A novel sweet taste cell-based sensor.

In this paper, a novel sweet taste cell-based sensor is proposed for tastants detection. The human colorectal carcinoma NCI-H716 cell lines, which express α-gustducin and sweet taste receptor T1R1/T1R3, are cultured on the carbon screen-printed electrode with the pre-coated poly-L-ornithine and lamimin for adhesion in extracellular matrix. The electrode is placed into a fluidic and environment regulation system. When stimulated by an electric field at a fixed frequency of 1 kHz and 10 µA, the electrochemical impedance spectrum data was recorded by EG&G 273A and high performance dual phase analog lock-in amplifier 5210 and processed by bistable stochastic resonance method. Four basic tastants and sucrose solutions in seven concentrations can be decided by maximums of the signal-to-noise ratio and relevant noise intensity. A negative control experiment utilizing COLO-205 cell lines demonstrate that carbon screen-printed electrode with mammalian cell line without the expression of gust TIR2 and TIR3 lacked the tastant detecting ability. The sensor system presents good stability and repeatability. The proposed sensor is promising for practical applications, and provides a novel way for taste mechanism investigation.

A reliable method to obtain cells of taste buds from fungiform papillae of mice.

Taste buds consist of four kinds of cells which have distinct characteristics and play different roles in recognizing chemical compounds contained in foodstuffs. In this study we describe a procedure for separating viable taste bud cells from the fungiform papillae in mice. After sacrifice with CO(2), the mouse tongue was excised and immediately incubated in collagenase II and dispase II. The epithelium with fungiform papillae was then peeled away from underlying tissue and the anterior one-third region was incubated in a solution of 0.25% trypsin and 0.02M ethylene-diamine-tetraacetic acid (EDTA) for 8-12min. Following incubation, a cell suspension was obtained by mechanical dissociation. Cells in suspension were identified as taste bud cells by their morphology and by immunofluorescence. A 0.25% trypan blue staining demonstrated that nearly 90% of these cells remained viable. Micrographs from scanning electron microscopy illustrated that taste buds were dissociated from the fungiform papillae, while maintaining the integrity of the other part of the dissociated lingual epithelium during incubation. Such a method allows acquisition of viable taste cells and will aid further research in the study of gustatory characteristics.

Quantitative study of taste bud distribution within the oral cavity of the postnatal mouse.

The aim of this study was to investigate the age-related developmental changes of taste bud distribution within the subpopulations at different postnatal ages in the mouse oral cavity. Developmental changes of taste bud distribution on the soft palate, fungiform, foliate and circumvallate papillae in the mouse oral cavity were examined histologically at different postnatal ages. After paraffin embedding, complete serial sections at 10mum thickness were made and stained by routine hematoxylin-eosin staining methods. Digitised images for each section were examined carefully. The existence of a taste pore was used to identify mature taste buds. A two-way analysis of variance (group versus age) was used to analyse differences in taste bud number and characteristics for each of the developmental changes. An independent measures t-test was used to compare two means. No taste buds with pores were observed at birth within circumvallate and foliate papillae. However, 61% of the circumvallate and 58% of the foliate taste buds contained taste pores at 2 weeks after birth. In contrast, at birth, 55% of the taste buds on the soft palate and only 22% of the taste buds within fungiform papillae contained taste pores. Then, the number of mature taste buds (taste buds with pores) increased rapidly 1 week after birth, resulting in 90% of soft palate taste buds and 32% of fungiform taste buds containing taste pores. These results suggests that the earlier maturation of soft palate taste buds compared with the other populations in the oral cavity raises evidence of their significant role in the taste mechanism, especially in the early life of the mouse.