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Laekas-Hameder M, Daigle F. Only time will tell: lipopolysaccharide glycoform and biofilm-formation kinetics in Salmonella species and Escherichia coli. J Bacteriol 2024:e0031824. [PMID: 39315775 DOI: 10.1128/jb.00318-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/25/2024] Open
Abstract
In Gram-negative bacteria, LPS (lipopolysaccharide) has been thoroughly characterized and has been shown to play a major role in pathogenesis and bacterial defense. In Salmonella and Escherichia coli, LPS also influences biofilm development. However, the overall role of LPS glycoform in biofilm formation has not been conclusively settled, as there is a lack of consensus on the topic. Some studies show that LPS mutants produce less biofilm biomass than the wild-type strains, while others show that they produce more. This review summarizes current knowledge of LPS biosynthesis and explores the impact of defective steps on biofilm-related characteristics, such as motility, adhesion, auto-aggregation, and biomass production in Salmonella and E. coli. Overall, motility tends to decrease, while adhesion and auto-aggregation phenotypes tend to increase in most LPS-mutant strains. Interestingly, biofilm biomass of various LPS mutants revealed a clear pattern dependent on biofilm maturation time. Incubation times of less than 24 h resulted in a biofilm-defective phenotype compared to the wild-type, while incubation exceeding 24 h led to significantly higher levels of biofilm production. This explains conflicting results found in reports describing the same LPS mutations. It is therefore critical to consider the effect of biofilm maturation time to ascertain the effects of LPS glycoform on biofilm phenotype. Underlying reasons for such changes in biofilm kinetics may include changes in signalling systems affecting biofilm maturation and composition, and dynamic LPS modifications. A better understanding of the role of LPS in the evolution and modification of biofilms is crucial for developing strategies to disperse biofilms.
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Affiliation(s)
- Magdalena Laekas-Hameder
- Département de microbiologie, infectiologie et immunologie, Université de Montréal, Montréal, Québec, Canada
| | - France Daigle
- Département de microbiologie, infectiologie et immunologie, Université de Montréal, Montréal, Québec, Canada
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Panich J, Dudebout EM, Wadhwa N, Blair DF. Swashing motility: A novel propulsion-independent mechanism for surface migration in Salmonella and E. coli. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.08.21.609010. [PMID: 39229098 PMCID: PMC11370582 DOI: 10.1101/2024.08.21.609010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 09/05/2024]
Abstract
Bacterial motility over surfaces is crucial for colonization, biofilm formation, and pathogenicity. Surface motility in Escherichia coli and Salmonella enterica is traditionally believed to rely on flagellar propulsion. Here, we report a novel mode of motility, termed "swashing," where these bacteria migrate on agar surfaces without functional flagella. Mutants lacking flagellar filaments and motility proteins exhibit rapid surface migration comparable to wild-type strains. Unlike previously described sliding motility, swashing is inhibited by surfactants and requires fermentable sugars. We propose that the fermentation of sugars at the colony edge produces osmolytes, creating local osmotic gradients that draw water from the agar, forming a fluid bulge that propels the colony forward. Our findings challenge the established view that flagellar propulsion is required for surface motility in E. coli and Salmonella, and highlight the role of a fermentation in facilitating bacterial spreading. This discovery expands our understanding of bacterial motility, offering new insights into bacterial adaptive strategies in diverse environments.
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Affiliation(s)
- Justin Panich
- School of Biological Sciences, University of Utah, Salt Lake City, UT 84112
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720
| | - Eric M Dudebout
- Biodesign Center for Mechanisms of Evolution, Arizona State University, Tempe, AZ 85287, USA
| | - Navish Wadhwa
- Biodesign Center for Mechanisms of Evolution, Arizona State University, Tempe, AZ 85287, USA
- Center for Biological Physics and Department of Physics, Arizona State University, Tempe, AZ 85287
| | - David F Blair
- School of Biological Sciences, University of Utah, Salt Lake City, UT 84112
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Sheng H, Ndeddy Aka RJ, Wu S. Lipopolysaccharide Core Truncation in Invasive Escherichia coli O157:H7 ATCC 43895 Impairs Flagella and Curli Biosynthesis and Reduces Cell Invasion Ability. Int J Mol Sci 2024; 25:9224. [PMID: 39273173 PMCID: PMC11394844 DOI: 10.3390/ijms25179224] [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: 08/05/2024] [Revised: 08/22/2024] [Accepted: 08/24/2024] [Indexed: 09/15/2024] Open
Abstract
Escherichia coli O157:H7 (E. coli O157) is known for causing severe foodborne illnesses such as hemorrhagic colitis and hemolytic uremic syndrome. Although E. coli O157 is typically regarded as an extracellular pathogen and a weak biofilm producer, some E. coli O157 strains, including a clinical strain ATCC 43895, exhibit a notable ability to invade bovine crypt cells and other epithelial cells, as well as to form robust biofilm. This invasive strain persists in the bovine host significantly longer than non-invasive strains. Various surface-associated factors, including lipopolysaccharides (LPS), flagella, and other adhesins, likely contribute to this enhanced invasiveness and biofilm formation. In this study, we constructed a series of LPS-core deletion mutations (waaI, waaG, waaF, and waaC) in E. coli O157 ATCC 43895, resulting in stepwise truncations of the LPS. This approach enabled us to investigate the effects on the biosynthesis of key surface factors, such as flagella and curli, and the ability of this invasive strain to invade host cells. We confirmed the LPS structure and found that all LPS-core mutants failed to form biofilms, highlighting the crucial role of core oligosaccharides in biofilm formation. Additionally, the LPS inner-core mutants ΔwaaF and ΔwaaC lost the ability to produce flagella and curli. Furthermore, these inner-core mutants exhibited a dramatic reduction in adherence to and invasion of epithelial cells (MAC-T), showing an approximately 100-fold decrease in cell invasion compared with the outer-core mutants (waaI and waaG) and the wild type. These findings underscore the critical role of LPS-core truncation in impairing flagella and curli biosynthesis, thereby reducing the invasion capability of E. coli O157 ATCC 43895.
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Affiliation(s)
- Haiqing Sheng
- Department of Chemical and Biological Engineering, University of Idaho, Moscow, ID 83844, USA
| | - Robinson J Ndeddy Aka
- Department of Chemical and Biological Engineering, University of Idaho, Moscow, ID 83844, USA
| | - Sarah Wu
- Department of Chemical and Biological Engineering, University of Idaho, Moscow, ID 83844, USA
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Lyu C, Hu H, Cai L, He S, Xu X, Zhou G, Wang H. A trans-acting sRNA SaaS targeting hilD, cheA and csgA to inhibit biofilm formation of S. Enteritidis. J Adv Res 2024:S2090-1232(24)00232-7. [PMID: 38852803 DOI: 10.1016/j.jare.2024.06.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2024] [Revised: 05/28/2024] [Accepted: 06/04/2024] [Indexed: 06/11/2024] Open
Abstract
INTRODUCTION Salmonella Enteritidis has brought great harm to public health, animal production and food safety worldwide. The biofilm formed by Salmonella Enteritidis plays a critical role in microbial cross-contamination. Small non-coding RNAs (sRNAs) have been demonstrated to be responsible for regulating the formation of biofilm. The sRNA SaaS has been identified previously, that promotes pathogenicity by regulating invasion and virulence factors. However, whether the SaaS is implicated in regulating biofilm formation in abiotic surfaces remains unclear. OBJECTIVES This study aimed to clarify the effect of SaaS in Salmonella Enteritidis and explore the modulatory mechanism on the biofilm formation. METHODS Motility characteristics and total biomass of biofilm of test strains were investigated by the phenotypes in three soft agar plates and crystal violet staining in polystyrene microplates. Studies of microscopic structure and extracellular polymeric substances (EPS) of biofilm on solid surfaces were carried out using confocal laser scanning microscope (CLSM) and Raman spectra. Transcriptomics and proteomics were applied to analyze the changes of gene expression and EPS component. The RNA-protein pull-down and promoter-reporter β-galactosidase activity assays were employed to analyze RNA binding proteins and identify target mRNAs, respectively. RESULTS SaaS inhibits biofilm formation by repressing the adhesion potential and the secretion of EPS components. Integration of transcriptomics and proteomics analysis revealed that SaaS strengthened the expression of the flagellar synthesis system and downregulated the expression of curli amyloid fibers. Furthermore, RNA-protein pull-down interactome datasets indicated that SaaS binds to Hfq (an RNA molecular chaperone protein, known as a host factor for phage Qbeta RNA replication) uniquely among 193 candidate proteins, and promoter-reporter β-galactosidase activity assay confirmed target mRNAs including hilD, cheA, and csgA. CONCLUSION SaaS inhibits the properties of bacterial mobility, perturbs the secretion of EPS, and contributes to the inhibition of biofilm formation by interacting with target mRNA (hilD, cheA, and csgA) through the Hfq-mediated pathway.
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Affiliation(s)
- Chongyang Lyu
- State Key Laboratory of Meat Quality Control and Cultured Meat Development, College of Food Science and Technology, Nanjing Agricultural University, Nanjing, People's Republic of China
| | - Haijing Hu
- State Key Laboratory of Meat Quality Control and Cultured Meat Development, College of Food Science and Technology, Nanjing Agricultural University, Nanjing, People's Republic of China
| | - Linlin Cai
- State Key Laboratory of Meat Quality Control and Cultured Meat Development, College of Food Science and Technology, Nanjing Agricultural University, Nanjing, People's Republic of China
| | - Shuwen He
- State Key Laboratory of Meat Quality Control and Cultured Meat Development, College of Food Science and Technology, Nanjing Agricultural University, Nanjing, People's Republic of China
| | - Xinglian Xu
- State Key Laboratory of Meat Quality Control and Cultured Meat Development, College of Food Science and Technology, Nanjing Agricultural University, Nanjing, People's Republic of China
| | - Guanghong Zhou
- State Key Laboratory of Meat Quality Control and Cultured Meat Development, College of Food Science and Technology, Nanjing Agricultural University, Nanjing, People's Republic of China
| | - Huhu Wang
- State Key Laboratory of Meat Quality Control and Cultured Meat Development, College of Food Science and Technology, Nanjing Agricultural University, Nanjing, People's Republic of China; College of Food Science and Pharmacy, Xinjiang Agricultural University, Urumqi, Xinjiang, People's Republic of China.
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Zhang P, Huguet-Tapia J, Peng Z, Liu S, Obasa K, Block AK, White FF. Genome analysis and hyphal movement characterization of the hitchhiker endohyphal Enterobacter sp. from Rhizoctonia solani. Appl Environ Microbiol 2024; 90:e0224523. [PMID: 38319098 PMCID: PMC10952491 DOI: 10.1128/aem.02245-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Accepted: 01/05/2024] [Indexed: 02/07/2024] Open
Abstract
Bacterial-fungal interactions are pervasive in the rhizosphere. While an increasing number of endohyphal bacteria have been identified, little is known about their ecology and impact on the associated fungal hosts and the surrounding environment. In this study, we characterized the genome of an Enterobacter sp. Crenshaw (En-Cren), which was isolated from the generalist fungal pathogen Rhizoctonia solani, and examined the genetic potential of the bacterium with regard to the phenotypic traits associated with the fungus. Overall, the En-Cren genome size was typical for members of the genus and was capable of free-living growth. The genome was 4.6 MB in size, and no plasmids were detected. Several prophage regions and genomic islands were identified that harbor unique genes in comparison with phylogenetically closely related Enterobacter spp. Type VI secretion system and cyanate assimilation genes were identified from the bacterium, while some common heavy metal resistance genes were absent. En-Cren contains the key genes for indole-3-acetic acid (IAA) and phenylacetic acid (PAA) biosynthesis, and produces IAA and PAA in vitro, which may impact the ecology or pathogenicity of the fungal pathogen in vivo. En-Cren was observed to move along hyphae of R. solani and on other basidiomycetes and ascomycetes in culture. The bacterial flagellum is essential for hyphal movement, while other pathways and genes may also be involved.IMPORTANCEThe genome characterization and comparative genomics analysis of Enterobacter sp. Crenshaw provided the foundation and resources for a better understanding of the ecology and evolution of this endohyphal bacteria in the rhizosphere. The ability to produce indole-3-acetic acid and phenylacetic acid may provide new angles to study the impact of phytohormones during the plant-pathogen interactions. The hitchhiking behavior of the bacterium on a diverse group of fungi, while inhibiting the growth of some others, revealed new areas of bacterial-fungal signaling and interaction, which have yet to be explored.
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Affiliation(s)
- Peiqi Zhang
- Department of Plant Pathology, University of Florida, Gainesville, Florida, USA
| | - Jose Huguet-Tapia
- Department of Plant Pathology, University of Florida, Gainesville, Florida, USA
| | - Zhao Peng
- Department of Plant Pathology, University of Florida, Gainesville, Florida, USA
- College of Plant Protection, Jilin Agricultural University, Changchun, Jilin, China
| | - Sanzhen Liu
- Department of Plant Pathology, Kansas State University, Manhattan, Kansas, USA
| | - Ken Obasa
- Department of Plant Pathology, University of Florida, Gainesville, Florida, USA
- High Plains Plant Disease Diagnostic Lab, Texas A&M AgriLife Extension Service, Amarillo, Texas, USA
| | - Anna K. Block
- Chemistry Research Unit, US Department of Agriculture-Agricultural Research Service, Gainesville, Florida, USA
| | - Frank F. White
- Department of Plant Pathology, University of Florida, Gainesville, Florida, USA
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Choi J, Yadav S, Vaddu S, Thippareddi H, Kim WK. In vitro and in vivo evaluation of tannic acid as an antibacterial agent in broilers infected with Salmonella Typhimurium. Poult Sci 2023; 102:102987. [PMID: 37844525 PMCID: PMC10585643 DOI: 10.1016/j.psj.2023.102987] [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: 05/11/2023] [Revised: 07/25/2023] [Accepted: 07/26/2023] [Indexed: 10/18/2023] Open
Abstract
This study was conducted to evaluate tannic acid (TA) as an antibacterial agent against Salmonella Typhimurium in in vitro and in vivo chicken models. The TA formed an inhibitory zone against Salmonella enterica serotypes including S. Typhimurium, S. Enteritidis, and S. Infantis. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of TA against Salmonella Typhimurium nalidixic acid resistant strain (STNR) were determined as 40 and 700 μg/mL, respectively. Sublethal doses of TA (5, 10, and 20 μg/mL) restricted swimming and swarming motility and biofilm formation of STNR compared to the control group (0 μg/mL) (P < 0.05). The TA-bovine serum albumin (BSA) complex formed at simulated gastric pH (pH 3.75) was hydrolyzed at pH 6.75 and 7.25 (P < 0.05), and the hydrolysis of the TA-BSA complex was stronger at pH 7.25 compared to the pH 6.75 (P < 0.05). The inhibitory zone of the TA-BSA complex against STNR at pH 6.75 was lower than TA without BSA at 30 and 60 min (P < 0.05), but not at 120 min (P > 0.1). The inhibitory zone of the TA-BSA complex against STNR at pH 7.25 was not decreased at 0, 30, and 60 min compared to TA without BSA (P > 0.1). The recovery rate of TA was 83, 54.8, 10.5, and 19.6% in the gizzard, jejunum, ileum, and ceca, respectively, in broiler chickens. The STNR-infected broilers fed 0.25 g/kg of TA had significantly lower unweighted beta diversity distance compared to the sham-challenged control (SCC) and challenged controlled (CC) group on D 21. TA supplementation linearly (P < 0.05) and quadratically (tendency; P = 0.071) reduced relative abundance of the family Peptostreptococcaceae in broilers infected with STNR on D 7. TA supplementation linearly (P < 0.05) and quadratically (tendency; P = 0.06) increased the relative abundance of the family Erysipelotrichaceae in broilers infected with STNR on D 21. Therefore, TA has potential to be used as an antibacterial agent against the S. Typhimurium infection in broilers.
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Affiliation(s)
- Janghan Choi
- Department of Poultry Science, University of Georgia, Athens, GA 30602, USA
| | - Sudhir Yadav
- Department of Poultry Science, University of Georgia, Athens, GA 30602, USA
| | - Sasikala Vaddu
- Department of Poultry Science, University of Georgia, Athens, GA 30602, USA
| | | | - Woo Kyun Kim
- Department of Poultry Science, University of Georgia, Athens, GA 30602, USA.
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Saleh DO, Horstmann JA, Giralt-Zúñiga M, Weber W, Kaganovitch E, Durairaj AC, Klotzsch E, Strowig T, Erhardt M. SPI-1 virulence gene expression modulates motility of Salmonella Typhimurium in a proton motive force- and adhesins-dependent manner. PLoS Pathog 2023; 19:e1011451. [PMID: 37315106 DOI: 10.1371/journal.ppat.1011451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Accepted: 06/01/2023] [Indexed: 06/16/2023] Open
Abstract
Both the bacterial flagellum and the evolutionary related injectisome encoded on the Salmonella pathogenicity island 1 (SPI-1) play crucial roles during the infection cycle of Salmonella species. The interplay of both is highlighted by the complex cross-regulation that includes transcriptional control of the flagellar master regulatory operon flhDC by HilD, the master regulator of SPI-1 gene expression. Contrary to the HilD-dependent activation of flagellar gene expression, we report here that activation of HilD resulted in a dramatic loss of motility, which was dependent on the presence of SPI-1. Single cell analyses revealed that HilD-activation triggers a SPI-1-dependent induction of the stringent response and a substantial decrease in proton motive force (PMF), while flagellation remains unaffected. We further found that HilD activation enhances the adhesion of Salmonella to epithelial cells. A transcriptome analysis revealed a simultaneous upregulation of several adhesin systems, which, when overproduced, phenocopied the HilD-induced motility defect. We propose a model where the SPI-1-dependent depletion of the PMF and the upregulation of adhesins upon HilD-activation enable flagellated Salmonella to rapidly modulate their motility during infection, thereby enabling efficient adhesion to host cells and delivery of effector proteins.
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Affiliation(s)
- Doaa Osama Saleh
- Institute for Biology/Molecular Microbiology, Humboldt-Universität zu Berlin, Berlin, Germany
- Department of Microbiology and Immunology, Faculty of Pharmacy, Ain Shams University, Cairo, Egypt
| | - Julia A Horstmann
- Junior Research Group Infection Biology of Salmonella, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - María Giralt-Zúñiga
- Institute for Biology/Molecular Microbiology, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Willi Weber
- Institute for Biology, Experimental Biophysics/Mechanobiology, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Eugen Kaganovitch
- Max Planck Institute for Terrestrial Microbiology and Center for Synthetic Microbiology (SYNMIKRO), Marburg, Germany
| | - Abilash Chakravarthy Durairaj
- Junior Research Group Infection Biology of Salmonella, Helmholtz Centre for Infection Research, Braunschweig, Germany
- Department of Microbial Immune Regulation, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Enrico Klotzsch
- Institute for Biology, Experimental Biophysics/Mechanobiology, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Till Strowig
- Department of Microbial Immune Regulation, Helmholtz Centre for Infection Research, Braunschweig, Germany
- Cluster of Excellence RESIST (EXC 2155), Hannover Medical School, Hannover, Germany
| | - Marc Erhardt
- Institute for Biology/Molecular Microbiology, Humboldt-Universität zu Berlin, Berlin, Germany
- Max Planck Unit for the Science of Pathogens, Berlin, Germany
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You Y, Ye F, Mao W, Yang H, Lai J, Deng S. An overview of the structure and function of the flagellar hook FlgE protein. World J Microbiol Biotechnol 2023; 39:126. [PMID: 36941455 DOI: 10.1007/s11274-023-03568-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Accepted: 03/04/2023] [Indexed: 03/23/2023]
Abstract
The flagellum is an important organelle for the survival of bacteria and consists of a basal body, hook, and filament. The FlgE protein is the subunit of the hook that connects the basal body and the filament and determines the motility of bacteria. Also, flgE gene plays an essential role in flagellar biosynthesis, swimming ability and biofilm formation. Although the intact flagella and the major component filament have been extensively studied, so far, little is known about the comprehensive understanding of flagellar hook and FlgE. Here in this review, we summarize the structures of flagellar hook and its subunit FlgE in various species and physiological functions of FlgE, including the hook assembly, the structural characteristics of flagellar hook, the mechanical properties of hook, and the similarities and differences between FlgE (hook) and FlgG (distal rod), with special attention on the interaction of FlgE with other molecules, the antigenicity and pro-inflammatory effect of FlgE, and cross-linking of FlgE in spirochetes. We hope our summary of this review could provide a better understanding of the FlgE protein and provide some useful information for developing new effective antibacterial drugs in the future work.
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Affiliation(s)
- Yu You
- Biopharmaceutical Research Institute, West China Hospital, Sichuan University, Chengdu, 610041, China.
| | - Fei Ye
- Department of Laboratory Medicine, West China Hospital, Sichuan University, Chengdu, 610041, China
| | - Wei Mao
- Biopharmaceutical Research Institute, West China Hospital, Sichuan University, Chengdu, 610041, China
| | - Hong Yang
- Biopharmaceutical Research Institute, West China Hospital, Sichuan University, Chengdu, 610041, China
| | - Jijia Lai
- Department of Laboratory Medicine, Hospital of Chengdu Office of People's Government of Tibetan Autonomous Region, Chengdu, 610041, China
| | - Shun Deng
- Sichuan Province Orthopedic Hospital, 132 West First Section First Ring Road, Chengdu, 610041, China
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9
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Resistance Mechanism and Physiological Effects of Microcin Y in Salmonella enterica subsp. enterica Serovar Typhimurium. Microbiol Spectr 2022; 10:e0185922. [PMID: 36453909 PMCID: PMC9769762 DOI: 10.1128/spectrum.01859-22] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Salmonella bacteria pose a significant threat to animal husbandry and human health due to their virulence and multidrug resistance. The lasso peptide MccY is a recently discovered antimicrobial peptide that acts against various serotypes of Salmonella. In this study, we further explore the resistance mechanism and activity of MccY. Mutants of Ton system genes, including tonB, exbB, and exbD, in Salmonella enterica subsp. enterica serovar Typhimurium were constructed, and the MICs to MccY exhibited significant increases in these deletion mutants compared to the MIC of the parent strain. Subsequently, MccY resistance was quantitatively analyzed, and these mutants also showed greatly reduced rates of killing, even with a high concentration of MccY. In addition, a minimal medium with low iron environment enhanced the sensitivity of these mutants to MccY. Measurements of a series of physiological indicators, including iron utilization, biofilm formation, and motility, demonstrated that MccY may decrease the virulence of S. Typhimurium. Transcriptomic analysis showed that iron utilization, biofilm formation, flagellar assembly, and virulence-related genes were downregulated to varying degrees when S. Typhimurium was treated with MccY. In conclusion, deletion of Ton system genes resulted in resistance to MccY and the susceptibility of these mutants to MccY was increased and differed under a low-iron condition. This lasso peptide can alter multiple physiological properties of S. Typhimurium. Our study will contribute to improve the knowledge and understanding of the mechanism of MccY resistance in Salmonella strains. IMPORTANCE The resistance of Salmonella to traditional antibiotics remains a serious challenge. Novel anti-Salmonella drugs are urgently needed to address the looming crisis. The newly identified antimicrobial peptide MccY shows broad prospects for development and application because of its obvious antagonistic effect on various serotypes of Salmonella. However, our previous study showed that the peptide could confer resistance to Salmonella by disrupting the receptor gene fhuA. In this study, we further explored the potential resistance mechanism of MccY and demonstrated the importance of the Salmonella Ton complex for MccY transport. Disruption in Ton system genes resulted in S. Typhimurium resistance to this peptide, and MccY could alter multiple bacterial physiological properties. In summary, this study further explored the resistance mechanism and antibacterial effect of MccY in S. Typhimurium and provided a scientific basis for its development and application.
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10
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Genome-wide analysis of fitness factors in uropathogenic Escherichia coli in a pig urinary tract infection model. Microbiol Res 2022; 265:127202. [PMID: 36167007 DOI: 10.1016/j.micres.2022.127202] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Revised: 08/24/2022] [Accepted: 09/13/2022] [Indexed: 11/20/2022]
Abstract
Uropathogenic Escherichia coli (UPEC) is the primary cause of urinary tract infections (UTIs) in animals and humans. We applied Transposon-Directed Insertion Site sequencing (TraDIS) to determine the fitness genes in two well-characterized UPEC strains, UTI89 and CFT073, in order to identify fitness factors during UTI in a pig model. This novel animal model better reflects the course of UTI in humans than the commonly used mouse model, and facilitates the differentiation between sessile and planktonic UPEC populations. A total of 854 and 483 genes in UTI89 and CFT073, respectively, were predicted to contribute to growth in pig urine, and 1257 and 764, were scored as required for colonization of the bladder. The combined list of fitness genes for growth in urine and cystitis contained 741 (UTI89) and 439 (CFT073) genes. The essential genes for growth on LB agar media supplemented with kanamycin and the fitness factors during growth in human urine were also analyzed in CFT073. A total of 457 essential genes were identified and the pool of fitness genes for growth in human urine included 215 genes. The gene rfaG, which is involved in lipopolysaccharide biosynthesis, was included in all the fitness-gene-lists and was further confirmed to be relevant for all the conditions tested regardless of the host and the strain. Thus, this gene may represent a promising target for the development of new therapeutic strategies against UTI UPEC-associated. Besides this important observation, the study revealed strain-specific differences in gene-essentiality as well as in the fitness-gene-repertoire for growth in human urine and UTI of the pig model, and it identified novel factors required for UPEC-induced UTIs.
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K.C N, Noatia L, Priyadarshini S, M P, Gali JM, Ali MA, Behera S, Sharma B, Roychoudhury P, Kumar A, Behera P. Recoding anaerobic regulator fnr of Salmonella Typhimurium attenuates it's pathogenicity. Microb Pathog 2022; 168:105591. [DOI: 10.1016/j.micpath.2022.105591] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Revised: 05/12/2022] [Accepted: 05/13/2022] [Indexed: 11/28/2022]
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12
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Yan W, Fu X, Gao Y, Shi L, Liu Q, Yang W, Feng J. Synthesis, antibacterial evaluation, and safety assessment of CuS NPs against Pectobacterium carotovorum subsp. carotovorum. PEST MANAGEMENT SCIENCE 2022; 78:733-742. [PMID: 34689404 DOI: 10.1002/ps.6686] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2021] [Revised: 09/03/2021] [Accepted: 10/24/2021] [Indexed: 06/13/2023]
Abstract
BACKGROUND Copper agents have been widely used in crop protection because of their unique mechanism against resistant pathogenic bacteria; however, their application brings environmental pollution and biosafety problems. Therefore, environmentally friendly copper agents have attracted attention. In this study, copper sulfide nanoparticles (CuS NPs) were prepared, characterized, analyzed for antibacterial activity and safety. RESULTS Characterization results showed that the prepared pure CuS NPs have flake nanostructures, hexagonal crystal system, and size range from 40 to 60 nm. These CuS NPs exerted excellent antibacterial effects [median effective concentration (EC50 ) = 17 mg L-1 ] against Pectobacterium carotovorum subsp. carotovorum (Pcc) in vitro and can effectively delay and reduce bacterial infection in vivo. Antibacterial mechanism analysis revealed that CuS NPs can increase the levels of reactive oxygen species (ROS) and lipid peroxidation and destroy the structure of bacterial cells as observed through scanning electron microscopy (SEM) and Fourier-transform infrared (FTIR) spectroscopy. These NPs can also inhibit the motility of Pcc. At 7 and 14 days, the 50% lethal concentrations (LC50 ) of CuS NPs against earthworms were 1136 and 783 mg kg-1 , respectively, indicating their low acute toxicity to earthworms and environmental friendliness. Furthermore, the cells (L02) treated by CuS NPs showed relatively high cell viability (> 96%) and low apoptosis rate (only 5.2%), proving that CuS NPs had low cytotoxicity. CONCLUSION Compared with commercial dicopper chloride trihydroxide (Cu2 (OH)3 Cl), CuS NPs could be used as a highly effective, lowly toxic, and environmentally friendly antibacterial agent. © 2021 Society of Chemical Industry.
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Affiliation(s)
- Weiyao Yan
- School of Horticulture and Plant Protection, Yangzhou University, Yangzhou, China
| | - Xuan Fu
- Medical College, Yangzhou University, Yangzhou, China
| | - Yuan Gao
- Medical College, Yangzhou University, Yangzhou, China
| | - Liyin Shi
- School of Horticulture and Plant Protection, Yangzhou University, Yangzhou, China
| | - Qi Liu
- Medical College, Yangzhou University, Yangzhou, China
| | - Wenchao Yang
- School of Horticulture and Plant Protection, Yangzhou University, Yangzhou, China
| | - Jianguo Feng
- School of Horticulture and Plant Protection, Yangzhou University, Yangzhou, China
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Ge H, Zhang K, Gu D, Chen X, Wang X, Li G, Zhu H, Chang Y, Zhao G, Pan Z, Jiao X, Hu M. The rfbN gene of Salmonella Typhimurium mediates phage adsorption by modulating biosynthesis of lipopolysaccharide. Microbiol Res 2021; 250:126803. [PMID: 34146940 DOI: 10.1016/j.micres.2021.126803] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2021] [Revised: 05/27/2021] [Accepted: 05/31/2021] [Indexed: 01/21/2023]
Abstract
The study of the interaction mechanism between bacteriophage and host is helpful in promoting development of bacteriophage applications. The mechanism of the interaction with the phage was studied by constructing the rfbN gene deletion and complemented with strains of Salmonella enterica subspecies enterica serovar Typhimurium (Salmonella Typhimurium, S. Typhimurium) D6. The rfbN gene deletion strain could not be lysed by phage S55 and led to a disorder of lipopolysaccharide (LPS) biosynthesis, which changed from the smooth type to rough type. Also, the RfbN protein lacking any of the three-segment amino acid (aa) sequences (90-120 aa, 121-158 aa, and 159-194 aa) produces the same result. Transmission electron microscopy and confocal microscopy assays demonstrated that phage S55 dramatically reduced adsorption to the rfbN deletion strain as compared to the wild strain D6. After co-incubation of the S55 with the purified smooth LPS, D6 could not be lysed, indicating that the smooth LPS binds to the S55 in vitro and then inhibits the cleavage activity of the S55. To sum up, the rfbN gene affects phage adsorption by regulating LPS synthesis. Furthermore, the functioning of the RfbN protein requires the involvement of multiple structures. To the best of our knowledge, this study is the first report of the involvement of the bacterial rfbN gene involved in the phage-adsorption process.
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Affiliation(s)
- Haojie Ge
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, 225009, Jiangsu, China; Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou, 225009, Jiangsu, China
| | - Kai Zhang
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, 225009, Jiangsu, China; Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou, 225009, Jiangsu, China
| | - Dan Gu
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, 225009, Jiangsu, China; Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou, 225009, Jiangsu, China
| | - Xiang Chen
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, 225009, Jiangsu, China; Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou, 225009, Jiangsu, China
| | - Xin Wang
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, 225009, Jiangsu, China; Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou, 225009, Jiangsu, China
| | - Guiqin Li
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, 225009, Jiangsu, China; Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou, 225009, Jiangsu, China
| | - Hongji Zhu
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, 225009, Jiangsu, China; Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou, 225009, Jiangsu, China
| | - Yingyan Chang
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, 225009, Jiangsu, China; Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou, 225009, Jiangsu, China
| | - Ge Zhao
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, 225009, Jiangsu, China; Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou, 225009, Jiangsu, China
| | - Zhiming Pan
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, 225009, Jiangsu, China; Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou, 225009, Jiangsu, China
| | - Xin'an Jiao
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, 225009, Jiangsu, China; Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou, 225009, Jiangsu, China
| | - Maozhi Hu
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, 225009, Jiangsu, China; Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou, 225009, Jiangsu, China.
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Impact of the Resistance Responses to Stress Conditions Encountered in Food and Food Processing Environments on the Virulence and Growth Fitness of Non-Typhoidal Salmonellae. Foods 2021; 10:foods10030617. [PMID: 33799446 PMCID: PMC8001757 DOI: 10.3390/foods10030617] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 02/24/2021] [Accepted: 03/10/2021] [Indexed: 01/22/2023] Open
Abstract
The success of Salmonella as a foodborne pathogen can probably be attributed to two major features: its remarkable genetic diversity and its extraordinary ability to adapt. Salmonella cells can survive in harsh environments, successfully compete for nutrients, and cause disease once inside the host. Furthermore, they are capable of rapidly reprogramming their metabolism, evolving in a short time from a stress-resistance mode to a growth or virulent mode, or even to express stress resistance and virulence factors at the same time if needed, thanks to a complex and fine-tuned regulatory network. It is nevertheless generally acknowledged that the development of stress resistance usually has a fitness cost for bacterial cells and that induction of stress resistance responses to certain agents can trigger changes in Salmonella virulence. In this review, we summarize and discuss current knowledge concerning the effects that the development of resistance responses to stress conditions encountered in food and food processing environments (including acid, osmotic and oxidative stress, starvation, modified atmospheres, detergents and disinfectants, chilling, heat, and non-thermal technologies) exerts on different aspects of the physiology of non-typhoidal Salmonellae, with special emphasis on virulence and growth fitness.
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15
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Ouali BEF, Chiou TH, Chen JW, Lin IC, Liu CC, Chiang YC, Ho TS, Wang HV. Correlation Between Pathogenic Determinants Associated with Clinically Isolated Non-Typhoidal Salmonella. Pathogens 2021; 10:pathogens10010074. [PMID: 33467782 PMCID: PMC7830680 DOI: 10.3390/pathogens10010074] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 01/01/2021] [Accepted: 01/12/2021] [Indexed: 11/23/2022] Open
Abstract
Non-typhoidal and Typhoidal Salmonella are bacterial pathogens source of worldwide and major disease burden. Virulent determinants of specific serovars belonging to non-typhoidal Salmonella have been extensively studied in different models, yet the pathogenesis of this group of bacteria and the development of clinical symptoms globally remains underexplored. Herein, we implemented microbiological and molecular procedures to investigate isolate virulence traits and molecular diversity, likely in association with disease severity. Our results show that selected clinical isolates from a tertiary referring hospital, depending on the richness of the environment and isolate serotypes, exhibited different, and sometimes controversial, virulence properties. The tested strains were susceptible to Ceftriaxone (90%) with decreasing reactivity to Trimethoprim–Sulfamethoxazole (72%), Chloramphenicol (64%), Ampicillin (48%), Gentamicin (44%), and Ciprofloxacin (2%). Disc susceptibility results partially correlated with minimum inhibitory concentration (MIC); however, special attention must be given to antimicrobial treatment, as a rise in multi-resistant isolates to Trimethoprim–Sulfamethoxazole (2/38 µg/mL), Minocycline (8 µg/mL) and Ampicillin (16 µg/mL) has been noticed, with two isolates resistant to Ceftazidime (16 µg/mL). By comparison to previous molecular epidemiology studies, the variation in the gene profiles of endemic pathogens supports the need for continuous and up-to-date microbiological and molecular reports.
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Affiliation(s)
| | - Tsyr-Huei Chiou
- Department of Life Sciences, National Cheng Kung University, Tainan 701, Taiwan; (B.E.F.O.); (T.-H.C.); (I-C.L.)
| | - Jenn-Wei Chen
- Department of Microbiology and Immunology, College of Medicine, National Cheng Kung University, Tainan 701, Taiwan;
- Center of Infectious Disease and Signaling Research, National Cheng Kung University, Tainan 701, Taiwan;
| | - I-Chu Lin
- Department of Life Sciences, National Cheng Kung University, Tainan 701, Taiwan; (B.E.F.O.); (T.-H.C.); (I-C.L.)
| | - Ching-Chuan Liu
- Center of Infectious Disease and Signaling Research, National Cheng Kung University, Tainan 701, Taiwan;
- Department of Pediatrics, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan 701, Taiwan
| | - Yu-Chung Chiang
- Department of Biological Sciences, National Sun Yat-sen University, Kaohsiung 80424, Taiwan
- Department of Biomedical Science and Environment Biology, Kaohsiung Medical University, Kaohsiung 80708, Taiwan
- Correspondence: (Y.-C.C.); (T.-S.H.); (H.-V.W.)
| | - Tzong-Shiann Ho
- Center of Infectious Disease and Signaling Research, National Cheng Kung University, Tainan 701, Taiwan;
- Department of Pediatrics, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan 701, Taiwan
- Correspondence: (Y.-C.C.); (T.-S.H.); (H.-V.W.)
| | - Hao-Ven Wang
- Department of Life Sciences, National Cheng Kung University, Tainan 701, Taiwan; (B.E.F.O.); (T.-H.C.); (I-C.L.)
- Center for Bioscience and Biotechnology, National Cheng Kung University, Tainan 701, Taiwan
- Marine Biology and Cetacean Research Center, National Cheng Kung University, Tainan 701, Taiwan
- Correspondence: (Y.-C.C.); (T.-S.H.); (H.-V.W.)
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16
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Soh SM, Jang H, Mitchell RJ. Loss of the lipopolysaccharide (LPS) inner core increases the electrocompetence of Escherichia coli. Appl Microbiol Biotechnol 2020; 104:7427-7435. [PMID: 32676713 DOI: 10.1007/s00253-020-10779-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2020] [Revised: 06/28/2020] [Accepted: 07/05/2020] [Indexed: 12/19/2022]
Abstract
Mutations that shorten the lipopolysaccharide (LPS) in Escherichia coli were found to significantly increase the number of transformants after electroporation. The loss of the LPS outer core increased the number of transformants with plasmid pAmCyan (3.3 kb) from 5.0 × 105 colony-forming units (CFU)/μg in the wild-type E. coli BW25113 to 3.3 × 107 CFU/μg in a ΔwaaG background, a 66.2-fold increase in efficiency. Truncation of the inner core improved this even further, with the ΔwaaF mutant exhibiting the best transformation efficiencies obtained, i.e., a 454.7-fold increase in the number of colonies over the wild-type strain. Similar results were obtained when a larger plasmid (pDA1; 11.3 kb) was used, with the ΔwaaF mutant once more giving the best transformation rates, i.e., a 73.7-fold increase. Subsequent tests proved that the enhanced transformabilities of these mutants were not due to a better survival or their surface charge properties, nor from preferential binding of these strains to the plasmid. Using N-phenyl-1-naphthylamine (NPN), we confirmed that the outer membranes of these mutant strains were more permeable. We also found that they leaked more ATP (3.4- and 2.0-fold higher for the ΔwaaF and ΔwaaG mutants, respectively, than wild-type E. coli BW25113), suggesting that the inner membrane stability is also reduced, helping to explain how the DNA enters these cells more easily. KEY POINTS: • LPS inner core gene knockouts increase the electrocompetence of E. coli. • No significant difference in survival, surface charge, or DNA binding was evident. • The LPS inner core mutants, however, exhibited higher outer membrane permeability. • Their inner membranes were also leaky, based on supernatant ATP concentrations.
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Affiliation(s)
- Sandrine M Soh
- School of Life Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, South Korea
| | - Hyochan Jang
- School of Life Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, South Korea
| | - Robert J Mitchell
- School of Life Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, South Korea.
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17
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Methylation of Salmonella Typhimurium flagella promotes bacterial adhesion and host cell invasion. Nat Commun 2020; 11:2013. [PMID: 32332720 PMCID: PMC7181671 DOI: 10.1038/s41467-020-15738-3] [Citation(s) in RCA: 57] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Accepted: 03/13/2020] [Indexed: 11/09/2022] Open
Abstract
The long external filament of bacterial flagella is composed of several thousand copies of a single protein, flagellin. Here, we explore the role played by lysine methylation of flagellin in Salmonella, which requires the methylase FliB. We show that both flagellins of Salmonella enterica serovar Typhimurium, FliC and FljB, are methylated at surface-exposed lysine residues by FliB. A Salmonella Typhimurium mutant deficient in flagellin methylation is outcompeted for gut colonization in a gastroenteritis mouse model, and methylation of flagellin promotes bacterial invasion of epithelial cells in vitro. Lysine methylation increases the surface hydrophobicity of flagellin, and enhances flagella-dependent adhesion of Salmonella to phosphatidylcholine vesicles and epithelial cells. Therefore, posttranslational methylation of flagellin facilitates adhesion of Salmonella Typhimurium to hydrophobic host cell surfaces, and contributes to efficient gut colonization and host infection. Flagellin proteins of Salmonella flagella are methylated. Here, the authors show that flagellin methylation facilitates adhesion of Salmonella to hydrophobic host-cell surfaces, and contributes to efficient gut colonization and host infection.
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18
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Zhang D, Gan RY, Zhang JR, Farha AK, Li HB, Zhu F, Wang XH, Corke H. Antivirulence properties and related mechanisms of spice essential oils: A comprehensive review. Compr Rev Food Sci Food Saf 2020; 19:1018-1055. [PMID: 33331691 DOI: 10.1111/1541-4337.12549] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Revised: 01/09/2020] [Accepted: 01/30/2020] [Indexed: 12/19/2022]
Abstract
In recent decades, reduced antimicrobial effectiveness, increased bacterial infection, and newly emerged microbial resistance have become global public issues, leading to an urgent need to find effective strategies to counteract these problems. Strategies targeting bacterial virulence factors rather than bacterial survival have attracted increasing interest, since the modulation of virulence factors may prevent the development of drug resistance in bacteria. Spices are promising natural sources of antivirulence compounds owing to their wide availability, diverse antivirulence phytochemical constituents, and generally favorable safety profiles. Essential oils are the predominant and most important antivirulence components of spices. This review addresses the recent efforts of using spice essential oils to inhibit main bacterial virulence traits, including the quorum sensing system, biofilm formation, motility, and toxin production, with an intensive discussion of related mechanisms. We hope that this review can provide a better understanding of the antivirulence properties of spice essential oils, which have the potential to be used as antibiotic alternatives by targeting bacterial virulence.
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Affiliation(s)
- Dan Zhang
- Department of Food Science & Technology, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
| | - Ren-You Gan
- Department of Food Science & Technology, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China.,Research Center for Plants and Human Health, Institute of Urban Agriculture, Chinese Academy of Agricultural Sciences, Chengdu, China
| | - Jia-Rong Zhang
- Department of Food Science & Technology, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
| | - Arakkaveettil Kabeer Farha
- Department of Food Science & Technology, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
| | - Hua-Bin Li
- Guangdong Provincial Key Laboratory of Food, Nutrition and Health, Department of Nutrition, School of Public Health, Sun Yat-Sen University, Guangzhou, China
| | - Fan Zhu
- School of Chemical Sciences, University of Auckland, Auckland, New Zealand
| | - Xiao-Hong Wang
- College of Food Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Harold Corke
- Department of Food Science & Technology, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
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Raman V, Van Dessel N, O'Connor OM, Forbes NS. The motility regulator flhDC drives intracellular accumulation and tumor colonization of Salmonella. J Immunother Cancer 2019; 7:44. [PMID: 30755273 PMCID: PMC6373116 DOI: 10.1186/s40425-018-0490-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Accepted: 12/20/2018] [Indexed: 12/11/2022] Open
Abstract
Background Salmonella have potential as anticancer therapeutic because of their innate tumor specificity. In clinical studies, this specificity has been hampered by heterogeneous responses. Understanding the mechanisms that control tumor colonization would enable the design of more robust therapeutic strains. Two mechanisms that could affect tumor colonization are intracellular accumulation and intratumoral motility. Both of these mechanisms have elements that are controlled by the master motility regulator flhDC. We hypothesized that 1) overexpressing flhDC in Salmonella increases intracellular bacterial accumulation in tumor cell masses, and 2) intracellular accumulation of Salmonella drives tumor colonization in vitro. Methods To test these hypotheses, we transformed Salmonella with genetic circuits that induce flhDC and express green fluorescent protein after intracellular invasion. The genetically modified Salmonella was perfused into an in vitro tumor-on-a-chip device. Time-lapse fluorescence microscopy was used to quantify intracellular and colonization dynamics within tumor masses. A mathematical model was used to determine how these mechanisms are related to each other. Results Overexpression of flhDC increased intracellular accumulation and tumor colonization 2.5 and 5 times more than control Salmonella, respectively (P < 0.05). Non-motile Salmonella accumulated in cancer cells 26 times less than controls (P < 0.001). Minimally invasive, ΔsipB, Salmonella colonized tumor masses 2.5 times less than controls (P < 0.05). When flhDC was selectively induced after penetration into tumor masses, Salmonella both accumulated intracellularly and colonized tumor masses 2 times more than controls (P < 0.05). Mathematical modeling of tumor colonization dynamics demonstrated that intracellular accumulation increased retention of Salmonella in tumors by effectively causing the bacteria to bind to cancer cells and preventing leakage out of the tumors. These results demonstrated that increasing intracellular bacterial density increased overall tumor colonization and that flhDC could be used to control both. Conclusions This study demonstrates a mechanistic link between motility, intracellular accumulation and tumor colonization. Based on our results, we envision that therapeutic strains of Salmonella could use inducible flhDC to drive tumor colonization. More intratumoral bacteria would enable delivery of higher therapeutic payloads into tumors and would improve treatment efficacy. Electronic supplementary material The online version of this article (10.1186/s40425-018-0490-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Vishnu Raman
- Department of Chemical Engineering, University of Massachusetts, 159 Goessmann Laboratory, 686 North Pleasant St, Amherst, MA, 01003, USA
| | - Nele Van Dessel
- Department of Chemical Engineering, University of Massachusetts, 159 Goessmann Laboratory, 686 North Pleasant St, Amherst, MA, 01003, USA
| | - Owen M O'Connor
- Department of Chemical Engineering, University of Massachusetts, 159 Goessmann Laboratory, 686 North Pleasant St, Amherst, MA, 01003, USA
| | - Neil S Forbes
- Department of Chemical Engineering, University of Massachusetts, 159 Goessmann Laboratory, 686 North Pleasant St, Amherst, MA, 01003, USA.
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20
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Jacek P, Szustak M, Kubiak K, Gendaszewska-Darmach E, Ludwicka K, Bielecki S. Scaffolds for Chondrogenic Cells Cultivation Prepared from Bacterial Cellulose with Relaxed Fibers Structure Induced Genetically. NANOMATERIALS (BASEL, SWITZERLAND) 2018; 8:E1066. [PMID: 30563030 PMCID: PMC6315621 DOI: 10.3390/nano8121066] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Revised: 12/06/2018] [Accepted: 12/14/2018] [Indexed: 11/16/2022]
Abstract
Development of three-dimensional scaffolds mimicking in vivo cells' environment is an ongoing challenge for tissue engineering. Bacterial nano-cellulose (BNC) is a well-known biocompatible material with enormous water-holding capacity. However, a tight spatial organization of cellulose fibers limits cell ingrowth and restricts practical use of BNC-based scaffolds. The aim of this study was to address this issue avoiding any chemical treatment of natural nanomaterial. Genetic modifications of Komagataeibacter hansenii ATCC 23769 strain along with structural and mechanical properties characterization of obtained BNC membranes were conducted. Furthermore, the membranes were evaluated as scaffolds in in vitro assays to verify cells viability and glycosaminoglycan synthesis by chondrogenic ATDC5 cells line as well as RBL-2H3 mast cells degranulation. K. hansenii mutants with increased cell lengths and motility were shown to produce BNC membranes with increased pore sizes. Novel, BNC membranes with relaxed fiber structure revealed superior properties as scaffolds when compared to membranes produced by a wild-type strain. Obtained results confirm that a genetic modification of productive bacterial strain is a plausible way of adjustment of bacterial cellulose properties for tissue engineering applications without the employment of any chemical modifications.
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Affiliation(s)
- Paulina Jacek
- Institute of Technical Biochemistry, Lodz University of Technology, 4/10 Stefanowskiego Str., 90-924 Łódź, Poland.
| | - Marcin Szustak
- Institute of Technical Biochemistry, Lodz University of Technology, 4/10 Stefanowskiego Str., 90-924 Łódź, Poland.
| | - Katarzyna Kubiak
- Institute of Technical Biochemistry, Lodz University of Technology, 4/10 Stefanowskiego Str., 90-924 Łódź, Poland.
| | - Edyta Gendaszewska-Darmach
- Institute of Technical Biochemistry, Lodz University of Technology, 4/10 Stefanowskiego Str., 90-924 Łódź, Poland.
| | - Karolina Ludwicka
- Institute of Technical Biochemistry, Lodz University of Technology, 4/10 Stefanowskiego Str., 90-924 Łódź, Poland.
| | - Stanisław Bielecki
- Institute of Technical Biochemistry, Lodz University of Technology, 4/10 Stefanowskiego Str., 90-924 Łódź, Poland.
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El Sayed F, Sapriel G, Fawal N, Gruber A, Bauer T, Heym B, Dupont C, Garchon HJ, Gaillard JL, Rottman M, Le Hello S. In-Host Adaptation of Salmonella enterica Serotype Dublin during Prosthetic Hip Joint Infection. Emerg Infect Dis 2018. [DOI: 10.3201/eid2312.180214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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22
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El Sayed F, Sapriel G, Fawal N, Gruber A, Bauer T, Heym B, Dupont C, Garchon HJ, Gaillard JL, Rottman M, Le Hello S. In-Host Adaptation of Salmonella enterica Serotype Dublin during Prosthetic Hip Joint Infection. Emerg Infect Dis 2018; 24:2360-2363. [PMID: 30457550 PMCID: PMC6256398 DOI: 10.3201/eid2412.180214] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Genome degradation has been central to the adaptation of Salmonella enterica serotypes to their hosts throughout evolution. We witnessed the patho-adaptation of a strain of Salmonella Dublin (a cattle-adapted serotype) to a human host during the course of a recurrent prosthetic hip joint infection evolving over several years.
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Bartling P, Vollmers J, Petersen J. The first world swimming championships of roseobacters—Phylogenomic insights into an exceptional motility phenotype. Syst Appl Microbiol 2018; 41:544-554. [DOI: 10.1016/j.syapm.2018.08.012] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Revised: 08/13/2018] [Accepted: 08/25/2018] [Indexed: 11/29/2022]
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Jiao Y, Xia Z, Zhou X, Guo Y, Guo R, Kang X, Wu K, Sun J, Xu X, Jiao X, Pan Z, Liu X. Signature-tagged mutagenesis screening revealed the role of lipopolysaccharide biosynthesis gene rfbH in smooth-to-rough transition in Salmonella Enteritidis. Microbiol Res 2018; 212-213:75-79. [PMID: 29853170 DOI: 10.1016/j.micres.2018.05.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Revised: 04/27/2018] [Accepted: 05/02/2018] [Indexed: 11/15/2022]
Abstract
Salmonella enterica serovar Enteritidis (S. Enteritidis, SE) is a major cause of foodborne diseases for humans. The completeness of the O-chain antigen of Lipopolysaccharide (LPS) determines whether a S. Enteritidis strain is smooth or rough. However, genes that are involved in the synthesis of LPS and rough-smooth variation are not completely understood. In this study, we used monoclonal antibody against O-antigens (O9 mAb) to identify novel factors that are involved in LPS synthesis and rough variation in S. Enteritidis by using signature-tagged mutagenesis (STM) technique. Our results showed that transposon insertion in the gene rfbH led to different LPS phenotype, auto-aggregation characteristic, motility and resistance to environmental stress compared with SE wild-type strain C50041. In addition, sera tests showed that rfbH mutant does not elicit specific antibodies against O-antigens in vaccinated animals. Taken together, the S. Enteritidis rfbH gene is implicated in LPS biosynthesis, rough variation, sera distinguishable reaction, motility and stress resistance. The rfbH mutant strain could be potentially used as a distinguishable vaccine or a live vector to deliver drugs and antibodies in vivo.
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Affiliation(s)
- Yang Jiao
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou, Jiangsu, 225009, China; Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, Jiangsu, 225009, China; Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, MOA, Yangzhou University, Yangzhou, Jiangsu, 225009, China; Joint International Research Laboratory of Agriculture and Agri-product Safety of the Ministry of Education, Yangzhou University, Yangzhou, Jiangsu, 225009, China
| | - Zemiao Xia
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou, Jiangsu, 225009, China; Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, Jiangsu, 225009, China; Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, MOA, Yangzhou University, Yangzhou, Jiangsu, 225009, China; Joint International Research Laboratory of Agriculture and Agri-product Safety of the Ministry of Education, Yangzhou University, Yangzhou, Jiangsu, 225009, China
| | - Xiaohui Zhou
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou, Jiangsu, 225009, China; Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, Jiangsu, 225009, China; Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, MOA, Yangzhou University, Yangzhou, Jiangsu, 225009, China; Joint International Research Laboratory of Agriculture and Agri-product Safety of the Ministry of Education, Yangzhou University, Yangzhou, Jiangsu, 225009, China; Pathobiology and Veterinary Science, College of Agriculture, Health and Natural Resources, University of Connecticut, 61 North Eagleville Road, Unit-3089, Mansfield, CT, USA
| | - Yaxin Guo
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou, Jiangsu, 225009, China; Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, Jiangsu, 225009, China; Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, MOA, Yangzhou University, Yangzhou, Jiangsu, 225009, China; Joint International Research Laboratory of Agriculture and Agri-product Safety of the Ministry of Education, Yangzhou University, Yangzhou, Jiangsu, 225009, China
| | - Rongxian Guo
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou, Jiangsu, 225009, China; Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, Jiangsu, 225009, China; Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, MOA, Yangzhou University, Yangzhou, Jiangsu, 225009, China; Joint International Research Laboratory of Agriculture and Agri-product Safety of the Ministry of Education, Yangzhou University, Yangzhou, Jiangsu, 225009, China
| | - Xilong Kang
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou, Jiangsu, 225009, China; Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, Jiangsu, 225009, China; Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, MOA, Yangzhou University, Yangzhou, Jiangsu, 225009, China; Joint International Research Laboratory of Agriculture and Agri-product Safety of the Ministry of Education, Yangzhou University, Yangzhou, Jiangsu, 225009, China
| | - Kaiyue Wu
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou, Jiangsu, 225009, China; Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, Jiangsu, 225009, China; Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, MOA, Yangzhou University, Yangzhou, Jiangsu, 225009, China; Joint International Research Laboratory of Agriculture and Agri-product Safety of the Ministry of Education, Yangzhou University, Yangzhou, Jiangsu, 225009, China
| | - Jun Sun
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, Jiangsu, 225009, China; Division of Gastroenterology and Hepatology, College of Medicine, University of Illinois at Chicago, Chicago, IL, 60612, USA
| | - Xiulong Xu
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou, Jiangsu, 225009, China; Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, Jiangsu, 225009, China; Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, MOA, Yangzhou University, Yangzhou, Jiangsu, 225009, China; Joint International Research Laboratory of Agriculture and Agri-product Safety of the Ministry of Education, Yangzhou University, Yangzhou, Jiangsu, 225009, China
| | - Xinan Jiao
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou, Jiangsu, 225009, China; Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, Jiangsu, 225009, China; Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, MOA, Yangzhou University, Yangzhou, Jiangsu, 225009, China; Joint International Research Laboratory of Agriculture and Agri-product Safety of the Ministry of Education, Yangzhou University, Yangzhou, Jiangsu, 225009, China
| | - Zhiming Pan
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou, Jiangsu, 225009, China; Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, Jiangsu, 225009, China; Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, MOA, Yangzhou University, Yangzhou, Jiangsu, 225009, China; Joint International Research Laboratory of Agriculture and Agri-product Safety of the Ministry of Education, Yangzhou University, Yangzhou, Jiangsu, 225009, China.
| | - Xiufan Liu
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou, Jiangsu, 225009, China; Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, Jiangsu, 225009, China; Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, MOA, Yangzhou University, Yangzhou, Jiangsu, 225009, China; Joint International Research Laboratory of Agriculture and Agri-product Safety of the Ministry of Education, Yangzhou University, Yangzhou, Jiangsu, 225009, China.
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25
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Regulation of Flagellum Biosynthesis in Response to Cell Envelope Stress in Salmonella enterica Serovar Typhimurium. mBio 2018; 9:mBio.00736-17. [PMID: 29717015 PMCID: PMC5930307 DOI: 10.1128/mbio.00736-17] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Flagellum-driven motility of Salmonella enterica serovar Typhimurium facilitates host colonization. However, the large extracellular flagellum is also a prime target for the immune system. As consequence, expression of flagella is bistable within a population of Salmonella, resulting in flagellated and nonflagellated subpopulations. This allows the bacteria to maximize fitness in hostile environments. The degenerate EAL domain protein RflP (formerly YdiV) is responsible for the bistable expression of flagella by directing the flagellar master regulatory complex FlhD4C2 with respect to proteolytic degradation. Information concerning the environmental cues controlling expression of rflP and thus about the bistable flagellar biosynthesis remains ambiguous. Here, we demonstrated that RflP responds to cell envelope stress and alterations of outer membrane integrity. Lipopolysaccharide (LPS) truncation mutants of Salmonella Typhimurium exhibited increasing motility defects due to downregulation of flagellar gene expression. Transposon mutagenesis and genetic profiling revealed that σ24 (RpoE) and Rcs phosphorelay-dependent cell envelope stress response systems sense modifications of the lipopolysaccaride, low pH, and activity of the complement system. This subsequently results in activation of RflP expression and degradation of FlhD4C2 via ClpXP. We speculate that the presence of diverse hostile environments inside the host might result in cell envelope damage and would thus trigger the repression of resource-costly and immunogenic flagellum biosynthesis via activation of the cell envelope stress response. Pathogenic bacteria such as Salmonella Typhimurium sense and adapt to a multitude of changing and stressful environments during host infection. At the initial stage of gastrointestinal colonization, Salmonella uses flagellum-mediated motility to reach preferred sites of infection. However, the flagellum also constitutes a prime target for the host’s immune response. Accordingly, the pathogen needs to determine the spatiotemporal stage of infection and control flagellar biosynthesis in a robust manner. We found that Salmonella uses signals from cell envelope stress-sensing systems to turn off production of flagella. We speculate that downregulation of flagellum synthesis after cell envelope damage in hostile environments aids survival of Salmonella during late stages of infection and provides a means to escape recognition by the immune system.
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26
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Octavia S, Ang MLT, La MV, Zulaina S, Saat ZAAS, Tien WS, Han HK, Ooi PL, Cui L, Lin RTP. Retrospective genome-wide comparisons of Salmonella enterica serovar Enteritidis from suspected outbreaks in Singapore. INFECTION GENETICS AND EVOLUTION 2018; 61:229-233. [PMID: 29625239 DOI: 10.1016/j.meegid.2018.04.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Revised: 03/13/2018] [Accepted: 04/02/2018] [Indexed: 11/25/2022]
Abstract
The number of salmonellosis cases in Singapore has increased over the years. Salmonella enterica serovar Enteritidis has always been the most predominant serovar in the last five years. The National Public Health Laboratory assisted outbreak investigations by performing multilocus variable number tandem repeat analysis (MLVA) on isolates that were collected at the time of the investigations. Isolates were defined as belonging to a particular cluster if they had identical MLVA patterns. Whilst MLVA has been instrumental in outbreak investigations, it may not be useful when outbreaks are caused by an endemic MLVA type. In this study, we analysed 67 isolates from 12 suspected outbreaks with known epidemiological links to explore the use of next-generation sequencing (NGS) for defining outbreaks. We found that NGS can confidently group isolates into their respective outbreaks. The isolates from each suspected outbreak were closely related and differed by a maximum of 3 single nucleotide polymorphisms (SNPs). They were also clearly separated from isolates that belonged to different suspected outbreaks. This study provides an important insight and further evidence on the value of NGS for routine surveillance and outbreak detection of S. Enteritidis.
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Affiliation(s)
- Sophie Octavia
- National Public Health Laboratory, Ministry of Health, Singapore.
| | - Michelle L T Ang
- National Public Health Laboratory, Ministry of Health, Singapore
| | - My Van La
- National Public Health Laboratory, Ministry of Health, Singapore
| | - Siti Zulaina
- National Public Health Laboratory, Ministry of Health, Singapore
| | - Zul Azri As Saad Saat
- Communicable Diseases Division (Surveillance & Response), Ministry of Health, Singapore
| | - Wee Siong Tien
- Communicable Diseases Division (Surveillance & Response), Ministry of Health, Singapore
| | - Hwi Kwang Han
- Communicable Diseases Division (Surveillance & Response), Ministry of Health, Singapore
| | - Peng Lim Ooi
- Communicable Diseases Division (Surveillance & Response), Ministry of Health, Singapore
| | - Lin Cui
- National Public Health Laboratory, Ministry of Health, Singapore
| | - Raymond T P Lin
- National Public Health Laboratory, Ministry of Health, Singapore; Department of Laboratory Medicine, National University Hospital, Singapore
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27
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Novel genes associated with enhanced motility of Escherichia coli ST131. PLoS One 2017; 12:e0176290. [PMID: 28489862 PMCID: PMC5425062 DOI: 10.1371/journal.pone.0176290] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Accepted: 04/07/2017] [Indexed: 12/20/2022] Open
Abstract
Uropathogenic Escherichia coli (UPEC) is the cause of ~75% of all urinary tract infections (UTIs) and is increasingly associated with multidrug resistance. This includes UPEC strains from the recently emerged and globally disseminated sequence type 131 (ST131), which is now the dominant fluoroquinolone-resistant UPEC clone worldwide. Most ST131 strains are motile and produce H4-type flagella. Here, we applied a combination of saturated Tn5 mutagenesis and transposon directed insertion site sequencing (TraDIS) as a high throughput genetic screen and identified 30 genes associated with enhanced motility of the reference ST131 strain EC958. This included 12 genes that repress motility of E. coli K-12, four of which (lrhA, ihfA, ydiV, lrp) were confirmed in EC958. Other genes represented novel factors that impact motility, and we focused our investigation on characterisation of the mprA, hemK and yjeA genes. Mutation of each of these genes in EC958 led to increased transcription of flagellar genes (flhD and fliC), increased expression of the FliC flagellin, enhanced flagella synthesis and a hyper-motile phenotype. Complementation restored all of these properties to wild-type level. We also identified Tn5 insertions in several intergenic regions (IGRs) on the EC958 chromosome that were associated with enhanced motility; this included flhDC and EC958_1546. In both of these cases, the Tn5 insertions were associated with increased transcription of the downstream gene(s), which resulted in enhanced motility. The EC958_1546 gene encodes a phage protein with similarity to esterase/deacetylase enzymes involved in the hydrolysis of sialic acid derivatives found in human mucus. We showed that over-expression of EC958_1546 led to enhanced motility of EC958 as well as the UPEC strains CFT073 and UTI89, demonstrating its activity affects the motility of different UPEC strains. Overall, this study has identified and characterised a number of novel factors associated with enhanced UPEC motility.
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28
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Jiao Y, Guo R, Tang P, Kang X, Yin J, Wu K, Geng S, Li Q, Sun J, Xu X, Zhou X, Gan J, Jiao X, Liu X, Pan Z. Signature-tagged mutagenesis screening revealed a novel smooth-to-rough transition determinant of Salmonella enterica serovar Enteritidis. BMC Microbiol 2017; 17:48. [PMID: 28253852 PMCID: PMC5335844 DOI: 10.1186/s12866-017-0951-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2016] [Accepted: 02/08/2017] [Indexed: 11/25/2022] Open
Abstract
Background Salmonella enterica serovar Enteritidis (S. Enteritidis) has emerged as one of the most important food-borne pathogens for humans. Lipopolysaccharide (LPS), as a component of the outer membrane, is responsible for the virulence and smooth-to-rough transition in S. Enteritidis. In this study, we screened S. Enteritidis signature-tagged transposon mutant library using monoclonal antibody against somatic O9 antigen (O9 MAb) and O9 factor rabbit antiserum to identify novel genes that are involved in smooth-to-rough transition. Results A total of 480 mutants were screened and one mutant with transposon insertion in rfbG gene had smooth-to-rough transition phenotype. In order to verify the role of rfbG gene, an rfbG insertion or deletion mutant was constructed using λ-Red recombination system. Phenotypic and biological analysis revealed that rfbG insertion or deletion mutants were similar to the wild-type strain in growth rate and biochemical properties, but the swimming motility was reduced. SE Slide Agglutination test and ELISA test showed that rfbG mutants do not stimulate animals to produce agglutinating antibody. In addition, the half-lethal dose (LD50) of the rfbG deletion mutant strain was 106.6 -fold higher than that of the parent strain in a mouse model when injected intraperitoneally. Conclusions These data indicate that the rfbG gene is involved in smooth-to-rough transition, swimming motility and virulence of S. Enteritidis. Furthermore, somatic O-antigen antibody-based approach to screen signature-tagged transposon mutants is feasible to clarify LPS biosynthesis and to find suitable markers in DIVA-vaccine research.
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Affiliation(s)
- Yang Jiao
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, 48 East Wenhui Road, Yangzhou, Jiangsu, 225009, China.,Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, Jiangsu, 225009, China
| | - Rongxian Guo
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, 48 East Wenhui Road, Yangzhou, Jiangsu, 225009, China.,Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, Jiangsu, 225009, China
| | - Peipei Tang
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, 48 East Wenhui Road, Yangzhou, Jiangsu, 225009, China.,Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, Jiangsu, 225009, China
| | - Xilong Kang
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, 48 East Wenhui Road, Yangzhou, Jiangsu, 225009, China.,Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, Jiangsu, 225009, China
| | - Junlei Yin
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, 48 East Wenhui Road, Yangzhou, Jiangsu, 225009, China.,Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, Jiangsu, 225009, China
| | - Kaiyue Wu
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, 48 East Wenhui Road, Yangzhou, Jiangsu, 225009, China.,Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, Jiangsu, 225009, China
| | - Shizhong Geng
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, 48 East Wenhui Road, Yangzhou, Jiangsu, 225009, China.,Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, Jiangsu, 225009, China
| | - Qiuchun Li
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, 48 East Wenhui Road, Yangzhou, Jiangsu, 225009, China.,Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, Jiangsu, 225009, China
| | - Jun Sun
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, Jiangsu, 225009, China.,Division of Gastroenterology and Hepatology Department of Medicine, University of Illinois at Chicago, 840 S Wood Street, Room 704 CSB, 60612, Chicago, IL, USA
| | - Xiulong Xu
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, Jiangsu, 225009, China
| | - Xiaohui Zhou
- Pathobiology and Veterinary Science, College of Agriculture, Health and Natural Resources, University of Connecticut, 61 North Eagleville Road, Unit-3089, Mansfield, CT, USA
| | - Junji Gan
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, 48 East Wenhui Road, Yangzhou, Jiangsu, 225009, China.,Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, Jiangsu, 225009, China
| | - Xinan Jiao
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, 48 East Wenhui Road, Yangzhou, Jiangsu, 225009, China.,Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, Jiangsu, 225009, China
| | - Xiufan Liu
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, 48 East Wenhui Road, Yangzhou, Jiangsu, 225009, China. .,Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, Jiangsu, 225009, China.
| | - Zhiming Pan
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, 48 East Wenhui Road, Yangzhou, Jiangsu, 225009, China. .,Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, Jiangsu, 225009, China.
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29
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Beyond Antimicrobial Resistance: Evidence for a Distinct Role of the AcrD Efflux Pump in Salmonella Biology. mBio 2016; 7:mBio.01916-16. [PMID: 27879336 PMCID: PMC5120143 DOI: 10.1128/mbio.01916-16] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
For over 20 years, bacterial multidrug resistance (MDR) efflux pumps have been studied because of their impact on resistance to antimicrobials. However, critical questions remain, including why produce efflux pumps under non-antimicrobial treatment conditions, and why have multiple pumps if their only purpose is antimicrobial efflux? Salmonella spp. possess five efflux pump families, including the resistance-nodulation-division (RND) efflux pumps. Notably, the RND efflux pump AcrD has a unique substrate profile, distinct from other Salmonella efflux pumps. Here we show that inactivation of acrD results in a profoundly altered transcriptome and modulation of pathways integral to Salmonella biology. The most significant transcriptome changes were central metabolism related, with additional changes observed in pathogenicity, environmental sensing, and stress response pathway expression. The extent of tricarboxylic acid cycle and fumarate metabolism expression changes led us to hypothesize that acrD inactivation may result in motility defects due to perturbation of metabolite concentrations, such as fumarate, for which a role in motility has been established. Despite minimal detectable changes in flagellar gene expression, we found that an acrD mutant Salmonella enterica serovar Typhimurium isolate was significantly impaired for swarming motility, which was restored by addition of fumarate. The acrD mutant outcompeted the wild type in fitness experiments. The results of these diverse experiments provide strong evidence that the AcrD efflux pump is not simply a redundant system providing response resilience, but also has distinct physiological functions. Together, these data indicate that the AcrD efflux pump has a significant and previously underappreciated impact on bacterial biology, despite only minor perturbations of antibiotic resistance profiles. Efflux pumps in Gram-negative bacteria are studied because of their important contributions to antimicrobial resistance. However, the role of these pumps in bacterial biology has remained surprisingly elusive. Here, we provide evidence that loss of the AcrD efflux pump significantly impacts the physiology of Salmonella enterica serovar Typhimurium. Inactivation of acrD led to changes in the expression of 403 genes involved in fundamental processes, including basic metabolism, virulence, and stress responses. Pathways such as these allow Salmonella to grow, survive in the environment, and cause disease. Indeed, our data show that the acrD mutant is more fit than wild-type Salmonella under standard lab conditions. We hypothesized that inactivation of acrD would alter levels of bacterial metabolites, impacting traits such as swarming motility. We demonstrated this by exogenous addition of the metabolite fumarate, which partially restored the acrD mutant’s swarming defect. This work extends our understanding of the role of bacterial efflux pumps.
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30
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aroA-Deficient Salmonella enterica Serovar Typhimurium Is More Than a Metabolically Attenuated Mutant. mBio 2016; 7:mBio.01220-16. [PMID: 27601574 PMCID: PMC5013297 DOI: 10.1128/mbio.01220-16] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Recombinant attenuated Salmonella enterica serovar Typhimurium strains are believed to act as powerful live vaccine carriers that are able to elicit protection against various pathogens. Auxotrophic mutations, such as a deletion of aroA, are commonly introduced into such bacteria for attenuation without incapacitating immunostimulation. In this study, we describe the surprising finding that deletion of aroA dramatically increased the virulence of attenuated Salmonella in mouse models. Mutant bacteria lacking aroA elicited increased levels of the proinflammatory cytokine tumor necrosis factor alpha (TNF-α) after systemic application. A detailed genetic and phenotypic characterization in combination with transcriptomic and metabolic profiling demonstrated that ΔaroA mutants display pleiotropic alterations in cellular physiology and lipid and amino acid metabolism, as well as increased sensitivity to penicillin, complement, and phagocytic uptake. In concert with other immunomodulating mutations, deletion of aroA affected flagellin phase variation and gene expression of the virulence-associated genes arnT and ansB. Finally, ΔaroA strains displayed significantly improved tumor therapeutic activity. These results highlight the importance of a functional shikimate pathway to control homeostatic bacterial physiology. They further highlight the great potential of ΔaroA-attenuated Salmonella for the development of vaccines and cancer therapies with important implications for host-pathogen interactions and translational medicine. Recombinant attenuated bacterial vector systems based on genetically engineered Salmonella have been developed as highly potent vaccines. Due to the pathogenic properties of Salmonella, efficient attenuation is required for clinical applications. Since the hallmark study by Hoiseth and Stocker in 1981 (S. K. Hoiseth and B. A. D. Stocker, Nature 291:238–239, 1981, http://dx.doi.org/10.1038/291238a0), the auxotrophic ΔaroA mutation has been generally considered safe and universally used to attenuate bacterial strains. Here, we are presenting the remarkable finding that a deletion of aroA leads to pronounced alterations of gene expression, metabolism, and cellular physiology, which resulted in increased immunogenicity, virulence, and adjuvant potential of Salmonella. These results suggest that the enhanced immunogenicity of aroA-deficient Salmonella strains might be advantageous for optimizing bacterial vaccine carriers and immunotherapy. Accordingly, we demonstrate a superior performance of ΔaroA Salmonella in bacterium-mediated tumor therapy. In addition, the present study highlights the importance of a functional shikimate pathway to sustain bacterial physiology and metabolism.
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31
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De Maayer P, Cowan DA. Flashy flagella: flagellin modification is relatively common and highly versatile among the Enterobacteriaceae. BMC Genomics 2016; 17:377. [PMID: 27206480 PMCID: PMC4875605 DOI: 10.1186/s12864-016-2735-x] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Accepted: 05/12/2016] [Indexed: 11/16/2022] Open
Abstract
Background Post-translational glycosylation of the flagellin protein is relatively common among Gram-negative bacteria, and has been linked to several phenotypes, including flagellar biosynthesis and motility, biofilm formation, host immune evasion and manipulation and virulence. However to date, despite extensive physiological and genetic characterization, it has never been reported for the peritrichously flagellate Enterobacteriaceae. Results Using comparative genomic approaches we analyzed 2,000 representative genomes of Enterobacteriaceae, and show that flagellin glycosylation islands are relatively common and extremely versatile among members of this family. Differences in the G + C content of the FGIs and the rest of the genome and the presence of mobile genetic elements provide evidence of horizontal gene transfer occurring within the FGI loci. These loci therefore encode highly variable flagellin glycan structures, with distinct sugar backbones, heavily substituted with formyl, methyl, acetyl, lipoyl and amino groups. Additionally, an N-lysine methylase, FliB, previously identified only in the enterobacterial pathogen Salmonella enterica, is relatively common among several distinct taxa within the family. These flagellin methylase island loci (FMIs), in contrast to the FGI loci, appear to be stably maintained within these diverse lineages. Conclusions The prevalence and versatility of flagellin modification loci, both glycosylation and methylation loci, suggests they play important biological roles among the Enterobacteriaceae. Electronic supplementary material The online version of this article (doi:10.1186/s12864-016-2735-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Pieter De Maayer
- Centre for Microbial Ecology and Genomics, University of Pretoria, 0002, Pretoria, South Africa. .,Department of Microbiology, University of Pretoria, 0002, Pretoria, South Africa.
| | - Don A Cowan
- Centre for Microbial Ecology and Genomics, University of Pretoria, 0002, Pretoria, South Africa
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