Chapter 12, Problem 3CHI

Magnetotactic bacteria are morphologically and metabolically complex microbes that produce intracellular, membrane-bound magnetic crystals (see figure 3.37). The magnetotactic bacterial isolates called MV-1 and MC-1 both grow chemolithoautotrophically. However, MV-1 uses the Calvin-Benson cycle to fix carbon, whereas MC-1 uses the reductive TCA cycle.

Refer to figures 12.4 and 12.5 to identify key enzymatic steps in each pathway. How do you think the microbiologists studying these fascinating microbes were able to conclude that these two bacterial isolates use two different pathways for carbon fixation?

Read the original paper: Williams, T. J., et al. 2006. Evidence for autotrophy via the reverse tricarboxylic acid cycle in the marine magnetotactic coccus strain MC-1. Appl. Environ. Microbiol. 72:1322.