How many Salmonella pathogenicity islands are there?

Salmonella typhimurium possesses at least five such pathogenicity islands (SPI), which confer specific virulence traits and may have been acquired by horizontal transfer from other organisms. We highlight recent progress in characterizing these SPIs and the function of some of their genes.

Is Salmonella a protein?

As a result, the number of known small Salmonella proteins has grown by 139 to over 600. The small protein MgrB, which consists of 47 amino acids, stood out in the analyses. If the gene containing the blueprint for this protein is switched off, the salmonellae can no longer infect human cells.

What is the function of Spi-1 encoded T3SS?

The SPI-1-encoded T3SS is required not only for cell invasion but also for suppression of early proinflammatory cytokine expression in macrophages, including that of IL-1β, IL-8, TNF-α, IL-23α, GM-CSF, and IL-18 ( Pavlova et al., 2011 ).

What is the role of Spi-1 in host immunology?

This review focuses on the effect and the regulation of SPI-1 and the relationship between host immunology and SPI-1 in Salmonella. Salmonella pathogenicity island 1 (SPI-1) plays a crucial role in the interaction between Salmonella and host cells.

How does Salmonella pathogenicity island 1 ( SPI-1 ) work?

Salmonella pathogenicity island 1 (SPI-1) plays a crucial role in the interaction between Salmonella and host cells. SPI-1 promotes Salmonella invasion into epithelial cells (Raffatellu et al., 2005). The T3SS is assembled from the proteins encoded by SPI-1 and is termed the needle complex.

How many genes are in the SPI-1 gene cluster?

SPI-1 is a gene cluster and consists of a 40-kb region, which includes 39 genes encoding T3SS-1 and its chaperones and effector proteins as well as some transcriptional regulators that control the expression of many virulence genes located within and outside SPI-1 ( Hansen-Wester and Hensel, 2001; Zhang K. et al., 2018 ).