Transferrin receptor mediates internalization of transferrin with bound ferric ions through the clathrindependent
pathway. We found that binding of transferrin to the receptor induced rapid generation of cell
surface ceramide which correlated with activation of acid, but not neutral, sphingomyelinase. At the onset
of transferrin internalization both ceramide level and acid sphingomyelinase activity returned to their
basic levels. Down-regulation of acid sphingomyelinase in cells with imipramine or silencing of the enzyme
expression with siRNA stimulated transferrin internalization and inhibited its recycling. In these
conditions colocalization of transferrin with clathrin was markedly reduced. Simultaneously, K+ depletion
of cells which interfered with the assembly of clathrin-coated pits inhibited the uptake of transferrin
much less efficiently than it did in control conditions. The down-regulation of acid sphingomyelinase activity
led to the translocation of transferrin receptor to the raft fraction of the plasma membrane upon
transferrin binding. The data suggest that lack of cell surface ceramide, generated in physiological conditions
by acid sphingomyelinase during transferrin binding, enables internalization of transferrin/transferrin
receptor complex by clathrin-independent pathway.

In the present study, the effect of modulation of autophagy induced by
anthocyanin on cell death of Human T lymphoma cells (Jurkat) was studied.
Anthocyanin was abstracted from dry petals of Hibiscus sabdariffa, aquous solution
of anthocyanin was added to cells at different concentrations then cell viability was
determined by trypan blue exclusion method. Autophagy induced by anthocyanin was
inhibited by 5 mM NH4CL which halts lysosomal enzymes and accordingly
preventing autolysosomes formation. On the other hand, Autophagy was enhanced by
glucose starvation. In both experiments of autophagy inhibition and enhancement, cell
viability was studied to investigate the effect of autophagy modulation on cell viability.
The results of this work revealed that both inhibition and enhancement of autophagy induced
by anthocyanin lead to massive cell death. Immuno-detection of active caspase 3, one of the
major hallmark of apoptotic cell death revealed remarkable increase of active caspse3 upon
autophagy inhibition or enhancement. In conclusion, modulation of autophagy induced by
anthocyanin lead to increasing of apoptotic cell death.

The differential thermal analysis (DTA) is utilized to determine the phase boundary and phase equilibria of Co-Cu alloy having a miscibility gap. Regions for various phase i.e., spinodal and coherent binodal, peritectic, magnetic and the transformation from the two phases to phase transformations are distinctly determined for the Co-13 at%Cu alloy. The obtained results might indicate the continuity of the decomposition kinetics at the boundary between instable and the metastable regions but an activation barrier is needed. The activation energy for the magnetic transformation is determined to be 182.2 ± 2.1 kJ mol-1.

The differential thermal analysis (DTA) is utilized to determine the phase boundary and phase equilibria of Co-Cu alloy having a miscibility gap. Regions for various phase i.e., spinodal and coherent binodal, peritectic, magnetic and the transformation from the two phases to phase transformations are distinctly determined for the Co-13 at%Cu alloy. The obtained results might indicate the continuity of the decomposition kinetics at the boundary between instable and the metastable regions but an activation barrier is needed. The activation energy for the magnetic transformation is determined to be 182.2 ± 2.1 kJ mol-1.