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To address the structure–activity relationship of Chlamys farreri polysaccharides on their immunostimulatory efficacy, two polysaccharides (CFP-1 and CFP-2) were extracted from Chlamys farreri by hot water extraction, and separated through column chromatography. The isolated CFPs were chemically analyzed to clarify their physicochemical characteristics and cultured with murine macrophage RAW264.7 cells, in order to evaluate their immunostimulatory efficacy. Despite the fact that both CFP-1 and CFP-2 were mainly comprised of glucose lacking the triple-helix structure, as revealed through preliminary physicochemical analyses, obvious differences in regard to molecular weight (Mw), glucuronic acid content (GAc) and branching degree (BD) were observed between CFP-1 and CFP-2. In in vitro immunostimulatory assays for macrophage RAW264.7 cells, it was demonstrated that CFP-2 with larger Mw, more GAc and BD could evidently promote phagocytosis and increase the production of NO, IL-6, TNF-α and IL-1β secretion, by activating the expression of iNOS, IL-6, TNF-α and IL-1β genes, respectively. Hence, CFP-2 shows great promise as a potential immunostimulatory agent in the functional foods and nutraceutical industry, while CFP-1, with lower molecular weight, less GAc and BD, displays its weaker immunostimulatory efficacy, based on the indistinctive immunostimulatory parameters of CFP-1.

BACKGROUND: Acute viral necrosis virus (AVNV) is the causative agent of a serious disease resulting in high mortality in cultured Chinese scallops, Chlamys farreri. We have sequenced and analyzed the complete genome of AVNV. RESULTS: The AVNV genome is a linear, double-stranded DNA molecule of 210,993 bp with a nucleotide composition of 38.5% G + C. A total of 123 open reading frames were predicted to encode functional proteins, ranging from 41 to 1,878 amino acid residues. The DNA sequence of AVNV is 97% identical to that of ostreid herpesvirus 1 (OsHV-1), and the amino acid sequences of the encoded proteins of these two viruses are 94-100% identical. The genomic organization of AVNV is similar to that of OsHV-1, and consists of two unique regions (170.4 kb and 3.4 kb, respectively), each flanked by two inverted repeats (7.6 kb and 10.2 kb, respectively), with a third unique region (1.5 kb) situated between the two internal repeats. CONCLUSIONS: Our results indicate that AVNV is a variant of OsHV-1. The AVNV genome sequence provides information useful for understanding the evolution and divergence of OsHV-1 in marine molluscs.

Bivalve mollusks exhibit hermaphroditism and sex reversal/differentiation. Studies generally focus on transcriptional profiling and specific genes related to sex determination and differentiation. Few studies on sex reversal/differentiation have been reported. A combination analysis of gonad proteomics and transcriptomics was conducted on Chlamys nobilis to provide a systematic understanding of sex reversal/differentiation in bivalves. We obtained 4258 unique peptides and 93,731 unigenes with good correlation between messenger RNA and protein levels. Candidate genes in sex reversal/differentiation were found: 15 genes differentially expressed between sexes were identified and 12 had obvious sexual functions. Three novel genes (foxl2, β-catenin, and sry) were expressed highly in intersex individuals and were likely involved in the control of gonadal sex in C. nobilis. High expression of foxl2 or β-catenin may inhibit sry and activate 5-HT receptor and vitellogenin to maintain female development. High expression of sry may inhibit foxl2 and β-catenin and activate dmrt2, fem-1, sfp2, sa6, Amy-1, APCP4, and PLK to maintain male function. High expression of sry, foxl2, and β-catenin in C. nobilis may be involved in promoting and maintaining sex reversal/differentiation. The downstream regulator may not be dimorphic expressed genes, but genes expressed in intersex individuals, males and females. Different expression patterns of sex-related genes and gonadal histological characteristics suggested that C. nobilis may change its sex from male to female. These findings suggest highly conserved sex reversal/differentiation with diverged regulatory pathways during C. nobilis evolution. This study provides valuable genetic resources for understanding sex reversal/differentiation (intersex) mechanisms and pathways underlying bivalve reproductive regulation.

beta -catenin is a key signaling molecule in the canonical Wnt pathway, which is involved in animal development. However, little information has been reported for beta -catenin in bivalves. In the present study, we cloned a homolog of beta -catenin from the scallop Chlamys farreri and determined its expression characteristics. The full-length cDNA of beta -catenin was 3,353 bp, including a 2,511 bp open reading frame that encoded a predicted 836 amino acid protein. Level of the beta -catenin mRNA increased significantly (P<0.05) with C. farreri gonadal development and presented a sexually dimorphic expression pattern in the gonads, which was significantly high in ovaries detected by quantitative real-time polymerase chain reaction (qRT-PCR). Immunohistochemical analysis revealed that the beta -catenin was mainly located in germ cells of the gonads, with obvious positive immune signals in the oogonia and oocytes of ovaries as well as in the spermatogonia and spermatocytes of testes, implying beta -catenin might be involved in the gametogenesis of C. farreri. Furthermore, when 0.1 mu g/mL and 0.2 mu g/mL DKK-1 (an inhibitor of the canonical Wnt pathway) were added in vitro to culture medium containing testis cells of C. farreri, the expression of beta -catenin decreased significantly detected by qRT-PCR (P<0.05), suggesting the canonical Wnt signal pathway exists in the scallop testis. Similarly, when 50 mu M and 100 mu M quercetin (an inhibitor of beta -catenin) were added in vitro to the culture system, Dax1 expression was significantly down-regulated compared with controls (P<0.05), implying the beta -catenin is an upstream gene of Dax1 and is involved in the regulation of C. farreri spermatogenesis.

Long-chain polyunsaturated fatty acids (LC-PUFAs) are essential in lots of important physiological processes, while, many marine species have no or limited ability of endogenous PUFA biosynthesis, normally due to the lack of key enzymes such as fatty acid desaturase (FAD). In this study, we isolated a scallop Chlamys nobilis cDNA with high homology to vertebrate FADs. Functional characterization in recombinant yeast Saccharomyces cerevisiae showed that scallop FAD exhibited Delta 5-desaturation activity towards both saturated and PUFA substrates. Thus, it efficiently desaturated exogenously added PUFA C20:4(n - 3) and C20:3(n - 6) to C20:5(n - 3) (EPA) and C20:4(n - 6) (ARA) respectively. It also converted the yeast's endogenous C18:0 into C18:1(n - 13), and participated in the biosynthesis of non-methylene-interrupted FA by introducing a double bond to C20:3(n - 3) and C20:2(n - 6) in the Delta 5 carbon. Temporal transcript profile of scallop FAD was studied during early embryonic development. High level of mRNA was found at the beginning of embryogenesis (egg) and noticeable decreases of were observed during larvae development, suggesting maternal FAD mRNA transfer to the embryo. Further, FAD transcripts were detected in all tissues analyzed, with the gonad and hepatopancreas showing the highest expression.

More than 4700 nominal family-group names (including names for fossils and ichnotaxa) are nomenclaturally available in the order Coleoptera. Since each family-group name is based on the concept of its type genus, we argue that the stability of names used for the classification of beetles depends on accurate nomenclatural data for each type genus. Following a review of taxonomic literature, with a focus on works that potentially contain type species designations, we provide a synthesis of nomenclatural data associated with the type genus of each nomenclaturally available family-group name in Coleoptera. For each type genus the author(s), year of publication, and page number are given as well as its current status (i.e., whether treated as valid or not) and current classification. Information about the type species of each type genus and the type species fixation (i.e., fixed originally or subsequently, and if subsequently, by whom) is also given. The original spelling of the family-group name that is based on each type genus is included, with its author(s), year, and stem. We append a list of nomenclaturally available family-group names presented in a classification scheme. Because of the importance of the Principle of Priority in zoological nomenclature, we provide information on the date of publication of the references cited in this work, when known. Several nomenclatural issues emerged during the course of this work. We therefore appeal to the community of coleopterists to submit applications to the International Commission on Zoological Nomenclature (henceforth “Commission”) in order to permanently resolve some of the problems outlined here. The following changes of authorship for type genera are implemented here (these changes do not affect the concept of each type genus): CHRYSOMELIDAE: Fulcidax Crotch, 1870 (previously credited to “Clavareau, 1913”); CICINDELIDAE: Euprosopus W.S. MacLeay, 1825 (previously credited to “Dejean, 1825”); COCCINELLIDAE: Alesia Reiche, 1848 (previously credited to “Mulsant, 1850”); CURCULIONIDAE: Arachnopus Boisduval, 1835 (previously credited to “Guérin-Méneville, 1838”); ELATERIDAE: Thylacosternus Gemminger, 1869 (previously credited to “Bonvouloir, 1871”); EUCNEMIDAE: Arrhipis Gemminger, 1869 (previously credited to “Bonvouloir, 1871”), Mesogenus Gemminger, 1869 (previously credited to “Bonvouloir, 1871”); LUCANIDAE: Sinodendron Hellwig, 1791 (previously credited to “Hellwig, 1792”); PASSALIDAE: Neleides Harold, 1868 (previously credited to “Kaup, 1869”), Neleus Harold, 1868 (previously credited to “Kaup, 1869”), Pertinax Harold, 1868 (previously credited to “Kaup, 1869”), Petrejus Harold, 1868 (previously credited to “Kaup, 1869”), Undulifer Harold, 1868 (previously credited to “Kaup, 1869”), Vatinius Harold, 1868 (previously credited to “Kaup, 1869”); PTINIDAE: Mezium Leach, 1819 (previously credited to “Curtis, 1828”); PYROCHROIDAE: Agnathus Germar, 1818 (previously credited to “Germar, 1825”); SCARABAEIDAE: Eucranium Dejean, 1833 (previously “Brullé, 1838”). The following changes of type species were implemented following the discovery of older type species fixations (these changes do not pose a threat to nomenclatural stability): BOLBOCERATIDAE: Bolbocerus bocchus Erichson, 1841 for Bolbelasmus Boucomont, 1911 (previously Bolboceras gallicum Mulsant, 1842); BUPRESTIDAE: Stigmodera guerinii Hope, 1843 for Neocuris Saunders, 1868 (previously Anthaxia fortnumi Hope, 1846), Stigmodera peroni Laporte & Gory, 1837 for Curis Laporte & Gory, 1837 (previously Buprestis caloptera Boisduval, 1835); CARABIDAE: Carabus elatus Fabricius, 1801 for Molops Bonelli, 1810 (previously Carabus terricola Herbst, 1784 sensu Fabricius, 1792); CERAMBYCIDAE: Prionus palmatus Fabricius, 1792 for Macrotoma Audinet-Serville, 1832 (previously Prionus serripes Fabricius, 1781); CHRYSOMELIDAE: Donacia equiseti Fabricius, 1798 for Haemonia Dejean, 1821 (previously Donacia zosterae Fabricius, 1801), Eumolpus ruber Latreille, 1807 for Euryope Dalman, 1824 (previously Cryptocephalus rubrifrons Fabricius, 1787), Galeruca affinis Paykull, 1799 for Psylliodes Latreille, 1829 (previously Chrysomela chrysocephala Linnaeus, 1758); COCCINELLIDAE: Dermestes rufus Herbst, 1783 for Coccidula Kugelann, 1798 (previously Chrysomela scutellata Herbst, 1783); CRYPTOPHAGIDAE: Ips caricis G.-A. Olivier, 1790 for Telmatophilus Heer, 1841 (previously Cryptophagus typhae Fallén, 1802), Silpha evanescens Marsham, 1802 for Atomaria Stephens, 1829 (previously Dermestes nigripennis Paykull, 1798); CURCULIONIDAE: Bostrichus cinereus Herbst, 1794 for Crypturgus Erichson, 1836 (previously Bostrichus pusillus Gyllenhal, 1813); DERMESTIDAE: Dermestes trifasciatus Fabricius, 1787 for Attagenus Latreille, 1802 (previously Dermestes pellio Linnaeus, 1758); ELATERIDAE: Elater sulcatus Fabricius, 1777 for Chalcolepidius Eschscholtz, 1829 (previously Chalcolepidius zonatus Eschscholtz, 1829); ENDOMYCHIDAE: Endomychus rufitarsis Chevrolat, 1835 for Epipocus Chevrolat, 1836 (previously Endomychus tibialis Guérin-Méneville, 1834); EROTYLIDAE: Ips humeralis Fabricius, 1787 for Dacne Latreille, 1797 (previously Dermestes bipustulatus Thunberg, 1781); EUCNEMIDAE: Fornax austrocaledonicus Perroud & Montrouzier, 1865 for Mesogenus Gemminger, 1869 (previously Mesogenus mellyi Bonvouloir, 1871); GLAPHYRIDAE: Melolontha serratulae Fabricius, 1792 for Glaphyrus Latreille, 1802 (previously Scarabaeus maurus Linnaeus, 1758); HISTERIDAE: Hister striatus Forster, 1771 for Onthophilus Leach, 1817 (previously Hister sulcatus Moll, 1784); LAMPYRIDAE: Ototreta fornicata E. Olivier, 1900 for Ototreta E. Olivier, 1900 (previously Ototreta weyersi E. Olivier, 1900); LUCANIDAE: Lucanus cancroides Fabricius, 1787 for Lissotes Westwood, 1855 (previously Lissotes menalcas Westwood, 1855); MELANDRYIDAE: Nothus clavipes G.-A. Olivier, 1812 for Nothus G.-A. Olivier, 1812 (previously Nothus praeustus G.-A. Olivier, 1812); MELYRIDAE: Lagria ater Fabricius, 1787 for Enicopus Stephens, 1830 (previously Dermestes hirtus Linnaeus, 1767); NITIDULIDAE: Sphaeridium luteum Fabricius, 1787 for Cychramus Kugelann, 1794 (previously Strongylus quadripunctatus Herbst, 1792); OEDEMERIDAE: Helops laevis Fabricius, 1787 for Ditylus Fischer, 1817 (previously Ditylus helopioides Fischer, 1817 [sic]); PHALACRIDAE: Sphaeridium aeneum Fabricius, 1792 for Olibrus Erichson, 1845 (previously Sphaeridium bicolor Fabricius, 1792); RHIPICERIDAE: Sandalus niger Knoch, 1801 for Sandalus Knoch, 1801 (previously Sandalus petrophya Knoch, 1801); SCARABAEIDAE: Cetonia clathrata G.-A. Olivier, 1792 for Inca Lepeletier & Audinet-Serville, 1828 (previously Cetonia ynca Weber, 1801); Gnathocera vitticollis W. Kirby, 1825 for Gnathocera W. Kirby, 1825 (previously Gnathocera immaculata W. Kirby, 1825); Melolontha villosula Illiger, 1803 for Chasmatopterus Dejean, 1821 (previously Melolontha hirtula Illiger, 1803); STAPHYLINIDAE: Staphylinus politus Linnaeus, 1758 for Philonthus Stephens, 1829 (previously Staphylinus splendens Fabricius, 1792); ZOPHERIDAE: Hispa mutica Linnaeus, 1767 for Orthocerus Latreille, 1797 (previously Tenebrio hirticornis DeGeer, 1775). The discovery of type species fixations that are older than those currently accepted pose a threat to nomenclatural stability (an application to the Commission is necessary to address each problem): CANTHARIDAE: Malthinus Latreille, 1805, Malthodes Kiesenwetter, 1852; CARABIDAE: Bradycellus Erichson, 1837, Chlaenius Bonelli, 1810, Harpalus Latreille, 1802, Lebia Latreille, 1802, Pheropsophus Solier, 1834, Trechus Clairville, 1806; CERAMBYCIDAE: Callichroma Latreille, 1816, Callidium Fabricius, 1775, Cerasphorus Audinet-Serville, 1834, Dorcadion Dalman, 1817, Leptura Linnaeus, 1758, Mesosa Latreille, 1829, Plectromerus Haldeman, 1847; CHRYSOMELIDAE: Amblycerus Thunberg, 1815, Chaetocnema Stephens, 1831, Chlamys Knoch, 1801, Monomacra Chevrolat, 1836, Phratora Chevrolat, 1836, Stylosomus Suffrian, 1847; COLONIDAE: Colon Herbst, 1797; CURCULIONIDAE: Cryphalus Erichson, 1836, Lepyrus Germar, 1817; ELATERIDAE: Adelocera Latreille, 1829, Beliophorus Eschscholtz, 1829; ENDOMYCHIDAE: Amphisternus Germar, 1843, Dapsa Latreille, 1829; GLAPHYRIDAE: Anthypna Eschscholtz, 1818; HISTERIDAE: Hololepta Paykull, 1811, Trypanaeus Eschscholtz, 1829; LEIODIDAE: Anisotoma Panzer, 1796, Camiarus Sharp, 1878, Choleva Latreille, 1797; LYCIDAE: Calopteron Laporte, 1838, Dictyoptera Latreille, 1829; MELOIDAE: Epicauta Dejean, 1834; NITIDULIDAE: Strongylus Herbst, 1792; SCARABAEIDAE: Anisoplia Schönherr, 1817, Anticheira Eschscholtz, 1818, Cyclocephala Dejean, 1821, Glycyphana Burmeister, 1842, Omaloplia Schönherr, 1817, Oniticellus Dejean, 1821, Parachilia Burmeister, 1842, Xylotrupes Hope, 1837; STAPHYLINIDAE: Batrisus Aubé, 1833, Phloeonomus Heer, 1840, Silpha Linnaeus, 1758; TENEBRIONIDAE: Bolitophagus Illiger, 1798, Mycetochara Guérin-Méneville, 1827. Type species are fixed for the following nominal genera: ANTHRIBIDAE: Decataphanes gracilis Labram & Imhoff, 1840 for Decataphanes Labram & Imhoff, 1840; CARABIDAE: Feronia erratica Dejean, 1828 for Loxandrus J.L. LeConte, 1853; CERAMBYCIDAE: Tmesisternus oblongus Boisduval, 1835 for Icthyosoma Boisduval, 1835; CHRYSOMELIDAE: Brachydactyla annulipes Pic, 1913 for Pseudocrioceris Pic, 1916, Cassida viridis Linnaeus, 1758 for Evaspistes Gistel, 1856, Ocnoscelis cyanoptera Erichson, 1847 for Ocnoscelis Erichson, 1847, Promecotheca petelii Guérin-Méneville, 1840 for Promecotheca Guérin- Méneville, 1840; CLERIDAE: Attelabus mollis Linnaeus, 1758 for Dendroplanetes Gistel, 1856; CORYLOPHIDAE: Corylophus marginicollis J.L. LeConte, 1852 for Corylophodes A. Matthews, 1885; CURCULIONIDAE: Hoplorhinus melanocephalus Chevrolat, 1878 for Hoplorhinus Chevrolat, 1878; Sonnetius binarius Casey, 1922 for Sonnetius Casey, 1922; ELATERIDAE: Pyrophorus melanoxanthus Candèze, 1865 for Alampes Champion, 1896; PHYCOSECIDAE: Phycosecis litoralis P

Bivalves comprise 30,000 extant species, constituting the second largest group of mollusks. However, limited genetic research has focused on this group of animals so far, which is, in part, due to the lack of genomic resources. The advent of high-throughput sequencing technologies enables generation of genomic resources in a short time and at a minimal cost, and therefore provides a turning point for bivalve research. In the present study, we performed de novo transcriptome sequencing to first produce a comprehensive expressed sequence tag (EST) dataset for the Yesso scallop (Patinopecten yessoensis). In a single 454 sequencing run, 805,330 reads were produced and then assembled into 32,590 contigs, with about six-fold sequencing coverage. A total of 25,237 unique protein-coding genes were identified from a variety of developmental stages and adult tissues based on sequence similarities with known proteins. As determined by GO annotation and KEGG pathway mapping, functional annotation of the unigenes recovered diverse biological functions and processes. Transcripts putatively involved in growth, reproduction and stress/immune-response were identified. More than 49,000 single nucleotide polymorphisms (SNPs) and 2,700 simple sequence repeats (SSRs) were also detected. Our data provide the most comprehensive transcriptomic resource currently available for P. yessoensis. Candidate genes potentially involved in growth, reproduction, and stress/immunity-response were identified, and are worthy of further investigation. A large number of SNPs and SSRs were also identified and ready for marker development. This resource should lay an important foundation for future genetic or genomic studies on this species.

Background Bivalves represent a vital economic resource in aquaculture for their high productivity and extensive market demand. Growth is one of the most important and desired aquaculture traits for bivalves, regulated by multiple levels, notably intricate metabolic processes. However, the understanding of the metabolic profiles that influence bivalve growth is limited, particularly from a multi-tissue perspective. Results In this study, metabolic profiles of multiple tissues of Chlamys farreri with different growth performance were systematically investigated by ultraperformance liquid chromatography quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS). Through comparing the metabolic variation between fast-growing (FG) scallops and slow-growing (SG) scallops, 613, 509, 105, and 192 significantly different metabolites (SDMs) were identified in the mantle, gill, adductor muscle, and digestive gland, respectively. Growth-related metabolic pathways including sphingolipid metabolism, fatty acid biosynthesis, and ABC transporter pathway, along with 11 SDMs associated with growth traits were identified in all four tissues, implying they were involved in the growth of multiple tissues in scallops. Tissue-specific metabolic profiling indicated that sulfur-containing amino acid metabolism in the mantle potentially contributed to shell growth, while the gill synergistically participated with the mantle through various metabolic processes, such as tyrosine metabolism, glycine, serine, and threonine metabolism and melanogenesis; energy metabolism was crucial for adductor muscle growth; and nutrients digestion and absorption in the digestive gland were linked to scallop growth. Conclusions Our results represent the first comprehensive analysis of the crucial pathways and metabolites associated with the growth of C. farreri , offering valuable insights for future bivalve aquaculture production.

Background The noble scallop Chlamys nobilis Reeve displays polymorphism in shell and muscle colors. Previous research showed that the orange scallops with orange shell and muscle had a significantly higher carotenoid content than the brown ones with brown shell and white muscle. There is currently a need to identify candidate genes associated with carotenoid-based coloration. Results In the present study, 454 GS-FLX sequencing of noble scallop transcriptome yielded 1,181,060 clean sequence reads, which were assembled into 49,717 isotigs, leaving 110,158 reads as the singletons. Of the 159,875 unique sequences, 11.84% isotigs and 9.35% singletons were annotated. Moreover, 3,844 SSRs and over 120,000 high confidence variants (SNPs and INDELs) were identified. Especially, one class B scavenge receptor termed SRB-like-3 was discovered to express only in orange scallops and absent in brown ones, suggesting a significant association with high carotenoid content. Down-regulation of SRB-like-3 mRNA by RNA interference remarkably decreased blood carotenoid, providing compelling evidence that SRB-like-3 is an ideal candidate gene controlling carotenoid deposition and determining orange coloration. Conclusion Transcriptome analysis of noble scallop reveals a novel scavenger receptor significantly associated with orange scallop rich in carotenoid content. Our findings pave the way for further functional elucidation of this gene and molecular basis of carotenoid deposition in orange scallop.

Marine bivalves could accumulate paralytic shellfish toxins (PSTs) produced by toxic microalgae, which might induce oxidative stress. Glutathione peroxidases (GPxs) are key enzymes functioning in the antioxidant defense, whereas our understanding of their roles in PST challenge in bivalves is limited. Herein, through genome-wide screening, we identified nine (CfGPx) and eight (PyGPx) GPx genes in Zhikong scallop (Chlamys farreri) and Yesso scallop (Patinopecten yessoensis), respectively, and revealed the expansion of GPx3 sub-family in both species. RNA-Seq analysis revealed high expression of scallop GPx3s after D stage larva during early development, and in adult hepatopancreas. However, in scallops exposed to PST-producing dinoflagellates, no GPx was significantly induced in the hepatopancreas. In scallop kidneys where PSTs were transformed to higher toxic analogs, most CfGPxs were up-regulated, with CfGPx3s being acutely and chronically induced by Alexandrium minutum and A. catenella exposure, respectively, but only one PyGPx from GPx3 subfamily was up-regulated by A. catenella exposure. Our results suggest the function of scallop GPxs in protecting kidneys against the oxidative stresses by PST accumulation or transformation. The tissue-, species-, and toxin-dependent expression pattern of scallop GPxs also implied their functional diversity in response to toxin exposure.