Project description:The host protein calprotectin inhibits the growth of a variety of bacterial pathogens through metal sequestration in a process known as 'nutritional immunity'. Staphylococcus aureus growth is inhibited by calprotectin in vitro and calprotectin is localized in vivo to staphylococcal abscesses during infection. However, the staphylococcal adaptations that provide defense against nutritional immunity and the role of metal-responsive regulators are not fully characterized. In this work, we define the transcriptional response of S. aureus and the role of the metal-responsive regulators, Zur, Fur, and MntR, in response to metal limitation by calprotectin exposure. Additionally, we identified genes affecting the fitness of S. aureus during metal limitation through a Transposon sequencing (Tn-seq) approach. Loss of function mutations in clpP, which encodes a proteolytic subunit of the ATP-dependent Clp protease, demonstrate reduced fitness of S. aureus to the presence of calprotectin. ClpP contributes to pathogenesis in vivo in a calprotectin-dependent manner. These studies establish a critical role for ClpP to combat metal limitation by calprotectin and reveal the genes required for S. aureus to outcompete the host for metals.
Project description:The host protein calprotectin inhibits the growth of a variety of bacterial pathogens through metal sequestration in a process known as 'nutritional immunity'. Staphylococcus aureus growth is inhibited by calprotectin in vitro and calprotectin is localized in vivo to staphylococcal abscesses during infection. However, the staphylococcal adaptations that provide defense against nutritional immunity and the role of metal-responsive regulators are not fully characterized. In this work, we define the transcriptional response of S. aureus and the role of the metal-responsive regulators, Zur, Fur, and MntR, in response to metal limitation by calprotectin exposure. Additionally, we identified genes affecting the fitness of S. aureus during metal limitation through a Transposon sequencing (Tn-seq) approach. Loss of function mutations in clpP, which encodes a proteolytic subunit of the ATP-dependent Clp protease, demonstrate reduced fitness of S. aureus to the presence of calprotectin. ClpP contributes to pathogenesis in vivo in a calprotectin-dependent manner. These studies establish a critical role for ClpP to combat metal limitation by calprotectin and reveal the genes required for S. aureus to outcompete the host for metals.
Project description:Microorganisms form biofilms containing differentiated cell populations. To determine factors driving differentiation, we study protein distributions in bacterial biofilms using shotgun proteomics. Notably, zinc- and manganese-depleted portions of the biofilm repress the production of anti-staphylococcal molecules. Exposure to calprotectin (a host protein known to sequester metal ions at infectious foci) recapitulates responses occurring within metal-deplete portions of the biofilm and promotes interaction between P. aeruginosa and Staphylococcus aureus. Consistent with these results, the presence of calprotectin promotes co-colonization of the murine lung, and polymicrobial communities are found to co-exist in calprotectin-enriched airspaces of a cystic fibrosis lung explant. These findings, which demonstrate that metal fluctuations are a driving force of microbial community structure, have clinical implications because of the frequent occurrence of P. aeruginosa and S. aureus co-infections.
Project description:Transcriptional profiling of C. elegans young adult worms exposed to pathogen Staphylococcus aureus for 4 hours versus age-matched worms exposed to onctrol lab food E. coli OP50. The goal was to identify genes regulated in response to pathogen. The broader goal of study was to study evolution of pathogen response by comparing this expression profile to that obtained by exposing the nematode Pristionchus pacificus to the same pathogen. Other experiments which are a part of this study include expression profiling of C. elegans and P. pacificus on other pathogens including Staphylococcus aureus, Serratia marcescens, Xenorhabdus nematophila. Keywords: Expression profiling by array One-condition experiments. C. elegans young adults: Exposed to Staphylococcus aureus versus exposed to E. coli OP50 : 4 hours. 4 biological replicates for each condition, including 2 dye-swaps.
Project description:Young adult fer-15;fem-1 Caenorhabditis elegans were infected with Staphylococcus aureus for 8 h to determine the transcriptional host response to Staphylococcus aureus. Analysis of differential gene expression in C. elegans young adults exposed to two different bacteria: E. coli strain OP50 (control), wild-type Staphylococcus aureus RN6390. Samples were analyzed at 8 hours after exposure to the different bacteria. These studies identified C. elegans genes induced by pathogen infection. Keywords: response to pathogen infection, innate immunity, host-pathogen interactions
Project description:Staphylococcus aureus is one of the most important pathogens in humans and animals, multiply resistant strains are increasingly widespread, new agents are needed for the treatment of S. aureus. Rhein, a natural plant product, has potential antimicrobial activity against Staphylococcus aureus. We employed Affymetrix Staphylococcus aureus GeneChipsTM arrays to investigate the global transcriptional profiling of Staphylococcus aureus ATCC25923 treated with rhein. Results provided insight into mechanisms involved in rhein - Staphylococcus aureus interactions. Keywords: rhein response Staphylococcus aureus cells were exposed for 45 minutes to rhein at concentration of 8 µg/ml (1/2à MIC), 6 samples including 3 control samples are analyzed.
Project description:Staphylococcus aureus (S. aureus) is an important human and animal pathogen, multiply resistant strains are increasingly widespread, new agents are needed for the treatment of S. aureus. magnolol has potent antimicrobial activity against S. aureus. We employed Affymetrix Staphylococcus aureus GeneChipsTM arrays to investigate the global transcriptional profiling of Staphylococcus aureus ATCC25923 treated with magnolol. Keywords: gene expression array-based, count Staphylococcus aureus cells were exposed for a certain time to magnolol at a certain concentration, 6 samples including 3 control samples are analyzed.
Project description:Staphylococcus aureus (S. aureus) is an important human and animal pathogen, multiply resistant strains are increasingly widespread, new agents are needed for the treatment of S. aureus. Cryptotanshinone, a natural plant product, has potent antimicrobial activity against S. aureus. We employed Affymetrix Staphylococcus aureus GeneChipsTM arrays to investigate the global transcriptional profiling of Staphylococcus aureus ATCC25923 treated with cryptotanshinone. Keywords: gene expression array-based, count Staphylococcus aureus cells were exposed for 45 minutes to cryptotanshinone at concentration of 2 µg/ml (1/2� MIC), 6 samples including 3 control samples are analyzed.
Project description:Staphylococcus aureus (S. aureus) is an important human and animal pathogen, multiply resistant strains are increasingly widespread, new agents are needed for the treatment of S. aureus. eugenol, a natural plant product, has potent antimicrobial activity against S. aureus. We employed Affymetrix Staphylococcus aureus GeneChipsTM arrays to investigate the global transcriptional profiling of Staphylococcus aureus ATCC25923 treated with eugenol. Keywords: gene expression array-based, count Staphylococcus aureus cells were exposed for 45 minutes to eugenol at concentration of 250µg/ml (1/2× MIC), 2 samples including 1 control samples are analyzed.
Project description:Staphylococcus aureus (S. aureus) is an important human and animal pathogen, multiply resistant strains are increasingly widespread, new agents are needed for the treatment of S. aureus. sodium houttuyfonate has potent antimicrobial activity against S. aureus. We employed Affymetrix Staphylococcus aureus GeneChipsTM arrays to investigate the global transcriptional profiling of Staphylococcus aureus ATCC25923 treated with sodium houttuyfonate. Keywords: gene expression array-based, count Staphylococcus aureus cells were exposed for a certain to sodium houttuyfonate at certain concentration, 6 samples including 3 control samples are analyzed.