Mechanism of increased microbial autofluorescence by heat treatment

Abstract

Autofluorescence of bacteria and fungi was prominently intensified by heat treatment at 200°C. This phenomenon was associated with advanced glycation end products formed in micro-organisms via the Maillard reaction. The fluorescence signal was strong enough to be utilized as an alternative probe for fluorescent dye in the total direct count method. This phenomenon could be incorporated in an automatic apparatus for microbial enumeration, as it does not require staining.

Deep phenotypic characterization of immunization-induced antibacterial IgG repertoires in mice using a single-antibody bioassay

“…To reduce the impact of cellular heterogeneity 33 – 35 and to standardize the total amount of available antigens, we aimed to encapsulate at least a few hundred bacteria per droplet. The auto-fluorescence of HK-B 36 conveniently allowed to visualize the area of the bactoline, and to estimate the number of bacteria in the area (164 ± 30 HK-B per droplet). Since this calculation assumed the bacteria to be only present in a 2-dimensional sheet rather than a 3-dimensional bactoline, this number represented a lower limit of the number of bacteria that are present within a droplet.…”