Treponeme outer envelope: chemical analysis.

Area of Science:

• Microbiology
• Biochemistry
• Cellular Biology

Background:

• Treponema phagedenis is a spirochete bacterium.
• The outer envelope (OE) plays a crucial role in bacterial structure and interaction.
• Understanding the OE's chemical makeup is vital for characterizing the bacterium.

Purpose of the Study:

• To elucidate the detailed chemical composition of the outer envelope (OE) of Treponema phagedenis biovar Kazan 5.
• To identify the major molecular components of the OE and their relative abundance.

Main Methods:

• Cultivation of T. phagedenis in a lipid-defined medium.
• Isolation of the OE using sodium dodecyl sulfate.
• Reaggregation of OE components via MgCl2 dialysis.
• Comprehensive chemical analysis including lipid and protein quantification.

Main Results:

• The OE constituted 14.6% of the whole cell dry weight.
• OE composition: 60-73% protein, 1-2% carbohydrate, 4-5% lipid (primarily polar lipid).
• Major polar lipids identified: monogalactosyldiglyceride (43%) and phospholipid (57%), with phosphatidylcholine as the predominant phospholipid.

Conclusions:

• The outer envelope of T. phagedenis biovar Kazan 5 is predominantly protein and polar lipid.
• Peptidoglycan components are absent in the OE, distinguishing it from the whole cell.
• The lipid profile suggests specific membrane characteristics relevant to T. phagedenis biology.