Vertebrates mammals

Hydroxyapatite vertebrates, mammals, fish Octacalcium phosphate vertebrates Amorphous SiO limpets, chitons Magnetite chitons Goethite fimpets Phosphoferrite chitons... 

Vertebrates Mammals Study skins, pelts, mounted specimens (taxidermy), whole or partial skeletons, teeth, wet-preserved animals, parts, or stomach contents, eggs, nests Ivory, ruminant horn, rhino horn, antler, bone, claws, skin (leather, vellum), hair (bristles, quills, fur) hooves... 

The light-sensitive cell survival pathways of some ancestral fungal eukaryota (Neurospora) remain conserved in vertebrate mammals and are found to be functional in the human pineal gland without or with its immortalized transformation vide infra). 

Immature forms of vertebrates— mammal, bird, and reptile embryos up to the last third of their gestation or incubation period, larval forms of amphibians and fish imtil the stage where they become capable of independent feeding, and cephalopods imtil the point at which they hatch. 

Several years ago, it was discovered that the thyroid gland was also the source of a hypocalcemic hormone having effects in general opposition to those of the parathyroid hormone. This hormone is produced in mammals by the parafollicular C-ceUs and in other vertebrates by the ultimobrachial bodies (45). Originally called thyrocalcitonin, it is now referred to as calcitonin (CT). 

Birds and mammals are endothermic vertebrates. Not coincidentally, they are the only vertebrates with unique external body coverings—feathers and hair, respectively. For both groups, these body coverings evolved as an adaptation to reduce heat loss. A bird s feathers were originally adaptive because they helped keep the animal warm, not because they helped it to fly. 

Many of the phase 1 enzymes are located in hydrophobic membrane environments. In vertebrates, they are particularly associated with the endoplasmic reticulum of the liver, in keeping with their role in detoxication. Lipophilic xenobiotics are moved to the liver after absorption from the gut, notably in the hepatic portal system of mammals. Once absorbed into hepatocytes, they will diffuse, or be transported, to the hydrophobic endoplasmic reticulum. Within the endoplasmic reticulum, enzymes convert them to more polar metabolites, which tend to diffuse out of the membrane and into the cytosol. Either in the membrane, or more extensively in the cytosol, conjugases convert them into water-soluble conjugates that are ready for excretion. Phase 1 enzymes are located mainly in the endoplasmic reticulum, and phase 2 enzymes mainly in the cytosol. 

Unchanged p,p -DDT tends to be lost only very slowly by land vertebrates. There can, however, be a certain amount of excretion by females into milk or across the placenta into the developing embryo (mammals) or into eggs (birds, reptiles, and insects). 

Mechanistic studies have shown that TBT and certain other forms of trialkyltin have two distinct modes of toxic action in vertebrates. On the one hand they act as inhibitors of oxidative phosphorylation in mitochondria (Aldridge and Street 1964). Inhibition is associated with repression of ATP synthesis, disturbance of ion transport across the mitochondrial membrane, and swelling of the membrane. Oxidative phosphorylation is a vital process in animals and plants, and so trialkyltin compounds act as wide-ranging biocides. Another mode of action involves the inhibition of forms of cytochrome P450, which was referred to earlier in connection with metabolism. This has been demonstrated in mammals, aquatic invertebrates and fish (Morcillo et al. 2004, Oberdorster 2002). TBTO has been shown to inhibit P450 activity in cells from various tissues of mammals, including liver, kidney, and small intestine mucosa, both in vivo and in vitro (Rosenberg and Drummond 1983, Environmental Health Criteria 116). 

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