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

Anal Chem. 2018 Aug 21;90(16):9921-9928. doi: 10.1021/acs.analchem.8b02118. Epub 2018 Aug 1.

Abstract

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Bacteria / isolation & purification*
  • Bacterial Proteins / analysis*
  • Bacterial Typing Techniques / methods*
  • Cyclohexanones / chemical synthesis
  • Cyclohexanones / chemistry
  • Enterococcus faecalis / isolation & purification
  • Fluorescent Dyes / chemical synthesis
  • Fluorescent Dyes / chemistry*
  • Gastrointestinal Microbiome*
  • Glutamates / chemical synthesis
  • Glutamates / chemistry
  • Klebsiella pneumoniae / isolation & purification
  • Mice
  • Microscopy, Confocal
  • gamma-Glutamyltransferase / analysis*

Substances

  • Bacterial Proteins
  • Cyclohexanones
  • Fluorescent Dyes
  • Glutamates
  • gamma-Glutamyltransferase