UC Merced

Chlamydia species are obligated intracellular pathogens that proliferate only within infected cells. Currently, there are no known techniques or systems used to investigate host metabolites directed by Chlamydia infected epithelial cells. To fill this gap, we observed relative ATP concentration at different compartments (nucleus, Inclusion, and cytoplasm) of C. trachomatis infected cells utilizing non-invasive Raman microscopy methods. Our objective was to develop Raman spectroscopy for characterizing the chemical composition of fixed infected cells. We found the intensity of Raman spectra for the inclusion is much greater than the nucleus which has a greater intensity than the cytosol. Comparing the upward-going and the negative-going peaks of nucleus spectrum minus intensified cytoplasm spectrum, there are more amino acids (specifically adenine) and ATP present in the nucleus and there is more RNA in the cytosol. In addition, inclusion minus intensified cytoplasm shows more fatty acids and adenine in the inclusion, whereas the cytosol contains more RNA. By gathering Raman spectra of inclusion, nucleus, and cytoplasm, we measured and analyzed the concentration of manipulated metabolites, such as ATP, pre and post Chlamydia infected cells. Thus Raman microscopy is one of the few non-invasive methods to investigate chlamydia infected cells.