Consulta: creatorFacets:"Farina,Marcos"
Registros recuperados: 3
Data/hora: 26/07/2024 22:55:07

Crystal habits and magnetic microstructures of magnetosomes in coccoid magnetotactic bacteria
Provedor de dados: Anais da Academia Brasileira de Ciências
Autores: Lins,Ulysses; McCartney,Martha R.; Farina,Marcos; Frankel,Richard B.; Buseck,Peter R.
We report on the application of off-axis electron holography and high-resolution TEM to study the crystal habits of magnetosomes and magnetic microstructure in two coccoid morphotypes of magnetotactic bacteria collected from a brackish lagoon at Itaipu, Brazil. Itaipu-1, the larger coccoid organism, contains two separated chains of unusually large magnetosomes; the magnetosome crystals have roughly square projections, lengths up to 250 nm and are slightly elongated along [111] (width/length ratio of about 0.9). Itaipu-3 magnetosome crystals have lengths up to 120 nm, greater elongation along [111] (width/length ~0.6), and prominent corner facets. The results show that Itaipu-1 and Itaipu-3 magnetosome crystal habits are related, differing only in the...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Magnetite; Magnetotaxis; High-resolution transmission electron microscopy.
Ano: 2006
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652006000300007

Simple homemade apparatus for harvesting uncultured magnetotactic microorganisms
Provedor de dados: Brazilian Journal of Microbiology
Autores: Lins,Ulysses; Freitas,Flavia; Keim,Carolina Neumann; Barros,Henrique Lins de; Esquivel,Darci Motta S.; Farina,Marcos.
A simple apparatus for harvesting uncultured magnetotactic microorganisms is described. This apparatus consists of a glass container with two openings. A large opening on the topside is used to introduce the sediment and water. The sediment and water are previously stored in loosely capped bottles previously tested for the presence of magnetotactic bacteria. The apparatus is exposed to a properly aligned magnetic field of a homemade coil and the bacteria are removed through the capillary end of the second opening of the container. Harvested bacteria can then be used to ultrastrucutral studies using electron spectroscopic imaging. Large numbers of magnetotactic bacteria consisting of cocci and rod-shaped cells were efficiently collected from different...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Magnetotactic bacteria; Harvesting uncultured bacteria; Electron microscopy.
Ano: 2003
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1517-83822003000200004

Zinc detoxification by a cyanobacterium from a metal contaminated bay in Brazil
Provedor de dados: Brazilian Archives of Biology and Technology
Autores: Andrade,Luciana; Keim,Carolina N.; Farina,Marcos; Pfeiffer,Wolfgang C.
We describe here the trapping of zinc in polyphosphate granules of the cyanobacterium Synechocystis aquatilis NPBS-3. Cells were cultured in 25 µM of zinc chloride and prepared for electron microscopy and energy-dispersive X-ray analysis. Some ultrastructural features were changed by zinc exposure, the increase of glycogen granules number being the main change. The polyphosphate granules contained phosphorus, sulphur, calcium, iron and zinc. The trapping of zinc in polyphosphate granules seemed to be an effective way of detoxifying the metal and surviving in the bay. As a non-specific mechanism, these polyphosphate granules could also be effective in trapping other metals in excess.
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Heavy metals; Zinc; Sepetiba Bay; Polyphosphate granules; Glycogen granules; Detoxification.
Ano: 2004
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132004000100020