Common architectures in cyanobacteria Prochlorococcus cells visualized by X-ray diffraction imaging using X-ray free...

Area of Science:

• Cell Biology
• Microbiology
• Biophysics

Background:

• Understanding intracellular structures and their spatial organization is crucial for deciphering cellular functions.
• Cyanobacteria, like Prochlorococcus, are vital microorganisms whose internal organization remains incompletely understood.
• Non-invasive imaging techniques are needed to study delicate cellular structures without modification.

Purpose of the Study:

• To investigate the intracellular structure and spatial organization of cyanobacteria Prochlorococcus in the interphase.
• To develop and apply X-ray diffraction imaging for high-resolution visualization of microbial cells.
• To correlate observed intracellular structures with known cellular components and biological functions.

Main Methods:

• Utilized X-ray diffraction imaging with an X-ray free-electron laser (XFEL).
• Collected high signal-to-noise diffraction patterns from single, unmodified cyanobacteria cells (<1 µm).
• Reconstructed electron density maps and a 3D map using diffraction data and reference fluorescent images.

Main Results:

• Achieved 30 nm resolution imaging of intracellular structures.
• Identified a consistent C-shaped arrangement of 100-nm high-density spots surrounding a 100-nm low-density area in Prochlorococcus cells.
• Reconstructed a non-uniform 3D map revealing common intracellular structures and inferred the spatial arrangement of thylakoid membranes, nucleoids, and carboxysomes.

Conclusions:

• X-ray diffraction imaging with XFEL provides high-resolution, non-invasive visualization of microbial intracellular organization.
• A conserved C-shaped structure and specific spatial arrangements of key organelles exist in interphase Prochlorococcus.
• The study provides insights into the relationship between intracellular organization and biological functions in cyanobacteria.