Figure 3.

Intravital Ca²⁺ signaling images mediated by probiotics in the intestinal tract of a mouse under ubiquitous YC3.60 expression. (A) Representative Ca²⁺ signaling images in the intestinal tract of a mouse under ubiquitous YC3.60 expression and specific pathogen-free (SPF) conditions. Ratiometric images [yellow fluorescent protein (YFP)/cyan fluorescent protein (CFP) at excitation of 458 nm] are shown. The 0.1 ml of Bacillus subtilis natto in PBS (10⁹ cells/ml) was added at the indicated time point. A rainbow parameter indicates relative Ca²⁺ concentration. (B) Time course for fluorescence intensities of YFP/CFP on excitation at 458 nm. Randomly selected regions (n = 10) were measured. Scale bar, 50 µm; frame = 151. Spontaneous Ca²⁺ signals are indicated by arrows. (C) Distribution of time-integrated intracellular Ca²⁺ concentrations of randomly selected regions before (upper panel) and after (lower panel) stimulation; n = 10. (D) Representative Ca²⁺ signaling images in the intestinal tract of a mouse under ubiquitous YC3.60 expression and SPF conditions. Ratiometric images (YFP/CFP at excitation of 458 nm) are shown. The 0.1 ml of Lactococcus lactis in PBS (10⁹ cells/ml) was added at the indicated time point. (E) Time course for fluorescence intensities of YFP/CFP on excitation at 458 nm; frame = 85. (F) Distribution of time-integrated intracellular Ca²⁺ concentrations of randomly selected regions; n = 10. Shown are representative results from three mice.