Of mollusk

Most aquatic invertebrates have very little capacity for metabolism this is particularly true of mollusks. Crustaceans (e.g., crabs and lobsters) appear to have greater metabolic capability than mollusks (see Livingstone and Stegeman 1998 Walker and Livingstone 1992). 

Figure 1. Histogram of measurements of molar U/Ca ratio in a number of samples of reef-building corals and one giant clam sample (after Edwards 1988). Also indicated is the U/Ca ratio of seawater. This illustrates the point that corals do not fractionate U from Ca by large amounts when they make their skeletons. U/Ca ratios of corals are similar to values from inorganically precipitated marine aragonite. Mollusks along with most other biogenic minerals exclude uranium. Note that the horizontal axis is on a log scale and that the U/Ca ratio of the clam is almost 5 orders of magnitude lower than that of the corals. This difference is the fundamental reason why there are difficulties with uranium-series dating of mollusks.

Tyrian purple was derived from the "purple snail," the common name for what, in reality, are several species of mollusks of the genus Murex. Each one of the mollusk species yielded a slightly different variety of purple. In Tyre, where the most prized purple dye was produced, Murex brandaris snails were those most abundant and generally used, while in Sidon, not far to the north of Tyre, an amethyst purple variety of the dye was obtained from... 

Production of these aldehydes from algal-derived caulerpenyne (54) was thought to be carried out by the mollusk [123,124], but since the alga has been found to perform this transformation, re-investigation of the biosynthesis of this metabolite in mollusks is advised. The impressive ability of mollusks to ex-... 

Early natural product research with marine mollusks supported a conclusion that all secondary metabolites of mollusks are diet-derived, which proved to be premature. In fact, the biosynthetic capability of some marine mollusks covers a wide spectrum of chemical classes and substances. Much of this recent insight has resulted from work in the laboratories of the authors of Chapter 3. 

Greig, R.A. 1979. Trace metal uptake by three species of mollusks. Bull. Environ. Contam. Toxicol. 22 643-647. 

The dust from mollusk shells can also provoke occupational allergies. Inhalation of mollusk shell dust in a nacre button factory was associated with h)q)ersensitivity pneumonitis (Orriols et ah, 1990, 1997). A similar case was identified in Korea (Kim et ah, 1982). Several Japanese investigators have described occupational asthma occurring among workers who culture oysters (Nakashima, 1969 Wada et ah, 1967). Exposure to dust from mofher-of-pearl in a souvenir maker (Tas, 1972) and fo cuttlefish bones in a jewelry polisher (Beltrami et ah, 1989) was linked to occupational asthma. 

Chemical bias toward certain molecular arrangements may also determine the commonness of certain metabolites (Pietra 1995), such as the aplysinopsins (indole alkaloids of many sponges, cnidarians, and mollusks. Chart 8.2. A), bis-indole and guanidine alkaloids (Chart 8.2.A), isoprenoids (Pietra 1995, Chart 8.2.1), and polypropionates of mollusks, sponges, and fungi (Chart 8.2.FA/PO). 

Com shell is carnivorous snail belongs to the world s largest genus of marine invertebrates (Conus) under the phylum of mollusks (Bingham et al., 2010). Com shell species are able to secrete venom, which contains com shell toxins (conotoxins) of bioactive peptides called as conopeptides (Layer and McIntosh, 2006). Different structural classes of... 

The hard integument of mollusks and crustaceans, consisting mostly of calcium carbonate, chitdn, etc,... 

These geochemical tracers have been successfully applied to studies of the shells of a variety of marine organisms including bivalve and gastropod mollusks, ostracods, forams, brachiopods and solitary corals (47, 54, 57, 58). In the case of mollusk shells, for example, serial microsampling around the spiral whorls from earliest to oldest growth revealed sinusoidal variations in isotope ratios, which result from shell deposition in a seasonal environment (47, 50, 62-64). Our previous work showed this to be true of Olivella shells as well, where 8,sO levels fluctuate from warm summer temperatures to cold spring and winter temperatures (38). 

Stored DDT and dieldrin present in lake trout eggs at spawning time can affect the ultimate survival of the young (ref. 82c). Oyster growth is inhibited even at low concentrations of DDT. This characteristic growth sensitivity of a number of mollusks to DDT, and the rates at which DDT is flushed out when the mollusk is transferred to fresh water, has been used as a pesticide monitoring tool (Butler, ref. 82d). 

Weiner, S., and Traub, W. "X-ray-diffraction study of the insoluble organic matrix of Mollusk shells". FEBS Lett. 111(2), 311-316 (1980). 

Keith, M. L., G. M. Anderson, and R. Eichler Carbon and oxygen isotopic composition of mollusk shells from marine and fresh-water environments. Geochim. cosmochim. Acta 28, 1757 (1964). 

The continental slope represents a transit zone of the sediment fluxes supplied in the form of detrital matter from the rivers and the products of abrasion, as well as the sediments carried by turbidity flows. The continental slope is covered with compacted clayey oozes (grain-size fractions of 0.001-0.01 mm). At selected places on steeper parts of the slope, remains of mollusk fauna such as shells of Dreissena rostriformis have been encountered. At sites with gentle sloping, they are overlain by the Holocene and recent sediments [11]. 

In 1995-1997, the studies of benthos in the northeastern part of the Black Sea showed a significant excess of the rapa whelk biomass over the biomass of other species of mollusks. In the Arkhipo-Osipovka-Kerch Strait region, the biomass of edible benthos was only 12 gm2. The deterioration in the condition of food resources also affected the condition of benthofagous fishes. Only the Black Sea red mullet gut content mollusks were found. In the food of other fishes, benthos made up from 1 to 20% [62],... 

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