Project description:After performing multiplex PCR, we analysed extracted DNA (500 ng ssDNA) from 9 Mycobacterium tuberculosis clinical isolates to detect multidrug resistance. In addition, a mixed strain situation was simulated by mixing wild type Mtb CDC1551 (20 ng) with 4 concentrations of Mtb mutant DNA (1 ng, 250 pg, 62.5 pg, and 15.6 pg), which is equivalent to relative concentrations of 5%, 1.25%, 0.31% and 0.08% Mtb mutant DNA.
Project description:This project describes the isoniazid (INH) resistance acquisition event in Mycobacterium tuberculosis (Mtb) from the proteomics perspective. In this way, an exploration of the protein differences, comparing clonal INH susceptible (INHs) and INHr pairs of Mtb were evaluated. One clonal clinical and one clonal laboratory-derived Mtb pair with different susceptibility profiles to INH were studied. The laboratory INHr strain had one katG mutation (V1A), while the clinical INHr strain had two (V1A and E3V). Large-scale bacterial cultures were grown in triplicate to obtain secreted proteins as well as proteins from cell fractions. The resulting peptide solutions from all fractions were analyzed using liquid-chromatography coupled with tandem mass spectrometry (LC-MS/MS). LC-MS/MS spectra were compared against an Mtb database to determine the protein abundance. Protein abundance differences were tested by Student’s t test. Looking at the same cellular fractions, there were 25 commonly altered Mtb proteins after acquiring INH resistance. These proteins were involved in ATP synthase machinery, lipid metabolism, regulatory events, virulence, detoxification and adaptation processes.
Project description:Goal: Assess transcriptional changes in Mtb associated with activation of adenylyl cyclase activity in the bacterium, by treatment with the Rv1625c agonist V-59 or activation of the TetOn-cAMP construct. Specifically, address changes in transcription of cholestrrol utilization genes, during growth of Mtb in cholesterol media. Method: WT, Rv1625c knockout, and Rv1625c Complement strains of Mtb were grown in cholesterol-based media and treated with V-59 or vehicle control (DMSO). V-59 is known to increase cAMP synthesis in WT, but not in Rv1625c knockout Mtb. V-59 increases cAMP synthesis above that observed in WT in the Complement strain, due to Rv1625c overexpression in this strain. Also, utilized TetOn-cAMP Mtb strain, to induce cAMP synthesis independent of V-59 and Rv1625c. Treatment with Atc induces expression of catalytic domain of Rv1264 in this strain. We grew the TetOn-cAMP strain in cholesterol-based media, treated with Atc or EtOH (vehicle control). Conclusions: Transcriptional changes to cholesterol utilization genes associated with V-59 treatment in WT Mtb were similar to those associated with TetOn-cAMP induction. The transcriptional changes associated with blockade of cholesterol degradation following V-59 treatment in WT Mtb were not observed in the Rv1625c knockout strain. The Rv1625c knockout strain had intrinsic defects in induction of cholesterol utilization genes. The Complement strain showed enhanced transcriptional changes in response to V-59 treatment.