Project description:Arthrobacter sp. CGMCC 3584 are able to produce high yields of extracellular cyclic adenosine monophosphate (cAMP), which plays a vital role in the field of treatment of disease and animal food, during aerobic fermentation. DNA array-based transcriptional analysis of Arthrobacter cells was conducted to elucidate the higher productivity of cAMP under high oxygen supply. Results showed that 14.1% and 19.3% of the whole genome genes were up-regulated and down-regulated notably, respectively. The largest group with altered transcriptional levels belonged to the group involved in carbohydrate transport and metabolism. Other large functional groups of differentially expressed genes changed significantly included amino acid transport and metabolism, inorganic ion transport and metabolism and transcription. Overall design: The agitations were set as 150 r/min and 350 r/min to construct low oxygen supply and high oxygen supply conditions, respectively, a 5-L fermenter. Samples (three biological replicates) were respectively collected at 12h, 24h, 36h and 48h under two different oxygen supply conditions for transcriptional analysis. Equal samples of each of the independent biological replicates were mixed together for DNA microarray analysis. Genes expression level ratios (high oxygen supply/low oxygen supply) ≥ 2 or ≤ 0.5 were considered to be significantly regulated.
Project description:In previous work in our group, shotgun genome sequencing of Arthrobacter sp. revealed potential new P450 monooxygenases and many other oxidoreductases with putative hydroxylation activity. A targeted approach to identify enzymes involved in the degradation of certain molecules is proteomic analysis. In the case of growth on certain substances, enzymes like P450s, which are responsible for the observed organism’s capabilities, might be overexpressed or initially induced.
Project description:Arthrobacter chlorophenolicus A6 is a 4-chlorophenol degrading soil bacterium with high phyllosphere colonization capacity. Till now the genetic basis for the phyllosphere competency of Arthrobacter or other pollutant-degrading bacteria is uncertain. We investigated global gene expression profile of A. chlorophenolicus grown in the phyllosphere of common bean (Phaseolus vulgaris) compared to growth on agar surfaces. We designed transcriptome arrays and investigated which genes had different transcript levels in the phyllosphere of common bean (Phaseolus vulgaris) as compared to agar surfaces. Since water availability is considered an important factor in phyllosphere survival and activity, we included both high and low relative humidity treatments for the phyllosphere-grown cells. In addition, we determined the expression profile under pollutant exposure by the inclusion of two agar surface treatments, i.e. with and without 4-chlorophenol.