The effects of putative lipase and wax ester synthase/acyl-CoA:diacylglycerol acyltransferase gene knockouts on triacylglycerol accumulation and transcriptome expression in Gordonia sp. KTR9.
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ABSTRACT: Gene disruption of KTR9_0186 resulted in a 2-fold increase in TAG content in nitrogen starved cells. Lipase mutants subjected to carbon starvation, following nitrogen starvation, retained 75% more TAGs and retained pigmentation. Transcriptome expression data confirmed the deletion of KTR9_0186 and identified the up-regulation of key genes involved in fatty acid degradation, a likely compensatory mechanism for reduced TAG mobilization. The Gordonia sp. KTR9 strain used in this study has been previously described (PMID 16332812) A 12 x 135K array study using total RNA recovered from triplicate cultures of KTR9 under carbon starvation and triplicate cultures of KTR9 0186 Mutant under carbon starvation.
Project description:Investigation of gene expression level changes in Gordonia sp. KTR9 and Gordonia sp. KTR9 mutant GlnR upon exposure to high and low nitrogen conditions The Gordonia sp. KTR9 strain used in this study has been previously described by Thompson KT, Crocker FH, Fredrickson HL.2005. Mineralization of the cyclic nitramine explosive hexahydro-1,3,5-trinitro-1,3,5-triazine by Gordonia and Williamsia spp. Appl Environ Microbiol. 2005 Dec;71(12):8265-72. A 12 x 135K array study using total RNA recovered from triplicate cultures of KTR9 exposed to high nitrogen conditions, triplicate cultures of KTR9 exposed to low nitrogen conditions, triplicate cultures of KTR9 mutant GlnR exposed to high nitrogen conditions, triplicate cultures of KTR9 mutant GlnR exposed to low nitrogen conditions.
Project description:Investigation of gene expression level changes in Gordonia sp. KTR9 upon exposure to RDX and Nitrogen Limitation, compared to controls with no RDX. The Gordonia sp. KTR9 strain used in this study has been previously described by Thompson KT, Crocker FH, Fredrickson HL.2005. Mineralization of the cyclic nitramine explosive hexahydro-1,3,5-trinitro-1,3,5-triazine by Gordonia and Williamsia spp. Appl Environ Microbiol. 2005 Dec;71(12):8265-72. A 12 x 135K array study using total RNA recovered from triplicate cultures of KTR9 exposed to RDX, triplicate cultures of KTR9 exposed to RDX and high nitrogen conditions, triplicate cultures of KTR9 exposed to low nitrogen, and triplicate cultures of controls exposed to high nitrogen.
Project description:Zinc is a central player in the metalloproteomes of prokaryotes and eukaryotes. We used a top-down quantitative proteomic approach to reveal the repository of the zinc pools in the proteobacterium Cupriavidus metallidurans. About 60% of the theoretical proteome of C. metallidurans were identified, quantified, and compared between a ΔzupT mutant defect in zinc allocation and its parent strain. In both strains, the number of zinc-binding proteins and their binding sites exceeded that of the zinc ions per cell, indicating that the totality of the zinc proteome provides empty binding sites for incoming zinc ions. This zinc repository plays a central role in zinc homeostasis in C. metallidurans and probably also in other organisms.
Project description:Investigation of the whole genome gene expression level changes relative to exponential phase growth in Nitrosomonas europaea ATCC19718 after 12 hours ammonia starvation, 144 hours ammonia starvation, and 20 minutes following ammonia addition to starved cells. The ammonia monooxygenase of chemolithotrophic ammonia oxidizing bacteria (AOB) catalyzes the first step in ammonia oxidation by converting ammonia to hydroxylamine. The monooxygenase of Nitrosomonas europaea is encoded by two nearly identical operon copies (amoCAB1,2). Several AOB, including N. europaea, also posess a divergent monocistronic copy of amoC (amoC3) of unknown function. Previous work suggested a possible functional role for amoC3 in N. europaea during recovery from extended ammonia starvation as part of the σE- stress response regulon during the recovery of N. europaea from extended ammonia starvation, thus indicating its importance during the exit of cells from starvation. We here used global transcription analysis to show that expression of amoC3 is part of a general post-starvation cellular response system in N. europaea. We also found that amoC3 is required for efficient exit from prolonged ammonia starvation, as deleting this gene impaired growth at elevated temperatures and recovery following starvation under high oxygen tensions. Deletion of the σ32 global stress response regulator demonstrated that the heat shock regulon also plays a significant role in mediating the recovery of N. europaea from starvation. These findings provide the first described phenotype associated with the divergent AmoC3 subunit which appears to function as a stress responsive subunit capable of maintaining ammonia oxidation activity under stress conditions. A twelve chip study using total RNA recovered from four timepoints for each of three biological replicates of wild-type cultures of Nitrosomonas europaea ATCC 19718. Total RNA was obtained from each biological culture replicate during exponential growth, following 12 hours ammonia starvation, 144 hours ammonia starvations, and 20 minutes following ammonia addition to starved cells.
Project description:Transcriptional profiling of Haloferax mediterranei in three culture media with different nitrogen sources: a) cells were grown stationary and exponentially on ammonium, b) cells were grown exponentially on nitrate, and c) cells were shifted to nitrogen starvation conditions. The main differences in the transcriptional profiles have been identified between the cultures with ammonium as nitrogen source and the cultures with nitrate or nitrogen starvation, supporting previous results which indicate the absence of ammonium as the factor causing the expression of genes involved in nitrate assimilation pathway. Four-conditions experiment with four biological replicates, combined in a loop design.
Project description:As multicellular organisms, plants must integrate responses to environmental cues across different cell types and also over time. Nitrate is the major source of available Nitrogen for plants, and a limiting factor for plant growth and productivity. Plant root s are highly impacted by nitrate availability, modifying their architecture to optimize nitrate uptake from soils. In order to understand how this functional response is dynamically orchestrated across different cell types of the root, space and time must be addressed within the same experimental setup. We performed a transcriptomic analysis in five major root cell types of Arabidopsis plants in response to nitrate treatments considering short and long time exposure to this macronutrient. We found nitrate treatment triggers a dynamic reprogramming of root cell gene expression that follows a spatial pattern over time consistent with an early regulation of nitrate transport and assimilation in external layers of the root and a later regulation of hormonal and developmental processes in more internal layers of the root.
Project description:Whole genome gene expression analysis was examined with Ralstonia eutropha strain H16 cultures grown in PHB production medium (recipe per Peoples and Sinskey, 1989) containing fructose or trioleate as the main carbon source. The goal of this analysis was to determine the identity of the triacylglycerol and fatty acid breakdown genes in R. eutropha strain H16. In the study presented here, triplicates of R. eutropha strain H16 were examined for changes in expression of 6702 genes during growth and PHB production on each carbon source.
Project description:In order to provide global information on gene expression during growth on C2 compounds, microarray analysis of M. extorquens AM1 cells was carried out, comparing ethylamine-grown cells to succinate-grown cells. This comparison has confirmed previous observations on the inducible nature of some of the enzymes involved in C2 metabolism, such as methylamine (and ethylamine) utilization system (mau), putative enzymes for converting acetaldehyde into acetate and acetyl-CoA, and enzymes of the ethylmalonyl-CoA pathway that has been proposed to operate for assimilation of acetyl-CoA into cell biomass. RNA from ethylamine-grown cells was compared to RNA from succinate-grown cells. Four biological replicates were carried out.