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Cell wall growth during differentiation of Proteus swarmers
Abstract:
This paper describes the process by which the cell wall of Proteus mirabilis, as measured by the presence of the O antigen, develops during the differentiation of swarmers from short cells on an agar surface. The sequence was followed by fluorescent-antibody staining, with both the direct and reverse methods. When the organisms were labeled with fluorescent antibody by the direct method, they showed a progressive diminution of the marker along the cell surface and some increase in the length of the bacteria. However, the label had become completely diluted out before typical swarmers developed. When the bacteria were exposed initially to unlabeled antibody by the reverse technique, and then incubated with fluorescent antibody, they showed a progressive increase both in the intensity of the label along their entire periphery and in cellular length, culminating in the formation of swarmers. It is concluded that in P. mirabilis, as in the few other gram-negative bacteria examined so far, cell wall synthesis takes place diffusely, i.e., by intercalation of new with old components along the length of the cell wall.
Insights
Proteus mirabilis cell wall growth occurs diffusely, with new components integrating along the entire cell length. This process, observed via fluorescent-antibody staining, explains swarmer cell differentiation from short cells.
Area of Science:
- Microbiology
- Cell Biology
- Bacterial Physiology
Background:
- Proteus mirabilis exhibits complex differentiation into swarmer cells.
- Understanding bacterial cell wall synthesis is crucial for comprehending growth and division.
Purpose of the Study:
- To investigate the mechanism of cell wall development during swarmer cell differentiation in Proteus mirabilis.
- To determine the pattern of cell wall synthesis in P. mirabilis.
Main Methods:
- Utilized fluorescent-antibody staining techniques (direct and reverse methods).
- Monitored the O antigen as a marker for cell wall synthesis.
- Observed changes in cell length and antibody labeling intensity during differentiation.
Main Results:
- Direct fluorescent-antibody staining showed marker dilution and cell elongation.
- Reverse staining revealed progressive increase in label intensity and cell length, leading to swarmer formation.
- Cell wall synthesis was not localized but occurred diffusely.
Conclusions:
- Cell wall synthesis in Proteus mirabilis occurs diffusely, involving intercalation of new components along the cell wall.
- This diffuse synthesis pattern is consistent with other gram-negative bacteria studied.
- The findings provide insight into the morphological changes during swarmer cell differentiation.