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Chen C, Gu Q, Ge Y, Tian J, Zhang Y, Wang T, Wang C, Zhao Y, Xu H, Fan X. Antibiofilm Mechanisms of the Helical G3 Peptide against Staphylococcus epidermidis. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:11806-11816. [PMID: 38770910 DOI: 10.1021/acs.langmuir.4c01474] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2024]
Abstract
Antibacterial peptides (ABPs) have been recognized as promising alternatives to conventional antibiotics due to their broad antibacterial spectrum, high antibacterial activity, and low possibility of inducing bacterial resistance. However, their antibiofilm mechanisms have not yet reached a consensus. In this study, we investigated the antibiofilm activity of a short helical peptide G3 against Staphylococcus epidermidis, one of the most important strains of medical device contamination. Studies show that G3 inhibits S. epidermidis biofilm formation in a variety of ways. In the initial adhesion stage, G3 changes the properties of bacterial surfaces, such as charges, hydrophobicity, and permeability, by rapidly binding to them, thus interfering with their initial adhesion. In the mature stage, G3 prefers to target extracellular polysaccharides, leading to the death of outside bacteria and the disruption of the three-dimensional (3D) architecture of the bacterial biofilm. Such efficient antibiofilm activity of G3 endows it with great potential in the treatment of infections induced by the S. epidermidis biofilm.
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Affiliation(s)
- Cuixia Chen
- State Key Laboratory of Heavy Oil Processing and Centre for Bioengineering and Biotechnology, China University of Petroleum (East China), 66 Changjiang West Road, Qingdao 266580, China
| | - Qilong Gu
- State Key Laboratory of Heavy Oil Processing and Centre for Bioengineering and Biotechnology, China University of Petroleum (East China), 66 Changjiang West Road, Qingdao 266580, China
| | - Yangyang Ge
- State Key Laboratory of Heavy Oil Processing and Centre for Bioengineering and Biotechnology, China University of Petroleum (East China), 66 Changjiang West Road, Qingdao 266580, China
| | - Jingyun Tian
- Marine Science Research Institute of Shandong Province (National Oceanographic Center, Qingdao), 7 Youyun Road, Laoshan District, Qingdao 266104, China
| | - Yusen Zhang
- State Key Laboratory of Heavy Oil Processing and Centre for Bioengineering and Biotechnology, China University of Petroleum (East China), 66 Changjiang West Road, Qingdao 266580, China
| | - Tianling Wang
- State Key Laboratory of Heavy Oil Processing and Centre for Bioengineering and Biotechnology, China University of Petroleum (East China), 66 Changjiang West Road, Qingdao 266580, China
| | - Chen Wang
- State Key Laboratory of Heavy Oil Processing and Centre for Bioengineering and Biotechnology, China University of Petroleum (East China), 66 Changjiang West Road, Qingdao 266580, China
| | - Yurong Zhao
- State Key Laboratory of Heavy Oil Processing and Centre for Bioengineering and Biotechnology, China University of Petroleum (East China), 66 Changjiang West Road, Qingdao 266580, China
| | - Hai Xu
- State Key Laboratory of Heavy Oil Processing and Centre for Bioengineering and Biotechnology, China University of Petroleum (East China), 66 Changjiang West Road, Qingdao 266580, China
| | - Xinglong Fan
- Department of Thoracic Surgery, Qilu Hospital (Qingdao), Cheeloo College of Medicine, Shandong University, Qingdao 266035, China
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2
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Mantegazza G, Dalla Via A, Licata A, Duncan R, Gardana C, Gargari G, Alamprese C, Arioli S, Taverniti V, Karp M, Guglielmetti S. Use of kefir-derived lactic acid bacteria for the preparation of a fermented soy drink with increased estrogenic activity. Food Res Int 2023; 164:112322. [PMID: 36737914 DOI: 10.1016/j.foodres.2022.112322] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Revised: 12/04/2022] [Accepted: 12/05/2022] [Indexed: 12/14/2022]
Abstract
Fermented foods are receiving growing attention for their health promoting properties. In particular, there is a growing demand for plant-based fermented foods as dairy alternatives. Considering that soy is a vegetal food rich in nutrients and a source of the phytoestrogen isoflavones, the aim of this study was to select safe food microorganisms with the ability to ferment a soy drink resulting in a final product with an increased estrogenic activity and improved functional properties. We used milk kefir grains, a dairy source of microorganisms with proven health-promoting properties, as a starting inoculum for a soymilk. After 14 passages of daily inoculum in fresh soy drink, we isolated four lactic acid bacterial strains: Lactotoccus lactis subsp. lactis K03, Leuconostc pseudomesenteroides K05, Leuconostc mesenteroides K09 and Lentilactobacillus kefiri K10. Isolated strains were proven to be safe for human consumption according to the assessment of their antibiotic resistance profile and comparative genomics. Furthermore, functional characterization of the bacterial strains demonstrated their ability to ferment sugars naturally present in soybeans and produce a creamy texture. In addition, we demonstrated, by means of a yeast-based bioluminescence reporter system, that the two strains belonging to the genus Leuconostoc increased the estrogenic activity of the soybean drink. In conclusion, the proposed application of the bacterial strains characterized in this study meets the growing demand of consumers for health-promoting vegetal food alternatives to dairy products.
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Affiliation(s)
- Giacomo Mantegazza
- Department of Food, Environmental and Nutritional Sciences (DeFENS), University of Milan, Italy
| | - Alessandro Dalla Via
- Department of Food, Environmental and Nutritional Sciences (DeFENS), University of Milan, Italy
| | - Armando Licata
- Department of Food, Environmental and Nutritional Sciences (DeFENS), University of Milan, Italy
| | - Robin Duncan
- Department of Food, Environmental and Nutritional Sciences (DeFENS), University of Milan, Italy
| | - Claudio Gardana
- Department of Food, Environmental and Nutritional Sciences (DeFENS), University of Milan, Italy
| | - Giorgio Gargari
- Department of Food, Environmental and Nutritional Sciences (DeFENS), University of Milan, Italy
| | - Cristina Alamprese
- Department of Food, Environmental and Nutritional Sciences (DeFENS), University of Milan, Italy
| | - Stefania Arioli
- Department of Food, Environmental and Nutritional Sciences (DeFENS), University of Milan, Italy
| | - Valentina Taverniti
- Department of Food, Environmental and Nutritional Sciences (DeFENS), University of Milan, Italy
| | - Matti Karp
- Materials Science and Environmental Engineering, Bio and Circular Economy, Tampere University, Finland
| | - Simone Guglielmetti
- Department of Food, Environmental and Nutritional Sciences (DeFENS), University of Milan, Italy.
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3
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Xiong Z, Tian X, Wang G, Song X, Xia Y, Zhang H, Ai L. Development of a high-throughput screening method for exopolysaccharide-producing Streptococcus thermophilus based on Congo red. Food Res Int 2022; 162:112094. [DOI: 10.1016/j.foodres.2022.112094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Revised: 10/23/2022] [Accepted: 10/28/2022] [Indexed: 11/08/2022]
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4
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Wahlig TA, Stanton E, Godfrey JJ, Stasic AJ, Wong ACL, Kaspar CW. A Single Nucleotide Polymorphism in lptG Increases Tolerance to Bile Salts, Acid, and Staining of Calcofluor-Binding Polysaccharides in Salmonella enterica Serovar Typhimurium E40. Front Microbiol 2021; 12:671453. [PMID: 34149657 PMCID: PMC8208086 DOI: 10.3389/fmicb.2021.671453] [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: 02/25/2021] [Accepted: 04/12/2021] [Indexed: 11/13/2022] Open
Abstract
The outer membrane of Salmonella enterica plays an important role in combating stress encountered in the environment and hosts. The transport and insertion of lipopolysaccharides (LPS) into the outer membrane involves lipopolysaccharide transport proteins (LptA-F) and mutations in the genes encoding for these proteins are often lethal or result in the transport of atypical LPS that can alter stress tolerance in bacteria. During studies of heterogeneity in bile salts tolerance, S. enterica serovar Typhimurium E40 was segregated into bile salts tolerant and sensitive cells by screening for growth in TSB with 10% bile salts. An isolate (E40V) with a bile salts MIC >20% was selected for further characterization. Whole-genome sequencing of E40 and E40V using Illumina and PacBio SMRT technologies revealed a non-synonymous single nucleotide polymorphism (SNP) in lptG. Leucine at residue 26 in E40 was substituted with proline in E40V. In addition to growth in the presence of 10% bile salts, E40V was susceptible to novobiocin while E40 was not. Transcriptional analysis of E40 and E40V, in the absence of bile salts, revealed significantly greater (p < 0.05) levels of transcript in three genes in E40V; yjbE (encoding for an extracellular polymeric substance production protein), yciE (encoding for a putative stress response protein), and an uncharacterized gene annotated as an acid shock protein precursor (ASPP). No transcripts of genes were present at a greater level in E40 compared to E40V. Corresponding with the greater level of these transcripts, E40V had greater survival at pH 3.35 and staining of Calcofluor-binding polysaccharide (CBPS). To confirm the SNP in lptG was associated with these phenotypes, strain E40E was engineered from E40 to encode for the variant form of LptG (L26P). E40E exhibited the same differences in gene transcripts and phenotypes as E40V, including susceptibility to novobiocin, confirming the SNP was responsible for these differences.
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Affiliation(s)
- Taylor A Wahlig
- Department of Bacteriology, University of Wisconsin, Madison, WI, United States
| | - Eliot Stanton
- Department of Bacteriology, University of Wisconsin, Madison, WI, United States
| | - Jared J Godfrey
- Department of Bacteriology, University of Wisconsin, Madison, WI, United States
| | - Andrew J Stasic
- U. S. Food and Drug Administration, Center for Biologics Evaluation and Research, Washington, DC, United States
| | - Amy C L Wong
- Department of Bacteriology, University of Wisconsin, Madison, WI, United States
| | - Charles W Kaspar
- Department of Bacteriology, University of Wisconsin, Madison, WI, United States
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Kumar V, Wille M, Lourenço TM, Bossier P. Biofloc-Based Enhanced Survival of Litopenaeus vannamei Upon AHPND-Causing Vibrio parahaemolyticus Challenge Is Partially Mediated by Reduced Expression of Its Virulence Genes. Front Microbiol 2020; 11:1270. [PMID: 32670225 PMCID: PMC7326785 DOI: 10.3389/fmicb.2020.01270] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Accepted: 05/19/2020] [Indexed: 12/23/2022] Open
Abstract
The biofloc system is a relatively new aquaculture technology that offers practical solution to maintain culture water quality by recycling nutrients and improves the health status and resistance of shrimps against microbial infection, yet the mode of action involved remains unclear. This study aimed to unravel the underlying mechanism behind the protective effect of a biofloc system using Litopenaeus vannamei and acute hepatopancreatic necrosis disease (AHPND)-causing Vibrio parahaemolyticus M0904 strain as a host-pathogen model. The results showed that a biofloc system maintained at a C/N ratio of 15, improves the water quality and contributes to the nutrition of cultured animals as bioflocs might serve as an additional protein source. Furthermore, the study demonstrated that the biofloc system enhances the survival of L. vannamei upon challenge with a V. parahaemolyticus AHPND strain. Remarkably, the results highlight that in the biofloc system, AHPND-causing V. parahaemolyticus possibly switch from free-living virulent planktonic phenotype to a non-virulent biofilm phenotype, as demonstrated by a decreased transcription of flagella-related motility genes (flaA, CheR, and fliS), Pir toxin (PirBVP), and AHPND plasmid genes (ORF14) and increased expression of the phenotype switching marker AlkPhoX gene in both in vitro and in vivo conditions. Taken together, results suggest that biofloc steer phenotype switching, contributing to the decreased virulence of V. parahaemolyticus AHPND strain toward shrimp postlarvae. This information reinforces our understanding about AHPND in a biofloc setting and opens the possibility to combat AHPND not only by trying to eliminate the AHPND-causing V. parahaemolyticus from the system but rather to steer the phenotypic switch.
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Affiliation(s)
- Vikash Kumar
- Lab of Aquaculture & Artemia Reference Center, Department of Animal Sciences and Aquatic Ecology, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium.,ICAR-Central Inland Fisheries Research Institute (CIFRI), Barrackpore, India
| | - Mathieu Wille
- Lab of Aquaculture & Artemia Reference Center, Department of Animal Sciences and Aquatic Ecology, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Tânia Margarida Lourenço
- Lab of Aquaculture & Artemia Reference Center, Department of Animal Sciences and Aquatic Ecology, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Peter Bossier
- Lab of Aquaculture & Artemia Reference Center, Department of Animal Sciences and Aquatic Ecology, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
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6
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Becerra-Rivera VA, Arteaga A, Leija A, Hernández G, Dunn MF. Polyamines produced by Sinorhizobium meliloti Rm8530 contribute to symbiotically relevant phenotypes ex planta and to nodulation efficiency on alfalfa. MICROBIOLOGY-SGM 2020; 166:278-287. [PMID: 31935179 DOI: 10.1099/mic.0.000886] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
In nitrogen-fixing rhizobia, emerging evidence shows significant roles for polyamines in growth and abiotic stress resistance. In this work we show that a polyamine-deficient ornithine decarboxylase null mutant (odc2) derived from Sinorhizobium meliloti Rm8530 had significant phenotypic differences from the wild-type, including greatly reduced production of exopolysaccharides (EPS; ostensibly both succinoglycan and galactoglucan), increased sensitivity to oxidative stress and decreased swimming motility. The introduction of the odc2 gene borne on a plasmid into the odc2 mutant restored wild-type phenotypes for EPS production, growth under oxidative stress and swimming. The production of calcofluor-binding EPS (succinoglycan) by the odc2 mutant was also completely or mostly restored in the presence of exogenous spermidine (Spd), norspermidine (NSpd) or spermine (Spm). The odc2 mutant formed about 25 % more biofilm than the wild-type, and its ability to form biofilm was significantly inhibited by exogenous Spd, NSpd or Spm. The odc2 mutant formed a less efficient symbiosis with alfalfa, resulting in plants with significantly less biomass and height, more nodules but less nodule biomass, and 25 % less nitrogen-fixing activity. Exogenously supplied Put was not able to revert these phenotypes and caused a similar increase in plant height and dry weight in uninoculated plants and in those inoculated with the wild-type or odc2 mutant. We discuss ways in which polyamines might affect the phenotypes of the odc2 mutant.
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Affiliation(s)
- Victor A Becerra-Rivera
- Programa de Genómica Funcional de Procariotes, Centro de Ciencias Genómicas-Universidad Nacional Autónoma de México, Cuernavaca, Morelos, C.P. 62210, Mexico
| | - Alejandra Arteaga
- Programa de Genómica Funcional de Procariotes, Centro de Ciencias Genómicas-Universidad Nacional Autónoma de México, Cuernavaca, Morelos, C.P. 62210, Mexico
| | - Alfonso Leija
- Programa de Genómica Funcional de Eucariotes, Centro de Ciencias Genómicas-Universidad Nacional Autónoma de México, Cuernavaca, Morelos, C.P. 62210, Mexico
| | - Georgina Hernández
- Programa de Genómica Funcional de Eucariotes, Centro de Ciencias Genómicas-Universidad Nacional Autónoma de México, Cuernavaca, Morelos, C.P. 62210, Mexico
| | - Michael F Dunn
- Programa de Genómica Funcional de Procariotes, Centro de Ciencias Genómicas-Universidad Nacional Autónoma de México, Cuernavaca, Morelos, C.P. 62210, Mexico
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7
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Kumar V, Roy S, Baruah K, Van Haver D, Impens F, Bossier P. Environmental conditions steer phenotypic switching in acute hepatopancreatic necrosis disease-causing Vibrio parahaemolyticus, affecting PirA VP /PirB VP toxins production. Environ Microbiol 2020; 22:4212-4230. [PMID: 31867836 DOI: 10.1111/1462-2920.14903] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 12/12/2019] [Accepted: 12/18/2019] [Indexed: 12/11/2022]
Abstract
Bacteria in nature are widely exposed to differential fluid shears which are often a trigger for phenotypic switches. The latter mediates transcriptional and translation remodelling of cellular metabolism impacting among others virulence, antimicrobial resistance and stress resistance. In this study, we evaluated the role of fluid shear on phenotypic switch in an acute hepatopancreatic necrosis disease (AHPND)-causing Vibrio parahaemolyticus M0904 strain under both in vitro and in vivo conditions. The results showed that V. parahaemolyticus M0904 grown at lower shaking speed (110 rpm constant agitation, M0904/110), causing low fluid shear, develop cellular aggregates or floccules. These cells increased levan production (as verified by concanavalin binding) and developed differentially stained colonies on Congo red agar plates and resistance to antibiotics. In addition, the phenotypic switch causes a major shift in the protein secretome. At 120 rpm (M0904/120), PirAVP /PirBVP toxins are mainly produced, while at 110 rpm PirAVP /PirBVP toxins production is stopped and an alkaline phosphatase (ALP) PhoX becomes the dominant protein in the protein secretome. These observations are matched with a very strong reduction in virulence of M0904/110 towards two crustacean larvae, namely, Artemia and Macrobrachium. Taken together, our study provides substantial evidence for the existence of two phenotypic forms in AHPND V. parahaemolyticus strain displaying differential phenotypes. Moreover, as aerators and pumping devices are frequently used in shrimp aquaculture facilities, they can inflict fluid shear to the standing microbial agents. Hence, our study could provide a basis to understand the behaviour of AHPND-causing V. parahaemolyticus in aquaculture settings and open the possibility to monitor and control AHPND by steering phenotypes.
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Affiliation(s)
- Vikash Kumar
- Laboratory of Aquaculture & Artemia Reference Center, Faculty of Bioscience Engineering, Department of Animal Sciences and Aquatic Ecology, Ghent University, 9000, Ghent, Belgium.,ICAR - Central Inland Fisheries Research Institute (CIFRI), Barrackpore, 700120, India
| | - Suvra Roy
- Laboratory of Aquaculture & Artemia Reference Center, Faculty of Bioscience Engineering, Department of Animal Sciences and Aquatic Ecology, Ghent University, 9000, Ghent, Belgium.,ICAR - Central Inland Fisheries Research Institute (CIFRI), Barrackpore, 700120, India
| | - Kartik Baruah
- Laboratory of Aquaculture & Artemia Reference Center, Faculty of Bioscience Engineering, Department of Animal Sciences and Aquatic Ecology, Ghent University, 9000, Ghent, Belgium.,Department of Animal Nutrition and Management, Faculty of Veterinary Medicine and Animal Sciences, Swedish University of Agricultural Sciences, Uppsala, 75007, Sweden
| | - Delphi Van Haver
- VIB-UGent Center for Medical Biotechnology, B-9000, Ghent, Belgium.,Department of Biomolecular Medicine, Ghent University, B-9000, Ghent, Belgium.,VIB Proteomics Core, B-9000, Ghent, Belgium
| | - Francis Impens
- VIB-UGent Center for Medical Biotechnology, B-9000, Ghent, Belgium.,Department of Biomolecular Medicine, Ghent University, B-9000, Ghent, Belgium.,VIB Proteomics Core, B-9000, Ghent, Belgium
| | - Peter Bossier
- Laboratory of Aquaculture & Artemia Reference Center, Faculty of Bioscience Engineering, Department of Animal Sciences and Aquatic Ecology, Ghent University, 9000, Ghent, Belgium
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8
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Costa JH, Wassano CI, Angolini CFF, Scherlach K, Hertweck C, Pacheco Fill T. Antifungal potential of secondary metabolites involved in the interaction between citrus pathogens. Sci Rep 2019; 9:18647. [PMID: 31819142 PMCID: PMC6901458 DOI: 10.1038/s41598-019-55204-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Accepted: 11/23/2019] [Indexed: 12/27/2022] Open
Abstract
Numerous postharvest diseases have been reported that cause substantial losses of citrus fruits worldwide. Penicillium digitatum is responsible for up to 90% of production losses, and represent a problem for worldwide economy. In order to control phytopathogens, chemical fungicides have been extensively used. Yet, the use of some artificial fungicides cause concerns about environmental risks and fungal resistance. Therefore, studies focusing on new approaches, such as the use of natural products, are getting attention. Co-culture strategy can be applied to discover new bioactive compounds and to understand microbial ecology. Mass Spectrometry Imaging (MSI) was used to screen for potential antifungal metabolites involved in the interaction between Penicillium digitatum and Penicillium citrinum. MSI revealed a chemical warfare between the fungi: two tetrapeptides, deoxycitrinadin A, citrinadin A, chrysogenamide A and tryptoquialanines are produced in the fungi confrontation zone. Antimicrobial assays confirmed the antifungal activity of the investigated metabolites. Also, tryptoquialanines inhibited sporulation of P. citrinum. The fungal metabolites reported here were never described as antimicrobials until this date, demonstrating that co-cultures involving phytopathogens that compete for the same host is a positive strategy to discover new antifungal agents. However, the use of these natural products on the environment, as a safer strategy, needs further investigation. This paper aimed to contribute to the protection of agriculture, considering health and ecological risks.
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Affiliation(s)
- Jonas Henrique Costa
- Institute of Chemistry, University of Campinas, CP 6154, 13083-970, Campinas, SP, Brazil
| | | | | | - Kirstin Scherlach
- Department of Biomolecular Chemistry, Leibniz Institute for Natural Product Research and Infection Biology - Hans Knöll Institute, Jena, Germany
| | - Christian Hertweck
- Department of Biomolecular Chemistry, Leibniz Institute for Natural Product Research and Infection Biology - Hans Knöll Institute, Jena, Germany.,Chair of Natural Product Chemistry, Friedrich Schiller University Jena, 07743, Jena, Germany
| | - Taícia Pacheco Fill
- Institute of Chemistry, University of Campinas, CP 6154, 13083-970, Campinas, SP, Brazil.
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9
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Ramos Y, Rocha J, Hael AL, van Gestel J, Vlamakis H, Cywes-Bentley C, Cubillos-Ruiz JR, Pier GB, Gilmore MS, Kolter R, Morales DK. PolyGlcNAc-containing exopolymers enable surface penetration by non-motile Enterococcus faecalis. PLoS Pathog 2019; 15:e1007571. [PMID: 30742693 PMCID: PMC6386517 DOI: 10.1371/journal.ppat.1007571] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2018] [Revised: 02/22/2019] [Accepted: 01/08/2019] [Indexed: 11/20/2022] Open
Abstract
Bacterial pathogens have evolved strategies that enable them to invade tissues and spread within the host. Enterococcus faecalis is a leading cause of local and disseminated multidrug-resistant hospital infections, but the molecular mechanisms used by this non-motile bacterium to penetrate surfaces and translocate through tissues remain largely unexplored. Here we present experimental evidence indicating that E. faecalis generates exopolysaccharides containing β-1,6-linked poly-N-acetylglucosamine (polyGlcNAc) as a mechanism to successfully penetrate semisolid surfaces and translocate through human epithelial cell monolayers. Genetic screening and molecular analyses of mutant strains identified glnA, rpiA and epaX as genes critically required for optimal E. faecalis penetration and translocation. Mechanistically, GlnA and RpiA cooperated to generate uridine diphosphate N-acetylglucosamine (UDP-GlcNAc) that was utilized by EpaX to synthesize polyGlcNAc-containing polymers. Notably, exogenous supplementation with polymeric N-acetylglucosamine (PNAG) restored surface penetration by E. faecalis mutants devoid of EpaX. Our study uncovers an unexpected mechanism whereby the RpiA-GlnA-EpaX metabolic axis enables production of polyGlcNAc-containing polysaccharides that endow E. faecalis with the ability to penetrate surfaces. Hence, targeting carbohydrate metabolism or inhibiting biosynthesis of polyGlcNAc-containing exopolymers may represent a new strategy to more effectively confront enterococcal infections in the clinic. Enterococcus faecalis is a microbial inhabitant of the human gastrointestinal tract that can cause lethal infections. Typically classified as a non-motile bacterium, E. faecalis can readily migrate and translocate across epithelial barriers to invade distant organs. Nevertheless, the molecular pathways driving enterococcal invasive attributes remain poorly understood. In this study, we uncover that E. faecalis produces a polyGlcNAc-containing extracellular glycopolymer to efficiently migrate into semisolid surfaces and translocate through human epithelial cell monolayers. Our work provides evidence that non-motile bacterial pathogens can exploit endogenous carbohydrate metabolic pathways to penetrate surfaces. Thus, targeting glycopolymer biosynthetic programs might be useful to control infections by Gram-positive cocci in the clinic.
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Affiliation(s)
- Yusibeska Ramos
- Department of Obstetrics and Gynecology, Weill Cornell Medicine, New York, NY, United States of America
| | - Jorge Rocha
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA, United States of America
| | - Ana L. Hael
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA, United States of America
| | - Jordi van Gestel
- Department of Evolutionary Biology and Environmental Studies, University of Zürich, Zürich, Switzerland
- Swiss Institute of Bioinformatics, Lausanne, Switzerland
- Department of Environmental Microbiology, Swiss Federal Institute of Aquatic Science and Technology (Eawag), Dübendorf, Switzerland
- Department of Environmental Systems Science, ETH Zürich, Zürich, Switzerland
| | - Hera Vlamakis
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA, United States of America
| | - Colette Cywes-Bentley
- Division of Infectious Diseases, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, United States of America
| | - Juan R. Cubillos-Ruiz
- Department of Obstetrics and Gynecology, Weill Cornell Medicine, New York, NY, United States of America
| | - Gerald B. Pier
- Division of Infectious Diseases, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, United States of America
| | - Michael S. Gilmore
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA, United States of America
- Department of Ophthalmology, Harvard Medical School, Boston, MA, United States of America
| | - Roberto Kolter
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA, United States of America
| | - Diana K. Morales
- Department of Obstetrics and Gynecology, Weill Cornell Medicine, New York, NY, United States of America
- * E-mail:
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10
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Jofré E, Liaudat JP, Medeot D, Becker A. Monitoring succinoglycan production in single Sinorhizobium meliloti cells by Calcofluor white M2R staining and time-lapse microscopy. Carbohydr Polym 2018; 181:918-922. [DOI: 10.1016/j.carbpol.2017.11.059] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Revised: 11/14/2017] [Accepted: 11/16/2017] [Indexed: 11/28/2022]
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11
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Hawkins JP, Ordonez PA, Oresnik IJ. Characterization of Mutations That Affect the Nonoxidative Pentose Phosphate Pathway in Sinorhizobium meliloti. J Bacteriol 2018; 200:e00436-17. [PMID: 29084855 PMCID: PMC5738737 DOI: 10.1128/jb.00436-17] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Accepted: 10/21/2017] [Indexed: 12/12/2022] Open
Abstract
Sinorhizobium meliloti is a Gram-negative alphaproteobacterium that can enter into a symbiotic relationship with Medicago sativa and Medicago truncatula Previous work determined that a mutation in the tkt2 gene, which encodes a putative transketolase, could prevent medium acidification associated with a mutant strain unable to metabolize galactose. Since the pentose phosphate pathway in S. meliloti is not well studied, strains carrying mutations in either tkt2 and tal, which encodes a putative transaldolase, were characterized. Carbon metabolism phenotypes revealed that both mutants were impaired in growth on erythritol and ribose. This phenotype was more pronounced for the tkt2 mutant strain, which also displayed auxotrophy for aromatic amino acids. Changes in pentose phosphate pathway metabolite concentrations were also consistent with a mutation in either tkt2 or tal The concentrations of metabolites in central carbon metabolism were also found to shift dramatically in strains carrying a tkt2 mutation. While the concentrations of proteins involved in central carbon metabolism did not change significantly under any conditions, the levels of those associated with iron acquisition increased in the wild-type strain with erythritol induction. These proteins were not detected in either mutant, resulting in less observable rhizobactin production in the tkt2 mutant. While both mutants were impaired in succinoglycan synthesis, only the tkt2 mutant strain was unable to establish symbiosis with alfalfa. These results suggest that tkt2 and tal play central roles in regulating the carbon flow necessary for carbon metabolism and the establishment of symbiosis.IMPORTANCESinorhizobium meliloti is a model organism for the study of plant-microbe interactions and metabolism, especially because it effects nitrogen fixation. The ability to derive the energy necessary for nitrogen fixation is dependent on an organism's ability to metabolize carbon efficiently. The pentose phosphate pathway is central in the interconversion of hexoses and pentoses. This study characterizes the key enzymes of the nonoxidative branch of the pentose phosphate pathway by using defined genetic mutations and shows the effects the mutations have on the metabolite profile and on physiological processes such as the biosynthesis of exopolysaccharide, as well as the ability to regulate iron acquisition.
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Affiliation(s)
- Justin P Hawkins
- Department of Microbiology, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Patricia A Ordonez
- Department of Microbiology, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Ivan J Oresnik
- Department of Microbiology, University of Manitoba, Winnipeg, Manitoba, Canada
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