scholarly journals A Novel LysR-Type Global Regulator RpvA Controls Persister Formation and Virulence in Staphylococcus aureus

2019 ◽  
Author(s):  
Jian Han ◽  
Zhe Liu ◽  
Tao Xu ◽  
Wanliang Shi ◽  
Xiaogang Xu ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Target Genes ◽  
Transcriptional Profiling ◽  
Lethal Dose ◽  
Carotenoid Biosynthesis ◽  
New Drugs ◽  
Dihydroxyacetone Phosphate ◽  
Intermediate Metabolites ◽  
Candidate Target ◽  
Gel Shift Assay

AbstractStaphylococcus aureus is the leading cause of wound and nosocomial infections. Persister formation and virulence factors play crucial roles during S. aureus infection. However, the mechanisms of persister formation and its relationship to virulence in S. aureus are poorly understood. In this study, we screened a transposon mutant library and identified a LysR-type global transcriptional regulator NWMN_0037, which we called RpvA, for regulator of persistence and virulence, whose mutation leads to higher susceptibility to antibiotics ampicillin and norfloxacin and various stresses including oxidative stress, heat, and starvation in late exponential and early stationary phase. Interestingly, the rpvA mutant was highly attenuated for virulence compared with the parent S. aureus Newman strain as shown by a much higher lethal dose, reduced ability to survive in macrophages and to form abscess in the mouse model. Transcriptional profiling and metabolomic analysis revealed that RpvA could repress multiple genes including gapR, gapA, tpi, pgm, eno, glpD, and acs expression and enhance production of numerous intermediate metabolites including dihydroxyacetone phosphate, 2-phosphoglycerate, acetyl-CoA, glycerol 3-phosphate, L-glutamate in the cells. The differentially expressed genes and altered production of metabolites are distributed in global metabolism including carbohydrate metabolism, amino acid metabolism, energy metabolism and metabolism of cofactors and vitamins. These metabolic adjustments could cause the cell to go into dormancy, thus promoting S. aureus to convert to persisters. In addition, RpvA could upregulate the expression of virulence genes including hla, hlgA, hlgB, hlgC, lukF, lukS, lukD, sea and coa, and carotenoid biosynthesis genes (crtI, crtM, crtN). Gel shift assay confirmed that RpvA could bind to the promoters of candidate target genes hla, hlgB and crtM, thus promoting S. aureus virulence. Because of the important functions of the RpvA, it may serve as an attractive target for developing new drugs and vaccines to more effectively control S. aureus infections.

scholarly journals Transcriptional Profiling Analysis of the Global Regulator NorG, a GntR-Like Protein of Staphylococcus aureus

2011 ◽  
Vol 193 (22) ◽  
pp. 6207-6214 ◽  
Author(s):  
Q. C. Truong-Bolduc ◽  
P. M. Dunman ◽  
T. Eidem ◽  
D. C. Hooper
Keyword(s):  
Staphylococcus Aureus ◽  
Target Genes ◽  
Efflux Pump ◽  
Transcriptional Profiling ◽  
Fold Increase ◽  
Regulatory Function ◽  
Drug Transporter ◽  
Content Type ◽  
Global Regulators ◽  
Inorganic Ion

The GntR-like protein NorG has been shown to affectStaphylococcus aureusgenes involved in resistance to quinolones and β-lactams, such as those encoding the NorB and AbcA transporters. To identify the target genes regulated by NorG, we carried out transcriptional-profiling assays usingS. aureusRN6390 and its isogenicnorG::catmutant. Our data showed that NorG positively affected the transcription of global regulatorsmgrA,arlS, andsarZ. The three putative drug efflux pump genes most positively affected by NorG were the NorB efflux pump (5.1-fold), the MmpL-like protein SACOL2566 (5.2-fold), and the BcrA-like drug transporter SACOL2525 (5.7-fold) genes. TheS. aureuspredicted MmpL protein showed 53% homology with the MmpL lipid transporter ofMycobacterium tuberculosis, and the putative SACOL2525 protein showed 87% homology with the bacitracin drug transporter BcrA ofStaphylococcus hominis. Two pump genes most negatively affected by NorG were the NorC (4-fold) and AbcA (6-fold) genes. Other categories of genes, such as those participating in amino acid, inorganic ion, or nucleotide transporters and metabolism, were also affected by NorG. Real-time reverse transcription (RT)-PCR assays formgrA,arlS,sarZ,norB,norC,abcA,mmpL, andbcrA-like were carried out to verify microarray data and showed the same level of up- or downregulation by NorG. ThenorGmutant showed a 2-fold increase in resistance to norfloxacin and rhodamine, both substrates of the NorC transporter, which is consistent with the resistance phenotype conferred by overexpression ofnorCon a plasmid. These data indicate that NorG has broad regulatory function inS. aureus.

scholarly journals Expression of SarX, a Negative Regulator of agr and Exoprotein Synthesis, Is Activated by MgrA in Staphylococcus aureus

2006 ◽  
Vol 188 (12) ◽  
pp. 4288-4299 ◽  
Author(s):  
Adhar C. Manna ◽  
Ambrose L. Cheung
Keyword(s):  
Staphylococcus Aureus ◽  
Target Genes ◽  
Protein Family ◽  
Negative Regulator ◽  
Upstream Region ◽  
Family Control ◽  
Expression Of Genes ◽  
Important Regulator ◽  
Gel Shift Assay

ABSTRACT The expression of genes involved in the pathogenesis of Staphylococcus aureus is known to be controlled by global regulatory loci, including agr, sarA, saeRS, arlRS, and sarA-like genes. As part of our continuing efforts to understand the regulatory mechanisms that involve sarA-like genes, we describe here the characterization of a novel transcriptional regulator called SarX, a member of the SarA protein family. The transcription of sarX was growth phase dependent and was expressed maximally during the stationary phase of growth, which was significantly decreased in the mgrA mutant. MgrA acted as an activator of sarX expression as confirmed by transcriptional fusion and Northern blot analyses. Purified MgrA protein bound to the upstream region of the sarX promoter as demonstrated by gel shift assay. The expression levels of various potential target genes involved in virulence and regulation, specifically those affected by sarA and mgrA, were analyzed with isogenic sarX mutant strains. Our data indicated that SarX acted as a repressor of the agr locus and consequently target genes regulated by the agr system. We propose that SarX is an important regulator in the SarA protein family and may be part of the common pathway by which agr and members of the sarA gene family control virulence in S. aureus.

Antimicrobial and cytotoxic activity of Macrophomina phaseolina isolated from gummosis infected citrus reticulata

2013 ◽  
pp. 125-133
Author(s):  
Rubal C Das ◽  
Rajib Banik ◽  
Robiul Hasan Bhuiyan ◽  
Md Golam Kabir
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Brine Shrimp ◽  
Inhibitory Concentration ◽  
Lethal Dose ◽  
Macrophomina Phaseolina ◽  
Chloroform Extract ◽  
Citrus Reticulata ◽  
Gram Negative Bacteria ◽  
Gram Negative

Macrophomina phaseolina is one of the pathogenic organisms of gummosis disease of orange tree (Citrus reticulata). The pathogen was identified from the observation of their colony size, shape, colour, mycelium, conidiophore, conidia, hyaline, spore, and appressoria in the PDA culture. The crude chloroform extracts from the organism showed antibacterial activity against a number of Gram positive and Gram-negative bacteria. The crude chloroform extract also showed promising antifungal activity against three species of the genus Aspergillus. The minimum inhibitory concentration (MIC) of the crude chloroform extract from M. phaseolina against Bacillus subtilis, Staphylococcus aureus, Escherichia coli, and Shigella sonnie were 128 ?gm, 256 ?gm, 128 ?gm and 64 ?gm/ml respectively. The LD50 (lethal dose) values of the cytotoxicity assay over brine shrimp of the crude chloroform extract from M. phaseolina was found to be 51.79 ?gm/ml. DOI: http://dx.doi.org/10.3329/cujbs.v5i1.13378 The Chittagong Univ. J. B. Sci.,Vol. 5(1 &2):125-133, 2010

scholarly journals Sulforaphane Inhibits the Expression of Long Noncoding RNA H19 and Its Target APOBEC3G and Thereby Pancreatic Cancer Progression

Cancers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 827
Author(s):  
Yiqiao Luo ◽  
Bin Yan ◽  
Li Liu ◽  
Libo Yin ◽  
Huihui Ji ◽  
...  
Keyword(s):  
Cancer Progression ◽  
Colony Formation ◽  
Noncoding Rna ◽  
Target Genes ◽  
Gene Array ◽  
New Drugs ◽  
Tumor Promoter ◽  
Ductal Adenocarcinoma ◽  
Pilot Studies

Pancreatic ductal adenocarcinoma (PDAC) is extremely malignant and the therapeutic options available usually have little impact on survival. Great hope is placed on new therapeutic targets, including long noncoding RNAs (lncRNAs), and on the development of new drugs, based on e.g., broccoli-derived sulforaphane, which meanwhile has shown promise in pilot studies in patients. We examined whether sulforaphane interferes with lncRNA signaling and analyzed five PDAC and two nonmalignant cell lines, patient tissues (n = 30), and online patient data (n = 350). RT-qPCR, Western blotting, MTT, colony formation, transwell and wound healing assays; gene array analysis; bioinformatics; in situ hybridization; immunohistochemistry and xenotransplantation were used. Sulforaphane regulated the expression of all of five examined lncRNAs, but basal expression, biological function and inhibition of H19 were of highest significance. H19 siRNA prevented colony formation, migration, invasion and Smad2 phosphorylation. We identified 103 common sulforaphane- and H19-related target genes and focused to the virus-induced tumor promoter APOBEC3G. APOBEC3G siRNA mimicked the previously observed H19 and sulforaphane effects. In vivo, sulforaphane- or H19 or APOBEC3G siRNAs led to significantly smaller tumor xenografts with reduced expression of Ki67, APOBEC3G and phospho-Smad2. Together, we identified APOBEC3G as H19 target, and both are inhibited by sulforaphane in prevention of PDAC progression.

Screening candidate microR-15a- IRAK2 regulatory pairs for predicting the response to Staphylococcus aureus-induced mastitis in dairy cows

2019 ◽  
Vol 86 (4) ◽  
pp. 425-431 ◽  
Author(s):  
Zhi Chen ◽  
Jingpeng Zhou ◽  
Xiaolong Wang ◽  
Yang Zhang ◽  
Xubin Lu ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Differential Expression ◽  
High Throughput Sequencing ◽  
Target Genes ◽  
Interleukin 1 ◽  
Differentially Expressed ◽  
Luciferase Reporter ◽  
Expression Of Genes ◽  
Chinese Holstein Cows ◽  
Reporter Assays

AbstractWe established a mastitis model using exogenous infection of the mammary gland of Chinese Holstein cows with Staphylococcus aureus and extracted total RNA from S. aureus-infected and healthy mammary quarters. Differential expression of genes due to mastitis was evaluated using Affymetrix technology and results revealed a total of 1230 differentially expressed mRNAs. A subset of affected genes was verified via Q-PCR and pathway analysis. In addition, Solexa high-throughput sequencing technology was used to analyze profiles of miRNA in infected and healthy quarters. These analyses revealed a total of 52 differentially expressed miRNAs. A subset of those results was verified via Q-PCR. Bioinformatics techniques were used to predict and analyze the correlations among differentially expressed miRNA and mRNA. Results revealed a total of 329 pairs of negatively associated miRNA/mRNA, with 31 upregulated pairs of mRNA and 298 downregulated pairs of mRNA. Differential expression of miR-15a and interleukin-1 receptor-associated kinase-like 2 (IRAK2), were evaluated by western blot and luciferase reporter assays. We conclude that miR-15a and miR-15a target genes (IRAK2) constitute potential miRNA–mRNA regulatory pairs for use as biomarkers to predict a mastitis response.

scholarly journals Investigating the Transcriptome of Candida albicans in a Dual-Species Staphylococcus aureus Biofilm Model

2021 ◽  
Vol 11 ◽  
Author(s):  
Bryn Short ◽  
Christopher Delaney ◽  
Emily McKloud ◽  
Jason L. Brown ◽  
Ryan Kean ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Candida Albicans ◽  
Biofilm Formation ◽  
Driving Forces ◽  
Transcriptional Profiling ◽  
Specific Interaction ◽  
Opportunistic Pathogen ◽  
Virulence Proteins ◽  
Biofilm Model ◽  
Upregulated Genes

Candida albicans is an opportunistic pathogen found throughout multiple body sites and is frequently co-isolated from infections of the respiratory tract and oral cavity with Staphylococcus aureus. Herein we present the first report of the effects that S. aureus elicits on the C. albicans transcriptome. Dual-species biofilms containing S. aureus and C. albicans mutants defective in ALS3 or ECE1 were optimised and characterised, followed by transcriptional profiling of C. albicans by RNA-sequencing (RNA-seq). Altered phenotypes in C. albicans mutants revealed specific interaction profiles between fungus and bacteria. The major adhesion and virulence proteins Als3 and Ece1, respectively, were found to have substantial effects on the Candida transcriptome in early and mature biofilms. Despite this, deletion of ECE1 did not adversely affect biofilm formation or the ability of S. aureus to interact with C. albicans hyphae. Upregulated genes in dual-species biofilms corresponded to multiple gene ontology terms, including those attributed to virulence, biofilm formation and protein binding such as ACE2 and multiple heat-shock protein genes. This shows that S. aureus pushes C. albicans towards a more virulent genotype, helping us to understand the driving forces behind the increased severity of C. albicans-S. aureus infections.

scholarly journals Uji Bioaktivitas Antibakteri Senyawa murni dari Jamur Endofit Sporothrix sp Terhadap Bakteri Escherichia coli dan Staphylococcus aureus

2019 ◽  
Vol 6 (1) ◽  
pp. 37
Author(s):  
Dewi Yudiana Shinta ◽  
Yusmarini Yusmarini ◽  
Herix Sonata MS ◽  
Hilwan Yuda Teruna ◽  
Saryono Saryono
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Endophytic Fungi ◽  
Positive Control ◽  
Significant Inhibition ◽  
New Drugs ◽  
Diffusion Method ◽  
Significant Difference ◽  
Pure Compounds ◽  
Escherichia Coli Bacteria

Modern medicines that are developing now come from active ingredients isolated from plants that require large amounts of plants. The development of new drugs from endophytic fungi found obstacles in the amount of pure compounds produced. Therefore further research is needed by using endophytic fungi as a new antimicrobial producer. This study aims to see the ability or activity of pure compounds produced by Sporothrix sp endophytic fungi from Dahlia tuber (Dahlia variabilis). Test the activity of pure compounds produced by Sporothrix sp. Endophytic fungi on E. coli and Staphylococcus aureus determined by disc diffusion method. With doses of 10, 30 and 50μg/disk. In Escherichia coli bacteria doses 10 and 50μg/disk gave significant inhibition of pure compounds from isolation compared to the positive control of ciprofloxacin, which was marked by a statistically significant test result (p <0.05). In contrast to Staphylococcus aureus there was no significant difference in doses of both doses of 10.30 and 50μg/disk. Determination of pure compounds was carried out by HPLC and Infra Red Spectrophotometry.

scholarly journals Application of Median Lethal Concentration (LC50) of Pathogenic Microorganisms and Their Antigens in Vaccine Development

2020 ◽  
Author(s):  
Saganuwan Alhaji Saganuwan
Keyword(s):  
Staphylococcus Aureus ◽  
Disease Virus ◽  
Vaccine Development ◽  
Hepatitis A Virus ◽  
Lethal Dose ◽  
Vaccine Dose ◽  
Foot And Mouth Disease ◽  
Bacterial Colony ◽  
Mouth Disease Virus

Abstract Objective: Lack of ideal mathematical models to qualify and quantify both pathogenicity, and virulence is a dreadful setback in development of new antimicrobials and vaccines against resistance pathogenic microorganisms.Hence, the modified arithmetical formula of Reed and Muenchhas been integrated with other formulas and used to determine bacterial colony forming unit/ viral concentration, virulence and immunogenicity from LC50s established in the laboratories. Results: Microorganisms’antigens tested are Staphylococcus aureus, Streptococcuspneumonia, Pseudomonas aeruginosa in mice and rat, Edwardsiellaictaluri, Aeromonashydrophila, Aeromonasveronii in fish, New Castle Disease virus in chicken, Sheep Pox Virus, Foot-and-Mouth Disease Virus and Hepatitis A virus in vitro, respectively. The LC50s for the pathogens using different routes of administrations are 1.93 x 103(sheep poxvirus) and 1.75 x 1010 for Staphylococcus aureus (ATCC29213) in rat respectively. Titre index (TI) equals N log10 LC50 and provides protection against lethal dose in graded fashion which translates to protection index. N is the number of vaccine dose that could neutralize the LC50. Hence, parasite inoculum of 103 to 1011could be used as basis for determination of median lethal dose(LD50), LC50 and median bacterial concentrations (BC50)determination, pathogenic dose for immune stimulation should be sought at concentrations less than LC10.

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