Researchers from the University of California at Berkeley have identified a gene that may allow salmonella bacteria to contaminate chicken eggs. Their findings appear in the December 2003 issue of the journal Infection and Immunity.
Salmonella enterica serovar Enteritidis in eggs is one of the leading causes of food-borne illnesses in the United States. S. enterica is the only strain able to invade eggs and survive despite the antibacterial defenses found in egg whites which limit the growth and survival of other bacteria.
In the study, S. enterica was combined with albumen from egg whites and then monitored for survival. After confirming that S. enterica was able to overcome exposure to the albumen, the researchers began identifying genes that might contribute to the resistance. One of the genes, identified as yafD, had the ability to repair DNA damage caused by the albumen enabling the bacterium to thrive.
"We report here the identification of yafD as a gene essential for the resistance of S. enterica serovar Enteritidis to egg albumen," say the researchers. "We provide evidence that YafD may play a role in the repair of DNA damage caused by egg albumen and hence may facilitate the survival of S. enterica serovar Enteritidis in chicken eggs."
(S. Lu, P.B. Killoran, L.W. Riley. 2003. Association of Salmonella enterica serovar enteritidis YafD with resistance to chicken egg albumen. Infection and Immunity, 71. 12: 6734-6741.)
DIFFERENT BACTERIA CAUSE DISEASE IN GRAPES/ALMONDS
Scientists at the University of California, Berkeley, have discovered that while Pierce's disease of grapevines (PD) and almond leaf scorch (ALS) are caused by the same species of bacteria, the bacteria are two distinctly different strains. They report their findings in the December 2003 issue of the journal Applied and Environmental Microbiology.
Contact: Jim Sliwa
American Society for Microbiology