ADP-ribosyltransferase activity of Legionella pneumophila is stimulated by the presence of macrophage lysates.

ADP-ribosyltransferases are among the most biologically active of bacterial products in eukaryotes, and act by transferring the ADP-ribosyl moiety of NAD to acceptor proteins. The detection of ADP-ribosylated Legionella proteins in ultrasonic lysates of Legionella pneumophila strain Philadelphia 1 is reported. The ADP-ribosylating reaction was not influenced by addition of guinea pig spleen-cell and lung-cell lysates, but was considerably increased in the presence of lysates of guinea pig peritoneal macrophages, which are known to be target cells for virulent Legionella.

Signal transduction in eukaryotic cells and intracellular parasitism of Legionella.

A fundamental property of the eukaryotic cell is its ability to respond to external signals. This property becomes extremely important during microbial invasion, when the volume of information to be analyzed by the cellular receptor machinery increases considerably. Cell-surface receptors are influenced by a pool of additional ligands, some of the most important of these being the infecting microorganism, products of bacterial metabolism, virulence factors, as well as regulators produced by the endocrine and immune systems of the infected animal (e.

Partial purification and characterization of ADP-ribosyltransferase produced by Legionella pneumophila.

A scheme for the partial purification of a Legionella pneumophila product possessing ADP-ribosyl-transferase and NAD-glycohydrolase activities is presented. The purification steps consisted of gel chromatography, ion-exchange, hydrophobic interaction chromatography, and chromatofocusing. The partially purified preparation modified eukaryotic components of molecular mass 20-25 kDa, which it is proposed are GTP-binding proteins.

Purification and some properties of exotoxin from Corynebacterium ulcerans strain ATCC 9015.

Corynebacterium ulcerans strain ATCC 9015 develops during growth in environmental media an exotoxin which is lethal for guinea-pigs. The exotoxin has been purified by ion-exchange chromatography on DEAE-Sephadex A-50, affinity chromatography using immunosorbent techniques, and gel-filtration through Sephadex G-75. The exotoxin is of a protein nature and consists perhaps of two subunits.

Proof for the lack of diphtheria toxin in culture filtrates of Corynebacterium ulcerans strain ATCC 9015.

Extensive efforts to identify the diphtheria toxin in culture filtrates of C. ulcerans strain ATCC 9015 was unsuccessful. The culture filtrates did contain a component (called D-antigen) which formed a precipitin line with commercial diphtheria antitoxin.