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Cytosolic caspase-3-like proteases, such as caspase-3 and caspase-7, have a central role in mediating the progress of apoptosis. Here to conveniently monitor caspase-3-like activity in the multicellular environment, we have developed genetically encoded switch-on fluorescence-base indicators that are cyclized chimeras containing a caspase-3 cleavage site as a switch. When cleaved by caspase-3-like proteases, the non-fluorescent indicator rapidly becomes fluorescent, and thus detects in real-time the activation of such caspases. We generate cultured cells constitutively expressing these chimeras, and all the healthy cells are non-fluorescent. When these cells are exposed to apoptotic stimuli, dead cells show strong fluorescence depending on caspase activation. With these tools, we monitor in real-time caspase-3-like activity in each cell under various conditions, and show for the first time that the environment of cancer cells affects their sensitivity to chemotherapeutic drugs in a modified soft agar assay. These biosensors should enable better understanding of the biological relevance of caspase-3-like proteases.

The effects of milk fat concentration on flavor perception of vanilla ice cream (with 0.5 to 10% fat) were studied by sensory analyses. The percentage of free vanillin in the ice cream was determined by HPLC. The HPLC data showed that the amount of free vanillin decreased when fat content increased. Perceptions of vanilla flavor and sweetness were evaluated by a trained panel using time-intensity methodology. No significant difference was found in sweetness perception. Among 11 time-intensity parameters for vanilla flavor perception, the panel found a significant difference only in the time required to reach maximum vanilla intensity. However, free-choice profiling and a consumer preference panel showed, respectively, that, as fat content was increased, sensory quality improved, and overall preference increased.

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