scholarly journals The BvgS PAS domain: an independent sensory perception module in theBordetellaBvgAS phosphorelay

2019 ◽  
Author(s):  
M. Ashley Sobran ◽  
Peggy A. Cotter
Keyword(s):  
Respiratory Tract ◽  
Bordetella Pertussis ◽  
Kinase Activity ◽  
Expression Patterns ◽  
Pas Domain ◽  
Human Respiratory Tract ◽  
Signal Perception ◽  
Two Component

AbstractTo detect and respond to the diverse environments they encounter, bacteria often use two-component regulatory systems (TCSs) to coordinate essential cellular processes required for survival. In pathogenicBordetellaspecies, the BvgAS TCS regulates expression of hundreds of genes, including those encoding all known protein virulence factors, and its kinase activity is essential for respiratory infection. Maintenance of BvgS kinase activity in the lower respiratory tract (LRT) depends on the function of another TCS, PlrSR. While the periplasmic venus fly-trap domains of BvgS have been implicated in responding to so-called modulating signalsin vitro(nicotinic acid and MgSO4), a role for the cytoplasmic Per-Arnt-Sim (PAS) domain in signal perception has not previously been demonstrated. By comparingB. bronchisepticastrains with mutations in the PAS domain-encoding region ofbvgSwith wild-type bacteriain vitroandin vivo, we found that although the PAS domain is not required to sense modulating signalsin vitro, it is required for the inactivation of BvgS that occurs in the absence of PlrS in the LRT of mice, suggesting that the BvgS PAS domain functions as an independent signal perception domain. Our data also indicate that the BvgS PAS domain is important for controlling absolute levels of BvgS kinase activity and the efficiency of the response to modulating signalsin vitro. Our results indicate that BvgS is capable of integrating sensory inputs from both the periplasm and the cytoplasm to control precise gene expression patterns in diverse environmental conditions.ImportanceDespite high rates of vaccination, Pertussis, a severe, highly contagious respiratory disease, caused by the bacteriumBordetella pertussis, has reemerged as a significant health threat. InBordetella pertussisand the closely related species,Bordetella bronchiseptica, activity of the BvgAS two-component regulatory system is critical for colonization of the human respiratory tract and other mammalian hosts, respectively. Here we show that the cytoplasmic PAS domain of BvgS can function as an independent signal perception domain that is capable of integrating environmental signals that influence overall BvgS activity. Our work is significant as it reveals a critical, yet previously unrecognized role, for the PAS domain in the BvgAS phosphorelay and provides a greater understanding of virulence regulation inBordetella.

scholarly journals The BvgS PAS Domain, an Independent Sensory Perception Module in theBordetella bronchisepticaBvgAS Phosphorelay

2019 ◽  
Vol 201 (17) ◽  
Author(s):  
M. Ashley Sobran ◽  
Peggy A. Cotter
Keyword(s):  
Respiratory Tract ◽  
Bordetella Pertussis ◽  
Environmental Conditions ◽  
Kinase Activity ◽  
Expression Patterns ◽  
Pas Domain ◽  
Content Type ◽  
Signal Perception ◽  
Two Component

ABSTRACTTo detect and respond to the diverse environments they encounter, bacteria often use two-component regulatory systems (TCS) to coordinate essential cellular processes required for survival. In pathogenicBordetellaspecies, the BvgAS TCS regulates expression of hundreds of genes, including those encoding all known protein virulence factors, and its kinase activity is essential for respiratory infection. Maintenance of BvgS kinase activity in the lower respiratory tract (LRT) depends on the function of another TCS, PlrSR. While the periplasmic Venus flytrap domains of BvgS have been implicated in responding to so-called modulating signalsin vitro(nicotinic acid and MgSO4), a role for the cytoplasmic Per-Arnt-Sim (PAS) domain in signal perception has not previously been demonstrated. By comparingB. bronchisepticastrains with mutations in the PAS domain-encoding region ofbvgSwith wild-type bacteriain vitroandin vivo, we found that although the PAS domain is not required to sense modulating signalsin vitro, it is required for the inactivation of BvgS that occurs in the absence of PlrS in the LRTs of mice, suggesting that the BvgS PAS domain functions as an independent signal perception domain. Our data also indicate that the BvgS PAS domain is important for controlling absolute levels of BvgS kinase activity and the efficiency of the response to modulating signalsin vitro. Our results provide evidence that BvgS integrates sensory inputs from both the periplasm and the cytoplasm to control precise gene expression patterns under diverse environmental conditions.IMPORTANCEDespite high rates of vaccination, pertussis, a severe, highly contagious respiratory disease caused by the bacteriumBordetella pertussis, has reemerged as a significant health threat. InBordetella pertussisand the closely related speciesBordetella bronchiseptica, activity of the BvgAS two-component regulatory system is critical for colonization of the mammalian respiratory tract. We show here that the cytoplasmic PAS domain of BvgS can function as an independent signal perception domain that influences BvgS activity in response to environmental conditions. Our work is significant because it reveals a critical, yet previously unrecognized, role for the PAS domain in the BvgAS phosphorelay and provides a greater understanding of virulence regulation inBordetella.

scholarly journals Prediction of Aerosol Deposition in the Human Respiratory Tract via Computational Models: A Review with Recent Updates

Atmosphere ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 137 ◽  
Author(s):  
Vu Khac Hoang Bui ◽  
Ju-Young Moon ◽  
Minhe Chae ◽  
Duckshin Park ◽  
Young-Chul Lee
Keyword(s):  
Respiratory Tract ◽  
Particle Deposition ◽  
Computational Models ◽  
Aerosol Particles ◽  
Three Dimensional ◽  
Aerosol Deposition ◽  
Research Area ◽  
Human Respiratory Tract

The measurement of deposited aerosol particles in the respiratory tract via in vivo and in vitro approaches is difficult due to those approaches’ many limitations. In order to overcome these obstacles, different computational models have been developed to predict the deposition of aerosol particles inside the lung. Recently, some remarkable models have been developed based on conventional semi-empirical models, one-dimensional whole-lung models, three-dimensional computational fluid dynamics models, and artificial neural networks for the prediction of aerosol-particle deposition with a high accuracy relative to experimental data. However, these models still have some disadvantages that should be overcome shortly. In this paper, we take a closer look at the current research trends as well as the future directions of this research area.

scholarly journals Plasticity of fimbrial genotype and serotype within populations of Bordetella pertussis: analysis by paired flow cytometry and genome sequencing

Microbiology ◽  
2014 ◽  
Vol 160 (9) ◽  
pp. 2030-2044 ◽  
Author(s):  
Thomas E. Vaughan ◽  
Catherine B. Pratt ◽  
Katie Sealey ◽  
Andrew Preston ◽  
Norman K. Fry ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Genome Sequencing ◽  
Bordetella Pertussis ◽  
World Health ◽  
Human Respiratory Tract ◽  
Dna Elements ◽  
Health Organization ◽  
Culture Variability

The fimbriae of Bordetella pertussis are required for colonization of the human respiratory tract. Two serologically distinct fimbrial subunits, Fim2 and Fim3, considered important vaccine components for many years, are included in the Sanofi Pasteur 5-component acellular pertussis vaccine, and the World Health Organization recommends the inclusion of strains expressing both fimbrial serotypes in whole-cell pertussis vaccines. Each of the fimbrial major subunit genes, fim2, fim3, and fimX, has a promoter poly(C) tract upstream of its −10 box. Such monotonic DNA elements are susceptible to changes in length via slipped-strand mispairing in vitro and in vivo, which potentially causes on/off switching of genes at every cell division. Here, we have described intra-culture variability in poly(C) tract lengths and the resulting fimbrial phenotypes in 22 recent UK B. pertussis isolates. Owing to the highly plastic nature of fimbrial promoters, we used the same cultures for both genome sequencing and flow cytometry. Individual cultures of B. pertussis contained multiple fimbrial serotypes and multiple different fimbrial promoter poly(C) tract lengths, which supports earlier serological evidence that B. pertussis expresses both serotypes during infection.

scholarly journals Effects of Psa and F1 on the Adhesive and Invasive Interactions of Yersinia pestis with Human Respiratory Tract Epithelial Cells

2006 ◽  
Vol 74 (10) ◽  
pp. 5636-5644 ◽  
Author(s):  
Fengzhi Liu ◽  
Huaiqing Chen ◽  
Estela M. Galván ◽  
Melissa A. Lasaro ◽  
Dieter M. Schifferli
Keyword(s):  
Epithelial Cells ◽  
Respiratory Tract ◽  
Yersinia Pestis ◽  
Bacterial Adhesion ◽  
Wild Type Strain ◽  
Cell Types ◽  
Human Respiratory Tract ◽  
Bacterial Uptake

ABSTRACT Yersinia pestis, the causative agent of plague, expresses the Psa fimbriae (pH 6 antigen) in vitro and in vivo. To evaluate the potential virulence properties of Psa for pneumonic plague, an Escherichia coli strain expressing Psa was engineered and shown to adhere to three types of human respiratory tract epithelial cells. Psa binding specificity was confirmed with Psa-coated polystyrene beads and by inhibition assays. Individual Y. pestis cells were found to be able to express the capsular antigen fraction 1 (F1) concomitantly with Psa on their surface when analyzed by flow cytometry. To better evaluate the separate effects of F1 and Psa on the adhesive and invasive properties of Y. pestis, isogenic Δcaf (F1 genes), Δpsa, and Δcaf Δpsa mutants were constructed and studied with the three respiratory tract epithelial cells. The Δpsa mutant bound significantly less to all three epithelial cells compared to the parental wild-type strain and the Δcaf and Δcaf Δpsa mutants, indicating that Psa acts as an adhesin for respiratory tract epithelial cells. An antiadhesive effect of F1 was clearly detectable only in the absence of Psa, underlining the dominance of the Psa+ phenotype. Both F1 and Psa inhibited the intracellular uptake of Y. pestis. Thus, F1 inhibits bacterial uptake by inhibiting bacterial adhesion to epithelial cells, whereas Psa seems to block bacterial uptake by interacting with a host receptor that doesn't direct internalization. The Δcaf Δpsa double mutant bound and invaded all three epithelial cell types well, revealing the presence of an undefined adhesin(s) and invasin(s).

scholarly journals The ChrSA and HrrSA Two-Component Systems Are Required for Transcriptional Regulation of thehemAPromoter in Corynebacterium diphtheriae

2016 ◽  
Vol 198 (18) ◽  
pp. 2419-2430 ◽  
Author(s):  
Jonathan M. Burgos ◽  
Michael P. Schmitt
Keyword(s):  
Signal Transduction ◽  
Kinase Activity ◽  
Content Type ◽  
Component Systems ◽  
Two Component ◽  
Two Component Signal Transduction ◽  
Two Component Systems ◽  
Signal Transduction Systems

ABSTRACTCorynebacterium diphtheriaeutilizes heme and hemoglobin (Hb) as iron sources for growth in low-iron environments. InC. diphtheriae, the two-component signal transduction systems (TCSs) ChrSA and HrrSA are responsive to Hb levels and regulate the transcription of promoters forhmuO,hrtAB, andhemA. ChrSA and HrrSA activate transcription at thehmuOpromoter and repress transcription athemAin an Hb-dependent manner. In this study, we show that HrrSA is the predominant repressor athemAand that its activity results in transcriptional repression in the presence and absence of Hb, whereas repression ofhemAby ChrSA is primarily responsive to Hb. DNA binding studies showed that both ChrA and HrrA bind to thehemApromoter region at virtually identical sequences. ChrA binding was enhanced by phosphorylation, while binding to DNA by HrrA was independent of its phosphorylation state. ChrA and HrrA are phosphorylatedin vitroby the sensor kinase ChrS, whereas no kinase activity was observed with HrrSin vitro. Phosphorylated ChrA was not observedin vivo, even in the presence of Hb, which is likely due to the instability of the phosphate moiety on ChrA. However, phosphorylation of HrrA was observedin vivoregardless of the presence of the Hb inducer, and genetic analysis indicates that ChrS is responsible for most of the phosphorylation of HrrAin vivo. Phosphorylation studies strongly suggest that HrrS functions primarily as a phosphatase and has only minimal kinase activity. These findings collectively show a complex mechanism of regulation at thehemApromoter, where both two-component systems act in concert to optimize expression of heme biosynthetic enzymes.IMPORTANCEUnderstanding the mechanism by which two-component signal transduction systems function to respond to environmental stimuli is critical to the study of bacterial pathogenesis. The current study expands on the previous analyses of the ChrSA and HrrSA TCSs in the human pathogenC. diphtheriae. The findings here underscore the complex interactions between the ChrSA and HrrSA systems in the regulation of thehemApromoter and demonstrate how the two systems complement one another to refine and control transcription in the presence and absence of Hb.

scholarly journals Bordetella pertussis Acquires Resistance to Complement-Mediated Killing In Vivo

2003 ◽  
Vol 71 (9) ◽  
pp. 4936-4942 ◽  
Author(s):  
Elizabeth J. Pishko ◽  
David J. Betting ◽  
Christina S. Hutter ◽  
Eric T. Harvill
Keyword(s):  
Respiratory Tract ◽  
Bordetella Pertussis ◽  
Alternative Pathway ◽  
Growth Conditions ◽  
Closely Related Species ◽  
O Antigen ◽  
Complement Resistance ◽  
Alternate Mechanism

ABSTRACT In order to initially colonize a host, bacteria must avoid various components of the innate immune system, one of which is complement. The genus Bordetella includes three closely related species that differ in their ability to resist complement-mediated killing. Bordetella parapertussis and Bordetella bronchiseptica resist killing in naïve serum, a characteristic that may aid in efficient respiratory tract colonization and has been attributed to expression of O antigen. Bordetella pertussis lacks O antigen and is sensitive to naïve serum in vitro, yet it also efficiently colonizes the respiratory tract. Based on these observations, we hypothesized that B. pertussis may have an alternate mechanism to resist complement in vivo. While a number of reports on serum sensitivity of the bordetellae have been published, we show here that serum concentration and growth conditions can greatly alter the observed level of sensitivity to complement and that all but one strain of B. pertussis observed were sensitive to some level of naïve serum in vitro, particularly when there was excess complement. However, B. pertussis rapidly acquires increased resistance in vivo to naïve serum that is specific to the alternative pathway. Resistance is not efficiently acquired by B. parapertussis and B. bronchiseptica mutants lacking O antigen. This B. pertussis-specific mechanism of complement resistance does not appear to be dependent on either brkA or other genes expressed specifically in the Bvg+ phase. This in vivo acquisition of alternative pathway resistance suggests that there is a novel O antigen-independent method by which B. pertussis evades complement-mediated killing.

scholarly journals Effect of d-Lactate on the Physiological Activity of the ArcB Sensor Kinase in Escherichia coli

2004 ◽  
Vol 186 (7) ◽  
pp. 2085-2090 ◽  
Author(s):  
Claudia Rodriguez ◽  
Ohsuk Kwon ◽  
Dimitris Georgellis
Keyword(s):  
Kinase Activity ◽  
Response Regulator ◽  
Physiological Activity ◽  
Growth Conditions ◽  
Sensor Kinase ◽  
Two Component System ◽  
Direct Signal ◽  
Two Component

ABSTRACT The Arc two-component system, comprising the ArcB sensor kinase and the ArcA response regulator, modulates the expression of numerous genes in response to the respiratory growth conditions. Under anoxic growth conditions ArcB autophosphorylates and transphosphorylates ArcA, which in turn represses or activates its target operons. The anaerobic metabolite d-lactate has been shown to stimulate the in vitro autophosphorylating activity of ArcB. In this study, the in vivo effect of d-lactate on the kinase activity of ArcB was assessed. The results demonstrate that d-lactate does not act as a direct signal for activation of ArcB, as previously proposed, but acts as a physiologically significant effector that amplifies ArcB kinase activity.

scholarly journals In VivoGene Essentiality and Metabolism inBordetella pertussis

mSphere ◽  
2019 ◽  
Vol 4 (3) ◽  
Author(s):  
Laura A. Gonyar ◽  
Patrick E. Gelbach ◽  
Dennis G. McDuffie ◽  
Alexander F. Koeppel ◽  
Qing Chen ◽  
...  
Keyword(s):  
Respiratory Tract ◽  
Murine Model ◽  
Whooping Cough ◽  
Critical Role ◽  
Respiratory Illness ◽  
Human Respiratory Tract ◽  
Content Type ◽  
Gene Essentiality

ABSTRACTBordetella pertussisis the causative agent of whooping cough, a serious respiratory illness affecting children and adults, associated with prolonged cough and potential mortality. Whooping cough has reemerged in recent years, emphasizing a need for increased knowledge of basic mechanisms ofB. pertussisgrowth and pathogenicity. While previous studies have provided insight intoin vitrogene essentiality of this organism, very little is known aboutin vivogene essentiality, a critical gap in knowledge, sinceB. pertussishas no previously identified environmental reservoir and is isolated from human respiratory tract samples. We hypothesize that the metabolic capabilities ofB. pertussisare especially tailored to the respiratory tract and that many of the genes involved inB. pertussismetabolism would be required to establish infectionin vivo. In this study, we generated a diverse library of transposon mutants and then used it to probe gene essentialityin vivoin a murine model of infection. Using the CON-ARTIST pipeline, 117 genes were identified as conditionally essential at 1 day postinfection, and 169 genes were identified as conditionally essential at 3 days postinfection. Most of the identified genes were associated with metabolism, and we utilized two existing genome-scale metabolic network reconstructions to probe the effects of individual essential genes on biomass synthesis. This analysis suggested a critical role for glucose metabolism and lipooligosaccharide biosynthesisin vivo. This is the first genome-wide evaluation ofin vivogene essentiality inB. pertussisand provides tools for future exploration.IMPORTANCEOur study describes the firstin vivotransposon sequencing (Tn-seq) analysis ofB. pertussisand identifies genes predicted to be essential forin vivogrowth in a murine model of intranasal infection, generating key resources for future investigations intoB. pertussispathogenesis and vaccine design.

Effect of pyocyanin and 1-hydroxyphenazine on in vivo tracheal mucus velocity

1989 ◽  
Vol 67 (1) ◽  
pp. 316-323 ◽  
Author(s):  
N. C. Munro ◽  
A. Barker ◽  
A. Rutman ◽  
G. Taylor ◽  
D. Watson ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Respiratory Tract ◽  
Guinea Pigs ◽  
Bolus Dose ◽  
Ringer Solution ◽  
Human Respiratory Tract ◽  
Tracheal Mucus

Products of the bacterium Pseudomonas aeruginosa have been shown to slow the beating of human respiratory tract cilia in vitro. We have tested the effects of two of these compounds, pyocyanin and 1-hydroxyphenazine (given as a bolus dose dissolved in 2 microliters Ringer solution), on tracheal mucus velocity of radiolabeled erythrocytes in anesthetized guinea pigs. 1-Hydroxyphenazine (200 ng) caused a rapid slowing of tracheal mucus velocity (maximum fall 47% at 20 min) with recovery by 1 h. The effect of pyocyanin was slower in onset, 600 ng causing 60% reduction in tracheal mucus velocity at 3 h, and no recovery occurred. A combination of pyocyanin and 1-hydroxyphenazine produced an initial rapid slowing equivalent to the same dose of 1-hydroxyphenazine given alone, but the later slowing attributed to pyocyanin was greater than the same dose administered alone. This study demonstrates one mechanism by which products of P. aeruginosa may facilitate its colonization of the respiratory tract.

scholarly journals Analysis of Cigarette Smoke Deposition Within an In Vitro Exposure System for Simulating Exposure in the Human Respiratory Tract

2016 ◽  
Vol 27 (1) ◽  
Author(s):  
Shinkichi Ishikawa ◽  
Yasufumi Nagata ◽  
Takuya Suzuki
Keyword(s):  
Respiratory Tract ◽  
Cigarette Smoke ◽  
Chemical Exposure ◽  
Cigarette Smoke Exposure ◽  
Human Respiratory Tract ◽  
Exposure System ◽  
Direct Exposure ◽  
Air Liquid Interface

SummaryFor the risk assessment of airborne chemicals, a variety of in vitro direct exposure systems have been developed to replicate airborne chemical exposure in vivo. Since cells at the air-liquid interface are exposed to cigarette smoke as an aerosol in direct exposure systems, it is possible to reproduce the situation of cigarette smoke exposure in the human respiratory system using this device. However it is difficult to know whether the exposed cigarette smoke in this system is consistent with the smoke retained in the human respiratory tract. The purpose of this study is to clarify this point using the CULTEX

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