Neverita Didyma Research Articles

Taxonomy Of Naticidae Guilding, 1834 (Mollusca: Gastropoda) Collection From Sarawak Natural History Museum

This study focused on the taxonomic study of the gastropod family Naticidae based on specimens at the Sarawak Natural History Museum. A total of 146 specimens were investigated. There are 6 species found in the boxes of the specimen’s collection which are Mammilla melanostoma (Gmelin,1791), Neverita didyma (Röding,1798), Paratectonatica tigrina (Röding,1798), Polinices albumen (Linnaeus,1758), Polinices mammilla (Linnaeus,1758) and Tanea lineata (Röding,1798). A list of specimens of each species is provided in this study. From all the available specimens in the museum, a dichotomous key is formed. It is hoped that this study serves as a basis for further work on gastropods especially the family Naticidae in Sarawak.

Analytical Method Optimization of Tetrodotoxin and Its Contamination in Gastropods.

Tetrodotoxin (TTX) is an extremely potent marine biotoxin. An analytical method was developed for both trace contamination and extremely high levels of TTX in gastropods by liquid chromatography-tandem mass spectrometry (LC-MS/MS) with clean-up of cation exchange solid phase extraction (SPE) in this study. The limit of detection (LOD) in the sample matrix was 0.5 μg/kg. With the calibration of a screened internal standard (validamycin, IS), the linear range was 0.1-100 ng/mL (1.5-1500 μg/kg in sample matrix) with a correlation coefficient of r2 > 0.999. The average recoveries at three spiking levels (1.5 μg/kg, 44 μg/kg, and 1500 μg/kg) were 82.6-94.4% with relative standard deviations (RSDs) less than 8.4%. TTX levels in seven gastropods (741 samples) were studied. The contamination and analogues in Neverita didyma (N. didyma, 565 samples collected in Zhejiang province, China, from 2016 to 2022) were first reported. The detection rate of TTX in N. didyma was 34.2%. The average concentration was 23.1 μg/kg, and the maximum value was 2327 μg/kg. The time distribution study indicated that high contaminations of TTX occurred from May to August for N. didyma.

DNA Bar-Coding Based Identification of Neverita didyma (Roding 1798) and its Phylogeny

DNA Bar-Coding Based Identification of Neverita didyma (Roding 1798) and its Phylogeny

Study of Molluscs Diversity as Ecosystem Engineer from Beach of Sungai Bakau Village, Tanah Laut, South Kalimantan

Molluscs are engineered biota that play an important role in changing the structure and function of ecosystems, including coastal and mangroves. This study aims to record the diversity of molluscs as a group of engineers in coastal areas in Sungai Bakau Village, Tanah Laut, South Kalimantan. Purposive random sampling method was used to obtain mollusc data at three observation stations (Station 1 : sandy beaches, Station 2 : rocky beaches, and Station 3 : river estuaries). Only one type of bivalve was found (Meretirix meretrix) and 13 types of gastropods (Nassarius Sp., Turricula javana, Cerithidea alata, Polygona angulate, Distorsio decipiens, Latirus pictus, Bursa granularis, Latirus sp., Littorina undulate, Naticarius hebraeus, Murex. elenensis, Neverita didyma, and Turritella terebra). The highest diversity index (1.95) was found at station 1. While the evenness index is 0.755. Similarity index was 92.85% (stations 1-2 and stations 1-3) while at stations 2-3 was 85.71%. The highest density of Cerithidea alata is reached 2,996,700 ind/Ha and the least was Turritella terebra (20,000 ind/Ha). Water parameters between observation stations were close to each other : pH ± 7.6 - 7.7, temperature ± 29.3 - 29.7 0C, and salinity ± 34.9 - 35.4 ppt. The difference between research stations can be seen from sediment content. Station 1 has the highest sand content (96.2%). Station 2 consists of 64.7% sand dust and 20.6% clay. Station 3 has the highest dust content, reaching 84.6%. The types and presence of mollusks (bivalves and gastropods) at each research station is vary in value.

Food web biomagnification of the neurotoxin β-N-methylamino-L-alanine in a diatom-dominated marine ecosystem in China

The neurotoxin β-N-methylamino-L-alanine (BMAA) reported in some cyanobacteria and eukaryote microalgae is a cause of concern due to its potential risk of human neurodegenerative diseases. Here, BMAA distribution in phytoplankton, zooplankton, and other marine organisms was investigated in Jiaozhou Bay, China, a diatom-dominated marine ecosystem, during four seasons in 2019. Results showed that BMAA was biomagnified in the food web from phytoplankton to higher trophic levels. Trophic magnification factors (TMFs) for zooplankton, bivalve mollusks, carnivorous crustaceans and carnivorous gastropod mollusks were ca. 4.58, 30.1, 42.5, and 74.4, respectively. Putative identification of β-amino-N-methylalanine (BAMA), an isomer of BMAA, was frequently detected in phytoplankton samples. A total of 56 diatom strains of the genera Pseudo-nitzschia, Thalassiosira, Chaetoceros, Planktoniella, and Minidiscus isolated from the Chinese coast were cultured in the laboratory, among which 21 strains contained BMAA mainly in precipitated bound form at toxin concentrations ranging from 0.11 to 3.95 µg/g dry weight. Only 2,4-diaminobutyric acid (DAB) but not BMAA or BAMA was detected in seven species of bacteria isolated from the gut of gastropod Neverita didyma, suggesting that this benthic vector of BMAA may have accumulated this compound via trophic transfer.

Change of lipids in whelks (Neptunea arthritica cumingi Crosse and Neverita didyma) during cold storage

The objective of this study was to evaluate the change of lipids in two whelk samples during cold storage. Results showed that the peroxide value (PV) and thiobarbituric acid reactive substance (TBARS) increased while the percentage of polyunsaturated fatty acid decreased, indicating that lipid oxidation occurred. The cold storage significantly reduced the levels of triacylglycerol (TAG), polar lipid (PoL), phosphatidylcholine (PC) and phosphatidylethanolamine (PE) but increased the levels of acid value (AV), free fatty acid (FFA) and monoacylglycerol, suggesting the hydrolysis of lipids. Moreover, the results showed that the lipoxygenase, acid lipase and phospholipase contributed to the hydrolysis and oxidation of lipids in the two whelks. Additionally, partial least squares discriminant analysis showed PC was positively correlated with PE, PoL and TAG, but negatively correlated with AV, FFA, PV and TBARS, indicating there is a close relationship between hydrolysis and oxidation of lipids.

Characterization of the complete mitochondrial genome of Euspira gilva with phylogenetic analysis

Here, we determined the complete mitogenome sequence of Euspira gilva (Littorinimorpha: Naticidae). The complete mitochondrial genome is circular and 16,119 bp in length, containing 13 protein-coding genes (PCGs), 2 ribosomal RNA genes, and 22 transfer RNA genes. All PCGs and rRNA genes are encoded on the heavy strand while tRNA genes are distributed in both the strands. The overall nucleotides base composition of the heavy strand is A (31.80%), G (14.72%), C (13.72%), and T (39.76%), with an A + T bias (71.56%). All of the PCGs had ATG as their start codon. The common termination codon is TAA, except for nd4l terminated with TAG. The 22 tRNA genes could be folded into a typical clover-leaf secondary structure. As seen from the phylogenetic tree, E. gilva has a more close relationship with Neverita didyma and Glossaulax reiniana.

Comprehensive study of the lipid from whelk (Chlorostoma rusticum and Neverita didyma) with emphasis on characterization of phospholipid molecular species by shot-gun strategy

In the present study, an effective shot-gun lipidomic methodology was established to determine the glycerophospholipid (GP) molecular species of two species of edible marine whelks (Chlorostoma rusticum and Neverita didyma). Simultaneously, the lipid content, lipid classes, phospholipid (PL) subclasses and fatty acid compositions were also investigated. Over 210 molecular species of GP including glycerophosphocholine, lysoglycerophosphocholine, glycerophosphoethanolamine, lysoglycerophosphoethanolamine, glycerophosphoserine, lysoglycerophosphoserine, glycerophosphoinositol and lysoglycerophosphoinositol were characterized in the two abovementioned whelk species. The predominant GP molecular species contained n-3 long chain polyunsaturated fatty acid (n-3 LC-PUFA), especially docosahexaenoic acid and eicosapentaenoic acid. Meanwhile, PL (57.70-58.86% of total lipids) and PUFA (21.69-37.68% of total FA) take large proportions in whelk lipids. Among PL, phosphatidylcholine (50.58-52.41 mol%) and phosphatidylethanolamine (27.67-32.73 mol%) were dominant. Therefore, marine whelks turn out to be promising source of n-3 LC-PUFA existed in PL form and thus directly contribute to the health benefits of consumer.

Effects of hot air drying process on lipid quality of whelks Neptunea arthritica cumingi Crosse and Neverita didyma.

Whelks Neptunea arthritica cumingi Crosse and Neverita didyma were processed by hot air drying and changes of thei lipids and the mechanism involved were evaluated by analyzing peroxide value, thiobarbituric acid-reactive substances, total oxidation value, fatty acid composition, activities of lipases and lipoxygenase (LOX), as well as contents of triacylglycerol (TAG), free fatty acid (FFA), phosphatidylcholine (PC) and phosphatidylethanolamine (PE). The processing significantly decreased the contents of PC, PE and TAG but increased the content of FFA. The presence of acid lipase and phospholipase in whelk tissues and their activity preservation during processing suggest that the enzymes may help hydrolyze lipids. By contrast, the reduction of PC, PE and TAG was more pronounced than the increase in FFA in whelk tissues upon processing, indicating the oxidative degradation of FFA. LOX may play a role in lipid oxidation due to the stability of the starting components during processing.

The mitochondrial genome of the marine gastropod Neverita didyma (Roding, 1798) (Mollusca: Gastropoda)

In this study, the complete mitochondrial genome of the Neverita didyma (Mollusca: Gastropoda) was sequenced. The mitochondrial genome is 15,252 bp in length, containing 13 protein-coding genes, 2 ribosomal RNA genes, 22 transfer RNA genes. The overall nucleotides base composition of the heavy strand is 30.47% for A, 14.09%% for C, 15.89%for G, and 39.56% for T with an AT-rich feature (70.03%). All the protein-coding genes begin with an ATG codon, the common termination codon is TAA, except for nd2 and nd4l terminated with TAG and nd5 terminated by incomplete codon TA. Seen from the phylogenetic tree, Naticarius hebraeus, and N. didyma from the same Superfamily (Naticoidea) clustered into one branch. The data would provide useful data for further studies on population genetics and molecular systematics.

Cryptic genetic diversity of Neverita didyma in the coast of China revealed by phylogeographic analysis: implications for management and conservation

Revealing cryptic biodiversity and understanding the processes that promote lineage diversification will provide valuable insights into management and protection of exploitable species. Neverita didyma is one of the most common marine species along the coast of China and possesses highly economic and nutritional value. Despite being heavily harvested each year, the genetic diversity of this species has never been assessed in the coastal areas of China. Here, we analyzed the diversity of this species based on the barcode region of the mitochondrial gene Cytochrome Oxidase subunit I (COI) and utilized different species delineation approaches to infer evolutionarily significant units (ESUs). Three distinct ESUs, with high genetic distance among each, were identified. Divergence time estimates suggested that the high genetic distances were probably associated with historical isolation of the marginal seas during Pleistocene low sea level periods. The three ESUs did not map to distinct geographical distribution, possibly attributing to the repeated isolation in different refugia and random postglacial recolonization. Moreover, N. didyma in Haizhou Bay deserves priority protection due to its unique ESU. To improve management regulations in the marine realm, our research also stresses the need for more empirical studies on genetic diversity of commercially exploited species in coastal environments of China.

Distribution of uronic acid-containing polysaccharides in 5 species of shellfishes

Mollusks are a rich source of uronic acid-containing polysaccharides (UACPs) possessing biological and pharmacological activities. In the present study, UACP compositions of different tissues from 5 species of edible shellfishes, namely Neverita didyma, Natica janthostomoides, Saxidomus purpurata, Cyclina sinensis, and Chlamys farreri were systemically analyzed. Totally 10 UACPs were observed, including chondroitin sulfate, heparin, an identified mannoglucuronan, 3 unknown glycosaminoglycans (GAGs, U1, U3 and U6) with hexuronic acid-hexosamine repeating units, and 4 unknown non-GAGs (U2, U4, U5 and U7) with hexuronic acid-hexose repeating units. U4-7 showed tissue- and species-specificity while the other UACPs prevalently existed in these shellfish tissues. UACP compositions in tissues from the same shellfish species were similar for S. purpurata and C. sinensis but different for C. farreri, N. didyma and N. janthostomoides. And this investigation also indicates that the similarity of UACPs composition between different shellfishes is related to the genetic relationship.

New Typical Vector of Neurotoxin β-N-Methylamino-l-Alanine (BMAA) in the Marine Benthic Ecosystem.

The neurotoxin β-N-methylamino-l-alanine (BMAA) has been identified as an environmental factor triggering neurodegenerative diseases such as Amyotrophic Lateral Sclerosis (ALS) and Alzheimer’s disease (AD). We investigated the possible vectors of BMAA and its isomers 2,4-diaminobutyric acid (DAB) and N-2(aminoethyl)glycine (AEG) in marine mollusks collected from the Chinese coast. Sixty-eight samples of marine mollusks were collected along the Chinese coast in 2016, and were analyzed by an HILIC-MS/MS (hydrophilic interaction liquid chromatography with tandem quadrupole mass spectrometer) method without derivatization. BMAA was detected in a total of five samples from three species: Neverita didyma, Solen strictus, and Mytilus coruscus. The top three concentrations of free-form BMAA (0.99~3.97 μg·g−1 wet weight) were detected in N. didyma. DAB was universally detected in most of the mollusk samples (53/68) with no species-specific or regional differences (0.051~2.65 μg·g−1 wet weight). No AEG was detected in any mollusk samples tested here. The results indicate that the gastropod N. didyma might be an important vector of the neurotoxin BMAA in the Chinese marine ecosystem. The neurotoxin DAB was universally present in marine bivalve and gastropod mollusks. Since N. didyma is consumed by humans, we suggest that the origin and risk of BMAA and DAB toxins in the marine ecosystem should be further investigated in the future.

Isolation and characterization of 20 microsatellite loci in Neverita didyma (Röding 1798)

Neverita didyma is a commercially important and over-exploited species. In order to investigate its genetic diversity and population structure, 20 polymorphic microsatellite loci were isolated and characterized. The number of alleles per locus ranged from 2 to 20, and the observed and expected heterozygosities varied from 0.276 to 1.000 and from 0.331 to 0.939, respectively. These microsatellites will be a useful tool for fisheries management and conservation programme for this species.

Selection of Bioindicators of Polybrominated Diphenyl Ethers, Polychlorinated Biphenyls, and Organochlorine Pesticides in Mollusks in the Chinese Bohai Sea

Mollusks, including bivalve and gastropod samples, were collected in the summer of 2006 and 2007 to evaluate the spatial patterns of organochlorine pesticides (OCPs), polychlorinated biphenyl (PCBs), and polybrominated biphenyl ethers (PBDEs) in the coastal water of the Chinese Bohai Sea. Seven species of mollusks, including Rapana venosa (Rap), Neverita didyma (Nev), Scapharca subcrenata (Sca), Mytilus edulis (Blue mussel, Myt), Amusium (Amu), Meretix meretrix (Mer), and Crassostrea talienwhanensis (Oyster, Ost) were investigated to select appropriate bioindicators. Compared with other species, Ost and Myt possess higher lipid contents and have higher concentrations of OCPs and PBDEs. Multivariate linear regression analysis revealed that the most influential factor on the contaminant concentrations in mollusks is the trophic level (TL), followed by the lipid contents. Concentrations of OCPs, PCBs, and PBDEs correlated negatively with the TL of the selected mollusks. Results of principal component and correlation analyses suggest that Ost and Myt can be used as potential bioindicators of pollution by OCPs, PCBs, and PBDEs of the Chinese Bohai Sea.

Investigation of organochlorine pesticides (OCPs) in mollusks collected from coastal sites along the Chinese Bohai Sea from 2002 to 2004

Mollusks living in seas can accumulate organochlorine pesticides (OCPs). The residue levels of selected OCPs: dichlorodiphenyltrichloroethane ( p,p′-DDT, o,p′-DDT, p,p′-DDE, p,p′-DDD), hexachlorocyclohexanes (α-, β-, γ- and δ-HCH) in gastropod and bivalve species collected from ten coastal cites along the Chinese Bohai Sea were investigated from 2002 to 2004. The species included nine kinds of mollusks: Rapana venosa, Neverita didyma, Scapharca subcrenata, Mytilus edulis, Amusium, Crassostrea talienwhanensis, Meretix meretrix, Sinonovacula constricta, Ruditapes philippinarum, Mactra veneriformis. The results showed that OCPs widely existed in the mollusks organisms. p,p′-DDT, p,p′-DDE, β-HCH were the major compounds. Statistical analysis (One-way ANOVA) showed that the contents of OCPs in these mollusks did not change obviously from 2002 to 2004. Principal component analysis (PCA) was also used for determining the polluting characters existing in this selected field.

Neverita delessertiana (Récluz in Chenu, 1843): a naticid species (Gastropoda: Caenogastropoda) distinct from Neverita duplicata (Say, 1822) based on molecular data, morphological characters, and geographical distribution

The members of the caenogastropod family Naticidae show highly conserved morphological characters, which in many cases complicate species separation. In such cases DNA sequence analysis may help to distinguish between species. In this work partial sequences from the small mitochondrial ribosomal RNA (16S rRNA) gene, the small nuclear ribosomal RNA (18S rRNA) gene, a short intron of the nuclear calmodulin (Cal) gene, and the mitochondrial cytochrome oxidase subunit I (COI) gene are shown to differ significantly between the genomes of what generally had been considered to be merely two morphological variants of the common Western Atlantic naticid Neverita duplicata (Say, 1822). Sequence differences between the two forms of Neverita duplicata are similar to differences between either of these two forms and the Eastern Pacific Neverita reclusiana (Deshayes, 1839), the Indopacific Neverita didyma (Röding, 1798), and the Mediterranean Neverita josephinia (Risso, 1826). The COI sequences divergence between the two forms of Neverita duplicata is in the range of the average COI sequences divergence reported for congeneric species of Mollusca (Hebert 2003). We conclude that in addition to Neverita duplicata a second shallow water species of Neverita exists along the US Atlantic and Gulf coasts for which the name Neverita delessertiana (Récluz, 1843) is available.

Neverita delessertiana (Récluz in Chenu, 1843): a naticid species (Gastropoda: Caenogastropoda) distinct from Neverita duplicata (Say, 1822) based on molecular data, morphological characters, and geographical distribution

The members of the caenogastropod family Naticidae show highly conserved morphological characters, which in many cases complicate species separation. In such cases DNA sequence analysis may help to distinguish between species. In this work partial sequences from the small mitochondrial ribosomal RNA (16S rRNA) gene, the small nuclear ribosomal RNA (18S rRNA) gene, a short intron of the nuclear calmodulin (Cal) gene, and the mitochondrial cytochrome oxidase subunit I (COI) gene are shown to differ significantly between the genomes of what generally had been considered to be merely two morphological variants of the common Western Atlantic naticid Neverita duplicata (Say, 1822). Sequence differences between the two forms of Neverita duplicata are similar to differences between either of these two forms and the Eastern Pacific Neverita reclusiana (Deshayes, 1839), the Indopacific Neverita didyma (Roding, 1798), and the Mediterranean Neverita josephinia (Risso, 1826). The COI sequences divergence between the two forms of Neverita duplicata is in the range of the average COI sequences divergence reported for congeneric species of Mollusca (Hebert 2003). We conclude that in addition to Neverita duplicata a second shallow water species of Neverita exists along the US Atlantic and Gulf coasts for which the name Neverita delessertiana (Recluz, 1843) is available.

Contamination of shellfish from Shanghai seafood markets with paralytic shellfish poisoning and diarrhetic shellfish poisoning toxins determined by mouse bioassay and HPLC

This paper reports the results of investigations of shellfish toxin contamination of products obtained from Shanghai seafood markets. From May to October 2003, 66 samples were collected from several major seafood markets. Paralytic shellfish poisoning (PSP) and diarrhetic shellfish poisoning (DSP) toxins in shellfish samples were monitored primarily by a mouse bioassay, then analysed by HPLC for the chemical contents of the toxins. According to the mouse bioassay, eight samples were detected to be contaminated by PSP toxins and seven samples were contaminated by DSP toxins. Subsequent HPLC analysis indicated that the concentrations of the PSP toxins ranged from 0.2 to 1.9 µg/100 g tissues and the main components were gonyautoxins 2/3 (GTX2/3). As for DSP, okadaic acid was detected in three samples, and its concentration ranged from 3.2 to 17.5 µg/100 g tissues. Beside okadaic acid, its analogues, dinophysistoxins (DTX1), were found in one sample. According to the results, gastropod (Neverita didyma) and scallop (Argopecten irradians) were more likely contaminated with PSP and DSP toxins, and most of the contaminated samples were collected from Tongchuan and Fuxi markets. In addition, the contaminated samples were always found in May, June and July. Therefore, consumers should be cautious about eating the potential toxic shellfish during this specific period.

Study on the contamination of heavy metals and their correlations in mollusks collected from coastal sites along the Chinese Bohai Sea

Mollusks living in seas can accumulate heavy metals, and may serve as excellent passive biomonitors. During a period of 1 year, bioaccumulation of As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Se, and Zn was examined in nine kinds of mollusks ( Rapana venosa, Neverita didyma, Scapharca subcrenata, Mytilus edulis, Amusium, Crassostrea talienwhanensis, Meretix meretrix, Ruditapes philippinarum, and Mactra veneriformis), which were collected at eight coastal sites along the Chinese Bohai Sea. Metal concentrations were directly determined by inductively coupled plasma mass spectrometer (ICP-MS). Two certified reference materials, dogfish muscle (DORM-2) and mussel (GBW 08571), were used to validate the methods, and the recoveries were within 83.72–112.30% of the certified values. Bioaccumulation of metals varied strongly among sampling sites and species. Statistical analysis (one-way ANOVA) indicated that different species examined showed different bioaccumulation of metals, and perhaps they could be used as potential biomonitors to investigate the contamination levels of heavy metals. Principal component analysis (PCA) and correlation analysis were used to study the relationships between these heavy metals. The results showed that, in nine mollusks' tissues, there are significant correlations between these elements in adjacent main group or subgroup in periodic table of elements.