Information resources on the care and use of molluscs

Abstract

Softshell clams (Mya arenaria) were exposed to dioxin in controlled laboratory experiments in order to study their molecular response to dioxin exposure. A complementary DNA (cDNA) fragment with sequence similarity to E3 ubiquitin protein ligase appeared to be upregulated in dioxin exposed clams compared to controls. E3 covalently ligates ubiquitin onto a protein, targeting it for degradation. Our findings suggest that the ubiquitin mediated proteolytic pathway in the softshell clam may be activated by dioxin exposure. Because the clam E3 predicted amino acid sequence is most similar to a specific vertebrate E3 protein (E6 AP), we hypothesize that dioxin may stimulate ubiquitin mediated degradation of cell cycle regulatory proteins, such as the tumor suppressor p53, which promotes cell proliferation. This pathway has been observed in human cervical cancer. Partial cDNA sequence of the clam E3 has been identified using the differential display polymerase chain reaction (ddPCR) and RACE (Rapid Amplification of cDNA Ends) PCR; the full length sequence is currently being determined. Discovering the molecular mechanism(s) stimulated by dioxin exposure in this invertebrate model may contribute to a better understanding of the effects of dioxin on marine organisms. Descriptors: clams enzymology, ligases metabolism, amino acid sequence, clams drug effects, dioxins toxicity, mice, molecular sequence data, random amplified polymorphic DNA technique veterinary, water pollutants, chemical toxicity. Kono, M.; Hayashi, N.; Samata, T. (2000) Molecular mechanism of the nacreous layer formation in Pinctada maxima. Biochem Biophys Res Commun 269(1): 213 8, ISSN: 0006 291X. NAL call no: 442.8 B5236 Abstract: We have cloned the cDNAs that encode two kinds of molluscan shell matrix proteins, namely N66 and N14, in the nacreous layer of Pinctada maxima. N66 is composed of carbonic anhydrase like and repeat domains, as described for nacrein (1) in the pearls of P. fucata. N14 is homologous to N16, recently found in the nacreous layer of P. fucata (2) and is characterized by high proportions of Gly, Tyr, and Asn together with NG repeat sequences. The molecular weights of these proteins were estimated as 59,814 and 13,734 Da, respectively. Structural differences were clearly indicated in the alignment and length of the repeat sequences of the sets of the homogeneous proteins (N66/nacrein and N14/N16). The longer repeat sequences of N66 and N14 may be responsible for P. maxima's excellent property of calcification. The in vitro crystallization experiments revealed that the mixture of N66 and N14 could induce platy aragonite layers highly similar to the nacreous layer, once adsorbed onto the membrane of the water insoluble matrix. Descriptors: oysters genetics, oysters metabolism, proteins genetics, proteins metabolism, base sequence, carbonic anhydrases chemistry, carbonic anhydrases genetics, carbonic anhydrases metabolism, cloning, molecular, crystallization, DNA, complementary genetics, molecular sequence data, molecular weight, proteins chemistry, repetitive sequences, amino acid, sequence homology, amino acid, chemistry, genetics, metabolism, complementary DNA, proteins, nacrein, carbonic anhydrases. Lees, D. (2000) Viruses and bivalve shellfish. Int J Food Microbiol 59(1 2): 81 116, ISSN: 0168 1605. NAL call no: QR115.I57 Abstract: The epidemiological data clearly demonstrates that filter feeding bivalve shellfish can, and do, act as efficient vehicles for the transmission of enteric viruses transmitted by the faecal oral route. This identified hazard has been documented as a cause for concern by various international agencies and has a long history. Disease outbreaks can occur on an epidemic scale as graphically illustrated by an outbreak of Hepatitis A in Shanghai, China in 1988 involving about 300,000 cases. Improvement of harvesting area water quality offers the most sustainable route to improvement in the virological quality of bivalve shellfish sold live. However there is growing awareness, and concern, that current regulatory standards based on faecal coliform monitoring do not fully protect the shellfish consumer from viral infection. New viral test methods based on PCR, and the development of alternative more reliable faecal pollution indicators, offer new approaches for the further development of public health controls. However, further work is required to build a scientific consensus and to understand the implications of their introduction into legislation. Descriptors: food microbiology standards, shellfish virology, viruses isolation and purification, Adenoviridae, Astrovirus, Caliciviridae, Enterovirus, Gastroenteritis epidemiology and virology, Great Britain, Hepatitis A epidemiology, Hepatitis A virology, Rotavirus. Marin, F.; Corstjens, P.; De Gaulejac, B.; De Vrind De Jong, E.; Westbroek, P. (2000) Mucins and molluscan calcification. Molecular characterization of mucoperlin, a novel mucin like protein from the nacreous shell molluscs.htm[3/31/2015 9:00:20 AM] "Information resources on the care and use of molluscs" layer of the fan mussel Pinna nobilis (Bivalvia, pteriomorphia). J Biol Chem 275(27): 20667 75, ISSN: 0021 9258. NAL call no: 381 J824 Abstract: A cDNA expression library constructed from mantle tissue mRNA of the Mediterranean fan mussel Pinna nobilis was screened with antibodies raised against the acetic acid soluble shell matrix of the same species. This resulted in the isolation of a 2138 base pair cDNA, containing 13 tandem repeats of 93 base pairs. The deduced protein has a molecular mass of 66.7 kDa and a isoelectric point of 4.8. This protein, which is enriched in serine and proline residues, was overexpressed, purified, and used for producing polyclonal antibodies. Immunological in situ and in vitro tests showed that the protein is localized in the nacreous aragonitic layer of P. nobilis, but not in the calcitic prisms. Because this protein of the nacre of P. nobilis exhibits some mucin like characteristics, we propose the name mucoperlin. This is the first paper reporting the cloning of a molluscan mucin and the first molecular evidence for the involvement of a mucin in molluscan calcification. This finding corroborates our previous hypothesis that some of the proteinaceous constituents of the molluscan shell matrix would derive from mucins, common to many metazoan lineages of the late Precambrian (Marin, F., Smith, M., Isa, Y., Muyzer, G. and Westbroek, P. (1996) Proc. Natl. Acad. Sci. U. S. A. 93, 1554 1559). The adaptation of an ancestral mucin to a new function, the regulation of the mineralization process, may be one of the molecular events, among others, that would explain the simultaneous emergence of organized calcification in many metazoan lineages during the Cambrian explosion. Descriptors: Mollusca genetics, mucins genetics, amino acid sequence, amino acids analysis, calcification, physiologic, calcium metabolism, calcium carbonate metabolism, calcium binding proteins chemistry, cloning, molecular, evolution, glycosylation, immunohistochemistry, Mediterranean Sea, molecular sequence data, Mollusca metabolism, mucins chemistry, recombinant proteins chemistry, sequence alignment, tandem repeat sequences. Martinez, G.; Olivares, A.Z.; Mettifogo, L. (2000) In vitro effects of monoamines and prostaglandins on meiosis reinitiation and oocyte release in Argopecten purpuratus Lamarck. Invertebrate Reproduction & Development, V. 38, N1 (OCT), P. 61-69, ISSN: 0168-8170. NAL call no: QP251.I628 Descriptors: Argopecten purpuratus, scallops, reproduction, spawning, meiosis, mussel, Dreissena polymorpha, zebra mussel, Patinopecten yessoensis, bivalve mollusks, reproductive process, arachidonic acid, serotonin, maturation, scallop, induction. McFadzen, I.; Eufemia, N.; Heath, C.; Epel, D.; Moore, M.; Lowe, D. (2000) Multidrug resistance in the embryos and larvae of the mussel Mytilus edulis. Mar Environ Res 50(1 5): 319 23, ISSN: 0141 1136. NAL call no: QH545.W3M36 Abstract: Cells exhibiting the multidrug resistance (MDR) phenotype demonstrate a decreased intracellular drug accumulation due to an active outward transport and decreased intracellular flux. This study demonstrates the inhibition of MDR in mussel (Mytilus edulis) embryos and larvae based on a simple bioassay. The development of embryos was assessed and abnormalities identified at key stages of development, including gastrulation, trochophore and prodissoconch stages. The incidence of developmental abnormalities was significantly increased in the presence of vinblastine, MMS, chloroquine, mitomycin C, cadmium chloride and colchicine, compared to clean seawater. Consistently, there was a further increase in the number and severity of deformities observed when each toxin was added in the presence of verapamil. Larval growth was also significantly impaired in the presence of verapamil. Increased accumulation of fluorescent MDR dyes, such as rhodamine B, has been measured and shown to be verapamil sensitive. This bioassay encompasses a period of intense cellular activity during which the impairment of a number of critical processes results in abnormal growth and development. Descriptors: mussels drug effects, mussels embryology, water pollutants, chemical toxicity, biological assay methods, biological assay veterinary, cadmium chloride toxicity, chloroquine toxicity, colchicine toxicity, drug resistance, multiple, drug synergism, larva drug effects, methyl methanesulfonate toxicity, mitomycin toxicity, phenotype, seawater, verapamil toxicity, vinblastine toxicity. Moura, G.; Vilarinho, L.; Machado, J. (2000) The action of Cd, Cu, Cr, Zn, and Pb on fluid composition of Anodonta cygnea (L.): organic components. Comp Biochem Physiol B Biochem Mol Biol 127(1): 105 12, ISSN: 1096 4959. NAL call no: QP501.C6 molluscs.htm[3/31/2015 9:00:20 AM] "Information resources on the care and use of molluscs" Abstract: The heavy metals, Cd, Cu, Cr, Zn, an