Project description:To understand transcriptional regulation of probiotic bacteria under acidic condition, RNAseq analysis was carried out over different growth conditions
Project description:We have performred RNA-seq analysis of WT and ∆phoR Mtb H37Rv under normal and acidic stress, to investigate the role of PhoR in maintaning the pH homoeostasis of bacterium. RNA was extracted from exponentially growing mycobacterial cells in Middlebrook 7H9 media. For acid stress, cells at OD600 of 0.6 were pelleted, washed twice with 7H9 medium buffered with 100 mM MOPS or 2N HCl for pH 7.0 or pH 4.5, respectively, re-suspended in media of indicated pH, and finally the cells were grown further for 2 hours at 37°C. After incubation cells were combined with 40 ml of 5 M guanidinium thiocyanate solution containing 1% β-mercaptoethanol and 0.5% Tween 80. Cells were pelleted by centrifugation, and lysed by re-suspending in 1 ml Trizol (Ambion) in the presence of Lysing Matrix B (100 µm silica beads; MP Bio) using a FastPrep-24 bead beater (MP Bio) at a speed setting of 6.0 for 30 seconds. The procedure was repeated for 2-3 cycles with incubation on ice in between pulses. Next, cell lysates were centrifuged at 13000 rpm for 10 minutes; supernatant was collected and processed for RNA isolation using Direct-ZolTM RNA isolation kit (ZYMO) as per manufacturer’s recommendation. Following extraction, RNA was treated with DNAse I (Promega) to degrade contaminating DNA, and integrity was assessed using a Nanodrop (ND-1000, Spectrophotometer). RNA samples were further checked for intactness of 23S and 16S rRNA using formaldehyde-agarose gel electrophoresis, and Qubit fluoremeter (Invitrogen). RNA integrity was checked using Agilent 2200 Tape Station system (Agilent Technologies). Library construction, RNA-sequencing and data analysis have been carried out by Agrigenome Labs Private Limited (Cochin), India. The main purpose of this study is to understand how mycobacteria can sense acidic stress conditions and mount an appropriate stress response.
Project description:Mycobacterium avium complex (MAC), including Mycobacterium avium and Mycobacterium intracellulare (MI), accounts for a significant portion of nontuberculous mycobacterial lung disease affecting immunocompromised and lung structural disease patients. Adapting pathogens to a host-induced hostile environment is critical to establishing infection and persistence within the host. However, the cellular and molecular mechanisms of stress response for MAC still need to be elucidated. In this study, we analyzed the transcriptional profile of MI under acidic and oxidative stress conditions using RNA-seq. At the transcriptome level, 80 genes were shown [FC] ≥2.0 and p <0.05 under oxidative stress with 10 mM hydrogen peroxide. In detail, 77 genes were upregulated, while 3 genes were downregulated. Also, 878 genes were shown [FC] ≥2.0 and p <0.05 under acidic stress with pH 4.5. Among these genes, 339 were upregulated, while 539 were downregulated. Functional analysis revealed the activation of several pathways, including nitrogen and sulfur metabolism, under acidic stress conditions. On the contrary, oxidative stress conditions activated DNA replication and repair pathways. Our data demonstrate the activation of nitrogen and sulfur metabolism in MAC infection, which could be crucial for persistence and survival under stress conditions encountered within the host during infection. In conclusion, this study suggests the importance of stress responses in MAC pathogenesis and identifies potential therapeutic target pathways.
Project description:Bacteria cope with and adapt to stress by modulating gene expression in response to specific environmental cues. In this study the transcriptional response of lactobacillus plantarum CAUH2 to oxidative stress conditions was investigated via RNA-seq. The work provides detailed insights into the mechanisms through which L. plantarum responds to oxidative stress conditions and increases understanding of bacterial adaptation in natural and industrial settings.
Project description:Transcriptional profiling of probiotic Lactobacillus rhamnosus strain GG mid-exponential pH-controlled bioreactor cultures before and after exposure to bovine bile (0.2% ox gall). Keywords: bile, stress response
Project description:We used a whole genome array containing 97.4 % of the annotated genes of Lactobacillus acidophilus NCFM, a probiotic culture that belongs to the lactic acid bacteria group, to identify genes that are differentially expressed under several stress conditions. Keywords: Stress response
Project description:Transcriptional profiling of probiotic Lactobacillus rhamnosus strain GG mid-exponential pH-controlled bioreactor cultures before and after exposure to bovine bile (0.2% ox gall). Keywords: bile, stress response Cell samples from four biological replicates were harvested right before (time point 0 min) and 10, 30 and 120 min after bile treatment. Each sample was compared to a common reference sample (time point 0 min, mid-exponential growth phase Lactobacillus rhamnosus GG cultures). A total of 12 hybridizations were performed using balanced dye-swap design. Dyes were balanced between compared sample pairs and between biological replicates.