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Composite, large spirochetes from microbial mats: spirochete structure reviewPhenomena previously unknown in free-living spirochetes are reported: large-sized cells with variable diameter (length to 100 microns, width between 0.4 and 3.0 microns), composite structure (smaller spirochetes inside larger ones), and positive phototropic behavior. These bacteria, Spirosymplokos, are compared with all other spirochete genera. The large spirochete, grown in mixed culture, was studied live and by transmission EM. The protoplasmic cylinder was replete with spherical granules 20-32 nm in diameter, and three to six periplasmic 26-nm flagella were inserted subterminally. Comparably granulated and flagellated small spirochetes were located inside the protoplasmic cylinder and in the periplasm of the large ones. When exposed to air, movement became erratic, protoplasmic cylinders retracted to lie folded inside the outer membrane, and refractile membranous structures formed. From one to four structures per still-moving spirochete were seen. Spirosymplokos was enriched from laboratory samples exposed to oxygen-rich and desiccating, but not dry, conditions for at least 4 mo after removal of microbial mat from the field.
Document ID
20050000440
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Margulis, L.
(University of Massachusetts Amherst 01003)
Ashen, J. B.
Sole, M.
Guerrero, R.
Date Acquired
August 22, 2013
Publication Date
August 1, 1993
Publication Information
Publication: Proceedings of the National Academy of Sciences of the United States of America
Volume: 90
Issue: 15
ISSN: 0027-8424
Subject Category
Life Sciences (General)
Distribution Limits
Public
Copyright
Other
Keywords
NASA Discipline Exobiology
NASA Discipline Number 52-30
NASA Program Exobiology
Non-NASA Center

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