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Su MSW, Cheng YL, Lin YS, Wu JJ. Interplay between group A Streptococcus and host innate immune responses. Microbiol Mol Biol Rev 2024; 88:e0005222. [PMID: 38451081 DOI: 10.1128/mmbr.00052-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/08/2024] Open
Abstract
SUMMARYGroup A Streptococcus (GAS), also known as Streptococcus pyogenes, is a clinically well-adapted human pathogen that harbors rich virulence determinants contributing to a broad spectrum of diseases. GAS is capable of invading epithelial, endothelial, and professional phagocytic cells while evading host innate immune responses, including phagocytosis, selective autophagy, light chain 3-associated phagocytosis, and inflammation. However, without a more complete understanding of the different ways invasive GAS infections develop, it is difficult to appreciate how GAS survives and multiplies in host cells that have interactive immune networks. This review article attempts to provide an overview of the behaviors and mechanisms that allow pathogenic GAS to invade cells, along with the strategies that host cells practice to constrain GAS infection. We highlight the counteractions taken by GAS to apply virulence factors such as streptolysin O, nicotinamide-adenine dinucleotidase, and streptococcal pyrogenic exotoxin B as a hindrance to host innate immune responses.
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Affiliation(s)
- Marcia Shu-Wei Su
- Department of Medical Laboratory Science and Biotechnology, College of Medical and Health Sciences, Asia University, Taichung, Taiwan
- Department of Biotechnology and Laboratory Science in Medicine, College of Biomedical Science and Engineering, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Yi-Lin Cheng
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan
- Department of Medical Laboratory Science and Biotechnology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
- Department of Microbiology and Immunology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
- Center of Infectious Disease and Signaling Research, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Yee-Shin Lin
- Department of Microbiology and Immunology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
- Center of Infectious Disease and Signaling Research, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Jiunn-Jong Wu
- Department of Medical Laboratory Science and Biotechnology, College of Medical and Health Sciences, Asia University, Taichung, Taiwan
- Department of Biotechnology and Laboratory Science in Medicine, College of Biomedical Science and Engineering, National Yang Ming Chiao Tung University, Taipei, Taiwan
- Department of Medical Research, China Medical University Hospital, China Medical University, Taichung, Taiwan
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Gong JJ, Huang IH, Su MSW, Xie SX, Liu WY, Huang CR, Hung YP, Wu SR, Tsai PJ, Ko WC, Chen JW. Phage transcriptional regulator X (PtrX)-mediated augmentation of toxin production and virulence in Clostridioides difficile strain R20291. Microbiol Res 2024; 280:127576. [PMID: 38183754 DOI: 10.1016/j.micres.2023.127576] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Revised: 11/24/2023] [Accepted: 12/13/2023] [Indexed: 01/08/2024]
Abstract
Clostridioides difficile is a Gram-positive, anaerobic, and spore-forming bacterial member of the human gut microbiome. The primary virulence factors of C. difficile are toxin A and toxin B. These toxins damage the cell cytoskeleton and cause various diseases, from diarrhea to severe pseudomembranous colitis. Evidence suggests that bacteriophages can regulate the expression of the pathogenicity locus (PaLoc) genes of C. difficile. We previously demonstrated that the genome of the C. difficile RT027 strain NCKUH-21 contains a prophage-like DNA sequence, which was found to be markedly similar to that of the φCD38-2 phage. In the present study, we investigated the mechanisms underlying the φNCKUH-21-mediated regulation of the pathogenicity and the PaLoc genes expression in the lysogenized C. difficile strain R20291. The carriage of φNCKUH-21 in R20291 cells substantially enhanced toxin production, bacterial motility, biofilm formation, and spore germination in vitro. Subsequent mouse studies revealed that the lysogenized R20291 strain caused a more severe infection than the wild-type strain. We screened three φNCKUH-21 genes encoding DNA-binding proteins to check their effects on PaLoc genes expression. The overexpression of NCKUH-21_03890, annotated as a transcriptional regulator (phage transcriptional regulator X, PtrX), considerably enhanced toxin production, biofilm formation, and bacterial motility of R20291. Transcriptome analysis further confirmed that the overexpression of ptrX led to the upregulation of the expression of toxin genes, flagellar genes, and csrA. In the ptrX-overexpressing R20291 strain, PtrX influenced the expression of flagellar genes and the sigma factor gene sigD, possibly through an increased flagellar phase ON configuration ratio.
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Affiliation(s)
- Jun-Jia Gong
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - I-Hsiu Huang
- Department of Biochemistry and Microbiology, Oklahoma State University Center for Health Sciences, Tulsa, OK 74107, USA
| | - Marcia Shu-Wei Su
- Department of Biotechnology and Laboratory Science in Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Si-Xuan Xie
- Department of Microbiology and Immunology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Wei-Yong Liu
- Department of Microbiology and Immunology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Cheng-Rung Huang
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Yuan-Pin Hung
- Department of Microbiology and Immunology, College of Medicine, National Cheng Kung University, Tainan, Taiwan; Department of Internal Medicine, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan; Department of Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Shang-Rung Wu
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan; Institute of Oral Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Pei-Jane Tsai
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan; Department of Medical Laboratory Science and Biotechnology, National Cheng Kung University, Tainan, Taiwan; Department of Pathology, National Cheng Kung University Hospital, Tainan, Taiwan; Center for Clinical Medicine Research, National Cheng Kung University Hospital, Tainan, Taiwan
| | - Wen-Chien Ko
- Department of Internal Medicine, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan; Department of Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Jenn-Wei Chen
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan; Department of Microbiology and Immunology, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
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Li Q, Tao Q, Teixeira JS, Shu-Wei Su M, Gänzle MG. Contribution of glutaminases to glutamine metabolism and acid resistance in Lactobacillus reuteri and other vertebrate host adapted lactobacilli. Food Microbiol 2019; 86:103343. [PMID: 31703887 DOI: 10.1016/j.fm.2019.103343] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2018] [Revised: 09/17/2019] [Accepted: 09/27/2019] [Indexed: 01/13/2023]
Abstract
The bacterial conversion of glutamine to glutamate is catalyzed by glutamine-amidotransferases or glutaminases. Glutamine deamination contributes to the formation of the bioactive metabolites glutamate, γ-aminobutyrate (GABA) and γ-glutamyl peptides, and to acid resistance. This study aimed to investigate the distribution of glutaminase(s) in lactobacilli, and to evaluate their contribution in L. reuteri to amino acid metabolism and acid resistance. Phylogenetic analysis of the glutaminases gls1, gls2 and gls3 in the genus Lactobacillus demonstrated that glutaminase is exclusively present in host-adapted species of lactobacilli. The disruption gls1, gls2 and gls3 in L. reuteri 100-23 had only a limited effect on the conversion of glutamine to glutamate, GABA, or γ-glutamyl peptides in sourdough. The disruption of all glutaminases in L. reuteri 100-23Δgls1Δgls2Δgls3 but not disruption of gls2 and gls3 eliminated the protective effect of glutamine on the survival of the strain at pH 2.5. Glutamine also enhanced acid resistance of L. reuteri 100-23ΔgadB and L. taiwanensis 107q, strains without glutamate decarboxylase activity. Taken together, the study demonstrates that glutaminases of lactobacilli do not contribute substantially to glutamine metabolism but enhance acid resistance. Their exclusive presence in host-adapted lactobacilli provides an additional link between the adaptation of lactobacilli to specific habitats and their functionality when used as probiotics and starter cultures.
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Affiliation(s)
- Qing Li
- University of Alberta, Dept. of Agricultural, Food and Nutritional Science, Edmonton, Alberta, Canada
| | - QianYing Tao
- University of Alberta, Dept. of Agricultural, Food and Nutritional Science, Edmonton, Alberta, Canada
| | - Jaunana S Teixeira
- University of Alberta, Dept. of Agricultural, Food and Nutritional Science, Edmonton, Alberta, Canada
| | - Marcia Shu-Wei Su
- University of Alberta, Dept. of Agricultural, Food and Nutritional Science, Edmonton, Alberta, Canada
| | - Michael G Gänzle
- University of Alberta, Dept. of Agricultural, Food and Nutritional Science, Edmonton, Alberta, Canada; Hubei University of Technology, College of Bioengineering and Food Science, Wuhan, Hubei, PR China.
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Fungtammasan A, Ananda G, Hile SE, Su MSW, Sun C, Harris R, Medvedev P, Eckert K, Makova KD. Accurate typing of short tandem repeats from genome-wide sequencing data and its applications. Genome Res 2015; 25:736-49. [PMID: 25823460 PMCID: PMC4417121 DOI: 10.1101/gr.185892.114] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Accepted: 03/16/2015] [Indexed: 11/24/2022]
Abstract
Short tandem repeats (STRs) are implicated in dozens of human genetic diseases and contribute significantly to genome variation and instability. Yet profiling STRs from short-read sequencing data is challenging because of their high sequencing error rates. Here, we developed STR-FM, short tandem repeat profiling using flank-based mapping, a computational pipeline that can detect the full spectrum of STR alleles from short-read data, can adapt to emerging read-mapping algorithms, and can be applied to heterogeneous genetic samples (e.g., tumors, viruses, and genomes of organelles). We used STR-FM to study STR error rates and patterns in publicly available human and in-house generated ultradeep plasmid sequencing data sets. We discovered that STRs sequenced with a PCR-free protocol have up to ninefold fewer errors than those sequenced with a PCR-containing protocol. We constructed an error correction model for genotyping STRs that can distinguish heterozygous alleles containing STRs with consecutive repeat numbers. Applying our model and pipeline to Illumina sequencing data with 100-bp reads, we could confidently genotype several disease-related long trinucleotide STRs. Utilizing this pipeline, for the first time we determined the genome-wide STR germline mutation rate from a deeply sequenced human pedigree. Additionally, we built a tool that recommends minimal sequencing depth for accurate STR genotyping, depending on repeat length and sequencing read length. The required read depth increases with STR length and is lower for a PCR-free protocol. This suite of tools addresses the pressing challenges surrounding STR genotyping, and thus is of wide interest to researchers investigating disease-related STRs and STR evolution.
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Affiliation(s)
- Arkarachai Fungtammasan
- Integrative Biosciences, Bioinformatics and Genomics Option, Pennsylvania State University, University Park, Pennsylvania 16802, USA; Department of Biology, Pennsylvania State University, University Park, Pennsylvania 16802, USA; Center for Medical Genomics, Pennsylvania State University, University Park, Pennsylvania 16802, USA; The Genome Science Institute at the Huck Institutes of Life Sciences, Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Guruprasad Ananda
- Integrative Biosciences, Bioinformatics and Genomics Option, Pennsylvania State University, University Park, Pennsylvania 16802, USA; Center for Medical Genomics, Pennsylvania State University, University Park, Pennsylvania 16802, USA; The Genome Science Institute at the Huck Institutes of Life Sciences, Pennsylvania State University, University Park, Pennsylvania 16802, USA; Department of Biochemistry and Molecular Biology, Pennsylvania State University, Pennsylvania 16802, USA
| | - Suzanne E Hile
- Center for Medical Genomics, Pennsylvania State University, University Park, Pennsylvania 16802, USA; Department of Pathology, The Jake Gittlen Laboratories for Cancer Research, Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033, USA
| | - Marcia Shu-Wei Su
- Department of Biology, Pennsylvania State University, University Park, Pennsylvania 16802, USA; Center for Medical Genomics, Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Chen Sun
- Department of Computer Science and Engineering, Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Robert Harris
- Department of Biology, Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Paul Medvedev
- Center for Medical Genomics, Pennsylvania State University, University Park, Pennsylvania 16802, USA; The Genome Science Institute at the Huck Institutes of Life Sciences, Pennsylvania State University, University Park, Pennsylvania 16802, USA; Department of Biochemistry and Molecular Biology, Pennsylvania State University, Pennsylvania 16802, USA; Department of Computer Science and Engineering, Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Kristin Eckert
- Center for Medical Genomics, Pennsylvania State University, University Park, Pennsylvania 16802, USA; Department of Pathology, The Jake Gittlen Laboratories for Cancer Research, Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033, USA
| | - Kateryna D Makova
- Department of Biology, Pennsylvania State University, University Park, Pennsylvania 16802, USA; Center for Medical Genomics, Pennsylvania State University, University Park, Pennsylvania 16802, USA; The Genome Science Institute at the Huck Institutes of Life Sciences, Pennsylvania State University, University Park, Pennsylvania 16802, USA
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McElhoe JA, Holland MM, Makova KD, Su MSW, Paul IM, Baker CH, Faith SA, Young B. Development and assessment of an optimized next-generation DNA sequencing approach for the mtgenome using the Illumina MiSeq. Forensic Sci Int Genet 2014; 13:20-9. [PMID: 25051226 DOI: 10.1016/j.fsigen.2014.05.007] [Citation(s) in RCA: 85] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2013] [Revised: 05/05/2014] [Accepted: 05/11/2014] [Indexed: 12/18/2022]
Abstract
The development of molecular tools to detect and report mitochondrial DNA (mtDNA) heteroplasmy will increase the discrimination potential of the testing method when applied to forensic cases. The inherent limitations of the current state-of-the-art, Sanger-based sequencing, including constrictions in speed, throughput, and resolution, have hindered progress in this area. With the advent of next-generation sequencing (NGS) approaches, it is now possible to clearly identify heteroplasmic variants, and at a much lower level than previously possible. However, in order to bring these approaches into forensic laboratories and subsequently as accepted scientific information in a court of law, validated methods will be required to produce and analyze NGS data. We report here on the development of an optimized approach to NGS analysis for the mtDNA genome (mtgenome) using the Illumina MiSeq instrument. This optimized protocol allows for the production of more than 5 gigabases of mtDNA sequence per run, sufficient for detection and reliable reporting of minor heteroplasmic variants down to approximately 0.5-1.0% when multiplexing twelve samples. Depending on sample throughput needs, sequence coverage rates can be set at various levels, but were optimized here for at least 5000 reads. In addition, analysis parameters are provided for a commercially available software package that identify the highest quality sequencing reads and effectively filter out sequencing-based noise. With this method it will be possible to measure the rates of low-level heteroplasmy across the mtgenome, evaluate the transmission of heteroplasmy between the generations of maternal lineages, and assess the drift of variant sequences between different tissue types within an individual.
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Affiliation(s)
- Jennifer A McElhoe
- Forensic Science Program, The Pennsylvania State University, University Park, PA 16802, USA.
| | - Mitchell M Holland
- Forensic Science Program, The Pennsylvania State University, University Park, PA 16802, USA
| | - Kateryna D Makova
- Biology Department, The Pennsylvania State University, University Park, PA 16802, USA
| | - Marcia Shu-Wei Su
- Biology Department, The Pennsylvania State University, University Park, PA 16802, USA
| | - Ian M Paul
- Department of Pediatrics, Penn State College of Medicine, Hershey, PA 17033, USA
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Teixeira JS, Seeras A, Sanchez-Maldonado AF, Zhang C, Su MSW, Gänzle MG. Glutamine, glutamate, and arginine-based acid resistance in Lactobacillus reuteri. Food Microbiol 2014; 42:172-80. [PMID: 24929734 DOI: 10.1016/j.fm.2014.03.015] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2014] [Revised: 03/09/2014] [Accepted: 03/12/2014] [Indexed: 11/26/2022]
Abstract
This study aimed to determine whether glutamine deamidation improves acid resistance of Lactobacillus reuteri, and to assess whether arginine, glutamine, and glutamate-mediated acid resistance are redundant or complementary mechanisms of acid resistance. Three putative glutaminase genes, gls1, gls2, and gls3, were identified in L. reuteri 100-23. All three genes were expressed during growth in mMRS and wheat sourdough. L. reuteri consistently over-expressed gls3 and the glutamate decarboxylase gadB. L. reuteri 100-23ΔgadB over-expressed gls3 and the arginine deiminase gene adi. Analysis of the survival of L. reuteri in acidic conditions revealed that arginine conversion is effective at pH of 3.5 while glutamine or glutamate conversion were effective at pH of 2.5. Arginine conversion increased the pHin but not ΔΨ; glutamate decarboxylation had only a minor effect on the pHin but increased the ΔΨ. This study demonstrates that glutamine deamidation increases the acid resistance of L. reuteri independent of glutamate decarboxylase activity. Arginine and glutamine/glutamate conversions confer resistance to lactate at pH of 3.5 and phosphate at pH of 2.5, respectively. Knowledge of L. reuteri's acid resistance improves the understanding of the adaptation of L. reuteri to intestinal ecosystems, and facilitates the selection of probiotic and starter cultures.
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Affiliation(s)
- Januana S Teixeira
- Department of Agricultural, Food and Nutritional Science, University of Alberta, 4-10 Ag/For, Edmonton, AB, Canada T6G 2P5
| | - Arisha Seeras
- Department of Agricultural, Food and Nutritional Science, University of Alberta, 4-10 Ag/For, Edmonton, AB, Canada T6G 2P5
| | | | - Chonggang Zhang
- Department of Agricultural, Food and Nutritional Science, University of Alberta, 4-10 Ag/For, Edmonton, AB, Canada T6G 2P5
| | - Marcia Shu-Wei Su
- Department of Agricultural, Food and Nutritional Science, University of Alberta, 4-10 Ag/For, Edmonton, AB, Canada T6G 2P5
| | - Michael G Gänzle
- Department of Agricultural, Food and Nutritional Science, University of Alberta, 4-10 Ag/For, Edmonton, AB, Canada T6G 2P5.
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Dickins B, Rebolledo-Jaramillo B, Su MSW, Paul IM, Blankenberg D, Stoler N, Makova KD, Nekrutenko A. Controlling for contamination in re-sequencing studies with a reproducible web-based phylogenetic approach. Biotechniques 2014; 56:134-141. [PMID: 24641477 DOI: 10.2144/000114146] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Accepted: 01/17/2014] [Indexed: 11/23/2022] Open
Abstract
Polymorphism discovery is a routine application of next-generation sequencing technology where multiple samples are sent to a service provider for library preparation, subsequent sequencing, and bioinformatic analyses. The decreasing cost and advances in multiplexing approaches have made it possible to analyze hundreds of samples at a reasonable cost. However, because of the manual steps involved in the initial processing of samples and handling of sequencing equipment, cross-contamination remains a significant challenge. It is especially problematic in cases where polymorphism frequencies do not adhere to diploid expectation, for example, heterogeneous tumor samples, organellar genomes, as well as during bacterial and viral sequencing. In these instances, low levels of contamination may be readily mistaken for polymorphisms, leading to false results. Here we describe practical steps designed to reliably detect contamination and uncover its origin, and also provide new, Galaxy-based, readily accessible computational tools and workflows for quality control. All results described in this report can be reproduced interactively on the web as described at http://usegalaxy.org/contamination.
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Affiliation(s)
- Benjamin Dickins
- Department of Biochemistry and Molecular Biology, Penn State University, University Park, PA.,Department of Biology, Penn State University, University Park, PA
| | - Boris Rebolledo-Jaramillo
- Department of Biochemistry and Molecular Biology, Penn State University, University Park, PA.,Interdisciplinary Graduate Program in BioSciences, Penn State University, University Park, PA
| | | | - Ian M Paul
- Department of Pediatrics, Penn State College of Medicine, Hershey, PA
| | - Daniel Blankenberg
- Department of Biochemistry and Molecular Biology, Penn State University, University Park, PA
| | - Nicholas Stoler
- Interdisciplinary Graduate Program in BioSciences, Penn State University, University Park, PA
| | | | - Anton Nekrutenko
- Department of Biochemistry and Molecular Biology, Penn State University, University Park, PA
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Su MSW, Gänzle MG. Novel two-component regulatory systems play a role in biofilm formation of Lactobacillus reuteri rodent isolate 100-23. Microbiology (Reading) 2014; 160:795-806. [PMID: 24509500 DOI: 10.1099/mic.0.071399-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
This study characterized the two-component regulatory systems encoded by bfrKRT and cemAKR, and assessed their influence on biofilm formation by Lactobacillus reuteri 100-23. A method for deletion of multiple genes was employed to disrupt the genetic loci of two-component systems. The operons bfrKRT and cemAKR showed complementary organization. Genes bfrKRT encode a histidine kinase, a response regulator and an ATP-binding cassette-type transporter with a bacteriocin-processing peptidase domain, respectively. Genes cemAKR code for a signal peptide, a histidine kinase and a response regulator, respectively. Deletion of single or multiple genes in the operons bfrKRT and cemAKR did not affect cell morphology, growth or the sensitivity to various stressors. However, gene disruption affected biofilm formation; this effect was dependent on the carbon source. Deletion of bfrK or cemA increased sucrose-dependent biofilm formation in vitro. Glucose-dependent biofilm formation was particularly increased by deletion of cemK. The expression of cemK and cemR was altered by deletion of bfrK, indicating cross-talk between these two regulatory systems. These results may contribute to our understanding of the genetic factors related to the biofilm formation and competitiveness of L. reuteri in intestinal ecosystems.
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Affiliation(s)
- Marcia Shu-Wei Su
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, Canada
| | - Michael G Gänzle
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, Canada
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Su MSW, Kao HC, Lin CN, Syu WJ. Gene l0017 encodes a second chaperone for EspA of enterohaemorrhagic Escherichia coli O157 : H7. Microbiology (Reading) 2008; 154:1094-1103. [PMID: 18375802 DOI: 10.1099/mic.0.2007/013946-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Escherichia coli O157:H7 tightly associates with host cells through the formation of a pedestal structure in which cell cytoskeleton rearrangement has been observed. These pathogenic properties have been attributed to an island, known as the locus of enterocyte effacement (LEE), located on the bacterial chromosome. Gene l0017 is one of the LEE genes that has been less well characterized. To understand further the function of the gene, an l0017-deleted mutant was created. The mutant lost type III protein secretion (TTS) capacity. In terms of intracellular components, there was a substantial decrease in the level of EspA, but no apparent effect on Tir and EspB was observed. Fractionation of the bacterial proteins indicated that L0017 was part of the inner-membrane fraction. This association with the membrane is consistent with the hypothesis that L0017 may act as one of the TTS components. In addition, L0017 was found to affect regulation of EspA at a post-transcriptional level. The presence of L0017 readily stabilized EspA and the interaction between L0017 and EspA was demonstrated by their co-purification as well as by a bacterial two-hybrid system. Therefore, L0017 is a chaperone, the second chaperone identified in this system after CesAB, and escorts EspA, a protein with a great tendency to polymerize.
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Affiliation(s)
- Marcia Shu-Wei Su
- Institute of Microbiology and Immunology, National Yang-Ming University, Beitou 112, Taipei, Taiwan
| | - Hsi-Chun Kao
- Institute of Microbiology and Immunology, National Yang-Ming University, Beitou 112, Taipei, Taiwan
| | - Ching-Nan Lin
- Institute of Microbiology and Immunology, National Yang-Ming University, Beitou 112, Taipei, Taiwan
| | - Wan-Jr Syu
- Institute of Microbiology and Immunology, National Yang-Ming University, Beitou 112, Taipei, Taiwan
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