Effect of short-time exposures to nickel and lead on brain monoamine oxidase from Danio rerio and Poecilia reticulata.

The aim of this work was to verify, in two small size freshwater teleosts Danio rerio and Poecilia reticulata, the effects of short-time exposures (24 and 72 h) to a sublethal dose (500 microg/L) of nickel and lead, on brain monoamine oxidase (MAO), an important neural enzyme. The 24-h treatment using both metals caused a strong reduction of MAO activity in D. rerio brain, whereas causing a slight MAO activity stimulation in P.

Molecular characterization of monoamine oxidase in zebrafish (Danio rerio).

Monoamine oxidase (MAO) is responsible for the degradation of a number of neurotransmitters and other biogenic amines. In terrestrial vertebrates, two forms of the enzyme, named MAO A and B, were found in which mammals are coded by two similar but distinct genes. In teleosts, the biochemical data obtained so far indicate that enzyme activity is due to a single form, whose sequence, obtained for trout, displays 70% identity with mammal MAO A and B.

Monoamine oxidase expression during development and aging.

Monoamine oxidase (MAO) isoenzymes play a major role in regulating the concentration of several bioactive amines, including serotonin and catecholamines. Both in the nervous system and in peripheral organs, MAOs can potentially modulate all the processes involving these bioactive amines. In the present article, we review some of the most significant articles published so far on changes in MAOs during development and aging.

Monoamine oxidase A and B activities in embryonic chick hepatocytes: differential regulation by retinoic acid.

Monoamine oxidases (MAOs) A and B are two isoenzymes involved in the degradation of many biological amines in the nervous system and in peripheral organs. In the present work hepatocytes isolated from 14-day-old chick embryos were used as a model system to determine whether retinoic acid (RA) is capable of modulating the activity of the two MAO forms. RA is a retinoid that, by binding with nuclear receptors, interferes with the expression of specific genes in many differentiation processes.

Deprenyl, an Inhibitor of Monoamine Oxidase B, Delays the First Two Mitotic Cycles of Sea Urchin eggs: (deprenyl/mitotic cylcle/sea urchin).

Sea urchin eggs are known to display a significant level of monoamine oxidase B activity. Deprenyl, a highly selective inhibitor of monoamine oxidase B, was found to prolong the length of the first two mitotic cycles of the sea urchin egg. The prophase seems to be specifically prolonged by the drug, while the length of the other phases of the cycle is unaffected.

Protein Synthetic Activities during Spermiogenesis in the Sea Urchin: An high Resolution Autoradiographic Study of H-Leucine Incorporation: (sea urchins/spermiogenesis/protein synthesis).

Protein synthetic activity has been studied during spermiogenesis of Paracentrotus lividus by high-resolution autoradiography using H-leucine as a labeled precursor. Under the adopted experimental conditions H-leucine is incorporated during the whole spermiogenesis period. The early spermatid is the most active stage and it shows labeling over the nucleus, the cytosol and the mitochondria.

On the fine Structure of Paracentrotus Lividus Permanent Blastulae Obtained after Treatment with 5-Bromodeoxyuridine: (5-bromodeoxyuridine/sea urchin embryos/ultrastructure).

This work reports some observations on the fine structure of the different types of Paracentrotus lividus permanent blastulae obtained after treatment with BUdR. Some permanent blastulae appeared similar to normal early mesenchyme blastulae and at the ultrastructural level they did not show any particular differences compared with the normal embryos. The only remarkable fact was that nucleoli often displayed the fibrous portion still abundant.