Functional Genomics Investigation of Microbial Physiology in the Hyperthermophilic Microorganisms Pyrococcus furiosus and Thermotoga maritima

Abstract

DNA microarray chips were used to examine steady and transient growth in the hyperthermophilic microorganisms Thermotoga maritima and Pyrococcus furiosus. Continuous culture growth experiments were used to investigate the utility of ANOVA-based mixed model analyses and the reproducibility of cDNA microarray data in T. maritima. Gene expression was assessed in three different mechanical steady states corresponding to two separate dilution rates (D=0.25 hr⁻¹ and D=0.17 hr⁻¹) at two distinct temperatures (80°C and 85°C). Of the 422 genes that were differentially regulated between mechanical steady states, a total of 93 genes also showed significant variability in gene expression within a steady state. Besides considering the reproducibility of gene expression data, it was found that T. maritima and P. furiosus responded to physiological stimuli at the transcriptional level. Like T. maritima, P. furiosus had discriminating mechanisms to acquire, process and regulate the utilization of simple and complex sources of carbon. In addition, the presence of yeast extract and S0 in the medium induced numerous transcriptional changes in P. furiosus. Also, thermal stress induced expression of genes encoding important molecular chaperones and genes encoding proteins important to the stabilization and repair of DNA and down-regulated the transcription of genes involved in energy metabolism in both organisms. Consequently, the heat shock response was similar between these two model hyperthermophiles, even though they originate from separate domains of life.

Description

Keywords

heat shock, hyperthermophiles, DNA microarray, Thermotoga maritima, Pyrococcus furiosus

Citation

Degree

PhD

Discipline

Chemical Engineering

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