{'fraction_non_alphanumeric': 0.03098220171390903, 'fraction_numerical': 0.005273566249176005, 'mean_word_length': 5.432203389830509, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Tracing the uptake of gold in Toxoplasma gondii using STEM-EDS

Approximately 30-50% of global population is infected with Toxoplasma gondii [1] and current treatments are more than 50 years old. New more efficacious and less toxic treatments are needed. We have previously demonstrated that auranofin, a gold containing drug, has anti-T. gondii activity [2]. While auranofin anti-T.gondii mechanism of action is still unknown, there is enough evidence suggesting that auranofin’s gold molecule is responsible for its anti-parasitic effects. Specific drug delivery is fundamental to ensure treatment efficacy and reduce considerable toxicity in host cells, therefore, elucidating whether gold enters the target parasite is paramount. Transmission electron microscopy, because of its powerful nanometer lateral resolution, is an advantageous tool in analyzing the distribution of drugs inside a cell or an infectious pathogen. Herein, we used scanning transmission electron microscopy-energy dispersive Xray spectroscopy (STEM-EDS) to study the uptake of gold(I) by T. gondii extracellular tachyzoites treated with auranofin. Different to TEM, scanning transmission electron microscopy (STEM) uses convergent beam scanning over the specimen and an X-ray spectrometer detects the characteristic X-rays emitted by atoms in a sample. Energy-dispersive X-ray spectroscopy (EDS) is therefore a suitable technique to chemically characterize the uptake of gold inside T.gondii and to demonstrate gold entry into the parasite.