geoscience.net logo
+ Resolve Article
+ Follow Us
Follow on FacebookFollow on Facebook
Follow on TwitterFollow on Twitter

+ Translate
+ Subscribe to Site Feed
GeoScience Most Shared ContentMost Shared Content

Endo-lysosomal acidification in Dictyostelium discoideum amoebae. Effects of two endocytosis inhibitors: caffeine and cycloheximide


, : Endo-lysosomal acidification in Dictyostelium discoideum amoebae. Effects of two endocytosis inhibitors: caffeine and cycloheximide. European Journal of Cell Biology 61(2): 225-228

Fluid-phase endocytosis (pinocytosis) is highly active in amoebae of the cellular slime mould Dictyostelium discoideum as it provides an efficient entry of nutrients in axenic strains. Detailed kinetic analyses were conducted using fluorescein-labeled dextran (FITC-dextran) as fluid-phase marker and pH probe. Cells were first pulsed with FITC-dextran during a short period then chased by suspension in probe-free medium. Chase kinetics were characterized by a lag phase of about 40 min before pseudo-first order FITC-dextran efflux and thus reflected the progression of the probe cohort through the various endosomal compartments along the endosomal pathway. Temporal evolution of endo-lysosomal pH showed a rapid acidification (T1/2 approximately 10 min) to pH 5.0 followed by an increase up to pH 6.2 to 6.3. The effects of cycloheximide and caffeine, two inhibitors of endocytosis in Dictyostelium amoebae, on the evolution of endosomal pH during fluid-phase endocytosis, have been investigated. Cycloheximide fully blocked the cellular transit of FITC-dextran but acidification of endo-lysosomal compartments still took place. Caffeine increased endo-lysosomal pH, probably as a consequence of an elevation of cytosolic [Ca2+]. Furthermore, it allowed the functional identification of a caffeine-insensitive terminal segment of the endocytic pathway. It corresponded to a recycling, postlysosomal compartment at pH 6.2 to 6.3 with an apparent volume of 160 microns 3/amoebae.

US$29.90

PMID: 7693471


Other references

Moguel-Ancheita, S.; Orozco-Gómez, L.Porfirio., 2008: Neuronal and psychomotor malfunction secondary to delayed amblyopia treatment. A review of neuronal and psychomotor alterations related to delay of amblyopia treatment was carried out. We reviewed various studies to explain the anomalies of visual cortex because of the prevalence of anomalous stimulus in patients with amblyo...

Bohatyrewicz, A., 2001: Bone fluoride in proximal femur fractures. Bone fluoride concentration and bone mineral density (BMD) were evaluated in 51 female patients who had undergone hip arthroplasty due to proximal femur fracture. The hip fractures were divided into 42 neck and head fractures and 9 trochanteric fr...

Sawhney, C.; Kaur, M.; Lalwani, S.; Gupta, B.; Balakrishnan, I.; Vij, A., 2013: Organ retrieval and banking in brain dead trauma patients: Our experience at level-1 trauma centre and current views. Organ retrieval from brain dead patients is getting an increased attention as the waiting list for organ recipients far exceeds the organ donor pool. In our country, despite a large population the number of brain dead donors undergoing organ donat...

Zhen, X.; Wang, S.; Zhou, Y.; Zhu, Z., 1997: The change in renal blood flow in the early diabetic nephropathy. Diabetologia 40(SUPPL 1): A531

Reddy, P.S.; Zade, V.R.; Deshmukh, S.N., 1985: CGS1-19: a new Spanish bunch groundnut cultivar with fresh seed dormancy. CGS1-19, derived from the cross J11 X Robut 33-1, showed 6% seed germination 10 days after sowing and 26% 35 days after sowing, comparable figures for 17 other Spanish and Valencia type varieties being 37-71% and 55-91%, respectively. CGS1-19 has...

Grigorova Ek ); Glavcheva R., 1979: Seismicity of Bulgaria, 1965-1970. B"lgarsko Geofizichno Spisanie = Bulgarian Geophysical Journal 5(4): 40-51

Tikhomirov V.N., 1983: New species of the genus alchemilla from mongolia. Two new species are described from the I. A. Gubanov's collection in Hangai: A. changaica and A. gubanovii, A. austroaltaica nom. nov., is proposed for the invalid A. pavlovii Rothmaler non Juz.

Siebeneick, H., 1936: Studies on the inheritance of milk and fat yield among the progeny of the bull Mozart 4622 in the Province of Saxony. UP to 1935 the Black-and-White Lowland bull " Mozart 4622 " has given an exceptionally large number of descendants, the total for 3 generations being 340 bulls and 695 cows. From a comparison of 30 dam-daughter pairs, a sire index of 450...

Chang, L.C.ee; Otero Quintero, S.; Nicholas, G.M.; Bewley, C.A., 2001: Phyllolactones A-E: New bishomoscalarane sesterterpenes from the marine sponge Phyllospongia lamellosa. Five new bishomoscalarane sesterterpenes, phyllolactones A-E (1-5), have been isolated from the marine sponge Phyllospongia lamellosa. The structures were elucidated by 1D and 2D 1H and 13C NMR, unambiguous assignments of overlapping 1H and 13C re...

Faki, H.H.M.; Nourai, A.H., 1991: Prospects of lentil introduction in farming systems of the arid region of northern Sudan. On-farm trials were conducted in Rubatab area of the Nile Province of northern Sudan during 1983/84 and 1984/85, continuing in 1988/89. The objectives were to identify problems associated with the large-scale production of lentils, to estimate the...