4.d Figure 1e: Fill out the following table (where highlighted) The first row is

ID: 225659 • Letter: 4

Question

4.d Figure 1e: Fill out the following table (where highlighted) The first row is an example Variable Observation Explanation (one sentence) (-5 pt each) These mice were not exposed to The thi remained Wt mice mock infected Salmonella, and produced no thiosulfate because no oxidative detectable tetrathionate burst oxidized it to tetrathionate why? Wild type mice Salmonella Exposed to wild type infection Salmonella, but no tetrathionate detected. Wild type mice invA/spiB No tetrathionate detected Why? (Salmonella that can't attach to gut lining) why? Wild type mice ttr (Salmonella Tetrathionate detected that cannot reduce tetrathionate)

Explanation / Answer

Wt mice + mock infected

These mice were not exposed to Salmonella and produced no detectable tetrathionate

The thiosulfate remained thiosulfate because no oxidative burst oxidized it to tetrathionate.

Wild type mice + Salmonella infection

Exposed to wild type Salmonella, but no tetrathionate detected

The ttr genes in the Salmonella might promote consumption of this electron acceptor (tetrathionate) during infection and thus they are not detected.

Wild type mice + invA/spiB (Salmonella that can’t attach to gut lining)

No tetrathionate detected

The mutant Salmonella (invA/spiB) can’t promote inflammation of the gut which is necessary for the generation of tetrathionate.

Wild type mice + ttr (Salmonella that can’t reduce tetrathionate)

Tetrathionate detected

The mutant Salmonella (ttr) are unable to reduce the tetrathionate and thus they are easily detected as remnants.