Snail gastropods

Copper compounds are used routinely and widely to control freshwater snails that serve as intermediate vectors of schistosomiasis and other diseases that afflict humans (Hasler 1949 NAS 1977 Rowe and Prince 1983 Winger etal. 1984 Al-Sabri etal. 1993). These compounds include copper sulfate, copper pentachlorophenate, copper carbonate, copper-tartaric acid, Paris green (copper arsenite-acetate), copper oxide, copper chloride, copper acetyl acetonate, copper dimethyl dithiocar-bamate, copper ricinoleate, and copper rosinate (Cheng 1979). Also, many species of oyster enemies are controlled by copper sulfate dips. All tested species of marine gastropods, tunicates, echinoderms, and crabs that had been dipped for 5 seconds in a saturated solution of copper sulfate died if held in air for as little as a few seconds to 8 h mussels, however, were resistant (MacKenzie 1961). 

Gastropods (snails), echinoderms (sea urchins and sea stars) and annelids (lugworms) were exposed to oil saturated sediments and assayed for AHH activity (17). Sediment was mixed with Venezuelan crude at a concentration of 0.2-0.5% and exposures were for one week (4°C) in a static system with water renewal at 2-3 day intervals. The aim was to determine if oil soaked sediments could induce AHH activity in some representative intertidal benthic organisms common to the subarctic waters of the North West Atlantic. Digestive gland homogenates from snails, sea urchins, and sea stars and a combination of intestinal and gill tissues from annelids were used in the enzyme assays. 

Aqueous and sedimentary TBT and TFT cause chronic and acute effects in algae, zooplankton, Crustacea, mollusks, fish, and animals. These effects have been local in nature, occurring mostly in harbors near industrialized lands. TBT is bioaccumulated in many species, which is unfortunate as it is a potent endocrine disrupter. The enrichment factor in mussels, snails, and oysters ranges from 10,000 to 60,000. As mentioned in Section 28.7.1, TBT induces imposex in marine gastropods. 

The gastropods account for the majority of chemistry reported for the phylum. Of the total reported for the phylum, 497 (86%) were isolated from the class Gastropoda. The subclass Opistho-branchia accounts for 378 compounds, 76% of the total reported from gastropods. More specifically, 317 compounds (55%) were isolated from nudibranchs and sea hares. For the order Nudibranchia, 159 compounds have been reported, of which 137 (86%) are isoprenoids. The subclass Prosobran-chia (snails) is one of the few groups that have yielded mainly amino acid derived compounds. A total of 72 compounds have been reported for prosobranchs, and 51% are derived from amino acids. A large number of groups within the phylum are underrepresented statistically with respect to reported chemistry. 

Herbivores in the sea are phylogenetically more diverse than on land. Seaweeds are eaten by diverse vertebrate ectotherms and an array of invertebrate consumers that vary both in their selectivity and in their impact on algae. Vertebrate herbivores are comprised of various fish families and species, as well as some turtles.24 111 120 125 Invertebrate herbivores span at least four different phyla and include an array of gastropods (such as snails, limpets, sacoglossans, sea hares, cephalaspideans, and chitons), urchins, crabs, amphipods, isopods, shrimps, polychaete worms, copepods, and a few insect species that feed on algae living in the upper littoral zone.24 110 123 126-135... 

Grazing marine gastropods that inhabit rocky substrata, including trochaceans, limpets, and keyhole limpets, are easily induced to metamorphose by small pieces of rocky substratum naturally coated with complex films of bacteria, microalgae, and probably fungi.182 It is likely that such induction is widespread in these groups of snails. 

Mollusks Gastropods Abalone, snail, whelk GI symptoms, larygoedema Tropomyosin ... 

There are seven living classes of molluscs,23 including the worm-like Aplacophora, the chitons of the Polyplacophora, the limpet-like creatures of the Monoplacophora and the Gastropods which includes the abalone, marine snails, slugs, nudibranchs and conch. The next three are comprised of the Cephalopods (cuttlefish, squid and octopus), the Bivalves (clams, oysters) and the Scaphopoda (Tusk shells). Figure 6.5 shows that the most prolific order within Mollusca is the Aplysiomorpha (Anaspidea) with 507 articles and 384 structures published since 1951. There have been a total of 1684 publications and 1225 chemical structures reported from the order Mollusca. One of the most well-known structure classes from molluscs are the dolastatins, which are from the Anaspidea order. 

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