Isolation of γ‑Glutamyl-Transferase Rich-Bacteria from Mouse Gut by a Near-Infrared Fluorescent Probe with Large Stokes Shift

• Published in: Analytical chemistry (Washington) 2018-08, Vol.90 (16), p.9921-9928
• Main Authors: Liu, Tao, Yan, Qiu-Long, Feng, Lei, Ma, Xiao-Chi, Tian, Xiang-Ge, Yu, Zhen-Long, Ning, Jing, Huo, Xiao-Kui, Sun, Cheng-Peng, Wang, Chao, Cui, Jing-Nan
• Format: Article
• Language: English
• ISSN: 0003-2700; 1520-6882
• DOI: 10.1021/acs.analchem.8b02118

Bacterial γ-glutamyltranspeptidases (γ-GT) is a well-known metabolic enzyme, which could cleave the γ-glutamyl amide bond of γ-glutamyl analogues. As a key metabolic enzyme of bacteria and a virulence factor for the host, bacterial γ-GT was determined to be a novel pharmaceutical target for new antibiotics development. However, there is no efficient method for the sensing of γ-GT activity in bacteria and the recognition of γ-glutamyltransferase rich-bacteria. In the present work, a dicyanoisophorone derivative (ADMG) has been designed and developed to be a sensitive and selective near-infrared fluorescent probe for the sensing of bacterial γ-GT. ADMG not only sensed bacterial γ-GT in vitro, but also imaged intestinal bacteria in vivo. More interesting, the intestinal bacteria existed in the duodenum section of mouse displayed significant fluorescence emission. Under the guidance of the sensing of γ-GT using ADMG, three intestinal bacteria strains K. pneumoniae CAV1042, K. pneumoniae XJRML-1, and E. faecalis were isolated successfully, which expressed the bacterial γ-GT. Therefore, the fluorescent probe ADMG not only sensed the endogenous bacterial γ-GT and imaged the intestinal bacteria but also guided the isolation of intestinal bacteria possessing γ-GT efficiently, which suggested a novel biological tool for the rapid isolation of special bacteria from a mixed sample.