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Bharathan G, Mundra S, Darwich DM, Saeed MM, Al Hafri ASA, Alsalmi MMSM, Maqsood S, Mudgil P, Fanning S, Srikumar S. Regulation of iron metabolism is critical for the survival of Salmonella Typhimurium in pasteurized milk. Food Microbiol 2023; 115:104326. [PMID: 37567619 DOI: 10.1016/j.fm.2023.104326] [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: 02/06/2023] [Revised: 06/13/2023] [Accepted: 06/14/2023] [Indexed: 08/13/2023]
Abstract
Salmonella is known to survive in raw/pasteurized milk and cause foodborne outbreaks. Lactoferrin, present in milk from all animal sources, is an iron-binding glycoprotein that limits the availability of iron to pathogenic bacteria. Despite the presence of lactoferrins, Salmonella can grow in milk obtained from different animal sources. However, the mechanism by which Salmonella overcomes iron scarcity induced by lactoferrin in milk is not evaluated yet. Salmonella employs the DNA binding transcriptional regulator Fur (ferric update regulator) to mediate iron uptake during survival in iron deplete conditions. To understand the importance of Fur in Salmonella milk growth, we profiled the growth of Salmonella Typhimurium Δfur (ST4/74Δfur) in both bovine and camel milk. ST4/74Δfur was highly inhibited in milk compared to wild-type ST4/74, confirming the importance of Fur mediated regulation of iron metabolism in Salmonella milk growth. We further studied the biology of ST4/74Δfur to understand the importance of iron metabolism in Salmonella milk survival. Using increasing concentrations of FeCl3, and the antibiotic streptonigrin we show that iron accumulates in the cytoplasm of ST4/74Δfur. We hypothesized that the accumulated iron could activate oxidative stress via Fenton's reaction leading to growth inhibition. However, the inhibition of ST4/74Δfur in milk was not due to Fenton's reaction, but due to the 'iron scarce' conditions of milk and microaerophilic incubation conditions which made the presence of the fur gene indispensable for Salmonella milk growth. Subsequently, survival studies of 14 other transcriptional mutants of ST4/74 in milk confirmed that RpoE-mediated response to extracytoplasmic stress is also important for the survival of Salmonella in milk. Though we have data only for fur and rpoE, many other Salmonella transcriptional factors could play important roles in the growth of Salmonella in milk, a theme for future research on Salmonella milk biology. Nevertheless, our data provide early insights into the biology of milk-associated Salmonella.
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Affiliation(s)
- Greeshma Bharathan
- Department of Food Science, College of Agriculture and Veterinary Medicine, UAE University, Al Ain, 15551, United Arab Emirates
| | - Sunil Mundra
- Department of Biology, College of Science, United Arab Emirates University, Al Ain, 15551, United Arab Emirates; Khalifa Centre for Genetic Engineering and Biotechnology, United Arab Emirates University, Al Ain, 15551, United Arab Emirates
| | - Dania Mustafa Darwich
- Department of Food Science, College of Agriculture and Veterinary Medicine, UAE University, Al Ain, 15551, United Arab Emirates
| | - Maitha Mohammad Saeed
- Department of Food Science, College of Agriculture and Veterinary Medicine, UAE University, Al Ain, 15551, United Arab Emirates
| | - Ahad Saeed Ali Al Hafri
- Department of Food Science, College of Agriculture and Veterinary Medicine, UAE University, Al Ain, 15551, United Arab Emirates
| | | | - Sajid Maqsood
- Department of Food Science, College of Agriculture and Veterinary Medicine, UAE University, Al Ain, 15551, United Arab Emirates
| | - Priti Mudgil
- Department of Food Science, College of Agriculture and Veterinary Medicine, UAE University, Al Ain, 15551, United Arab Emirates
| | - Séamus Fanning
- UCD-Centre for Food Safety, Science Centre South, University College Dublin, Dublin, D04 N2E5, Ireland
| | - Shabarinath Srikumar
- Department of Food Science, College of Agriculture and Veterinary Medicine, UAE University, Al Ain, 15551, United Arab Emirates.
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Rom JS, Le Breton Y, Islam E, Belew AT, El-Sayed NM, McIver KS. Loss of rpoE Encoding the δ-Factor of RNA Polymerase Impacts Pathophysiology of the Streptococcus pyogenes M1T1 Strain 5448. Microorganisms 2022; 10:microorganisms10081686. [PMID: 36014103 PMCID: PMC9412562 DOI: 10.3390/microorganisms10081686] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 08/08/2022] [Accepted: 08/19/2022] [Indexed: 12/01/2022] Open
Abstract
Streptococcus pyogenes, also known as the Group A Streptococcus (GAS), is a Gram-positive bacterial pathogen of major clinical significance. Despite remaining relatively susceptible to conventional antimicrobial therapeutics, GAS still causes millions of infections and hundreds of thousands of deaths each year worldwide. Thus, a need for prophylactic and therapeutic interventions for GAS is in great demand. In this study, we investigated the importance of the gene encoding the delta (δ) subunit of the GAS RNA polymerase, rpoE, for its impact on virulence during skin and soft-tissue infection. A defined 5448 mutant with an insertionally-inactivated rpoE gene was defective for survival in whole human blood and was attenuated for both disseminated lethality and lesion size upon mono-culture infection in mouse soft tissue. Furthermore, the mutant had reduced competitive fitness when co-infected with wild type (WT) 5448 in the mouse model. We were unable to attribute this attenuation to any observable growth defect, although colony size and the ability to grow at higher temperatures were both affected when grown with nutrient-rich THY media. RNA-seq of GAS grown in THY to late log phase found that mutation of rpoE significantly impacted (>2-fold) the expression of 429 total genes (205 upregulated, 224 downregulated), including multiple virulence and “housekeeping” genes. The arc operon encoding the arginine deiminase (ADI) pathway was the most upregulated in the rpoE mutant and this could be confirmed phenotypically. Taken together, these findings demonstrate that the delta (δ) subunit of RNA polymerase is vital in GAS gene expression and virulence.
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3
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Hews CL, Pritchard EJ, Rowley G. The Salmonella Specific, σ E-Regulated, STM1250 and AgsA, Function With the sHsps IbpA and IbpB, to Counter Oxidative Stress and Survive Macrophage Killing. Front Cell Infect Microbiol 2019; 9:263. [PMID: 31396489 PMCID: PMC6663981 DOI: 10.3389/fcimb.2019.00263] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Accepted: 07/04/2019] [Indexed: 11/13/2022] Open
Abstract
The host presents an array of environments which induce bacterial stress including changes in pH, antimicrobial compounds and reactive oxygen species. The bacterial envelope sits at the interface between the intracellular and extracellular environment and its maintenance is essential for Salmonella cell viability under a range of conditions, including during infection. In this study, we aimed to understand the contribution of the σH- and σE-regulated small heat shock proteins IbpA, IbpB, and AgsA and the putative σE-regulated stress response protein STM1250 to the Salmonella envelope stress response. Due to shared sequence identity, regulatory overlap, and the specificity of STM1250 and AgsA to Salmonella sp., we hypothesized that functional overlap exists between these four stress response proteins, which might afford a selective advantage during Salmonella exposure to stress. We present here new roles for three small heat shock proteins and a putative stress response protein in Salmonella that are not limited to heat shock. We have shown that, compared to WT, a quadruple mutant is significantly more sensitive to hydrogen peroxide, has a lower minimum bactericidal concentration to the cationic antimicrobial peptide polymyxin B, and is attenuated in macrophages.
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Affiliation(s)
- Claire L Hews
- School of Biological Sciences, University of East Anglia, Norwich, United Kingdom
| | - Emily J Pritchard
- School of Biological Sciences, University of East Anglia, Norwich, United Kingdom
| | - Gary Rowley
- School of Biological Sciences, University of East Anglia, Norwich, United Kingdom
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4
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Huang L, Zhang Y, He R, Zuo Z, Luo Z, Xu W, Yan Q. Phenotypic characterization, virulence, and immunogenicity of Pseudomonas plecoglossicida rpoE knock-down strain. Fish Shellfish Immunol 2019; 87:772-777. [PMID: 30776544 DOI: 10.1016/j.fsi.2019.02.028] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Revised: 02/13/2019] [Accepted: 02/15/2019] [Indexed: 06/09/2023]
Abstract
Pseudomonas plecoglossicida, a temperature dependent bacterial pathogen in fish, expresses rpoE gene that is sensitive to temperature and probably critical for pathogen virulence and disease development. In this study, the rpoE silence strain rpoE-RNAi-1 was constructed by gene knock-down. The rpoE-RNAi-1 displayed significant changes in biofilm formation, swarming motility, adhesion and virulence. Meanwhile, vaccination of grouper with rpoE-RNAi-1 led to a relative percent survival (RPS) value of 85% after challenged with the wild-type P. plecoglossicida. qRT-PCR assays showed that vaccination with rpoE-RNAi-1 enhanced the expression of immune-related genes, including MHC-I, MHC-II, IgM, and IL-1β, indicating that it was able to induce humoral and cell-mediated immune response in grouper. These results validated the possibility of rpoE as a potential target for constructing P. plecoglossicida live attenuated vaccine.
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Affiliation(s)
- Lixing Huang
- Fisheries College, Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture, Jimei University, Xiamen, Fujian, PR China.
| | - Youyu Zhang
- Institute of Electromagnetics and Acoustics, School of Electronic Science and Engineering, Xiamen University, Xiamen, Fujian, PR China
| | - Rongchao He
- Fisheries College, Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture, Jimei University, Xiamen, Fujian, PR China
| | - Zhenghong Zuo
- School of Life Sciences, Xiamen University, Xiamen, Fujian, PR China
| | - Zhuhua Luo
- Third Institute of Oceanography, State Oceanic Administration, Xiamen, 361005, PR China
| | - Wei Xu
- Third Institute of Oceanography, State Oceanic Administration, Xiamen, 361005, PR China
| | - Qingpi Yan
- Fisheries College, Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture, Jimei University, Xiamen, Fujian, PR China.
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Amar A, Pezzoni M, Pizarro RA, Costa CS. New envelope stress factors involved in σ E activation and conditional lethality of rpoE mutations in Salmonella enterica. Microbiology (Reading) 2018; 164:1293-1307. [PMID: 30084765 DOI: 10.1099/mic.0.000701] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Salmonella enterica serovar Typhimurium (S. typhimurium) can cause food- and water-borne illness with diverse clinical manifestations. One key factor for S. typhimurium pathogenesis is the alternative sigma factor σE, which is encoded by the rpoE gene and controls the transcription of genes required for outer-membrane integrity in response to alterations in the bacterial envelope. The canonical pathway for σE activation involves proteolysis of the antisigma factor RseA, which is triggered by unfolded outer-membrane porins (OMPs) and lipopolysaccharides (LPS) that have accumulated in the periplasm. This study reports new stress factors that are able to activate σE expression. We demonstrate that UVA radiation induces σE activity in a pathway that is dependent on the stringent response regulator ppGpp. Survival assays revealed that rpoE has a role in the defence against lethal UVA doses that is mediated by functions that are dependent on and independent of the alternative sigma factor RpoS. We also report that the envelope stress generated by phage infection requires a functional rpoE gene for optimal bacterial tolerance and that it is able to induce σE activity in an RseA-dependent fashion. σE activity is also induced by hypo-osmotic shock in the absence of osmoregulated periplasmic glucans (OPGs). It is known that the rpoE gene is not essential in S. typhimurium. However, we report here two cases of the conditional lethality of rpoE mutations in this micro-organism. We demonstrate that rpoE mutations are not tolerated in the absence of OPGs (at low to moderate osmolarity) or LPS O-antigen. The latter case resembles that of the prototypic Escherichia coli strain K12, which neither synthesizes a complete LPS nor tolerates null rpoE mutations.
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Affiliation(s)
- Agustina Amar
- Dpto. de Radiobiología, Comisión Nacional de Energía Atómica, General San Martín, Argentina
| | - Magdalena Pezzoni
- Dpto. de Radiobiología, Comisión Nacional de Energía Atómica, General San Martín, Argentina
| | - Ramón A Pizarro
- Dpto. de Radiobiología, Comisión Nacional de Energía Atómica, General San Martín, Argentina
| | - Cristina S Costa
- Dpto. de Radiobiología, Comisión Nacional de Energía Atómica, General San Martín, Argentina
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6
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Held K, Gasper J, Morgan S, Siehnel R, Singh P, Manoil C. Determinants of Extreme β-Lactam Tolerance in the Burkholderia pseudomallei Complex. Antimicrob Agents Chemother 2018; 62:e00068-18. [PMID: 29439964 DOI: 10.1128/AAC.00068-18] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Accepted: 02/04/2018] [Indexed: 12/22/2022] Open
Abstract
Slow-growing bacteria are insensitive to killing by antibiotics, a trait known as antibiotic tolerance. In this study, we characterized the genetic basis of an unusually robust β-lactam (meropenem) tolerance seen in Burkholderia species. We identified tolerance genes under three different slow-growth conditions by extensive transposon mutant sequencing (Tn-seq), followed by single mutant validation. There were three principal findings. First, mutations in a small number of genes reduced tolerance under multiple conditions. Most of the functions appeared to be specific to peptidoglycan synthesis and the response to its disruption by meropenem action rather than being associated with more general physiological processes. The top tolerance genes are involved in immunity toward a type VI toxin targeting peptidoglycan (BTH_I0069), peptidoglycan recycling (ldcA), periplasmic regulation by proteolysis (prc), and an envelope stress response (rpoE and degS). Second, most of the tolerance functions did not contribute to growth in the presence of meropenem (intrinsic resistance), indicating that the two traits are largely distinct. Third, orthologues of many of the top Burkholderia thailandensis tolerance genes were also important in Burkholderia pseudomallei Overall, these studies show that the determinants of meropenem tolerance differ considerably depending on cultivation conditions, but that there are a few shared functions with strong mutant phenotypes that are important in multiple Burkholderia species.
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Li H, Liu F, Peng W, Yan K, Zhao H, Liu T, Cheng H, Chang P, Yuan F, Chen H, Bei W. The CpxA/CpxR Two-Component System Affects Biofilm Formation and Virulence in Actinobacillus pleuropneumoniae. Front Cell Infect Microbiol 2018; 8:72. [PMID: 29662838 PMCID: PMC5890194 DOI: 10.3389/fcimb.2018.00072] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Accepted: 02/27/2018] [Indexed: 12/20/2022] Open
Abstract
Gram-negative bacteria have evolved numerous two-component systems (TCSs) to cope with external environmental changes. The CpxA/CpxR TCS consisting of the kinase CpxA and the regulator CpxR, is known to be involved in the biofilm formation and virulence of Escherichia coli. However, the role of CpxA/CpxR remained unclear in Actinobacillus pleuropneumoniae, a bacterial pathogen that can cause porcine contagious pleuropneumonia (PCP). In this report, we show that CpxA/CpxR contributes to the biofilm formation ability of A. pleuropneumoniae. Furthermore, we demonstrate that CpxA/CpxR plays an important role in the expression of several biofilm-related genes in A. pleuropneumoniae, such as rpoE and pgaC. Furthermore, The results of electrophoretic mobility shift assays (EMSAs) and DNase I footprinting analysis demonstrate that CpxR-P can regulate the expression of the pgaABCD operon through rpoE. In an experimental infection of mice, the animals infected with a cpxA/cpxR mutant exhibited delayed mortality and lower bacterial loads in the lung than those infected with the wildtype bacteria. In conclusion, these results indicate that the CpxA/CpxR TCS plays a contributing role in the biofilm formation and virulence of A. pleuropneumoniae.
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Affiliation(s)
- Huan Li
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China.,The Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, China.,Key Laboratory of Development of Veterinary Diagnostic Products of Ministry of Agriculture, Huazhong Agricultural University, Wuhan, China
| | - Feng Liu
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China.,The Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, China.,Key Laboratory of Development of Veterinary Diagnostic Products of Ministry of Agriculture, Huazhong Agricultural University, Wuhan, China
| | - Wei Peng
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China.,The Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, China.,Key Laboratory of Development of Veterinary Diagnostic Products of Ministry of Agriculture, Huazhong Agricultural University, Wuhan, China
| | - Kang Yan
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China.,The Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, China.,Key Laboratory of Development of Veterinary Diagnostic Products of Ministry of Agriculture, Huazhong Agricultural University, Wuhan, China
| | - Haixu Zhao
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China.,The Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, China.,Key Laboratory of Development of Veterinary Diagnostic Products of Ministry of Agriculture, Huazhong Agricultural University, Wuhan, China
| | - Ting Liu
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China.,The Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, China.,Key Laboratory of Development of Veterinary Diagnostic Products of Ministry of Agriculture, Huazhong Agricultural University, Wuhan, China
| | - Hui Cheng
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China.,The Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, China.,Key Laboratory of Development of Veterinary Diagnostic Products of Ministry of Agriculture, Huazhong Agricultural University, Wuhan, China
| | - Peixi Chang
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China.,The Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, China.,Key Laboratory of Development of Veterinary Diagnostic Products of Ministry of Agriculture, Huazhong Agricultural University, Wuhan, China
| | - Fangyan Yuan
- Hubei Key Laboratory of Animal Embryo and Molecular Breeding, Institute of Animal Husbandry and Veterinary Sciences, Hubei Academy of Agricultural Sciences, Wuhan, China
| | - Huanchun Chen
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China.,The Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, China.,Key Laboratory of Development of Veterinary Diagnostic Products of Ministry of Agriculture, Huazhong Agricultural University, Wuhan, China
| | - Weicheng Bei
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China.,The Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, China.,Key Laboratory of Development of Veterinary Diagnostic Products of Ministry of Agriculture, Huazhong Agricultural University, Wuhan, China
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8
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Chen L, Li Y, Tian P. Enhanced Promoter Activity by Replenishment of Sigma Factor rpoE in Klebsiella pneumoniae. Indian J Microbiol 2016; 56:190-7. [PMID: 27570311 DOI: 10.1007/s12088-016-0576-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [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: 07/15/2015] [Accepted: 03/24/2016] [Indexed: 11/26/2022] Open
Abstract
Plasmid-dependent overexpression of enzyme(s) aims to divert carbon flux toward a desired compound. One drawback of this strategy is compromise of growth due to massive consumption of host resources. Here we show that replenishment of sigma factor rpoE improves the growth of Klebsiella pneumoniae. The gene rpoE was expressed alone or coexpressed with Ald4 (an aldehyde dehydrogenase from Saccharomyces cerevisiae) in K. pneumoniae. We found that the Ald4 activity was higher in the strain coexpressing Ald4 and rpoE (32.3 U/mg) than that expressing Ald4 alone (29.9 U/mg). Additionally, under shake-flask conditions, the strain coexpressing Ald4 and rpoE produced 0.5 g 3-hydroxypropionic acid (3-HP) and 9.8 g 1,3-propanediol (1,3-PD) per liter in 24 h, which were 1.6- and 0.85-fold enhancement, respectively, compared to those expressing Ald4 alone. Notably, under non-optimized bioreactor conditions, the strain coexpressing Ald4 and rpoE produced 13.5 g 3-HP and 37.8 g 1,3-PD per liter with glycerol conversion ratio of 0.45 mol/mol. These results indicate that replenishment of rpoE enhanced promoter activity and stimulated glycerol consumption.
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Affiliation(s)
- Liuni Chen
- Beijing Key Lab of Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, 100029 People's Republic of China
| | - Ying Li
- Beijing Key Lab of Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, 100029 People's Republic of China
| | - Pingfang Tian
- Beijing Key Lab of Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, 100029 People's Republic of China
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9
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Zhang Q, Zhang Y, Zhang X, Zhan L, Zhao X, Xu S, Sheng X, Huang X. The novel cis-encoded antisense RNA AsrC positively regulates the expression of rpoE-rseABC operon and thus enhances the motility of Salmonella enterica serovar typhi. Front Microbiol 2015; 6:990. [PMID: 26441919 PMCID: PMC4585123 DOI: 10.3389/fmicb.2015.00990] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Accepted: 09/04/2015] [Indexed: 11/13/2022] Open
Abstract
Bacterial non-coding RNAs are essential in many cellular processes, including response to environmental stress, and virulence. Deep sequencing analysis of the Salmonella enterica serovar typhi (S. typhi) transcriptome revealed a novel antisense RNA transcribed in cis on the strand complementary to rseC, an activator gene of sigma factor RpoE. In this study, expression of this antisense RNA was confirmed in S. typhi by Northern hybridization. Rapid amplification of cDNA ends and sequence analysis identified an 893 bp sequence from the antisense RNA coding region that covered all of the rseC coding region in the reverse direction of transcription. This sequence of RNA was named as AsrC. After overexpression of AsrC with recombinantant plasmid in S. typhi, the bacterial motility was increased obviously. To explore the mechanism of AsrC function, regulation of rseC and rpoE expression by AsrC was investigated. We found that AsrC increased the levels of rseC mRNA and protein. The expression of rpoE was also increased in S. typhi after overexpression of AsrC, which was dependent on rseC. Thus, we propose that AsrC increased RseC level and indirectly activating RpoE which can initiate fliA expression and promote the motility of S. typhi.
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Affiliation(s)
- Qi Zhang
- Department of Biochemistry and Molecular Biology, Jiangsu University - School of Medicine Zhenjiang, China ; Danyang People's Hospital of Jiangsu Province Danyang, China
| | - Ying Zhang
- Department of Biochemistry and Molecular Biology, Jiangsu University - School of Medicine Zhenjiang, China
| | - Xiaolei Zhang
- Department of Biochemistry and Molecular Biology, Jiangsu University - School of Medicine Zhenjiang, China
| | - Lifang Zhan
- Department of Biochemistry and Molecular Biology, Jiangsu University - School of Medicine Zhenjiang, China
| | - Xin Zhao
- Department of Biochemistry and Molecular Biology, Jiangsu University - School of Medicine Zhenjiang, China
| | - Shungao Xu
- Department of Biochemistry and Molecular Biology, Jiangsu University - School of Medicine Zhenjiang, China
| | - Xiumei Sheng
- Department of Biochemistry and Molecular Biology, Jiangsu University - School of Medicine Zhenjiang, China
| | - Xinxiang Huang
- Department of Biochemistry and Molecular Biology, Jiangsu University - School of Medicine Zhenjiang, China
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