Snail isolation

The modem era of biochemistry and molecular biology has been shaped not least by the isolation and characterization of individual molecules. Recently, however, more and more polyfunctional macromolecular complexes are being discovered, including nonrandomly codistributed membrane-bound proteins [41], These are made up of several individual proteins, which can assemble spontaneously, possibly in the presence of a lipid membrane or an element of the cytoskeleton [42] which are themselves supramolecular complexes. Some of these complexes, e.g. snail haemocyanin [4o], are merely assembled from a very large number of identical subunits vimses are much larger and more elaborate and we are still some way from understanding the processes controlling the assembly of the wonderfully intricate and beautiful stmctures responsible for the iridescent colours of butterflies and moths [44]. 

The magnificent purple pigment referred to in the Bible and known to the Romans as Tyrian purple after the Phoenician port of Tyre (Lebanon), was shown by P. Friedlander in 1909 to be 6,6 -dibromoindigo. This precious dye was extracted in the early days from the small purple snail Murex brandaris, as many as 12000 snails being required to prepare 1.5 g of dye. The element itself was isolated by A.-J. Balard in 1826 from the mother liquors remaining after the crystallization of sodium chloride and sulfate from the waters of the Montpellier salt marshes ... 

The a -, /z-, and a-conotoxins are the best characterized of the peptides isolated from Conus venoms so far. However, a large number of other peptides are found in these venoms. These comprise both paralytic toxins to immobilize the prey of the cone snail, and other biologically active peptides which are not themselves directly paralytic. Only the briefest overview of these peptide components will be presented here. 

Coupland JB. Susceptibility of helicid snails to isolates of the nematode Phasmarhabditis hermaphrodita from southern France. J Inver Path. 1995 66 207-208. 

Xen-2174 (220) (isolated from the snail Conus marmoreus) 13-Amino-acid peptide (a conotoxin) Xen-2174 (220) Neurology (Pain) Inhibits norepinephrine transporter (NET) Phase II (against acute postoperative pain and chronic pain in cancer patient) Xenome 970-973... 

McIntosh M, Cruz LJ, HunkapiUer MW, Gray WR, Ohvera BM. (1982) Isolation and structure of a peptide toxin from the marine snail Conus magus. Arch Biochem Biophys 218 329-334. 

Five isobutylamides were isolated as insect growth inhibitors and toxicants from Fagara macrophylla and identified from their spectroscopic and chemical data. Synthesis and bioassay of the five natural products plus four analogs showed pellitorine to be the most active against a variety of insects, but not against a species of snail. 

Biologically active isobutylamides have been isolated from plants of the Compositae and the Rutaceae. Some of the isohutyla-mides were found to have paralytic and toxic activities against insects, especially when applied topically to several species of Coleopterans and Dipterans.The present work describes the isolation, spectral identification, synthesis, and insect and snail bioassays of five isobutylamides from the Rutaceae plant, Fagara macrophylla. In addition, the synthesis and bioassay of four analogs of the isbbutylamide natural products are described. 

Asturias, J. A., Eraso, E., Arilla, M. C., Gomez-Bayon, N., Inacio, E., and Martinez, A. (2002). Cloning, isolation, and IgE-binding properties of Helix aspersa (brown garden snail) tropomyosin. Int. Arch. Allergy Immunol. 128, 90-96. 

Caiado, J., Lundberg, M., Oman, H., Pedro, E., Pereira-Santos, M., and Periera Barbosa, M. (2007). Isolated snail allergy without house dust mites sensitisation Case report. Allergy 62(Suppl. 83), 218. 

Some dimeric myoglobins have been isolated from the muscles of the sea-snail Nassa mutabilis ind from the clams Anadora broughtonii and A. senilis. These have no Bohr effect but show ooperative effects for the uptake of 02.1274... 

Barry114 isolated a disaccharide, laminaribiose, on the partial hydrolysis of laminarin by enzymes (digestive juice of the snail Helix pomatia or H. aspersa) or by acid (seven hours with N oxalic acid on the water-bath). He showed that this disaccharide consisted solely of D-glucose and considered it to be 3-j3-D-glucopyranosyl-D-glucopyranose (XXIX). 

Historically, 5. japonicum has been considered to be a genetically diverse parasite with different geographic isolates showing variation in snail host specificity (Chiu, 1967), pathogenicity and development (Hsu and Hsu, 1962), morphology (Sobhon et al., 1986) and... 

Suppression-subtractive hybridization (SSH) is another hybridization strategy that is being pursued to examine differential gene expression following parasite infection in the snail host. At least two major laboratories are currently engaged in using this approach towards the isolation of genes that are specifically expressed in either resistant or susceptible snails in response to infection. Initial results from these studies showed differential expression of several transcripts in a resistant (BS-90) and susceptible snail (M-line) in response to... 

Lodes, M.J., Connors, V.A. and Yoshino, T.P. (1991) Isolation and functional characterization of snail hemo-cyte-modulating polypeptide from primary sporocysts of Schistosoma mansoni. Molecular and Biochemical Parasitology 49, 1 -10. 

All of the experimental isolates that retained their decreased sensitivity to praziquantel showed compromised reproductive fitness in the laboratory, expressed most frequently as a decreased cercarial production from snails infected with those isolates compared to controls. For example, the total cercarial production of snails infected with one isolate was only 57% of control isolates (William et al., 2001b). So, despite the presence of some worms more capable of surviving exposure to the recommended therapeutic levels of praziquantel, it is not clear that these worms will provide the genetic stock for an epidemiologically significant core of resistant schistosomes in any of these villages. 

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. 

Cone snails, Conus spp., have been investigated because of their production of conotoxin peptides. From an evolutionary standpoint, the production of conotoxins is quite interesting due to their wide range of neurophysiological activities. The conotoxins are small peptides, 10-30 amino acids, with conformations constrained by multiple disulfide bonds that target a number of receptors in vertebrate and invertebrate nervous systems. Cone snails use these toxins to immobilize prey, which allows the relatively slow-moving cone snails to feed on fish and worms. The wide variety of conotoxins isolated and the hypervariability within peptide sequences has led some to hypothesize a combinatorial biosynthetic approach for the production of conotoxins.116117... 

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