Salmonella temperature dependent proteome

Salmonella enterica serovar Typhimurium (STM) is one of the major causes of gastroenteritis and is linked to the consumption of contaminated food. Thereby, STM is associated to food of animal related produce (pork, chicken, eggs) and to food of non-animal related produce (vegetables, fruits, nuts, herbs and water). A lot of studies investigated the process of infection of warm-blooded mammalian hosts by STM and the underlying complex regulatory network of virulence gene expression dependent of various environmental conditions encountered in hosts. However, less is known about the proteome and possible regulatory networks for gene expression of STM outside the preferred host. Nutritional limitations and changes in temperature are the most obvious stresses outside the native host. Thus, we analyzed the proteome profile of STM grown in rich medium (LB medium) and minimal medium (PCN medium) at temperatures ranging from 8 °C to 37 °C. LB medium mimics the nutritional rich environment inside the host, whereas minimal PCN medium represents nutritional limitations outside the host, found during growth of non-animal related produce (field conditions). Further, the used range of temperature is found inside natural hosts (37 °C), at ambient room conditions (20 °C), during agricultural growth on open field (16 °C and 12 °C) and probably during food storage (8 °C). For the investigation of implications of altered nutrient availability and changes in growth temperature on STM proteome, whole cell lysates of STM grown under various conditions were analyzed by HPLC/MS-MS and label-free quantification. With this method, we are able to decipher changes in the complete proteome of STM in comparison to standard laboratory conditions mimicking the natural host.