Nanobacteria-like calcite single crystals at the surface of the Tataouine meteorite
AUTOR(ES)
Benzerara, Karim
FONTE
National Academy of Sciences
RESUMO
Nanobacteria-like objects evidenced at the surface of the orthopyroxenes of the Tataouine meteorite in South Tunisia have been studied by scanning and transmission electron microscopies. A method of micromanipulation has been developed to ensure that exactly the same objects were studied by both methods. We have shown that the nanobacteria-like objects are spatially correlated with filaments of microorganisms that colonized the surface of the meteoritic pyroxene during its 70 years of residence in the aridic Tataouine soil. Depressions of a few micrometers in depth are observed in the pyroxene below the carbonates, indicating preferential dissolution of the pyroxene and calcite precipitation at these locations. The nanobacteria-like small rods that constitute calcium carbonate rosettes are well crystallized calcite single crystals surrounded by a thin amorphous layer of carbonate composition that smoothes the crystal edges and induces rounded shapes. Those morphologies are unusual for calcite single crystals observed in natural samples. A survey of recent literature suggests that the intervention of organic compounds derived from biological activity is likely in their formation.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=164604Documentos Relacionados
- Nanobacteria-like particles : a threat to cell cultures
- Chains of magnetite crystals in the meteorite ALH84001: Evidence of biological origin
- Meteorite impact and the mass extinction of species at the Cretaceous/Tertiary boundary
- Hydration of single crystals of dipalmitoylphosphatidylcholine.
- Chemistry at the surfaces of organic crystals