Inductively Coupled Plasma Optical Emission Spectrometry (ICP‐OES) Analysis of Lead Bioaccumulation in Chlamydomonas reinhardtii and the Role of Cia7 Gene

Abstract

The indiscriminate use of heavy metals in human activities has become a threat for the biochemical equilibrium and geochemical cycles of nature. To survive in heavy‐metal polluted environments, some microorganisms have developed a variety of detoxifying mechanisms. An excellent model organism for the study of heavy metal tolerance and homeostasis is Chlamydomonas reinhardtii, a unicellular green haploid microalga. The purpose of this research project was to identify the function of the novel gene Cia7 in C. reinhardtii, and specifically, to determine if it has a role in heavy metal tolerance. It was hypothesized that wild type C. reinhardtii (CC4425) would exhibit less bioaccumulation and higher resistance heavy metal stress; while a mutant strain in which Cia7 has been suppressed (CC5013), would exhibit inhibited growth and higher metal bioaccumulation compared to the wild type. In this study, both strains of C. reinhardtii were treated with either 0 μM or 150 μM of Pb(NO3)2 solution. Lead bioaccumulation after three days of treatment was determined by inductively coupled plasma optical emission spectrometry (ICP‐OES). Chlorophyll concentration and cell growth analysis were also performed. Both strains of C. reinhardtii were treated with increasing concentrations of lead, and absorbance readings at 663, 645, 730 nm were taken on 3‐day intervals over a 15‐day treatment period. Results from ICP‐OES analysis showed no difference in lead bioaccumulation between both strains. The wild type strain (CC4425) demonstrated a relatively higher growth rate than the mutant (CC5013). Chlorophyll concentration and growth in the wild type strain decrease as the concentration of lead in solution increases. On the other hand, chlorophyll concentration and growth in the mutant strain was observed to increase with a higher treatment of lead.Support or Funding InformationACT on Ideas ‐ Texas A&M International University/College of Arts and Sciences ‐ Texas A&M International UniversityThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.