Abalone Haliotis Discus Hannai Research Articles

Greenlip Abalone (Haliotis laevigata) Genome and Protein Analysis Provides Insights into Maturation and Spawning.

Wild abalone (Family Haliotidae) populations have been severely affected by commercial fishing, poaching, anthropogenic pollution, environment and climate changes. These issues have stimulated an increase in aquaculture production; however production growth has been slow due to a lack of genetic knowledge and resources. We have sequenced a draft genome for the commercially important temperate Australian ‘greenlip’ abalone (Haliotis laevigata, Donovan 1808) and generated 11 tissue transcriptomes from a female adult abalone. Phylogenetic analysis of the greenlip abalone with reference to the Pacific abalone (Haliotis discus hannai) indicates that these abalone species diverged approximately 71 million years ago. This study presents an in-depth analysis into the features of reproductive dysfunction, where we provide the putative biochemical messenger components (neuropeptides) that may regulate reproduction including gonad maturation and spawning. Indeed, we isolate the egg-laying hormone neuropeptide and under trial conditions induce spawning at 80% efficiency. Altogether, we provide a solid platform for further studies aimed at stimulating advances in abalone aquaculture production. The H. laevigata genome and resources are made available to the public on the abalone ‘omics website, http://abalonedb.org.

Genetic determination of sex and shell color in the Pacific abalone Haliotis discus hannai revealed by an integrated linkage map.

Integrated linkage maps for each sex have been constructed for the Pacific abalone Haliotis discus hannai using three F1 mapping families based on co-dominant markers. A total of 273 markers were placed on the female map, spanning 927.3cM with an average interval of 3.64cM, whereas 277 markers were mapped on the male map, covering 727.0cM with an average spacing of 2.80cM. Both female and male maps consisted of 18 linkage groups, corresponding well with the number of chromosomes. Furthermore, the sex-determining locus and the green/orange shell color controlling locus were mapped to the linkage group 3 (LG3) and LG9 respectively. A marker completely linked to phenotypic sex was identified, and the sex determination system was further concluded as paternal heterogametic (males XY and females XX). Based on the segregation ratio of the shell color in the progeny, a simple recessive model of epistasis was proposed to explain the distribution of different color morphs (green, orange and blue): the recessive allele determining orange type masks the effect of the locus controlling green and blue types, whereas the dominant allele at the green/orange locus permits the expression of green and blue types controlled by another locus. The current consensus map provides a useful framework for genetic studies in the Pacific abalone. Mapping of the sex-determining locus and the shell color-controlling locus leads to further understanding of the mechanisms underlying these important traits.

Mannan oligosaccharide increases the growth performance, immunity and resistance capability against Vibro Parahemolyticus in juvenile abalone Haliotis discus hannai Ino

This trial was conducted to investigate the effect of mannose oligosaccharides (MOS) on the growth performance, antioxidation, immunity and disease resistance of Vibro Parahemolyticus in juvenile abalone Haliotis discus hannai Ino. Four formulated diets were produced to contain 0.00 g/kg, 0.40 g/kg, 0.80 g/kg and 1.60 g/kg Actigen®, with functional ingredients of MOS, respectively. Accordingly, the experimental diets were named as A0, A4, A8 and A16. After 120-days feeding trial, the best growth performance was observed in A8 group (P < 0.05) and there was no significant difference in A0, A4 and A16 groups. With the increase of dietary MOS, the activity of the total antioxidant capacity in hepatopancreas is increasingly elevated (P < 0.05) while no significant difference was observed on activity of glutathione S‐transferase (P > 0.05). The activities of superoxide dismutase and glutathione peroxidase were firstly increased and then decreased, with the highest values in A8 group (P < 0.05). Immune-related parameters were significantly affected by dietary MOS inclusion. Specifically, the activities of alkaline phosphatase and acid phosphatase in hepatopancreas and serum of abalone fed diets containing MOS were significantly higher than those of control A0 group (P < 0.05). Moreover, the highest values of both enzymes were observed in hepatopancreas of A8 group but in serum of A16 group, respectively. The lysozyme activities in hepatopancreas and serum of A4 group were significantly higher than those of other groups (P < 0.05) and there was no significant difference in A0, A8 and A16 groups (P > 0.05). The activities of cytophagy and respiratory burst in serum of abalone were not significantly affected by dietary MOS content (P > 0.05). The mRNA levels of focal adhesion kinase and integrin-linked kinase were gradually elevated with the increase of dietary MOS, with the highest value recorded in A16 group (P < 0.05). The gene expression of caspse-3 in A8 group was dramatically higher than those of other groups (P < 0.05) and there was no significant difference in A0, A4 and A16 groups (P > 0.05). The mRNA level of nuclear factor-κB was not significantly affected by dietary MOS (P > 0.05). During 56 h of V. Parahemolyticus challenge period, the accumulated mortality rate of abalone fed diets containing MOS were significantly lower than that of control A0 group in each time point (P < 0.05). Overall, the lowest rate was happened in A8 group (P < 0.05). In conclusion, MOS inclusion in diet has obviously positive effect on growth, immunity and disease resistance capability of abalone, with the optimal level of Actigen® at 0.80 g/kg in diet.

Study on Tolerance and Immune Response of Pacific Abalone Haliotis discus hannai during Simulated Air Exposure of Live Transportation

Pacific abalone (Haliotis discus hannai) is an economically important species of sea snails found in China. Live abalones sold in domestic markets are sealed in insulated containers for transportation over extended periods of time (6–24 h), during which this species may experience stressful conditions and spoil. This study assessed the survival rate and weight loss rate (WLR) of abalone under various treatments to determine the optimal packaging transport conditions. Specifically, temperature, supplemental humidity and oxygen, and air exposure during simulated live transport were investigated. Results revealed that the survival rate increased significantly after cold-water shock and humidity control, whereas oxygen supplements did not have a significant effect. In addition, WLR significantly increased over time (P < 0.05). An additional experiment was conducted to investigate the stress response caused by air exposure. Hemocyte parameters, including total hemocyte count (THC), hemocyte mortality, and reactive oxygen species (ROS), were estimated for 2, 6, 12, 24, and 30 h after air exposure at different temperatures. Results revealed that THC significantly decreased after 30 h of air exposure at 5 and 10°C, and after 24 h of air exposure at 20°C. Hemocyte mortality and ROS significantly increased, peaking after 30 h at 5 and 10°C, followed by a gradual decrease over the subsequent 24 h recovery period. THC and ROS levels remained higher than the control levels by the end of the recovery period. The parameters investigated in this study could serve as indicators for the effects on the functional immune response and physiological stress of abalone during live transportation.

Scanning Electron Micrographs of the Early Life Stages of the Pacific Abalone Haliotis discus hannai (INO, 1953)

The Pacific abalone Haliotis discus hannai is a valuable food resource in China. Understanding the early development of this species will allow cell fate tracking and may help to guide artificial seeding. Scanning electron microscopy (SEM) was used to examine the morphologies of the major life stages of H. discus hannai from artificial fertilization to the juvenile stage (23 days postfertilization). The results represented the first comprehensive SEM micrograph record of early development in the Haliotidae. Special attention was also paid to shell formation in H. discus hannai, as these results might help inform biomineral-related research.

Physiological Response of Pacific Abalone (Haliotis discus hannai) Hepatopancreas to Heat Stress

Pacific abalone Haliotis discus hannai is one of the most economically important marine shellfish and is mainly distributed in the cooler seas of northern China. The molecular reactions that occur in this species under high temperature conditions have not been determined. To understand the molecular mechanisms of this species under heat stress, transcriptomic analysis of the hepatopancreas was performed at 33°C (22°C was used for the control) for 1 h on an Illumina HiSeq 2500 platform (pooling of six animals into single RNA-sequencing libraries). The results showed that 17,852 unigenes were annotated. In all, 8,532 genes were significantly differentially expressed in the test group compared with the control group, including 4,788 upregulated and 3,744 downregulated genes. Enrichment analysis identified some noteworthy GO terms (cellular process and response to stimulus) and pathways (protein processing in the endoplasmic reticulum (ER) and apoptotic signaling pathways), and these were further analyzed. Analysis showed that genes indicative of mitochondrial damage were upregulated; DNA damage formation, and fatty acid and amino acid synthesis increased; fatty acid decomposition reduced; and misfolded proteins accumulated in the ER, and the unfolded protein response and ER-associated degradation were triggered to relieve ER stress. In addition, the apoptotic pathway was activated; however, some genes associated with anti-apoptosis and molecular chaperones were upregulated to maintain homeostasis after heat stress. These data provide an increased understanding of the heat stress mechanisms in Pacific abalone.

Boiled Abalone Byproduct Peptide Exhibits Anti-Tumor Activity in HT1080 Cells and HUVECs by Suppressing the Metastasis and Angiogenesis in Vitro.

Abalone (Haliotis discus hannai) is a precious seafood in the market. It has been reported that biological active substances derived from abalone have anti-oxidative, anti-inflammatory, anti-bacterial, and anti-thrombosis potential. However, there were few studies to assess whether they have anti-cancer potential. In this study, we evaluated the anti-metastasis and anti-pro-angiogenic factors and mechanism of action of boiled abalone byproduct peptide (BABP, EMDEAQDPSEW) in human fibrosarcoma (HT1080) cells and human umbilical vein endothelial cells (HUVECs). The results demonstrated that BABP treatment significantly lowers migration and the invasion of HT1080 cells and HUVECs. BABP inhibits phorbol 12-myristate 13-acetate (PMA)-induced matrix metalloproteinase (MMP) expression and activity by blocking mitogen-activated protein kinases (MAPKs) and NF-κB signaling and hypoxia-induced vascular endothelial growth factor (VEGF) secretion and hypoxia inducible factor (HIF)-1α accumulation through suppressing the AKT/mTOR signal pathway. BABP treatment inhibits VEGF-induced VEGFR-2 expression and tube formation in HUVECs. The effect of BABP on anti-metastatic and anti-vascular activity in HT1080 cells and HUVECs revealed that BABP may be a potential pharmacophore for tumor therapy in the future.

Improving productivity management of commercial abalone Haliotis diversicolor supertexta and Haliotis discus hannai aquaculture in Taiwan: A bioeconomic analysis

The aquaculture techniques and operating management of production processes can influence the production performance of the overall aquaculture fishery. This study collected biological and economic data through of questionnaires from the production process of Taiwan's abalone culture industry and used the principles of economics and multivariate statistics to analyze the key for the profits of Taiwan's abalone industry. The results showed that the stocking density, production scale, and culture mode influenced the inputs and outputs of the abalone industry. Large-scale polyculture of Haliotis diversicolor supertexta and Haliotis discus hannai had the best profitability. Therefore, farmers who only culture Haliotis diversicolor supertexta are suggested to use polyculture model and moderately increase the stocking density to increase the economic benefit of cultures.

Physiological responses of the abalone Haliotis discus hannai to daily and seasonal temperature variations

Organisms inhabiting tidal mixing-front zones in shallow temperate seas are subjected to large semidiurnal temperature fluctuations in summer. The ability to optimize energy acquisition to this episodic thermal oscillation may determine the survival, growth and development of these ectotherms. We compared the physiological and molecular responses of Haliotis discus hannai cultivated in suspended cages to fluctuating or stable temperature conditions. Several physiological indicators (respiration, excretion rates and O:N) were measured in both conditions, and alterations in the proteome during thermal fluctuations were assessed. No summer mortality was observed in abalone cultivated in fluctuating temperatures compared with that at stable high temperatures. Metabolic rates increased sharply during stable warm summer conditions and fluctuated in accordance with short-term temperature fluctuations (20–26 °C). Ammonia excretion rates during acute responses were comparable in both conditions. When abalone were exposed to fluctuating temperatures, enzyme activities were downregulated and structure-related protein expression was upregulated compared with that at an acclimation temperature (26 °C), highlighting that exposure to low temperatures during fluctuations alters molecular processes. Our results reveal that modulation of physiological traits and protein expression during semidiurnal thermal fluctuations may buffer abalone from the lethal consequences of extreme temperatures in summer.

A Novel Peptide from Abalone (Haliotis discus hannai) to Suppress Metastasis and Vasculogenic Mimicry of Tumor Cells and Enhance Anti-Tumor Effect In Vitro.

Vasculogenic mimicry (VM) formed by tumor cells plays a vital role in the progress of tumor, because it provides nutrition for tumor cells and takes away the metabolites. Therefore, the inhibition of VM is crucial to the clinical treatment of tumors. In this study, we investigated the anti-tumor effect of a novel peptide, KVEPQDPSEW (AATP), isolated from abalone (Haliotis discus hannai) on HT1080 cells by migration, invasion analysis and the mode of action. The results showed that AATP effectively inhibited MMPs by blocking MAPKs and NF-κB pathways, leading to the downregulation of metastasis of tumor cells. Moreover, AATP significantly inhibited VM and pro-angiogenic factors, including VEGF and MMPs by suppression of AKT/mTOR signaling. In addition, molecular docking was used to study the interaction of AATP and HIF-1α, and the results showed that AATP was combined with an active site of HIF-1α by a hydrogen bond. The effect of AATP on anti-metastatic and anti-vascular in HT1080 cells revealed that AATP may be a potential lead compound for treatment of tumors in the future.

Remineralization and preservation of sedimentary organic carbon, and authigenic mineral formation in Alian Bay and its adjacent areas, China: Implication for the influence of abalone (Haliotis discus hannai Ino) and kelp (Saccharina japonica) mariculture

Although mariculture activities play a significant role in coastal carbon cycling, there is a lack of research on sedimentary organic carbon (SOC) in mariculture areas.In this study, remineralization of SOC in Ailian Bay, China, and an adjacent offshore control area was analyzed by combining sediment and pore water analyses, to investigate the effects of mariculture on the preservation of SOC and the related mechanisms. The significant higher total organic carbon (TOC) to sediment surface area in abalone culture area (0.74 ± 0.10 mg·m−2) than those in control area (0.59 ± 0.06 mg·m−2) suggested the maricultural activities may increase the preservation efficiency of SOC. During anaerobic incubations, higher vertical profiles and production rates of ΣCO2 in pore water of sediments in the abalone culture area than those in the control area indicated that maricultural activities may increase the rate of organic carbon remineralization. Furthermore, similar findings in dissolved organic carbon (DOC) suggested maricultural activities may increase the release of DOC in the sedimentary environment, which is an important supplement to the marine DOC pool. Additionally, the higher vertical concentrations and fluxes of the three major cations (i.e., K+, Ca2+, and Mg2+) coupled with the increased rate of SOC remineralization in the abalone culture area demonstrated that the maricultural activities strongly strengthened the formation of authigenic mineral. In conclusion, these findings suggested that maricultural activities play an important role in the coastal carbon cycle, significantly affecting the remineralization, preservation of SOC and the biogeochemical cycling of other important biogenic elements.

Neural Ganglia Transcriptome and Peptidome Associated with Sexual Maturation in Female Pacific Abalone (Haliotis discus hannai).

Genetic information of reproduction and growth is essential for sustainable molluscan fisheries and aquaculture management. However, there is limited knowledge regarding the reproductive activity of the commercially important Pacific abalone Haliotis discus hannai. We performed de novo transcriptome sequencing of the ganglia in sexually immature and mature female Pacific abalone to better understand the sexual maturation process and the underlying molecular mechanisms. Of the ~305 million high-quality clean reads, 76,684 transcripts were de novo-assembled with an average length of 741 bp, 28.54% of which were annotated and classified according to Gene Ontology terms. There were 256 differentially expressed genes between the immature and mature abalone. Tandem mass spectrometry analysis, as compared to the predicted-peptide database of abalone ganglia transcriptome unigenes, identified 42 neuropeptide precursors, including 29 validated by peptidomic analyses. Label-free quantification revealed differential occurrences of 18 neuropeptide families between immature and mature abalone, including achatin, FMRFamide, crustacean cardioactive peptide, and pedal peptide A and B that were significantly more frequent at the mature stage. These results represent the first significant contribution to both maturation-related transcriptomic and peptidomic resources of the Pacific abalone ganglia and provide insight into the roles of various neuropeptides in reproductive regulation in marine gastropods.

Effects of abalone (Haliotis discus hannai Ino) and kelp (Saccharina japonica) mariculture on sources, distribution, and preservation of sedimentary organic carbon in Ailian Bay, China: Identified by coupling stable isotopes (δ13C and δ15N) with C/N ratio analyses

To investigate the effects of mariculture on the sources, distribution and preservation of sedimentary organic carbon (SOC), sediments from an mariculture area in Ailian Bay, China, and a control area were analyzed for grain size composition, total organic carbon (TOC), total nitrogen (TN), carbon/nitrogen (C/N) ratio, and stable carbon and nitrogen isotopic composition (δ13C and δ15N). The sedimentary type of sediments in study area was clay silt. TOC, TN, C/N, δ13C, and δ15N ranged from 0.58 to 1.21%, 0.06–0.17%, 6.29–9.82, −23.20 to −18.50‰, and 6.17–7.38‰, respectively, and followed similar spatial patterns. TOC, TN and δ13C were higher in mariculture area than in control area. Biodeposit and kelp OC contributions greater of SOC in mariculture area than the control area (biodeposits: 20.10 ± 4.84 to 6.2 ± 1.3%; kelp: 15.3 ± 6.63 to 5.2 ± 0.84%). Overall, mariculture activities significantly influence the sources, distribution and preservation of SOC.

Molecular characterization, expression analysis, and functional properties of multiple 5-hydroxytryptamine receptors in Pacific abalone (Haliotis discus hannai)

Neurotransmitters such as serotonin (5-hydroxytryptamine; 5-HT) in the central nervous system regulate diverse physiological functions, including reproduction, feeding, learning, and memory, in diverse animal phyla. 5-HT and the 5-HT1 subtype receptor play important roles in sexual maturation and in the initiation of gamete release in mollusks. However, little is known about the involvement of other 5-HT receptor subfamilies in the reproduction process. In the present study, we identified the cDNAs encoding eight subtypes of 5-HT receptors from the ganglia tissues of the Pacific abalone Haliotis discus hannai (Mollusca; Gastropoda; Haliotidae), and examined the gonadal expression of the transcripts of 5-HT receptors. A phylogenetic analysis indicated that the molluskan 5-HT receptors are largely classified into four major clades: 5-HT1/5/7, 5-HT2, 5-HT4, and 5-HT6. Among the H. discus hannai (Hdh) 5-HT1-7 transcripts, Hdh5-HT1B, 4A, 4B, and 6 were the major subtypes detected in the mature ovary. Estradiol-17β injection into the pedal sinus induced the downregulation of 5-HT4B and upregulation of 5-HT6 transcripts in the ovary of mature abalone within 72 h. In HEK293 cells overexpressing Hdh5-HT1B, forskolin-stimulated cAMP response element luciferase (CRE-Luc) reporter activity was inhibited by 5-HT in a dose-dependent manner, whereas serum response element luciferase (SRE-Luc) activity was not affected. In Hdh5-HT4A-expressing HEK293 cells, forskolin-stimulated CRE-Luc and SRE-Luc reporter activities were both marginally increased by treatment with a high dose of 5-HT. Our results provide new insights into the roles of 5-HT through diverse G protein-coupled 5-HT receptors in the reproductive process of mollusks.

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Reproductive success of released hatchery stocks in the Pacific abalone Haliotis discus hannai

There has been grave concern in stock enhancement programs regarding the effects of stocking practices on resource augmentation of ensuing generations through reproduction of released hatchery stocks. Evaluation of whether released seedlings successfully produce offspring in the natural environment is a first step toward a better understanding of such inter-generation stocking effects. Against this background, we examined the reproductive success of released hatchery stocks of a Pacific abalone species, Haliotis discus hannai, on the basis of microsatellite-based parentage analysis. Adults of hatchery-raised abalone were released from 2014 to 2016 into the Toyoura area of Funka Bay (Hokkaido Island, Japan), where natural gene flow from other habitats was expected to rarely occur. After the reproductive season of H. discus hannai in Funka Bay in 2016, we collected 2016-year-class wild-born juveniles from Toyoura and determined parentages between the juveniles and released individuals. The results of this analysis revealed that approximately 10% of the juveniles were descended from the released hatchery stocks.

Different Transcriptomic Responses to Thermal Stress in Heat-Tolerant and Heat-Sensitive Pacific Abalones Indicated by Cardiac Performance.

The Pacific abalone Haliotis discus hannai is one of the most economically important mollusks in China. Even though it has been farmed in southern China for almost 20 years, summer mortality remains the most challengeable problem for Pacific abalone aquaculture recently. Here, we determined the different heat tolerance ability for five selective lines of H. discus hannai by measuring the cardiac performance and Arrhenius breakpoint temperature (ABT). The Red line (RL) and Yangxia line (YL) were determined as the most heat-sensitive and most heat-tolerant line, respectively. Heart rates for RL were significantly lower than those of the YL at the same temperature (p < 0.05). The differentially expressed genes (DEGs), which were enriched in several pathways including cardiac muscle contraction, glutathione metabolism and oxidative phosphorylation, were identified between RL and YL at control temperature (20°C) and heat stress temperature (28.5°C, the ABT of the RL) by RNA-seq method. In the RL, 3370 DEGs were identified between the control and the heat-stress temperature, while only 1351 DEGs were identified in YL between these two temperature tests. Most of these DEGs were enriched in the pathways such as protein processing in endoplasmic reticulum, nucleotide binding and oligomerization domain (NOD) like receptor signaling, and ubiquitin mediated proteolysis. Notably, the most heat-tolerant line YL used an effective heat-protection strategy based on moderate transcriptional changes and regulation on the expression of key genes.

Protection of dietary selenium-enriched seaweed Gracilaria lemaneiformis against cadmium toxicity to abalone Haliotis discus hannai

Seaweed Gracilaria lemaneiformis is the main dietary source of the abalone mariculture industry in China. In this study, we examined the protection of selenium (Se)-enriched G. lemaneiformis against cadmium (Cd) toxicity in the abalone, Haliotis discus hannai, using various indices including metal concentration (Se and Cd), growth rate, GPx enzymatic antioxidants, and metallothionein (MT) concentration over a period of 28 days of exposure. The growth rates and Se contents increased significantly in abalones fed with Se-enriched G. lemaneiformis, while the toxicity of Cd was reduced. Seven to 12 days Cd exposure to the Se-enriched G. lemaneiformis not only affected GPx activity but the MT levels fluctuated irregularly. MT concentrations increased after 3 days exposure and then gradually decreased to the control level after Day 7. There were statistically significant positive correlations between MT levels, GPx activity and Se concentrations, and negative relationships between MT levels, GPx activity and Cd levels in abalones. These findings suggest that Se-enriched Gracilaria protects abalone against Cd toxicity. The possible mechanism is the induction of MT with a concomitant increased capacity of GPx enzymatic antioxidants.

Characterization of the complete mitochondrial genome of Pacific abalone Haliotis discus hannai

The complete mitochondrial genome of Pacific abalone Haliotis discus hannai, an economically valuable shellfish in China, was sequenced and analyzed. The mitogenome was 16,716 bp in length and contained 13 protein-coding genes (PCGs), 22 tRNA genes, 2 rRNA genes, and a putative control region. The gene arrangement and orientation were identical with other Haliotis species. Phylogenetic tree was constructed based on 13 PCGs of 7 Haliotidae species to assess their phylogenetic relationship, the tree revealed that H. discus hannai was more closely to H. rufescens and H. iris.

A biologging technique for monitoring the egg-releasing behavior of Pacific abalone Haliotis discus hannai in the wild

A biologging technique for monitoring the egg-releasing behavior of Pacific abalone Haliotis discus hannai in the wild