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Figueroa-Gonzalez PA, Bornemann TLV, Hinzke T, Maaß S, Trautwein-Schult A, Starke J, Moore CJ, Esser SP, Plewka J, Hesse T, Schmidt TC, Schreiber U, Bor B, Becher D, Probst AJ. Metaproteogenomics resolution of a high-CO 2 aquifer community reveals a complex cellular adaptation of groundwater Gracilibacteria to a host-dependent lifestyle. MICROBIOME 2024; 12:194. [PMID: 39369255 PMCID: PMC11452946 DOI: 10.1186/s40168-024-01889-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Accepted: 07/29/2024] [Indexed: 10/07/2024]
Abstract
BACKGROUND Bacteria of the candidate phyla radiation (CPR), constituting about 25% of the bacterial biodiversity, are characterized by small cell size and patchy genomes without complete key metabolic pathways, suggesting a symbiotic lifestyle. Gracilibacteria (BD1-5), which are part of the CPR branch, possess alternate coded genomes and have not yet been cultivated. The lifestyle of Gracilibacteria, their temporal dynamics, and activity in natural ecosystems, particularly in groundwater, has remained largely unexplored. Here, we aimed to investigate Gracilibacteria activity in situ and to discern their lifestyle based on expressed genes, using the metaproteogenome of Gracilibacteria as a function of time in the cold-water geyser Wallender Born in the Volcanic Eifel region in Germany. RESULTS We coupled genome-resolved metagenomics and metaproteomics to investigate a cold-water geyser microbial community enriched in Gracilibacteria across a 12-day time-series. Groundwater was collected and sequentially filtered to fraction CPR and other bacteria. Based on 725 Gbps of metagenomic data, 1129 different ribosomal protein S3 marker genes, and 751 high-quality genomes (123 population genomes after dereplication), we identified dominant bacteria belonging to Gallionellales and Gracilibacteria along with keystone microbes, which were low in genomic abundance but substantially contributing to proteomic abundance. Seven high-quality Gracilibacteria genomes showed typical limitations, such as limited amino acid or nucleotide synthesis, in their central metabolism but no co-occurrence with potential hosts. The genomes of these Gracilibacteria were encoded for a high number of proteins involved in cell to cell interaction, supporting the previously surmised host-dependent lifestyle, e.g., type IV and type II secretion system subunits, transporters, and features related to cell motility, which were also detected on protein level. CONCLUSIONS We here identified microbial keystone taxa in a high-CO2 aquifer, and revealed microbial dynamics of Gracilibacteria. Although Gracilibacteria in this ecosystem did not appear to target specific organisms in this ecosystem due to lack of co-occurrence despite enrichment on 0.2-µm filter fraction, we provide proteomic evidence for the complex machinery behind the host-dependent lifestyle of groundwater Gracilibacteria. Video Abstract.
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Affiliation(s)
- Perla Abigail Figueroa-Gonzalez
- Environmental Metagenomics, Faculty of Chemistry, Research Center One Health of the University Alliance Ruhr, University of Duisburg-Essen, 45151, Essen, Germany
| | - Till L V Bornemann
- Environmental Metagenomics, Faculty of Chemistry, Research Center One Health of the University Alliance Ruhr, University of Duisburg-Essen, 45151, Essen, Germany
- Centre of Water and Environmental Research (ZWU), University of Duisburg-Essen, 45141, Essen, Germany
| | - Tjorven Hinzke
- Microbial Proteomics, Institute of Microbiology, University of Greifswald, 17489, Greifswald, Germany
- Department of Pathogen Evolution, Helmholtz Institute for One Health, 17489, Greifswald, Germany
- Microbial Physiology and Molecular Biology, Institute of Microbiology, University of Greifswald, Greifswald, 17489, Germany
| | - Sandra Maaß
- Microbial Proteomics, Institute of Microbiology, University of Greifswald, 17489, Greifswald, Germany
| | - Anke Trautwein-Schult
- Microbial Proteomics, Institute of Microbiology, University of Greifswald, 17489, Greifswald, Germany
| | - Joern Starke
- Environmental Metagenomics, Faculty of Chemistry, Research Center One Health of the University Alliance Ruhr, University of Duisburg-Essen, 45151, Essen, Germany
| | - Carrie J Moore
- Environmental Metagenomics, Faculty of Chemistry, Research Center One Health of the University Alliance Ruhr, University of Duisburg-Essen, 45151, Essen, Germany
| | - Sarah P Esser
- Environmental Metagenomics, Faculty of Chemistry, Research Center One Health of the University Alliance Ruhr, University of Duisburg-Essen, 45151, Essen, Germany
| | - Julia Plewka
- Environmental Metagenomics, Faculty of Chemistry, Research Center One Health of the University Alliance Ruhr, University of Duisburg-Essen, 45151, Essen, Germany
| | - Tobias Hesse
- Instrumental Analytical Chemistry and Centre for Water and Environmental Research (ZWU), University of Duisburg-Essen, Essen, 45141, Germany
| | - Torsten C Schmidt
- Centre of Water and Environmental Research (ZWU), University of Duisburg-Essen, 45141, Essen, Germany
- Instrumental Analytical Chemistry and Centre for Water and Environmental Research (ZWU), University of Duisburg-Essen, Essen, 45141, Germany
| | - Ulrich Schreiber
- Department of Geology, University of Duisburg-Essen, 45141, Essen, Germany
| | - Batbileg Bor
- Microbiology, The Forsyth Institute, Cambridge, MA, 02142, USA
| | - Dörte Becher
- Microbial Proteomics, Institute of Microbiology, University of Greifswald, 17489, Greifswald, Germany
| | - Alexander J Probst
- Environmental Metagenomics, Faculty of Chemistry, Research Center One Health of the University Alliance Ruhr, University of Duisburg-Essen, 45151, Essen, Germany.
- Centre of Water and Environmental Research (ZWU), University of Duisburg-Essen, 45141, Essen, Germany.
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Jang H, Kim CM, Ha HJ, Hong E, Park HH. Interdomain flexibility and putative active site was revealed by crystal structure of MltG from Acinetobacter baumannii. Biochem Biophys Res Commun 2024; 727:150318. [PMID: 38945066 DOI: 10.1016/j.bbrc.2024.150318] [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: 06/23/2024] [Revised: 06/24/2024] [Accepted: 06/26/2024] [Indexed: 07/02/2024]
Abstract
MltG, positioned within the inner membrane of bacteria, functions as a lytic transglycosylase (LT) essential for integrating into the cell wall by cleaving the newly synthesized glycan strand, emphasizing its critical involvement in bacterial cell wall biosynthesis and remodeling. Current study reported the first structure of MltG family of LT. We have elucidated the structure of MltG from Acinetobacter baumannii (abMltG), a formidable superbug renowned for its remarkable antibiotic resistance. Our structural and biochemical investigations unveiled the presence of a flexible peptidoglycan (PG)-binding domain (PGD) within MltG family, which exists as a monomer in solution. Furthermore, we delineated the putative active site of abMltG via a combination of structural analysis and sequence comparison. This discovery enhances our comprehension of the transglycosylation process mediated by the MltG family, offering insights that could inform the development of novel antibiotics tailored to combat A. baumannii.
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Affiliation(s)
- Hyunseok Jang
- College of Pharmacy, Chung-Ang University, Seoul, 06974, Republic of Korea; Department of Global Innovative Drugs, Graduate School of Chung-Ang University, Seoul, 06974, Republic of Korea
| | - Chang Min Kim
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Hyun Ji Ha
- College of Pharmacy, Chung-Ang University, Seoul, 06974, Republic of Korea; Department of Global Innovative Drugs, Graduate School of Chung-Ang University, Seoul, 06974, Republic of Korea
| | - Eunmi Hong
- New Drug Development Center, Daegu-Gyeongbuk Medical Innovation Foundation, Daegu, 41061, Republic of Korea
| | - Hyun Ho Park
- College of Pharmacy, Chung-Ang University, Seoul, 06974, Republic of Korea; Department of Global Innovative Drugs, Graduate School of Chung-Ang University, Seoul, 06974, Republic of Korea.
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Papayova K, Bocanova L, Bauerova V, Bauer J, Halgasova N, Kajsikova M, Bukovska G. From sequence to function: Exploring biophysical properties of bacteriophage BFK20 lytic transglycosylase domain from the minor tail protein gp15. BIOCHIMICA ET BIOPHYSICA ACTA. PROTEINS AND PROTEOMICS 2024; 1873:141044. [PMID: 39218139 DOI: 10.1016/j.bbapap.2024.141044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2024] [Revised: 08/20/2024] [Accepted: 08/27/2024] [Indexed: 09/04/2024]
Abstract
Bacteriophages have evolved different mechanisms of infection and penetration of bacterial cell walls. In Siphoviridae-like viruses, the inner tail proteins have a pivotal role in these processes and often encode lytic protein domains which increase infection efficiency. A soluble lytic transglycosylase (SLT) domain was identified in the minor tail protein gp15 from the BFK20 bacteriophage. Six fragments containing this SLT domain with adjacent regions of different lengths were cloned, expressed and purified. The biophysical properties of the two best expressing fragments were characterized by nanoDSF and CD spectroscopy, which showed that both fragments had a high refolding ability of 90 %. 3D modeling indicated that the bacteriophage BFK20 SLT domain is structurally similar to lysozyme. The degradation activity of these SLT proteins was evaluated using a lysozyme activity assay. BFK20 might use its transglycosylase activity to allow efficient phage DNA entry into the host cell by degrading bacterial peptidoglycan.
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Affiliation(s)
- Kristina Papayova
- Department of Genomics and Biotechnology, Institute of Molecular Biology, Slovak Academy of Sciences, Dubravska cesta 21, 845 51 Bratislava, Slovakia.
| | - Lucia Bocanova
- Department of Genomics and Biotechnology, Institute of Molecular Biology, Slovak Academy of Sciences, Dubravska cesta 21, 845 51 Bratislava, Slovakia.
| | - Vladena Bauerova
- Department of Biochemistry and Protein Structure, Institute of Molecular Biology, Slovak Academy of Sciences, Dubravska cesta 21, 845 51 Bratislava, Slovakia.
| | - Jacob Bauer
- Department of Biochemistry and Protein Structure, Institute of Molecular Biology, Slovak Academy of Sciences, Dubravska cesta 21, 845 51 Bratislava, Slovakia.
| | - Nora Halgasova
- Department of Genomics and Biotechnology, Institute of Molecular Biology, Slovak Academy of Sciences, Dubravska cesta 21, 845 51 Bratislava, Slovakia.
| | - Maria Kajsikova
- Department of Genomics and Biotechnology, Institute of Molecular Biology, Slovak Academy of Sciences, Dubravska cesta 21, 845 51 Bratislava, Slovakia.
| | - Gabriela Bukovska
- Department of Genomics and Biotechnology, Institute of Molecular Biology, Slovak Academy of Sciences, Dubravska cesta 21, 845 51 Bratislava, Slovakia.
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Lyu Z, Yang X, Yahashiri A, Ha S, McCausland JW, Chen X, Britton BM, Weiss DS, Xiao J. E. coli FtsN coordinates synthesis and degradation of septal peptidoglycan by partitioning between a synthesis track and a denuded glycan track. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.13.594014. [PMID: 39253420 PMCID: PMC11383011 DOI: 10.1101/2024.05.13.594014] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/11/2024]
Abstract
The E. coli cell division protein FtsN was proposed to coordinate septal peptidoglycan (sPG) synthesis and degradation to ensure robust cell wall constriction without lethal lesions. Although the precise mechanism remains unclear, previous work highlights the importance of two FtsN domains: the E domain, which interacts with and activates the sPG synthesis complex FtsWIQLB, and the SPOR domain, which binds to denuded glycan (dnG) strands, key intermediates in sPG degradation. Here, we used single-molecule tracking of FtsN and FtsW (a proxy for the sPG synthesis complex FtsWIQLB) to investigate how FtsN coordinates the two opposing processes. We observed dynamic behaviors indicating that FtsN's SPOR domain binds to dnGs cooperatively, which both sequesters the sPG synthesis complex on dnG (termed as the dnG-track) and protects dnGs from degradation by lytic transglycosylases (LTs). The release of the SPOR domain from dnGs leads to activating the sPG synthesis complex on the sPG-track and simultaneously exposing those same dnGs to degradation. Furthermore, FtsN's SPOR domain self-interacts and facilitates the formation of a multimeric sPG synthesis complex on both tracks. The cooperative self-interaction of the SPOR domain creates a sensitive switch to regulate the partitioning of FtsN between the dnG- and sPG-tracks, thereby controlling the balance between sequestered and active populations of the sPG synthesis complex. As such, FtsN coordinates sPG synthesis and degradation in space and time.
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Li X, Ren Q, Sun Z, Wu Y, Pan H. Resuscitation Promotion Factor: A Pronounced Bacterial Cytokine in Propelling Bacterial Resuscitation. Microorganisms 2024; 12:1528. [PMID: 39203370 PMCID: PMC11356341 DOI: 10.3390/microorganisms12081528] [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: 07/06/2024] [Revised: 07/19/2024] [Accepted: 07/24/2024] [Indexed: 09/03/2024] Open
Abstract
While confronted with unfavorable growth conditions, bacteria may transform into the dormant state, such as viable but nonculturable (VBNC) state, which is a reversible state characterized by low metabolic activity and lack of division. These dormant cells can be reactivated through the influence of the resuscitation promoting factor (Rpf) family, which are classified as autocrine growth factors and possess peptidoglycan hydrolase activities. To date, with the significant resuscitation or growth promotion ability of Rpf, it has been extensively applied to increasing bacterial diversity and isolating functional microbial species. This review provides a comprehensive analysis of the distribution, mode of action, and functional mechanisms of Rpf proteins in various bacterial species. The aim is to create opportunities for decoding microbial communities and extracting microbial resources from real samples across different research fields.
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Affiliation(s)
| | | | | | | | - Hanxu Pan
- School of Light Industry Science and Engineering, Beijing Technology and Business University, Beijing 100048, China; (X.L.); (Q.R.); (Z.S.); (Y.W.)
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Kaul M, Meher SK, Nallamotu KC, Reddy M. Glycan strand cleavage by a lytic transglycosylase, MltD contributes to the expansion of peptidoglycan in Escherichia coli. PLoS Genet 2024; 20:e1011161. [PMID: 38422114 DOI: 10.1371/journal.pgen.1011161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Revised: 03/12/2024] [Accepted: 01/31/2024] [Indexed: 03/02/2024] Open
Abstract
Peptidoglycan (PG) is a protective sac-like exoskeleton present in most bacterial cell walls. It is a large, covalently crosslinked mesh-like polymer made up of many glycan strands cross-bridged to each other by short peptide chains. Because PG forms a continuous mesh around the bacterial cytoplasmic membrane, opening the mesh is critical to generate space for the incorporation of new material during its expansion. In Escherichia coli, the 'space-making activity' is known to be achieved by cleavage of crosslinks between the glycan strands by a set of redundant PG endopeptidases whose absence leads to rapid lysis and cell death. Here, we demonstrate a hitherto unknown role of glycan strand cleavage in cell wall expansion in E. coli. We find that overexpression of a membrane-bound lytic transglycosylase, MltD that cuts the glycan polymers of the PG sacculus rescues the cell lysis caused by the absence of essential crosslink-specific endopeptidases, MepS, MepM and MepH. We find that cellular MltD levels are stringently controlled by two independent regulatory pathways; at the step of post-translational stability by a periplasmic adaptor-protease complex, NlpI-Prc, and post-transcriptionally by RpoS, a stationary-phase specific sigma factor. Further detailed genetic and biochemical analysis implicated a role for MltD in cleaving the nascent uncrosslinked glycan strands generated during the expansion of PG. Overall, our results show that the combined activity of PG endopeptidases and lytic transglycosylases is necessary for successful expansion of the cell wall during growth of a bacterium.
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Affiliation(s)
- Moneca Kaul
- CSIR-Centre for Cellular and Molecular Biology, Hyderabad, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India
| | - Suraj Kumar Meher
- CSIR-Centre for Cellular and Molecular Biology, Hyderabad, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India
| | - Krishna Chaitanya Nallamotu
- CSIR-Centre for Cellular and Molecular Biology, Hyderabad, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India
| | - Manjula Reddy
- CSIR-Centre for Cellular and Molecular Biology, Hyderabad, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India
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Santin YG, Cascales E. Measure of Peptidoglycan Degradation Activity. Methods Mol Biol 2024; 2715:197-205. [PMID: 37930529 DOI: 10.1007/978-1-0716-3445-5_12] [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] [Indexed: 11/07/2023]
Abstract
Most bacterial secretion systems are large machines that cross the cell envelope to deliver effectors outside the cell or directly into target cells. The peptidoglycan layer can therefore represent a physical barrier for the assembly of these large machines. Secretion systems and their counterparts such as type IV pili, flagella, and conjugation machines have therefore evolved or hijacked enzymes with peptidoglycan degradation activity. These enzymes are usually glycoside hydrolases that cleave the glycan chains of the peptidoglycan. Their activities are spatially controlled to avoid cell lysis and to create local rearrangement of the cell wall. In addition, peptidoglycan hydrolases may not be only required for the proper assembly of the secretion systems but may directly participate to the release of the effectors. Finally, several antibacterial effectors possess peptidoglycan degradation activity that damage the cell wall once delivered in the target cell. Here, we describe protocols to test the peptidoglycan degradation activity of these proteins in vitro and in solution.
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Affiliation(s)
- Yoann G Santin
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires, UMR7255, Institut de Microbiologie de la Méditerranée, Aix-Marseille Univ, CNRS, Marseille, France
- de Duve Institute, UCLouvain, Brussels, Belgium
| | - Eric Cascales
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires, UMR7255, Institut de Microbiologie de la Méditerranée, Aix-Marseille Univ, CNRS, Marseille, France.
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Soonthonsrima T, Htoo HH, Thiennimitr P, Srisuknimit V, Nonejuie P, Chaikeeratisak V. Phage-induced bacterial morphological changes reveal a phage-derived antimicrobial affecting cell wall integrity. Antimicrob Agents Chemother 2023; 67:e0076423. [PMID: 37843261 PMCID: PMC10648931 DOI: 10.1128/aac.00764-23] [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: 06/09/2023] [Accepted: 08/24/2023] [Indexed: 10/17/2023] Open
Abstract
In a looming post-antibiotic era, antibiotic alternatives have become key players in the combat against pathogens. Although recent advances in genomic research allow scientists to fully explore an organism's genome in the search for novel antibacterial molecules, laborious work is still needed in order to dissect each individual gene product for its antibacterial activity. Here, we exploited phage-induced bacterial morphological changes as anchors to explore and discover a potential phage-derived antimicrobial embedded in the phage genome. We found that, upon vibriophage KVP40 infection, Vibrio parahaemolyticus exhibited morphological changes similar to those observed when treated with mecillinam, a cell wall synthesis inhibitor, suggesting the mechanism of pre-killing that KVP40 exerts inside the bacterial cell upon sieging the host. Genome analysis revealed that, of all the annotated gene products in the KVP40 genome that are involved in cell wall degradation, lytic transglycosylase (LT) is of particular interest for subsequent functional studies. A single-cell morphological analysis revealed that heterologous expression of wild-type KVP40-LT induced similar bacterial morphological changes to those treated with the whole phage or mecillinam, prior to cell burst. On the contrary, neither the morphology nor the viability of the bacteria expressing signal-peptide truncated- or catalytic mutant E80A- KVP40-LT was affected, suggesting the necessity of these domains for the antibacterial activities. Altogether, this research paves the way for the future development of the discovery of phage-derived antimicrobials that is guided through phage-induced morphological changes.
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Affiliation(s)
- Tanapon Soonthonsrima
- Center of Excellence for Molecular Biology and Genomics of Shrimp, Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok, Thailand
- Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok, Thailand
| | - Htut Htut Htoo
- Institute of Molecular Biosciences, Mahidol University, Nakhon Pathom, Thailand
| | - Parameth Thiennimitr
- Department of Microbiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
- Research Center of Microbial Diversity and Sustainable Utilization, Chiang Mai University, Chiang Mai, Thailand
| | - Veerasak Srisuknimit
- Center of Excellence for Molecular Biology and Genomics of Shrimp, Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok, Thailand
- Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok, Thailand
| | - Poochit Nonejuie
- Institute of Molecular Biosciences, Mahidol University, Nakhon Pathom, Thailand
| | - Vorrapon Chaikeeratisak
- Center of Excellence for Molecular Biology and Genomics of Shrimp, Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok, Thailand
- Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok, Thailand
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9
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Zhang D, You F, He Y, Te SH, Gin KYH. Corrected and Republished from: "Isolation and Characterization of the First Freshwater Cyanophage Infecting Pseudanabaena". J Virol 2023; 97:e0040523. [PMID: 37074059 PMCID: PMC10286775 DOI: 10.1128/jvi.00405-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Accepted: 03/23/2023] [Indexed: 04/20/2023] Open
Abstract
Cyanobacteria are the major primary producers in both freshwater and marine environments. However, the majority of freshwater cyanophages remain unknown due to the limited number of cyanophage isolates. In this study, we present a novel lytic freshwater cyanophage, PA-SR01, which was isolated from the Singapore Serangoon Reservoir. To our knowledge, this is the first isolate of a cyanophage that has been found to infect the cyanobacterium Pseudanabaena. PA-SR01 has a narrow host range, a short latent period, and is chloroform sensitive. PA-SR01 is a member of Siphoviridae with a long noncontractile tail. It is a double-stranded DNA virus with a 137,012-bp genome. Functional annotation for the predicted open reading frames (ORFs) of the PA-SR01 genome identified genes with putative functions related to DNA metabolism, structural proteins, lysis, host-derived metabolic genes, and DNA packaging. Out of 166 predicted ORFs, only 17 ORFs have homology with genes with known function. Phylogenetic analysis of the major capsid protein and terminase large subunit further suggests that phage PA-SR01 is evolutionary distinct from known cyanophages. Metagenomics sequence recruitment onto the PA-SR01 genome indicates that PA-SR01 represents a new evolutionary lineage of phage which shares considerable genetic similarities with phage sequences in aquatic environments and could play key ecological roles. IMPORTANCE This study presents the isolation of the very first freshwater cyanophage, PA-SR01, that infects Pseudanabaena, and fills an important knowledge gap on freshwater cyanophages as well as cyanophages infecting Pseudanabaena.
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Affiliation(s)
- Dong Zhang
- NUS Environmental Research Institute, National University of Singapore, Singapore
| | - Fang You
- Department of Civil and Environmental Engineering, National University of Singapore, Singapore
| | - Yiliang He
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Shu Harn Te
- NUS Environmental Research Institute, National University of Singapore, Singapore
| | - Karina Yew-Hoong Gin
- NUS Environmental Research Institute, National University of Singapore, Singapore
- Department of Civil and Environmental Engineering, National University of Singapore, Singapore
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Dukes HE, Tinker KA, Ottesen EA. Disentangling hindgut metabolism in the American cockroach through single-cell genomics and metatranscriptomics. Front Microbiol 2023; 14:1156809. [PMID: 37323917 PMCID: PMC10266427 DOI: 10.3389/fmicb.2023.1156809] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Accepted: 05/08/2023] [Indexed: 06/17/2023] Open
Abstract
Omnivorous cockroaches host a complex hindgut microbiota comprised of insect-specific lineages related to those found in mammalian omnivores. Many of these organisms have few cultured representatives, thereby limiting our ability to infer the functional capabilities of these microbes. Here we present a unique reference set of 96 high-quality single cell-amplified genomes (SAGs) from bacterial and archaeal cockroach gut symbionts. We additionally generated cockroach hindgut metagenomic and metatranscriptomic sequence libraries and mapped them to our SAGs. By combining these datasets, we are able to perform an in-depth phylogenetic and functional analysis to evaluate the abundance and activities of the taxa in vivo. Recovered lineages include key genera within Bacteroidota, including polysaccharide-degrading taxa from the genera Bacteroides, Dysgonomonas, and Parabacteroides, as well as a group of unclassified insect-associated Bacteroidales. We also recovered a phylogenetically diverse set of Firmicutes exhibiting a wide range of metabolic capabilities, including-but not limited to-polysaccharide and polypeptide degradation. Other functional groups exhibiting high relative activity in the metatranscriptomic dataset include multiple putative sulfate reducers belonging to families in the Desulfobacterota phylum and two groups of methanogenic archaea. Together, this work provides a valuable reference set with new insights into the functional specializations of insect gut symbionts and frames future studies of cockroach hindgut metabolism.
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Affiliation(s)
- Helen E. Dukes
- Department of Microbiology, University of Georgia, Athens, GA, United States
| | - Kara A. Tinker
- National Energy Technology Laboratory (NETL), Pittsburgh, PA, United States
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11
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Alrafaie AM, Stafford GP. Enterococcal bacteriophage: A survey of the tail associated lysin landscape. Virus Res 2023; 327:199073. [PMID: 36787848 DOI: 10.1016/j.virusres.2023.199073] [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: 10/12/2022] [Revised: 02/05/2023] [Accepted: 02/10/2023] [Indexed: 02/16/2023]
Abstract
Bacteriophages are viruses that exclusively infect bacteria which require local degradation of cell barriers. This degradation is accomplished by various lysins located mainly within the phage tail structure. In this paper we surveyed and analysed the genomes of 506 isolated bacteriophage and prophage infecting or harboured within the genomes of the medically important Enterococcus faecalis and faecium. We highlight and characterise the major features of the genomes of phage in the morphological groups podovirus, siphovirus and myovirus, and explore their categorisation according to the new ICTV classifications, with a focus on putative extracellular lysins chiefly within tail modules. Our analysis reveals a range of potential cell-wall targeting enzyme domains that are part of tail, tape measure or other predicted base structures of these phages or prophages. These largely fall into protein domains targeting pentapeptide or glycosidic linkages within peptidoglycan but also potentially the enterococcal polysaccharide antigen (EPA) and wall teichoic acids of these species (i.e., Pectinesterases and Phosphodiesterases). Notably, there is a great variety of domain architectures that reveal the diversity of evolutionary solutions to attack the Enterococcus cell wall. Despite this variety, most phage and prophage possess a putative endopeptidase (70%), reflecting the ubiquity of this cell surface barrier. We also identified a predicted lytic transglycosylase domain belonging to the glycosyl hydrolase (GH) family 23 and present exclusively within tape measure proteins. Our data also reveal distinct features of the genomes of podo-, sipho- and myo-type viruses that most likely relate to their size and complexity. Overall, we lay a foundation for expression of recombinant TAL proteins and engineering of enterococcal and other phage that will be invaluable for researchers in this field.
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Affiliation(s)
- Alhassan M Alrafaie
- Integrated BioSciences, School of Clinical Dentistry, University of Sheffield, Sheffield, United Kingdom; Department of Medical Laboratory Sciences, College of Applied Medical Sciences in Al-Kharj, Prince Sattam Bin Abdulaziz University, Al-Kharj 11942, Saudi Arabia.
| | - Graham P Stafford
- Integrated BioSciences, School of Clinical Dentistry, University of Sheffield, Sheffield, United Kingdom.
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Kadhim BA, Alqaseer K, Al-Ganahi SA. Identification and characterization of a novel lytic peptidoglycan transglycosylase (MltC) in Shigella dysenteriae. Braz J Microbiol 2023:10.1007/s42770-023-00957-9. [PMID: 36973582 DOI: 10.1007/s42770-023-00957-9] [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: 11/14/2022] [Accepted: 03/20/2023] [Indexed: 03/29/2023] Open
Abstract
Shigellosis remains a worldwide health problem due to the lack of vaccines and the emergence of antibiotic-resistant strains. Shigella (S.) dysenteriae has rigid peptidoglycan (PG), and its tight regulation of biosynthesis and remodeling is essential for bacterial integrity. Lytic transglycosylases are highly conserved PG autolysins in bacteria that play essential roles in bacterial growth. However, their precise functions are obscure. We aimed to identify, clone, and express MltC, a unique autolysin in Escherichia (E.) coli C41 strain. The purification of recombinant MltC protein was performed using affinity chromatography and size-exclusion chromatography methods. The PG enzymatic activity of MltC was investigated using Zymogram and Fluorescein isothiocyanate (FITC)-labeled PG assays. Also, we aimed to detect its localization in bacterial fractions (cytoplasm and membrane) by western blot using specific polyclonal anti-MltC antibodies and its probable partners using immunoprecipitation and mass spectrometry applications. Purified MltC showed autolysin activity. Native MltC showed various locations in S. dysenteriae cells during different growth phases. In the Lag and early stationary phases, MltC was not found in cytoplasm and membrane fractions. However, it was detected in cytoplasm and membrane fractions during the exponential phase. In the late stationary phase, MltC was expressed in the membrane fraction only. Different candidate protein partners of MltC were identified that could be essential for bacterial growth and pathogenicity. This is the first study to suggest that MltC is indeed autolysin and could be a new drug target for the treatment of shigellosis by understanding its biological functions.
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Affiliation(s)
- Baleegh A Kadhim
- Department of Biology, College of Science, University of Al-Qadisiyah, Al Diwaniyah, Iraq.
| | - Kawther Alqaseer
- Department of Basic Science, College of Nursing, University of Kufa, Kufa, Iraq
| | - Sura A Al-Ganahi
- Department of Biology, College of Science, University of Al-Qadisiyah, Al Diwaniyah, Iraq
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13
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Weaver A, Taguchi A, Dörr T. Masters of Misdirection: Peptidoglycan Glycosidases in Bacterial Growth. J Bacteriol 2023; 205:e0042822. [PMID: 36757204 PMCID: PMC10029718 DOI: 10.1128/jb.00428-22] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2023] Open
Abstract
The dynamic composition of the peptidoglycan cell wall has been the subject of intense research for decades, yet how bacteria coordinate the synthesis of new peptidoglycan with the turnover and remodeling of existing peptidoglycan remains elusive. Diversity and redundancy within peptidoglycan synthases and peptidoglycan autolysins, enzymes that degrade peptidoglycan, have often made it challenging to assign physiological roles to individual enzymes and determine how those activities are regulated. For these reasons, peptidoglycan glycosidases, which cleave within the glycan strands of peptidoglycan, have proven veritable masters of misdirection over the years. Unlike many of the broadly conserved peptidoglycan synthetic complexes, diverse bacteria can employ unrelated glycosidases to achieve the same physiological outcome. Additionally, although the mechanisms of action for many individual enzymes have been characterized, apparent conserved homologs in other organisms can exhibit an entirely different biochemistry. This flexibility has been recently demonstrated in the context of three functions critical to vegetative growth: (i) release of newly synthesized peptidoglycan strands from their membrane anchors, (ii) processing of peptidoglycan turned over during cell wall expansion, and (iii) removal of peptidoglycan fragments that interfere with daughter cell separation during cell division. Finally, the regulation of glycosidase activity during these cell processes may be a cumulation of many factors, including protein-protein interactions, intrinsic substrate preferences, substrate availability, and subcellular localization. Understanding the true scope of peptidoglycan glycosidase activity will require the exploration of enzymes from diverse organisms with equally diverse growth and division strategies.
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Affiliation(s)
- Anna Weaver
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts, USA
| | - Atsushi Taguchi
- SANKEN (The Institute of Scientific and Industrial Research), Osaka University, Ibaraki, Osaka, Japan
| | - Tobias Dörr
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, New York, USA
- Department of Microbiology, Cornell University, Ithaca, New York, USA
- Cornell Institute of Host-Microbe Interactions and Disease, Cornell University, Ithaca, New York, USA
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14
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Liang Y, Zhao Y, Kwan J, Wang Y, Qiao Y. Escherichia coli has robust regulatory mechanisms against elevated peptidoglycan cleavage by lytic transglycosylases. J Biol Chem 2023; 299:104615. [PMID: 36931392 PMCID: PMC10139938 DOI: 10.1016/j.jbc.2023.104615] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 02/25/2023] [Accepted: 03/09/2023] [Indexed: 03/17/2023] Open
Abstract
Peptidoglycan (PG) is an essential and conserved exoskeletal component in all bacteria that protects cells from lysis. Gram-negative bacteria such as Escherichia coli encode multiple redundant lytic transglycosylases (LTs) that engage in PG cleavage, a potentially lethal activity requiring proper regulation to prevent autolysis. To elucidate the potential effects and cellular regulatory mechanisms of elevated LT activity, we individually cloned the periplasmic domains of two membrane-bound LTs, MltA and MltB under the control of the arabinose-inducible system for overexpression in the periplasmic space in E. coli. Interestingly, upon induction, the culture undergoes an initial period of cell lysis followed by robust growth restoration. The LT-overexpressing E. coli exhibits altered morphology with larger spherical cells, which is in line with the weakening of the PG layer due to aberrant LT activity. On the other hand, the restored cells display a similar rod shape and peptidoglycan profile that is indistinguishable from the uninduced control. Quantitative proteomics analysis of the restored cells identified significant protein enrichment in the regulator of capsule synthesis (Rcs) regulon, a two-component stress response known to be specifically activated by PG damage. We showed that LT-overexpressing E. coli with an inactivated Rcs system partially impairs the growth restoration process, supporting the involvement of the Rcs system in countering aberrant PG cleavage. Furthermore, we demonstrated that the elevated LT activity specifically potentiates β-lactam antibiotics against E. coli with a defective Rcs regulon, suggesting the dual effects of augmented PG cleavage and blocked PG synthesis as a potential antimicrobial strategy.
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Affiliation(s)
- Yaquan Liang
- School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technical University, Singapore 637371
| | - Yilin Zhao
- School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technical University, Singapore 637371
| | - JericMunChung Kwan
- School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technical University, Singapore 637371
| | - Yue Wang
- A*STAR Infectious Disease Labs, Singapore 138648
| | - Yuan Qiao
- School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technical University, Singapore 637371.
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15
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Chen C, Chen S, Wang B. A glance at the gut microbiota and the functional roles of the microbes based on marmot fecal samples. Front Microbiol 2023; 14:1035944. [PMID: 37125200 PMCID: PMC10140447 DOI: 10.3389/fmicb.2023.1035944] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Accepted: 03/13/2023] [Indexed: 05/02/2023] Open
Abstract
Research on the gut microbiota, which involves a large and complex microbial community, is an important part of infectious disease control. In China, few studies have been reported on the diversity of the gut microbiota of wild marmots. To obtain full details of the gut microbiota, including bacteria, fungi, viruses and archaea, in wild marmots, we have sequenced metagenomes from five sample-sites feces on the Hulun Buir Grassland in Inner Mongolia, China. We have created a comprehensive database of bacterial, fungal, viral, and archaeal genomes and aligned metagenomic sequences (determined based on marmot fecal samples) against the database. We delineated the detailed and distinct gut microbiota structures of marmots. A total of 5,891 bacteria, 233 viruses, 236 fungi, and 217 archaea were found. The dominant bacterial phyla were Firmicutes, Proteobacteria, Bacteroidetes, and Actinomycetes. The viral families were Myoviridae, Siphoviridae, Phycodnaviridae, Herpesviridae and Podoviridae. The dominant fungi phyla were Ascomycota, Basidiomycota, and Blastocladiomycota. The dominant archaea were Biobacteria, Omoarchaea, Nanoarchaea, and Microbacteria. Furthermore, the gut microbiota was affected by host species and environment, and environment was the most important factor. There were 36,989 glycoside hydrolase genes in the microbiota, with 365 genes homologous to genes encoding β-glucosidase, cellulase, and cellulose β-1,4-cellobiosidase. Additionally, antibiotic resistance genes such as macB, bcrA, and msbA were abundant. To sum up, the gut microbiota of marmot had population diversity and functional diversity, which provides a basis for further research on the regulatory effects of the gut microbiota on the host. In addition, metagenomics revealed that the gut microbiota of marmots can degrade cellulose and hemicellulose.
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Affiliation(s)
- Chuizhe Chen
- Department of Pathology, Hainan General Hospital, Hainan Affiliated Hospital of Hainan Medical University, Haikou, China
- Key Laboratory of Tropical Translational Medicine of Ministry of Education, NHC Key Laboratory of Tropical Disease Control, School of Tropical Medicine and the Second Affiliated Hospital, Hainan Medical University, Haikou, China
| | - Shu Chen
- Medical Laboratory Center, Hainan General Hospital, Hainan Affiliated Hospital of Hainan Medical University, Haikou, China
| | - Bo Wang
- Department of Pathology, Hainan General Hospital, Hainan Affiliated Hospital of Hainan Medical University, Haikou, China
- *Correspondence: Bo Wang,
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16
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Ghods S, Moradali MF, Duryea D, Walker AR, Davey ME. Growth of Porphyromonas gingivalis on human serum albumin triggers programmed cell death. J Oral Microbiol 2022; 15:2161182. [PMID: 36570975 PMCID: PMC9788703 DOI: 10.1080/20002297.2022.2161182] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Aims Gingival crevicular fluid (GCF) constitutes the primary growth substrate for Porphyromonas gingivalis in vivo. The goal of this work was to evaluate the growth of different strains of P. gingivalis on human serum albumin (HSA), a major constituent of GCF. Methods Growth of five different strains of P. gingivalis in the HSA medium was examined and, surprisingly, three of the strains underwent autolysis within 24 h. Comparative transcriptomic analysis was used to identify genes involved in autolysis. Results Two highly related reference strains (W50 and W83) differed dramatically in their survival when grown on HSA. Strain W83 grew fast and lysed within 24 h, while W50 survived for an additional 20 h. Differential gene expression analysis led us to a gene cluster containing enzymes involved in arginine metabolism and a gene predicted to be lytic murein transglycosylase, which are known to play a role in autolysis. Deletion of this gene (PG0139) resulted in a mutant that did not lyse, and complementation restored the HSA lysis phenotype, indicating that this enzyme plays a central role in the autolysis of P. gingivalis. Conclusions P. gingivalis undergoes autolysis when provided with HSA as a substrate for growth.
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Affiliation(s)
| | | | | | | | - Mary E. Davey
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, FL, USA,CONTACT Mary E. Davey The Forsyth Institute, Cambridge, MA02142, USA
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17
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Martinez-Bond EA, Soriano BM, Williams AH. The mechanistic landscape of Lytic transglycosylase as targets for antibacterial therapy. Curr Opin Struct Biol 2022; 77:102480. [PMID: 36323133 DOI: 10.1016/j.sbi.2022.102480] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 08/24/2022] [Accepted: 09/09/2022] [Indexed: 12/14/2022]
Abstract
Lytic transglycosylases (Ltgs) are glycan strand cleaving enzymes whose role is poorly understood in the genesis of the bacterial envelope. They play multiple roles in all stages of a bacterial life cycle, by creating holes in the peptidoglycan that is necessary for cell division and separation. Here, we review recent advances in understanding the suitability of Ltgs as antibacterial drug targets. We specifically highlight a known inhibitor bulgecin A that is able to inhibit the function of structurally diverse Ltgs, as well as synergize with beta-lactams to improve its efficacy in antibiotic insensitive strains. Discovery of new antibiotics or new targets has been challenging. These studies could provide a viable path toward designing broad-spectrum inhibitors that targets Ltgs.
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Affiliation(s)
- Elizabeth A Martinez-Bond
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, CA, 94158, USA. https://twitter.com/bondlizbond
| | - Berliza M Soriano
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, CA, 94158, USA. https://twitter.com/AWilliamslab
| | - Allison H Williams
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, CA, 94158, USA; Chan Zuckerberg Biohub, San Francisco, CA, USA.
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18
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The Discovery of the Role of Outer Membrane Vesicles against Bacteria. Biomedicines 2022; 10:biomedicines10102399. [PMID: 36289660 PMCID: PMC9598313 DOI: 10.3390/biomedicines10102399] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 09/02/2022] [Accepted: 09/22/2022] [Indexed: 11/23/2022] Open
Abstract
Gram-negative bacteria are intrinsically resistant to many commercialized antibiotics. The outer membrane (OM) of Gram-negative bacteria prevents the entry of such antibiotics. Outer membrane vesicles (OMV) are naturally released from the OM of Gram-negative bacteria for a range of purposes, including competition with other bacteria. OMV may carry, as part of the membrane or lumen, molecules with antibacterial activity. Such OMV can be exposed to and can fuse with the cell surface of different bacterial species. In this review we consider how OMV can be used as tools to deliver antimicrobial agents. This includes the characteristics of OMV production and how this process can be used to create the desired antibacterial activity of OMV.
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19
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Exploitation of a Bacterium-Encoded Lytic Transglycosylase by a Human Oral Lytic Phage To Facilitate Infection. J Virol 2022; 96:e0106322. [PMID: 36000841 PMCID: PMC9472602 DOI: 10.1128/jvi.01063-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Bacteriophages (phages) are an integral part of the human oral microbiome. Their roles in modulating bacterial physiology and shaping microbial communities have been discussed but remain understudied due to limited isolation and characterization of oral phage. Here, we report the isolation of LC001, a lytic phage targeting human oral Schaalia odontolytica (formerly known as Actinomyces odontolyticus) strain XH001. We showed that LC001 attached to and infected surface-grown, but not planktonic, XH001 cells, and it displayed remarkable host specificity at the strain level. Whole-genome sequencing of spontaneous LC001-resistant, surface-grown XH001 mutants revealed that the majority of the mutants carry nonsense or frameshift mutations in XH001 gene APY09_05145 (renamed ltg-1), which encodes a putative lytic transglycosylase (LT). The mutants are defective in LC001 binding, as revealed by direct visualization of the significantly reduced attachment of phage particles to the XH001 spontaneous mutants compared that to the wild type. Meanwhile, targeted deletion of ltg-1 produced a mutant that is defective in LC001 binding and resistant to LC001 infection even as surface-grown cells, while complementation of ltg-1 in the mutant background restored the LC001-sensitive phenotype. Intriguingly, similar expression levels of ltg-1 were observed in surface-grown and planktonic XH001, which displayed LC001-binding and nonbinding phenotypes, respectively. Furthermore, the overexpression of ltg-1 failed to confer an LC001-binding and -sensitive phenotype to planktonic XH001. Thus, our data suggested that rather than directly serving as a phage receptor, ltg-1-encoded LT may increase the accessibility of phage receptor, possibly via its enzymatic activity, by cleaving the peptidoglycan structure for better receptor exposure during peptidoglycan remodeling, a function that can be exploited by LC001 to facilitate infection. IMPORTANCE The evidence for the presence of a diverse and abundant phage population in the host-associated oral microbiome came largely from metagenomic analysis or the observation of virus-like particles within saliva/plaque samples, while the isolation of oral phage and investigation of their interaction with bacterial hosts are limited. Here, we report the isolation of LC001, the first lytic phage targeting oral Schaalia odontolytica. Our study suggested that LC001 may exploit the host bacterium-encoded lytic transglycosylase function to gain access to the receptor, thus facilitating its infection.
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20
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de Freitas LS, Queiroz MAF, Machado LFA, Vallinoto ACR, Ishak MDOG, Santos FDAA, Goulart LR, Ishak R. Bioprospecting by Phage Display of Mimetic Peptides of Chlamydia trachomatis for Use in Laboratory Diagnosis. Infect Drug Resist 2022; 15:4935-4945. [PMID: 36065279 PMCID: PMC9440705 DOI: 10.2147/idr.s369339] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Accepted: 06/15/2022] [Indexed: 11/23/2022] Open
Abstract
Background Chlamydia trachomatis infection is a major public health problem and the most common sexually transmitted infection in the world. Although highly prevalent, 70% to 80% of cases are asymptomatic and undiagnosed. Purpose To overcome some limitations in terms of rapid diagnosis, phage display technology was used to bioprospect peptide mimetics of C. trachomatis immunoreactive and immunogenic antigens to be selected for the production of synthetic peptides. Methods Initially, IgG from 22 individuals with C. trachomatis and 30 negative controls was coupled to G protein magnetic beads. The phage display technique consisted of biopanning, genetic sequencing, bioinformatics analysis and phage ELISA. Results Clones G1, H5, C6 and H7 were selected for testing with individual samples positive and negative for C. trachomatis. Reactions were statistically significant (p < 0.05), with a sensitivity of 90.91, a specificity of 54.55, and AUC values >0.8. One-dimensional analysis with C. trachomatis components indicated that the G1 clone aligned with cell wall-associated hydrolase domain-containing protein, the H5 clone aligned with glycerol-3-phosphate acyltransferase PlsX protein, the C6 clone aligned with a transposase and inactivated derivatives, and the H7 clone aligned with GTP-binding protein. Molecular modeling and three-dimensional analysis indicated the best fit of the four clones with a protein known as chlamydial protease/proteasome-like activity factor (CPAF), an important virulence factor of the bacterium. Conclusion The peptides produced by phage display are related to the metabolic pathways of C. trachomatis, indicating that they can be used to understand the pathogenesis of the infection. Because of their high sensitivity and AUC values, the peptides present considerable potential for use in platforms for screening C. trachomatis infections.
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Affiliation(s)
- Larissa Silva de Freitas
- Laboratory of Virology, Biological Sciences Institute, Federal University of Pará, Belém, Pará, Brazil
| | - Maria Alice Freitas Queiroz
- Laboratory of Virology, Biological Sciences Institute, Federal University of Pará, Belém, Pará, Brazil
- Correspondence: Maria Alice Freitas Queiroz, Laboratory of Virology, Biological Sciences Institute, Federal University of Pará, Belém, Pará, Brazil, Tel +55 91 3201-7587, Email
| | | | | | | | - Fabiana de Almeida Araújo Santos
- Laboratory of Nanobiotechnology, Genetics and Biochemistry Institute, Federal University of Uberlândia, Uberlândia, Minas Gerais, Brazil
| | - Luiz Ricardo Goulart
- Laboratory of Nanobiotechnology, Genetics and Biochemistry Institute, Federal University of Uberlândia, Uberlândia, Minas Gerais, Brazil
| | - Ricardo Ishak
- Laboratory of Virology, Biological Sciences Institute, Federal University of Pará, Belém, Pará, Brazil
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21
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Wang M, Buist G, van Dijl JM. Staphylococcus aureus cell wall maintenance - the multifaceted roles of peptidoglycan hydrolases in bacterial growth, fitness, and virulence. FEMS Microbiol Rev 2022; 46:6604383. [PMID: 35675307 PMCID: PMC9616470 DOI: 10.1093/femsre/fuac025] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 04/22/2022] [Accepted: 05/25/2022] [Indexed: 01/07/2023] Open
Abstract
Staphylococcus aureus is an important human and livestock pathogen that is well-protected against environmental insults by a thick cell wall. Accordingly, the wall is a major target of present-day antimicrobial therapy. Unfortunately, S. aureus has mastered the art of antimicrobial resistance, as underscored by the global spread of methicillin-resistant S. aureus (MRSA). The major cell wall component is peptidoglycan. Importantly, the peptidoglycan network is not only vital for cell wall function, but it also represents a bacterial Achilles' heel. In particular, this network is continuously opened by no less than 18 different peptidoglycan hydrolases (PGHs) encoded by the S. aureus core genome, which facilitate bacterial growth and division. This focuses attention on the specific functions executed by these enzymes, their subcellular localization, their control at the transcriptional and post-transcriptional levels, their contributions to staphylococcal virulence and their overall importance in bacterial homeostasis. As highlighted in the present review, our understanding of the different aspects of PGH function in S. aureus has been substantially increased over recent years. This is important because it opens up new possibilities to exploit PGHs as innovative targets for next-generation antimicrobials, passive or active immunization strategies, or even to engineer them into effective antimicrobial agents.
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Affiliation(s)
- Min Wang
- Department of Medical Microbiology, University of Groningen, University Medical Center Groningen, Hanzeplein 1, PO Box 30001, 9700 RB Groningen, the Netherlands
| | | | - Jan Maarten van Dijl
- Corresponding author: Department of Medical Microbiology, University of Groningen, University Medical Center Groningen, Hanzeplein 1, P.O. box 30001, HPC EB80, 9700 RB Groningen, the Netherlands, Tel. +31-50-3615187; Fax. +31-50-3619105; E-mail:
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22
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Mojica MF, Humphries R, Lipuma JJ, Mathers AJ, Rao GG, Shelburne SA, Fouts DE, Van Duin D, Bonomo RA. Clinical challenges treating Stenotrophomonas maltophilia infections: an update. JAC Antimicrob Resist 2022; 4:dlac040. [PMID: 35529051 PMCID: PMC9071536 DOI: 10.1093/jacamr/dlac040] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/30/2023] Open
Abstract
Stenotrophomonas maltophilia is a non-fermenting, Gram-negative bacillus that has emerged as an opportunistic nosocomial pathogen. Its intrinsic multidrug resistance makes treating infections caused by S. maltophilia a great clinical challenge. Clinical management is further complicated by its molecular heterogeneity that is reflected in the uneven distribution of antibiotic resistance and virulence determinants among different strains, the shortcomings of available antimicrobial susceptibility tests and the lack of standardized breakpoints for the handful of antibiotics with in vitro activity against this microorganism. Herein, we provide an update on the most recent literature concerning these issues, emphasizing the impact they have on clinical management of S. maltophilia infections.
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Affiliation(s)
- Maria F. Mojica
- Department of Molecular Biology and Microbiology, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
- Case Western Reserve University-Cleveland VA Medical Center for Antimicrobial Resistance and Epidemiology (Case VA CARES), Cleveland, OH, USA
- Research Service, VA Northeast Ohio Healthcare System, Cleveland, OH, USA
- Grupo de Resistencia Antimicrobiana y Epidemiología Hospitalaria, Universidad El Bosque, Bogotá, Colombia
| | - Romney Humphries
- Department of Pathology, Immunology and Microbiology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - John J. Lipuma
- University of Michigan Medical School, Pediatric Infectious Disease, Ann Arbor, MI, USA
| | - Amy J. Mathers
- Division of Infectious Disease and International Health, Department of Medicine, University of Virginia Health System, Charlottesville, VA, USA
- Clinical Microbiology Laboratory, Department of Pathology, University of Virginia Health System, Charlottesville, VA, USA
| | - Gauri G. Rao
- Division of Pharmacotherapy and Experimental Therapeutics, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Samuel A. Shelburne
- Department of Infectious Diseases Infection Control and Employee Health, University of Texas MD Anderson Cancer Center, Houston, TX, USA
- Department of Genomic Medicine, University of Texas MD Anderson Cancer Center, Houston, TX, USA
- Center for Antimicrobial Resistance and Microbial Genomics, University of Texas Health Science Center McGovern Medical School, Houston, TX, USA
| | - Derrick E. Fouts
- Genomic Medicine, The J. Craig Venter Institute, Rockville, MD, USA
| | - David Van Duin
- Department of Medicine, University of North Carolina School of Medicine, Chapel Hill, NC, USA
| | - Robert A. Bonomo
- Case Western Reserve University-Cleveland VA Medical Center for Antimicrobial Resistance and Epidemiology (Case VA CARES), Cleveland, OH, USA
- Research Service, VA Northeast Ohio Healthcare System, Cleveland, OH, USA
- Senior Clinician Scientist Investigator, Veterans Affairs Northeast Ohio Healthcare System, Cleveland, OH, USA
- Medical Service and Geriatric Research, Education, and Clinical Center (GRECC), Veterans Affairs Northeast Ohio Healthcare System, Cleveland, OH, USA
- Departments of Medicine, Biochemistry, Pharmacology, Molecular Biology and Microbiology, and Proteomics and Bioinformatics, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
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23
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Zhang Y, Chen W, Wu D, Liu Y, Wu Z, Li J, Zhang SY, Ji Q. Molecular basis for cell-wall recycling regulation by transcriptional repressor MurR in Escherichia coli. Nucleic Acids Res 2022; 50:5948-5960. [PMID: 35640608 PMCID: PMC9177960 DOI: 10.1093/nar/gkac442] [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: 01/11/2022] [Revised: 05/01/2022] [Accepted: 05/10/2022] [Indexed: 11/13/2022] Open
Abstract
The cell-wall recycling process is important for bacterial survival in nutrient-limited conditions and, in certain cases, is directly involved in antibiotic resistance. In the sophisticated cell-wall recycling process in Escherichia coli, the transcriptional repressor MurR controls the expression of murP and murQ, which are involved in transporting and metabolizing N-acetylmuramic acid (MurNAc), generating N-acetylmuramic acid-6-phosphate (MurNAc-6-P) and N-acetylglucosamine-6-phosphate (GlcNAc-6-P). Here, we report that both MurNAc-6-P and GlcNAc-6-P can bind to MurR and weaken the DNA binding ability of MurR. Structural characterizations of MurR in complex with MurNAc-6-P or GlcNAc-6-P as well as in the apo form revealed the detailed ligand recognition chemistries. Further studies showed that only MurNAc-6-P, but not GlcNAc-6-P, is capable of derepressing the expression of murQP controlled by MurR in cells and clarified the substrate specificity through the identification of key residues responsible for ligand binding in the complex structures. In summary, this study deciphered the molecular mechanism of the cell wall recycling process regulated by MurR in E. coli.
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Affiliation(s)
- Ya Zhang
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Weizhong Chen
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Di Wu
- Shanghai Key Laboratory for Molecular Engineer of Chiral Drugs, School of Chemistry and Chemical Engineering & Frontiers Science Center for Transformative Molecules, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Yushi Liu
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Zhaowei Wu
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Jian Li
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Shu-Yu Zhang
- Shanghai Key Laboratory for Molecular Engineer of Chiral Drugs, School of Chemistry and Chemical Engineering & Frontiers Science Center for Transformative Molecules, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Quanjiang Ji
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China.,Gene Editing Center, School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
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Scaffolding Protein GspB/OutB Facilitates Assembly of the Dickeya dadantii Type 2 Secretion System by Anchoring the Outer Membrane Secretin Pore to the Inner Membrane and to the Peptidoglycan Cell Wall. mBio 2022; 13:e0025322. [PMID: 35546537 PMCID: PMC9239104 DOI: 10.1128/mbio.00253-22] [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: 11/24/2022] Open
Abstract
The phytopathogenic proteobacterium Dickeya dadantii secretes an array of plant cell wall-degrading enzymes and other virulence factors via the type 2 secretion system (T2SS). T2SSs are widespread among important plant, animal, and human bacterial pathogens. This multiprotein complex spans the double membrane cell envelope and secretes fully folded proteins through a large outer membrane pore formed by 15 subunits of the secretin GspD. Secretins are also found in the type 3 secretion system and the type 4 pili. Usually, specialized lipoproteins termed pilotins assist the targeting and assembly of secretins into the outer membrane. Here, we show that in D. dadantii, the pilotin acts in concert with the scaffolding protein GspB. Deletion of gspB profoundly impacts secretin assembly, pectinase secretion, and virulence. Structural studies reveal that GspB possesses a conserved periplasmic homology region domain that interacts directly with the N-terminal secretin domain. Site-specific photo-cross-linking unravels molecular details of the GspB-GspD complex in vivo. We show that GspB facilitates outer membrane targeting and assembly of the secretin pores and anchors them to the inner membrane while the C-terminal extension of GspB provides a scaffold for the secretin channel in the peptidoglycan cell wall. Phylogenetic analysis shows that in other bacteria, GspB homologs vary in length and domain composition and act in concert with either a cognate ATPase GspA or the pilotin GspS.
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de Oliveira ACP, Ferreira RM, Ferro MIT, Ferro JA, Zamuner C, Ferreira H, Varani AM. XAC4296 Is a Multifunctional and Exclusive Xanthomonadaceae Gene Containing a Fusion of Lytic Transglycosylase and Epimerase Domains. Microorganisms 2022; 10:1008. [PMID: 35630451 PMCID: PMC9143381 DOI: 10.3390/microorganisms10051008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Revised: 04/29/2022] [Accepted: 05/09/2022] [Indexed: 02/05/2023] Open
Abstract
Microorganisms have a limited and highly adaptable repertoire of genes capable of encoding proteins containing single or variable multidomains. The phytopathogenic bacteria Xanthomonas citri subsp. citri (X. citri) (Xanthomonadaceae family), the etiological agent of Citrus Canker (CC), presents a collection of multidomain and multifunctional enzymes (MFEs) that remains to be explored. Recent studies have shown that multidomain enzymes that act on the metabolism of the peptidoglycan and bacterial cell wall, belonging to the Lytic Transglycosylases (LTs) superfamily, play an essential role in X. citri biology. One of these LTs, named XAC4296, apart from the Transglycosylase SLT_2 and Peptidoglycan binding-like domains, contains an unexpected aldose 1-epimerase domain linked to the central metabolism; therefore, resembling a canonical MFE. In this work, we experimentally characterized XAC4296 revealing its role as an MFE and demonstrating its probable gene fusion origin and evolutionary history. The XAC4296 is expressed during plant-pathogen interaction, and the Δ4296 mutant impacts CC progression. Moreover, Δ4296 exhibited chromosome segregation and cell division errors, and sensitivity to ampicillin, suggesting not only LT activity but also that the XAC4296 may also contribute to resistance to β-lactams. However, both Δ4296 phenotypes can be restored when the mutant is supplemented with sucrose or glutamic acid as a carbon and nitrogen source, respectively; therefore, supporting the epimerase domain's functional relationship with the central carbon and cell wall metabolism. Taken together, these results elucidate the role of XAC4296 as an MFE in X. citri, also bringing new insights into the evolution of multidomain proteins and antimicrobial resistance in the Xanthomonadaceae family.
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Affiliation(s)
- Amanda C. P. de Oliveira
- Graduate Program in Agricultural and Livestock Microbiology, School of Agricultural and Veterinary Sciences, São Paulo State University (UNESP), Jaboticabal 14884-900, SP, Brazil;
- Department of Agricultural and Environmental Biotechnology, School of Agricultural and Veterinary Sciences, São Paulo State University (UNESP), Jaboticabal 14884-900, SP, Brazil; (R.M.F.); (M.I.T.F.); (J.A.F.)
| | - Rafael M. Ferreira
- Department of Agricultural and Environmental Biotechnology, School of Agricultural and Veterinary Sciences, São Paulo State University (UNESP), Jaboticabal 14884-900, SP, Brazil; (R.M.F.); (M.I.T.F.); (J.A.F.)
- Graduate Program in Genetics and Plant Breeding, School of Agricultural and Veterinary Sciences, São Paulo State University (UNESP), Jaboticabal 14884-900, SP, Brazil
| | - Maria Inês T. Ferro
- Department of Agricultural and Environmental Biotechnology, School of Agricultural and Veterinary Sciences, São Paulo State University (UNESP), Jaboticabal 14884-900, SP, Brazil; (R.M.F.); (M.I.T.F.); (J.A.F.)
| | - Jesus A. Ferro
- Department of Agricultural and Environmental Biotechnology, School of Agricultural and Veterinary Sciences, São Paulo State University (UNESP), Jaboticabal 14884-900, SP, Brazil; (R.M.F.); (M.I.T.F.); (J.A.F.)
| | - Caio Zamuner
- Department of General and Applied Biology, Institute of Biosciences, São Paulo State University (UNESP), Rio Claro 13506-900, SP, Brazil; (C.Z.); (H.F.)
| | - Henrique Ferreira
- Department of General and Applied Biology, Institute of Biosciences, São Paulo State University (UNESP), Rio Claro 13506-900, SP, Brazil; (C.Z.); (H.F.)
| | - Alessandro M. Varani
- Department of Agricultural and Environmental Biotechnology, School of Agricultural and Veterinary Sciences, São Paulo State University (UNESP), Jaboticabal 14884-900, SP, Brazil; (R.M.F.); (M.I.T.F.); (J.A.F.)
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Li Q, Zhou Y, Lu R, Zheng P, Wang Y. Phylogeny, distribution and potential metabolism of candidate bacterial phylum KSB1. PeerJ 2022; 10:e13241. [PMID: 35433121 PMCID: PMC9012183 DOI: 10.7717/peerj.13241] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Accepted: 03/18/2022] [Indexed: 01/13/2023] Open
Abstract
Candidate phylum KSB1 is composed of uncultured bacteria and has been reported across various environments. However, the phylogeny and metabolic potential of KSB1 have not been studied comprehensively. In this study, phylogenomic analysis of KSB1 genomes from public databases and eleven metagenome-assembled genomes (MAGs) from marine and hydrothermal sediments revealed that those genomes were clustered into four clades. Isolation source and relative abundance of KSB1 genomes showed that clade I was particularly abundant in bioreactor sludge. Genes related to dissimilatory reduction of nitrate to ammonia (DNRA), the last step of denitrification converting nitrous oxide to nitrogen and assimilatory sulfur reduction were observed in the expanded genomes of clade I, which may due to horizontal gene transfer that frequently occurred in bioreactor. Annotation and metabolic reconstruction of clades II and IV showed flagellum assembly and chemotaxis genes in the genomes, which may indicate that exploration and sensing for nutrients and chemical gradients are critical for the two clades in deep-sea and hydrothermal sediment. Metabolic potentials of fatty acids and short-chain hydrocarbons utilization were predicted in clades I and IV of KSB1. Collectively, phylogenomic and metabolic analyses of KSB1 clades provide insight into their anaerobic heterotrophic lifestyle and differentiation in potential ecological roles.
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Affiliation(s)
- Qingmei Li
- Institute of Deep Sea Science and Engineering, Chinese Academy of Sciences, Sanya, China,University of Chinese Academy of Sciences, Beijing, China
| | - Yingli Zhou
- Institute of Deep Sea Science and Engineering, Chinese Academy of Sciences, Sanya, China,University of Chinese Academy of Sciences, Beijing, China
| | - Rui Lu
- Institute of Deep Sea Science and Engineering, Chinese Academy of Sciences, Sanya, China,University of Chinese Academy of Sciences, Beijing, China
| | - Pengfei Zheng
- Institute of Deep Sea Science and Engineering, Chinese Academy of Sciences, Sanya, China
| | - Yong Wang
- Institute of Deep Sea Science and Engineering, Chinese Academy of Sciences, Sanya, China,Institute for Marine Engineering, Shenzhen International Graduate School, Tsinghua University, Shenzhen, China
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Zhu R, Mathur V. Prophages Present in Acinetobacter pittii Influence Bacterial Virulence, Antibiotic Resistance, and Genomic Rearrangements. PHAGE (NEW ROCHELLE, N.Y.) 2022; 3:38-49. [PMID: 36161193 PMCID: PMC9041518 DOI: 10.1089/phage.2021.0014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Introduction: Antibiotic resistance and virulence are common among bacterial populations, posing a global clinical challenge. The bacterial species Acinetobacter pittii, an infectious agent in clinical environments, has shown increasing rates of antibiotic resistance. Viruses that integrate as prophages into A. pittii could be a potential cause of this pathogenicity, as they often contain antibiotic resistance or virulence factor gene sequences. Methods: In this study, we analyzed 25 A. pittii strains for potential prophages. Using virulence factor databases, we identified many common and virulent prophages in A. pittii. Results: The analysis also included a specific catalogue of the virulence factors and antibiotic resistance genes contributed by A. pittii prophages. Finally, our results illustrate multiple similarities between A. pittii and its bacterial relatives with regard to prophage integration sites and prevalence. Discussion: These findings provide a broader insight into prophage behavior that can be applied to future studies on similar species in the Acinetobacter calcoaceticus-baumannii complex.
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Affiliation(s)
| | - Vinayak Mathur
- Department of Science, Cabrini University, Radnor, Pennsylvania, USA.,Address correspondence to: Vinayak Mathur, PhD, Department of Science, Cabrini University, 610 King of Prussia Road, IAD 224, Radnor, PA 19087-3698, USA
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Structural basis for effector recognition by an antibacterial type IV secretion system. Proc Natl Acad Sci U S A 2022; 119:2112529119. [PMID: 34983846 PMCID: PMC8740702 DOI: 10.1073/pnas.2112529119] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/19/2021] [Indexed: 11/19/2022] Open
Abstract
Type IV secretion systems (T4SSs) have been studied for more than 70 y because of their roles in mediating horizontal DNA transfer, responsible for the spread of antibiotic resistance, and the injection of virulence factors into animal and plant hosts. Another important function is the contact-dependent injection of toxic effectors into competing bacteria of different species during bacterial warfare. The present study reveals how T4SSs use a specific domain of the VirD4 coupling protein to recruit antibacterial toxins for secretion by recognizing conserved carboxyl-terminal secretion signal domains. The molecular structure of the secretion signal domain described in this work will serve as a model for thousands of homologs encountered in several hundred distinct bacterial species. Many soil-, water-, and plant-associated bacterial species from the orders Xanthomonadales, Burkholderales, and Neisseriales carry a type IV secretion system (T4SS) specialized in translocating effector proteins into other gram-negative species, leading to target cell death. These effectors, known as X-Tfes, carry a carboxyl-terminal domain of ∼120 residues, termed XVIPCD, characterized by several conserved motifs and a glutamine-rich tail. Previous studies showed that the XVIPCD is required for interaction with the T4SS coupling protein VirD4 and for T4SS-dependent translocation. However, the structural basis of the XVIPCD–VirD4 interaction is unknown. Here, we show that the XVIPCD interacts with the central all-alpha domain of VirD4 (VirD4AAD). We used solution NMR spectroscopy to solve the structure of the XVIPCD of X-TfeXAC2609 from Xanthomonas citri and to map its interaction surface with VirD4AAD. Isothermal titration calorimetry and in vivo Xanthomonas citri versus Escherichia coli competition assays using wild-type and mutant X-TfeXAC2609 and X-TfeXAC3634 indicate that XVIPCDs can be divided into two regions with distinct functions: the well-folded N-terminal region contains specific conserved motifs that are responsible for interactions with VirD4AAD, while both N- and carboxyl-terminal regions are required for effective X-Tfe translocation into the target cell. The conformational stability of the N-terminal region is reduced at and below pH 7.0, a property that may facilitate X-Tfe unfolding and translocation through the more acidic environment of the periplasm.
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Suzuki S, Kawachi M, Tsukakoshi C, Nakamura A, Hagino K, Inouye I, Ishida KI. Unstable Relationship Between Braarudosphaera bigelowii (= Chrysochromulina parkeae) and Its Nitrogen-Fixing Endosymbiont. FRONTIERS IN PLANT SCIENCE 2021; 12:749895. [PMID: 34925404 PMCID: PMC8679911 DOI: 10.3389/fpls.2021.749895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Accepted: 11/10/2021] [Indexed: 06/14/2023]
Abstract
Marine phytoplankton are major primary producers, and their growth is primarily limited by nitrogen in the oligotrophic ocean environment. The haptophyte Braarudosphaera bigelowii possesses a cyanobacterial endosymbiont (UCYN-A), which plays a major role in nitrogen fixation in the ocean. However, host-symbiont interactions are poorly understood because B. bigelowii was unculturable. In this study, we sequenced the complete genome of the B. bigelowii endosymbiont and showed that it was highly reductive and closely related to UCYN-A2 (an ecotype of UCYN-A). We succeeded in establishing B. bigelowii strains and performed microscopic observations. The detailed observations showed that the cyanobacterial endosymbiont was surrounded by a single host derived membrane and divided synchronously with the host cell division. The transcriptome of B. bigelowii revealed that B. bigelowii lacked the expression of many essential genes associated with the uptake of most nitrogen compounds, except ammonia. During cultivation, some of the strains completely lost the endosymbiont. Moreover, we did not find any evidence of endosymbiotic gene transfer from the endosymbiont to the host. These findings illustrate an unstable morphological, metabolic, and genetic relationship between B. bigelowii and its endosymbiont.
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Affiliation(s)
- Shigekatsu Suzuki
- Biodiversity Division, National Institute for Environmental Studies, Ibaraki, Japan
| | - Masanobu Kawachi
- Biodiversity Division, National Institute for Environmental Studies, Ibaraki, Japan
| | - Chinatsu Tsukakoshi
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Ibaraki, Japan
| | - Atsushi Nakamura
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Ibaraki, Japan
| | - Kyoko Hagino
- Center for Advanced Marine Core Research, Kochi University, Kochi, Japan
| | - Isao Inouye
- Faculty of Life and Environmental Sciences, University of Tsukuba, Ibaraki, Japan
| | - Ken-ichiro Ishida
- Faculty of Life and Environmental Sciences, University of Tsukuba, Ibaraki, Japan
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30
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Graham CLB, Newman H, Gillett FN, Smart K, Briggs N, Banzhaf M, Roper DI. A Dynamic Network of Proteins Facilitate Cell Envelope Biogenesis in Gram-Negative Bacteria. Int J Mol Sci 2021; 22:12831. [PMID: 34884635 PMCID: PMC8657477 DOI: 10.3390/ijms222312831] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Revised: 11/02/2021] [Accepted: 11/03/2021] [Indexed: 01/01/2023] Open
Abstract
Bacteria must maintain the ability to modify and repair the peptidoglycan layer without jeopardising its essential functions in cell shape, cellular integrity and intermolecular interactions. A range of new experimental techniques is bringing an advanced understanding of how bacteria regulate and achieve peptidoglycan synthesis, particularly in respect of the central role played by complexes of Sporulation, Elongation or Division (SEDs) and class B penicillin-binding proteins required for cell division, growth and shape. In this review we highlight relationships implicated by a bioinformatic approach between the outer membrane, cytoskeletal components, periplasmic control proteins, and cell elongation/division proteins to provide further perspective on the interactions of these cell division, growth and shape complexes. We detail the network of protein interactions that assist in the formation of peptidoglycan and highlight the increasingly dynamic and connected set of protein machinery and macrostructures that assist in creating the cell envelope layers in Gram-negative bacteria.
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Affiliation(s)
- Chris L. B. Graham
- School of Life Sciences, University of Warwick, Coventry CV4 7AL, UK; (C.L.B.G.); (H.N.); (F.N.G.); (K.S.); (N.B.)
| | - Hector Newman
- School of Life Sciences, University of Warwick, Coventry CV4 7AL, UK; (C.L.B.G.); (H.N.); (F.N.G.); (K.S.); (N.B.)
| | - Francesca N. Gillett
- School of Life Sciences, University of Warwick, Coventry CV4 7AL, UK; (C.L.B.G.); (H.N.); (F.N.G.); (K.S.); (N.B.)
- School of Biosciences, University of Birmingham, Birmingham B15 2TT, UK;
| | - Katie Smart
- School of Life Sciences, University of Warwick, Coventry CV4 7AL, UK; (C.L.B.G.); (H.N.); (F.N.G.); (K.S.); (N.B.)
| | - Nicholas Briggs
- School of Life Sciences, University of Warwick, Coventry CV4 7AL, UK; (C.L.B.G.); (H.N.); (F.N.G.); (K.S.); (N.B.)
| | - Manuel Banzhaf
- School of Biosciences, University of Birmingham, Birmingham B15 2TT, UK;
| | - David I. Roper
- School of Life Sciences, University of Warwick, Coventry CV4 7AL, UK; (C.L.B.G.); (H.N.); (F.N.G.); (K.S.); (N.B.)
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Utsunomiya H, Saiki N, Kadoguchi H, Fukudome M, Hashimoto S, Ueda M, Takechi K, Takano H. Genes encoding lipid II flippase MurJ and peptidoglycan hydrolases are required for chloroplast division in the moss Physcomitrella patens. PLANT MOLECULAR BIOLOGY 2021; 107:405-415. [PMID: 33078277 DOI: 10.1007/s11103-020-01081-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Accepted: 10/02/2020] [Indexed: 06/11/2023]
Abstract
Homologous genes for the peptidoglycan precursor flippase MurJ, and peptidoglycan hydrolases: lytic transglycosylase MltB, and DD-carboxypeptidase VanY are required for chloroplast division in the moss Physcomitrella patens. The moss Physcomitrella patens is used as a model plant to study plastid peptidoglycan biosynthesis. In bacteria, MurJ flippase transports peptidoglycan precursors from the cytoplasm to the periplasm. In this study, we identified a MurJ homolog (PpMurJ) in the P. patens genome. Bacteria employ peptidoglycan degradation and recycling pathways for cell division. We also searched the P. patens genome for genes homologous to bacterial peptidoglycan hydrolases and identified genes homologous for the lytic transglycosylase mltB, N-acetylglucosaminidase nagZ, and LD-carboxypeptidase ldcA in addition to a putative DD-carboxypeptidase vanY reported previously. Moreover, we found a ß-lactamase-like gene (Pplactamase). GFP fusion proteins with either PpMltB or PpVanY were detected in the chloroplasts, whereas fusion proteins with PpNagZ, PpLdcA, or Pplactamase localized in the cytoplasm. Experiments seeking PpMurJ-GFP fusion proteins failed. PpMurJ gene disruption in P. patens resulted in the appearance of macrochloroplasts in protonemal cells. Compared with the numbers of chloroplasts in wild-type plants (38.9 ± 4.9), PpMltB knockout and PpVanY knockout had lower numbers of chloroplasts (14.3 ± 6.7 and 28.1 ± 5.9, respectively). No differences in chloroplast numbers were observed after PpNagZ, PpLdcA, or Pplactamase single-knockout. Chloroplast numbers in PpMltB/PpVanY double-knockout cells were similar to those in PpMltB single-knockout cells. Zymogram analysis of the recombinant PpMltB protein revealed its peptidoglycan hydrolase activity. Our results imply that PpMurJ, PpMltB and PpVanY play a critical role in chloroplast division in the moss P. patens.
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Affiliation(s)
- Hanae Utsunomiya
- Graduate School of Science and Technology, Kumamoto University, Kumamoto, 860-8555, Japan
| | - Nozomi Saiki
- Graduate School of Science and Technology, Kumamoto University, Kumamoto, 860-8555, Japan
| | - Hayato Kadoguchi
- Faculty of Science, Kumamoto University, Kumamoto, 860-8555, Japan
| | - Masaya Fukudome
- Faculty of Science, Kumamoto University, Kumamoto, 860-8555, Japan
| | - Satomi Hashimoto
- Faculty of Science, Kumamoto University, Kumamoto, 860-8555, Japan
| | - Mami Ueda
- Faculty of Science, Kumamoto University, Kumamoto, 860-8555, Japan
| | - Katsuaki Takechi
- Faculty of Advanced Science and Technology, Kumamoto University, Kumamoto, 860-8555, Japan.
| | - Hiroyoshi Takano
- Faculty of Advanced Science and Technology, Kumamoto University, Kumamoto, 860-8555, Japan.
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Jang H, Do H, Kim CM, Kim GE, Lee JH, Park HH. Molecular basis of dimerization of lytic transglycosylase revealed by the crystal structure of MltA from Acinetobacter baumannii. IUCRJ 2021; 8:921-930. [PMID: 34804545 PMCID: PMC8562663 DOI: 10.1107/s2052252521008666] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Accepted: 08/18/2021] [Indexed: 06/13/2023]
Abstract
Peptidoglycan digestion by murein-degrading enzymes is a critical process in bacterial cell growth and/or cell division. The membrane-bound lytic murein transglycosylase A (MltA) is a murein-degrading enzyme; it catalyzes the cleavage of the β-1,4-glycosidic linkage between N-acetylmuramic acid and N-acetylglucosamine in peptidoglycans. Although substrate recognition and cleavage by MltA have been examined by previous structural and mutagenesis studies, the overall mechanism of MltA in conjunction with other functionally related molecules on the outer membrane of bacterial cells for peptidoglycan degradation has remained elusive. In this study, the crystal structure of MltA from the virulent human pathogen Acinetobacter baumannii is characterized and presented. The study indicated that MltA from A. baumannii forms homodimers via an extra domain which is specific to this species. Furthermore, the working mechanism of MltA with various functionally related proteins on the bacterial outer membrane was modeled based on the structural and biochemical analysis.
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Affiliation(s)
- Hyunseok Jang
- College of Pharmacy, Chung-Ang University, Seoul 06974, Republic of Korea
- Department of Global Innovative Drugs, Graduate School of Chung-Ang University, Seoul 06974, Republic of Korea
| | - Hackwon Do
- Unit of Research for Practical Application, Korea Polar Research Institute, Incheon 21990, Republic of Korea
- Department of Polar Sciences, University of Science and Technology, Incheon 21990, Republic of Korea
| | - Chang Min Kim
- Department of Global Innovative Drugs, Graduate School of Chung-Ang University, Seoul 06974, Republic of Korea
| | - Gi Eob Kim
- College of Pharmacy, Chung-Ang University, Seoul 06974, Republic of Korea
- Department of Global Innovative Drugs, Graduate School of Chung-Ang University, Seoul 06974, Republic of Korea
| | - Jun Hyuck Lee
- Unit of Research for Practical Application, Korea Polar Research Institute, Incheon 21990, Republic of Korea
- Department of Polar Sciences, University of Science and Technology, Incheon 21990, Republic of Korea
| | - Hyun Ho Park
- College of Pharmacy, Chung-Ang University, Seoul 06974, Republic of Korea
- Department of Global Innovative Drugs, Graduate School of Chung-Ang University, Seoul 06974, Republic of Korea
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Abstract
Most bacteria are protected from environmental offenses by a cell wall consisting of strong yet elastic peptidoglycan. The cell wall is essential for preserving bacterial morphology and viability, and thus the enzymes involved in the production and turnover of peptidoglycan have become preferred targets for many of our most successful antibiotics. In the past decades, Vibrio cholerae, the gram-negative pathogen causing the diarrheal disease cholera, has become a major model for understanding cell wall genetics, biochemistry, and physiology. More than 100 articles have shed light on novel cell wall genetic determinants, regulatory links, and adaptive mechanisms. Here we provide the first comprehensive review of V. cholerae's cell wall biology and genetics. Special emphasis is placed on the similarities and differences with Escherichia coli, the paradigm for understanding cell wall metabolism and chemical structure in gram-negative bacteria.
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Affiliation(s)
- Laura Alvarez
- Department of Molecular Biology and Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå Centre for Microbial Research (UCMR), Umeå University, Umeå SE-90187, Sweden;
| | - Sara B Hernandez
- Department of Molecular Biology and Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå Centre for Microbial Research (UCMR), Umeå University, Umeå SE-90187, Sweden;
| | - Felipe Cava
- Department of Molecular Biology and Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå Centre for Microbial Research (UCMR), Umeå University, Umeå SE-90187, Sweden;
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Figueroa-Cuilan WM, Randich AM, Dunn CM, Santiago-Collazo G, Yowell A, Brown PJB. Diversification of LytM Protein Functions in Polar Elongation and Cell Division of Agrobacterium tumefaciens. Front Microbiol 2021; 12:729307. [PMID: 34489918 PMCID: PMC8416486 DOI: 10.3389/fmicb.2021.729307] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Accepted: 07/26/2021] [Indexed: 12/05/2022] Open
Abstract
LytM-domain containing proteins are LAS peptidases (lysostaphin-type enzymes, D-Ala-D-Ala metallopeptidases, and sonic hedgehog) and are known to play diverse roles throughout the bacterial cell cycle through direct or indirect hydrolysis of the bacterial cell wall. A subset of the LytM factors are catalytically inactive but regulate the activity of other cell wall hydrolases and are classically described as cell separation factors NlpD and EnvC. Here, we explore the function of four LytM factors in the alphaproteobacterial plant pathogen Agrobacterium tumefaciens. An LmdC ortholog (Atu1832) and a MepM ortholog (Atu4178) are predicted to be catalytically active. While Atu1832 does not have an obvious function in cell growth or division, Atu4178 is essential for polar growth and likely functions as a space-making endopeptidase that cleaves amide bonds in the peptidoglycan cell wall during elongation. The remaining LytM factors are degenerate EnvC and NlpD orthologs. Absence of these proteins results in striking phenotypes indicative of misregulation of cell division and growth pole establishment. The deletion of an amidase, AmiC, closely phenocopies the deletion of envC suggesting that EnvC might regulate AmiC activity. The NlpD ortholog DipM is unprecedently essential for viability and depletion results in the misregulation of early stages of cell division, contrasting with the canonical view of DipM as a cell separation factor. Finally, we make the surprising observation that absence of AmiC relieves the toxicity induced by dipM overexpression. Together, these results suggest EnvC and DipM may function as regulatory hubs with multiple partners to promote proper cell division and establishment of polarity.
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Affiliation(s)
| | - Amelia M. Randich
- Department of Biology, University of Scranton, Scranton, PA, United States
| | - Caroline M. Dunn
- Division of Biological Sciences, University of Missouri, Columbia, MO, United States
| | - Gustavo Santiago-Collazo
- Division of Biological Sciences, University of Missouri, Columbia, MO, United States
- Molecular Pathogenesis and Therapeutics Graduate Program, University of Missouri, Columbia, MO, United States
| | - Andrew Yowell
- Division of Biological Sciences, University of Missouri, Columbia, MO, United States
| | - Pamela J. B. Brown
- Division of Biological Sciences, University of Missouri, Columbia, MO, United States
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Hyun Y, Baek Y, Lee C, Ki N, Ahn J, Ryu S, Ha NC. Structure and Function of the Autolysin SagA in the Type IV Secretion System of Brucella abortus. Mol Cells 2021; 44:517-528. [PMID: 34112742 PMCID: PMC8334348 DOI: 10.14348/molcells.2021.0011] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 02/17/2021] [Accepted: 02/17/2021] [Indexed: 11/27/2022] Open
Abstract
A recent genetic study with Brucella abortus revealed the secretion activator gene A (SagA) as an autolysin component creating pores in the peptidoglycan (PGN) layer for the type IV secretion system (T4SS) and peptidoglycan hydrolase inhibitor A (PhiA) as an inhibitor of SagA. In this study, we determined the crystal structures of both SagA and PhiA. Notably, the SagA structure contained a PGN fragment in a space between the N- and C-terminal domains, showing the substrate-dependent hinge motion of the domains. The purified SagA fully hydrolyzed the meso-diaminopimelic acid (DAP)-type PGN, showing a higher activity than hen egg-white lysozyme. The PhiA protein exhibiting tetrameric assembly failed to inhibit SagA activity in our experiments. Our findings provide implications for the molecular basis of the SagA-PhiA system of B. abortus. The development of inhibitors of SagA would further contribute to controlling brucellosis by attenuating the function of T4SS, the major virulence factor of Brucella.
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Affiliation(s)
- Yongseong Hyun
- Department of Agricultural Biotechnology, Research Institute for Agriculture and Life Sciences, Center for Food and Bioconvergence, CALS, Seoul National University, Seoul 08826, Korea
| | - Yeongjin Baek
- Department of Agricultural Biotechnology, Research Institute for Agriculture and Life Sciences, Center for Food and Bioconvergence, CALS, Seoul National University, Seoul 08826, Korea
| | - Chanyoung Lee
- Department of Agricultural Biotechnology, Research Institute for Agriculture and Life Sciences, Center for Food and Bioconvergence, CALS, Seoul National University, Seoul 08826, Korea
| | - Nayeon Ki
- Department of Agricultural Biotechnology, Research Institute for Agriculture and Life Sciences, Center for Food and Bioconvergence, CALS, Seoul National University, Seoul 08826, Korea
| | - Jinsook Ahn
- Department of Agricultural Biotechnology, Research Institute for Agriculture and Life Sciences, Center for Food and Bioconvergence, CALS, Seoul National University, Seoul 08826, Korea
| | - Sangryeol Ryu
- Department of Agricultural Biotechnology, Research Institute for Agriculture and Life Sciences, Center for Food and Bioconvergence, CALS, Seoul National University, Seoul 08826, Korea
| | - Nam-Chul Ha
- Department of Agricultural Biotechnology, Research Institute for Agriculture and Life Sciences, Center for Food and Bioconvergence, CALS, Seoul National University, Seoul 08826, Korea
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The Lysozyme Inhibitor Thionine Acetate Is Also an Inhibitor of the Soluble Lytic Transglycosylase Slt35 from Escherichia coli. Molecules 2021; 26:molecules26144189. [PMID: 34299465 PMCID: PMC8307938 DOI: 10.3390/molecules26144189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 07/03/2021] [Accepted: 07/06/2021] [Indexed: 11/18/2022] Open
Abstract
Lytic transglycosylases such as Slt35 from E. coli are enzymes involved in bacterial cell wall remodelling and recycling, which represent potential targets for novel antibacterial agents. Here, we investigated a series of known glycosidase inhibitors for their ability to inhibit Slt35. While glycosidase inhibitors such as 1-deoxynojirimycin, castanospermine, thiamet G and miglitol had no effect, the phenothiazinium dye thionine acetate was found to be a weak inhibitor. IC50 values and binding constants for thionine acetate were similar for Slt35 and the hen egg white lysozyme. Molecular docking simulations suggest that thionine binds to the active site of both Slt35 and lysozyme, although it does not make direct interactions with the side-chain of the catalytic Asp and Glu residues as might be expected based on other inhibitors. Thionine acetate also increased the potency of the beta-lactam antibiotic ampicillin against a laboratory strain of E. coli.
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Okubo T, Toyoda A, Fukuhara K, Uchiyama I, Harigaya Y, Kuroiwa M, Suzuki T, Murakami Y, Suwa Y, Takami H. The physiological potential of anammox bacteria as revealed by their core genome structure. DNA Res 2021; 28:6046978. [PMID: 33367889 PMCID: PMC7814187 DOI: 10.1093/dnares/dsaa028] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Accepted: 12/04/2020] [Indexed: 01/25/2023] Open
Abstract
We present here the second complete genome of anaerobic ammonium oxidation (anammox) bacterium, Candidatus (Ca.) Brocadia pituitae, along with those of a nitrite oxidizer and two incomplete denitrifiers from the anammox bacterial community (ABC) metagenome. Although NO2− reduction to NO is considered to be the first step in anammox, Ca. B. pituitae lacks nitrite reductase genes (nirK and nirS) responsible for this reaction. Comparative genomics of Ca. B. pituitae with Ca. Kuenenia stuttgartiensis and six other anammox bacteria with nearly complete genomes revealed that their core genome structure contains 1,152 syntenic orthologues. But nitrite reductase genes were absent from the core, whereas two other Brocadia species possess nirK and these genes were horizontally acquired from multiple lineages. In contrast, at least five paralogous hydroxylamine oxidoreductase genes containing candidate ones (hao2 and hao3) encoding another nitrite reductase were observed in the core. Indeed, these two genes were also significantly expressed in Ca. B. pituitae as in other anammox bacteria. Because many nirS and nirK genes have been detected in the ABC metagenome, Ca. B. pituitae presumably utilises not only NO supplied by the ABC members but also NO and/or NH2OH by self-production for anammox metabolism.
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Affiliation(s)
- Takashi Okubo
- Marine Microbiology, Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa 277-8564, Japan
| | - Atsushi Toyoda
- Comparative Genomics Laboratory, National Institute of Genetics, Mishima 411-8540, Japan
| | - Kohei Fukuhara
- Department of Biological Sciences, Chuo University, Bunkyo, Tokyo 112-8851, Japan
| | - Ikuo Uchiyama
- Laboratory of Genome Informatics, National Institute for Basic Biology, National Institutes of Natural Sciences, Myodaiji, Okazaki 444-8585, Japan
| | - Yuhki Harigaya
- Department of Biological Sciences, Chuo University, Bunkyo, Tokyo 112-8851, Japan
| | - Megumi Kuroiwa
- Department of Biological Sciences, Chuo University, Bunkyo, Tokyo 112-8851, Japan
| | - Takuma Suzuki
- Department of Biological Sciences, Chuo University, Bunkyo, Tokyo 112-8851, Japan
| | - Yuka Murakami
- Department of Biological Sciences, Chuo University, Bunkyo, Tokyo 112-8851, Japan
| | - Yuichi Suwa
- Department of Biological Sciences, Chuo University, Bunkyo, Tokyo 112-8851, Japan
| | - Hideto Takami
- Marine Microbiology, Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa 277-8564, Japan
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38
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Dörr T. Understanding tolerance to cell wall-active antibiotics. Ann N Y Acad Sci 2021; 1496:35-58. [PMID: 33274447 PMCID: PMC8359209 DOI: 10.1111/nyas.14541] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 11/02/2020] [Accepted: 11/04/2020] [Indexed: 12/19/2022]
Abstract
Antibiotic tolerance-the ability of bacteria to survive for an extended time in the presence of bactericidal antibiotics-is an understudied contributor to antibiotic treatment failure. Herein, I review the manifestations, mechanisms, and clinical relevance of tolerance to cell wall-active (CWA) antibiotics, one of the most important groups of antibiotics at the forefront of clinical use. I discuss definitions of tolerance and assays for tolerance detection, comprehensively discuss the mechanism of action of β-lactams and other CWA antibiotics, and then provide an overview of how cells mitigate the potentially lethal effects of CWA antibiotic-induced cell damage to become tolerant. Lastly, I discuss evidence for a role of CWA antibiotic tolerance in clinical antibiotic treatment failure.
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Affiliation(s)
- Tobias Dörr
- Weill Institute for Cell and Molecular Biology, Department of Microbiology, and Cornell Institute of Host–Pathogen Interactions and DiseaseCornell UniversityIthacaNew York
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Han P, Hu Y, An X, Song L, Fan H, Tong Y. Biochemical and genomic characterization of a novel bacteriophage BUCT555 lysing Stenotrophomonas maltophilia. Virus Res 2021; 301:198465. [PMID: 34052250 DOI: 10.1016/j.virusres.2021.198465] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2021] [Revised: 05/20/2021] [Accepted: 05/21/2021] [Indexed: 12/25/2022]
Abstract
Stenotrophomonas maltophilia is a common conditional pathogen, and it is naturally resistant to most commonly used clinical antibiotics. The bacteriophage is considered to be a potential antibiotic alternative for treating multi-drug-resistant bacteria. In this study, a bacteriophage BUCT555 was isolated from hospital sewage for lysing the clinical multi-drug resistant Stenotrophomonas maltophilia. Electron microscopy studies revealed this phage belongs to the Podoviridae family. The double-stranded DNA genome of bacteriophage BUCT555 is composed of 39,440 bp with a GC content of 61.43%. The genome contains 57 open reading frames, 14 of which had assigned functions, while no virulence related genes, antibiotic resistance genes or tRNA were identified. The burst size of BUCT555 was 204 pfu per infected cell. Structure proteins of bacteriophage BUCT555 generated by SDS-PAGE and HPLC-MS revealed that it contains seven proteins with molecular weight ranging from 19 to 89 kDa. BLASTn analysis showed that phage BUCT555 has 2% homology with other phages in NCBI database, suggesting BUCT555 is a new phage genus of Podoviridae that infects Stenotrophomonas maltophilia. Characterization of the bacteriophage BUCT555 enriches our knowledge about the diversity of Stenotrophomonas maltophilia bacteriophages.
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Affiliation(s)
- Pengjun Han
- College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, China
| | - Yunjia Hu
- College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, China
| | - Xiaoping An
- College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, China
| | - Lihua Song
- College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, China.
| | - Huahao Fan
- College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, China.
| | - Yigang Tong
- College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, China; Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, China.
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Modulation of Peptidoglycan Synthesis by Recycled Cell Wall Tetrapeptides. Cell Rep 2021; 31:107578. [PMID: 32348759 DOI: 10.1016/j.celrep.2020.107578] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Revised: 03/12/2020] [Accepted: 04/06/2020] [Indexed: 12/20/2022] Open
Abstract
The bacterial cell wall is made of peptidoglycan (PG), a polymer that is essential for the maintenance of cell shape and survival. During growth, bacteria remodel their PG, releasing fragments that are predominantly re-internalized and recycled. Here, we show that Vibrio cholerae recycles PG fragments modified with non-canonical d-amino acids (NCDAA), which lead to the accumulation of cytosolic PG tetrapeptides. We demonstrate that the accumulation of recycled tetrapeptides has two regulatory consequences for the cell wall: reduction of d,d-cross-linkage and reduction of PG synthesis. We further demonstrate that l,d-carboxypeptidases from five different species show a preferential activity for substrates containing canonical (d-alanine) versus non-canonical (d-methionine) d-amino acids, suggesting that the accumulation of intracellular tetrapeptides in NCDAA-rich environments is widespread. Collectively, this work reveals a regulatory role of NCDAA linking PG recycling and synthesis to promote optimal cell wall assembly and composition in the stationary phase.
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Nowak J, Visnovsky SB, Pitman AR, Cruz CD, Palmer J, Fletcher GC, Flint S. Biofilm Formation by Listeria monocytogenes 15G01, a Persistent Isolate from a Seafood-Processing Plant, Is Influenced by Inactivation of Multiple Genes Belonging to Different Functional Groups. Appl Environ Microbiol 2021; 87:e02349-20. [PMID: 33741610 PMCID: PMC8117777 DOI: 10.1128/aem.02349-20] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Accepted: 02/25/2021] [Indexed: 01/13/2023] Open
Abstract
Listeria monocytogenes is a ubiquitous foodborne pathogen that results in a high rate of mortality in sensitive and immunocompromised people. Contamination of food with L. monocytogenes is thought to occur during food processing, most often as a result of the pathogen producing a biofilm that persists in the environment and acting as the source for subsequent dispersal of cells onto food. A survey of seafood-processing plants in New Zealand identified the persistent strain 15G01, which has a high capacity to form biofilms. In this study, a transposon library of L. monocytogenes 15G01 was screened for mutants with altered biofilm formation, assessed by a crystal violet assay, to identify genes involved in biofilm formation. This screen identified 36 transposants that showed a significant change in biofilm formation compared to the wild type. The insertion sites were in 27 genes, 20 of which led to decreased biofilm formation and seven to an increase. Two insertions were in intergenic regions. Annotation of the genes suggested that they are involved in diverse cellular processes, including stress response, autolysis, transporter systems, and cell wall/membrane synthesis. Analysis of the biofilms produced by the transposants using scanning electron microscopy and fluorescence microscopy showed notable differences in the structure of the biofilms compared to the wild type. In particular, inactivation of uvrB and mltD produced coccoid-shaped cells and elongated cells in long chains, respectively, and the mgtB mutant produced a unique biofilm with a sandwich structure which was reversed to the wild-type level upon magnesium addition. The mltD transposant was successfully complemented with the wild-type gene, whereas the phenotypes were not or only partially restored for the remaining mutants.IMPORTANCE The major source of contamination of food with Listeria monocytogenes is thought to be due to biofilm formation and/or persistence in food-processing plants. By establishing as a biofilm, L. monocytogenes cells become harder to eradicate due to their increased resistance to environmental threats. Understanding the genes involved in biofilm formation and their influence on biofilm structure will help identify new ways to eliminate harmful biofilms in food processing environments. To date, multiple genes have been identified as being involved in biofilm formation by L. monocytogenes; however, the exact mechanism remains unclear. This study identified four genes associated with biofilm formation by a persistent strain. Extensive microscopic analysis illustrated the effect of the disruption of mgtB, clsA, uvrB, and mltD and the influence of magnesium on the biofilm structure. The results strongly suggest an involvement in biofilm formation for the four genes and provide a basis for further studies to analyze gene regulation to assess the specific role of these biofilm-associated genes.
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Affiliation(s)
- Jessika Nowak
- The New Zealand Institute for Plant and Food Research Limited, Auckland, New Zealand
- Institute of Food, Nutrition and Human Health, Massey University, Palmerston North, New Zealand
| | - Sandra B Visnovsky
- The New Zealand Institute for Plant and Food Research Limited, Lincoln, New Zealand
| | - Andrew R Pitman
- The Foundation for Arable Research, Christchurch, New Zealand
| | - Cristina D Cruz
- The New Zealand Institute for Plant and Food Research Limited, Auckland, New Zealand
- Drug Research Program, Division of Pharmaceutical Biosciences, Faculty of Pharmacy, University of Helsinki, Helsinki, Finland
| | - Jon Palmer
- Institute of Food, Nutrition and Human Health, Massey University, Palmerston North, New Zealand
| | - Graham C Fletcher
- The New Zealand Institute for Plant and Food Research Limited, Auckland, New Zealand
| | - Steve Flint
- Institute of Food, Nutrition and Human Health, Massey University, Palmerston North, New Zealand
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CwlQ Is Required for Swarming Motility but Not Flagellar Assembly in Bacillus subtilis. J Bacteriol 2021; 203:JB.00029-21. [PMID: 33649146 DOI: 10.1128/jb.00029-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Accepted: 02/22/2021] [Indexed: 11/20/2022] Open
Abstract
Lytic enzymes play an essential role in the remodeling of bacterial peptidoglycan (PG), an extracellular mesh-like structure that retains the membrane in the context of high internal osmotic pressure. Peptidoglycan must be unfailingly stable to preserve cell integrity, but must also be dynamically remodeled for the cell to grow, divide, and insert macromolecular machines. The flagellum is one such macromolecular machine that transits the PG, and flagellar insertion is aided by localized activity of a dedicated PG lyase in Gram-negative bacteria. To date, there is no known dedicated lyase in Gram-positive bacteria for the insertion of flagella. Here, we take a reverse-genetic candidate-gene approach and find that cells mutated for the lytic transglycosylase CwlQ exhibit a severe defect in flagellum-dependent swarming motility. We further show that CwlQ is expressed by the motility sigma factor SigD and is secreted by the type III secretion system housed inside the flagellum. Nonetheless, cells with mutations of CwlQ remain proficient for flagellar biosynthesis even when mutated in combination with four other lyases related to motility (LytC, LytD, LytF, and CwlO). The PG lyase (or lyases) essential for flagellar synthesis in B. subtilis, if any, remains unknown.IMPORTANCE Bacteria are surrounded by a wall of peptidoglycan and early work in Bacillus subtilis was the first to suggest that bacteria needed to enzymatically remodel the wall to permit insertion of the flagellum. No PG remodeling enzyme alone or in combination, however, has been found to be essential for flagellar assembly in B. subtilis Here, we take a reverse-genetic candidate-gene approach and find that the PG lytic transglycosylase CwlQ is required for swarming motility. Subsequent characterization determined that while CwlQ was coexpressed with motility genes and is secreted by the flagellar secretion apparatus, it was not required for flagellar synthesis. The PG lyase needed for flagellar assembly in B. subtilis remains unknown.
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Rai A, Bhattacharjee A. Molecular profiling of microbial community structure and their CAZymes via metagenomics, from Tsomgo lake in the Eastern Himalayas. Arch Microbiol 2021; 203:3135-3146. [PMID: 33813595 DOI: 10.1007/s00203-021-02278-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Revised: 03/09/2021] [Accepted: 03/11/2021] [Indexed: 02/01/2023]
Abstract
The present study is the first of its kind which is focused on Tsomgo lake, a high-altitude lake, located in the Eastern Himalayas of Sikkim. To get a major insight into the bacterial diversity, the shotgun sequencing was carried out in Illumina platform. Our results showed that both the samples TLSS1 (soil) and TLSW1 (water), had Proteobacteria as the most abundant taxa. Cluster of Orthologous group (COG) functional category of TLSS1 has 1,46,965 predicted functions. Cluster of Orthologous Group (COG) functional category of TLSW1 has 1,34,773 predicted functions. Kyoto Encyclopedia of Gene and Genomes (KEGG) functional category of TLSS1 has 1,76,825 predicted functions, most of the sequence fall in metabolism followed by Environmental information processing function. (KEGG) functional category of TLSW1 has 1,62,696 predicted functions and it follows the same pattern as TLSS1. Our studies also provide insight into the presence of distribution of different carbohydrate-active enzymes (CAZymes) present in Tsomgo lake. We have found that in case of both the samples TLSW1 and TLSS1, GlycosylTransferases were active followed by GlycosylHydrolase. The result found, represents for the first time very important findings related to the microbial diversity and the abundance of CAZymes in Tsomgo lake one of the pristine high-altitude lakes in Sikkim.
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Affiliation(s)
- Aditi Rai
- Department of Microbiology, University of North Bengal, Darjeeling, 734013, West Bengal, India
| | - Arindam Bhattacharjee
- Department of Microbiology, University of North Bengal, Darjeeling, 734013, West Bengal, India.
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44
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Islam MS, Yang X, Euler CW, Han X, Liu J, Hossen MI, Zhou Y, Li J. Application of a novel phage ZPAH7 for controlling multidrug-resistant Aeromonas hydrophila on lettuce and reducing biofilms. Food Control 2021. [DOI: 10.1016/j.foodcont.2020.107785] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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Müller M, Calvert M, Hottmann I, Kluj RM, Teufel T, Balbuchta K, Engelbrecht A, Selim KA, Xu Q, Borisova M, Titz A, Mayer C. The exo-β-N-acetylmuramidase NamZ from Bacillus subtilis is the founding member of a family of exo-lytic peptidoglycan hexosaminidases. J Biol Chem 2021; 296:100519. [PMID: 33684445 PMCID: PMC8054146 DOI: 10.1016/j.jbc.2021.100519] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Revised: 02/27/2021] [Accepted: 03/04/2021] [Indexed: 11/11/2022] Open
Abstract
Endo-β-N-acetylmuramidases, commonly known as lysozymes, are well-characterized antimicrobial enzymes that catalyze an endo-lytic cleavage of peptidoglycan; i.e., they hydrolyze the β-1,4-glycosidic bonds connecting N-acetylmuramic acid (MurNAc) and N-acetylglucosamine (GlcNAc). In contrast, little is known about exo-β-N-acetylmuramidases, which catalyze an exo-lytic cleavage of β-1,4-MurNAc entities from the non-reducing ends of peptidoglycan chains. Such an enzyme was identified earlier in the bacterium Bacillus subtilis, but the corresponding gene has remained unknown so far. We now report that ybbC of B. subtilis, renamed namZ, encodes the reported exo-β-N-acetylmuramidase. A ΔnamZ mutant accumulated specific cell wall fragments and showed growth defects under starvation conditions, indicating a role of NamZ in cell wall turnover and recycling. Recombinant NamZ protein specifically hydrolyzed the artificial substrate para-nitrophenyl β-MurNAc and the peptidoglycan-derived disaccharide MurNAc-β-1,4-GlcNAc. Together with the exo-β-N-acetylglucosaminidase NagZ and the exo-muramoyl-l-alanine amidase AmiE, NamZ degraded intact peptidoglycan by sequential hydrolysis from the non-reducing ends. A structure model of NamZ, built on the basis of two crystal structures of putative orthologs from Bacteroides fragilis, revealed a two-domain structure including a Rossmann-fold-like domain that constitutes a unique glycosidase fold. Thus, NamZ, a member of the DUF1343 protein family of unknown function, is now classified as the founding member of a new family of glycosidases (CAZy GH171; www.cazy.org/GH171.html). NamZ-like peptidoglycan hexosaminidases are mainly present in the phylum Bacteroidetes and less frequently found in individual genomes within Firmicutes (Bacilli, Clostridia), Actinobacteria, and γ-proteobacteria.
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Affiliation(s)
- Maraike Müller
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany
| | - Matthew Calvert
- Chemical Biology of Carbohydrates, Helmholtz Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz Centre for Infection Research (HZI), Saarbrücken, Germany; Deutsches Zentrum für Infektionsforschung (DZIF), Standort Hannover-Braunschweig, Germany; Department of Chemistry, Saarland University, Saarbrücken, Germany
| | - Isabel Hottmann
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany
| | - Robert Maria Kluj
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany
| | - Tim Teufel
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany
| | - Katja Balbuchta
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany
| | - Alicia Engelbrecht
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany
| | - Khaled A Selim
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany; Chemistry of Natural and Microbial Products Department, Pharmaceutical and Drug Industries Research Division, National Research Center, Giza, Egypt
| | - Qingping Xu
- GM/CA @ APS, Argonne National Laboratory, Lemont, Illinois, USA
| | - Marina Borisova
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany
| | - Alexander Titz
- Chemical Biology of Carbohydrates, Helmholtz Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz Centre for Infection Research (HZI), Saarbrücken, Germany; Deutsches Zentrum für Infektionsforschung (DZIF), Standort Hannover-Braunschweig, Germany; Department of Chemistry, Saarland University, Saarbrücken, Germany
| | - Christoph Mayer
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany.
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New Insights into the Co-Occurrences of Glycoside Hydrolase Genes among Prokaryotic Genomes through Network Analysis. Microorganisms 2021; 9:microorganisms9020427. [PMID: 33669523 PMCID: PMC7922503 DOI: 10.3390/microorganisms9020427] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2021] [Revised: 02/06/2021] [Accepted: 02/14/2021] [Indexed: 12/21/2022] Open
Abstract
Glycoside hydrolase (GH) represents a crucial category of enzymes for carbohydrate utilization in most organisms. A series of glycoside hydrolase families (GHFs) have been classified, with relevant information deposited in the CAZy database. Statistical analysis indicated that most GHFs (134 out of 154) were prone to exist in bacteria rather than archaea, in terms of both occurrence frequencies and average gene numbers. Co-occurrence analysis suggested the existence of strong or moderate-strong correlations among 63 GHFs. A combination of network analysis by Gephi and functional classification among these GHFs demonstrated the presence of 12 functional categories (from group A to L), with which the corresponding microbial collections were subsequently labeled, respectively. Interestingly, a progressive enrichment of particular GHFs was found among several types of microbes, and type-L as well as type-E microbes were deemed as functional intensified species which formed during the microbial evolution process toward efficient decomposition of lignocellulose as well as pectin, respectively. Overall, integrating network analysis and enzymatic functional classification, we were able to provide a new angle of view for GHs from known prokaryotic genomes, and thus this study is likely to guide the selection of GHs and microbes for efficient biomass utilization.
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47
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Zellner B, Mengin-Lecreulx D, Tully B, Gunning WT, Booth R, Huntley JF. A Francisella tularensis L,D-carboxypeptidase plays important roles in cell morphology, envelope integrity, and virulence. Mol Microbiol 2021; 115:1357-1378. [PMID: 33469978 DOI: 10.1111/mmi.14685] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 01/13/2021] [Accepted: 01/14/2021] [Indexed: 12/15/2022]
Abstract
Francisella tularensis is a Gram-negative, intracellular bacterium that causes the zoonotic disease tularemia. Intracellular pathogens, including F. tularensis, have evolved mechanisms to survive in the harsh environment of macrophages and neutrophils, where they are exposed to cell envelope-damaging molecules. The bacterial cell wall, primarily composed of peptidoglycan (PG), maintains cell morphology, structure, and membrane integrity. Intracellular Gram-negative bacteria protect themselves from macrophage and neutrophil killing by recycling and repairing damaged PG--a process that involves over 50 different PG synthesis and recycling enzymes. Here, we identified a PG recycling enzyme, L,D-carboxypeptidase A (LdcA), of F. tularensis that is responsible for converting PG tetrapeptide stems to tripeptide stems. Unlike E. coli LdcA and most other orthologs, F. tularensis LdcA does not localize to the cytoplasm and also exhibits L,D-endopeptidase activity, converting PG pentapeptide stems to tripeptide stems. Loss of F. tularensis LdcA led to altered cell morphology and membrane integrity, as well as attenuation in a mouse pulmonary infection model and in primary and immortalized macrophages. Finally, an F. tularensis ldcA mutant protected mice against virulent Type A F. tularensis SchuS4 pulmonary challenge.
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Affiliation(s)
- Briana Zellner
- Department of Medical Microbiology and Immunology, University of Toledo, Toledo, OH, USA
| | - Dominique Mengin-Lecreulx
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Brenden Tully
- Department of Medical Microbiology and Immunology, University of Toledo, Toledo, OH, USA
| | | | - Robert Booth
- Department of Pathology, University of Toledo, Toledo, OH, USA
| | - Jason F Huntley
- Department of Medical Microbiology and Immunology, University of Toledo, Toledo, OH, USA
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Nakamura T, Shimizu T, Inagaki F, Okazaki S, Saha SS, Uda A, Watanabe K, Watarai M. Identification of Membrane-Bound Lytic Murein Transglycosylase A (MltA) as a Growth Factor for Francisella novicida in a Silkworm Infection Model. Front Cell Infect Microbiol 2021; 10:581864. [PMID: 33553001 PMCID: PMC7862118 DOI: 10.3389/fcimb.2020.581864] [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: 07/13/2020] [Accepted: 12/04/2020] [Indexed: 12/22/2022] Open
Abstract
Francisella tularensis, the causative agent of tularemia, is transmitted by arthropod vectors within mammalian hosts. The detailed mechanisms contributing to growth and survival of Francisella within arthropod remain poorly understood. To identify novel factors supporting growth and survival of Francisella within arthropods, a transposon mutant library of F. tularensis subsp. novicida (F. novicida) was screened using an F. novicida-silkworm infection model. Among 750 transposon mutants screened, the mltA-encoding membrane-bound lytic murein transglycosylase A (MltA) was identified as a novel growth factor of F. novicida in silkworms. Silkworms infection with an mltA deletion mutant (ΔmltA) resulted in a reduction in the number of bacteria and prolonged survival. The ΔmltA strain exhibited limited intracellular growth and cytotoxicity in BmN4 silkworm ovary cells. Moreover, the ΔmltA strain induced higher expression of the antimicrobial peptide in silkworms compared to the wild-type strain. These results suggest that F. novicida MltA contributes to the survival of F. novicida in silkworms via immune suppression-related mechanisms. Intracellular growth of the ΔmltA strain was also reduced in human monocyte THP-1 cells. These results also suggest the contribution of MltA to pathogenicity in humans and utility of the F. novicida-silkworm infection model to explore Francisella infection.
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Affiliation(s)
- Takemasa Nakamura
- Laboratory of Veterinary Public Health, Joint Faculty of Veterinary Medicine, Yamaguchi University, Yamaguchi, Japan
| | - Takashi Shimizu
- Laboratory of Veterinary Public Health, Joint Faculty of Veterinary Medicine, Yamaguchi University, Yamaguchi, Japan
| | - Fumiya Inagaki
- Laboratory of Veterinary Public Health, Joint Faculty of Veterinary Medicine, Yamaguchi University, Yamaguchi, Japan
| | - Shoma Okazaki
- Laboratory of Veterinary Public Health, Joint Faculty of Veterinary Medicine, Yamaguchi University, Yamaguchi, Japan
| | - Shib Shankar Saha
- Department of Pathology and Parasitology, Patuakhali Science and Technology University, Barisal, Bangladesh
| | - Akihiko Uda
- Department of Veterinary Science, National Institute of Infectious Diseases, Tokyo, Japan
| | - Kenta Watanabe
- Laboratory of Veterinary Public Health, Joint Faculty of Veterinary Medicine, Yamaguchi University, Yamaguchi, Japan
| | - Masahisa Watarai
- Laboratory of Veterinary Public Health, Joint Faculty of Veterinary Medicine, Yamaguchi University, Yamaguchi, Japan
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49
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Bohrhunter JL, Rohs PDA, Torres G, Yunck R, Bernhardt TG. MltG activity antagonizes cell wall synthesis by both types of peptidoglycan polymerases in Escherichia coli. Mol Microbiol 2020; 115:1170-1180. [PMID: 33278861 DOI: 10.1111/mmi.14660] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2019] [Revised: 11/25/2020] [Indexed: 12/23/2022]
Abstract
Bacterial cells are surrounded by a peptidoglycan (PG) cell wall. This structure is essential for cell integrity and its biogenesis pathway is a key antibiotic target. Most bacteria utilize two types of synthases that polymerize glycan strands and crosslink them: class A penicillin-binding proteins (aPBPs) and complexes of SEDS proteins and class B PBPs (bPBPs). Although the enzymatic steps of PG synthesis are well characterized, the steps involved in terminating PG glycan polymerization remain poorly understood. A few years ago, the conserved lytic transglycosylase MltG was identified as a potential terminase for PG synthesis in Escherichia coli. However, characterization of the in vivo function of MltG was hampered by the lack of a growth or morphological phenotype in ΔmltG cells. Here, we report the isolation of MltG-defective mutants as suppressors of lethal deficits in either aPBP or SEDS/bPBP PG synthase activity. We used this phenotype to perform a domain-function analysis for MltG, which revealed that access to the inner membrane is important for its in vivo activity. Overall, our results support a model in which MltG functions as a terminase for both classes of PG synthases by cleaving PG glycans as they are being actively synthesized.
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Affiliation(s)
| | | | - Grasiela Torres
- Department of Microbiology, Harvard Medical School, Boston, MA, USA
| | - Rachel Yunck
- Department of Microbiology, Harvard Medical School, Boston, MA, USA
| | - Thomas G Bernhardt
- Department of Microbiology, Harvard Medical School, Boston, MA, USA.,Howard Hughes Medical Institute, Chevy Chase, 20815, MD, USA
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50
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Gong Z, Lv X, Li C, Gu Y, Fan X, Sun Q, Tong Y, Zhao F, Xing S, Pei G, Li Q, Xie L, Xie J. Genomic and proteomic portrait of a novel mycobacteriophage SWU2 isolated from China. INFECTION GENETICS AND EVOLUTION 2020; 87:104665. [PMID: 33279716 DOI: 10.1016/j.meegid.2020.104665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Revised: 11/22/2020] [Accepted: 12/01/2020] [Indexed: 11/30/2022]
Abstract
Phage therapy, especially combination with antibiotics, was revitalized to control the antibiotics resistance. Mycobacteriophage, the phage of mycobacterium with the most notorious Mycobacterium tuberculosis (M. tuberculosis), was intensively explored. A novel mycobacteriophage SWU2 was isolated from a soil sample collected at Nanchang city, Jiangxi province, China, by using Mycolicibacterium smegmatis (M. smegmatis) mc2 155 as the host. Phage morphology and biology were characterized. Phage structure proteins were analyzed by LC-MS/MS. The putative functions of phage proteins and multi-genome comparison were performed with bioinformatics. The transmission electron microscopy result indicated that this phage belongs to Siphoviridae of Caudovirales. Plaques of SWU2 appeared clear but small. In a one-step growth test, we demonstrated that SWU2 had a latent period of 30 min and a logarithmic phase of 120 min. Among the 76 predicted Open Reading Frames (ORFs), 9 ORFs were identified as phage structure proteins of SWU2. The assembled phage genome size is 50,013 bp, with 62.7% of G + C content. SWU2 genome sequence shares 88% identity with Mycobacterium phages HINdeR and Timshel, differing in substitutions, insertions and deletions in SWU2. Phylogenetic tree revealed that SWU2 is grouped into A7 sub-cluster. There are several substitutions, insertions and deletions in SWU2 genome in comparison with close cousin phages HINdeR and Timshel. The new phage adds another dimension of abundance to the mycobacteriophages.
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Affiliation(s)
- Zhen Gong
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of Education, Chongqing Municipal Key Laboratory of Karst Environment, School of Life Sciences, Southwest University, Beibei, Chongqing 400715, China
| | - Xi Lv
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of Education, Chongqing Municipal Key Laboratory of Karst Environment, School of Life Sciences, Southwest University, Beibei, Chongqing 400715, China
| | - Chunyan Li
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of Education, Chongqing Municipal Key Laboratory of Karst Environment, School of Life Sciences, Southwest University, Beibei, Chongqing 400715, China
| | - Yinzhong Gu
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of Education, Chongqing Municipal Key Laboratory of Karst Environment, School of Life Sciences, Southwest University, Beibei, Chongqing 400715, China
| | - Xiangyu Fan
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of Education, Chongqing Municipal Key Laboratory of Karst Environment, School of Life Sciences, Southwest University, Beibei, Chongqing 400715, China; School of Biological Science and Technology, University of Jinan, Jinan 250022, China
| | - Qingyu Sun
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of Education, Chongqing Municipal Key Laboratory of Karst Environment, School of Life Sciences, Southwest University, Beibei, Chongqing 400715, China
| | - Yigang Tong
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
| | - Feiyang Zhao
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
| | - Shaozhen Xing
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
| | - Guangqian Pei
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
| | - Qiming Li
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of Education, Chongqing Municipal Key Laboratory of Karst Environment, School of Life Sciences, Southwest University, Beibei, Chongqing 400715, China
| | - Longxiang Xie
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of Education, Chongqing Municipal Key Laboratory of Karst Environment, School of Life Sciences, Southwest University, Beibei, Chongqing 400715, China
| | - Jianping Xie
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of Education, Chongqing Municipal Key Laboratory of Karst Environment, School of Life Sciences, Southwest University, Beibei, Chongqing 400715, China.
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