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Updated: Oct 2, 2026
Live-Cell Fluorescence Microscopy to Investigate Subcellular Protein Localization and Cell Morphology Changes in Bacteria
Published on: November 23, 2019
Changes in the cell structure of Flavobacterium psychrophilum with length of culture
Abstract:
Flavobacterium psychrophilum, the pathogen of bacterial cold-water disease, causes serious problems in ayu Plecoglossus altivelis culture. This study investigated the effect of the culture period of F. psychrophilum and on the structure of its cells. From the SDS-PAGE of total proteins of cellular components, much difference was found between the 36 hr culture and the 48 and 72 hr cultures. A SEM observation of the cells showed many fragments, especially on the cell surface of the 36 hr culture. These fragments consisted of an outer membrane, seen by TEM observation, and may contain substances causing the virulence. Specific proteins observed by the SDS-PAGE and fragments in the 36 hr culture may be related to the virulence of F. psychrophilum.
Insights
Flavobacterium psychrophilum virulence is linked to cell structure changes over time. Early cultures (36 hr) show outer membrane fragments potentially containing virulence factors, differing from later cultures.
Area of Science:
- Aquatic microbiology
- Fish pathology
- Bacterial cell biology
Background:
- Flavobacterium psychrophilum causes significant economic losses in ayu aquaculture due to bacterial cold-water disease.
- Understanding the pathogen's lifecycle and virulence factors is crucial for disease management.
Purpose of the Study:
- To investigate how the culture period affects the cellular structure of Flavobacterium psychrophilum.
- To identify potential virulence-associated components in F. psychrophilum.
Main Methods:
- Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) to analyze total proteins.
- Scanning electron microscopy (SEM) to observe cell surface morphology.
- Transmission electron microscopy (TEM) to examine cell structures, specifically outer membranes.
Main Results:
- Significant differences in protein profiles were observed between 36-hour cultures and later cultures (48 and 72 hours) via SDS-PAGE.
- SEM revealed abundant cell surface fragments in 36-hour cultures.
- TEM confirmed these fragments were composed of outer membrane material, suggesting a role in virulence.
Conclusions:
- The early culture stage (36 hr) of F. psychrophilum is characterized by distinct cellular structures and protein expression.
- Outer membrane fragments observed in early cultures may harbor virulence-associated substances.
- These findings suggest a correlation between specific proteins and cell surface fragments in early cultures and the virulence of F. psychrophilum.
