Cellular Microbiology

Dictyostelium discoideum Sey1 is the single ortholog of mammalian atlastin 1-3, which are large homodimeric GTPases mediating fusion of tubular endoplasmic reticulum (ER). Mutant amoebae lacking Sey1 grow and develop similarly to the parental strain, but show an aberrant ER architecture, defects in proteolytic processes and diminished cell motility. In ∆sey1 amoebae, the recruitment of ER to the unique vacuole harboring the pathogen Legionella pneumophila is reduced, expansion of the ER-associated vacuole is defective, and intracellular bacterial growth is impaired.

Conidiophore of A. fumigatus carrying asexual spores that are coated with GFP as expressed from the defensin-like peptide-encoding defX gene. For further details, readers are referred to the article by Dümig et al. on p. e13301 of this issue.

Inhibition of protease activity prevented degradation of proteins and also blocked cell proliferation, suggesting that a novel protease complex contributes to bacterial virulence.

Confocal immunofluorescence image of gut tissues in a partially-fed Ixodes scapularis nymphal tick. An acellular membrane called peritrophic membrane (green) separates the gut epithelial cells (red) from underlying luminal areas (black). For further details, readers are referred to the article by Yang et al. on p. e13275 of this issue.