Project description:Cyanobacteria are oxygenic photoautotrophs notable for their ability to utilize atmospheric CO2 as the major source of carbon. The prospect of using cyanobacteria in converting solar energy and high concentrations of CO2 (e.g. flue gas from coal power plants) efficiently into biomass and renewable energy sources is of interest to many research fields. In order to guide further advances in this area, a better understanding about the metabolic changes that occur under conditions of high CO2 is important. The objective of this study is to utilize genome-wide microarray expression profiling in the unicellular diazotrophic cyanobacterium Cyanothece 51142 grown in 8% CO2-enriched air and to determined the impact of high CO2 on cyanobacterial cell physiology and growth.
Project description:We sought understand the molecular mehcanism of gene regulation by Mga and its contribution to GAS pathogenesis in serotype M59 GAS through whole transcriptome analysis of strains with phosphorylation mimicking substitutions in key histidine residues of Mga.
Project description:GAS strains were grown in THY broth to early exponential phase and RNA extracted. cDNA was generated and the expression profiles were determined using the RMLgenechip. Comparisons between the sample groups allow the identification of genes differentially expressed between strains. This experiment compared pre- and post- mouse passaged GAS strains. Keywords: GAS comparison
Project description:Clonal emergence is a major driver for changes in bacterial disease epidemiology. Recently, it has been proposed that episodic emergence of novel, hypervirulent clones of group A Streptococcus (GAS) results from horizontal gene transfer (HGT) and recombination events leading to increased expression of the cytotoxins Nga (NADase) and SLO (streptolysin O). We previously described a gene fusion event involving the gene encoding the GAS M protein (emm) and an adjacent M-like protein (enn) in the emm4 GAS population, a GAS emm type that lacks the hyaluronic acid capsule. Using whole genome sequencing of a temporally and geographically diverse set of 1,127 isolates, we discovered that the North American emm4 GAS population has undergone clonal replacement with emergent GAS strains completely replacing historical isolates by 2017. Emergent emm4 GAS strains were defined by a handful of small genetic variations, including the emm-enn gene fusion, and showed a marked in vitro growth defect compared to historical strains. In contrast to other previously described GAS clonal emergence events, emergent emm4 GAS lacked significant HGT events and showed no significant increase in transcript levels of nga/slo toxin gene via RNA sequencing and quantitative real-time PCR analysis relative to historic strains. Despite the in vitro growth differences, emergent emm4 GAS strains demonstrated hypervirulence in mouse and ex vivo growth in human blood compared to historical strains. Thus, these data detail the emergence and dissemination of a hypervirulent acapsular GAS clone defined by small genetic variation thereby defining a novel model for GAS strain replacement.
Project description:We sought understand the molecular mehcanism of gene regulation by Mga and its contribution to GAS pathogenesis in serotype M59 GAS through whole transcriptome analysis of strains with phosphorylation mimicking substitutions in key histidine residues of Mga. There were 6 strains analyzed, each in triplicate replicates: 1)wild-type GAS, 2)mga deletion strain 3)mga with alanine at H207 4)mga with aspartate at H207, 5) mga with alanine at H273 6)mga with aspartate at H273
