1. Addition of antidiuretic hormone (ADH) to the bladders of toads (Bufo marinus) preloaded with (45)Ca causes an increase in the rate of calcium efflux.2. Pretreatment of the serosal surfaces of bladders with phospholipase C prevents the action of ADH on calcium efflux.

A new salicylic acid derivative, caloporoside, was isolated from fermentations of Caloporus dichrous. Its structure was elucidated by a combination of chemical and spectroscopic methods. Caloporoside exhibits weak antibacterial and antifungal activities and is a quite selective inhibitor of phospholipase C isolated from pig brain (Ki 12, 3 microM).

Clostridium perfringens was incubated in the presence of euflavine (EU); the resistant mutants which were thus isolated had highly reduced capacity to release alpha-toxin. This fact was confirmed by lecithinase determinations and by immunoelectrophoresis. Injected into guinea pigs and into 6- to 7-day-old chicks, these mutants were completely avirulent. A study of their properties indicated bio...

Blocking the activity of IL-1 beta has entered the clinical arena of treating autoimmune diseases. However, a successful outcome of this approach requires a clear definition of the mechanisms controlling IL-1 beta release. These are still unclear as IL-1 beta, lacking a secretory signal peptide, follows a nonclassical pathway of secretion. Here, we analyze the molecular mechanism(s) undergoing ...

A phospholipid mixture was isolated from bovine vesicle tissue. This phospholipid preparation contained the following prostaglandin precursor fatty acids: 4.7 percent 5,8,11-eicosatrienoic acid, 9.1 percent 5,8,11,14-eicosatetraenoic acid and 0.9% 5,8,11,14,17-eicosapentaenoic acid. With this phospholipid preparation as substrate phospholipase activity could be detected in different fractions o...

Calcium has been implicated as a regulatory factor in many physiological and pathophysiological processes in the renal cell. Under physiological conditions, the cytosolic free calcium concentration is maintained at approximately 100 nM. Most of the releasable cell Ca2+ resides in the nonmitochondrial compartments. In addition to the plasma membrane Ca2+ transport processes, there is a high-affi...

It has recently been reported (T. Shimizu et al., J. Biol. Chem., 273: 8669-8674, 1998) that the pro-apoptotic drug, camptothecin, an inhibitor of topoisomerase I, induces a protein kinase C-alpha-mediated phosphorylation of lamin B in HL-60 cells, which precedes both degradation of lamin B and fragmentation of DNA. In this paper, we report that, in HL-60 cells exposed to camptothecin, there is...

It has recently been reported (T. Shimizu et al., J. Biol. Chem., 273: 8669–8674, 1998) that the pro-apoptotic drug, camptothecin, an inhibitor of topoisomerase I, induces a protein kinase C-a-mediated phosphorylation of lamin B in HL-60 cells, which precedes both degradation of lamin B and fragmentation of DNA. In this paper, we report that, in HL-60 cells exposed to camptothecin, there is a r...

Microbial pathogens use a number of genetic strategies to invade the host and cause infection. These common themes are found throughout microbial systems. Secretion of enzymes, such as phospholipase, has been proposed as one of these themes that are used by bacteria, parasites, and pathogenic fungi. The role of extracellular phospholipase as a potential virulence factor in pathogenic fungi, inc...