Encontrados 9 documentos, a visualizar página 1 de 1
Comparative study of tributyltin toxicity on two bacteria of the genus Bacillus
Martins, J. D.; Jurado, A. S.; Moreno, A. J. M.; Madeira, V. M. C.Tributyltin is a potent biocide mainly used in marine antifouling paints. Owing to its widespread distribution in coast areas and its high toxicity to aquatic organisms, the use of this compound is generally restricted and under government regulation. Despite of that, it persists in the aquatic environment. Organotins used in industry have also been detected in terrestrial environments. The persistence and high...
Toxicity of methoprene as assessed by the use of a model microorganism
Monteiro, J. P.; Jurado, A. S.; Moreno, A. J. M.; Madeira, V. M. C.Methoprene is an insect juvenile growth hormone mimic, commonly used as a pesticide. Although widely used for the control of several pests, toxic effects on organisms of different phyla have been reported. These events triggered studies to clarify the mechanisms of toxicity of this insecticide putatively involved in ecological issues. Here we show the effect of methoprene on the normal cell growth and viability...
Use of the microorganism Bacillus stearothermophilus as a model to evaluate tox...
Martins, J. D.; Monteiro, J. P.; Antunes-Madeira, M. C.; Jurado, A. S.; Madeira, V. M. C.Microorganisms are very powerful tools for the supply of information about the toxic effects of lipophilic compounds, since an impairment of cell growth usually occurs as a result of perturbations related, in most cases, with the partition of toxicants in membranes. The thermophilic eubacterium Bacillus stearothermophilus has been used as a model system to identify [alpha]- and [beta]-endosulfan interactions wi...
Molecular mechanisms of the metabolite 4-hydroxytamoxifen of the anticancer dru...
Monteiro, J. P.; Martins, J. D.; Luxo, P. C.; Jurado, A. S.; Madeira, V. M. C.A strain of the thermophilic eubacterium Bacillus stearothermophilus was used as a model system to identify membrane mediated cytotoxic effects of 4-hydroxytamoxifen, following previous studies with tamoxifen. With this experimental approach we attempted to further clarify tamoxifen and 4-hydroxytamoxifen membrane interactions often evoked as responsible for their multiple cellular effects. Bacterial growth and...
Chromium(VI) interaction with plant and animal mitochondrial bioenergetics: A c...
Fernandes, M. A. S.; Santos, M. S.; Alpoim, M. C.; Madeira, V. M. C.; Vicente, J. A. F.The mechanism of Cr(VI)-induced toxicity in plants and animals has been assessed for mitochondrial bioenergetics and membrane damage in turnip root and rat liver mitochondria. By using succinate as the respiratory substrate, ADP/O and respiratory control ratio (RCR) were depressed as a function of Cr(VI) concentration. State 3 and uncoupled respiration were also depressed by Cr(VI). Rat mitochondria revealed a ...
Hydroxytamoxifen interaction with human erythrocyte membrane and induction of p...
Cruz Silva, M. M.; Madeira, V. M. C.; Almeida, L. M.; Custódio, J. B. A.4-Hydroxytamoxifen (OHTAM) is the most active metabolite of the widely prescribed anticancer drug tamoxifen (TAM) used in breast cancer therapy. This work describes the effects of OHTAM on isolated human erythrocytes, using standardized test conditions, to check for a putative contribution to the TAM-induced hemolysis and to study basic mechanisms involved in the interaction of OHTAM with cell membranes. Incuba...
Mitochondrial permeability transition induced by the anticancer drug etoposide
Custódio, J. B. A.; Cardoso, C. M. P.; Madeira, V. M. C.; Almeida, L. M.Etoposide (VP-16) is widely used for the treatment of several forms of cancer. The cytotoxicity of VP-16 has been assigned to the induction of apoptotic cell death but the signaling pathway for VP-16-induced apoptosis is essentially unknown. There is some evidence that this process depends on events associated with the loss of mitochondrial membrane potential ([Delta][Psi]) and/or release of apoptogenic factors...
Toxic effects of tamoxifen on the growth and respiratory activity of Bacillus s...
Luxo, C.; Jurado, A. S.; Custódio, J. B. A.; Madeira, V. M. C.The anticancer drug tamoxifen (TAM) is used as first line therapy in breast cancer. Although tamoxifen is usually considered an estrogen antagonist, several studies suggest alternative mechanisms of action. Bacillus stearothermophilus has been used as a model to clarify the antiproliferative action of tamoxifen putatively related with drug-membrane interaction. According to previous data, TAM induces perturbati...
Cytotoxicity and Membrane Interaction of Tamoxifen as Affected by Ca2+ and Mg2+...
Luxo, C.; Jurado, A. S.; Madeira, V. M. C.A strain of Bacillus stearothermophilus was used as a model to study the interaction of tamoxifen (TAM) with the membrane and the cytostatic antiproliferative effects not related to estrogen binding. TAM inhibits the growth of B. stearothermophilus as a function of concentration. The supplementation of the growth medium with Ca2+ or Mg2+ partially relieves the growth inhibition by TAM, allowing growth at TAM co...
| Financiadores do RCAAP | |||||||
|
|
|
|
|
|
||