scholarly journals ModifyingSaccharomyces cerevisiaeAdhesion Properties Regulates Yeast Ecosystem Dynamics

mSphere ◽  
2018 ◽  
Vol 3 (5) ◽  
Author(s):  
Debra Rossouw ◽  
Skye P. Meiring ◽  
Florian F. Bauer
Keyword(s):  
Gene Expression ◽  
Gene Family ◽  
Yeast Species ◽  
Genetic System ◽  
Physical Contact ◽  
Relative Fitness ◽  
Independent Evidence ◽  
Content Type ◽  
Metabolic Interactions ◽  
The Impact

ABSTRACTPhysical contact between yeast species, in addition to better-understood and reported metabolic interactions, has recently been proposed to significantly impact the relative fitness of these species in cocultures. Such data have been generated by using membrane bioreactors, which physically separate two yeast species. However, doubts persist about the degree that the various membrane systems allow for continuous and complete metabolic contact, including the exchange of proteins. Here, we provide independent evidence for the importance of physical contact by using a genetic system to modify the degree of physical contact and, therefore, the degree of asexual intraspecies and interspecies adhesion in yeast. Such adhesion is controlled by a family of structurally related cell wall proteins encoded by theFLOgene family. As previously shown, the expression of specific members of theFLOgene family inSaccharomyces cerevisiaedramatically changes the coadhesion patterns between this yeast and other yeast species. Here, we use this differential aggregation mediated byFLOgenes as a model to assess the impact of physical contact between different yeast species on the relative fitness of these species in simplified ecosystems. The identity of theFLOgene has a marked effect on the persistence of specific non-Saccharomycesyeasts over the course of extended growth periods in batch cultures. Remarkably,FLO1andFLO5expression often result in opposite outcomes. The data provide clear evidence for the role of physical contact in multispecies yeast ecosystems and suggest thatFLOgene expression may be a major factor in such interactions.IMPORTANCEThe impact of direct (physical) versus indirect (metabolic) interactions between different yeast species has attracted significant research interest in recent years. This is due to the growing interest in the use of multispecies consortia in bioprocesses of industrial relevance and the relevance of interspecies interactions in establishing stable synthetic ecosystems. Compartment bioreactors have traditionally been used in this regard but suffer from numerous limitations. Here, we provide independent evidence for the importance of physical contact by using a genetic system, based on theFLOgene family, to modify the degree of physical contact and, therefore, the degree of asexual intraspecies and interspecies adhesion in yeast. Our results show that interspecies contact significantly impacts population dynamics and the survival of individual species. Remarkably, different members of theFLOgene family often lead to very different population outcomes, further suggesting thatFLOgene expression may be a major factor in such interactions.

scholarly journals FgHtf1 Regulates Global Gene Expression towards Aerial Mycelium and Conidiophore Formation in the Cereal Fungal Pathogen Fusarium graminearum

2020 ◽  
Vol 86 (9) ◽  
Author(s):  
Gaili Fan ◽  
Huawei Zheng ◽  
Kai Zhang ◽  
Veena Devi Ganeshan ◽  
Stephen Obol Opiyo ◽  
...  
Keyword(s):  
Gene Expression ◽  
Transcription Factors ◽  
Gene Family ◽  
Fusarium Graminearum ◽  
Target Genes ◽  
Homeobox Gene ◽  
Global Gene Expression ◽  
Binding Motifs ◽  
Content Type ◽  
Aerial Growth

ABSTRACT The homeobox gene family of transcription factors (HTF) controls many developmental pathways and physiological processes in eukaryotes. We previously showed that a conserved HTF in the plant-pathogenic fungus Fusarium graminearum, Htf1 (FgHtf1), regulates conidium morphology in that organism. This study investigated the mechanism of FgHtf1-mediated regulation and identified putative FgHtf1 target genes by a chromatin immunoprecipitation assay combined with parallel DNA sequencing (ChIP-seq) and RNA sequencing. A total of 186 potential binding peaks, including 142 genes directly regulated by FgHtf1, were identified. Subsequent motif prediction analysis identified two DNA-binding motifs, TAAT and CTTGT. Among the FgHtf1 target genes were FgHTF1 itself and several important conidiation-related genes (e.g., FgCON7), the chitin synthase pathway genes, and the aurofusarin biosynthetic pathway genes. In addition, FgHtf1 may regulate the cAMP-protein kinase A (PKA)-Msn2/4 and Ca2+-calcineurin-Crz1 pathways. Taken together, these results suggest that, in addition to autoregulation, FgHtf1 also controls global gene expression and promotes a shift to aerial growth and conidiation in F. graminearum by activation of FgCON7 or other conidiation-related genes. IMPORTANCE The homeobox gene family of transcription factors is known to be involved in the development and conidiation of filamentous fungi. However, the regulatory mechanisms and downstream targets of homeobox genes remain unclear. FgHtf1 is a homeobox transcription factor that is required for phialide development and conidiogenesis in the plant pathogen F. graminearum. In this study, we identified FgHtf1-controlled target genes and binding motifs. We found that, besides autoregulation, FgHtf1 also controls global gene expression and promotes conidiation in F. graminearum by activation of genes necessary for aerial growth, FgCON7, and other conidiation-related genes.

scholarly journals Amino Sugars Reshape Interactions between Streptococcus mutans and Streptococcus gordonii

2020 ◽  
Vol 87 (1) ◽  
Author(s):  
Lulu Chen ◽  
Alejandro R. Walker ◽  
Robert A. Burne ◽  
Lin Zeng
Keyword(s):  
Gene Expression ◽  
Streptococcus Mutans ◽  
Single Species ◽  
Oral Bacteria ◽  
Amino Sugars ◽  
Sequencing Analysis ◽  
Streptococcus Gordonii ◽  
Bacterial Gene ◽  
Content Type ◽  
The Impact

ABSTRACT Amino sugars, particularly glucosamine (GlcN) and N-acetylglucosamine (GlcNAc), are abundant carbon and nitrogen sources supplied in host secretions and in the diet to the biofilms colonizing the human oral cavity. Evidence is emerging that these amino sugars provide ecological advantages to beneficial commensals over oral pathogens and pathobionts. Here, we performed transcriptome analysis on Streptococcus mutans and Streptococcus gordonii growing in single-species or dual-species cultures with glucose, GlcN, or GlcNAc as the primary carbohydrate source. Compared to glucose, GlcN caused drastic transcriptomic shifts in each species of bacteria when it was cultured alone. Likewise, cocultivation in the presence of GlcN yielded transcriptomic profiles that were dramatically different from the single-species results from GlcN-grown cells. In contrast, GlcNAc elicited only minor changes in the transcriptome of either organism in single- and dual-species cultures. Interestingly, genes involved in pyruvate metabolism were among the most significantly affected by GlcN in both species, and these changes were consistent with measurements of pyruvate in culture supernatants. Differing from what was found in a previous report, growth of S. mutans alone with GlcN inhibited the expression of multiple operons required for mutacin production. Cocultivation with S. gordonii consistently increased the expression of two manganese transporter operons (slo and mntH) and decreased expression of mutacin genes in S. mutans. Conversely, S. gordonii appeared to be less affected by the presence of S. mutans but did show increases in genes for biosynthetic processes in the cocultures. In conclusion, amino sugars profoundly alter the interactions between pathogenic and commensal streptococci by reprogramming central metabolism. IMPORTANCE Carbohydrate metabolism is central to the development of dental caries. A variety of sugars available to dental microorganisms influence the development of caries by affecting the physiology, ecology, and pathogenic potential of tooth biofilms. Using two well-characterized oral bacteria, one pathogen (Streptococcus mutans) and one commensal (Streptococcus gordonii), in an RNA deep-sequencing analysis, we studied the impact of two abundant amino sugars on bacterial gene expression and interspecies interactions. The results indicated large-scale remodeling of gene expression induced by GlcN in particular, affecting bacterial energy generation, acid production, protein synthesis, and release of antimicrobial molecules. Our study provides novel insights into how amino sugars modify bacterial behavior, information that will be valuable in the design of new technologies to detect and prevent oral infectious diseases.

scholarly journals Use of a Phosphorylation Site Mutant To Identify Distinct Modes of Gene Repression by the Control of Virulence Regulator (CovR) in Streptococcus pyogenes

2017 ◽  
Vol 199 (18) ◽  
Author(s):  
Nicola Horstmann ◽  
Pranoti Sahasrabhojane ◽  
Hui Yao ◽  
Xiaoping Su ◽  
Samuel A. Shelburne
Keyword(s):  
Gene Expression ◽  
Streptococcus Pyogenes ◽  
Response Regulator ◽  
Phosphorylation Site ◽  
Virulence Gene ◽  
Content Type ◽  
Virulence Gene Expression ◽  
Superficial Skin ◽  
Virulence Regulator ◽  
The Impact

ABSTRACT Control of the virulence regulator/sensor kinase (CovRS) two-component system (TCS) serves as a model for investigating the impact of signaling pathways on the pathogenesis of Gram-positive bacteria. However, the molecular mechanisms by which CovR, an OmpR/PhoB family response regulator, controls virulence gene expression are poorly defined, partly due to the labile nature of its aspartate phosphorylation site. To better understand the regulatory effect of phosphorylated CovR, we generated the phosphorylation site mutant strain 10870-CovR-D53E, which we predicted to have a constitutive CovR phosphorylation phenotype. Interestingly, this strain showed CovR activity only for a subset of the CovR regulon, which allowed for classification of CovR-influenced genes into D53E-regulated and D53E-nonregulated groups. Inspection of the promoter sequences of genes belonging to each group revealed distinct promoter architectures with respect to the location and number of putative CovR-binding sites. Electrophoretic mobility shift analysis demonstrated that recombinant CovR-D53E protein retains its ability to bind promoter DNA from both CovR-D53E-regulated and -nonregulated groups, implying that factors other than mere DNA binding are crucial for gene regulation. In fact, we found that CovR-D53E is incapable of dimerization, a process thought to be critical to OmpR/PhoB family regulator function. Thus, our global analysis of CovR-D53E indicates dimerization-dependent and dimerization-independent modes of CovR-mediated repression, thereby establishing distinct mechanisms by which this critical regulator coordinates virulence gene expression. IMPORTANCE Streptococcus pyogenes causes a wide variety of diseases, ranging from superficial skin and throat infections to life-threatening invasive infections. To establish these various disease manifestations, Streptococcus pyogenes requires tightly coordinated production of its virulence factor repertoire. Here, the response regulator CovR plays a crucial role. As an OmpR/PhoB family member, CovR is activated by phosphorylation on a conserved aspartate residue, leading to protein dimerization and subsequent binding to operator sites. Our transcriptome analysis using the monomeric phosphorylation mimic mutant CovR-D53E broadens this general notion by revealing dimerization-independent repression of a subset of CovR-regulated genes. Combined with promoter analyses, these data suggest distinct mechanisms of CovR transcriptional control, which allow for differential expression of virulence genes in response to environmental cues.

scholarly journals The Impact of Leadered and Leaderless Gene Structures on Translation Efficiency, Transcript Stability, and Predicted Transcription Rates in Mycobacterium smegmatis

2020 ◽  
Vol 202 (9) ◽  
Author(s):  
Tien G. Nguyen ◽  
Diego A. Vargas-Blanco ◽  
Louis A. Roberts ◽  
Scarlet S. Shell
Keyword(s):  
Gene Expression ◽  
Mycobacterium Tuberculosis ◽  
Mycobacterium Smegmatis ◽  
Half Life ◽  
Untranslated Regions ◽  
Translation Efficiency ◽  
Production Rates ◽  
Content Type ◽  
The Impact ◽  
Mrna Half Life

ABSTRACT Regulation of gene expression is critical for Mycobacterium tuberculosis to tolerate stressors encountered during infection and for nonpathogenic mycobacteria such as Mycobacterium smegmatis to survive environmental stressors. Unlike better-studied models, mycobacteria express ∼14% of their genes as leaderless transcripts. However, the impacts of leaderless transcript structures on mRNA half-life and translation efficiency in mycobacteria have not been directly tested. For leadered transcripts, the contributions of 5′ untranslated regions (UTRs) to mRNA half-life and translation efficiency are similarly unknown. In M. tuberculosis and M. smegmatis, the essential sigma factor, SigA, is encoded by a transcript with a relatively short half-life. We hypothesized that the long 5′ UTR of sigA causes this instability. To test this, we constructed fluorescence reporters and measured protein abundance, mRNA abundance, and mRNA half-life and calculated relative transcript production rates. The sigA 5′ UTR conferred an increased transcript production rate, shorter mRNA half-life, and decreased apparent translation rate compared to a synthetic 5′ UTR commonly used in mycobacterial expression plasmids. Leaderless transcripts appeared to be translated with similar efficiency as those with the sigA 5′ UTR but had lower predicted transcript production rates. A global comparison of M. tuberculosis mRNA and protein abundances failed to reveal systematic differences in protein/mRNA ratios for leadered and leaderless transcripts, suggesting that variability in translation efficiency is largely driven by factors other than leader status. Our data are also discussed in light of an alternative model that leads to different conclusions and suggests leaderless transcripts may indeed be translated less efficiently. IMPORTANCE Tuberculosis, caused by Mycobacterium tuberculosis, is a major public health problem killing 1.5 million people globally each year. During infection, M. tuberculosis must alter its gene expression patterns to adapt to the stress conditions it encounters. Understanding how M. tuberculosis regulates gene expression may provide clues for ways to interfere with the bacterium’s survival. Gene expression encompasses transcription, mRNA degradation, and translation. Here, we used Mycobacterium smegmatis as a model organism to study how 5′ untranslated regions affect these three facets of gene expression in multiple ways. We furthermore provide insight into the expression of leaderless mRNAs, which lack 5′ untranslated regions and are unusually prevalent in mycobacteria.

scholarly journals Properties of Gene Expression and Chromatin Structure with Mechanically Regulated Transcription

2018 ◽  
Author(s):  
Stuart A. Sevier ◽  
Herbert Levine
Keyword(s):  
Gene Expression ◽  
Mechanical Properties ◽  
Dna Structure ◽  
Genetic System ◽  
Dna Supercoiling ◽  
Simple Description ◽  
Gene Orientation ◽  
Physical Elements ◽  
Transcriptional Bursting ◽  
The Impact

The mechanical properties of transcription have emerged as central elements in our understanding of gene expression. Recent work has been done introducing a simple description of the basic physical elements of transcription where RNA elongation, RNA polymerase (RNAP) rotation and DNA supercoiling are coupled [1]. Here we generalize this framework to accommodate the behavior of many RNAPs operating on multiple genes on a shared piece of DNA. The resulting framework is combined with well-established stochastic processes of transcription resulting in a model which characterizes the impact of the mechanical properties of transcription on gene expression and DNA structure. Transcriptional bursting readily emerges as a common phenomenon with origins in the geometric nature of the genetic system and results in the bounding of gene expression statistics. Properties of a multiple gene system are examined with special attention paid to role that genome composition (gene orientation, size, and intergenic distance) plays in the ability of genes to transcribe. The role of transcription in shaping DNA structure is examined and the possibility of transcription driven domain formation is discussed.PACS numbers:

scholarly journals Transcription Profiles Associated with Inducible Adhesion in Candida parapsilosis

mSphere ◽  
2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Joseph M. Bliss ◽  
George A. Tollefson ◽  
Abigail Cuevas ◽  
Sarah J. Longley ◽  
Matthew N. Neale ◽  
...  
Keyword(s):  
Gene Expression ◽  
Gene Family ◽  
Candida Parapsilosis ◽  
Expression Profiles ◽  
Gene Expression Profiles ◽  
Enrichment Analysis ◽  
Gene Families ◽  
Mammalian Host ◽  
Emerging Infections ◽  
Content Type

ABSTRACT Candida parapsilosis has emerged as a frequent cause of invasive candidiasis with increasing evidence of unique biological features relative to C. albicans. As it adapts to conditions within a mammalian host, rapid changes in gene expression are necessary to facilitate colonization and persistence in this environment. Adhesion of the organism to biological surfaces is a key first step in this process and is the focus of this study. Building on previous observations showing the importance of a member of the ALS gene family in C. parapsilosis adhesion, three clinical isolates were cultured under two conditions that mimic the mammalian host and promote adhesion, incubation at 37°C in tissue culture medium 199 or in human plasma. Transcriptional profiles using RNA-seq were obtained in these adhesion-inducing conditions and compared to profiles following growth in yeast media that suppress adhesion to identify gene expression profiles associated with adhesion. Overall gene expression profiles among the three strains were similar in both adhesion-inducing conditions and distinct from adhesion-suppressing conditions. Pairwise analysis among the three growth conditions identified 133 genes that were differentially expressed at a cutoff of ±4-fold, with the most upregulated genes significantly enriched in iron acquisition and transmembrane transport, while the most downregulated genes were enriched in oxidation-reduction processes. Gene family enrichment analysis identified gene families with diverse functions that may have an important role in this important step for colonization and disease. IMPORTANCE Invasive Candida infections are frequent complications of the immunocompromised and are associated with substantive morbidity and mortality. Although C. albicans is the best-studied species, emerging infections by non-albicans Candida species have led to increased efforts to understand aspects of their pathogenesis that are unique from C. albicans. C. parapsilosis is a frequent cause of invasive infections, particularly among premature infants. Recent efforts have identified important virulence mechanisms that have features distinct from C. albicans. C. parapsilosis can exist outside a host environment and therefore requires rapid modifications when it encounters a mammalian host to prevent its clearance. An important first step in the process is adhesion to host surfaces. This work takes a global, nonbiased approach to investigate broad changes in gene expression that accompany efficient adhesion. As such, biological pathways and individual protein targets are identified that may be amenable to manipulation to reduce colonization and disease from this organism.

scholarly journals Privatization of Biofilm Matrix in Structurally Heterogeneous Biofilms

mSystems ◽  
2020 ◽  
Vol 5 (4) ◽  
Author(s):  
Simon B. Otto ◽  
Marivic Martin ◽  
Daniel Schäfer ◽  
Raimo Hartmann ◽  
Knut Drescher ◽  
...  
Keyword(s):  
Gene Expression ◽  
Shear Stress ◽  
Content Type ◽  
Matrix Gene ◽  
Starting Point ◽  
The Matrix ◽  
Matrix Components ◽  
Biofilm Development ◽  
The Impact

ABSTRACT The self-produced biofilm provides beneficial protection for the enclosed cells, but the costly production of matrix components makes producer cells susceptible to cheating by nonproducing individuals. Despite detrimental effects of nonproducers, biofilms can be heterogeneous, with isogenic nonproducers being a natural consequence of phenotypic differentiation processes. For instance, in Bacillus subtilis biofilm cells differ in production of the two major matrix components, the amyloid fiber protein TasA and exopolysaccharides (EPS), demonstrating different expression levels of corresponding matrix genes. This raises questions regarding matrix gene expression dynamics during biofilm development and the impact of phenotypic nonproducers on biofilm robustness. Here, we show that biofilms are structurally heterogeneous and can be separated into strongly and weakly associated clusters. We reveal that spatiotemporal changes in structural heterogeneity correlate with matrix gene expression, with TasA playing a key role in biofilm integrity and timing of development. We show that the matrix remains partially privatized by the producer subpopulation, where cells tightly stick together even when exposed to shear stress. Our results support previous findings on the existence of “weak points” in seemingly robust biofilms as well as on the key role of linkage proteins in biofilm formation. Furthermore, we provide a starting point for investigating the privatization of common goods within isogenic populations. IMPORTANCE Biofilms are communities of bacteria protected by a self-produced extracellular matrix. The detrimental effects of nonproducing individuals on biofilm development raise questions about the dynamics between community members, especially when isogenic nonproducers exist within wild-type populations. We asked ourselves whether phenotypic nonproducers impact biofilm robustness, and where and when this heterogeneity of matrix gene expression occurs. Based on our results, we propose that the matrix remains partly privatized by the producing subpopulation, since producing cells stick together when exposed to shear stress. The important role of linkage proteins in robustness and development of the structurally heterogeneous biofilm provides an entry into studying the privatization of common goods within isogenic populations.

Consequences of customer engagement and customer self-brand connection

2018 ◽  
Vol 32 (4) ◽  
pp. 387-399 ◽  
Author(s):  
Miguel Ángel Moliner ◽  
Diego Monferrer-Tirado ◽  
Marta Estrada-Guillén
Keyword(s):  
Financial Performance ◽  
Structural Equation ◽  
Banking Sector ◽  
Physical Contact ◽  
Customer Engagement ◽  
Equation Modeling ◽  
Content Type ◽  
New Information ◽  
Empirical Perspective ◽  
The Impact

Purpose The purpose of this paper is to analyze the impact of the customer engagement and customer self-brand connection on customer advocacy and firms’ financial performance. The research focuses on the financial sector and studies a complex organization with a uniform strategy, but which attends the public in different centers (bank branches). Design/methodology/approach A theoretical model of effects is tested using dyadic methodology, with 225 dyads (bank branch manager – average of five customers). The authors use structural equation modeling (EQS6.1) to test the relationships. Findings The results corroborate the hypotheses, with the exception of the influence of customer self-brand connection on financial performance. These analyses show that in the banking sector, where the intensive use of new information and technologies has led to a reduction in direct physical contact with the customer, the off-line experience continues to have a notable economic impact. Furthermore, investment in the brand from an experiential approach determines customer advocacy. Originality/value The contribution of this paper is twofold. This research analyzes from a theoretical and empirical perspective the impact of the customer engagement and customer self-brand connection on customer advocacy and firms’ financial performance.

scholarly journals Staphylococcus aureus Responds to Physiologically Relevant Temperature Changes by Altering Its Global Transcript and Protein Profile

mSphere ◽  
2021 ◽  
Vol 6 (2) ◽  
Author(s):  
Raeven A. Bastock ◽  
Emily C. Marino ◽  
Richard E. Wiemels ◽  
Donald L. Holzschu ◽  
Rebecca A. Keogh ◽  
...  
Keyword(s):  
Gene Expression ◽  
Staphylococcus Aureus ◽  
Environmental Conditions ◽  
Large Temperature ◽  
Small Scale ◽  
Content Type ◽  
Temperature Changes ◽  
Invasive Infections ◽  
The Impact ◽  
Definite Temperature

ABSTRACT Staphylococcus aureus is an opportunistic pathogen that colonizes the anterior nares of 30 to 50% of the population. Colonization is most often asymptomatic; however, self-inoculation can give rise to potentially fatal infections of the deeper tissues and blood. Like all bacteria, S. aureus can sense and respond to environmental cues and modify gene expression to adapt to specific environmental conditions. The transition of S. aureus from the nares to the deeper tissues and blood is accompanied by changes in environmental conditions, such as nutrient availability, pH, and temperature. In this study, we perform transcriptomics and proteomics on S. aureus cultures growing at three physiologically relevant temperatures, 34°C (nares), 37°C (body), and 40°C (pyrexia), to determine if small scale, biologically meaningful alterations in temperature impact S. aureus gene expression. Results show that small but definite temperature changes elicit a large-scale restructuring of the S. aureus transcriptome and proteome in a manner that, most often, inversely correlates with increasing temperature. We also provide evidence that a large majority of these changes are modulated at the posttranscriptional level, possibly by sRNA regulatory elements. Phenotypic analyses were also performed to demonstrate that these changes have physiological relevance. Finally, we investigate the impact of temperature-dependent alterations in gene expression on S. aureus pathogenesis and demonstrate decreased intracellular invasion of S. aureus grown at 34°C. Collectively, our results demonstrate that small but biologically meaningful alterations in temperature influence S. aureus gene expression, a process that is likely a major contributor to the transition from a commensal to pathogen. IMPORTANCE Enteric bacterial pathogens, like Escherichia coli, are known to experience large temperature differences as they are transmitted through the fecal oral route. This change in temperature has been demonstrated to influence bacterial gene expression and facilitate infection. Staphylococcus aureus is a human-associated pathogen that can live as a commensal on the skin and nares or cause invasive infections of the deeper tissues and blood. Factors influencing S. aureus nasal colonization are not fully understood; however, individuals colonized with S. aureus are at increased risk of invasive infections through self-inoculation. The transition of S. aureus from the nose (colonization) to the body (infection) is accompanied by a modest but definite temperature increase, from 34°C to 37°C. In this study, we investigate whether these host-associated small temperature changes can influence S. aureus gene expression. Results show widespread changes in the bacterial transcriptome and proteome at three physiologically relevant temperatures (34°C, 37°C, and 40°C).

scholarly journals Pathogenicity of Dodecyltrimethylammonium Chloride-Resistant Salmonella enterica

2013 ◽  
Vol 79 (7) ◽  
pp. 2371-2376 ◽  
Author(s):  
Megan J. M. Kautz ◽  
Aleksey Dvorzhinskiy ◽  
Jonathan G. Frye ◽  
Natalie Stevenson ◽  
Diane S. Herson
Keyword(s):  
Gene Expression ◽  
Real Time ◽  
Parental Strain ◽  
Salmonella Enterica ◽  
Invasive Disease ◽  
Multidrug Resistant ◽  
Content Type ◽  
Culture Cells ◽  
Dodecyltrimethylammonium Chloride ◽  
The Impact

ABSTRACTSalmonellainfection causes a self-limiting gastroenteritis in humans but can also result in a life-threatening invasive disease, especially in old, young, and/or immunocompromised patients. The prevalence of antimicrobial and multidrug-resistantSalmonellahas increased worldwide since the 1980s. However, the impact of antimicrobial resistance on the pathogenicity ofSalmonellastrains is not well described. In our study, a microarray was used to screen for differences in gene expression between a parental strain and a strain ofSalmonella entericaserovar Enteritidis with reduced susceptibility (SRS) to the widely used antimicrobial sanitizer dodecyltrimethylammonium chloride (DTAC). Three of the genes, associated with adhesion, invasion, and intracellular growth (fimA,csgG, andspvR), that showed differences in gene expression of 2-fold or greater were chosen for further study. Real-time reverse transcriptase PCR (real-time RT-PCR) was used to confirm the microarray data and to compare the expression levels of these genes in the parental strain and four independently derived SRS strains. All SRS strains showed lower levels of gene expression offimAandcsgGthan those of the parental strain. Three of the four SRS strains showed lower levels ofspvRgene expression while one SRS strain showed higher levels ofspvRgene expression than those of the parental strain. Transmission electron microscopy determined that fimbriae were absent in the four SRS strains but copiously present in the parental strain. All four SRS strains demonstrated a significantly reduced ability to invade tissue culture cells compared to the parental strains, suggesting reduced pathogenicity of the SRS strains.

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