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Cell wall-less, free-living spirochetes in Antarctica
1Cooperative Research Centre for the Antarctic and Southern Ocean Environment, University of Tasmania, Hobart, Australia.
FEMS Microbiology Letters
|October 15, 1992
Summary
Phylogenetic analysis revealed an Antarctic, cell wall-less bacterial strain, phenotypically resembling Anaeroplasma, actually belongs to the Spirochaetales order. This finding challenges previous assumptions about Spirochaetales morphology and viability of wall-less forms.
Area of Science:
- Microbiology
- Bacterial Phylogenetics
- Antarctic Microbiology
Background:
- The order Spirochaetales was characterized by a uniform cell morphology, with phylogeny generally reflected in morphology.
- Cell wall-less bacteria are known in various bacterial groups, but their presence and implications in Spirochaetales were not well-established.
Purpose of the Study:
- To determine the phylogenetic placement of a unique, cell wall-less Antarctic bacterial strain.
- To investigate the implications of this finding on the understanding of Spirochaetales diversity and characteristics.
Main Methods:
- DNA extraction and purification from the Antarctic bacterial strain.
- Polymerase Chain Reaction (PCR) amplification of the 16S ribosomal DNA (rDNA) gene.
- Sequencing of the amplified 16S rDNA and phylogenetic analysis using comparative sequence analysis against public databases.
Main Results:
- Phylogenetic analysis placed the Antarctic strain within the order Spirochaetales, despite its cell wall-less phenotype.
- The strain exhibited phenotypic similarities to the genus Anaeroplasma, highlighting a discrepancy between phenotype and phylogeny.
- This discovery indicates that Spirochaetales can include cell wall-less members, challenging the order's previously uniform morphological characteristic.
Conclusions:
- The phylogenetic placement of this Antarctic strain significantly expands the known diversity within the Spirochaetales.
- The existence of cell wall-less spirochetes necessitates a re-evaluation of the morphological uniformity within this bacterial order.
- Further research is warranted to explore the viability and ecological roles of wall-less spirochetes and their potential implications in spirochetal infections.