Submitted to: Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 11, 1997
Publication Date: N/A
Interpretive Summary: Little is known about the life of bacteria in their natural environment. This manuscript describes conditions that provide Salmonella enteritica essential environmental signals it requires to display its full range of biological behavior. Such approaches already exist for cell biologists who investigate the complex processes of eukaryote differentiation and development. The information presented in this manuscript is immediately applicable to the improvement of vaccines and the production of proteins used in human medicine from genetically engineered bacteria. In addition, this research has long-term implications for understanding the basic mechanisms by which enteric bacteria colonize farm animals, survive in foods, and cause illness in people. Specific findings are as follows: 1) direct demonstration that Salmonella pullorum, a chicken-adapted pathogen, produces flagella as do other salmonellae, 2) the structural protein flagellin has different isotypes and different functions for each isotype and 3) all Salmonella use the concentration of many simple metabolites as environmental signals that are required to induce cellular differentiation and development of new biological functions.
Technical Abstract: Concentrations of sugars and amino acids at 100 mM reliably induced cellular differentiation of Salmonella enterica on selective agar and in broth. Enhancement required iron and sodium thiosulfate. Induced Salmonella produced flagellin electrophoretic isotypes of 60, 54 and 50 kDa, and two of these were associated with smooth lipopolysaccharide. Even historically aflagellate S. enterica var. Pullorum produced two of three flagellin isotypes. A rough strain of var. Enteritidis became smooth at 100 mM glucose, whereas smooth virulent var. Enteritidis hyperflagellated. Var. Typhimurium LT2 hyperflagellated in broth at both 10 and 100 mM glucose. The conditions appear to alleviate oxidative stress and improve survival of differentiating cells.