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Hu Q, Wang J, Liu C, Feng Y, Chen H. Determinants of mer Promoter Activity from Pseudomonas aeruginosa. Genes (Basel) 2024; 15:490. [PMID: 38674424 PMCID: PMC11049809 DOI: 10.3390/genes15040490] [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: 03/18/2024] [Revised: 04/11/2024] [Accepted: 04/12/2024] [Indexed: 04/28/2024] Open
Abstract
Since the MerR family is known for its special regulatory mechanism, we aimed to explore which factors determine the expression activity of the mer promoter. The Tn501/Tn21 mer promoter contains an abnormally long spacer (19 bp) between the -35 and -10 elements, which is essential for the unique DNA distortion mechanism. To further understand the role of base sequences in the mer promoter spacer, this study systematically engineered a series of mutant derivatives and used luminescent and fluorescent reporter genes to investigate the expression activity of these derivatives. The results reveal that the expression activity of the mer promoter is synergistically modulated by the spacer length (17 bp is optimal) and the region upstream of -10 (especially -13G). The spacing is regulated by MerR transcription factors through symmetrical sequences, and -13G presumably functions through interaction with the RNA polymerase sigma-70 subunit.
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Affiliation(s)
| | | | | | | | - Hao Chen
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China; (Q.H.); (J.W.); (C.L.); (Y.F.)
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2
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Ju X, Li S, Froom R, Wang L, Lilic M, Delbeau M, Campbell EA, Rock JM, Liu S. Incomplete transcripts dominate the Mycobacterium tuberculosis transcriptome. Nature 2024; 627:424-430. [PMID: 38418874 PMCID: PMC10937400 DOI: 10.1038/s41586-024-07105-9] [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: 11/14/2022] [Accepted: 01/23/2024] [Indexed: 03/02/2024]
Abstract
Mycobacterium tuberculosis (Mtb) is a bacterial pathogen that causes tuberculosis (TB), an infectious disease that is responsible for major health and economic costs worldwide1. Mtb encounters diverse environments during its life cycle and responds to these changes largely by reprogramming its transcriptional output2. However, the mechanisms of Mtb transcription and how they are regulated remain poorly understood. Here we use a sequencing method that simultaneously determines both termini of individual RNA molecules in bacterial cells3 to profile the Mtb transcriptome at high resolution. Unexpectedly, we find that most Mtb transcripts are incomplete, with their 5' ends aligned at transcription start sites and 3' ends located 200-500 nucleotides downstream. We show that these short RNAs are mainly associated with paused RNA polymerases (RNAPs) rather than being products of premature termination. We further show that the high propensity of Mtb RNAP to pause early in transcription relies on the binding of the σ-factor. Finally, we show that a translating ribosome promotes transcription elongation, revealing a potential role for transcription-translation coupling in controlling Mtb gene expression. In sum, our findings depict a mycobacterial transcriptome that prominently features incomplete transcripts resulting from RNAP pausing. We propose that the pausing phase constitutes an important transcriptional checkpoint in Mtb that allows the bacterium to adapt to environmental changes and could be exploited for TB therapeutics.
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Affiliation(s)
- Xiangwu Ju
- Laboratory of Nanoscale Biophysics and Biochemistry, The Rockefeller University, New York, NY, USA
| | - Shuqi Li
- Laboratory of Host-Pathogen Biology, The Rockefeller University, New York, NY, USA
| | - Ruby Froom
- Laboratory of Host-Pathogen Biology, The Rockefeller University, New York, NY, USA
- Laboratory of Molecular Biophysics, The Rockefeller University, New York, NY, USA
| | - Ling Wang
- Laboratory of Nanoscale Biophysics and Biochemistry, The Rockefeller University, New York, NY, USA
| | - Mirjana Lilic
- Laboratory of Molecular Biophysics, The Rockefeller University, New York, NY, USA
| | - Madeleine Delbeau
- Laboratory of Molecular Biophysics, The Rockefeller University, New York, NY, USA
| | - Elizabeth A Campbell
- Laboratory of Molecular Biophysics, The Rockefeller University, New York, NY, USA
| | - Jeremy M Rock
- Laboratory of Host-Pathogen Biology, The Rockefeller University, New York, NY, USA.
| | - Shixin Liu
- Laboratory of Nanoscale Biophysics and Biochemistry, The Rockefeller University, New York, NY, USA.
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3
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Genomic and Functional Dissections of Dickeya zeae Shed Light on the Role of Type III Secretion System and Cell Wall-Degrading Enzymes to Host Range and Virulence. Microbiol Spectr 2022; 10:e0159021. [PMID: 35107329 PMCID: PMC8809351 DOI: 10.1128/spectrum.01590-21] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Dickeya zeae is a worldwide destructive pathogen that causes soft rot diseases on various hosts such as rice, maize, banana, and potato. The strain JZL7 we recently isolated from clivia represents the first monocot-specific D. zeae and also has reduced pathogenicity compared to that of other D. zeae strains (e.g., EC1 and MS2). To elucidate the molecular mechanisms underlying its more restricted host range and weakened pathogenicity, we sequenced the complete genome of JZL7 and performed comparative genomic and functional analyses of JZL7 and other D. zeae strains. We found that, while having the largest genome among D. zeae strains, JZL7 lost almost the entire type III secretion system (T3SS), which is a key component of the virulence suite of many bacterial pathogens. Importantly, the deletion of T3SS in MS2 substantially diminished the expression of most type III secreted effectors (T3SEs) and MS2's pathogenicity on both dicots and monocots. Moreover, although JZL7 and MS2 share almost the same repertoire of cell wall-degrading enzymes (CWDEs), we found broad reduction in the production of CWDEs and expression levels of CWDE genes in JZL7. The lower expression of CWDEs, pectin lyases in particular, would probably make it difficult for JZL7 to break down the cell wall of dicots, which is rich in pectin. Together, our results suggest that the loss of T3SS and reduced CWDE activity together might have contributed to the host specificity and virulence of JZL7. Our findings also shed light on the pathogenic mechanism of Dickeya and other soft rot Pectobacteriaceae species in general. IMPORTANCE Dickeya zeae is an important, aggressive bacterial phytopathogen that can cause severe diseases in many crops and ornamental plants, thus leading to substantial economic losses. Strains from different sources showed significant diversity in their natural hosts, suggesting complicated evolution history and pathogenic mechanisms. However, molecular mechanisms that cause the differences in the host range of D. zeae strains remain poorly understood. This study carried out genomic and functional dissections of JZL7, a D. zeae strain with restricted host range, and revealed type III secretion system (T3SS) and cell wall-degrading enzymes (CWDEs) as two major factors contributing to the host range and virulence of D. zeae, which will provide a valuable reference for the exploration of pathogenic mechanisms in other bacteria and present new insights for the control of bacterial soft rot diseases on crops.
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Pletnev P, Pupov D, Pshanichnaya L, Esyunina D, Petushkov I, Nesterchuk M, Osterman I, Rubtsova M, Mardanov A, Ravin N, Sergiev P, Kulbachinskiy A, Dontsova O. Rewiring of growth-dependent transcription regulation by a point mutation in region 1.1 of the housekeeping σ factor. Nucleic Acids Res 2020; 48:10802-10819. [PMID: 32997144 PMCID: PMC7641759 DOI: 10.1093/nar/gkaa798] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Revised: 09/09/2020] [Accepted: 09/12/2020] [Indexed: 01/24/2023] Open
Abstract
In bacteria, rapid adaptation to changing environmental conditions depends on the interplay between housekeeping and alternative σ factors, responsible for transcription of specific regulons by RNA polymerase (RNAP). In comparison with alternative σ factors, primary σs contain poorly conserved region 1.1, whose functions in transcription are only partially understood. We found that a single mutation in region 1.1 in Escherichia coli σ70 rewires transcription regulation during cell growth resulting in profound phenotypic changes. Despite its destabilizing effect on promoter complexes, this mutation increases the activity of rRNA promoters and also decreases RNAP sensitivity to the major regulator of stringent response DksA. Using total RNA sequencing combined with single-cell analysis of gene expression we showed that changes in region 1.1 disrupt the balance between the "greed" and "fear" strategies thus making the cells more susceptible to environmental threats and antibiotics. Our results reveal an unexpected role of σ region 1.1 in growth-dependent transcription regulation and suggest that changes in this region may facilitate rapid switching of RNAP properties in evolving bacterial populations.
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Affiliation(s)
- Philipp Pletnev
- Department of Chemistry, Lomonosov Moscow State University, Moscow 119992, Russia.,Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Moscow 117997, Russia
| | - Danil Pupov
- Institute of Molecular Genetics, Russian Academy of Sciences, Moscow,123182, Russia
| | | | - Daria Esyunina
- Institute of Molecular Genetics, Russian Academy of Sciences, Moscow,123182, Russia
| | - Ivan Petushkov
- Institute of Molecular Genetics, Russian Academy of Sciences, Moscow,123182, Russia
| | - Mikhail Nesterchuk
- Skolkovo Institute of Science and Technology, Skolkovo, Moscow Region 143028, Russia
| | - Ilya Osterman
- Department of Chemistry, Lomonosov Moscow State University, Moscow 119992, Russia.,Skolkovo Institute of Science and Technology, Skolkovo, Moscow Region 143028, Russia
| | - Maria Rubtsova
- Department of Chemistry, Lomonosov Moscow State University, Moscow 119992, Russia.,Skolkovo Institute of Science and Technology, Skolkovo, Moscow Region 143028, Russia
| | - Andrey Mardanov
- Institute of Bioengineering, Research Center of Biotechnology of the Russian Academy of Sciences, Moscow, Russia
| | - Nikolai Ravin
- Institute of Bioengineering, Research Center of Biotechnology of the Russian Academy of Sciences, Moscow, Russia
| | - Petr Sergiev
- Department of Chemistry, Lomonosov Moscow State University, Moscow 119992, Russia.,Skolkovo Institute of Science and Technology, Skolkovo, Moscow Region 143028, Russia.,Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow 119992, Russia.,Institute of Functional Genomics, Lomonosov Moscow State University, Moscow 119992, Russia
| | - Andrey Kulbachinskiy
- Institute of Molecular Genetics, Russian Academy of Sciences, Moscow,123182, Russia
| | - Olga Dontsova
- Department of Chemistry, Lomonosov Moscow State University, Moscow 119992, Russia.,Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Moscow 117997, Russia.,Skolkovo Institute of Science and Technology, Skolkovo, Moscow Region 143028, Russia.,Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow 119992, Russia
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5
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Kuo HH, Huang WC, Lin TF, Yeh HY, Liou KM, Chang BY. The core-independent promoter-specific binding of Bacillus subtilis σB. FEBS J 2015; 282:1307-18. [PMID: 25652417 DOI: 10.1111/febs.13222] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2014] [Revised: 12/18/2014] [Accepted: 01/21/2015] [Indexed: 11/28/2022]
Abstract
Bacillus subtilis σ(D) is an alternative σ factor that possesses a core-independent promoter -10 element binding specificity despite the lack of a distinct footprint on its cognate promoter. We wished to determine whether this property is common to alternative σ factors. To this end, we over-expressed B. subtilis σ(B) in Escherichia coli and analyzed its DNA binding ability by electrophoretic mobility shift assay and DNase I footprinting. The major complex formed by σ(B) and its cognate promoter DNA is heparin-sensitive. However, in contrast to the -10 element binding specificity observed for B. subtilis σ(D) , the promoter binding of σ(B) is specific for the -35 element. These and other results clearly demonstrate that alternative σ factors possess different promoter-binding characteristics, and make core-independent contributions to recognition of their cognate promoters.
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Affiliation(s)
- Heng-Hsu Kuo
- Institute of Biochemistry, National Chung-Hsing University, Taichung, Taiwan
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6
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Liu SP, Yu P, Yuan PH, Zhou ZX, Bu QT, Mao XM, Li YQ. Sigma factor WhiGch positively regulates natamycin production in Streptomyces chattanoogensis L10. Appl Microbiol Biotechnol 2015; 99:2715-26. [DOI: 10.1007/s00253-014-6307-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2014] [Revised: 12/06/2014] [Accepted: 12/09/2014] [Indexed: 12/22/2022]
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7
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The reduction in σ-promoter recognition flexibility as induced by core RNAP is required for σ to discern the optimal promoter spacing. Biochem J 2013; 455:185-93. [PMID: 23875654 DOI: 10.1042/bj20130576] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Sigma (σ) factors are bacterial transcription initiation factors that direct transcription at cognate promoters. The promoters recognized by primary σ are composed of -10 and -35 consensus elements separated by a spacer of 17±1 bp for optimal activity. However, how the optimal promoter spacing is sensed by the primary σ remains unclear. In the present study, we examined this issue using a transcriptionally active Bacillus subtilis N-terminally truncated σA (SND100-σA). The results of the present study demonstrate that SND100-σA binds specifically to both the -10 and -35 elements of the trnS spacing variants, of which the spacer lengths range from 14 to 21 bp, indicating that simultaneous and specific recognition of promoter -10 and -35 elements is insufficient for primary σ to discern the optimal promoter spacing. Moreover, shortening in length of the flexible linker between the two promoter DNA-binding domains of σA also does not enable SND100-σA to sense the optimal promoter spacing. Efficient recognition of optimal promoter spacing by SND100-σA requires core RNAP (RNA polymerase) which reduces the flexibility of simultaneous and specific binding of SND100-σA to both promoter -10 and -35 elements. Thus the discrimination of optimal promoter spacing by σ is core-dependent.
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8
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Wang L, Zhang L, Liu Z, Zhao D, Liu X, Zhang B, Xie J, Hong Y, Li P, Chen S, Dixon R, Li J. A minimal nitrogen fixation gene cluster from Paenibacillus sp. WLY78 enables expression of active nitrogenase in Escherichia coli. PLoS Genet 2013; 9:e1003865. [PMID: 24146630 PMCID: PMC3798268 DOI: 10.1371/journal.pgen.1003865] [Citation(s) in RCA: 92] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2013] [Accepted: 08/21/2013] [Indexed: 11/23/2022] Open
Abstract
Most biological nitrogen fixation is catalyzed by molybdenum-dependent nitrogenase, an enzyme complex comprising two component proteins that contains three different metalloclusters. Diazotrophs contain a common core of nitrogen fixation nif genes that encode the structural subunits of the enzyme and components required to synthesize the metalloclusters. However, the complement of nif genes required to enable diazotrophic growth varies significantly amongst nitrogen fixing bacteria and archaea. In this study, we identified a minimal nif gene cluster consisting of nine nif genes in the genome of Paenibacillus sp. WLY78, a gram-positive, facultative anaerobe isolated from the rhizosphere of bamboo. We demonstrate that the nif genes in this organism are organized as an operon comprising nifB, nifH, nifD, nifK, nifE, nifN, nifX, hesA and nifV and that the nif cluster is under the control of a σ70 (σA)-dependent promoter located upstream of nifB. To investigate genetic requirements for diazotrophy, we transferred the Paenibacillus nif cluster to Escherichia coli. The minimal nif gene cluster enables synthesis of catalytically active nitrogenase in this host, when expressed either from the native nifB promoter or from the T7 promoter. Deletion analysis indicates that in addition to the core nif genes, hesA plays an important role in nitrogen fixation and is responsive to the availability of molybdenum. Whereas nif transcription in Paenibacillus is regulated in response to nitrogen availability and by the external oxygen concentration, transcription from the nifB promoter is constitutive in E. coli, indicating that negative regulation of nif transcription is bypassed in the heterologous host. This study demonstrates the potential for engineering nitrogen fixation in a non-nitrogen fixing organism with a minimum set of nine nif genes. Biological nitrogen fixation plays an essential role in the nitrogen cycle, sustaining agricultural productivity by providing a source of fixed nitrogen for plants and ultimately animals. The enzyme nitrogenase that catalyses the reduction of atmospheric dinitrogen to ammonia contains one of the most complex heterometal cofactors found in biology. Biosynthesis of nitrogenase and provision of support for its activity requires a large number of nitrogen fixation (nif) genes, which vary according to the physiological lifestyle of the host organism. In this study, we identified a nif cluster with reduced genetic complexity, consisting of nine genes organized as a single operon in the genome of Paenibacillus sp. WLY78. When transferred to Escherichia coli, the Paenibacllus nif cluster enables synthesis of catalytically active nitrogenase, which is competent to reduce both acetylene and dinitrogen as substrates of the enzyme. Environmental regulation of nif gene expression in Paenibacillus, in response to either oxygen or fixed nitrogen, is circumvented when the nif operon is expressed from its native promoter in E. coli, suggesting that nif transcription in Paenibacillus is negatively regulated in response to these effectors.
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Affiliation(s)
- Liying Wang
- State Key Laboratory for Agrobiotechnology and College of Biological Sciences, China Agricultural University, Beijing, P. R. China
| | - Lihong Zhang
- State Key Laboratory for Agrobiotechnology and College of Biological Sciences, China Agricultural University, Beijing, P. R. China
- College of Life Science, Shanxi Normal University, Linfen, P. R. China
| | - Zhangzhi Liu
- State Key Laboratory for Agrobiotechnology and College of Biological Sciences, China Agricultural University, Beijing, P. R. China
| | - Dehua Zhao
- Synthetic Biology Center, Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Xiaomeng Liu
- State Key Laboratory for Agrobiotechnology and College of Biological Sciences, China Agricultural University, Beijing, P. R. China
| | - Bo Zhang
- State Key Laboratory for Agrobiotechnology and College of Biological Sciences, China Agricultural University, Beijing, P. R. China
| | - Jianbo Xie
- State Key Laboratory for Agrobiotechnology and College of Biological Sciences, China Agricultural University, Beijing, P. R. China
| | - Yuanyuan Hong
- State Key Laboratory for Agrobiotechnology and College of Biological Sciences, China Agricultural University, Beijing, P. R. China
| | - Pengfei Li
- State Key Laboratory for Agrobiotechnology and College of Biological Sciences, China Agricultural University, Beijing, P. R. China
| | - Sanfeng Chen
- State Key Laboratory for Agrobiotechnology and College of Biological Sciences, China Agricultural University, Beijing, P. R. China
- * E-mail: (SC); (RD)
| | - Ray Dixon
- Department of Molecular Microbiology, John Innes Centre, Norwich, United Kingdom
- * E-mail: (SC); (RD)
| | - Jilun Li
- State Key Laboratory for Agrobiotechnology and College of Biological Sciences, China Agricultural University, Beijing, P. R. China
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Mao XM, Sun N, Wang F, Luo S, Zhou Z, Feng WH, Huang FL, Li YQ. Dual positive feedback regulation of protein degradation of an extra-cytoplasmic function σ factor for cell differentiation in Streptomyces coelicolor. J Biol Chem 2013; 288:31217-28. [PMID: 24014034 DOI: 10.1074/jbc.m113.491498] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Here we report that in Streptomyces coelicolor, the protein stability of an ECF σ factor SigT, which is involved in the negative regulation of cell differentiation, was completely dependent on its cognate anti-σ factor RstA. The degradation of RstA caused a ClpP/SsrA-dependent degradation of SigT during cell differentiation. This was consistent with the delayed morphological development or secondary metabolism in the ΔclpP background after rstA deletion or sigT overexpression. Meanwhile, SigT negatively regulated clpP/ssrA expression by directly binding to the clpP promoter (clpPp). The SigT-clpPp interaction could be disrupted by secondary metabolites, giving rise to the stabilized SigT protein and retarded morphological development in a non-antibiotic-producing mutant. Thus a novel regulatory mechanism was revealed that the protein degradation of the ECF σ factor was initiated by the degradation of its anti-σ factor, and was accelerated in a dual positive feedback manner, through regulation by secondary metabolites, to promote rapid and irreversible development of the secondary metabolism. This ingenious cooperation of intracellular components can ensure economical and exquisite control of the ECF σ factor protein level for the proper cell differentiation in Streptomyces.
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Affiliation(s)
- Xu-Ming Mao
- From the College of Life Sciences, Zhejiang University, Hangzhou 310058 and
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Lin MH, Fu JF, Liu ST. A repeat sequence causes competition of ColE1-type plasmids. PLoS One 2013; 8:e61668. [PMID: 23613898 PMCID: PMC3628316 DOI: 10.1371/journal.pone.0061668] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2012] [Accepted: 03/11/2013] [Indexed: 11/18/2022] Open
Abstract
Plasmid pSW200 from Pantoea stewartii contains 41 copies of 15-bp repeats and has a replicon that is homologous to that of ColE1. Although deleting the repeats (pSW207) does not change the copy number and stability of the plasmid. The plasmid becomes unstable and is rapidly lost from the host when a homoplasmid with the repeats (pSW201) is present. Deleting the repeats is found to reduce the transcriptional activity of RNAIp and RNAIIp by about 30%, indicating that the repeats promote the transcription of RNAI and RNAII, and how the RNAI that is synthesized by pSW201 inhibits the replication of pSW207. The immunoblot analysis herein demonstrates that RNA polymerase β subunit and σ(70) in the lysate from Escherichia coli MG1655 bind to a biotin-labeled DNA probe that contains the entire sequence of the repeat region. Electrophoretic mobility shift assay also reveals that purified RNA polymerase shifts a DNA probe that contains four copies of the repeats. These results thus obtained reveal that RNA polymerase holoenzyme binds to the repeats. The repeats also exchange RNA polymerase with RNAIp and RNAIIp in vitro, revealing the mechanism by which the transcription is promoted. This investigation elucidates a mechanism by which a plasmid prevents the invasion of an incompatible plasmid and maintains its stability in the host cell during evolution.
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Affiliation(s)
- Mei-Hui Lin
- Department of Medical Biotechnology and Laboratory Science, College of Medicine, Chang Gung University, Taoyuan, Taiwan
- Research Center for Pathogenic Bacteria, Chang Gung University, Taoyuan, Taiwan
| | - Jen-Fen Fu
- Department of Medical Research, Chang Gung Memorial Hospital, and Graduate Institute of Clinical Medical Sciences Taoyuan, Taiwan
| | - Shih-Tung Liu
- Department of Microbiology and Immunology, College of Medicine, Chang Gung University, Taoyuan, Taiwan
- Research Center for Pathogenic Bacteria, Chang Gung University, Taoyuan, Taiwan
- * E-mail:
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