scholarly journals A novel PilR/PilS two-component system regulates NE pilus production in Clostridium perfringens

2021 ◽  
Author(s):  
Yuanyuan Zhou ◽  
Dion Lepp ◽  
Jason Carere ◽  
Hai Yu ◽  
Chengbo Yang ◽  
...  
Keyword(s):  
Quorum Sensing ◽  
Clostridium Perfringens ◽  
Binding Activity ◽  
Necrotic Enteritis ◽  
Wild Type ◽  
Two Component System ◽  
Collagen Binding ◽  
Component System ◽  
Two Component

Clostridium perfringens causes necrotic enteritis (NE) in poultry. A chromosomal locus (VR-10B) was previously identified in NE-causing C. perfringens strains that encodes an adhesive pilus (NE pilus), along with a two-component system (TCS), designated here as PilRS. While the NE pilus is important in pathogenesis, the role of PilRS remains to be determined. The current study investigated the function of PilRS, as well as the Agr-like quorum-sensing (QS) system and VirSR TCS, in the regulation of pilin production. Isogenic pilR , agrB and virR null mutants were generated from parent strain CP1 by insertional inactivation using the ClosTron system, along with the respective complemented strains. Immunoblotting analyses showed no detectable pilus production in the CP1 pilR mutant, while production in its complement (CP1 pilR +) was greater than wild-type levels. In contrast, pilus production in the agrB and virR mutants was comparable or higher than the wild type, but reduced in their respective complemented strains. When examined for collagen-binding activity, the pilR mutant showed significantly lower binding to most collagen types (types I – V) than CP1 ( p ≤ 0.05), whereas this activity was restored in the complemented strain ( p > 0.05). In contrast, binding of agrB and virR mutants to collagen showed no significant differences in collagen-binding activity compared to CP1 ( p > 0.05), whereas the complemented strains exhibited significantly reduced binding ( p ≤ 0.05). These data suggest that the PilRS TCS positively regulates pilus production in C. perfringens , while the Agr-like QS system may serve as a negative regulator of this operon. Importance Clostridium perfringens type G isolates cause necrotic enteritis (NE) in poultry, presenting a major challenge for poultry production in the post-antibiotic era. Multiple factors in C. perfringens , including both virulent and non-virulent, are involved in the development of the disease. We previously discovered a cluster of C. perfringens genes that encode a pilus involved in adherence and NE development and a predicted two-component regulatory system (TCS), designated PilRS. In the present study, we have demonstrated the role of PilRS in regulating pilus production and collagen binding of C. perfringens . In addition, the Agr-like quorum sensing signalling pathway was found to be involved in the regulation. These findings have identified additional targets for developing non-antibiotic strategies to control NE disease.

The role of PhoP/PhoQ two component system in regulating stress adaptation in Cronobacter sakazakii

2021 ◽  
pp. 103851
Author(s):  
Yan Ma ◽  
Yingying Zhang ◽  
Ke Chen ◽  
Lingzhu Zhang ◽  
Yibei Zhang ◽  
...  
Keyword(s):  
Stress Adaptation ◽  
Cronobacter Sakazakii ◽  
Two Component System ◽  
Component System ◽  
Two Component

scholarly journals Regulatory Role of the MisR/S Two-Component System in Hemoglobin Utilization in Neisseria meningitidis

2009 ◽  
Vol 78 (3) ◽  
pp. 1109-1122 ◽  
Author(s):  
Shuming Zhao ◽  
Grisselle E. Montanez ◽  
Pradeep Kumar ◽  
Soma Sannigrahi ◽  
Yih-Ling Tzeng
Keyword(s):  
Posttranscriptional Regulation ◽  
Regulatory Mechanisms ◽  
Two Component System ◽  
Gene Encoding ◽  
Positive Role ◽  
Upstream Gene ◽  
Component System ◽  
Two Component ◽  
Major Surface

ABSTRACT Outer membrane iron receptors are some of the major surface entities that are critical for meningococcal pathogenesis. The gene encoding the meningococcal hemoglobin receptor, HmbR, is both independently transcribed and transcriptionally linked to the upstream gene hemO, which encodes a heme oxygenase. The MisR/S two-component system was previously determined to regulate hmbR transcription, and its hemO and hmbR regulatory mechanisms were characterized further here. The expression of hemO and hmbR was downregulated in misR/S mutants under both iron-replete and iron-restricted conditions, and the downregulation could be reversed by complementation. No significant changes in expression of other iron receptors were detected, suggesting that the MisR/S system specifically regulates hmbR. When hemoglobin was the sole iron source, growth defects were detected in the mutants. Primer extension analysis identified a promoter upstream of the hemO-associated Correia element (CE) and another promoter at the proximal end of CE, and processed transcripts previously identified for other cotranscribed CEs were also detected, suggesting that there may be posttranscriptional regulation. MisR directly interacts with sequences upstream of the CE and upstream of the hmbR Fur binding site and thus independently regulates hemO and hmbR. Analysis of transcriptional reporters of hemO and hmbR further demonstrated the positive role of the MisR/S system and showed that the transcription of hmbR initiated from hemO was significantly reduced. A comparison of the effects of the misS mutation under iron-replete and iron-depleted conditions suggested that activation by the MisR/S system and iron-mediated repression by Fur act independently. Thus, the expression of hemO and hmbR is coordinately controlled by multiple independent regulatory mechanisms, including the MisR/S two-component system.

scholarly journals The Staphylococcus aureus KdpDE Two-Component System Couples Extracellular K+Sensing and Agr Signaling to Infection Programming

2011 ◽  
Vol 79 (6) ◽  
pp. 2154-2167 ◽  
Author(s):  
Ting Xue ◽  
Yibo You ◽  
De Hong ◽  
Haipeng Sun ◽  
Baolin Sun
Keyword(s):  
Staphylococcus Aureus ◽  
Uptake System ◽  
Main Function ◽  
Two Component System ◽  
Component System ◽  
Content Type ◽  
Two Component ◽  
Virulence Regulator ◽  
External K

ABSTRACTThe Kdp system is widely distributed among bacteria. InEscherichia coli, the Kdp-ATPase is a high-affinity K+uptake system and its expression is activated by the KdpDE two-component system in response to K+limitation or salt stress. However, information about the role of this system in many bacteria still remains obscure. Here we demonstrate that KdpFABC inStaphylococcus aureusis not a major K+transporter and that the main function of KdpDE is not associated with K+transport but that instead it regulates transcription for a series of virulence factors through sensing external K+concentrations, indicating that this bacterium might modulate its infectious status through sensing specific external K+stimuli in different environments. Our results further reveal thatS. aureusKdpDE is upregulated by the Agr/RNAIII system, which suggests that KdpDE may be an important virulence regulator coordinating the external K+sensing and Agr signaling during pathogenesis in this bacterium.

scholarly journals The CasKR Two-Component System Is Required for the Growth of Mesophilic and Psychrotolerant Bacillus cereus Strains at Low Temperatures

2014 ◽  
Vol 80 (8) ◽  
pp. 2493-2503 ◽  
Author(s):  
Sara Esther Diomandé ◽  
Stéphanie Chamot ◽  
Vera Antolinos ◽  
Florian Vasai ◽  
Marie-Hélène Guinebretière ◽  
...  
Keyword(s):  
Bacillus Cereus ◽  
Food Poisoning ◽  
Two Component System ◽  
Diverse Range ◽  
Component System ◽  
Content Type ◽  
Two Component ◽  
Temperature Ranges ◽  
Different Strains

ABSTRACTThe different strains ofBacillus cereuscan grow at temperatures covering a very diverse range. SomeB. cereusstrains can grow in chilled food and consequently cause food poisoning. We have identified a new sensor/regulator mechanism involved in low-temperatureB. cereusgrowth. Construction of a mutant of this two-component system enabled us to show that this system, called CasKR, is required for growth at the minimal temperature (Tmin). CasKR was also involved in optimal cold growth aboveTminand in cell survival belowTmin. Microscopic observation showed that CasKR plays a key role in cell shape during cold growth. Introducing thecasKRgenes in a ΔcasKRmutant restored its ability to grow atTmin. Although it was first identified in the ATCC 14579 model strain, this mechanism has been conserved in most strains of theB. cereusgroup. We show that the role of CasKR in cold growth is similar in otherB. cereus sensu latostrains with different growth temperature ranges, including psychrotolerant strains.

scholarly journals A novel two-component system modulates quorum sensing and pathogenicity inBurkholderia cenocepacia

2018 ◽  
Vol 108 (1) ◽  
pp. 32-44 ◽  
Author(s):  
Chaoyu Cui ◽  
Chunxi Yang ◽  
Shihao Song ◽  
Shuna Fu ◽  
Xiuyun Sun ◽  
...  
Keyword(s):  
Quorum Sensing ◽  
Two Component System ◽  
Component System ◽  
Two Component

scholarly journals Autoinducer-2 and QseC Control Biofilm Formation and In Vivo Virulence of Aggregatibacter actinomycetemcomitans

2010 ◽  
Vol 78 (7) ◽  
pp. 2919-2926 ◽  
Author(s):  
Elizabeth A. Novak ◽  
HanJuan Shao ◽  
Carlo Amorin Daep ◽  
Donald R. Demuth
Keyword(s):  
Bone Resorption ◽  
Bone Loss ◽  
Biofilm Formation ◽  
Alveolar Bone ◽  
Wild Type ◽  
Two Component System ◽  
Component System ◽  
Autoinducer 2 ◽  
Two Component

ABSTRACT Biofilm formation by the periodontal pathogen Aggregatibacter actinomycetemcomitans is dependent upon autoinducer-2 (AI-2)-mediated quorum sensing. However, the components that link the detection of the AI-2 signal to downstream gene expression have not been determined. One potential regulator is the QseBC two-component system, which is part of the AI-2-dependent response pathway that controls biofilm formation in Escherichia coli. Here we show that the expression of QseBC in A. actinomycetemcomitans is induced by AI-2 and that induction requires the AI-2 receptors, LsrB and/or RbsB. Additionally, inactivation of qseC resulted in reduced biofilm growth. Since the ability to grow in biofilms is essential for A. actinomycetemcomitans virulence, strains that were deficient in QseC or the AI-2 receptors were examined in an in vivo mouse model of periodontitis. The ΔqseC mutant induced significantly less alveolar bone resorption than the wild-type strain (P < 0.02). Bone loss in animals infected with the ΔqseC strain was similar to that in sham-infected animals. The ΔlsrB, ΔrbsB, and ΔlsrB ΔrbsB strains also induced significantly less alveolar bone resorption than the wild type (P < 0.03, P < 0.02, and P < 0.01, respectively). However, bone loss induced by a ΔluxS strain was indistinguishable from that induced by the wild type, suggesting that AI-2 produced by indigenous microflora in the murine oral cavity may complement the ΔluxS mutation. Together, these results suggest that the QseBC two-component system is part of the AI-2 regulon and may link the detection of AI-2 to the regulation of downstream cellular processes that are involved in biofilm formation and virulence of A. actinomycetemcomitans.

scholarly journals Site-Directed Mutagenesis Identifies a Molecular Switch Involved in Copper Sensing by the Histidine Kinase CinS in Pseudomonas putida KT2440

2009 ◽  
Vol 191 (16) ◽  
pp. 5304-5311 ◽  
Author(s):  
Davide Quaranta ◽  
Megan M. McEvoy ◽  
Christopher Rensing
Keyword(s):  
Pseudomonas Putida ◽  
Histidine Kinase ◽  
Site Directed Mutagenesis ◽  
Directed Mutagenesis ◽  
Copper Binding ◽  
Wild Type ◽  
Two Component System ◽  
Pseudomonas Putida Kt2440 ◽  
Component System ◽  
Two Component

ABSTRACT In the presence of copper, Pseudomonas putida activates transcription of cinAQ via the two-component system CinS-CinR. The CinS-CinR TCS was responsive to 0.5 μM copper and was specifically activated only by copper and silver. Modeling studies of CinS identified a potential copper binding site containing H37 and H147. CinS mutants with H37R and H147R mutations had an almost 10-fold reduced copper-dependent induction of cinAQ compared to the wild type.

scholarly journals The Agr-Like Quorum Sensing System Is Required for Pathogenesis of Necrotic Enteritis Caused by Clostridium perfringens in Poultry

2017 ◽  
Vol 85 (6) ◽  
Author(s):  
Qiang Yu ◽  
Dion Lepp ◽  
Iman Mehdizadeh Gohari ◽  
Tao Wu ◽  
Hongzhuan Zhou ◽  
...  
Keyword(s):  
Quorum Sensing ◽  
Clostridium Perfringens ◽  
Global Gene Expression ◽  
Toxin Production ◽  
Phospholipid Metabolism ◽  
Necrotic Enteritis ◽  
Content Type ◽  
Protein Levels ◽  
Global Gene Expression Analysis

ABSTRACT Clostridium perfringens encodes at least two different quorum sensing (QS) systems, the Agr-like and LuxS, and recent studies have highlighted their importance in the regulation of toxin production and virulence. The role of QS in the pathogenesis of necrotic enteritis (NE) in poultry and the regulation of NetB, the key toxin involved, has not yet been investigated. We have generated isogenic agrB-null and complemented strains from parent strain CP1 and demonstrated that the virulence of the agrB-null mutant was strongly attenuated in a chicken NE model system and restored by complementation. The production of NetB, a key NE-associated toxin, was dramatically reduced in the agrB mutant at both the transcriptional and protein levels, though not in a luxS mutant. Transwell assays confirmed that the Agr-like QS system controls NetB production through a diffusible signal. Global gene expression analysis of the agrB mutant identified additional genes modulated by Agr-like QS, including operons related to phospholipid metabolism and adherence, which may also play a role in NE pathogenesis. This study provides the first evidence that the Agr-like QS system is critical for NE pathogenesis and identifies a number of Agr-regulated genes, most notably netB, that are potentially involved in mediating its effects. The Agr-like QS system thus may serve as a target for developing novel interventions to prevent NE in chickens.

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