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Chem 263 Seminars in Chemical Biology: Prof. Mireille Kamariza

Chem 263 Seminars in Chemical Biology

April 25, 2023 4:00 pm - 5:30 pm
Mani L. Bhaumik Centennial Collaboratory
607 Charles E. Young Dr., East
Los Angeles, CA 90095 United States


Towards Tuberculosis control: A Trehalose-based Detection System for live Mycobacterium tuberculosis

Tuberculosis (TB) is second only to COVID-19 as the most lethal cause of death from a single infectious agent. Current primary methods for diagnosing TB infection present significant limitations such as lengthy time-to-result for phenotypic tests, the need for a priori knowledge of Mycobacterium tuberculosis (Mtb) resistance mutations, and prohibitive cost for molecular tests. Here, we present fluorogenic solvatochomic trehalose probes that enables rapid detection of live Mtb. In particular, we designed a 4-N,N-dimethylamino-1,8-naphthalimide–conjugated trehalose (DMN-Tre) probe that undergoes >700-fold increase in fluorescence intensity when transitioned from aqueous to hydrophobic environments. This enhancement occurs upon metabolic conversion of DMN-Tre to trehalose monomycolate and incorporation into the mycomembrane of Actinobacteria. DMN-Tre labeling enabled the rapid, no-wash visualization of mycobacterial and corynebacterial species without nonspecific labeling of Gram-positive or Gram-negative bacteria. DMN-Tre labeling was detected within minutes and was inhibited by heat killing of mycobacteria. Furthermore, DMN-Tre labeling was reduced by treatment with TB drugs, unlike the clinically used auramine stain. Lastly, DMN-Tre labeled Mtb in TB-positive human sputum samples comparably to auramine staining, suggesting that this operationally simple method may be deployable for TB diagnosis.
Tuesday, April 25, 2023 | 4:00pm