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Prostaglandin E2 (PGE2) has been reported to be involved in reproduction as one of the most abundant and widely distributed prostaglandins in invertebrates. Regulating gonad development and gamete production in mollusks can greatly assist artificial breeding, which is believed to promote the commercial benefits of various mollusk species. In the present study, the contents of PGE2 in the gonads of abalone at different developmental stages (maturing stage, ripe stage, and spawning stage) and reproduction states (before and after spawning) were measured. A higher PGE2 level was found in the gonads of abalones at the ripe stage than other stages, and the highest PGE2 level was detected in the ovaries of female H. diversicolor in the UV-stimulated group. Then the effects of PGE2 injection on the spawning efficiency were explored, and the gamete emission rates of female and male abalone were significantly increased after PGE2 injection. Through qRT-PCR and in situ hybridization assay, higher expression levels and wide distribution of phospholipase A2 (PLA2), cyclooxygenase 2 (COX2), prostaglandin E synthases (PGES2), and prostaglandin E2 receptor 4 (EP4) in the gonads of H. diversicolor were observed after spawning. It is speculated that PGE2 may promote the reproductive cycle in both male and female H. diversicolor, although the regulation mechanism of PGE2 in female and male abalone might be different. The results will be useful for the application of PGE2 in the abalone aquaculture practices to increase the reproduction efficiency in future. [ABSTRACT FROM AUTHOR]

C-type lectins (CTLs), a member of pattern recognition receptors, play an important role in the innate immunity by recognizing invading microorganisms. In this study, a novel perlucin gene (designated as HdPer 3), a typical CTLs was cloned and characterized from the small abalone Haliotis diversicolor. The open reading frame of HdPer 3 was 471 bp, encoding a protein of 156 amino acids that included a single carbohydrate-recognition domain. HdPer 3 was widely expressed in all tested tissues and developmental stage. HdPer 3 expression was significantly up-regulated after Vibrio harveyi infection, suggesting that HdPer 3 was activated in response to bacterial infection. The encapsulation ability of hemocytes could be significantly enhanced by the recombinant protein HdPer 3 (rHdPer 3). To understand the regulation mechanism of the HdPer 3 , HdPer 3 was silenced in vivo by RNAi. Knocking down HdPer 3 decreased the hemocytes phagocytosis. Meanwhile, knocking down HdPer 3 can reduce the expression of 2 phagocytosis-related genes (Rab and Dynamin), TNF-α, and 2 MAPK pathway-related genes (MAPK-X1 and Ras) after V. harveyi infection. Moreover, HdPer 3 interference could increase the bacterial load in the hemolymph and the mortality of abalones after V. harveyi infection. All these results suggested that HdPer 3 played a crucial role in the defense against V. harveyi infection by recognizing bacterial pathogens and activating the expression of immune-related genes. • Identified a novel C-type lectin, perlucin, from the small abalone. • Knocking down HdPer 3 decreased phagocytosis. • Knocking down HdPer 3 increased the mortality of the small abalone after V. harveyi infection. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Taiwan Fisheries Research is the property of Fisheries Research Institute, Council of Agriculture, Executive Yuan and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Dalian Ocean University is the property of Journal of Dalian Ocean University Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Evident survival heterosis exists in the hybrid (HdDY) of two Haliotis diversicolor geographic genotypes (maternal genotype HdTW and paternal genotype HdJP). To explore the physiological basis underlying the heterosis, we compared the survival rate, cardiac performance, oxygen consumption rate, and ammonia excretion rate of the three H. diversicolor genotypes at the low temperature. After one year of cultivation in the abalone farm, the survival rates of HdTW, HdJP, and HdDY were 27.76%, 86.90%, and 88.57%, respectively. The 50% lethal low temperature (LLT50) of HdTW was higher than HdJP and HdDY. During low-temperature exposure, the abalone’s heartbeat variation pattern appeared as three stages: the heartbeat decreasing stage, arrhythmia stage, and cardiac recovery stage. Four cardiac indices were developed to compare the three genotypes’ cardiac differences: the low-temperature heartbeat decreasing rate (LDR), cardiac arrhythmia temperature (CAT), low-temperature heartbeat recovering rate (LRR), and cardiac recovery time (CRT). HdTW had lower LDR and higher CAT than HdJP and HdDY, while HdJP had lower LRR and higher CRT than HdTW and HdDY, suggesting the hybrid’s cardiac function is parent-like in low-temperature tolerance and mother-like in low-temperature recovery. Meanwhile, the heart rates of HdJP and HdDY were always higher than HdTW at both normal temperature (20 °C) and low temperature (12 °C). The oxygen consumption rate and ammonia excretion rate of HdJP and HdDY were also higher than HdTW after low-temperature exposure. The results indicate the hybrid’s advantageous respiratory and metabolic functions at low temperatures, which could be a vital physiological mechanism of the hybrid’s survival heterosis. This study elucidates the cardiac and respiratory metabolic differences among different abalone genotypes at low temperatures, which may help us understand the physiological basis of mollusks’ low-temperature tolerance. The evaluation protocol and indices developed in this study could be helpful in mollusks’ physiological researches, such as the low-temperature tolerance heterosis, low-temperature adaption, and habitat differentiation.

In recent years, more and more studies have shown that early pathogenic bacterial infection in invertebrates can enhance immunity and significantly reduce mortality when reinfected with the same pathogen. There are mechanisms to explain this phenomenon, but they are relatively few. In addition, dose-dependent primary infection is also associated with increased immunity. In the present study, the initial infection dose and mortality of abalone Haliotis diversicolor after reinfection with Vibrio harveyi were recorded, and the mechanism of immune enhancement was investigated by the transcriptomic response of abalone after two successive stimuli with V. harveyi. Priming with different concentrations of pathogen can enhance immunity; however, higher concentration is not always better. Compared with the first exposure, more genes were up-regulated after the second exposure. Among the commonly expressed genes, the immune related genes were significantly or persistently highly expressed after two infections and included pattern recognition receptors as well as immune effectors, such as toll-like receptors, perlucin 4, scavenger receptor class B-like protein, cytochrome P450 1B1-like, glutathione S-transferase 6, lysozyme and so on; in addition, these immune-related genes were mainly distributed in the pathways related to phagocytosis and calcium signaling. Among the specifically expressed genes, compared with the first infection, more genes were involved in the immune, metabolic and digestive pathways after the second infection, which would be more conducive to preventing the invasion of pathogens. This study outlined the mechanism of immune enhancement in abalone after secondary infection at the global molecular level, which is helpful for a comprehensive understanding of the mechanism of immune priming in invertebrates.

Heterosis is a widely distributed phenomenon in mollusks. It is vital in aquaculture by bringing beneficial traits into hybrids. People have utilized the heterosis theory in aquaculture for years. However, the molecular basis of heterosis remains elusive. Evident growth and survival heterosis were shown in the hybrid (“Dongyou-1”) of two Haliotis diversicolor geographic genotypes (Japan and Taiwan). To explore the molecular basis underlying the hybrid abalone’s heterosis, we conducted comparative mRNA and miRNA transcriptional analysis in the hybrid and parental genotypes. Differentially expression analysis identified 5,562 differentially expressed genes (DEGs) and 102 differentially expressed miRNAs (DEMs) between the three genotypes. 1,789 DEGs and 71 DEMs were found to be non-additively expressed in the hybrid. Meanwhile, both the expression level dominance pattern (ELD) and expression level overdominance pattern (ELOD) were found in the DEGs and DEMs, showing the existence of dominance and overdominance models in the hybrid’s transcriptome and post-transcriptional regulation. Functional analysis showed the non-additively expressed genes, ELD genes, and ELOD genes were significantly enriched in growth, immunity, and stress response related pathways, while some of the pathways were regulated by the mRNA-miRNA interactions. The expression levels of FGF, C1Q, HC, CAT, SEGPX, and MGST were significantly up-regulated in the hybrid compared to the middle parent value. In conclusion, we identified the existence of non-additivity, dominance, and overdominance models in the transcriptome and miRNAome of the H. diversicolor hybrid; these models facilitate the advantageous parental alleles’ integration into the hybrid, contributing to the hybrid’s growth and survival heterosis.

In recent years, more and more studies have shown that early pathogenic bacterial infection in invertebrates can enhance immunity and significantly reduce mortality when reinfected with the same pathogen. There are mechanisms to explain this phenomenon, but they are relatively few. In addition, dose-dependent primary infection is also associated with increased immunity. In the present study, the initial infection dose and mortality of abalone Haliotis diversicolor after reinfection with Vibrio harveyi were recorded, and the mechanism of immune enhancement was investigated by the transcriptomic response of abalone after two successive stimuli with V. harveyi. Priming with different concentrations of pathogen can enhance immunity; however, higher concentration is not always better. Compared with the first exposure, more genes were up-regulated after the second exposure. Among the commonly expressed genes, the immune related genes were significantly or persistently highly expressed after two infections and included pattern recognition receptors as well as immune effectors, such as toll-like receptors, perlucin 4, scavenger receptor class B-like protein, cytochrome P450 1B1-like, glutathione S-transferase 6, lysozyme and so on; in addition, these immune-related genes were mainly distributed in the pathways related to phagocytosis and calcium signaling. Among the specifically expressed genes, compared with the first infection, more genes were involved in the immune, metabolic and digestive pathways after the second infection, which would be more conducive to preventing the invasion of pathogens. This study outlined the mechanism of immune enhancement in abalone after secondary infection at the global molecular level, which is helpful for a comprehensive understanding of the mechanism of immune priming in invertebrates. [ABSTRACT FROM AUTHOR]

Bacteria affiliated to the Deltaproteobacteria dominate intestinal microbial communities in the abalone, Haliotis diversicolor, and may colonize the host's digestive gland, raising the possibility that they contribute to digestion of macroalgae. However, the phylogenetic, and genomic and metabolic characteristics of these Deltaproteobacteria, and the nature of their relationship to abalone host remain elusive. Here, we examined the intestinal microbial composition of H. diversicolor using high‐throughput sequencing and described the genomic characteristics of the Deltaproteobacteria phylotype using genome‐centric metagenomics. High‐throughput sequencing confirmed that one Deltaproteobacteria phylotype was predominant in intestinal microbiota of H. diversicolor. Phylogeny analysis based on full‐length 16S rRNA gene allocated this bacterium to a distinct and unique cluster within SAR324. It possessed a genome of at least 1.59 Mb with 35.15 mol% GC content, much smaller than other sequenced free‐living SAR324 bacteria. According to genome annotation and metabolic reconstruction, ATP binding cassette transporters for sugars and carbohydrate metabolism pathways indicated heterotrophic potential. Interestingly, it encoded polysaccharide lyases, which, if expressed, could help the host to digest its macroalgae diet. In contrast to the known SAR324, no sulphur oxidation or carbon fixation pathways were predicted. We propose that this is a unique and specific SAR324 bacterium in symbiosis with Haliotis. [ABSTRACT FROM AUTHOR]

Abstract This study was conducted to determine the influence of salinity on the growth of abalone Haliotis diversicolor Reeve, including the density and size of mucous cells. Abalone individuals were reared in the laboratory at salinities of 20, 25, 31, 35 and 40 ppt. The mucous cells of the lips, gills and digestive gut of H. diversicolor, which react to some forms of stress such as suboptimal salinity, were characterized following staining with Alcian Blue–Periodic Acid–Schiff`s Reagent (AB–PAS). The specific growth rate in wet weight and shell length of H. diversicolor were highest at 31 ppt and lowest at 20 ppt (0.52 vs 0.15% d−1, and 0.058 vs 0.021 mm d−1, respectively). The abalone H. diversicolor tolerated salinity fluctuations within the range of 20–40 ppt, but growth was optimum at 25–35 ppt. Mucous cells of the lips and gills showed significant differences (ANOVA, df = 4, P =

Macin is a family of antimicrobial peptides (AMPs) and is involved in the immune responses of marine mollusks. In the present study, a novel Mytimacin (denoted as Hd-mtmc 6) was identified from the small abalone Haliotis diversicolor by RNA-seq and RACE techniques. Hd-mtmc 6 contained a coding sequence of 243 bp and encoded 80 amino acids, with a putative peptide mytimacin 6 consisting of 61 amino acid residues. The mature peptide of Hdmtmc 6 exhibited typical characteristics of AMPs, including net positive charge (+4), higher hydrophobic residue ratio (37%), and lower molecular mass. Eight cysteines in the mature peptide formed four disulfide bond bridges (C1-C6, C2- C5, C3-C7, and C4-C8). Moreover, the presence of the macin domain, a threedimensional structure similar to that of hydramacin-1, and a phylogenetic relationship suggested that Hd-mtmc 6 could be a new member of the invertebrate macin family. In unchallenged abalone, the Hd-mtmc 6 transcript was expressed in all tested tissues and could be detected at different stages of embryonic development. Vibrio harveyi challenge caused a significant Hd-mtmc 6 transcripts upregulation within 2 - 6 h in the mantle and hepatopancreas. Our results suggested that Hd-mtmc 6 may be involved in innate immune responses of small abalone. Further investigations are required to confirm its antibacterial activity at the protein level. [ABSTRACT FROM AUTHOR]

This randomized, blinded study compared, contralaterally, the dimensions of supracrestal gingival tissue (SGT) in healthy human periodontium. Sulcular probing reaching the crestal bone was performed in 100 dental students (400 teeth [first molars and second premolars] and 1,600 sites). Contralateral measurements were statistically analyzed by one-way analysis of variance. SGT measurements ranged from 1.0 to 6.0 mm. Contralateral measurements showed no statistical difference (P = .096). Measurement of SGT contralaterally prior to crown lengthening or restorative procedures may dictate the needed amount of bone removal or tooth preparation into the sulcus. [ABSTRACT FROM AUTHOR]

Heavy metals in soil, water, and industrial production can affect the antibiotic resistance of bacteria. Antibiotic resistance in gut microbiota has been extensively researched. The effects of cadmium (Cd) was investigated on the gut microbiota and antibiotic resistance genes (ARGs) of Haliotis diversicolor , a commercially important abalone species. By exposing H. diversicolor to four concentrations of Cd (0 μg L−1 (control), 6.5 μg L−1 (low), 42.25 μg L−1 (medium), and 274.63 μg L−1 (high)) for 30 and 60 days, 16 types of ARG (aadA-01 , aadA-02 , cfr , dfrA1 , ermB , floR , folA , mecA , sul2 , tetB-01 , tetC-01 , tetD-01 , tetG-01 , tetM-02 , tetQ , vanC-01), and 1213 genus and 27 phylum microbiomes were detected. ARGs can be resistant to aminoglycoside, beta-lactamase, macrolide-lincosamide-streptogramin B, multidrug, florfenicol, macrolide, sulfonamides, tetracyclines, and vancomycin. Cadmium exposure significantly alters the abundance of tetC-01 , tetB-01 , tetQ , sul2 , and aadA-01. About 5% (61) of genus-level microorganisms were significantly affected by Cd exposure. Microbiota alpha and beta diversities in the 60-day 42.25 μg L−1 Cd treatment differed significantly from those in other treatments. In addition, 26 pathogens were detected, and two pathogens (Vibrio and Legionella) were significantly affected by Cd exposure. Significant correlations between pathogens and ARGs increased with increased Cd concentration after 60 days of Cd exposure. Cadmium exposure may cause gut microbiota disturbance in H. diversicolor and increase the likelihood of ARG transfer to pathogens, increasing potential ecological and economic risks. [Display omitted] • Cadmium exposure significantly altered the intestinal microbiota distribution. • Cadmium exposure alter the abundance of tetC-01, tetB-01, tetQ, sul2 and aadA-01. • Cadmium exposure was the driving factors for the variation of ARGs abundance. • Correlations between pathogens and ARGs increased with Cd concentration. [ABSTRACT FROM AUTHOR]

Abstract Background Haliotis diversicolor is commercially important species. The trochophore and veliger are distinct larval stages in gastropod development. Their development involves complex morphological and physiological changes. We studied protein changes during the embryonic development of H. diversicolor using two dimensional electrophoresis (2-DE) and label-free methods, tandem mass spectrometry (MS/ MS), and Mascot for protein identification. Results A total of 150 2-DE gel spots were identified. Protein spots showed upregulation of 15 proteins and downregulation of 28 proteins as H. diversicolor developed from trochophore to veliger larvae. Trochophore and veliger larvae were compared using a label-free quantitative proteomic approach. A total of 526 proteins were identified from both samples, and 104 proteins were differentially expressed (> 1.5 fold). Compared with trochophore larvae, veliger larvae had 55 proteins upregulated and 49 proteins downregulated. These differentially expressed proteins were involved in shell formation, energy metabolism, cellular and stress response processes, protein synthesis and folding, cell cycle, and cell fate determination. Compared with the 5 protein (fructose-bisphosphate aldolase, 14–3-3ε, profilin, actin-depolymerizing factor (ADF)/cofilin) and calreticulin) expression patterns, the mRNA expression exhibited similar patterns except gene of fructose-bisphosphate aldolase. Conclusion Our results provide insight into novel aspects of protein function in shell formation, torsion, and nervous system development, and muscle system differentiation in H. diversicolor larvae. “Quality control” proteins were identified to be involved in abalone larval development.

Due to increased temperatures and aquaculture density, thermal and hypoxia stresses have become serious problems for the aquaculture of abalone Haliotis diversicolor. Stresses lead to immunosuppression, which can cause severe negative impacts on aquaculture farms. To study the mechanism of immunosuppression after hypoxia stress and bacterial challenge, transcriptomes of H. diversicolor hemocytes involved in immunity were profiled. A total of 307,395,572 clean reads were generated and assembled into 99,774 unigenes. KEGG analysis indicated that 225 unigenes with immunologic function were mapped into immune-related pathways. Expression of 41 unigenes measured by quantitative real-time PCR (qRT-PCR) showed consistent results with that of transcriptome analysis. When exposure challenge of Vibrio parahaemolyticus, it is indicated that the PI3K-AKT, MAPK, NF-κB and P53 signal pathways were involved in the hypoxia-induced immunosuppression of H. diversicolor. Furthermore, when the AKT gene (HdAKT) was inhibited by double-stranded RNA (dsRNA), expression levels of HdAKT was lower than the blank and control group in hemocytes at 4 h, 12 h and 24 h (p < 0.05). [ABSTRACT FROM AUTHOR]

Copyright of South China Fisheries Science is the property of South China Fisheries Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Agricultural Science & Technology (1008-0864) is the property of Journal of Agricultural Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

As one of antimicrobial peptides (AMPs), defensins are involved in invertebrate innate immunity against invading pathogens. In this study, a member of the invertebrate defensins was cloned and characterized from the small abalone Haliotis diversicolor , designated HdDef-2. The HdDef-2 cDNA contained a 201 bp open reading frame encoding 66 amino acids including a signal peptide of 18 amino acids and a mature peptide of 48 amino acids. The mature peptide of HdDef-2 possessed similar features to other AMPs, such as lower molecular mass, net positive charge (+1), and a high hydrophobic residue ratio (45%). In addition, six cysteines in the mature peptide were arranged in the pattern C-X 16 -C-X 3 -C-X 9 -C-X 4 -C-X 1 -C and stabilized the α-helix/β-sheet motif (CSαβ) with three disulfide bonds (C1-C4, C2-C5 and C3-C6) in the predicted tertiary structure. Moreover, the similar three-dimensional structure to Anopheles gambiae defensin and a phylogenetic analysis suggest that HdDef-2 may be a new member of the arthropod defensin family. Quantitative real-time PCR analysis revealed that HdDef-2 transcripts were constitutively expressed in the mantle, gill, hepatopancreas, and foot, with the highest level in the hepatopancreas. It was observed that HdDef-2 transcripts were significantly induced in the hepatopancreas after infection by Vibrio harveyi. These results indicate that HdDef-2 may be involved in the immune response against invading pathogenic bacteria, but future work is needed to verify its antimicrobial activity in protein level and elucidate the underlying mechanisms. Unlabelled Image • Haliotis diversicolor defensin-2 (denoted as HdDef-2) shares the common features of antimicrobial peptides. • HdDef-2belongs to the arthropod defensins. • The main tissue expressing HdDef-2 was found to be the hepatopancreas. • HdDef-2 was significantly induced following Vibrio harveyi infection. [ABSTRACT FROM AUTHOR]

Abstract Hemocyanins (Hc), the main protein components of hemolymph in invertebrates, are not only involved in oxygen transport but also linked to non-specific immune responses. In this study, we used abalone (Haliotis diversicolor) Hc to study the basis of its diversified functions through gene, protein, peptides, and phenoloxidase (PO) activity levels. Three complete hemocyanin gene (HdH) sequences were cloned for the first time. By comparing the copies and location of HdH between abalone and other mollusks, we propose that Hc gene duplication and linkage is likely to be common during the evolution of mollusk respiratory proteins. We further demonstrate that all three genes could be expressed in abalone, with expression varying based on the developmental stages, tissue types, and different pathogen infections. However, HdH1 and HdH2 appear to be synthesized by the same cells by fluorescence in situ hybridization. Furthermore, the PO activity of HdH can be induced by trypsin, urea, and SDS in vitro. Viral infection can stimulate its PO activity in vivo by cleaving the protein into fragments. Consequently, we present a comprehensive study of abalone hemocyanin, providing important evidence for an in-depth understanding of the physiological and immune functions of Hc in mollusks. [ABSTRACT FROM AUTHOR]

The variously colored abalone Haliotis diversicolor is widely distributed in the northwest Pacific region and commonly occurs in shallow subtidal regions of Jeju Island, off the south coast of Korea. In this study, we first characterized the morphology and immune-related activities of H. diversicolor hemocytes using flow cytometry and light microscopy. Flow cytometry revealed three types of hemocytes in the hemolymph: granulocytes, hyalinocytes, and blast-like cells. Hyalinocytes were the largest and most abundant, while granulocytes were intermediate-sized and contained many granules in the cytoplasm. Flow cytometry indicated that granulocytes were mainly involved in phagocytosis and oxidative activities, although hyalinocytes also exhibited a certain level of immune-related activities. Blast-like cells were the smallest and exhibited a lack of phagocytosis and oxidative capacities. To understand the adaptive capacity to air exposure, abalones were exposed to air or humidity over 30 h. All abalones perished within 24 h after dry-air exposure, while 20% of abalones had survived under humid conditions by the end of the experiment. After 6 h of air exposure and 12 h of humidity, total hemocyte counts and phagocytosis capacity declined dramatically, and the level of hemocyte DNA damage increased significantly (P <.05). This study suggests that sufficient oxygen supply during transportation could enhance the survival of H. diversicolor , thereby improving its market value. • We first characterized types of hemocyte in the abalone Haliotis diversicolor using flow cytometry. • Granulocyte, hyalinocyte, and blast-cell like cell were identified, while the granulocyte were mainly involved in immune response. • After 6 h of air exposure, the immune capacities of the abalone declined dramatically and DNA damage increased significantly. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Haliotis diversicolor supertexta was highly susceptible to Haliotid herpesvirus 1 (HaHV-1-CN2003). • Haliotis discus hannai was not susceptible to HaHV-1-CN2003. • Tropism of HaHV-1-CN2003 included both neural tissue and haemocytes. Abstract Abalone viral ganglioneuritis (AVG), caused by Haliotid herpesvirus -1 (HaHV-1) infection, has been reported as the main cause of mortality and heavy losses of wild and cultivated abalone in Taiwan and Australia since 2003. HaHV-1 DNA has also been reported in diseased abalone collected in early 2000s in China. However, no data is available about the susceptibility, disease process and pathological changes of HaHV-1 infection in the primary cultivated abalone species in China. In the present study, two cultivated abalone species, Haliotis diversicolor supertexta and Haliotis discus hannai , were challenged with HaHV-1-CN2003 collected in 2003 in China using three different methods. Results showed that H. diversicolor supertexta was highly susceptible to HaHV-1-CN2003 infection and suffered acute mortality using all three challenge methods. H. discus hannai was not susceptible to the viral infection. Histopathology combined with transmission electron microscopy and quantitative PCR analysis revealed that the tropism of HaHV-1-CN2003 includes both neural tissue and haemocytes. [ABSTRACT FROM AUTHOR]

Abstract: Abalone (Haliotis diversicolor) is an important marine and mariculture food resource that has been severely affected by several viral disease outbreaks in recent years, and the virus causing the disease has not been unequivocally identified. To establish viral metagenomic research protocols for H. diversicolor, we applied differential centrifugation and sucrose gradient ultracentrifugation to obtain virus‐like particles from crude tissue extracts. After nuclease treatment to remove host nucleic acid, reverse transcription, and double‐stranded amplification, we used the HiSeq 2500 platform to generate a viral genome dataset. A total of 6,055,591,750 nucleotides were produced from 24,222,367 reads, generating 65,382 contigs, with a total sequence length of 14,239,389 bp. We analysed and evaluated the sequence data by quality control mapping, among other methods and the results indicated good quality data. Alignment of the data with sequences in the GenBank virus database identified homology with a large number of Abalone Herpes‐like Virus (AbHV) and Shriveling Syndrome‐associated Virus (AbSV) sequences, and also a certain amount of White Spot Syndrome Virus (WSSV) sequences. [ABSTRACT FROM AUTHOR]

There is growing interest in the use of probiotics as an alternative strategy for the promotion of growth rates and prevention of diseases in aquaculture. In this study, abalone Haliotis diversicolor were fed with different probiotic-supplemented diets for 180 days, containing Bacillus stratosphericus A3440, Phaeobacter daeponensis AP1220, and a mixture of the two strains. Probiotic supplementation significantly increased shell length and wet weight of juvenile abalone (p < 0.05). Compared with those non-treatment group, trypsin and lipase activities were increased significantly in the gastrointestinal tract of animals fed with A3440 or bacterial mixture (p < 0.05). A subsequent ten-day of challenging trial against Vibrio harveyi , the animals with AP1220 had ~90% survival rate as against ~60% survival rate for the non-treated animals. Likewise, in situ glutathione peroxidase, catalase, alkaline phosphatase, acid phosphatase, and superoxide dismutase assays showed that the probiotics significantly improved immune response of H. diversicolor (p < 0.05). 13,622 OTUs were obtained from abalone intestine microbiome by 16S rRNA high-throughput sequencing. Microbial diversity indices and richness estimates in the non-treated group declined before and after Vibrio infection trial. Conversely, these indexes enhanced to different levels in probiotics treatments, and the A3440 group restored and reached the highest value. Cluster analysis showed that probiotic could re-establish and subsequently balance the gut microbial community after the challenge trial. Furthermore, these potential probiotics had a positive effect on the number of beneficial endogenous bacteria in the abalone gut, such as bacilli and actinobacterial species. Thus, dietary administration of B. stratosphericus , P. daeponensis and their mixture could improve the nutrient and health status of abalone H. diversicolor . [ABSTRACT FROM AUTHOR]

Essences of small abalone (Haliotis diversicolor supertexta) were prepared by two methods, steaming and boiling. The chemical constituents and antioxidative properties of these essences were determined and compared to those of commercial freshwater clam essence (CFCE). Boiled small abalone essence (BSAE) contained more total soluble solids than steamed small abalone essence (SSAE). Total soluble solids and peptide content of both essences increased with longer extraction time. Glycogen contents of SSAE, BSAE, and CFCE were 14.01, 13.95, and 10.74 mg/mL, respectively. The concentrations of free amino acids in SSAE and BSAE (725.05 and 818.56 mg/100 g, respectively) were significantly higher than in CFCE (33.57 mg/100 g). The antioxidative properties of SSAE and BSAE were higher than that of CFCE. The reducing power and ferrous iron (Fe2+) chelating activity of 3-h SSAE were significantly higher than those of 10-min BSAE. The predominant free amino acid of both SSAE and BSAE was taurine (227.14-273.64 mg/100 g), followed by proline and arginine. Both essences also showed high correlations between peptide content and Fe2+ chelating activity and reducing power. Sensory evaluation trials suggested that 3-h SSAE is more favorable than BSAE in terms of appearance and overall acceptability. In conclusion, SSAE had better antioxidative properties and sensory scores than BSAE. [ABSTRACT FROM AUTHOR]

This study was conducted to determine the influence of salinity on the growth of abalone Haliotis diversicolor Reeve, including the density and size of mucous cells. Abalone individuals were reared in the laboratory at salinities of 20, 25, 31, 35 and 40 ppt. The mucous cells of the lips, gills and digestive gut of H. diversicolor, which react to some forms of stress such as suboptimal salinity, were characterized following staining with Alcian Blue-Periodic Acid-Schiff`s Reagent (AB-PAS). The specific growth rate in wet weight and shell length of H. diversicolor were highest at 31 ppt and lowest at 20 ppt (0.52 vs 0.15% d−1, and 0.058 vs 0.021 mm d−1, respectively). The abalone H. diversicolor tolerated salinity fluctuations within the range of 20-40 ppt, but growth was optimum at 25-35 ppt. Mucous cells of the lips and gills showed significant differences (ANOVA, df = 4, P = <0.001) in cell density and cell size, being less dense and larger at 31 ppt than at 40 ppt, which could be an effect of osmotic and ionic regulation. Consistent with reports in literature, salinity ranges of 25-35 ppt are suitable for growth of H. diversicolor. Results of this study indicated that areas with such salinity are favorable for stock enhancement and mariculture of the abalone H. diversicolor. [ABSTRACT FROM AUTHOR]

Background: Haliotis diversicolor is commercially important species. The trochophore and veliger are distinct larval stages in gastropod development. Their development involves complex morphological and physiological changes. We studied protein changes during the embryonic development of H. diversicolor using two dimensional electrophoresis (2-DE) and label-free methods, tandem mass spectrometry (MS/MS), and Mascot for protein identification. Results: A total of 150 2-DE gel spots were identified. Protein spots showed upregulation of 15 proteins and downregulation of 28 proteins as H. diversicolor developed from trochophore to veliger larvae. Trochophore and veliger larvae were compared using a label-free quantitative proteomic approach. A total of 526 proteins were identified from both samples, and 104 proteins were differentially expressed (> 1.5 fold). Compared with trochophore larvae, veliger larvae had 55 proteins upregulated and 49 proteins downregulated. These differentially expressed proteins were involved in shell formation, energy metabolism, cellular and stress response processes, protein synthesis and folding, cell cycle, and cell fate determination. Compared with the 5 protein (fructosebisphosphate aldolase, 14-3-3e, profilin, actin-depolymerizing factor (ADF)/cofilin) and calreticulin) expression patterns, the mRNA expression exhibited similar patterns except gene of fructose-bisphosphate aldolase. Conclusion: Our results provide insight into novel aspects of protein function in shell formation, torsion, and nervous system development, and muscle system differentiation in H. diversicolor larvae. "Quality control" proteins were identified to be involved in abalone larval development. [ABSTRACT FROM AUTHOR]

RHEB ( R as H omolog E nriched in B rain) is a GTP-binding protein that is ubiquitously expressed in humans and other mammals. The protein is largely involved in the mechanistic target of rapamycin (mTOR) pathway, and regulates the cell cycle progression and growth. The goal of this study was to characterize the RHEB gene in the small abalone Haliotis diversicolor , and identify the responses of RHEB gene to stresses of hypoxia or/and thermal. The objectives were to: 1) clone the full-length cDNA RHEB gene in the H. diversicolor ( HdRHEB ); 2) quantify the expression of HdRHEB gene in tissues of haemocytes, mantle, kidney, gill, digestive tract, colleterial gland, and hepatopancreas by using RT-PCR, and 3) evaluate the responses of HdRHEB in gill and haemocyte to stresses of hypoxia (0.2 mg/l00 ml), thermal (31 °C), and combination of hypoxia (0.4 mg/l00 ml) and thermal (30 °C) at exposure time of 0, 4, 24, 96, and 192 h. The full length cDNA of HdRHEB was 1044 bp encoding a peptide of 182 amino acid residues. Expression of HdRHEB gene was detected in all of the 7 tissues and showed the highest in mantle ( P < 0.05). Under hypoxia, expression of HdRHEB in gill increased significantly at 4 h, 24 h and 96 h ( P < 0.05), and that in haemocyte increased significantly at 24 h, 96 h and 192 h ( P < 0.05). Under thermal stress, expression of HdRHEB gene in gill decreased significantly at 4 h and 24 h, while expression in haemocyte decreased significantly all the time. Under thermal and hypoxia stresses, expression of HdRHEB gene in gill and haemocyte was up-regulated significantly at 24 h and 96 h ( P < 0.05). The results in this study demonstrated for the first time that RHEB gene in abalones is able to response to stress stimuli of hypoxia or/and thermal. [ABSTRACT FROM AUTHOR]

Small abalone (Haliotis diversicolor) is a commercially valuable species for both fisheries and aquaculture. The production of annual farmed small abalone in Taiwan, once the highest in the world, has dramatically decreased in the past 15 years, and currently, the industry is close to collapse. Understanding the genetic diversity of small abalone and developing stock identification methods will be useful for genetic breeding, restoring collapsed stocks, managing stocks, and preventing illegal trade. We investigated 307 cultured and wild individuals from Taiwan, Japan, and Bali Island (Indonesia) by using the mitochondrial cytochrome c oxidase subunit I (COI) gene. Network analysis of mtDNA COI gene sequences revealed that the individuals collected from Taiwan, Japan, and Indonesia could be identified, and showed significant genetic divergence. In addition, the Indonesian population (Haliotis diversicolor squamata) was significantly different from the other populations and might need to be considered a separate species. We discovered a single nucleotide polymorphism marker in the mtDNA COI gene that can be used to distinguish the Taiwan population from the Japan population. We also developed a polymerase chain reaction-restriction fragment length polymorphism method for rapid detection. Furthermore, we could identify the cultured stocks, wild population, and hybrid stocks by using 6 microsatellites and amplified fragment length polymorphism. This study contributes useful tools for stock identification and the production of high-disease resistant small abalone strains (Japan × Taiwan or Taiwan × Japan). Efforts should be made to avoid unintentional random genetic mixing of the Taiwan population with the Japan population and subsequent breakdown of population differentiation, which impair local adaptation of the Taiwan wild population. Molecular markers revealed a split between the Taiwan and Japan populations, and the existence of a possible barrier to the free dispersal of small abalone is discussed. [ABSTRACT FROM AUTHOR]

Heat-shock protein 70 (HSP70) is a molecular chaperone that plays critical roles in cell protein folding and metabolism, which helps to protect cells from unfavorable environmental stress. Haliotis diversicolor is one of the most important economic breeding species in the coastal provinces of south China. To date, the expression and transcriptional regulation of HSP70 in Haliotis diversicolor (HdHSP70) has not been well characterized. In this study, the expression levels of HdHSP70 gene in different tissues and different stress conditions were detected. The results showed that the HdHSP70 gene was ubiquitously expressed in sampled tissues and was the highest in hepatopancreas, followed by hemocytes. In hepatopancreas and hemocytes, the HdHSP70 gene was significantly up-regulated by Vibrio parahaemolyticus infection, thermal stress, and combined stress (Vibrio parahaemolyticus infection and thermal stress combination), indicating that HdHSP70 is involved in the stress response and the regulation of innate immunity. Furthermore, a 2383 bp of 5′-flanking region sequence of the HdHSP70 gene was cloned, and it contains a presumed core promoter region, a CpG island, a (TG)39 simple sequence repeat (SSR), and many potential transcription factor binding sites. The activity of HdHSP70 promoter was evaluated by driving the expression of luciferase gene in HEK293FT cells. A series of experimental results indicated that the core promoter region is located between −189 bp and +46 bp, and high-temperature stress can increase the activity of HdHSP70 promoter. Sequence-consecutive deletions of the luciferase reporter gene in HEK293FT cells revealed two possible promoter activity regions. To further identify the binding site of the key transcription factor in the two regions, two expression vectors with site-directed mutation were constructed. The results showed that the transcriptional activity of NF-1 site-directed mutation was significantly increased (p < 0.05), whereas the transcriptional activity of NF-κB site-directed mutation was significantly reduced. These results suggest that NF-1 and NF-κB may be two important transcription factors that regulate the expression of HdHSP70 gene.

Organotin compounds, especially tributyltin (TBT) and triphenyltin (TPT), are a group of hazardous pollutants in marine environments. Haliotis diversicolor is an important marine model organism for environmental science. In this study, 1 H NMR spectroscopy together with pattern recognition methods was used to investigate the responses of hepatopancreas and gill of Haliotis diversicolor to TBT and TPT exposure. It was found that obvious gender-, tissue- and compound-specific metabolomic alterations were induced after a 28-day exposure. TBT and TPT exposure not only caused the disturbance in energy metabolism and osmotic balance in hepatopancreas and gill tissues with different mechanisms, but also induced oxidative stresses. These metabolic alterations were highlighted in the accumulation of aspartate, uridine diphosphate-N-acetylglucosamine, uridine diphosphate glucose, guanosine and the depletion of leucine, isoleucine, valine, malonate, homarine, trigonelline in all exposure gills, as well as in the depletion of ATP, AMP, betaine in male exposure gills and pantothenate in male exposure hepatopancreases. The significant decreased aromatic amino acids (AAAs), lysine and glutamate in gills and increased betaine in hepatopancreases for TPT exposure together with increased glutamate and decreased betaine in gills and increased glutamate and glycine in hepatopancreases for TBT exposure demonstrated their specific metabolic characteristics. Among these characteristic metabolites, AAAs, lysine and glutamate in the gill as well as pantothenate in the hepatopancreas might be identified as potential biomarkers for TPT or TBT exposure in Haliotis diversicolor . The results provide a useful insight into the toxicological mechanisms of organotin compounds on Haliotis diversicolor . [ABSTRACT FROM AUTHOR]

Vibrio parahemolyticus is a devastating bacterial pathogen that often causes outbreak of vibriosis in abalone Haliotis diversicolor. Elucidation of metabolic mechanisms of abalones in responding to V . parahemolyticus infection is essential for controlling the epidemic. In this work, 1 H NMR-based metabolomic techniques along with correlation and network analyses are used to investigate characteristic metabolites, as well as corresponding disturbed pathways in hepatopancreas and gill of H . diversicolor after V . parahemolyticus infection for 48 h. Results indicate that obvious gender- and tissue-specific metabolic responses are induced. Metabolic responses in female abalones are more clearly observed than those in males, which are primarily manifested in the accumulation of branched-chain amino acids and the depletion of organic osmolytes (homarine, betaine and taurine) in the infected gills of female abalones, as well as in the depletion of glutamate, branched-chain and aromatic amino acids in the infected hepatopancreases of female abalones. Moreover, based on major metabolic functions of the characteristic metabolites, we have found that V . parahemolyticus infection not only cause the disturbance in energy metabolism, nucleotide metabolism and osmotic balance, but also induce oxidative stress, immune stress and neurotoxic effect in different tissues with various mechanisms. Our study provides details of metabolic responses of abalones to V . parahemolyticus infection and will shed light on biochemical defence mechanisms of male and female hosts against pathogen infection. [ABSTRACT FROM AUTHOR]

The PI3K-AKT signal pathway has been found to be involved in many important physiological and pathological processes of the innate immune system of vertebrates and invertebrates. In this study, the AKT ( HdAKT ) and PI3K ( HdPI3K ) gene of small abalone Haliotis diversicolor were cloned and characterized for the important status of PI3K and AKT protein in PI3K-AKT signaling pathway. The full length cDNAs of HdAKT and HdPI3K are 2126 bp and 6052 bp respectively, encoding proteins of 479 amino acids and 1097 amino acids, respectively. The mRNA expression level of fourteen genes in the PI3K-AKT signaling pathway were detected by quantitative real-time PCR. The results showed that all these fourteen genes were ubiquitously expressed in seven selected tissues. Meanwhile, HdAKT was expressed in haemocytes with the highest expression level (p < 0.05) next in hepatopancreas (p < 0.05). On the other hand, the expression level of HdPI3K in haemocytes was higher than other tissues. Under normal condition, the gene expression level of HdAKT, HdPI3K , and other PI3K-AKT signaling pathway members were significantly up-regulated by Vibrio parahaemolyticus infection which demonstrated that HdAKT, HdPI3K , and other PI3K-AKT signaling pathway members play a role in the innate immune system of abalone. The mRNA expression of these genes in gills, haemocytes and hepatopancreas was significantly down-regulated after the Vibrio parahaemolyticus stimulation with environment stimulation (thermal, hypoxia and thermal & hypoxia). These results indicate that the dual/multiple stresses defeat the immune system and lead to immunosuppression in abalone. PI3K-AKT signaling pathway may be involved in hypoxia/thermal-induced immunosuppression of small abalone Haliotis diversicolor. [ABSTRACT FROM AUTHOR]

Background: The shell of, or shijueming (SJM), is a type of traditional Chinese medicine. The Haliotis diversicolor SJM has appeared in historical records as early as the third and fourth centuries. Historical records have revealed that SJM had mainly been used to treat eye diseases. After the Qing Dynasty (1757), records had emerged, detailing the use of SJM for treating skin injuries, particularly for treating poorly managed ulcers or traumatic wounds. Furthermore, in our anti-inflammation-screening system, SJM significantly inhibited the expression of pro-inflammatory proteins. Previous studies have yet to adopt an animal model to verify the phenomenon and described in the historical records regarding the efficacy of SJM in promoting wound healing. Besides, the mechanism of wound healing effect of SJM is also not clear. Methods: This study applied in vitro and in vivo models, tissue section analysis, and western blotting to evaluate the effect of SJM on wound healing. The RAW 264.7 cells were used in anti-inflammatory activity assay and phagocytic assay. Male Wistar rats were used to evaluate the effect of SJM on burn injury healing. A copper block (2 x 2 cm, 150 g) preheated to 165 °C in a dry bath was used to contact the skin area for 10 s, thus creating a full-thickness burn injury. The results were analyzed by hematoxylin and eosin staining, picrosirius red staining and Western blotting. Results: The results revealed that in the in vitro model, the presence of SJM decreased the inducible nitric oxide synthase (iNOS) expression and enhanced the functions of macrophages. The results of the rat burn injury model revealed that SJM decreased neutrophil infiltration, promoted wound healing, thus increasing the collagen I content and promoting the expression of transforming growth factor-beta 1 (TGF-β1) protein. We speculate that the effect and mechanism of SJM on promoting wound healing is related to macrophage activation. In the inflammation phase, SJM alleviates inflammation by inhibiting iNOS expression and removing neutrophils through phagocytosis. Furthermore, SJM induces the secretion of TGF-β1, converting collagen during the tissue remodeling phase. Conclusions: According to our review of relevant literature, this is the first study that applied an evidence-based method to verify that SJM alleviates inflammation, enhances phagocytosis, and triggers wound healing after burn injury. The study findings reveal that SJM provides a promising therapeutic option for treating burn injury. [ABSTRACT FROM AUTHOR]

The small abalone ( Haliotis diversicolor) is a mollusc and was cultured in south of china. Problems such as the decreasing pathogen-resistance and their mass mortality during the summer. The increased immunity of small abalone populations is a key factor in resolving these problems. Thus, the study of immunity-related genes in small abalone has become important. In this study, three bacterial species were initially isolated from small abalone carcasses. The regression of infection was analysed, which revealed that the bacteria species could cause rapid morbidity in small abalone. A QM-like gene ( Hdi QM) was found and bacterial challenge tests showed that Hdi QM gene expression was induced by the bacterial isolates from small abalone carcasses. Therefore, our results implied that Hdi QM was found to be an inflammatory stress-inducible gene associated with pathogen infection, with important functions in small abalone immunity. [ABSTRACT FROM AUTHOR]

This research aims to investigate the non-specific immune response of Taiwan abalone ( Haliotis diversicolor supertexta ) which was treated with the beta-1,3-1,6-glucan to be observed in the survival impact after the Vibrio alginolyticus infection. The non-specific immune and physiological response of superoxide anion radical (O 2 − ), phenoloxidase (PO), phagocytic index (PI), phagocytic rate (PR) and lucigenin-chemiluminescence for reactive oxygen intermediates (ROIs) were enhanced via in-vitro experiment. In the in-vivo experiment, the observed data presented that the haemolymph lysate supernatant (HLS), superoxide dismutase (SOD), glutamate oxalacetate transaminase (GOT) and glutamate pyruvate transaminase (GPT) were not significant enhanced, but the total haemocyte count (THC), O 2 − , PO, phagocytic index (PI), phagocytic ratio (PR) and other parameters of immune were significantly promoted after treated with beta-1,3-1,6-glucan. In the challenge experiment, the survival rates of abalone in the 40 and 80 μl/ml groups of beta-1,3-1,6-glucan were observed from 6.67% up to 33.33% and 36.67% after injection with Vibrio alginolyticus , respectively. [ABSTRACT FROM AUTHOR]

Accumulating data has demonstrated that ferritin plays an important role in host defense responses against infection by pathogens in many organisms. In this study, ultracentrifugation was used to isolate ferritin from abalone, Haliotis diversicolor , and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis revealed that this ferritin consisted of two subunits (designated as HdFer1 and HdFer2). There are no disulfide bonds between the HdFer1 and HdFer2 subunits; however, these subunits co-assemble to form heteropolymers. A novel ferritin subunit (HdFer2) was cloned from H. diversicolor by 5ʹ and 3ʹ RACE (rapid amplification of cDNA ends) approach. The full-length HdFer2 cDNA sequence consists of 878 bp with an open reading frame of 513 bp that encodes a protein that is 170 amino acids in length. Quantitative real-time PCR analysis revealed that HdFer1 and HdFer2 were transcribed in various tissues, such as the mantle, gill and hepatopancreas, with the highest levels of expression in the hepatopancreas. Following a challenge with the pathogen, Vibrio harveyi , the expression of HdFer1 and HdFer2 were markedly induced at different times. This study has identified a novel ferritin subunit in H. diversicolor which will contribute to further exploration of the role of ferritin in mollusk innate immune defense against invading pathogens. [ABSTRACT FROM AUTHOR]

Using two-dimensional gel electrophoresis, the foot muscle proteome of three geographical populations of Haliotis diversicolor were examined, with a total of 922 ± 21 protein spots detected in the Japanese population ( JJ), 904 ± 25.6 in the Taiwanese population ( TT), and 936 ± 16.2 in the Vietnamese population ( VV). Of these, 254 spots showed differential expression and 85 protein spots percentage volumes varied more than twofold. Both 'genotype' and 'spot' analysis of variance approaches significantly showed differences among the three populations. Hierarchical clustering analysis showed that TT and VV clustered together followed by clustering with JJ, which is consistent with their geographical location. Following matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, 30 differentially expressed proteins involved in major biological processes including energy production and storage and stress response were identified. Of these proteins, proteins pertaining to muscle contraction and muscle protein regulation showed highest expression levels in VV samples. Proteins involved in energy production and storage, including ATP synthase beta subunit, fructose-1,6-bisphosphate aldolase, arginine kinase, enolase, triosephosphate isomerase, and tauropine dehydrogenase, showed diverse expression patterns among the three populations. For stress-responsive proteins, the expression of heat shock protein 70 was JJ > VV > TT. The expression pattern of Cu/Zn-superoxide dismutase was JJ > VV > TT. Overall, these results may aid in the detection of new differentially expressed proteins within three different abalone populations. [ABSTRACT FROM AUTHOR]

Haliotis diversicolor is a commercially important cultured shellfish. It is also an important marine model organism for environmental science. High temperature accompanied with hypoxia frequently induces diseases or even death to abalones. In present study, 1 H NMR spectroscopy together with pattern recognition methods was used to investigate the responses of muscle and gill of H. diversicolor to thermal and hypoxic stresses. It was found that obvious gender-, time- and tissue-specific metabolic responses were induced by thermal and hypoxic stresses. In combination with the changes of H. diversicolor in physiological features, the dual-modal stresses were suggested to mainly cause the disturbance in energy metabolism and osmotic balance in muscle and gill tissues with different mechanisms. Further, the corresponding correlation networks and metabolic pathways derived from the characteristic metabolites were used to assess the major metabolic functions of these characteristic metabolites. These findings shed some lights on the metabolic influences of environmental stresses on marine organisms. [ABSTRACT FROM AUTHOR]

The small abalone ( Haliotis diversicolor ) is an important aquaculture species in southern China. Traditional breeding programs have been implemented for this species. But due to long reproduction cycle of the small abalone, the traditional method takes too long. There is therefore an urgent need to accelerate molecular breeding in H. diversicolor. Here we report on the construction of a high-density genetic map and quantitative trait loci detection in the small abalone using an F1 cross population with 131 progeny based on restriction-site-associated DNA sequencing. The sex-averaged map spanned 2190.1 cM with a mean distance between single nucleotide polymorphisms (SNPs) of 0.59 cM. A total of 3717 SNPs were mapped on 16 linkage groups. There were 1728 SNPs on the female map and 2673 SNPs on the male map. The total length of the female and male map was 2197.8 and 1764.7 cM, respectively. Six growth-related traits (body weight, muscle weight, shell weight, shell length, shell width and shell height) were recorded to detect QTL. A total of 15 suggestive QTL were identified and most of them were found on LG11. A consensus QTL for six growth-related traits was detected on LG11. It suggests that these traits may be controlled by a common region. Our results would provide valuable tools which can be used for Marker-Assisted Selection (MAS) in breeding programs of H. diversicolor . Statement of relevance This paper published a high-density linkage map and QTL analysis for growth-related traits. The study will be valuable tools for in Marker-Assisted Selection breeding program in Haliotis diversicolor . [ABSTRACT FROM AUTHOR]

Abalone withering syndrome is a serious chronic disease. Ultrastructure and pathological changes were studied using transmission electron microscopy. Myofibers appeared hollow, and the number of inner intact myofibrils was reduced greatly. The morphology of mitochondria in cells appeared abnormal. Crystal lattice-like inclusions in pathological muscle cells were observed. The hepatopancreas was damaged severely; it was full of empty vesicles and devoid of any recognizable cellular structures. The activities of 3 enzymes, acid phosphatase (ACP), alkaline phosphatase (AKP), and total superoxide dismutase (T-SOD), in hemolymph of healthy and diseased abalone showed little differences. ACP activity in the pedal mucus of healthy and diseased abalone was not significantly different. However, in diseased abalone pedal mucus, activities of AKP and T-SOD were significantly lower than in the control group. In pedal mucus of healthy and diseased abalone, the differential (SDS-PAGE) bands were identified as actin and hemocyanin. Protein identification was accomplished with mass spectrometry. A total of 16 2-DE gel spots were identified; 5 gel spots showed upregulation and 11 gel spots showed downregulation in diseased abalone. Proteins involved in energy production and storage, including fructose-1, 6-bisphosphate aldolase, arginine kinase, and triosephosphate isomerase, showed diverse expression patterns in diseased abalone. For stress-responsive proteins, expression of Cu/Zn-superoxide dismutase showed downregulation. For contraction and regulation proteins of muscle, actin showed significant downregulation. Statement of relevance Abalone withering syndrome (WS) is a serious chronic disease. However, there is limited information on the physiological performance of infected abalones. The present study was to assess the alterations of Haliotis diversicolor caused by WS using transmission electron microscopy as well as assess the immune enzyme activity of hemolymph and mucus, and muscle, mucus proteins changes by 2-DE and SDS-PAGE. [ABSTRACT FROM AUTHOR]

The small abalone ( Haliotis diversicolor) is one of the most important aquaculture species in East Asia. To facilitate gene cloning and characterization, genome analysis, and genetic breeding of it, we constructed a large-insert bacterial artificial chromosome (BAC) library, which is an important genetic tool for advanced genetics and genomics research. The small abalone BAC library includes 92,610 clones with an average insert size of 120 Kb, equivalent to approximately 7.6× of the small abalone genome. We set up three-dimensional pools and super pools of 18,432 BAC clones for target gene screening using PCR method. To assess the approach, we screened 12 target genes in these 18,432 BAC clones and identified 16 positive BAC clones. Eight positive BAC clones were then sequenced and assembled with the next generation sequencing platform. The assembled contigs representing these 8 BAC clones spanned 928 Kb of the small abalone genome, providing the first batch of genome sequences for genome evaluation and characterization. The average GC content of small abalone genome was estimated as 40.33 %. A total of 21 protein-coding genes, including 7 target genes, were annotated into the 8 BACs, which proved the feasibility of PCR screening approach with three-dimensional pools in small abalone BAC library. One hundred fifty microsatellite loci were also identified from the sequences for marker development in the future. The BAC library and clone pools provided valuable resources and tools for genetic breeding and conservation of H. diversicolor. [ABSTRACT FROM AUTHOR]