scholarly journals The quorum sensing system luxS gene contributes to the environmental fitness of Streptococcus suis

2020 ◽  
Author(s):  
Jinpeng Li ◽  
Yuxin Wang ◽  
Yanbin Du ◽  
Hui Zhang ◽  
Qingyin Fan ◽  
...  
Keyword(s):  
Stress Response ◽  
Abc Transporter ◽  
Virulence Gene ◽  
Streptococcus Suis ◽  
Growth Stress ◽  
Growth And Survival ◽  
Virulence Gene Expression ◽  
Overexpression Strain ◽  
Wide Range ◽  
And Oxidative Stress

Abstract Background: Streptococcus suis type 2 (SS2) is an important zoonotic pathogen. We have previously reported the structure of LuxS protein and found that the luxS gene is closely related to biofilm, virulence gene expression and drug resistance of SS2. However, the mechanism of luxS mediated SS2 stress response is unclear. Therefore, this experiment performed stress response to luxS mutant (ΔluxS) and complement strain (CΔluxS), overexpression strain (luxS+) and wild-type SS2 strain HA9801, and analyzed the differential phenotypes in combination with transcriptome data.Results: The results indicate that the luxS gene causes a wide range of phenotypic changes, including chain length. RNA sequencing identified 278 luxS-regulated genes, of which 179 were up-regulated and 99 were down-regulated. Differential genes focus on bacterial growth, stress response, metabolic mechanisms and drug tolerance. Multiple mitotic genes were down-regulated; while the ABC transporter system genes, cobalamin /Fe3+-iron carrier ABC transporter ATPase and oxidative stress regulators were up-regulated. The inactivation of the luxS gene caused a significant reduction in the growth and survival in the acid and iron stress environments. However, the mutant strain ΔluxS showed increased antioxidant activity to H2O2. Conclusions: The luxS gene in SS2 appears to play roles in iron metabolism and protective responses to acidic and oxidative environmental conditions.

scholarly journals mRNA-Seq reveals the quorum sensing system luxS gene contributes to the environmental fitness of Streptococcus suis type 2

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Jinpeng Li ◽  
Yuxin Wang ◽  
Yanbin Du ◽  
Hui Zhang ◽  
Qingying Fan ◽  
...  
Keyword(s):  
Stress Response ◽  
Abc Transporter ◽  
Virulence Gene ◽  
Streptococcus Suis ◽  
Iron Chelator ◽  
Growth Stress ◽  
Growth And Survival ◽  
Virulence Gene Expression ◽  
Overexpression Strain ◽  
Wide Range

Abstract Background Streptococcus suis type 2 (SS2) is an important zoonotic pathogen. We have previously reported the structure of LuxS protein and found that the luxS gene is closely related to biofilm, virulence gene expression and drug resistance of SS2. However, the mechanism of luxS mediated SS2 stress response is unclear. Therefore, this experiment performed stress response to luxS mutant (ΔluxS) and complement strain (CΔluxS), overexpression strain (luxS+) and wild-type SS2 strain HA9801, and analyzed the differential phenotypes in combination with transcriptome data. Results The results indicate that the luxS gene deletion causes a wide range of phenotypic changes, including chain length. RNA sequencing identified 278 lx-regulated genes, of which 179 were up-regulated and 99 were down-regulated. Differential genes focus on bacterial growth, stress response, metabolic mechanisms and drug tolerance. Multiple mitotic genes were down-regulated; while the ABC transporter system genes, cobalamin /Fe3+-iron carrier ABC transporter ATPase and oxidative stress regulators were up-regulated. The inactivation of the luxS gene caused a significant reduction in the growth and survival in the acid (pH = 3.0, 4.0, 5.0) and iron (100 mM iron chelator 2,2′-dipyridyl) stress environments. However, the mutant strain ΔluxS showed increased antioxidant activity to H2O2 (58.8 mmol/L). Conclusions The luxS gene in SS2 appears to play roles in iron metabolism and protective responses to acidic and oxidative environmental conditions.

Norfloxacin Sub-Inhibitory Concentration Affects Streptococcus suis Biofilm Formation and Virulence Gene Expression

2020 ◽  
Author(s):  
Baobao Li ◽  
Li Yi ◽  
Jinpeng Li ◽  
Shenglong Gong ◽  
Xiao Dong ◽  
...  
Keyword(s):  
Gene Expression ◽  
Biofilm Formation ◽  
Inhibitory Concentration ◽  
Mrna Level ◽  
Virulence Gene ◽  
Streptococcus Suis ◽  
Economic Losses ◽  
Swine Industry ◽  
Virulence Gene Expression ◽  
Viable Bacteria

Streptococcus suis (S. suis) is a major pathogen causing economic losses to the swine industry. Norfloxacins are usually used at sub-MIC (Minimum Inhibitory Concentration) doses to prevent S. suis infection. This study demonstrates the effect of norfloxacin sub-MIC on biofilm formation and virulence gene expression in S. suis.It was found that 1/4 MIC of norfloxacin increased biofilm formation in S. suis, the biofilms formed contained a higher number of viable bacteria. Additionally, bacterial growth rates were inhibited at 1/2 MIC of norfloxacin. Furthermore, the mRNA level of S. suis virulence gene cps, ef, sly, fpbs, gdh and gapdh increased by real-time PCR, while the virulence gene mrp decreased at 1/4 MIC. In conclusion, Norfloxacin sub-MICs affects biofilm formation and virulence gene expression in S. suis. These findings suggest that investigating the effect of the administration of antibiotics sub-MICs on bacterial biofilms and infection may lead to the development of future antibiotic treatments modalities.

scholarly journals Listeria monocytogenes σB Regulates Stress Response and Virulence Functions

2003 ◽  
Vol 185 (19) ◽  
pp. 5722-5734 ◽  
Author(s):  
Mark J. Kazmierczak ◽  
Sharon C. Mithoe ◽  
Kathryn J. Boor ◽  
Martin Wiedmann
Keyword(s):  
Gene Expression ◽  
Listeria Monocytogenes ◽  
Stress Response ◽  
Consensus Sequence ◽  
Virulence Gene ◽  
Wild Type ◽  
Promoter Regions ◽  
Virulence Gene Expression ◽  
Stress Response Genes ◽  
In The Wild

ABSTRACT While the stress-responsive alternative sigma factor σB has been identified in different species of Bacillus, Listeria, and Staphylococcus, theσ B regulon has been extensively characterized only in B. subtilis. We combined biocomputing and microarray-based strategies to identify σB-dependent genes in the facultative intracellular pathogen Listeria monocytogenes. Hidden Markov model (HMM)-based searches identified 170 candidateσ B-dependent promoter sequences in the strain EGD-e genome sequence. These data were used to develop a specialized, 208-gene microarray, which included 166 genes downstream of HMM-predicted σB-dependent promoters as well as selected virulence and stress response genes. RNA for the microarray experiments was isolated from both wild-type and ΔsigB null mutant L. monocytogenes cells grown to stationary phase or exposed to osmotic stress (0.5 M KCl). Microarray analyses identified a total of 55 genes with statistically significantσ B-dependent expression under the conditions used in these experiments, with at least 1.5-fold-higher expression in the wild type over the sigB mutant under either stress condition (51 genes showed at least 2.0-fold-higher expression in the wild type). Of the 55 genes exhibiting σB-dependent expression, 54 were preceded by a sequence resembling the σB promoter consensus sequence. Rapid amplification of cDNA ends-PCR was used to confirm the σB-dependent nature of a subset of eight selected promoter regions. Notably, theσ B-dependent L. monocytogenes genes identified through this HMM/microarray strategy included both stress response genes (e.g., gadB, ctc, and the glutathione reductase gene lmo1433) and virulence genes (e.g., inlA, inlB, and bsh). Our data demonstrate that, in addition to regulating expression of genes important for survival under environmental stress conditions, σB also contributes to regulation of virulence gene expression in L. monocytogenes. These findings strongly suggest thatσ B contributes to L. monocytogenes gene expression during infection.

scholarly journals Carbohydrate Availability Regulates Virulence Gene Expression in Streptococcus suis

PLoS ONE ◽  
2014 ◽  
Vol 9 (3) ◽  
pp. e89334 ◽  
Author(s):  
M. Laura Ferrando ◽  
Peter van Baarlen ◽  
Germano Orrù ◽  
Rosaria Piga ◽  
Roger S. Bongers ◽  
...  
Keyword(s):  
Gene Expression ◽  
Virulence Gene ◽  
Streptococcus Suis ◽  
Virulence Gene Expression ◽  
Carbohydrate Availability

scholarly journals NF-κB signaling pathway and free radical impact.

2012 ◽  
Vol 59 (3) ◽  
Author(s):  
Agnieszka Siomek
Keyword(s):  
Oxidative Stress ◽  
Transcription Factor ◽  
Free Radicals ◽  
Free Radical ◽  
Ionizing Radiation ◽  
Physiological Role ◽  
Growth And Survival ◽  
Wide Range ◽  
The Impact ◽  
And Oxidative Stress

The activation of NF-κB transcription factor is critical for a wide range of processes such as immunity, inflammation, cell development, growth and survival. It is activated by a variety of stimuli including cytokines, ionizing radiation and oxidative stress. Redox modulations of NF-κB pathway have been widely demonstrated. Studies carried out during last years have advanced our knowledge about possible connections between NF-κB pathway and the impact of free radicals. This review is an endeavor to gather recent results focused on this issue, although an important question, whether oxidative stress plays a physiological role in NF-κB activation, seems to be still unanswered.

scholarly journals Role for sagA and siaA in Quorum Sensing and Iron Regulation in Streptococcus pyogenes

2007 ◽  
Vol 75 (10) ◽  
pp. 5011-5017 ◽  
Author(s):  
Kowthar Y. Salim ◽  
Joyce C. de Azavedo ◽  
Darrin J. Bast ◽  
Dennis G. Cvitkovitch
Keyword(s):  
Quorum Sensing ◽  
Streptococcus Pyogenes ◽  
Iron Acquisition ◽  
Virulence Gene ◽  
Wild Type ◽  
Virulence Gene Expression ◽  
Streptolysin S ◽  
Wide Range ◽  
Cell Densities ◽  
The Many

ABSTRACT Streptococcus pyogenes is a ubiquitous and versatile pathogen that causes a variety of infections with a wide range of severity. The versatility of this organism is due in part to its capacity to regulate virulence gene expression in response to the many environments that it encounters during an infection. We analyzed the expression of two potential virulence factors, sagA and siaA (also referred to as pel and htsA, respectively), in response to conditions of varying cell densities and iron concentrations. The sagA gene was up-regulated in conditioned medium from a wild-type strain but not from sagA-deficient mutants, and the gene was also up-regulated in the presence of streptolysin S (SLS), the gene product of sagA, thus indicating that this gene or its product is involved in density-dependent regulation of S. pyogenes. By comparison, siaA responded in a manner consistent with a role in iron acquisition since it was up-regulated under iron-restricted conditions. Although siaA expression was also up-regulated in the presence of SLS and in conditioned media from both wild-type and sagA-deficient mutants, this up-regulation was not growth phase dependent. We conclude that sagA encodes a quorum-sensing signaling molecule, likely SLS, and further support the notion that siaA is likely involved in iron acquisition.

scholarly journals The Tzs Protein and Exogenous Cytokinin Affect Virulence Gene Expression and Bacterial Growth of Agrobacterium tumefaciens

2013 ◽  
Vol 103 (9) ◽  
pp. 888-899 ◽  
Author(s):  
Hau-Hsuan Hwang ◽  
Fong-Jhih Yang ◽  
Tun-Fang Cheng ◽  
Yi-Chun Chen ◽  
Ying-Ling Lee ◽  
...  
Keyword(s):  
Gene Expression ◽  
Agrobacterium Tumefaciens ◽  
Bacterial Growth ◽  
Deletion Mutant ◽  
Virulence Gene ◽  
Protein Accumulation ◽  
Virulence Gene Expression ◽  
Crown Gall Disease ◽  
Wide Range ◽  
Exogenous Cytokinin

The soil phytopathogen Agrobacterium tumefaciens causes crown gall disease in a wide range of plant species. The neoplastic growth at the infection sites is caused by transferring, integrating, and expressing transfer DNA (T-DNA) from A. tumefaciens into plant cells. A trans-zeatin synthesizing (tzs) gene is located in the nopaline-type tumor-inducing plasmid and causes trans-zeatin production in A. tumefaciens. Similar to known virulence (Vir) proteins that are induced by the vir gene inducer acetosyringone (AS) at acidic pH 5.5, Tzs protein is highly induced by AS under this growth condition but also constitutively expressed and moderately upregulated by AS at neutral pH 7.0. We found that the promoter activities and protein levels of several AS-induced vir genes increased in the tzs deletion mutant, a mutant with decreased tumorigenesis and transient transformation efficiencies, in Arabidopsis roots. During AS induction and infection of Arabidopsis roots, the tzs deletion mutant conferred impaired growth, which could be rescued by genetic complementation and supplementing exogenous cytokinin. Exogenous cytokinin also repressed vir promoter activities and Vir protein accumulation in both the wild-type and tzs mutant bacteria with AS induction. Thus, the tzs gene or its product, cytokinin, may be involved in regulating AS-induced vir gene expression and, therefore, affect bacterial growth and virulence during A. tumefaciens infection.

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