Mice lacking the K+ channel Kir4.1 or both connexin32 (Cx32) and Cx47 exhibit myelin-associated vacuoles, raising the possibility that oligodendrocytes, and the connexins they express, contribute to recycling the K+ evolved during neuronal activity. To study this possibility, we first examined the effect of neuronal activity on the appearance of vacuoles in mice lacking both Cx32 and Cx47. The ...

The uneven distribution of Mg2+, K+, and phosphate in Saccharomyces carlsbergensis was demonstrated by the differential extraction of ions. Their concentrations were 5, 60, and 1 mM in the cytoplasm and 73, 470, and 110 mM in vacuoles, respectively. The intracellular gradients of these ions were 1:15, 1:8, and 1:110, respectively, across the tonoplast. The determination of free Mg2+ (1.35 mM in...

Aged cells have significantly fewer food vacuoles and ingest fewer bacteria than young cells. Loss of food vacuoles was explained by a decreasing difference in the food vacuole formation and excretion rates; the formation rate declined more rapidly than the excretion rate, approaching equivalence at 160 fissions, when the proportion of cells with no food vacuoles, in the presence of excess food...

Intracellular bacterial pathogens enter their hosts surrounded by a membrane-bound vacuole and use a panel of tricks to exploit or evade eukaryotic cell functions (9, 12). Chlamydia inhabits vesicles that do not fuse with lysosomes and remains within these parasitophorous vacuoles (termed inclusions) for the duration of its replication cycle. Although the biogenesis of these vacuoles is still p...

Very low density lipoprotein (VLDL) particles are packaged by the Golgi apparatus into vacuoles which move to the plasma membrane and empty the particles into the space of Disse, via exocytosis. Traditionally, all lipoprotein-containing cisternae and vacuoles are thought to be parts of this pathway. Observations reported here demonstrate that there is a second population of lipoprotein-containi...

[14C]Lactose electroinjected into isolated rat hepatocytes is normally autophagocytosed, transferred to lysosomes and degraded by lysosomal beta-galactosidase, but at high concentrations of asparagine the transfer is inhibited and lactose accumulates in prelysosomal autophagic/endocytic vacuoles (amphisomes). The accumulation can be prevented by addition of yeast beta-galactosidase, which is tr...

Human neutrophils sequester yeast cells or zymosan particles in two classes of phagocytic vacuoles: sealed and unsealed. The pH of sealed vacuoles was measured by a newly devised fluorometric procedure that used fluoresceinated zymosan particles, derived from Saccharomyces cerevisiae, as a pH probe. Five minutes after initiation of phagocytosis, sealed vacuoles were alkaline, exhibiting a pH of...

Toxoplasma gondii represents a pathogen that survives within host cells by preventing the endosomal-lysosomal compartments from fusing with the parasitophorous vacuoles. The dogma had been that the non-fusogenic nature of these vacuoles is irreversible. Recent studies revealed that this dogma is not correct. Cell-mediated immunity through CD40 re-routes the parasitophorous vacuoles to the lysos...

Vacuoles have diverse functions within all plant cells. Vacuoles get rid of wastes, accumulate nutrients, and regulate pressure within a cell. They are also known to store sugars. Many of the compounds within vacuoles are actively transported across the tonoplast membrane against a concentration gradient via transporters. The identification of transporters involved in vacuolar Suc transport was...

Plant vacuoles are essential organelles for plant growth and development, and have multiple functions. Vacuoles are highly dynamic and pleiomorphic, and their size varies depending on the cell type and growth conditions. Vacuoles compartmentalize different cellular components such as proteins, sugars, ions and other secondary metabolites and play critical roles in plants response to different b...