Yeast CUP1 protects HeLa cells against copper-induced stress

As an essential trace element, copper can be toxic in mammalian cells when present in excess. Metallothioneins (MTs) are small, cysteine-rich proteins that avidly bind copper and thus play an important role in detoxification. Yeast CUP1 is a member of the MT gene family. The aim of this study was to determine whether yeast CUP1 could bind copper effectively and protect cells against copper stress. In this study, CUP1 expression was determined by quantitative real-time PCR, and copper content was detected by inductively coupled plasma mass spectrometry. Production of intracellular reactive oxygen species (ROS) was evaluated using the 2',7'-dichlorofluorescein-diacetate (DCFH-DA) assay. Cellular viability was detected using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, and the cell cycle distribution of CUP1 was analyzed by fluorescence-activated cell sorting. The data indicated that overexpression of yeast CUP1 in HeLa cells played a protective role against copper-induced stress, leading to increased cellular viability (P<0.05) and decreased ROS production (P<0.05). It was also observed that overexpression of yeast CUP1 reduced the percentage of G1 cells and increased the percentage of S cells, which suggested that it contributed to cell viability. We found that overexpression of yeast CUP1 protected HeLa cells against copper stress. These results offer useful data to elucidate the mechanism of the MT gene on copper metabolism in mammalian cells.

Discrimination of bile acids by the rainbow trout olfactory system: Evidence as potential pheromone

Electro-olfactogram recording was used to determine whether the olfactory epithelium of adult rainbow trout is specifically sensitive to bile acids, some of which have been hypothesized to function as pheromones. Of 38 bile acids that had been pre-screened for olfactory activity, 6 were selected. The rainbow trout-specific bile acids, taurocholic acid (TCA), and taurolithocholic acid 3-sulfate (TLS) were the most potent compounds tested. TLS had a distinctive dose-response curve. Cross-adaptation experiments demonstrated that sensitivity to bile acids is attributable to at least 3 independent classes of olfactory receptor sites. Our data suggest that bile acids are discriminated by olfaction in rainbow trout, supporting the possibility that these compounds function as pheromones.

Assessment of the influence of aging on the olfactory epithelium of rabbits: light and electron microscopic study

The present work was carried out to study the olfactory epithelium of rabbits in different ages and to compare age changes in the anterior and posterior areas of the olfactory mucosa. Twelve male Balady rabbits were used and they were divided equally into three age groups, group [1] 3 month old, group [2] 12 month old and group [3] 36 month old. The animals were sacrificed and the olfactory mucosa was peeled from two fixed parts in each group. Part 1: the posterior area of the roof of the nose and Part 2; the anterior upper area of the nasal septum. In group 1, the two examined parts of the olfactory mucosa were similar. The olfactory mucosa was composed of olfactory epithelium resting on a thin basal lamina and lamina propria that was characterized by the presence of Bowman's glands. The olfactory epithelium was composed of olfactory receptor neurons, supporting cells, microvillar cells that occupied the upper and the middle zones of the epithelium and basal cells in the basal zone of the epithelium. In group2, some degenerative changes were encountered in the olfactory epithelium of the two parts, but the anterior part was more affected than the posterior part. In the posterior part, the thickness of the epithelium and the cell population appeared within normal. However, in the anterior part, the thickness of the epithelium and the cell population demonstrated significant decrease. In group3, there were more degenerative changes than those of group 2. The olfactory mucosa from both parts suffered equally from severe degeneration. The most striking feature was replacement of wide areas of the olfactory epithelium with respiratory epithelium. Other areas showed many degenerated cells with significant reduction in the thickness of the epithelium. The presence of Bowman's glands was still characteristic to the olfactory epithelium. From the present study, it could be concluded that the olfactory epithelium was subjected to natural degenerative changes, which increased steadily with age. These changes began firstly in the anterior exposed areas of the epithelium and with the progress of age both areas were equally affected