Project description:In order to ensure the reproducibility of the transcriptional response of Halobacterium NRC-1 to oxic/anoxic transitions, we repeated global mRNA measurements for the oxygen time series data in GSE5924, except that cultures were equilibrated to low oxygen for 24 hours prior to the start of the experiment rather than 12 hours, and time course sampling continued to 12 hours post-shift to high oxygen rather than stopping at 6 hours. The results of these data suggest that there is good reproducibility between datasets, and that Halobacterium responds robustly to oxic/anoxic transitions. Keywords: time course
Project description:This project was conducted by Nitin S. Baliga of the Halobacterium group at the Institute for Systems Biology in collaboration with Jocelyne Diruggiero of University of Maryland. Halobacterium NRC-1 cell pellets were resuspended in an isotonic buffer at a low density, placed on ice and exposed to 200J/m2 of UV-C irradiation, returned to the growth medium and allowed to recover at 42oC in dark (D) or light (L). Total RNA was collected from each sample at 30 minutes (D30 and L30) and 60 minutes (L60 and D60). The control (C) was processed in a manner to identical to L60 except that it did not suffer any UV-C insult. The reference RNA was prepared from an aliquot of the same culture just prior to UV-C irradiation. Therefore the reference was also exposed to initial perturbations prior to UV-C irradiation such as change of growth medium to buffer and change of temperature from 42oC to ice. Keywords = ISB Keywords = Halobacterium NRC-1 Keywords = UV repair Keywords = ultraviolet radiation Keywords = stress response Keywords: other
Project description:We report detailed characterization of physiological changes encoded by 63% of all genes within the archaeon Halobacterium salinarum subsp. NRC-1 during routine laboratory growth. While the majority of these changes occur during the transition from rapid exponential growth to the stationary phase, we were also able to detect transient changes in gene expression. This demonstrated the presence of several additional albeit subtle physiological states that exist beyond what might be anticipated from a direct interpretation of the growth profile. Changes in the abundance of several key intracellular metabolites over the growth curve corroborated observations of changes in gene expression of enzymes that catalyze their synthesis. Next, we investigated the roles of general transcription factors (GTFs) in mediating these global growth-associated gene expression changes. This revealed numerous phenotypic perturbations including slowed growth, gas vesicle biogenesis deficiency and morphologic abnormalities upon the overexpression of a single GTF - TBPd. These phenotypes were quantified and were attributed to a perturbation in the regulation of aconitase. Importantly, our results demonstrate why an experiment design as simple as a simple batch culture can be enormously informative of activities and interrelationships of a large fraction of all genes in a microbe. This SuperSeries is composed of the following subset Series: GSE14832: Halobacterium growth in standard growth media: time course GSE14835: Halobacterium growth with added uracil: time course GSE14836: Halobacterium delta-ura3 growth with added uracil: time course Refer to individual Series