Chlamydia psittaci infected cell studies by 4Pi Raman and atomic force microscopy

Area of Science:

• Microbiology
• Cell Biology
• Biophysics

Background:

• Chlamydia psittaci is an avian pathogen causing zoonotic atypical pneumonia in humans.
• As an intracellular bacterium, C. psittaci resides within host cell inclusions, complicating direct study.
• Non-destructive analysis methods are crucial for understanding host-pathogen interactions.

Purpose of the Study:

• To develop and demonstrate a combined microscopy approach for analyzing intracellular bacteria within intact host cells.
• To investigate the morphological and molecular characteristics of host cells infected with C. psittaci.
• To characterize the intracellular inclusion formed by C. psittaci.

Main Methods:

• Utilized Atomic Force Microscopy (AFM) for high-resolution surface imaging of infected cells.
• Employed 4Pi Raman microscopy for molecular probing of intracellular bacteria and inclusions.
• Combined AFM and 4Pi Raman microscopy for a correlative multitool analysis.

Main Results:

• AFM revealed morphological changes in infected cell membranes, including increased roughness and microvesicle formation.
• 4Pi Raman microscopy provided molecular insights into intracellular C. psittaci and its inclusion.
• The inclusion showed a molecular fingerprint similar to lipid droplets but with reduced protein and unsaturated lipid content.

Conclusions:

• The combined multitool microscopy approach offers a powerful, non-destructive method for studying intracellular bacteria.
• This technique provides complementary information on both cellular morphology and molecular composition.
• The findings aid in understanding C. psittaci pathogenesis and host cell responses.