Anti-CD6 monoclonal antibody, clone 07234 [Biotin]

The dynamics of cell surface membrane proteins plays an important role in cell-cell interactions. The onset of the interaction is typically not precisely controlled by current techniques, making especially difficult the visualization of early-stage dynamics. We have developed a novel method where optical tweezers are used to trap cells and precisely control in space and time the initiation of interactions between a cell and a functionalized surface. This approach is combined with total internal reflection fluorescence microscopy to monitor dynamics of membrane bound proteins. We demonstrate an accuracy of similar to 2 s in determining the onset of the interaction. Furthermore, we developed a data analysis method to determine the dynamics of cell adhesion and the organization of membrane molecules at the contact area. We demonstrate and validate this approach by studying the dynamics of the green fluorescent protein tagged membrane protein activated leukocyte cell adhesion molecule expressed in K562 cells upon interaction with its ligand CD6 immobilized on a coated substrate. The measured cell spreading is in excellent agreement with existing theoretical models. Active redistribution of activated leukocyte cell adhesion molecule is observed from a clustered to a more homogenous distribution upon contact initiation. This redistribution follows exponential decay behaviour with a characteristic time of 35 s.

By the method of polarizing microscopy, a chiral nematic phase formation of the 4-(n)alkoxy-4'-cyanobiphenyls (n = 3,4,5,6,7,8) nematic mixtures (CB6) was observed under the influence of 1R(+)1',7',7'-trimethylbicyclo[2.2.1]heptane[2',3'-b]-2,3-dicyanopyrazine (R(+) CDCP). The values of clearance temperature and pitch were measured and helical twisting power ([3) was calculated. The degree of racemic mixture ()CDCP and chiral R(+)CDCP destabilizing action on liquid crystalline phase was determined. As the result of birefringence and H-1 NMR splitting analysis, optical properties in nematic LC and quasinematic layers of chiral phase were established to depend on orientational order parameter. On the base of binary systems CB6 + R(+)CDCP and CD6+(+/-)CDCP permittivity and the dielectric anisotropy of achiral mixture were found to slightly depend on dopant concentration whereas in the case of helical mesophase the essential decrease in anisotropy with R(+)CDCP content rise was observed. As the result of Kirkwood's factor analysis and quantum-chemical calculation the polar dopant was shown to influence on LC associative state due to dipole-dipole interaction of R(+)CDCP with LC cyano group. (C) 2017 Elsevier B.V. All rights reserved.