Question

Which type of microscopy would be best to visualize and count the GFP-tagged E. coli cells adhering to macrophages, as described on the previous page? Choose from: phase contrast, brightfield, fluorescence microscopy, transmission electron microscopy, or scanning electron microscopy. Explain your answer.

Answer 1

fluroscence microscopy would be best to visualize and count the GFP tagged E.coli cells adhering to macrophages.

it is widely used and very sensetive method for studying intracellular distribution of molecules.a fluroscent dye is used to label the molecule of interest within either fixed or living cell.the fluroscent dye is a molecule that absorbs light at one wavelength and emits light at a second wavelength.this fluroscence is detected by illuminating the specimen with a wavelength of light that excites the fluroscent dye and then using appropriate filters to detect the specific wavelength of light that dye emits.proteins in living cells can be visualized by using Green Fluroscent Protein.

macrophages play key role in tissue homeostasis as well as pathological conditions including atherosclerosis,autoimmunity and cancer.imaging with GFP could potentially offer powerfull tool to study macrophage cell.in diseased conditions no. of macrophages increases.

E.coli labelled with GFP the bacteria shows bright green fluroscence. PAMs can competitively bind to opsonized E. coli adhered to surface of cells like erythrocytes,and these opsonized pathogens can enter macrophages by process of phagocytosis, promoting internalization of pathogens.

confocal microscopy also used to visualize and count GFP tagged E.coli cells adhering to macrophages.