Chapter 14 Measurement of Material Uptake by Cells: Pinocytosis

Nutrient uptake in Tetrahymena pyriformis

“…It is regrettable that our knowledge of food uptake at levels different from those of the phagocytic vesicles in T. pyriformis is so scanty, when compared to our knowledge of pinocytosis in the large amoebae. Here extensive and fruitful studies have revealed the importance of adsorption of charged molecules, the existence of inducers of pinocytosis, and the timing and the extent of the uptake of both high-and low-molecular weight compounds: for reviews see HOLTER (44,45,46) and CHAP-MAN-ANDRESEN (7,8,9) (105)). The outer membrane, the plasma membrane, covers the entire surface of the cell, also the cilia; immediately beneath the plasma membrane is a mosaic of flat, membrane-bounded ~alveoli,,; cilia and mucocysts emerge from the underlying ectoplasm between adjacent alveoli (PITELKA (75)).…”

Absorption of Macromolecules by Neonatal Intestine

“…T hese an im als o b ta in im m u n o g lo b u lin from th e ir d am b o th pre-and p o stn a ta lly . T he p o st n a ta l a b so rp tio n phase in th is g ro u p is ex ten d ed , la stin g for 10 d ay s (dogs) to 20 d ay s (ra ts).D u rin g th is e a rly p h ase w hen m acrom olecules can be absorbed, p re su m a b ly th e n e o n a te 's in te s tin a l e p ith eliu m is n o t y e t m a tu re a n d a b so rp tio n ta k e s place b y a p rim itiv e m echanism sim ilar to th a t fo u n d in m acro p h ag es, p la n a ria a n d am o eb a [5,6]. T his m echanism is called p in o c y to sis-th a t is, cell d rin k in g , accom plished b y the folding an d in te rio riz in g o f th e cell's su rface m em b ran e. In fo rm a tio n concerning th is n e o n a ta l tra n s p o rt sy stem for m acrom olecules u su ally falls in to 2 c a te g o rie s: (1) specificity o f a b s o rp tio n ; (2) cessation of a b so rp tio n (closure).…”

The early days of pinocytosis

“…For basic dyes, the conditions were similar to those shown by protein inducers. Finally, in a small group of compounds, so far comprising the copper phthalocyanin dye alcian blue, and rhuthenium red, the dye, once bound to the surface, remained firmly attatched despite all possible changes in pH or ionic strength of the medium, that living amoebae could tolerate (9,10). The second phase of pinocytosis, the active phase of channel formation, which followed rapidly after surface binding, was dependent of temperature, and sensitive to inhibitors ofglycolysis and oxidative phosphorylation (11).…”