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Fig. 8 | Microbiome

Fig. 8

From: The tick endosymbiont Candidatus Midichloria mitochondrii and selenoproteins are essential for the growth of Rickettsia parkeri in the Gulf Coast tick vector

Fig. 8

Proposed model for Rickettsia–symbiont interactions and the functional significance of selenoproteins in rickettsial replication inside tick tissues. The colonization of R. parkeri in A. maculatum gives it an opportunity to dynamically interact with tick symbionts and modulate tick defenses by regulating tick gene expression (e.g., selenogenes). In R. parkeri-free (Rp) tick cells, FLE and CMM are present and normal expression levels of tick selenoproteins (SELENOM, SELENOO, and SELENOS) occur. In R. parkeri-infected (Rp+) tick cells, the normal symbiont dynamics are altered such that CMM replicates and FLE numbers decline, and the selenoprotein expression levels are upregulated. Knocking down the selenoproteins by RNA interference reduces the selenoprotein expression levels, and the elevated levels of reactive oxygen species impair the replication of both R. parkeri and CMM while FLE replicates at normal levels. SELENOM (SELM)-SELENO (SELO)-SELENOS (SELS)

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