus, or podovirus) but also the targeted host. Here, we give an overview of the adsorption process and compile the available information on the type of receptors that can be recognized and the viral proteins taking part in the process, with the primary focus on phages infecting Gram-positive bacteria.
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16
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Bipartite rgp Locus Diversity in Streptococcus thermophilus Corresponds to Backbone and Side Chain Differences of Its Rhamnose-Containing Cell Wall Polysaccharide. Appl Environ Microbiol 2022; 88:e0150422. [PMID: 36350137 PMCID: PMC9746298 DOI: 10.1128/aem.01504-22] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
The rhamnose-glucose polysaccharide (Rgp) of Streptococcus thermophilus represents a major cell wall component, and the gene cluster responsible for its biosynthesis (termed rgp) has recently been identified. Significant genetic diversity among these loci has previously been reported, with five distinct rgp genotypes identified (designated rgp1 through -5). In the present study, two additional genotypes were identified (designated rgp6 and rgp7) through comparative analysis of the rgp loci of 78 Streptococcus thermophilus genomes. The rgp locus of a given S. thermophilus strain encoded the biosynthetic machinery for a rhamnan-rich backbone and a variable side chain component, the latter being associated with the highly specific interactions with many bacteriophages that infect this species. The chemical structure of the Rgp from three S. thermophilus strains, representing the rgp2, -3, and -4 genotypes, was elucidated, and based on bioinformatic and biochemical analyses we propose a model for Rgp biosynthesis in dairy streptococci. Furthermore, we exploited the genetic diversity within the S. thermophilus bipartite rgp locus to develop a two-step multiplex PCR system to classify strains based on gene content associated with the biosynthesis of the variable side chain structure as well as the rhamnan backbone. IMPORTANCE Streptococcus thermophilus is present and applied in industrial and artisanal dairy fermentations for the production of various cheeses and yogurt. During these fermentations, S. thermophilus is vulnerable to phage predation, and recent studies have identified the rhamnose-glucose polymer (Rgp) as the definitive receptor for at least one problematic phage species. Detailed analysis of S. thermophilus rgp loci has revealed an unprecedented level of genetic diversity, particularly within the glycosyltransferase-encoding gene content of a given locus. Our study shows that this genetic diversity reflects the biochemical structure(s) of S. thermophilus Rgp. As such, we harnessed the genetic diversity of S. thermophilus rgp loci to develop a two-step multiplex PCR method for the classification of strain collections and, ultimately, the formation of phage-robust rational starter sets.
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17
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Ruiz‐Cruz S, Erazo Garzon A, Kelleher P, Bottacini F, Breum SØ, Neve H, Heller KJ, Vogensen FK, Palussière S, Courtin P, Chapot‐Chartier M, Vinogradov E, Sadovskaya I, Mahony J, van Sinderen D. Host genetic requirements for DNA release of lactococcal phage TP901-1. Microb Biotechnol 2022; 15:2875-2889. [PMID: 36259418 PMCID: PMC9733650 DOI: 10.1111/1751-7915.14156] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Revised: 08/29/2022] [Accepted: 09/27/2022] [Indexed: 12/14/2022] Open
Abstract
The first step in phage infection is the recognition of, and adsorption to, a receptor located on the host cell surface. This reversible host adsorption step is commonly followed by an irreversible event, which involves phage DNA delivery or release into the bacterial cytoplasm. The molecular components that trigger this latter event are unknown for most phages of Gram-positive bacteria. In the current study, we present a comparative genome analysis of three mutants of Lactococcus cremoris 3107, which are resistant to the P335 group phage TP901-1 due to mutations that affect TP901-1 DNA release. Through genetic complementation and phage infection assays, a predicted lactococcal three-component glycosylation system (TGS) was shown to be required for TP901-1 infection. Major cell wall saccharidic components were analysed, but no differences were found. However, heterologous gene expression experiments indicate that this TGS is involved in the glucosylation of a cell envelope-associated component that triggers TP901-1 DNA release. To date, a saccharide modification has not been implicated in the DNA delivery process of a Gram-positive infecting phage.
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Affiliation(s)
- Sofía Ruiz‐Cruz
- School of Microbiology & APC Microbiome IrelandUniversity College CorkCorkIreland
| | - Andrea Erazo Garzon
- School of Microbiology & APC Microbiome IrelandUniversity College CorkCorkIreland
| | - Philip Kelleher
- School of Microbiology & APC Microbiome IrelandUniversity College CorkCorkIreland
| | - Francesca Bottacini
- School of Microbiology & APC Microbiome IrelandUniversity College CorkCorkIreland,Department of Biological SciencesMunster Technological UniversityCorkIreland
| | - Solvej Østergaard Breum
- Section of Microbiology and Fermentation, Department of Food Science, Faculty of ScienceUniversity of CopenhagenFrederiksbergDenmark,Present address:
Department of Virus & Microbiological Special Diagnostics, Division of Infectious Disease Preparedness, Statens Serum InstitutCopenhagenDenmark
| | - Horst Neve
- Department of Microbiology and Biotechnology, Max Rubner‐InstitutFederal Research Institute of Nutrition and FoodKielGermany
| | - Knut J. Heller
- Department of Microbiology and Biotechnology, Max Rubner‐InstitutFederal Research Institute of Nutrition and FoodKielGermany
| | - Finn K. Vogensen
- Section of Microbiology and Fermentation, Department of Food Science, Faculty of ScienceUniversity of CopenhagenFrederiksbergDenmark
| | - Simon Palussière
- Université Paris‐Saclay, INRAE, AgroParisTech, Micalis InstituteJouy‐en‐JosasFrance
| | - Pascal Courtin
- Université Paris‐Saclay, INRAE, AgroParisTech, Micalis InstituteJouy‐en‐JosasFrance
| | | | - Evgeny Vinogradov
- National Research Council CanadaInstitute for Biological SciencesOttawaOntarioCanada
| | - Irina Sadovskaya
- Equipe BPA, Université du Littoral‐Côte d'Opale, Institut Charles Violette EA 7394 USC AnsesBoulogne‐sur‐merFrance
| | - Jennifer Mahony
- School of Microbiology & APC Microbiome IrelandUniversity College CorkCorkIreland
| | - Douwe van Sinderen
- School of Microbiology & APC Microbiome IrelandUniversity College CorkCorkIreland
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18
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Millen AM, Romero DA, Horvath P, Magill D, Simdon L. Host-encoded, cell surface-associated exopolysaccharide required for adsorption and infection by lactococcal P335 phage subtypes. Front Microbiol 2022; 13:971166. [PMID: 36267184 PMCID: PMC9576995 DOI: 10.3389/fmicb.2022.971166] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Accepted: 08/19/2022] [Indexed: 11/13/2022] Open
Abstract
Lactococcus lactis and Lactococcus cremoris compose commercial starter cultures widely used for industrial dairy fermentations. Some lactococcal strains may produce exopolysaccharides (EPS), which have technological applications, including texture production and phage resistance. Two distinct gene clusters associated with EPS production, designated 6073-like and 7127-like, were identified on plasmids in lactococcal strains. Infectivity of two subsets of P335 group phages, distinguished based on their single-component baseplate/receptor-binding protein nucleotide sequences, was correlated to the presence of a host-encoded 6073-like or 7127-like eps gene cluster. Furthermore, phages belonging to these subsets differentially adsorbed to lactococcal strains harboring the respective eps gene cluster. Loss of the respective EPS-encoding plasmid from a fully phage-sensitive strain resulted in loss of phage adsorption and resistance to the phage. Transmission electron microscopy (TEM) showed that the EPS produced by strains encoding the 6073-like or 7127-like eps gene clusters are cell-surface associated, which, coupled with phage plaquing and adsorption data, shows that specific capsular EPS are involved in host recognition by certain P335 phage subgroups. To our knowledge, this is the first description of the involvement of EPS produced via the Wzx/Wzy-dependent pathway in phage sensitivity of L. lactis or L. cremoris. This study also shows strains that do not appear to be phage-related based on plaque formation may still be related by phage adsorption and indicates that optimal formulation of phage-robust cultures should take into account the EPS type of individual strains.
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Affiliation(s)
- Anne M. Millen
- Health and Biosciences, IFF, Madison, WI, United States
- *Correspondence: Anne M. Millen,
| | | | | | - Damian Magill
- Health and Biosciences, IFF, Dangé-Saint-Romain, France
| | - Laura Simdon
- Health and Biosciences, IFF, Madison, WI, United States
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19
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Guérin H, Kulakauskas S, Chapot-Chartier MP. Structural variations and roles of rhamnose-rich cell wall polysaccharides in Gram-positive bacteria. J Biol Chem 2022; 298:102488. [PMID: 36113580 PMCID: PMC9574508 DOI: 10.1016/j.jbc.2022.102488] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 09/08/2022] [Accepted: 09/10/2022] [Indexed: 11/17/2022] Open
Abstract
Rhamnose-rich cell wall polysaccharides (Rha-CWPSs) have emerged as crucial cell wall components of numerous Gram-positive, ovoid-shaped bacteria—including streptococci, enterococci, and lactococci—of which many are of clinical or biotechnological importance. Rha-CWPS are composed of a conserved polyrhamnose backbone with side-chain substituents of variable size and structure. Because these substituents contain phosphate groups, Rha-CWPS can also be classified as polyanionic glycopolymers, similar to wall teichoic acids, of which they appear to be functional homologs. Recent advances have highlighted the critical role of these side-chain substituents in bacterial cell growth and division, as well as in specific interactions between bacteria and infecting bacteriophages or eukaryotic hosts. Here, we review the current state of knowledge on the structure and biosynthesis of Rha-CWPS in several ovoid-shaped bacterial species. We emphasize the role played by multicomponent transmembrane glycosylation systems in the addition of side-chain substituents of various sizes as extracytoplasmic modifications of the polyrhamnose backbone. We provide an overview of the contribution of Rha-CWPS to cell wall architecture and biogenesis and discuss current hypotheses regarding their importance in the cell division process. Finally, we sum up the critical roles that Rha-CWPS can play as bacteriophage receptors or in escaping host defenses, roles that are mediated mainly through their side-chain substituents. From an applied perspective, increased knowledge of Rha-CWPS can lead to advancements in strategies for preventing phage infection of lactococci and streptococci in food fermentation and for combating pathogenic streptococci and enterococci.
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Affiliation(s)
- Hugo Guérin
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, Jouy-en-Josas, France
| | - Saulius Kulakauskas
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, Jouy-en-Josas, France
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20
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Mizukoshi H, Kimura K, Ikemura H, Mori Y, Nagaoka M. Structural determination of the cell wall polysaccharide LCPS-1 in Lacticaseibacillus paracasei strain Shirota YIT 9029. Carbohydr Res 2022; 521:108670. [PMID: 36103733 DOI: 10.1016/j.carres.2022.108670] [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: 03/24/2022] [Revised: 08/29/2022] [Accepted: 08/30/2022] [Indexed: 11/02/2022]
Abstract
The neutral polysaccharides LCPS-1 and LCPS-2 play functional roles in the cell wall of the lactic acid bacterium Lacticaseibacillus paracasei strain Shirota YIT 9029 (LcS; formerly Lactobacillus casei strain Shirota YIT 9029), which has long been used as a probiotic food product. Studies have shown that LCPS-1 is associated with the immunomodulatory functions of LcS. We hypothesized that the structure of LCPS-1 is crucial for elucidating the mechanism of action of LcS on host immune responses and aimed to solve the undetermined primary structure of LCPS-1. Our results showed that LCPS-1 has a molecular weight of >400 kDa and is composed of Glc, Rha, Gal, and GlcNAc, with a repeating structure. Using limited degradation reactions, including controlled Smith and deamination degradations, we obtained key fragments with low molecular weight. Subsequently, their structures were analyzed using NMR spectra and other analytical techniques. Further, we integrated the results for each key fragment to derive the complete structure of LCPS-1. Our results indicated that the most probable structure of LCPS-1 is composed of two types of units (X, Y), each with a basic structure of seven sugars in which the C2-position of Rha is substituted with an acetyl group. The structure of X is {6[Glcβ1-2] Galα1-3[2-OAc] Rhaβ1-4Glcβ1-4[Rhaα1-3] [Glcα1-6] Glcβ1-} and that of Y is {6[Glcβ1-2] Galα1-3[2-OAc] Rhaβ1-4Glcβ1-4[Rhaα1-3] [Glcα1-6)] GlcNAcβ1-}, which can be expressed as (X6Y12)n. In this study, we identified the primary structure of LCPS-1, and our results may enable an improved understanding of the immunomodulatory abilities of LcS.
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Affiliation(s)
- Harumi Mizukoshi
- Yakult Central Institute for Microbiological Research, 5-11 Izumi Kunitachi-shi, Tokyo, 186-8650, Japan.
| | - Kazumasa Kimura
- Yakult Central Institute for Microbiological Research, 5-11 Izumi Kunitachi-shi, Tokyo, 186-8650, Japan
| | - Haruo Ikemura
- Yakult Central Institute for Microbiological Research, 5-11 Izumi Kunitachi-shi, Tokyo, 186-8650, Japan
| | - Yoko Mori
- Yakult Central Institute for Microbiological Research, 5-11 Izumi Kunitachi-shi, Tokyo, 186-8650, Japan
| | - Masato Nagaoka
- Yakult Central Institute for Microbiological Research, 5-11 Izumi Kunitachi-shi, Tokyo, 186-8650, Japan
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Viral Proteins Involved in the Adsorption Process of Deep-Purple, a Siphovirus Infecting Members of the Bacillus cereus Group. Appl Environ Microbiol 2022; 88:e0247821. [PMID: 35499330 PMCID: PMC9128512 DOI: 10.1128/aem.02478-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The infection of a bacterium by a tailed phage starts from the adsorption process, which consists of a specific and strong interaction between viral proteins called receptor binding proteins (RBPs) and receptors located on the bacterial surface. In addition to RBPs, other tail proteins, such as evolved distal tail (evoDit) proteins and tail lysins, harboring carbohydrate binding modules (CBMs) have been shown to facilitate the phage adsorption by interacting with host polysaccharides. In this work, the proteins involved in the adsorption of Deep-Purple, a siphovirus targeting bacteria of the Bacillus cereus group, were studied. Bioinformatic analysis of Deep-Purple tail protein region revealed that it contains two proteins presenting CBM domains: Gp28, an evoDit protein, and Gp29, the potential RBP. The implication of both proteins in the adsorption of Deep-Purple particles was confirmed through cell wall decoration assays. Interestingly, whereas RBP-Gp29 exhibited the same host spectrum as Deep-Purple, evoDit-Gp28 was able to bind to many B. cereus group strains, including some that are not sensitive to the phage infection. Using immunogold microscopy, both proteins were shown to be located in the phage baseplate. Additionally, an in silico analysis of the tail regions encoded by several Siphoviridae infecting the B. cereus group was performed. It revealed that although the tail organization displayed by Deep-Purple is the most prevalent, different tail arrangements are observed, suggesting that distinct baseplate organization and adsorption mechanisms are encountered in siphoviruses targeting the B. cereus group. IMPORTANCE The B. cereus group is a complex cluster of closely related species, among which certain strains can be pathogenic (i.e., Bacillus anthracis, Bacillus cereussensu stricto, and Bacillus cytotoxicus). Nowadays, phages are receiving increasing attention for applications in controlling and detecting such pathogens. Thus, understanding the molecular mechanisms governing the phage adsorption to its bacterial host is paramount as this step is a key determinant of the phage host spectrum. Until now, the knowledge regarding the adsorption process of tailed phage targeting the B. cereus groups was mainly restricted to the phage gamma infecting B. anthracis. With this work, we provide novel insights into the adsorption of Deep-Purple, a siphovirus infecting the B. cereus group. We showed that this phage recognizes polysaccharides and relies on two different viral proteins for its successful adsorption.
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Abstract
The field of metagenomics has rapidly expanded to become the go-to method for complex microbial community analyses. However, there is currently no straightforward route from metagenomics to traditional culture-based methods of strain isolation, particularly in (bacterio)phage biology, leading to an investigative bottleneck. Here, we describe a method that exploits specific phage receptor binding protein (RBP)-host cell surface receptor interaction enabling isolation of phage-host combinations from an environmental sample. The method was successfully applied to two complex sample types-a dairy-derived whey sample and an infant fecal sample, enabling retrieval of specific and culturable phage hosts. IMPORTANCE PhRACS aims to bridge the current divide between in silico genetic analyses (i.e., phageomic studies) and traditional culture-based methodology. Through the labeling of specific bacterial hosts with fluorescently tagged recombinant phage receptor binding proteins and the isolation of tagged cells using flow cytometry, PhRACS allows the full potential of phageomic data to be realized in the wet laboratory.
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White K, Yu JH, Eraclio G, Dal Bello F, Nauta A, Mahony J, van Sinderen D. Bacteriophage-host interactions as a platform to establish the role of phages in modulating the microbial composition of fermented foods. MICROBIOME RESEARCH REPORTS 2022; 1:3. [PMID: 38089066 PMCID: PMC10714293 DOI: 10.20517/mrr.2021.04] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Revised: 12/23/2021] [Accepted: 12/31/2021] [Indexed: 02/19/2024]
Abstract
Food fermentation relies on the activity of robust starter cultures, which are commonly comprised of lactic acid bacteria such as Lactococcus and Streptococcus thermophilus. While bacteriophage infection represents a persistent threat that may cause slowed or failed fermentations, their beneficial role in fermentations is also being appreciated. In order to develop robust starter cultures, it is important to understand how phages interact with and modulate the compositional landscape of these complex microbial communities. Both culture-dependent and -independent methods have been instrumental in defining individual phage-host interactions of many lactic acid bacteria (LAB). This knowledge needs to be integrated and expanded to obtain a full understanding of the overall complexity of such interactions pertinent to fermented foods through a combination of culturomics, metagenomics, and phageomics. With such knowledge, it is believed that factory-specific detection and monitoring systems may be developed to ensure robust and reliable fermentation practices. In this review, we explore/discuss phage-host interactions of LAB, the role of both virulent and temperate phages on the microbial composition, and the current knowledge of phageomes of fermented foods.
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Affiliation(s)
- Kelsey White
- School of Microbiology & APC Microbiome Ireland, University College Cork, Cork T12 YT20, Ireland
- Authors contributed equally
| | - Jun-Hyeok Yu
- School of Microbiology & APC Microbiome Ireland, University College Cork, Cork T12 YT20, Ireland
- Authors contributed equally
| | | | | | - Arjen Nauta
- FrieslandCampina, Amersfoort 3800 BN, The Netherlands
| | - Jennifer Mahony
- School of Microbiology & APC Microbiome Ireland, University College Cork, Cork T12 YT20, Ireland
| | - Douwe van Sinderen
- School of Microbiology & APC Microbiome Ireland, University College Cork, Cork T12 YT20, Ireland
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Brussowvirus SW13 requires a cell surface-associated polysaccharide to recognise its Streptococcus thermophilus host. Appl Environ Microbiol 2021; 88:e0172321. [PMID: 34669424 PMCID: PMC8752142 DOI: 10.1128/aem.01723-21] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Four bacteriophage-insensitive mutants (BIMs) of the dairy starter bacterium Streptococcus thermophilus UCCSt50 were isolated following challenge with Brussowvirus SW13. The BIMs displayed an altered sedimentation phenotype. Whole-genome sequencing and comparative genomic analysis of the BIMs uncovered mutations within a family 2 glycosyltransferase-encoding gene (orf06955UCCSt50) located within the variable region of the cell wall-associated rhamnose-glucose polymer (Rgp) biosynthesis locus (designated the rgp gene cluster here). Complementation of a representative BIM, S. thermophilus B1, with native orf06955UCCSt50 restored phage sensitivity comparable to that of the parent strain. Detailed bioinformatic analysis of the gene product of orf06955UCCSt50 identified it as a functional homolog of the Lactococcus lactispolysaccharide pellicle (PSP) initiator WpsA. Biochemical analysis of cell wall fractions of strains UCCSt50 and B1 determined that mutations within orf06955UCCSt50 result in the loss of the side chain decoration from the Rgp backbone structure. Furthermore, it was demonstrated that the intact Rgp structure incorporating the side chain structure is essential for phage binding through fluorescence labeling studies. Overall, this study confirms that the rgp gene cluster of S. thermophilus encodes the biosynthetic machinery for a cell surface-associated polysaccharide that is essential for binding and subsequent infection by Brussowviruses, thus enhancing our understanding of S. thermophilus phage-host dynamics. IMPORTANCEStreptococcus thermophilus is an important starter culture bacterium in global dairy fermentation processes, where it is used for the production of various cheeses and yogurt. Bacteriophage predation of the species can result in substandard product quality and, in rare cases, complete fermentation collapse. To mitigate these risks, it is necessary to understand the phage-host interaction process, which commences with the recognition of, and adsorption to, specific host-encoded cell surface receptors by bacteriophage(s). As new groups of S. thermophilus phages are being discovered, the importance of underpinning the genomic elements that specify the surface receptor(s) is apparent. Our research identifies a single gene that is critical for the biosynthesis of a saccharidic moiety required for phage adsorption to its S. thermophilus host. The acquired knowledge provides novel insights into phage-host interactions for this economically important starter species.
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Ramos Y, Sansone S, Morales DK. Sugarcoating it: Enterococcal polysaccharides as key modulators of host-pathogen interactions. PLoS Pathog 2021; 17:e1009822. [PMID: 34499702 PMCID: PMC8428557 DOI: 10.1371/journal.ppat.1009822] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Affiliation(s)
- Yusibeska Ramos
- Department of Obstetrics and Gynecology, Weill Cornell Medicine, New York, New York, United States of America
| | - Stephanie Sansone
- Department of Obstetrics and Gynecology, Weill Cornell Medicine, New York, New York, United States of America
- Department of Urology, Weill Cornell Medicine, New York, New York, United States of America
| | - Diana K. Morales
- Department of Obstetrics and Gynecology, Weill Cornell Medicine, New York, New York, United States of America
- * E-mail:
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26
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Dorau R, Liu J, Solem C, Jensen PR. Metabolic Engineering of Lactic Acid Bacteria. Metab Eng 2021. [DOI: 10.1002/9783527823468.ch15] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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27
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Cell wall polysaccharides of Gram positive ovococcoid bacteria and their role as bacteriophage receptors. Comput Struct Biotechnol J 2021; 19:4018-4031. [PMID: 34377367 PMCID: PMC8327497 DOI: 10.1016/j.csbj.2021.07.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 07/12/2021] [Accepted: 07/12/2021] [Indexed: 11/23/2022] Open
Abstract
Gram-positive bacterial cell walls are characterised by the presence of a thick peptidoglycan layer which provides protection from extracellular stresses, maintains cell integrity and determines cell morphology, while it also serves as a foundation to anchor a number of crucial polymeric structures. For ovococcal species, including streptococci, enterococci and lactococci, such structures are represented by rhamnose-containing cell wall polysaccharides, which at least in some instances appear to serve as a functional replacement for wall teichoic acids. The biochemical composition of several streptococcal, lactococcal and enterococcal rhamnose-containing cell wall polysaccharides have been elucidated, while associated functional genomic analyses have facilitated the proposition of models for individual biosynthetic pathways. Here, we review the genomic loci which encode the enzymatic machinery to produce rhamnose-containing, cell wall-associated polysaccharide (Rha cwps) structures of the afore-mentioned ovococcal bacteria with particular emphasis on gene content, biochemical structure and common biosynthetic steps. Furthermore, we discuss the role played by these saccharidic polymers as receptors for bacteriophages and the important role phages play in driving Rha cwps diversification and evolution.
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28
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Ortiz Charneco G, Kelleher P, Buivydas A, Streekstra H, van Themaat EVL, de Waal PP, Mahony J, van Sinderen D. Genetic Dissection of a Prevalent Plasmid-Encoded Conjugation System in Lactococcus lactis. Front Microbiol 2021; 12:680920. [PMID: 34122391 PMCID: PMC8194271 DOI: 10.3389/fmicb.2021.680920] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Accepted: 04/20/2021] [Indexed: 01/02/2023] Open
Abstract
Plasmid pNP40, which was first identified nearly 40 years ago in Lactococcus lactis subsp. lactis biovar diacetylactis DRC3, encodes functions such as heavy metal-, bacteriophage-, and nisin-resistance, as well as plasmid transfer ability by conjugation. Here, we report an optimized conjugation protocol for this plasmid, yielding a transfer frequency that is approximately 4,000-fold higher than those previously reported in literature, while we also observed high-frequency plasmid co-mobilization. Individual mutations in 18 genes that encompass the presumed conjugation cluster of pNP40 were generated using ssDNA recombineering to evaluate the role of each gene in the conjugation process. A possible transcriptional repressor of this conjugation cluster, the product of the traR gene, was identified in this manner. This mutational analysis, paired with bioinformatic predictions as based on sequence and structural similarities, allowed us to generate a preliminary model of the pNP40 conjugation machinery.
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Affiliation(s)
| | - Philip Kelleher
- School of Microbiology and APC Microbiome Ireland, University College Cork, Cork, Ireland
| | - Andrius Buivydas
- School of Microbiology and APC Microbiome Ireland, University College Cork, Cork, Ireland
| | | | | | | | - Jennifer Mahony
- School of Microbiology and APC Microbiome Ireland, University College Cork, Cork, Ireland
| | - Douwe van Sinderen
- School of Microbiology and APC Microbiome Ireland, University College Cork, Cork, Ireland
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29
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Lee S, Park JH. Characteristics on host specificity, infection, and temperature stability of Weissella phages from watery kimchi. Food Sci Biotechnol 2021; 30:843-851. [PMID: 34249390 DOI: 10.1007/s10068-021-00920-0] [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: 01/27/2021] [Revised: 03/30/2021] [Accepted: 05/14/2021] [Indexed: 10/21/2022] Open
Abstract
Three bacteriophages (phage), ΦWC53, ΦWC54, and ΦWC56, of Weissella were isolated from watery kimchi and characterized. ΦWC53 belonged to Siphoviridae and ΦWC54 and ΦWC56 belonged to Myoviridae family. By one-step growth, the burst sizes were 5-260 particles/infected cells and the latent periods were 20-45 min. The phages infected Weissella spp., Leuconostoc mesenteroides, and Lactobacillus spp., differently by showing clear or turbid plaques. The phage adsorption rates on lactic acid bacteria were high on Weissella and low on Leuconostoc and Lactobacillus. However, the adsorption of ΦWC53 occurred variously among Weissella spp. and Weissella host grew well in the liquid culture without lysis after challenging by ΦWC53. Tolerances of these phages to temperature showed more various than those to pH. ΦWC53 was stable at 7 °C and 30 °C, but ΦWC54 and ΦWC56 were stable only at 7 °C. Therefore, three Weissella phages belonged to the different families and indicated diverse infection patterns on Weissella, Leuconostoc, and Lactobacillus with various stabilities for pH and temperature.
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Affiliation(s)
- Soomin Lee
- Department of Food Science and Biotechnology, Gachon University, Seongnamdae-ro, 13120 Republic of Korea
| | - Jong-Hyun Park
- Department of Food Science and Biotechnology, Gachon University, Seongnamdae-ro, 13120 Republic of Korea
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30
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Martínez B, Rodríguez A, Kulakauskas S, Chapot-Chartier MP. Cell wall homeostasis in lactic acid bacteria: threats and defences. FEMS Microbiol Rev 2021; 44:538-564. [PMID: 32495833 PMCID: PMC7476776 DOI: 10.1093/femsre/fuaa021] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Accepted: 06/03/2020] [Indexed: 12/16/2022] Open
Abstract
Lactic acid bacteria (LAB) encompasses industrially relevant bacteria involved in food fermentations as well as health-promoting members of our autochthonous microbiota. In the last years, we have witnessed major progresses in the knowledge of the biology of their cell wall, the outermost macrostructure of a Gram-positive cell, which is crucial for survival. Sophisticated biochemical analyses combined with mutation strategies have been applied to unravel biosynthetic routes that sustain the inter- and intra-species cell wall diversity within LAB. Interplay with global cell metabolism has been deciphered that improved our fundamental understanding of the plasticity of the cell wall during growth. The cell wall is also decisive for the antimicrobial activity of many bacteriocins, for bacteriophage infection and for the interactions with the external environment. Therefore, genetic circuits involved in monitoring cell wall damage have been described in LAB, together with a plethora of defence mechanisms that help them to cope with external threats and adapt to harsh conditions. Since the cell wall plays a pivotal role in several technological and health-promoting traits of LAB, we anticipate that this knowledge will pave the way for the future development and extended applications of LAB.
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Affiliation(s)
- Beatriz Martínez
- DairySafe research group. Department of Technology and Biotechnology of Dairy Products. Instituto de Productos Lácteos de Asturias, IPLA-CSIC. Paseo Río Linares s/n. 33300 Villaviciosa, Spain
| | - Ana Rodríguez
- DairySafe research group. Department of Technology and Biotechnology of Dairy Products. Instituto de Productos Lácteos de Asturias, IPLA-CSIC. Paseo Río Linares s/n. 33300 Villaviciosa, Spain
| | - Saulius Kulakauskas
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, 78350, Jouy-en-Josas, France
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31
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Romero DA, Magill D, Millen A, Horvath P, Fremaux C. Dairy lactococcal and streptococcal phage-host interactions: an industrial perspective in an evolving phage landscape. FEMS Microbiol Rev 2021; 44:909-932. [PMID: 33016324 DOI: 10.1093/femsre/fuaa048] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Accepted: 09/18/2020] [Indexed: 12/14/2022] Open
Abstract
Almost a century has elapsed since the discovery of bacteriophages (phages), and 85 years have passed since the emergence of evidence that phages can infect starter cultures, thereby impacting dairy fermentations. Soon afterward, research efforts were undertaken to investigate phage interactions regarding starter strains. Investigations into phage biology and morphology and phage-host relationships have been aimed at mitigating the negative impact phages have on the fermented dairy industry. From the viewpoint of a supplier of dairy starter cultures, this review examines the composition of an industrial phage collection, providing insight into the development of starter strains and cultures and the evolution of phages in the industry. Research advances in the diversity of phages and structural bases for phage-host recognition and an overview of the perpetual arms race between phage virulence and host defense are presented, with a perspective toward the development of improved phage-resistant starter culture systems.
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Affiliation(s)
- Dennis A Romero
- DuPont Nutrition and Biosciences, 3329 Agriculture Dr., Madison, WI 53716, USA
| | - Damian Magill
- DuPont Nutrition and Biosciences, CS 10010, Dangé-Saint-Romain 86220, France
| | - Anne Millen
- DuPont Nutrition and Biosciences, 3329 Agriculture Dr., Madison, WI 53716, USA
| | - Philippe Horvath
- DuPont Nutrition and Biosciences, CS 10010, Dangé-Saint-Romain 86220, France
| | - Christophe Fremaux
- DuPont Nutrition and Biosciences, CS 10010, Dangé-Saint-Romain 86220, France
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32
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Ruiz-Cruz S, Parlindungan E, Erazo Garzon A, Alqarni M, Lugli GA, Ventura M, van Sinderen D, Mahony J. Lysogenization of a Lactococcal Host with Three Distinct Temperate Phages Provides Homologous and Heterologous Phage Resistance. Microorganisms 2020; 8:microorganisms8111685. [PMID: 33138325 PMCID: PMC7693887 DOI: 10.3390/microorganisms8111685] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 10/16/2020] [Accepted: 10/27/2020] [Indexed: 01/28/2023] Open
Abstract
Lactococcus lactis is the most widely exploited microorganism in global dairy fermentations. Lactococcal strains are described as typically harboring a number of prophages in their chromosomes. The presence of such prophages may provide both advantages and disadvantages to the carrying host. Here, we describe the deliberate generation of three distinct lysogens of the model lactococcal strain 3107 and the impact of additional prophage carriage on phage-resistance and anti-microbial susceptibility. Lysogen-specific responses were observed, highlighting the unique relationship and impact of each lysogenic phage on its host. Both homologous and heterologous phage-resistance profiles were observed, highlighting the presence of possible prophage-encoded phage-resistance factors. Superinfection exclusion was among the most notable causes of heterologous phage-resistance profiles with resistance observed against members of the Skunavirus, P335, P087, and 949 lactococcal phage groups. Through these analyses, it is now possible to identify phages that may pursue similar DNA injection pathways. The generated lysogenic strains exhibited increased sensitivity to the antimicrobial compounds, nisin and lysozyme, relative to the parent strain, although it is noteworthy that the degree of sensitivity was specific to the individual (pro)phages. Overall, the findings highlight the unique impact of each prophage on a given strain and the requirement for strain-level analysis when considering the implications of lysogeny.
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Affiliation(s)
- Sofia Ruiz-Cruz
- School of Microbiology & APC Microbiome Ireland, University College Cork, Western Road, Cork T12 YT20, Ireland; (S.R.-C.); (E.P.); (A.E.G.); (M.A.)
| | - Elvina Parlindungan
- School of Microbiology & APC Microbiome Ireland, University College Cork, Western Road, Cork T12 YT20, Ireland; (S.R.-C.); (E.P.); (A.E.G.); (M.A.)
| | - Andrea Erazo Garzon
- School of Microbiology & APC Microbiome Ireland, University College Cork, Western Road, Cork T12 YT20, Ireland; (S.R.-C.); (E.P.); (A.E.G.); (M.A.)
| | - Mona Alqarni
- School of Microbiology & APC Microbiome Ireland, University College Cork, Western Road, Cork T12 YT20, Ireland; (S.R.-C.); (E.P.); (A.E.G.); (M.A.)
| | - Gabriele A. Lugli
- Laboratory of Probiogenomics, Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, 43121 Parma, Italy; (G.A.L.); (M.V.)
| | - Marco Ventura
- Laboratory of Probiogenomics, Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, 43121 Parma, Italy; (G.A.L.); (M.V.)
| | - Douwe van Sinderen
- School of Microbiology & APC Microbiome Ireland, University College Cork, Western Road, Cork T12 YT20, Ireland; (S.R.-C.); (E.P.); (A.E.G.); (M.A.)
- Correspondence: (D.v.S.); (J.M.); Tel.: +353-21-4901365 (D.v.S.); +353-21-4902443 (J.M.)
| | - Jennifer Mahony
- School of Microbiology & APC Microbiome Ireland, University College Cork, Western Road, Cork T12 YT20, Ireland; (S.R.-C.); (E.P.); (A.E.G.); (M.A.)
- Correspondence: (D.v.S.); (J.M.); Tel.: +353-21-4901365 (D.v.S.); +353-21-4902443 (J.M.)
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33
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Mahony J, Frantzen C, Vinogradov E, Sadovskaya I, Theodorou I, Kelleher P, Chapot-Chartier MP, Cambillau C, Holo H, van Sinderen D. The CWPS Rubik's cube: Linking diversity of cell wall polysaccharide structures with the encoded biosynthetic machinery of selected Lactococcus lactis strains. Mol Microbiol 2020; 114:582-596. [PMID: 32515029 DOI: 10.1111/mmi.14561] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Revised: 05/22/2020] [Accepted: 05/28/2020] [Indexed: 11/29/2022]
Abstract
The biosynthetic machinery for cell wall polysaccharide (CWPS) production in lactococci is encoded by a large gene cluster, designated cwps. This locus displays considerable variation among lactococcal genomes, previously prompting a classification into three distinct genotypes (A-C). In the present study, the cwps loci of 107 lactococcal strains were compared, revealing the presence of a fourth cwps genotype (type D). Lactococcal CWPSs are comprised of two saccharidic structures: a peptidoglycan-embedded rhamnan backbone polymer to which a surface-exposed, poly/oligosaccharidic side-chain is covalently linked. Chemical structures of the side-chain of seven lactococcal strains were elucidated, highlighting their diverse and strain-specific nature. Furthermore, a link between cwps genotype and chemical structure was derived based on the number of glycosyltransferase-encoding genes in the cwps cluster and the presence of conserved genes encoding the presumed priming glycosyltransferase. This facilitates predictions of several structural features of lactococcal CWPSs including (a) whether the CWPS possesses short oligo/polysaccharide side-chains, (b) the number of component monosaccharides in a given CWPS structure, (c) the order of monosaccharide incorporation into the repeating units of the side-chain (for C-type strains), (d) the presence of Galf and phosphodiester bonds in the side-chain, and (e) the presence of glycerol phosphate substituents in the side-chain.
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Affiliation(s)
- Jennifer Mahony
- School of Microbiology, University College Cork (UCC), Cork, Ireland.,APC Microbiome Ireland, University College Cork, Cork, Ireland
| | - Cyril Frantzen
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NULS), Ås, Norway
| | - Evgeny Vinogradov
- National Research Council Canada, Institute for Biological Sciences, Ottawa, ON, Canada
| | - Irina Sadovskaya
- Equipe BPA, Université du Littoral-Côte d'Opale, Institut Charles Violette EA 7394 USC Anses, Boulogne-sur-mer, France
| | - Ilias Theodorou
- School of Microbiology, University College Cork (UCC), Cork, Ireland
| | - Philip Kelleher
- School of Microbiology, University College Cork (UCC), Cork, Ireland.,APC Microbiome Ireland, University College Cork, Cork, Ireland
| | | | - Christian Cambillau
- School of Microbiology, University College Cork (UCC), Cork, Ireland.,Architecture et Fonction des Macromolécules Biologiques, Centre National de la Recherche Scientifique (CNRS), Marseille, France
| | - Helge Holo
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NULS), Ås, Norway
| | - Douwe van Sinderen
- School of Microbiology, University College Cork (UCC), Cork, Ireland.,APC Microbiome Ireland, University College Cork, Cork, Ireland
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34
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Mangalea MR, Duerkop BA. Fitness Trade-Offs Resulting from Bacteriophage Resistance Potentiate Synergistic Antibacterial Strategies. Infect Immun 2020; 88:e00926-19. [PMID: 32094257 PMCID: PMC7309606 DOI: 10.1128/iai.00926-19] [Citation(s) in RCA: 104] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Bacteria that cause life-threatening infections in humans are becoming increasingly difficult to treat. In some instances, this is due to intrinsic and acquired antibiotic resistance, indicating that new therapeutic approaches are needed to combat bacterial pathogens. There is renewed interest in utilizing viruses of bacteria known as bacteriophages (phages) as potential antibacterial therapeutics. However, critics suggest that similar to antibiotics, the development of phage-resistant bacteria will halt clinical phage therapy. Although the emergence of phage-resistant bacteria is likely inevitable, there is a growing body of literature showing that phage selective pressure promotes mutations in bacteria that allow them to subvert phage infection, but with a cost to their fitness. Such fitness trade-offs include reduced virulence, resensitization to antibiotics, and colonization defects. Resistance to phage nucleic acid entry, primarily via cell surface modifications, compromises bacterial fitness during antibiotic and host immune system pressure. In this minireview, we explore the mechanisms behind phage resistance in bacterial pathogens and the physiological consequences of acquiring phage resistance phenotypes. With this knowledge, it may be possible to use phages to alter bacterial populations, making them more tractable to current therapeutic strategies.
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Affiliation(s)
- Mihnea R Mangalea
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Breck A Duerkop
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, Colorado, USA
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Goulet A, Spinelli S, Mahony J, Cambillau C. Conserved and Diverse Traits of Adhesion Devices from Siphoviridae Recognizing Proteinaceous or Saccharidic Receptors. Viruses 2020; 12:E512. [PMID: 32384698 PMCID: PMC7291167 DOI: 10.3390/v12050512] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 05/02/2020] [Accepted: 05/03/2020] [Indexed: 01/30/2023] Open
Abstract
Bacteriophages can play beneficial roles in phage therapy and destruction of food pathogens. Conversely, they play negative roles as they infect bacteria involved in fermentation, resulting in serious industrial losses. Siphoviridae phages possess a long non-contractile tail and use a mechanism of infection whose first step is host recognition and binding. They have evolved adhesion devices at their tails' distal end, tuned to recognize specific proteinaceous or saccharidic receptors on the host's surface that span a large spectrum of shapes. In this review, we aimed to identify common patterns beyond this apparent diversity. To this end, we analyzed siphophage tail tips or baseplates, evaluating their known structures, where available, and uncovering patterns with bioinformatics tools when they were not. It was thereby identified that a triad formed by three proteins in complex, i.e., the tape measure protein (TMP), the distal tail protein (Dit), and the tail-associated lysozyme (Tal), is conserved in all phages. This common scaffold may harbor various functional extensions internally while it also serves as a platform for plug-in ancillary or receptor-binding proteins (RBPs). Finally, a group of siphophage baseplates involved in saccharidic receptor recognition exhibits an activation mechanism reminiscent of that observed in Myoviridae.
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Affiliation(s)
- Adeline Goulet
- Architecture et Fonction des Macromolécules Biologiques, Aix-Marseille Université, Campus de Luminy, 13288 Marseille, France;
- Architecture et Fonction des Macromolécules Biologiques, Centre National de la Recherche Scientifique (CNRS), Campus de Luminy, 13288 Marseille, France
| | - Silvia Spinelli
- Architecture et Fonction des Macromolécules Biologiques, Aix-Marseille Université, Campus de Luminy, 13288 Marseille, France;
- Architecture et Fonction des Macromolécules Biologiques, Centre National de la Recherche Scientifique (CNRS), Campus de Luminy, 13288 Marseille, France
| | - Jennifer Mahony
- School of Microbiology, University College Cork, Cork T12 YN60, Ireland;
- APC Microbiome Ireland, University College Cork, Cork T12 YN60, Ireland
| | - Christian Cambillau
- Architecture et Fonction des Macromolécules Biologiques, Aix-Marseille Université, Campus de Luminy, 13288 Marseille, France;
- Architecture et Fonction des Macromolécules Biologiques, Centre National de la Recherche Scientifique (CNRS), Campus de Luminy, 13288 Marseille, France
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Complete Structure of the Enterococcal Polysaccharide Antigen (EPA) of Vancomycin-Resistant Enterococcus faecalis V583 Reveals that EPA Decorations Are Teichoic Acids Covalently Linked to a Rhamnopolysaccharide Backbone. mBio 2020; 11:mBio.00277-20. [PMID: 32345640 PMCID: PMC7188991 DOI: 10.1128/mbio.00277-20] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Enterococci are opportunistic pathogens responsible for hospital- and community-acquired infections. All enterococci produce a surface polysaccharide called EPA (enterococcal polysaccharide antigen) required for biofilm formation, antibiotic resistance, and pathogenesis. Despite the critical role of EPA in cell growth and division and as a major virulence factor, no information is available on its structure. Here, we report the complete structure of the EPA polymer produced by the model strain E. faecalis V583. We describe the structure of the EPA backbone, made of a rhamnan hexasaccharide substituted by Glc and GlcNAc residues, and show that teichoic acids are covalently bound to this rhamnan chain, forming the so-called “EPA decorations” essential for host colonization and pathogenesis. This report represents a key step in efforts to identify the structural properties of EPA that are essential for its biological activity and to identify novel targets to develop preventive and therapeutic approaches against enterococci. All enterococci produce a complex polysaccharide called the enterococcal polysaccharide antigen (EPA). This polymer is required for normal cell growth and division and for resistance to cephalosporins and plays a critical role in host-pathogen interaction. The EPA contributes to host colonization and is essential for virulence, conferring resistance to phagocytosis during the infection. Recent studies revealed that the “decorations” of the EPA polymer, encoded by genetic loci that are variable between isolates, underpin the biological activity of this surface polysaccharide. In this work, we investigated the structure of the EPA polymer produced by the high-risk enterococcal clonal complex Enterococcus faecalis V583. We analyzed purified EPA from the wild-type strain and a mutant lacking decorations and elucidated the structure of the EPA backbone and decorations. We showed that the rhamnan backbone of EPA is composed of a hexasaccharide repeat unit of C2- and C3-linked rhamnan chains, partially substituted in the C3 position by α-glucose (α-Glc) and in the C2 position by β-N-acetylglucosamine (β-GlcNAc). The so-called “EPA decorations” consist of phosphopolysaccharide chains corresponding to teichoic acids covalently bound to the rhamnan backbone. The elucidation of the complete EPA structure allowed us to propose a biosynthetic pathway, a first essential step toward the design of antimicrobials targeting the synthesis of this virulence factor.
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Theodorou I, Courtin P, Sadovskaya I, Palussière S, Fenaille F, Mahony J, Chapot-Chartier MP, van Sinderen D. Three distinct glycosylation pathways are involved in the decoration of Lactococcus lactis cell wall glycopolymers. J Biol Chem 2020; 295:5519-5532. [PMID: 32169901 PMCID: PMC7170526 DOI: 10.1074/jbc.ra119.010844] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Revised: 03/10/2020] [Indexed: 12/16/2022] Open
Abstract
Extracytoplasmic sugar decoration of glycopolymer components of the bacterial cell wall contributes to their structural diversity. Typically, the molecular mechanism that underpins such a decoration process involves a three-component glycosylation system (TGS) represented by an undecaprenyl-phosphate (Und-P) sugar-activating glycosyltransferase (Und-P GT), a flippase, and a polytopic glycosyltransferase (PolM GT) dedicated to attaching sugar residues to a specific glycopolymer. Here, using bioinformatic analyses, CRISPR-assisted recombineering, structural analysis of cell wall-associated polysaccharides (CWPS) through MALDI-TOF MS and methylation analysis, we report on three such systems in the bacterium Lactococcus lactis On the basis of sequence similarities, we first identified three gene pairs, csdAB, csdCD, and csdEF, each encoding an Und-P GT and a PolM GT, as potential TGS component candidates. Our experimental results show that csdAB and csdCD are involved in Glc side-chain addition on the CWPS components rhamnan and polysaccharide pellicle (PSP), respectively, whereas csdEF plays a role in galactosylation of lipoteichoic acid (LTA). We also identified a potential flippase encoded in the L. lactis genome (llnz_02975, cflA) and confirmed that it participates in the glycosylation of the three cell wall glycopolymers rhamnan, PSP, and LTA, thus indicating that its function is shared by the three TGSs. Finally, we observed that glucosylation of both rhamnan and PSP can increase resistance to bacteriophage predation and that LTA galactosylation alters L. lactis resistance to bacteriocin.
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Affiliation(s)
- Ilias Theodorou
- School of Microbiology, University College Cork, Cork T12 K8AF, Ireland
| | - Pascal Courtin
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, 78350 Jouy-en-Josas, France
| | - Irina Sadovskaya
- Équipe BPA, Université du Littoral Côte d'Opale, Institut Régional Charles Violette EA 7394, USC Anses-ULCO, 62202 Boulogne-sur-Mer, France
| | - Simon Palussière
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, 78350 Jouy-en-Josas, France
| | - François Fenaille
- Université Paris-Saclay, Commissariat à l'Energie Atomique, INRAE, Médicaments et Technologies pour la Santé (MTS), MetaboHUB, 91191 Gif-sur-Yvette, France
| | - Jennifer Mahony
- School of Microbiology, University College Cork, Cork T12 K8AF, Ireland
- APC Microbiome Ireland, University College Cork, Cork T12 K8AF, Ireland
| | | | - Douwe van Sinderen
- School of Microbiology, University College Cork, Cork T12 K8AF, Ireland
- APC Microbiome Ireland, University College Cork, Cork T12 K8AF, Ireland
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38
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McDonnell B, Hanemaaijer L, Bottacini F, Kelleher P, Lavelle K, Sadovskaya I, Vinogradov E, Ver Loren van Themaat E, Kouwen T, Mahony J, van Sinderen D. A cell wall-associated polysaccharide is required for bacteriophage adsorption to the Streptococcus thermophilus cell surface. Mol Microbiol 2020; 114:31-45. [PMID: 32073719 DOI: 10.1111/mmi.14494] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2019] [Revised: 02/17/2020] [Accepted: 02/17/2020] [Indexed: 11/29/2022]
Abstract
Streptococcus thermophilus strain ST64987 was exposed to a member of a recently discovered group of S. thermophilus phages (the 987 phage group), generating phage-insensitive mutants, which were then characterized phenotypically and genomically. Decreased phage adsorption was observed in selected bacteriophage-insensitive mutants, and was partnered with a sedimenting phenotype and increased cell chain length or aggregation. Whole genome sequencing of several bacteriophage-insensitive mutants identified mutations located in a gene cluster presumed to be responsible for cell wall polysaccharide production in this strain. Analysis of cell surface-associated glycans by methylation and NMR spectroscopy revealed a complex branched rhamno-polysaccharide in both ST64987 and phage-insensitive mutant BIM3. In addition, a second cell wall-associated polysaccharide of ST64987, composed of hexasaccharide branched repeating units containing galactose and glucose, was absent in the cell wall of mutant BIM3. Genetic complementation of three phage-resistant mutants was shown to restore the carbohydrate and phage resistance profiles of the wild-type strain, establishing the role of this gene cluster in cell wall polysaccharide production and phage adsorption and, thus, infection.
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Affiliation(s)
- Brian McDonnell
- School of Microbiology and APC Microbiome Ireland, University College Cork, Cork, Ireland
| | | | - Francesca Bottacini
- School of Microbiology and APC Microbiome Ireland, University College Cork, Cork, Ireland
| | - Philip Kelleher
- School of Microbiology and APC Microbiome Ireland, University College Cork, Cork, Ireland
| | - Katherine Lavelle
- School of Microbiology and APC Microbiome Ireland, University College Cork, Cork, Ireland
| | - Irina Sadovskaya
- Équipe BPA, Université du Littoral Côte d'Opale, Institut Régional Charles Violette EA 7394, USC Anses-ULCO, Boulogne-sur-Mer, France
| | - Evgeny Vinogradov
- Institute for Biological Sciences, National Research Council of Canada, Ottawa, ON, Canada
| | | | - Thijs Kouwen
- DSM Biotechnology Center, Delft, the Netherlands
| | - Jennifer Mahony
- School of Microbiology and APC Microbiome Ireland, University College Cork, Cork, Ireland
| | - Douwe van Sinderen
- School of Microbiology and APC Microbiome Ireland, University College Cork, Cork, Ireland
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Lactococcus Ceduovirus Phages Isolated from Industrial Dairy Plants-from Physiological to Genomic Analyses. Viruses 2020; 12:v12030280. [PMID: 32138347 PMCID: PMC7150918 DOI: 10.3390/v12030280] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 02/28/2020] [Accepted: 02/28/2020] [Indexed: 12/27/2022] Open
Abstract
LactococcusCeduovirus (formerly c2virus) bacteriophages are among the three most prevalent phage types reported in dairy environments. Phages from this group conduct a strictly lytic lifestyle and cause substantial losses during milk fermentation processes, by infecting lactococcal host starter strains. Despite their deleterious activity, there are limited research data concerning Ceduovirus phages. To advance our knowledge on this specific phage group, we sequenced and performed a comparative analysis of 10 new LactococcuslactisCeduovirus phages isolated from distinct dairy environments. Host range studies allowed us to distinguish the differential patterns of infection of L. lactis cells for each phage, and revealed a broad host spectrum for most of them. We showed that 40% of the studied Ceduovirus phages can infect both cremoris and lactis strains. A preference to lyse strains with the C-type cell wall polysaccharide genotype was observed. Phage whole-genome sequencing revealed an average nucleotide identity above 80%, with distinct regions of divergence mapped to several locations. The comparative approach for analyzing genomic data and the phage lytic spectrum suggested that the amino acid sequence of the orf8-encoded putative tape measure protein correlates with host range. Phylogenetic studies revealed separation of the sequenced phages into two subgroups. Finally, we identified three types of phage origin of replication regions, and showed they are able to support plasmid replication without additional phage proteins.
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40
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Theodorou I, Courtin P, Palussière S, Kulakauskas S, Bidnenko E, Péchoux C, Fenaille F, Penno C, Mahony J, van Sinderen D, Chapot-Chartier MP. A dual-chain assembly pathway generates the high structural diversity of cell-wall polysaccharides in Lactococcus lactis. J Biol Chem 2019; 294:17612-17625. [PMID: 31582566 DOI: 10.1074/jbc.ra119.009957] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Revised: 09/30/2019] [Indexed: 12/12/2022] Open
Abstract
In Lactococcus lactis, cell-wall polysaccharides (CWPSs) act as receptors for many bacteriophages, and their structural diversity among strains explains, at least partially, the narrow host range of these viral predators. Previous studies have reported that lactococcal CWPS consists of two distinct components, a variable chain exposed at the bacterial surface, named polysaccharide pellicle (PSP), and a more conserved rhamnan chain anchored to, and embedded inside, peptidoglycan. These two chains appear to be covalently linked to form a large heteropolysaccharide. The molecular machinery for biosynthesis of both components is encoded by a large gene cluster, named cwps In this study, using a CRISPR/Cas-based method, we performed a mutational analysis of the cwps genes. MALDI-TOF MS-based structural analysis of the mutant CWPS combined with sequence homology, transmission EM, and phage sensitivity analyses enabled us to infer a role for each protein encoded by the cwps cluster. We propose a comprehensive CWPS biosynthesis scheme in which the rhamnan and PSP chains are independently synthesized from two distinct lipid-sugar precursors and are joined at the extracellular side of the cytoplasmic membrane by a mechanism involving a membrane-embedded glycosyltransferase with a GT-C fold. The proposed scheme encompasses a system that allows extracytoplasmic modification of rhamnan by complex substituting oligo-/polysaccharides. It accounts for the extensive diversity of CWPS structures observed among lactococci and may also have relevance to the biosynthesis of complex rhamnose-containing CWPSs in other Gram-positive bacteria.
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Affiliation(s)
- Ilias Theodorou
- School of Microbiology, University College Cork, Western Road, Cork, Ireland.,APC Microbiome Ireland, University College Cork, Western Road, Cork, Ireland
| | - Pascal Courtin
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, 78350 Jouy-en-Josas, France
| | - Simon Palussière
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, 78350 Jouy-en-Josas, France
| | - Saulius Kulakauskas
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, 78350 Jouy-en-Josas, France
| | - Elena Bidnenko
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, 78350 Jouy-en-Josas, France
| | - Christine Péchoux
- INRA, UMR 1313 Génétique Animale et Biologie Intégrative (GABI), Plate-forme MIMA2, 78350 Jouy-en-Josas, France
| | - François Fenaille
- CEA, Institut Joliot, Service de Pharmacologie et d'Immunoanalyse, UMR 0496, Laboratoire d'Etude du Métabolisme des Médicaments, MetaboHUB-Paris, Université Paris-Saclay, 91191 Gif-sur-Yvette, France
| | - Christophe Penno
- School of Microbiology, University College Cork, Western Road, Cork, Ireland.,APC Microbiome Ireland, University College Cork, Western Road, Cork, Ireland
| | - Jennifer Mahony
- School of Microbiology, University College Cork, Western Road, Cork, Ireland.,APC Microbiome Ireland, University College Cork, Western Road, Cork, Ireland
| | - Douwe van Sinderen
- School of Microbiology, University College Cork, Western Road, Cork, Ireland .,APC Microbiome Ireland, University College Cork, Western Road, Cork, Ireland
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41
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A Specific Sugar Moiety in the Lactococcus lactis Cell Wall Pellicle Is Required for Infection by CHPC971, a Member of the Rare 1706 Phage Species. Appl Environ Microbiol 2019; 85:AEM.01224-19. [PMID: 31350317 DOI: 10.1128/aem.01224-19] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Accepted: 07/17/2019] [Indexed: 12/29/2022] Open
Abstract
Lactococcus lactis is a Gram-positive bacterium widely used as a starter culture for the production of different dairy products, especially a large variety of cheeses. Infection of lactococcal starter cultures by bacteriophages is one of the major causes of fermentation failure and often leads to production halt. Lactococcal bacteriophages belonging to the c2, 936, and P335 species are the most commonly isolated in dairy plants and have been extensively investigated in the past three decades. Information regarding bacteriophages belonging to less commonly isolated species is, on the other hand, less extensive, although these phages can also contribute to starter culture infection. Here, we report the nucleotide sequence of the newly isolated L. lactis phage CHPC971, belonging to the rare 1706 species of lactococcal phages. We investigated the nature of the host receptor recognized by the phage and collected evidence that strongly suggests that it binds to a specific sugar moiety in the cell wall pellicle of its host. An in silico analysis of the genome of phage CHPC971 identified the hypothetical genes involved in receptor binding.IMPORTANCE Gathering information on how lactococcal bacteriophages recognize their host and proliferate in the dairy environment is of vital importance for the establishment of proper starter culture rotation plans and to avoid fermentation failure and consequent great economic losses for dairy industries. We provide strong evidence on the type of receptor recognized by a newly isolated 1706-type lactococcal bacteriophage, increasing knowledge of phage-host interactions relevant to dairying. This information can help to prevent phage infection events that, so far, are hard to predict and avoid.
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42
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Ubiquitous Carbohydrate Binding Modules Decorate 936 Lactococcal Siphophage Virions. Viruses 2019; 11:v11070631. [PMID: 31324000 PMCID: PMC6669499 DOI: 10.3390/v11070631] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Revised: 07/01/2019] [Accepted: 07/04/2019] [Indexed: 01/29/2023] Open
Abstract
With the availability of an increasing number of 3D structures of bacteriophage components, combined with powerful in silico predictive tools, it has become possible to decipher the structural assembly and functionality of phage adhesion devices. In the current study, we examined 113 members of the 936 group of lactococcal siphophages, and identified a number of Carbohydrate Binding Modules (CBMs) in the neck passage structure and major tail protein, on top of evolved Dit proteins, as recently reported by us. The binding ability of such CBM-containing proteins was assessed through the construction of green fluorescent protein fusion proteins and subsequent binding assays. Two CBMs, one from the phage tail and another from the neck, demonstrated definite binding to their phage-specific host. Bioinformatic analysis of the structural proteins of 936 phages reveals that they incorporate binding modules which exhibit structural homology to those found in other lactococcal phage groups and beyond, indicating that phages utilize common structural “bricks” to enhance host binding capabilities. The omnipresence of CBMs in Siphophages supports their beneficial role in the infection process, as they can be combined in various ways to form appendages with different shapes and functionalities, ensuring their success in host detection in their respective ecological niches.
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43
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Understanding and Exploiting Phage-Host Interactions. Viruses 2019; 11:v11060567. [PMID: 31216787 PMCID: PMC6630733 DOI: 10.3390/v11060567] [Citation(s) in RCA: 99] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Revised: 06/07/2019] [Accepted: 06/10/2019] [Indexed: 01/05/2023] Open
Abstract
Initially described a century ago by William Twort and Felix d’Herelle, bacteriophages are bacterial viruses found ubiquitously in nature, located wherever their host cells are present. Translated literally, bacteriophage (phage) means ‘bacteria eater’. Phages interact and infect specific bacteria while not affecting other bacteria or cell lines of other organisms. Due to the specificity of these phage–host interactions, the relationship between phages and their host cells has been the topic of much research. The advances in phage biology research have led to the exploitation of these phage–host interactions and the application of phages in the agricultural and food industry. Phages may provide an alternative to the use of antibiotics, as it is well known that the emergence of antibiotic-resistant bacterial infections has become an epidemic in clinical settings. In agriculture, pre-harvest and/or post-harvest application of phages to crops may prevent the colonisation of bacteria that are detrimental to plant or human health. In addition, the abundance of data generated from genome sequencing has allowed the development of phage-derived bacterial detection systems of foodborne pathogens. This review aims to outline the specific interactions between phages and their host and how these interactions may be exploited and applied in the food industry.
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44
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Kelleher P, Mahony J, Bottacini F, Lugli GA, Ventura M, van Sinderen D. The Lactococcus lactis Pan-Plasmidome. Front Microbiol 2019; 10:707. [PMID: 31019500 PMCID: PMC6458302 DOI: 10.3389/fmicb.2019.00707] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Accepted: 03/20/2019] [Indexed: 01/01/2023] Open
Abstract
Plasmids are autonomous, self-replicating, extrachromosomal genetic elements that are typically not essential for growth of their host. They may encode metabolic capabilities, which promote the maintenance of these genetic elements, and may allow adaption to specific ecological niches and consequently enhance survival. Genome sequencing of 16 Lactococcus lactis strains revealed the presence of 83 plasmids, including two megaplasmids. The limitations of Pacific Biosciences SMRT sequencing in detecting the total plasmid complement of lactococcal strains is examined, while a combined Illumina/SMRT sequencing approach is proposed to combat these issues. Comparative genome analysis of these plasmid sequences combined with other publicly available plasmid sequence data allowed the definition of the lactococcal plasmidome, and facilitated an investigation into (bio) technologically important plasmid-encoded traits such as conjugation, bacteriocin production, exopolysaccharide (EPS) production, and (bacterio) phage resistance.
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Affiliation(s)
- Philip Kelleher
- School of Microbiology, University College Cork, Cork, Ireland
- APC Microbiome Ireland, University College Cork, Cork, Ireland
| | - Jennifer Mahony
- School of Microbiology, University College Cork, Cork, Ireland
- APC Microbiome Ireland, University College Cork, Cork, Ireland
| | | | - Gabriele A. Lugli
- Laboratory of Probiogenomics, Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parma, Italy
| | - Marco Ventura
- Laboratory of Probiogenomics, Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parma, Italy
| | - Douwe van Sinderen
- School of Microbiology, University College Cork, Cork, Ireland
- APC Microbiome Ireland, University College Cork, Cork, Ireland
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45
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Sadiq FA, He G, Sakandar HA, Li Y, Ou K. Lactococcus lactis phages from the perspective of their diversity, thermal and biocidal resistance. Int Dairy J 2019. [DOI: 10.1016/j.idairyj.2018.11.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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46
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Wels M, Siezen R, van Hijum S, Kelly WJ, Bachmann H. Comparative Genome Analysis of Lactococcus lactis Indicates Niche Adaptation and Resolves Genotype/Phenotype Disparity. Front Microbiol 2019; 10:4. [PMID: 30766512 PMCID: PMC6365430 DOI: 10.3389/fmicb.2019.00004] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Accepted: 01/07/2019] [Indexed: 01/21/2023] Open
Abstract
Lactococcus lactis is one of the most important micro-organisms in the dairy industry for the fermentation of cheese and buttermilk. Besides the conversion of lactose to lactate it is responsible for product properties such as flavor and texture, which are determined by volatile metabolites, proteolytic activity and exopolysaccharide production. While the species Lactococcus lactis consists of the two subspecies lactis and cremoris their taxonomic position is confused by a group of strains that, despite of a cremoris genotype, display a lactis phenotype. Here we compared and analyzed the (draft) genomes of 43 L. lactis strains, of which 19 are of dairy and 24 are of non-dairy origin. Machine-learning algorithms facilitated the identification of orthologous groups of protein sequences (OGs) that are predictors for either the taxonomic position or the source of isolation. This allowed the unambiguous categorization of the genotype/phenotype disparity of ssp. lactis and ssp. cremoris strains. A detailed analysis of phenotypic properties including plasmid-encoded genes indicates evolutionary changes during niche adaptations. The results are consistent with the hypothesis that dairy isolates evolved from plant isolates. The analysis further suggests that genomes of cremoris phenotype strains are so eroded that they are restricted to a dairy environment. Overall the genome comparison of a diverse set of strains allowed the identification of niche and subspecies specific genes. This explains evolutionary relationships and will aid the identification and selection of industrial starter cultures.
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Affiliation(s)
- Michiel Wels
- NIZO Food Research B.V., Ede, Netherlands.,TI Food and Nutrition, Wageningen, Netherlands
| | - Roland Siezen
- TI Food and Nutrition, Wageningen, Netherlands.,Centre for Molecular and Biomolecular Informatics, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, Netherlands.,Microbial Bioinformatics, Ede, Netherlands
| | - Sacha van Hijum
- NIZO Food Research B.V., Ede, Netherlands.,TI Food and Nutrition, Wageningen, Netherlands.,Centre for Molecular and Biomolecular Informatics, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, Netherlands
| | | | - Herwig Bachmann
- NIZO Food Research B.V., Ede, Netherlands.,TI Food and Nutrition, Wageningen, Netherlands.,Systems Bioinformatics, Vrije Universiteit Amsterdam, Amsterdam, Netherlands
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47
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Enterococcus faecalis Countermeasures Defeat a Virulent Picovirinae Bacteriophage. Viruses 2019; 11:v11010048. [PMID: 30634666 PMCID: PMC6356687 DOI: 10.3390/v11010048] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Revised: 12/29/2018] [Accepted: 12/31/2018] [Indexed: 12/23/2022] Open
Abstract
Enterococcus faecalis is an opportunistic pathogen that has emerged as a major cause of nosocomial infections worldwide. Many clinical strains are indeed resistant to last resort antibiotics and there is consequently a reawakening of interest in exploiting virulent phages to combat them. However, little is still known about phage receptors and phage resistance mechanisms in enterococci. We made use of a prophageless derivative of the well-known clinical strain E. faecalis V583 to isolate a virulent phage belonging to the Picovirinae subfamily and to the P68 genus that we named Idefix. Interestingly, most isolates of E. faecalis tested—including V583—were resistant to this phage and we investigated more deeply into phage resistance mechanisms. We found that E. faecalis V583 prophage 6 was particularly efficient in resisting Idefix infection thanks to a new abortive infection (Abi) mechanism, which we designated Abiα. It corresponded to the Pfam domain family with unknown function DUF4393 and conferred a typical Abi phenotype by causing a premature lysis of infected E. faecalis. The abiα gene is widespread among prophages of enterococci and other Gram-positive bacteria. Furthermore, we identified two genes involved in the synthesis of the side chains of the surface rhamnopolysaccharide that are important for Idefix adsorption. Interestingly, mutants in these genes arose at a frequency of ~10−4 resistant mutants per generation, conferring a supplemental bacterial line of defense against Idefix.
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Sadovskaya I, Guérardel Y. Simple Protocol to Purify Cell Wall Polysaccharide from Gram-Positive Bacteria and Assess Its Structural Integrity. Methods Mol Biol 2019; 1954:37-45. [PMID: 30864122 DOI: 10.1007/978-1-4939-9154-9_4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Cell wall polysaccharides (CWPS), which are usually covalently bound to the peptidoglycan and are closely associated with the cell wall, are considered as ubiquitous components of the cell envelope of gram-positive bacteria and play an important role as mediators of bacterial interactions with the environment. Here, we describe a simple method for purifying CWPS by extraction of bacterial cells with consecutive acid treatments. Purified CWPS are obtained by gel-filtration chromatography following treatment with HF. We also provide the methodology to easily assess the integrity of CWPS using high-resolution magic-angle spinning (HR-MAS) NMR.
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Affiliation(s)
- Irina Sadovskaya
- Équipe BPA, Univ. Littoral Côte d'Opale, convention ANSES, EA 7394, ICV Charles Violette, Univ. Lille, Univ. Artois, INRA, ISA F-62321, Boulogne-sur-mer, France
| | - Yann Guérardel
- Univ. Lille, CNRS, UMR 8576 - UGSF - Unité de Glycobiologie Structurale et Fonctionnelle, Lille, France.
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Cell Wall Glycans Mediate Recognition of the Dairy Bacterium Streptococcus thermophilus by Bacteriophages. Appl Environ Microbiol 2018; 84:AEM.01847-18. [PMID: 30242010 PMCID: PMC6238053 DOI: 10.1128/aem.01847-18] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Accepted: 09/14/2018] [Indexed: 01/21/2023] Open
Abstract
Streptococcus thermophilus is widely used in starter cultures for cheese and yoghurt production. During dairy fermentations, infections of bacteria with bacteriophages result in acidification failures and a lower quality of the final products. An understanding of the molecular factors involved in phage-host interactions, in particular, the phage receptors in dairy bacteria, is a crucial step for developing better strategies to prevent phage infections in dairy plants. Receptors on the cell surfaces of bacterial hosts are essential during the infection cycle of bacteriophages. To date, the phage receptors of the industrial relevant dairy starter bacterium Streptococcus thermophilus remain elusive. Thus, we set out to identify cell surface structures that are involved in host recognition by dairy streptococcal phages. Five industrial S. thermophilus strains sensitive to different phages (pac type, cos type, and the new type 987), were selected to generate spontaneous bacteriophage-insensitive mutants (BIMs). Of these, approximately 50% were deselected as clustered regularly interspaced short palindromic repeat (CRISPR) mutants, while the other pool was further characterized to identify receptor mutants. On the basis of genome sequencing data, phage resistance in putative receptor mutants was attributed to nucleotide changes in genes encoding glycan biosynthetic pathways. Superresolution structured illumination microscopy was used to visualize the interactions between S. thermophilus and its phages. The phages were either regularly distributed along the cells or located at division sites of the cells. The cell wall structures mediating the latter type of phage adherence were further analyzed via phenotypic and biochemical assays. Altogether, our data suggested that phage adsorption to S. thermophilus is mediated by glycans associated with the bacterial cell surface. Specifically, the pac-type phage CHPC951 adsorbed to polysaccharides anchored to peptidoglycan, while the 987-type phage CHPC926 recognized exocellular polysaccharides associated with the cell surface. IMPORTANCEStreptococcus thermophilus is widely used in starter cultures for cheese and yoghurt production. During dairy fermentations, infections of bacteria with bacteriophages result in acidification failures and a lower quality of the final products. An understanding of the molecular factors involved in phage-host interactions, in particular, the phage receptors in dairy bacteria, is a crucial step for developing better strategies to prevent phage infections in dairy plants.
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López-González MJ, Escobedo S, Rodríguez A, Neves AR, Janzen T, Martínez B. Adaptive Evolution of Industrial Lactococcus lactis Under Cell Envelope Stress Provides Phenotypic Diversity. Front Microbiol 2018; 9:2654. [PMID: 30455679 PMCID: PMC6230721 DOI: 10.3389/fmicb.2018.02654] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Accepted: 10/17/2018] [Indexed: 12/14/2022] Open
Abstract
Lactococcus lactis is widely used as a starter in the manufacture of cheese and fermented milk. Its main role is the production of lactic acid, but also contributes to the sensory attributes of cheese. Unfortunately, the diversity of suitable strains to be commercialized as dairy starters is limited. In this work, we have applied adaptive evolution under cell envelope stress (AE-CES) as means to provide evolved L. lactis strains with distinct physiological and metabolic traits. A total of seven strains, three of industrial origin and four wild nisin Z-producing L. lactis, were exposed to subinhibitory concentrations of Lcn972, a bacteriocin that triggers the cell envelope stress response in L. lactis. Stable Lcn972 resistant (Lcn972R) mutants were obtained from all of them and two mutants per strain were further characterized. Minimal inhibitory Lcn972 concentrations increased from 4- to 32-fold compared to their parental strains and the Lcn972R mutants retained similar growth parameters in broth. All the mutants acidified milk to a pH below 5.3 with the exception of one that lost the lactose plasmid during adaptation and was unable to grow in milk, and two others with slower acidification rates in milk. While in general phage susceptibility was unaltered, six mutants derived from three nisin Z producers became more sensitive to phage attack. Loss of a putative plasmid-encoded anti-phage mechanism appeared to be the reason for phage susceptibility. Otherwise, nisin production in milk was not compromised. Different inter- and intra-strain-dependent phenotypes were observed encompassing changes in cell surface hydrophobicity and in their autolytic profile with Lcn972R mutants being, generally, less autolytic. Resistance to other antimicrobials revealed cross-protection mainly to cell wall-active antimicrobials such as lysozyme, bacitracin, and vancomycin. Finally, distinct and shared non-synonymous mutations were detected in the draft genome of the Lcn972R mutants. Depending on the parental strain, mutations were found in genes involved in stress response, detoxification modules, cell envelope biogenesis and/or nucleotide metabolism. As a whole, the results emphasize the different strategies by which each strain becomes resistant to Lcn972 and supports the feasibility of AE-CES as a novel platform to introduce diversity within industrial L. lactis dairy starters.
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Affiliation(s)
- María Jesús López-González
- DairySafe Group, Instituto de Productos Lácteos de Asturias (IPLA)-Consejo Superior de Investigaciones Científicas (CSIC), Villaviciosa, Spain
| | - Susana Escobedo
- DairySafe Group, Instituto de Productos Lácteos de Asturias (IPLA)-Consejo Superior de Investigaciones Científicas (CSIC), Villaviciosa, Spain
| | - Ana Rodríguez
- DairySafe Group, Instituto de Productos Lácteos de Asturias (IPLA)-Consejo Superior de Investigaciones Científicas (CSIC), Villaviciosa, Spain
| | | | | | - Beatriz Martínez
- DairySafe Group, Instituto de Productos Lácteos de Asturias (IPLA)-Consejo Superior de Investigaciones Científicas (CSIC), Villaviciosa, Spain
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