Adaptive responses of outer membrane porin balance of Yersinia ruckeri under different incubation temperature, osmolarity, and oxygen availability

Abstract

The capability of Yersinia ruckeri to survive in the aquatic systems reflects its adaptation (most importantly through the alteration of membrane permeability) to the unfavorable environments. The nonspecific porins are a key factor contributing to the permeability. Here we studied the influence of the stimuli, such as temperature, osmolarity, and oxygen availability on regulation of Y. ruckeri porins. Using qRT-PCR and SDS-PAGE methods we found that major porins are tightly controlled by temperature. Hyperosmosis did not repress OmpF production. The limitation of oxygen availability led to decreased expression of both major porins and increased transcription of the minor porin OmpY. Regulation of the porin balance in Y. ruckeri, in spite of some similarities, diverges from that system in Escherichia coli. The changes in porin regulation can be adapted in Y. ruckeri in a species-specific manner determined by its aquatic habitats.

Keywords: Bacteria; environmental signal/stress responses; gene expression/regulation; outer membrane proteins; porins..