Recently, Liu Bo, a professor at the School of Biomedical Engineering at Dalian University of Technology, made a breakthrough in the visualization of cell membrane tension. The results of the study for the first time realized the dynamic visualization of cell membrane tension, and proved that the change of cell polarity under directional stress is not caused by the non-uniform distribution of cell membrane tension, but should be caused by the non-uniform transmission of force by other structures under the cell membrane. .
Liu Bo team used fluorescence resonance energy transfer technology to construct a tension detection probe that can specifically bind to lipid rafts and non-lipid rafts on cell membranes. The probe can visually observe the dynamic process of cell membrane tension under shear stress in living cells with an accuracy of pN.
Mechanical force plays an important role in the directional migration and polarity changes of cells, but the mechanism of its polarity is still unclear. Professor Liu Bo hypothesized that this polarity is caused by external stress being transmitted directly to a specific location within a cell along a specific structure, causing local protein activation. Cell membrane is the primary link of stress transmission, and the uneven distribution of tension distribution may be the source of cell polarity change. However, this assumption has not been validated due to the lack of suitable probes. Although the traditional microtubule sucking technique, aperture, and magnetic enthalpy can measure the surface tension of cells, the information of the tension change cannot be provided in real time, and the spatial resolution is relatively poor.
In view of the above difficulties, the team further expanded the research of Nobel Prize-winning chemistry winner Qian Yongjian, embedding a spider silk protein with pN sensitivity between two fluorescent proteins to form a FRET probe that can be anchored to the cell membrane. Using this probe, it was found that under the action of the directed shear stress, the cell membrane tension showed a small non-uniform distribution with small ends and a large middle, and the membrane tension became larger as the fluidity of the cell membrane increased and the microfilament skeleton destroyed. However, there will be no difference in polarity between upstream and downstream.
It is reported that the research work was funded by the National Natural Science Foundation of China (31670867, 31670961) and the basic research business fee of the Central University (DUT15LK16). Li Wang, the master student of the School of Biomedical Engineering, Dalian University of Technology, was the first author of the paper. Professor Liu Bo Corresponding author of the article. (Hu Xin)
Source: People's Network
Anthocyanins widely exist in flowering plants (angiosperms), and their content in plants varies greatly with varieties, seasons, climate and maturity[ 5] According to preliminary statistics, anthocyanins are contained in 27 families and 73 genera, such as purple sweet potato, grape, blood orange, red ball cabbage, blueberry, eggplant, cherry, red berry, strawberry, mulberry, hawthorn, morning glory and other plant tissues. Anthocyanins are mainly used in food coloring, dyes, medicine, cosmetics and so on.
Application
Antioxidant and free radical scavenging function
Anthocyanins belong to bioflavonoids, and the main physiological functions of flavonoids are free radical scavenging ability and antioxidant ability. Studies have proved that anthocyanins are the most effective antioxidants and the most powerful free radical scavengers found by human beings. The antioxidant performance of anthocyanins is 50 times higher than that of VE and 20 times higher than that of VC. Purple Sweet Potato Anthocyanin products can scavenge and inhibit - Oh, H2O2 and other reactive oxygen species, especially - Oh is stronger than ascorbic acid, and the scavenging effect is dose-dependent with concentration.
Anti mutation function
The function of anthocyanins not only makes plants present colorful colors, but also active molecules with health functions such as reducing enzyme activity and anti mutation. Studies have shown that the extract with a certain concentration of anthocyanin can effectively prevent carcinogenesis at different stages, but the individual role of anthocyanin is uncertain, partly because anthocyanin is easy to degrade after bioassay after separation from other stable components such as phenols.
Application in food
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