title: Amyloid histology stain for rapid bacterial endospore imaging.
abstract: Bacterial endospores are some of the most resilient forms of life known to us, with their persistent survival capability resulting from a complex and effective structural organization. The outer membrane of endospores is surrounded by the densely packed endospore coat and exosporium, containing amyloid or amyloid-like proteins. In fact, it is the impenetrable composition of the endospore coat and the exosporium that makes staining methodologies for endospore detection complex and challenging. Therefore, a plausible strategy for facile and expedient staining would be to target components of the protective surface layers of the endospores. Instead of targeting endogenous markers encapsulated in the spores, here we demonstrated staining of these dormant life entities that targets the amyloid domains, i.e., the very surface components that make the coats of these species impenetrable. Using an amyloid staining dye, thioflavin T (ThT), we examined this strategy. A short incubation of bacillus endospore suspensions with ThT, under ambient conditions, resulted in (i) an enhancement of the fluorescence of ThT and (ii) the accumulation of ThT in the endospores, affording fluorescence images with excellent contrast ratios. Fluorescence images revealed that ThT tends to accumulate in the surface regions of the endospores. The observed fluorescence enhancement and dye accumulation, coupled with the sensitivity of emission techniques, provide an effective and rapid means of staining endospores without the inconvenience of pre- or posttreatment of samples.
authors.affiliation: Department of Bioengineering, University of California, Riverside, 900 University Avenue, Riverside, CA 92521, USA.
authors.forename: Bing
authors.initials: B
authors.lastname: Xia
authors.forename: Srigokul
authors.initials: S
authors.lastname: Upadhyayula
authors.forename: Vicente
authors.initials: V
authors.lastname: Nuñez
authors.forename: Pavel
authors.initials: P
authors.lastname: Landsman
authors.forename: Samuel
authors.initials: S
authors.lastname: Lam
authors.forename: Harbani
authors.initials: H
authors.lastname: Malik
authors.forename: Sharad
authors.initials: S
authors.lastname: Gupta
authors.forename: Mohammad
authors.initials: M
authors.lastname: Sarshar
authors.forename: Jingqiu
authors.initials: J
authors.lastname: Hu
authors.forename: Bahman
authors.initials: B
authors.lastname: Anvari
authors.forename: Guilford
authors.initials: G
authors.lastname: Jones
authors.forename: Valentine I
authors.initials: VI
authors.lastname: Vullev
mesh_terms: D001407:Bacillus / Q000166:cytology; D001426:Bacterial Proteins / Q000378:metabolism*; D001431:Bacteriological Techniques / Q000379:methods*; D052160:Benzothiazoles; D001411:Geobacillus stearothermophilus / Q000166:cytology; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008856:Microscopy, Fluorescence / Q000379:methods; D013171:Spores, Bacterial / Q000166:cytology*; D013194:Staining and Labeling / Q000379:methods*; D013844:Thiazoles / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D052160:Benzothiazoles; D013844:Thiazoles; C009462:thioflavin T