Wolbachia Infect Ovaries in the Course of Their Maturation: Last Minute Passengers and Priority Travellers?
Figure 7
Average intensity projections of ovaries: Wolbachia (red and grayscale) detection in infected ovaries at different maturation stages: Immature (A), Mature I (B 1 and 2), Mature II (C), versus control uninfected ovary (D).
The germaria are at the bottom, the scale bars placed in front of the oviduct insertion. A: Oocytes are only present along the thin band of the germarium (30.5% infected; infected oocytes: e.g. red arrowheads; uninfected ones: e.g. green arrowheads). B: Wolbachia are present as a mass near the nucleus of oocytes of all sizes (e.g. red arrowheads) and their follicle cells (infection there appears as a network surrounding the oocytes, e.g. red arrows), though many oocytes remained uncolonized (e.g. green arrowheads), especially the smaller ones. In the B1 ovary the colonized oocytes are roughly arranged as triangles, one tip stemming from the germarium side and expanding to the mature side (51% of infection), while the pattern in B2 (67% of infection) is more representative of this category, in so far as the colonization is not so linear. Also some colonized oocytes are not surrounded by infected follicle cells (e.g. red circles) and vice versa (e.g. red squares). C: Mature II is the most advanced stage in maturation (infected oocyte: e.g. red arrowhead; uninfected oocyte: e.g. green arrowhead). In addition to the Wolbachia signal the inside of the oocytes is filled with autofluorescing material, probably vitellogenin. D: Uninfected ovary. Red and grayscale: Wolbachia FISH probe W1,2-Cy3, green: phalloidin, blue: DAPI.