In this work we have applied in situ hybridization with alphoid centromeric probes specific to chromosomes 7 and 11 to ana-telophase cells from human primary fibroblasts. The aim was to visualize the events leading to aneuploidy directly during anaphase, analyse the induction of aneuploidy during this mitotic stage and compare the frequencies of chromosome malsegregation observed in ana-telopha...

1. Colchicine and vincristine only slightly inhibit the metabolism of glucose to CO(2) and lipids by isolated fat-cells. 2. Prolonged incubation with these agents causes no further inhibition. 3. Cytochalasin B, however, inhibits glucose metabolism to both CO(2) and lipids in fat-cells. 4. However, at a concentration that causes a strong inhibition of glucose metabolism cytochalasin B is withou...

The cytochalasins stimulate steroid secretion of Y-1 adrenal tumor cells two-to threefold. The order of potencies is cytochalasin E is greater than D is greater than B, but the maximum response is the the same and always less than with ACTH. Like that with ACTH, the stimulation has a rapid onset, is easily reversible, is inhibited by cucloheximide and aminoglutethimide, and occurs at a stage be...

ACTH inhibits DNA synthesis in normal rat and mouse tumor Y-1 adrenocortical cells within the same concentration range that it stimulates steroidogenesis. These processes can be independently regulated as demonstrated by the divergent actions of cytochalasin B on these cells. In the normal cells, cytochalasin B does not increase steroidogenesis in serum-free or serum-containing media, and it de...

Cytochalasin B prevents both migration and wound-associated replication when applied to wounded monolayers of bovine endothelium in tissue culture. The normal low background rate of replication in undisturbed areas of the cultures is not inhibited by cytochalasin B. These results suggest that some form of movement may be required for initiation of wound-associated replication by endothelial cells.

Cytochalasin B produces multinucleated erythroid cells in tissue cultures of very young chick blastoderms. There is no apparent qualitative interference with differentiation and maturation of erythroid cells, but the amounts produced are reduced 4- and 10-fold. These effects of cytochalasin are readily reversible.

We determined the distribution of F-actin in fucoid (Pelvetia, Fucus) embryos with nitrobenzoxadiazole-phallacidin, and studied the effect of cytochalasin upon the endogenous currents associated with cell polarization by using the vibrating probe. F-actin is not localized at the presumptive rhizoid immediately after experimental induction of the polar axis with a light gradient; however, a pref...

The plasma membrane glucose transporter of Leishmania donovani, an obligate intracellular protozoan parasite of humans, was specifically labeled, identified, and biochemically characterized. Cytochalasin B, a known inhibitor of D-glucose transport in mammalian cells, but not cytochalasin E inhibited the transport of 2-deoxy-D-glucose in the extracellular promastigote form of this organism. Hydr...

To examine the relationship between binding of surface-active stimuli to human neutrophils and activation of the superoxide (02. ) and peroxide (H202) forming oxidase(s) of these cells. oxygen (02) consumption and 02. and H202 release were measured following stimulation by plant lectins. Both concanavalin A (Con-A) and phytohemagglutinin (PHA) were more active than other lectins in stimulating ...