The feeding of escessive amounts of vitamin D to animals causes pathological changes in the skeleton and calcification of soft tissues (l-4). Hypervitaminosis A causes bone fragility. Spontaneous fractures occur in growing rats, whereas in the adult rat only rarefaction develops (5-8). Although excesses of each vitamin cause specific pathological changes, the concomitant feeding of toxic amount...

The cartilaginous endoskeleton of chondrichthyan fishes (sharks, rays, and chimaeras) exhibits complex arrangements and morphologies of calcified tissues that vary with age, species, feeding behavior, and location in the body. Understanding of the development, evolutionary history and function of these tissue types has been hampered by the lack of a unifying terminology. In order to facilitate ...

In zooxanthellate corals, the photosynthetic fixation of carbon dioxide and the precipitation of CaCO3 are intimately linked both spatially and temporally making it difficult to study carbon transport mechanisms involved in each pathway. When studying Tubastrea aurea, a coral devoid of zooxanthellae, we can focus on carbon transport mechanisms involved only in the calcification process. We perf...

BACKGROUND Adequate calcium intake is known to protect the skeleton. However, studies that have reported adverse effects of calcium supplementation on vascular events have raised widespread concern. OBJECTIVE We assessed the association between calcium intake (from diet and supplements) and coronary artery calcification, which is a measure of atherosclerosis that predicts risk of ischemic hea...

Ocean acidification (OA) impacts the physiology of diverse marine taxa; among them corals that create complex reef framework structures. Biological processes operating on coral reef frameworks remain largely unknown from naturally high-carbon-dioxide (CO2) ecosystems. For the first time, we independently quantified the response of multiple functional groups instrumental in the construction and ...

Despite the importance of stony corals in many research fields related to global issues, such as marine ecology, climate change, paleoclimatogy, and metazoan evolution, very little is known about the evolutionary origin of coral skeleton formation. In order to investigate the evolution of coral biomineralization, we have identified skeletal organic matrix proteins (SOMPs) in the skeletal proteo...

This study was designed to investigate the effect of light and temperature on Sr/Ca and Mg/Ca ratios in the skeleton of the coral Acropora sp. for the purpose of evaluating temperature proxies for paleoceanographic applications. In the first experiment, corals were cultivated under three light levels (100, 200, 400 lmol photons m 2 s ) and constant temperature (27 C). In the second experiment, ...

Ocean acidification (OA) and thermal stress may undermine corals' ability to calcify support diverse reef communities, particularly in marginal environments. Coral calcification depends on aragonite supersaturation (? » 1) of the calcifying fluid (cf) from which skeleton precipitates. Corals actively upregulate pHcf relative seawater buffer against changes temperature dissolved inorganic carbon...

Biomineralized tissues are widespread in animals. They are essential elements in skeletons and in statocysts. The function of both can only be understood with respect to gravitational force, which has always been present. Therefore, it is not astonishing to identify microgravity as a factor influencing biomineralization, normally resulting in the reduction of biomineralized materials. All known...

Biomineralization, the biologically controlled formation of mineral deposits, is of widespread importance in biology, medicine, and engineering. Mineralized structures are found in most metazoan phyla and often have supportive, protective, or feeding functions. Among deuterostomes, only echinoderms and vertebrates produce extensive biomineralized structures. Although skeletons appeared independ...