Wolf Lichter

Crystallization and toxicology of T34: A major toxin from Florida's red tide organism (Ptychodiscus brevis)

Abstract The purification and crystallization of a major toxin from laboratory cultures of Floridas fed tide organism, Ptychodiscus brevis , is described. The crystalline toxin is soluble in acetone and chloroform, less soluble in ethyl acetate, methanol and ethanol, and is slightly soluble in water. The crystalline toxin is stable when stored in a moisture-free environment. The toxin is lethal to fish and mice, inhibits growth in three in vitro cell culture systems, and inhibits the division of fertilized sea urchin eggs. It has no effect on the formation of antibodies directed against sheep red blood cells in mice, and does not inhibit the morphological transformation of rat glioma cells from a fibroblast-like to a glial-like cell.

Two cytotoxic pentacyclic triterpenoids from Nerium oleander

The isolation and structure elucidation of two novel cytotoxic pentacyclic triterpenoids cis-karenin (3β-hydroxy-28-Z-p-coumaroyloxy-urs-12-en-27-oic acid) and trans-karenin (3-β-hydroxy-28-E-p-coumaroyloxy-urs-12-en-27-oic acid) from the leaves of Nerium oleander is described.

Ecteinascidia turbinata extracts inhibit DNA synthesis in lymphocytes after mitogenic stimulation by lectins.

Summary Aqueous ethanol extract of a tunicate which was previously found to exert antitumor and immunosuppressive activities in vivo was tested for its effect on normal human lymphocytes in vitro. The extract suppressed the uptake of tritiated thymidine by lymphocytes stimulated with mitogen. This suppressive effect did not require continuous presence of the extract. Treatment of lymphocytes prior to mitogenic stimulation resulted in suppressive effect. The fact that suppression by the extract could also be achieved 24 hr after exposure to mitogen, an interval which was found to suffice for the attainment of maximal commitment for blastogenic transformation indicates that Ete can act at a stage subsequent to the binding of the lectin and elicitation of a mitogenic signal(s).

Studies on latent infections of tissue cultures with dengue virus. I. Characteristics of the system.

Upon primary infection of KB cells, dengue virus proliferated without concomitant cell destruction. Such cultures exhibited an increased resistance to poliovirus and became persistently infected with dengue. The chronically infected cultures were characterized by enhanced interference with polio virus, inability to be cured by prolonged treatment with dengue immune serum, continued lack of cytopathogenic changes, decreasedin vitro growth rates and decreased capacity to produce tumors upon transplantation to the brains of rats. The amount of infectious virus as demonstrated by inoculation of suckling mice was relatively low, usually on the order of less than one infectious unit per cell.

Immunomodulation by Corynebacterium Parvum

Corynebacteriumparvum which has recently been reclassified as a Propionibacterium (1) was initially noted for its ability to stimulate the reticuloendothelial system (RES) as manifested by increased clearance of particulate material from the circulation and increased spleen and liver weights (2–5). Since then, the ability of this organism to modify various immune functions has been extensively studied.

Substances from Marine Organisms Influencing Tumor Growth and Immune Responses

The sea which is a readily accessible receptacle for man-made wastes and pollution of coastal water has become the concern of environmentalists and public health authorities alike. What has escaped their attention is that, in addition to exogenous pollution, the sea can receive conglomerates of substances produced by its inhabitants which can affect its biosphere in a favorable or deleterious way.