Family Conidae Research Articles

A perspective on toxicology of Conus venom peptides.

The evolutionarily unique and ecologically diverse family Conidae presents fundamental opportunities for marine pharmacology research and drug discovery. The focus of this investigation is to summarize the worldwide distribution of Conus and their species diversity with special reference to the Indian coast. In addition, this study will contribute to understanding the structural properties of conotoxin and therapeutic application of Conus venom peptides. Cone snails can inject a mix of various conotoxins and these venoms are their major weapon for prey capture, and may also have other biological purposes, and some of these conotoxins fatal to humans. Conus venoms contain a remarkable diversity of pharmacologically active small peptides; their targets are an iron channel and receptors in the neuromuscular system. Interspecific divergence is pronounced in venom peptide genes, which is generally attributed to their species specific biotic interactions. There is a notable interspecific divergence observed in venom peptide genes, which can be justified as of biotic interactions that stipulate species peculiar habitat and ecology of cone snails. There are several conopeptides used in clinical trials and one peptide (Ziconotide) has received FDA approval for treatment of pain. This perspective provides a comprehensive overview of the distribution of cone shells and focus on the molecular approach in documenting their taxonomy and diversity with special reference to geographic distribution of Indian cone snails, structure and properties of conopeptide and their pharmacological targets and future directions.

Effects of geographical heterogeneity in species interactions on the evolution of venom genes.

Geographical heterogeneity in the composition of biotic interactions can create a mosaic of selection regimes that may drive the differentiation of phenotypes that operate at the interface of these interactions. Nonetheless, little is known about effects of these geographical mosaics on the evolution of genes encoding traits associated with species interactions. Predatory marine snails of the family Conidae use venom, a cocktail of conotoxins, to capture prey. We characterized patterns of geographical variation at five conotoxin genes of a vermivorous species, Conus ebraeus, at Hawaii, Guam and American Samoa, and evaluated how these patterns of variation are associated with geographical heterogeneity in prey utilization. All populations show distinct patterns of prey utilization. Three 'highly polymorphic' conotoxin genes showed significant geographical differences in allelic frequency, and appear to be affected by different modes of selection among populations. Two genes exhibited low levels of diversity and a general lack of differentiation among populations. Levels of diversity of 'highly polymorphic' genes exhibit a positive relationship with dietary breadth. The different patterns of evolution exhibited by conotoxin genes suggest that these genes play different roles in prey capture, and that some genes are more greatly affected by differences in predator-prey interactions than others. Moreover, differences in dietary breadth appear to have a greater influence on the differentiation of venoms than differences in the species of prey.

One, four or 100 genera? A new classification of the cone snails.

We present a new classification for the genus Conus sensu lato (family Conidae), based on molecular phylogenetic analyses of 329 species. This classification departs from both the traditional classification in only one genus and from a recently proposed shell- and radula-based classification scheme that separates members of this group into five families and 115 genera. Roughly 140 genus-group names are available for Recent cone snails. We propose to place all cone snails within a single family (Conidae) containing four genera—Conus, Conasprella, Profundiconus and Californiconus (with Conus alone encompassing about 85% of known species)—based on the clear separation of cone snails into four distinct and well-supported groups/lineages in molecular phylogenetic analyses. Within Conus and Conasprella, we recognize 57 and 11 subgenera, respectively, that represent well-supported subgroupings within these genera, which we interpret as evidence of intrageneric distinctiveness. We allocate the 803 Recent species of Conidae listed as valid in the World Register of Marine Species into these four genera and 71 subgenera, with an estimate of the confidence for placement of species in these taxonomic categories based on whether molecular or radula and/or shell data were used in these determinations. Our proposed classification effectively departs from previous schemes by (1) limiting the number of accepted genera, (2) retaining the majority of species within the genus Conus and (3) assigning members of these genera to species groups/subgenera to enable the effective communication of these groups, all of which we hope will encourage acceptance of this scheme.

The First Record of a Marriage Cone, Conus sponsalis (Conidae: Gastropoda) from Korea

The Conus Linnaeus, 1758 is a large genus of marine gastropod mollusks belonging to the family Conidae. The Conus species are mostly distributed in the tropical waters of the world, and they are especially abundant in the Indo-West Pacific region. To date, more than 600 species, most of which are predatory species, have been named worldwide in this genus and only six species have been recorded in the Korean waters. Conus sponsalis Hwass in Brugui<TEX>$\grave{e}$</TEX>re, 1792 was collected from Jeju Island and identified as a new Korean record. In this study, we report a description of the shell morphology of the species.

A species-rich molluscan assemblage in a coralligenous bottom of the Alboran Sea (south-western Mediterranean): intra-annual changes and ecological considerations

The composition and structure of a molluscan assemblage inhabiting an outcrop with a coralligenous community was studied in southern Spain. A total of 117 molluscan species were identified, with gastropods as the dominant group.Calyptraea chinensiswas the dominant species and the family Conidae presented the highest number of species. The Shannon–Wiener diversity index and the Evenness showed non-significant changes between cold and warm months, displaying high values (~4 bits and ~0.8 bits respectively). Some of the dominant and/or frequent species are strictly associated with coralligenous-building organisms, such asNeosimnia speltawith gorgonians. Regarding trophic guilds, carnivores are the dominant group, followed by filter feeders due to the high abundance ofC. chinensis. Regarding biogeographical distributions, most of these species (&lt;95%) are widely distributed in European waters, the number of strictly Mediterranean species being very low. The Alboran Sea represents the distributional limit towards the Mediterranean for some species found in this bottom, such as the AtlanticBela powisiana. Rocky–coralligenous bottoms are scarce in the western Alboran Sea but support a high species richness molluscan assemblage, displaying higher diversity values than the surrounding soft bottoms and increasing the biodiversity at local scale. This high biodiversity is partly explained by the coexistence of different taxa with contrasting biogeographical affinities promoted by the geographical location of the area. Due to this, conservation efforts should be required to protect this stretch of coastline where one of the most biodiverse invertebrate assemblages along the European coasts can be found.

Genetic divergence and geographic variation in the deep-water Conus orbignyi complex (Mollusca: Conoidea).

Puillandre, N. et al. (2010) Genetic divergence and geographic variation in a deep-water cone lineage: molecular and morphological analyses of the Conus orbignyi complex (Mollusca: Conoidea).The cone snails (family Conidae) are a hyperdiverse lineage of venomous gastropods. Two standard markers, COI and ITS2, were used to define six genetically-divergent groups within a subclade of Conidae that includes Conus orbignyi; each of these was then evaluated based on their shell morphology. We conclude that three forms, previously regarded as subspecies of Conus orbignyi are distinct species, now recognized as Conus orbignyi, Conus elokismenos and Conus coriolisi. In addition, three additional species (Conus pseudorbignyi, Conus joliveti and Conus comatosa) belong to this clade. Some of the proposed species (e.g., Conus elokismenos) are possibly in turn complexes comprising multiple species. Groups such as Conidae illustrate the challenges generally faced in species delimitation in biodiverse lineages. In the case of the Conus orbignyi complex, not only are there definable, genetically divergent lineages, but also considerable geographic variation within each group. Our study suggests that an intensive analysis of multiple specimens within a single locality helps to minimize the confounding effects of geographic variation and can be a useful starting point for circumscribing different species within such a confusing complex.

New raphitomine gastropods (Gastropoda: Conidae: Raphitominae) from the South-West Pacific

Based on material stored in Museum National d'Histoire Naturelle (MNHN) eight new species collected from bathyal depths in South West Pacific archipelagos ( Solomon Islands and Fiji) are described. The new species belong to the rather poorly known genera Acanthodaphne Bonfitto et Morassi, 2006, Acamptodaphne Shuto, 1971, Buccinaria Kittl, 1887, Cryptodaphne Powell, 1942 and Mioawateria Vella, 1954 all belonging to subfamily Raphitominae Bellardi, 1875 in the family Conidae Fleming, 1822. Acamptodaphne eridmata sp. nov. has a broad distribution being reported from the Solomon Islands and Taiwan. Finding of the new species here discussed in South West Pacific archipelagos provides a significant extension to the previously known geographical range of these raphitomine genera.

Some Neuropharmacological Effects of the Crude Venom Extract of &lt;i&gt;Conus musicus&lt;/i&gt; in Mice

This study reports some neuropharmacological effects of the crude venom extract of Conus musicus (family Conidae) in mice using various experimental models. The crude venom was found to significantly increase tail flick reaction time in mice. The effects of the venom on the central nervous system were studied by observing spontaneous motor activity, gross behaviour, rota-rod performance and potentiation of pentobarbitone sleeping time in mice. Preliminary acute toxicity evaluation was also carried out and the LD50 was found to be 460.23 &#956;g/kg following intraperitoneal administration. At a dose of 200 &#956;g/kg i.p., the extract produced a reduction in spontaneous motor activity, altered gross behavior and motor coordination and prolonged pentobarbitone-sleeping time. A liquid chromatography mass spectroscopic study has indicated the presence of &#969;-conotoxin in the crude venom extract. Keywords: Conus musicus, sedation, spontaneous motor activity, gross behavior, motor coordination East and Central African Journal of Pharmaceutical Sciences Vol. 10 (2) 2007: pp. 27-33

Some Neuropharamacological Effects of the Crude Extract of Conus parvatus in Mice

The present study was aimed to characterize the type of conotoxin present in Conus parvatus. (CP) belongs to family conidae, through neuro-pharmacological activities of the crude venom extract on some of the CNS animal experiment using mice as animal model. The effects of CP on CNS were studied, by using spontaneous motor activity, gross behavior, rota-rod performance, analgesic activity and potentiation of pentobarbitone sleeping time in mice. Preliminary evaluation of acute toxicity was also carried out; The LD50 value was found to be 425.20 mcg kg(-1) by i.p. route. The extract (200 mcg kg(-1) i.p.) was found to produce, reduction in spontaneous motor activity, potent analgesic activity, reduction in motor coordination and prolonged pentobarbitone-sleeping time. From the above all pharmacological activities, it may concluded that, the conotoxin present in CP is most likely to be a alpha-conotoxin and also it will be more suitable to continue the studies in the areas of analgesic and other CNS depressant therapeutic areas after isolation of the pure cono-peptide from CP.

Typhlosyrinx -like tropical deep-water turriform gastropods (Mollusca, Gastropoda, Conoidea)

Based on radular and protoconch morphology, the genus Typhlosyrinx Thiele, 1925 has been successively classified in the subfamily Turriculinae of the family Turridae and in the subfamily Clathurellinae of the family Conidae. It is shown that the protoconch had earlier been misinterpreted, and the presence of a diagonally cancellated sculpture indicates a placement in the conid subfamily Raphitominae. Two conchologically similar genera, based on teleoconch sculpture and radular morphology are recognized: Typhlosyrinx, with axial ribbing on teleoconch spire whorls and a radula with long (250 μm) barbed teeth, and Leiosyrinx n. gen., without axial sculpture and a radula with short (<100 μm) simplified teeth. Five species (two new) of Typhlosyrinx and four species (all new) of Leiosyrinx are recognized, all at bathyal depths between 280 and 1840 m in the tropical Indo-Pacific and Panamic provinces. The two genera are not known earlier than the Pliocene, where they already occurred in deep-water assemblages.

Rediscovery of the Antarctic species Sipho gaini Lamy, 1910 (Gastropoda: Neogastropoda) with remarks on its taxonomic position

Examination of the holotype of Sipho gaini Lamy, 1910, attributed by recent authors to the genus Chlanidota (Buccinulidae), revealed that this species belongs to the genus Belaturricula and is a senior synonym of Belaturricula antarctica Dell, 1990. A redescription of the shell, anterior alimentary system, and radular morphology of Belaturricula gaini is provided. The genus Belaturricula is transferred to the family Conidae (sensu Taylor et al. 1993) on the basis of its radula, which is composed of hollow marginal teeth. The presence of a large shell, prominent operculum, acinous salivary glands, radular teeth with narrow bases in B. gaini, as well as the absence of buccal lips and rhyncodeal introvert, all indicate affinities with the conid subfamily Clathurellinae. Because the radula of Pontiothauma ergata Hedley (1916) is nearly indistinguishable from that of Belaturricula gaini, we reassign Hedley's species to the genus Belaturricula as Belaturricula ergata (Hedley, 1916).

5α,8α‐Epidioxycholest‐6‐en‐3‐β‐ol from three cone snails of the Indian ocean

AbstractThree cone snail species (Conus ebraeus, C. leopardus, C. tessulatus, family Conidae) have been investigated for their sterolic fraction. Besides cholesterol, 5α,8α‐epidioxycholest‐6‐en‐3‐β‐ol has been isolated from each species and the structure determined using two‐dimensional nuclear magnetic resonance. The occurrence of 5α,8α‐epidioxycholest‐6‐en‐3‐β‐ol in high amounts in the crude extract (0.5%), constitutes an interesting source of this compound.