Complete Genome Sequence and Transcriptomic Analysis of the Novel Pathogen Elizabethkingia anophelis in Response to Oxidative Stress.
Bottom Line: Chrome azurol sulfonate assay verified that siderophore production of E. anophelis is increased in the presence of oxidative stress.We further showed that hemoglobin facilitates the growth, hydrogen peroxide tolerance, cell attachment, and biofilm formation of E. anophelis NUHP1.Our study suggests that siderophore production and heme uptake pathways might play essential roles in stress response and virulence of the emerging pathogen E. anophelis.
Affiliation: School of Biological Sciences, Nanyang Technological University, Singapore.Show MeSH
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Mentions: We used the chrome azurol sulfonate (CAS) liquid assay, a universal siderophore detection method (Schwyn and Neilands 1987), to measure the siderophore produced by E. anophelis. The color of CAS assay solution changes from blue to yellow when siderophores in sample solutions chelate iron from CAS, which also leads to decrease in absorbance at 630 nm. The freshly prepared CAS solution was first mixed with a commercially available iron siderophore, deferoxamine, which gave a dose-dependent decrease of the absorbance at 630 nm (fig. 4A). Supernatants of the E. anophelis cultivated in LB contained siderophore activity, which is able to decrease the absorbance at 630 nm to a level close to 20 μM of deferoxamine (fig. 4B). In accordance with the transcriptomic analysis, E. anophelis cultivated in the presence of sublethal H2O2 concentration (20 mM) produced a significantly larger quantity of siderophore compared with E. anophelis cultivated in medium alone (fig. 4B). We noted that the presence of H2O2 will lead to certain interference of the CAS assay of the LB medium control (fig. 4B). However, the concentration of H2O2 in the E. anophelis overnight cultures should be rather low due to the neutralization of secreted catalase.Fig. 4.—
Affiliation: School of Biological Sciences, Nanyang Technological University, Singapore.