Mitochondrial-encoded genes expression profiling of low pH in a single Euplotes crassus

Abstract

Ciliates are known to be extremely sensitive to various environmental factors as single-celled organisms. Euplotes crassus is one of the most dominant species in common inhabitants of sand interstices of the intertidal zone in the world. Also E. crassus are easily cultured in the laboratory condition and have been established the minimum foundation for the molecular study based on RNA. In this study, we firstly devised the method of real time reverse transcription-PCR (RT-PCR) from a single ciliate cell. Secondly, we investigated gene expression profiles related to the stability of ATP synthesis, and verified up-regulated expression of NADH and cytochrome P450 reductase genes with low pH. Since high mRNA expression lead to the reduction of energy supplies for ATP synthesis, potentially the low pH environment needs to increased energy consumption for survival. According to the future climate change scenario (A1B scenario), in 2100, the pH of seawater is expected to decrease from 8.1 to 7.8 due to increasing atmospheric carbon dioxide. We tried to predict the adaptation and the biomass change of ciliates from ocean acidification.