ABSTRACT: We report the use of Next Generation RNA Sequencing for confirming or improving initial identification of small regulatory RNA in Staphylococcus aureus to prodive a list of the most probable RNA molecules transcribed as independent units. Extraction of RNAs in exponential phase of growth in Newman and N315 strains
Project description:GAPDHs from human pathogens S. aureus and P. aeruginosa can be readily inhibited by ROS-mediated direct oxidation of their catalytic active cysteines. Because of the rapid degradation of H2O2 by bacterial catalase, only steady-state but not one-dose treatment of H2O2 induces rapid metabolic reroute from glycolysis to pentose phosphate pathway (PPP). We conducted RNA-seq analyses to globally profile the bacterial transcriptomes in response to a steady level of H2O2, which reveals profound transcriptional changes including the induced expression of glycolytic genes in both bacteria. Our results revealed that the inactivation of GAPDH by H2O2 induces a metabolic reroute from glycolysis to PPP; the elevated levels of fructose 1,6-biphosphate (FBP) and 2-keto-3-deoxy-6-phosphogluconate (KDPG) lead to dissociation of their corresponding glycolytic repressors (GapR and HexR, respectively) from their cognate promoters, thus resulting in derepression of the glycolytic genes to overcome H2O2-stalled glycolysis in S. aureus and P. aeruginosa, respectively. Given that H2O2 can be produced constitutively by the host immune response, exposure to the steady-state stress of H2O2 recapitulates more accurately bacterial responses to host immune system in vivo. RNA-seq in Pseudomonas aeruginosa and Staphylococus aureus under steady state of H2O2
Project description:S. aureus is one of the major human pathogens that greatly impacts individuals and causes a variety of illnesses ranging from minor skin infections to life-threatening diseases, such as endocarditis, pneumonia, septicemia and toxic shock syndrome. Stk1/Stp1 are particular important for S. aureus pathogenesis and survival as they are thought to participate in regulating virulence, cell wall structure and antibiotic resistance. Understanding how Ser/Thr phosphorylation regulates virulence and antibiotic resistance will provide foundation for the development of novel therapeutic strategies against S. aureus infection. The phosphoproteomic analysis of Staphylococcus aureus Newman strain led to the identification of 76 peptides with mapped phosphorylation sites belonging to 29 distinct proteins. In the case of Stk1, only one peptide (residues 157-182), with the sequence ALSETSLTQTNHVLGTVQYFSPEQAK, was predicted to have a cluster of six phosphorylation sites (Ser159, Thr161, Ser162, Thr164, Thr166 and Thr172). This segment overlaps with the sequence of kinase activation loop (residues 154-176) in Stk1. Further biochemical studies revealed cis autophosphorylation of Thr172 in the GT/S motif is necessary for self-activation and kinase activity of Stk1, whereas the trans autophosphorylation of other activation loop serines/threonins are essential for the optimal kinase activity of Stk1.
Project description:Small non-coding RNAs that associate with Piwi proteins, called piRNAs, serve as guides for repression of diverse transposable elements in germ cells of Metazoa. In Drosophila, the genomic regions that give rise to piRNAs, the so-called piRNA clusters, are transcribed to generate long precursor molecules that are processed into mature piRNAs. How genomic regions that give rise to piRNA precursor transcripts are differentiated from the rest of the genome and how these transcripts are specifically channeled into the piRNA biogenesis pathway are not known. We found that trans-generationally inherited piRNAs provide the critical trigger for piRNA production from homologous genomic regions in the next generation by two different mechanisms. First, inherited piRNAs enhance processing of homologous transcripts into mature piRNAs by initiating the ping-pong cycle in the cytoplasm. Second, inherited piRNAs induce installment of the H3K9me3 mark on genomic piRNA cluster sequences. The HP1 homolog Rhino binds to the H3K9me3 mark through its chromodomain and is enriched over piRNA clusters. Rhino recruits the piRNA biogenesis factor Cutoff to piRNA clusters and is required for efficient transcription of piRNA precursors. We propose that trans-generationally inherited piRNAs act as an epigenetic memory for identification of substrates for piRNA biogenesis on two levels, by inducing a permissive chromatin environment for piRNA precursor synthesis and by enhancing processing of these precursors. total RNA sequencing of RNA from ovaries of cuff+/- or cuff-/- flies
Project description:Staphylococcus aureus can infect a wide range of animals and pose as a serious threat to public health by transferring via animals or animal-derived food stuff. Even more importantly, multiple drug resistance development in the bacteria has resulted in therapeutic failure of a number of antibiotics. Therefore by realizing the need of time, this study was designed to investigate the underlying mechanisms of virulence and resistance in S. aureus. After screening through in vivo and in vitro virulence assays and susceptibility test, a highly virulent and multidrug resistant MRSA strain was selected for differential analysis by RNA-seq technology and gene expression results were verified by RT-qPCR. Up-regulation of crucial regulators like sarA and KdpDE seemed to play role in decreased expression of many exotoxin genes while enhanced the adhesion and cell wall protein expression, leading to strong biofilm production in the presence of inactivated agr system. In addition to resistance genes like blaZ, ermC and femA, up-regulation of vraS and multidrug ABC transporter genes contributed to the multidrug resistance in MRSA. Fluoroquinolone resistance was attributed to mutational changes in gyrA and parC genes. Our findings suggested that many virulence and resistance determinants in S. aureus are controlled by complex network of various regulators, and sarA is the most important of those as it adds to pathogenicity of the bacteria and ensures its survival in diverse environment. Further investigations are required to unveil these mechanisms in S. aureus. Four samples were analysed including 2 MRSA1679a test strain and 2 reference strain ATCC1 samples with two replicates of each.
Project description:The S. aureus transcriptome was assessed for strains Newman (wild type) and Newman (sarZ) during both exponential (2hr) and early stationary (5hr) cell growth. The S. aureus transcriptome was assessed for strains Newman (wild type) and Newman (sarZ) during both exponential (2hr) and early stationary (5hr) cell growth. The experiment was performed in duplicate or triplicate, and RNA samples labeled/hybridized to independent commercially available Affymetrix GeneChips
Project description:miRNA expression profiling in tumor-associated BMDCs induced by tumor cells 1D8 or CT-26 in comparison with those cultured in medium. To prepare tumor-associated BMDCs(Bone Marrow-derived Dendritic Cells), murine BMDCs were co-cultured with 1D8 or CT-26 cells in a transwell plate in 1640 medium supplemented with 3% FCS and 1% penicillin and streptomycin for 24 hrs. Total RNAs were isolated using the TRIZOL® Reagent(Invitrogen) according to manufacturer’s instructions.The samples were labeled using the miRCURY™ Array Power labeling kit (Exiqon). miRNA array hybridization was performed, and unbound miRNA Labels were washed away. Microarrays were analyzed using GenePix 4000B scanner and GenePix Pro 6 software (Molecular Devices).
Project description:Investigation of baseline transcription activity of two different clinical isolates of Staphylococcus aureus with two different susceptibility levels to the antibiotics Vancomycin and Daptomycin. Two different strains of Staphylococcus aureus, one that is fully Vancomycin and Daptomycin Sensitive and one with decreased Vancomycin and Daptomycin Sensitivity - grown to mid-log phase in rich broth.
Project description:The S. aureus transcriptome was assessed for strains Newman (wild type) and Newman (sarZ) during both exponential (2hr) and early stationary (5hr) cell growth. Overall design: The S. aureus transcriptome was assessed for strains Newman (wild type) and Newman (sarZ) during both exponential (2hr) and early stationary (5hr) cell growth. The experiment was performed in duplicate or triplicate, and RNA samples labeled/hybridized to independent commercially available Affymetrix GeneChips