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Stege PB, Beekman JM, Hendrickx APA, van Eijk L, Rogers MRC, Suen SWF, Vonk AM, Willems RJL, Paganelli FL. Colonization of vancomycin-resistant Enterococcus faecium in human-derived colonic epithelium: unraveling the transcriptional dynamics of host-enterococcal interactions. FEMS MICROBES 2024; 5:xtae014. [PMID: 38813098 PMCID: PMC11134301 DOI: 10.1093/femsmc/xtae014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Revised: 03/27/2024] [Accepted: 05/06/2024] [Indexed: 05/31/2024] Open
Abstract
Enterococcus faecium is an opportunistic pathogen able to colonize the intestines of hospitalized patients. This initial colonization is an important step in the downstream pathogenesis, which includes outgrowth of the intestinal microbiota and potential infection of the host. The impact of intestinal overgrowth on host-enterococcal interactions is not well understood. We therefore applied a RNAseq approach in order to unravel the transcriptional dynamics of E. faecium upon co-culturing with human derived colonic epithelium. Co-cultures of colonic epithelium with a hospital-associated vancomycin resistant (vanA-type) E. faecium (VRE) showed that VRE resided on top of the colonic epithelium when analyzed by microscopy. RNAseq revealed that exposure to the colonic epithelium resulted in upregulation of 238 VRE genes compared to the control condition, including genes implicated in pili expression, conjugation (plasmid_2), genes related to sugar uptake, and biofilm formation (chromosome). In total, 260 were downregulated, including the vanA operon located on plasmid_3. Pathway analysis revealed an overall switch in metabolism to amino acid scavenging and reduction. In summary, our study demonstrates that co-culturing of VRE with human colonic epithelium promotes an elaborate gene response in VRE, enhancing our insight in host-E. faecium interactions, which might facilitate the design of novel anti-infectivity strategies.
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Affiliation(s)
- Paul B Stege
- Department of Medical Microbiology, UMC Utrecht, Utrecht, 3584CX, The Netherlands
| | - Jeffrey M Beekman
- Department of Pediatric Pulmonology, Wilhelmina Children's Hospital, University Medical Center Utrecht, Utrecht University, Utrecht, 3584CX, The Netherlands
- Regenerative Medicine Utrecht, University Medical Center Utrecht, Utrecht University, Utrecht, 3584CX, The Netherlands
| | - Antoni P A Hendrickx
- Centre for Infectious Disease Control, National Institute for Public Health and the Environment (RIVM), 3721MA, The Netherlands
| | - Laura van Eijk
- Department of Medical Microbiology, UMC Utrecht, Utrecht, 3584CX, The Netherlands
| | - Malbert R C Rogers
- Department of Medical Microbiology, UMC Utrecht, Utrecht, 3584CX, The Netherlands
| | - Sylvia W F Suen
- Department of Pediatric Pulmonology, Wilhelmina Children's Hospital, University Medical Center Utrecht, Utrecht University, Utrecht, 3584CX, The Netherlands
- Regenerative Medicine Utrecht, University Medical Center Utrecht, Utrecht University, Utrecht, 3584CX, The Netherlands
| | - Annelotte M Vonk
- Department of Pediatric Pulmonology, Wilhelmina Children's Hospital, University Medical Center Utrecht, Utrecht University, Utrecht, 3584CX, The Netherlands
- Regenerative Medicine Utrecht, University Medical Center Utrecht, Utrecht University, Utrecht, 3584CX, The Netherlands
| | - Rob J L Willems
- Department of Medical Microbiology, UMC Utrecht, Utrecht, 3584CX, The Netherlands
| | - Fernanda L Paganelli
- Department of Medical Microbiology, UMC Utrecht, Utrecht, 3584CX, The Netherlands
- Winclove Probiotics, Amsterdam, 1033JS, The Netherlands
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Gao S, Wang Y, Yuan S, Zuo J, Jin W, Shen Y, Grenier D, Yi L, Wang Y. Cooperation of quorum sensing and central carbon metabolism in the pathogenesis of Gram-positive bacteria. Microbiol Res 2024; 282:127655. [PMID: 38402726 DOI: 10.1016/j.micres.2024.127655] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Revised: 01/25/2024] [Accepted: 02/17/2024] [Indexed: 02/27/2024]
Abstract
Quorum sensing (QS), an integral component of bacterial communication, is essential in coordinating the collective response of diverse bacterial pathogens. Central carbon metabolism (CCM), serving as the primary metabolic hub for substances such as sugars, lipids, and amino acids, plays a crucial role in the life cycle of bacteria. Pathogenic bacteria often utilize CCM to regulate population metabolism and enhance the synthesis of specific cellular structures, thereby facilitating in adaptation to the host microecological environment and expediting infection. Research has demonstrated that QS can both directly or indirectly affect the CCM of numerous pathogenic bacteria, thus altering their virulence and pathogenicity. This article reviews the interplay between QS and CCM in Gram-positive pathogenic bacteria, details the molecular mechanisms by which QS modulates CCM, and lays the groundwork for investigating bacterial pathogenicity and developing innovative infection treatment drugs.
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Affiliation(s)
- Shuji Gao
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang 471000, China; Henan Provincial Engineering Research Center for Detection and Prevention and Control of Emerging Infectious Diseases in Livestock and Poultry, Luoyang 471003, China
| | - Yuxin Wang
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang 471000, China; Henan Provincial Engineering Research Center for Detection and Prevention and Control of Emerging Infectious Diseases in Livestock and Poultry, Luoyang 471003, China
| | - Shuo Yuan
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang 471000, China; Henan Provincial Engineering Research Center for Detection and Prevention and Control of Emerging Infectious Diseases in Livestock and Poultry, Luoyang 471003, China
| | - Jing Zuo
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang 471000, China; Henan Provincial Engineering Research Center for Detection and Prevention and Control of Emerging Infectious Diseases in Livestock and Poultry, Luoyang 471003, China
| | - Wenjie Jin
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang 471000, China; Henan Provincial Engineering Research Center for Detection and Prevention and Control of Emerging Infectious Diseases in Livestock and Poultry, Luoyang 471003, China
| | - Yamin Shen
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang 471000, China; Henan Provincial Engineering Research Center for Detection and Prevention and Control of Emerging Infectious Diseases in Livestock and Poultry, Luoyang 471003, China
| | - Daniel Grenier
- Groupe de Recherche en Écologie Buccale, Faculté de Médecine Dentaire, Université Laval, Quebec City, Quebec, Canada
| | - Li Yi
- Henan Provincial Engineering Research Center for Detection and Prevention and Control of Emerging Infectious Diseases in Livestock and Poultry, Luoyang 471003, China; College of Life Science, Luoyang Normal University, Luoyang 471934, China.
| | - Yang Wang
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang 471000, China; Henan Provincial Engineering Research Center for Detection and Prevention and Control of Emerging Infectious Diseases in Livestock and Poultry, Luoyang 471003, China.
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Takemiya K, Wang S, Liu Y, Murthy N, Goodman MM, Taylor WR. Isothermal titration calorimetry analysis of the binding between the maltodextrin binding protein malE of Staphylococcus aureus with maltodextrins of various lengths. Biochem Biophys Res Commun 2024; 695:149467. [PMID: 38211531 PMCID: PMC10842747 DOI: 10.1016/j.bbrc.2023.149467] [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: 09/05/2023] [Revised: 12/12/2023] [Accepted: 12/30/2023] [Indexed: 01/13/2024]
Abstract
Staphylococcus aureus (S. aureus), a Gram-positive bacterium, causes a wide range of infections, and diagnosis at an early stage is challenging. Targeting the maltodextrin transporter has emerged as a promising strategy for imaging bacteria and has been able to image a wide range of bacteria including S. aureus. However, little is known about the maltodextrin transporter in S. aureus, and this prevents new S. aureus specific ligands for the maltodextrin transporter from being developed. In Gram-positive bacteria, including S. aureus, the first step of maltodextrin transport is the binding of the maltodextrin-binding protein malE to maltodextrins. Thus, understanding the binding affinity and characteristics of malE from S. aureus is important to developing efficient maltodextrin-based imaging probes. We evaluated the affinity of malE of S. aureus to maltodextrins of various lengths. MalE of S. aureus (SAmalE) was expressed in E. coli BL21(DE3) and purified by Ni-NTA resin. The affinities of SAmalE to maltodextrins were evaluated with isothermal titration calorimetry. SAmalE has low affinity to maltose but binds to maltotriose and longer maltodextrins up to maltoheptaose with affinities up to Ka = 9.02 ± 0.49 × 105 M-1. SAmalE binding to maltotriose-maltoheptaose was exothermic and fit a single-binding site model. The van't Hoff enthalpy in the binding reaction of SAmalE with maltotriose was 9.9 ± 1.3 kcal/mol, and the highest affinity of SAmalE was observed with maltotetraose with Ka = 9.02 ± 0.49 × 105 M-1. In the plot of ΔH-T*ΔS, the of Enthalpy-Entropy Compensation effect was observed in binding reaction of SAmalE to maltodextrins. Acarbose and maltotetraiol bind with SAmalE indicating that SAmalE is tolerant of modifications on both the reducing and non-reducing ends of maltodextrins. Our results show that unlike ECmalE and similar to the maltodextrin binding protein of Streptococci, SAmalE primarily binds to maltodextrins via hydrogen bonds. This is distinct from the maltodextrin binding protein of Streptococci, SAmalE that binds to maltotetraiol with high affinity. Understanding the binding characteristics and tolerance to maltodextrins modifications by maltodextrin binding proteins will hopefully provide the basis for developing bacterial species-specific maltodextrin-based imaging probes.
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Affiliation(s)
- Kiyoko Takemiya
- Division of Cardiology, Department of Medicine, Emory University School of Medicine, 1750 Haygood Dr. NE, Atlanta, GA, 30322, USA.
| | - Shelly Wang
- Division of Cardiology, Department of Medicine, Emory University School of Medicine, 1750 Haygood Dr. NE, Atlanta, GA, 30322, USA
| | - Yu Liu
- Division of Cardiology, Department of Medicine, Emory University School of Medicine, 1750 Haygood Dr. NE, Atlanta, GA, 30322, USA
| | - Niren Murthy
- Department of Bioengineering, Stanley Hall 306 University of California at Berkeley, Berkeley, CA, 94720, USA
| | - Mark M Goodman
- Department of Radiology and Imaging Sciences, School of Medicine, Emory University, 1364 Clifton Road NE, Atlanta, GA, 30322, USA; Center for Systems Imaging, Emory University, 1364 Clifton Rd NE, Atlanta, 30322, Georgia
| | - W Robert Taylor
- Division of Cardiology, Department of Medicine, Emory University School of Medicine, 1750 Haygood Dr. NE, Atlanta, GA, 30322, USA; Joseph Maxwell Cleland Atlanta VA Medical Center, 1670 Clairmont Road, Decatur, GA, 30033, USA; Wallace H. Coulter Department of Biomedical Engineering School of Medicine, Emory University, 1750 Haygood Dr. NE, Atlanta, GA, 30322, USA
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Bláhová M, Štefuca V, Hronská H, Rosenberg M. Maltooligosaccharides: Properties, Production and Applications. Molecules 2023; 28:molecules28073281. [PMID: 37050044 PMCID: PMC10097025 DOI: 10.3390/molecules28073281] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 03/29/2023] [Accepted: 04/04/2023] [Indexed: 04/14/2023] Open
Abstract
Maltooligosaccharides (MOS) are homooligosaccharides that consist of 3-10 glucose molecules linked by α-1,4 glycosidic bonds. As they have physiological functions, they are commonly used as ingredients in nutritional products and functional foods. Many researchers have investigated the potential applications of MOS and their derivatives in the pharmaceutical industry. In this review, we summarized the properties and methods of fabricating MOS and their derivatives, including sulfated and non-sulfated alkylMOS. For preparing MOS, different enzymatic strategies have been proposed by various researchers, using α-amylases, maltooligosaccharide-forming amylases, or glycosyltransferases as effective biocatalysts. Many researchers have focused on using immobilized biocatalysts and downstream processes for MOS production. This review also provides an overview of the current challenges and future trends of MOS production.
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Affiliation(s)
- Mária Bláhová
- Faculty of Chemical and Food Technology, Institute of Biotechnology, Slovak University of Technology, Radlinského 9, 812 37 Bratislava, Slovakia
| | - Vladimír Štefuca
- Faculty of Chemical and Food Technology, Institute of Biotechnology, Slovak University of Technology, Radlinského 9, 812 37 Bratislava, Slovakia
| | - Helena Hronská
- Faculty of Chemical and Food Technology, Institute of Biotechnology, Slovak University of Technology, Radlinského 9, 812 37 Bratislava, Slovakia
| | - Michal Rosenberg
- Faculty of Chemical and Food Technology, Institute of Biotechnology, Slovak University of Technology, Radlinského 9, 812 37 Bratislava, Slovakia
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Wang L, Bu T, Bai X, He S, Zhang J, Jin L, Liu B, Dong Y, Ha NC, Quan C, Nam KH, Xu Y. Crystal structure of the domain-swapped dimeric maltodextrin-binding protein MalE from Salmonella enterica. ACTA CRYSTALLOGRAPHICA SECTION D STRUCTURAL BIOLOGY 2022; 78:613-622. [DOI: 10.1107/s2059798322003114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Accepted: 03/22/2022] [Indexed: 11/10/2022]
Abstract
MalE is a maltose/maltodextrin-binding protein (MBP) that plays a critical role in most bacterial maltose/maltodextrin-transport systems. Previously reported wild-type MBPs are monomers comprising an N-terminal domain (NTD) and a C-terminal domain (CTD), and maltose-like molecules are recognized between the NTD and CTD and transported to the cell system. Because MBP does not undergo artificial dimerization, it is widely used as a tag for protein expression and purification. Here, the crystal structure of a domain-swapped dimeric MalE from Salmonella enterica (named SeMalE) in complex with maltopentaose is reported for the first time, and its structure is distinct from typical monomeric MalE family members. In the domain-swapped dimer, SeMalE comprises two subdomains: the NTD and CTD. The NTD and CTD of one molecule of SeMalE interact with the CTD and NTD of the partner molecule, respectively. The domain-swapped dimeric conformation was stabilized by interactions between the NTDs, CTDs and linkers from two SeMalE molecules. Additionally, a maltopentaose molecule was found to be located at the interface between the NTD and CTD of different SeMalE molecules. These results provide new insights that will improve the understanding of maltodextrin-binding MalE proteins.
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Sun H, Gao H, Zuo X, Kai G. Transcriptome response of cold-pretreated Pantoea agglomerans KSC03 to exogenous green leaf volatile E-2-hexenal. CHEMOECOLOGY 2022. [DOI: 10.1007/s00049-021-00367-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Ali IAA, Lévesque CM, Neelakantan P. Fsr quorum sensing system modulates the temporal development of Enterococcus faecalis biofilm matrix. Mol Oral Microbiol 2021; 37:22-30. [PMID: 34862746 DOI: 10.1111/omi.12357] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 11/13/2021] [Accepted: 11/30/2021] [Indexed: 11/27/2022]
Abstract
Quorum sensing (QS) is a cell-to-cell communication process that regulates major pathogenic attributes in bacteria including biofilm formation, secretion of virulence factors, and antimicrobial resistance. The two-component Fsr-QS system of the nosocomial pathogen Enterococcus faecalis controls the production of extracellular gelatinase that contributes to biofilm development by enhancing the release of nucleic acids into the biofilm matrix. However, the contribution of this system to the deposition of other biofilm matrix components such as polysaccharides and proteins remains unknown. Using wild type and mutant strains, we discovered that biofilm formation was attenuated by inactivation of the Fsr system or its downstream gelatinase production. Inactivation of the Fsr system caused a modest, yet significant reduction in biofilm metabolic activity without affecting cell counts. Inactivation of the QS-signal sensor FsrC and response regulator FsrA resulted in decreased extracellular polysaccharides and proteins in biofilms in a temporal manner. Irrespective of biofilm age, eDNA levels were reduced in the gelatinase mutant strain. Our results collectively suggest that the Fsr system contributes to the temporal deposition of polysaccharides and proteins into the extracellular polymeric matrix (EPS) of E. faecalis biofilm, without affecting bacterial viability. This understanding of the role of the Fsr-QS system in biofilm development may reveal a novel target to develop effective antibiofilm agents to tackle E. faecalis-mediated infections such as in dental root canals, heart valves, and surgical sites.
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Affiliation(s)
- Islam A A Ali
- Faculty of Dentistry, The University of Hong Kong, Sai Ying Pun, Hong Kong SAR, China
| | | | - Prasanna Neelakantan
- Faculty of Dentistry, The University of Hong Kong, Sai Ying Pun, Hong Kong SAR, China
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Occurrence and Transmission of bla NDM-Carrying Enterobacteriaceae from Geese and the Surrounding Environment on a Commercial Goose Farm. Appl Environ Microbiol 2021; 87:AEM.00087-21. [PMID: 33674440 DOI: 10.1128/aem.00087-21] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Accepted: 03/01/2021] [Indexed: 12/28/2022] Open
Abstract
We investigated the prevalence and transmission of NDM-producing Enterobacteriaceae in fecal samples of geese and environmental samples from a goose farm in southern China. The samples were cultivated on MacConkey agar plates supplemented with meropenem. Individual colonies were examined for bla NDM, and bla NDM-positive bacteria were characterized based on whole-genome sequencing (WGS) data from the Illumina and Oxford Nanopore Technologies (ONT) platforms. Of 117 samples analyzed, the carriage rates for New Delhi metallo-β-lactamase (NDM)-positive Enterobacteriaceae were 47.1, 18, and 50% in geese, inanimate environments (sewage, soil, fodder, and dust), and mouse samples, respectively. Two variants (bla NDM-1 and bla NDM-5, in 4 and 40 isolates, respectively) were found among 44 bla NDM-positive Enterobacteriaceae; these variants belonged to eight species, and Escherichia coli was the most prevalent (50%). WGS analysis revealed that bla NDM coexisted with diverse antibiotic resistance genes (ARGs). Population structure analysis showed that most E. coli and Enterobacter sp. isolates were highly heterogeneous, while most Citrobacter sp. and P. stuartii isolates possessed extremely high genetic similarities. In addition, bla NDM-5-positive ST4358/ST48 E. coli isolates were found to be clonally spread between geese and the environment and were highly genetically similar to those reported from ducks, farm environments, and humans in China. Plasmid analysis indicated that IncX3 pHNYX644-1-like (n = 40) and untypeable pM2-1-like plasmids (n = 4) mediated bla NDM spread. pM2-1-like plasmids possessed diverse ARGs, including bla NDM-1, the arsenical and mercury resistance operons, and the maltose operon. Our findings revealed that the goose farm is a reservoir for NDM-positive Enterobacteriaceae The bla NDM contamination of wild mice and the novel pM2-1-like plasmid described here likely adds to the risk for dissemination of bla NDM and associated resistance genes.IMPORTANCE Carbapenem-resistant bacteria, in particular NDM-producing Enterobacteriaceae, have become a great threat to global public. These bacteria have been found not only in hospital and community environments but also among food animal production chains, which are recognized as reservoirs for NDM-producing Enterobacteriaceae However, the dissemination of NDM-producing bacteria in waterfowl farms has been less well explored. Our study demonstrates that the horizontal spread of bla NDM-carrying plasmids and the partial clonal spread of bla NDM-positive Enterobacteriaceae contribute to the widespread contamination of bla NDM in the goose farm ecosystem, including mice. Furthermore, we found a novel and transferable bla NDM-1-carrying multidrug resistance (MDR) plasmid that possessed multiple environmental adaptation-related genes. The outcomes of this study contribute to a better understanding of the prevalence and transmission of bla NDM-carrying Enterobacteriaceae among diverse niches in the farm ecosystem.
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Nguyen MT, Matsuo M, Niemann S, Herrmann M, Götz F. Lipoproteins in Gram-Positive Bacteria: Abundance, Function, Fitness. Front Microbiol 2020; 11:582582. [PMID: 33042100 PMCID: PMC7530257 DOI: 10.3389/fmicb.2020.582582] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2020] [Accepted: 08/27/2020] [Indexed: 12/14/2022] Open
Abstract
When one thinks of the Gram+ cell wall, the peptidoglycan (PG) scaffold in particular comes to mind. However, the cell wall also consists of many other components, for example those that are covalently linked to the PG: the wall teichoic acid and the cell wall proteins tethered by the sortase. In addition, there are completely different molecules that are anchored in the cytoplasmic membrane and span the cell wall. These are lipoteichoic acids and bacterial lipoproteins (Lpp). The latter are in the focus of this review. Lpp are present in almost all bacteria. They fulfill a wealth of different tasks. They represent the window to the outside world by recognizing nutrients and incorporating them into the bacterial cell via special transport systems. Furthermore, they perform very diverse and special tasks such as acting as chaperonin, as cyclomodulin, contributing to invasion of host cells or uptake of plasmids via conjugation. All these functions are taken over by the protein part. Nevertheless, the lipid part of the Lpp plays an as important role as the protein part. It is the released lipoproteins and derived lipopeptides that massively modulate our immune system and ultimately play an important role in immune tolerance or non-tolerance. All these varied activities of the Lpp are considered in this review article.
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Affiliation(s)
- Minh-Thu Nguyen
- Section of Medical and Geographical Infectiology, Institute of Medical Microbiology, University Hospital of Münster, Münster, Germany
| | - Miki Matsuo
- Interfaculty Institute of Microbiology and Infection Medicine Tübingen (IMIT), Microbial Genetics, University of Tübingen, Tübingen, Germany
| | - Silke Niemann
- Section of Medical and Geographical Infectiology, Institute of Medical Microbiology, University Hospital of Münster, Münster, Germany
| | - Mathias Herrmann
- Section of Medical and Geographical Infectiology, Institute of Medical Microbiology, University Hospital of Münster, Münster, Germany
| | - Friedrich Götz
- Interfaculty Institute of Microbiology and Infection Medicine Tübingen (IMIT), Microbial Genetics, University of Tübingen, Tübingen, Germany
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Enterococcus faecalis Maltodextrin Gene Regulation by Combined Action of Maltose Gene Regulator MalR and Pleiotropic Regulator CcpA. Appl Environ Microbiol 2020; 86:AEM.01147-20. [PMID: 32680872 DOI: 10.1128/aem.01147-20] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Accepted: 07/08/2020] [Indexed: 01/13/2023] Open
Abstract
Enterococci are Gram-positive bacteria present in the healthy human microbiota, but they are also a leading cause of nosocomial infections. Maltodextrin utilization by Enterococcus faecalis has been identified as an important factor for colonization of mammalians hosts. Here, we show that the LacI/GalR transcriptional regulator MalR, the maltose gene regulator, is also the main regulator of the operons encoding an ABC transporter (mdxEFG) and three metabolic enzymes (mmdH-gmdH-mmgT) required for the uptake and catabolism of maltotetraose and longer maltodextrins. The utilization of maltose and maltodextrins is consequently coordinated and induced by the disaccharide maltose, which binds to MalR. Carbon catabolite repression of the mdxEFG and mmdH-gmdH-mmgT operons is mediated by both P-Ser-HPr/MalR and P-Ser-HPr/CcpA. The latter complex exerts only moderate catabolite repression, which became visible when comparing maltodextrin operon expression levels of a malR - mutant (with a mutant allele for the malR gene) and a malR - ΔccpA double mutant grown in the presence of maltose, which is transported via a phosphotransferase system and, thus, favors the formation of P-Ser-HPr. Moreover, maltodextrin transport via MdxEFG slows rapidly when glucose is added, suggesting an additional regulation via inducer exclusion. This complex regulation of metabolic operons likely allows E. faecalis to fine-tune gene expression in response to changing environmental conditions.IMPORTANCE Enterococcus faecalis represents a leading cause of hospital-acquired infections worldwide. Several studies highlighted the importance of carbohydrate metabolism in the infection process of this bacterium. The genes required for maltodextrin metabolism are particularly induced during mouse infection and, therefore, should play an important role for pathogenesis. Since no data were hitherto available concerning the regulation of expression of the maltodextrin operons, we have conducted experiments to study the underlying mechanisms.
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Sanchez-Herrero JF, Bernabeu M, Prieto A, Hüttener M, Juárez A. Gene Duplications in the Genomes of Staphylococci and Enterococci. Front Mol Biosci 2020; 7:160. [PMID: 32850954 PMCID: PMC7396535 DOI: 10.3389/fmolb.2020.00160] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Accepted: 06/24/2020] [Indexed: 12/28/2022] Open
Abstract
Gene duplications are a feature of bacterial genomes. In the present work we analyze the extent of gene duplications in the genomes of three microorganisms that belong to the Firmicutes phylum and that are etiologic agents of several nosocomial infections: Staphylococcus aureus, Enterococcus faecium, and Enterococcus faecalis. In all three groups, there is an irregular distribution of duplications in the genomes of the strains analyzed. Whereas in some of the strains duplications are scarce, hundreds of duplications are present in others. In all three species, mobile DNA accounts for a large percentage of the duplicated genes: phage DNA in S. aureus, and plasmid DNA in the enterococci. Duplicates also include core genes. In all three species, a reduced group of genes is duplicated in all strains analyzed. Duplication of the deoC and rpmG genes is a hallmark of S. aureus genomes. Duplication of the gene encoding the PTS IIB subunit is detected in all enterococci genomes. In E. faecalis it is remarkable that the genomes of some strains encode duplicates of the prgB and prgU genes. They belong to the prgABCU cluster, which responds to the presence of the peptide pheromone cCF10 by expressing the surface adhesins PrgA, PrgB, and PrgC.
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Affiliation(s)
- José Francisco Sanchez-Herrero
- Department of Genetics, Microbiology and Statistics, University of Barcelona, Barcelona, Spain.,Biodiversity Research Institute (IRBio), University of Barcelona, Barcelona, Spain.,High Content Genomics and Bioinformatics Unit, Germans Trias i Pujol Research Institute (IGTP), Campus Can Ruti, Badalona, Spain
| | - Manuel Bernabeu
- Department of Genetics, Microbiology and Statistics, University of Barcelona, Barcelona, Spain
| | - Alejandro Prieto
- Department of Genetics, Microbiology and Statistics, University of Barcelona, Barcelona, Spain
| | - Mário Hüttener
- Department of Genetics, Microbiology and Statistics, University of Barcelona, Barcelona, Spain
| | - Antonio Juárez
- Department of Genetics, Microbiology and Statistics, University of Barcelona, Barcelona, Spain.,Institute for Bioengineering of Catalonia, The Barcelona Institute of Science and Technology, Barcelona, Spain
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Fodor A, Abate BA, Deák P, Fodor L, Gyenge E, Klein MG, Koncz Z, Muvevi J, Ötvös L, Székely G, Vozik D, Makrai L. Multidrug Resistance (MDR) and Collateral Sensitivity in Bacteria, with Special Attention to Genetic and Evolutionary Aspects and to the Perspectives of Antimicrobial Peptides-A Review. Pathogens 2020; 9:pathogens9070522. [PMID: 32610480 PMCID: PMC7399985 DOI: 10.3390/pathogens9070522] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 06/23/2020] [Accepted: 06/23/2020] [Indexed: 12/18/2022] Open
Abstract
Antibiotic poly-resistance (multidrug-, extreme-, and pan-drug resistance) is controlled by adaptive evolution. Darwinian and Lamarckian interpretations of resistance evolution are discussed. Arguments for, and against, pessimistic forecasts on a fatal “post-antibiotic era” are evaluated. In commensal niches, the appearance of a new antibiotic resistance often reduces fitness, but compensatory mutations may counteract this tendency. The appearance of new antibiotic resistance is frequently accompanied by a collateral sensitivity to other resistances. Organisms with an expanding open pan-genome, such as Acinetobacter baumannii, Pseudomonas aeruginosa, and Klebsiella pneumoniae, can withstand an increased number of resistances by exploiting their evolutionary plasticity and disseminating clonally or poly-clonally. Multidrug-resistant pathogen clones can become predominant under antibiotic stress conditions but, under the influence of negative frequency-dependent selection, are prevented from rising to dominance in a population in a commensal niche. Antimicrobial peptides have a great potential to combat multidrug resistance, since antibiotic-resistant bacteria have shown a high frequency of collateral sensitivity to antimicrobial peptides. In addition, the mobility patterns of antibiotic resistance, and antimicrobial peptide resistance, genes are completely different. The integron trade in commensal niches is fortunately limited by the species-specificity of resistance genes. Hence, we theorize that the suggested post-antibiotic era has not yet come, and indeed might never come.
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Affiliation(s)
- András Fodor
- Department of Genetics, University of Szeged, H-6726 Szeged, Hungary;
- Correspondence: or (A.F.); (L.M.); Tel.: +36-(30)-490-9294 (A.F.); +36-(30)-271-2513 (L.M.)
| | - Birhan Addisie Abate
- Ethiopian Biotechnology Institute, Agricultural Biotechnology Directorate, Addis Ababa 5954, Ethiopia;
| | - Péter Deák
- Department of Genetics, University of Szeged, H-6726 Szeged, Hungary;
- Institute of Biochemistry, Biological Research Centre, H-6726 Szeged, Hungary
| | - László Fodor
- Department of Microbiology and Infectious Diseases, University of Veterinary Medicine, P.O. Box 22, H-1581 Budapest, Hungary;
| | - Ervin Gyenge
- Hungarian Department of Biology and Ecology, Faculty of Biology and Geology, Babeș-Bolyai University, 5-7 Clinicilor St., 400006 Cluj-Napoca, Romania; (E.G.); (G.S.)
- Institute for Research-Development-Innovation in Applied Natural Sciences, Babeș-Bolyai University, 30 Fântânele St., 400294 Cluj-Napoca, Romania
| | - Michael G. Klein
- Department of Entomology, The Ohio State University, 1680 Madison Ave., Wooster, OH 44691, USA;
| | - Zsuzsanna Koncz
- Max-Planck Institut für Pflanzenzüchtungsforschung, Carl-von-Linné-Weg 10, D-50829 Köln, Germany;
| | | | - László Ötvös
- OLPE, LLC, Audubon, PA 19403-1965, USA;
- Institute of Medical Microbiology, Semmelweis University, H-1085 Budapest, Hungary
- Arrevus, Inc., Raleigh, NC 27612, USA
| | - Gyöngyi Székely
- Hungarian Department of Biology and Ecology, Faculty of Biology and Geology, Babeș-Bolyai University, 5-7 Clinicilor St., 400006 Cluj-Napoca, Romania; (E.G.); (G.S.)
- Institute for Research-Development-Innovation in Applied Natural Sciences, Babeș-Bolyai University, 30 Fântânele St., 400294 Cluj-Napoca, Romania
- Centre for Systems Biology, Biodiversity and Bioresources, Babeș-Bolyai University, 5-7 Clinicilor St., 400006 Cluj-Napoca, Romania
| | - Dávid Vozik
- Research Institute on Bioengineering, Membrane Technology and Energetics, Faculty of Engineering, University of Veszprem, H-8200 Veszprém, Hungary; or or
| | - László Makrai
- Department of Microbiology and Infectious Diseases, University of Veterinary Medicine, P.O. Box 22, H-1581 Budapest, Hungary;
- Correspondence: or (A.F.); (L.M.); Tel.: +36-(30)-490-9294 (A.F.); +36-(30)-271-2513 (L.M.)
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Zlitni A, Gowrishankar G, Steinberg I, Haywood T, Sam Gambhir S. Maltotriose-based probes for fluorescence and photoacoustic imaging of bacterial infections. Nat Commun 2020; 11:1250. [PMID: 32144257 PMCID: PMC7060353 DOI: 10.1038/s41467-020-14985-8] [Citation(s) in RCA: 66] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Accepted: 02/13/2020] [Indexed: 11/09/2022] Open
Abstract
Currently, there are no non-invasive tools to accurately diagnose wound and surgical site infections before they become systemic or cause significant anatomical damage. Fluorescence and photoacoustic imaging are cost-effective imaging modalities that can be used to noninvasively diagnose bacterial infections when paired with a molecularly targeted infection imaging agent. Here, we develop a fluorescent derivative of maltotriose (Cy7-1-maltotriose), which is shown to be taken up in a variety of gram-positive and gram-negative bacterial strains in vitro. In vivo fluorescence and photoacoustic imaging studies highlight the ability of this probe to detect infection, assess infection burden, and visualize the effectiveness of antibiotic treatment in E. coli-induced myositis and a clinically relevant S. aureus wound infection murine model. In addition, we show that maltotriose is an ideal scaffold for infection imaging agents encompassing better pharmacokinetic properties and in vivo stability than other maltodextrins (e.g. maltohexose).
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Affiliation(s)
- Aimen Zlitni
- Molecular Imaging Program at Stanford, Stanford University, Stanford, CA, 94305, USA
- Department of Radiology, Stanford University, Stanford, CA, 94305, USA
| | - Gayatri Gowrishankar
- Molecular Imaging Program at Stanford, Stanford University, Stanford, CA, 94305, USA
- Department of Radiology, Stanford University, Stanford, CA, 94305, USA
| | - Idan Steinberg
- Molecular Imaging Program at Stanford, Stanford University, Stanford, CA, 94305, USA
- Department of Radiology, Stanford University, Stanford, CA, 94305, USA
| | - Tom Haywood
- Molecular Imaging Program at Stanford, Stanford University, Stanford, CA, 94305, USA
- Department of Radiology, Stanford University, Stanford, CA, 94305, USA
| | - Sanjiv Sam Gambhir
- Molecular Imaging Program at Stanford, Stanford University, Stanford, CA, 94305, USA.
- Department of Radiology, Stanford University, Stanford, CA, 94305, USA.
- Department of Bioengineering, Department of Materials Science & Engineering, Stanford University, Stanford, CA, 94305, USA.
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Grand M, Blancato VS, Espariz M, Deutscher J, Pikis A, Hartke A, Magni C, Sauvageot N. Enterococcus faecalisMalR acts as a repressor of the maltose operons and additionally mediates their catabolite repression via direct interaction with seryl‐phosphorylated‐HPr. Mol Microbiol 2019; 113:464-477. [DOI: 10.1111/mmi.14431] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Revised: 11/13/2019] [Accepted: 11/19/2019] [Indexed: 12/26/2022]
Affiliation(s)
| | - Victor Sebastián Blancato
- Instituto de Biología Molecular y Celular de Rosario (IBR‐CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas Universidad Nacional de Rosario Rosario Argentina
| | - Martín Espariz
- Instituto de Biología Molecular y Celular de Rosario (IBR‐CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas Universidad Nacional de Rosario Rosario Argentina
| | - Josef Deutscher
- Micalis Institute, INRA, AgroParisTech, Université Paris‐Saclay Jouy‐en‐Josas France
- UMR 8261, CNRS, Université de Paris, Institut de Biologie Physico‐Chimique Paris France
| | - Andreas Pikis
- Center for Drug Evaluation and Research, Food and Drug Administration Silver Spring Maryland
- Microbial Biochemistry and Genetics Unit, Laboratory of Cell and Developmental Biology NIDCR, National Institutes of Health Bethesda Maryland
| | | | - Christian Magni
- Instituto de Biología Molecular y Celular de Rosario (IBR‐CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas Universidad Nacional de Rosario Rosario Argentina
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Grand M, Aubourg M, Pikis A, Thompson J, Deutscher J, Hartke A, Sauvageot N. Characterization of the gen locus involved in β-1,6-oligosaccharide utilization by Enterococcus faecalis. Mol Microbiol 2019; 112:1744-1756. [PMID: 31529727 DOI: 10.1111/mmi.14390] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/14/2019] [Indexed: 11/30/2022]
Abstract
The bicistronic genBA operon (formerly named celBA) of the opportunistic pathogen Enterococcus faecalis, encodes a 6-phospho-β-glucosidase (GenA) and a phosphotransferase system permease EIIC (GenB). It resembles the cel operon of Streptococcus pyogenes, which is implicated in the metabolism of cellobiose. However, genBA mutants grew normally on cellobiose, but not (genA) or only slowly (genB) on gentiobiose and amygdalin. The two glucosides were also found to be the main inducers of the operon, confirming that the encoded proteins are involved in the utilization of β-1,6- rather than β-1,4-linked oligosaccharides. Expression of the genBA operon is regulated by the transcriptional activator GenR, which is encoded by the gene upstream from genB. Thermal shift analysis showed that it binds gentiobiose-6'-P with a Kd of 0.04 mM and with lower affinity also other phospho-sugars. The GenR/gentiobiose-6'-P complex binds to the promoter region upstream from genB. The genBA promoter region contains a cre box and gel-shift experiments demonstrated that the operon is under negative control of the global carbon catabolite regulator CcpA. We also show that the orphan EIIC (GenB) protein needs the EIIA component of the putative OG1RF_10750-OG1RF_10755 operon situated elsewhere on the chromosome to form a functional PTS transporter.
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Affiliation(s)
- Maxime Grand
- Normandie Univ, UNICAEN, U2RM Stress/Virulence, Caen, 14000, France
| | - Marion Aubourg
- Normandie Univ, UNICAEN, U2RM Antibio-résistance et Pathologies équines, Caen, 14000, France
| | - Andreas Pikis
- Center for Drug Evaluation and Research, Food and Drug Administration, Silver Spring, MD, 20993, USA.,Microbial Biochemistry and Genetics Unit, Laboratory of Cell and Developmental Biology, NIDCR, National Institutes of Health, Bethesda, MD, 20892, USA
| | - John Thompson
- Microbial Biochemistry and Genetics Unit, Laboratory of Cell and Developmental Biology, NIDCR, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Josef Deutscher
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, 78350, Jouy-en-Josas, France.,UMR 8261, CNRS, Université Paris VII, Institut de Biologie Physico-Chimique, 75005, Paris, France
| | - Axel Hartke
- Normandie Univ, UNICAEN, U2RM Stress/Virulence, Caen, 14000, France
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Abstract
The genus Enterococcus comprises a ubiquitous group of Gram-positive bacteria that are of great relevance to human health for their role as major causative agents of health care-associated infections. The enterococci are resilient and versatile species able to survive under harsh conditions, making them well adapted to the health care environment. Two species cause the majority of enterococcal infections: Enterococcus faecalis and Enterococcus faecium Both species demonstrate intrinsic resistance to common antibiotics, such as virtually all cephalosporins, aminoglycosides, clindamycin, and trimethoprim-sulfamethoxazole. Additionally, a remarkably plastic genome allows these two species to readily acquire resistance to further antibiotics, such as high-level aminoglycoside resistance, high-level ampicillin resistance, and vancomycin resistance, either through mutation or by horizontal transfer of genetic elements conferring resistance determinants.
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Affiliation(s)
- Mónica García-Solache
- Department of Medicine, Rhode Island Hospital, Warren Alpert Medical School of Brown University, Providence, Rhode Island, USA
| | - Louis B Rice
- Department of Medicine, Rhode Island Hospital, Warren Alpert Medical School of Brown University, Providence, Rhode Island, USA
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17
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Latorre M, Quenti D, Travisany D, Singh KV, Murray BE, Maass A, Cambiazo V. The Role of Fur in the Transcriptional and Iron Homeostatic Response of Enterococcus faecalis. Front Microbiol 2018; 9:1580. [PMID: 30065712 PMCID: PMC6056675 DOI: 10.3389/fmicb.2018.01580] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Accepted: 06/25/2018] [Indexed: 01/23/2023] Open
Abstract
The ferric uptake regulator (Fur) plays a major role in controlling the expression of iron homeostasis genes in bacterial organisms. In this work, we fully characterized the capacity of Fur to reconfigure the global transcriptional network and influence iron homeostasis in Enterococcus faecalis. The characterization of the Fur regulon from E. faecalis indicated that this protein (Fur) regulated the expression of genes involved in iron uptake systems, conferring to the system a high level of efficiency and specificity to respond under different iron exposure conditions. An RNAseq assay coupled with a systems biology approach allowed us to identify the first global transcriptional network activated by different iron treatments (excess and limited), with and without the presence of Fur. The results showed that changes in iron availability activated a complex network of transcriptional factors in E. faecalis, among them global regulators such as LysR, ArgR, GalRS, and local regulators, LexA and CopY, which were also stimulated by copper and zinc treatments. The deletion of Fur impacted the expression of genes encoding for ABC transporters, energy production and [Fe-S] proteins, which optimized detoxification and iron uptake under iron excess and limitation, respectively. Finally, considering the close relationship between iron homeostasis and pathogenesis, our data showed that the absence of Fur increased the internal concentration of iron in the bacterium and also affected its ability to produce biofilm. These results open new alternatives in the field of infection mechanisms of E. faecalis.
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Affiliation(s)
- Mauricio Latorre
- Laboratorio de Bioinformática y Expresión Génica, Instituto de Nutrición y Tecnología de los Alimentos, Universidad de Chile, Santiago, Chile.,Mathomics, Center for Mathematical Modeling, Universidad de Chile, Santiago, Chile.,Center for Genome Regulation (Fondap 15090007), Universidad de Chile, Santiago, Chile.,Instituto de Ciencias de la Ingeniería, Universidad de O'Higgins, Rancagua, Chile
| | - Daniela Quenti
- Laboratorio de Bioinformática y Expresión Génica, Instituto de Nutrición y Tecnología de los Alimentos, Universidad de Chile, Santiago, Chile
| | - Dante Travisany
- Mathomics, Center for Mathematical Modeling, Universidad de Chile, Santiago, Chile.,Center for Genome Regulation (Fondap 15090007), Universidad de Chile, Santiago, Chile
| | - Kavindra V Singh
- Division of Infectious Diseases, Department of Internal Medicine, University of Texas Health Science Center at Houston, Houston, TX, United States.,Center for Antimicrobial Resistance and Microbial Genomics, McGovern Medical School, University of Texas Health Science Center at Houston (UTHealth), Houston, TX, United States
| | - Barbara E Murray
- Division of Infectious Diseases, Department of Internal Medicine, University of Texas Health Science Center at Houston, Houston, TX, United States.,Center for Antimicrobial Resistance and Microbial Genomics, McGovern Medical School, University of Texas Health Science Center at Houston (UTHealth), Houston, TX, United States
| | - Alejandro Maass
- Mathomics, Center for Mathematical Modeling, Universidad de Chile, Santiago, Chile.,Center for Genome Regulation (Fondap 15090007), Universidad de Chile, Santiago, Chile.,Department of Mathematical Engineering, Universidad de Chile, Santiago, Chile
| | - Verónica Cambiazo
- Laboratorio de Bioinformática y Expresión Génica, Instituto de Nutrición y Tecnología de los Alimentos, Universidad de Chile, Santiago, Chile.,Center for Genome Regulation (Fondap 15090007), Universidad de Chile, Santiago, Chile
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18
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Cheng P, Wang Y, Liang J, Wu Y, Wright A, Liao X. Exploratory Analysis of the Microbiological Potential for Efficient Utilization of Fiber Between Lantang and Duroc Pigs. Front Microbiol 2018; 9:1342. [PMID: 29988353 PMCID: PMC6023970 DOI: 10.3389/fmicb.2018.01342] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2018] [Accepted: 05/31/2018] [Indexed: 01/08/2023] Open
Abstract
There is growing interest in the use of unconventional feed ingredients containing higher dietary fiber for pig production due to increasing prices of cereal grains and the potential health benefits of dietary fiber on host animals. This study aimed to gain insight into the community-wide microbiome population between the Chinese native Lantang pigs and the commercial Duroc pigs to uncover the microbiological mechanisms for the degradation capacity of fiber in pigs. Utilizing the metagenomics approach, we compared the phylogeny and functional capacity of the fecal microbiome from approximately 150-day-old female Lantang and Duroc pigs fed a similar diet. The structure of the fecal microbial community from the two pig breeds was different at the genus level; the number of genes associated with fiber degradation was higher in Lantang pigs. Further analysis and prediction of their functions from the fecal microbiomes of the two pig breeds revealed that the degradation capacities of fiber, branched chain fatty acids, and oligosaccharides were higher in Lantang pigs. The ability of lignocellulose bonding modules and the transport capacities of xylose, L-arabinose, ribose and methyl galactose were also higher in Lantang pigs. Similarly, the metabolic capacities of xylose, ribose, and fucose and the potential effectiveness of the tricarboxylic acid cycle (TCA) and gene abundance in the hydrogen sink pathway were higher in the fecal microbiome from Lantang pigs. Lantang pigs have a higher capacity to utilize dietary fiber than Duroc pigs, and the differences in the capability to utilize dietary fiber between the indigenous and commercial pigs could be differences in the composition and biological function of the gut microbiota.
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Affiliation(s)
- Penghui Cheng
- College of Animal Science, South China Agricultural University, Guangzhou, China
| | - Yan Wang
- College of Animal Science, South China Agricultural University, Guangzhou, China
| | - Juanboo Liang
- Institute of Tropical Agriculture and Food Security, Universiti Putra Malaysia, Seri Kembangan, Malaysia
| | - Yinbao Wu
- College of Animal Science, South China Agricultural University, Guangzhou, China
| | - Andredenis Wright
- School of Animal and Comparative Biomedical Sciences, College of Agriculture and Life Sciences, University of Arizona, Tucson, AZ, United States
| | - Xindi Liao
- College of Animal Science, South China Agricultural University, Guangzhou, China
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Safety assessment and functional properties of four enterococci strains isolated from regional Argentinean cheese. Int J Food Microbiol 2018; 277:1-9. [PMID: 29669304 DOI: 10.1016/j.ijfoodmicro.2018.04.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Revised: 03/07/2018] [Accepted: 04/07/2018] [Indexed: 01/22/2023]
Abstract
The members of the Enterococcus genus are widely distributed in nature. Its strains have been extensively reported to be present in plant surfaces, soil, water and food. In an attempt to assess their potential application in food industry, four Enterococcus faecium group-strains recently isolated from Argentinean regional cheese products were evaluated using a combination of whole genome analyses and in vivo assays. In order to identify these microorganisms at species level, in silico analyses using their newly reported sequences were conducted. The average nucleotide identity (ANI), in silico DNA-DNA hybridization, and phylogenomic trees constructed using core genome data allowed IQ110, GM70 and GM75 strains to be classified as E. faecium while IQ23 strain was identified as E. durans. Besides their common origin, the strains showed differences in their genetic structure and mobile genetic element content. Furthermore, it was possible to determine the absence or presence of specific features related to growth in milk, cheese ripening, probiotic capability and gut adaptation including sugar, amino acid, and peptides utilization, flavor compound production, bile salt tolerance as well as biogenic amine production. Remarkably, all strains encoded for peptide permeases, maltose utilization, bile salt tolerance, diacetyl and tyramine production genes. On the other hand, some variability was observed regarding citrate and lactose utilization, esterase, and cell wall-associated proteinase. In addition, while strains were predicted to be non-human pathogens by the in silico inspection of pathogenicity and virulence factors, only the GM70 strain proved to be non-virulent in Galleria mellonella model. In conclusion, we propose that, in order to improve the rational selection of strains for industrial applications, a holistic approach involving a comparative genomic analysis of positive and negative features as well as in vivo evaluation of virulence behavior should be performed.
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Enzymes Required for Maltodextrin Catabolism in Enterococcus faecalis Exhibit Novel Activities. Appl Environ Microbiol 2017; 83:AEM.00038-17. [PMID: 28455338 DOI: 10.1128/aem.00038-17] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2017] [Accepted: 04/19/2017] [Indexed: 01/16/2023] Open
Abstract
Maltose and maltodextrins are formed during the degradation of starch or glycogen. Maltodextrins are composed of a mixture of maltooligosaccharides formed by α-1,4- but also some α-1,6-linked glucosyl residues. The α-1,6-linked glucosyl residues are derived from branching points in the polysaccharides. In Enterococcus faecalis, maltotriose is mainly transported and phosphorylated by a phosphoenolpyruvate:carbohydrate phosphotransferase system. The formed maltotriose-6″-phosphate is intracellularly dephosphorylated by a specific phosphatase, MapP. In contrast, maltotetraose and longer maltooligosaccharides up to maltoheptaose are taken up without phosphorylation via the ATP binding cassette transporter MdxEFG-MsmX. We show that the maltose-producing maltodextrin hydrolase MmdH (GenBank accession no. EFT41964) in strain JH2-2 catalyzes the first catabolic step of α-1,4-linked maltooligosaccharides. The purified enzyme converts even-numbered α-1,4-linked maltooligosaccharides (maltotetraose, etc.) into maltose and odd-numbered (maltotriose, etc.) into maltose and glucose. Inactivation of mmdH therefore prevents the growth of E. faecalis on maltooligosaccharides ranging from maltotriose to maltoheptaose. Surprisingly, MmdH also functions as a maltogenic α-1,6-glucosidase, because it converts the maltotriose isomer isopanose into maltose and glucose. In addition, E. faecalis contains a glucose-producing α-1,6-specific maltodextrin hydrolase (GenBank accession no. EFT41963, renamed GmdH). This enzyme converts panose, another maltotriose isomer, into glucose and maltose. A gmdH mutant had therefore lost the capacity to grow on panose. The genes mmdH and gmdH are organized in an operon together with GenBank accession no. EFT41962 (renamed mmgT). Purified MmgT transfers glucosyl residues from one α-1,4-linked maltooligosaccharide molecule to another. For example, it catalyzes the disproportionation of maltotriose by transferring a glucosyl residue to another maltotriose molecule, thereby forming maltotetraose and maltose together with a small amount of maltopentaose.IMPORTANCE The utilization of maltodextrins by Enterococcus faecalis has been shown to increase the virulence of this nosocomial pathogen. However, little is known about how this organism catabolizes maltodextrins. We identified two enzymes involved in the metabolism of various α-1,4- and α-1,6-linked maltooligosaccharides. We found that one of them functions as a maltose-producing α-glucosidase with relaxed linkage specificity (α-1,4 and α-1,6) and exo- and endoglucosidase activities. A third enzyme, which resembles amylomaltase, exclusively transfers glucosyl residues from one maltooligosaccharide molecule to another. Similar enzymes are present in numerous other Firmicutes, such as streptococci and lactobacilli, suggesting that these organisms follow the same maltose degradation pathway as E. faecalis.
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