The down- and up-shift responses of strain BIB1423, which expresses fluorescently tagged Ald-mCherry from its native promoter (Pald-ald-mCherry). At the onset of sporulation, cells that sporulate early have higher fluorescence levels than cells that delay sporulation due to dilution. The fluorescence is carried from the progenitors into the developing spore. Upon spore release, fluorescence drops due to unknown reasons and then remains stable. Early spores show higher fluorescence than late spores. All spores that grew out in response to L-alanine stimulation were circled. They all show higher levels of fluorescence compared to non-outgrowing spores.