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Ever since it was blamed for massive fish kills in estuaries in the eastern United States a decade ago, a tiny one-celled organism known as Pfiesteria piscicida has fascinated and [...]

The environmental expression of sulfur compound disproportionation has been placed between 640 and 1050 million years ago (Ma) and linked to increases in atmospheric oxygen. These arguments have their basis in temporal changes in the magnitude of [sup.34]S/[sp.32]S fractionations between sulfate and sulfide. Here, we present a Proterozoic seawater sulfate isotope record that includes the less abundant sulfur isotope 33S. These measurements imply that sulfur compound disproportionation was an active part of the sulfur cycle by 1300 F4a and that progressive Earth surface oxygenation may have characterized the Mesoproterozoic., There is a strong link between the oxidation state of the Earth's surface environment and the microbial sulfur metabolisms that influence the sulfur cycle (1-3). This link is revealed through [...]

A number of bacterial protein toxins, including adenylate cyclase (AC) toxin from Bordetella pertussis, require the product of an accessory gene in order to express their biological activities. In this study, mass spectrometry was used to demonstrate that activated, wild-type AC toxin was modified by amide-linked palmitoylation on the E-amino group of lysine 983. This modification was absent from a mutant in which the accessory gene had been disrupted. A synthetic palmitoylated peptide corresponding to the tryptic fragment (glutamine 972 to arginine 984) that contained the acylation blocked AC toxin-induced accumulation of adenosine 3',5'-monophosphate, whereas the nonacylated peptide had no effect., Adenylate cyclase toxin is a virulence factor from Bordetella pertussis, the bacterium that causes pertussis or 'whooping cough.' This disease is responsible for an estimated 340,000 deaths per year, largely [...]

Enhancement of Symbiotic Dinitrogen Fixation by a Toxin-Releasing Plant Pathogen WE HAVE OBSERVED AN UNUSUAL and highly beneficial infestation of nodulating alfalfa plants by a toxin-releasing Pseudomonas (Fig. 1). Infestation [...]

Three-Dimensional Structure of Cholera Toxin Penetrating a Lipid Membrane MANY POLYPEPTIDE TOXINS AND GLYCOPROTEIN HORmones are composed of two types of chain, one (B) which binds a cell surface receptor, [...]

Pertussis Toxin Gene: Nucleotide Sequence and Genetic Organization PERTUSSIS TOXIN (1) IS ONE OF THE various toxic components produced by virulent Bordetella pertussis, the microorganism that causes whooping cough. A [...]