Related Experiment Video
Updated: Jun 7, 2026

Isolation of Salmonella typhimurium-containing Phagosomes from Macrophages
Published on: October 25, 2017
Membrane tubules attach Salmonella Typhimurium to eukaryotic cells and bacteria
Svetlana I Galkina1, Julia M Romanova, Elizaveta E Bragina
1A.N. Belozersky Institute of the Moscow State University, Moscow, Russia. galkina@genebee.msu.su
Abstract:
Using scanning electron microscopy techniques we measured the diameter of adhesive tubular appendages of Salmonella enterica serovar S. Typhimurium. The appendages interconnected bacteria in biofilms grown on gallstones or coverslips, or attached bacteria to host cells (human neutrophils). The tubular appendage diameter of bacteria of virulent flagellated C53 strain varied between 60 and 70 nm, thus considerably exceeding in size of flagella or pili. Nonflagellated bacteria of mutant SJW 880 strain in biofilms grown on gallstones or coverslips were also interconnected by 60-90-nm tubular appendages. Transmission electron microscopy studies of thin sections of S. Typhimurium biofilms grown on agar or coverslips revealed numerous fragments of membrane tubular and vesicular structures between bacteria of both flagellated and nonflagellated strains. The membrane structures had the same diameter as tubular appendages observed by scanning electron microscopy, indicating that tubular appendages might represent membrane tubules (tethers). Previously, we have shown that neutrophils can contact cells and bacteria over distance via membrane tubulovesicular extensions (TVE) (cytonemes). The present electron microscopy study revealed the similarities in size and behavior of bacterial tubular appendages and neutrophil TVE. Our data support the hypothesis that bacteria establish long-range adhesive interactions via membrane tubules.
Related Concept Videos
Cytoskeletal Proteins in Bacteria
Bacterial Translocation and Protein Secretion
Microtubules
Microtubules
Microtubules have two structurally similar globular protein subunits: α and β tubulins. In the cytosol, the α and β tubulins form a heterodimer. These αβ-heterodimers...
Flagella and Motility in Bacteria
Fimbriae, Pili, and Axial Filaments

