Some characteristics of membrane Cd2+ transport in rat thymocytes: an analysis using Fluo-3

Identification of two bitter components in Zanthoxylum bungeanum Maxim. and exploration of their bitter taste mechanism through receptor hTAS2R14

Bitterness is an inherent organoleptic characteristic affecting the flavor of Zanthoxylum bungeanum Maxim. In this study, the vital bitter components of Z. bungeanum were concentrated through solvent extraction, sensory analysis, silica gel chromatography, and thin-layer chromatographic techniques and subsequently identified by UPLC-Q-TOF-MS. Two components with the highest bitterness intensities (BIs), such as 7-methoxycoumarin and 8-prenylkaempferol were selected. The bitter taste perceived thresholds of 7-methoxycoumarin and 8-prenylkaempferol were 0.062 mmol/L and 0.022 mmol/L, respectively. Moreover, the correlation between the contents of the two bitter components and the BIs of Z. bungeanum were proved. The results of siRNA and flow cytometry showed that 7-methoxycoumarin and 8-prenylkaempferol could activate the bitter receptor hTAS2R14. The results concluded that 7-methoxycoumarin and 8-prenylkaempferol contribute to the bitter taste of Z. bungeanum.

Selenoprotein SELENOK Enhances the Migration and Phagocytosis of Microglial Cells by Increasing the Cytosolic Free Ca2+ Level Resulted from the Up-Regulation of IP3R

Enhancing the migration and phagocytosis of microglial cells is of great significance for the reducing of the risk of the neurodegenerative diseases, such as Alzheimer's disease (AD) and Parkinson's disease (PD). The effect of mouse selenoprotein K (mSELENOK) on the migration and phagocytosis of BV2 microglial cells and its mechanism were studied. The results showed that the over-expression of mSELENOK can increase the migratory and phagocytic abilities of the microglial cells, while the knockdown of mSELENOK can decrease the migratory and phagocytic abilities of the cells. The cytosolic free Ca²⁺ level and inositol trisphosphate receptor (IP₃R) mRNA transcript and protein expression were also increased significantly as the consequence of the over-expression of mSELENOK in the microglial cells. On the contrary, the level of cytosolic free Ca²⁺ and the mRNA transcript and protein expression of IP₃R in mSELENOK knockdown cells were decreased significantly. 2-aminoethoxydiphenyl borate (2-APB), an antagonist of IP₃R, could prevent the increased migration, phagocytosis, and cytosolic free Ca²⁺ level of mSELENOK over-expressed microglial cells, and knockdown of IP₃R₃ could reduce the increased cytosolic Ca²⁺ level in mSELENOK over-expressed microglial cells. Further studies revealed that selenium supplement (Na₂SeO₃) can increase the expression of mSELENOK in microglial cells significantly. In summary, these data suggest that mSELENOK can increase cytosolic free Ca²⁺ level of microglial cells by up-regulating the expression of IP₃R, thus enhancing the migration and phagocytosis of microglial cells. Our results indicated that mSELENOK is an important selenoprotein, which plays a role in trace element selenium's functions and can enhance the migration and phagocytosis of microglial cells.

Physiological differences in the crab Ucides cordatus from two populations inhabiting mangroves with different levels of cadmium contamination

Crustaceans found in metal-contaminated regions are able to survive, and the authors investigated the physiological mechanisms involved by comparing populations from contaminated and noncontaminated areas. The objective of the present study was to measure the cellular transport of a nonessential metal (cadmium [Cd]) in gills and hepatopancreas of Ucides cordatus, together with cell membrane fluidity, metallothionein levels, and lipid peroxidation. The 2 populations compared were from a polluted and a nonpolluted mangrove area of São Paulo State, Brazil. The authors found, for the first time, larger Cd transport in gills and hepatopancreatic cells from crabs living in polluted mangrove areas. The cells also had lower plasma membrane fluidity, increased lipid peroxidation and less metallothionein compared to those from nonpolluted regions. The authors also found larger amounts of Cd in intracellular organelles of gills, but not in the hepatopancreas, from crabs in polluted regions. Therefore, in polluted areas, these animals showed higher Cd transport and lower plasma membrane fluidity and storage of Cd intracellularly in gill cells, whereas hepatopancreatic cells used metallothionein as their main line of defense. The findings suggest that crabs from polluted areas can accumulate Cd more easily than crabs from nonpolluted areas, probably because of an impairment of the regulatory mechanisms of cell membrane transport. Environ Toxicol Chem 2017;36:361-371. © 2016 SETAC.