| Full text | |
| Author(s): |
Cristina Souza Freire Nordi
[1]
;
Thays Gabrielle Wenzel Ferreira Cavagliere
[2]
;
Armando Augusto Henriques Vieira
[3]
;
Otaciro Rangel Nascimento
[4]
Total Authors: 4
|
| Affiliation: | [1] Universidade de São Paulo. Instituto de Física de São Carlos - Brasil
[2] Universidade de São Paulo. Instituto de Física de São Carlos - Brasil
[3] Universidade Federal de São Carlos. Departamento de Botânica - Brasil
[4] Universidade de São Paulo. Instituto de Física de São Carlos - Brasil
Total Affiliations: 4
|
| Document type: | Journal article |
| Source: | Acta Botanica Brasilica; v. 20, n. 2, p. 449-454, 2006-06-00. |
| Field of knowledge: | Biological Sciences - Botany |
| Abstract | |
The aim of this study was to investigate the role of chaotropic effect of Li+ on the polysaccharide sheath of the microalga Ankistrodesmus gracilis (Chlorophyceae, Chlorococales) in the selective permeability and transport of molecules in the interior of the cell. The colonial microalga Ankistrodesmus gracilis has a relatively large and continuous mucilaginous sheath. The Electron Paramagnetic Resonance (EPR) was applied using the spin label- Tempo 2,2,6,6-tetramethylpiperidine-1-oxyl of non-reactive nature to study its diffusion coefficients across the polysaccharide envelope. The EPR technique is used to monitor the spin labels diffusion time across the polysaccharide capsule, cell wall and membrane into the interior of the cell, where they lose their paramagnetic properties. The lithium ion (Li+) has the property to structurally disorganize the polysaccharide capsule and the spin label diffusion changes producing different spin label time decay. The time decays of cells subjected to Li+ treatment are faster than the cells without this ion usage and the decay time decreases with increasing Li+ concentration. The photomicrographies show the complete removal of the cell capsule from LiCl 1,0 M upward and as a result, the algal cells agglutinate producing cell clumps, and the algal cells are clearly died. (AU) | |
| FAPESP's process: | 99/07766-0 - The production and fate of algal extracellular polysaccharides in an eutrophic reservoir of the Tietê River, SP, Brazil |
| Grantee: | Armando Augusto Henriques Vieira |
| Support Opportunities: | Research Projects - Thematic Grants |