Biomagnification
Mostrando 13-19 de 19 artigos, teses e dissertações.
-
13. Análise da resposta antioxidativa de células de Nicotiana tabacum cv BY-2 submetidas ao cádmio. / Antioxidant response of by-2 Nicotiana tabacum cells to cadmium stress.
The contamination of environments by heavy metal pollution, mainly by cádmium (Cd), considered one of the more toxic, is generated by mining and industrial activities, and sewage sludge and phosphated fertilizers used in agriculture. The latter contains Cd in its composition and with continuous agricultural utilization an increase in the heavy metals levels
Publicado em: 2004
-
14. DDT (dicloro difenil tricloroetano): toxicidade e contaminação ambiental - uma revisão
DDT and others organochlorine insecticides are very persistent substances. Clinical symptoms of intoxication have been reported in humans, although the main problem concerning such substances is bioaccumulation and biomagnification along throphic chains, leading to contamination of top predators and humans after them. In this review these characteristics are
Química Nova. Publicado em: 2002-11
-
15. Biomagnification of cyanobacterial neurotoxins and neurodegenerative disease among the Chamorro people of Guam
We here report biomagnification (the increasing accumulation of bioactive, often deleterious molecules through higher trophic levels of a food chain) of the neurotoxic nonprotein amino acid β-methylamino-l-alanine (BMAA) in the Guam ecosystem. Free-living cyanobacteria produce 0.3 μg/g BMAA, but produce 2-37 μg/g as symbionts in the coralloid roots of cyc
National Academy of Sciences.
-
16. Biomagnification of Aroclor 1242 in Decomposing Spartina Litter †
The accumulation of a polychlorinated biphenyl (PCB) mixture (Aroclor 1242) in the process of detritus formation by a shredded marshgrass (Spartina alterniflora) under aerobic conditions was monitored in percolators for 4 months at 20°C. Dissolved PCB in the influent solution was 14 to 16 μg/liter. Parameters monitored in addition to PCB accumulation were
-
17. A mechanism for slow release of biomagnified cyanobacterial neurotoxins and neurodegenerative disease in Guam
As root symbionts of cycad trees, cyanobacteria of the genus Nostoc produce β-methylamino-l-alanine (BMAA), a neurotoxic nonprotein amino acid. The biomagnification of BMAA through the Guam ecosystem fits a classic triangle of increasing concentrations of toxic compounds up the food chain. However, because BMAA is polar and nonlipophilic, a mechanism for it
National Academy of Sciences.
-
18. Biomagnification of p, p′-DDT and Methoxychlor by Bacteria
Aerobacter aerogenes and Bacillus subtilis accumulated p, p′-DDT and methoxychlor directly from water. Uptake of both 14C-labeled organochlorine insecticides was rapid; 80 to 90% of the 24-h residues were reached within 30 min. Total cellular residues varied linearly with concentrations of DDT and methoxychlor in water ranging from 0.5 to 5.0 μg/liter. Th
-
19. Accumulation of selenium in a model freshwater microbial food web.
The transfer of selenium between bacteria and the ciliated protozoan, Paramecium putrinum, was examined in laboratory cultures. The population growth of the ciliate was not inhibited in the presence of the highest concentrations of dissolved selenite or selenate tested (10(3) micrograms liter-1). Experiments with radioactive 75selenite or 75selenate indicate