1
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Ichioka R, Kitazawa Y, Taguchi G, Shimosaka M. A novel N-acetylglucosamine-6-phosphate deacetylase that is essential for chitin utilization in the chitinolytic bacterium, Chitiniphilus shinanonensis. J Appl Microbiol 2024; 135:lxae117. [PMID: 38724455 DOI: 10.1093/jambio/lxae117] [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: 02/18/2024] [Revised: 05/01/2024] [Accepted: 05/07/2024] [Indexed: 05/23/2024]
Abstract
AIMS We aimed to investigate the function of an unidentified gene annotated as a PIG-L domain deacetylase (cspld) in Chitiniphilus shinanonensis SAY3. cspld was identified using transposon mutagenesis, followed by negatively selecting a mutant incapable of growing on chitin, a polysaccharide consisting of N-acetyl-d-glucosamine (GlcNAc). We focused on the physiological role of CsPLD protein in chitin utilization. METHODS AND RESULTS Recombinant CsPLD expressed in Escherichia coli exhibited GlcNAc-6-phosphate deacetylase (GPD) activity, which is involved in the metabolism of amino sugars. However, SAY3 possesses two genes (csnagA1 and csnagA2) in its genome that code for proteins whose primary sequences are homologous to those of typical GPDs. Recombinant CsNagA1 and CsNagA2 also exhibited GPD activity with 23 and 1.6% of catalytic efficiency (kcat/Km), respectively, compared to CsPLD. The gene-disrupted mutant, Δcspld was unable to grow on chitin or GlcNAc, whereas the three mutants, ΔcsnagA1, ΔcsnagA2, and ΔcsnagA1ΔcsnagA2 grew similarly to SAY3. The determination of GPD activity in the crude extracts of each mutant revealed that CsPLD is a major enzyme that accounts for almost all cellular activities. CONCLUSIONS Deacetylation of GlcNAc-6P catalyzed by CsPLD (but not by typical GPDs) is essential for the assimilation of chitin and its constituent monosaccharide, GlcNAc, as a carbon and energy source in C. shinanonensis.
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Affiliation(s)
- Ryotaro Ichioka
- Department of Applied Biology, Faculty of Textile Science and Technology, Shinshu University, 3-15-1, Tokida, Ueda, Nagano 386-8567, Japan
| | - Yuri Kitazawa
- Department of Applied Biology, Faculty of Textile Science and Technology, Shinshu University, 3-15-1, Tokida, Ueda, Nagano 386-8567, Japan
| | - Goro Taguchi
- Department of Applied Biology, Faculty of Textile Science and Technology, Shinshu University, 3-15-1, Tokida, Ueda, Nagano 386-8567, Japan
| | - Makoto Shimosaka
- Department of Applied Biology, Faculty of Textile Science and Technology, Shinshu University, 3-15-1, Tokida, Ueda, Nagano 386-8567, Japan
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2
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Chowdhury N, Naorem RS, Hazarika DJ, Goswami G, Dasgupta A, Bora SS, Boro RC, Barooah M. An oxalate decarboxylase-like cupin domain containing protein is involved in imparting acid stress tolerance in Bacillus amyloliquefaciens MBNC. World J Microbiol Biotechnol 2024; 40:64. [PMID: 38189984 DOI: 10.1007/s11274-023-03870-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Accepted: 12/09/2023] [Indexed: 01/09/2024]
Abstract
We report here the structural and functional properties of an oxalate decarboxylase (OxDC)-like cupin domain-containing protein of Bacillus amyloliquefaciens MBNC and its role in imparting tolerance to acid stress conditions. Quantitative real-time PCR (qPCR) analysis revealed 32-fold and 20-fold upregulation of the target gene [(OxDC')cupin] under acetic acid stress and hydrochloric acid stress, respectively, indicating its association with the acid stress response. Bacterial cells with targeted inactivation of the (OxDC')cupin gene using the pMUTIN4 vector system showed decreased growth and survival rate in acidic pH, with drastically reduced exopolysaccharide production. In Silico protein-protein interaction studies revealed seven genes (viz. glmS, nagA, nagB, tuaF, tuaF, gcvT, and ykgA) related to cell wall biosynthesis and biofilm production to interact with OxDC-like cupin domain containing protein. While all these seven genes were upregulated in B. amyloliquefaciens MBNC after 6 h of exposure to pH 4.5, the mutant cells containing the inactivated (OxDC')cupin gene displayed significantly lower expression (RQ: 0.001-0.02) (compared to the wild-type cells) in both neutral and acidic pH. Our results indicate that the OxDC-like cupin domain containing protein is necessary for cell wall biosynthesis and biofilm production in Bacillus amyloliquefaciens MBNC for survival in acid-stress conditions.
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Affiliation(s)
- Naimisha Chowdhury
- DBT - North East Centre for Agricultural Biotechnology, Assam Agricultural University, Jorhat, Assam, 785013, India
- Department of Agricultural Biotechnology, Assam Agricultural University, Jorhat, Assam, 785013, India
| | - Romen Singh Naorem
- Department of Agricultural Biotechnology, Assam Agricultural University, Jorhat, Assam, 785013, India
| | - Dibya Jyoti Hazarika
- DBT - North East Centre for Agricultural Biotechnology, Assam Agricultural University, Jorhat, Assam, 785013, India
| | - Gunajit Goswami
- DBT - North East Centre for Agricultural Biotechnology, Assam Agricultural University, Jorhat, Assam, 785013, India
| | - Abhisek Dasgupta
- DBT - North East Centre for Agricultural Biotechnology, Assam Agricultural University, Jorhat, Assam, 785013, India
| | - Sudipta Sankar Bora
- DBT - North East Centre for Agricultural Biotechnology, Assam Agricultural University, Jorhat, Assam, 785013, India
| | - Robin Chandra Boro
- Department of Agricultural Biotechnology, Assam Agricultural University, Jorhat, Assam, 785013, India
| | - Madhumita Barooah
- Department of Agricultural Biotechnology, Assam Agricultural University, Jorhat, Assam, 785013, India.
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3
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Zeng H, Cheng M, Liu J, Hu C, Lin S, Cui R, Li H, Ye W, Wang L, Huang W. Pyrimirhodomyrtone inhibits Staphylococcus aureus by affecting the activity of NagA. Biochem Pharmacol 2023; 210:115455. [PMID: 36780990 DOI: 10.1016/j.bcp.2023.115455] [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: 11/20/2022] [Revised: 02/08/2023] [Accepted: 02/09/2023] [Indexed: 02/13/2023]
Abstract
The epidemic of methicillin-resistant Staphylococcus aureus (MRSA) infections has created a critical health threat. The drug resistance of MRSA makes the development of drugs with new modes of action particularly urgent. In this study, we found that a natural product derivative pyrimirhodomyrtone (PRM) exerted antibacterial activity against S. aureus, including MRSA, both in vitro and in vivo. Genetic and biochemical studies revealed the interaction between PRM and N-acetylglucosamine-6-phosphate deacetylase (NagA) and the inhibitory effect of PRM on its deacetylation activity. We also found that PRM causes depolarization and destroys the integrity of the cell membrane. The elucidation of the antibacterial mechanism will inspire the subsequent development of new anti-MRSA drugs based on PRM.
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Affiliation(s)
- Huan Zeng
- Center for Bioactive Natural Molecules and Innovative Drugs Research, Guangdong Province Key Laboratory of Pharmacodynamic Constituents of TCM and New Drugs Research, College of Pharmacy, Jinan University, Guangzhou 511443, Guangdong, China; Shenzhen Institute of Respiratory Diseases, Shenzhen People's Hospital (The Second Clinical Medical College, Jinan University, The First Affiliated Hospital, Southern University of Science and Technology), Shenzhen 518020, China
| | - Minjing Cheng
- Center for Bioactive Natural Molecules and Innovative Drugs Research, Guangdong Province Key Laboratory of Pharmacodynamic Constituents of TCM and New Drugs Research, College of Pharmacy, Jinan University, Guangzhou 511443, Guangdong, China
| | - Jingyi Liu
- Department of Microbiology and Biochemical Pharmacy, National Engineering Research Center of Immunological Products, College of Pharmacy, Third Military Medical University, Chongqing 400038, China
| | - Chunxia Hu
- Shenzhen Institute of Respiratory Diseases, Shenzhen People's Hospital (The Second Clinical Medical College, Jinan University, The First Affiliated Hospital, Southern University of Science and Technology), Shenzhen 518020, China
| | - Shilin Lin
- Center for Bioactive Natural Molecules and Innovative Drugs Research, Guangdong Province Key Laboratory of Pharmacodynamic Constituents of TCM and New Drugs Research, College of Pharmacy, Jinan University, Guangzhou 511443, Guangdong, China
| | - Ruiqin Cui
- Shenzhen Institute of Respiratory Diseases, Shenzhen People's Hospital (The Second Clinical Medical College, Jinan University, The First Affiliated Hospital, Southern University of Science and Technology), Shenzhen 518020, China
| | - Haibo Li
- Department of Microbiology and Biochemical Pharmacy, National Engineering Research Center of Immunological Products, College of Pharmacy, Third Military Medical University, Chongqing 400038, China.
| | - Wencai Ye
- Center for Bioactive Natural Molecules and Innovative Drugs Research, Guangdong Province Key Laboratory of Pharmacodynamic Constituents of TCM and New Drugs Research, College of Pharmacy, Jinan University, Guangzhou 511443, Guangdong, China.
| | - Lei Wang
- Center for Bioactive Natural Molecules and Innovative Drugs Research, Guangdong Province Key Laboratory of Pharmacodynamic Constituents of TCM and New Drugs Research, College of Pharmacy, Jinan University, Guangzhou 511443, Guangdong, China.
| | - Wei Huang
- Shenzhen Institute of Respiratory Diseases, Shenzhen People's Hospital (The Second Clinical Medical College, Jinan University, The First Affiliated Hospital, Southern University of Science and Technology), Shenzhen 518020, China; Department of Clinical Microbiology, Shenzhen People's Hospital (The Second Clinical Medical College, Jinan University, The First Affiliated Hospital, Southern University of Science and Technology), Shenzhen 518020, China.
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4
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Roy S, Vivoli Vega M, Ames JR, Britten N, Kent A, Evans K, Isupov MN, Harmer NJ. The ROK kinase N-acetylglucosamine kinase uses a sequential random enzyme mechanism with successive conformational changes upon each substrate binding. J Biol Chem 2023; 299:103033. [PMID: 36806680 PMCID: PMC10031466 DOI: 10.1016/j.jbc.2023.103033] [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: 11/10/2022] [Revised: 02/10/2023] [Accepted: 02/11/2023] [Indexed: 02/18/2023] Open
Abstract
N-acetyl-d-glucosamine (GlcNAc) is a major component of bacterial cell walls. Many organisms recycle GlcNAc from the cell wall or metabolize environmental GlcNAc. The first step in GlcNAc metabolism is phosphorylation to GlcNAc-6-phosphate. In bacteria, the ROK family kinase N-acetylglucosamine kinase (NagK) performs this activity. Although ROK kinases have been studied extensively, no ternary complex showing the two substrates has yet been observed. Here, we solved the structure of NagK from the human pathogen Plesiomonas shigelloides in complex with GlcNAc and the ATP analog AMP-PNP. Surprisingly, PsNagK showed distinct conformational changes associated with the binding of each substrate. Consistent with this, the enzyme showed a sequential random enzyme mechanism. This indicates that the enzyme acts as a coordinated unit responding to each interaction. Our molecular dynamics modeling of catalytic ion binding confirmed the location of the essential catalytic metal. Additionally, site-directed mutagenesis confirmed the catalytic base and that the metal-coordinating residue is essential. Together, this study provides the most comprehensive insight into the activity of a ROK kinase.
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Affiliation(s)
| | | | | | | | - Amy Kent
- Living Systems Institute, Exeter, UK
| | - Kim Evans
- Living Systems Institute, Exeter, UK
| | - Michail N Isupov
- Henry Wellcome Building for Biocatalysis, Biosciences, Exeter, UK
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5
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Kroef V, Ruegenberg S, Horn M, Allmeroth K, Ebert L, Bozkus S, Miethe S, Elling U, Schermer B, Baumann U, Denzel MS. GFPT2/GFAT2 and AMDHD2 act in tandem to control the hexosamine pathway. eLife 2022; 11:69223. [PMID: 35229715 PMCID: PMC8970586 DOI: 10.7554/elife.69223] [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: 04/08/2021] [Accepted: 02/28/2022] [Indexed: 11/25/2022] Open
Abstract
The hexosamine biosynthetic pathway (HBP) produces the essential metabolite UDP-GlcNAc and plays a key role in metabolism, health, and aging. The HBP is controlled by its rate-limiting enzyme glutamine fructose-6-phosphate amidotransferase (GFPT/GFAT) that is directly inhibited by UDP-GlcNAc in a feedback loop. HBP regulation by GFPT is well studied but other HBP regulators have remained obscure. Elevated UDP-GlcNAc levels counteract the glycosylation toxin tunicamycin (TM), and thus we screened for TM resistance in haploid mouse embryonic stem cells (mESCs) using random chemical mutagenesis to determine alternative HBP regulation. We identified the N-acetylglucosamine deacetylase AMDHD2 that catalyzes a reverse reaction in the HBP and its loss strongly elevated UDP-GlcNAc. To better understand AMDHD2, we solved the crystal structure and found that loss-of-function (LOF) is caused by protein destabilization or interference with its catalytic activity. Finally, we show that mESCs express AMDHD2 together with GFPT2 instead of the more common paralog GFPT1. Compared with GFPT1, GFPT2 had a much lower sensitivity to UDP-GlcNAc inhibition, explaining how AMDHD2 LOF resulted in HBP activation. This HBP configuration in which AMDHD2 serves to balance GFPT2 activity was also observed in other mESCs and, consistently, the GFPT2:GFPT1 ratio decreased with differentiation of human embryonic stem cells. Taken together, our data reveal a critical function of AMDHD2 in limiting UDP-GlcNAc production in cells that use GFPT2 for metabolite entry into the HBP.
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Affiliation(s)
- Virginia Kroef
- Molecular Genetics of Ageing, Max Planck Institute for Biology of Ageing, Cologne, Germany
| | - Sabine Ruegenberg
- Molecular Genetics of Ageing, Max Planck Institute for Biology of Ageing, Cologne, Germany
| | | | - Kira Allmeroth
- Molecular Genetics of Ageing, Max Planck Institute for Biology of Ageing, Cologne, Germany
| | | | | | - Stephan Miethe
- Molecular Genetics of Ageing, Max Planck Institute for Biology of Ageing, Cologne, Germany
| | - Ulrich Elling
- Vienna Biocenter, Austrian Academy of Sciences, Vienna, Austria
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6
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Gray J, Chandry PS, Kaur M, Kocharunchitt C, Fanning S, Bowman JP, Fox EM. Colonisation dynamics of Listeria monocytogenes strains isolated from food production environments. Sci Rep 2021; 11:12195. [PMID: 34108547 PMCID: PMC8190317 DOI: 10.1038/s41598-021-91503-w] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Accepted: 05/06/2021] [Indexed: 12/19/2022] Open
Abstract
Listeria monocytogenes is a ubiquitous bacterium capable of colonising and persisting within food production environments (FPEs) for many years, even decades. This ability to colonise, survive and persist within the FPEs can result in food product cross-contamination, including vulnerable products such as ready to eat food items. Various environmental and genetic elements are purported to be involved, with the ability to form biofilms being an important factor. In this study we examined various mechanisms which can influence colonisation in FPEs. The ability of isolates (n = 52) to attach and grow in biofilm was assessed, distinguishing slower biofilm formers from isolates forming biofilm more rapidly. These isolates were further assessed to determine if growth rate, exopolymeric substance production and/or the agr signalling propeptide influenced these dynamics and could promote persistence in conditions reflective of FPE. Despite no strong association with the above factors to a rapid colonisation phenotype, the global transcriptome suggested transport, energy production and metabolism genes were widely upregulated during the initial colonisation stages under nutrient limited conditions. However, the upregulation of the metabolism systems varied between isolates supporting the idea that L. monocytogenes ability to colonise the FPEs is strain-specific.
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Affiliation(s)
- Jessica Gray
- CSIRO Agriculture and Food, Werribee, VIC, Australia. .,Food Safety Centre, Tasmanian Institute of Agriculture, School of Land and Food, University of Tasmania, Hobart, TAS, Australia.
| | | | - Mandeep Kaur
- Biosciences and Food Technology, School of Science, RMIT University, Melbourne, VIC, Australia
| | - Chawalit Kocharunchitt
- Food Safety Centre, Tasmanian Institute of Agriculture, School of Land and Food, University of Tasmania, Hobart, TAS, Australia
| | - Séamus Fanning
- UCD-Centre for Food Safety, School of Public Health, Physiotherapy and Sports Science, University College Dublin, Dublin, D04 N2E5, Ireland.,Institute for Global Food Security, Queen's University Belfast, Chlorine Gardens, Belfast, BT5 6AG, UK
| | - John P Bowman
- Food Safety Centre, Tasmanian Institute of Agriculture, School of Land and Food, University of Tasmania, Hobart, TAS, Australia
| | - Edward M Fox
- CSIRO Agriculture and Food, Werribee, VIC, Australia. .,Department of Applied Sciences, Northumbria University, Newcastle upon Tyne, NE1 8ST, UK.
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7
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Nikparvar B, Andreevskaya M, Duru IC, Bucur FI, Grigore-Gurgu L, Borda D, Nicolau AI, Riedel CU, Auvinen P, Bar N. Analysis of temporal gene regulation of Listeria monocytogenes revealed distinct regulatory response modes after exposure to high pressure processing. BMC Genomics 2021; 22:266. [PMID: 33853520 PMCID: PMC8045354 DOI: 10.1186/s12864-021-07461-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Accepted: 02/10/2021] [Indexed: 01/16/2023] Open
Abstract
BACKGROUND The pathogen Listeria (L.) monocytogenes is known to survive heat, cold, high pressure, and other extreme conditions. Although the response of this pathogen to pH, osmotic, temperature, and oxidative stress has been studied extensively, its reaction to the stress produced by high pressure processing HPP (which is a preservation method in the food industry), and the activated gene regulatory network (GRN) in response to this stress is still largely unknown. RESULTS We used RNA sequencing transcriptome data of L. monocytogenes (ScottA) treated at 400 MPa and 8∘C, for 8 min and combined it with current information in the literature to create a transcriptional regulation database, depicting the relationship between transcription factors (TFs) and their target genes (TGs) in L. monocytogenes. We then applied network component analysis (NCA), a matrix decomposition method, to reconstruct the activities of the TFs over time. According to our findings, L. monocytogenes responded to the stress applied during HPP by three statistically different gene regulation modes: survival mode during the first 10 min post-treatment, repair mode during 1 h post-treatment, and re-growth mode beyond 6 h after HPP. We identified the TFs and their TGs that were responsible for each of the modes. We developed a plausible model that could explain the regulatory mechanism that L. monocytogenes activated through the well-studied CIRCE operon via the regulator HrcA during the survival mode. CONCLUSIONS Our findings suggest that the timely activation of TFs associated with an immediate stress response, followed by the expression of genes for repair purposes, and then re-growth and metabolism, could be a strategy of L. monocytogenes to survive and recover extreme HPP conditions. We believe that our results give a better understanding of L. monocytogenes behavior after exposure to high pressure that may lead to the design of a specific knock-out process to target the genes or mechanisms. The results can help the food industry select appropriate HPP conditions to prevent L. monocytogenes recovery during food storage.
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Affiliation(s)
- Bahareh Nikparvar
- Department of Chemical Engineering, Norwegian University of Science and Technology, Trondheim, Norway
| | | | - Ilhan C Duru
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Florentina I Bucur
- Faculty of Food Science and Engineering, Dunarea de Jos University of Galati, Galati, Romania
| | - Leontina Grigore-Gurgu
- Faculty of Food Science and Engineering, Dunarea de Jos University of Galati, Galati, Romania
| | - Daniela Borda
- Faculty of Food Science and Engineering, Dunarea de Jos University of Galati, Galati, Romania
| | - Anca I Nicolau
- Faculty of Food Science and Engineering, Dunarea de Jos University of Galati, Galati, Romania
| | - Christian U Riedel
- Institute of Microbiology and Biotechnology, Ulm University, Ulm, Germany
| | - Petri Auvinen
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Nadav Bar
- Department of Chemical Engineering, Norwegian University of Science and Technology, Trondheim, Norway.
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8
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Duru IC, Bucur FI, Andreevskaya M, Nikparvar B, Ylinen A, Grigore-Gurgu L, Rode TM, Crauwels P, Laine P, Paulin L, Løvdal T, Riedel CU, Bar N, Borda D, Nicolau AI, Auvinen P. High-pressure processing-induced transcriptome response during recovery of Listeria monocytogenes. BMC Genomics 2021; 22:117. [PMID: 33579201 PMCID: PMC7881616 DOI: 10.1186/s12864-021-07407-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 01/25/2021] [Indexed: 12/18/2022] Open
Abstract
Background High-pressure processing (HPP) is a commonly used technique in the food industry to inactivate pathogens, including L. monocytogenes. It has been shown that L. monocytogenes is able to recover from HPP injuries and can start to grow again during long-term cold storage. To date, the gene expression profiling of L. monocytogenes during HPP damage recovery at cooling temperature has not been studied. In order identify key genes that play a role in recovery of the damage caused by HPP treatment, we performed RNA-sequencing (RNA-seq) for two L. monocytogenes strains (barotolerant RO15 and barosensitive ScottA) at nine selected time points (up to 48 h) after treatment with two pressure levels (200 and 400 MPa). Results The results showed that a general stress response was activated by SigB after HPP treatment. In addition, the phosphotransferase system (PTS; mostly fructose-, mannose-, galactitol-, cellobiose-, and ascorbate-specific PTS systems), protein folding, and cobalamin biosynthesis were the most upregulated genes during HPP damage recovery. We observed that cell-division-related genes (divIC, dicIVA, ftsE, and ftsX) were downregulated. By contrast, peptidoglycan-synthesis genes (murG, murC, and pbp2A) were upregulated. This indicates that cell-wall repair occurs as a part of HPP damage recovery. We also observed that prophage genes, including anti-CRISPR genes, were induced by HPP. Interestingly, a large amount of RNA-seq data (up to 85%) was mapped to Rli47, which is a non-coding RNA that is upregulated after HPP. Thus, we predicted that Rli47 plays a role in HPP damage recovery in L. monocytogenes. Moreover, gene-deletion experiments showed that amongst peptidoglycan biosynthesis genes, pbp2A mutants are more sensitive to HPP. Conclusions We identified several genes and mechanisms that may play a role in recovery from HPP damage of L. monocytogenes. Our study contributes to new information on pathogen inactivation by HPP. Supplementary Information The online version contains supplementary material available at 10.1186/s12864-021-07407-6.
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Affiliation(s)
- Ilhan Cem Duru
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland.
| | - Florentina Ionela Bucur
- Faculty of Food Science and Engineering, Dunarea de Jos University of Galati, Galati, Romania
| | | | - Bahareh Nikparvar
- Department of Chemical Engineering, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Anne Ylinen
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Leontina Grigore-Gurgu
- Faculty of Food Science and Engineering, Dunarea de Jos University of Galati, Galati, Romania
| | - Tone Mari Rode
- Department of Process Technology, Nofima - Norwegian Institute of Food, Fisheries and Aquaculture Research, N-4068, Stavanger, Norway
| | - Peter Crauwels
- Institute of Microbiology and Biotechnology, Ulm, University, Albert-Einstein-Allee 11, D-89081, Ulm, Germany
| | - Pia Laine
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Lars Paulin
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Trond Løvdal
- Department of Process Technology, Nofima - Norwegian Institute of Food, Fisheries and Aquaculture Research, N-4068, Stavanger, Norway
| | - Christian U Riedel
- Institute of Microbiology and Biotechnology, Ulm, University, Albert-Einstein-Allee 11, D-89081, Ulm, Germany
| | - Nadav Bar
- Department of Chemical Engineering, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Daniela Borda
- Faculty of Food Science and Engineering, Dunarea de Jos University of Galati, Galati, Romania
| | - Anca Ioana Nicolau
- Faculty of Food Science and Engineering, Dunarea de Jos University of Galati, Galati, Romania
| | - Petri Auvinen
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
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9
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Villoria Recio M, Lee BH, Lillebæk EMS, Kallipolitis BH, Gahan CGM, Ingmer H, Larsen MH. Chitin Attenuates Expression of Listeria monocytogenes Virulence Genes in vitro. Front Microbiol 2020; 11:588906. [PMID: 33343529 PMCID: PMC7744463 DOI: 10.3389/fmicb.2020.588906] [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] [Received: 07/29/2020] [Accepted: 11/12/2020] [Indexed: 11/13/2022] Open
Abstract
External signals are crucial for bacteria to sense their immediate environment and fine-tune gene expression accordingly. The foodborne pathogen Listeria monocytogenes senses a range of environmental cues in order to activate or deactivate the virulence-inducing transcriptional factor PrfA during transition between infectious and saprophytic lifecycles. Chitin is an abundant biopolymer formed from linked β-(1-4)-N-acetyl-D-glucosamine residues associated with fungi, the exoskeleton of insects and often incorporated into foods as a thickener or stabilizer. L. monocytogenes evolved to hydrolyse chitin, presumably, to facilitate nutrient acquisition from competitive environments such as soil where the polymer is abundant. Since mammals do not produce chitin, we reasoned that the polymer could serve as an environmental signal contributing to repression of L. monocytogenes PrfA-dependent expression. This study shows a significant downregulation of the core PrfA-regulon during virulence-inducing conditions in vitro in the presence of chitin. Our data suggest this phenomenon occurs through a mechanism that differs from PTS-transport of oligosaccharides generated from either degradation or chitinase-mediated hydrolysis of the polymer. Importantly, an indication that chitin can repress virulence expression of a constitutively active PrfA∗ mutant is shown, possibly mediated via a post-translational modification inhibiting PrfA∗ activity. To our knowledge, this is the first time that chitin is reported as a molecule with anti-virulence properties against a pathogenic bacterium. Thus, our findings identify chitin as a signal which may downregulate the virulence potential of the pathogen and may provide an alternative approach toward reducing disease risk.
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Affiliation(s)
- Miguel Villoria Recio
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, Food Safety and Zoonoses-University of Copenhagen, Frederiksberg, Denmark.,Alimentary Pharmabotic Centre Microbiome Ireland, University College Cork, Cork, Ireland.,School of Microbiology, University College Cork, Cork, Ireland
| | - Bo-Hyung Lee
- Université Paris-Saclay, INRAE, UVSQ, VIM, Jouy-en-Josas, France
| | | | - Birgitte H Kallipolitis
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
| | - Cormac G M Gahan
- Alimentary Pharmabotic Centre Microbiome Ireland, University College Cork, Cork, Ireland.,School of Microbiology, University College Cork, Cork, Ireland
| | - Hanne Ingmer
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, Food Safety and Zoonoses-University of Copenhagen, Frederiksberg, Denmark
| | - Marianne Halberg Larsen
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, Food Safety and Zoonoses-University of Copenhagen, Frederiksberg, Denmark
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10
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Wambui J, Eshwar AK, Aalto-Araneda M, Pöntinen A, Stevens MJA, Njage PMK, Tasara T. The Analysis of Field Strains Isolated From Food, Animal and Clinical Sources Uncovers Natural Mutations in Listeria monocytogenes Nisin Resistance Genes. Front Microbiol 2020; 11:549531. [PMID: 33123101 PMCID: PMC7574537 DOI: 10.3389/fmicb.2020.549531] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Accepted: 09/02/2020] [Indexed: 12/19/2022] Open
Abstract
Nisin is a commonly used bacteriocin for controlling spoilage and pathogenic bacteria in food products. Strains possessing high natural nisin resistance that reduce or increase the potency of this bacteriocin against Listeria monocytogenes have been described. Our study sought to gather more insights into nisin resistance mechanisms in natural L. monocytogenes populations by examining a collection of 356 field strains that were isolated from different foods, food production environments, animals and human infections. A growth curve analysis-based approach was used to access nisin inhibition levels and assign the L. monocytogenes strains into three nisin response phenotypic categories; resistant (66%), intermediate (26%), and sensitive (8%). Using this categorization isolation source, serotype, genetic lineage, clonal complex (CC) and strain-dependent natural variation in nisin phenotypic resistance among L. monocytogenes field strains was revealed. Whole genome sequence analysis and comparison of high nisin resistant and sensitive strains led to the identification of new naturally occurring mutations in nisin response genes associated with increased nisin resistance and sensitivity in this bacterium. Increased nisin resistance was detected in strains harboring RsbUG77S and PBPB3V240F amino acid substitution mutations, which also showed increased detergent stress resistance as well as increased virulence in a zebra fish infection model. On the other hand, increased natural nisin sensitivity was detected among strains with mutations in sigB, vir, and dlt operons that also showed increased lysozyme sensitivity and lower virulence. Overall, our study identified naturally selected mutations involving pbpB3 (lm0441) as well as sigB, vir, and dlt operon genes that are associated with intrinsic nisin resistance in L. monocytogenes field strains recovered from various food and human associated sources. Finally, we show that combining growth parameter-based phenotypic analysis and genome sequencing is an effective approach that can be useful for the identification of novel nisin response associated genetic variants among L. monocytogenes field strains.
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Affiliation(s)
- Joseph Wambui
- Institute for Food Safety and Hygiene, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland.,Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | - Athmanya K Eshwar
- Institute for Food Safety and Hygiene, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland
| | - Mariella Aalto-Araneda
- Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland
| | - Anna Pöntinen
- Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland
| | - Marc J A Stevens
- Institute for Food Safety and Hygiene, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland
| | - Patrick M K Njage
- Research Group for Genomic Epidemiology, Division for Global Surveillance, National Food Institute, Technical University of Denmark, Kengens Lyngby, Denmark
| | - Taurai Tasara
- Institute for Food Safety and Hygiene, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland
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11
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Manjunath L, Coombes D, Davies J, Dhurandhar M, Tiwari VR, Dobson RCJ, Sowdhamini R, Ramaswamy S, Bose S. Quaternary variations in the structural assembly of N-acetylglucosamine-6-phosphate deacetylase from Pasteurella multocida. Proteins 2020; 89:81-93. [PMID: 32865821 DOI: 10.1002/prot.25996] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 07/14/2020] [Accepted: 08/25/2020] [Indexed: 12/13/2022]
Abstract
N-acetylglucosamine 6-phosphate deacetylase (NagA) catalyzes the conversion of N-acetylglucosamine-6-phosphate to glucosamine-6-phosphate in amino sugar catabolism. This conversion is an essential step in the catabolism of sialic acid in several pathogenic bacteria, including Pasteurella multocida, and thus NagA is identified as a potential drug target. Here, we report the unique structural features of NagA from P. multocida (PmNagA) resolved to 1.95 Å. PmNagA displays an altered quaternary architecture with unique interface interactions compared to its close homolog, the Escherichia coli NagA (EcNagA). We confirmed that the altered quaternary structure is not a crystallographic artifact using single particle electron cryo-microscopy. Analysis of the determined crystal structure reveals a set of hot-spot residues involved in novel interactions at the dimer-dimer interface. PmNagA binds to one Zn2+ ion in the active site and demonstrates kinetic parameters comparable to other bacterial homologs. Kinetic studies reveal that at high substrate concentrations (~10-fold the KM ), the tetrameric PmNagA displays hysteresis similar to its distant neighbor, the dimeric Staphylococcus aureus NagA (SaNagA). Our findings provide key information on structural and functional properties of NagA in P. multocida that could be utilized to design novel antibacterials.
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Affiliation(s)
- Lavanyaa Manjunath
- Institute for Stem Cell Science and Regenerative Medicine, NCBS, GKVK Campus, Bangalore, Karnataka, India
- Manipal Academy of Higher Education, Tiger Circle, Manipal, Karnataka, India
| | - David Coombes
- Biomolecular Interaction Centre and School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
| | - James Davies
- Biomolecular Interaction Centre and School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
| | - Mugdha Dhurandhar
- National Centre for Biological Sciences, GKVK Campus, Bangalore, Karnataka, India
| | - Vikas R Tiwari
- National Centre for Biological Sciences, GKVK Campus, Bangalore, Karnataka, India
| | - Renwick C J Dobson
- Biomolecular Interaction Centre and School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
- Bio21 Molecular Science and Biotechnology Institute, Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, Victoria, Australia
| | - R Sowdhamini
- National Centre for Biological Sciences, GKVK Campus, Bangalore, Karnataka, India
| | - S Ramaswamy
- Institute for Stem Cell Science and Regenerative Medicine, NCBS, GKVK Campus, Bangalore, Karnataka, India
- Department of Biological Sciences and Department of Biomedical Engineering, Purdue University, West Lafayette, Indiana, USA
| | - Sucharita Bose
- Institute for Stem Cell Science and Regenerative Medicine, NCBS, GKVK Campus, Bangalore, Karnataka, India
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12
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Adewumi AT, Ramharack P, Soremekun OS, Soliman MES. Delving into the Characteristic Features of "Menace" Mycobacterium tuberculosis Homologs: A Structural Dynamics and Proteomics Perspectives. Protein J 2020; 39:118-132. [PMID: 32162114 DOI: 10.1007/s10930-020-09890-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The global increase in the morbidity/mortality rate of Mycobacterial infections, predominantly renascent tuberculosis, leprosy, and Buruli ulcers have become worrisome over the years. More challenging is the incidence of resistance mediated by mutant Mycobacterium strains against front-line antitubercular drugs. Homologous to all Mycobacteria species is the GlcNAc-6-phosphate deacetylase (NagA) which catalyzes essential amino sugars synthesis required for cell wall architecture, hence, metamorphosing into an important pharmacological target for curtailing virulence and drug-resistance. This study used integrated bioinformatics methods, MD simulations, and DynaMut and PolyPhen2 to; explore unique features, monitor dynamics, and analyze the functional impact of non-synonymous single-nucleotide polymorphisms of the six NagA of most ruinous Mycobacterium species; tuberculosis (Mtb), smegmatis (MS), marinum (MM), ulcerans, africanum, and microti respectively. This approach is essential for multi-targeting and could result in the identification of potential polypharmacological antitubercular compounds. Comparative sequential analyses revealed ≤ 50% of the overall structure, including the catalytic Asp267 and reactive Cys131, remained conserved. Interestingly, MS-NagA and MM-NagA possess unique hydrophobic isoleucine (Ile) residues at their active sites in contrast to leucine (Leu) found in other variants. More so, unique to the active sites of the NagA is a 'subunit loop' that covers the active site; probably crucial in binding (entry and exit) mechanisms of targeted NagA inhibitors. Relatively, nsSNP mutations exerted a destabilizing effect on the native NagA conformation. Structural and dynamical insights provided, basically pin-pointed the "Achilles' heel" explorable for the rational drug design of target-specific 'NagA' inhibitors potent against a wide range of mycobacterial diseases.
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Affiliation(s)
- Adeniyi T Adewumi
- Molecular Bio-computation and Drug Design Laboratory, School of Health Sciences, University of KwaZulu-Natal, Westville Campus, Durban, 4001, South Africa
| | - Pritika Ramharack
- Molecular Bio-computation and Drug Design Laboratory, School of Health Sciences, University of KwaZulu-Natal, Westville Campus, Durban, 4001, South Africa
| | - Opeyemi S Soremekun
- Molecular Bio-computation and Drug Design Laboratory, School of Health Sciences, University of KwaZulu-Natal, Westville Campus, Durban, 4001, South Africa
| | - Mahmoud E S Soliman
- Molecular Bio-computation and Drug Design Laboratory, School of Health Sciences, University of KwaZulu-Natal, Westville Campus, Durban, 4001, South Africa.
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Liu Y, Orsi RH, Gaballa A, Wiedmann M, Boor KJ, Guariglia-Oropeza V. Systematic review of the Listeria monocytogenes σB regulon supports a role in stress response, virulence and metabolism. Future Microbiol 2019; 14:801-828. [DOI: 10.2217/fmb-2019-0072] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Aim: Among the alternative sigma factors of Listeria monocytogenes, σB controls the largest regulon. The aim of this study was to perform a comprehensive review of σB-regulated genes, and the functions they confer. Materials & methods: A systematic search of PubMed and Web of Knowledge was carried out to identify members of the σB regulon based on experimental evidence of σB-dependent transcription and presence of a consensus σB-dependent promoter. Results: The literature review identified σB-dependent transcription units encompassing 304 genes encoding different functions including stress response and virulence. Conclusion: Our review supports the well-known roles of σB in virulence and stress response and provides new insight into novel roles for σB in metabolism and overall resilience of L. monocytogenes.
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Affiliation(s)
- Yichang Liu
- Department of Food Science, Cornell University, Ithaca, NY 14850, USA
| | - Renato H Orsi
- Department of Food Science, Cornell University, Ithaca, NY 14850, USA
| | - Ahmed Gaballa
- Department of Food Science, Cornell University, Ithaca, NY 14850, USA
| | - Martin Wiedmann
- Department of Food Science, Cornell University, Ithaca, NY 14850, USA
| | - Kathryn J Boor
- Department of Food Science, Cornell University, Ithaca, NY 14850, USA
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Resilience in the Face of Uncertainty: Sigma Factor B Fine-Tunes Gene Expression To Support Homeostasis in Gram-Positive Bacteria. Appl Environ Microbiol 2016; 82:4456-4469. [PMID: 27208112 DOI: 10.1128/aem.00714-16] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Gram-positive bacteria are ubiquitous and diverse microorganisms that can survive and sometimes even thrive in continuously changing environments. The key to such resilience is the ability of members of a population to respond and adjust to dynamic conditions in the environment. In bacteria, such responses and adjustments are mediated, at least in part, through appropriate changes in the bacterial transcriptome in response to the conditions encountered. Resilience is important for bacterial survival in diverse, complex, and rapidly changing environments and requires coordinated networks that integrate individual, mechanistic responses to environmental cues to enable overall metabolic homeostasis. In many Gram-positive bacteria, a key transcriptional regulator of the response to changing environmental conditions is the alternative sigma factor σ(B) σ(B) has been characterized in a subset of Gram-positive bacteria, including the genera Bacillus, Listeria, and Staphylococcus Recent insight from next-generation-sequencing results indicates that σ(B)-dependent regulation of gene expression contributes to resilience, i.e., the coordination of complex networks responsive to environmental changes. This review explores contributions of σ(B) to resilience in Bacillus, Listeria, and Staphylococcus and illustrates recently described regulatory functions of σ(B).
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15
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Krawczyk-Balska A, Korsak D, Popowska M. The surface protein Lmo1941 with LysM domain influences cell wall structure and susceptibility of Listeria monocytogenes to cephalosporins. FEMS Microbiol Lett 2014; 357:175-83. [PMID: 24974853 DOI: 10.1111/1574-6968.12518] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2014] [Revised: 06/04/2014] [Accepted: 06/20/2014] [Indexed: 11/30/2022] Open
Abstract
Listeria monocytogenes is a Gram-positive bacterium causing rare but dangerous cases of disease in humans and animals. The β-lactams penicillin G and ampicillin are the antibiotics of choice in the treatment of listeriosis. Recently, lmo1941, encoding a surface protein of L. monocytogenes with unknown function, was identified as a gene transcriptionally upregulated under penicillin G pressure. In this study, the effect of lmo1941 knockout on the susceptibility of L. monocytogenes to β-lactams was examined. Deletion mutant in lmo1941 was constructed and subjected to studies, which revealed that the deletion of lmo1941 had no effect on susceptibility and tolerance to penicillin G and ampicillin but resulted, however, in increased susceptibility of L. monocytogenes to several cephalosporins. Subsequently, the potential effect of lmo1941 mutation on the cell wall of L. monocytogenes was investigated. The analysis revealed quantitative changes in the muropeptide profile of peptidoglycan and a decrease in density of the high-density zone of cell wall of the mutant strain. Both these changes were observed in cells taken from the stationary phase. These results indicate that the surface protein Lmo1941 affects peptidoglycan composition and cell wall structure of L. monocytogenes in the stationary phase of growth.
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Affiliation(s)
- Agata Krawczyk-Balska
- Faculty of Biology, Department of Applied Microbiology, Institute of Microbiology, University of Warsaw, Warsaw, Poland
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16
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Yang S, Zhang F, Kang J, Zhang W, Deng G, Xin Y, Ma Y. Mycobacterium tuberculosis Rv1096 protein: gene cloning, protein expression, and peptidoglycan deacetylase activity. BMC Microbiol 2014; 14:174. [PMID: 24975018 PMCID: PMC4087242 DOI: 10.1186/1471-2180-14-174] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2014] [Accepted: 06/25/2014] [Indexed: 01/26/2023] Open
Abstract
Background Many bacteria modulate and evade the immune defenses of their hosts through peptidoglycan (PG) deacetylation. The PG deacetylases from Streptococcus pneumonia, Listeria monocytogenes and Lactococcus lactis have been characterized. However, thus far, the PG deacetylase of Mycobacterium tuberculosis has not been identified. Results In this study, we cloned the Rv1096 gene from the M. tuberculosis H37Rv strain and expressed Rv1096 protein in both Escherichia coli and M. smegmatis. The results showed that the purified Rv1096 protein possessed metallo-dependent PG deacetylase activity, which increased in the presence of Co2+. The kinetic parameters of the PG deacetylase towards M. smegmatis PG as a substrate were as follows: Km, 0.910 ± 0.007 mM; Vmax, 0.514 ± 0.038 μMmin-1; and Kcat = 0.099 ± 0.007 (S-1). Additionally, the viability of M. smegmatis in the presence of over-expressed Rv1096 protein was 109-fold higher than that of wild-type M. smegmatis after lysozyme treatment. Additionally, light microscopy and scanning electron microscopy showed that in the presence of over-expressed Rv1096 protein, M. smegmatis kept its regular shape, with an undamaged cell wall and smooth surface. These results indicate that Rv1096 caused deacetylation of cell wall PG, leading to lysozyme resistance in M. smegmatis. Conclusion We have determined that M. tuberculosis Rv1096 is a PG deacetylase. The PG deacetylase activity of Rv1096 contributed to lysozyme resistance in M. smegmatis. Our findings suggest that deacetylation of cell wall PG may be involved in evasion of host immune defenses by M. tuberculosis.
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Affiliation(s)
| | | | | | | | | | | | - Yufang Ma
- Department of Biochemistry and Molecular Biology, Dalian Medical University, 9 W Lushun South Road, Dalian 116044, China.
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Guariglia-Oropeza V, Orsi RH, Yu H, Boor KJ, Wiedmann M, Guldimann C. Regulatory network features in Listeria monocytogenes-changing the way we talk. Front Cell Infect Microbiol 2014; 4:14. [PMID: 24592357 PMCID: PMC3924034 DOI: 10.3389/fcimb.2014.00014] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2013] [Accepted: 01/27/2014] [Indexed: 01/04/2023] Open
Abstract
Our understanding of how pathogens shape their gene expression profiles in response to environmental changes is ever growing. Advances in Bioinformatics have made it possible to model complex systems and integrate data from variable sources into one large regulatory network. In these analyses, regulatory networks are typically broken down into regulatory motifs such as feed-forward loops (FFL) or auto-regulatory feedbacks, which serves to simplify the structure, while the functional implications of different regulatory motifs allow to make informed assumptions about the function of a specific regulatory pathway. Here we review the basic concepts of network features and use this language to break down the regulatory networks that govern the interactions between the main regulators of stress response, virulence, and transmission in Listeria monocytogenes. We point out the advantage that taking a “systems approach” could have for our understanding of gene functions, the detection of distant regulatory inputs, interspecies comparisons, and co-expression.
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Affiliation(s)
| | - Renato H Orsi
- Department of Food Science, Cornell University Ithaca, NY, USA
| | - Haiyuan Yu
- Department of Biological Statistics and Computational Biology, Cornell University Ithaca, NY, USA ; Department of Biological Statistics and Computational Biology, Weill Institute for Cell and Molecular Biology, Cornell University Ithaca, NY, USA
| | - Kathryn J Boor
- Department of Food Science, Cornell University Ithaca, NY, USA
| | - Martin Wiedmann
- Department of Food Science, Cornell University Ithaca, NY, USA
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Krawczyk-Balska A, Lipiak M. Critical role of a ferritin-like protein in the control of Listeria monocytogenes cell envelope structure and stability under β-lactam pressure. PLoS One 2013; 8:e77808. [PMID: 24204978 PMCID: PMC3812014 DOI: 10.1371/journal.pone.0077808] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2013] [Accepted: 09/05/2013] [Indexed: 02/08/2023] Open
Abstract
The human pathogen Listeria monocytogenes is susceptible to the β-lactam antibiotics penicillin G and ampicillin, and these are the drugs of choice for the treatment of listerial infections. However, these antibiotics exert only a bacteriostatic effect on this bacterium and consequently, L. monocytogenes is regarded as β-lactam tolerant. It is widely accepted that the phenomenon of bacterial tolerance to β-lactams is due to the lack of adequate autolysin activity, but the mechanisms of L. monocytogenes tolerance to this class of antibiotics are poorly characterized. A ferritin-like protein (Fri) was recently identified as a mediator of β-lactam tolerance in L. monocytogenes, but its function in this process remains unknown. The present study was undertaken to improve our understanding of L. monocytogenes tolerance to β-lactams and to characterize the role of Fri in this phenomenon. A comparative physiological analysis of wild-type L. monocytogenes and a fri deletion mutant provided evidence of a multilevel mechanism controlling autolysin activity in cells grown under β-lactam pressure, which leads to a reduction in the level and/or activity of cell wall-associated autolysins. This is accompanied by increases in the amount of teichoic acids, cell wall thickness and cell envelope integrity of L. monocytogenes grown in the presence of penicillin G, and provides the basis for the innate β-lactam tolerance of this bacterium. Furthermore, this study revealed the inability of the L. monocytogenes Δ fri mutant to deplete autolysins from the cell wall, to adjust the content of teichoic acids and to maintain their D-alanylation at the correct level when treated with penicillin G, thus providing further evidence that Fri is involved in the control of L. monocytogenes cell envelope structure and stability under β-lactam pressure.
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Affiliation(s)
- Agata Krawczyk-Balska
- Department of Applied Microbiology, Faculty of Biology, University of Warsaw, Warsaw, Poland
| | - Magdalena Lipiak
- Department of Applied Microbiology, Faculty of Biology, University of Warsaw, Warsaw, Poland
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Transcriptomic profiling of diverse Aedes aegypti strains reveals increased basal-level immune activation in dengue virus-refractory populations and identifies novel virus-vector molecular interactions. PLoS Negl Trop Dis 2013; 7:e2295. [PMID: 23861987 PMCID: PMC3701703 DOI: 10.1371/journal.pntd.0002295] [Citation(s) in RCA: 121] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2013] [Accepted: 05/21/2013] [Indexed: 01/23/2023] Open
Abstract
Genetic variation among Aedes aegypti populations can greatly influence their vector competence for human pathogens such as the dengue virus (DENV). While intra-species transcriptome differences remain relatively unstudied when compared to coding sequence polymorphisms, they also affect numerous aspects of mosquito biology. Comparative molecular profiling of mosquito strain transcriptomes can therefore provide valuable insight into the regulation of vector competence. We established a panel of A. aegypti strains with varying levels of susceptibility to DENV, comprising both laboratory-maintained strains and field-derived colonies collected from geographically distinct dengue-endemic regions spanning South America, the Caribbean, and Southeast Asia. A comparative genome-wide gene expression microarray-based analysis revealed higher basal levels of numerous immunity-related gene transcripts in DENV-refractory mosquito strains than in susceptible strains, and RNA interference assays further showed different degrees of immune pathway contribution to refractoriness in different strains. By correlating transcript abundance patterns with DENV susceptibility across our panel, we also identified new candidate modulators of DENV infection in the mosquito, and we provide functional evidence for two potential DENV host factors and one potential restriction factor. Our comparative transcriptome dataset thus not only provides valuable information about immune gene regulation and usage in natural refractoriness of mosquito populations to dengue virus but also allows us to identify new molecular interactions between the virus and its mosquito vector. Genetic variations among Aedes aegypti mosquito populations can greatly influence their ability to transmit human pathogens such as the dengue virus (DENV). Some of these variations between mosquito populations are represented by differences in the expression of specific genes that control susceptibility to a pathogen. We have compared susceptibilities to dengue virus infection and the genome-wide gene expression patterns between laboratory-maintained Aedes aegypti strains as well as field-derived colonies collected from geographically-distinct dengue-endemic regions spanning South America, the Caribbean, and Southeast Asia. These analyses in conjunction with functional gene silencing assays showed that the basal immune activity is a likely determinant of resistance to the dengue virus, along with other novel factors. Our study also identified two potential DENV host factors and one potential restriction factor, thereby elucidating novel aspects of dengue virus – mosquito interactions.
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