Type III secretion system

Although plant and animal pathogens infect different hosts, there are several similarities in the strategies employed (Buckhout and Thimm, 2003). For example, Type III secretion systems can be found in both plant and animal pathogens. The Type III secretion system is... 

It is thought that cell surface components such as cellulose, flagella, pilli, and Type III secretion systems all play a role in cell attachment (Barak et al., 2005 Zogaj et al., 2001). Several genes and mechanisms have been identified as being involved in attachment of human pathogens to plants. These mechanisms include curli, fimbriae, adhesins, and capsule production (Barak et al., 2005, 2007). 

Zarivach, Raz, Marija Vuckovic, Wanyin Deng, B. Brett Finlay, and Natalie C. Strynadka. Structural Analysis of a Prototypical ATPase from the Type III Secretion System. Nature Structural and Molecular Biology 14 (2007) 131-137. The researchers used X-ray crystallography and other techniques to describe the structure of a critical enzyme. 

Cirillo, D., Valdivia, R., Monack, D., Falkow, S. Macrophage-dependent induction of the Salmonella pathogenicity island 2 type III secretion system and its role in intracellular survival. Mol Microbiol 30 (1998) 175-188. 

Hensel, M., Shea, J., Waterman, S., Mundy, R., Nikolaus, T., Banks, G., Vazquez-Torres, A., Gleeson, C., Fang, F., Holden, D. Genes encoding putative effector proteins of the type III secretion system of Salmonella pathogenicity island 2 are required for bacterial virulence and proliferation in macrophages. Mol Microbiol 30 (1998) 163-174. 

Alfano, J.R., Collmer, A. Type III secretion system effector proteins Double agents in bacterial disease and plant defense. Annu Rev Phytopathol 42 (2004) 385-414. 

But as I pointed out above, there s no reason that parts or subassemblies of irreducibly complex systems can t have one or more other functions, and wordplay can t masquerade as a real explanation. Neither the TTSS, the flagellum, nor any transitions between them have been soberly investigated in a Darwinian framework in the professional science literature. The best place to see this is in a recent paper entitled, Bioinformatics, genomics, and evolution of non-flagellar type-III secretion systems a Darwinian perspective.))27 In it we learn that A type-III secretion system is an exquisitely engineered [emphasis added] molecular pump,... 

Recent work indicates that a major virulence mechanism for Salmonella may involve type III secretion systems, which are encoded on plasmids and allows direct transfer of bacterial proteins to eukaryotic cells through a contact-dependent secretion mechanism. These effector proteins are capable of enhancing virulence and epithelial cell invasion. 

In common with the other pathogenic yersiniae, virulence of Y. pseudotuberculosis is dependent on the presence of a 70-kb virulence plasmid pYV (plasmid associated with Yersinia virulence). Encoded in pYV is a type III secretion system which is necessary for survival and replicates within lymphoid tissues of animal or human hosts [25], Also encoded in the pYV plasmid are a set of pathogenicity factors, including those known as Yersinia outer proteins. Yersinia outer proteins are exported by the type III secretion system upon bacterial infection of host cells, and function to disrupt innate and adaptive immune responses to infection [26],... 

Another example of a bacterial pathogen using phosphoinositide metabolism to enter host cells is the Gram-negative bacillus Shigella flexnerl Shigella injects, by its type III secretion system, a protein, IpgD, which has two... 

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