The mode of action of cytochalasin B was examined in vitro using bile canaliculus-enriched plasma membrane fractions isolated from rat liver. The pericanalicular microfilaments, which are mainly actin filaments and which are normally attached to the canalicular membranes, were dissociated from the membranes by cytochalasin B treatment. A microfilamentous network was found in the supernate of th...

It is widely accepted that the neoplastic B cells from patients with chronic lymphocytic leukemia (CLL) respond poorly to common mitogens. The fungal metabolite cytochalasin B (0.5 micrograms/ml) is a weak mitogen for normal lymphocytes. However, when peripheral blood lymphocytes from 19 patients with CLL of B cell origin (B-CLL) were cultured with 0.5 micrograms cytochalasin B/ml, significant ...

An effective and inexpensive protocol for producing cytochalasins A and B is being disclosed to propose a viable method by which to examine the in vivo antineoplastic activity of these congeners in preclinical tumor-bearing mammalian models. In addition, we determine the maximum tolerated doses of cytochalasin B using multiple routes and formulations, characterize the tissue distribution of int...

Endophytic fungi are fungi that colonize internal tissues of plants; several biologically active compounds have been isolated from these fungi. There are few studies of compounds isolated from endophytic fungi of Amazon plants. Thus, this study aimed the isolation and structural identification of ergosterol (1), ergosterol peroxide (2), mevalonolactone (3), cytochalasin B (4) and cytochalasin H...

Functional and morphologic effects of cytochalasin B on the cultivated macrophage were examined to determine the basis for plasma membrane movements of the type required for endocytosis and/or spreading on a substratum. Inhibition of phagocytosis and changes in cell shape by cytochalasin B exhibited nearly identical dose-response curves requiring 2-5 x 10(-6) M and 1-2 x 10(-5) M cytochalasin B...

Low concentrations (greater than or equal to 10(-7) M) of cytochalasin B reversibly inhibit the temperature-dependent gelation of actin by an actin-binding protein. The cytochalasin B concentrations which maximally inhibit actin gel formation are 10-fold lower than the concentrations which maximally impair phagocytosis by intact macrophages. Cytochalasin B also prevents the polymerization of mo...

Background: The parthenogenetic of oocytes is important in cloning research, as artificial activation of oocytes is an essential component of nucleus transfer protocols. Hydrostatic pressure can act as a mechanical stimulator that rearranges egg contents. Ethanol promotes a single intracellular Ca2+ increase of greater and longer amplitude than the initial increase observed at fertilization. In...

Survivin and securin proteins are overexpressed in most cancer cells that have been shown to regulate mitotic progression. In this study, we investigated the roles of survivin and securin on cytochalasin B, a cytokinesis blocker mediating the cytotoxicity and cell growth inhibition in human cancer cells. The human lung carcinoma cell lines A549 and H1299 highly expressed survivin proteins in mi...

Tritium-labeled cytochalasin B of high specific activity (6 Ci per mmole) has been prepared by reduction of cytochalasin A with [3H]NaBH4. The structure of the radioactive product was shown to be identical with that of authentic cytochalasin B by high resolution mass spectrometry, chromatographic analysis, and derivatization. The synthesized compound produced the same effects as authentic cytoc...