Laju Pertumbuhan Kerang Abalon Haliotis squamata Melalui Budidaya IMTA (Integrated Multi Trophic Aquaculture di Pantai Geger, Nusa Dua, Kabupaten Badung, Provinsi Bali

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Heny Hayati

2017-11-01

Full Text Available Abalone is an important non fishery commodity that has high potential value to be developed. Abalone culture still faces some problems, such as, relatively slow growth rate, low survival rate and causing environmental pollution. One of the efforts to tackle the problems, is applying the culture system that is environmental friendly, such as IMTA (Integrated Multitrophic Aquaculture. This research aims to identify the growth rate and survival rate of the abalone (Haliotis squamata and the suitability of chemical and physical environment parameter supporting the integration culture of abalone and seaweed (Gracilaria sp on different stocking density at Geger beach, Nusa Dua, Bali. This research was performed in 45 days using a complete randomized design method that consist of three treatments and three repetition. The result showed that the highet growth rate was on treat ment T3 which consisted of abalone (Haliotis squamata 40 individu and 10 bunches of seaweed (Gracilaria sp 100 grams weight/each individu (0.76%/day, then It followed by T2 treatment that was integrated with 10 bunches of seaweed 50 grams (0.71%/day. The lowest growth rate observed on treatment T1 (control/monoculture which consisted of 40 individu abalone (Haliotis squamata (0.59%/day. The highest survival rate found on treatment T2 (97.5% and followed by treatment T1 as control (94.5%, while the lowest number was found on treatment T3 (83.3%. Physical chemical water quality parameters showed that It supported the growth of both, abalone (Haliotis squamata and seaweed (Gracilaria sp. at Geger Beach, Nusa Dua, Badung Regency, Bali Province.

SNP discovery and High Resolution Melting Analysis from massive transcriptome sequencing in the California red abalone Haliotis rufescens.

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Valenzuela-Muñoz, Valentina; Araya-Garay, José Miguel; Gallardo-Escárate, Cristian

2013-06-01

The California red abalone, Haliotis rufescens that belongs to the Haliotidae family, is the largest species of abalone in the world that has sustained the major fishery and aquaculture production in the USA and Mexico. This native mollusk has not been evaluated or assigned a conservation category even though in the last few decades it was heavily exploited until it disappeared in some areas along the California coast. In Chile, the red abalone was introduced in the 1970s from California wild abalone stocks for the purposes of aquaculture. Considering the number of years that the red abalone has been cultivated in Chile crucial genetic information is scarce and critical issues remain unresolved. This study reports and validates novel single nucleotide polymorphisms (SNP) markers for the red abalone H. rufescens using cDNA pyrosequencing. A total of 622 high quality SNPs were identified in 146 sequences with an estimated frequency of 1 SNP each 1000bp. Forty-five SNPs markers with functional information for gene ontology were selected. Of these, 8 were polymorphic among the individuals screened: Heat shock protein 70 (HSP70), vitellogenin (VTG), lysin, alginate lyase enzyme (AL), Glucose-regulated protein 94 (GRP94), fructose-bisphosphate aldolase (FBA), sulfatase 1A precursor (S1AP) and ornithine decarboxylase antizyme (ODC). Two additional sequences were also identified with polymorphisms but no similarities with known proteins were achieved. To validate the putative SNP markers, High Resolution Melting Analysis (HRMA) was conducted in a wild and hatchery-bred population. Additionally, SNP cross-amplifications were tested in two further native abalone species, Haliotis fulgens and Haliotis corrugata. This study provides novel candidate genes that could be used to evaluate loss of genetic diversity due to hatchery selection or inbreeding effects. Copyright © 2013 Elsevier B.V. All rights reserved.

Uptake of technetium from seawater by red abalone Haliotis rufescens

International Nuclear Information System (INIS)

Spies, R.B.

1975-01-01

Technetium accumulation from seawater by the abalone Haliotis rufescens was studied with 95 Tc. Concentration factors, uptake rates, steady state concentrations, and biological half-lives were determined experimentally for whole-body uptake. Whole-body concentration factors ranged from 135 to 205; biological half-life was 60 days. Changes in concentration factors were determined for six tissues during the uptake period. The highest activities were in the order of: digestive gland>gill>kidneys>heart>gonad>columnar muscle. Dead shells accumulated little activity compared to shells of living abalone. Gills and digestive system appear to be the routes of entry. Autoradiography shows that of the muscular tissues the outer edge of the foot and epipodium are the most active and the edible columnar muscle the least active. (author)

Kazal-type proteinase inhibitor from disk abalone (Haliotis discus discus): molecular characterization and transcriptional response upon immune stimulation.

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Wickramaarachchi, W D Niroshana; De Zoysa, Mahanama; Whang, Ilson; Wan, Qiang; Lee, Jehee

2013-09-01

Proteinases and proteinase inhibitors are involved in several biological and physiological processes in all multicellular organisms. Proteinase inhibitors play a key role in regulating the activity of the respective proteinases. Among serine proteinase inhibitors, kazal-type proteinase inhibitors (KPIs) are widely found in mammals, avians, and a variety of invertebrates. In this study, we describe the identification of a kazal-type serine proteinase inhibitor (Ab-KPI) from the disk abalone, Haliotis discus discus, which is presumably involved in innate immunity. The full-length cDNA of Ab-KPI includes 600 bp nucleotides with an open reading frame (ORF) encoding a polypeptide of 143 amino acids. The deduced amino acid sequence of Ab-KPI contains a putative 17-amino acid signal peptide and two tandem kazal domains with high similarity to other kazal-type SPIs. Each kazal domain consists of reactive site (P1) residue containing a leucine (L), and a threonine (T) located in the second amino acid position after the second conserved cysteine of each domain. Temporal expression of Ab-KPI was assessed by real time quantitative PCR in hemocytes and mantle tissue following bacterial and viral hemorrhagic septicemia virus (VHSV) challenge, and tissue injury. At 6 h post-bacterial and -VHSV challenge, Ab-KPI expression in hemocytes was increased 14-fold and 4-fold, respectively, compared to control samples. The highest up-regulations upon tissue injury were shown at 9 h and 12 h in hemocytes and mantle, respectively. The transcriptional modulation of Ab-KPI following bacterial and viral challenges and tissue injury indicates that it might be involved in immune defense as well as wound healing process in abalone. Copyright © 2013 Elsevier Ltd. All rights reserved.

The distribution of heavy metals in the red abalone, haliotis rufescens, on the california coast

Energy Technology Data Exchange (ETDEWEB)

Anderlini, V.

1974-01-01

The gills, mantle, digestive gland, and foot muscle of 74 specimens of the red abalone, haliotis rufescens, from five localities on the california coast are analyzed for eight heavy metals. The distribution of these elements in the abalones appears to be non-normal. High lead concentrations in the la jolla-long beach area seem to reflect pollutant inputs; elsewhere lead levels appear to derive from natural sources. (1 graph, 1 map, 31 references, 1 table)

STIMULASI PERTUMBUHAN JUVENIL ABALON, Haliotis squamata DENGAN PEMBERIAN HORMON REKOMBINAN IKAN rElGH

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Fitriyah Husnul Khotimah

2017-01-01

Full Text Available Masalah yang paling utama dalam budidaya abalon tropis adalah pertumbuhan yang lambat. Penggunaan rElGH (recombinant giant grouper, Epinephelus lanceolatus growth hormone untuk menstimulasi pertumbuhan beberapa spesies ikan sudah dilakukan. Penelitian ini bertujuan untuk menguji akselerasi pertumbuhan juvenil abalon tropis, Haliotis squamata setelah diberi perlakuan perendaman hormon rekombinan ikan kerapu kertang, Epinephelus lanceolatus pada frekuensi yang berbeda. Ada empat perlakuan frekuensi perendaman rElGH yaitu 4, 9, 16 kali, dan tanpa perendaman (kontrol. Masing-masing perlakuan diulang tiga kali. Perendaman dilakukan selama tiga jam, dengan interval waktu empat hari. Kepadatan abalon tropis 100 ekor/L air laut yang mengandung 30 mg rElGH. Wadah untuk perendaman berupa beaker glass yang dilengkapi dengan aerasi. Penelitian dilakukan selama tujuh bulan. Hasil penelitian menunjukkan bahwa abalon tropis yang direndam rElGH dengan frekuensi empat kali menghasilkan pertumbuhan bobot tubuh dan panjang cangkang tertinggi dan berbeda nyata dengan perlakuan lainnya (P<0,05. Sintasan abalon tropis yang diberi perlakuan perendaman hormon rElGH lebih tinggi dibandingkan perlakuan kontrol. The most crucial problem in tropical abalone aquaculture is the slow growth of the species. Studies investigating the use of rElGH (recombinant giant grouper, Epinephelus lanceolatus growth hormone for promoting growth have been performed in various species. This research aimed to examine the growth acceleration of tropical abalone, Haliotis squamata juvenile after being treated in different immersion frequencies of recombinant giant grouper, Epinephelus lanceolatus growth hormone (rElGH. There were four treatments of rElGH immersion frequency: 4, 9, 16 times and without rElGH immersion (control. Each treatment was performed in triplicates. Immersion was performed for 3 hours, at 4-day intervals and a density of 100 tropical abalones in 1 L seawater containing 30

Involvement of Antizyme Characterized from the Small Abalone Haliotis diversicolor in Gonadal Development.

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Li, Wei-Dong; Huang, Min; Lü, Wen-Gang; Chen, Xiao; Shen, Ming-Hui; Li, Xiang-Min; Wang, Rong-Xia; Ke, Cai-Huan

2015-01-01

The small abalone Haliotis diversicolor is an economically important mollusk that is widely cultivated in Southern China. Gonad precocity may affect the aquaculture of small abalone. Polyamines, which are small cationic molecules essential for cellular proliferation, may affect gonadal development. Ornithine decarboxylase (ODC) and antizyme (AZ) are essential elements of a feedback circuit that regulates cellular polyamines. This paper presents the molecular cloning and characterization of AZ from small abalone. Sequence analysis showed that the cDNA sequence of H. diversicolor AZ (HdiODCAZ) consisted of two overlapping open reading frames (ORFs) and conformed to the +1 frameshift property of the frame. Thin Layer chromatography (TLC) analysis suggested that the expressed protein encoded by +1 ORF2 was the functional AZ that targets ODC to 26S proteasome degradation. The result demonstrated that the expression level of AZ was higher than that of ODC in the ovary of small abalone. In addition, the expression profiles of ODC and AZ at the different development stages of the ovary indicated that these two genes might be involved in the gonadal development of small abalone.

Vibrio harveyi Adheres to and Penetrates Tissues of the European Abalone Haliotis tuberculata within the First Hours of Contact

OpenAIRE

Cardinaud, Marion; Barbou, Annaïck; Capitaine, Carole; Bidault, Adeline; Dujon, Antoine Marie; Moraga, Dario; Paillard, Christine

2014-01-01

International audience; Vibrio harveyi is a marine bacterial pathogen responsible for episodic epidemics generally associated with massive mortalities in many marine organisms, including the European abalone Haliotis tuberculata. The aim of this study was to identify the portal of entry and the dynamics of infection of V. harveyi in the European abalone. The results indicate that the duration of contact be-tween V. harveyi and the European abalone influences the mortality rate and precocity. ...

Characterization of defensin gene from abalone Haliotis discus hannai and its deduced protein

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Hong, Xuguang; Sun, Xiuqin; Zheng, Minggang; Qu, Lingyun; Zan, Jindong; Zhang, Jinxing

2008-11-01

Defensin is one of preserved ancient host defensive materials formed in biological evolution. As a regulator and effector molecule, it is very important in animals’ acquired immune system. This paper reports the defensin gene from the mixed liver and kidney cDNA library of abalone Haliotis discus hannai Ino. Sequence analysis shows that the gene sequence of full-length cDNA encodes 42 mature peptides (including six Cys), molecular weight of 4 323 Da, and pI of 8.02. Amino acid sequence homology analysis shows that the peptides are highly similar (70% in common) to other insects defensin. Because of a typical insect-defensin structural character of mature peptide in the secondary structure, the polypeptide named Haliotis discus defensin (hd-def), a novel of antimicrobial peptides, belongs to insects defensin subfamily. The RT-PCR result of Haliotis discus defensin shows that the gene can be expressed only in the hepatopancreas by Gram-negative and positive bacteria stimulation, which is ascribed to inducible expression. Therefore, it is revealed that the Haliotis discus defensin gene expression was related to the antibacterial infection of Haliotis discus hannai Ino.

Molecular characterization of kappa class glutathione S-transferase from the disk abalone (Haliotis discus discus) and changes in expression following immune and stress challenges.

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Sandamalika, W M Gayashani; Priyathilaka, Thanthrige Thiunuwan; Liyanage, D S; Lee, Sukkyoung; Lim, Han-Kyu; Lee, Jehee

2018-06-01

Glutathione S-transferase (GST; EC 2.5.1.18) isoenzymes represent a complex group of proteins that are involved in phase II detoxification in several organisms. In this study, GST kappa (GSTκ) from the disk abalone (Haliotis discus discus; AbGSTκ) was characterized at both the transcriptional and functional levels to determine its potential capacity to perform as a detoxification agent under conditions of different stress. The predicted AbGSTκ protein consists of 227 amino acids, with a predicted molecular weight of 25.6 kDa and a theoretical isoelectric point (pI) of 7.78. In silico analysis reveals that AbGSTκ is a disulfide bond formation protein A (DsbA), consisting of a thioredoxin domain, GSH binding sites (G-sites), and a catalytic residue. In contrast, no hydrophobic ligand binding site (H-site), or signal peptides, were detected. AbGSTκ showed the highest sequence identity with the orthologue from pufferfish (Takifugu obscurus) (60.0%). In a phylogenetic tree, AbGSTκ clustered closely together with other fish GSTκs, and was evolutionarily distanced from other cytosolic GSTs. The predicted three-dimensional structure clearly demonstrates that the dimer adopts a butterfly-like shape. A tissue distribution analysis revealed that GSTκ was highly expressed in the digestive tract, suggesting it has detoxification ability. Depending on the tissue and time, AbGSTκ showed different expression patterns, and levels of expression, following challenge of the abalone with immune stimulants. Enzyme kinetics of the purified recombinant proteins demonstrated its conjugating ability using 1-Chloro-2,4-dinitrobenzene (CDNB) and glutathione (GSH) as substrates, and suggested it has a low affinity for both substrates. The optimum temperature and pH for the rAbGSTκ GSH: CDNB conjugating activity were found to be 35 °C and pH 8, respectively indicating that the abalone is well adapted to a wide range of environmental conditions. Cibacron blue (100 μM) was

Genetic diversity and stock identification of small abalone (Haliotis diversicolor) in Taiwan and Japan.

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Hsu, Te-Hua; Gwo, Jin-Chywan

2017-01-01

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

Involvement of Antizyme Characterized from the Small Abalone Haliotis diversicolor in Gonadal Development.

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Wei-Dong Li

Full Text Available The small abalone Haliotis diversicolor is an economically important mollusk that is widely cultivated in Southern China. Gonad precocity may affect the aquaculture of small abalone. Polyamines, which are small cationic molecules essential for cellular proliferation, may affect gonadal development. Ornithine decarboxylase (ODC and antizyme (AZ are essential elements of a feedback circuit that regulates cellular polyamines. This paper presents the molecular cloning and characterization of AZ from small abalone. Sequence analysis showed that the cDNA sequence of H. diversicolor AZ (HdiODCAZ consisted of two overlapping open reading frames (ORFs and conformed to the +1 frameshift property of the frame. Thin Layer chromatography (TLC analysis suggested that the expressed protein encoded by +1 ORF2 was the functional AZ that targets ODC to 26S proteasome degradation. The result demonstrated that the expression level of AZ was higher than that of ODC in the ovary of small abalone. In addition, the expression profiles of ODC and AZ at the different development stages of the ovary indicated that these two genes might be involved in the gonadal development of small abalone.

KERAGAAN PERTUMBUHAN DAN VARIASI GENETIK ABALON Haliotis squamata Reeve (1846 HASIL SELEKSI F-1

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Gusti Ngurah Permana

2015-12-01

Full Text Available Produksi benih abalon Haliotis squamata skala massal di hatcheri telah berhasil dilakukan di Balai Besar Penelitian dan Pengembangan Budidaya Laut Gondol, Bali. Permasalahan utama dalam budidaya abalon adalah pertumbuhan yang lambat. Keadaan tersebut diduga karena pengaruh faktor genetik dan lingkungan. Penelitian ini bertujuan mengetahui keragaan pertumbuhan dan variasi genetik abalon tumbuh cepat hasil seleksi individu. Hasil penelitian ini diketahui bahwa pembentukan populasi F-1 mempunyai pertumbuhan yang lebih baik dengan F-1 kontrol. Peningkatan bobot yang dicapai 22,15 g atau 17,93% lebih baik dibandingkan F-1 kontrol. Keragaman genetik F-1 terseleksi yang ditunjukkan dari nilai heterozigositas adalah (Ho. 0,023 terjadi penurunan 21,7% jika dibandingkan F-0. Hal ini dapat terjadi karena hilangnya beberapa allele dalam proses seleksi. Terdapat hubungan antara jumlah heterozigot pada lokus tertentu dengan pertumbuhan abalon. Hasil ini diharapkan dapat mendukung upaya meningkatkan produksi benih yang mempunyai performa fenotipe dan genotipe unggul sehingga dapat mendukung kegiatan budidaya abalon yang berkelanjutan.

Transcriptome characterization of the South African abalone Haliotis midae using sequencing-by-synthesis

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Roodt-Wilding Rouvay

2011-03-01

Full Text Available Abstract Background Worldwide, the genus Haliotis is represented by 56 extant species and several of these are commercially cultured. Among the six abalone species found in South Africa, Haliotis midae is the only aquacultured species. Despite its economic importance, genomic sequence resources for H. midae, and for abalone in general, are still scarce. Next generation sequencing technologies provide a fast and efficient tool to generate large sequence collections that can be used to characterize the transcriptome and identify expressed genes associated with economically important traits like growth and disease resistance. Results More than 25 million short reads generated by the Illumina Genome Analyzer were de novo assembled in 22,761 contigs with an average size of 260 bp. With a stringent E-value threshold of 10-10, 3,841 contigs (16.8% had a BLAST homologous match against the Genbank non-redundant (NR protein database. Most of these sequences were annotated using the gene ontology (GO and eukaryotic orthologous groups of proteins (KOG databases and assigned to various functional categories. According to annotation results, many gene families involved in immune response were identified. Thousands of simple sequence repeats (SSR and single nucleotide polymorphisms (SNP were detected. Setting stringent parameters to ensure a high probability of amplification, 420 primer pairs in 181 contigs containing SSR loci were designed. Conclusion This data represents the most comprehensive genomic resource for the South African abalone H. midae to date. The amount of assembled sequences demonstrated the utility of the Illumina sequencing technology in the transcriptome characterization of a non-model species. It allowed the development of several markers and the identification of promising candidate genes for future studies on population and functional genomics in H. midae and in other abalone species.

The cross-tissue metabolic response of abalone (Haliotis midae) to functional hypoxia.

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Venter, Leonie; Loots, Du Toit; Mienie, Lodewyk J; Jansen van Rensburg, Peet J; Mason, Shayne; Vosloo, Andre; Lindeque, Jeremie Z

2018-03-23

Functional hypoxia is a stress condition caused by the abalone itself as a result of increased muscle activity, which generally necessitates the employment of anaerobic metabolism if the activity is sustained for prolonged periods. With that being said, abalone are highly reliant on anaerobic metabolism to provide partial compensation for energy production during oxygen-deprived episodes. However, current knowledge on the holistic metabolic response for energy metabolism during functional hypoxia, and the contribution of different metabolic pathways and various abalone tissues towards the overall accumulation of anaerobic end-products in abalone are scarce. Metabolomics analysis of adductor muscle, foot muscle, left gill, right gill, haemolymph and epipodial tissue samples indicated that South African abalone ( Haliotis midae) subjected to functional hypoxia utilises predominantly anaerobic metabolism, and depends on all of the main metabolite classes (proteins, carbohydrates and lipids) for energy supply. Functional hypoxia caused increased levels of anaerobic end-products: lactate, alanopine, tauropine, succinate and alanine. Also, elevation in arginine levels was detected, confirming that abalone use phosphoarginine to generate energy during functional hypoxia. Different tissues showed varied metabolic responses to hypoxia, with functional hypoxia showing excessive changes in the adductor muscle and gills. From this metabolomics investigation, it becomes evident that abalone are metabolically able to produce sufficient amounts of energy when functional hypoxia is experienced. Also, tissue interplay enables the adjustment of H. midae energy requirements as their metabolism shifts from aerobic to anaerobic respiration during functional hypoxia.This article has an associated First Person interview with the first author of the paper. © 2018. Published by The Company of Biologists Ltd.

The cross-tissue metabolic response of abalone (Haliotis midae to functional hypoxia

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Leonie Venter

2018-03-01

Full Text Available Functional hypoxia is a stress condition caused by the abalone itself as a result of increased muscle activity, which generally necessitates the employment of anaerobic metabolism if the activity is sustained for prolonged periods. With that being said, abalone are highly reliant on anaerobic metabolism to provide partial compensation for energy production during oxygen-deprived episodes. However, current knowledge on the holistic metabolic response for energy metabolism during functional hypoxia, and the contribution of different metabolic pathways and various abalone tissues towards the overall accumulation of anaerobic end-products in abalone are scarce. Metabolomics analysis of adductor muscle, foot muscle, left gill, right gill, haemolymph and epipodial tissue samples indicated that South African abalone (Haliotis midae subjected to functional hypoxia utilises predominantly anaerobic metabolism, and depends on all of the main metabolite classes (proteins, carbohydrates and lipids for energy supply. Functional hypoxia caused increased levels of anaerobic end-products: lactate, alanopine, tauropine, succinate and alanine. Also, elevation in arginine levels was detected, confirming that abalone use phosphoarginine to generate energy during functional hypoxia. Different tissues showed varied metabolic responses to hypoxia, with functional hypoxia showing excessive changes in the adductor muscle and gills. From this metabolomics investigation, it becomes evident that abalone are metabolically able to produce sufficient amounts of energy when functional hypoxia is experienced. Also, tissue interplay enables the adjustment of H. midae energy requirements as their metabolism shifts from aerobic to anaerobic respiration during functional hypoxia. This article has an associated First Person interview with the first author of the paper.

Molecular identification and functional delineation of a glutathione reductase homolog from disk abalone (Haliotis discus discus): Insights as a potent player in host antioxidant defense.

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Herath, H M L P B; Wickramasinghe, P D S U; Bathige, S D N K; Jayasooriya, R G P T; Kim, Gi-Young; Park, Myoung Ae; Kim, Chul; Lee, Jehee

2017-01-01

Glutathione reductase (GSR) is an enzyme that catalyzes the biochemical conversion of oxidized glutathione (GSSG) into the reduced form (GSH). Since the ratio between the two forms of glutathione (GSH/GSSG) is important for the optimal function of GSH to act as an antioxidant against H 2 O 2 , the contribution of GSR as an enzymatic regulatory agent to maintain the proper ratio is essential. Abalones are marine mollusks that frequently encounter environmental factors that can trigger the overproduction of reactive oxygen species (ROS) such as H 2 O 2 . Therefore, we conducted the current study to reveal the molecular and functional properties of a GSR homolog in the disk abalone, Haliotis discus discus. The identified cDNA sequence (2325 bp) has a 1356 bp long open reading frame (ORF), coding for a 909 bp long amino acid sequence, which harbors a pyridine nucleotide-disulfide oxidoreductase domain (171-246 aa), a pyridine nucleotide-disulfide oxidoreductase dimerization domain, and a NAD(P)(+)-binding Rossmann fold superfamily signature domain. Four functional residues: the FAD binding site, glutathione binding site, NADPH binding motif, and assembly domain were identified to be conserved among the other species. The recombinant abalone GSR (rAbGSR) exhibited detectable activity in a standard glutathione reductase activity assay. The optimum pH and optimal temperature for the reaction were found to be 7.0 and 50 °C, respectively, while the ionic strength of the medium had no effect. The enzymatic reaction was vastly inhibited by Cu +2 and Cd +2 ions. A considerable effect of cellular protection was detected with a disk diffusion assay conducted with rAbGSR. Moreover, an MTT assay and flow cytometry confirmed the significance of the protective role of rAbGSR in cell function. Furthermore, AbGSR was found to be ubiquitously distributed in different types of abalone tissues. AbGSR mRNA expression was significantly upregulated in response to three immune challenges

Genetic differentiation between fake abalone and genuine Haliotis species using the forensically informative nucleotide sequencing (FINS) method.

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Ha, Wai Y; Reid, David G; Kam, Wan L; Lau, Yuk Y; Sham, Wing C; Tam, Silvia Y K; Sin, Della W M; Mok, Chuen S

2011-05-25

Abalones ( Haliotis species) are a popular delicacy and commonly preserved in dried form either whole or in slices or small pieces for consumption in Asian countries. Driven by the huge profit from trading abalones, dishonest traders may substitute other molluscan species for processed abalone, of which the morphological characteristics are frequently lost in the processed form. For protection of consumer rights and law enforcement against fraud, there is a need for an effective methodology to differentiate between fake and genuine abalone. This paper describes a method (validated according to the international forensic guidelines provided by SWGDAM) for the identification of fake abalone species using forensically informative nucleotide sequence (FINS) analysis. A study of the local market revealed that many claimed "abalone slice" samples on sale are not genuine. The fake abalone samples were found to be either volutids of the genus Cymbium (93%) or the muricid Concholepas concholepas (7%). This is the first report of Cymbium species being used for the preparation and sale as "abalone" in dried sliced form in Hong Kong.

Identification and characterization of miRNAs transcriptome in the South African abalone, Haliotis midae.

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Picone, Barbara; Rhode, Clint; Roodt-Wilding, Rouvay

2017-02-01

Aquatic animal diseases are one of the most important limitations to the growth of aquaculture. miRNAs represent an important class of small ncRNAs able to modulate host immune and stress responses. In Mollusca, a large phylum of invertebrates, miRNAs have been identified in several species. The current preliminary study identified known miRNAs from the South African abalone, Haliotis midae. The economic and ecological importance of abalone makes this species a suitable model for studying and understanding stress response in marine gastropods. Furthermore, the identification of miRNA, represents an alternative and powerful tool to combat infectious disease. Copyright © 2016 Elsevier B.V. All rights reserved.

Genome sequence of pacific abalone (Haliotis discus hannai): the first draft genome in family Haliotidae.

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Nam, Bo-Hye; Kwak, Woori; Kim, Young-Ok; Kim, Dong-Gyun; Kong, Hee Jeong; Kim, Woo-Jin; Kang, Jeong-Ha; Park, Jung Youn; An, Cheul Min; Moon, Ji-Young; Park, Choul Ji; Yu, Jae Woong; Yoon, Joon; Seo, Minseok; Kim, Kwondo; Kim, Duk Kyung; Lee, SaetByeol; Sung, Samsun; Lee, Chul; Shin, Younhee; Jung, Myunghee; Kang, Byeong-Chul; Shin, Ga-Hee; Ka, Sojeong; Caetano-Anolles, Kelsey; Cho, Seoae; Kim, Heebal

2017-05-01

Abalones are large marine snails in the family Haliotidae and the genus Haliotis belonging to the class Gastropoda of the phylum Mollusca. The family Haliotidae contains only one genus, Haliotis, and this single genus is known to contain several species of abalone. With 18 additional subspecies, the most comprehensive treatment of Haliotidae considers 56 species valid [ 1 ]. Abalone is an economically important fishery and aquaculture animal that is considered a highly prized seafood delicacy. The total global supply of abalone has increased 5-fold since the 1970s and farm production increased explosively from 50 mt to 103 464 mt in the past 40 years. Additionally, researchers have recently focused on abalone given their reported tumor suppression effect. However, despite the valuable features of this marine animal, no genomic information is available for the Haliotidae family and related research is still limited. To construct the H . discus hannai genome, a total of 580-G base pairs using Illumina and Pacbio platforms were generated with 322-fold coverage based on the 1.8-Gb estimated genome size of H . discus hannai using flow cytometry. The final genome assembly consisted of 1.86 Gb with 35 450 scaffolds (>2 kb). GC content level was 40.51%, and the N50 length of assembled scaffolds was 211 kb. We identified 29 449 genes using Evidence Modeler based on the gene information from ab initio prediction, protein homology with known genes, and transcriptome evidence of RNA-seq. Here we present the first Haliotidae genome, H . discus hannai , with sequencing data, assembly, and gene annotation information. This will be helpful for resolving the lack of genomic information in the Haliotidae family as well as providing more opportunities for understanding gastropod evolution. © The Authors 2017. Published by Oxford University Press.

Effects of dietary carbohydrates sources on lipids compositions in abalone, Haliotis discus hannai Ino

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Wang, Weifang; Mai, Kangsen; Zhang, Wenbing; Xu, Wei; Ai, Qinghui; Yao, Chunfeng; Li, Huitao

2009-09-01

A study was conducted to evaluate the effects of dietary carbohydrates on triglyceride, cholesterol and fatty acid concentrations in abalone, Haliotis discus hannai Ino. Six semi-purified diets with different carbohydrates (dextrin, heat-treated wheat starch, wheat starch, corn starch, tapioca starch and potato starch, respectively), all containing a carbohydrate level of 33.5%, were fed to abalone (initial shell length: 29.98 mm ± 0.09 mm; initial weight: 3.42 g ± 0.02 g) for 24 weeks in a recirculation system. The results indicate that serum triglyceride concentrations were significantly ( P abalone fed with dextrin, heat-treated wheat starch and wheat starch than those fed with corn starch, and serum cholesterol concentrations were significantly ( P abalone fed with dextrin, heat-treated wheat starch than those fed with corn starch. Fatty acid C20:4n-6 in the foot muscles were significantly ( P abalone fed with dextrin than those fed with wheat starch, corn starch, tapioca starch and potato starch. Fatty acid C20:4n-6 in hepatopancreas was significantly ( P abalone fed with heat-treated wheat starch than those fed with corn starch, tapioca starch and potato starch. Fatty acid C22:6n-3 in the foot muscles were significantly ( P abalone fed with dextrin and heat-treated wheat starch than those fed with wheat starch and potato starch.

Identification and characterization of Vibrio harveyi associated with diseased abalone Haliotis diversicolor.

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Jiang, Qingru; Shi, Liuyang; Ke, Caihuan; You, Weiwei; Zhao, Jing

2013-03-26

Mass mortality of farmed small abalone Haliotis diversicolor occurred in Fujian, China, from 2009 to 2011. Among isolates obtained from moribund abalones, the dominant species AP37 exhibited the strongest virulence. After immersion challenge with 106 CFU ml-1 of AP37, abalone mortalities of 0, 53 and 67% were induced at water temperatures of 20°C, 24°C, and 28°C, respectively. Following intramuscular injection, AP37 showed a low LD50 (median lethal concentration) value of 2.9 × 102 CFU g-1 (colony forming units per gram abalone wet body weight). The LT50 (median lethal time) values were 5.2 h for 1 × 106 CFU abalone-1, 8.4 h for 1 × 105 CFU abalone-1, and 21.5 h for 1 × 104 CFU abalone-1. For further analysis of virulence, AP37 was screened for the production of extracellular factors. The results showed that various factors including presence of flagella and production of extracellular enzymes, such as lipase, phospholipase and haemolysin, could be responsible for pathogenesis. Based on its 16S rRNA gene sequence, strain AP37 showed >98.8% similarity to Vibrio harveyi, V. campbellii, V. parahaemolyticus, V. alginolyticus, V. natriegens and V. rotiferianus, so it could not be identified by this method. However, multi-locus sequence analysis (MLSA) of concatenated sequences, including the rpoD, rctB, gyrB, toxR and pyrH genes, identified strain AP37 as V. harveyi. Phenotypic characters of AP37 were identified by API 20E. In antibiotic susceptibility tests, strain AP37 exhibited susceptibility to 7 antibiotics and resistance to 13. This is the first report of a V. harveyi-related species being linked with the mass mortality of adult abalone H. diversicolor in southern China.

Identification of a female spawn-associated Kazal-type inhibitor from the tropical abalone Haliotis asinina.

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Wang, Tianfang; Nuurai, Parinyaporn; McDougall, Carmel; York, Patrick S; Bose, Utpal; Degnan, Bernard M; Cummins, Scott F

2016-07-01

Abalone (Haliotis) undergoes a period of reproductive maturation, followed by the synchronous release of gametes, called broadcast spawning. Field and laboratory studies have shown that the tropical species Haliotis asinina undergoes a two-week spawning cycle, thus providing an excellent opportunity to investigate the presence of endogenous spawning-associated peptides. In female H. asinina, we have isolated a peptide (5145 Da) whose relative abundance in hemolymph increases substantially just prior to spawning and is still detected using reverse-phase high-performance liquid chromatography chromatograms up to 1-day post-spawn. We have isolated this peptide from female hemolymph as well as samples prepared from the gravid female gonad, and demonstrated through comparative sequence analysis that it contains features characteristic of Kazal-type proteinase inhibitors (KPIs). Has-KPI is expressed specifically within the gonad of adult females. A recombinant Has-KPI was generated using a yeast expression system. The recombinant Has-KPI does not induce premature spawning of female H. asinina when administered intramuscularly. However it displays homomeric aggregations and interaction with at least one mollusc-type neuropeptide (LRDFVamide), suggesting a role for it in regulating neuropeptide endocrine communication. This research provides new understanding of a peptide that can regulate reproductive processes in female abalone, which has the potential to lead to the development of greater control over abalone spawning. The findings also highlight the need to further explore abalone reproduction to clearly define a role for novel spawning-associated peptide in sexual maturation and spawning. Copyright © 2016 European Peptide Society and John Wiley & Sons, Ltd. Copyright © 2016 European Peptide Society and John Wiley & Sons, Ltd.

PI3K-AKT signaling pathway is involved in hypoxia/thermal-induced immunosuppression of small abalone Haliotis diversicolor.

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Sun, Yulong; Zhang, Xin; Wang, Guodong; Lin, Shi; Zeng, Xinyang; Wang, Yilei; Zhang, Ziping

2016-12-01

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 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. Copyright © 2016 Elsevier Ltd. All rights reserved.

KARAKTERISASI DAN EVALUASI POPULASI ABALON Haliotis squamata SECARA MOLEKULER, MORFOMETRIK, DAN BIOLOGI

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Gusti Ngurah Permana

2017-10-01

Full Text Available Abalon merupakan salah satu komoditas penting gastropoda laut. Tingginya permintaan abalon ini mengakibatkan menipisnya stok di alam. Oleh karena itu, upaya keberhasilan budidaya abalon perlu didukung oleh jenis unggul. Indikasi awal suatu jenis unggul dapat dilakukan dengan menganalisis potensi genetik yang dimiliki. Penelitian ini dilakukan dengan analisis gen 16S rRNA, karakter morfolologi, dan biologi dianalisis secara deskriptif dengan metode kajian pustaka. Hasil yang diperoleh menunjukkan keragaman inter populasi Haliotis squamata mendeteksi adanya tujuh haplotipe yang terbagi dalam dua kelompok. Penyertaan H. diversicolor sebagai outgroup dalam pengujian memperlihatkan bahwa populasi H. squamata dari Pulau Bali dan beberapa lokasi di Pulau Jawa berada dalam satu kelompok yang terpisah dengan outgroup. Hasil ini kongruen dengan analisis morfometrik terdapat perkembangan pertumbuhan cangkang yang asimetri pada populasi Banten. Pertumbuhan asimetri merupakan indikasi spesifik untuk populasi Banten atau merupakan gejala abnormalitas yang dapat diakibatkan oleh faktor penurunan kualitas genetik atau lingkungan. Karakter biologi terlihat proporsi daging dan gonad berbeda pada populasi Banten dengan indikasi adanya pertumbuhan asimetri. Rasio gonad dan daging populasi Banyuwangi berbeda nyata (P<0,05 dengan populasi lainnya. Abalone is arguably one of the highly valued and sought-after marine gastropods. However, the over-exploitation of this species has exhausted its wild stock. To overcome this challenge, the culture technique and management of this species must be established and continually improved. One of the ways is through producing superior broodstocks. An initial assessment of a genetically superior broodstock can be done using the potential genetic analysis. This recent research employed the analysis to study the species’ 16S rRNA gene. To complement the study, the morphometric and biological characteristics of the species were

Probabilistic risk assessment of abalone Haliotis diversicolor supertexta exposed to waterborne zinc

International Nuclear Information System (INIS)

Liao Chungmin; Ling Minpei

2004-01-01

This paper describes a risk assessment approach that integrates predicted tissue concentrations of zinc (Zn) with a concentration-response relationship and leads to predictions of survival risk for pond abalone Haliotis diversicolor supertexta as well as to the uncertainties associated with these predictions. The models implemented include a probabilistic bioaccumulation model, which linking biokinetic and consumer-resource models, accounts for Zn exposure profile and a modified Hill model for reconstructing a dose-response profile for abalone exposed to waterborne Zn. The growth risk is assessed by hazard quotients characterized by measured water level and chronic no-observed effect concentration. Our risk analyses for H. diversicolor supertexta reared near Toucheng, Kouhu, and Anping, respectively, in north, central, and south Taiwan region indicate a relatively low likelihood that survival is being affected by waterborne Zn. Expected risks of mortality for abalone were estimated as 0.46 (Toucheng), 0.36 (Kouhu), and 0.29 (Anping). The predicted 90th-percentiles of hazard quotient for potential growth risk were estimated as 1.94 (Toucheng), 0.47 (Kouhu), and 0.51 (Anping). These findings indicate that waterborne Zn exposure poses no significant risk to pond abalone in Kouhu and Anping, yet a relative high growth risk in Toucheng is alarming. Because of a scarcity of toxicity and exposure data, the probabilistic risk assessment was based on very conservative assumptions. - A novel risk assessment method was developed for abalone

Probabilistic risk assessment of abalone Haliotis diversicolor supertexta exposed to waterborne zinc

Energy Technology Data Exchange (ETDEWEB)

Liao Chungmin; Ling Minpei

2004-01-01

This paper describes a risk assessment approach that integrates predicted tissue concentrations of zinc (Zn) with a concentration-response relationship and leads to predictions of survival risk for pond abalone Haliotis diversicolor supertexta as well as to the uncertainties associated with these predictions. The models implemented include a probabilistic bioaccumulation model, which linking biokinetic and consumer-resource models, accounts for Zn exposure profile and a modified Hill model for reconstructing a dose-response profile for abalone exposed to waterborne Zn. The growth risk is assessed by hazard quotients characterized by measured water level and chronic no-observed effect concentration. Our risk analyses for H. diversicolor supertexta reared near Toucheng, Kouhu, and Anping, respectively, in north, central, and south Taiwan region indicate a relatively low likelihood that survival is being affected by waterborne Zn. Expected risks of mortality for abalone were estimated as 0.46 (Toucheng), 0.36 (Kouhu), and 0.29 (Anping). The predicted 90th-percentiles of hazard quotient for potential growth risk were estimated as 1.94 (Toucheng), 0.47 (Kouhu), and 0.51 (Anping). These findings indicate that waterborne Zn exposure poses no significant risk to pond abalone in Kouhu and Anping, yet a relative high growth risk in Toucheng is alarming. Because of a scarcity of toxicity and exposure data, the probabilistic risk assessment was based on very conservative assumptions. - A novel risk assessment method was developed for abalone.

Characterization of genic microsatellite markers derived from expressed sequence tags in Pacific abalone ( Haliotis discus hannai)

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Li, Qi; Shu, Jing; Zhao, Cui; Liu, Shikai; Kong, Lingfeng; Zheng, Xiaodong

2010-01-01

Simple sequence repeat (SSR) markers were developed from the expressed sequence tags (ESTs) of Pacific abalone ( Haliotis discus hannai). Repeat motifs were found in 4.95% of the ESTs at a frequency of one repeat every 10.04 kb of EST sequences, after redundancy elimination. Seventeen polymorphic EST-SSRs were developed. The number of alleles per locus varied from 2-17, with an average of 6.8 alleles per locus. The expected and observed heterozygosities ranged from 0.159 to 0.928 and from 0.132 to 0.922, respectively. Twelve of the 17 loci (70.6%) were successfully amplified in H. diversicolor. Seventeen loci segregated in three families, with three showing the presence of null alleles (17.6%). The adequate level of variability and low frequency of null alleles observed in H. discus hannai, together with the high rate of transportability across Haliotis species, make this set of EST-SSR markers an important tool for comparative mapping, marker-assisted selection, and evolutionary studies, not only in the Pacific abalone, but also in related species.

In vitro anti-thrombotic and anti-coagulant properties of blacklip abalone (Haliotis rubra) viscera hydrolysate.

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Suleria, Hafiz Ansar Rasul; Masci, Paul P; Addepalli, Rama; Chen, Wei; Gobe, Glenda C; Osborne, Simone A

2017-07-01

Abalone viscera contain sulphated polysaccharides with anti-thrombotic and anti-coagulant activities. In this study, a hydrolysate was prepared from blacklip abalone (Haliotis rubra) viscera using papain and bromelain and fractionated using ion exchange and size exclusion chromatography. Hydrolysates and fractions were investigated for in vitro thrombin inhibition mediated through heparin cofactor II (HCII) as well as anti-coagulant activity in plasma and whole blood. On the basis of sulphated polysaccharide concentration, the hydrolysate inhibited thrombin through HCII with an inhibitor concentration at 50% (IC50) of 16.5 μg/mL compared with 2.1 μg/mL for standard heparin. Fractionation concentrated HCII-mediated thrombin inhibition down to an IC50 of 1.8 μg/mL and improved anti-coagulant activities by significantly delaying clotting time. This study confirmed the presence of anti-thrombotic and anti-coagulant molecules in blacklip abalone viscera and demonstrated that these activities can be enriched with a simple chromatography regime. Blacklip abalone viscera warrant further investigation as a source of nutraceutical or functional food ingredients. Graphical abstract Schematic showing preparation of bioactive extracts and fractions from blacklip abalone.

Genomic characterization and expression profiles upon bacterial infection of a novel cystatin B homologue from disk abalone (Haliotis discus discus).

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Premachandra, H K A; Wan, Qiang; Elvitigala, Don Anushka Sandaruwan; De Zoysa, Mahanama; Choi, Cheol Young; Whang, Ilson; Lee, Jehee

2012-12-01

Cystatins are a large family of cysteine proteinase inhibitors which are involved in diverse biological and pathological processes. In the present study, we identified a gene related to cystatin superfamily, AbCyt B, from disk abalone Haliotis discus discus by expressed sequence tag (EST) analysis and BAC library screening. The complete cDNA sequence of AbCyt B is comprised of 1967 nucleotides with a 306 bp open reading frame (ORF) encoding for 101 amino acids. The amino acid sequence consists of a single cystatin-like domain, which has a cysteine proteinase inhibitor signature, a conserved Gly in N-terminal region, QVVAG motif and a variant of PW motif. No signal peptide, disulfide bonds or carbohydrate side chains were identified. Analysis of deduced amino acid sequence revealed that AbCyt B shares up to 44.7% identity and 65.7% similarity with the cystatin B genes from other organisms. The genomic sequence of AbCyt B is approximately 8.4 Kb, consisting of three exons and two introns. Phylogenetic tree analysis showed that AbCyt B was closely related to the cystatin B from pacific oyster (Crassostrea gigas) under the family 1.Functional analysis of recombinant AbCyt B protein exhibited inhibitory activity against the papain, with almost 84% inhibition at a concentration of 3.5 μmol/L. In tissue expression analysis, AbCyt B transcripts were expressed abundantly in the hemocyte, gill, mantle, and digestive tract, while weakly in muscle, testis, and hepatopancreas. After the immune challenge with Vibrio parahemolyticus, the AbCyt B showed significant (P<0.05) up-regulation of relative mRNA expression in gill and hemocytes at 24 and 6 h of post infection, respectively. These results collectively suggest that AbCyst B is a potent inhibitor of cysteine proteinases and is also potentially involved in immune responses against invading bacterial pathogens in abalone. Copyright © 2012 Elsevier Ltd. All rights reserved.

Effects of dietary menadione on the activity of antioxidant enzymes in abalone, Haliotis discus hannai Ino

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Fu, Jinghua; Xu, Wei; Mai, Kangsen; Zhang, Wenbing; Feng, Xiuni; Liufu, Zhiguo

2012-01-01

A 240-day growth experiment in a re-circulating water system was conducted to investigate the effects of dietary menadione on the growth and antioxidant responses of abalone Haliotis discus hannai Ino. Triplicate groups of juvenile abalone (initial weight: 1.19 ± 0.01 g; shell length: 19.23 ± 0.01 mm) were fed to satiation with 3 semi-purified diets containing 0, 10, and 1 000 mg menadione sodium bisulfite (MSB)/kg, respectively. Results show that there were no significant differences in the rate of weight gain or in the daily increment in shell length of abalone among different treatments. Activities of superoxide dismutase (SOD), glutathione peroxidase (GPX), glutathione S-transferase (GST) and glutathione reductase (GR) in viscera were significantly decreased with dietary menadione. However, activities of these enzymes except for GPX in muscle were increased. Therefore, antioxidant responses of abalone were increased in muscle and decreased in viscera by dietary menadione.

De novo characterisation of the greenlip abalone transcriptome (Haliotis laevigata) with a focus on the heat shock protein 70 (HSP70) family.

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Shiel, Brett P; Hall, Nathan E; Cooke, Ira R; Robinson, Nicholas A; Strugnell, Jan M

2015-02-01

Abalone (Haliotis) are economically important molluscs for fisheries and aquaculture industries worldwide. Despite this, genomic resources for abalone and molluscs are still limited. Here we present a description and functional annotation of the greenlip abalone (Haliotis laevigata) transcriptome. We present a focused analysis on the heat shock protein 70 (HSP70) family of genes with putative functions affecting temperature stress and immunity. A total of ~38 million paired end Illumina reads were obtained, resulting in a Trinity assembly of 222,172 contigs with minimum length of 200 base pairs and maximum length of 33 kilobases. The 20,702 contigs were annotated with gene descriptions by BLAST. We created a program to maximise the number of functionally annotated genes, and over 10,000 contigs were assigned Gene ontologies (GO terms). By using CateGOrizer, immunity related GO terms for stressors such as heat, hypoxia, oxidative stress and wounding received the highest counts. Twenty-six contigs with homology to the HSP70 family of genes were identified. Ninety-one putative single-nucleotide polymorphisms were observed in the abalone HSP70 contigs. Eleven of these were considered non-synonymous. The annotated transcriptome described in this study will be a useful basis for future work investigating the genetic response of abalone to stress.

Diatom diet selectivity by early post-larval abalone Haliotis diversicolor supertexta under hatchery conditions

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Zhang, Yuyu; Gao, Yahui; Liang, Junrong; Chen, Changping; Zhao, Donghai; Li, Xuesong; Li, Yang; Wu, Wenzhong

2010-11-01

Benthic diatoms constitute the primary diet of abalone during their early stages of development. To evaluate the dietary preferences of early post-larval abalone, Haliotis diversicolor supertexta, we analyzed the gut contents of post-larvae that settled on diatom films. We compared the abundance and species diversity of diatom assemblages in the gut to those of the epiphytic diatom assemblages on the attachment films, and identified 40 benthic diatom species in the gut contents of post-larvae 12 to 24 d after settlement. The most abundant taxa in the gut contents were Navicula spp., Amphora copulate, and Amphora coffeaeformis. Navicula spp. accounted for 64.0% of the cell density. In the attachment films, we identified 110 diatom species belonging to 38 genera. Pennate diatoms were the dominant members including the species Amphiprora alata, Cocconeis placentula var. euglypta, Cylindrotheca closterium, Navicula sp. 2, and A. coffeaeformis. Nano-diatoms (abalone seed. The difference of the composition and abundance of diatoms between in the guts and on the biofilms suggests that early post-larval grazing was selective. An early post-larval abalone preferred nano-diatoms and the genera Navicula and Amphora during the month after settlement.

Preparation, characterisation and use for antioxidant oligosaccharides of a cellulase from abalone (Haliotis discus hannai) viscera.

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Tao, Zhi-Peng; Sun, Le-Chang; Qiu, Xu-Jian; Cai, Qiu-Feng; Liu, Guang-Ming; Su, Wen-Jin; Cao, Min-Jie

2016-07-01

In China, abalone (Haliotis discus hannai) production is growing annually. During industrial processing, the viscera, which are abundant of cellulase, are usually discarded or processed into low-value feedstuff. Thus, it is of interest to obtain cellulase from abalone viscera and investigate its application for preparation of functional oligosaccharides. A cellulase was purified from the hepatopancreas of abalone by ammonium sulfate precipitation and two-steps column chromatography. The molecular weight of the cellulase was 45 kDa on SDS-PAGE. Peptide mass fingerprinting analysis yielded 103 amino acid residues, which were identical to cellulases from other species of abalone. Substrate specificity analysis indicated that the cellulase is an endo-1,4-β-glucanase. Hydrolysis of seaweed Porphyra haitanensis polysaccharides by the enzyme produced oligosaccharides with degree of polymerisation of two to four, whose monosaccharide composition was 58% galactose, 4% glucose and 38% xylose. The oligosaccharides revealed 2,2'-diphenyl-1-picrylhydrazyl free radical as well as hydrogen peroxide scavenging activity. It is feasible and meaningful to utilise cellulase from the viscera of abalone for preparation of functional oligosaccharides. © 2015 Society of Chemical Industry. © 2015 Society of Chemical Industry.

INDUCTION SPAWNING FOR THE TROPICAL ABALONE (Haliotis asinina IN THE LABORATORY

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D.E. Djoko Setyono

2006-06-01

Full Text Available The main purpose of this study was to test and understand the effectivity of previous successful treatment to induce spawning in temperate abalone, including the use of hydrogen peroxide, vigorous aeration, desiccation, thermal shock, and UV-irradiated seawater, to induce spawning in the tropical abalone (Haliotis asinina from southern Lombok waters, NTB. Approximately 90% of mature animals conditioned in the laboratory could be spawned successfully. Wild freshly mature broodstock collected in the morning during spring low tide failed to spawn under any treatment tried, while in wild freshly mature broodstock collected in the afternoon during spring low tide, approximately 45% of the males and 37% of the females, spawned successfully under all treatments. Mature animals ready to spawn were usually found creeping up the tanks close to the water surface, and were very active but relaxed, and the foot was soft and flabby. In the laboratory, H. asinina from southern Lombok waters released gametes at night between 11:00 pm and 01:00 am. The conditioned broodstock had average batch fecundity ranged from 50,000 to 435,000 eggs and the freshly caught wild broodstock ranged from 50,000 to 105,000 eggs. Approximately 75% of spawned eggs were found to be ripe and the remaining 25% were unripe. In general, no artificial spawning induction is required to spawn tropical abalone (H. asinina in laboratory (hatchery.

Paralytic shellfish toxins, including deoxydecarbamoyl-STX, in wild-caught Tasmanian abalone (Haliotis rubra).

Science.gov (United States)

Harwood, D Tim; Selwood, Andrew I; van Ginkel, Roel; Waugh, Craig; McNabb, Paul S; Munday, Rex; Hay, Brenda; Thomas, Krista; Quilliam, Michael A; Malhi, Navreet; Dowsett, Natalie; McLeod, Catherine

2014-11-01

For the first time wild-caught Tasmanian abalone, Haliotis rubra, have been reported to contain paralytic shellfish toxins (PSTs). This observation followed blooms of the toxic dinoflagellate Gymnodinium catenatum. No illnesses were reported, but harvesting restrictions were enforced in commercial areas. Abalone were assayed using HPLC-FLD methodology based on AOAC official method 2005.06. An uncommon congener, deoxydecarbamoyl-STX (doSTX), was observed in addition to regulated PSTs as unassigned chromatographic peaks. A quantitative reference material was prepared from contaminated Tasmanian abalone viscera and ampouled at 54.2 μmol/L. The LD50 of doSTX via intraperitoneal injection was 1069 nmol/kg (95% confidence limits 983-1100 nmol/kg), indicating it is nearly 40 times less toxic than STX. A toxicity equivalence factor of 0.042 was generated using the mouse bioassay. Levels of PSTs varied among individuals from the same site, although the toxin profile remained relatively consistent. In the foot tissue, STX, decarbamoyl-STX and doSTX were identified. On a molar basis doSTX was the dominant congener in both foot and viscera samples. The viscera toxin profile was more complex, with other less toxic PST congeners observed and was similar to mussels from the same site. This finding implicates localised dinoflagellate blooms as the PST source in Tasmanian abalone. Copyright © 2014 Elsevier Ltd. All rights reserved.

Gene expression profiling in respond to TBT exposure in small abalone Haliotis diversicolor.

Science.gov (United States)

Jia, Xiwei; Zou, Zhihua; Wang, Guodong; Wang, Shuhong; Wang, Yilei; Zhang, Ziping

2011-10-01

In this study, we investigated the gene expression profiling of small abalone, Haliotis diversicolor by tributyltin (TBT) exposure using a cDNA microarray containing 2473 unique transcripts. Totally, 107 up-regulated genes and 41 down-regulated genes were found. For further investigation of candidate genes from microarray data and EST analysis, quantitative real-time PCR was performed at 6 h, 24 h, 48 h, 96 h and 192 h TBT exposure. 26 genes were found to be significantly differentially expressed in different time course, 3 of them were unknown. Some gene homologues like cellulose, endo-beta-1,4-glucanase, ferritin subunit 1 and thiolester containing protein II CG7052-PB might be the good biomarker candidate for TBT monitor. The identification of stress response genes and their expression profiles will permit detailed investigation of the defense responses of small abalone genes. Published by Elsevier Ltd.

Growth rates of Haliotis rufescens and Haliotis discus hannai in tank culture systems in southern Chile (41.5°S

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Alfonso Mardones

2013-11-01

Full Text Available The increased activity of aquaculture in Chile involves cultivation of salmonids, oysters mussels and other species such, and to a lesser extent species such as red abalone (Haliotis rufescens and Japanese abalone (Haliotis discus hannai. The aim of this study was to evaluate the growth rate of Haliotis rufescens and Haliotis discus hannai fed with different pellet based diets with Macrocystis sp. and Ulva sp., grown in ponds for 13 months. The results for both species denoted that there was an increase in length and biomass during experimental period, existing low growth rates during the austral winter (July-September and increase during the austral summer (December-January. Results are consistent with descriptions of literature that there is high rate of growth during the summer and using diet of brown algae. From the economic standpoint abalone farming would be an economically viable activity for local aquaculture, considering the water quality and food requirements.

A cysteine protease (cathepsin Z) from disk abalone, Haliotis discus discus: Genomic characterization and transcriptional profiling during bacterial infections.

Science.gov (United States)

Godahewa, G I; Perera, N C N; Lee, Sukkyoung; Kim, Myoung-Jin; Lee, Jehee

2017-09-05

Cathepsin Z (CTSZ) is lysosomal cysteine protease of the papain superfamily. It participates in the host immune defense via phagocytosis, signal transduction, cell-cell communication, proliferation, and migration of immune cells such as monocytes, macrophages, and dendritic cells. Hence, CTSZ is also acknowledged as an acute-phase protein in host immunity. In this study, we sought to identify the CTSZ homolog from disk abalone (AbCTSZ) and characterize it at the molecular, genomic, and transcriptional levels. AbCTSZ encodes a protein with 318 amino acids and a molecular mass of 36kDa. The structure of AbCTSZ reveals amino acid sequences that are characteristic of the signal sequence, pro-peptide, peptidase-C1 papain family cysteine protease domain, mini-loop, HIP motif, N-linked glycosylation sites, active sites, and conserved Cys residues. A pairwise comparison revealed that AbCTSZ shared the highest amino acid homology with its molluscan counterpart from Crassostrea gigas. A multiple alignment analysis revealed the conservation of functionally crucial elements of AbCTSZ, and a phylogenetic study further confirmed a proximal evolutionary relationship with its invertebrate counterparts. Further, an analysis of AbCTSZ genomic structure revealed seven exons separated by six introns, which differs from that of its vertebrate counterparts. Quantitative real time PCR (qPCR) detected the transcripts of AbCTSZ in early developmental stages and in eight different tissues. Higher levels of AbCTSZ transcripts were found in trochophore, gill, and hemocytes, highlighting its importance in the early development and immunity of disk abalone. In addition, we found that viable bacteria (Vibrio parahaemolyticus and Listeria monocytogenes) and bacterial lipopolysaccharides significantly modulated AbCTSZ transcription. Collectively, these lines of evidences suggest that AbCTSZ plays an indispensable role in the innate immunity of disk abalone. Copyright © 2017. Published by Elsevier

Effects of rigor status during high-pressure processing on the physical qualities of farm-raised abalone (Haliotis rufescens).

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Hughes, Brianna H; Greenberg, Neil J; Yang, Tom C; Skonberg, Denise I

2015-01-01

High-pressure processing (HPP) is used to increase meat safety and shelf-life, with conflicting quality effects depending on rigor status during HPP. In the seafood industry, HPP is used to shuck and pasteurize oysters, but its use on abalones has only been minimally evaluated and the effect of rigor status during HPP on abalone quality has not been reported. Farm-raised abalones (Haliotis rufescens) were divided into 12 HPP treatments and 1 unprocessed control treatment. Treatments were processed pre-rigor or post-rigor at 2 pressures (100 and 300 MPa) and 3 processing times (1, 3, and 5 min). The control was analyzed post-rigor. Uniform plugs were cut from adductor and foot meat for texture profile analysis, shear force, and color analysis. Subsamples were used for scanning electron microscopy of muscle ultrastructure. Texture profile analysis revealed that post-rigor processed abalone was significantly (P abalone meat was more tender than pre-rigor processed meat, and post-rigor processed foot meat was lighter in color than pre-rigor processed foot meat, suggesting that waiting for rigor to resolve prior to processing abalones may improve consumer perceptions of quality and market value. © 2014 Institute of Food Technologists®

Biomineral repair of abalone shell apertures.

Science.gov (United States)

Cusack, Maggie; Guo, Dujiao; Chung, Peter; Kamenos, Nicholas A

2013-08-01

The shell of the gastropod mollusc, abalone, is comprised of nacre with an outer prismatic layer that is composed of either calcite or aragonite or both, depending on the species. A striking characteristic of the abalone shell is the row of apertures along the dorsal margin. As the organism and shell grow, new apertures are formed and the preceding ones are filled in. Detailed investigations, using electron backscatter diffraction, of the infill in three species of abalone: Haliotis asinina, Haliotis gigantea and Haliotis rufescens reveals that, like the shell, the infill is composed mainly of nacre with an outer prismatic layer. The infill prismatic layer has identical mineralogy as the original shell prismatic layer. In H. asinina and H. gigantea, the prismatic layer of the shell and infill are made of aragonite while in H. rufescens both are composed of calcite. Abalone builds the infill material with the same high level of biological control, replicating the structure, mineralogy and crystallographic orientation as for the shell. The infill of abalone apertures presents us with insight into what is, effectively, shell repair. Copyright © 2013 Elsevier Inc. All rights reserved.

Acute toxicity of live and decomposing green alga Ulva ( Enteromorpha) prolifera to abalone Haliotis discus hannai

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Wang, Chao; Yu, Rencheng; Zhou, Mingjiang

2011-05-01

From 2007 to 2009, large-scale blooms of green algae (the so-called "green tides") occurred every summer in the Yellow Sea, China. In June 2008, huge amounts of floating green algae accumulated along the coast of Qingdao and led to mass mortality of cultured abalone and sea cucumber. However, the mechanism for the mass mortality of cultured animals remains undetermined. This study examined the toxic effects of Ulva ( Enteromorpha) prolifera, the causative species of green tides in the Yellow Sea during the last three years. The acute toxicity of fresh culture medium and decomposing algal effluent of U. prolifera to the cultured abalone Haliotis discus hannai were tested. It was found that both fresh culture medium and decomposing algal effluent had toxic effects to abalone, and decomposing algal effluent was more toxic than fresh culture medium. The acute toxicity of decomposing algal effluent could be attributed to the ammonia and sulfide presented in the effluent, as well as the hypoxia caused by the decomposition process.

Abalone, Haliotis mariae (Wood, 1828, Hatchery and Seed Production Trials in Oman

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Khalfan M. Al-Rashdi

2008-01-01

Full Text Available Hatchery and seed production trials for the Omani endemic abalone Haliotis mariae were carried out at the land-based Mirbat Abalone Seed Production Station in Oman between 1999 and 2000. The methods developed for broodstock conditioning, induction of spawning and fertilization, larval settlement, and the handling of small juveniles are shown. Abalone collected in the post-monsoon period and held for 2 months matured faster than those collected before the monsoon and held for 6 months. Spawning induction of males and females had 63% and 11% success rates respectively, and the morphology of early larval stages is shown. Survival rates of veliger larvae introduced to settlement plates ranged from 35.9% to 73.7%, but the survival of post-larvae was low at 0.1% to 3.6%. The high mortality rate was attributed to invasions of filamentous green- and coralline algae on settlement plates and occurrence of low quantity of diatoms as food. Juveniles reacted best to 2% ethanol as anaesthetic, dropping off culture plates within 4 min and recovering within 17 min. Cultured abalone reached an average shell length of 52.9 mm over 13 months, which translates to an increment of 4.1 mm.mon-1. The overall conclusion of these preliminary research trials confirms  that H. mariae can be cultured successfully in Oman. Further studies on the standardization of the techniques would help in stock enhancement programmes and commercial farming.

Evidence of green fluorescent protein and growth hormone expression in red abalone (Haliotis rufescens larvae

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Mancilla-Sánchez Edgar

2017-02-01

Full Text Available The red abalone Haliotis rufescens is a highly appreciated mollusk in the national and international markets. Due to its natural over-exploitation and low growth rate, several genetic improvements were made, however special efforts are needed to increase its production. This study presents transgenic abalone’s larvae expressing green fluorescent protein (GFP fused to Cobia (Rachycentron canadum Growth Hormone (GH using sperm media transgenesis technique (SMT, pAcGFP1-N vector under the control of cytomegalovirus (CMV promoter. Sperms were exposed to three voltages (0.5, 0.75 and 1.0 Kv using a micropulser electroporator (Bio-Rad®. The highest GFP-GH expression average (40% was obtained in abalone larvae at 0.75 v. GFP and GH transgenes were positively detected by PCR, western blot and confocal microscope, respectively.

Molecular cloning and characterization of prohormone convertase 1 gene in abalone (Haliotis diversicolor supertexta).

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Zhou, Jin; Cai, Zhong-hua

2010-03-01

Prohormone convertases (PCs) are calcium-dependent serine endoproteases of the subtilisin family that play a key role in the posttranslational processing of precursors for bioactive peptides. In this study, the cDNA of PC1 from abalone (Haliotis diversicolor supertexta) was cloned and sequenced. The PC1 cDNA consisted of 2216 bp with an open reading frame of 2010 bp encoding a 670 amino acid peptide. Comparative structural analysis revealed that abalone PC1 shared high similarity and identity with most PC counterparts. The profile of deduced peptide of PC1 was composed of an N-terminal signal peptide, a prosegment domain, a catalytic domain and a P domain, which were common in many species. Sequence analysis indicated that the abalone PC1 was highly conserved in catalytic domain, including three conserved serine catalytic signatures that comprised a catalytic triad active center. Also conserved were the potential cleavage site for release of the mature peptide, a cognate integrin binding site RGD in P domain, and four cysteine residues involved in forming an intrachain disulfide bridge. To further investigate the functions of PC1 in abalone, real-time quantitative PCR was performed to determine the expression level of this gene at three different reproduction stages (i.e. pre-, during- and post-breeding). Results indicated that PC1 was expressed throughout the three stages but the expression levels varied with the timepoints and different tissues in abalone. The expression levels of PC1 in digestive gland were much higher than those of the gonad. In female abalone, the expression of PC1 was higher at pre-breeding and during-breeding stages (Pabalone reproduction process (e.g. spawning or sperming). PC1 is a potential prohormone processing enzyme and it may play a critical role in abalone physiological processes related to reproduction. 2009 Elsevier Inc. All rights reserved.

Abalone R&D at AQD

OpenAIRE

Castanos, Milagros T.

1997-01-01

Details are given of the results of research conducted at the SEAFDEC Aquaculture Department on abalone (Haliotis asinina). The following areas are covered: reproductive biology; induced spawning; raising abalone in the hatchery; and, cage culture trials.

Toxicokinetics and biotransformation of p-nitrophenol in red abalone (Haliotis rufescens)

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TenBrook, Patti L.; Kendall, Shellie M.; Viant, Mark R.; Tjeerdema, Ronald S

2003-02-26

Red abalone (Haliotis rufescens) were exposed to 3.6 {mu}M (0.5 ppm) {sup 14}C-labelled p-nitrophenol (PNP) for 24 h, then were allowed to depurate in clean seawater for another 24 h. Absorption, conditional uptake clearance and elimination rate constants were 0.12{+-}0.04 h{sup -1}, 3.2{+-}1.1 ml g{sup -1} h{sup -1} and 0.05{+-}0.02 h{sup -1}, respectively. The sigmoidal shape of the PNP uptake curve suggests a biphasic process. A whole-organism total concentration factor (TCF) of 2.37{+-}0.07 was determined from equilibrium tissue and water concentrations, with the highest concentration of PNP plus metabolites found in gill tissue (11.8{+-}0.2 nmol g{sup -1}, wet weight). Digestive gland, foot muscle and remaining body tissues accumulated 8.8{+-}0.9, 7.7{+-}0.6 and 7.5{+-}0.6 nmol g{sup -1} radiolabelled residues, respectively. Abalone depurated 91.6% of absorbed PNP within 24 h, of which 87.5{+-}3.1% was unmetabolized parent compound, 13.1{+-}3.1% was p-nitrophenylsulfate, 0.32{+-}0.09% was p-nitroanisole, and 0.14{+-}0.07% was p-acetamidophenol.

Effects of Multiple Stressors on Red Abalone (Haliotis rufescens) Fertilization Success

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Boch, C. A.; Aalto, E.; De Leo, G.; Litvin, S.; Lovera, C.; Micheli, F.; Woodson, C. B.; Monismith, S. G.; Barry, J. P.

2016-02-01

Acidification, hypoxia, and ocean warming are escalating threats in the world's coastal waters, with potentially severe consequences for marine life and ocean-based economies. In particular, eastern boundary current ecosystems, including the California Current Large Marine Ecosystem (CCLME), are experiencing large-scale declines in pH and dissolved oxygen (DO)—with the latter linked to changes in thermal stratification and shoaling of the oxygen minimum zone. To examine the consequences of ocean acidification and other climate-related changes in oceanographic conditions on nearshore marine populations within the CCLME, we are assessing the potential effects of current and future upwelling-type conditions on the population dynamics of the red abalone (Haliotis rufescens), with a focus on sensitive early life history phases (e.g., fertilization, larval development, and juvenile growth and survival) expected to be important determinants of population dynamics. Here, we present the first experimental results on the impacts of combined exposures of low pH and low DO on abalone fertilization success. Our results show that abalone fertilization success is significantly reduced when the gametes are exposed to a decrease in seawater pH from 8.0 to 7.2. Furthermore, low pH in combination with hypoxic exposure—e.g., a decrease in dissolved oxygen from 6 mg/L DO to 1 mg/L DO—does not further decrease fertilization rates, suggesting a lack of synergistic or additive effects of these multiple stressors on the reduction of fertilization success. Although the focus of this study is to characterize the effects of multiple stressors on the early life history of abalone, the implications of these results are expected to be relevant for a variety of marine taxa with similar reproductive modes.

Construction of the BAC Library of Small Abalone (Haliotis diversicolor) for Gene Screening and Genome Characterization.

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Jiang, Likun; You, Weiwei; Zhang, Xiaojun; Xu, Jian; Jiang, Yanliang; Wang, Kai; Zhao, Zixia; Chen, Baohua; Zhao, Yunfeng; Mahboob, Shahid; Al-Ghanim, Khalid A; Ke, Caihuan; Xu, Peng

2016-02-01

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.

Transcriptional analysis of disk abalone (Haliotis discus discus) antioxidant enzymes against marine bacteria and virus challenge.

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De Zoysa, Mahanama; Whang, Ilson; Nikapitiya, Chamilani; Oh, Chulhong; Choi, Cheol Young; Lee, Jehee

2011-07-01

Diverse antioxidant enzymes are essential for marine organisms to overcome oxidative stress as well as for the fine-tuning of immune reactions through activating different signal transduction pathways. This study describes the transcriptional analysis of antioxidant enzymes of disk abalone by challenging with bacteria (Vibrio alginolyticus, Vibrio parahemolyticus, and Listeria monocytogenes) and viral hemorrhagic septicemia virus (VHSV). Upon bacteria and VHSV challenge, Manganese superoxide dismutase (MnSOD), Copper, Zinc superoxide dismutase (CuZnSOD), catalase, thioredoxin peroxidase (TPx), Selenium-dependent glutathione peroxidase (SeGPx), and thioredoxin-2 (TRx-2) expression levels were altered in gills, and hemocytes at different magnitudes. In gills, only MnSOD, catalase, and SeGPx genes were completely upregulated by post-challenge of bacterial and VHSV. Among them, SeGPx demonstrated strong upregulation by 16-fold (bacteria) and 2-fold (VHSV) in gills, and 5-fold (bacteria) and 3.0-fold (VHSV) in hemocytes. None of the genes examined were downregulated (in gills and hemocytes) by bacteria challenge even though CuZnSOD and TPx showed downregulation (completely) in hemocytes by VHSV. In general, abalone hemocytes had lower potential to induce antioxidant enzyme transcripts upon bacteria and VHSV challenge than gills. Based upon these results, we suggest that abalones induce oxidative stress in tissues during the bacteria and VHSV challenge, and the identified response of antioxidant enzymes could be supported for maintaining a low-level of reactive oxygen species (ROS) that may serve as a signal for activating immune reactions against pathogenic conditions. Copyright © 2011 Elsevier Ltd. All rights reserved.

Effects of chemical cues on larval survival, settlement and metamorphosis of abalone Haliotis asinina

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Wang, Xiaobing; Bai, Yang; Huang, Bo

2010-11-01

Low larval survival, poor settlement, and abnormal metamorphosis are major problems in seed production of donkey-ear abalone Haliotis asinina. We examined the effects of chemical cues including epinephrine, nor-epinephrine, and serotonin on larval survival, settlement, and metamorphosis in order to determine the possibility of using these chemicals to induce the problems. The results show that epinephrine could enhance metamorphosis rate at 10-6 mol/L only but higher concentrations (10-3-10-4 mol/L); and nor-epinephrine could inhibit the performance significantly, and serotonin could increase significantly the performance at a wide-range concentration (10-3-10-6 mol/L). Treatment with serotonin at 10-5 mol/L for 72 hours resulted in the highest settlement rate (42.2%) and survival rate (49.3%), while at 10-4 mol/L for 72 hours resulted in the highest metamorphosis rate (38.8%). Therefore, serotonin may be used as a fast metamorphosis inducer in abalone culture.

Toxicokinetics and biotransformation of p-nitrophenol in red abalone (Haliotis rufescens)

International Nuclear Information System (INIS)

TenBrook, Patti L.; Kendall, Shellie M.; Viant, Mark R.; Tjeerdema, Ronald S.

2003-01-01

Red abalone (Haliotis rufescens) were exposed to 3.6 μM (0.5 ppm) 14 C-labelled p-nitrophenol (PNP) for 24 h, then were allowed to depurate in clean seawater for another 24 h. Absorption, conditional uptake clearance and elimination rate constants were 0.12±0.04 h -1 , 3.2±1.1 ml g -1 h -1 and 0.05±0.02 h -1 , respectively. The sigmoidal shape of the PNP uptake curve suggests a biphasic process. A whole-organism total concentration factor (TCF) of 2.37±0.07 was determined from equilibrium tissue and water concentrations, with the highest concentration of PNP plus metabolites found in gill tissue (11.8±0.2 nmol g -1 , wet weight). Digestive gland, foot muscle and remaining body tissues accumulated 8.8±0.9, 7.7±0.6 and 7.5±0.6 nmol g -1 radiolabelled residues, respectively. Abalone depurated 91.6% of absorbed PNP within 24 h, of which 87.5±3.1% was unmetabolized parent compound, 13.1±3.1% was p-nitrophenylsulfate, 0.32±0.09% was p-nitroanisole, and 0.14±0.07% was p-acetamidophenol

Epipodial Tentacle Gene Expression and Predetermined Resilience to Summer Mortality in the Commercially Important Greenlip Abalone, Haliotis laevigata.

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Shiel, Brett P; Hall, Nathan E; Cooke, Ira R; Robinson, Nicholas A; Strugnell, Jan M

2017-04-01

"Summer mortality" is a phenomenon that occurs during warm water temperature spikes that results in the mass mortality of many ecologically and economically important mollusks such as abalone. This study aimed to determine whether the baseline gene expression of abalone before a laboratory-induced summer mortality event was associated with resilience to summer mortality. Tentacle transcriptomes of 35 greenlip abalone (Haliotis laevigata) were sequenced prior to the animals being exposed to an increase in water temperature-simulating conditions which have previously resulted in summer mortality. Abalone derived from three source locations with different environmental conditions were categorized as susceptible or resistant to summer mortality depending on whether they died or survived after the water temperature was increased. We detected two genes showing significantly higher expression in resilient abalone relative to susceptible abalone prior to the laboratory-induced summer mortality event. One of these genes was annotated through the NCBI non-redundant protein database using BLASTX to an anemone (Exaiptasia pallida) Transposon Ty3-G Gag Pol polyprotein. Distinct gene expression signatures were also found between resilient and susceptible abalone depending on the population origin, which may suggest divergence in local adaptation mechanisms for resilience. Many of these genes have been suggested to be involved in antioxidant and immune-related functions. The identification of these genes and their functional roles have enhanced our understanding of processes that may contribute to summer mortality in abalone. Our study supports the hypothesis that prestress gene expression signatures are indicative of the likelihood of summer mortality.

The immune response of Taiwan abalone Haliotis diversicolor supertexta and its susceptibility to Vibrio parahaemolyticus at different salinity levels.

Science.gov (United States)

Cheng, Winton; Juang, Feng-Ming; Chen, Jiann-Chu

2004-03-01

Addition of NaCl at 2.5% to 3.5% to tryptic soy broth (TSB) significantly increased the growth of Vibrio parahaemolyticus. Taiwan abalone Haliotis diversicolor supertexta held in 30 per thousand seawater were injected with V. parahaemolyticus grown in TSB containing NaCl at 0.5, 1.5, 2.5, 3.5 and 4.5% at a dose of 1.6 x 10(5)colony-forming units (cfu) abalone(-1). After 48 h, the cumulative mortality was significantly higher for the abalone challenged with V. parahaemolyticus grown in 2.5% than those grown in 0.5 and 1.5% NaCl. In other experiments, abalones held in 30 per thousand seawater were injected with TSB-grown V. parahaemolyticus (1.6 x 10(5)cfu abalone(-1)), and then transferred to 20, 25, 30 and 35 per thousand seawater. All abalones held in 20 per thousand were killed in 48 h. The mortality of V. parahaemolyticus-injected abalone held in 30 per thousand was significantly lower over 24-120 h. Abalone held in 30 per thousand seawater and then transferred to 20, 25, 30 and 35 per thousand were examined for THC (total haemocyte count), phenoloxidase activity, respiratory burst, phagocytic activity and clearance efficiency of V. parahemolyticus after 24 and 72 h. The THC increased directly related with salinity levels. Phenoloxidase activity, respiratory burst, phagocytic activity and clearance efficiency of V. parahaemolyticus decreased significantly for the abalone in 20, 25 and 35 per thousand. It is concluded that the abalone transferred from 30 per thousand to 20, 25 and 35 per thousand had reduced immune ability and decreased resistance against V. parahaemolyticus infection.

Isolation and identification of lactic acid bacteria from abalone (Haliotis asinina as a potential candidate of probiotic

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YAYAN SOFYAN

2010-01-01

Full Text Available Sarkono, Faturrahman, Sofyan Y. 2010. Isolation and identification of lactic acid bacteria from abalone (Haliotis asinina as a potential candidate of probiotic. Nusantara Bioscience 2: 38-42. The purpose of this study was to isolate, select and characterize lactic acid bacteria (LAB from abalone as a potential candidate probiotic in abalone cultivation system. Selective isolation of LAB performed using de Man Rogosa Sharpe medium. LAB isolate that potential as probiotics was screened. Selection was based on its ability to suppress the growth of pathogenic bacteria, bacterial resistance to acidic conditions and bacterial resistance to bile salts (bile. Further characterization and identification conducted to determine the species. The results showed that two of the ten isolates potential to be developed as probiotic bacteria that have the ability to inhibit several pathogenic bacteria such as Eschericia coli, Bacillus cereus dan Staphylococus aureus, able to grow at acidic condition and bile tolerance during the incubation for 24 hour. Based on the API test kit, the both of isolate identified as members of the species Lactobacillus paracasei ssp. paracasei.

Proteomic profiling of eggs from a hybrid abalone and its parental lines: Haliotis discus hannai Ino and Haliotis gigantea.

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Di, Guilan; Luo, Xuan; Huang, Miaoqin; Chen, Jun; Kong, Xianghui; Miao, Xiulian; Ke, Caihuan

2015-12-01

Proteomic analysis was performed on the eggs of hybrid abalone and their corresponding parental lines. A total of 915 ± 19 stained protein spots were detected from Haliotis discus hannai♀ × H. discus hannai♂ (DD), 935 ± 16 from H. gigantea♀ × H. gigantea♂ (GG) and 923 ± 13 from H. gigantea♀ × H. discus hannai♂ (GD). The spots from DD and GD were clustered together. The distance between DD and GG was maximal by hierarchical cluster analysis. A total of 112 protein gel spots were identified; of these, 59 were abalone proteins. The proteins were involved in major biological processes including energy metabolism, proliferation, apoptosis, signal transduction, immunity, lipid metabolism, electron carrier proteins, protein biosynthesis and decomposition, and cytoskeletal structure. Three of 20 differential expression protein spots involved in energy metabolism exhibited as upregulated in GD, 13 spots exhibited additivity, and four spots exhibited as downregulated in the offspring. Eleven protein spots were expressed at the highest level in DD. The proteins involved in stress responses included superoxide dismutase, peroxiredoxin 6, thioredoxin peroxidase and glutathione-S-transferase. Two of seven differential expression protein spots involved in response to stress exhibited as upregulated in GD, three exhibited additivity, and two exhibited as downregulated. These results might suggest that proteomic approaches are suitable for the analysis of hybrids and the functional prediction of abalone hybridization. © 2015 Stichting International Foundation for Animal Genetics.

Uptake, distribution and depuration of paralytic shellfish toxins from Alexandrium minutum in Australian greenlip abalone, Haliotis laevigata.

Science.gov (United States)

Dowsett, Natalie; Hallegraeff, Gustaaf; van Ruth, Paul; van Ginkel, Roel; McNabb, Paul; Hay, Brenda; O'Connor, Wayne; Kiermeier, Andreas; Deveney, Marty; McLeod, Catherine

2011-07-01

Farmed greenlip abalone Haliotis laevigata were fed commercial seaweed-based food pellets or feed pellets supplemented with 8 × 10⁵ Alexandrium minutum dinoflagellate cells g⁻¹ (containing 12 ± 3.0 μg STX-equivalent 100 g⁻¹, which was mainly GTX-1,4) every second day for 50 days. Exposure of abalone to PST supplemented feed for 50 days did not affect behaviour or survival but saw accumulation of up to 1.6 μg STX-equivalent 100 g⁻¹ in the abalone foot tissue (muscle, mouth without oesophagus and epipodial fringe), which is ∼50 times lower than the maximum permissible limit (80 μg 100 g⁻¹ tissue) for PSTs in molluscan shellfish. The PST levels in the foot were reduced to 0.48 μg STX-equivalent 100 g⁻¹ after scrubbing and removal of the pigment surrounding the epithelium of the epipodial fringe (confirmed by both HPLC and LC-MS/MS). Thus, scrubbing the epipodial fringe, a common procedure during commercial abalone canning, reduced PST levels by ∼70%. Only trace levels of PSTs were detected in the viscera (stomach, gut, heart, gonad, gills and mantle) of the abalone. A toxin reduction of approximately 73% was observed in STX-contaminated abalone held in clean water and fed uncontaminated food over 50 days. The low level of PST uptake when abalone were exposed to high numbers of A. minutum cells over a prolonged period may indicate a low risk of PSP poisoning to humans from the consumption of H. laevigata that has been exposed to a bloom of potentially toxic A. minutum in Australia. Further research is required to establish if non-dietary accumulation can result in significant levels of PSTs in abalone. Crown Copyright © 2011. Published by Elsevier Ltd. All rights reserved.

Genomic Characterization of a Novel Phage Found in Black Abalone (Haliotis cracherodii) Infected with Withering Syndrome

Science.gov (United States)

Closek, C. J.; Langevin, S.; Burge, C. A.; Crosson, L.; White, S.; Friedman, C. S.

2016-02-01

Withering syndrome (WS), caused by the bacterium Candidatus Xenohaliotis californiensis, a Rickettsia-like organism (RLO), infects many species of abalone. Black abalone (Haliotis cracherodii), one of two endangered species of abalone, has experienced high population losses along the California coast due to WS. Recently, we observed reduced pathogenicity and mortality events in RLO-infected abalone when a novel bacteriophage (phage) was also present. To better understand phage-bacterium dynamics and develop more informative diagnostic tools, we sequenced the genome of the novel phage associated with the RLO responsible for WS. Metagenomic sequencing libraries were prepared with extracted genomic DNA from two experimentally infected H. cracherodii and phage sequences were enriched using hydroxyapatite chromatography normalization. Normalized libraries were individually barcoded and sequenced with Illumina MiSeq. Raw sequence reads were processed using VIrominer and de novo assembly produced one single phage-like contig (35.7Kb) from the experimentally infected abalone. This highly divergent genome had closest homology with a virus associated with abalone shriveling syndrome (SS). Of the 34 predicted ORFs, overlapping homology with the SS virus ranged from 20-72%, demonstrating the phage sequenced is genetically distinct from any known phage. The phage-like sequences represented a significant portion of the total reads sequenced ( 2 million of the 12 million paired-end reads; 17%) and we obtained 94,000X coverage across the novel phage genome. Beyond characterization of this novel phage, which appears to reduce pathogenicity of the RLO, the genome enabled us to develop quantitative PCR and in situ hybridization assays as diagnostic tools. These tools allow us to detect and quantify this phage in the endangered H. cracherodii.

Alternative Splicing Profile and Sex-Preferential Gene Expression in the Female and Male Pacific Abalone Haliotis discus hannai.

Science.gov (United States)

Kim, Mi Ae; Rhee, Jae-Sung; Kim, Tae Ha; Lee, Jung Sick; Choi, Ah-Young; Choi, Beom-Soon; Choi, Ik-Young; Sohn, Young Chang

2017-03-09

In order to characterize the female or male transcriptome of the Pacific abalone and further increase genomic resources, we sequenced the mRNA of full-length complementary DNA (cDNA) libraries derived from pooled tissues of female and male Haliotis discus hannai by employing the Iso-Seq protocol of the PacBio RSII platform. We successfully assembled whole full-length cDNA sequences and constructed a transcriptome database that included isoform information. After clustering, a total of 15,110 and 12,145 genes that coded for proteins were identified in female and male abalones, respectively. A total of 13,057 putative orthologs were retained from each transcriptome in abalones. Overall Gene Ontology terms and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways analyzed in each database showed a similar composition between sexes. In addition, a total of 519 and 391 isoforms were genome-widely identified with at least two isoforms from female and male transcriptome databases. We found that the number of isoforms and their alternatively spliced patterns are variable and sex-dependent. This information represents the first significant contribution to sex-preferential genomic resources of the Pacific abalone. The availability of whole female and male transcriptome database and their isoform information will be useful to improve our understanding of molecular responses and also for the analysis of population dynamics in the Pacific abalone.

Alternative Splicing Profile and Sex-Preferential Gene Expression in the Female and Male Pacific Abalone Haliotis discus hannai

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Mi Ae Kim

2017-03-01

Full Text Available In order to characterize the female or male transcriptome of the Pacific abalone and further increase genomic resources, we sequenced the mRNA of full-length complementary DNA (cDNA libraries derived from pooled tissues of female and male Haliotis discus hannai by employing the Iso-Seq protocol of the PacBio RSII platform. We successfully assembled whole full-length cDNA sequences and constructed a transcriptome database that included isoform information. After clustering, a total of 15,110 and 12,145 genes that coded for proteins were identified in female and male abalones, respectively. A total of 13,057 putative orthologs were retained from each transcriptome in abalones. Overall Gene Ontology terms and Kyoto Encyclopedia of Genes and Genomes (KEGG pathways analyzed in each database showed a similar composition between sexes. In addition, a total of 519 and 391 isoforms were genome-widely identified with at least two isoforms from female and male transcriptome databases. We found that the number of isoforms and their alternatively spliced patterns are variable and sex-dependent. This information represents the first significant contribution to sex-preferential genomic resources of the Pacific abalone. The availability of whole female and male transcriptome database and their isoform information will be useful to improve our understanding of molecular responses and also for the analysis of population dynamics in the Pacific abalone.

Effect of dietary lipid on the growth, fatty acid composition and Δ5 Fads expression of abalone ( Haliotis discus hannai Ino) hepatopancreas

Science.gov (United States)

Li, Mingzhu; Mai, Kangsen; Ai, Qinghui; He, Gen; Xu, Wei; Zhang, Wenbing; Zhang, Yanjiao; Zhou, Huihui; Liufu, Zhiguo

2015-04-01

This study investigated the effect of dietary lipid on the growth, fatty acid composition and Δ5 fatty acyl desaturase genes ( Fads) expression of juvenile abalone ( Haliotis discus hannai Ino) hepatopancreas. Six purified diets were formulated to contain tripalmitin (TP), olive oil (OO, 72.87% 18:1n-9), grape seed oil (GO, 68.67% 18:2n-6), linseed oil (LO, 70.48% 18:3n-3), ARA oil (AO, 41.81% ARA) or EPA oil (EO, 44.09% EPA and 23.67% DAH). No significant difference in survival rate was observed among abalone fed with different diets. Weight gain rate ( WGR) and daily growth rate of shell length ( DGR SL) were significantly increased in abalone fed with diets containing OO, AO and EO, but decreased in abalone fed with LO diet ( P abalone fed with GO than those fed with TP, OO, LO and EO ( P abalone fed with LO was significantly higher than those in abalone fed with TP, OO, GO and AO ( P abalone fed with OO. The expression of Δ5 Fads in hepatopancreas of abalone was enhanced by high concentration of 18:3n-3 and suppressed by dietary LC-PUFAs; however it was not affected by dietary high concentration of 18:1n-9 or 18:2n-6. These results provided valuable information for understanding the synthesis of LC-PUFAs and nutritional regulation of Δ5 Fads expression in abalone.

Amplified fragment length polymorphism analysis to assess crossover interference and homozygosity in gynogenetic diploid Pacific abalone (Haliotis discus hannai).

Science.gov (United States)

Nie, H-T; Li, Q; Kong, L-F

2014-06-01

Recombination analysis in gynogenetic diploids is a powerful tool for assessing the degree of inbreeding, investigating crossover events and understanding chiasma interference during meiosis. To estimate the marker-centromere recombination rate, the inheritance pattern of 654 amplified fragment length polymorphism (AFLP) markers was examined in the 72-h veliger larvae of two meiogynogenetic diploid families in the Pacific abalone (Haliotis discus hannai). The second-division segregation frequency (y) of the AFLP loci ranged from 0.00 to 0.96, with 23.9% of loci showing y-values higher than 0.67, evidencing the existence of interference. The average recombination frequency across the 654 AFLP loci was 0.45, allowing estimation of the fixation index of 0.55, indicating that meiotic gynogenesis could provide an effective means of rapid inbreeding in the Pacific abalone. The AFLP loci have a small proportion (4.4%) of y-values greater than 0.90, suggesting that a relatively low or intermediate degree of chiasma interference occurred in the abalone chromosomes. The information obtained in this study will enhance our understanding of the abalone genome and will be useful for genetic studies in the species. © 2014 Stichting International Foundation for Animal Genetics.

Vibrio harveyi adheres to and penetrates tissues of the European abalone Haliotis tuberculata within the first hours of contact.

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Cardinaud, Marion; Barbou, Annaïck; Capitaine, Carole; Bidault, Adeline; Dujon, Antoine Marie; Moraga, Dario; Paillard, Christine

2014-10-01

Vibrio harveyi is a marine bacterial pathogen responsible for episodic epidemics generally associated with massive mortalities in many marine organisms, including the European abalone Haliotis tuberculata. The aim of this study was to identify the portal of entry and the dynamics of infection of V. harveyi in the European abalone. The results indicate that the duration of contact between V. harveyi and the European abalone influences the mortality rate and precocity. Immediately after contact, the epithelial and mucosal area situated between the gills and the hypobranchial gland was colonized by V. harveyi. Real-time PCR analyses and culture quantification of a green fluorescent protein-tagged strain of V. harveyi in abalone tissues revealed a high density of bacteria adhering to and then penetrating the whole gill-hypobranchial gland tissue after 1 h of contact. V. harveyi was also detected in the hemolymph of a significant number of European abalones after 3 h of contact. In conclusion, this article shows that a TaqMan real-time PCR assay is a powerful and useful technique for the detection of a marine pathogen such as V. harveyi in mollusk tissue and for the study of its infection dynamics. Thus, we have revealed that the adhesion and then the penetration of V. harveyi in European abalone organs begin in the first hours of contact. We also hypothesize that the portal of entry of V. harveyi in the European abalone is the area situated between the gills and the hypobranchial gland. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

Identification of differentially expressed reproductive and metabolic proteins in the female abalone (Haliotis laevigata) gonad following artificial induction of spawning.

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Mendoza-Porras, Omar; Botwright, Natasha A; Reverter, Antonio; Cook, Mathew T; Harris, James O; Wijffels, Gene; Colgrave, Michelle L

2017-12-01

Inefficient control of temperate abalone spawning prevents pair-wise breeding and production of abalone with highly marketable traits. Traditionally, abalone farmers have used a combination of UV irradiation and application of temperature gradients to the tank water to artificially induce spawning. Proteins are known to regulate crucial processes such as respiration, muscle contraction, feeding, growth and reproduction. Spawning as a pre-requisite of abalone reproduction is likely to be regulated, in part, by endogenous proteins. A first step in elucidating the mechanisms that regulate spawning is to identify which proteins are directly involved during spawning. The present study examined protein expression following traditional spawning induction in the Haliotis laevigata female. Gonads were collected from abalone in the following physiological states: (1) spawning; (2) post-spawning; and (3) failed-to-spawn. Differential protein abundance was initially assessed using two-dimensional difference in-gel electrophoresis coupled with mass spectrometry for protein identification. A number of reproductive proteins such as vitellogenin, vitelline envelope zona pellucida domain 29 and prohibitin, and metabolic proteins such as thioredoxin peroxidase, superoxide dismutase and heat shock proteins were identified. Differences in protein abundance levels between physiological states were further assessed using scheduled multiple reaction monitoring mass spectrometry. Positive associations were observed between the abundance of specific proteins, such as heat shock cognate 70 and peroxiredoxin 6, and the propensity or failure to spawn in abalone. These findings have contributed to better understand both the effects of oxidative and heat stress over abalone physiology and their influence on abalone spawning. Crown Copyright © 2016. Published by Elsevier Inc. All rights reserved.

Enzymatic properties and primary structures of two α-amylase isozymes from the Pacific abalone Haliotis discus hannai

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Kumagai, Yuya; Satoh, Takuya; Inoue, Akira; Ojima, Takao

2013-01-01

Two α-amylase (EC 3.2.1.1) isozymes, HdAmy58 and HdAmy82, with approximate molecular masses of 58 kDa and 82 kDa, respectively, were isolated from the digestive fluid of the Pacific abalone Haliotis discus hannai. Optimal temperatures and pHs for HdAmy58 and HdAmy82 were at 30℃ and 6.7, and 30℃ and 6.1, respectively. Both enzymes similarly degraded starch, glycogen, and maltooligosaccharides larger than maltotriose producing maltose and maltotriose as the major degradation products. However, ...

Proteomic analysis of muscle between hybrid abalone and parental lines Haliotis gigantea Reeve and Haliotis discus hannai Ino

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Di, G; Luo, X; You, W; Zhao, J; Kong, X; Ke, C

2015-01-01

To understand the potential molecular mechanism of heterosis, protein expression patterns were compared from hybrids of Haliotis gigantea (G) and Haliotis discus hannai (D) using two-dimensional gel electrophoresis (2-DE) and matrix-assisted laser desorption/ionization time-of-flight/time-of-flight analyses. Expression differences were observed in muscle samples from the four groups with 673±21.0 stained spots for H. discus hannai ♀ × H. discus hannai ♂ (DD), 692±25.6 for H. gigantea ♀ × H. gigantea ♂ (GG), 679±16.2 for H. discus hannai ♀ × H. gigantea ♂ (DG) (F1 hybrid) and 700±19 for H. gigantea ♀ × H. discus hannai ♂ (GD) (F1 hybrid). Different 2-DE image muscle protein spots had a mirrored relationship between purebreds and the F1 hybrid, suggesting that all stained spots in F1 hybrid muscle were on 2-DEs from parents. DD and DG clustered together first, and then clustered with GD, whereas the distance of DD and GG was maximal according to hierarchical cluster analysis. We identified 136 differentially expressed protein spots involved in major biological processes, including energy metabolism and stress response. Most energy metabolism proteins were additive, and stress-induced proteins displayed additivity or over-dominance. In these 136 identified protein spots, hybrid offspring with additivity or over-dominance accounted for 68.38%. Data show that a proteomic approach can provide functional prediction of abalone interspecific hybridization. PMID:25669609

Proteomic analysis of the organic matrix of the abalone Haliotis asinina calcified shell

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Degnan Bernard M

2010-11-01

Full Text Available Abstract Background The formation of the molluscan shell is regulated to a large extent by a matrix of extracellular macromolecules that are secreted by the shell forming tissue, the mantle. This so called "calcifying matrix" is a complex mixture of proteins and glycoproteins that is assembled and occluded within the mineral phase during the calcification process. While the importance of the calcifying matrix to shell formation has long been appreciated, most of its protein components remain uncharacterised. Results Recent expressed sequence tag (EST investigations of the mantle tissue from the tropical abalone (Haliotis asinina provide an opportunity to further characterise the proteins in the shell by a proteomic approach. In this study, we have identified a total of 14 proteins from distinct calcified layers of the shell. Only two of these proteins have been previously characterised from abalone shells. Among the novel proteins are several glutamine- and methionine-rich motifs and hydrophobic glycine-, alanine- and acidic aspartate-rich domains. In addition, two of the new proteins contained Kunitz-like and WAP (whey acidic protein protease inhibitor domains. Conclusion This is one of the first comprehensive proteomic study of a molluscan shell, and should provide a platform for further characterization of matrix protein functions and interactions.

Effect of drying process assisted by high-pressure impregnation on protein quality and digestibility in red abalone (Haliotis rufescens).

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Cepero-Betancourt, Yamira; Oliva-Moresco, Patricio; Pasten-Contreras, Alexis; Tabilo-Munizaga, Gipsy; Pérez-Won, Mario; Moreno-Osorio, Luis; Lemus-Mondaca, Roberto

2017-10-01

Abalone (Haliotis spp.) is an exotic seafood product recognized as a protein source of high biological value. Traditional methods used to preserve foods such as drying technology can affect their nutritional quality (protein quality and digestibility). A 28-day rat feeding study was conducted to evaluate the effects of the drying process assisted by high-pressure impregnation (HPI) (350, 450, and 500 MPa × 5 min) on chemical proximate and amino acid compositions and nutritional parameters, such as protein efficiency ratio (PER), true digestibility (TD), net protein ratio, and protein digestibility corrected amino acid score (PDCAAS) of dried abalone. The HPI-assisted drying process ensured excellent protein quality based on PER values, regardless of the pressure level. At 350 and 500 MPa, the HPI-assisted drying process had no negative effect on TD and PDCAAS then, based on nutritional parameters analysed, we recommend HPI-assisted drying process at 350 MPa × 5 min as the best process condition to dry abalone. Variations in nutritional parameters compared to casein protein were observed; nevertheless, the high protein quality and digestibility of HPI-assisted dried abalones were maintained to satisfy the metabolic demands of human beings.

Growth of the European abalone ( Haliotis tuberculata L.) in situ: Seasonality and ageing using stable oxygen isotopes

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Roussel, Sabine; Huchette, Sylvain; Clavier, Jacques; Chauvaud, Laurent

2011-02-01

The ormer, Haliotis tuberculata is the only European abalone species commercially exploited. The determination of growth and age in the wild is an important tool for fisheries and aquaculture management. However, the ageing technique used in the past in the field is unreliable. The stable oxygen isotope composition ( 18O/ 16O) of the shell depends on the temperature and oxygen isotope composition of the ambient sea water. The stable oxygen isotope technique, developed to study paleoclimatological changes in shellfish, was applied to three H. tuberculata specimens collected in north-west Brittany. For the specimens collected, the oxygen isotope ratios of the shell reflected the seasonal cycle in the temperature. From winter-to-winter cycles, estimates of the age and the annual growth increment, ranging from 13 to 55 mm per year were obtained. This study shows that stable oxygen isotopes can be a reliable tool for ageing and growth studies of this abalone species in the wild, and for validating other estimates.

Immunological changes in response to herpesvirus infection in abalone Haliotis laevigata and Haliotis rubra hybrids.

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Dang, Vinh T; Benkendorff, Kirsten; Corbeil, Serge; Williams, Lynette M; Hoad, John; Crane, Mark St J; Speck, Peter

2013-02-01

Australian abalone production has been affected by outbreaks of abalone viral ganglioneuritis (AVG) caused by a herpesvirus (AbHV). In this study, we undertook experimental transmission trials by immersion to study the abalone immune response to infection with AbHV. Representative cellular and humoural immune parameters of abalone, including total haemocyte count (THC), superoxide anion (SO) and antiviral activity against herpes simplex virus type 1 (HSV-1), were examined in apparently healthy (sub-clinical) and moribund abalone after challenge. In the early infection, sub-clinical stage (days 1-3), THC was found to increase significantly in infected abalone. TaqMan qPCR confirmed 20.5% higher viral load in moribund abalone compared to apparently healthy abalone, indicating that the abundance of AbHV within abalone is linked to their clinical signs. At the clinical stage of infection, THC was significantly lower in moribund abalone, but increased in AbHV-exposed but apparently healthy abalone, in comparison to non-infected controls. SO was reduced in all abalone that were PCR-positive for AbHV. THC and SO level were found to be negatively correlated with the presence of AbHV in abalone, but no effect of AbVH exposure was observed on the haemolymph antiviral activity. These results suggest that abalone mount an initial cellular immune response to AbHV infection, but this response cannot be sustained under high viral loads, leading to mortality. Copyright © 2012 Elsevier Ltd. All rights reserved.

The feasibility of bomb radiocarbon analysis to support an age-at-length relationship for red abalone, Haliotis rufescens Swainson in northern California

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Leaf, R T; Andrews, A H; Cailliet, G M; Brown, T A

2009-01-07

Analysis of bomb generated radiocarbon ({sup 14}C) changes in a red abalone, Haliotis rufescens Swainson shell was used to investigate age-at-length relationships derived from data from a previous multi-year, multi-site tag-recapture study. Shell carbonate was extracted from four successive growth trajectory locations in a single shell with a length of 251 mm MSL. Extraction locations were based on VBGF predictions and chosen to span the initial rise of the {sup 14}C-bomb pulse that is known to have occurred in surface ocean waters during 1958 {+-} 1 y in the northeast Pacific. The close temporal correspondence of the red abalone sample series to regional {Delta}{sup 14}C records demonstrated the utility of the technique for validating age-at-length relationships for the red abalone. The findings provided support for a mean VBGF derived age of 32 y (range 30 to 33 y) for the specimen; however, the analysis of {sup 14}C data indicated that the specimen could be older.

Mitogen-activated protein kinase 1 from disk abalone (Haliotis discus discus): Roles in early development and immunity-related transcriptional responses.

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Perera, N C N; Godahewa, G I; Lee, Jehee

2016-12-01

Mitogen-activated protein kinase (MAPK) is involved in the regulation of cellular events by mediating signal transduction pathways. MAPK1 is a member of the extracellular-signal regulated kinases (ERKs), playing roles in cell proliferation, differentiation, and development. This is mainly in response to growth factors, mitogens, and many environmental stresses. In the current study, we have characterized the structural features of a homolog of MAPK1 from disk abalone (AbMAPK1). Further, we have unraveled its expressional kinetics against different experimental pathogenic infections or related chemical stimulants. AbMAPK1 harbors a 5' untranslated region (UTR) of 23 bps, a coding sequence of 1104 bps, and a 3' UTR of 448 bp. The putative peptide comprises a predicted molecular mass of 42.2 kDa, with a theoretical pI of 6.28. Based on the in silico analysis, AbMAPK1 possesses two N-glycosylation sites, one S_TK catalytic domain, and a conserved His-Arg-Asp domain (HRD). In addition, a conservative glycine rich ATP-phosphate-binding loop and a threonine-x-tyrosine motif (TEY) important for the autophosphorylation were also identified in the protein. Homology assessment of AbMAPK1 showed several conserved regions, and ark clam (Aplysia californica) showed the highest sequence identity (87.9%). The phylogenetic analysis supported close evolutionary kinship with molluscan orthologs. Constitutive expression of AbMAPK1 was observed in six different tissues of disk abalone, with the highest expression in the digestive tract, followed by the gills and hemocytes. Highest AbMAPK1 mRNA expression level was detected at the trochophore developmental stage, suggesting its role in abalone cell differentiation and proliferation. Significant modulation of AbMAPK1 expression under pathogenic stress suggested its putative involvement in the immune defense mechanism. Copyright © 2016 Elsevier Ltd. All rights reserved.

Detection and localisation of the abalone probiotic Vibrio midae SY9 and its extracellular protease, VmproA, within the digestive tract of the South African abalone, Haliotis midae.

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Robert J Huddy

Full Text Available Probiotics have been widely reported to increase the growth rate of commercially important fish and shellfish by enhancing the digestion of ingested feed through the production of extracellular enzymes such as proteases and alginases. In order to investigate this further, the objective of this study was to localise the bacterial probiont Vibrio midae SY9 and one of the extracellular proteases it produces in the digestive tract of the South African abalone Haliotis midae. This was accomplished by inserting a promotorless gfp gene into the chromosome of the bacterium which was incorporated in an artificial, fishmeal-based abalone feed. In situ histological comparison of abalone fed either a basal diet or the basal diet supplemented with V. midae SY9::Tn10.52 using a cocktail of DNA probes to the gfp gene localised the probiont to the crop/stomach and intestinal regions of the H. midae digestive tract. Generally, the ingested probiotic bacterium occurred in association with feed and particulate matter within the crop/stomach and intestinal regions, as well as adhered to the wall of the crop/stomach. Histological immunohistochemical examination using polyclonal anti-VmproA antibodies localised an extracellular protease produced by V. midae SY9 to the H. midae crop/stomach and intestine where it appeared to be associated with feed and/or other particulate matter in the abalone gut. Thus the data suggests that V. midae SY9 colonises and/or adheres to the mucous lining of the abalone gut. Furthermore, the close association observed between the bacterium, its extracellular protease and ingested feed particles supports the theory that V. midae SY9 elevates in situ digestive enzyme levels and thus enhances feed digestion in farmed abalone.

Detection and localisation of the abalone probiotic Vibrio midae SY9 and its extracellular protease, VmproA, within the digestive tract of the South African abalone, Haliotis midae.

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Huddy, Robert J; Coyne, Vernon E

2014-01-01

Probiotics have been widely reported to increase the growth rate of commercially important fish and shellfish by enhancing the digestion of ingested feed through the production of extracellular enzymes such as proteases and alginases. In order to investigate this further, the objective of this study was to localise the bacterial probiont Vibrio midae SY9 and one of the extracellular proteases it produces in the digestive tract of the South African abalone Haliotis midae. This was accomplished by inserting a promotorless gfp gene into the chromosome of the bacterium which was incorporated in an artificial, fishmeal-based abalone feed. In situ histological comparison of abalone fed either a basal diet or the basal diet supplemented with V. midae SY9::Tn10.52 using a cocktail of DNA probes to the gfp gene localised the probiont to the crop/stomach and intestinal regions of the H. midae digestive tract. Generally, the ingested probiotic bacterium occurred in association with feed and particulate matter within the crop/stomach and intestinal regions, as well as adhered to the wall of the crop/stomach. Histological immunohistochemical examination using polyclonal anti-VmproA antibodies localised an extracellular protease produced by V. midae SY9 to the H. midae crop/stomach and intestine where it appeared to be associated with feed and/or other particulate matter in the abalone gut. Thus the data suggests that V. midae SY9 colonises and/or adheres to the mucous lining of the abalone gut. Furthermore, the close association observed between the bacterium, its extracellular protease and ingested feed particles supports the theory that V. midae SY9 elevates in situ digestive enzyme levels and thus enhances feed digestion in farmed abalone.

In vitro growth of flat aragonite crystals between the layers of the insoluble organic matrix of the abalone Haliotis laevigata

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Gries, Katharina I.; Heinemann, Fabian; Rosenauer, Andreas; Fritz, Monika

2012-11-01

Nacre of abalone shells consists of aragonite platelets and organic material, the so-called organic matrix. During the growth process of the shell the aragonite platelets grow into a scaffold formed by the organic matrix. In this work we tried to mimic this growth process by placing a piece of the insoluble organic matrix (which is a part of the organic matrix) of the abalone Haliotis laevigata in a crystallization device which was flowed through by CaCl2 and NaHCO3 solutions. Using this setup amongst others flat aragonite crystals grow on the insoluble organic matrix. When investigating these crystals in a transmission electron microscope it is possible to recognize similarities to the structure of nacre, like the formation of mineral bridges and growth between layers of the insoluble organic matrix. These similarities are presented in this paper.

Effects of the dietary administration of sodium alginate on the immune responses and disease resistance of Taiwan abalone, Haliotis diversicolor supertexta.

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Cheng, Winton; Yu, Jyun-Sian

2013-03-01

Sodium alginate extracted from brown algae was reported to enhance the immune response and resistance of fish and shrimp. In this study, survival rates of the abalone, Haliotis diversicolor supertexta, against Vibrio parahaemolyticus, and its non-specific immune parameters such as the total haemocyte count (THC), phenoloxidase (PO) activity, respiratory bursts, superoxide dismutase (SOD) activity, phagocytic activity, and clearance efficiency to V. parahaemolyticus by H. diversicolor supertexta were determined when abalone (4.5 ± 0.4 g) were fed diets containing sodium alginate at 0, 1.0, 2.0, and 3.0 g kg⁻¹. Abalone fed a diet containing sodium alginate at 2.0 and 3.0 g kg⁻¹ for 14 days and at 1.0 g kg⁻¹ for 21 days had significantly higher survival rates than those fed the control diet after challenge with V. parahaemolyticus. The relative survival percentages of abalone fed the 1.0, 2.0, and 3.0 g kg⁻¹ sodium alginate-containing diets for 14 and 21 days were 16.1%, 40.0%, and 48.0%, and 63.6%, 27.3% and 22.6%, respectively. The PO activity, respiratory bursts, SOD activity, and phagocytic activity and clearance efficiency of V. parahaemolyticus of abalone fed the sodium alginate-containing diets at 1.0, 2.0, and 3.0 g kg⁻¹ were significantly higher than those of abalone fed the control diet for 14 days. After 21 days, the PO activity, respiratory bursts, SOD activity, and phagocytic activity and clearance efficiency of V. parahaemolyticus by abalone fed the sodium alginate-containing diet at 1.0 g kg⁻¹ were significantly higher than those of abalone fed the other diets. It was concluded that sodium alginate can be used as an immunostimulant for abalone through dietary administration to enhance immune responses of abalone and resistance against V. parahaemolyticus, which were related to the dose and timing of administration. Copyright © 2013 Elsevier Ltd. All rights reserved.

Long-term lead accumulation in abalone (Haliotis spp. ) fed on lead-treated brown algae (Egregia laevigata)

Energy Technology Data Exchange (ETDEWEB)

Stewart, J; Schulz-Baldes, M

1976-01-01

In this study we assessed the amount of lead accumulated in the body of a grazing mollusc by transfer from its algal food in laboratory experiments, and compared these results with the amounts found in naturally occurring molluscs and seaweed. Near La Jolla, California (USA), where the concentration of lead in seawater is probably less than 0.08 ..mu..g 1/sup -1/, most of the naturally occurring Egregia laevigata contains less than 0.4 ..mu..g Pb g/sup -1/ wet weight. The total body masses, without shells, of juvenile Haliotis rufescens fed on this seaweed for 3 to 6 months showed similar concentrations. When, however, E. laevigata is placed for 1 to 6 days in seawater to which lead has been added (0.1 or 1.0 mg 1/sup -1/) both the seaweed and the abalone subsequently fed with it accumulate proportionally larger amounts of lead. After 6 months, young abalone fed on E. laevigata pretreated with 1.0 mg Pb 1/sup -1/ accumulated up to 21 ..mu..g Pb g/sup -1/ wet weight. This amount of lead had no apparent consequences on the growth or activity of the molluscs. Analyses of 6 different organs from adult abalone showed that the lead was selectively concentrated in the digestive gland. In the foot (muscle tissue), which is the part normally consumed by humans, only negligible amounts were found.

ABALONE (HALIOTIS SQUAMATA ANESTHESIA WITH ETHANOL ON GRADING PROCESS

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Fanni N.A.

2018-02-01

Full Text Available An abalone is a group of marine molluscs that have high economic value. To increase abalone production, such cultivation needs to be done considering that abalone production still dominating. However, there are still obstacles in the cultivation which is the high mortality rates on the grading process of juvenile abalone. The fatality occurs due to the traditional grading process by gouging abalone to separate abalone that is attached to the substrate. The use of ethanol as an anesthetic material is expected to minimize the mortality and increase the survival rate of abalone. In this study, the use of ethanol by 30 ml/L as an anesthetic material can separate the abalone from its substrate 447.67 seconds faster than the dose of 10 ml/L. However, the 30 ml/L dose also showed the lowest survival rate of 86.67%. The best recovery test is at 10 ml/L with the fastest recovery time of 143.33 seconds which has a high survival rate of 98.33%. The success of anesthesia by using ethanol in this study can also be done in the grading process of abalone seed and can minimize death due to the traditional grading process.

Molecular evidence for the existence of lipopolysaccharide-induced TNF-alpha factor (LITAF) and Rel/NF-kB pathways in disk abalone (Haliotis discus discus).

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De Zoysa, Mahanama; Nikapitiya, Chamilani; Oh, Chulhong; Whang, Ilson; Lee, Jae-Seong; Jung, Sung-Ju; Choi, Cheol Young; Lee, Jehee

2010-01-01

The lipopolysaccharide-induced TNF-alpha factor (LITAF) and Rel family nuclear factor kappaB (Rel/NF-kB) are two important transcription factors which play major roles in the regulating inflammatory cytokine, apoptosis and immune related genes. Here, we report the discovery of disk abalone LITAF (AbLITAF) and Rel/NF-kB (AbRel/NF-kB) homologues and their immune responses. Full-length cDNA of AbLITAF consists of 441 bp open reading frame (ORF) that translates into putative peptide of 147 aa. Analysis of AbLITAF sequence showed it has characteristic LITAF (Zn(+2)) binding domain with two CXXC motifs. Phylogenetic analysis results further revealed that AbLITAF is a member of LITAF family. AbRel/NF-kB is 584 aa protein that contains several characteristic motifs including Rel homology domain (RHD), Rel protein signature, DNA binding motif, nuclear localization signal (NLS) and transcription factor immunoglobulin - like fold (TIG) similar to their invertebrate and vertebrate counterparts. Tissue specific analysis results showed that both AbLITAF and AbRel/NF-kB mRNA was expressed ubiquitously in all selected tissues in constitutive manner. However, constitutive expression of AbLITAF was higher than AbRel/NF-kB in all tissues except mantle. Upon immune challenge by bacteria (Vibrio alginolyticus, Vibrio parahemolyticus and Lysteria monocytogenes) and viral hemoragic septicemia virus (VHSV), AbLITAF showed the significant up-regulation in gills while AbRel/NF-kB transcription was not change significantly. Based on transcriptional response against immune challenge, we could suggest that regulation of TNF-alpha expression may have occurred mainly by LITAF activation rather than NF-kB in disk abalone. The cumulative data from other molluscs and our data with reference to TNF-alpha, LITAF and Rel/NF-kB from disk abalone provide strong evidence that LITAF and NF-kB are independent pathways likely to occur throughout the Phylum mollusca. 2010 Elsevier Ltd. All rights reserved.

Effects of temperature and salinity on survival, growth and DNA methylation of juvenile Pacific abalone, Haliotis discus hannai Ino

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Kong, Ning; Liu, Xiao; Li, Junyuan; Mu, Wendan; Lian, Jianwu; Xue, Yanjie; Li, Qi

2017-09-01

Temperature and salinity are two of the most potent abiotic factors influencing marine mollusks. In this study, we investigated the individual and combined effects of temperature and salinity on the survival and growth of juvenile Pacific abalone, Haliotis discus hannai Ino, and also examined the DNA methylation alteration that may underpin the phenotypic variation of abalone exposed to different rearing conditions. The single-factor data showed that the suitable ranges of temperature and salinity were 16-28°C at a constant salinity of 32, and 24-40 at a constant temperature of 20°C, respectively. The two-factor data indicated that both survival and growth were significantly affected by temperature, salinity and their interaction. The optimal temperature-salinity combination for juveniles was 23-25°C and 30-36. To explore environment-induced DNA methylation alteration, the methylation-sensitive amplified polymorphism (MSAP) technique was used to analyze the genomic methylation profiles of abalone reared in optimal and adverse conditions. Neither temperature nor salinity induced evident changes in the global methylation level, but 67 and 63 differentially methylated loci were identified in temperature and salinity treatments, respectively. The between-group eigen analysis also showed that both temperature and salinity could induce epigenetic differentiation in H. discus hannai Ino. The results of our study provide optimal rearing conditions for juvenile H. discus hannai Ino, and represent the first step toward revealing the epigenetic regulatory mechanism of abalone in response to thermal and salt stresses.

In vitro Anti-Thrombotic Activity of Extracts from Blacklip Abalone (Haliotis rubra Processing Waste

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Hafiz Ansar Rasul Suleria

2016-12-01

Full Text Available Waste generated from the processing of marine organisms for food represents an underutilized resource that has the potential to provide bioactive molecules with pharmaceutical applications. Some of these molecules have known anti-thrombotic and anti-coagulant activities and are being investigated as alternatives to common anti-thrombotic drugs, like heparin and warfarin that have serious side effects. In the current study, extracts prepared from blacklip abalone (Haliotis rubra processing waste, using food grade enzymes papain and bromelain, were found to contain sulphated polysaccharide with anti-thrombotic activity. Extracts were found to be enriched with sulphated polysaccharides and assessed for anti-thrombotic activity in vitro through heparin cofactor-II (HCII-mediated inhibition of thrombin. More than 60% thrombin inhibition was observed in response to 100 μg/mL sulphated polysaccharides. Anti-thrombotic potential was further assessed as anti-coagulant activity in plasma and blood, using prothrombin time (PT, activated partial thromboplastin time (aPTT, and thromboelastography (TEG. All abalone extracts had significant activity compared with saline control. Anion exchange chromatography was used to separate extracts into fractions with enhanced anti-thrombotic activity, improving HCII-mediated thrombin inhibition, PT and aPTT almost 2-fold. Overall this study identifies an alternative source of anti-thrombotic molecules that can be easily processed offering alternatives to current anti-thrombotic agents like heparin.

In vitro Anti-Thrombotic Activity of Extracts from Blacklip Abalone (Haliotis rubra) Processing Waste.

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Suleria, Hafiz Ansar Rasul; Hines, Barney M; Addepalli, Rama; Chen, Wei; Masci, Paul; Gobe, Glenda; Osborne, Simone A

2016-12-31

Waste generated from the processing of marine organisms for food represents an underutilized resource that has the potential to provide bioactive molecules with pharmaceutical applications. Some of these molecules have known anti-thrombotic and anti-coagulant activities and are being investigated as alternatives to common anti-thrombotic drugs, like heparin and warfarin that have serious side effects. In the current study, extracts prepared from blacklip abalone ( Haliotis rubra ) processing waste, using food grade enzymes papain and bromelain, were found to contain sulphated polysaccharide with anti-thrombotic activity. Extracts were found to be enriched with sulphated polysaccharides and assessed for anti-thrombotic activity in vitro through heparin cofactor-II (HCII)-mediated inhibition of thrombin. More than 60% thrombin inhibition was observed in response to 100 μg/mL sulphated polysaccharides. Anti-thrombotic potential was further assessed as anti-coagulant activity in plasma and blood, using prothrombin time (PT), activated partial thromboplastin time (aPTT), and thromboelastography (TEG). All abalone extracts had significant activity compared with saline control. Anion exchange chromatography was used to separate extracts into fractions with enhanced anti-thrombotic activity, improving HCII-mediated thrombin inhibition, PT and aPTT almost 2-fold. Overall this study identifies an alternative source of anti-thrombotic molecules that can be easily processed offering alternatives to current anti-thrombotic agents like heparin.

Feeding, growth, and survival of post-larval abalone Haliotis asinina on different benthic diatoms

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Emmanuel C. Capinpin, Jr.

2007-12-01

Full Text Available The feeding behavior, digestive efficiency, growth, and survival of post-larval abalone Haliotis asininafed with 5 species of locally isolated benthic diatom strains (Navicula mollis, N. ramosissima, Stauroneissp., Pleurosigma sp., and Cocconeis sp. were examined in the laboratory. Two 15-day feeding trialsusing 1 mm post-larvae were conducted. No significant differences were observed in sizes of post-larvalabalone after 15 days in all diatom treatments (P>0.05. However, in both trials, Cocconeis sp. resulted inhigh survival rates (88.9±5.6% and 80.0±20.0% for Trials 1 and 2, respectively. Cocconeis sp. wasefficiently digested by post-larval abalone, with most of the cells being ruptured during ingestion and/orpassage through the gut. One diatom strain, Pleurosigma sp., resulted to a high survival but producedthe slowest growth rate (<10 ìm.d-1 SL. It was probably not ingested easily during the experiment due toits large size or mobility. For the other diatom strains, N. mollis and N. ramosissima, most cells passedthrough the gut with the cells left intact. Stauroneis sp. is highly digestible, but did not result to highsurvival, although the remaining live post-larval abalone fed on this diatom as well as on N. mollis grewfaster during the second week of both feeding trials. N. ramosissima resulted to poorest survival rate(<10% due to its poor digestibility. Only Cocconeis sp. showed a fairly high growth rate, digestionefficiency, and survival rate. N. mollis which gave a fairly high survival rate and Stauroneis may be addedtowards the later stages of post-larval rearing as well as other large diatoms. The digestion efficiency ofdiatom strains is considered an important factor determining its dietary value, but other factors may alsobe important such as volume contents, biochemical composition, and other physical characteristics.

Involvement of clip-domain serine protease in the anti-Vibrio immune response of abalone (Haliotis discus hannai)-Molecular cloning, characterization and functional analysis.

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Hu, Jian-Jian; Chen, Yu-Lei; Duan, Xue-Kun; Jin, Teng-Chuan; Li, Yue; Zhang, Ling-Jing; Liu, Guang-Ming; Cao, Min-Jie

2018-01-01

Vibrio parahemolyticus (V. parahemolyticus) is a major pathogen for abalone, an important economical shellfish in coastal area of China. There is little known about the abalone innate immune system against pathogen infection. Clip-domain serine proteases (cSPs) are increasingly recognized to play important roles in host immune defense in invertebrates. In this study, we cloned a cSP (Hdh-cSP) from abalone (Haliotis discus hannai). We found out that Hdh-cSP was widely expressed in multiple tissues of abalone, with highest level in the immune-like organ, hepatopancreas. V. parahemolyticus infection induced significantly elevated expression of Hdh-cSP in addition to better-characterized innate immune component genes including Rel/NF-κB, allograft inflammatory factor (ALInFa), macrophage expressed protein (MEP) and caspase-8. Importantly, the silencing of Hdh-cSP reduced the expression of these genes, suggesting that Hdh-cSP was an upstream regulatory factor in V. parahemolyticus infection. Further analysis showed that apoptosis of hemocytes was inhibited when the transcription of Hdh-cSP was knocked down, suggesting that Hdh-cSP participated in cell apoptosis by regulation of caspase 8 expression in V. parahemolyticus infection. Therefore, our study established an important role of cSP in the innate immunity against V. parahemolyticus infection in abalone. Copyright © 2017 Elsevier Ltd. All rights reserved.

First attempts to cryopreserve red abalone (Haliotis rufescens oocytes

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Ramírez Torrez, A.

2015-01-01

Full Text Available Overall, few advances in the cryopreservation of complex cells such as oocytes, embryo or tissue have been registered and in less quantity have been reported for aquatic species. Abalone has high economic interest worldwide and the conservation of abalone germplasm may help to enhance its culture and develop repopulation programs. In this work, we reported the cytotoxic effect of two concentration of trehalose (0.2 and 0.4 M on red abalone oocytes incubated for 10, 15 and 20 min. Also, we reported the cryopreservation of red abalone oocytes using a 3-steps cryopreservation protocol and 5 thawing protocols. Significant differences on cytotoxic effect were found (p<0.01. However, none of the cryoprotectant was optimum to cryopreserve red abalone oocyte. In conclusion, it is necessary to find an appropriate method to dehydrate or make the cryoprotectant penetrate on the abalone oocyte before proceeding to cryopreservation.

Identification of normalization factors for quantitative real-time RT-PCR analysis of gene expression in Pacific abalone Haliotis discus hannai

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Qiu, Reng; Sun, Boguang; Fang, Shasha; Sun, Li; Liu, Xiao

2013-03-01

Quantitative real-time reverse transcription-polymerase chain reaction (qRT-PCR) is widely used in studies of gene expression. In most of these studies, housekeeping genes are used as internal references without validation. To identify appropriate reference genes for qRT-PCR in Pacific abalone Haliotis discus hannai, we examined the transcription stability of six housekeeping genes in abalone tissues in the presence and absence of bacterial infection. For this purpose, abalone were infected with the bacterial pathogen Vibrio anguillarum for 12 h and 48 h. The mRNA levels of the housekeeping genes in five tissues (digestive glands, foot muscle, gill, hemocyte, and mantle) were determined by qRT-PCR. The PCR data was subsequently analyzed with the geNorm and NormFinder algorithms. The results show that in the absence of bacterial infection, elongation factor-1-alpha and beta-actin were the most stably expressed genes in all tissues, and thus are suitable as cross-tissue type normalization factors. However, we did not identify any universal reference genes post infection because the most stable genes varied between tissue types. Furthermore, for most tissues, the optimal reference genes identified by both algorithms at 12 h and 48 h post-infection differed. These results indicate that bacterial infection induced significant changes in the expression of abalone housekeeping genes in a manner that is dependent on tissue type and duration of infection. As a result, different normalization factors must be used for different tissues at different infection points.

Manipulations of adult density and juvenile habitat quality in Northern Abalone stock restoration

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DeFreitas, Bart Andre

2005-01-01

Wild abalone populations throughout the world have declined dramatically over the past 40 years due primarily to market demands for the mollusc's edible foot. Northern abalone (Haliotis kamtschatkana), the only abalone species occurring in British Columbia (B.C.), is widely thought to be threatened by potential population collapse as a result of low adult densities that impair reproductive potential. This study examined the hypothesis that the abundance of wild northern abalone populations ar...

Tributyltin toxicity in abalone (Haliotis diversicolor supertexta) assessed by antioxidant enzyme activity, metabolic response, and histopathology.

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Zhou, Jin; Zhu, Xiao-shan; Cai, Zhong-hua

2010-11-15

A toxicity test was performed to investigate the possible harmful effects of tributyltin (TBT) on abalone (Haliotis diversicolor supertexta). Animals were exposed to TBT in a range of environmentally relevant concentrations (2, 10 and 50 ng/L) for 30 days under laboratory conditions. TBT-free conditions were used as control treatments. The activity of antioxidant enzymes superoxide dismutase (SOD) and peroxidase (POD), and malondialdehyde (MDA), along with levels of haemolymph metabolites, and hepatopancreas histopathology were analyzed. The results showed that TBT decreased SOD activity, and increased POD level and MDA production in a dose-dependent way, indicating that oxidative injury was induced by TBT. Haemolymph metabolite measurements showed that TBT increased alanine and glutamate levels, and decreased glucose content, which suggested perturbation of energy metabolism. Elevated levels of acetate and pyruvate in the haemolymph indicated partial alteration of lipid metabolism. A decrease in lactate and an increase in succinate, an intermediate of the tricarboxylic acid (TCA) cycle, indicated disturbance of amino acid metabolism. Hepatopancreas tissues also exhibited inflammatory responses characterized by histopathological changes such as cell swelling, granular degeneration, and inflammation. Taken together, these results demonstrated that TBT was a potential toxin with a variety of deleterious effects on abalone. Copyright © 2010 Elsevier B.V. All rights reserved.

Abalone farm discharges the withering syndrome pathogen into the wild

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Kevin eLafferty

2013-12-01

Full Text Available An intracellular bacterium Candidatus Xenohaliotis californiensis, also called Withering-Syndrome Rickettsia-Like Organism (WS-RLO, is the cause of mass mortalities that are the chief reason for endangerment of black abalone (Haliotis cracherodii. Using a real-time PCR assay, we found that a shore-based abalone farm in Santa Barbara, California, discharged WS-RLO DNA into the ocean. Several other shore-based abalone farms discharge effluent into critical habitat for black abalone in California and this might affect the recovery of wild black abalone. Existing regulatory frameworks exist that could help protect wild species from pathogens released from shore-based aquaculture.

Habitat Preferences of Juvenile Abalone (Haliotis mariae Wood, 1828 Along the Dhofar Coast of Oman and Implications for Conservation

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Schalk Willem Petrus de Waal

2012-01-01

Full Text Available Surveys were conducted along the eastern Dhofar coast of Oman to investigate densities and habitat preferences of juvenile Haliotis mariae ( 50 cm Ø, respectively. B values were highest for urchins (6 times that for small boulders, and for boulders <50 cm Ø. B values for boulder habitats decreased as boulder size increased. Urchin utilisation by juvenile abalone as shelter ranged between geographic areas from a minimum of 15.5% to a maximum of 47.6%. The proportion of total habitat that is preferred by more than 97% of juvenile abalone found, including urchins and boulders < 50 cm Ø, comprises 29% of surveyed substratum. While the role urchins play on wild juvenile H. mariae has not proved vital, it is definitely significant. Although juvenile densities are low and are not currently limited by the availability of suitable habitat, it is crucial to identify and conserve those microhabitats that support recruitment of H. mariae. The abundance of these areas should be among the criteria used in selecting protected conservation areas.

Feeding preferences and the nutritional value of tropical algae for the abalone Haliotis asinina.

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Alex R Angell

Full Text Available Understanding the feeding preferences of abalone (high-value marine herbivores is integral to new species development in aquaculture because of the expected link between preference and performance. Performance relates directly to the nutritional value of algae--or any feedstock--which in turn is driven by the amino acid content and profile, and specifically the content of the limiting essential amino acids. However, the relationship between feeding preferences, consumption and amino acid content of algae have rarely been simultaneously investigated for abalone, and never for the emerging target species Haliotis asinina. Here we found that the tropical H. asinina had strong and consistent preferences for the red alga Hypnea pannosa and the green alga Ulva flexuosa, but no overarching relationship between protein content (sum of amino acids and preference existed. For example, preferred Hypnea and Ulva had distinctly different protein contents (12.64 vs. 2.99 g 100 g(-1 and the protein-rich Asparagopsis taxiformis (>15 g 100 g(-1 of dry weight was one of the least preferred algae. The limiting amino acid in all algae was methionine, followed by histidine or lysine. Furthermore we demonstrated that preferences can largely be removed using carrageenan as a binder for dried alga, most likely acting as a feeding attractant or stimulant. The apparent decoupling between feeding preference and algal nutritive values may be due to a trade off between nutritive values and grazing deterrence associated with physical and chemical properties.

Feeding Preferences and the Nutritional Value of Tropical Algae for the Abalone Haliotis asinina

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Angell, Alex R.; Pirozzi, Igor; de Nys, Rocky; Paul, Nicholas A.

2012-01-01

Understanding the feeding preferences of abalone (high-value marine herbivores) is integral to new species development in aquaculture because of the expected link between preference and performance. Performance relates directly to the nutritional value of algae – or any feedstock – which in turn is driven by the amino acid content and profile, and specifically the content of the limiting essential amino acids. However, the relationship between feeding preferences, consumption and amino acid content of algae have rarely been simultaneously investigated for abalone, and never for the emerging target species Haliotis asinina. Here we found that the tropical H. asinina had strong and consistent preferences for the red alga Hypnea pannosa and the green alga Ulva flexuosa, but no overarching relationship between protein content (sum of amino acids) and preference existed. For example, preferred Hypnea and Ulva had distinctly different protein contents (12.64 vs. 2.99 g 100 g−1) and the protein-rich Asparagopsis taxiformis (>15 g 100 g−1 of dry weight) was one of the least preferred algae. The limiting amino acid in all algae was methionine, followed by histidine or lysine. Furthermore we demonstrated that preferences can largely be removed using carrageenan as a binder for dried alga, most likely acting as a feeding attractant or stimulant. The apparent decoupling between feeding preference and algal nutritive values may be due to a trade off between nutritive values and grazing deterrence associated with physical and chemical properties. PMID:22719967

Cathepsin L is an immune-related protein in Pacific abalone (Haliotis discus hannai)--Purification and characterization.

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Shen, Jian-Dong; Cai, Qiu-Feng; Yan, Long-Jie; Du, Cui-Hong; Liu, Guang-Ming; Su, Wen-Jin; Ke, Caihuan; Cao, Min-Jie

2015-12-01

Cathepsin L, an immune-related protein, was purified from the hepatopancreas of Pacific abalone (Haliotis discus hannai) by ammonium sulfate precipitation and column chromatographies of SP-Sepharose and Sephacryl S-200 HR. Purified cathepsin L appeared as two bands with molecular masses of 28.0 and 28.5 kDa (namely cathepsin La and Lb) on SDS-PAGE under reducing conditions, suggesting that it is a glycoprotein. Peptide mass fingerprinting (PMF) analysis revealed that peptide fragments of 95 amino acid residues was high similarity to cathepsin L of pearl oyster (Pinctada fucata). The optimal temperature and pH of cathepsin L were 35 °C and pH 5.5. Cathepsin L was particularly inhibited by cysteine proteinase inhibitors of E-64 and leupeptin, while it was activated by metalloproteinase inhibitors EDTA and EGTA. The full-length cathepsin L cDNA was further cloned from the hepatopancreas by rapid PCR amplification of cDNA ends (RACE). The open reading frame of the enzyme was 981 bp, encoding 327 amino acid residues, with a conserved catalytic triad (Cys134, His273 and Asn293), a potential N-glycosylation site and conserved ERFNIN, GNYD, and GCGG motifs, which are characteristics of cathepsin L. Western blot and proteinase activity analysis revealed that the expression and enzyme activity of cathepsin L were significantly up-regulated in hepatopancreas at 8 h following Vibrio parahaemolyticus infection, demonstrating that cathepsin L is involved in the innate immune system of abalone. Our present study for the first time reported the purification, characterization, molecular cloning, and tissue expression of cathepsin L in abalone. Copyright © 2015 Elsevier Ltd. All rights reserved.

Abalone farm discharges the withering syndrome pathogen into the wild.

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Lafferty, Kevin D; Ben-Horin, Tal

2013-01-01

An intracellular bacterium Candidatus Xenohaliotis californiensis, also called Withering-Syndrome Rickettsia-Like Organism (WS-RLO), is the cause of mass mortalities that are the chief reason for endangerment of black abalone (Haliotis cracherodii). Using a real-time PCR assay, we found that a shore-based abalone farm (AF) in Santa Barbara, CA, USA discharged WS-RLO DNA into the ocean. Several other shore-based AFs discharge effluent into critical habitat for black abalone in California and this might affect the recovery of wild black abalone. Existing regulatory frameworks exist that could help protect wild species from pathogens released from shore-based aquaculture.

Transcriptome-Wide Single Nucleotide Polymorphisms (SNPs for Abalone (Haliotis midae: Validation and Application Using GoldenGate Medium-Throughput Genotyping Assays

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Rouvay Roodt-Wilding

2013-09-01

Full Text Available Haliotis midae is one of the most valuable commercial abalone species in the world, but is highly vulnerable, due to exploitation, habitat destruction and predation. In order to preserve wild and cultured stocks, genetic management and improvement of the species has become crucial. Fundamental to this is the availability and employment of molecular markers, such as microsatellites and Single Nucleotide Polymorphisms (SNPs . Transcriptome sequences generated through sequencing-by-synthesis technology were utilized for the in vitro and in silico identification of 505 putative SNPs from a total of 316 selected contigs. A subset of 234 SNPs were further validated and characterized in wild and cultured abalone using two Illumina GoldenGate genotyping assays. Combined with VeraCode technology, this genotyping platform yielded a 65%−69% conversion rate (percentage polymorphic markers with a global genotyping success rate of 76%−85% and provided a viable means for validating SNP markers in a non-model species. The utility of 31 of the validated SNPs in population structure analysis was confirmed, while a large number of SNPs (174 were shown to be informative and are, thus, good candidates for linkage map construction. The non-synonymous SNPs (50 located in coding regions of genes that showed similarities with known proteins will also be useful for genetic applications, such as the marker-assisted selection of genes of relevance to abalone aquaculture.

Transcriptome-wide single nucleotide polymorphisms (SNPs) for abalone (Haliotis midae): validation and application using GoldenGate medium-throughput genotyping assays.

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Bester-Van Der Merwe, Aletta; Blaauw, Sonja; Du Plessis, Jana; Roodt-Wilding, Rouvay

2013-09-23

Haliotis midae is one of the most valuable commercial abalone species in the world, but is highly vulnerable, due to exploitation, habitat destruction and predation. In order to preserve wild and cultured stocks, genetic management and improvement of the species has become crucial. Fundamental to this is the availability and employment of molecular markers, such as microsatellites and single nucleotide (SNPs). Transcriptome sequences generated through sequencing-by-synthesis technology were utilized for the in vitro and in silico identification of 505 putative SNPs from a total of 316 selected contigs. A subset of 234 SNPs were further validated and characterized in wild and cultured abalone using two Illumina GoldenGate genotyping assays. Combined with VeraCode technology, this genotyping platform yielded a 65%-69% conversion rate (percentage polymorphic markers) with a global genotyping success rate of 76%-85% and provided a viable means for validating SNP markers in a non-model species. The utility of 31 of the validated SNPs in population structure analysis was confirmed, while a large number of SNPs (174) were shown to be informative and are, thus, good candidates for linkage map construction. The non-synonymous SNPs (50) located in coding regions of genes that showed similarities with known proteins will also be useful for genetic applications, such as the marker-assisted selection of genes of relevance to abalone aquaculture.

Acclimation-dependent expression of heat shock protein 70 in Pacific abalone ( Haliotis discus hannai Ino) and its acute response to thermal exposure

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Li, Jiaqi; He, Qingguo; Sun, Hui; Liu, Xiao

2012-01-01

Heat shock protein 70 (Hsp70) is one important member of heat shock protein (Hsp) family that is responsible for various stresses, especially thermal stress. Here we examined the response of Hsp70 gene to both chronic and acute thermal exposure in Pacific abalone ( Haliotis discus hannai Ino). For the chronic exposure, abalones were maintained at 8, 12, 20, and 30°C for four months and their mRNA levels were measured. The highest mRNA level of Hsp70 gene relative to actin gene was detected in the 30°C-acclimated group, followed by the 8°C-acclimated group and then the 12°C- and 20°C-acclimated groups. After the long-term acclimation, gills from each of the above acclimation groups were dissected and exposed to different temperatures between 8°C and 38°C for 30 min. Hsp70 expression in gills acclimated to different temperatures responded differentially to the same temperature exposure. The incubation temperature that induced maximum Hsp70 mRNA expression was higher in the higher temperature acclimation groups than lower temperature groups. Pacific abalones could alter the expression pattern of Hsp70 gene according to environmental thermal conditions, through which they deal with the stress of thermal variations.

Innate resistance of New Zealand paua to abalone viral ganglioneuritis.

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Corbeil, Serge; McColl, Kenneth A; Williams, Lynette M; Slater, Joanne; Crane, Mark St J

2017-06-01

The susceptibility of New Zealand paua (Haliotis iris) to infection by abalone herpesvirus (Haliotid herpesvirus 1; HaHV) and to the disease abalone viral ganglioneuritis (AVG) was determined. Infection challenges performed by intra-muscular injection and by immersion in infectious water containing HaHV demonstrated that New Zealand paua were highly resistant to infection by Haliotid herpesvirus 1 and were fully resistant to the disease AVG. Copyright © 2017 Elsevier Inc. All rights reserved.

Dietary ascorbic acid modulates the expression profile of stress protein genes in hepatopancreas of adult Pacific abalone Haliotis discus hannai Ino.

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Wu, Chenglong; Wang, Jia; Xu, Wei; Zhang, Wenbing; Mai, Kangsen

2014-12-01

This study was conducted to investigate the effects of dietary ascorbic acid (AA) on transcriptional expression patterns of antioxidant proteins, heat shock proteins (HSP) and nuclear factor kappa B (NF-κB) in the hepatopancreas of Pacific abalone Haliotis discus hannai Ino (initial average length: 84.36 ± 0.24 mm) using real-time quantitative PCR assays. L-ascorbyl-2-molyphosphate (LAMP) was added to the basal diet to formulate four experimental diets containing 0.0, 70.3, 829.8 and 4967.5 mg AA equivalent kg(-1) diets, respectively. Each diet was fed to triplicate groups of adult abalone in acrylic tanks (200 L) in a flow-through seawater system. Each tank was stocked with 15 abalone. Animals were fed once daily (17:00) to apparent satiation for 24 weeks. The results showed that the dietary AA (70.3 mg kg(-1)) could significantly up-regulate the expression levels of Cu/Zn superoxide dismutase (SOD), catalase (CAT), glutathione-S-transferase (GST), feritin (FT) and heat shock protein 26 (HSP26) in the hepatopancreas of abalone in this treatment compared to the controls. However, the expression levels of Mn-SOD, glutathione peroxidase (GPX), thioredoxin peroxidase (TPx), selenium-binding protein (SEBP), HSP70 and HSP90 were significantly down-regulated. Compared with those in the group with 70.3 mg kg(-1) dietary AA, the expression levels of CAT, GST and HSP26 were decreased in abalone fed with very high dietary AA (4967.5 mg kg(-1)). In addition, significant up-regulations of expression levels of Mn-SOD, GPX, TPx, SEBP, FT, HSP70, HSP90 and NF-κB were observed in abalone fed with apparently excessive dietary AA (829.8 and 4967.5 mg kg(-1)) as compared to those fed 70.3 mg kg(-1) dietary AA. These findings showed that dietary AA influenced the expression levels of antioxidant proteins, heat shock proteins and NF-κB in the hepatopancreas of abalone at transcriptional level. Levels of dietary AA that appeared adequate (70.3 mg kg(-1)) reduced the oxidative stress

Genetic Characterization of Five Hatchery Populations of the Pacific Abalone (Haliotis discus hannai Using Microsatellite Markers

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Jeong-In Myeong

2011-07-01

Full Text Available The Pacific abalone, Haliotis discus hannai, is a popular food in Eastern Asia. Aquacultural production of this species has increased because of recent resource declines, the growing consumption, and ongoing government-operated stock release programs. Therefore, the genetic characterization of hatchery populations is necessary to maintain the genetic diversity of this species and to develop more effective aquaculture practices. We analyzed the genetic structures of five cultured populations in Korea using six microsatellite markers. The number of alleles per locus ranged from 15 to 64, with an average of 23.5. The mean observed and expected heterozygosities were 0.797 and 0.904, respectively. The inbreeding coefficient FIS ranged from 0.054 to 0.184 (mean FIS = 0.121 ± 0.056. The genetic differentiation across all populations was low but significant (overall FST = 0.009, P < 0.01. Pairwise multilocus FST tests, estimates of genetic distance, and phylogenetic and principal component analyses did not show a consistent relationship between geographic and genetic distances. These results could reflect extensive aquaculture, the exchange of breeds and eggs between hatcheries and/or genetic drift due to intensive breeding practices. Thus, for optimal resource management, the genetic variation of hatchery stocks should be monitored and inbreeding controlled within the abalone stocks that are being released every year. This genetic information will be useful for the management of both H. discus hannai fisheries and the aquaculture industry.

Influences of DMP on the fertilization process and subsequent embryogenesis of abalone (Haliotis diversicolor supertexta by gametes exposure.

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Jin Zhou

Full Text Available Di-methyl phthalate (DMP, a typical endocrine disrupting chemical (EDC, is ubiquitously distributed in aquatic environments; yet studies regarding its impact on gametes and the resulting effects on embryogenesis in marine gastropods are relatively scarce. In this study, the influences of DMP on the gametes and subsequent developmental process of abalone (Haliotis diversicolor supertexta, a representative marine benthic gastropod were assessed. Newborn abalone eggs and sperm were exposed separately to different DMP concentrations (1, 10 or 100 ppb for 60 min. At the end-point of exposure, the DMP-treated eggs and sperm were collected for analysis of their ultra-structures, ATPase activities and total lipid levels, and the fertilized gametes (embryos were collected to monitor related reproductive parameters (fertilization rate, abnormal development rate and hatching success rate. Treatment with DMP did not significantly alter the structure or total lipid content of eggs at any of the doses tested. Hatching failures and morphological abnormalities were only observed with the highest dose of DMP (100 ppb. However, DMP exposure did suppress sperm ATPase activities and affect the morphological character of their mitochondria. DMP-treated sperm exhibited dose-dependent decreases in fertilization efficiency, morphogenesis and hatchability. Relatively obvious toxicological effects were observed when both sperm and eggs were exposed to DMP. Furthermore, RT-PCR results indicate that treatment of gametes with DMP changed the expression patterns of physiologically-regulated genes (cyp3a, 17β-HSD-11 and 17β-HSD-12 in subsequent embryogenesis. Taken together, this study proofed that pre-fertilization exposure of abalone eggs, sperm or both to DMP adversely affects the fertilization process and subsequent embryogenesis.

Potential Response to Selection of HSP70 as a Component of Innate Immunity in the Abalone Haliotis rufescens

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Brokordt, Katherina B.; González, Roxana C.; Farías, William J.; Winkler, Federico M.

2015-01-01

Assessing components of the immune system may reflect disease resistance. In some invertebrates, heat shock proteins (HSPs) are immune effectors and have been described as potent activators of the innate immune response. Several diseases have become a threat to abalone farming worldwide; therefore, increasing disease resistance is considered to be a long-term goal for breeding programs. A trait will respond to selection only if it is determined partially by additive genetic variation. The aim of this study was to estimate the heritability (h 2) and the additive genetic coefficient of variation (CV A) of HSP70 as a component of innate immunity of the abalone Haliotis rufescens, in order to assess its potential response to selection. These genetic components were estimated for the variations in the intracellular (in haemocytes) and extracellular (serum) protein levels of HSP70 in response to an immunostimulant agent in 60 full-sib families of H. rufescens. Levels of HSP70 were measured twice in the same individuals, first when they were young and again when they were pre-harvest adults, to estimate the repeatability (R), the h 2 and the potential response to selection of these traits at these life stages. High HSP70 levels were observed in abalones subjected to immunostimulation in both the intracellular and extracellular haemolymph fractions. This is the first time that changes in serum levels of HSP70 have been reported in response to an immune challenge in molluscs. HSP70 levels in both fractions and at both ages showed low h 2 and R, with values that were not significantly different from zero. However, HSP70 induced levels had a CV A of 13.3–16.2% in young adults and of 2.7–8.1% in pre-harvest adults. Thus, despite its low h 2, HSP70 synthesis in response to an immune challenge in red abalone has the potential to evolve through selection because of its large phenotypic variation and the presence of additive genetic variance, especially in young animals. PMID

Potential Response to Selection of HSP70 as a Component of Innate Immunity in the Abalone Haliotis rufescens.

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Katherina B Brokordt

Full Text Available Assessing components of the immune system may reflect disease resistance. In some invertebrates, heat shock proteins (HSPs are immune effectors and have been described as potent activators of the innate immune response. Several diseases have become a threat to abalone farming worldwide; therefore, increasing disease resistance is considered to be a long-term goal for breeding programs. A trait will respond to selection only if it is determined partially by additive genetic variation. The aim of this study was to estimate the heritability (h2 and the additive genetic coefficient of variation (CVA of HSP70 as a component of innate immunity of the abalone Haliotis rufescens, in order to assess its potential response to selection. These genetic components were estimated for the variations in the intracellular (in haemocytes and extracellular (serum protein levels of HSP70 in response to an immunostimulant agent in 60 full-sib families of H. rufescens. Levels of HSP70 were measured twice in the same individuals, first when they were young and again when they were pre-harvest adults, to estimate the repeatability (R, the h2 and the potential response to selection of these traits at these life stages. High HSP70 levels were observed in abalones subjected to immunostimulation in both the intracellular and extracellular haemolymph fractions. This is the first time that changes in serum levels of HSP70 have been reported in response to an immune challenge in molluscs. HSP70 levels in both fractions and at both ages showed low h2 and R, with values that were not significantly different from zero. However, HSP70 induced levels had a CVA of 13.3-16.2% in young adults and of 2.7-8.1% in pre-harvest adults. Thus, despite its low h2, HSP70 synthesis in response to an immune challenge in red abalone has the potential to evolve through selection because of its large phenotypic variation and the presence of additive genetic variance, especially in young animals.

Effects of ocean acidification with pCO2 diurnal fluctuations on survival and larval shell formation of Ezo abalone, Haliotis discus hannai.

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Onitsuka, Toshihiro; Takami, Hideki; Muraoka, Daisuke; Matsumoto, Yukio; Nakatsubo, Ayumi; Kimura, Ryo; Ono, Tsuneo; Nojiri, Yukihiro

2018-03-01

This study assessed the effects of constant and diurnally fluctuating pCO 2 on development and shell formation of larval abalone Haliotis discus hannai. The larvae was exposed to different pCO 2 conditions; constant [450, 800, or 1200 μatm in the first experiment (Exp. I), 450 or 780 μatm in the second experiment (Exp. II)] or diurnally fluctuating pCO 2 (800 ± 400 or 1200 ± 400 μatm in Exp. I, 450 ± 80, 780 ± 200 or 780 ± 400 μatm in Exp. II). Mortality, malformation rates or shell length of larval abalone were not significantly different among the 450, 800, and 800 ± 400 μatm pCO 2 treatments. Meanwhile, significantly higher malformation rates and smaller shells were detected in the 1200 and 1200 ± 400 μatm pCO 2 treatments than in the 450 μatm pCO 2 treatment. The negative impacts were greater in the 1200 ± 400 μatm than in the 1200 μatm. Shell length and malformation rate of larval abalone were related with aragonite saturation state (Ω-aragonite) in experimental seawater, and greatly changed around 1.1 of Ω-aragonite which corresponded to 1000-1300 μatm pCO 2 . These results indicate that there is a pCO 2 threshold associated with Ω-aragonite in the seawater, and that pCO 2 fluctuations produce additional negative impacts on abalone when above the threshold. Clear relationships were detected between abalone fitness and the integrated pCO 2 value over the threshold, indicating that the effects of OA on development and shell formation of larval abalone can be determined by intensity and time of exposure to pCO 2 over the threshold. Copyright © 2017 Elsevier Ltd. All rights reserved.

Anti-allergic effects of a nonameric peptide isolated from the intestine gastrointestinal digests of abalone (Haliotis discus hannai) in activated HMC-1 human mast cells.

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Ko, Seok-Chun; Lee, Dae-Sung; Park, Won Sun; Yoo, Jong Su; Yim, Mi-Jin; Qian, Zhong-Ji; Lee, Chang-Min; Oh, Junghwan; Jung, Won-Kyo; Choi, Il-Whan

2016-01-01

The aim of the present study was to examine whether the intestine gastrointestinal (GI) digests of abalone [Haliotis discus hannai (H. discus hannai)] modulate inflammatory responses and to elucidate the mechanisms involved. The GI digests of the abalone intestines were fractionated into fractions I (>10 kDa), II (5-10 kDa) and Ⅲ (abalone intestine GI digests (AIGIDs), fraction Ⅲ inhibited the passive cutaneous anaphylaxis (PCA) reaction in mice. Subsequently, a bioactive peptide [abalone intestine GI digest peptide (AIGIDP)] isolated from fraction Ⅲ was determined to be 1175.2 Da, and the amino acid sequence was found to be PFNQGTFAS. We noted that the purified nonameric peptide (AIGIDP) attenuated the phorbol‑12‑myristate 13-acetate plus calcium ionophore A23187 (PMACI)-induced histamine release and the production of pro-inflammatory cytokines, such as tumor necrosis factor-α (TNF-α), interleukin (IL)-1β and IL-6 in human mast cells (HMC-1 cells). In addition, we also noted that AIGIDP inhibited the PMACI‑induced activation of nuclear factor‑κB (NF-κB) by suppressing IκBα phosphorylation and that it suppressed the production of cytokines by decreasing the phosphorylation of JNK. The findings of our study indicate that AIGIDP exerts a modulatory, anti-allergic effect on mast cell-mediated inflammatory diseases.

Effects of tributyltin and benzo[a]pyrene on the immune-associated activities of hemocytes and recovery responses in the gastropod abalone, Haliotis diversicolor.

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Gopalakrishnan, Singaram; Huang, Wei-Bin; Wang, Qiang-Wei; Wu, Man-Li; Liu, Jie; Wang, Ke-Jian

2011-08-01

Our previous study reports that short-term exposure to sublethal concentrations of benzo[a]pyrene (BaP) induces immunomodulation in the gastropod abalone, Haliotis diversicolor. In the present study, it was further observed that long-term chronic exposure to sublethal concentrations of BaP modulated the immunocompetence of abalones in terms of the change in activity of the antioxidant and immune associated parameters tested. In addition, the effect of tributyltin (TBT), another important genotoxicant in the aquatic environment, was investigated. Exposure of abalones to sublethal concentrations of TBT and BaP for 21 days resulted in significant decrease of total hemocyte count, phagocytosis, membrane stability and lysozyme activity. Conversely induction of extra and intra cellular superoxide generation, nitric oxide, nitric oxide synthase and myeloperoxidase activity was present when the abalones were exposed to TBT and BaP. Most of the immune associated parameters tested showed clear time dependent response to both toxicants. Within 14 days after the 21 day exposure to BaP, recovery was observed as evidenced by most of the parameters returning to their normal level. However, no recovery was observed within 14 days after the 21 day exposure to TBT as evidenced by continued elevation of intra cellular superoxide and nitrite production and decrease in THC, membrane stability and lysozyme activity. This suggested a prolonged TBT-induced impact on the immune reaction and possibly more damage than that caused by BaP. Overall the results suggest that chronic exposure to sublethal concentrations of TBT or BaP causes modulations in the immunocompetence of abalones with most of the immune associated parameters tested being stimulated, and this might be harmful to the host. Copyright © 2011 Elsevier Inc. All rights reserved.

Application of novel polymorphic microsatellite loci identified in the Korean Pacific Abalone (Haliotis diversicolor supertexta (Haliotidae)) in the genetic characterization of wild and released populations.

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An, Hye Suck; Lee, Jang Wook; Hong, Seong Wan

2012-01-01

The small abalone, Haliotis diversicolor supertexta, of the family Haliotidae, is one of the most important species of marine shellfish in eastern Asia. Over the past few decades, this species has drastically declined in Korea. Thus, hatchery-bred seeds have been released into natural coastal areas to compensate for the reduced fishery resources. However, information on the genetic background of the small abalone is scarce. In this study, 20 polymorphic microsatellite DNA markers were identified using next-generation sequencing techniques and used to compare allelic variation between wild and released abalone populations in Korea. Using high-throughput genomic sequencing, a total of 1516 (2.26%; average length of 385 bp) reads containing simple sequence repeats were obtained from 86,011 raw reads. Among the 99 loci screened, 28 amplified successfully, and 20 were polymorphic. When comparing allelic variation between wild and released abalone populations, a total of 243 different alleles were observed, with 18.7 alleles per locus. High genetic diversity (mean heterozygosity = 0.81; mean allelic number = 15.5) was observed in both populations. A statistical analysis of the fixation index (F(ST)) and analysis of molecular variance (AMOVA) indicated limited genetic differences between the two populations (F(ST) = 0.002, p > 0.05). Although no significant reductions in the genetic diversity were found in the released population compared with the wild population (p > 0.05), the genetic diversity parameters revealed that the seeds released for stock abundance had a different genetic composition. These differences are likely a result of hatchery selection and inbreeding. Additionally, all the primer pair sets were effectively amplified in another congeneric species, H. diversicolor diversicolor, indicating that these primers are useful for both abalone species. These microsatellite loci may be valuable for future aquaculture and population genetic studies aimed at

Ferritin from the Pacific abalone Haliotis discus hannai: Analysis of cDNA sequence, expression, and activity.

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Qiu, Reng; Kan, Yunchao; Li, Dandan

2016-02-01

Ferritin plays an important role in iron homeostasis due to its ability to bind and sequester large amounts of iron. In this study, the gene encoding a ferritin (HdhFer2) was cloned from Pacific abalone (Haliotis discus hannai). The full-length cDNA of HdhFer2 contains a 5'-UTR of 121 bp, an ORF of 516 bp, and a 3'-UTR of 252 bp with a polyadenylation signal sequence of AATAAA and a poly(A) tail. It also contains a 31 bp iron-responsive element (IRE) in the 5'-UTR position, which is conserved in many ferritins. HdhFer2 consists of 171 amino acid residues with a predicted molecular weight (MW) ∼19.8 kDa and a theoretical isoelectric point (PI) of 4.84. The deduced amino acid sequence of HdhFer2 contains two ferritin iron-binding region signatures (IBRSs). HdhFer2 mRNA was detected in a wide range of tissues and was dominantly expressed in the gill. Infection with the bacterial pathogen Vibrio anguillarum significantly upregulated HdhFer2 expression in a time-dependent manner. Recombinant HdhFer2 (rHdhFer2) purified from Escherichia coli was able to bind ferrous iron in a concentration-dependent manner. In summary, these results suggest that HdhFer2 is a crucial protein in the iron-withholding defense system, and plays an important role in the innate immune response of abalone. Copyright © 2016 Elsevier Ltd. All rights reserved.

Design of an optimum computer vision-based automatic abalone (Haliotis discus hannai) grading algorithm.

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Lee, Donggil; Lee, Kyounghoon; Kim, Seonghun; Yang, Yongsu

2015-04-01

An automatic abalone grading algorithm that estimates abalone weights on the basis of computer vision using 2D images is developed and tested. The algorithm overcomes the problems experienced by conventional abalone grading methods that utilize manual sorting and mechanical automatic grading. To design an optimal algorithm, a regression formula and R(2) value were investigated by performing a regression analysis for each of total length, body width, thickness, view area, and actual volume against abalone weights. The R(2) value between the actual volume and abalone weight was 0.999, showing a relatively high correlation. As a result, to easily estimate the actual volumes of abalones based on computer vision, the volumes were calculated under the assumption that abalone shapes are half-oblate ellipsoids, and a regression formula was derived to estimate the volumes of abalones through linear regression analysis between the calculated and actual volumes. The final automatic abalone grading algorithm is designed using the abalone volume estimation regression formula derived from test results, and the actual volumes and abalone weights regression formula. In the range of abalones weighting from 16.51 to 128.01 g, the results of evaluation of the performance of algorithm via cross-validation indicate root mean square and worst-case prediction errors of are 2.8 and ±8 g, respectively. © 2015 Institute of Food Technologists®

First insight into the heritable variation of the resistance to infection with the bacteria causing the withering syndrome disease in Haliotis rufescens abalone.

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Brokordt, Katherina; González, Roxana; Farías, William; Winkler, Federico E; Lohrmann, Karin B

2017-11-01

Withering syndrome disease has experienced worldwide spread in the last decade. This fatal disease for abalone is produced by a rickettsia-like organism (WS-RLO), the bacterium "Candidatus Xenohaliotis californiensis". To evaluate the potential of the red abalone (Haliotis rufescens) to improve its resistance to infection by WS-RLO, the additive genetic component in the variation of this trait was estimated. For this, the variation in infection intensity with WS-RLOs and WS-RLOv (phage-infected RLOs) was analyzed in 56 families of full-sibs maintained for three years in a host-parasite cohabitation aquaculture system. A WS-RLO prevalence of 65% was observed in the analysed population; and from the total WS-RLO inclusions 60% were hyperparasited with the phage (WS-RLOv). The decrease in the food ingestion rate was the sole negative effect associated with increasing WS-RLO intensity of infection, suggesting that the high level of WS-RLOv load may have diminished the symptoms of WS disease in the analyzed abalones. The estimated heritabilities were moderate to mid, but significant, varying from 0.21 to 0.23 and 0.36 for WS-RLO and WS-RLOv infections, respectively. This suggests that variation in resistance to infection with WS-RLO may respond to selection in the evaluated red abalone population. Estimated response to selection (G) for the level of infection by WS-RLO indicated that if the 10% of red abalone with the lowest infection level is selected as broodstock, a 90% reduction in the intensity of infection in the progeny can be expected, even with the lowest estimation of heritability (h 2 =0.21). This strong response would be also due to the large phenotypic variance of this trait. Strong positive correlations, both phenotypic and genotypic, were observed between infection intensities with WS-RLO and WS-RLOv, indicating that selection to increase resistance to one of the types of RLOs will affect resistance in the other in the same direction. This is the first

Concentration and retention of Toxoplasma gondii surrogates from seawater by red abalone (Haliotis rufescens)

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Schott, Kristen C; Krusor, Colin; Tinker, M. Tim; Moore, James G.; Conrad, Patricia A.; Shapiro, Karen

2016-01-01

Small marine snails and abalone have been identified as high- and low-risk prey items, respectively, for exposure of threatened southern sea otters to Toxoplasma gondii, a zoonotic parasite that can cause fatal encephalitis in animals and humans. While recent work has characterized snails as paratenic hosts for T. gondii, the ability of abalone to vector the parasite has not been evaluated. To further elucidate why abalone predation may be protective against T. gondii exposure, this study aimed to determine whether: (1) abalone are physiologically capable of acquiring T. gondii; and (2) abalone and snails differ in their ability to concentrate and retain the parasite. Abalone were exposed to T. gondii surrogate microspheres for 24 h, and fecal samples were examined for 2 weeks following exposure. Concentration of surrogates was 2–3 orders of magnitude greater in abalone feces than in the spiked seawater, and excretion of surrogates continued for 14 days post-exposure. These results indicate that, physiologically, abalone and snails can equally vector T. gondii as paratenic hosts. Reduced risk of T. gondii infection in abalone-specializing otters may therefore result from abalone's high nutritional value, which implies otters must consume fewer animals to meet their caloric needs.

Concentration and retention of Toxoplasma gondii surrogates from seawater by red abalone (Haliotis rufescens).

Science.gov (United States)

Schott, Kristen C; Krusor, Colin; Tinker, M Tim; Moore, James; Conrad, Patricia A; Shapiro, Karen

2016-11-01

Small marine snails and abalone have been identified as high- and low-risk prey items, respectively, for exposure of threatened southern sea otters to Toxoplasma gondii, a zoonotic parasite that can cause fatal encephalitis in animals and humans. While recent work has characterized snails as paratenic hosts for T. gondii, the ability of abalone to vector the parasite has not been evaluated. To further elucidate why abalone predation may be protective against T. gondii exposure, this study aimed to determine whether: (1) abalone are physiologically capable of acquiring T. gondii; and (2) abalone and snails differ in their ability to concentrate and retain the parasite. Abalone were exposed to T. gondii surrogate microspheres for 24 h, and fecal samples were examined for 2 weeks following exposure. Concentration of surrogates was 2-3 orders of magnitude greater in abalone feces than in the spiked seawater, and excretion of surrogates continued for 14 days post-exposure. These results indicate that, physiologically, abalone and snails can equally vector T. gondii as paratenic hosts. Reduced risk of T. gondii infection in abalone-specializing otters may therefore result from abalone's high nutritional value, which implies otters must consume fewer animals to meet their caloric needs.

Potential mechanisms of phthalate ester embryotoxicity in the abalone Haliotis diversicolor supertexta

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Zhou Jin [L-304, Life Sciences Division, Graduate School at Shenzhen, Tsinghua University, Shenzhen University Town, Xili, Shenzhen City 518055 (China); Cai Zhonghua, E-mail: caizh@sz.tsinghua.edu.cn [L-304, Life Sciences Division, Graduate School at Shenzhen, Tsinghua University, Shenzhen University Town, Xili, Shenzhen City 518055 (China); Key Laboratory of Aquatic-Ecology, Tianjin Agricultural University, Lishui Road 112, Tianjin 300384 (China); Xing Kezhi [Key Laboratory of Aquatic-Ecology, Tianjin Agricultural University, Lishui Road 112, Tianjin 300384 (China)

2011-05-15

The effects and associated toxicological mechanisms of five phthalate esters (PAEs) on abalone embryonic development were investigated by exposing the embryos to a range of PAEs concentrations (0.05, 0.2, 2 and 10 {mu}g/mL). The results showed that PAEs could significantly reduce embryo hatchability, increase developmental malformations, and suppress the metamorphosis of abalone larvae. The possible toxicological mechanisms of PAEs to abalone embryos included, affecting the Na{sup +}-K{sup +}-pump and Ca{sup 2+}-Mg{sup 2+}-pump activities, altering the peroxidase (POD) level and the malondialdehyde (MDA) production, damaging the extraembryonic membranes structure, as well as disrupting endocrine-related genes (gpx, cyp3a, and 17{beta}-hsd 12) expression properties. Taken together, this work showed that PAEs adversely affected the embryonic ontogeny of abalone. The abilities of PAEs affecting the osmoregulation, inducing oxidative stress, damaging embryo envelope structure, and causing physiological homeostasis disorder, are likely to be a part of the common mechanisms responsible for their embryonic toxicity. - Highlights: > PAEs affected abalone hatchability, morphogenesis and metamorphosis behavior. > The toxicity of the five PAEs to embryogenesis was ranked as DBP > DEP > DMP > DOP > DEHP. > The osmoregulation disorder and oxidative damage are the potential mechanisms. - Potential mechanisms of PAEs on abalone embryogenesis are osmoregulation disorder, oxidative damage and physiological dysfunction.

Potential mechanisms of phthalate ester embryotoxicity in the abalone Haliotis diversicolor supertexta

International Nuclear Information System (INIS)

Zhou Jin; Cai Zhonghua; Xing Kezhi

2011-01-01

The effects and associated toxicological mechanisms of five phthalate esters (PAEs) on abalone embryonic development were investigated by exposing the embryos to a range of PAEs concentrations (0.05, 0.2, 2 and 10 μg/mL). The results showed that PAEs could significantly reduce embryo hatchability, increase developmental malformations, and suppress the metamorphosis of abalone larvae. The possible toxicological mechanisms of PAEs to abalone embryos included, affecting the Na + -K + -pump and Ca 2+ -Mg 2+ -pump activities, altering the peroxidase (POD) level and the malondialdehyde (MDA) production, damaging the extraembryonic membranes structure, as well as disrupting endocrine-related genes (gpx, cyp3a, and 17β-hsd 12) expression properties. Taken together, this work showed that PAEs adversely affected the embryonic ontogeny of abalone. The abilities of PAEs affecting the osmoregulation, inducing oxidative stress, damaging embryo envelope structure, and causing physiological homeostasis disorder, are likely to be a part of the common mechanisms responsible for their embryonic toxicity. - Highlights: → PAEs affected abalone hatchability, morphogenesis and metamorphosis behavior. → The toxicity of the five PAEs to embryogenesis was ranked as DBP > DEP > DMP > DOP > DEHP. → The osmoregulation disorder and oxidative damage are the potential mechanisms. - Potential mechanisms of PAEs on abalone embryogenesis are osmoregulation disorder, oxidative damage and physiological dysfunction.

Two duplicated chicken-type lysozyme genes in disc abalone Haliotis discus discus: molecular aspects in relevance to structure, genomic organization, mRNA expression and bacteriolytic function.

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Umasuthan, Navaneethaiyer; Bathige, S D N K; Kasthuri, Saranya Revathy; Wan, Qiang; Whang, Ilson; Lee, Jehee

2013-08-01

Lysozymes are crucial antibacterial proteins that are associated with catalytic cleavage of peptidoglycan and subsequent bacteriolysis. The present study describes the identification of two lysozyme genes from disc abalone Haliotis discus discus and their characterization at sequence-, genomic-, transcriptional- and functional-levels. Two cDNAs and BAC clones bearing lysozyme genes were isolated from abalone transcriptome and BAC genomic libraries, respectively and sequences were determined. Corresponding deduced amino acid sequences harbored a chicken-type lysozyme (LysC) family profile and exhibited conserved characteristics of LysC family members including active residues (Glu and Asp) and GS(S/T)DYGIFQINS motif suggested that they are LysC counterparts in disc abalone and designated as abLysC1 and abLysC2. While abLysC1 represented the homolog recently reported in Ezo abalone [1], abLysC2 shared significant identity with LysC homologs. Unlike other vertebrate LysCs, coding sequence of abLysCs were distributed within five exons interrupted by four introns. Both abLysCs revealed a broader mRNA distribution with highest levels in mantle (abLysC1) and hepatopancreas (abLysC2) suggesting their likely main role in defense and digestion, respectively. Investigation of temporal transcriptional profiles post-LPS and -pathogen challenges revealed induced-responses of abLysCs in gills and hemocytes. The in vitro muramidase activity of purified recombinant (r) abLysCs proteins was evaluated, and findings indicated that they are active in acidic pH range (3.5-6.5) and over a broad temperature range (20-60 °C) and influenced by ionic strength. When the antibacterial spectra of (r)abLysCs were examined, they displayed differential activities against both Gram positive and Gram negative strains providing evidence for their involvement in bacteriolytic function in abalone physiology. Copyright © 2013 Elsevier Ltd. All rights reserved.

Construction of a stable GFP-tagged Vibrio harveyi strain for bacterial dynamics analysis of abalone infection.

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Travers, Marie-Agnès; Barbou, Annaïck; Le Goïc, Nelly; Huchette, Sylvain; Paillard, Christine; Koken, Marcel

2008-12-01

Vibrio harveyi is a bacterial marine pathogen that can cause fatal disease in a large range of vertebrates and invertebrates, including the commercially important marine gastropod, Haliotis tuberculata. Since 1997, strains of this bacterium have regularly been causing high mortalities in farmed and wild abalone populations. The way in which the pathogen enters into abalone and the disease transmission mechanisms are thus far unknown. Therefore, a pathogenic strain, ORM4, was green fluorescent protein-tagged and validated both for its growth characteristics and for its virulence as a genuine model for abalone disease. The strain allows V. harveyi quantification by flow cytometry in seawater and in abalone haemolymph as well as the in situ detection of the parasite inside abalone tissues.

Effects of waterborne Cu and Cd on anti-oxidative response, lipid peroxidation and heavy metals accumulation in abalone Haliotis discus hannai ino

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Lei, Yanju; Zhang, Wenbing; Xu, Wei; Zhang, Yanjiao; Zhou, Huihui; Mai, Kangsen

2015-06-01

The aim of this study was to compare the effects of waterborne copper (Cu) and cadmium (Cd) on survival, anti-oxidative response, lipid peroxidation and metal accumulation in abalone Haliotis discus hannai. Experimental animals (initial weight: 7.49 g ± 0.01 g) were exposed to graded concentrations of waterborne Cu (0.02, 0.04, 0.06, 0.08 mg L-1) or Cd (0.025, 0.05, 0.25, 0.5 mg L-1) for 28 days, respectively. Activities of the anti-oxidative enzymes (catalase, CAT; superoxide dismutase, SOD; glutathione peroxidases, GPx; glutathione S-transferase, GST), contents of the reduced glutathione (GSH) and malondiadehyde (MDA) in the hepatopancreas, and metal accumulation in hepatopancreas and muscles were analyzed after 0, 1, 3, 6, 10, 15, 21, 28 days of metal exposure, respectively. Results showed that 0.04 mg L-1, 0.06 mg L--1 and 0.08 mg L-1 Cu caused 100% death of abalone on the 21st, 10th and 6th day, respectively. However, no dead abalone was found during the 28-day waterborne Cd exposure at all experimental concentrations. Generally, activities of SOD and GST in hepatopancreas under all Cu concentrations followed a decrease trend as the exposure time prolonged. However, these activities were firstly increased and then decreased to the control level and increased again during Cd exposure. Activities of CAT in all Cu exposure treatments were higher than those in the control. These activities were firstly increased and then decreased to the control level and increased again during Cd exposure. Contents of MDA in hepatopancreas in all Cu treatments significantly increased first and then decreased to the control level. However, the MDA contents in hepatopancreas were not significantly changed during the 28-day Cd exposure. The metals accumulation in both hepatopancreas and muscles of abalone significantly increased with the increase of waterborne metals concentration and exposure time. These results indicated that H. discus hannai has a positive anti-oxidative defense

Analysis of microbiota on abalone (Haliotis discus hannai) in South Korea for improved product management.

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Lee, Min-Jung; Lee, Jin-Jae; Chung, Han Young; Choi, Sang Ho; Kim, Bong-Soo

2016-10-03

Abalone is a popular seafood in South Korea; however, because it contains various microorganisms, its ingestion can cause food poisoning. Therefore, analysis of the microbiota on abalone can improve understanding of outbreaks and causes of food poisoning and help to better manage seafood products. In this study, we collected a total of 40 abalones from four different regions in March and July, which are known as the maximum abalone production areas in Korea. The microbiota were analyzed using high-throughput sequencing, and bacterial loads on abalone were quantified by real-time PCR. Over 2700 species were detected in the samples, and Alpha- and Gammaproteobacteria were the predominant classes. The differences in microbiota among regions and at each sampling time were also investigated. Although Psychrobacter was the dominant genus detected on abalone in both March and July, the species compositions were different between the two sampling times. Five potential pathogens (Lactococcus garvieae, Yersinia kristensenii, Staphylococcus saprophyticus, Staphylococcus warneri, and Staphylococcus epidermidis) were detected among the abalone microbiota. In addition, we analyzed the influence of Vibrio parahaemolyticus infection on shifts in abalone microbiota during storage at different temperatures. Although the proportion of Vibrio increased over time in infected and non-infected abalone, the shifts of microbiota were more dynamic in infected abalone. These results can be used to better understand the potential of food poisoning caused by abalone consumption and manage abalone products according to the microbiota composition. Copyright © 2016 Elsevier B.V. All rights reserved.

Application of Novel Polymorphic Microsatellite Loci Identified in the Korean Pacific Abalone (Haliotis diversicolor supertexta (Haliotidae in the Genetic Characterization of Wild and Released Populations

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Seong Wan Hong

2012-08-01

Full Text Available The small abalone, Haliotis diversicolor supertexta, of the family Haliotidae, is one of the most important species of marine shellfish in eastern Asia. Over the past few decades, this species has drastically declined in Korea. Thus, hatchery-bred seeds have been released into natural coastal areas to compensate for the reduced fishery resources. However, information on the genetic background of the small abalone is scarce. In this study, 20 polymorphic microsatellite DNA markers were identified using next-generation sequencing techniques and used to compare allelic variation between wild and released abalone populations in Korea. Using high-throughput genomic sequencing, a total of 1516 (2.26%; average length of 385 bp reads containing simple sequence repeats were obtained from 86,011 raw reads. Among the 99 loci screened, 28 amplified successfully, and 20 were polymorphic. When comparing allelic variation between wild and released abalone populations, a total of 243 different alleles were observed, with 18.7 alleles per locus. High genetic diversity (mean heterozygosity = 0.81; mean allelic number = 15.5 was observed in both populations. A statistical analysis of the fixation index (F_ST and analysis of molecular variance (AMOVA indicated limited genetic differences between the two populations (F_ST = 0.002, p > 0.05. Although no significant reductions in the genetic diversity were found in the released population compared with the wild population (p > 0.05, the genetic diversity parameters revealed that the seeds released for stock abundance had a different genetic composition. These differences are likely a result of hatchery selection and inbreeding. Additionally, all the primer pair sets were effectively amplified in another congeneric species, H. diversicolor diversicolor, indicating that these primers are useful for both abalone species. These microsatellite loci

The Effect of Pleistocene Climate Fluctuations on Distribution of European Abalone (Haliotis tuberculata), Revealed by Combined Mitochondrial and Nuclear Marker Analyses.

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Roussel, Valérie; Van Wormhoudt, Alain

2017-04-01

The genetic differentiation among the populations of the European abalone Haliotis tuberculata was investigated using different markers to better understand the evolutionary history and exchanges between populations. Three markers were used: mitochondrial cytochrome oxidase I (COI), the sperm lysin nuclear gene, and eight nuclear microsatellites. These markers present different characteristics concerning mutation rate and inheritance, which provided complementary information about abalone history and gene diversity. Genetic diversity and relationships among subspecies were calculated from a sample of approximately 500 individuals, collected from 17 different locations in the north-eastern Atlantic Ocean, Macaronesia, and Mediterranean Sea. COI marker was used to explore the phylogeny of the species with a network analysis and two phylogenetic methods. The analysis revealed 18 major haplotypes grouped into two distinct clades with a pairwise sequence divergence up to 3.5 %. These clades do not correspond to subspecies but revealed many contacts along Atlantic coast during the Pleistocene interglaciations. The sperm lysin gene analysis separated two different subtaxa: one associated to Macaronesian islands, and the other to all other populations. Moreover, a small population of the northern subtaxon was isolated in the Adriatic Sea-probably before the separation of the two lineages-and evolved independently. Microsatellites were analyzed by different genetics methods, including the Bayesian clustering method and migration patterns analysis. It revealed genetically distinct microsatellite patterns among populations from Mediterranean Sea, Brittany and Normandy, Morocco, and Canary and Balearic islands. Gene flow is asymmetric among the regions; the Azores and the Canary Islands are particularly isolated and have low effective population sizes. Our results support the hypothesis that climate changes since the Pleistocene glaciations have played a major role in the

Nacre in Abalone Shell: Organic and Inorganic Components and their effects to the Formation and Mechanical Properties

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Lopez, Maria Isabel

Abalone nacre is a natural composite that exhibits exceptional mechanical properties due to its organization that extends to various levels of hierarchy. Most of the toughness has been attributed by nacre's third level of hierarchy which entitles a brick and mortar structure consisting of the CaCO3 tiles and organic interlayers. However, there are other important components that are vital to the structure and strength of red abalone nacre. The process of formation of red abalone (Haliotis rufescens) nacre following periods of growth interruption, taking into consideration important environmental factors (access to food and temperature) and to employ high-magnification characterization techniques (scanning electron microscopy and transmission electron microscopy) to better understand how the soft tissue (e.g. epithelium and organic membrane) influences the mechanism of growth. The structure-property relationship of red abalone (Haliotis rufescens) nacre, focusing in the individual constituents (isolated mineral and isolated organic component) and comparing that to the integrated structure. Mechanical tests such as, tensile tests, microscratch, and nanoindentation is performed on the isolated organic constituent and the isolated mineral of red abalone shell. Specimens are characterized by SEM to verify the toughening and deformation mechanisms. Results obtained from the isolated mineral validate the importance of the organic constituent as the mechanical properties decline greatly as the organic component is removed. This approach forms a general picture of the mechanical response of the organic interlayers and growth bands and their effect on the toughness of the abalone nacre. These results are significant to understand the important characteristics of abalone nacre, such as the structure and mechanical properties, and an attempt to aid in improving the latest attempts to produce novel nacre-inspired materials.

Effect of antiaggregants on the in vitro viability, cell count and stability of abalone (Haliotis iris) haemocytes.

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Grandiosa, Roffi; Bouwman, Mai-Louise; Young, Tim; Mérien, Fabrice; Alfaro, Andrea C

2018-07-01

The ability to successfully prepare and preserve haemocyte cells for microscopy and flow cytometry is critical for the investigation of animal immune systems. In this study, we observed the total cell count, in vitro viability and stability of New Zealand black-footed abalone (Haliotis iris) haemocytes with different antiaggregants and handling protocols. Haemocyte stability was evaluated by direct observation of haemocytes under the microscope and calculating the aggregation index. Haemocyte counts and viability were measured via flow cytometry and tested for the effect of different antiaggregants (Alsever's solution at three concentrations, and specialised blood collection tubes containing lithium heparin and K 2 EDTA) at different temperatures and storage times. Results showed that Alsever's solution is an effective antiaggregant at haemolymph:antiaggregant dilution ratios of 1:1, 1:2 and 1:3. Lithium heparin was ineffective as an antiaggregant, whereas K 2 EDTA was similarly as effective as Alsever's solution. The influence of different mixing techniques (vortex, pipetting and flipping) were subsequently tested using the K 2 EDTA Microtainer ® tubes, revealing that proper mixing should be performed immediately. High cell viability can be achieved by mixing samples by either 10 s of vortexing (1000 rpm), 10 times pipetting or 20 times flipping. The in vitro storage of abalone haemocytes in AS and K 2 EDTA as antiaggregants at ambient room temperature was highly effective for up to 24 h (75-85% viability; 0.05-0.15 aggregation index) and is recommended for haemocyte studies in H. iris. Utilization of K 2 EDTA Microtainer ® tubes were advantageous since they are more cost effective compared to Alsever's solution, and samples can be prepared more efficiently. Copyright © 2018. Published by Elsevier Ltd.

Effects of a range-expanding sea urchin on behaviour of commercially fished abalone.

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Strain, Elisabeth M A; Johnson, Craig R; Thomson, Russell J

2013-01-01

Global climate change has resulted in a southerly range expansion of the habitat modifying sea urchin Centrostephanus rodgersii to the east coast of Tasmania, Australia. Various studies have suggested that this urchin outcompetes black-lipped abalone (Haliotis rubra) for resources, but experiments elucidating the mechanisms are lacking. We outline a new framework involving experimental manipulations and Markov chain and Pareto modelling to examine the effects of interspecific competition between urchins and abalone and the effect of intraspecific competition in abalone, assessed as effects on behaviour. Manipulations of abalone densities had no detectable effect on urchin behavioural transitions, movement patterns or resightability through time. In contrast, additions of urchins resulted in abalone shifting microhabitats from exposed to sheltered positions, an increase in the proportion of mobile abalone, and declines in abalone resightability through time relative to controls without the urchins. Our results support the hypothesis of asymmetrical competitive interactions between urchins and abalone. The introduction of urchins to intact algal beds causes abalone to flee and seek shelter in cryptic microhabitat which will negatively impact both their accessibility to such microhabitats, and productivity of the abalone fishery, and will potentially affect their growth and survival, while the presence of the abalone has no detectable effect on the urchin. Our approach involving field-based experiments and modelling could be used to test the effects of other invasive species on native species behaviour.

The South African commercial abalone Haliotis midae fishery began ...

African Journals Online (AJOL)

spamer

and 20 m deep, and virtually no abalone occur at ... factories were granted processing rights to a fixed percentage of an overall .... behaviour and temporal change in individual and aggre- ... series, is to gain further information through carefully.

Metabolic responses of Haliotis diversicolor to Vibrio parahaemolyticus infection.

Science.gov (United States)

Lu, Jie; Shi, Yanyan; Cai, Shuhui; Feng, Jianghua

2017-01-01

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. Copyright © 2016 Elsevier Ltd. All rights reserved.

Variable intertidal temperature explains why disease endangers black abalone

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Ben-Horin, Tal; Lenihan, Hunter S.; Lafferty, Kevin D.

2013-01-01

Epidemiological theory suggests that pathogens will not cause host extinctions because agents of disease should fade out when the host population is driven below a threshold density. Nevertheless, infectious diseases have threatened species with extinction on local scales by maintaining high incidence and the ability to spread efficiently even as host populations decline. Intertidal black abalone (Haliotis cracherodii), but not other abalone species, went extinct locally throughout much of southern California following the emergence of a Rickettsiales-like pathogen in the mid-1980s. The rickettsial disease, a condition known as withering syndrome (WS), and associated mortality occur at elevated water temperatures. We measured abalone body temperatures in the field and experimentally manipulated intertidal environmental conditions in the laboratory, testing the influence of mean temperature and daily temperature variability on key epizootiological processes of WS. Daily temperature variability increased the susceptibility of black abalone to infection, but disease expression occurred only at warm water temperatures and was independent of temperature variability. These results imply that high thermal variation of the marine intertidal zone allows the pathogen to readily infect black abalone, but infected individuals remain asymptomatic until water temperatures periodically exceed thresholds modulating WS. Mass mortalities can therefore occur before pathogen transmission is limited by density-dependent factors.

Heterosis and combining ability: a diallel cross of three geographically isolated populations of Pacific abalone Haliotis discus hannai Ino

Science.gov (United States)

Deng, Yuewen; Liu, Xiao; Zhang, Guofan; Wu, Fucun

2010-11-01

We conducted a complete diallel cross among three geographically isolated populations of Pacific abalone Haliotis discus hannai Ino to determine the heterosis and the combining ability of growth traits at the spat stage. The three populations were collected from Qingdao (Q) and Dalian (D) in China, and Miyagi (M) in Japan. We measured the shell length, shell width, and total weight. The magnitude of the general combining ability (GCA) variance was more pronounced than the specific combining ability (SCA) variance, which is evidenced by both the ratio of the genetic component in total variation and the GCA/SCA values. The component variances of GCA and SCA were significant for all three traits ( P<0.05), indicating the importance of additive and non-additive genetic effects in determining the expression of these traits. The reciprocal maternal effects (RE) were also significant for these traits ( P<0.05). Our results suggest that population D was the best general combiner in breeding programs to improve growth traits. The DM cross had the highest heterosis values for all three traits.

Effects of a range-expanding sea urchin on behaviour of commercially fished abalone.

Directory of Open Access Journals (Sweden)

Elisabeth M A Strain

Full Text Available Global climate change has resulted in a southerly range expansion of the habitat modifying sea urchin Centrostephanus rodgersii to the east coast of Tasmania, Australia. Various studies have suggested that this urchin outcompetes black-lipped abalone (Haliotis rubra for resources, but experiments elucidating the mechanisms are lacking.We outline a new framework involving experimental manipulations and Markov chain and Pareto modelling to examine the effects of interspecific competition between urchins and abalone and the effect of intraspecific competition in abalone, assessed as effects on behaviour. Manipulations of abalone densities had no detectable effect on urchin behavioural transitions, movement patterns or resightability through time. In contrast, additions of urchins resulted in abalone shifting microhabitats from exposed to sheltered positions, an increase in the proportion of mobile abalone, and declines in abalone resightability through time relative to controls without the urchins. Our results support the hypothesis of asymmetrical competitive interactions between urchins and abalone.The introduction of urchins to intact algal beds causes abalone to flee and seek shelter in cryptic microhabitat which will negatively impact both their accessibility to such microhabitats, and productivity of the abalone fishery, and will potentially affect their growth and survival, while the presence of the abalone has no detectable effect on the urchin. Our approach involving field-based experiments and modelling could be used to test the effects of other invasive species on native species behaviour.

Exploiting genomic data to identify proteins involved in abalone reproduction.

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Mendoza-Porras, Omar; Botwright, Natasha A; McWilliam, Sean M; Cook, Mathew T; Harris, James O; Wijffels, Gene; Colgrave, Michelle L

2014-08-28

Aside from their critical role in reproduction, abalone gonads serve as an indicator of sexual maturity and energy balance, two key considerations for effective abalone culture. Temperate abalone farmers face issues with tank restocking with highly marketable abalone owing to inefficient spawning induction methods. The identification of key proteins in sexually mature abalone will serve as the foundation for a greater understanding of reproductive biology. Addressing this knowledge gap is the first step towards improving abalone aquaculture methods. Proteomic profiling of female and male gonads of greenlip abalone, Haliotis laevigata, was undertaken using liquid chromatography-mass spectrometry. Owing to the incomplete nature of abalone protein databases, in addition to searching against two publicly available databases, a custom database comprising genomic data was used. Overall, 162 and 110 proteins were identified in females and males respectively with 40 proteins common to both sexes. For proteins involved in sexual maturation, sperm and egg structure, motility, acrosomal reaction and fertilization, 23 were identified only in females, 18 only in males and 6 were common. Gene ontology analysis revealed clear differences between the female and male protein profiles reflecting a higher rate of protein synthesis in the ovary and higher metabolic activity in the testis. A comprehensive mass spectrometry-based analysis was performed to profile the abalone gonad proteome providing the foundation for future studies of reproduction in abalone. Key proteins involved in both reproduction and energy balance were identified. Genomic resources were utilised to build a database of molluscan proteins yielding >60% more protein identifications than in a standard workflow employing public protein databases. Copyright © 2014 Elsevier B.V. All rights reserved.

Beta-1,3-1,6-glucan modulate the non-specific immune response to enhance the survival in the Vibrio alginolyticus infection of Taiwan abalone (Haliotis diversicolor supertexta).

Science.gov (United States)

Wu, Yu-Sheng; Tseng, Tzu-Yu; Nan, Fan-Hua

2016-07-01

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 (O2(-)), 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), O2(-), 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. Copyright © 2016 Elsevier Ltd. All rights reserved.

Types and distribution of mucous cells of the abalone Haliotis ...

African Journals Online (AJOL)

user

2012-05-08

May 8, 2012 ... Key words: Haliotis diversicolor; mucous cells, types, distribution. .... Figure 2. The shape of the mucous cells. O (oval or circle-like); c (cup- like); s ... (J) mucous cells at base of gill filaments, small cells, type II and type III; (K) a ...

iTRAQ-Based Identification of Proteins Related to Muscle Growth in the Pacific Abalone, Haliotis discus hannai

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Jianfang Huang

2017-10-01

Full Text Available The abalone Haliotis discus hannai is an important aquaculture species that is grown for human consumption. However, little is known of the genetic mechanisms governing muscle growth in this species, particularly with respect to proteomics. The isobaric tag for relative and absolute quantitation (iTRAQ method allows for sensitive and accurate protein quantification. Our study was the first to use iTRAQ-based quantitative proteomics to investigate muscle growth regulation in H. discus hannai. Among the 1904 proteins identified from six samples, 125 proteins were differentially expressed in large specimens of H. discus hannai as compared to small specimens. In the large specimens, 47 proteins were upregulated and 78 were downregulated. Many of the significant Kyoto Encyclopedia of Genes and Genomes (KEGG pathways, including these differentially expressed proteins, were closely related to muscle growth, including apoptosis, thyroid hormone signaling, regulation of the actin cytoskeleton, and viral myocarditis (p < 0.05. Our quantitative real-time polymerase chain reaction (qRT-PCR analyses suggested that the alterations in expression levels observed in the differentially expressed proteins were consistent with the alterations observed in the encoding mRNAs, indicating the repeatability of our proteomic approach. Our findings contribute to the knowledge of the molecular mechanisms of muscle growth in H. discus hannai.

Protective Efficacy of a Pseudoalteromonas Strain in European Abalone, Haliotis tuberculata, Infected with Vibrio harveyi ORM4.

Science.gov (United States)

Offret, Clément; Rochard, Vincent; Laguerre, Hélène; Mounier, Jérôme; Huchette, Sylvain; Brillet, Benjamin; Le Chevalier, Patrick; Fleury, Yannick

2018-02-06

The hemolymph of healthy marine invertebrates is known to harbor antibiotic-producing bacteria belonging to the genus Pseudoalteromonas. Such strains are potential probiotics to control infectious diseases in aquaculture. In the present study, we screened a collection of Pseudoalteromonas strains isolated from the hemolymph of oyster and mussel for antimicrobial activity against Vibrio harveyi, a pathogenic species responsible for high mortality in abalone. Subsequently, the protective efficacy of the most active strain named hCg-6 was investigated in abalone culture faced with a Vibrio harveyi ORM4 infection. First, we have controlled the Pseudoalteromonas hCg-6 safety for abalone health. To that end, animals were immersed for 4 h in Pseudoalteromonas hCg-6 suspensions in seawater. The abalone viability was monitored and Pseudoalteromonas hCg-6 was tracked by quantitative-PCR in abalone hemolymph. After immersion, no abalone death occurred while the strain hCg-6 was significantly detected in hemolymph. Therefore, the strain hCg-6 was considered safe for abalone and evaluated for its ability to protect abalone against V. harveyi (injection of 1 × 10 3 Vibrio per animal). A 4-h long immersion of abalone in a seawater suspension of Pseudoalteromonas hCg-6 (1 × 10 6  CFU mL -1 ) prior to infection with Vibrio harveyi significantly improved the abalone viability. Indeed, 15 days post infection, the hCg-6 treatment used increased the abalone survival rate from 16% in untreated animals to 40% in treated abalone. We hypothesized that Pseudoalteromonas hCg-6 antibacterial activity increased the hemomicrobiota shielding effect. In conclusion, Pseudoalteromonas hCg-6 is a promising anti-Vibrio strain for abalone culture.

Types and distribution of mucous cells of the abalone Haliotis ...

African Journals Online (AJOL)

The types and distribution of mucous cells of Haliotis diversicolorwere observed and analyzed using the alcian blue and periodic acid schiffs (AB-PAS) reaction and histological procedures. According to the color of the mucous cells, they were divided into four types: Type I, pure red; type II, pure blue; type III, purple reddish; ...

Evaluating potential conservation conflicts between two listed species: sea otters and black abalone.

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Raimondi, Peter; Jurgens, Laura J; Tinker, M Tim

2015-11-01

Population consequences of endangered species interacting as predators and prey have been considered theoretically and legally, but rarely investigated in the field. We examined relationships between spatially variable populations of a predator, the California sea otter, Enhydra lutris nereis, and a prey species, the black abalone, Haliotis cracherodii. Both species are federally listed under the Endangered Species Act and co-occur along the coast of California. We compared the local abundance and habitat distribution of black abalone at 12 sites with varying densities of sea otters. All of the populations of abalone we examined were in the geographic area currently unaffected by withering disease, which has decimated populations south of the study area. Surprisingly, our findings indicate that sea otter density is positively associated with increased black abalone density. The presence of sea otters also correlated with a shift in black abalone to habitat conferring greater refuge, which could decrease illegal human harvest. These results highlight the need for a multi-species approach to conservation management of the two species, and demonstrate the importance of using field-collected data rather than simple trophic assumptions to understand relationships between jointly vulnerable predator and prey populations.

Contributions to the knowledge of the Biology of the Arabian Abalone Haliotis mariae Wood, 1828

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J. Stirn

1996-01-01

Full Text Available The Arabian abalone occur in the Arabian Sea’s rocky coastal zone in association with conspicuous macrolgal communities in which it represents the dominant herbivorous component. Despite such ecological importance and although the commercial exploitation of abalone presents a considerable contribution to Omani fisheries, almost nothing is known about the biology of this species. This report presents results of research carried out in the field and with laboratory cultures, and draws general conclusions related also to the fisheries management of these possibly overexploited abalone populations, Cobort observations in the field and measured increments of cultured specimens showed a growth rate significantly higher than in other abalone species, i.e. greater than 3 mm shell-increment per month. The very early sexual maturity demonstrated by captivity spawnings of approximately one year old animals is also quite unusual. The ejected eggs formed mucous mono layers attached to the substratum whereas other abalone species produce pelagic eggs. Jvenile coborts in nature and the periodic spawning of cultured animals indicate the major spawning in spring and postmonsoon one in autumn. The models previously applied in fisheries management of abalone in Oman assumed only one spawning per year, the first being at age 2+, and a slower growth-rate. These models should be reconsidered using the new data, which may partially explain why abalone are less overexploited than one would expect looking at heavy harvesting. In view of a projected commercial abalone cultivation our laboratory rearing experiments showed that both natural and/or artificial food may be used, provided this contains-apart from standard ingredients, the seaweed-borne components (probably phycobillins required for a normal parasite , resistant shell formation. With regard to artificial reproduction,  our preliminary trials showed that spawning , fertilization ,and initial larval rearing

Marine environmental impact assessment of abalone, Haliotis discus hannai, cage farm in Wan-do, Republic of Korea

Science.gov (United States)

Oh, Hyun-Taik; Jung, Rae-Hong; Cho, Yoon-Sik; Hwang, Dong-Woon; Yi, Yong-Min

2015-12-01

To assess the marine environmental impacts of abalone, Haliotis discus hannai, cage farms in Wan-do, we monitored the benthic environment on top of the sediment underneath cage farm stations and reference stations. We applied two methods for this assessment. One was the A- and B-investigation of the MOM system (Modeling-On fish farm-Monitoring) developed in Norway. The other was a general environmental monitoring method which is widely used. In this study, we found benthic animals in all samples that belonged to condition 1 which were based on group 1(presence of macrofauna) of the B-investigation method. The values of redox potential (group 2-pH, redox potential) in all samples were above +65 mV belonging to condition 1. Based on sensory results (group 3-gas, color, odor, thickness of deposits), five out of seven experiment samples showed condition 1 while stations 2 and 7 showed condition 2, which have been cultured for 10 years in semi-closed waters. As group 2 takes precedence over group 3, the level of the conditions for B-investigation results consequently showed condition 1 in all stations. We found that pollutants and trace metals in the sediment underneath cage farms were lower than the pollution standard. This led us to conclude that the environmental impacts of the cage farms in this study were not significant.

Nitric oxide is not a negative regulator of metamorphic induction in the abalone Haliotis asinina

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Nobuo eUeda

2014-07-01

Full Text Available Nitric oxide (NO is a second messenger molecule synthesized by the enzyme nitric oxide synthase (NOS that requires the molecular chaperone heat shock protein 90 (HSP90 for normal enzymatic activity. Past studies have revealed that both NO and HSP90 act as negative regulators (repressors of metamorphosis in a diverse range of marine invertebrates, including several molluscan species. Here, we test the role of NO in the metamorphic induction of a vetigastropod mollusc, the tropical abalone Haliotis asinina. Specifically, we 1 test the effects of NO-manipulating pharmacological agents, 2 measure the temporal expression of NOS and HSP90 genes through metamorphosis, and 3 assess the spatial expression of NOS and HSP90 in larvae. We find that inhibition of NOS reduces rates of metamorphosis, indicating that NO facilitates, rather than represses, induction of metamorphosis in H. asinina. The marked increase in NOS expression in putative sensory cells localized to the anterior foot of competent larvae is consistent with NO as an inductive molecule for metamorphosis. In contrast to NOS, HSP90 transcript abundance decreases at competence and there is no evidence of NOS and HSP90 transcript co-localization. This study provides the first evidence of NO as an inductive facilitator of molluscan metamorphosis. Our experimental data suggest that NO modulates signals derived from live inductive substrates via the larval foot to regulate metamorphosis. Inter-specific comparisons of spatial NOS expression in molluscs suggest that the localized pattern of NOS or its protein product is related to the regulatory action of NO in metamorphosis.

Trading on extinction: An open-access deterrence model for the South African abalone fishery

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Douglas J. Crookes

2016-03-01

Full Text Available South African rhinoceros (e.g.Diceros bicornis and abalone (Haliotis midae have in common that they both are harvested under open-access conditions, are high-value commodities and are traded illegally. The difference is that a legal market for abalone already exists. An open-access deterrence model was developed for South African abalone, using Table Mountain National Park as a case study. It was found that illegal poaching spiked following the closure of the recreational fishery. The resource custodian's objective is to maximise returns from confiscations. This study showed that a legal trade results in a trading on extinction resource trap, with a race for profits, an increase in the probability of detection after a poaching event and the depletion of populations. In contrast with HS Gordon's seminal article (J Polit Econ 1954;62:124-142, profit maximisation does not automatically improve the sustainability of the resource. Under certain conditions (e.g. a legal trade with costly enforcement, profit maximisation may actually deplete abalone populations. The article also has implications for rhino populations, as a legal trade is currently proposed.

Reduced disease in black abalone following mass mortality: Phage therapy and natural selection

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VanBlaricom, Glenn R.

2014-01-01

Black abalone, Haliotis cracherodii, populations along the NE Pacific ocean have declined due to the rickettsial disease withering syndrome (WS). Natural recovery on San Nicolas Island (SNI) of Southern California suggested the development of resistance in island populations. Experimental challenges in one treatment demonstrated that progeny of disease-selected black abalone from SNI survived better than did those from naïve black abalone from Carmel Point in mainland coastal central California. Unexpectedly, the presence of a newly observed bacteriophage infecting the WS rickettsia (WS-RLO) had strong effects on the survival of infected abalone. Specifically, presence of phage-infected RLO (RLOv) reduced the host response to infection, RLO infection loads, and associated mortality. These data suggest that the black abalone: WS-RLO relationship is evolving through dual host mechanisms of resistance to RLO infection in the digestive gland via tolerance to infection in the primary target tissue (the post-esophagus) coupled with reduced pathogenicity of the WS-RLO by phage infection, which effectively reduces the infection load in the primary target tissue by half. Sea surface temperature patterns off southern California, associated with a recent hiatus in global-scale ocean warming, do not appear to be a sufficient explanation for survival patterns in SNI black abalone. These data highlight the potential for natural recovery of abalone populations over time and that further understanding of mechanisms governing host–parasite relationships will better enable us to manage declining populations.

Reduced disease in black abalone following mass mortality: Phage therapy and natural selection

Directory of Open Access Journals (Sweden)

Carolyn S Friedman

2014-03-01

Full Text Available Black abalone, Haliotis cracherodii, populations along the NE Pacific ocean have declined due to the rickettsial disease withering syndrome (WS. Natural recovery on San Nicolas Island (SNI off Southern California suggested the development of resistance in island populations. Experimental challenges in one treatment demonstrated that progeny of disease-selected black abalone from SNI survived better than did those from naïve black abalone from Carmel Point (CP in mainland coastal central California. Unexpectedly, the presence of a newly observed bacteriophage infecting the WS rickettsia (WS-RLO had strong effects on the survival of infected abalone. Specifically, presence of phage-infected RLO (RLOv reduced the host response to infection, RLO infection loads, and associated mortality. These data suggest that the black abalone: WS-RLO relationship is evolving through dual host mechanisms of resistance to RLO infection in the digestive gland via tolerance to infection in the primary target tissue (the post-esophagus coupled with reduced pathogenicity of the WS-RLO by phage infection, which effectively reduces the infection load in the primary target tissue by half. Sea surface temperature patterns off southern California, associated with a recent hiatus in global-scale ocean warming, do not appear to be a sufficient explanation for survival patterns in SNI black abalone. These data highlight the potential for natural recovery of abalone populations over time and that further understanding of mechanisms governing host-parasite relationships will better enable us to manage declining populations.

Reduced disease in black abalone following mass mortality: phage therapy and natural selection.

Science.gov (United States)

Friedman, Carolyn S; Wight, Nathan; Crosson, Lisa M; Vanblaricom, Glenn R; Lafferty, Kevin D

2014-01-01

Black abalone, Haliotis cracherodii, populations along the NE Pacific ocean have declined due to the rickettsial disease withering syndrome (WS). Natural recovery on San Nicolas Island (SNI) of Southern California suggested the development of resistance in island populations. Experimental challenges in one treatment demonstrated that progeny of disease-selected black abalone from SNI survived better than did those from naïve black abalone from Carmel Point in mainland coastal central California. Unexpectedly, the presence of a newly observed bacteriophage infecting the WS rickettsia (WS-RLO) had strong effects on the survival of infected abalone. Specifically, presence of phage-infected RLO (RLOv) reduced the host response to infection, RLO infection loads, and associated mortality. These data suggest that the black abalone: WS-RLO relationship is evolving through dual host mechanisms of resistance to RLO infection in the digestive gland via tolerance to infection in the primary target tissue (the post-esophagus) coupled with reduced pathogenicity of the WS-RLO by phage infection, which effectively reduces the infection load in the primary target tissue by half. Sea surface temperature patterns off southern California, associated with a recent hiatus in global-scale ocean warming, do not appear to be a sufficient explanation for survival patterns in SNI black abalone. These data highlight the potential for natural recovery of abalone populations over time and that further understanding of mechanisms governing host-parasite relationships will better enable us to manage declining populations.

Evaluation of reference genes for RT-qPCR study in abalone Haliotis discus hannai during heavy metal overload stress

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Sang Yoon Lee

2016-06-01

Full Text Available Abstract Background The evaluation of suitable reference genes as normalization controls is a prerequisite requirement for launching quantitative reverse transcription-PCR (RT-qPCR-based expression study. In order to select the stable reference genes in abalone Haliotis discus hannai tissues (gill and hepatopancreas under heavy metal exposure conditions (Cu, Zn, and Cd, 12 potential candidate housekeeping genes were subjected to expression stability based on the comprehensive ranking while integrating four different statistical algorithms (geNorm, NormFinder, BestKeeper, and ΔCT method. Results Expression stability in the gill subset was determined as RPL7 > RPL8 > ACTB > RPL3 > PPIB > RPL7A > EF1A > RPL4 > GAPDH > RPL5 > UBE2 > B-TU. On the other hand, the ranking in the subset for hepatopancreas was RPL7 > RPL3 > RPL8 > ACTB > RPL4 > EF1A > RPL5 > RPL7A > B-TU > UBE2 > PPIB > GAPDH. The pairwise variation assessed by the geNorm program indicates that two reference genes could be sufficient for accurate normalization in both gill and hepatopancreas subsets. Overall, both gill and hepatopancreas subsets recommended ribosomal protein genes (particularly RPL7 as stable references, whereas traditional housekeepers such as β-tubulin (B-TU and glyceraldehyde-3-phosphate dehydrogenase (GAPDH genes were ranked as unstable genes. The validation of reference gene selection was confirmed with the quantitative assay of MT transcripts. Conclusions The present analysis showed the importance of validating reference genes with multiple algorithmic approaches to select genes that are truly stable. Our results indicate that expression stability of a given reference gene could not always have consensus across tissue types. The data from this study could be a good guide for the future design of RT-qPCR studies with respect to metal regulation/detoxification and other related

Attenuation of UV-B exposure-induced inflammation by abalone hypobranchial gland and gill extracts.

Science.gov (United States)

Kuanpradit, Chitraporn; Jaisin, Yamaratee; Jungudomjaroen, Sumon; Akter Mitu, Shahida; Puttikamonkul, Srisombat; Sobhon, Prasert; Cummins, Scott F

2017-05-01

Exposure to solar ultraviolet B (UV-B) is a known causative factor for many skin complications such as wrinkles, black spots, shedding and inflammation. Within the wavelengths 280‑320 nm, UV-B can penetrate to the epidermal level. This investigation aimed to test whether extracts from the tropical abalone [Haliotis asinina (H. asinina)] mucus-secreting tissues, the hypobranchial gland (HBG) and gills, were able to attenuate the inflammatory process, using the human keratinocyte HaCaT cell line. Cytotoxicity of abalone tissue extracts was determined using an AlamarBlue viability assay. Results showed that HaCaT cells could survive when incubated in crude HBG and gill extracts at concentrations between abalone extract from both the HBG and gill (0, 0.1, 2.5, 5 µg/ml). A significant increase in cell viability was observed (P2.5 µg/ml extract showed a significant decrease in intensity for COX‑2, phospho‑p38 and phospho‑SPK/JNK. The present study demonstrated that abalone extracts from the HGB and gill can attenuate inflammatory proteins triggered by UV-B. Hence, the contents of abalone extract, including cellmetabolites and peptides, may provide new agents for skin anti‑inflammation, preventing damage due to UV-B.

Transcriptional responses of metallothionein gene to different stress factors in Pacific abalone (Haliotis discus hannai).

Science.gov (United States)

Lee, Sang Yoon; Nam, Yoon Kwon

2016-11-01

A novel metallothionein (MT) gene from the Pacific abalone H. discus hannai was characterized and its mRNA expression patterns (tissue distribution, developmental expression and differential expression in responsive to various in vivo stimulatory treatments) were examined. Abalone MT shares conserved structural features with previously known gastropod orthologs at both genomic (i.e., tripartite organization) and amino acid (conserved Cys motifs) levels. The 5'-flanking regulatory region of abalone MT gene displayed various transcription factor binding motifs particularly including ones related with metal regulation and stress/immune responses. Tissue distribution and basal expression patterns of MT mRNAs indicated a potential association between ovarian MT expression and sexual maturation. Developmental expression pattern suggested the maternal contribution of MT mRNAs to embryonic and early larval developments. Abalone MT mRNAs could be significantly induced by various heavy metals in different tissues (gill, hepatopancreas, muscle and hemocyte) in a tissue- and/or metal-dependent fashion. In addition, the abalone MT gene was highly modulated in responsive to other non-metal, stimulatory treatments such as immune challenge (LPS, polyI:C and bacterial injections), hypoxia (decrease from normoxia 8 ppm-2 ppm), thermal elevation (increase from 20 °C to 30 °C), and xenobiotic exposure (250 ppb of 17α-ethynylestradiol and 0.25 ppb of 2,3,7,8-tetrachlorodibenzodioxin) where differential expression patterns were toward either up- or down-regulation depending on types of stimulations and tissues examined. Taken together, our results highlight that MT is a multifunctional effector playing in wide criteria of cellular pathways especially associated with development and stress responses in this abalone species. Copyright © 2016 Elsevier Ltd. All rights reserved.

Antibiotic resistance monitoring in Vibrio spp. isolated from rearing environment and intestines of abalone Haliotis diversicolor.

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Wang, R X; Wang, J Y; Sun, Y C; B L Yang; A L Wang

2015-12-30

546 Vibrio isolates from rearing seawater (292 strains) and intestines of abalone (254 strains) were tested to ten antibiotics using Kirby-Bauer diffusion method. Resistant rates of abalone-derived Vibrio isolates to chloramphenicol (C), enrofloxacin (ENX) and norfloxacin (NOR) were 40%) to kanamycin (KNA), furazolidone (F), tetracycline (TE), gentamicin (GM) and rifampin (RA). 332 isolates from seawater (n=258) and abalone (n=74) were resistant to more than three antibiotics. Peaked resistant rates of seawater-derived isolates to multiple antibiotics were overlapped in May and August. Statistical analysis showed that pH had an important effect on resistant rates of abalone-derived Vibrio isolates to RA, NOR, and ENX. Salinity and dissolved oxygen were negatively correlated with resistant rates of seawater-derived Vibrio isolates to KNA, RA, and PG. Copyright © 2015 Elsevier Ltd. All rights reserved.

Comparison of three inert markers in measuring apparent nutrient digestibility of juvenile abalone under different culture condition and temperature regimes

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Nur, K. U.; Adams, L.; Stone, D.; Savva, N.; Adams, M.

2018-03-01

A comparative research using three inert markers, chromic oxide, yttrium and ytterbium to measure the apparent nutrient digestibility of experimental feed in juvenile Hybrid abalone (Haliotis rubra X H. laevigata) and Greenlip abalone (H.laevigata) revealed that apparent digestibility of crude protein (ADCP) measured using yttrium and ytterbium in hybrid abalone were significantly different across the treatments. Protein digestibility measured in experimental tanks was higher than those measured in indoor and outdoor commercial tanks, regardless of inert marker used. Chromic oxide led to overestimated ADCP compared to when measured using yttrium and ytterbium. There were no significant interactions between temperature and inert markers when measuring ADCP and apparent digestibility of gross energy (ADGE). However, there was a significant difference of ADCP amongst inert markers when measured in greenlip abalone cultured at two temperatures. While measurements of ADge calculated using three inert markers shared the same value.

An efficient water conditioning system for land-based abalone aquaculture

Energy Technology Data Exchange (ETDEWEB)

Davis, C.P. [University of Edinburgh (United Kingdom). School of GeoSciences; Carrington, C.G. [University of Otago, Dunedin (New Zealand). Dept. of Physics

2005-07-01

Data collected from a single grow-out tank in an abalone farm in southern New Zealand has highlighted hygiene maintenance problems in the use of semi-closed water conditioning systems for the aquaculture of New Zealand black foot abalone Haliotis iris. The data shows that semi-closed systems can have high concentrations of un-ionized ammonia, which is harmful to the animals. In this paper an alternative open flow-through system is suggested where energy demand is limited by heat recovery at the grow-out tank outlet. Using temperature data collected over 1 year, and a previously obtained expression for standing losses, a simple energy model is presented for an open system with heat recovery. To compliment the energy model, a function has been established for abalone production with respect to the concentration of un-ionized ammonia and water temperature. The energy model and production function are combined to determine the impact of plant design and tank conditions on the economics of the operation for the southern New Zealand climate. It is demonstrated that temperature control is financially preferable to an open system with no temperature control, and estimates of optimum operating conditions are given. (author)

Effect of air-temperature and diet composition on the drying process of pellets for japanese abalone (Haliotis discus hannai feeding

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Antonio Vega-Gálvez

2011-09-01

Full Text Available The aim of this research was to study the effect of air-temperature and diet composition on the mass transfer kinetics during the drying process of pellets used for Japanese Abalone (Haliotis discus hannai feeding. In the experimental design, three temperatures were used for convective drying, as well as three different diet compositions (Diets A, B and C, in which the amount of fishmeal, spirulin, algae, fish oil and cornstarch varied. The water diffusion coefficient of the pellets was determined using the equation of Fick's second law, which resulted in values between 0.84-1.94×10-10 m²/s. The drying kinetics was modeled using Page, Modified Page, Root of time, Exponential, Logarithmic, Two-Terms, Modified Henderson-Pabis and Weibull models. In addition, two new models, referred to as 'Proposed' models 1 and 2, were used to simulate this process. According to the statistical tests applied, the models that best fitted the experimental data were Modified Henderson-Pabis, Weibull and Proposed model 2, respectively. Bifactorial analysis of variance ANOVA showed that Diet A (fishmeal 44%, spirulin 9%, fish oil 1% and cornstarch 36% presented the highest diffusion coefficient values, which were favored by the temperature increase in the drying process.

Calcifying algae maintain settlement cues to larval abalone following algal exposure to extreme ocean acidification.

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O'Leary, Jennifer K; Barry, James P; Gabrielson, Paul W; Rogers-Bennett, Laura; Potts, Donald C; Palumbi, Stephen R; Micheli, Fiorenza

2017-07-18

Ocean acidification (OA) increasingly threatens marine systems, and is especially harmful to calcifying organisms. One important question is whether OA will alter species interactions. Crustose coralline algae (CCA) provide space and chemical cues for larval settlement. CCA have shown strongly negative responses to OA in previous studies, including disruption of settlement cues to corals. In California, CCA provide cues for seven species of harvested, threatened, and endangered abalone. We exposed four common CCA genera and a crustose calcifying red algae, Peyssonnelia (collectively CCRA) from California to three pCO 2 levels ranging from 419-2,013 µatm for four months. We then evaluated abalone (Haliotis rufescens) settlement under ambient conditions among the CCRA and non-algal controls that had been previously exposed to the pCO 2 treatments. Abalone settlement and metamorphosis increased from 11% in the absence of CCRA to 45-69% when CCRA were present, with minor variation among CCRA genera. Though all CCRA genera reduced growth during exposure to increased pCO 2 , abalone settlement was unaffected by prior CCRA exposure to increased pCO 2 . Thus, we find no impacts of OA exposure history on CCRA provision of settlement cues. Additionally, there appears to be functional redundancy in genera of CCRA providing cues to abalone, which may further buffer OA effects.

Pyrosequencing of Haliotis diversicolor transcriptomes: insights into early developmental molluscan gene expression.

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Zi-Xia Huang

Full Text Available BACKGROUND: The abalone Haliotis diversicolor is a good model for study of the settlement and metamorphosis, which are widespread marine ecological phenomena. However, information on the global gene backgrounds and gene expression profiles for the early development of abalones is lacking. METHODOLOGY/PRINCIPAL FINDINGS: In this study, eight non-normalized and multiplex barcode-labeled transcriptomes were sequenced using a 454 GS system to cover the early developmental stages of the abalone H. diversicolor. The assembly generated 35,415 unigenes, of which 7,566 were assigned GO terms. A global gene expression profile containing 636 scaffolds/contigs was constructed and was proven reliable using qPCR evaluation. It indicated that there may be existing dramatic phase transitions. Bioprocesses were proposed, including the 'lock system' in mature eggs, the collagen shells of the trochophore larvae and the development of chambered extracellular matrix (ECM structures within the earliest postlarvae. CONCLUSION: This study globally details the first 454 sequencing data for larval stages of H. diversicolor. A basic analysis of the larval transcriptomes and cluster of the gene expression profile indicates that each stage possesses a batch of specific genes that are indispensable during embryonic development, especially during the two-cell, trochophore and early postlarval stages. These data will provide a fundamental resource for future physiological works on abalones, revealing the mechanisms of settlement and metamorphosis at the molecular level.

The early stages of the immune response of the European abalone Haliotis tuberculata to a Vibrio harveyi infection.

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Cardinaud, Marion; Dheilly, Nolwenn M; Huchette, Sylvain; Moraga, Dario; Paillard, Christine

2015-08-01

Vibrio harveyi is a marine bacterial pathogen responsible for episodic abalone mortalities in France, Japan and Australia. In the European abalone, V. harveyi invades the circulatory system in a few hours after exposure and is lethal after 2 days of infection. In this study, we investigated the responses of European abalone immune cells over the first 24 h of infection. Results revealed an initial induction of immune gene expression including Rel/NF-kB, Mpeg and Clathrin. It is rapidly followed by a significant immuno-suppression characterized by reduced cellular hemocyte parameters, immune response gene expressions and enzymatic activities. Interestingly, Ferritin was overexpressed after 24 h of infection suggesting that abalone attempt to counter V. harveyi infection using soluble effectors. Immune function alteration was positively correlated with V. harveyi concentration. This study provides the evidence that V. harveyi has a hemolytic activity and an immuno-suppressive effect in the European abalone. Copyright © 2015 Elsevier Ltd. All rights reserved.

GROW-OUT OF ABALONE Haliotis squamata IN FLOATING CAGES FED DIFFERENT PROPORTIONS OF SEAWEED AND WITH REDUCTION OF STOCKING DENSITY

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I Nyoman Adiasmara Giri

2014-06-01

Full Text Available Abalone is a herbivore marine animal which feeds on seaweed. Abalone culture has a good prospect in terms of price, market share and simple culture technique. Thus, a study was conducted with the aim of finding out an effective and efficient abalone culture technique in terms of feed use and density. In this study, a 42 cm diameter plastic container with a 22 cm height was used. Three vertically arranged containers were used as the experimental group which were put into a net box and hung onto a raft so that the containers were placed in a 4 m depth below the sea surface. The juvenile of abalones being used came from a hatchery production that has been adapted to cages environment with Gracilaria sp. and Ulva sp. feed. The initial density of abalones was 450 for each container, with the initial weight of 2.6-3.2 g and the 2.5-2.7 cm shell lengths. The abalones were fed with Gracilaria sp. and Ulva sp. seaweeds with different Gracilaria sp./Ulva sp. proportions, i.e. 100/0% (A; 80/20% (B; and 60/40% (C as the treatments. Each treatment consisted of two replications. After three months of rearing period, densities of abalones were reduced to be 190 for each experimental unit. Weight and shell length of abalones were measured every month by measuring 25 abalone samples from each experimental unit. The result of the experiment showed that the increase in the Ulva sp. proportion in the feed increased the growth of abalones and decreased the feed conversion. Feeding with Gracilaria sp./Ulva sp. proportion of 60%/40% allowed the best growth of abalones. The decrease of abalone density in the experimental unit after three months of rearing also produced an increase in their growth.

Structural and functional biological materials: Abalone nacre, sharp materials, and abalone foot adhesion

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Lin, Albert Yu-Min

A three-part study of lessons from nature is presented through the examination of various biological materials, with an emphasis on materials from the mollusk Haliotis rufescens, commonly referred to as the red abalone. The three categories presented are: structural hierarchy, self-assembly, and functionality. Ocean mollusk shells are composed of aragonite/calcite crystals interleaved with layers of a visco-elastic protein, having dense, tailored structures with excellent mechanical properties. The complex nano-laminate structure of this bio-composite material is characterized and related to its mechanical properties. Three levels of structural hierarchy are identified: macroscale mesolayers separating larger regions of tiled aragonite, microscale organization of 0.5 mum by 10 mum aragonite bricks; nanoscale mineral bridges passing through 30 nm layers of organic matrix separating individual aragonite tiles. Composition and growth mechanisms of this nanostructure were observed through close examination of laboratory-grown samples using scanning electron microscopy (SEM), Raman spectroscopy, and transmission electron microscopy (TEM). Glass slides and nacre pucks were implanted onto the growth surface of living abalone and removed periodically to observe trends in nacre deposition. Various deproteinization and demineralization experiments are used to explore the inorganic and organic components of the nacre's structure. The organic component of the shell is characterized by atomic force microscopy (AFM). The functionality of various biological materials is described and investigated. Two specific types of functionality are characterized, the ability of some materials to cut and puncture through sharp designs, and the ability for some materials to be used as attachment devices. Aspects of cutting materials employed by a broad range of animals were characterized and compared. In respect to the attachment mechanisms the foot of the abalone and the tree frog were

Setting realistic recovery targets for two interacting endangered species, sea otter and northern abalone.

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Chadès, Iadine; Curtis, Janelle M R; Martin, Tara G

2012-12-01

Failure to account for interactions between endangered species may lead to unexpected population dynamics, inefficient management strategies, waste of scarce resources, and, at worst, increased extinction risk. The importance of species interactions is undisputed, yet recovery targets generally do not account for such interactions. This shortcoming is a consequence of species-centered legislation, but also of uncertainty surrounding the dynamics of species interactions and the complexity of modeling such interactions. The northern sea otter (Enhydra lutris kenyoni) and one of its preferred prey, northern abalone (Haliotis kamtschatkana), are endangered species for which recovery strategies have been developed without consideration of their strong predator-prey interactions. Using simulation-based optimization procedures from artificial intelligence, namely reinforcement learning and stochastic dynamic programming, we combined sea otter and northern abalone population models with functional-response models and examined how different management actions affect population dynamics and the likelihood of achieving recovery targets for each species through time. Recovery targets for these interacting species were difficult to achieve simultaneously in the absence of management. Although sea otters were predicted to recover, achieving abalone recovery targets failed even when threats to abalone such as predation and poaching were reduced. A management strategy entailing a 50% reduction in the poaching of northern abalone was a minimum requirement to reach short-term recovery goals for northern abalone when sea otters were present. Removing sea otters had a marginally positive effect on the abalone population but only when we assumed a functional response with strong predation pressure. Our optimization method could be applied more generally to any interacting threatened or invasive species for which there are multiple conservation objectives. © 2012 Society for

Polarization-dependent imaging contrast in abalone shells

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Metzler, Rebecca A.; Zhou, Dong; Abrecht, Mike; Chiou, Jau-Wern; Guo, Jinghua; Ariosa, Daniel; Coppersmith, Susan N.; Gilbert, P. U. P. A.

2008-02-01

Many biominerals contain micro- or nanocrystalline mineral components, organized accurately into architectures that confer the material with improved mechanical performance at the macroscopic scale. We present here an effect which enables us to observe the relative orientation of individual crystals at the submicron scale. We call it polarization-dependent imaging contrast (PIC), as it is an imaging development of the well-known x-ray linear dichroism. Most importantly, PIC is obtained in situ, in biominerals. We present here PIC in the prismatic and nacreous layers of Haliotis rufescens (red abalone), confirm it in geologic calcite and aragonite, and corroborate the experimental data with theoretical simulated spectra. PIC reveals different and unexpected aspects of nacre architecture that have inspired theoretical models for nacre formation.

Anti-Coagulant and Anti-Thrombotic Properties of Blacklip Abalone (Haliotis rubra): In Vitro and Animal Studies.

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Suleria, Hafiz Ansar Rasul; Masci, Paul P; Zhao, Kong-Nan; Addepalli, Rama; Chen, Wei; Osborne, Simone A; Gobe, Glenda C

2017-08-04

Sulphated polysaccharides with anti-thrombotic and anti-coagulant activities have been found in various marine biota. In this study, a previously characterised anti-thrombotic and anti-coagulant extract from blacklip abalone was fractionated by anion exchange chromatography (AEC), pooled (on a sulphated polysaccharide basis) and administered to Wistar rats via oral gavage (N = 8) for assessment as an oral therapeutic. To ensure that the preparation had anti-coagulant activity prior to oral administration, it was assessed in rat blood by thromboelastography (TEG) significantly increasing reaction (R) time (or time until clot formation). Following in vitro confirmation of anti-coagulant activity, 40 mg of the preparation was orally administered to rats with blood samples collected at 2, 4, and 6 h post-gavage. Assessment of all blood samples by TEG showed some prolongation of R time from 355 to 380 s after 4 h. Dosing of the post-gavage blood samples with the abalone preparation to confirm anti-thrombotic activity in vitro revealed residual anti-coagulant activity, further suggesting that oral administration did increase anti-coagulant potential in the collected blood but that bioavailability was low. Assessment of tissues and haematological parameters showed no obvious harmful effects of the abalone preparation in animals. In summary, even though oral administration of fractionated and pooled blacklip abalone extract to rats delayed clotting after 4 h, bioavailability of the preparation appeared to be low and may be more appropriate for intravenous administration as an anti-thrombotic or anti-coagulant therapeutic.

A Novel Aldo-Keto Reductase, HdRed, from the Pacific Abalone Haliotis discus hannai, Which Reduces Alginate-derived 4-Deoxy-L-erythro-5-hexoseulose Uronic Acid to 2-Keto-3-deoxy-D-gluconate.

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Mochizuki, Shogo; Nishiyama, Ryuji; Inoue, Akira; Ojima, Takao

2015-12-25

Abalone feeds on brown seaweeds and digests seaweeds' alginate with alginate lyases (EC 4.2.2.3). However, it has been unclear whether the end product of alginate lyases (i.e. unsaturated monouronate-derived 4-deoxy-L-erythro-5-hexoseulose uronic acid (DEH)) is assimilated by abalone itself, because DEH cannot be metabolized via the Embden-Meyerhof pathway of animals. Under these circumstances, we recently noticed the occurrence of an NADPH-dependent reductase, which reduced DEH to 2-keto-3-deoxy-D-gluconate, in hepatopancreas extract of the pacific abalone Haliotis discus hannai. In the present study, we characterized this enzyme to some extent. The DEH reductase, named HdRed in the present study, could be purified from the acetone-dried powder of hepatopancreas by ammonium sulfate fractionation followed by conventional column chromatographies. HdRed showed a single band of ∼ 40 kDa on SDS-PAGE and reduced DEH to 2-keto-3-deoxy-D-gluconate with an optimal temperature and pH at around 50 °C and 7.0, respectively. HdRed exhibited no appreciable activity toward 28 authentic compounds, including aldehyde, aldose, ketose, α-keto-acid, uronic acid, deoxy sugar, sugar alcohol, carboxylic acid, ketone, and ester. The amino acid sequence of 371 residues of HdRed deduced from the cDNA showed 18-60% identities to those of aldo-keto reductase (AKR) superfamily enzymes, such as human aldose reductase, halophilic bacterium reductase, and sea hare norsolorinic acid (a polyketide derivative) reductase-like protein. Catalytic residues and cofactor binding residues known in AKR superfamily enzymes were fairly well conserved in HdRed. Phylogenetic analysis for HdRed and AKR superfamily enzymes indicated that HdRed is an AKR belonging to a novel family. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

A Novel Aldo-Keto Reductase, HdRed, from the Pacific Abalone Haliotis discus hannai, Which Reduces Alginate-derived 4-Deoxy-l-erythro-5-hexoseulose Uronic Acid to 2-Keto-3-deoxy-d-gluconate*

Science.gov (United States)

Mochizuki, Shogo; Nishiyama, Ryuji; Inoue, Akira; Ojima, Takao

2015-01-01

Abalone feeds on brown seaweeds and digests seaweeds' alginate with alginate lyases (EC 4.2.2.3). However, it has been unclear whether the end product of alginate lyases (i.e. unsaturated monouronate-derived 4-deoxy-l-erythro-5-hexoseulose uronic acid (DEH)) is assimilated by abalone itself, because DEH cannot be metabolized via the Embden-Meyerhof pathway of animals. Under these circumstances, we recently noticed the occurrence of an NADPH-dependent reductase, which reduced DEH to 2-keto-3-deoxy-d-gluconate, in hepatopancreas extract of the pacific abalone Haliotis discus hannai. In the present study, we characterized this enzyme to some extent. The DEH reductase, named HdRed in the present study, could be purified from the acetone-dried powder of hepatopancreas by ammonium sulfate fractionation followed by conventional column chromatographies. HdRed showed a single band of ∼40 kDa on SDS-PAGE and reduced DEH to 2-keto-3-deoxy-d-gluconate with an optimal temperature and pH at around 50 °C and 7.0, respectively. HdRed exhibited no appreciable activity toward 28 authentic compounds, including aldehyde, aldose, ketose, α-keto-acid, uronic acid, deoxy sugar, sugar alcohol, carboxylic acid, ketone, and ester. The amino acid sequence of 371 residues of HdRed deduced from the cDNA showed 18–60% identities to those of aldo-keto reductase (AKR) superfamily enzymes, such as human aldose reductase, halophilic bacterium reductase, and sea hare norsolorinic acid (a polyketide derivative) reductase-like protein. Catalytic residues and cofactor binding residues known in AKR superfamily enzymes were fairly well conserved in HdRed. Phylogenetic analysis for HdRed and AKR superfamily enzymes indicated that HdRed is an AKR belonging to a novel family. PMID:26555267

Monomorphic pathogens: The case of Candidatus Xenohaliotis californiensis from abalone in California, USA and Baja California, Mexico.

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Cicala, Francesco; Moore, James D; Cáceres-Martínez, Jorge; Del Río-Portilla, Miguel A; Hernández-Rodríguez, Mónica; Vásquez-Yeomans, Rebeca; Rocha-Olivares, Axayácatl

2018-05-01

Withering syndrome (WS) is a chronic wasting disease affecting abalone species attributed to the pathogen Candidatus Xenohaliotis californiensis (CXc). Wild populations of blue (Haliotis fulgens) and yellow (H. corrugata) abalone have experienced unusual mortality rates since 2009 off the peninsula of Baja California and WS has been hypothesized as a possible cause. Currently, little information is available about the genetic diversity of CXc and particularly the possible existence of strains differing in pathogenicity. In a recent phylogenetic analysis, we characterized five coding genes from this rickettsial pathogen. Here, we analyze those genes and two additional intergenic non-coding regions following multi-locus sequence typing (MLST) and multi-spacer typing (MST) approaches to assess the genetic variability of CXc and its relationship with blue, yellow and red (H. rufescens) abalone. Moreover, we used 16S rRNA pyrosequencing reads from gut microbiomes of blue and yellow abalone to complete the genetic characterization of this prokaryote. The presence of CXc was investigated in more than 150 abalone of the three species; furthermore, a total of 385 DNA sequences and 7117 16S rRNA reads from Candidatus Xenohaliotis californiensis were used to evaluate its population genetic structure. Our findings suggest the absence of polymorphism in the DNA sequences of analyzed loci and the presence of a single lineage of CXc infecting abalone from California (USA) and Baja California (Mexico). We posit that the absence of genetic variably in this marine rickettsia may be the result of evolutionary and ecological processes. Copyright © 2018 Elsevier Inc. All rights reserved.

Structural characterization and expression analysis of a beta-thymosin homologue (Tβ) in disk abalone, Haliotis discus discus.

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Kasthuri, Saranya Revathy; Premachandra, H K A; Umasuthan, Navaneethaiyer; Whang, Ilson; Lee, Jehee

2013-09-15

Repertoires of proteins and small peptides play numerous physiological roles as hormones, antimicrobial peptides, and cellular signaling factors. The beta-thymosins are a group of small acidic peptides involved in processes such as actin sequestration, neuronal development, wound healing, tissue repair, and angiogenesis. Recent characterization of the beta thymosins as immunological regulators in invertebrates led to our identification and characterization of a beta-thymosin homologue (Tβ) from Haliotis discus discus. The cDNA possessed an ORF of 132 bp encoding a protein of 44 amino acids with a molecular mass of 4977 Da. The amino acid sequence shows high identity with another molluskan beta-thymosin and has a characteristic actin binding motif (LKKTET) and glutamyl donors. Phylogenetic analysis showed a close relationship with molluskan homologues, as well as its distinct identity and common ancestral origin. Genomic analysis revealed a 3 exon-2 intron structure similar to the other homologues. In silico promoter analysis also revealed significant transcription factor binding sites, providing evidence for the expression of this gene under different cellular conditions, including stress or pathogenic attack. Tissue distribution profiling revealed a ubiquitous presence in all the examined tissues, but with the highest expression in mantle and hemocyte. Immune challenge with lipopolysaccharide, poly I:C and Vibrio parahemolyticus induced beta-thymosin expression in gill and hemocytes, affirming an immune-related role in invertebrates. Copyright © 2013 Elsevier B.V. All rights reserved.

Rapidly evolving zona pellucida domain proteins are a major component of the vitelline envelope of abalone eggs

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Aagaard, Jan E.; Yi, Xianhua; MacCoss, Michael J.; Swanson, Willie J.

2006-01-01

Proteins harboring a zona pellucida (ZP) domain are prominent components of vertebrate egg coats. Although less well characterized, the egg coat of the non-vertebrate marine gastropod abalone (Haliotis spp.) is also known to contain a ZP domain protein, raising the possibility of a common molecular basis of metazoan egg coat structures. Egg coat proteins from vertebrate as well as non-vertebrate taxa have been shown to evolve under positive selection. Studied most extensively in the abalone system, coevolution between adaptively diverging egg coat and sperm proteins may contribute to the rapid development of reproductive isolation. Thus, identifying the pattern of evolution among egg coat proteins is important in understanding the role these genes may play in the speciation process. The purpose of the present study is to characterize the constituent proteins of the egg coat [vitelline envelope (VE)] of abalone eggs and to provide preliminary evidence regarding how selection has acted on VE proteins during abalone evolution. A proteomic approach is used to match tandem mass spectra of peptides from purified VE proteins with abalone ovary EST sequences, identifying 9 of 10 ZP domain proteins as components of the VE. Maximum likelihood models of codon evolution suggest positive selection has acted among a subset of amino acids for 6 of these genes. This work provides further evidence of the prominence of ZP proteins as constituents of the egg coat, as well as the prominent role of positive selection in diversification of these reproductive proteins. PMID:17085584

The role of hybridization in improving the immune response and thermal tolerance of abalone.

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Liang, Shuang; Luo, Xuan; You, Weiwei; Luo, Lianzhong; Ke, Caihuan

2014-07-01

Recently, frequent death of cultured abalone drew our attention to the stress tolerance of abalone. Hybridization is an effective way of genetic improvement in aquaculture, which can introduce improved traits to the hybrids. In this study, we challenged the hybrids between Haliotis discus hannai and Haliotis gigantea, and their parents with bacteria (vibrio harveyi, vibrio alginolyticus and vibrio parahemolyticus), then held them at 20 °C and 28 °C, survival rates of the parental populations and hybrid populations were recorded. Then we tested the immune responses and thermal-induced responses of the four populations at different temperatures. Total hemocyte count (THC), respiratory burst, superoxide dismutase activity (SOD), acid phosphatase activity (ACP), alkaline phosphatase activity (AKP), myeloperoxidase activity (MPO), and HSP70 expression were determined on day 1 and day 7 of the temperature exposure. Results showed higher survival rates of the hybrids than their parents against bacteria challenge. For immune parameters, THCs were evaluated at 28 °C, while increased THC was also observed in H. discus hannai ♀ × H. gigantea ♂ (DG) and H. discus hannai ♀ × H. discus hannai ♂ (DD) at 12 °C (day 7); at 28 °C, respiratory burst was activated (day 1 and 7), while SOD activity first rose then fell over 7-days exposure; AKP activity was elevated at 12 °C and 28 °C (day 1), most notably in DG, and an increased level of ACP was observed in DG at 28 °C (day 7); MPO activity was suppressed at 12 °C and 28 °C on day 1, but recovered on day 7. For HSP70, increased HSP70 levels were observed in all populations at 28 °C (day 1), and DD got the lowest HSP70 level after 7-days exposure at 28 °C. Overall, the results suggest that temperature changes could significantly affect the physiological status of abalone, and hybrids may be more resistant to disease and thermal stresses than their parents. Copyright © 2014 Elsevier Ltd. All rights reserved.

Effects of waterborne nickel on the physiological and immunological parameters of the Pacific abalone Haliotis discus hannai during thermal stress.

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Min, Eun Young; Cha, Yong-Joo; Kang, Ju-Chan

2015-09-01

In this study, the 96-h LC50 at 22 and 26 °C values was 28.591 and 11.761 mg/L, respectively, for NiCl2 exposure in the abalone. The alteration of physiological and immune-toxicological parameters such as the total hemocyte count (THC), lysozyme, phenoloxidase (PO), and phagocytosis activity was measured in the abalone exposed to nickel (200 and 400 μg/L) under thermal stress for 96 h. In this study, Mg and THC decreased, while Ca, lysozyme, PO, and phagocytosis activity increased in the hemolymph of Pacific abalone exposed to NiCl2 when compared to a control at both 22 and 26 °C. However, these parameters were not affected by a rise in temperature from 22 to 26 °C in non-exposed groups. Our results showed that NiCl2 below 400 μg/L was able to stimulate immune responses in abalone. However, complex stressors, thermal changes, or NiCl2 can modify the immunological response and lead to changes in the physiology of host-pollutant interactions in the abalone.

Comparison of polysaccharides of Haliotis discus hannai and Volutharpa ampullacea perryi by PMP-HPLC-MS(n) analysis upon acid hydrolysis.

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Wang, Hongxu; Zhao, Jun; Li, Dongmei; Wen, Chengrong; Liu, Haiman; Song, Shuang; Zhu, Beiwei

2015-10-13

Haliotis discus hannai Ino (Haliotis) is a highly valued marine shellfish, and it is sometimes replaced by another cheaper Gastropoda mollusk, Volutharpa ampullacea perryi (Volutharpa). Polysaccharides from pleopods, viscera and gonads of these two gastropods were compared by analyzing the mono- and di-saccharides in their acid hydrolysates using high performance liquid chromatography-mass spectrometry (HPLC-MS(n)) after 1-phenyl-3-methyl-5-pyrazolone (PMP) derivatization. Disaccharide analysis revealed the distribution of uronic acid-containing polysaccharides (UACPs) in the biological samples. GlcA-(1 → 2)-Man, GlcA-(1 → 3)-GalN, and another disaccharide consisting of a hexuronic acid linked to a hexose were found in the hydrolysates, which indicated the existence of AGSP (abalone gonad sulfated polysaccharide) with the backbone composed of → 2)-α-Man(1 → 4)-β-GlcA(1 → repeating unit, AAP (abalone glycosaminoglycan-like polysaccharide) with the backbone of → 3)-GalNAc-(1 → 2)-GlcA-(1 → 3)-GalNAc-(1 → 4)-GlcA-(1 → repeating unit, and unidentified DS1P containing a hexuronic acid linked to a hexose unit, respectively. As shown by extracted ion chromatograms (XICs), AAP was the only UACP found in pleopods of the two gastropods; gonads and viscera of Haliotis contained DS1P and AGSP, while those of Volutharpa contained DS1P, AGSP as well as AAP. Monosaccharides in the acid hydrolysates were demonstrated in XICs by extracting their corresponding PMP derivative quasi-molecular ions one by one, and the results indicated the similar conclusion to the disaccharide analysis. Therefore, it could be concluded that polysaccharides from pleopods of the two gastropods are very similar, while those from their viscera and gonads differ greatly. Copyright © 2015 Elsevier Ltd. All rights reserved.

AKTIVITAS ENZIM KOMERSIAL, EKSTRAK KASAR ENZIM DARI VISCERA KEONG MAS (Pila polita, ABALON (Haliotis asinina, DAN BEKICOT (Achatina fulica UNTUK LISIS JARINGAN RUMPUT LAUT Kappaphycus alvarezii PADA KULTUR PROTOPLAS

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Sri Redjeki Hesti Mulyaningrum

2008-12-01

Full Text Available Dalam usaha perbaikan kualitas bibit rumput laut Kappaphycus alvarezii dilakukan kultur protoplas dengan isolasi protoplas menggunakan enzim. Untuk mendapatkan sumber enzim yang ekonomis sebagai alternatif pengganti enzim komersial dan untuk mengetahui perbandingan konsentrasi enzim komersial yang optimum agar menghasilkan jumlah protoplas yang maksimum, dilakukan karakterisasi terhadap enzim dari berbagai sumber. Aktivitas ekstrak kasar enzim dari viscera bekicot (Achatina fulica tidak berbeda nyata dengan enzim komersial (P>0,05 dengan aktivitas sebesar 0,729 unit/mL; enzim komersial 0,354 unit/mL; ekstrak kasar enzim dari viscera keong mas (Pila polita 0,048 unit/mL; dan ekstrak kasar enzim dari viscera abalon (Haliotis asinina 0,014 unit/mL. Perbandingan enzim komersial yang optimum adalah 2:1 menghasilkan protoplas sebanyak 1,26 x 108 sel/mL; kemudian 1:2 dengan jumlah protoplas 1,22 x 108 sel/mL; perbandingan 1:1 menghasilkan protoplas sebanyak 8,36 x 107 sel/mL; perbandingan 0:1 menghasilkan protoplas sebanyak 6,33 x 107 sel/mL; dan perbandingan 1:0 menghasilkan protoplas sebanyak 9,55 x 106 sel/mL. Rumput laut asal Takalar memiliki protoplas dengan kepadatan tertinggi sebesar 3,7 x 108 sel/mL. Effort to improve the quality of seaweed seed Kappaphycus alvarezii has been done by protoplast culture with protoplast isolation using enzyme. To find out economical enzyme sources as alternatives to substitute the expensive commercial enzyme and to determine the optimum concentration ratio of commercial enzyme to produce maximum amount of protoplast, characterization was executed to several potential sources. Activity of crude extract enzyme from viscera of garden snail (Achatina fulica was not significantly different with commercial enzyme (P>0.05 it was 0.729 unit/mL, commercial enzyme 0.354 unit/mL activity; crude extract enzyme from viscera of golden snail (Pila polita 0.048 unit/mL activity and crude extract enzyme from viscera of abalone

Nutrient uptake efficiency of Gracilaria chilensis and Ulva lactuca in an IMTA system with the red abalone Haliotis rufescens

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Juan Macchiavello

2014-07-01

Full Text Available The current study examined the nutrient uptake efficiency of Ulva lactuca and Gracilaria chilensis cultivated in tanks associated with the wastewater of a land-based abalone culture. The experiments evaluated different seaweed stocking densities (1200, 1900, 2600, and 3200 g m-2 and water exchange rates (60, 80, 125, and 250 L h-1. The results show that both U. lactuca and G. chilensis were efficient in capturing and removing all of the inorganic nutrients originating from the abalone cultivation for all of the tested conditions. Furthermore, an annual experiment was performed with U. lactuca, cultivated at a stocking density of 1900 g m-2 and at a water exchanged rate of 125 L h-1, in order to evaluate seasonal changes in the nutrient uptake efficiency, productivity, and growth rate associated with the wastewater of a land-based abalone culture. The results confirmed high uptake efficiency during the entire year, equivalent to a 100% removal of the NH4, NO3, and PO4 produced by the land-based abalone culture. The growth rate and productivity of U. lactuca presented a marked seasonality, increasing from fall until summer and varying from 0.5 ± 0.2% to 2.6 ± 0.2% d-1 and 10 ± 6.1% to 73.6 ± 8.4% g m-2 d-1 for sustainable growth rate and productivity, respectively. We conclude that there is sufficient evidence that demonstrates the high possibility of changing the traditional monoculture system of abalone in Chile, to a sustainable integrated multi-trophic aquaculture system, generating positive environmental externalities, including the use of U. lactuca as a biofiltration unit.

皱纹盘鲍（Haliotis discus hannai）肠道潜在益生菌的筛选及对幼鲍生长的影响*%SELECTION OF POTENTIAL PROBIOTICS FROM ABALONE INTESTIONAL AND THEIR EFFECTS ON GROWTH OF JUVENILE SMALL ABALONE HALIOTIS DISCUS HANNAI

Institute of Scientific and Technical Information of China (English)

姜海峰; 刘小林; 常亚青; 冷晓飞; 李丹; 王高学

2013-01-01

　　采用体外实验筛选益生菌结合16S rDNA序列分析法,从124株不具有溶血作用的皱纹盘鲍(Haliotis discus hannai)肠道细菌中筛选得到5株潜在益生菌并进行了分子鉴定,进一步对5株潜在益生菌进行了安全性实验及体内饲喂实验。结果表明,2株具有拮抗哈维弧菌和灿烂弧菌能力的潜在益生菌分别被鉴定为Shewanella sp.(WA64)和Shewanella sp.(WA65),一株产海藻酸酶和淀粉酶的潜在益生菌被鉴定为Vibrio sp.(WA51),产蛋白酶潜在益生菌被鉴定为 Bacillus sp.(FA12),产琼脂酶潜在益生菌被鉴定为Tamlana sp.(FA86)；安全性实验表明5株潜在益生菌在107cfu/ml下对皱纹盘鲍没有明显的毒害作用；通过体内饲喂实验发现,潜在益生菌 WA64、WA65的复合作用能够显著提高幼鲍增重率和存活率(P<0.05),并在生产条件下能够明显降低幼鲍的死亡量。经抗生素敏感性实验, WA64菌株对15种抗生素均敏感或中度敏感, WA65菌株仅对庆大霉素和链霉素2种抗生素产生耐药。%Five strains of potential probiotics isolated from 124 non-hemolysis strains of the GI of abalone in vitro were identified by 16S rDNA sequence analysis. In addition, pathogenicity and feeding experiment were conducted. Results show that Strain WA64 and WA65 which exhibit inhibitory effects against Vibrio harveyi, Vibrio splendidus are identified as Shewanella;WA51 produced amylase and alginase is identified as Vibrio;FA123 produced protease is identified as Ba-cillus; FA86 produced agarase is identified as Tamlana. Potential probiotics are safe to abalone under 107cfu/ml. Feeding experiment showed the weight gain ratio and survival rate were significantly increased in treatment supplemented with WA64 and WA65 (P<0.05). Furthermore, the effects of WA64 and WA65 in pilot scale trials show the mortality of juvenile small abalone decreases obviously. Antibiotic sensitivity assays revealed that strain WA64 was sensitive or

Speciation of Bio-Available Iodine in Abalone (Haliotis discus hannai) by High-Performance Liquid Chromatography Hyphenated with Inductively Coupled Plasma-Mass Spectrometry Using an In Vitro Method.

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Doh, Han Sol; Park, Hyun Jin

2018-06-01

Abalone is one of the most valuable marine products found in East Asia because it is rich in nutritious substances including iodine. In this study, the in vitro dialyzability approach was used to assess the bio-available iodine species in abalone. Iodide, iodate, 3-iodo-L-tyrosine (MIT), and 3,5-diiodo-L-tyrosine (DIT) were separated by high-performance liquid chromatography hyphenated with inductively coupled plasma-mass spectrometry (HPLC-ICP-MS). To assure the consistency, reliability, and accuracy of the data, the method was validated. Comparison of the total iodine in abalone muscle and viscera indicated that abalone muscle showed greater digestion/absorption efficiency than abalone viscera (digestion efficiency: 68.13 ± 2.59% and 47.88 ± 5.76% and absorption efficiency: 59.78 ± 2.93% and 35.12 ± 1.43% for abalone viscera and muscle, respectively). However, evaluation of the sum of the analyzed iodine species targeted in this study by HPLC-ICP-MS indicated that abalone muscle showed lower digestion efficiency and similar absorption efficiency compared to that of abalone viscera (digestion efficiency: 35.52 ± 5.41% and 28.84 ± 1.83%; absorption efficiency: 23.56 ± 4.38% and 27.56 ± 1.51% for abalone viscera and muscle, respectively). The main forms of iodine detected in abalone muscle were iodide and MIT, whereas iodide was the major form in abalone viscera. The bio-available iodine in abalone was quantified via an in vitro method employing HPLC-ICP-MS. The results of this study indicated that abalone is feasible as a new iodine source and may prospectively find application in iodine-fortified foods. © 2018 Institute of Food Technologists®.

Experimental evidence for the effects of polyphenolic compounds from Dictyoneurum californicum Ruprecht (Phaeophyta: Laminariales) on feeding rate and growth in the red abalone Haliotus rufescens Swainson

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Winter, Frank C.; Estes, James A.

1992-01-01

The effects of polyphenolic compounds from brown algae on grazing and growth rate of the California red abalone Haliotis rufescens Swainson were examined. Abalone consumed three phenolic-poor algal species, Laminaria sinclarii (Harvey) Farlow, Macrocystis pyrifera Agardh, and Nereocystis luetkeana Postels et Ruprecht (mean phenolic content = 0.52% dry mass), at a greater rate than two phenolic-rich species, Dictyoneurum californicum Ruprecht and Cystoseira osmundacea Agardh (mean phenolic content = 4.60% dry mass). This inverse relationship between phenolic content and consumption rate also existed after the algae were macerated and the liquid portion of the blended slurry incorporated in agar discs. However, the correlation between grazing rate and phenolic content imprpve d in this latter experiment, thus suggesting that abalone grazing was deterred significantly by the morphology of L. sinclarii and, to a lesser extent, of M. pyrifera. Polyphenolics extracted from D. californicum reduced abalone grazing rates by 90% when incorporated into agar discs at a concentration of 6 mg·ml−1. Although abalone were unable to maintain body mass when fed ad libitum on macerated M. pyrifera incorporated into agar discs, polyphenolics from D. californicum further inhibited shell growth when added to the discs at 5 mg·ml−1. The abalone ate less of the phenol-containing discs than of the discs lacking phenolics. Our results support findings of several prior studies that polyphenolic compounds from brown algae deter grazing by coastal zone herbivores in the northeast Pacific Ocean.

Relationships between and formation dynamics of the microbiota of consumers, producers, and the environment in an abalone aquatic system.

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Jiang, Jing-Zhe; Zhao, Wang; Liu, Guang-Feng; Wang, Jiang-Yong

2017-01-01

An ecosystem is a community comprising living and nonliving components of the environment. Microbes are ubiquitous elements in each of these components. The dynamics of microbiota formation in an ecosystem is important to elucidate, because how the different components of a system exchange microbes, and how the microbes control ecological processes remain unresolved. In this study, an abalone, Haliotis diversicolor, seed-nursing pond was used as a model system. We first examined changes in bacterial communities during the seedling cultivation of this herbivorous juvenile aquatic invertebrate animal. Denaturing gradient gel electrophoresis (DGGE) and pyrosequencing were used to analyze bacterial community dynamics and spatio-temporal interactions of different system components: consumers (abalone), producers (algae or a substrate), and the environment (water). DGGE fingerprints revealed that the developmental stages of abalone influences bacterial communities of both the abalone and substrate. Although the communities in water fluctuated daily, they could be divided into two clusters that coincided with abalone stages, reflecting the transition from larva to juvenile at around day 21. Pyrosequencing showed that the microbiota in the abalone and substrate had more operational taxonomic units in common than that of either with water. The Bray-Curtis similarity index was used to quantify the formation dynamics of microbiota among the various components of the system. The bacterial communities in producers and consumers showed similar changes. These communities were unstable at the beginning and then slowly stabilized over time. The environmental bacterial community was more stable than the bacterial communities in consumers and producers, and may have been the basis for stability in the system. Our research provides insights into the dynamics of microbiota formation in various biotic elements of a system that will contribute to predictive systems modeling.

Relationships between and formation dynamics of the microbiota of consumers, producers, and the environment in an abalone aquatic system.

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Jing-Zhe Jiang

Full Text Available An ecosystem is a community comprising living and nonliving components of the environment. Microbes are ubiquitous elements in each of these components. The dynamics of microbiota formation in an ecosystem is important to elucidate, because how the different components of a system exchange microbes, and how the microbes control ecological processes remain unresolved. In this study, an abalone, Haliotis diversicolor, seed-nursing pond was used as a model system. We first examined changes in bacterial communities during the seedling cultivation of this herbivorous juvenile aquatic invertebrate animal. Denaturing gradient gel electrophoresis (DGGE and pyrosequencing were used to analyze bacterial community dynamics and spatio-temporal interactions of different system components: consumers (abalone, producers (algae or a substrate, and the environment (water. DGGE fingerprints revealed that the developmental stages of abalone influences bacterial communities of both the abalone and substrate. Although the communities in water fluctuated daily, they could be divided into two clusters that coincided with abalone stages, reflecting the transition from larva to juvenile at around day 21. Pyrosequencing showed that the microbiota in the abalone and substrate had more operational taxonomic units in common than that of either with water. The Bray-Curtis similarity index was used to quantify the formation dynamics of microbiota among the various components of the system. The bacterial communities in producers and consumers showed similar changes. These communities were unstable at the beginning and then slowly stabilized over time. The environmental bacterial community was more stable than the bacterial communities in consumers and producers, and may have been the basis for stability in the system. Our research provides insights into the dynamics of microbiota formation in various biotic elements of a system that will contribute to predictive systems

Seasonal and algal diet-driven patterns of the digestive microbiota of the European abalone Haliotis tuberculata, a generalist marine herbivore.

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Gobet, Angélique; Mest, Laëtitia; Perennou, Morgan; Dittami, Simon M; Caralp, Claire; Coulombet, Céline; Huchette, Sylvain; Roussel, Sabine; Michel, Gurvan; Leblanc, Catherine

2018-03-27

Holobionts have a digestive microbiota with catabolic abilities allowing the degradation of complex dietary compounds for the host. In terrestrial herbivores, the digestive microbiota is known to degrade complex polysaccharides from land plants while in marine herbivores, the digestive microbiota is poorly characterized. Most of the latter are generalists and consume red, green, and brown macroalgae, three distinct lineages characterized by a specific composition in complex polysaccharides, which represent half of their biomass. Subsequently, each macroalga features a specific epiphytic microbiota, and the digestive microbiota of marine herbivores is expected to vary with a monospecific algal diet. We investigated the effect of four monospecific diets (Palmaria palmata, Ulva lactuca, Saccharina latissima, Laminaria digitata) on the composition and specificity of the digestive microbiota of a generalist marine herbivore, the abalone, farmed in a temperate coastal area over a year. The microbiota from the abalone digestive gland was sampled every 2 months and explored using metabarcoding. Diversity and multivariate analyses showed that patterns of the microbiota were significantly linked to seasonal variations of contextual parameters but not directly to a specific algal diet. Three core genera: Psychrilyobacter, Mycoplasma, and Vibrio constantly dominated the microbiota in the abalone digestive gland. Additionally, a less abundant and diet-specific core microbiota featured genera representing aerobic primary degraders of algal polysaccharides. This study highlights the establishment of a persistent core microbiota in the digestive gland of the abalone since its juvenile state and the presence of a less abundant and diet-specific core community. While composed of different microbial taxa compared to terrestrial herbivores, the digestive gland constitutes a particular niche in the abalone holobiont, where bacteria (i) may cooperate to degrade algal polysaccharides to

ZP Domain Proteins in the Abalone Egg Coat Include a Paralog of VERL under Positive Selection That Binds Lysin and 18-kDa Sperm Proteins

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Aagaard, Jan E.; Vacquier, Victor D.; MacCoss, Michael J.; Swanson, Willie J.

2010-01-01

Identifying fertilization molecules is key to our understanding of reproductive biology, yet only a few examples of interacting sperm and egg proteins are known. One of the best characterized comes from the invertebrate archeogastropod abalone (Haliotis spp.), where sperm lysin mediates passage through the protective egg vitelline envelope (VE) by binding to the VE protein vitelline envelope receptor for lysin (VERL). Rapid adaptive divergence of abalone lysin and VERL are an example of positive selection on interacting fertilization proteins contributing to reproductive isolation. Previously, we characterized a subset of the abalone VE proteins that share a structural feature, the zona pellucida (ZP) domain, which is common to VERL and the egg envelopes of vertebrates. Here, we use additional expressed sequence tag sequencing and shotgun proteomics to characterize this family of proteins in the abalone egg VE. We expand 3-fold the number of known ZP domain proteins present within the VE (now 30 in total) and identify a paralog of VERL (vitelline envelope zona pellucida domain protein [VEZP] 14) that contains a putative lysin-binding motif. We find that, like VERL, the divergence of VEZP14 among abalone species is driven by positive selection on the lysin-binding motif alone and that these paralogous egg VE proteins bind a similar set of sperm proteins including a rapidly evolving 18-kDa paralog of lysin, which may mediate sperm–egg fusion. This work identifies an egg coat paralog of VERL under positive selection and the candidate sperm proteins with which it may interact during abalone fertilization. PMID:19767347

Impact of post-rigor high pressure processing on the physicochemical and microbial shelf-life of cultured red abalone (Haliotis rufescens).

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Hughes, Brianna H; Perkins, L Brian; Yang, Tom C; Skonberg, Denise I

2016-03-01

High pressure processing (HPP) of post-rigor abalone at 300MPa for 10min extended the refrigerated shelf-life to four times that of unprocessed controls. Shucked abalone meats were processed at 100 or 300MPa for 5 or 10min, and stored at 2°C for 35days. Treatments were analyzed for aerobic plate count (APC), total volatile base nitrogen (TVBN), K-value, biogenic amines, color, and texture. APC did not exceed 10(6) and TVBN levels remained below 35mg/100g for 35days for the 300MPa treatments. No biogenic amines were detected in the 300MPa treatments, but putrescine and cadaverine were detected in the control and 100MPa treatments. Color and texture were not affected by HPP or storage time. These results indicate that post-rigor processing at 300MPa for 10min can significantly increase refrigerated shelf-life of abalone without affecting chemical or physical quality characteristics important to consumers. Copyright © 2015 Elsevier Ltd. All rights reserved.

Immune priming and portal of entry effectors improve response to vibrio infection in a resistant population of the European abalone.

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Dubief, Bruno; Nunes, Flavia L D; Basuyaux, Olivier; Paillard, Christine

2017-01-01

Since 1997, populations of the European abalone Haliotis tuberculata suffer mass mortalities attributed to the bacterium Vibrio harveyi. These mortalities occur at the spawning season, when the abalone immune system is depressed, and when temperatures exceed 17 °C, leading to favorable conditions for V. harveyi proliferation. In order to identify mechanisms of disease resistance, experimental successive infections were carried out on two geographically distinct Brittany populations: one that has suffered recurrent mortalities (Saint-Malo) and one that has not been impacted by the disease (Molène). Furthermore, abalone surviving these two successive bacterial challenges and uninfected abalone were used for several post-infection analyses. The Saint-Malo population was found to be resistant to V. harveyi infection, with a survival rate of 95% compared to 51% for Molène. While in vitro quantification of phagocytosis by flow cytometry showed strong inhibition following the first infection, no inhibition of phagocytosis was observed following the second infection for Saint-Malo, suggesting an immune priming effect. Moreover, assays of phagocytosis of GFP-labelled V. harveyi performed two months post-infection show an inhibition of phagocytosis by extracellular products of V. harveyi for uninfected abalone, while no effect was observed for previously infected abalone from Saint-Malo, suggesting that the effects of immune priming may last upwards of two months. Detection of V. harveyi by qPCR showed that a significantly greater number of abalone from the susceptible population were positive for V. harveyi in the gills, indicating that portal of entry effectors may play a role in resistance to the disease. Collectively, these results suggest a potential synergistic effect of gills and hemolymph in the resistance of H. tuberculata against V. harveyi with an important involvement of the gills, the portal of entry of the bacteria. Copyright © 2016 Elsevier Ltd

The role of organic intertile layer in abalone nacre

International Nuclear Information System (INIS)

Meyers, M.A.; Lim, C.T.; Li, A.; Hairul Nizam, B.R.; Tan, E.P.S.; Seki, Y.; McKittrick, J.

2009-01-01

Characterization of the growth surfaces removed from red and green abalone (Haliotis) shells shows a terraced cone mode of mineralization in which the organic layer is deposited periodically and regulates the formation of tiles with ∼ 500 nm thickness. The details of the mineral and organic layer surface are revealed by atomic force microscopy; the surface roughness and the thickness of the tiles in the terraces and organic intertile layer were measurement. Nanoindentation experiments at the top of the terraced cones confirm a hardness of the same order as that of completely mineralized surfaces. Indentation of the organic layer provides a force-deflection curve that can be expressed as tension on a centrally-loaded membrane. The results show that the dry organic layer is very stiff and deforms inelastically or cracks under the indenter, whereas in the fully hydrated state it shows a low modulus and strength and great extensibility. This strongly suggests that this organic interlayer acquires considerable strength and stiffness as a result of the drying process, which is consistent with a T g of approximately 200 deg. C for chitin. The chitin network that forms the structural component of the intertile layer is revealed and the orientation and spacing are measured. Terraced cones broken under the force of a flexing and shrinking organic layer enable the estimation of the tensile strength of the abalone when loaded through the fracture of the mineral bridges. Calculations show consistency with earlier tensile strength measurements of < 10 MPa.

Desarrollo del ensilado del alga Gracilaria chilensis para la alimentación del abalón rojo Haliotis rufescens

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Alfonso Mardones

2015-05-01

Full Text Available En Chile, el principal insumo usado como alimento para abalones son las algas Gracilaria chilensis y Macrocystis pyrifera. Estas algas experimentan una notable baja de disponibilidad en otoño e invierno, lo cual trae consigo un aumento considerable de los precios, al tener que depender del abastecimiento desde áreas cada vez más alejadas de los centros de cultivo de abalones y, eventualmente, generando impactos ecológicos indirectos en sus poblaciones. El objetivo fue elaborar y evaluar un ensilado del alga G. chilensis para la alimentación de abalón rojo (Haliotis rufescens, determinando la cantidad de lixiviados generados durante el proceso, el cambio en la composición proximal del alga, la preferencia y consumo del abalón rojo de ensilado de G. chilensis. Se logró un producto ensilado de buenas características físicas, químicas y de conservación, así como una buena aceptación por parte del abalón.

Nonsynonymous substitution in abalone sperm fertilization genes exceeds substitution in introns and mitochondrial DNA

Science.gov (United States)

Metz, Edward C.; Robles-Sikisaka, Refugio; Vacquier, Victor D.

1998-01-01

Strong positive Darwinian selection acts on two sperm fertilization proteins, lysin and 18-kDa protein, from abalone (Haliotis). To understand the phylogenetic context for this dramatic molecular evolution, we obtained sequences of mitochondrial cytochrome c oxidase subunit I (mtCOI), and genomic sequences of lysin, 18-kDa, and a G protein subunit. Based on mtDNA differentiation, four north Pacific abalone species diverged within the past 2 million years (Myr), and remaining north Pacific species diverged over a period of 4–20 Myr. Between-species nonsynonymous differences in lysin and 18-kDa exons exceed nucleotide differences in introns by 3.5- to 24-fold. Remarkably, in some comparisons nonsynonymous substitutions in lysin and 18-kDa genes exceed synonymous substitutions in mtCOI. Lysin and 18-kDa intron/exon segments were sequenced from multiple red abalone individuals collected over a 1,200-km range. Only two nucleotide changes and two sites of slippage variation were detected in a total of >29,000 nucleotides surveyed. However, polymorphism in mtCOI and a G protein intron was found in this species. This finding suggests that positive selection swept one lysin allele and one 18-kDa allele to fixation. Similarities between mtCOI and lysin gene trees indicate that rapid adaptive evolution of lysin has occurred consistently through the history of the group. Comparisons with mtCOI molecular clock calibrations suggest that nonsynonymous substitutions accumulate 2–50 times faster in lysin and 18-kDa genes than in rapidly evolving mammalian genes. PMID:9724763

Preliminary genetic linkage map of the abalone Haliotis diversicolor Reeve

Science.gov (United States)

Shi, Yaohua; Guo, Ximing; Gu, Zhifeng; Wang, Aimin; Wang, Yan

2010-05-01

Haliotis diversicolor Reeve is one of the most important mollusks cultured in South China. Preliminary genetic linkage maps were constructed with amplified fragment length polymorphism (AFLP) markers. A total of 2 596 AFLP markers were obtained from 28 primer combinations in two parents and 78 offsprings. Among them, 412 markers (15.9%) were polymorphic and segregated in the mapping family. Chi-square tests showed that 151 (84.4%) markers segregated according to the expected 1:1 Mendelian ratio ( P<0.05) in the female parent, and 200 (85.8%) in the male parent. For the female map, 179 markers were used for linkage analysis and 90 markers were assigned to 17 linkage groups with an average interval length of 25.7 cm. For the male map, 233 markers were used and 94 were mapped into 18 linkage groups, with an average interval of 25.0 cm. The estimated genome length was 2 773.0 cm for the female and 2 817.1 cm for the male map. The observed length of the linkage map was 1 875.2 cm and 1 896.5 cm for the female and male maps, respectively. When doublets were considered, the map length increased to 2 152.8 cm for the female and 2 032.7 cm for the male map, corresponding to genome coverage of 77.6% and 72.2%, respectively.

Comparison of the digestibility of abalone (Haliotis discus hannai) produced by four different processing treatments%四种加工方式对皱纹盘鲍制品消化特性的影响

Institute of Scientific and Technical Information of China (English)

万楚君; 游银川; 翁凌; 张凌晶; 刘光明; 曹敏杰

2017-01-01

为了探讨不同加工方式对皱纹盘鲍制品消化特性的影响,分析了生鲜、煮制、罐制和干制4种方式对鲍鱼肌肉蛋白在消化酶作用下的分解情况.利用模拟胃肠液消化及SDS-PAGE比较分析不同加工方式对鲍鱼肌肉消化特性的影响,并通过扫描电镜观察4种加工方式下鲍鱼肌肉组织微观结构的差异.结果显示,与生鲜鲍鱼相比,经煮制的鲍鱼较易被消化,罐制加工产品最易被消化,而干制鲍鱼最难被消化.不同加工方式对鲍鱼肌肉的组织结构有较大影响.进一步对不同皱纹盘鲍制品模拟胃肠液消化终产物的生物活性进行研究,发现它们对血管紧张素转换酶(ACE)的抑制活性(IC50)依次为罐制(464.2μg/mL)<干制(665.4μg/mL)<煮制(775.7μg/mL)<生鲜(803.9μg/mL).研究表明,不同加工方式对鲍鱼制品在机体内的消化特性及产物对ACE抑制活性存在差异,为优化鲍鱼制品生产加工提供了一定的参考.%In order to know the effect of different processing methods on protein digestion of abalone (Haliotis discus hannai), the effects of four processing methods including raw, boiling, canning, and drying on the digestibility of abalone muscular proteins were investigated. Simulated gastric fluid (SGF) as well as simulated intestinal fluid (SIF) was used to study the effects ofin vitro digestion. The products were evaluated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Scanning electronic microscopy (SEM) was used to observe the differences in the fiber of the four products. The results showed that the digestibility of proteins in canned abalone was the highest among the four processing methods. Proteins from dried abalone were most resistant to digestion both in SGF and SIF. The four processing methods revealed different fiber structures under SEM. Furthermore, the angiotensin-I converting enzyme (ACE) inhibitory activity of the digested products exhibited the

The role of organic intertile layer in abalone nacre

Energy Technology Data Exchange (ETDEWEB)

Meyers, M.A., E-mail: mameyers@ucsd.edu [University of California, San Diego, La Jolla, California (United States); Lim, C.T.; Li, A.; Hairul Nizam, B.R.; Tan, E.P.S. [National University of Singapore, Singapore (Singapore); Seki, Y.; McKittrick, J. [University of California, San Diego, La Jolla, California (United States)

2009-10-15

Characterization of the growth surfaces removed from red and green abalone (Haliotis) shells shows a terraced cone mode of mineralization in which the organic layer is deposited periodically and regulates the formation of tiles with {approx} 500 nm thickness. The details of the mineral and organic layer surface are revealed by atomic force microscopy; the surface roughness and the thickness of the tiles in the terraces and organic intertile layer were measurement. Nanoindentation experiments at the top of the terraced cones confirm a hardness of the same order as that of completely mineralized surfaces. Indentation of the organic layer provides a force-deflection curve that can be expressed as tension on a centrally-loaded membrane. The results show that the dry organic layer is very stiff and deforms inelastically or cracks under the indenter, whereas in the fully hydrated state it shows a low modulus and strength and great extensibility. This strongly suggests that this organic interlayer acquires considerable strength and stiffness as a result of the drying process, which is consistent with a T{sub g} of approximately 200 deg. C for chitin. The chitin network that forms the structural component of the intertile layer is revealed and the orientation and spacing are measured. Terraced cones broken under the force of a flexing and shrinking organic layer enable the estimation of the tensile strength of the abalone when loaded through the fracture of the mineral bridges. Calculations show consistency with earlier tensile strength measurements of < 10 MPa.

Hybridization improved bacteria resistance in abalone: Evidence from physiological and molecular responses.

Science.gov (United States)

Liang, Shuang; Luo, Xuan; You, Weiwei; Ke, Caihuan

2018-01-01

Hybridization is an effective way of improving germplasm in abalone, as it often generates benign traits in the hybrids. The hybrids of Haliotis discus hannai and H. gigantea have shown heterosis in terms of disease resistance than one or both parental species. In the present study, to elucidate the physiological and molecular mechanism of this heterosis, we analyzed the dynamic changes of several immune indexes including survival rate, total circulating haemocyte count (THC), phagocytic activity, reactive oxygen species level (ROS) and phenoloxidase activity (PO) in two parental species, H. discus hannai (DD) and H. gigantea (GG), and their reciprocal hybrids H. discus hannai ♀ × H. gigantea ♂ (DG), H. gigantea ♀ × H. discus hannai ♂ (GD) challenged with a mixture of Vibrio harveyi, V. alginolyticus and V. parahaemolyticus (which have been demonstrated to be pathogenic to abalone). Besides, we cloned and analyzed three important immune genes: heat shock protein 70 (hsp70), ferritin and cold shock domain protein (csdp) in H. discus hannai and H. gigantea, then further investigated their mRNA level changes in the four abalone genotypes after bacterial challenge. Results showed that these physiological and molecular parameters were significantly induced by bacterial exposure, and their changing patterns were obviously different between the four genotypes: (1) Survival rates of the two hybrids were higher than both parental species after bacterial exposure; (2) DG had higher THC than the other three genotypes; (3) Phagocytosis responded slower in the hybrids than in the parental species; (4) DD's ROS level was lower than the other three genotypes at 48 h post infection; (5) Phenoloxidase activity was lower in DD during the infection compared to the other genotypes; (6) mRNA levels of hsp70 and csdp, were always lower in at least one parental species (DD) than in the hybrids after the bacterial exposure. Results from this study indicate that the hybrids

Splice variants of perlucin from Haliotis laevigata modulate the crystallisation of CaCO3.

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Tanja Dodenhof

Full Text Available Perlucin is one of the proteins of the organic matrix of nacre (mother of pearl playing an important role in biomineralisation. This nacreous layer can be predominately found in the mollusc lineages and is most intensively studied as a compound of the shell of the marine Australian abalone Haliotis laevigata. A more detailed analysis of Perlucin will elucidate some of the still unknown processes in the complex interplay of the organic/inorganic compounds involved in the formation of nacre as a very interesting composite material not only from a life science-based point of view. Within this study we discovered three unknown Perlucin splice variants of the Australian abalone H. laevigata. The amplified cDNAs vary from 562 to 815 base pairs and the resulting translation products differ predominantly in the absence or presence of a varying number of a 10 mer peptide C-terminal repeat. The splice variants could further be confirmed by matrix-assisted laser desorption ionisation time of flight mass spectrometry (MALDI-ToF MS analysis as endogenous Perlucin, purified from decalcified abalone shell. Interestingly, we observed that the different variants expressed as maltose-binding protein (MBP fusion proteins in E. coli showed strong differences in their influence on precipitating CaCO3 and that these differences might be due to a splice variant-specific formation of large protein aggregates influenced by the number of the 10 mer peptide repeats. Our results are evidence for a more complex situation with respect to Perlucin functional regulation by demonstrating that Perlucin splice variants modulate the crystallisation of calcium carbonate. The identification of differentially behaving Perlucin variants may open a completely new perspective for the field of nacre biomineralisation.

Abalone viral ganglioneuritis: establishment and use of an experimental immersion challenge system for the study of abalone herpes virus infections in Australian abalone.

Science.gov (United States)

Corbeil, Serge; McColl, Kenneth A; Williams, Lynette M; Mohammad, Ilhan; Hyatt, Alexander D; Crameri, Sandra G; Fegan, Mark; Crane, Mark St J

2012-05-01

In late 2005, acute mortalities occurred in abalone on farms located in Victoria, Australia. Disease was associated with infection by an abalone herpes virus (AbHV). Subsequently, starting in 2006, the disease (abalone viral ganglioneuritis; AVG) was discovered in wild abalone in Victorian open waters. Currently, it continues to spread, albeit at a slow rate, along the Victorian coast-line. Here, we report on experimental transmission trials that were carried out by immersion using water into which diseased abalone had shed infectious viral particles. At various time points following exposure, naïve abalone were assessed by an AbHV-specific real-time PCR and histological analyses including in situ hybridization (ISH). Results demonstrated that while exposed abalone began displaying clinical signs of the disease from 60 hours post exposure (hpe), they tested positive for the presence of viral DNA at 36 hpe. Of further interest, the AbHV DNA probe used in the ISH assay detected the virus as early as 48 hpe. Crown Copyright © 2012. Published by Elsevier B.V. All rights reserved.

Antimicrobial and Antitumor Activities of Novel Peptides Derived from the Lipopolysaccharide- and β-1,3-Glucan Binding Protein of the Pacific Abalone Haliotis discus hannai

Directory of Open Access Journals (Sweden)

Bo-Hye Nam

2016-12-01

Full Text Available Antimicrobial peptides are a pivotal component of the invertebrate innate immune system. In this study, we identified a lipopolysaccharide- and β-1,3-glucan-binding protein (LGBP gene from the pacific abalone Haliotis discus hannai (HDH, which is involved in the pattern recognition mechanism and plays avital role in the defense mechanism of invertebrates immune system. The HDH-LGBP cDNA consisted of a 1263-bp open reading frame (ORF encoding a polypeptide of 420 amino acids, with a 20-amino-acid signal sequence. The molecular mass of the protein portion was 45.5 kDa, and the predicted isoelectric point of the mature protein was 4.93. Characteristic potential polysaccharide binding motif, glucanase motif, and β-glucan recognition motif were identified in the LGBP of HDH. We used its polysaccharide-binding motif sequence to design two novel antimicrobial peptide analogs (HDH-LGBP-A1 and HDH-LGBP-A2. By substituting a positively charged amino acid and amidation at the C-terminus, the pI and net charge of the HDH-LGBP increased, and the proteins formed an α-helical structure. The HDH-LGBP analogs exhibited antibacterial and antifungal activity, with minimal effective concentrations ranging from 0.008 to 2.2 μg/mL. Additionally, both were toxic against human cervix (HeLa, lung (A549, and colon (HCT 116 carcinoma cell lines but not much on human umbilical vein cell (HUVEC. Fluorescence-activated cell sorter (FACS analysis showed that HDH-LGBP analogs disturb the cancer cell membrane and cause apoptotic cell death. These results suggest the use of HDH-LGBP analogs as multifunctional drugs.

The identification of growth lines in abalone shell using a nuclear microprobe

International Nuclear Information System (INIS)

Bettiol, A.A.; Yang, C.; Hawkes, G.P.; Jamieson, D.N.; Malmqvist, K.G.; Day, R.W.

1999-01-01

Ionoluminescence (IL) combined with particle induced X-ray emission (PIXE) imaging has been employed to identify intrinsic growth bands in the spire region, and extrinsic bands at the growth edge of Australian Black-lip abalone shell (Haliotis rubra). Previous studies using optical flood cathodoluminescence, scanning electron microscope cathodoluminescence (SEM-CL) and Raman spectroscopy on samples from the same population suggest that the visible luminescence is due to Mn 2+ activated calcium carbonate. In this study we confirm Mn 2+ as the activator in both the spire and growth edge regions of the shell. The sensitivity of ionoluminescence to the co-ordination environment of the Mn 2+ activators in the shell allows for the spatial identification of the calcium carbonate polymorph responsible for the growth lines observed optically. Furthermore the detection and mapping of trace elements such as Mn and Sr with the PIXE technique enables comparisons to be made between calcite and aragonite biomineralized in the wild and under laboratory conditions

The identification of growth lines in abalone shell using a nuclear microprobe

Energy Technology Data Exchange (ETDEWEB)

Bettiol, A.A.; Yang, C.; Hawkes, G.P.; Jamieson, D.N. E-mail: dnj@physics.unimelb.edu.au; Malmqvist, K.G.; Day, R.W

1999-09-02

Ionoluminescence (IL) combined with particle induced X-ray emission (PIXE) imaging has been employed to identify intrinsic growth bands in the spire region, and extrinsic bands at the growth edge of Australian Black-lip abalone shell (Haliotis rubra). Previous studies using optical flood cathodoluminescence, scanning electron microscope cathodoluminescence (SEM-CL) and Raman spectroscopy on samples from the same population suggest that the visible luminescence is due to Mn{sup 2+} activated calcium carbonate. In this study we confirm Mn{sup 2+} as the activator in both the spire and growth edge regions of the shell. The sensitivity of ionoluminescence to the co-ordination environment of the Mn{sup 2+} activators in the shell allows for the spatial identification of the calcium carbonate polymorph responsible for the growth lines observed optically. Furthermore the detection and mapping of trace elements such as Mn and Sr with the PIXE technique enables comparisons to be made between calcite and aragonite biomineralized in the wild and under laboratory conditions.

Responses of primary cultured haemocytes from the marine gastropod Haliotis tuberculata under 10-day exposure to cadmium chloride

Energy Technology Data Exchange (ETDEWEB)

Latire, Thomas; Le Pabic, Charles; Mottin, Elmina; Mottier, Antoine; Costil, Katherine; Koueta, Noussithe; Lebel, Jean-Marc [UMR 100 IFREMER ' Physiologie et Ecophysiologie des Mollusques Marins' - IFR 146 ICORE - IBFA - Universite de Caen Basse-Normandie, Campus 1, Science C, Esplanade de la Paix, 14032 Caen cedex (France); Serpentini, Antoine, E-mail: antoine.serpentini@unicaen.fr [UMR 100 IFREMER ' Physiologie et Ecophysiologie des Mollusques Marins' - IFR 146 ICORE - IBFA - Universite de Caen Basse-Normandie, Campus 1, Science C, Esplanade de la Paix, 14032 Caen cedex (France)

2012-03-15

Among metals, cadmium, a non-essential element, is an important pollutant that is released into aquatic environments. Due to its persistence and bioaccumulation, this metal has been shown to exert immunological effects on organisms. The objective of the present study was to investigate the in vitro effects of cadmium chloride using a haemocyte primary culture from the European abalone, Haliotis tuberculata. Most studies have maintained viable haemocytes in vitro for periods ranging from several hours to several days during acute exposures. Few investigations have reported the effects of metals using longer in vitro exposures, which are more realistic with regard to mimicking environmental conditions. In this study, we exposed abalone haemocytes to concentrations from 0.5 to 50,000 {mu}g L{sup -1} of CdCl{sub 2} for 10 days. The effects of cadmium chloride were reflected in a significant decrease in the number of viable cells and morphological modifications in a concentration-dependent manner beginning at a concentration of 500 {mu}g L{sup -1} as well as in some physiological processes, such as phagocytotic activity and the number of lysosome-positive cells. In contrast, phenoloxidase (PO) activity and reactive oxygen species (ROS) production were increased beginning at a concentration of 5 {mu}g L{sup -1}, which is consistent with environmental concentrations in polluted sites. For PO activity and ROS production, maximally 9-fold and 130% inductions, respectively, were recorded under the highest dose. These results thus indicate that cadmium chloride alters immune parameters of abalone haemocytes and that the long-term (10 days) primary culture system used here represents a suitable, sensitive in vitro model for assessing cytotoxic responses.

Responses of primary cultured haemocytes from the marine gastropod Haliotis tuberculata under 10-day exposure to cadmium chloride

International Nuclear Information System (INIS)

Latire, Thomas; Le Pabic, Charles; Mottin, Elmina; Mottier, Antoine; Costil, Katherine; Koueta, Noussithé; Lebel, Jean-Marc; Serpentini, Antoine

2012-01-01

Among metals, cadmium, a non-essential element, is an important pollutant that is released into aquatic environments. Due to its persistence and bioaccumulation, this metal has been shown to exert immunological effects on organisms. The objective of the present study was to investigate the in vitro effects of cadmium chloride using a haemocyte primary culture from the European abalone, Haliotis tuberculata. Most studies have maintained viable haemocytes in vitro for periods ranging from several hours to several days during acute exposures. Few investigations have reported the effects of metals using longer in vitro exposures, which are more realistic with regard to mimicking environmental conditions. In this study, we exposed abalone haemocytes to concentrations from 0.5 to 50,000 μg L −1 of CdCl 2 for 10 days. The effects of cadmium chloride were reflected in a significant decrease in the number of viable cells and morphological modifications in a concentration-dependent manner beginning at a concentration of 500 μg L −1 as well as in some physiological processes, such as phagocytotic activity and the number of lysosome-positive cells. In contrast, phenoloxidase (PO) activity and reactive oxygen species (ROS) production were increased beginning at a concentration of 5 μg L −1 , which is consistent with environmental concentrations in polluted sites. For PO activity and ROS production, maximally 9-fold and 130% inductions, respectively, were recorded under the highest dose. These results thus indicate that cadmium chloride alters immune parameters of abalone haemocytes and that the long-term (10 days) primary culture system used here represents a suitable, sensitive in vitro model for assessing cytotoxic responses.

Heat inactivation of a norovirus surrogate in cell culture lysate, abalone meat, and abalone viscera.

Science.gov (United States)

Park, Shin Young; Bae, San-Cheong; Ha, Sang-Do

2015-03-01

The current study examined the effects of temperature and heat treatment duration on murine norovirus-1 (MNV-1) from both viral cell culture lysate (7-8 log10 PFU) and experimentally contaminated abalone meat and viscera (5-6 log10 PFU) as a model of human norovirus (NoV). MNV-1 titers in cell culture lysate, abalone meat, and abalone viscera were gradually reduced to 1.93-4.55, 1.79-3.00, and 2.26-3.26 log10 PFU/ml, respectively, after treatment at 70 °C for 1-10 min. Treatment at 85 °C for 1-5 min gradually reduced MNV-1 titers in abalone meat to 2.71-4.15 log10 PFU/ml. MNV-1 titers in abalone viscera were gradually reduced to 2.91-3.46 log10 PFU/ml after treatment at 85 °C for 1-3 min. No significant difference (P > 0.05) was found in MNV-1 titers in the abalone meat and viscera among treatment groups (70 °C for 5 min, 70 °C for 3 min, and 85 °C for 1 min). Complete inactivation of MNV-1 in cell culture lysate was determined at 85 °C for ≥1 min and 100 °C for ≥0.5 min. Complete inactivation of MNV-1 in abalone was determined at 100 °C for ≥0.5 min for meat, and 85 °C for 5 min and 100 °C for ≥0.5 min for viscera. At treatments at 70 °C, the Td-values (3 log reduction time) were significantly lower (P abalone meat (6.07) and viscera (10.73). Td = 3 values were not significantly different (P > 0.05) between abalone meat (1.78) and abalone viscera (1.33) at treatments at 85 °C. This study suggests that 100 °C for ≥0.5 min could potentially be used to inactivate NoV in molluscan shellfishes, including viscera.

Population structure and growth of polydorid polychaetes that infest ...

African Journals Online (AJOL)

Polydorid polychaetes can infest cultured abalone thereby reducing productivity. In order to effectively control these pests, their reproductive biology must be understood. The population dynamics and reproduction of polydorids infesting abalone Haliotis midae from two farms in South Africa is described using a ...

Exploring basic biochemical constituents in the body tissues of ...

African Journals Online (AJOL)

Feeding regime did not influence susceptibility to mass loss during export. Animal age influenced the biochemical composition and export performance of abalone. Keywords: abalone; aquaculture; feeds; Haliotis midae; live export; mass loss; tissue biochemical constituents. African Journal of Marine Science 2010, 32(1): ...

Leucopenia associated with abalone viral ganglioneuritis.

Science.gov (United States)

Hooper, C; Slocombe, R; Day, R; Crawford, S

2012-01-01

To compare microscopic lesion severity with circulating total haemocyte counts (THC) in abalone affected by abalone viral ganglioneuritis (AVG). A herpes-like virus led to severe mortality in a number of Australian abalone farms in 2006. The infection was associated with severe necrotising ganglioneuritis. The microscopic lesions were well demarcated, affecting the neural tissue almost exclusively and were characterised by necrosis and increased cellularity in affected ganglia and nerves. On two farms, the presence or absence of typical AVG pathology was compared with THC. Those abalone with microscopic lesions of AVG had significantly lower haemocyte counts. The mean THC in abalone with no evidence of AVG from both farms was 4.6 × 10(6)/mL (±0.3 SE). The THC in AVG-affected abalone in farm 1 was 2.8 × 10(6)/mL (±0.5 SE) and farm 2 was 0.98 × 10(6)/mL (±0.4 SE). Severe AVG is associated with leucopenia in affected abalone. © 2012 The Authors. Australian Veterinary Journal © 2012 Australian Veterinary Association.

[Identification of irradiated abalone by ESR spectroscopy].

Science.gov (United States)

Song, Yeping; Wang, Chuanxian; Yang, Zhenyu; Zhong, Weike; Geng, Jinpei; Lu, Di; Ding, Zhuoping

2012-05-01

To establish an analytical method for the detection and identification of irradiated abalone by electron spin resonance spectroscopy. Electron spin resonance (ESR) was used to study the spectral characteristics of abalone and the characteristic peak for quantitation. There were obvious different ESR spectra between unirradiated and irradiated abalone. The g factor for unirradiated abalone was 2.0055-2.0060, the g1 and g2 factor for irradiated abalone were (2.0027 +/- 0.0001) and (1.9994 +/- 0.0001), respectively. The ESR signal intensity of characteristic peak was positively correlated with absorbed dose in the range of 0.5 - 10 kGy, left peak was the characteristic peak for quantitation and the detection limit was abalone. ESR spectroscopy is an effective method to determine whether the abalone being irradiated or not.

Gradual Ordering in Red Abalone Nacre

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Gilbert, P. U. P. A.; Metzler, Rebecca A.; Zhou, Dong; Scholl, Andreas; Doran, Andrew; Young, Anthony; Kunz, Martin; Tamura, Nobumichi; Coppersmith, Susan N.

2008-09-03

Red abalone (Haliotis rufescens) nacre is a layered composite biomineral that contains crystalline aragonite tablets confined by organic layers. Nacre is intensely studied because its biologically controlled microarchitecture gives rise to remarkable strength and toughness, but the mechanisms leading to its formation are not well understood. Here we present synchrotron spectromicroscopy experiments revealing that stacks of aragonite tablet crystals in nacre are misoriented with respect to each other. Quantitative measurements of crystal orientation, tablet size, and tablet stacking direction show that orientational ordering occurs not abruptly but gradually over a distance of 50 {micro}m. Several lines of evidence indicate that different crystal orientations imply different tablet growth rates during nacre formation. A theoretical model based on kinetic and gradual selection of the fastest growth rates produces results in qualitative and quantitative agreement with the experimental data and therefore demonstrates that ordering in nacre is a result of crystal growth kinetics and competition either in addition or to the exclusion of templation by acidic proteins as previously assumed. As in other natural evolving kinetic systems, selection of the fastest-growing stacks of tablets occurs gradually in space and time. These results suggest that the self-ordering of the mineral phase, which may occur completely independently of biological or organic-molecule control, is fundamental in nacre formation.

Gradual Ordering in Red Abalone Nacre

International Nuclear Information System (INIS)

Gilbert, P.U.P.A.; Metzler, Rebecca A.; Zhou, Dong; Scholl, Andreas; Doran, Andrew; Young, Anthony; Kunz, Martin; Tamura, Nobumichi; Coppersmith, Susan N.

2008-01-01

Red abalone (Haliotis rufescens) nacre is a layered composite biomineral that contains crystalline aragonite tablets confined by organic layers. Nacre is intensely studied because its biologically controlled microarchitecture gives rise to remarkable strength and toughness, but the mechanisms leading to its formation are not well understood. Here we present synchrotron spectromicroscopy experiments revealing that stacks of aragonite tablet crystals in nacre are misoriented with respect to each other. Quantitative measurements of crystal orientation, tablet size, and tablet stacking direction show that orientational ordering occurs not abruptly but gradually over a distance of 50 (micro)m. Several lines of evidence indicate that different crystal orientations imply different tablet growth rates during nacre formation. A theoretical model based on kinetic and gradual selection of the fastest growth rates produces results in qualitative and quantitative agreement with the experimental data and therefore demonstrates that ordering in nacre is a result of crystal growth kinetics and competition either in addition or to the exclusion of templation by acidic proteins as previously assumed. As in other natural evolving kinetic systems, selection of the fastest-growing stacks of tablets occurs gradually in space and time. These results suggest that the self-ordering of the mineral phase, which may occur completely independently of biological or organic-molecule control, is fundamental in nacre formation

Growth of nacre in abalone: Seasonal and feeding effects

International Nuclear Information System (INIS)

Lopez, M.I.; Chen, P.Y.; McKittrick, J.; Meyers, M.A.

2011-01-01

The processes of aggregation of mineral and organic materials to the growing surfaces in red abalone (Haliotis rufescens) are analyzed. The flat pearl implantation method is used to observe the transient stages of calcium carbonate deposition, the structure of the organic interlayer, and the steady-state growth of aragonite tiles. The morphology of the organic interlayer is characterized by scanning electron microscopy. These results enable a realistic depiction of the formation of the terraced cones that comprise the principal biomineralization mechanism in this gastropod. In all cases, the growth initiated through spherulites, followed by tile formation. The transient stage with spherulitic formation was shorter at higher temperature; this is indicative of a greater activity of the animal at 21 deg. C. The growth rate in a normally fed gastropod was found to be higher compared with one provided with limited food. The effect of water temperature (seasonal) was also established, with growth proceeding faster in the summer (T ∼ 21 deg. C) than in winter (15 deg. C). The structures of the organic interlayer and of the epithelium are revealed by scanning electron microscopy.

Growth of nacre in abalone: Seasonal and feeding effects

Energy Technology Data Exchange (ETDEWEB)

Lopez, M.I., E-mail: mil032@ucsd.edu; Chen, P.Y.; McKittrick, J.; Meyers, M.A.

2011-03-12

The processes of aggregation of mineral and organic materials to the growing surfaces in red abalone (Haliotis rufescens) are analyzed. The flat pearl implantation method is used to observe the transient stages of calcium carbonate deposition, the structure of the organic interlayer, and the steady-state growth of aragonite tiles. The morphology of the organic interlayer is characterized by scanning electron microscopy. These results enable a realistic depiction of the formation of the terraced cones that comprise the principal biomineralization mechanism in this gastropod. In all cases, the growth initiated through spherulites, followed by tile formation. The transient stage with spherulitic formation was shorter at higher temperature; this is indicative of a greater activity of the animal at 21 deg. C. The growth rate in a normally fed gastropod was found to be higher compared with one provided with limited food. The effect of water temperature (seasonal) was also established, with growth proceeding faster in the summer (T {approx} 21 deg. C) than in winter (15 deg. C). The structures of the organic interlayer and of the epithelium are revealed by scanning electron microscopy.

Anti-Inflammatory Effect of By-Products from Haliotis discus hannai in RAW 264.7 Cells

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Ho-Seok Rho

2015-01-01

Full Text Available Several reports promoted the potential of shellfish due to their ability to act as antioxidant, anti-inflammatory, and antimicrobial agents. Pacific abalone, Haliotis discus hannai viscera is, reported to possess bioactivities such as antioxidative stress and anti-inflammatory. In this study, anti-inflammatory potential of mucus-secreting glands from shell-shucking waste of H. discus hannai was evaluated using RAW 264.7 mouse macrophage cell model. Results indicated that presence of H. discus hannai mucosubstance by-products (AM significantly lowered the nitric oxide (NO production along the expressional suppression of inflammatory mediators such as cytokines TNF-α, IL-1β, and IL-6 and enzymes iNOS and COX-2. Also, AM was shown to increase expression of anti-inflammatory response mediator HO-1. Presence of AM also scavenged the free radicals in vitro. In conclusion, by-products of H. discus hannai are suggested to possess notable anti-inflammatory potential which promotes the possibility of utilization as functional food ingredient.

Exploring Spatiotemporal Trends in Commercial Fishing Effort of an Abalone Fishing Zone: A GIS-Based Hotspot Model

Science.gov (United States)

Jalali, M. Ali; Ierodiaconou, Daniel; Gorfine, Harry; Monk, Jacquomo; Rattray, Alex

2015-01-01

Assessing patterns of fisheries activity at a scale related to resource exploitation has received particular attention in recent times. However, acquiring data about the distribution and spatiotemporal allocation of catch and fishing effort in small scale benthic fisheries remains challenging. Here, we used GIS-based spatio-statistical models to investigate the footprint of commercial diving events on blacklip abalone (Haliotis rubra) stocks along the south-west coast of Victoria, Australia from 2008 to 2011. Using abalone catch data matched with GPS location we found catch per unit of fishing effort (CPUE) was not uniformly spatially and temporally distributed across the study area. Spatial autocorrelation and hotspot analysis revealed significant spatiotemporal clusters of CPUE (with distance thresholds of 100’s of meters) among years, indicating the presence of CPUE hotspots focused on specific reefs. Cumulative hotspot maps indicated that certain reef complexes were consistently targeted across years but with varying intensity, however often a relatively small proportion of the full reef extent was targeted. Integrating CPUE with remotely-sensed light detection and ranging (LiDAR) derived bathymetry data using generalized additive mixed model corroborated that fishing pressure primarily coincided with shallow, rugose and complex components of reef structures. This study demonstrates that a geospatial approach is efficient in detecting patterns and trends in commercial fishing effort and its association with seafloor characteristics. PMID:25992800

Exploring Spatiotemporal Trends in Commercial Fishing Effort of an Abalone Fishing Zone: A GIS-Based Hotspot Model.

Directory of Open Access Journals (Sweden)

M Ali Jalali

Full Text Available Assessing patterns of fisheries activity at a scale related to resource exploitation has received particular attention in recent times. However, acquiring data about the distribution and spatiotemporal allocation of catch and fishing effort in small scale benthic fisheries remains challenging. Here, we used GIS-based spatio-statistical models to investigate the footprint of commercial diving events on blacklip abalone (Haliotis rubra stocks along the south-west coast of Victoria, Australia from 2008 to 2011. Using abalone catch data matched with GPS location we found catch per unit of fishing effort (CPUE was not uniformly spatially and temporally distributed across the study area. Spatial autocorrelation and hotspot analysis revealed significant spatiotemporal clusters of CPUE (with distance thresholds of 100's of meters among years, indicating the presence of CPUE hotspots focused on specific reefs. Cumulative hotspot maps indicated that certain reef complexes were consistently targeted across years but with varying intensity, however often a relatively small proportion of the full reef extent was targeted. Integrating CPUE with remotely-sensed light detection and ranging (LiDAR derived bathymetry data using generalized additive mixed model corroborated that fishing pressure primarily coincided with shallow, rugose and complex components of reef structures. This study demonstrates that a geospatial approach is efficient in detecting patterns and trends in commercial fishing effort and its association with seafloor characteristics.

The effects of intermittent exposure to low-pH and low-oxygen conditions on survival and growth of juvenile red abalone

Science.gov (United States)

Kim, T. W.; Barry, J. P.; Micheli, F.

2013-11-01

Exposure of nearshore animals to hypoxic, low-pH waters upwelled from below the continental shelf and advected near the coast may be stressful to marine organisms and lead to impaired physiological performance. We mimicked upwelling conditions in the laboratory and tested the effect of fluctuating exposure to water with low-pH and/or low-oxygen levels on the mortality and growth of juvenile red abalone (Haliotis rufescens, shell length 5-10 mm). Mortality rates of juvenile abalone exposed to low-pH (7.5, total scale) and low-O2 (40% saturation, mg L-1) conditions for periods of 3 to 6 h every 3-5 days over 2 weeks did not differ from those exposed to control conditions (O2: 100% saturation, 12 mg L-1; pH 8.0). However, when exposure was extended to 24 h, twice over a 15-day period, juveniles experienced 5-20% higher mortality in the low-oxygen treatments compared to control conditions. Growth rates were reduced significantly when juveniles were exposed to low-oxygen and low-pH treatments. Furthermore, individual variation of growth rate increased when juveniles were exposed simultaneously to low-pH and low-O2 conditions. These results indicate that prolonged exposure to low-oxygen levels is detrimental for the survival of red abalone, whereas pH is a crucial factor for their growth. However, the high individual variation in growth rate under low levels of both pH and oxygen suggests that cryptic phenotypic plasticity may promote resistance to prolonged upwelling conditions by a portion of the population.

Anticoagulant Activity and Structural Characterization of Polysaccharide from Abalone (Haliotis discus hannai Ino Gonad

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Jun Zhao

2016-06-01

Full Text Available In this study, we aimed at characterizing the structure and the anticoagulant activity of a polysaccharide fraction (AGP33 isolated from the gonads of Haliotis discus hannai Ino. AGP33 was extracted by enzymatic hydrolysis and purified by ion-exchange and gel-filtration chromatography. The backbone fraction of AGP33 (BAGP33, which appeared to contain of mannose, glucose and galactose, was prepared by partial acid hydrolysis. According to methylation and nuclear magnetic resonance (NMR spectroscopy, the backbone of AGP33 was identified as mainly consisting of 1→3-linked, 1→4-linked, and 1→6-linked monosaccharides. AGP33 is a sulfated polysaccharide with sulfates occur at 3-O- and 4-O-positions. It prolonged thromboplastin time (APTT, thrombin time (TT and prothrombin time (PT compared to a saline control solution in a dosage-dependent manner. AGP33 exhibited an extension (p < 0.01 of APTT compared to the saline group at concentrations higher than 5 μg/mL. AGP33 exhibited higher anticoagulant activity than its desulfated product (AGP33-des and BAGP33. The results showed that polysaccharide with higher molecular weight and sulfate content demonstrated greater anticoagulant activity.

Reprint of: Growth of nacre in abalone: Seasonal and feeding effects

Energy Technology Data Exchange (ETDEWEB)

Lopez, M.I., E-mail: mil032@ucsd.edu; Chen, P.Y.; McKittrick, J.; Meyers, M.A.

2011-05-10

The processes of aggregation of mineral and organic materials to the growing surfaces in red abalone (Haliotis rufescens) are analyzed. The flat pearl implantation method is used to observe the transient stages of calcium carbonate deposition, the structure of the organic interlayer, and the steady-state growth of aragonite tiles. The morphology of the organic interlayer is characterized by scanning electron microscopy. These results enable a realistic depiction of the formation of the terraced cones that comprise the principal biomineralization mechanism in this gastropod. In all cases, the growth initiated through spherulites, followed by tile formation. The transient stage with spherulitic formation was shorter at higher temperature; this is indicative of a greater activity of the animal at 21 deg. C. The growth rate in a normally fed gastropod was found to be higher compared with one provided with limited food. The effect of water temperature (seasonal) was also established, with growth proceeding faster in the summer (T {approx} 21 deg. C) than in winter (15 deg. C). The structures of the organic interlayer and of the epithelium are revealed by scanning electron microscopy.

Reprint of: Growth of nacre in abalone: Seasonal and feeding effects

International Nuclear Information System (INIS)

Lopez, M.I.; Chen, P.Y.; McKittrick, J.; Meyers, M.A.

2011-01-01

The processes of aggregation of mineral and organic materials to the growing surfaces in red abalone (Haliotis rufescens) are analyzed. The flat pearl implantation method is used to observe the transient stages of calcium carbonate deposition, the structure of the organic interlayer, and the steady-state growth of aragonite tiles. The morphology of the organic interlayer is characterized by scanning electron microscopy. These results enable a realistic depiction of the formation of the terraced cones that comprise the principal biomineralization mechanism in this gastropod. In all cases, the growth initiated through spherulites, followed by tile formation. The transient stage with spherulitic formation was shorter at higher temperature; this is indicative of a greater activity of the animal at 21 deg. C. The growth rate in a normally fed gastropod was found to be higher compared with one provided with limited food. The effect of water temperature (seasonal) was also established, with growth proceeding faster in the summer (T ∼ 21 deg. C) than in winter (15 deg. C). The structures of the organic interlayer and of the epithelium are revealed by scanning electron microscopy.

The effects of intermittent exposure to low pH and oxygen conditions on survival and growth of juvenile red abalone

Science.gov (United States)

Kim, T. W.; Barry, J. P.; Micheli, F.

2013-02-01

Exposure of nearshore animals to hypoxic, low pH waters upwelled from below the continental shelf and advected near the coast may be stressful to marine organisms and lead to impaired physiological performance. We mimicked upwelling conditions in the laboratory and tested the effect of fluctuating exposure to water with low pH and/or low oxygen levels on the mortality and growth of juvenile red abalone (Haliotis rufescens, shell length 5-10 mm). Mortality rates of juvenile abalone exposed to low pH (7.5, total scale) and low O2 (40% saturation, 5 mg L-1) conditions for periods of 3 to 6 h every 3-5 days over 2 weeks did not differ from those exposed to control conditions (O2: 100% saturation, 12 mg L-1; pH 8.0). However, when exposure was extended to 24 h repeated twice over a 15 day period, juveniles experienced higher mortality in the low oxygen treatments compared to control conditions, regardless of pH levels (pH 7.5 vs. 8.0). Growth rates were reduced significantly when juveniles were exposed to low pH or low oxygen treatments and the growth was lowest when low pH exposure was combined with low O2. Furthermore, individual variation of growth rate increased when they were exposed to low pH and low O2 conditions. These results indicate that prolonged exposure to low oxygen levels is detrimental for the survival of red abalone, whereas both pH and oxygen is a crucial factor for their growth. However, given the higher individual variation in growth rate, they may have an ability to adapt to extended exposure to upwelling conditions.

Fishing diseased abalone to promote yield and conservation

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Ben-Horin, Tal; Lafferty, Kevin D.; Bidegain, Gorka; Lenihan, Hunter S.

2016-01-01

Past theoretical models suggest fishing disease-impacted stocks can reduce parasite transmission, but this is a good management strategy only when the exploitation required to reduce transmission does not overfish the stock. We applied this concept to a red abalone fishery so impacted by an infectious disease (withering syndrome) that stock densities plummeted and managers closed the fishery. In addition to the non-selective fishing strategy considered by past disease-fishing models, we modelled targeting (culling) infected individuals, which is plausible in red abalone because modern diagnostic tools can determine infection without harming landed abalone and the diagnostic cost is minor relative to the catch value. The non-selective abalone fishing required to eradicate parasites exceeded thresholds for abalone sustainability, but targeting infected abalone allowed the fishery to generate yield and reduce parasite prevalence while maintaining stock densities at or above the densities attainable if the population was closed to fishing. The effect was strong enough that stock and yield increased even when the catch was one-third uninfected abalone. These results could apply to other fisheries as the diagnostic costs decline relative to catch value.

Fishing diseased abalone to promote yield and conservation.

Science.gov (United States)

Ben-Horin, Tal; Lafferty, Kevin D; Bidegain, Gorka; Lenihan, Hunter S

2016-03-05

Past theoretical models suggest fishing disease-impacted stocks can reduce parasite transmission, but this is a good management strategy only when the exploitation required to reduce transmission does not overfish the stock. We applied this concept to a red abalone fishery so impacted by an infectious disease (withering syndrome) that stock densities plummeted and managers closed the fishery. In addition to the non-selective fishing strategy considered by past disease-fishing models, we modelled targeting (culling) infected individuals, which is plausible in red abalone because modern diagnostic tools can determine infection without harming landed abalone and the diagnostic cost is minor relative to the catch value. The non-selective abalone fishing required to eradicate parasites exceeded thresholds for abalone sustainability, but targeting infected abalone allowed the fishery to generate yield and reduce parasite prevalence while maintaining stock densities at or above the densities attainable if the population was closed to fishing. The effect was strong enough that stock and yield increased even when the catch was one-third uninfected abalone. These results could apply to other fisheries as the diagnostic costs decline relative to catch value. © 2016 The Author(s).

Overexploitation of Abalone at Libong Island, Trang Province, Southern Thailand

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Chanyut Sudtongkong

2012-09-01

Full Text Available Abalone is generally known as a fishery resource of high economic value. The wild abalone from Libong Island iswidely known for its potential as a cocktail-size and high-quality broodstock for hatcheries. The high market price andexternal demand have encouraged local fisherman to catch the wild abalone without proper management, resulting in a nearextinction crisis in the abalone population in this area. The present evaluation of abalone management at Libong Island,Trang Province, Thailand, was conducted using local user perceptions. Sixteen performance indicators included effectiveness indicators, equity indicators, and sustainable indicators. These were measured to determine whether the abalonemanagement activities had achieved the set objectives in terms of better conditions for abalone cultivation and sustainability.The results revealed that the abalone population has undergone degrading and decline due to lack of proper managementmeasures in this area. The findings suggest that practical management is needed for the abalone population at Libong Island.

Convective Drying of Osmo-Treated Abalone (Haliotis rufescens Slices: Diffusion, Modeling, and Quality Features

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Roberto Lemus-Mondaca

2018-01-01

Full Text Available The focus of this research was based on the application of an osmotic pretreatment (15% NaCl for drying abalone slices, and it evaluates the influence of hot-air drying temperature (40–80°C on the product quality. In addition, the mass transfer kinetics of salt and water was also studied. The optimal time of the osmotic treatment was established until reaching a pseudo equilibrium state of the water and salt content (290 min. The water effective diffusivity values during drying ranged from 3.76 to 4.75 × 10−9 m2/s for three selected temperatures (40, 60, and 80°C. In addition, experimental data were fitted by Weibull distribution model. The modified Weibull model provided good fitting of experimental data according to applied statistical tests. Regarding the evaluated quality parameters, the color of the surface showed a change more significant at high temperature (80°C, whereas the nonenzymatic browning and texture showed a decrease during drying process mainly due to changes in protein matrix and rehydration rates, respectively. In particular, working at 60°C resulted in dried samples with the highest quality parameters.

40 CFR 408.330 - Applicability; description of the abalone processing subcategory.

Science.gov (United States)

2010-07-01

... abalone processing subcategory. 408.330 Section 408.330 Protection of Environment ENVIRONMENTAL PROTECTION... CATEGORY Abalone Processing Subcategory § 408.330 Applicability; description of the abalone processing... abalone in the contiguous states. ...

Assessment of oxytetracycline baths as therapeutic treatment for the control of the agent of withering syndrome (WS) in red abalone (Haliotis rufescens).

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Winkler, Federico M; García, Ricardo; Valdivia, María Vicenta; Lohrmann, Karin B

2018-03-01

Withering Syndrome (WS) is a lethal disease that affects abalone species in both wild and farmed populations. This infection, caused by the rickettsial-like intracellular organism (RLO) Candidatus Xenohaliotis californiensis, can severely impair the normal development of affected animals, and ultimately, their survival. The most common line of action against the WS has been the use of antibiotics, specifically oxytetracycline (OTC), administered via intramuscular injection and per os via medicated feed. In the present study, we have assessed the effectiveness of OTC baths as therapeutic treatment for the control of the WS agent in H. rufescens. Clinical signs of infection were monitored for 11 months in treated juveniles, in addition to feed consumption rate, growth patterns and gonad development. Abalones were asymptomatic until the end of the experiment, when a small number of non-treated animals exhibited clinical signs of infection. Gonad maturity was not observed. OTC treated animals grew significantly less than their non-treated counterparts, being 4.3% shorter and 13.6% lighter at the end of the experiment. They also displayed negative allometry, i.e. for the same shell length, they were lighter than non-treated groups. Furthermore, the weight of muscle and soft tissues in OTC treated animals was lighter than in the other groups, while no differences were found in shell weight. The feed consumption rate was the same for all groups, thus the observed growth patterns cannot be attributed to a decreased feed intake. One possible explanation is that antibiotic treatment may have impacted gut microflora, thus preventing efficient nutrient digestion and absorption and, indirectly, reducing growth. Prevalence of RLOs causing WS (WS-RLO) and the variant form (RLOv), infected with a bacteriophague and non virulent, were significantly lower in the OTC-treated group than in the other groups. Similar results were observed for the mean intensity of RLOv, while for WS

Duplicate Abalone Egg Coat Proteins Bind Sperm Lysin Similarly, but Evolve Oppositely, Consistent with Molecular Mimicry at Fertilization

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Aagaard, Jan E.; Springer, Stevan A.; Soelberg, Scott D.; Swanson, Willie J.

2013-01-01

Sperm and egg proteins constitute a remarkable paradigm in evolutionary biology: despite their fundamental role in mediating fertilization (suggesting stasis), some of these molecules are among the most rapidly evolving ones known, and their divergence can lead to reproductive isolation. Because of strong selection to maintain function among interbreeding individuals, interacting fertilization proteins should also exhibit a strong signal of correlated divergence among closely related species. We use evidence of such molecular co-evolution to target biochemical studies of fertilization in North Pacific abalone (Haliotis spp.), a model system of reproductive protein evolution. We test the evolutionary rates (d N/d S) of abalone sperm lysin and two duplicated egg coat proteins (VERL and VEZP14), and find a signal of co-evolution specific to ZP-N, a putative sperm binding motif previously identified by homology modeling. Positively selected residues in VERL and VEZP14 occur on the same face of the structural model, suggesting a common mode of interaction with sperm lysin. We test this computational prediction biochemically, confirming that the ZP-N motif is sufficient to bind lysin and that the affinities of VERL and VEZP14 are comparable. However, we also find that on phylogenetic lineages where lysin and VERL evolve rapidly, VEZP14 evolves slowly, and vice versa. We describe a model of sexual conflict that can recreate this pattern of anti-correlated evolution by assuming that VEZP14 acts as a VERL mimic, reducing the intensity of sexual conflict and slowing the co-evolution of lysin and VERL. PMID:23408913

Duplicate abalone egg coat proteins bind sperm lysin similarly, but evolve oppositely, consistent with molecular mimicry at fertilization.

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Jan E Aagaard

Full Text Available Sperm and egg proteins constitute a remarkable paradigm in evolutionary biology: despite their fundamental role in mediating fertilization (suggesting stasis, some of these molecules are among the most rapidly evolving ones known, and their divergence can lead to reproductive isolation. Because of strong selection to maintain function among interbreeding individuals, interacting fertilization proteins should also exhibit a strong signal of correlated divergence among closely related species. We use evidence of such molecular co-evolution to target biochemical studies of fertilization in North Pacific abalone (Haliotis spp., a model system of reproductive protein evolution. We test the evolutionary rates (d(N/d(S of abalone sperm lysin and two duplicated egg coat proteins (VERL and VEZP14, and find a signal of co-evolution specific to ZP-N, a putative sperm binding motif previously identified by homology modeling. Positively selected residues in VERL and VEZP14 occur on the same face of the structural model, suggesting a common mode of interaction with sperm lysin. We test this computational prediction biochemically, confirming that the ZP-N motif is sufficient to bind lysin and that the affinities of VERL and VEZP14 are comparable. However, we also find that on phylogenetic lineages where lysin and VERL evolve rapidly, VEZP14 evolves slowly, and vice versa. We describe a model of sexual conflict that can recreate this pattern of anti-correlated evolution by assuming that VEZP14 acts as a VERL mimic, reducing the intensity of sexual conflict and slowing the co-evolution of lysin and VERL.

Abalone water-soluble matrix for self-healing biomineralization of tooth defects

Energy Technology Data Exchange (ETDEWEB)

Wen, Zhenliang [Institute of Biomedical and Pharmaceutical Technology, Fuzhou University, Fuzhou 350002 (China); Chen, Jingdi, E-mail: ibptcjd@fzu.edu.cn [Institute of Biomedical and Pharmaceutical Technology, Fuzhou University, Fuzhou 350002 (China); Wang, Hailiang [The Affiliated Stomatological Hospital, Fujian Medical University, Fuzhou 350002 (China); Zhong, Shengnan; Hu, Yimin; Wang, Zhili [Institute of Biomedical and Pharmaceutical Technology, Fuzhou University, Fuzhou 350002 (China); Zhang, Qiqing, E-mail: zhangqiq@126.com [Institute of Biomedical and Pharmaceutical Technology, Fuzhou University, Fuzhou 350002 (China); Institute of Biomedical Engineering, Chinese Academy of Medical Science & Peking Union Medical College, Tianjin 300192 (China)

2016-10-01

Enamel cannot heal by itself if damaged. Hydroxyapatite (HAP) is main component of human enamel. Formation of enamel-like materials for healing enamel defects remains a challenge. In this paper, we successfully isolated the abalone water-soluble matrix (AWSM) with 1.53 wt% the abalone water-soluble protein (AWSPro) and 2.04 wt% the abalone water-soluble polysaccharide (AWSPs) from abandoned abalone shell, and self-healing biomineralization of tooth defects was successfully achieved in vitro. Based on X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), hot field emission scanning electron microscopy (HFESEM) and energy dispersive spectrometer (EDS) analysis, the results showed that the AWSM can efficiently induce remineralization of HAP. The enamel-like HAP was successfully achieved onto etched enamel's surface due to the presence of the AWSM. Moreover, the remineralized effect of eroded enamel was growing with the increase of the AWSM. This study provides a solution to the resource waste and environmental pollution caused by abandoned abalone shell, and we provides a new method for self-healing remineralization of enamel defects by AWSM and develops a novel dental material for potential clinical dentistry application. - Graphical abstract: In this paper, we successfully isolated the abalone water-soluble matrix (AWSM) with 1.53 wt% abalone water-soluble protein (AWSPro) and 2.04 wt% abalone water-soluble polysaccharide (AWSPs) from abandoned abalone shell, and self-healing biomineralization of tooth defects was successfully achieved in vitro by self-organized. Display Omitted - Highlights: • Provides a solution to the resource waste and environmental pollution caused by abandoned abalone shell. • The abalone shell water-soluble matrix contains protein and polysaccharide. • The abalone water-soluble matrix can efficiently induce remineralization of HAP by self-organized. • Achieved self-healing biomineralization of tooth defects in

Abalone water-soluble matrix for self-healing biomineralization of tooth defects

International Nuclear Information System (INIS)

Wen, Zhenliang; Chen, Jingdi; Wang, Hailiang; Zhong, Shengnan; Hu, Yimin; Wang, Zhili; Zhang, Qiqing

2016-01-01

Enamel cannot heal by itself if damaged. Hydroxyapatite (HAP) is main component of human enamel. Formation of enamel-like materials for healing enamel defects remains a challenge. In this paper, we successfully isolated the abalone water-soluble matrix (AWSM) with 1.53 wt% the abalone water-soluble protein (AWSPro) and 2.04 wt% the abalone water-soluble polysaccharide (AWSPs) from abandoned abalone shell, and self-healing biomineralization of tooth defects was successfully achieved in vitro. Based on X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), hot field emission scanning electron microscopy (HFESEM) and energy dispersive spectrometer (EDS) analysis, the results showed that the AWSM can efficiently induce remineralization of HAP. The enamel-like HAP was successfully achieved onto etched enamel's surface due to the presence of the AWSM. Moreover, the remineralized effect of eroded enamel was growing with the increase of the AWSM. This study provides a solution to the resource waste and environmental pollution caused by abandoned abalone shell, and we provides a new method for self-healing remineralization of enamel defects by AWSM and develops a novel dental material for potential clinical dentistry application. - Graphical abstract: In this paper, we successfully isolated the abalone water-soluble matrix (AWSM) with 1.53 wt% abalone water-soluble protein (AWSPro) and 2.04 wt% abalone water-soluble polysaccharide (AWSPs) from abandoned abalone shell, and self-healing biomineralization of tooth defects was successfully achieved in vitro by self-organized. Display Omitted - Highlights: • Provides a solution to the resource waste and environmental pollution caused by abandoned abalone shell. • The abalone shell water-soluble matrix contains protein and polysaccharide. • The abalone water-soluble matrix can efficiently induce remineralization of HAP by self-organized. • Achieved self-healing biomineralization of tooth defects in vitro.

A national survey of marine biotoxins in wild-caught abalone in Australia.

Science.gov (United States)

Malhi, Navreet; Turnbull, Alison; Tan, Jessica; Kiermeier, Andreas; Nimmagadda, Rama; McLeod, Catherine

2014-11-01

The first national survey of Australian wild-caught abalone was conducted between September 2012 and December 2013. The aim of the survey was to determine the presence of paralytic shellfish toxins (PSTs), amnesic shellfish toxins (ASTs), and diarrhetic shellfish toxins (DSTs) in wild-caught abalone at levels above the current Codex marine biotoxin limits during the 2013 fishing season. Abalone (n = 190) were collected from 68 abalone-fishing blocks for which the combined annual harvest accounts for 80 % of Australian production. Concurrent seawater samples were collected and enumerated for potentially toxic phytoplankton. The foot and viscera tissues of each abalone sample were analyzed separately for PSTs, ASTs, and DSTs. No samples (abalone foot or viscera) contained toxins at levels exceeding the marine biotoxin limits stipulated by Codex. The resulting prevalence estimate suggests that less than 1.6 % of the commercially caught wild abalone population in Australia were contaminated with marine biotoxins at levels above the regulatory limit during the survey period. ASTs were detected at very low (trace) levels in the foot and viscera tissue of four and three abalone samples, respectively. To our knowledge, this represents the first reported detection of domoic acid in Australian abalone. PSTs also were detected at very low levels in 17 samples of abalone foot tissue and 6 samples of abalone viscera. The association between the low levels of ASTs and PSTs detected in abalone and the presence of potential toxin-producing phytoplankton in seawater samples was weak. DSTs were not detected in any abalone despite the detection of very low levels of DST-producing phytoplankton in a small number (9 of 77) of seawater samples. The results of this survey should be useful for public health risk assessments and provide additional evidence that the prevalence of marine biotoxins in Australian wild-caught abalone is very low.

NUTRITION REQUIREMENT OF CULTURED ABALONE POST LARVAE AND JUVENILES: A REVIEW

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Wa Iba

2008-06-01

Full Text Available Abalone aquaculture attracts wide attention nowadays because of its high market value and depleted of wild stocks. China and Japan are the main producer of abalone from aquaculture followed by other countries such as New Zealand, Australia and US. Most of cultured abalone are temperate species but considerable research efforts have been made to culture tropical abalone in the Philippines, Thailand, and Indonesia. Most of abalone culture still depends on natural food but recent studies have been conducted to develop artificial diet for abalone. This will not only reduce wild harvest of macrolagae but also develop high nutrition diet at low cost. Successful abalone aquaculture is determined by correct nutrition supplement in the diet. As other cultured animal, abalone requires balanced nutrition of carbohydrate, protein, lipid, vitamins, and minerals. As herbivores, abalone can utilize carbohydrate efficiently as energy source and thus only requires low level of protein (range from 27%—40%. Lipid requirements range from 3%—5% while some minerals such as calcium and phosphorus in artificial feed are only needed in small amount, 0.5% of calcium in diets and 0.7% of phosphorus in the diet can improve the growth rate of abalone. There is not available information of vitamin upplementation in the diet but it is suggested that natural food meets the requirement.

Underwater adhesion of abalone: The role of van der Waals and capillary forces

Energy Technology Data Exchange (ETDEWEB)

Lin, A.Y.M., E-mail: albertlin22@yahoo.com [Materials Science and Engineering Program, University of California, San Diego, La Jolla, CA 92093 (United States); Brunner, R. [Department of Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, CA 92093 (United States)] [Department of Nanoengineering, University of California, San Diego, La Jolla, CA 92093 (United States); Chen, P.Y. [Materials Science and Engineering Program, University of California, San Diego, La Jolla, CA 92093 (United States); Talke, F.E. [Department of Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, CA 92093 (United States)] [Center for Magnetic Recording Research, University of California, San Diego, La Jolla, CA 92093 (United States); Meyers, M.A. [Department of Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, CA 92093 (United States)] [Department of Nanoengineering, University of California, San Diego, La Jolla, CA 92093 (United States)] [Materials Science and Engineering Program, University of California, San Diego, La Jolla, CA 92093 (United States)

2009-08-15

The observation of the pedal foot of the red abalone Haliotis rufescens reveals the presence of micrometer-scaled setae terminating in nanometer-sized cylindrical fibrils, with some resemblance to those found on the gecko foot. Atomic force microscopy (AFM) pull-off force measurements on a single seta are compared with theoretical estimates for van der Waals attraction obtained through the Johnson-Kendall-Roberts (JKR) equation, approximately 600 nN, and show agreement. The use of the JKR equation is justified through an analysis of the shape of the fibril extremities (parabolic) as well as their diameter ({approx}200 nm). Measurements under varying humidity conditions indicate that additional capillary interactions play a role, since the pull-off force increases with humidity. It is proposed that both van der Waals and capillary forces play a role in the attachment mechanism of H. rufescens, effectively enabling suction to reach its theoretical limit. Bulk pull-off force measurements on entire live animals yield an average detachment stress of 115 kPa, consistent with theoretical estimates. The setae and nanoscale fibril terminations enable compliance to surfaces with a variety of roughnesses, effectively sealing the interface, in addition to providing capillary and van der Waals forces.

Underwater adhesion of abalone: The role of van der Waals and capillary forces

International Nuclear Information System (INIS)

Lin, A.Y.M.; Brunner, R.; Chen, P.Y.; Talke, F.E.; Meyers, M.A.

2009-01-01

The observation of the pedal foot of the red abalone Haliotis rufescens reveals the presence of micrometer-scaled setae terminating in nanometer-sized cylindrical fibrils, with some resemblance to those found on the gecko foot. Atomic force microscopy (AFM) pull-off force measurements on a single seta are compared with theoretical estimates for van der Waals attraction obtained through the Johnson-Kendall-Roberts (JKR) equation, approximately 600 nN, and show agreement. The use of the JKR equation is justified through an analysis of the shape of the fibril extremities (parabolic) as well as their diameter (∼200 nm). Measurements under varying humidity conditions indicate that additional capillary interactions play a role, since the pull-off force increases with humidity. It is proposed that both van der Waals and capillary forces play a role in the attachment mechanism of H. rufescens, effectively enabling suction to reach its theoretical limit. Bulk pull-off force measurements on entire live animals yield an average detachment stress of 115 kPa, consistent with theoretical estimates. The setae and nanoscale fibril terminations enable compliance to surfaces with a variety of roughnesses, effectively sealing the interface, in addition to providing capillary and van der Waals forces.

Toxic effects of several phthalate esters on the embryos and larvae of abalone Haliotis diversicolor supertexta

Science.gov (United States)

Yang, Zhihui; Zhang, Xiangjing; Cai, Zhonghua

2009-05-01

As the most widely used plasticizers in the world, phthalate esters (PAEs) are potential endocrine disruption compounds (EDCs). In the present study, the toxicity of dimethyl phthalate (DMP), diethyl phthalate (DEP), dibutyl phthalate (DBP), di (2-ethylhexyl) phthalate (DEHP) on embryogenesis and larvae development of the marine univalve Haliotis diversicolor supertexta was examined in laboratory. The results show that the malformation of embryos appeared during the experiment, such as embryos died or lysed, small transparent flocculent rings studded on the periphery of the embryo, and the larvae could failed to hatch. In embryo toxic test, embryos incubated at the highest concentration of DMP, DEP and DBP solutions showed significantly high abnormal rate compared with the control, while DEHP solutions displayed no significant difference. In larval toxic test, in all concentrations of DMP, DEP and DBP solutions, larval settlement rates were low significantly than that of the control. Similarly, DEHP solutions show nearly no effect on the larval settlement. The order of toxicity on embryos and larvae is DBP>DEP>DMP>DEHP. Being a simple and easy stimulation to indoor spawn, sensitive to environmental factors, and short culture time, the embryos of H. diversicolor supertexta can be used to indicate toxicity of the PAEs.

Ultrastructure and Glycoconjugate Pattern of the Foot Epithelium of the Abalone Haliotis tuberculata (Linnaeus, 1758 (Gastropoda, Haliotidae

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I. Bravo Portela

2012-01-01

Full Text Available The foot epithelium of the gastropod Haliotis tuberculata is studied by light and electron microscopy in order to contribute to the understanding of the anatomy and functional morphology of the mollusks integument. Study of the external surface by scanning electron microscopy reveals that the side foot epithelium is characterized by a microvillus border with a very scant presence of small ciliary tufts, but the sole foot epithelium bears a dense field of long cilia. Ultrastructural examination by transmission electron microscopy of the side epithelial cells shows deeply pigmented cells with high electron-dense granular content which are not observed in the epithelial sole cells. Along the pedal epithelium, seven types of secretory cells are present; furthermore, two types of subepithelial glands are located just in the sole foot. The presence and composition of glycoconjugates in the secretory cells and subepithelial glands are analyzed by conventional and lectin histochemistry. Subepithelial glands contain mainly N-glycoproteins rich in fucose and mannose whereas secretory cells present mostly acidic sulphated glycoconjugates such as glycosaminoglycans and mucins, which are rich in galactose, N-acetyl-galactosamine, and N-acetyl-glucosamine. No sialic acid is present in the foot epithelium.

Transcriptome Analysis Revealed Changes of Multiple Genes Involved in Haliotis discus hannai Innate Immunity during Vibrio parahemolyticus Infection.

Science.gov (United States)

Nam, Bo-Hye; Jung, Myunghee; Subramaniyam, Sathiyamoorthy; Yoo, Seung-il; Markkandan, Kesavan; Moon, Ji-Young; Kim, Young-Ok; Kim, Dong-Gyun; An, Cheul Min; Shin, Younhee; Jung, Ho-jin; Park, Jun-hyung

2016-01-01

Abalone (Haliotis discus hannai) is one of the most valuable marine aquatic species in Korea, Japan and China. Tremendous exposure to bacterial infection is common in aquaculture environment, especially by Vibrio sp. infections. It's therefore necessary and urgent to understand the mechanism of H. discus hannai host defense against Vibrio parahemolyticus infection. However studies on its immune system are hindered by the lack of genomic resources. In the present study, we sequenced the transcriptome of control and bacterial challenged H. discus hannai tissues. Totally, 138 MB of reference transcriptome were obtained from de novo assembly of 34 GB clean bases from ten different libraries and annotated with the biological terms (GO and KEGG). A total of 10,575 transcripts exhibiting the differentially expression at least one pair of comparison and the functional annotations highlight genes related to immune response, cell adhesion, immune regulators, redox molecules and mitochondrial coding genes. Mostly, these groups of genes were dominated in hemocytes compared to other tissues. This work is a prerequisite for the identification of those physiological traits controlling H. discus hannai ability to survive against Vibrio infection.

Transcriptome Analysis Revealed Changes of Multiple Genes Involved in Haliotis discus hannai Innate Immunity during Vibrio parahemolyticus Infection

Science.gov (United States)

Nam, Bo-Hye; Jung, Myunghee; Subramaniyam, Sathiyamoorthy; Yoo, Seung-il; Markkandan, Kesavan; Moon, Ji-Young; Kim, Young-Ok; Kim, Dong-Gyun; An, Cheul Min; Shin, Younhee; Jung, Ho-jin; Park, Jun-hyung

2016-01-01

Abalone (Haliotis discus hannai) is one of the most valuable marine aquatic species in Korea, Japan and China. Tremendous exposure to bacterial infection is common in aquaculture environment, especially by Vibrio sp. infections. It’s therefore necessary and urgent to understand the mechanism of H. discus hannai host defense against Vibrio parahemolyticus infection. However studies on its immune system are hindered by the lack of genomic resources. In the present study, we sequenced the transcriptome of control and bacterial challenged H. discus hannai tissues. Totally, 138 MB of reference transcriptome were obtained from de novo assembly of 34 GB clean bases from ten different libraries and annotated with the biological terms (GO and KEGG). A total of 10,575 transcripts exhibiting the differentially expression at least one pair of comparison and the functional annotations highlight genes related to immune response, cell adhesion, immune regulators, redox molecules and mitochondrial coding genes. Mostly, these groups of genes were dominated in hemocytes compared to other tissues. This work is a prerequisite for the identification of those physiological traits controlling H. discus hannai ability to survive against Vibrio infection. PMID:27088873

Transcriptome Analysis Revealed Changes of Multiple Genes Involved in Haliotis discus hannai Innate Immunity during Vibrio parahemolyticus Infection.

Directory of Open Access Journals (Sweden)

Bo-Hye Nam

Full Text Available Abalone (Haliotis discus hannai is one of the most valuable marine aquatic species in Korea, Japan and China. Tremendous exposure to bacterial infection is common in aquaculture environment, especially by Vibrio sp. infections. It's therefore necessary and urgent to understand the mechanism of H. discus hannai host defense against Vibrio parahemolyticus infection. However studies on its immune system are hindered by the lack of genomic resources. In the present study, we sequenced the transcriptome of control and bacterial challenged H. discus hannai tissues. Totally, 138 MB of reference transcriptome were obtained from de novo assembly of 34 GB clean bases from ten different libraries and annotated with the biological terms (GO and KEGG. A total of 10,575 transcripts exhibiting the differentially expression at least one pair of comparison and the functional annotations highlight genes related to immune response, cell adhesion, immune regulators, redox molecules and mitochondrial coding genes. Mostly, these groups of genes were dominated in hemocytes compared to other tissues. This work is a prerequisite for the identification of those physiological traits controlling H. discus hannai ability to survive against Vibrio infection.

Short Communication Towards an abalone weaning diet: evaluation ...

African Journals Online (AJOL)

Survival of post-settlement abalone when 'weaning' them from diatoms onto macroalgae/artificial feed remains unpredictable for farmers. It is hypothesised that spirulina algae, which are high in protein, may be a suitable feed ingredient for weaning abalone. Over a period of 27 days, the growth and survival of juvenile (4–6 ...

Marked changes in neuropeptide expression accompany broadcast spawnings in the gastropod Haliotis asinina

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York Patrick S

2012-05-01

Full Text Available Abstract Introduction A huge diversity of marine species reproduce by synchronously spawning their gametes into the water column. Although this species-specific event typically occurs in a particular season, the precise time and day of spawning often can not be predicted. There is little understanding of how the environment (e.g. water temperature, day length, tidal and lunar cycle regulates a population’s reproductive physiology to synchronise a spawning event. The Indo-Pacific tropical abalone, Haliotis asinina, has a highly predictable spawning cycle, where individuals release gametes on the evenings of spring high tides on new and full moons during the warmer half of the year. These calculable spawning events uniquely allow for the analysis of the molecular and cellular processes underlying reproduction. Here we characterise neuropeptides produced in H. asinina ganglia that are known in egg-laying molluscs to control vital aspects of reproduction. Results We demonstrate that genes encoding APGWamide, myomodulin, the putative proctolin homologue whitnin, FMRFamide, a schistosomin-like peptide (SLP, a molluscan insulin-related peptide (MIP and a haliotid growth-associated peptide (HGAP all are differentially expressed in the anterior ganglia during the two week spawning cycle in both male and female abalone. Each gene has a unique and sex-specific expression profile. Despite these differences, expression levels in most of the genes peak at or within 12 h of the spawning event. In contrast, lowest levels of transcript abundance typically occurs 36 h before and 24 h after spawning, with differences in peak and low expression levels being most pronounced in genes orthologous to known molluscan reproduction neuromodulators. Conclusions Exploiting the predictable semi-lunar spawning cycle of the gastropod H. asinina, we have identified a suite of evolutionarily-conserved, mollusc-specific and rapidly-evolving neuropeptides that appear to

The distribution of the West Coast rock lobster Jasus lalandii ranges ...

African Journals Online (AJOL)

spamer

Key words: abalone Haliotis midae, Jasus lalandii, predation, sea urchins. * Formerly Marine Biology Research Institute, Zoology Department, University of Cape Town, Rondebosch 7701, South Africa; now. 1/19 Alpha Road, Prospect 5082, South Australia. † Formerly Marine Biology Research Institute; now SARDI Aquatic ...

75 FR 29316 - Marine Mammals; File No. 13599

Science.gov (United States)

2010-05-25

...; fax (301) 713-0376; and Southeast Region, NMFS, 263 13th Avenue South, Saint Petersburg, Florida 33701... the Chief, Permits, Conservation and Education Division, at the address listed above. Comments may... black abalone (Haliotis cracherodii). In compliance with the National Environmental Policy Act of 1969...

Generation and analysis of cDNA library from lipopolysaccharide ...

African Journals Online (AJOL)

These immune-related genes include cytidine deaminase, ferritin, nonmuscle myosin essential light chain, cytochrome c oxidase subunit I, CD63 antigen-like protein and lysosomal-associated transmembrane protein. This study may contribute to the understanding of the immune mechanism of gastropod abalone Haliotis ...

Evaluation of abalone β-glucuronidase substitution in current urine hydrolysis procedures.

Science.gov (United States)

Malik-Wolf, Brittany; Vorce, Shawn; Holler, Justin; Bosy, Thomas

2014-04-01

This study examined the potential of abalone β-glucuronidase as a viable and cost effective alternative to current hydrolysis procedures using acid, Helix pomatia β-glucuronidase and Escherichia coli β-glucuronidase. Abalone β-glucuronidase successfully hydrolyzed oxazepam-glucuronide and lorazepam-glucuronide within 5% of the spiked control concentration. Benzodiazepines present in authentic urine specimens were within 20% of the concentrations obtained with the current hydrolysis procedure using H. pomatia β-glucuronidase. JWH 018 N-(5-hydroxypentyl) β-d-glucuronide was hydrolyzed within 10% of the control concentration. Authentic urine specimens showed improved glucuronide cleavage using abalone β-glucuronidase with up to an 85% increase of drug concentration, compared with the results obtained using E. coli β-glucuronidase. The JWH 018 and JWH 073 carboxylic acid metabolites also showed increased drug concentrations of up to 24%. Abalone β-glucuronidase was able to completely hydrolyze a morphine-3-glucuronide control, but only 82% of total morphine was hydrolyzed in authentic urine specimens compared with acid hydrolysis results. Hydrolysis of codeine and hydromorphone varied between specimens, suggesting that abalone β-glucuronidase may not be as efficient in hydrolyzing the glucuronide linkages in opioid compounds compared with acid hydrolysis. Abalone β-glucuronidase demonstrates effectiveness as a low cost option for enzyme hydrolysis of benzodiazepines and synthetic cannabinoids.

Therapeutic potential of abalone and status of bioactive molecules: A comprehensive review.

Science.gov (United States)

Suleria, H A R; Masci, P P; Gobe, G C; Osborne, S A

2017-05-24

Marine organisms are increasingly being investigated as sources of bioactive molecules with therapeutic applications as nutraceuticals and pharmaceuticals. In particular, nutraceuticals are gaining popularity worldwide owing to their therapeutic potential and incorporation in functional foods and dietary supplements. Abalone, a marine gastropod, contains a variety of bioactive compounds with anti-oxidant, anti-thrombotic, anti-inflammatory, anti-microbial, and anti-cancer activities. For thousands of years different cultures have used abalone as a traditional functional food believing consumption provides health benefits. Abalone meat is one of the most precious commodities in Asian markets where it is considered a culinary delicacy. Recent research has revealed that abalone is composed of many vital moieties like polysaccharides, proteins, and fatty acids that provide health benefits beyond basic nutrition. A review of past and present research is presented with relevance to the therapeutic potential of bioactive molecules from abalone.

Marine reserves help preserve genetic diversity after impacts derived from climate variability: Lessons from the pink abalone in Baja California

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Adrián Munguía-Vega

2015-07-01

Full Text Available Genetic diversity is crucial for the adaptation of exploited species like the pink abalone (Haliotis corrugata, faced with threats from climate change, overfishing and impacts associated with aquaculture production. While marine reserves are commonly used to mitigate risks to marine populations, the duration, size, location and larval connectivity needed for a reserve to help conserve genetic resources is still poorly understood. Here, we examine the effects of fishing, reserves, and restocking on the genetic diversity of 10 populations from central Baja California, Mexico, and Southern California, USA. We demonstrate that each population shows characteristic genetic signatures according to recent management decisions. We found high allelic diversity, particularly rare alleles, a larger effective population size and a lack of a recent genetic bottleneck in pink abalones within a small (0.8 km2, recently established (5 years reserve in Baja California, compared to other fished sites after a climatic bottleneck. Higher diversity may result from the presence of older animals in the reserve. Due to its location, the reserve may also act as an important hub connecting distant populations via larval dispersal. In contrast, a population from California showed genetic isolation, loss of allelic diversity and high relatedness, consistent with the collapse of fisheries in the 1990s and their lack of recovery thereafter. In addition, a fished area in Baja California with a history of restocking for over a decade showed an increase in frequency of related individuals and high genetic differentiation from nearby sites that were consistent with the production of larvae from a few adults in the laboratory. A network of strategically placed small marine reserves that considers ocean circulation patterns could help to maintain genetic diversity and connectivity of exploited populations.

Abalone water-soluble matrix for self-healing biomineralization of tooth defects.

Science.gov (United States)

Wen, Zhenliang; Chen, Jingdi; Wang, Hailiang; Zhong, Shengnan; Hu, Yimin; Wang, Zhili; Zhang, Qiqing

2016-10-01

Enamel cannot heal by itself if damaged. Hydroxyapatite (HAP) is main component of human enamel. Formation of enamel-like materials for healing enamel defects remains a challenge. In this paper, we successfully isolated the abalone water-soluble matrix (AWSM) with 1.53wt% the abalone water-soluble protein (AWSPro) and 2.04wt% the abalone water-soluble polysaccharide (AWSPs) from abandoned abalone shell, and self-healing biomineralization of tooth defects was successfully achieved in vitro. Based on X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), hot field emission scanning electron microscopy (HFESEM) and energy dispersive spectrometer (EDS) analysis, the results showed that the AWSM can efficiently induce remineralization of HAP. The enamel-like HAP was successfully achieved onto etched enamel's surface due to the presence of the AWSM. Moreover, the remineralized effect of eroded enamel was growing with the increase of the AWSM. This study provides a solution to the resource waste and environmental pollution caused by abandoned abalone shell, and we provides a new method for self-healing remineralization of enamel defects by AWSM and develops a novel dental material for potential clinical dentistry application. Copyright © 2016 Elsevier B.V. All rights reserved.

Predicting glycogen concentration in the foot muscle of abalone using near infrared reflectance spectroscopy (NIRS).

Science.gov (United States)

Fluckiger, Miriam; Brown, Malcolm R; Ward, Louise R; Moltschaniwskyj, Natalie A

2011-06-15

Near infrared reflectance spectroscopy (NIRS) was used to predict glycogen concentrations in the foot muscle of cultured abalone. NIR spectra of live, shucked and freeze-dried abalones were modelled against chemically measured glycogen data (range: 0.77-40.9% of dry weight (DW)) using partial least squares (PLS) regression. The calibration models were then used to predict glycogen concentrations of test abalone samples and model robustness was assessed from coefficient of determination of the validation (R2(val)) and standard error of prediction (SEP) values. The model for freeze-dried abalone gave the best prediction (R2(val) 0.97, SEP=1.71), making it suitable for quantifying glycogen. Models for live and shucked abalones had R2(val) of 0.86 and 0.90, and SEP of 3.46 and 3.07 respectively, making them suitable for producing estimations of glycogen concentration. As glycogen is a taste-active component associated with palatability in abalone, this study demonstrated the potential of NIRS as a rapid method to monitor the factors associated with abalone quality. Copyright © 2011 Elsevier Ltd. All rights reserved.

Towards adaptive approaches to management of the South African ...

African Journals Online (AJOL)

The South African abalone Haliotis midae resource is widely perceived as being under threat of overexploitation as a result of increased poaching. In this paper, reservations are expressed about using catch per unit effort as the sole index of abundance when assessing this fishery, particularly because of the highly ...

A decade of illegal fishing in Table Mountain National Park (2000 ...

African Journals Online (AJOL)

Illegal fishing activities are reported to be on the increase in South Africa, including in its marine protected areas (MPAs). Research is presented on the nature and the scale of illegal fishing in Table Mountain National Park (TMNP) by analysing the numbers of abalone Haliotis midae and West Coast rock lobster Jasus ...

Integrated culture of silver kob Argyrosomus inodorus and ...

African Journals Online (AJOL)

South African abalone Haliotis midae farms utilise large volumes of seawater (c. 500–1 500 l s–1) and produce relatively dilute effluents that are potentially suitable for the integrated culture of other species. To test this hypothesis, a marine finfish, silver kob Argyrosomus inodorus, and a detritivorous polychaete, bloodworm ...

Evaluation of de novo assembly technique in the South African abalone Haliotis midae transcriptome: A comparison from Illumina and 454 systems

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Barbara Picone

2016-12-01

Full Text Available Next generation sequencing platforms have recently been used to rapidly characterize transcriptome sequences from a number of non-model organisms. The present study compares two of the most frequently used platforms, the Roche 454-pyrosequencing and the Illumina sequencing-by-synthesis (SBS, on the same RNA sample obtained from an intertidal gastropod mollusc species, Haliotis midae. All the sequencing reads were deposited in the Short Read Archive (SRA database are retrievable under the accession number [SRR071314 (Illumina Genome Analyzer II] and [SRR1737738, SRR1737737, SRR1737735, SRR1737734 (454 GS FLX] in the SRA database of NCBI. Three transcriptomes, composed of either pure 454 or Illumina reads or a mixture of read types (Hybrid, were assembled using CLC Genomics Workbench software. Illumina assemblies performed the best de novo transcriptome characterization in terms of contig length, whereas the 454 assemblies tended to improve the complete assembly of gene transcripts. Both the Hybrid and Illumina assemblies produced longer contigs covering more of the transcriptome than 454 assemblies. However, the addition of 454 significantly increased the number of genes annotated.

The effects of drilling muds on marine invertebrate larvae and adults

International Nuclear Information System (INIS)

Raimondi, P.T.; Barnett, A.M.; Krause, P.R.

1997-01-01

A series of laboratory experiments tested the effects of drilling muds from an active platform off southern California on larvae and adults of marine invertebrates. Red abalone (Haliotis rufescens) were used to determine effects of drilling muds on fertilization, early development, survivorship, and settlement, and experiments on adult brown cup corals (Paracyathus stearnsii) tested effects on adult survivorship, viability, and tissue loss. Exposures to drilling muds did not have an effect on abalone fertilization or early development. However, several exposures to drilling muds resulted in weak, but significant, positive effects of drilling muds on settlement of competent larvae. In contrast, settlement of red abalone larvae on natural coralline algal crusts decreased with increasing concentrations of drilling muds. This suggests that drilling muds affect either the abalone's ability to detect natural settlement inducers, or they affect the inducer itself. Exposure of brown cup corals to concentrations of drilling muds adversely impacted their survivorship and viability. These effects were likely caused by increased tissue mortality of the coral polyps

Abalone Hemocyanin Blocks the Entry of Herpes Simplex Virus 1 into Cells: a Potential New Antiviral Strategy

Science.gov (United States)

Talaei Zanjani, Negar; Miranda-Saksena, Monica; Valtchev, Peter; Hueston, Linda; Diefenbach, Eve; Sairi, Fareed; Gomes, Vincent G.

2015-01-01

A marine-derived compound, abalone hemocyanin, from Haliotis rubra was shown to have a unique mechanism of antiviral activity against herpes simplex virus 1 (HSV-1) infections. In vitro assays demonstrated the dose-dependent and inhibitory effect of purified hemocyanin against HSV-1 infection in Vero cells with a 50% effective dose (ED50) of 40 to 50 nM and no significant toxicity. In addition, hemocyanin specifically inhibited viral attachment and entry by binding selectively to the viral surface glycoproteins gD, gB, and gC, probably by mimicking their receptors. However, hemocyanin had no effect on postentry events and did not block infection by binding to cellular receptors for HSV. By the use of different mutants of gD and gB and a competitive heparin binding assay, both protein charge and conformation were shown to be the driving forces of the interaction between hemocyanin and viral glycoproteins. These findings also suggested that hemocyanin may have different motifs for binding to each of the viral glycoproteins B and D. The dimer subunit of hemocyanin with a 10-fold-smaller molecular mass exhibited similar binding to viral surface glycoproteins, showing that the observed inhibition did not require the entire multimer. Therefore, a small hemocyanin analogue could serve as a new antiviral candidate for HSV infections. PMID:26643336

Short Communication Effects of heavy metals on the development ...

African Journals Online (AJOL)

Despite a growing abalone Haliotis midae industry in South Africa, few studies have measured the effects of heavy metals on larval survival and growth in the face of recent increases in marine pollution. The aim of this study was to quantify the effect of copper on survival and zinc on development of H. midae larvae. Larvae ...

Variation in rates of early development in Haliotis asinina generate competent larvae of different ages

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Jackson Daniel J

2012-02-01

Full Text Available Abstract Introduction Inter-specific comparisons of metazoan developmental mechanisms have provided a wealth of data concerning the evolution of body form and the generation of morphological novelty. Conversely, studies of intra-specific variation in developmental programs are far fewer. Variation in the rate of development may be an advantage to the many marine invertebrates that posses a biphasic life cycle, where fitness commonly requires the recruitment of planktonically dispersing larvae to patchily distributed benthic environments. Results We have characterised differences in the rate of development between individuals originating from a synchronised fertilisation event in the tropical abalone Haliotis asinina, a broadcast spawning lecithotrophic vetigastropod. We observed significant differences in the time taken to complete early developmental events (time taken to complete third cleavage and to hatch from the vitelline envelope, mid-larval events (variation in larval shell development and late larval events (the acquisition of competence to respond to a metamorphosis inducing cue. We also provide estimates of the variation in maternally provided energy reserves that suggest maternal provisioning is unlikely to explain the majority of the variation in developmental rate we report here. Conclusions Significant differences in the rates of development exist both within and between cohorts of synchronously fertilised H. asinina gametes. These differences can be detected shortly after fertilisation and generate larvae of increasingly divergent development states. We discuss the significance of our results within an ecological context, the adaptive significance of mechanisms that might maintain this variation, and potential sources of this variation.

Accumulation of Co by abalone, 1

International Nuclear Information System (INIS)

Ueda, Taiji; Suzuki, Yuzuru; Nakamura, Ryoichi; Nakahara, Motokazu; Shimizu, Chiaki.

1982-01-01

The appearance of radioactive Co in the liver of abalone from sea water was examined to consider the effect of chemical forms of Co(CoCl 2 and cyanocobalamin; vitamin B 12 ) in sea water upon the metabolisms in marine organisms. Organic 57 Co(cyanocobalamin) from sea water appeared in the liver of abalone combining with a constituent with a molecular weight of 4 x 10 4 . The constituent had the activity of vitamin B 12 , while inorganic 60 Co(CoCl 2 ) appeared combining with three constituents with molecular weights more than or equal to 1.5 x 10 6 , 7 x 10 3 and less than or equal to 1.5 x 10 3 which did not show the activities of vitamin B 12 . The effect of chemical forms of Co in sea water is significant in its accumulation by some species of marine organisms. (author)

Status of abalone fishery and experiential mariculture as a resource conservation strategy in Carot, Anda, Pangasinan

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Emmanuel C. Capinpin, Jr.

2013-06-01

Full Text Available The study described the abalone f ishery in Carot, Anda, Pangasinan to develop mariculture and to reseed a part of the harvest as a resource conservation strategy. The abalone fishery of Anda is artisanal or smallscale, typif ied by f ishers gleaning or free-diving on shallow rocky areas which are the typical habitat of abalone. Low densities of 1.67 to 8 individuals per 250 m2 were observed. Local f ishers have knowledge of productive f ishing areas. Hence, cage culture of abalone in these areas could be a viable resource conservation strategy as they serve as reproductive reserves to supply larvae for continued productivity of the f ishing grounds. Abalone mariculture following the Farmer Field School (FFS concept was explored to address both resource management and economic needs. As a resource enhancement activity, mariculture guarantees that cultured abalone are allowed to grow to maturity before harvested, while some are retained to restock a marine sanctuary. Sincemariculture makes possible the aggregation of individuals, the probability that fertilization would take place is increased. As supplemental source of livelihood, abalone is a high value commodity and its culture can help augment the income of f ishers. Small abalone (3-4 cm can be cultured further for 3-4 months to increase their size and weight. Mariculture should be done from November to May to avoid the rainy season and improve survivorship. The experiential activity was successful because it became a means for the f ishers to experienceresource management. Under the FFS, the researcher became a facilitator and mentored the cooperators in learning from their experience. The lessons sharpened the f ishers’ skills in observation, problem-solving, decision-making, and critical thinking. This enabled them to gain an appreciation of their resource.

Effect of abalone farming on sediment geochemistry in the Shallow Sea near Wando, South Korea

Science.gov (United States)

Kang, Jeongwon; Lee, Yeon Gyu; Jeong, Da Un; Lee, Jung Sick; Choi, Yang Ho; Shin, Yun Kyung

2015-12-01

Wando County has grown up to 93% of the total abalone produced in South Korea since the late 1990s; however, this production has been decreasing in recent years. The objectives of this study were to understand the potential contamination risks of abalone farming and to examine the influence of intensive abalone farming on sediment quality by analyzing grain-size composition, organic matter (total organic carbon (TOC), total nitrogen (TN), total sulfur (TS)) and heavy metal content, pH, and 210Pb geochronology. The results of organic matter analysis from surface and core sediment (length: 64 cm) showed that the area around the abalone farm had oxic marine-to-brackish conditions, but that the area directly below an abalone cage (location 7) had reductive conditions, with a C/S ratio of ~2. The average TN levels in the surface and core sediments were 0.25% and 0.29%, respectively, and this was predominantly due to the use of seaweed for feed. The low sediment pH (surface, 7.23; core, 7.04), indicates that acidification of the bottom sediment has gradually increased since the initiation of abalone farming and is likely due to the continuous accumulation of uneaten feed and feces. Heavy metal pollution was not apparent based on the examination of EF and Igeo, although the excess metal flux of Ni, Pb, Cu, Co, As, and Cd increased toward surface of the sediment core. These sediment changes may be caused by the rapid accumulation (sedimentation rate: 1.45 cm/year) of sludge discharged from the abalone farm and may be controlled by tidal currents, physiography, water depth, and tidal ranges.

Abalone visceral extract inhibit tumor growth and metastasis by modulating Cox-2 levels and CD8+ T cell activity

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II Kim Jae

2010-10-01

Full Text Available Abstract Background Abalone has long been used as a valuable food source in East Asian countries. Although the nutritional importance of abalone has been reported through in vitro and in vivo studies, there is little evidence about the potential anti-tumor effects of abalone visceral extract. The aim of the present study is to examine anti-tumor efficacy of abalone visceral extract and to elucidate its working mechanism. Methods In the present study, we used breast cancer model using BALB/c mouse-derived 4T1 mammary carcinoma and investigated the effect of abalone visceral extract on tumor development. Inhibitory effect against tumor metastasis was assessed by histopathology of lungs. Cox-2 productions by primary and secondary tumor were measured by real-time RT-PCR and immunoblotting (IB. Proliferation assay based on [3H]-thymidine incorporation and measurement of cytokines and effector molecules by RT-PCR were used to confirm tumor suppression efficacy of abalone visceral extract by modulating cytolytic CD8+ T cells. The cytotoxicity of CD8+ T cell was compared by JAM test. Results Oral administration of abalone visceral extract reduced tumor growth (tumor volume and weight and showed reduced metastasis as confirmed by decreased level of splenomegaly (spleen size and weight and histological analysis of the lung metastasis (gross analysis and histological staining. Reduced expression of Cox-2 (mRNA and protein from primary tumor and metastasized lung was also detected. In addition, treatment of abalone visceral extract increased anti-tumor activities of CD8+ T cells by increasing the proliferation capacity and their cytolytic activity. Conclusions Our results suggest that abalone visceral extract has anti-tumor effects by suppressing tumor growth and lung metastasis through decreasing Cox-2 expression level as well as promoting proliferation and cytolytic function of CD8+ T cells.

Abalone visceral extract inhibit tumor growth and metastasis by modulating Cox-2 levels and CD8+ T cell activity.

Science.gov (United States)

Lee, Choong-Gu; Kwon, Ho-Keun; Ryu, Jae Ha; Kang, Sung Jin; Im, Chang-Rok; Ii Kim, Jae; Im, Sin-Hyeog

2010-10-20

Abalone has long been used as a valuable food source in East Asian countries. Although the nutritional importance of abalone has been reported through in vitro and in vivo studies, there is little evidence about the potential anti-tumor effects of abalone visceral extract. The aim of the present study is to examine anti-tumor efficacy of abalone visceral extract and to elucidate its working mechanism. In the present study, we used breast cancer model using BALB/c mouse-derived 4T1 mammary carcinoma and investigated the effect of abalone visceral extract on tumor development. Inhibitory effect against tumor metastasis was assessed by histopathology of lungs. Cox-2 productions by primary and secondary tumor were measured by real-time RT-PCR and immunoblotting (IB). Proliferation assay based on [3H]-thymidine incorporation and measurement of cytokines and effector molecules by RT-PCR were used to confirm tumor suppression efficacy of abalone visceral extract by modulating cytolytic CD8+ T cells. The cytotoxicity of CD8+ T cell was compared by JAM test. Oral administration of abalone visceral extract reduced tumor growth (tumor volume and weight) and showed reduced metastasis as confirmed by decreased level of splenomegaly (spleen size and weight) and histological analysis of the lung metastasis (gross analysis and histological staining). Reduced expression of Cox-2 (mRNA and protein) from primary tumor and metastasized lung was also detected. In addition, treatment of abalone visceral extract increased anti-tumor activities of CD8+ T cells by increasing the proliferation capacity and their cytolytic activity. Our results suggest that abalone visceral extract has anti-tumor effects by suppressing tumor growth and lung metastasis through decreasing Cox-2 expression level as well as promoting proliferation and cytolytic function of CD8+ T cells.

Insights into adhesion of abalone: A mechanical approach.

Science.gov (United States)

Li, Jing; Zhang, Yun; Liu, Sai; Liu, Jianlin

2018-01-01

Many living creatures possess extremely strong capability of adhesion, which has aroused great attention of many scientists and engineers. Based on the self-developed equipment, we measured the normal and shear adhesion strength of the abalone underwater and out of water on different contact surfaces. It is found that the adhesion force of the abalone can amount to 200 or 300 times its body weight. The effects of wettability and roughness of the surface, and the frictional coefficient of mucus on the adhesion strength have been discussed. The theoretical calculation manifests that the normal adhesion force mainly stems from the suction pressure, van der Waals force and capillary force of the pedal, and their limit values are given. These findings may provide some inspirations to engineer new-typed materials, micro-devices, adhesives and medicine. Copyright © 2017 Elsevier Ltd. All rights reserved.

Using Local Ecological Knowledge and Environmental Education in Resource Management of Abalone in Carot, Anda, Pangasinan

Directory of Open Access Journals (Sweden)

Emmanuel C. Capinpin, Jr.

2012-06-01

Full Text Available The objectives of the present study were to (1 determine the local ecological knowledge (LEK of abalone gatherers through interviews and mentoring, and assess the correspondence between scientific information and LEK, so that areas where local knowledge may be most useful in resource management could be identified, and (2 to empower selected gatherers/farmers with knowledge and technical skills through environmental education to help develop or build their capacity to become sustainable resource managers. The LEK of abalone fishers was determined using three complementary approaches – group interview, individual interview, and mentoring sessions. Local fishers possess a wealth of knowledge about the interactions of species gained through many years of observations, and this knowledge may be useful in guiding biologists in ecological restoration or management regimes. Additionally, the fishers’ LEK, validated by modern scientific ecological findings, could be a source of important and effective ideas in resource management. The knowledge of the abalone gatherers about important abalone fishing grounds should help in pinpointing critical areas that need to be managed. Abalone mariculture in cages should be set up in these areas to routinely create dense breeding populations which can help in enhancing recovery and in providing fishers with a source of additional income. The continued enforcement of marine protected areas and the periodic release or reseeding of abalone in sanctuaries could also be considered viable resource management options. Other recommendations for resource management based on gathered local knowledge and lessons learned from the environmental education (EE seminars are also presented.

Dietary fish oil supplements increase tissue n-3 fatty acid composition and expression of delta-6 desaturase and elongase-2 in Jade Tiger hybrid abalone.

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Mateos, Hintsa T; Lewandowski, Paul A; Su, Xiao Q

2011-08-01

This study was conducted to investigate the effects of fish oil (FO) supplements on fatty acid composition and the expression of ∆6 desaturase and elongase 2 genes in Jade Tiger abalone. Five test diets were formulated to contain 0.5, 1.0, 1.5, 2.0 and 2.5% of FO respectively, and the control diet was the normal commercial abalone diet with no additional FO supplement. The muscle, gonad and digestive glands (DG) of abalone fed with all of the five test diets showed significantly high levels of total n-3 polyunsaturated fatty acid (PUFA), eicosapentaenoic acid (EPA), docosapentaenoic acid n-3 (DPAn-3), and docosahexaenoic acid (DHA) than the control group. In all three types of tissue, abalone fed diet supplemented with 1.5% FO showed the highest level of these fatty acids (P abalone fed diet supplemented with 2% FO (P abalone fed diet supplemented with 1.5% FO (P abalone fed with diet containing 0.5% FO supplement (P abalone, with 1.5% being the most effective supplementation level.

From untargeted LC-QTOF analysis to characterisation of opines in abalone adductor muscle: Theory meets practice.

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Venter, Leonie; Jansen van Rensburg, Peet J; Loots, Du Toit; Vosloo, Andre; Lindeque, Jeremie Zander

2017-12-15

Abalone have a unique ability to use pyruvate, various amino acids and dehydrogenases, to produce opines as means to prevent the accumulation of NADH during anaerobic conditions. In this study, the theoretical masses, formulae and fragment patterns of butylated opines were used to predict which of these compounds could be found in the abalone adductor muscle using untargeted liquid chromatography quadrupole time-of flight-mass spectrometry. These findings were validated using synthesised opine standards. In essence alanopine, lysopine, strombine and tauropine produced in abalone adductor muscle could be characterised using the highest identification confidence levels. Copyright © 2017 Elsevier B.V. All rights reserved.

Effect of Abalone Hydrolysates Encapsulated by Double Emulsion on the Physicochemical and Sensorial Properties of Fresh Cheese.

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Choi, HeeJeong; Kim, Soo-Jin; Lee, Sang-Yoon; Choi, Mi-Jung

2017-01-01

The intake of dietary salt through food now exceeds current nutritional recommendations and is thought to have negative effects on human health, such as the increasing prevalence of hypertension. This study was performed to investigate whether W 1 /O/W 2 double emulsions can be used to enhance the saltiness of cheese without increasing the salt content (W 1 is distilled water or 1% abalone hydrolysate, and W 2 is 1% NaCl or 1% abalone hydrolysate + 1% NaCl solution). We also investigated the effect of adding abalone hydrolysate to the double emulsion as a saltiness enhancer. The cheeses were physico-chemically evaluated to determine curd yield, pH value, moisture content, color, texture, salt release rate, and sensory properties. No significant differences were observed in curd yield, pH value, moisture content, lightness, or redness between the cheeses made with and without the double emulsion. However, in the evaluation of salt release rate, fresh cheese made with double emulsion (W 1 = distilled water, W 2 = 1% NaCl + 1% abalone hydrolysate) was detected earlier than the control or the other treatments. In the sensory evaluation, fresh cheese made with the double emulsion showed higher scores for saltiness and overall preference than the control or the other treatments. We concluded that abalone hydrolysate encapsulated in a double emulsion (W 1 is water and W 2 is abalone hydrolysate and NaCl solution) could enhance the saltiness of fresh cheese while maintaining the same salt concentration, without altering its physical properties.

Abalone Muscle Texture Evaluation and Prediction Based on TPA Experiment

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Jiaxu Dong

2017-01-01

Full Text Available The effects of different heat treatments on abalones’ texture properties and sensory characteristics were studied. Thermal processing of abalone muscle was analyzed to determine the optimal heat treatment condition based on fuzzy evaluation. The results showed that heat treatment at 85°C for 1 hour had certain desirable effects on the properties of the abalone meat. Specifically, a back propagation (BP neural network was introduced to predict the equations of statistically significant sensory hardness, springiness, and smell using the texture data gained through TPA (texture profile analysis experiments as input and sensory evaluation data as the desired output. The final outcome was that the predictability was proved to be satisfactory, with an average error of 6.93%.

The development of a loop-mediated isothermal amplification assay for rapid and sensitive detection of abalone herpesvirus DNA.

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Chen, M H; Kuo, S T; Renault, T; Chang, P H

2014-02-01

A loop-mediated isothermal amplification (LAMP) assay was developed for the detection of abalone herpesvirus DNA. Two pairs of primers were designed, based on the sequence of the DNA polymerase gene of abalone herpesvirus. The reaction temperature and time were optimized to 63°C and 60min, respectively. LAMP amplicons were analyzed by 2% agarose gel electrophoresis or by visual inspection of a colour change emitted by fluorescent dye. The method developed was specific for the detection of abalone herpesvirus, without cross-reactions with other tested herpesviruses including ostreid herpesvirus 1 (OsHV-1), European eel herpesvirus, koi herpesvirus (KHV) and an avian herpesvirus. The LAMP assay was 100 folds more sensitive than a conventional PCR and 10 folds less sensitive than a SYBR Green PCR. These results indicate that the developed LAMP assay is a simple, rapid, sensitive, specific and reliable technique for the detection of abalone herpesvirus. Copyright © 2013 Elsevier B.V. All rights reserved.

Abalone Protein Hydrolysates: Preparation, Angiotensin I Converting Enzyme Inhibition and Cellular Antioxidant Activity.

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Park, Soo Yeon; Je, Jae-Young; Hwang, Joung-Youl; Ahn, Chang-Bum

2015-09-01

Abalone protein was hydrolyzed by enzymatic hydrolysis and the optimal enzyme/substrate (E/S) ratios were determined. Abalone protein hydrolysates (APH) produced by Protamex at E/S ratio of 1:100 showed angiotensin I converting enzyme inhibitory activity with IC50 of 0.46 mg/mL, and APH obtained by Flavourzyme at E/S ratio of 1:100 possessed the oxygen radical absorbance capacity value of 457.6 μM trolox equivalent/mg sample. Flavourzyme abalone protein hydrolysates (FAPH) also exhibited H2O2 scavenging activity with IC50 of 0.48 mg/mL and Fe(2+) chelating activity with IC50 of 2.26 mg/mL as well as high reducing power. FAPH significantly (P<0.05) protected H2O2-induced hepatic cell damage in cultured hepatocytes, and the cell viability was restored to 90.27% in the presence of FAPH. FAPH exhibited 46.20% intracellular ROS scavenging activity and 57.89% lipid peroxidation inhibition activity in cultured hepatocytes. Overall, APH may be useful as an ingredient for functional foods.

Cytogenetic analysis and chromosomal characteristics of the polymorphic 18S rDNA of Haliotis discus hannai from Fujian, China.

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Haishan Wang

Full Text Available We report on novel chromosomal characteristics of Haliotis discus hannai from a breeding population at Fujian, China. The karyotypes of H. discus hannai we obtained from an abalone farm include a common type 2n = 36 = 10M + 8SM (82% and two rare types 2n = 36 = 11M + 7SM (14% and 2n = 36 = 10M + 7SM + 1ST (4%. The results of silver staining showed that the NORs of H. discus hannai were usually located terminally on the long arms of chromosome pairs 14 and 17, NORs were also sometimes located terminally on the short arms of other chromosomes, either metacentric or submetacentric pairs. The number of Ag-nucleoli ranged from 2 to 8, and the mean number was 3.61 ± 0.93. Among the scored interphase cells, 41% had 3 detectable nucleoli and 37% had 4 nucleoli. The 18S rDNA FISH result is the first report of the location of 18S rDNA genes in H. discus hannai. The 18S rDNA locations were highly polymorphic in this species. Copies of the gene were observed in the terminal of long or/and short arms of submetacentric or/and metacentric chromosomes. Using FISH with probe for vertebrate-like telomeric sequences (CCCTAA3 displayed positive green FITC signals at telomere regions of all analyzed chromosome types. We found about 7% of chromosomes had breaks in prophase. A special form of nucleolus not previously described from H. discus hannai was observed in some interphase cells. It consists of many small silver-stained nucleoli gathered together to form a larger nucleolus and may correspond to prenucleolar bodies.

As abalone grow, they change their habitat and be- haviour ...

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rock lobster Jasus lalandii, which eat sea urchins, have been ... change with abalone size (McCormick et al. 1994), .... rock faces. Any boulder too large to roll was classified as a ..... Social behaviour of juvenile red sea urchins, Strongylo-.

The growth performance of Jade Tiger cultured abalone fed diets supplemented with fish oil and vegetable oils.

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Mateos, Hintsa T; Lewandowski, Paul A; Su, Xiao Q

2013-04-01

The effects of fish oil (FO) supplementation and the dietary replacement of FO with flaxseed oil (FlaxO) and canola oil (CO) on the growth of cultured abalone was investigated. The study involved three growth experiments: (E1) diets containing 0.5, 1.0, 1.5, 2.0 and 2.5% of FO, respectively; (E2) diets in which FO was serially replaced by 25, 50, 75 and 100% FlaxO, respectively; and (E3) diets in which FO was serially replaced by 25, 50, 75 and 100% CO, respectively. In Experiment 1, abalone fed a diet supplemented with 1.5% FO showed a significantly higher (121.2 ± 1.1 mg day(-1)) daily growth rate of weight (DGRw ) compared to control (70.1 ± 1.71 mg day(-1)). In Experiment 2, abalone fed 1.5% FO diet and diets containing 25-75% FlaxO showed no significant differences in DGRw. The diet containing 100% FlaxO showed significantly lower (63.3 ± 6.7 mg day(-1)) DGRw. In Experiment 3, abalone fed diets containing 25% and 50% CO showed similar DGRw as those fed a 1.5% FO diet. The diet containing 75% and 100% CO showed significantly lower (63.7 ± 5.0 to 95.4 ± 5.1 mg day(-1)) DGRw. Supplementation with 1.5% of dietary FO can improve growth performance in cultured abalone. It is feasible to replace 75% of dietary FO with FlaxO and 50% of dietary FO with CO, without negative effect on growth performance. © 2012 Society of Chemical Industry.

Nanoscale elasticity mappings of micro-constituents of abalone shell by band excitation-contact resonance force microscopy

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Li, Tao; Zeng, Kaiyang

2014-01-01

The macroscopic mechanical properties of the abalone shell have been studied extensively in the literature, but the in situ nanoscale elasticity of various micro-constituents in the shell have not been characterized and reported yet. In this study, the nanoscale elasticity mappings including different micro-constituents in abalone shell were observed by using the Contact Resonance Force Microscopy (CR-FM) technique. CR-FM is one of the advanced scanning probe microscopy techniques that is able to quantify the local elastic moduli of various materials in a non-destructive manner. Instead of an average value, an elasticity mapping that reveals the nanoscale variations of elastic moduli with location can be extracted and correlated with the topography of the structure. Therefore in this study, by adopting the CR-FM technique that is incorporated with the band excitation technique, the elasticity variations of the abalone shell caused by different micro-constituents and crystal orientations are reported, and the elasticity values of the aragonite and calcite nanograins are quantified.The macroscopic mechanical properties of the abalone shell have been studied extensively in the literature, but the in situ nanoscale elasticity of various micro-constituents in the shell have not been characterized and reported yet. In this study, the nanoscale elasticity mappings including different micro-constituents in abalone shell were observed by using the Contact Resonance Force Microscopy (CR-FM) technique. CR-FM is one of the advanced scanning probe microscopy techniques that is able to quantify the local elastic moduli of various materials in a non-destructive manner. Instead of an average value, an elasticity mapping that reveals the nanoscale variations of elastic moduli with location can be extracted and correlated with the topography of the structure. Therefore in this study, by adopting the CR-FM technique that is incorporated with the band excitation technique, the

Accumulation of Co by abalone, 1. Effect of chemical form

Energy Technology Data Exchange (ETDEWEB)

Ueda, T.; Suzuki, Y.; Nakamura, R.; Nakahara, M. (National Inst. of Radiological Sciences, Nakaminato, Ibaraki (Japan). Nakaminato Lab. Brance Office); Shimizu, C.

1982-03-01

The appearance of radioactive Co in the liver of abalone from sea water was examined to consider the effect of chemical forms of Co(CoCl/sub 2/ and cyanocobalamin; vitamin B/sub 12/) in sea water upon the metabolisms in marine organisms. Organic /sup 57/Co(cyanocobalamin) from sea water appeared in the liver of abalone combining with a constituent with a molecular weight of 4 x 10/sup 4/. The constituent had the activity of vitamin B/sub 12/, while inorganic /sup 60/Co(CoCl/sub 2/) appeared combining with three constituents with molecular weights more than or equal to 1.5 x 10/sup 6/, 7 x 10/sup 3/ and less than or equal to 1.5 x 10/sup 3/ which did not show the activities of vitamin B/sub 12/. The effect of chemical forms of Co in sea water is significant in its accumulation by some species of marine organisms.

Whole-genome sequencing reveals that Shewanella haliotis Kim et al. 2007 can be considered a later heterotypic synonym of Shewanella algae Simidu et al. 1990.

Science.gov (United States)

Szeinbaum, Nadia; Kellum, Cailin E; Glass, Jennifer B; Janda, J Michael; DiChristina, Thomas J

2018-04-01

Previously, experimental DNA-DNA hybridization (DDH) between Shewanellahaliotis JCM 14758 T and Shewanellaalgae JCM 21037 T had suggested that the two strains could be considered different species, despite minimal phenotypic differences. The recent isolation of Shewanella sp. MN-01, with 99 % 16S rRNA gene identity to S. algae and S. haliotis, revealed a potential taxonomic problem between these two species. In this study, we reassessed the nomenclature of S. haliotis and S. algae using available whole-genome sequences. The whole-genome sequence of S. haliotis JCM 14758 T and ten S. algae strains showed ≥97.7 % average nucleotide identity and >78.9 % digital DDH, clearly above the recommended species thresholds. According to the rules of priority and in view of the results obtained, S. haliotis is to be considered a later heterotypic synonym of S. algae. Because the whole-genome sequence of Shewanella sp. strain MN-01 shares >99 % ANI with S. algae JCM 14758 T , it can be confidently identified as S. algae.

Effects for rapid conversion from abalone shell to hydroxyapaptite nanosheets by ionic surfactants.

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Zhong, Shengnan; Wen, Zhenliang; Chen, Jingdi; Li, Qian; Shi, Xuetao; Ding, Shinnjyh; Zhang, Qiqing

2017-08-01

Hydroxyapatite (HAP) has been widely used for repairing or substituting human hard tissues. In this paper, two typical ionic surfactants, cation hexadecyltrimethylammonium bromide (CTAB) and anion sodium dodecyl sulfate (SDS), were used for rapid conversion of HAP from abalone shell. From field emission scanning electron microscopy (FESEM), the prepared HAP is flake-like structure. From X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and thermal analysis, these samples contain a small amount of calcium carbonate whose content gradually increases by increasing the surfactants. The results showed that the HAP formed fast on the layer of abalone shell powder with the assistance of CTAB and SDS. Copyright © 2017 Elsevier B.V. All rights reserved.

A Bacteriophage-Related Chimeric Marine Virus Infecting Abalone

Science.gov (United States)

Zhuang, Jun; Cai, Guiqin; Lin, Qiying; Wu, Zujian; Xie, Lianhui

2010-01-01

Marine viruses shape microbial communities with the most genetic diversity in the sea by multiple genetic exchanges and infect multiple marine organisms. Here we provide proof from experimental infection that abalone shriveling syndrome-associated virus (AbSV) can cause abalone shriveling syndrome. This malady produces histological necrosis and abnormally modified macromolecules (hemocyanin and ferritin). The AbSV genome is a 34.952-kilobase circular double-stranded DNA, containing putative genes with similarity to bacteriophages, eukaryotic viruses, bacteria and endosymbionts. Of the 28 predicted open reading frames (ORFs), eight ORF-encoded proteins have identifiable functional homologues. The 4 ORF products correspond to a predicted terminase large subunit and an endonuclease in bacteriophage, and both an integrase and an exonuclease from bacteria. The other four proteins are homologous to an endosymbiont-derived helicase, primase, single-stranded binding (SSB) protein, and thymidylate kinase, individually. Additionally, AbSV exhibits a common gene arrangement similar to the majority of bacteriophages. Unique to AbSV, the viral genome also contains genes associated with bacterial outer membrane proteins and may lack the structural protein-encoding ORFs. Genomic characterization of AbSV indicates that it may represent a transitional form of microbial evolution from viruses to bacteria. PMID:21079776

A bacteriophage-related chimeric marine virus infecting abalone.

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Jun Zhuang

Full Text Available Marine viruses shape microbial communities with the most genetic diversity in the sea by multiple genetic exchanges and infect multiple marine organisms. Here we provide proof from experimental infection that abalone shriveling syndrome-associated virus (AbSV can cause abalone shriveling syndrome. This malady produces histological necrosis and abnormally modified macromolecules (hemocyanin and ferritin. The AbSV genome is a 34.952-kilobase circular double-stranded DNA, containing putative genes with similarity to bacteriophages, eukaryotic viruses, bacteria and endosymbionts. Of the 28 predicted open reading frames (ORFs, eight ORF-encoded proteins have identifiable functional homologues. The 4 ORF products correspond to a predicted terminase large subunit and an endonuclease in bacteriophage, and both an integrase and an exonuclease from bacteria. The other four proteins are homologous to an endosymbiont-derived helicase, primase, single-stranded binding (SSB protein, and thymidylate kinase, individually. Additionally, AbSV exhibits a common gene arrangement similar to the majority of bacteriophages. Unique to AbSV, the viral genome also contains genes associated with bacterial outer membrane proteins and may lack the structural protein-encoding ORFs. Genomic characterization of AbSV indicates that it may represent a transitional form of microbial evolution from viruses to bacteria.

Predicting the distribution of commercially important invertebrate stocks under future climate.

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Bayden D Russell

Full Text Available The future management of commercially exploited species is challenging because techniques used to predict the future distribution of stocks under climate change are currently inadequate. We projected the future distribution and abundance of two commercially harvested abalone species (blacklip abalone, Haliotis rubra and greenlip abalone, H. laevigata inhabiting coastal South Australia, using multiple species distribution models (SDM and for decadal time slices through to 2100. Projections are based on two contrasting global greenhouse gas emissions scenarios. The SDMs identified August (winter Sea Surface Temperature (SST as the best descriptor of abundance and forecast that warming of winter temperatures under both scenarios may be beneficial to both species by allowing increased abundance and expansion into previously uninhabited coasts. This range expansion is unlikely to be realised, however, as projected warming of March SST is projected to exceed temperatures which cause up to 10-fold increases in juvenile mortality. By linking fine-resolution forecasts of sea surface temperature under different climate change scenarios to SDMs and physiological experiments, we provide a practical first approximation of the potential impact of climate-induced change on two species of marine invertebrates in the same fishery.

Abalone Haliotis spp. are in considerable demand worldwide ...

African Journals Online (AJOL)

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AND D-LACTATE, BE USED AS METABOLIC STRESS INDICATORS DURING ... tauropine, is present in high activities (54 U g wet weight-1) in the shell adductor muscle, but ..... BRITZ, P. J. 1996 — Effect of the dietary protein level on growth.

Effect of abalone farming on seawater movement and benthic foraminiferal assemblage of Zostera marina in the inner bay of Wando, South Korea.

Science.gov (United States)

Lee, Yeon Gyu; Choi, Yang Ho; Jeong, Da Un; Lee, Jung Sick; Kim, Yong Wan; Park, Jung Jun; Choi, Jae Ung

2016-08-15

Tidal current survey as well as geochemical and benthic foraminiferal analyses of sediment cores were conducted in an abalone farm and a Zostera bed to understand the degree to which the abalone farm facilities installed along a channel in a shallow sea affect the benthic environment and ecology. In the abalone farm, Ammonia beccarii-Pseudoparrella naraensis-Elphidium somaense-Rosalina globularis-Trochammina hadai and P. naraensis-E. somaense-A. beccarii-T. hadai assemblages appeared owing to an increase in the total nitrogen content from the biodeposits. The Zostera bed consisted of A. beccarii-P. naraensis-Buccella frigida-T. hadai assemblage owing to the gradual expansion of a brackish shallow-water environment by the rapidly decreasing current speed, and it may have flourished. Moreover, the total sulfur, Zn, Cr, and Cu contents in the sediments decreased remarkably more than those of the pre-abalone farming did, caused by the vigorous activity of Zostera marina physiology. Copyright © 2016 Elsevier Ltd. All rights reserved.

Book Review Abalone of the World: Biology, Fisheries and Culture

African Journals Online (AJOL)

several of the more important aspects of abalone biology. One of the most attractive features of the book is the skilful way in which the editors have managed to cover a very broad range of subject material whilst at the same time treating individual topics in sufficient depth to satisfy specialists. The book is divided into nine ...

Use of oil palm kernel meal as a supplement material for abalone mushroom (Pleurotus cystidiosus O.K. Miller cultivation

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Petcharat, V. and

2004-09-01

Full Text Available The objective of this study was to determine the optimum rate of oil palm kernel meal, for an abalone mushroom (Pleurotus cystidiosus cultivation. Different concentrations of oil palm kernel meal (5- 20% were added to pararubber sawdust and used to grow the abalone mushroom in plastic bags. Growth rate of the mycelia, number of days from watering to harvesting and yield were compared to those on 94% sawdust + 5% rice bran + 1% Ca(OH2. The results showed that 10% oil palm kernel meal was the optimum concentration for abalone mushroom cultivation. Yield on 950 g/bag of 89% sawdust + 10% oil palm kernel meal + 1% Ca(OH2 was 202.12 g/bag (B.E. = 60.79% during 120 days of havesting time. Addition of higher concentration of oil palm kernel meal (15-20% did not increase yield of the basidiocarps.

Effects of offshore oil and gas development activities in southern California on larval settlement

International Nuclear Information System (INIS)

Raimondi, P.T.; Barnett, A.; Krause, P.R.

1995-01-01

A series of in situ field experiments were conducted to determine effects of oil and gas drilling activities on the settlement of marine larvae in the deep ocean (180 m). The study sites were a series of three drilling rigs and three reference sites between Pt. Arguello and Pt. Conception in California. Experiments were carried out in both pre-drilling and drilling phases to test the effects of drilling activities (e.g. drilling, drilling mud release, and produced water discharges) on the ability of red abalone (Haliotis rufescens) larvae to settle using an in situ experiment. Their in situ experiment involved reciprocal transplants of settling plates that were ''filmed'' with bacteria from each site. After filming in the field at each of two heights, plates were mounted into chambers, covered with mesh and placed onto recoverable larval arrays for deployment in the field. Before deployment the authors injected approximately 300 competent red abalone larvae into each chamber. One larval array was deployed at each site for three days and each array contained plates filmed at all sites. In addition sterile plates (no surface filming) were included at each site. Upon recovery the number of settled abalone larvae were counted. Therefore, the experiment tested location-related (drilling sites versus reference), waterborne, and height effects on settlement in both the pre-drilling and drilling phases. Their results show that red abalone served as a sensitive indicator for in situ studies of larval settlement. The authors found significantly higher numbers of abalone settling onto plates that were filmed versus those that were not. The authors also found significantly lower settlement rates between the pre-drilling and drilling periods

The steadily increasing demand for South African abalone Haliotis ...

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The usual harvesting method is for a diver to cut all. Ecklonia plants ... This study estimates the biomass of E. maxima available for harvesting, investi- gates the effects of ..... The processes that shape kelp bed structure and dynamics are of ...

A neurotropic herpesvirus infecting the gastropod, abalone, shares ancestry with oyster herpesvirus and a herpesvirus associated with the amphioxus genome

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Sawbridge Tim

2010-11-01

Full Text Available Abstract Background With the exception of the oyster herpesvirus OsHV-1, all herpesviruses characterized thus far infect only vertebrates. Some cause neurological disease in their hosts, while others replicate or become latent in neurological tissues. Recently a new herpesvirus causing ganglioneuritis in abalone, a gastropod, was discovered. Molecular analysis of new herpesviruses, such as this one and others, still to be discovered in invertebrates, will provide insight into the evolution of herpesviruses. Results We sequenced the genome of a neurotropic virus linked to a fatal ganglioneuritis devastating parts of a valuable wild abalone fishery in Australia. We show that the newly identified virus forms part of an ancient clade with its nearest relatives being a herpesvirus infecting bivalves (oyster and, unexpectedly, one we identified, from published data, apparently integrated within the genome of amphioxus, an invertebrate chordate. Predicted protein sequences from the abalone virus genome have significant similarity to several herpesvirus proteins including the DNA packaging ATPase subunit of (putative terminase and DNA polymerase. Conservation of amino acid sequences in the terminase across all herpesviruses and phylogenetic analysis using the DNA polymerase and terminase proteins demonstrate that the herpesviruses infecting the molluscs, oyster and abalone, are distantly related. The terminase and polymerase protein sequences from the putative amphioxus herpesvirus share more sequence similarity with those of the mollusc viruses than with sequences from any of the vertebrate herpesviruses analysed. Conclusions A family of mollusc herpesviruses, Malacoherpesviridae, that was based on a single virus infecting oyster can now be further established by including a distantly related herpesvirus infecting abalone, which, like many vertebrate viruses is neurotropic. The genome of Branchiostoma floridae (amphioxus provides evidence for the

Development of an integrated multi-trophic aquaculture (IMTA system for tropical marine species in southern cebu, Central Philippines

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Danilo B. Largo

2016-05-01

Full Text Available This study presents the establishment of an integrated multi-trophic aquaculture (IMTA system in the tropical open waters of southern Cebu, Philippines using a combination of locally available species, namely donkey’s ear abalone (Haliotis asinina as fed species and seaweeds (Gracilaria heteroclada and Eucheuma denticulatum as inorganic extractive species. The culture of Caulerpa lentillifera as a biofilter did not work in the open sea cultivation system using baskets. Monthly measurements of shell length, width and body weight of the cultured abalones, together with in situ measurements of physicochemical parameters to assess any changes in water quality, mainly nitrate, nitrite, ammonia and phosphate, were conducted over a year period from February 2013 to January 2014 in three designated stations (Abalone, Seaweed and Control Stations at three different depths (surface, middle and bottom.Cage culture of abalone side by side with seaweeds in the open sea did not result in any significant water quality disturbance in the area—at least not in the current volume of caged abalones being used. Of the four inorganic compounds monitored in the field, nitrate and ammonia in the Seaweed Station were shown to have relatively lower year-round average values when compared with the Abalone Station, although in the case of nitrate, it was higher in the Control Station compared with the abalone and Seaweed Stations. Although this difference was not significant, it shows the red seaweeds, G. heteroclada and E. denticulatum, to be functioning as a natural filter for these two nutrients. In contrast, nitrite, and phosphate concentrations were not reduced indicating that the seaweeds were not effective biofilter for these two nutrients.The two-month old hatchery-bred donkey’s ear abalones can grow to a size of 53.8 × 28.2 mm (L × W and body weight of 37.8 g after a period of 12 months. Any expansion of the farm into a much larger commercial

Bio-inspired passive actuator simulating an abalone shell mechanism for structural control

International Nuclear Information System (INIS)

Yang, Henry T Y; Lin, Chun-Hung; Bridges, Daniel; Randall, Connor J; Hansma, Paul K

2010-01-01

An energy dispersion mechanism called 'sacrificial bonds and hidden length', which is found in some biological systems, such as abalone shells and bones, is the inspiration for new strategies for structural control. Sacrificial bonds and hidden length can substantially increase the stiffness and enhance energy dissipation in the constituent molecules of abalone shells and bone. Having been inspired by the usefulness and effectiveness of such a mechanism, which has evolved over millions of years and countless cycles of evolutions, the authors employ the conceptual underpinnings of this mechanism to develop a bio-inspired passive actuator. This paper presents a fundamental method for optimally designing such bio-inspired passive actuators for structural control. To optimize the bio-inspired passive actuator, a simple method utilizing the force–displacement–velocity (FDV) plots based on LQR control is proposed. A linear regression approach is adopted in this research to find the initial values of the desired parameters for the bio-inspired passive actuator. The illustrative examples, conducted by numerical simulation with experimental validation, suggest that the bio-inspired passive actuator based on sacrificial bonds and hidden length may be comparable in performance to state-of-the-art semi-active actuators

Bio-inspired passive actuator simulating an abalone shell mechanism for structural control

Science.gov (United States)

Yang, Henry T. Y.; Lin, Chun-Hung; Bridges, Daniel; Randall, Connor J.; Hansma, Paul K.

2010-10-01

An energy dispersion mechanism called 'sacrificial bonds and hidden length', which is found in some biological systems, such as abalone shells and bones, is the inspiration for new strategies for structural control. Sacrificial bonds and hidden length can substantially increase the stiffness and enhance energy dissipation in the constituent molecules of abalone shells and bone. Having been inspired by the usefulness and effectiveness of such a mechanism, which has evolved over millions of years and countless cycles of evolutions, the authors employ the conceptual underpinnings of this mechanism to develop a bio-inspired passive actuator. This paper presents a fundamental method for optimally designing such bio-inspired passive actuators for structural control. To optimize the bio-inspired passive actuator, a simple method utilizing the force-displacement-velocity (FDV) plots based on LQR control is proposed. A linear regression approach is adopted in this research to find the initial values of the desired parameters for the bio-inspired passive actuator. The illustrative examples, conducted by numerical simulation with experimental validation, suggest that the bio-inspired passive actuator based on sacrificial bonds and hidden length may be comparable in performance to state-of-the-art semi-active actuators.

Modification of calcite crystal growth by abalone shell proteins: an atomic force microscope study.

OpenAIRE

Walters, D A; Smith, B L; Belcher, A M; Paloczi, G T; Stucky, G D; Morse, D E; Hansma, P K

1997-01-01

A family of soluble proteins from the shell of Haliotis rufescens was introduced over a growing calcite crystal being scanned in situ by an atomic force microscope (AFM). Atomic step edges on the crystal surface were altered in shape and speed of growth by the proteins. Proteins attached nonuniformly to the surface, indicating different interactions with crystallographically different step edges. The observed changes were consistent with the habit modification induced by this family of protei...

Disk

NARCIS (Netherlands)

P.A. Boncz (Peter); L. Liu (Lei); M. Tamer Özsu

2008-01-01

htmlabstractIn disk storage, data is recorded on planar, round and rotating surfaces (disks, discs, or platters). A disk drive is a peripheral device of a computer system, connected by some communication medium to a disk controller. The disk controller is a chip, typically connected to the CPU of

Concentration of radioactive cobalt by seaweeds in the food chain

International Nuclear Information System (INIS)

Nakahara, Motokazu; Koyanagi, Taku; Saiki, Masamichi

1976-01-01

On the pathway of radioactive substances in marine environments, seaweeds play an important role because of their higher concentration factors for many radionuclides and because they constitute a link of food chain in the sea. In the present work, uptake, distribution and excretion of radioactive cobalt were studied on several kinds of seaweeds by radioisotope tracer experiments under laboratory conditions and concentration factors were calculated. The concentration factors were also estimated from the results of stable cobalt determination by activation analysis or atomic absorption spectrometry on seaweeds and seawater, and compared with the results of tracer expts. The seaweeds showed the species specificity for the concentration of stable and radioactive cobalt with diverse values of concentration factors and biological half-lives. The transfer of radioactive cobalt in the food chain from contaminated seaweeds to mollusca was examined by feeding abalones, Haliotis discus, with four kinds of seaweed labelled with 60 Co and observing retention. Absorption rate for radioactive cobalt by abalones calculated at two days after feeding showed diverse values depending upon the species of seaweed, as follows: 47% through Laminaria japonica and Ulva pertusa, 31% through Undaria pinnatifida and 26 through Eisenia bicyclis, respectively. From the results, it was assumed that the accumulation of radioactive cobalt by mollusca is affected by the species of seaweeds as food. A very high concentration of ingested radioactive cobalt in the midgut gland was seen on the autoradiograph of abalone samples. (auth.)

Concentration of radioactive cobalt by seaweeds in the food chain

International Nuclear Information System (INIS)

Nakahara, M.; Koyanagi, T.; Saiki, M.

1975-01-01

On the pathway of radioactive substances in marine environments, seaweeds play an important role because of their higher concentration factors for many radionuclides and because they constitute a link in the food chain. In the present work, uptake, distribution and excretion of radioactive cobalt were studied on several kinds of seaweeds by radioisotope tracer experiments under laboratory conditions and concentration factors were calculated. The concentration factors were also estimated from the results of stable cobalt determination by activation analysis or atomic absorption spectrometry on seaweeds and seawater, and compared with the results of tracer experiments. The seaweeds showed the species specificity for the concentration of stable and radioactive cobalt with diverse values of concentration factors and biological half-lives. The transfer of radioactive cobalt in the food chain from contaminated seaweeds to mollusca was examined by feeding abalones, Haliotis discus, with four kinds of seaweed labelled with 60 Co and observing retention. Absorption rate for radioactive cobalt by abalones calculated at two days after feeding showed diverse values depending upon the species of seaweed, as follows: 47% through Laminaria japonica and Ulva pertusa, 31% through Undaria pinnatifida and 26% through Eisenia bicyclis, respectively. From the results, it was assumed that the accumulation of radioactive cobalt by mollusca is affected by the species of seaweeds as food. A very high concentration of ingested radioactive cobalt in the midgut gland was seen on the autoradiograph of abalone samples. (author)

Species Profiles. Life Histories and Environmental Requirements of Coastal Fishes and Invertebrates (Pacific Southwest). BLACK, GREEN, and RED ABALONES.

Science.gov (United States)

1985-03-01

Pterygophora cal i fornica Division Rhodophyta Division Rhodophyta (Red algae) (Red algae) Gelidium sp. Botryoglossum farlowianum Gigartina sp. Gigartina sp...example, the more green abalone strongly prefers the red resilient, denser algae are eaten at a algae Gelidium , Pterocladia, Ploca- slower rate than

78 FR 69033 - Endangered and Threatened Wildlife; 90-Day Finding on Petitions To List the Pinto Abalone as...

Science.gov (United States)

2013-11-18

... Petitions To List the Pinto Abalone as Threatened or Endangered Under the Endangered Species Act AGENCY... kamtschatkana) as a threatened or endangered species under the Endangered Species Act (ESA) and to designate... recommendation by NatureServe for listing under the U.S. Endangered Species Act'' because NatureServe assessments...

Initial characterization of receptors for molecules that induce the settlement and metamorphosis of Haliotis rufescens larvae

International Nuclear Information System (INIS)

Trapido-Rosenthal, H.G.

1985-01-01

Larvae of the marine gastropod mollusc Haliotis refescens are induced to undergo metamorphosis by γ-aminobutyric acid (GABA) and stereochemically related compounds. The most potent of these inducers is (-)-β-(parachlorophenyl)-GABA (baclofen). The inductive response exhibits positive cooperatively, and is subject to both facilitation (up-regulation) and habituation (down-regulation). Facilitation is brought about by diamino acids such as L-diaminopropionic acid (L-DAPA), and is characterized by decreased Hill coefficients (n/sub H/) and concentration requirements (EC 50 ) for inducers. Facilitation does not require the simultaneous presence of facilitating and inducing compounds, and the facilitated state is persistent. Larvae are capable of being up-regulated 2 days before they are capable of undergoing settlement and metamorphosis. Habituation can be brought about by exposure of pre-competent larvae to GABA 4 days prior to the attainment of competence; it is then slowly reversible. Larvae specifically bind tritiated (-)-baclofen in a manner that is saturable with both increasing time of exposure of larvae to, and with increasing concentration of, this compound. Specific binding can be competed for by unlabeled GABA-mimetic inducing molecules; the order of effectiveness of these molecules as competitors for specific binding correlates well with their effectiveness as inducers of metamorphosis. Facilitation of larvae by exposure to diamino acids does not alter their specific binding of tritiated (-)-baclofen. It is concluded from these findings that Haliotis larvae possess receptors for GABA-mimetic compounds

Identifying Likely Disk-hosting M dwarfs with Disk Detective

Science.gov (United States)

Silverberg, Steven; Wisniewski, John; Kuchner, Marc J.; Disk Detective Collaboration

2018-01-01

M dwarfs are critical targets for exoplanet searches. Debris disks often provide key information as to the formation and evolution of planetary systems around higher-mass stars, alongside the planet themselves. However, less than 300 M dwarf debris disks are known, despite M dwarfs making up 70% of the local neighborhood. The Disk Detective citizen science project has identified over 6000 new potential disk host stars from the AllWISE catalog over the past three years. Here, we present preliminary results of our search for new disk-hosting M dwarfs in the survey. Based on near-infrared color cuts and fitting stellar models to photometry, we have identified over 500 potential new M dwarf disk hosts, nearly doubling the known number of such systems. In this talk, we present our methodology, and outline our ongoing work to confirm systems as M dwarf disks.

ALMA Survey of Lupus Protoplanetary Disks. II. Gas Disk Radii

Science.gov (United States)

Ansdell, M.; Williams, J. P.; Trapman, L.; van Terwisga, S. E.; Facchini, S.; Manara, C. F.; van der Marel, N.; Miotello, A.; Tazzari, M.; Hogerheijde, M.; Guidi, G.; Testi, L.; van Dishoeck, E. F.

2018-05-01

We present Atacama Large Millimeter/Sub-Millimeter Array (ALMA) Band 6 observations of a complete sample of protoplanetary disks in the young (∼1–3 Myr) Lupus star-forming region, covering the 1.33 mm continuum and the 12CO, 13CO, and C18O J = 2–1 lines. The spatial resolution is ∼0.″25 with a medium 3σ continuum sensitivity of 0.30 mJy, corresponding to M dust ∼ 0.2 M ⊕. We apply Keplerian masking to enhance the signal-to-noise ratios of our 12CO zero-moment maps, enabling measurements of gas disk radii for 22 Lupus disks; we find that gas disks are universally larger than millimeter dust disks by a factor of two on average, likely due to a combination of the optically thick gas emission and the growth and inward drift of the dust. Using the gas disk radii, we calculate the dimensionless viscosity parameter, α visc, finding a broad distribution and no correlations with other disk or stellar parameters, suggesting that viscous processes have not yet established quasi-steady states in Lupus disks. By combining our 1.33 mm continuum fluxes with our previous 890 μm continuum observations, we also calculate the millimeter spectral index, α mm, for 70 Lupus disks; we find an anticorrelation between α mm and millimeter flux for low-mass disks (M dust ≲ 5), followed by a flattening as disks approach α mm ≈ 2, which could indicate faster grain growth in higher-mass disks, but may also reflect their larger optically thick components. In sum, this work demonstrates the continuous stream of new insights into disk evolution and planet formation that can be gleaned from unbiased ALMA disk surveys.

THICK-DISK EVOLUTION INDUCED BY THE GROWTH OF AN EMBEDDED THIN DISK

International Nuclear Information System (INIS)

Villalobos, Alvaro; Helmi, Amina; Kazantzidis, Stelios

2010-01-01

We perform collisionless N-body simulations to investigate the evolution of the structural and kinematical properties of simulated thick disks induced by the growth of an embedded thin disk. The thick disks used in the present study originate from cosmologically common 5:1 encounters between initially thin primary disk galaxies and infalling satellites. The growing thin disks are modeled as static gravitational potentials and we explore a variety of growing-disk parameters that are likely to influence the response of thick disks. We find that the final thick-disk properties depend strongly on the total mass and radial scale length of the growing thin disk, and much less sensitively on its growth timescale and vertical scale height as well as the initial sense of thick-disk rotation. Overall, the growth of an embedded thin disk can cause a substantial contraction in both the radial and vertical direction, resulting in a significant decrease in the scale lengths and scale heights of thick disks. Kinematically, a growing thin disk can induce a notable increase in the mean rotation and velocity dispersions of thick-disk stars. We conclude that the reformation of a thin disk via gas accretion may play a significant role in setting the structure and kinematics of thick disks, and thus it is an important ingredient in models of thick-disk formation.

Oscillations of disks

CERN Document Server

Kato, Shoji

2016-01-01

This book presents the current state of research on disk oscillation theory, focusing on relativistic disks and tidally deformed disks. Since the launch of the Rossi X-ray Timing Explorer (RXTE) in 1996, many high-frequency quasiperiodic oscillations (HFQPOs) have been observed in X-ray binaries. Subsequently, similar quasi-periodic oscillations have been found in such relativistic objects as microquasars, ultra-luminous X-ray sources, and galactic nuclei. One of the most promising explanations of their origin is based on oscillations in relativistic disks, and a new field called discoseismology is currently developing. After reviewing observational aspects, the book presents the basic characteristics of disk oscillations, especially focusing on those in relativistic disks. Relativistic disks are essentially different from Newtonian disks in terms of several basic characteristics of their disk oscillations, including the radial distributions of epicyclic frequencies. In order to understand the basic processes...

Magnetically Induced Disk Winds and Transport in the HL Tau Disk

International Nuclear Information System (INIS)

Hasegawa, Yasuhiro; Flock, Mario; Turner, Neal J.; Okuzumi, Satoshi

2017-01-01

The mechanism of angular momentum transport in protoplanetary disks is fundamental to understanding the distributions of gas and dust in the disks. The unprecedented ALMA observations taken toward HL Tau at high spatial resolution and subsequent radiative transfer modeling reveal that a high degree of dust settling is currently achieved in the outer part of the HL Tau disk. Previous observations, however, suggest a high disk accretion rate onto the central star. This configuration is not necessarily intuitive in the framework of the conventional viscous disk model, since efficient accretion generally requires a high level of turbulence, which can suppress dust settling considerably. We develop a simplified, semi-analytical disk model to examine under what condition these two properties can be realized in a single model. Recent, non-ideal MHD simulations are utilized to realistically model the angular momentum transport both radially via MHD turbulence and vertically via magnetically induced disk winds. We find that the HL Tau disk configuration can be reproduced well when disk winds are properly taken into account. While the resulting disk properties are likely consistent with other observational results, such an ideal situation can be established only if the plasma β at the disk midplane is β 0 ≃ 2 × 10 4 under the assumption of steady accretion. Equivalently, the vertical magnetic flux at 100 au is about 0.2 mG. More detailed modeling is needed to fully identify the origin of the disk accretion and quantitatively examine plausible mechanisms behind the observed gap structures in the HL Tau disk.

Magnetically Induced Disk Winds and Transport in the HL Tau Disk

Energy Technology Data Exchange (ETDEWEB)

Hasegawa, Yasuhiro; Flock, Mario; Turner, Neal J. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Okuzumi, Satoshi, E-mail: yasuhiro@caltech.edu [Department of Earth and Planetary Sciences, Tokyo Institute of Technology, Meguro-ku, Tokyo 152-8551 (Japan)

2017-08-10

The mechanism of angular momentum transport in protoplanetary disks is fundamental to understanding the distributions of gas and dust in the disks. The unprecedented ALMA observations taken toward HL Tau at high spatial resolution and subsequent radiative transfer modeling reveal that a high degree of dust settling is currently achieved in the outer part of the HL Tau disk. Previous observations, however, suggest a high disk accretion rate onto the central star. This configuration is not necessarily intuitive in the framework of the conventional viscous disk model, since efficient accretion generally requires a high level of turbulence, which can suppress dust settling considerably. We develop a simplified, semi-analytical disk model to examine under what condition these two properties can be realized in a single model. Recent, non-ideal MHD simulations are utilized to realistically model the angular momentum transport both radially via MHD turbulence and vertically via magnetically induced disk winds. We find that the HL Tau disk configuration can be reproduced well when disk winds are properly taken into account. While the resulting disk properties are likely consistent with other observational results, such an ideal situation can be established only if the plasma β at the disk midplane is β {sub 0} ≃ 2 × 10{sup 4} under the assumption of steady accretion. Equivalently, the vertical magnetic flux at 100 au is about 0.2 mG. More detailed modeling is needed to fully identify the origin of the disk accretion and quantitatively examine plausible mechanisms behind the observed gap structures in the HL Tau disk.

Variations of 210Po and 210Pb in various marine organisms from Western English Channel: contribution of 210Po to the radiation dose

International Nuclear Information System (INIS)

Connan, O.; Germain, P.; Solier, L.; Gouret, G.

2007-01-01

Measurements of 210 Po were carried out in various marine matrices (mussels, oysters, seaweed, fish, and abalones) and in seawater at several points along the French coast, over a period of 2 years (2003-2005). These measurements contribute to a better knowledge of this element, since few recent data exist for the French coast. Marked seasonal variations have been revealed in some species and there are differences according to the way of life of these species. Activities in mussels (Mytilus edulis) and oysters (Crassostrea gigas) are similar and varying between 90 and 600 Bq kg -1 (d.w.). Activities in macroalgae (Fucus serratus) are lowest, between 4 and 16 Bq kg -1 (d.w.). In oyster, abalone (Haliotis tuberculata) and fish (Solea solea, Sparus sp.), the strongest activities are measured in the digestive glands, the gills and the gonads. 210 Po/ 210 Pb ratios in all cases have values of more than one for all species. From a significant number of measurements, CFs were calculated for seaweed (between 4.6 x 10 3 and 5.0 x 10 3 ) and for molluscs, with highest CFs (>10 5 ) found for the digestive gland and gills of the oysters, the digestive gland of the abalones and the liver of fish. Finally, the activities measured have made it possible to estimate the internal dose from chronic exposure due to 210 Po received by the marine organisms (0.05 μG h -1 for macroalgae, between 0.70 and 1.5 μG h -1 for mussels and oyster), and the contribution of seafood to the dose received by humans (46-129 μSv y -1 )

Catalytically important amino-acid residues of abalone alginate lyase HdAly assessed by site-directed mutagenesis

OpenAIRE

Yamamoto, Sayo; Sahara, Takehiko; Sato, Daisuke; Kawasaki, Kosei; Ohgiya, Satoru; Inoue, Akira; Ojima, Takao

2008-01-01

Alginate lyase is an enzyme that degrades alginate chains via β-elimination and has been used for the production of alginate oligosaccharides and protoplasts from brown algae. Previously, we deduced the amino-acid sequence of an abalone alginate lyase, HdAly, from its cDNA sequence and, through multiple amino-acid sequence alignment, found that several basic amino-acid residues were highly conserved among the polysaccharide-lyase family 14 (PL-14) enzymes including HdAly. In the present study...

Contact statuses between functionally graded brake disk and pure pad disk

International Nuclear Information System (INIS)

Shahzamanian, M.M.; Sahari, B.B.; Bayat, M.; Mustapha, F.; Ismarrubie, Z.N.; Shahrjerdi, A.

2009-01-01

Full text: The contact statuses between functionally graded (FG) brake disks and pure pad disk are investigated by using finite element method (FEM). Two types of variation is considered for FG brake disk, the variation of materials are considered change in radial and thickness direction of disk. The material properties of these two types of FG brake disks are assumed to be represented by power-law distributions in the radius and thickness direction. The results are obtained and then compared. For the radial FG brake disk, the inner and outer surfaces are considered metal and ceramic respectively, and friction coefficient between metal surface and ceramic surface of FG brake dick with pad are considered 1.4 and 0.75 respectively. For the thickness FG brake disk the contact surface with pure pad brake disk is ceramic and the free surface is metal and friction coefficient between ceramic (contact) surface and pure pad brake disk is considered 0.75. In both types of FG brake disks the Coulomb contact friction is applied. Mechanical response of FG brake disks are compared and verified with the known results in the literatures. Three types of contact statuses are introduced as Sticking, Contact and Near Contact. The contact status between pad and disk for different values for pad thickness, grading index,n , and percentage of friction coefficient (λ) is shown. It can be seen that for all values of percentage of friction coefficient,λ , and grading indices, n, by increasing the thickness of pad cause the contact status changes from sticking to contact and then to near contact. (author)

GIANT PLANET MIGRATION, DISK EVOLUTION, AND THE ORIGIN OF TRANSITIONAL DISKS

International Nuclear Information System (INIS)

Alexander, Richard D.; Armitage, Philip J.

2009-01-01

We present models of giant planet migration in evolving protoplanetary disks. Our disks evolve subject to viscous transport of angular momentum and photoevaporation, while planets undergo Type II migration. We use a Monte Carlo approach, running large numbers of models with a range in initial conditions. We find that relatively simple models can reproduce both the observed radial distribution of extrasolar giant planets, and the lifetimes and accretion histories of protoplanetary disks. The use of state-of-the-art photoevaporation models results in a degree of coupling between planet formation and disk clearing, which has not been found previously. Some accretion across planetary orbits is necessary if planets are to survive at radii ∼<1.5 AU, and if planets of Jupiter mass or greater are to survive in our models they must be able to form at late times, when the disk surface density in the formation region is low. Our model forms two different types of 'transitional' disks, embedded planets and clearing disks, which show markedly different properties. We find that the observable properties of these systems are broadly consistent with current observations, and highlight useful observational diagnostics. We predict that young transition disks are more likely to contain embedded giant planets, while older transition disks are more likely to be undergoing disk clearing.

CT-guided percutaneous laser disk decompression for cervical and lumbar disk hernia

International Nuclear Information System (INIS)

Shimizu, Kanichiro; Koyama, Tutomu; Harada, Junta; Abe, Toshiaki

2008-01-01

Percutaneous laser disk decompression under X-ray fluoroscopy was first reported in 1987 for minimally invasive therapy of lumbar disk hernia. In patients with disk hernia, laser vaporizes a small portion of the intervertebral disk thereby reducing the volume and pressure of the affected disk. We present the efficacy and safety of this procedure, and analysis of fair or poor response cases. In our study, 226 cases of lumbar disk hernia and 7 cases of cervical disk hernia were treated under CT guided PLDD. Japan Orthopedic Association (JOA) score and Mac-Nab criteria were investigated to evaluate the response to treatment. Improvement ratio based on the JOA score was calculated as follows. Overall success rate was 91.6% in cases lumber disk hernia, and 100% in cases of cervical disk hernia. We experienced two cases with two cases with postoperative complication. Both cases were treated conservatively. The majority of acute cases and post operative cases were reported to be 'good' on Mac-Nab criteria. Cases of fair or poor response on Mac-Nab criteria were lateral type, foraminal stenosis or large disk hernia. CT-guided PLDD is a safe and accurate procedure. The overall success rate can be increased by carefully selecting patients. (author)

Disk Storage Server

CERN Multimedia

This model was a disk storage server used in the Data Centre up until 2012. Each tray contains a hard disk drive (see the 5TB hard disk drive on the main disk display section - this actually fits into one of the trays). There are 16 trays in all per server. There are hundreds of these servers mounted on racks in the Data Centre, as can be seen.

The inventory of mollusc species and its potent on seagrass bed in Kei Kecil Islands, Southeast Moluccas

Directory of Open Access Journals (Sweden)

AGUS KUSNADI

2008-10-01

Full Text Available Inventory of mollusk species and its potential on sea grass bed in Kei Kecil islands, Southeast Moluccas have been conducted by using quadrate-transect line method. The study was carried out in February-August 2007. There were 103 species of mollusk observed, 80 species belong to gastropods and 23 belong to bivalves. From the total species, 72 of them were reported as the potential species and the others still unknown. Most of potential group was used as food resources (55 species and other species were potential as decoration, souvenir, ornament, and accessories (31 species. Some species were potential for building material, knife tool, barter tool and bioactive compounds. The top shells (Trochus niloticus, the giant clams (Tridacna spp. and Hippopus hippopus and the abalone (Haliotis spp. were the major trading commodities for shellfish fisheries.

HNC IN PROTOPLANETARY DISKS

International Nuclear Information System (INIS)

Graninger, Dawn; Öberg, Karin I.; Qi, Chunhua; Kastner, Joel

2015-01-01

The distributions and abundances of small organics in protoplanetary disks are potentially powerful probes of disk physics and chemistry. HNC is a common probe of dense interstellar regions and the target of this study. We use the Submillimeter Array (SMA) to observe HNC 3–2 toward the protoplanetary disks around the T Tauri star TW Hya and the Herbig Ae star HD 163296. HNC is detected toward both disks, constituting the first spatially resolved observations of HNC in disks. We also present SMA observations of HCN 3–2 and IRAM 30 m observations of HCN and HNC 1–0 toward HD 163296. The disk-averaged HNC/HCN emission ratio is 0.1–0.2 toward both disks. Toward TW Hya, the HNC emission is confined to a ring. The varying HNC abundance in the TW Hya disk demonstrates that HNC chemistry is strongly linked to the disk physical structure. In particular, the inner rim of the HNC ring can be explained by efficient destruction of HNC at elevated temperatures, similar to what is observed in the ISM. However, to realize the full potential of HNC as a disk tracer requires a combination of high SNR spatially resolved observations of HNC and HCN and disk-specific HNC chemical modeling

HNC IN PROTOPLANETARY DISKS

Energy Technology Data Exchange (ETDEWEB)

Graninger, Dawn; Öberg, Karin I.; Qi, Chunhua [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Kastner, Joel, E-mail: dgraninger@cfa.harvard.edu [Center for Imaging Science, School of Physics and Astronomy, and Laboratory for Multiwavelength Astrophysics, Rochester Institute of Technology, 54 Lomb Memorial Drive, Rochester, NY 14623 (United States)

2015-07-01

The distributions and abundances of small organics in protoplanetary disks are potentially powerful probes of disk physics and chemistry. HNC is a common probe of dense interstellar regions and the target of this study. We use the Submillimeter Array (SMA) to observe HNC 3–2 toward the protoplanetary disks around the T Tauri star TW Hya and the Herbig Ae star HD 163296. HNC is detected toward both disks, constituting the first spatially resolved observations of HNC in disks. We also present SMA observations of HCN 3–2 and IRAM 30 m observations of HCN and HNC 1–0 toward HD 163296. The disk-averaged HNC/HCN emission ratio is 0.1–0.2 toward both disks. Toward TW Hya, the HNC emission is confined to a ring. The varying HNC abundance in the TW Hya disk demonstrates that HNC chemistry is strongly linked to the disk physical structure. In particular, the inner rim of the HNC ring can be explained by efficient destruction of HNC at elevated temperatures, similar to what is observed in the ISM. However, to realize the full potential of HNC as a disk tracer requires a combination of high SNR spatially resolved observations of HNC and HCN and disk-specific HNC chemical modeling.

Development of Disk Rover, wall-climbing robot using permanent magnet disk

International Nuclear Information System (INIS)

Hirose, Shigeo; Tsutsumitake; Hiroshi; Toyama, Ryousei; Kobayashi, Kengo.

1992-01-01

A new type of wall climbing robot, named Disk Rover, using permanent magnet disks are developed. The newly introduced permanent magnet disk is to rotate the magnet disk on the surface of wall with partly contacted posture. It allows to produce high magnetic attraction force compared with conventional permanent wheel which utilizes only a small portion of the magnet installed around the wheel. The optimum design of the magnetic wheel is done by using finit element method and it is shown that the magnetic attraction force vs. weight ratio can be designed about three times higher than conventional type magnet wheel. The developed Disk Rover is 25 kg in weight including controller and battery, about 685 mm in diameter, 239 mm in height and has a pair of permanent magnet disks. It is demonstrated by the experiments that the Disk Rover can move around on the surface of the wall quite smoothly by radio control and has payload of about its own weight. Several considerations are also done in order to surmount bead weld. (author)

Variations of {sup 210}Po and {sup 210}Pb in various marine organisms from Western English Channel: contribution of {sup 210}Po to the radiation dose

Energy Technology Data Exchange (ETDEWEB)

Connan, O. [Institut de Radioprotection et de Surete Nucleaire, Laboratoire de Radioecologie de Cherbourg-Octeville, IRSN/DEI/SECRE/LRC, Rue Max Pol Fouchet, 50130 Cherbourg-Octeville (France)], E-mail: olivier.connan@irsn.fr; Germain, P.; Solier, L.; Gouret, G. [Institut de Radioprotection et de Surete Nucleaire, Laboratoire de Radioecologie de Cherbourg-Octeville, IRSN/DEI/SECRE/LRC, Rue Max Pol Fouchet, 50130 Cherbourg-Octeville (France)

2007-10-15

Measurements of {sup 210}Po were carried out in various marine matrices (mussels, oysters, seaweed, fish, and abalones) and in seawater at several points along the French coast, over a period of 2 years (2003-2005). These measurements contribute to a better knowledge of this element, since few recent data exist for the French coast. Marked seasonal variations have been revealed in some species and there are differences according to the way of life of these species. Activities in mussels (Mytilus edulis) and oysters (Crassostrea gigas) are similar and varying between 90 and 600 Bq kg{sup -1} (d.w.). Activities in macroalgae (Fucus serratus) are lowest, between 4 and 16 Bq kg{sup -1} (d.w.). In oyster, abalone (Haliotis tuberculata) and fish (Solea solea, Sparus sp.), the strongest activities are measured in the digestive glands, the gills and the gonads. {sup 210}Po/{sup 210}Pb ratios in all cases have values of more than one for all species. From a significant number of measurements, CFs were calculated for seaweed (between 4.6 x 10{sup 3} and 5.0 x 10{sup 3}) and for molluscs, with highest CFs (>10{sup 5}) found for the digestive gland and gills of the oysters, the digestive gland of the abalones and the liver of fish. Finally, the activities measured have made it possible to estimate the internal dose from chronic exposure due to {sup 210}Po received by the marine organisms (0.05 {mu}G h{sup -1} for macroalgae, between 0.70 and 1.5 {mu}G h{sup -1} for mussels and oyster), and the contribution of seafood to the dose received by humans (46-129 {mu}Sv y{sup -1})

Understanding Floppy Disks.

Science.gov (United States)

Valentine, Pamela

1980-01-01

The author describes the floppy disk with an analogy to the phonograph record, and discusses the advantages, disadvantages, and capabilities of hard-sectored and soft-sectored floppy disks. She concludes that, at present, the floppy disk will continue to be the primary choice of personal computer manufacturers and their customers. (KC)

OT1_ipascucc_1: Understanding the Origin of Transition Disks via Disk Mass Measurements

Science.gov (United States)

Pascucci, I.

2010-07-01

Transition disks are a distinguished group of few Myr-old systems caught in the phase of dispersing their inner dust disk. Three different processes have been proposed to explain this inside-out clearing: grain growth, photoevaporation driven by the central star, and dynamical clearing by a forming giant planet. Which of these processes lead to a transition disk? Distinguishing between them requires the combined knowledge of stellar accretion rates and disk masses. We propose here to use 43.8 hours of PACS spectroscopy to detect the [OI] 63 micron emission line from a sample of 21 well-known transition disks with measured mass accretion rates. We will use this line, in combination with ancillary CO millimeter lines, to measure their gas disk mass. Because gas dominates the mass of protoplanetary disks our approach and choice of lines will enable us to trace the bulk of the disk mass that resides beyond tens of AU from young stars. Our program will quadruple the number of transition disks currently observed with Herschel in this setting and for which disk masses can be measured. We will then place the transition and the ~100 classical/non-transition disks of similar age (from the Herschel KP "Gas in Protoplanetary Systems") in the mass accretion rate-disk mass diagram with two main goals: 1) reveal which gaps have been created by grain growth, photoevaporation, or giant planet formation and 2) from the statistics, determine the main disk dispersal mechanism leading to a transition disk.

Exploring Disks Around Planets

Science.gov (United States)

Kohler, Susanna

2017-07-01

Giant planets are thought to form in circumstellar disks surrounding young stars, but material may also accrete into a smaller disk around the planet. Weve never detected one of these circumplanetary disks before but thanks to new simulations, we now have a better idea of what to look for.Image from previous work simulating a Jupiter-mass planet forming inside a circumstellar disk. The planet has its own circumplanetary disk of accreted material. [Frdric Masset]Elusive DisksIn the formation of giant planets, we think the final phase consists of accretion onto the planet from a disk that surrounds it. This circumplanetary disk is important to understand, since it both regulates the late gas accretion and forms the birthplace of future satellites of the planet.Weve yet to detect a circumplanetary disk thus far, because the resolution needed to spot one has been out of reach. Now, however, were entering an era where the disk and its kinematics may be observable with high-powered telescopes (like the Atacama Large Millimeter Array).To prepare for such observations, we need models that predict the basic characteristics of these disks like the mass, temperature, and kinematic properties. Now a researcher at the ETH Zrich Institute for Astronomy in Switzerland, Judit Szulgyi, has worked toward this goal.Simulating CoolingSzulgyi performs a series of 3D global radiative hydrodynamic simulations of 1, 3, 5, and 10 Jupiter-mass (MJ) giant planets and their surrounding circumplanetary disks, embedded within the larger circumstellar disk around the central star.Density (left column), temperature (center), and normalized angular momentum (right) for a 1 MJ planet over temperatures cooling from 10,000 K (top) to 1,000 K (bottom). At high temperatures, a spherical circumplanetary envelope surrounds the planet, but as the planet cools, the envelope transitions around 64,000 K to a flattened disk. [Szulgyi 2017]This work explores the effects of different planet temperatures and

Equilibrium configuration of a stratus floating above accretion disks: Full-disk calculation

Science.gov (United States)

Itanishi, Yusuke; Fukue, Jun

2017-06-01

We examine floating strati above a luminous accretion disk, supported by the radiative force from the entire disk, and calculate the equilibrium locus, which depends on the disk luminosity and the optical depth of the stratus. Due to the radiative transfer effect (albedo effect), the floating height of the stratus with a finite optical depth generally becomes high, compared with the particle case. In contrast to the case of the near-disk approximation, moreover, the floating height becomes yet higher in the present full-disk calculation, since the intense radiation from the inner disk is taken into account. As a result, when the disk luminosity normalized by the Eddington luminosity is ˜0.3 and the stratus optical depth is around unity, the stable configuration disappears at around r ˜ 50 rg, rg being the Schwarzschild radius, and the stratus would be blown off as a cloudy wind consisting of many strati with appropriate conditions. This luminosity is sufficiently smaller than the Eddington one, and the present results suggest that the radiation-driven cloudy wind can be easily blown off from the sub-Eddington disk, and this can explain various outflows observed in ultra-fast outflow objects as well as in broad-absorption-line quasars.

2TB hard disk drive

CERN Multimedia

This particular object was used up until 2012 in the Data Centre. It slots into one of the Disk Server trays. Hard disks were invented in the 1950s. They started as large disks up to 20 inches in diameter holding just a few megabytes (link is external). They were originally called "fixed disks" or "Winchesters" (a code name used for a popular IBM product). They later became known as "hard disks" to distinguish them from "floppy disks (link is external)." Hard disks have a hard platter that holds the magnetic medium, as opposed to the flexible plastic film found in tapes and floppies.

Crystal orientations in nacreous layers of organic-inorganic biocomposites

Energy Technology Data Exchange (ETDEWEB)

Lee, Seung Woo, E-mail: jacklee@kaist.ac.kr [Department of Chemical and Biomolecular Engineering, KAIST, Daejeon (Korea, Republic of)

2009-09-15

Abalone shell comprises a bio-composite material, combining the properties of inorganic calcite intergrown with organic nacre. This paper reports about the microstructure of this composite. By examining the Kikuchi patterns obtained for nacre (Haliotis discus hannai) using transmission electron microscopy, we have shown that the tiles within nacre have specific orientations. The stereographic projection spheres for the tiles of nacre can be divided into two main types, namely a right oriented region and a left oriented region with respect to the c axis as a reference plane (001). The cluster character of nacre can be explained in terms of the growth mechanism of the 'Christmas tree' pattern. The orientation of the c-axis in the nacreous layer is elucidated for the first time. We demonstrate the use of the soluble protein obtained from the tiles of nacre in in vitro calcium carbonate crystallization.

Crystal orientations in nacreous layers of organic-inorganic biocomposites

International Nuclear Information System (INIS)

Lee, Seung Woo

2009-01-01

Abalone shell comprises a bio-composite material, combining the properties of inorganic calcite intergrown with organic nacre. This paper reports about the microstructure of this composite. By examining the Kikuchi patterns obtained for nacre (Haliotis discus hannai) using transmission electron microscopy, we have shown that the tiles within nacre have specific orientations. The stereographic projection spheres for the tiles of nacre can be divided into two main types, namely a right oriented region and a left oriented region with respect to the c axis as a reference plane (001). The cluster character of nacre can be explained in terms of the growth mechanism of the 'Christmas tree' pattern. The orientation of the c-axis in the nacreous layer is elucidated for the first time. We demonstrate the use of the soluble protein obtained from the tiles of nacre in in vitro calcium carbonate crystallization.

DISK DETECTIVE: DISCOVERY OF NEW CIRCUMSTELLAR DISK CANDIDATES THROUGH CITIZEN SCIENCE

Energy Technology Data Exchange (ETDEWEB)

Kuchner, Marc J.; McElwain, Michael; Padgett, Deborah L. [NASA Goddard Space Flight Center Exoplanets and Stellar Astrophysics Laboratory, Code 667 Greenbelt, MD 21230 (United States); Silverberg, Steven M.; Wisniewski, John P. [Homer L. Dodge Department of Physics and Astronomy The University of Oklahoma 440 W. Brooks St. Norman, OK 73019 (United States); Bans, Alissa S. [Valparaiso University, Department of Physics and Astronomy, Neils Science Center, 1610 Campus Drive East, Valparaiso, IN 46383 (United States); Bhattacharjee, Shambo [International Space University 1 Rue Jean-Dominique Cassini F-67400 Illkirch-Graffenstaden (France); Kenyon, Scott J. [Smithsonian Astrophysical Observatory 60 Garden Street Cambridge, MA 02138 (United States); Debes, John H. [Space Telescope Science Institute 3700 San Martin Dr. Baltimore, MD 21218 (United States); Currie, Thayne [National Astronomical Observatory of Japan 650 N A’ohokhu Place Hilo, HI 96720 (United States); García, Luciano [Observatorio Astronómico de Córdoba Universidad Nacional de Córdoba Laprida 854, X5000BGR, Córdoba (Argentina); Jung, Dawoon [Korea Aerospace Research Institute Lunar Exploration Program Office 169-84 Gwahak-ro, Yuseong-gu, Daejeon 34133 (Korea, Republic of); Lintott, Chris [Denys Wilkinson Building Keble Road Oxford, OX1 3RH (United Kingdom); Rebull, Luisa M. [Infrared Processing and Analaysis Center Caltech M/S 314-6 1200 E. California Blvd. Pasadena, CA 91125 (United States); Nesvold, Erika, E-mail: Marc.Kuchner@nasa.gov, E-mail: michael.w.mcelwain@nasa.gov, E-mail: deborah.l.padgett@nasa.gov, E-mail: carol.a.grady@nasa.gov, E-mail: silverberg@ou.edu, E-mail: wisniewski@ou.edu [Department of Terrestrial Magnetism, Carnegie Institution of Washington, 5241 Broad Branch Road, NW, Washington, DC 20015-1305 (United States); Collaboration: Disk Detective Collaboration; and others

2016-10-20

The Disk Detective citizen science project aims to find new stars with 22 μ m excess emission from circumstellar dust using data from NASA’s Wide-field Infrared Survey Explorer ( WISE ) mission. Initial cuts on the AllWISE catalog provide an input catalog of 277,686 sources. Volunteers then view images of each source online in 10 different bands to identify false positives (galaxies, interstellar matter, image artifacts, etc.). Sources that survive this online vetting are followed up with spectroscopy on the FLWO Tillinghast telescope. This approach should allow us to unleash the full potential of WISE for finding new debris disks and protoplanetary disks. We announce a first list of 37 new disk candidates discovered by the project, and we describe our vetting and follow-up process. One of these systems appears to contain the first debris disk discovered around a star with a white dwarf companion: HD 74389. We also report four newly discovered classical Be stars (HD 6612, HD 7406, HD 164137, and HD 218546) and a new detection of 22 μ m excess around the previously known debris disk host star HD 22128.

DISK DETECTIVE: DISCOVERY OF NEW CIRCUMSTELLAR DISK CANDIDATES THROUGH CITIZEN SCIENCE

International Nuclear Information System (INIS)

Kuchner, Marc J.; McElwain, Michael; Padgett, Deborah L.; Silverberg, Steven M.; Wisniewski, John P.; Bans, Alissa S.; Bhattacharjee, Shambo; Kenyon, Scott J.; Debes, John H.; Currie, Thayne; García, Luciano; Jung, Dawoon; Lintott, Chris; Rebull, Luisa M.; Nesvold, Erika

2016-01-01

The Disk Detective citizen science project aims to find new stars with 22 μ m excess emission from circumstellar dust using data from NASA’s Wide-field Infrared Survey Explorer ( WISE ) mission. Initial cuts on the AllWISE catalog provide an input catalog of 277,686 sources. Volunteers then view images of each source online in 10 different bands to identify false positives (galaxies, interstellar matter, image artifacts, etc.). Sources that survive this online vetting are followed up with spectroscopy on the FLWO Tillinghast telescope. This approach should allow us to unleash the full potential of WISE for finding new debris disks and protoplanetary disks. We announce a first list of 37 new disk candidates discovered by the project, and we describe our vetting and follow-up process. One of these systems appears to contain the first debris disk discovered around a star with a white dwarf companion: HD 74389. We also report four newly discovered classical Be stars (HD 6612, HD 7406, HD 164137, and HD 218546) and a new detection of 22 μ m excess around the previously known debris disk host star HD 22128.

Disk Detective: Discovery of New Circumstellar Disk Candidates Through Citizen Science

Science.gov (United States)

Kuchner, Marc J.; Silverberg, Steven M.; Bans, Alissa S.; Bhattacharjee, Shambo; Kenyon, Scott J.; Debes, John H.; Currie, Thayne; Garcia, Luciano; Jung, Dawoon; Lintott, Chris;

Magnetohydrodynamics of accretion disks

International Nuclear Information System (INIS)

Torkelsson, U.

1994-04-01

The thesis consists of an introduction and summary, and five research papers. The introduction and summary provides the background in accretion disk physics and magnetohydrodynamics. The research papers describe numerical studies of magnetohydrodynamical processes in accretion disks. Paper 1 is a one-dimensional study of the effect of magnetic buoyancy on a flux tube in an accretion disk. The stabilizing influence of an accretion disk corona on the flux tube is demonstrated. Paper 2-4 present numerical simulations of mean-field dynamos in accretion disks. Paper 11 verifies the correctness of the numerical code by comparing linear models to previous work by other groups. The results are also extended to somewhat modified disk models. A transition from an oscillatory mode of negative parity for thick disks to a steady mode of even parity for thin disks is found. Preliminary results for nonlinear dynamos at very high dynamo numbers are also presented. Paper 3 describes the bifurcation behaviour of the nonlinear dynamos. For positive dynamo numbers it is found that the initial steady solution is replaced by an oscillatory solution of odd parity. For negative dynamo numbers the solution becomes chaotic at sufficiently high dynamo numbers. Paper 4 continues the studies of nonlinear dynamos, and it is demonstrated that a chaotic solution appears even for positive dynamo numbers, but that it returns to a steady solution of mixed parity at very high dynamo numbers. Paper 5 describes a first attempt at simulating the small-scale turbulence of an accretion disk in three dimensions. There is only find cases of decaying turbulence, but this is rather due to limitations of the simulations than that turbulence is really absent in accretion disks

Preparation of thin actinide metal disks using a multiple disk casting technique

International Nuclear Information System (INIS)

Conner, W.V.

1975-01-01

A casting technique has been developed for preparing multiple actinide metal disks which have a minimum thickness of 0.006 inch. This technique was based on an injection casting procedure which utilizes the weight of a tantalum metal rod to force the molten metal into the mold cavity. Using the proper mold design and casting parameters, it has been possible to prepare ten 1/2 inch diameter neptunium or plutonium metal disks in a single casting, This casting technique is capable of producing disks which are very uniform. The average thickness of the disks from a typical casting will vary no more than 0.001 inch and the variation in the thickness of the individual disks will range from 0.0001 to 0.0005 inch. (Auth.)

Preparation of thin actinide metal disks using a multiple disk casting technique

International Nuclear Information System (INIS)

Conner, W.V.

1976-01-01

A casting technique has been developed for preparing multiple actinide metal disks which have a minimum thickness of 0.006 inch. This technique was based on an injection casting procedure which utilizes the weight of a tantalum metal rod to force the molten metal into the mold cavity. Using the proper mold design and casting parameters, it has been possible to prepare ten 1/2 inch diameter neptunium or plutonium metal disks in a single casting. This casting technique is capable of producing disks which are very uniform. The average thickness of the disks from a typical casting will vary no more than 0.001 inch and the variation in the thickness of the individual disks will range from 0.0001 to 0.0005 inch. (author)

ON THE TRANSITIONAL DISK CLASS: LINKING OBSERVATIONS OF T TAURI STARS AND PHYSICAL DISK MODELS

International Nuclear Information System (INIS)

Espaillat, C.; Andrews, S.; Qi, C.; Wilner, D.; Ingleby, L.; Calvet, N.; Hernández, J.; Furlan, E.; D'Alessio, P.; Muzerolle, J.

2012-01-01

Two decades ago 'transitional disks' (TDs) described spectral energy distributions (SEDs) of T Tauri stars with small near-IR excesses, but significant mid- and far-IR excesses. Many inferred this indicated dust-free holes in disks possibly cleared by planets. Recently, this term has been applied disparately to objects whose Spitzer SEDs diverge from the expectations for a typical full disk (FD). Here, we use irradiated accretion disk models to fit the SEDs of 15 such disks in NGC 2068 and IC 348. One group has a 'dip' in infrared emission while the others' continuum emission decreases steadily at all wavelengths. We find that the former have an inner disk hole or gap at intermediate radii in the disk and we call these objects 'transitional disks' and 'pre-transitional disks' (PTDs), respectively. For the latter group, we can fit these SEDs with FD models and find that millimeter data are necessary to break the degeneracy between dust settling and disk mass. We suggest that the term 'transitional' only be applied to objects that display evidence for a radical change in the disk's radial structure. Using this definition, we find that TDs and PTDs tend to have lower mass accretion rates than FDs and that TDs have lower accretion rates than PTDs. These reduced accretion rates onto the star could be linked to forming planets. Future observations of TDs and PTDs will allow us to better quantify the signatures of planet formation in young disks.

THE SPITZER INFRARED SPECTROGRAPH SURVEY OF PROTOPLANETARY DISKS IN ORION A. I. DISK PROPERTIES

Energy Technology Data Exchange (ETDEWEB)

Kim, K. H. [Korea Astronomy and Space Science Institute (KASI), 776, Daedeokdae-ro, Yuseong-gu, Daejeon 305-348 (Korea, Republic of); Watson, Dan M.; Manoj, P.; Forrest, W. J. [Department of Physics and Astronomy, University of Rochester, Rochester, NY 14627 (United States); Furlan, Elise [Infrared Processing and Analysis Center, Caltech, 770 S. Wilson Avenue, Pasadena, CA 91125 (United States); Najita, Joan [National Optical Astronomy Observatory, 950 North Cherry Avenue, Tucson, AZ 85719 (United States); Sargent, Benjamin [Center for Imaging Science and Laboratory for Multiwavelength Astrophysics, Rochester Institute of Technology, 54 Lomb Memorial Dr., Rochester, NY 14623 (United States); Hernández, Jesús [Centro de Investigaciones de Astronomía, Apdo. Postal 264, Mérida 5101-A (Venezuela, Bolivarian Republic of); Calvet, Nuria [Department of Astronomy, University of Michigan, 830 Dennison Building, 500 Church Street, Ann Arbor, MI 48109 (United States); Adame, Lucía [Facultad de Ciencias Físico-Matemáticas, Universidad Autónoma de Nuevo León, Av. Universidad S/N, San Nicolás de los Garza, Nuevo León, C.P. 66451, México (Mexico); Espaillat, Catherine [Department of Astronomy, Boston University, 725 Commonwealth Avenue, Boston, MA 02215 (United States); Megeath, S. T. [Ritter Astrophysical Research Center, Department of Physics and Astronomy, University of Toledo, 2801 W. Bancroft St., Toledo, OH 43606 (United States); Muzerolle, James, E-mail: quarkosmos@kasi.re.kr [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); and others

2016-09-01

We present our investigation of 319 Class II objects in Orion A observed by Spitzer /IRS. We also present the follow-up observations of 120 of these Class II objects in Orion A from the Infrared Telescope Facility/SpeX. We measure continuum spectral indices, equivalent widths, and integrated fluxes that pertain to disk structure and dust composition from IRS spectra of Class II objects in Orion A. We estimate mass accretion rates using hydrogen recombination lines in the SpeX spectra of our targets. Utilizing these properties, we compare the distributions of the disk and dust properties of Orion A disks with those of Taurus disks with respect to position within Orion A (Orion Nebular Cluster [ONC] and L1641) and with the subgroups by the inferred radial structures, such as transitional disks (TDs) versus radially continuous full disks (FDs). Our main findings are as follows. (1) Inner disks evolve faster than the outer disks. (2) The mass accretion rates of TDs and those of radially continuous FDs are statistically significantly displaced from each other. The median mass accretion rate of radially continuous disks in the ONC and L1641 is not very different from that in Taurus. (3) Less grain processing has occurred in the disks in the ONC compared to those in Taurus, based on analysis of the shape index of the 10 μ m silicate feature ( F {sub 11.3}/ F {sub 9.8}). (4) The 20–31 μ m continuum spectral index tracks the projected distance from the most luminous Trapezium star, θ {sup 1} Ori C. A possible explanation is UV ablation of the outer parts of disks.

Brown dwarf disks with ALMA

Energy Technology Data Exchange (ETDEWEB)

Ricci, L.; Isella, A. [Department of Astronomy, California Institute of Technology, MC 249-17, Pasadena, CA 91125 (United States); Testi, L.; De Gregorio-Monsalvo, I. [European Southern Observatory, Karl-Schwarzschild-Strasse 2, D-85748 Garching (Germany); Natta, A. [INAF-Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, I-50125 Firenze (Italy); Scholz, A., E-mail: lricci@astro.caltech.edu [School of Cosmic Physics, Dublin Institute for Advanced Studies, 31 Fitzwilliam Place, Dublin 2 (Ireland)

2014-08-10

We present Atacama Large Millimeter/submillimeter Array continuum and spectral line data at 0.89 mm and 3.2 mm for three disks surrounding young brown dwarfs and very low mass stars in the Taurus star forming region. Dust thermal emission is detected and spatially resolved for all the three disks, while CO(J = 3-2) emission is seen in two disks. We analyze the continuum visibilities and constrain the disks' physical structure in dust. The results of our analysis show that the disks are relatively large; the smallest one has an outer radius of about 70 AU. The inferred disk radii, radial profiles of the dust surface density, and disk to central object mass ratios lie within the ranges found for disks around more massive young stars. We derive from our observations the wavelength dependence of the millimeter dust opacity. In all the three disks, data are consistent with the presence of grains with at least millimeter sizes, as also found for disks around young stars, and confirm that the early stages of the solid growth toward planetesimals occur also around very low-mass objects. We discuss the implications of our findings on models of solids evolution in protoplanetary disks, the main mechanisms proposed for the formation of brown dwarfs and very low-mass stars, as well as the potential of finding rocky and giant planets around very low-mass objects.

PLANETESIMAL DISK MICROLENSING

International Nuclear Information System (INIS)

Heng, Kevin; Keeton, Charles R.

2009-01-01

Motivated by debris disk studies, we investigate the gravitational microlensing of background starlight by a planetesimal disk around a foreground star. We use dynamical survival models to construct a plausible example of a planetesimal disk and study its microlensing properties using established ideas of microlensing by small bodies. When a solar-type source star passes behind a planetesimal disk, the microlensing light curve may exhibit short-term, low-amplitude residuals caused by planetesimals several orders of magnitude below Earth mass. The minimum planetesimal mass probed depends on the photometric sensitivity and the size of the source star, and is lower when the planetesimal lens is located closer to us. Planetesimal lenses may be found more nearby than stellar lenses because the steepness of the planetesimal mass distribution changes how the microlensing signal depends on the lens/source distance ratio. Microlensing searches for planetesimals require essentially continuous monitoring programs that are already feasible and can potentially set constraints on models of debris disks, the progeny of the supposed extrasolar analogues of Kuiper Belts.

Dusty disks around young stars

NARCIS (Netherlands)

Verhoeff, A.

2009-01-01

Stars are formed through the collapse of giant molecular clouds. During this contraction the matter spins up and naturally forms a circumstellar disk. Once accretion comes to a halt, these disks are relatively stable. Some disks are known to last up to 10 Myrs. Most disks however, dissipate on

Debris Disks: Probing Planet Formation

OpenAIRE

Wyatt, Mark C.

2018-01-01

Debris disks are the dust disks found around ~20% of nearby main sequence stars in far-IR surveys. They can be considered as descendants of protoplanetary disks or components of planetary systems, providing valuable information on circumstellar disk evolution and the outcome of planet formation. The debris disk population can be explained by the steady collisional erosion of planetesimal belts; population models constrain where (10-100au) and in what quantity (>1Mearth) planetesimals (>10km i...

Fast, Capacious Disk Memory Device

Science.gov (United States)

Muller, Ronald M.

1990-01-01

Device for recording digital data on, and playing back data from, memory disks has high recording or playback rate and utilizes available recording area more fully. Two disks, each with own reading/writing head, used to record data at same time. Head on disk A operates on one of tracks numbered from outside in; head on disk B operates on track of same number in sequence from inside out. Underlying concept of device applicable to magnetic or optical disks.

Mass distributions in disk galaxies

NARCIS (Netherlands)

Martinsson, Thomas; Verheijen, Marc; Bershady, Matthew; Westfall, Kyle; Andersen, David; Swaters, Rob

We present results on luminous and dark matter mass distributions in disk galaxies from the DiskMass Survey. As expected for normal disk galaxies, stars dominate the baryonic mass budget in the inner region of the disk; however, at about four optical scale lengths (hR ) the atomic gas starts to

WIND-ACCRETION DISKS IN WIDE BINARIES, SECOND-GENERATION PROTOPLANETARY DISKS, AND ACCRETION ONTO WHITE DWARFS

International Nuclear Information System (INIS)

Perets, Hagai B.; Kenyon, Scott J.

2013-01-01

Mass transfer from an evolved donor star to its binary companion is a standard feature of stellar evolution in binaries. In wide binaries, the companion star captures some of the mass ejected in a wind by the primary star. The captured material forms an accretion disk. Here, we study the evolution of wind-accretion disks, using a numerical approach which allows us to follow the long-term evolution. For a broad range of initial conditions, we derive the radial density and temperature profiles of the disk. In most cases, wind accretion leads to long-lived stable disks over the lifetime of the asymptotic giant branch donor star. The disks have masses of a few times 10 –5 -10 –3 M ☉ , with surface density and temperature profiles that follow broken power laws. The total mass in the disk scales approximately linearly with the viscosity parameter used. Roughly, 50%-80% of the mass falling into the disk accretes onto the central star; the rest flows out through the outer edge of the disk into the stellar wind of the primary. For systems with large accretion rates, the secondary accretes as much as 0.1 M ☉ . When the secondary is a white dwarf, accretion naturally leads to nova and supernova eruptions. For all types of secondary star, the surface density and temperature profiles of massive disks resemble structures observed in protoplanetary disks, suggesting that coordinated observational programs might improve our understanding of uncertain disk physics.

A High-mass Protobinary System with Spatially Resolved Circumstellar Accretion Disks and Circumbinary Disk

Energy Technology Data Exchange (ETDEWEB)

Kraus, S.; Kluska, J.; Kreplin, A.; Bate, M.; Harries, T. J.; Hone, E.; Anugu, A. [School of Physics, Astrophysics Group, University of Exeter, Stocker Road, Exeter EX4 4QL (United Kingdom); Hofmann, K.-H.; Weigelt, G. [Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn (Germany); Monnier, J. D. [Department of Astronomy, University of Michigan, 311 West Hall, 1085 South University Avenue, Ann Arbor, MI 48109 (United States); De Wit, W. J. [ESO, Alonso de Cordova 3107, Vitacura, Santiago 19 (Chile); Wittkowski, M., E-mail: skraus@astro.ex.ac.uk [ESO, Karl-Schwarzschild-Str. 2, D-85748 Garching bei München (Germany)

2017-01-20

High-mass multiples might form via fragmentation of self-gravitational disks or alternative scenarios such as disk-assisted capture. However, only a few observational constraints exist on the architecture and disk structure of high-mass protobinaries and their accretion properties. Here, we report the discovery of a close (57.9 ± 0.2 mas = 170 au) high-mass protobinary, IRAS17216-3801, where our VLTI/GRAVITY+AMBER near-infrared interferometry allows us to image the circumstellar disks around the individual components with ∼3 mas resolution. We estimate the component masses to ∼20 and ∼18 M {sub ⊙} and find that the radial intensity profiles can be reproduced with an irradiated disk model, where the inner regions are excavated of dust, likely tracing the dust sublimation region in these disks. The circumstellar disks are strongly misaligned with respect to the binary separation vector, which indicates that the tidal forces did not have time to realign the disks, pointing toward a young dynamical age of the system. We constrain the distribution of the Br γ and CO-emitting gas using VLTI/GRAVITY spectro-interferometry and VLT/CRIRES spectro-astrometry and find that the secondary is accreting at a higher rate than the primary. VLT/NACO imaging shows L ′-band emission on (3–4)× larger scales than the binary separation, matching the expected dynamical truncation radius for the circumbinary disk. The IRAS17216-3801 system is ∼3× more massive and ∼5× more compact than other high-mass multiplies imaged at infrared wavelength and the first high-mass protobinary system where circumstellar and circumbinary dust disks could be spatially resolved. This opens exciting new opportunities for studying star–disk interactions and the role of multiplicity in high-mass star formation.

Source to Accretion Disk Tilt

OpenAIRE

Montgomery, M. M.; Martin, E. L.

2010-01-01

Many different system types retrogradely precess, and retrograde precession could be from a tidal torque by the secondary on a misaligned accretion disk. However, a source to cause and maintain disk tilt is unknown. In this work, we show that accretion disks can tilt due to a force called lift. Lift results from differing gas stream supersonic speeds over and under an accretion disk. Because lift acts at the disk's center of pressure, a torque is applied around a rotation axis passing through...

Evolution of magnetic disk subsystems

Science.gov (United States)

Kaneko, Satoru

1994-06-01

The higher recording density of magnetic disk realized today has brought larger storage capacity per unit and smaller form factors. If the required access performance per MB is constant, the performance of large subsystems has to be several times better. This article describes mainly the technology for improving the performance of the magnetic disk subsystems and the prospects of their future evolution. Also considered are 'crosscall pathing' which makes the data transfer channel more effective, 'disk cache' which improves performance coupling with solid state memory technology, and 'RAID' which improves the availability and integrity of disk subsystems by organizing multiple disk drives in a subsystem. As a result, it is concluded that since the performance of the subsystem is dominated by that of the disk cache, maximation of the performance of the disk cache subsystems is very important.

STELLAR MASS DEPENDENT DISK DISPERSAL

International Nuclear Information System (INIS)

Kennedy, Grant M.; Kenyon, Scott J.

2009-01-01

We use published optical spectral and infrared (IR) excess data from nine young clusters and associations to study the stellar mass dependent dispersal of circumstellar disks. All clusters older than ∼3 Myr show a decrease in disk fraction with increasing stellar mass for solar to higher mass stars. This result is significant at about the 1σ level in each cluster. For the complete set of clusters we reject the null hypothesis-that solar and intermediate-mass stars lose their disks at the same rate-with 95%-99.9% confidence. To interpret this behavior, we investigate the impact of grain growth, binary companions, and photoevaporation on the evolution of disk signatures. Changes in grain growth timescales at fixed disk temperature may explain why early-type stars with IR excesses appear to evolve faster than their later-type counterparts. Little evidence that binary companions affect disk evolution suggests that photoevaporation is the more likely mechanism for disk dispersal. A simple photoevaporation model provides a good fit to the observed disk fractions for solar and intermediate-mass stars. Although the current mass-dependent disk dispersal signal is not strong, larger and more complete samples of clusters with ages of 3-5 Myr can improve the significance and provide better tests of theoretical models. In addition, the orbits of extra-solar planets can constrain models of disk dispersal and migration. We suggest that the signature of stellar mass dependent disk dispersal due to photoevaporation may be present in the orbits of observed extra-solar planets. Planets orbiting hosts more massive than ∼1.6 M sun may have larger orbits because the disks in which they formed were dispersed before they could migrate.

Manipulation of magnetic vortex parameters in disk-on-disk nanostructures with various geometry

Directory of Open Access Journals (Sweden)

Maxim E. Stebliy

2015-03-01

Full Text Available Magnetic nanostructures in the form of a sandwich consisting of two permalloy (Py disks with diameters of 600 and 200 nm separated by a nonmagnetic interlayer are studied. Magnetization reversal of the disk-on-disk nanostructures depends on the distance between centers of the small and big disks and on orientation of an external magnetic field applied during measurements. It is found that manipulation of the magnetic vortex chirality and the trajectory of the vortex core in the big disk is only possible in asymmetric nanostructures. Experimentally studied peculiarities of a motion path of the vortex core and vortex parameters by the magneto-optical Kerr effect (MOKE magnetometer are supported by the magnetic force microscopy imaging and micromagnetic simulations.

Global Simulations of the Inner Regions of Protoplanetary Disks with Comprehensive Disk Microphysics

Energy Technology Data Exchange (ETDEWEB)

Bai, Xue-Ning, E-mail: xbai@cfa.harvard.edu [Institute for Theory and Computation, Harvard-Smithsonian Center for Astrophysics, 60 Garden St., MS-51, Cambridge, MA 02138 (United States)

2017-08-10

The gas dynamics of weakly ionized protoplanetary disks (PPDs) are largely governed by the coupling between gas and magnetic fields, described by three non-ideal magnetohydrodynamical (MHD) effects (Ohmic, Hall, ambipolar). Previous local simulations incorporating these processes have revealed that the inner regions of PPDs are largely laminar and accompanied by wind-driven accretion. We conduct 2D axisymmetric, fully global MHD simulations of these regions (∼1–20 au), taking into account all non-ideal MHD effects, with tabulated diffusion coefficients and approximate treatment of external ionization and heating. With the net vertical field aligned with disk rotation, the Hall-shear instability strongly amplifies horizontal magnetic field, making the overall dynamics dependent on initial field configuration. Following disk formation, the disk likely relaxes into an inner zone characterized by asymmetric field configuration across the midplane, which smoothly transitions to a more symmetric outer zone. Angular momentum transport is driven by both MHD winds and laminar Maxwell stress, with both accretion and decretion flows present at different heights, and modestly asymmetric winds from the two disk sides. With anti-aligned field polarity, weakly magnetized disks settle into an asymmetric field configuration with supersonic accretion flow concentrated at one side of the disk surface, and highly asymmetric winds between the two disk sides. In all cases, the wind is magneto-thermal in nature, characterized by a mass loss rate exceeding the accretion rate. More strongly magnetized disks give more symmetric field configuration and flow structures. Deeper far-UV penetration leads to stronger and less stable outflows. Implications for observations and planet formation are also discussed.

Global Simulations of the Inner Regions of Protoplanetary Disks with Comprehensive Disk Microphysics

Science.gov (United States)

Bai, Xue-Ning

2017-08-01

The gas dynamics of weakly ionized protoplanetary disks (PPDs) are largely governed by the coupling between gas and magnetic fields, described by three non-ideal magnetohydrodynamical (MHD) effects (Ohmic, Hall, ambipolar). Previous local simulations incorporating these processes have revealed that the inner regions of PPDs are largely laminar and accompanied by wind-driven accretion. We conduct 2D axisymmetric, fully global MHD simulations of these regions (˜1-20 au), taking into account all non-ideal MHD effects, with tabulated diffusion coefficients and approximate treatment of external ionization and heating. With the net vertical field aligned with disk rotation, the Hall-shear instability strongly amplifies horizontal magnetic field, making the overall dynamics dependent on initial field configuration. Following disk formation, the disk likely relaxes into an inner zone characterized by asymmetric field configuration across the midplane, which smoothly transitions to a more symmetric outer zone. Angular momentum transport is driven by both MHD winds and laminar Maxwell stress, with both accretion and decretion flows present at different heights, and modestly asymmetric winds from the two disk sides. With anti-aligned field polarity, weakly magnetized disks settle into an asymmetric field configuration with supersonic accretion flow concentrated at one side of the disk surface, and highly asymmetric winds between the two disk sides. In all cases, the wind is magneto-thermal in nature, characterized by a mass loss rate exceeding the accretion rate. More strongly magnetized disks give more symmetric field configuration and flow structures. Deeper far-UV penetration leads to stronger and less stable outflows. Implications for observations and planet formation are also discussed.

WIND-ACCRETION DISKS IN WIDE BINARIES, SECOND-GENERATION PROTOPLANETARY DISKS, AND ACCRETION ONTO WHITE DWARFS

Energy Technology Data Exchange (ETDEWEB)

Perets, Hagai B. [Technion-Israel Institute of Technology, Haifa (Israel); Kenyon, Scott J., E-mail: hperets@physics.technion.ac.il [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

2013-02-20

Mass transfer from an evolved donor star to its binary companion is a standard feature of stellar evolution in binaries. In wide binaries, the companion star captures some of the mass ejected in a wind by the primary star. The captured material forms an accretion disk. Here, we study the evolution of wind-accretion disks, using a numerical approach which allows us to follow the long-term evolution. For a broad range of initial conditions, we derive the radial density and temperature profiles of the disk. In most cases, wind accretion leads to long-lived stable disks over the lifetime of the asymptotic giant branch donor star. The disks have masses of a few times 10{sup -5}-10{sup -3} M {sub Sun }, with surface density and temperature profiles that follow broken power laws. The total mass in the disk scales approximately linearly with the viscosity parameter used. Roughly, 50%-80% of the mass falling into the disk accretes onto the central star; the rest flows out through the outer edge of the disk into the stellar wind of the primary. For systems with large accretion rates, the secondary accretes as much as 0.1 M {sub Sun }. When the secondary is a white dwarf, accretion naturally leads to nova and supernova eruptions. For all types of secondary star, the surface density and temperature profiles of massive disks resemble structures observed in protoplanetary disks, suggesting that coordinated observational programs might improve our understanding of uncertain disk physics.

Vibration of imperfect rotating disk

Directory of Open Access Journals (Sweden)

Půst L.

2011-12-01

Full Text Available This study is concerned with the theoretical and numerical calculations of the flexural vibrations of a bladed disk. The main focus of this study is to elaborate the basic background for diagnostic and identification methods for ascertaining the main properties of the real structure or an experimental model of turbine disks. The reduction of undesirable vibrations of blades is proposed by using damping heads, which on the experimental model of turbine disk are applied only on a limited number of blades. This partial setting of damping heads introduces imperfection in mass, stiffness and damping distribution on the periphery and leads to more complicated dynamic properties than those of a perfect disk. Calculation of FEM model and analytic—numerical solution of disk behaviour in the limited (two modes frequency range shows the splitting of resonance with an increasing speed of disk rotation. The spectrum of resonance is twice denser than that of a perfect disk.

RINGED ACCRETION DISKS: EQUILIBRIUM CONFIGURATIONS

Energy Technology Data Exchange (ETDEWEB)

Pugliese, D.; Stuchlík, Z., E-mail: d.pugliese.physics@gmail.com, E-mail: zdenek.stuchlik@physics.cz [Institute of Physics and Research Centre of Theoretical Physics and Astrophysics, Faculty of Philosophy and Science, Silesian University in Opava, Bezručovo náměstí 13, CZ-74601 Opava (Czech Republic)

2015-12-15

We investigate a model of a ringed accretion disk, made up by several rings rotating around a supermassive Kerr black hole attractor. Each toroid of the ringed disk is governed by the general relativity hydrodynamic Boyer condition of equilibrium configurations of rotating perfect fluids. Properties of the tori can then be determined by an appropriately defined effective potential reflecting the background Kerr geometry and the centrifugal effects. The ringed disks could be created in various regimes during the evolution of matter configurations around supermassive black holes. Therefore, both corotating and counterrotating rings have to be considered as being a constituent of the ringed disk. We provide constraints on the model parameters for the existence and stability of various ringed configurations and discuss occurrence of accretion onto the Kerr black hole and possible launching of jets from the ringed disk. We demonstrate that various ringed disks can be characterized by a maximum number of rings. We present also a perturbation analysis based on evolution of the oscillating components of the ringed disk. The dynamics of the unstable phases of the ringed disk evolution seems to be promising in relation to high-energy phenomena demonstrated in active galactic nuclei.

CN rings in full protoplanetary disks around young stars as probes of disk structure

Science.gov (United States)

Cazzoletti, P.; van Dishoeck, E. F.; Visser, R.; Facchini, S.; Bruderer, S.

2018-01-01

Aims: Bright ring-like structure emission of the CN molecule has been observed in protoplanetary disks. We investigate whether such structures are due to the morphology of the disk itself or if they are instead an intrinsic feature of CN emission. With the intention of using CN as a diagnostic, we also address to which physical and chemical parameters CN is most sensitive. Methods: A set of disk models were run for different stellar spectra, masses, and physical structures via the 2D thermochemical code DALI. An updated chemical network that accounts for the most relevant CN reactions was adopted. Results: Ring-shaped emission is found to be a common feature of all adopted models; the highest abundance is found in the upper outer regions of the disk, and the column density peaks at 30-100 AU for T Tauri stars with standard accretion rates. Higher mass disks generally show brighter CN. Higher UV fields, such as those appropriate for T Tauri stars with high accretion rates or for Herbig Ae stars or for higher disk flaring, generally result in brighter and larger rings. These trends are due to the main formation paths of CN, which all start with vibrationally excited H_2^* molecules, that are produced through far ultraviolet (FUV) pumping of H2. The model results compare well with observed disk-integrated CN fluxes and the observed location of the CN ring for the TW Hya disk. Conclusions: CN rings are produced naturally in protoplanetary disks and do not require a specific underlying disk structure such as a dust cavity or gap. The strong link between FUV flux and CN emission can provide critical information regarding the vertical structure of the disk and the distribution of dust grains which affects the UV penetration, and could help to break some degeneracies in the SED fitting. In contrast with C2H or c-C3H2, the CN flux is not very sensitive to carbon and oxygen depletion.

HERSCHEL OBSERVATIONS OF THE T CHA TRANSITION DISK: CONSTRAINING THE OUTER DISK PROPERTIES

International Nuclear Information System (INIS)

Cieza, Lucas A.; Olofsson, Johan; Henning, Thomas; Harvey, Paul M.; Evans II, Neal J.; Pinte, Christophe; Augereau, Jean-Charles; Ménard, Francois; Merín, Bruno; Najita, Joan

2011-01-01

T Cha is a nearby (d ∼ 100 pc) transition disk known to have an optically thin gap separating optically thick inner and outer disk components. Huélamo et al. recently reported the presence of a low-mass object candidate within the gap of the T Cha disk, giving credence to the suspected planetary origin of this gap. Here we present the Herschel photometry (70, 160, 250, 350, and 500 μm) of T Cha from the 'Dust, Ice, and Gas in Time' Key Program, which bridges the wavelength range between existing Spitzer and millimeter data and provide important constraints on the outer disk properties of this extraordinary system. We model the entire optical to millimeter wavelength spectral energy distribution (SED) of T Cha (19 data points between 0.36 and 3300 μm without any major gaps in wavelength coverage). T Cha shows a steep spectral slope in the far-IR, which we find clearly favors models with outer disks containing little or no dust beyond ∼40 AU. The full SED can be modeled equally well with either an outer disk that is very compact (only a few AU wide) or a much larger one that has a very steep surface density profile. That is, T Cha's outer disk seems to be either very small or very tenuous. Both scenarios suggest a highly unusual outer disk and have important but different implications for the nature of T Cha. Spatially resolved images are needed to distinguish between the two scenarios.

HERSCHEL OBSERVATIONS OF THE T CHA TRANSITION DISK: CONSTRAINING THE OUTER DISK PROPERTIES

Energy Technology Data Exchange (ETDEWEB)

Cieza, Lucas A. [Institute for Astronomy, University of Hawaii at Manoa, Honolulu, HI 96822 (United States); Olofsson, Johan; Henning, Thomas [Max Planck Institut fuer Astronomie, Koenigstuhl 17, 69117 Heidelberg (Germany); Harvey, Paul M.; Evans II, Neal J. [Department of Astronomy, University of Texas at Austin, Austin, TX 78712 (United States); Pinte, Christophe; Augereau, Jean-Charles; Menard, Francois [UJF-Grenoble 1/CNRS-INSU, Institut de Planetologie et d' Astrophysique de Grenoble (IPAG) UMR 5274, Grenoble, F-38041 (France); Merin, Bruno [Herschel Science Centre, European Space Agency (ESAC), P.O. Box 78, 28691 Villanueva de la Canada, Madrid (Spain); Najita, Joan, E-mail: lcieza@ifa.hawaii.edu [National Optical Astronomy Observatory, 950 N. Cherry Avenue, Tucson, AZ 86719 (United States)

2011-11-10

T Cha is a nearby (d {approx} 100 pc) transition disk known to have an optically thin gap separating optically thick inner and outer disk components. Huelamo et al. recently reported the presence of a low-mass object candidate within the gap of the T Cha disk, giving credence to the suspected planetary origin of this gap. Here we present the Herschel photometry (70, 160, 250, 350, and 500 {mu}m) of T Cha from the 'Dust, Ice, and Gas in Time' Key Program, which bridges the wavelength range between existing Spitzer and millimeter data and provide important constraints on the outer disk properties of this extraordinary system. We model the entire optical to millimeter wavelength spectral energy distribution (SED) of T Cha (19 data points between 0.36 and 3300 {mu}m without any major gaps in wavelength coverage). T Cha shows a steep spectral slope in the far-IR, which we find clearly favors models with outer disks containing little or no dust beyond {approx}40 AU. The full SED can be modeled equally well with either an outer disk that is very compact (only a few AU wide) or a much larger one that has a very steep surface density profile. That is, T Cha's outer disk seems to be either very small or very tenuous. Both scenarios suggest a highly unusual outer disk and have important but different implications for the nature of T Cha. Spatially resolved images are needed to distinguish between the two scenarios.

Audit: Automated Disk Investigation Toolkit

Directory of Open Access Journals (Sweden)

Umit Karabiyik

2014-09-01

Full Text Available Software tools designed for disk analysis play a critical role today in forensics investigations. However, these digital forensics tools are often difficult to use, usually task specific, and generally require professionally trained users with IT backgrounds. The relevant tools are also often open source requiring additional technical knowledge and proper configuration. This makes it difficult for investigators without some computer science background to easily conduct the needed disk analysis. In this paper, we present AUDIT, a novel automated disk investigation toolkit that supports investigations conducted by non-expert (in IT and disk technology and expert investigators. Our proof of concept design and implementation of AUDIT intelligently integrates open source tools and guides non-IT professionals while requiring minimal technical knowledge about the disk structures and file systems of the target disk image.

YottaYotta announces new world record set for TCP disk-to-disk bulk transfer

CERN Document Server

2002-01-01

The Yottabyte NetStorage(TM) Company, today announced a new world record for TCP disk-to-disk data transfer using the company's NetStorager(R) System. The record-breaking demonstration transferred 5 terabytes of data between Chicago, Il. to Vancouver, BC and Ottawa, ON, at a sustained average throughput of 11.1 gigabits per second. Peak throughput exceeded 11.6 gigabits per second, more than 15-times faster than previous records for TCP transfer from disk-to-disk (1 page).

Disk-to-Disk network transfers at 100 Gb/s

Science.gov (United States)

Barczyk, Artur; Gable, Ian; Hay, Marilyn; Leavett-Brown, Colin; Legrand, Iosif; Lewall, Kim; McKee, Shawn; McWilliam, Donald; Mughal, Azher; Newman, Harvey; Rozsa, Sandor; Savard, Yvan; Sobie, Randall J.; Tam, Thomas; Voicu, Ramiro

2012-12-01

A 100 Gbps network was established between the California Institute of Technology conference booth at the Super Computing 2011 conference in Seattle, Washington and the computing center at the University of Victoria in Canada. A circuit was established over the BCNET, CANARIE and Super Computing (SCInet) networks using dedicated equipment. The small set of servers at the endpoints used a combination of 10GE and 40GE technologies, and SSD drives for data storage. The configuration of the network and the server configuration are discussed. We will show that the system was able to achieve disk-to-disk transfer rates of 60 Gbps and memory-to-memory rates in excess of 180 Gbps across the WAN. We will discuss the transfer tools, disk configurations, and monitoring tools used in the demonstration.

Disk-to-Disk network transfers at 100 Gb/s

International Nuclear Information System (INIS)

Barczyk, Artur; Legrand, Iosif; Mughal, Azher; Newman, Harvey; Rozsa, Sandor; Voicu, Ramiro; Gable, Ian; Leavett-Brown, Colin; Lewall, Kim; Savard, Yvan; Sobie, Randall J; Hay, Marilyn; McWilliam, Donald; McKee, Shawn; Tam, Thomas

2012-01-01

A 100 Gbps network was established between the California Institute of Technology conference booth at the Super Computing 2011 conference in Seattle, Washington and the computing center at the University of Victoria in Canada. A circuit was established over the BCNET, CANARIE and Super Computing (SCInet) networks using dedicated equipment. The small set of servers at the endpoints used a combination of 10GE and 40GE technologies, and SSD drives for data storage. The configuration of the network and the server configuration are discussed. We will show that the system was able to achieve disk-to-disk transfer rates of 60 Gbps and memory-to-memory rates in excess of 180 Gbps across the WAN. We will discuss the transfer tools, disk configurations, and monitoring tools used in the demonstration.

New classes of tough composite materials-Lessons from natural rigid biological systems

Energy Technology Data Exchange (ETDEWEB)

Mayer, G. [Department of Materials Science and Engineering, Box 352120, University of Washington, Seattle, WA 98195-2120 (United States)]. E-mail: gmayer@u.washington.edu

2006-09-15

The structures and properties of a new class of composite materials, containing a predominantly high volume fraction ceramic or glass phase, combined with minor organic (adhesive) phases, have been studied. These composites have unusual combinations of mechanical properties, such as stiffness, strength, and toughness. They are based on the architecture of a rigid natural material, the nacre structure, such as those found in the shells of the abalone Haliotis rufescens, and those of other mollusk shells. The mechanisms underlying these properties have also been studied. Analogs (utilizing high-performance engineering materials), that mimic many of the mechanisms underlying those superior combinations of properties, have been built. The results of the foregoing investigations are discussed. It was found that the toughness of segmented composite beams which have high volume fractions of ceramic (89 v / o) exceeded those of continuous layered beams, as well as the monolithic ceramic (alumina) on which they are based.

New classes of tough composite materials-Lessons from natural rigid biological systems

International Nuclear Information System (INIS)

Mayer, G.

2006-01-01

The structures and properties of a new class of composite materials, containing a predominantly high volume fraction ceramic or glass phase, combined with minor organic (adhesive) phases, have been studied. These composites have unusual combinations of mechanical properties, such as stiffness, strength, and toughness. They are based on the architecture of a rigid natural material, the nacre structure, such as those found in the shells of the abalone Haliotis rufescens, and those of other mollusk shells. The mechanisms underlying these properties have also been studied. Analogs (utilizing high-performance engineering materials), that mimic many of the mechanisms underlying those superior combinations of properties, have been built. The results of the foregoing investigations are discussed. It was found that the toughness of segmented composite beams which have high volume fractions of ceramic (89 v / o) exceeded those of continuous layered beams, as well as the monolithic ceramic (alumina) on which they are based

MODELING DUST EMISSION OF HL TAU DISK BASED ON PLANET–DISK INTERACTIONS

International Nuclear Information System (INIS)

Jin, Sheng; Ji, Jianghui; Li, Shengtai; Li, Hui; Isella, Andrea

2016-01-01

We use extensive global two-dimensional hydrodynamic disk gas+dust simulations with embedded planets, coupled with three-dimensional radiative transfer calculations, to model the dust ring and gap structures in the HL Tau protoplanetary disk observed with the Atacama Large Millimeter/Submillimeter Array (ALMA). We include the self-gravity of disk gas and dust components and make reasonable choices of disk parameters, assuming an already settled dust distribution and no planet migration. We can obtain quite adequate fits to the observed dust emission using three planets with masses of 0.35, 0.17, and 0.26 M Jup at 13.1, 33.0, and 68.6 AU, respectively. Implications for the planet formation as well as the limitations of this scenario are discussed

Fast disk array for image storage

Science.gov (United States)

Feng, Dan; Zhu, Zhichun; Jin, Hai; Zhang, Jiangling

1997-01-01

A fast disk array is designed for the large continuous image storage. It includes a high speed data architecture and the technology of data striping and organization on the disk array. The high speed data path which is constructed by two dual port RAM and some control circuit is configured to transfer data between a host system and a plurality of disk drives. The bandwidth can be more than 100 MB/s if the data path based on PCI (peripheral component interconnect). The organization of data stored on the disk array is similar to RAID 4. Data are striped on a plurality of disk, and each striping unit is equal to a track. I/O instructions are performed in parallel on the disk drives. An independent disk is used to store the parity information in the fast disk array architecture. By placing the parity generation circuit directly on the SCSI (or SCSI 2) bus, the parity information can be generated on the fly. It will affect little on the data writing in parallel on the other disks. The fast disk array architecture designed in the paper can meet the demands of the image storage.

Debris Disks in Aggregate: Using Hubble Space Telescope Coronagraphic Imagery to Understand the Scattered-Light Disk Detection Rate

Science.gov (United States)

Grady, Carol A.

2011-01-01

Despite more than a decade of coronagraphic imaging of debris disk candidate stars, only 16 have been imaged in scattered light. Since imaged disks provide our best insight into processes which sculpt disks, and can provide signposts of the presence of giant planets at distances which would elude radial velocity and transit surveys, we need to understand under what conditions we detect the disks in scattered light, how these disks differ from the majority of debris disks, and how to increase the yield of disks which are imaged with 0.1" angular resolution. In this talk, I will review what we have learned from a shallow HSTINICMOS NIR survey of debris disks, and present first results from our on-going HST /STIS optical imaging of bright scattered-light disks.

Coevolution of Binaries and Circumbinary Gaseous Disks

Science.gov (United States)

Fleming, David; Quinn, Thomas R.

2018-04-01

The recent discoveries of circumbinary planets by Kepler raise questions for contemporary planet formation models. Understanding how these planets form requires characterizing their formation environment, the circumbinary protoplanetary disk, and how the disk and binary interact. The central binary excites resonances in the surrounding protoplanetary disk that drive evolution in both the binary orbital elements and in the disk. To probe how these interactions impact both binary eccentricity and disk structure evolution, we ran N-body smooth particle hydrodynamics (SPH) simulations of gaseous protoplanetary disks surrounding binaries based on Kepler 38 for 10^4 binary orbital periods for several initial binary eccentricities. We find that nearly circular binaries weakly couple to the disk via a parametric instability and excite disk eccentricity growth. Eccentric binaries strongly couple to the disk causing eccentricity growth for both the disk and binary. Disks around sufficiently eccentric binaries strongly couple to the disk and develop an m = 1 spiral wave launched from the 1:3 eccentric outer Lindblad resonance (EOLR). This wave corresponds to an alignment of gas particle longitude of periastrons. We find that in all simulations, the binary semi-major axis decays due to dissipation from the viscous disk.

MOLECULAR GAS IN YOUNG DEBRIS DISKS

International Nuclear Information System (INIS)

Moor, A.; Abraham, P.; Kiss, Cs.; Juhasz, A.; Kospal, A.; Pascucci, I.; Apai, D.; Henning, Th.; Csengeri, T.; Grady, C.

2011-01-01

Gas-rich primordial disks and tenuous gas-poor debris disks are usually considered as two distinct evolutionary phases of the circumstellar matter. Interestingly, the debris disk around the young main-sequence star 49 Ceti possesses a substantial amount of molecular gas and possibly represents the missing link between the two phases. Motivated to understand the evolution of the gas component in circumstellar disks via finding more 49 Ceti-like systems, we carried out a CO J = 3-2 survey with the Atacama Pathfinder EXperiment, targeting 20 infrared-luminous debris disks. These systems fill the gap between primordial and old tenuous debris disks in terms of fractional luminosity. Here we report on the discovery of a second 49 Ceti-like disk around the 30 Myr old A3-type star HD21997, a member of the Columba Association. This system was also detected in the CO(2-1) transition, and the reliable age determination makes it an even clearer example of an old gas-bearing disk than 49 Ceti. While the fractional luminosities of HD21997 and 49 Ceti are not particularly high, these objects seem to harbor the most extended disks within our sample. The double-peaked profiles of HD21997 were reproduced by a Keplerian disk model combined with the LIME radiative transfer code. Based on their similarities, 49 Ceti and HD21997 may be the first representatives of a so far undefined new class of relatively old (∼>8 Myr), gaseous dust disks. From our results, neither primordial origin nor steady secondary production from icy planetesimals can unequivocally explain the presence of CO gas in the disk of HD21997.

Deformation and Life Analysis of Composite Flywheel Disk and Multi-disk Systems

Science.gov (United States)

Arnold, S. M.; Saleeb, A. F.; AlZoubi, N. R.

2001-01-01

In this study an attempt is made to put into perspective the problem of a rotating disk, be it a single disk or a number of concentric disks forming a unit. An analytical model capable of performing an elastic stress analysis for single/multiple, annular/solid, anisotropic/isotropic disk systems, subjected to both pressure surface tractions, body forces (in the form of temperature-changes and rotation fields) and interfacial misfits is derived and discussed. Results of an extensive parametric study are presented to clearly define the key design variables and their associated influence. In general the important parameters were identified as misfit, mean radius, thickness, material property and/or load gradation, and speed; all of which must be simultaneously optimized to achieve the "best" and most reliable design. Also, the important issue of defining proper performance/merit indices (based on the specific stored energy), in the presence of multiaxiality and material anisotropy is addressed. These merit indices are then utilized to discuss the difference between flywheels made from PMC and TMC materials with either an annular or solid geometry. Finally two major aspects of failure analysis, that is the static and cyclic limit (burst) speeds are addressed. In the case of static limit loads, upper, lower, and out-of-plane bounds for disks with constant thickness are presented for both the case of internal pressure loading (as one would see in a hydroburst test) and pure rotation (as in the case of a free spinning disk). The results (interaction diagrams) are displayed graphically in designer friendly format. For the case of fatigue, a representative fatigue/life master curve is illustrated in which the normalized limit speed versus number of applied cycles is given for a cladded TMC disk application.

FOMALHAUT'S DEBRIS DISK AND PLANET: CONSTRAINING THE MASS OF FOMALHAUT B FROM DISK MORPHOLOGY

International Nuclear Information System (INIS)

Chiang, E.; Kalas, P.; Graham, J. R.; Kite, E.; Clampin, M.

2009-01-01

Following the optical imaging of exoplanet candidate Fomalhaut b (Fom b), we present a numerical model of how Fomalhaut's debris disk is gravitationally shaped by a single interior planet. The model is simple, adaptable to other debris disks, and can be extended to accommodate multiple planets. If Fom b is the dominant perturber of the belt, then to produce the observed disk morphology it must have a mass M pl J , an orbital semimajor axis a pl > 101.5 AU, and an orbital eccentricity e pl = 0.11-0.13. These conclusions are independent of Fom b's photometry. To not disrupt the disk, a greater mass for Fom b demands a smaller orbit farther removed from the disk; thus, future astrometric measurement of Fom b's orbit, combined with our model of planet-disk interaction, can be used to determine the mass more precisely. The inner edge of the debris disk at a ∼ 133 AU lies at the periphery of Fom b's chaotic zone, and the mean disk eccentricity of e ∼ 0.11 is secularly forced by the planet, supporting predictions made prior to the discovery of Fom b. However, previous mass constraints based on disk morphology rely on several oversimplifications. We explain why our constraint is more reliable. It is based on a global model of the disk that is not restricted to the planet's chaotic zone boundary. Moreover, we screen disk parent bodies for dynamical stability over the system age of ∼ 100 Myr, and model them separately from their dust grain progeny; the latter's orbits are strongly affected by radiation pressure and their lifetimes are limited to ∼ 0.1 Myr by destructive grain-grain collisions. The single planet model predicts that planet and disk orbits be apsidally aligned. Fomalhaut b's nominal space velocity does not bear this out, but the astrometric uncertainties may be large. If the apsidal misalignment proves real, our calculated upper mass limit of 3M J still holds. If the orbits are aligned, our model predicts M pl = 0.5M J , a pl = 115 AU, and e pl = 0

DISCOVERY OF AN EDGE-ON DEBRIS DISK WITH A DUST RING AND AN OUTER DISK WING-TILT ASYMMETRY

International Nuclear Information System (INIS)

Kasper, Markus; Apai, Dániel; Wagner, Kevin; Robberto, Massimo

2015-01-01

Using Very Large Telescope/SPHERE near-infrared dual-band imaging and integral field spectroscopy, we discovered an edge-on debris disk around the 17 Myr old A-type member of the Scorpius–Centaurus OB association HD 110058. The edge-on disk can be traced to about 0.″6 or 65 AU projected separation. In its northern and southern wings, the disk shows at all wavelengths two prominent, bright, and symmetrically placed knots at 0.″3 or 32 AU from the star. We interpret these knots as a ring of planetesimals whose collisions may produce most of the dust observed in the disk. We find no evidence for a bow in the disk, but we identify a pair of symmetric, hooklike features in both wings. Based on similar features in the Beta Pictoris disk, we propose that this wing-tilt asymmetry traces either an outer planetesimal belt that is inclined with respect to the disk midplane or radiation-pressure-driven dust blown out from a yet unseen inner belt that is inclined with respect to the disk midplane. The misaligned inner or outer disk may be a result of interaction with a yet unseen planet. Overall, the disk geometry resembles the nearby disk around Beta Pictoris, albeit seen at smaller radial scales

CIRCUMSTELLAR DEBRIS DISKS: DIAGNOSING THE UNSEEN PERTURBER

Energy Technology Data Exchange (ETDEWEB)

Nesvold, Erika R. [Department of Terrestrial Magnetism, Carnegie Institution for Science, 5241 Broad Branch Rd., Washington, DC 20015 (United States); Naoz, Smadar; Vican, Laura [Department of Physics and Astronomy, UCLA, 475 Portola Plaza, Los Angeles, CA 90095 (United States); Farr, Will M. [School of Physics and Astronomy, University of Birmingham, Birmingham, B15 2TT (United Kingdom)

2016-07-20

The first indication of the presence of a circumstellar debris disk is usually the detection of excess infrared emission from the population of small dust grains orbiting the star. This dust is short-lived, requiring continual replenishment, and indicating that the disk must be excited by an unseen perturber. Previous theoretical studies have demonstrated that an eccentric planet orbiting interior to the disk will stir the larger bodies in the belt and produce dust via interparticle collisions. However, motivated by recent observations, we explore another possible mechanism for heating a debris disk: a stellar-mass perturber orbiting exterior to and inclined to the disk and exciting the disk particles’ eccentricities and inclinations via the Kozai–Lidov mechanism. We explore the consequences of an exterior perturber on the evolution of a debris disk using secular analysis and collisional N -body simulations. We demonstrate that a Kozai–Lidov excited disk can generate a dust disk via collisions and we compare the results of the Kozai–Lidov excited disk with a simulated disk perturbed by an interior eccentric planet. Finally, we propose two observational tests of a dust disk that can distinguish whether the dust was produced by an exterior brown dwarf or stellar companion or an interior eccentric planet.

Circumstellar and circumplanetary disks

Science.gov (United States)

Chiang, Eugene

2000-11-01

This thesis studies disks in three astrophysical contexts: (1)protoplanetary disks; (2)the Edgeworth-Kuiper Belt; and (3)planetary rings. We derive hydrostatic, radiative equilibrium models of passive protoplanetary disks surrounding T Tauri and Herbig Ae/Be stars. Each disk is encased by an optically thin layer of superheated dust grains. This layer is responsible for up to ~70% of the disk luminosity at wavelengths between ~5 and 60 μm. The heated disk flares and absorbs more stellar radiation at a given stellocentric distance than a flat disk would. Spectral energy distributions are computed and found to compare favorably with the observed flattish infrared excesses of several young stellar objects. Spectral features from dust grains in the superheated layer appear in emission if the disk is viewed nearly face-on. We present the results of a pencil-beam survey of the Kuiper Belt using the Keck 10-m telescope. Two new objects are discovered. Data from all surveys are pooled to construct the luminosity function from mR = 20 to 27. The cumulative number of objects per square degree, Σ(surface area but the largest bodies contain most of the mass. To order-of-magnitude, 0.2 M⊕ and 1 × 1010 comet progenitors lie between 30 and 50 AU. The classical Kuiper Belt appears truncated at a distance of 50 AU. We propose that rigid precession of narrow eccentric planetary rings surrounding Uranus and Saturn is maintained by a balance of forces due to ring self- gravity, planetary oblateness, and interparticle collisions. Collisional impulses play an especially dramatic role near ring edges. Pressure-induced accelerations are maximal near edges because there (1)velocity dispersions are enhanced by resonant satellite perturbations, and (2)the surface density declines steeply. Remarkably, collisional forces felt by material in the last ~100 m of a ~10 km wide ring can increase equilibrium masses up to a factor of ~100. New ring surface densities are derived which accord with

Head-Disk Interface Technology: Challenges and Approaches

Science.gov (United States)

Liu, Bo

Magnetic hard disk drive (HDD) technology is believed to be one of the most successful examples of modern mechatronics systems. The mechanical beauty of magnetic HDD includes simple but super high accuracy positioning head, positioning technology, high speed and stability spindle motor technology, and head-disk interface technology which keeps the millimeter sized slider flying over a disk surface at nanometer level slider-disk spacing. This paper addresses the challenges and possible approaches on how to further reduce the slider disk spacing whilst retaining the stability and robustness level of head-disk systems for future advanced magnetic disk drives.

An Optimal Strategy for Accurate Bulge-to-disk Decomposition of Disk Galaxies

Energy Technology Data Exchange (ETDEWEB)

Gao Hua [Department of Astronomy, School of Physics, Peking University, Beijing 100871 (China); Ho, Luis C. [Kavli Institute for Astronomy and Astrophysics, Peking University, Beijing 100871 (China)

2017-08-20

The development of two-dimensional (2D) bulge-to-disk decomposition techniques has shown their advantages over traditional one-dimensional (1D) techniques, especially for galaxies with non-axisymmetric features. However, the full potential of 2D techniques has yet to be fully exploited. Secondary morphological features in nearby disk galaxies, such as bars, lenses, rings, disk breaks, and spiral arms, are seldom accounted for in 2D image decompositions, even though some image-fitting codes, such as GALFIT, are capable of handling them. We present detailed, 2D multi-model and multi-component decomposition of high-quality R -band images of a representative sample of nearby disk galaxies selected from the Carnegie-Irvine Galaxy Survey, using the latest version of GALFIT. The sample consists of five barred and five unbarred galaxies, spanning Hubble types from S0 to Sc. Traditional 1D decomposition is also presented for comparison. In detailed case studies of the 10 galaxies, we successfully model the secondary morphological features. Through a comparison of best-fit parameters obtained from different input surface brightness models, we identify morphological features that significantly impact bulge measurements. We show that nuclear and inner lenses/rings and disk breaks must be properly taken into account to obtain accurate bulge parameters, whereas outer lenses/rings and spiral arms have a negligible effect. We provide an optimal strategy to measure bulge parameters of typical disk galaxies, as well as prescriptions to estimate realistic uncertainties of them, which will benefit subsequent decomposition of a larger galaxy sample.

An Optimal Strategy for Accurate Bulge-to-disk Decomposition of Disk Galaxies

Science.gov (United States)

Gao, Hua; Ho, Luis C.

2017-08-01

The development of two-dimensional (2D) bulge-to-disk decomposition techniques has shown their advantages over traditional one-dimensional (1D) techniques, especially for galaxies with non-axisymmetric features. However, the full potential of 2D techniques has yet to be fully exploited. Secondary morphological features in nearby disk galaxies, such as bars, lenses, rings, disk breaks, and spiral arms, are seldom accounted for in 2D image decompositions, even though some image-fitting codes, such as GALFIT, are capable of handling them. We present detailed, 2D multi-model and multi-component decomposition of high-quality R-band images of a representative sample of nearby disk galaxies selected from the Carnegie-Irvine Galaxy Survey, using the latest version of GALFIT. The sample consists of five barred and five unbarred galaxies, spanning Hubble types from S0 to Sc. Traditional 1D decomposition is also presented for comparison. In detailed case studies of the 10 galaxies, we successfully model the secondary morphological features. Through a comparison of best-fit parameters obtained from different input surface brightness models, we identify morphological features that significantly impact bulge measurements. We show that nuclear and inner lenses/rings and disk breaks must be properly taken into account to obtain accurate bulge parameters, whereas outer lenses/rings and spiral arms have a negligible effect. We provide an optimal strategy to measure bulge parameters of typical disk galaxies, as well as prescriptions to estimate realistic uncertainties of them, which will benefit subsequent decomposition of a larger galaxy sample.

An Optimal Strategy for Accurate Bulge-to-disk Decomposition of Disk Galaxies

International Nuclear Information System (INIS)

Gao Hua; Ho, Luis C.

2017-01-01

The development of two-dimensional (2D) bulge-to-disk decomposition techniques has shown their advantages over traditional one-dimensional (1D) techniques, especially for galaxies with non-axisymmetric features. However, the full potential of 2D techniques has yet to be fully exploited. Secondary morphological features in nearby disk galaxies, such as bars, lenses, rings, disk breaks, and spiral arms, are seldom accounted for in 2D image decompositions, even though some image-fitting codes, such as GALFIT, are capable of handling them. We present detailed, 2D multi-model and multi-component decomposition of high-quality R -band images of a representative sample of nearby disk galaxies selected from the Carnegie-Irvine Galaxy Survey, using the latest version of GALFIT. The sample consists of five barred and five unbarred galaxies, spanning Hubble types from S0 to Sc. Traditional 1D decomposition is also presented for comparison. In detailed case studies of the 10 galaxies, we successfully model the secondary morphological features. Through a comparison of best-fit parameters obtained from different input surface brightness models, we identify morphological features that significantly impact bulge measurements. We show that nuclear and inner lenses/rings and disk breaks must be properly taken into account to obtain accurate bulge parameters, whereas outer lenses/rings and spiral arms have a negligible effect. We provide an optimal strategy to measure bulge parameters of typical disk galaxies, as well as prescriptions to estimate realistic uncertainties of them, which will benefit subsequent decomposition of a larger galaxy sample.

Foundations of Black Hole Accretion Disk Theory

Directory of Open Access Journals (Sweden)

Marek A. Abramowicz

2013-01-01

Full Text Available This review covers the main aspects of black hole accretion disk theory. We begin with the view that one of the main goals of the theory is to better understand the nature of black holes themselves. In this light we discuss how accretion disks might reveal some of the unique signatures of strong gravity: the event horizon, the innermost stable circular orbit, and the ergosphere. We then review, from a first-principles perspective, the physical processes at play in accretion disks. This leads us to the four primary accretion disk models that we review: Polish doughnuts (thick disks, Shakura-Sunyaev (thin disks, slim disks, and advection-dominated accretion flows (ADAFs. After presenting the models we discuss issues of stability, oscillations, and jets. Following our review of the analytic work, we take a parallel approach in reviewing numerical studies of black hole accretion disks. We finish with a few select applications that highlight particular astrophysical applications: measurements of black hole mass and spin, black hole vs. neutron star accretion disks, black hole accretion disk spectral states, and quasi-periodic oscillations (QPOs.

Foundations of Black Hole Accretion Disk Theory.

Science.gov (United States)

Abramowicz, Marek A; Fragile, P Chris

2013-01-01

This review covers the main aspects of black hole accretion disk theory. We begin with the view that one of the main goals of the theory is to better understand the nature of black holes themselves. In this light we discuss how accretion disks might reveal some of the unique signatures of strong gravity: the event horizon, the innermost stable circular orbit, and the ergosphere. We then review, from a first-principles perspective, the physical processes at play in accretion disks. This leads us to the four primary accretion disk models that we review: Polish doughnuts (thick disks), Shakura-Sunyaev (thin) disks, slim disks, and advection-dominated accretion flows (ADAFs). After presenting the models we discuss issues of stability, oscillations, and jets. Following our review of the analytic work, we take a parallel approach in reviewing numerical studies of black hole accretion disks. We finish with a few select applications that highlight particular astrophysical applications: measurements of black hole mass and spin, black hole vs. neutron star accretion disks, black hole accretion disk spectral states, and quasi-periodic oscillations (QPOs).

Relativistic, accreting disks

International Nuclear Information System (INIS)

Abramowicz, M.A; Jaroszynski, M.; Sikora, M.

1978-01-01

An analytic theory of the hydrodynamical structure of accreting disks (without self-gravitation but with pressure) orbiting around and axially symmetric, stationary, compact body (e.g. black hole) is presented. The inner edge of the marginally stable accreting disk (i.e. disk with constant angular momentum density) has a sharp cusp located on the equatorial plane between rsub(ms) and rsub(mb). The existence of the cusp is also typical for any angular momentum distribution. The physical importance of the cusp follows from the close analogy with the case of a close binary system (L 1 Lagrange point on the Roche lobe). The existence of the cusp is thus a crucial phenomenon in such problems as boundary condition for the viscous stresses, accretion rate etc. (orig.) [de

CT recognition of lateral lumbar disk herniation

International Nuclear Information System (INIS)

Williams, A.L.; Haughton, V.M.; Daniels, D.L.; Thornton, R.S.

1982-01-01

Although computed tomography (CT) has been shown to be useful in diagnosing posterolateral and central lumbar disk herniations, its effectiveness in demonstrating lateral herniated disks has not been emphasized. The myelographic recognition of those herniations may be difficult because root sheaths or dural sacs may not be deformed. A total of 274 CT scans interpreted as showing lumbar disk herniation was reviewed. Fourteen (5%) showed a lateral disk herniation. The CT features of a lateral herniated disk included: (1) focal protrusion of the disk margin within or lateral to the intervertebral foramen: (2) displacement of epidural fat within the intervertebral foramen; (3) absence of dural sac deformity; and (4) soft-tissue mass within or lateral to the intervertebral foramen. Because it can image the disk margin and free disk fragments irrespective of dural sac or root sheath deformity, CT may be more effective than myelography for demonstrating the presence and extent of lateral disk herniation

Grain surface chemistry in protoplanetary disks

International Nuclear Information System (INIS)

Reboussin, Laura

2015-01-01

Planetary formation occurs in the protoplanetary disks of gas and dust. Although dust represents only 1% of the total disk mass, it plays a fundamental role in disk chemical evolution since it acts as a catalyst for the formation of molecules. Understanding this chemistry is therefore essential to determine the initial conditions from which planets form. During my thesis, I studied grain-surface chemistry and its impact on the chemical evolution of molecular cloud, initial condition for disk formation, and protoplanetary disk. Thanks to numerical simulations, using the gas-grain code Nautilus, I showed the importance of diffusion reactions and gas-grain interactions for the abundances of gas-phase species. Model results combined with observations also showed the effects of the physical structure (in temperature, density, AV) on the molecular distribution in disks. (author)

The DiskMass Survey. II. Error Budget

Science.gov (United States)

Bershady, Matthew A.; Verheijen, Marc A. W.; Westfall, Kyle B.; Andersen, David R.; Swaters, Rob A.; Martinsson, Thomas

2010-06-01

We present a performance analysis of the DiskMass Survey. The survey uses collisionless tracers in the form of disk stars to measure the surface density of spiral disks, to provide an absolute calibration of the stellar mass-to-light ratio (Υ_{*}), and to yield robust estimates of the dark-matter halo density profile in the inner regions of galaxies. We find that a disk inclination range of 25°-35° is optimal for our measurements, consistent with our survey design to select nearly face-on galaxies. Uncertainties in disk scale heights are significant, but can be estimated from radial scale lengths to 25% now, and more precisely in the future. We detail the spectroscopic analysis used to derive line-of-sight velocity dispersions, precise at low surface-brightness, and accurate in the presence of composite stellar populations. Our methods take full advantage of large-grasp integral-field spectroscopy and an extensive library of observed stars. We show that the baryon-to-total mass fraction ({F}_bar) is not a well-defined observational quantity because it is coupled to the halo mass model. This remains true even when the disk mass is known and spatially extended rotation curves are available. In contrast, the fraction of the rotation speed supplied by the disk at 2.2 scale lengths (disk maximality) is a robust observational indicator of the baryonic disk contribution to the potential. We construct the error budget for the key quantities: dynamical disk mass surface density (Σdyn), disk stellar mass-to-light ratio (Υ^disk_{*}), and disk maximality ({F}_{*,max}^disk≡ V^disk_{*,max}/ V_c). Random and systematic errors in these quantities for individual galaxies will be ~25%, while survey precision for sample quartiles are reduced to 10%, largely devoid of systematic errors outside of distance uncertainties.

A COMMON SOURCE OF ACCRETION DISK TILT

International Nuclear Information System (INIS)

Montgomery, M. M.; Martin, E. L.

2010-01-01

Many different system types retrogradely precess, and retrograde precession could be from a tidal torque by the secondary on a misaligned accretion disk. However, a source that causes and maintains disk tilt is unknown. In this work, we show that accretion disks can tilt due to a force called lift. Lift results from differing gas stream supersonic speeds over and under an accretion disk. Because lift acts at the disk's center of pressure, a torque is applied around a rotation axis passing through the disk's center of mass. The disk responds to lift by pitching around the disk's line of nodes. If the gas stream flow ebbs, then lift also ebbs and the disk attempts to return to its original orientation. To first approximation, lift does not depend on magnetic fields or radiation sources but does depend on the mass and the surface area of the disk. Also, for disk tilt to be initiated, a minimum mass transfer rate must be exceeded. For example, a 10 -11 M sun disk around a 0.8 M sun compact central object requires a mass transfer rate greater than ∼ 8 x 10 -11 M sun yr -1 , a value well below the known mass transfer rates in cataclysmic variable dwarf novae systems that retrogradely precess and exhibit negative superhumps in their light curves and a value well below mass transfer rates in protostellar-forming systems.

Covering and piercing disks with two centers

KAUST Repository

Ahn, Heekap; Kim, Sangsub; Knauer, Christian; Schlipf, Lena; Shin, Chansu; Vigneron, Antoine E.

2013-01-01

We give exact and approximation algorithms for two-center problems when the input is a set D of disks in the plane. We first study the problem of finding two smallest congruent disks such that each disk in D intersects one of these two disks. Then we study the problem of covering the set D by two smallest congruent disks. © 2012 Elsevier B.V.

Covering and piercing disks with two centers

KAUST Repository

Ahn, Heekap

2013-04-01

We give exact and approximation algorithms for two-center problems when the input is a set D of disks in the plane. We first study the problem of finding two smallest congruent disks such that each disk in D intersects one of these two disks. Then we study the problem of covering the set D by two smallest congruent disks. © 2012 Elsevier B.V.

HERSCHEL OBSERVATIONS OF THE T CHA TRANSITION DISK: CONSTRAINING THE OUTER DISK PROPERTIES

OpenAIRE

Cieza, Lucas A.; Olofsson, Johan; Harvey, Paul M.; Pinte, Christophe; Merin, Bruno; Augereau, Jean-Charles; Evans, Neal J., II; Najita, Joan; Henning, Thomas; Menard, Francois

2011-01-01

T Cha is a nearby (d = 100 pc) transition disk known to have an optically thin gap separating optically thick inner and outer disk components. Huelamo et al. (2011) recently reported the presence of a low-mass object candidate within the gap of the T Cha disk, giving credence to the suspected planetary origin of this gap. Here we present the Herschel photometry (70, 160, 250, 350, and 500 micron) of T Cha from the "Dust, Ice, and Gas in Time" (DIGIT) Key Program, which bridges the wavelength ...

EMBEDDED PROTOSTELLAR DISKS AROUND (SUB-)SOLAR STARS. II. DISK MASSES, SIZES, DENSITIES, TEMPERATURES, AND THE PLANET FORMATION PERSPECTIVE

International Nuclear Information System (INIS)

Vorobyov, Eduard I.

2011-01-01

We present basic properties of protostellar disks in the embedded phase of star formation (EPSF), which is difficult to probe observationally using available observational facilities. We use numerical hydrodynamics simulations of cloud core collapse and focus on disks formed around stars in the 0.03-1.0 M sun mass range. Our obtained disk masses scale near-linearly with the stellar mass. The mean and median disk masses in the Class 0 and I phases (M mean d,C0 = 0.12 M sun , M mdn d,C0 = 0.09 M sun and M mean d,CI = 0.18 M sun , M mdn d,CI = 0.15 M sun , respectively) are greater than those inferred from observations by (at least) a factor of 2-3. We demonstrate that this disagreement may (in part) be caused by the optically thick inner regions of protostellar disks, which do not contribute to millimeter dust flux. We find that disk masses and surface densities start to systematically exceed that of the minimum mass solar nebular for objects with stellar mass as low as M * = 0.05-0.1 M sun . Concurrently, disk radii start to grow beyond 100 AU, making gravitational fragmentation in the disk outer regions possible. Large disk masses, surface densities, and sizes suggest that giant planets may start forming as early as in the EPSF, either by means of core accretion (inner disk regions) or direct gravitational instability (outer disk regions), thus breaking a longstanding stereotype that the planet formation process begins in the Class II phase.

TOWARD A GLOBAL EVOLUTIONARY MODEL OF PROTOPLANETARY DISKS

Energy Technology Data Exchange (ETDEWEB)

Bai, Xue-Ning, E-mail: xbai@cfa.harvard.edu [Institute for Theory and Computation, Harvard-Smithsonian Center for Astrophysics, 60 Garden St., MS-51, Cambridge, MA 02138 (United States)

2016-04-20

A global picture of the evolution  of protoplanetary disks (PPDs) is key to understanding almost every aspect of planet formation, where standard α-disk models have been continually employed for their simplicity. In the meantime, disk mass loss has been conventionally attributed to photoevaporation, which controls disk dispersal. However, a paradigm shift toward accretion driven by magnetized disk winds has taken place in recent years, thanks to studies of non-ideal magnetohydrodynamic effects in PPDs. I present a framework of global PPD evolution aiming to incorporate these advances, highlighting the role of wind-driven accretion and wind mass loss. Disk evolution is found to be largely dominated by wind-driven processes, and viscous spreading is suppressed. The timescale of disk evolution is controlled primarily by the amount of external magnetic flux threading the disks, and how rapidly the disk loses the flux. Rapid disk dispersal can be achieved if the disk is able to hold most of its magnetic flux during the evolution. In addition, because wind launching requires a sufficient level of ionization at the disk surface (mainly via external far-UV (FUV) radiation), wind kinematics is also affected by the FUV penetration depth and disk geometry. For a typical disk lifetime of a few million years, the disk loses approximately the same amount of mass through the wind as through accretion onto the protostar, and most of the wind mass loss proceeds from the outer disk via a slow wind. Fractional wind mass loss increases with increasing disk lifetime. Significant wind mass loss likely substantially enhances the dust-to-gas mass ratio and promotes planet formation.

TOWARD A GLOBAL EVOLUTIONARY MODEL OF PROTOPLANETARY DISKS

International Nuclear Information System (INIS)

Bai, Xue-Ning

2016-01-01

A global picture of the evolution  of protoplanetary disks (PPDs) is key to understanding almost every aspect of planet formation, where standard α-disk models have been continually employed for their simplicity. In the meantime, disk mass loss has been conventionally attributed to photoevaporation, which controls disk dispersal. However, a paradigm shift toward accretion driven by magnetized disk winds has taken place in recent years, thanks to studies of non-ideal magnetohydrodynamic effects in PPDs. I present a framework of global PPD evolution aiming to incorporate these advances, highlighting the role of wind-driven accretion and wind mass loss. Disk evolution is found to be largely dominated by wind-driven processes, and viscous spreading is suppressed. The timescale of disk evolution is controlled primarily by the amount of external magnetic flux threading the disks, and how rapidly the disk loses the flux. Rapid disk dispersal can be achieved if the disk is able to hold most of its magnetic flux during the evolution. In addition, because wind launching requires a sufficient level of ionization at the disk surface (mainly via external far-UV (FUV) radiation), wind kinematics is also affected by the FUV penetration depth and disk geometry. For a typical disk lifetime of a few million years, the disk loses approximately the same amount of mass through the wind as through accretion onto the protostar, and most of the wind mass loss proceeds from the outer disk via a slow wind. Fractional wind mass loss increases with increasing disk lifetime. Significant wind mass loss likely substantially enhances the dust-to-gas mass ratio and promotes planet formation

Relativistic, accreting disks

Energy Technology Data Exchange (ETDEWEB)

Abramowicz, M A; Jaroszynski, M; Sikora, M [Polska Akademia Nauk, Warsaw

1978-02-01

An analytic theory of the hydrodynamical structure of accreting disks (without self-gravitation but with pressure) orbiting around an axially symmetric, stationary, compact body (e.g. black hole) is presented. The inner edge of the marginally stable accreting disk (i.e. disk with constant angular momentum density) has a sharp cusp located on the equatorial plane between r/sub ms/ and r/sub mb/. The existence of the cusp is also typical for any angular momentum distribution. The physical importance of the cusp follows from the close analogy with the case of a close binary system (L/sub 1/ Lagrange point on the Roche lobe). The existence of the cusp is thus a crucial phenomenon in such problems as boundary condition for the viscous stresses, accretion rate, etc.

IBM 3390 Hard Disk Platter

CERN Multimedia

1991-01-01

The 3390 disks rotated faster than those in the previous model 3380. Faster disk rotation reduced rotational delay (ie. the time required for the correct area of the disk surface to move to the point where data could be read or written). In the 3390's initial models, the average rotational delay was reduced to 7.1 milliseconds from 8.3 milliseconds for the 3380 family.

Formation of Close-in Super-Earths in an Evolving Disk Due to Disk Winds

Science.gov (United States)

Ogihara, Masahiro; Kokubo, Eiichiro; Suzuki, Takeru; Morbidelli, Alessandro

2018-04-01

Planets with masses larger than Mars mass undergo rapid inward migration (type I migration) in a standard protoplanetary disk. Recent magnetohydrodynamical simulations revealed the presence of magnetically-driven disk winds, which would alter the disk profile and the type I migration in the close-in region (rEarths can be reproduced by simulations. We find that the type I migration is significantly suppressed in a disk with flat surface density profile. After planetary embryos undergo slow inward migration, they are captured in a resonant chain. The resonant chain undergoes late orbital instability during the gas depletion, leading to a non-resonant configuration. We also find that observed distributions of close-in super-Earths (e.g., period ratio, mass ratio) can be reproduced by results of simulations.

Hydrogen Cyanide In Protoplanetary Disks

Science.gov (United States)

Walker, Ashley L.; Oberg, Karin; Cleeves, L. Ilsedore

2018-01-01

The chemistry behind star and planet formation is extremely complex and important in the formation of habitable planets. Life requires molecules containing carbon, oxygen, and importantly, nitrogen. Hydrogen cyanide, or HCN, one of the main interstellar nitrogen carriers, is extremely dangerous here on Earth. However, it could be used as a vital tool for tracking the chemistry of potentially habitable planets. As we get closer to identifying other habitable planets, we must understand the beginnings of how those planets are formed in the early protoplanetary disk. This project investigates HCN chemistry in different locations in the disk, and what this might mean for forming planets at different distances from the star. HCN is a chemically diverse molecule. It is connected to the formation for other more complex molecules and is commonly used as a nitrogen tracer. Using computational chemical models we look at how the HCN abundance changes at different locations. We use realistic and physically motivated conditions for the gas in the protoplanetary disk: temperature, density, and radiation (UV flux). We analyze the reaction network, formation, and destruction of HCN molecules in the disk environment. The disk environment informs us about stability of habitable planets that are created based on HCN molecules. We reviewed and compared the difference in the molecules with a variety of locations in the disk and ultimately giving us a better understanding on how we view protoplanetary disks.

CO Gas Inside the Protoplanetary Disk Cavity in HD 142527: Disk Structure from ALMA

OpenAIRE

Perez, S.; Casassus, S.; Ménard, F.; Roman, P.; van der Plas, G.; Cieza, L.; Pinte, C.; Christiaens, Valentin; Hales, A. S.

2014-01-01

Inner cavities and annular gaps in circumstellar disks are possible signposts of giant planet formation. The young star HD 142527 hosts a massive protoplanetary disk with a large cavity that extends up to 140 AU from the central star, as seen in continuum images at infrared and millimeter wavelengths. Estimates of the survival of gas inside disk cavities are needed to discriminate between clearing scenarios. We present a spatially and spectrally resolved carbon monoxide isotopologue 2-1 line ...

The Tilt between Acretion Disk and Stellar Disk Shiyin Shen1,2 ...

Indian Academy of Sciences (India)

80 Nandan Road, Shanghai 200030, China. 2Key Lab for Astrophysics, Shanghai 200234, China. ∗ e-mail: ssy@shao.ac.cn. Abstract. The orientations .... shows the model prediction from the stellar dust model (section 5). 4. Result: The tilt between the accretion disk and stellar disk. We parameterize the inclinations of the ...

Cold disks : Spitzer spectroscopy of disks around young stars with large gaps

NARCIS (Netherlands)

Blake, G. A.; Dullemond, C. P.; Merin, B.; Augereau, J. C.; Boogert, A. C. A.; Evans, N. J.; Geers, V. C.; Lahuis, F.; Kessler-Silacci, J. E.; Pontoppidan, K. M.; van Dishoeck, E. F.; Brown, J.M.

2007-01-01

We have identified four circumstellar disks with a deficit of dust emission from their inner 15-50 AU. All four stars have F-G spectral type and were uncovered as part of the Spitzer Space Telescope "Cores to Disks" Legacy Program Infrared Spectrograph (IRS) first-look survey of similar to 100 pre -

Covering and piercing disks with two centers

KAUST Repository

Ahn, Heekap; Kim, Sangsub; Knauer, Christian; Schlipf, Lena; Shin, Chansu; Vigneron, Antoine E.

2011-01-01

We consider new versions of the two-center problem where the input consists of a set D of disks in the plane. We first study the problem of finding two smallest congruent disks such that each disk in intersects one of these two disks. Then we study the problem of covering the set D by two smallest congruent disks. We give exact and approximation algorithms for these versions. © 2011 Springer-Verlag.

Verbatim Floppy Disk

CERN Multimedia

1976-01-01

Introduced under the name "Verbatim", Latin for "literally", these disks that sized more than 5¼ inches have become almost universal on dedicated word processing systems and personal computers. This format was replaced more slowly by the 3½-inch format, introduced for the first time in 1982. Compared to today, these large format disks stored very little data. In reality, they could only contain a few pages of text.

Astrophysical disks Collective and Stochastic Phenomena

CERN Document Server

Fridman, Alexei M; Kovalenko, Ilya G

2006-01-01

The book deals with collective and stochastic processes in astrophysical discs involving theory, observations, and the results of modelling. Among others, it examines the spiral-vortex structure in galactic and accretion disks , stochastic and ordered structures in the developed turbulence. It also describes sources of turbulence in the accretion disks, internal structure of disk in the vicinity of a black hole, numerical modelling of Be envelopes in binaries, gaseous disks in spiral galaxies with shock waves formation, observation of accretion disks in a binary system and mass distribution of luminous matter in disk galaxies. The editors adaptly brought together collective and stochastic phenomena in the modern field of astrophysical discs, their formation, structure, and evolution involving the methodology to deal with, the results of observation and modelling, thereby advancing the study in this important branch of astrophysics and benefiting Professional Researchers, Lecturers, and Graduate Students.

Gravitational Instabilities in Circumstellar Disks

Science.gov (United States)

Kratter, Kaitlin; Lodato, Giuseppe

2016-09-01

Star and planet formation are the complex outcomes of gravitational collapse and angular momentum transport mediated by protostellar and protoplanetary disks. In this review, we focus on the role of gravitational instability in this process. We begin with a brief overview of the observational evidence for massive disks that might be subject to gravitational instability and then highlight the diverse ways in which the instability manifests itself in protostellar and protoplanetary disks: the generation of spiral arms, small-scale turbulence-like density fluctuations, and fragmentation of the disk itself. We present the analytic theory that describes the linear growth phase of the instability supplemented with a survey of numerical simulations that aim to capture the nonlinear evolution. We emphasize the role of thermodynamics and large-scale infall in controlling the outcome of the instability. Despite apparent controversies in the literature, we show a remarkable level of agreement between analytic predictions and numerical results. In the next part of our review, we focus on the astrophysical consequences of the instability. We show that the disks most likely to be gravitationally unstable are young and relatively massive compared with their host star, Md/M*≥0.1. They will develop quasi-stable spiral arms that process infall from the background cloud. Although instability is less likely at later times, once infall becomes less important, the manifestations of the instability are more varied. In this regime, the disk thermodynamics, often regulated by stellar irradiation, dictates the development and evolution of the instability. In some cases the instability may lead to fragmentation into bound companions. These companions are more likely to be brown dwarfs or stars than planetary mass objects. Finally, we highlight open questions related to the development of a turbulent cascade in thin disks and the role of mode-mode coupling in setting the maximum angular

Development of Powered Disk Type Sugar Cane Stubble Saver

Directory of Open Access Journals (Sweden)

Radite P.A.S.

2009-04-01

Full Text Available The objective of this research was to design, fabricate and test a prototype of sugar cane stubble saver based on powered disk mechanism. In this research, a heavy duty disk plow or disk harrow was used as a rotating knife to cut the sugarcane stubble. The parabolic disk was chosen because it is proven reliable as soil working tools and it is available in the market as spare part of disk plow or disk harrow unit. The prototype was mounted on the four wheel tractor’s three point hitch, and powered by PTO of the tractor. Two kinds of disks were used in these experiments, those were disk with regular edge or plain disk and disk with scalloped edge or scalloped disk. Both disks had diameter of 28 inch. Results of field test showed that powered disk mechanism could satisfy cut sugar cane’s stubble. However, scalloped disk type gave smoother stubble cuts compared to that of plain disk. Plain disk type gave broken stubble cut. Higher rotation (1000 rpm resulted better cuts as compared to lower rotation (500 rpm both either on plain disk and scalloped disk. The developed prototype could work below the soil surface at depth of 5 to 10 cm. With tilt angle setting 20O and disk angle 45O the width of cut was about 25 cm.

Accretion in Radiative Equipartition (AiRE) Disks

Energy Technology Data Exchange (ETDEWEB)

Yazdi, Yasaman K.; Afshordi, Niayesh, E-mail: yyazdi@pitp.ca, E-mail: nafshordi@pitp.ca [Perimeter Institute for Theoretical Physics, 31 Caroline Street N, Waterloo, ON N2L 2Y5 (Canada)

2017-07-01

Standard accretion disk theory predicts that the total pressure in disks at typical (sub-)Eddington accretion rates becomes radiation pressure dominated. However, radiation pressure dominated disks are thermally unstable. Since these disks are observed in approximate steady state over the instability timescale, our accretion models in the radiation-pressure-dominated regime (i.e., inner disk) need to be modified. Here, we present a modification to the Shakura and Sunyaev model, where the radiation pressure is in equipartition with the gas pressure in the inner region. We call these flows accretion in radiative equipartition (AiRE) disks. We introduce the basic features of AiRE disks and show how they modify disk properties such as the Toomre parameter and the central temperature. We then show that the accretion rate of AiRE disks is limited from above and below, by Toomre and nodal sonic point instabilities, respectively. The former leads to a strict upper limit on the mass of supermassive black holes as a function of cosmic time (and spin), while the latter could explain the transition between hard and soft states of X-ray binaries.

Modeling Protoplanetary Disks

Science.gov (United States)

Holman, Megan; Tubbs, Drake; Keller, L. D.

2018-01-01

Using spectra models with known parameters and comparing them to spectra gathered from real systems is often the only ways to find out what is going on in those real systems. This project uses the modeling programs of RADMC-3D to generate model spectra for systems containing protoplanetary disks. The parameters can be changed to simulate protoplanetary disks in different stages of planet formation, with different sized gaps in different areas of the disks, as well as protoplanetary disks that contain different types of dust. We are working on producing a grid of models that all have different variations in the parameters in order to generate a miniature database to use for comparisons to gathered spectra. The spectra produced from these simulations will be compared to spectra that have been gathered from systems in the Small Magellanic cloud in order to find out the contents and stage of development of that system. This allows us to see if and how planets are forming in the Small Magellanic cloud, a region which has much less metallicity than our own galaxy. The data we gather from comparisons between the model spectra and the spectra of systems in the Small Magellanic Cloud can then be applied to how planets may have formed in the early universe.

The Fabulous Four Debris Disks

Science.gov (United States)

Werner, Michael; Stapelfeldt, Karl

2004-09-01

This program is a comprehensive study of the four bright debris disks that were spatially resolved by IRAS: Beta Pictoris, Epsilon Eridani, Fomalhaut, and Vega. All SIRTF instruments and observing modes will be used. The program has three major objectives: (1) Study of the disk spatial structure from MIPS and IRAC imaging; (2) Study of the dust grain composition using the IRS and MIPS SED mode; and (3) companion searches using IRAC. The data from this program should lead to a detailed understanding of these four systems, and will provide a foundation for understanding all of the debris disks to be studied with SIRTF. Images and spectra will be compared with models for disk structure and dust properties. Dynamical features indicative of substellar companions' effects on the disks will be searched for. This program will require supporting observations of PSF stars, some of which have been included explicitly. In the majority of cases, the spectral observations require a preferred orientation to align the slits along the disk position angles. Detector saturation issues are still being worked for this program, and will lead to AOR modifications in subsequent submissions. The results from this program will be analyzed collaboratively by the IRAC, IRS, and MIPS teams and by general GTOs Jura and Werner.

THE VLA VIEW OF THE HL TAU DISK: DISK MASS, GRAIN EVOLUTION, AND EARLY PLANET FORMATION

Energy Technology Data Exchange (ETDEWEB)

Carrasco-González, Carlos; Rodríguez, Luis F.; Galván-Madrid, Roberto [Instituto de Radioastronomía y Astrofísica UNAM, Apartado Postal 3-72 (Xangari), 58089 Morelia, Michoacán, México (Mexico); Henning, Thomas; Linz, Hendrik; Birnstiel, Til; Boekel, Roy van; Klahr, Hubert [Max-Planck-Institut für Astronomie Heidelberg, Königstuhl 17, D-69117 Heidelberg (Germany); Chandler, Claire J.; Pérez, Laura [National Radio Astronomy Observatory, P.O. Box O, 1003 Lopezville Road, Socorro, NM 87801-0387 (United States); Anglada, Guillem; Macias, Enrique; Osorio, Mayra [Instituto de Astrofísica de Andalucía (CSIC), Apartado 3004, E-18080 Granada (Spain); Flock, Mario [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Menten, Karl [Jansky Fellow of the National Radio Astronomy Observatory (United States); Testi, Leonardo [European Southern Observatory, Karl-Schwarzschild-Str. 2, D-85748 Garching bei München (Germany); Torrelles, José M. [Institut de Ciències de l’Espai (CSIC-IEEC) and Institut de Ciències del Cosmos (UB-IEEC), Martí i Franquès 1, E-08028 Barcelona (Spain); Zhu, Zhaohuan, E-mail: c.carrasco@crya.unam.mx, E-mail: l.rodriguez@crya.unam.mx, E-mail: r.galvan@crya.unam.mx, E-mail: henning@mpia.de, E-mail: linz@mpia.de [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States)

2016-04-10

The first long-baseline ALMA campaign resolved the disk around the young star HL Tau into a number of axisymmetric bright and dark rings. Despite the very young age of HL Tau, these structures have been interpreted as signatures for the presence of (proto)planets. The ALMA images triggered numerous theoretical studies based on disk–planet interactions, magnetically driven disk structures, and grain evolution. Of special interest are the inner parts of disks, where terrestrial planets are expected to form. However, the emission from these regions in HL Tau turned out to be optically thick at all ALMA wavelengths, preventing the derivation of surface density profiles and grain-size distributions. Here, we present the most sensitive images of HL Tau obtained to date with the Karl G. Jansky Very Large Array at 7.0 mm wavelength with a spatial resolution comparable to the ALMA images. At this long wavelength, the dust emission from HL Tau is optically thin, allowing a comprehensive study of the inner disk. We obtain a total disk dust mass of (1–3) × 10{sup −3} M {sub ⊙}, depending on the assumed opacity and disk temperature. Our optically thin data also indicate fast grain growth, fragmentation, and formation of dense clumps in the inner densest parts of the disk. Our results suggest that the HL Tau disk may be actually in a very early stage of planetary formation, with planets not already formed in the gaps but in the process of future formation in the bright rings.

THE VLA VIEW OF THE HL TAU DISK: DISK MASS, GRAIN EVOLUTION, AND EARLY PLANET FORMATION

International Nuclear Information System (INIS)

Carrasco-González, Carlos; Rodríguez, Luis F.; Galván-Madrid, Roberto; Henning, Thomas; Linz, Hendrik; Birnstiel, Til; Boekel, Roy van; Klahr, Hubert; Chandler, Claire J.; Pérez, Laura; Anglada, Guillem; Macias, Enrique; Osorio, Mayra; Flock, Mario; Menten, Karl; Testi, Leonardo; Torrelles, José M.; Zhu, Zhaohuan

2016-01-01

The first long-baseline ALMA campaign resolved the disk around the young star HL Tau into a number of axisymmetric bright and dark rings. Despite the very young age of HL Tau, these structures have been interpreted as signatures for the presence of (proto)planets. The ALMA images triggered numerous theoretical studies based on disk–planet interactions, magnetically driven disk structures, and grain evolution. Of special interest are the inner parts of disks, where terrestrial planets are expected to form. However, the emission from these regions in HL Tau turned out to be optically thick at all ALMA wavelengths, preventing the derivation of surface density profiles and grain-size distributions. Here, we present the most sensitive images of HL Tau obtained to date with the Karl G. Jansky Very Large Array at 7.0 mm wavelength with a spatial resolution comparable to the ALMA images. At this long wavelength, the dust emission from HL Tau is optically thin, allowing a comprehensive study of the inner disk. We obtain a total disk dust mass of (1–3) × 10 −3 M ⊙ , depending on the assumed opacity and disk temperature. Our optically thin data also indicate fast grain growth, fragmentation, and formation of dense clumps in the inner densest parts of the disk. Our results suggest that the HL Tau disk may be actually in a very early stage of planetary formation, with planets not already formed in the gaps but in the process of future formation in the bright rings

CONSTRAINTS ON COMPTON-THICK WINDS FROM BLACK HOLE ACCRETION DISKS: CAN WE SEE THE INNER DISK?

International Nuclear Information System (INIS)

Reynolds, Christopher S.

2012-01-01

Strong evidence is emerging that winds can be driven from the central regions of accretion disks in both active galactic nuclei and Galactic black hole binaries. Direct evidence for highly ionized, Compton-thin inner-disk winds comes from observations of blueshifted (v ∼ 0.05-0.1c) iron-K X-ray absorption lines. However, it has been suggested that the inner regions of black hole accretion disks can also drive Compton-thick winds—such winds would enshroud the inner disk, preventing us from seeing direct signatures of the accretion disk (i.e., the photospheric thermal emission, or the Doppler/gravitationally broadened iron Kα line). Here, we show that, provided the source is sub-Eddington, the well-established wind-driving mechanisms fail to launch a Compton-thick wind from the inner disk. For the accelerated region of the wind to be Compton-thick, the momentum carried in the wind must exceed the available photon momentum by a factor of at least 2/λ, where λ is the Eddington ratio of the source, ruling out radiative acceleration unless the source is very close to the Eddington limit. Compton-thick winds also carry large mass fluxes, and a consideration of the connections between the wind and the disk shows this to be incompatible with magneto-centrifugal driving. Finally, thermal driving of the wind is ruled out on the basis of the large Compton radii that typify black hole systems. In the absence of some new acceleration mechanisms, we conclude that the inner regions of sub-Eddington accretion disks around black holes are indeed naked.

PLANETESIMAL AND PROTOPLANET DYNAMICS IN A TURBULENT PROTOPLANETARY DISK: IDEAL UNSTRATIFIED DISKS

International Nuclear Information System (INIS)

Yang, Chao-Chin; Mac Low, Mordecai-Mark; Menou, Kristen

2009-01-01

The dynamics of planetesimals and planetary cores may be strongly influenced by density perturbations driven by magneto-rotational turbulence in their natal protoplanetary gas disks. Using the local shearing box approximation, we perform numerical simulations of planetesimals moving as massless particles in a turbulent, magnetized, unstratified gas disk. Our fiducial disk model shows turbulent accretion characterized by a Shakura-Sunyaev viscosity parameter of α ∼ 10 -2 , with rms density perturbations of ∼10%. We measure the statistical evolution of particle orbital properties in our simulations including mean radius, eccentricity, and velocity dispersion. We confirm random walk growth in time of all three properties, the first time that this has been done with direct orbital integration in a local model. We find that the growth rate increases with the box size used at least up to boxes of eight scale heights in horizontal size. However, even our largest boxes show velocity dispersions sufficiently low that collisional destruction of planetesimals should be unimportant in the inner disk throughout its lifetime. Our direct integrations agree with earlier torque measurements showing that type I migration dominates over diffusive migration by stochastic torques for most objects in the planetary core and terrestrial planet mass range. Diffusive migration remains important for objects in the mass range of kilometer-sized planetesimals. Discrepancies in the derived magnitude of turbulence between local and global simulations of magneto-rotationally unstable disks remains an open issue, with important consequences for planet formation scenarios.

Circumstellar Gas in Young Planetary Debris Disks

Science.gov (United States)

Roberge, A.

Circumstellar (CS) disks orbiting young stars fall into two categories: primordial disks, composed of unprocessed interstellar dust and gas, and debris disks, produced by the destruction of solid planetary bodies. In the first class, the most abundant gas is H_2; in the second, it appears that the H_2 gas has disappeared, possibly through incorporation into gas giant planets. The lifetime of H_2 gas in a CS disk is therefore of great importance, as it dictates the timescale for the formation of giant planets. FUSE observations of H_2 in CS disk systems have shown that FUV absorption spectroscopy may sensitively probe for small amounts of gas along the line of sight to the star. Most importantly, the FUSE non-detection of H_2 gas in the Beta Pictoris disk suggests that the primordial gas lifetime is less than about 12 Myr, and that gas giant planets must form very quickly. However, this suggestion is based on one system, and needs to be tested in additional systems with a range of ages, especially since there are indications that age is not the only factor in the evolution of a CS disk. We propose for FUSE observations of 3 additional debris disk systems, Fomalhaut, HD3003, and HD2884. Fomalhaut is an intermediate age debris disk, one of the Fabulous Four CS disks first discovered in 1984. The other two disks are younger, with ages similar to that of Beta Pic. All three stars are brighter in the FUV than Beta Pic, permitting us to sensitively probe for traces of H_2 gas. We will also measure the amount of secondary atomic gas produced from planetary bodies in these disks, in an effort to understand the entire evolution of CS gas in young planetary systems.

A New M Dwarf Debris Disk Candidate in a Young Moving Group Discovered with Disk Detective

Science.gov (United States)

Silverberg, Steven M.; Kuchner, Marc J.; Wisniewski, John P.; Gagne, Jonathan; Bans, Alissa S.; Bhattacharjee, Shambo; Currie, Thayne R.; Debes, John R.; Biggs, Joseph R; Bosch, Milton

2016-01-01

We used the Disk Detective citizen science project and the BANYAN II Bayesian analysis tool to identify a new candidate member of a nearby young association with infrared excess. WISE J080822.18-644357.3, an M5.5-type debris disk system with significant excess at both 12 and 22 microns, is a likely member (approx.90% BANYAN II probability) of the approx.45 Myr old Carina association. Since this would be the oldest M dwarf debris disk detected in a moving group, this discovery could be an important constraint on our understanding of M dwarf debris disk evolution.

Circumstellar disks around binary stars in Taurus

International Nuclear Information System (INIS)

Akeson, R. L.; Jensen, E. L. N.

2014-01-01

We have conducted a survey of 17 wide (>100 AU) young binary systems in Taurus with the Atacama Large Millimeter Array (ALMA) at two wavelengths. The observations were designed to measure the masses of circumstellar disks in these systems as an aid to understanding the role of multiplicity in star and planet formation. The ALMA observations had sufficient resolution to localize emission within the binary system. Disk emission was detected around all primaries and 10 secondaries, with disk masses as low as 10 –4 M ☉ . We compare the properties of our sample to the population of known disks in Taurus and find that the disks from this binary sample match the scaling between stellar mass and millimeter flux of F mm ∝M ∗ 1.5--2.0 to within the scatter found in previous studies. We also compare the properties of the primaries to those of the secondaries and find that the secondary/primary stellar and disk mass ratios are not correlated; in three systems, the circumsecondary disk is more massive than the circumprimary disk, counter to some theoretical predictions.

MIGRATION TRAPS IN DISKS AROUND SUPERMASSIVE BLACK HOLES

International Nuclear Information System (INIS)

Bellovary, Jillian M.; Low, Mordecai-Mark Mac; McKernan, Barry; Ford, K. E. Saavik

2016-01-01

Accretion disks around supermassive black holes (SMBHs) in active galactic nuclei (AGNs) contain stars, stellar mass black holes, and other stellar remnants, which perturb the disk gas gravitationally. The resulting density perturbations exert torques on the embedded masses causing them to migrate through the disk in a manner analogous to planets in protoplanetary disks. We determine the strength and direction of these torques using an empirical analytic description dependent on local disk gradients, applied to two different analytic, steady-state disk models of SMBH accretion disks. We find that there are radii in such disks where the gas torque changes sign, trapping migrating objects. Our analysis shows that major migration traps generally occur where the disk surface density gradient changes sign from positive to negative, around 20–300R g , where R g  = 2GM/c 2 is the Schwarzschild radius. At these traps, massive objects in the AGN disk can accumulate, collide, scatter, and accrete. Intermediate mass black hole formation is likely in these disk locations, which may lead to preferential gap and cavity creation at these radii. Our model thus has significant implications for SMBH growth as well as gravitational wave source populations

Modeling collisions in circumstellar debris disks

Science.gov (United States)

Nesvold, Erika

2015-10-01

Observations of resolved debris disks show a spectacular variety of features and asymmetries, including inner cavities and gaps, inclined secondary disks or warps, and eccentric, sharp-edged rings. Embedded exoplanets could create many of these features via gravitational perturbations, which sculpt the disk directly and by generating planetesimal collisions. In this thesis, I present the Superparticle Model/Algorithm for Collisions in Kuiper belts and debris disks (SMACK), a new method for simultaneously modeling, in 3-D, the collisional and dynamical evolution of planetesimals in a debris disk with planets. SMACK can simulate azimuthal asymmetries and how these asymmetries evolve over time. I show that SMACK is stable to numerical viscosity and numerical heating over 107 yr, and that it can reproduce analytic models of disk evolution. As an example of the algorithm's capabilities, I use SMACK to model the evolution of a debris ring containing a planet on an eccentric orbit and demonstrate that differential precession creates a spiral structure as the ring evolves, but collisions subsequently break up the spiral, leaving a narrower eccentric ring. To demonstrate SMACK's utility in studying debris disk physics, I apply SMACK to simulate a planet on a circular orbit near a ring of planetesimals that are experiencing destructive collisions. Previous simulations of a planet opening a gap in a collisionless debris disk have found that the width of the gap scales as the planet mass to the 2/7th power (alpha = 2/7). I find that gap sizes in a collisional disk still obey a power law scaling with planet mass, but that the index alpha of the power law depends on the age of the system t relative to the collisional timescale t coll of the disk by alpha = 0.32(t/ tcoll)-0.04, with inferred planet masses up to five times smaller than those predicted by the classical gap law. The increased gap sizes likely stem from the interaction between collisions and the mean motion

THREE-DIMENSIONAL DISK-PLANET TORQUES IN A LOCALLY ISOTHERMAL DISK

International Nuclear Information System (INIS)

D'Angelo, Gennaro; Lubow, Stephen H.

2010-01-01

We determine an expression for the Type I planet migration torque involving a locally isothermal disk, with moderate turbulent viscosity (5 x 10 -4 ∼< α ∼< 0.05), based on three-dimensional nonlinear hydrodynamical simulations. The radial gradients (in a dimensionless logarithmic form) of density and temperature are assumed to be constant near the planet. We find that the torque is roughly equally sensitive to the surface density and temperature radial gradients. Both gradients contribute to inward migration when they are negative. Our results indicate that two-dimensional calculations with a smoothed planet potential, used to account for the effects of the third dimension, do not accurately determine the effects of density and temperature gradients on the three-dimensional torque. The results suggest that substantially slowing or stopping planet migration by means of changes in disk opacity or shadowing is difficult and appears unlikely for a disk that is locally isothermal. The scalings of the torque and torque density with planet mass and gas sound speed follow the expectations of linear theory. We also determine an improved formula for the torque density distribution that can be used in one-dimensional long-term evolution studies of planets embedded in locally isothermal disks. This formula can be also applied in the presence of mildly varying radial gradients and of planets that open gaps. We illustrate its use in the case of migrating super-Earths and determine some conditions sufficient for survival.

Angular momentum transfer in steady disk accretion

International Nuclear Information System (INIS)

Gorbatskij, V.G.

1977-01-01

The conditions of steady disk accretion have been investigated. The disk axisymmetric model is considered. It is shown that the gas is let at the outer boundary of the disk with the azimuthal velocity which is slightly less than the Kepler circular one. Gas possesses the motion quality moment which is transferred from the outer layers of the disk to the surface of the star. The steady state of the disk preserved until the inflow of the moment to the star increases its rotation velocity up to magnitudes close to the critical one

Time-Dependent Variations of Accretion Disk

Directory of Open Access Journals (Sweden)

Hye-Weon Na

1987-06-01

Full Text Available In dward nova we assume the primary star as a white dwarf and the secondary as the late type star which filled Roche lobe. Mass flow from the secondary star leads to the formation of thin accretion disk around the white dwarf. We use the α parameter as viscosity to maintain the disk form and propose that the outburst in dwarf nova cause the steep increase of source term. With these assumptions we solve the basic equations of stellar structure using Newton-Raphson method. We show the physical parameters like temperature, density, pressure, opacity, surface density, height and flux to the radius of disk. Changing the value of α, we compare several parameters when mass flow rate is constant with those of when luminosity of disk is brightest. At the same time, we obtain time-dependent variations of luminosity and mass of disk. We propose the suitable range of α is 0.15-0.18 to the difference of luminosity. We compare several parameters of disk with those of the normal late type stars which have the same molecular weight of disk is lower. Maybe the outburst in dwarf nova is due to the variation of the α value instead of increment of mass flow from the secondary star.

[Management of disk displacement with condylar fracture].

Science.gov (United States)

Yu, Shi-bin; Li, Zu-bing; Yang, Xue-wen; Zhao, Ji-hong; Dong, Yao-jun

2003-07-01

To investigate clinical features of disk displacement during the course of condylar fracture and to explore the techniques of disk reposition and suturation. 32 patients (10 females and 22 males) who had disk displacements with condylar fractures were followed up. Reduction and reposition of the dislocated disks simultaneously with fixation of fractures were performed. 7 patients underwent intermaxillary fixation with elastic bands for 1 to 2 weeks. The occlusions were satisfactory in all cases but one for the reason of ramus height loss. No TMJ symptom was found when examined 3 months post operation. Anterior disk displacements were most occurred with high condylar process fractures. Surgical reposition and suturation of disk play an important role for the later TMJ-function.

Dust evolution in protoplanetary disks

OpenAIRE

Gonzalez , Jean-François; Fouchet , Laure; T. Maddison , Sarah; Laibe , Guillaume

2007-01-01

6 pages, 5 figures, to appear in the Proceedings of IAU Symp. 249: Exoplanets: Detection, Formation and Dynamics (Suzhou, China); International audience; We investigate the behaviour of dust in protoplanetary disks under the action of gas drag using our 3D, two-fluid (gas+dust) SPH code. We present the evolution of the dust spatial distribution in global simulations of planetless disks as well as of disks containing an already formed planet. The resulting dust structures vary strongly with pa...

Fallback disks & magnetars: prospects & possibilities

Science.gov (United States)

Alpar, M. A.

Some bound matter in the form of a fallback disk may be an initial parameter of isolated neutron stars at birth which along with the initial rotation rate and dipole and higher multipole magnetic moments determines the evolution of neutron stars and the categories into which they fall This talk reviews the strengths and difficulties of fallback disk models in explaining properties of isolated neutron stars of different categories Evidence for and observational limits on fallback disks will also be discussed

MIGRATION TRAPS IN DISKS AROUND SUPERMASSIVE BLACK HOLES

Energy Technology Data Exchange (ETDEWEB)

Bellovary, Jillian M.; Low, Mordecai-Mark Mac; McKernan, Barry; Ford, K. E. Saavik [Department of Astrophysics, American Museum of Natural History, Central Park West at 79th Street, NY 10024 (United States)

2016-03-10

Accretion disks around supermassive black holes (SMBHs) in active galactic nuclei (AGNs) contain stars, stellar mass black holes, and other stellar remnants, which perturb the disk gas gravitationally. The resulting density perturbations exert torques on the embedded masses causing them to migrate through the disk in a manner analogous to planets in protoplanetary disks. We determine the strength and direction of these torques using an empirical analytic description dependent on local disk gradients, applied to two different analytic, steady-state disk models of SMBH accretion disks. We find that there are radii in such disks where the gas torque changes sign, trapping migrating objects. Our analysis shows that major migration traps generally occur where the disk surface density gradient changes sign from positive to negative, around 20–300R{sub g}, where R{sub g} = 2GM/c{sup 2} is the Schwarzschild radius. At these traps, massive objects in the AGN disk can accumulate, collide, scatter, and accrete. Intermediate mass black hole formation is likely in these disk locations, which may lead to preferential gap and cavity creation at these radii. Our model thus has significant implications for SMBH growth as well as gravitational wave source populations.

Circumstellar disks around binary stars in Taurus

Energy Technology Data Exchange (ETDEWEB)

Akeson, R. L. [NASA Exoplanet Science Institute, IPAC/Caltech, Pasadena, CA 91125 (United States); Jensen, E. L. N. [Swarthmore College, Department of Physics and Astronomy, Swarthmore, PA 19081 (United States)

2014-03-20

We have conducted a survey of 17 wide (>100 AU) young binary systems in Taurus with the Atacama Large Millimeter Array (ALMA) at two wavelengths. The observations were designed to measure the masses of circumstellar disks in these systems as an aid to understanding the role of multiplicity in star and planet formation. The ALMA observations had sufficient resolution to localize emission within the binary system. Disk emission was detected around all primaries and 10 secondaries, with disk masses as low as 10{sup –4} M {sub ☉}. We compare the properties of our sample to the population of known disks in Taurus and find that the disks from this binary sample match the scaling between stellar mass and millimeter flux of F{sub mm}∝M{sub ∗}{sup 1.5--2.0} to within the scatter found in previous studies. We also compare the properties of the primaries to those of the secondaries and find that the secondary/primary stellar and disk mass ratios are not correlated; in three systems, the circumsecondary disk is more massive than the circumprimary disk, counter to some theoretical predictions.

Evaluation of powder metallurgy superalloy disk materials

Science.gov (United States)

Evans, D. J.

1975-01-01

A program was conducted to develop nickel-base superalloy disk material using prealloyed powder metallurgy techniques. The program included fabrication of test specimens and subscale turbine disks from four different prealloyed powders (NASA-TRW-VIA, AF2-1DA, Mar-M-432 and MERL 80). Based on evaluation of these specimens and disks, two alloys (AF2-1DA and Mar-M-432) were selected for scale-up evaluation. Using fabricating experience gained in the subscale turbine disk effort, test specimens and full scale turbine disks were formed from the selected alloys. These specimens and disks were then subjected to a rigorous test program to evaluate their physical properties and determine their suitability for use in advanced performance turbine engines. A major objective of the program was to develop processes which would yield alloy properties that would be repeatable in producing jet engine disks from the same powder metallurgy alloys. The feasibility of manufacturing full scale gas turbine engine disks by thermomechanical processing of pre-alloyed metal powders was demonstrated. AF2-1DA was shown to possess tensile and creep-rupture properties in excess of those of Astroloy, one of the highest temperature capability disk alloys now in production. It was determined that metallographic evaluation after post-HIP elevated temperature exposure should be used to verify the effectiveness of consolidation of hot isostatically pressed billets.

Photoacoustic FTIR spectroscopic study of undisturbed nacre from red abalone

Science.gov (United States)

Verma, Devendra; Katti, Kalpana; Katti, Dinesh

2006-07-01

In this work, photoacoustic Fourier transform infrared (PA-FTIR) spectroscopy has been utilized to study interfacial interactions of undisturbed nacre and nacre powder from red abalone shell. The spectra of both undisturbed nacre and nacre powder showed characteristic bands of aragonite and proteins. Although nacre powder and undisturbed nacre are chemically identical, PA-FTIR spectrum of undisturbed nacre is found to be significantly different from that of nacre powder. A broad and strong band is observed at around 1485 cm -1 in nacre powder. The intensity of this band is notably reduced in undisturbed nacre. This result is explained on the basis of interfacial interactions between aragonite platelets and acidic proteins. It is also observed that band at around 1788 cm -1 originates from three overlapping bands 1797, 1787 and 1778 cm -1. The band at around 1787 cm -1 is assigned to C dbnd O stretching of carboxylate groups of acidic proteins. The other two bands at 1797 and 1778 cm -1, originate from aragonite and have been assigned to combination bands, ν 3 + ν 4a and ν 3 + ν 4b, respectively. For the study of stratification in undisturbed nacre, PA-FTIR spectra have been collected in step scan mode. The variation in spectra with depth can be attributed to changes in conformation of proteins as well as interfacial interactions.

THE DISK IMAGING SURVEY OF CHEMISTRY WITH SMA. I. TAURUS PROTOPLANETARY DISK DATA

International Nuclear Information System (INIS)

Oeberg, Karin I.; Qi Chunhua; Andrews, Sean M.; Espaillat, Catherine; Van Kempen, Tim A.; Wilner, David J.; Fogel, Jeffrey K. J.; Bergin, Edwin A.; Pascucci, Ilaria

2010-01-01

Chemistry plays an important role in the structure and evolution of protoplanetary disks, with implications for the composition of comets and planets. This is the first of a series of papers based on data from DISCS, a Submillimeter Array survey of the chemical composition of protoplanetary disks. The six Taurus sources in the program (DM Tau, AA Tau, LkCa 15, GM Aur, CQ Tau, and MWC 480) range in stellar spectral type from M1 to A4 and offer an opportunity to test the effects of stellar luminosity on the disk chemistry. The disks were observed in 10 different lines at ∼3'' resolution and an rms of ∼100 mJy beam -1 at ∼0.5 km s -1 . The four brightest lines are CO 2-1, HCO + 3-2, CN 2 33/4/2 - 1 22/3/1 , and HCN 3-2, and these are detected toward all sources (except for HCN toward CQ Tau). The weaker lines of CN 2 22 -1 11 , DCO + 3-2, N 2 H + 3-2, H 2 CO 3 03 -2 02 , and 4 14 -3 13 are detected toward two to three disks each, and DCN 3-2 only toward LkCa 15. CH 3 OH 4 21 -3 1 2 and c-C 3 H 2 are not detected. There is no obvious difference between the T Tauri and Herbig Ae sources with regard to CN and HCN intensities. In contrast, DCO + , DCN, N 2 H + , and H 2 CO are detected only toward the T Tauri stars, suggesting that the disks around Herbig Ae stars lack cold regions for long enough timescales to allow for efficient deuterium chemistry, CO freeze-out, and grain chemistry.

Simultaneous measurements of disk vibration and pressure fluctuation in turbulent flow developing in a model hard disk drive

Energy Technology Data Exchange (ETDEWEB)

Kurashima, D.; Naka, Y.; Fukagata, K. [Department of Mechanical Engineering, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522 (Japan); Obi, S., E-mail: obsn@mech.keio.ac.jp [Department of Mechanical Engineering, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522 (Japan)

2011-06-15

The complex flow features inside hard disk drive models are investigated in an axisymmetric and a semi-open shroud configurations. For the axisymmetric case, we have employed both experimental and computational approaches. The experiment focuses on both flow dynamics and the disk vibration, where measurements of the fluctuating pressure and velocity are undertaken at some representative points. The correlation between the disk vibration and the fluctuating pressure in the turbulent flow between disks is evident from the spectral analysis. The experimentally observed fluctuating pressure and velocity are partly due to the disk vibration and its contribution could be estimated by comparing the experiment with the results of a large eddy simulation. For the semi-open shroud case, although the characteristic peaks attributable to the large-scale vortical structure are still observed in the power spectra, the pressure fluctuation and the disk vibration are suppressed when the arm is inserted.

MOLECULAR DISK PROPERTIES IN EARLY-TYPE GALAXIES

International Nuclear Information System (INIS)

Xu, X.; Walker, C.; Narayanan, D.

2010-01-01

We study the simulated CO emission from elliptical galaxies formed in the mergers of gas-rich disk galaxies. The cold gas not consumed in the merger-driven starburst quickly resettles into a disk-like configuration. By analyzing a variety of arbitrary merger orbits that produce a range of fast- to slow-rotating remnants, we find that molecular disk formation is a fairly common consequence of gas-rich galaxy mergers. Hence, if a molecular disk is observed in an early-type merger remnant, it is likely the result of a 'wet merger' rather than a 'dry merger'. We compare the physical properties from our simulated disks (e.g., size and mass) and find reasonably good agreement with recent observations. Finally, we discuss the detectability of these disks as an aid to future observations.

Rotation of gas above the galactic disk

International Nuclear Information System (INIS)

Gvaramadze, V.V.; Lominadze, D.G.

1988-01-01

The galactic disk is modeled by an oblate spheroid with confocal spherodial isodensity surfaces. An explicit analytic expression is found for the angular velocity of the gas outside the disk. The parameters of a three-component model of a spiral galaxy (oblate spheroid with central hole, bulge, and massive corona) are chosen in such a way as to obtain in the disk a two-hump rotation curve (as in the Galaxy, M 31, and M 81). It is shown that at heights absolute value z ≤ 2 kpc the gas rotates in the same manner as the disk. However, at greater heights the rotation curve ceases to have two humps. Allowance for the pressure gradient of the gas slightly changes the rotation curve directly above the disk (r r/sub disk/)

Studies of Young, Star-forming Circumstellar Disks

Science.gov (United States)

Bae, Jaehan

2017-08-01

Disks of gas and dust around forming stars - circumstellar disks - last only a few million years. This is a very small fraction of the entire lifetime of Sun-like stars, several billion years. Nevertheless, by the time circumstellar disks dissipate stars complete building up their masses, giant planets finish accreting gas, and terrestrial bodies are nearly fully grown and ready for their final assembly to become planets. Understanding the evolution of circumstellar disks are thus crucial in many contexts. Using numerical simulations as the primary tool, my thesis has focused on the studies of various physical processes that can occur throughout the lifetime of circumstellar disks, from their formation to dispersal. Chapters 2, 3, and 4 emphasize the importance of early evolution, during which time a forming star-disk system obtains mass from its natal cloud: the infall phase. In Chapter 2 and 3, I have modeled episodic outbursts of accretion in protostellar systems resulting from disk instabilities - gravitational instability and magnetorotational instability. I showed that outbursts occur preferentially during the infall phase, because the mass addition provides more favorable conditions for gravitational instability to initiate the outburst cycle, and that forming stars build up a significant fraction of their masses through repeated short-lived, episodic outbursts. The infall phase can also be important for the formation of planets. Recent ALMA observations revealed sets of bright and dark rings in circumstellar disks of young, forming stars, potentially indicating early formation of planets. In Chapter 4, I showed that infall streams can create radial pressure bumps near the outer edge of the mass landing on the disk, from which vortices can form, collecting solid particles very efficiently to make initial seeds of planets. The next three chapters highlight the role of planets in setting the observational appearance and the evolution of circumstellar disks

Dynamics of acoustically levitated disk samples.

Science.gov (United States)

Xie, W J; Wei, B

2004-10-01

The acoustic levitation force on disk samples and the dynamics of large water drops in a planar standing wave are studied by solving the acoustic scattering problem through incorporating the boundary element method. The dependence of levitation force amplitude on the equivalent radius R of disks deviates seriously from the R3 law predicted by King's theory, and a larger force can be obtained for thin disks. When the disk aspect ratio gamma is larger than a critical value gamma(*) ( approximately 1.9 ) and the disk radius a is smaller than the critical value a(*) (gamma) , the levitation force per unit volume of the sample will increase with the enlargement of the disk. The acoustic levitation force on thin-disk samples ( gammaacoustic field for stable levitation of a large water drop is to adjust the reflector-emitter interval H slightly above the resonant interval H(n) . The simulation shows that the drop is flattened and the central parts of its top and bottom surface become concave with the increase of sound pressure level, which agrees with the experimental observation. The main frequencies of the shape oscillation under different sound pressures are slightly larger than the Rayleigh frequency because of the large shape deformation. The simulated translational frequencies of the vertical vibration under normal gravity condition agree with the theoretical analysis.

Comparison of Rosco Neo-Sensitabs with Oxoid paper disks in EUCAST disk diffusion antimicrobial susceptibility testing on Mueller-Hinton agar

DEFF Research Database (Denmark)

Justesen, U S; Acar, Ziyap; Olsson, K

2013-01-01

This study compared Neo-Sensitabs with Oxoid paper disks using the European Committee on Antimicrobial Susceptibility Testing (EUCAST) disk diffusion antimicrobial susceptibility test on Mueller-Hinton agar. The EUCAST-recommended quality control strains (Escherichia coli ATCC 25922, Pseudomonas...... paper disks for EUCAST disk diffusion antimicrobial susceptibility testing on Mueller-Hinton agar....

Working with arrays of inexpensive EIDE disk drives

International Nuclear Information System (INIS)

Sanders, D.; Riley, C.; Cremaldi, L.; Summers, D.; Petravick, D.

2000-01-01

In today's marketplace, the cost per Terabyte of disks with EIDE interfaces is about a third that of disks with SCSI. Hence, three times as many particle physics events could be put online with EIDE. The modern EIDE interface includes many of the performance features that appeared earlier in SCSI. EIDE bus speeds approach 33 Megabytes/s and need only be shared between two disks rather than seven disks. The interal I/O rate of very fast (and expensive) SCSI disks is only 50% greater than EIDE disks. Hence, two EIDE disks whose combined cost is much less than one very fast SCSI disk can actually give more data throughput due to the advantage of multiple spindles and head actuators. The authors explore the use of 12 and 16 Gigabyte EIDE disks with motherboard and PCI bus card interfaces on a number of operating systems and CPUs. These include Red Hat Linux and Windows 95/98 on a Pentium, MacOS and Apple's Rhapsody/NeXT/UNIX on a PowerPC, and Sun Solaris on a UltraSparc 10 workstation

Ultrafast disk lasers and amplifiers

Science.gov (United States)

Sutter, Dirk H.; Kleinbauer, Jochen; Bauer, Dominik; Wolf, Martin; Tan, Chuong; Gebs, Raphael; Budnicki, Aleksander; Wagenblast, Philipp; Weiler, Sascha

2012-03-01

Disk lasers with multi-kW continuous wave (CW) output power are widely used in manufacturing, primarily for cutting and welding applications, notably in the automotive industry. The ytterbium disk technology combines high power (average and/or peak power), excellent beam quality, high efficiency, and high reliability with low investment and operating costs. Fundamental mode picosecond disk lasers are well established in micro machining at high throughput and perfect precision. Following the world's first market introduction of industrial grade 50 W picosecond lasers (TruMicro 5050) at the Photonics West 2008, the second generation of the TruMicro series 5000 now provides twice the average power (100 W at 1030 nm, or 60 W frequency doubled, green output) at a significantly reduced footprint. Mode-locked disk oscillators achieve by far the highest average power of any unamplified lasers, significantly exceeding the 100 W level in laboratory set-ups. With robust long resonators their multi-microjoule pulse energies begin to compete with typical ultrafast amplifiers. In addition, significant interest in disk technology has recently come from the extreme light laser community, aiming for ultra-high peak powers of petawatts and beyond.

Equilibrium figures for beta Lyrae type disks

International Nuclear Information System (INIS)

Wilson, R.E.

1981-01-01

Accumulated evidence for a geometrically and optically thick disk in the β Lyrae system has now established the disk's basic external configuration. Since the disk has been constant in its main properties over the historical interval of β Lyrae observations and also seems to have a basically well-defined photosphere, it is now time to being consideration of its sturcture. Here, we compute equilibrium figures for self-gravitating disks around stars in binary systems as a start toward eventual computation of complete disk models. A key role is played by centrifugally limited rotation of the central star, which would naturally arise late in the rapid phase of mass transfer. Beta Lyrae is thus postulated to be a double-contact binary, which makes possible nonarbitrary separation of star and disk into separate structures. The computed equilibrium figures are three-dimensional, as the gravitation of the second star is included. Under the approximation that the gravitational potential of the disk is that of a thin wire and that the local disk angular velocity is proportional to u/sup n/ (u = distance from rotation axis), we comptue the total potential and locate equipotential surfaces. The centrifugal potential is written in a particularly convenient form which permits one to change the rotation law discontinuously (for example, at the star-disk coupling point) while ensuring that centrifugal potential and centrifigual force are continuous functions of position. With such a one-parameter rotation law, one can find equilibrium disk figures with dimensions very similar to those found in β Lyrae, but considerations of internal consistency demand at least a two-parameter law

Recent development of disk lasers at TRUMPF

Science.gov (United States)

Schad, Sven-Silvius; Gottwald, Tina; Kuhn, Vincent; Ackermann, Matthias; Bauer, Dominik; Scharun, Michael; Killi, Alexander

2016-03-01

The disk laser is one of the most important laser concepts for today's industrial laser market. Offering high brilliance at low cost, high optical efficiency and great application flexibility the disk laser paved the way for many industrial laser applications. Over the past years power and brightness increased and the disk laser turned out to be a very versatile laser source, not only for welding but also for cutting. Both, the quality and speed of cutting are superior to CO2-based lasers for a vast majority of metals, and, most important, in a broad thickness range. In addition, due to the insensitivity against back reflections the disk laser is well suited for cutting highly reflective metal such as brass or copper. These advantages facilitate versatile cutting machines and explain the high and growing demand for disk lasers for applications besides welding applications that can be observed today. From a today's perspective the disk principle has not reached any fundamental limits regarding output power per disk or beam quality, and offers numerous advantages over other high power resonator concepts, especially over fiber lasers or direct diode lasers. This paper will give insight in the latest progress in kilowatt class cw disk laser technology at TRUMPF and will discuss recent power scaling results as well.

Radiative Transfer Modeling in Proto-planetary Disks

Science.gov (United States)

Kasper, David; Jang-Condell, Hannah; Kloster, Dylan

2016-01-01

Young Stellar Objects (YSOs) are rich astronomical research environments. Planets form in circumstellar disks of gas and dust around YSOs. With ever increasing capabilities of the observational instruments designed to look at these proto-planetary disks, most notably GPI, SPHERE, and ALMA, more accurate interfaces must be made to connect modeling of the disks with observation. PaRTY (Parallel Radiative Transfer in YSOs) is a code developed previously to model the observable density and temperature structure of such a disk by self-consistently calculating the structure of the disk based on radiative transfer physics. We present upgrades we are implementing to the PaRTY code to improve its accuracy and flexibility. These upgrades include: creating a two-sided disk model, implementing a spherical coordinate system, and implementing wavelength-dependent opacities. These upgrades will address problems in the PaRTY code of infinite optical thickness, calculation under/over-resolution, and wavelength-independent photon penetration depths, respectively. The upgraded code will be used to better model disk perturbations resulting from planet formation.

Herniated lumbar intervertebral disk

International Nuclear Information System (INIS)

Hochhauser, L.; Cacayorin, E.D.; Karcnik, T.J.; McGowan, D.P.; Clark, K.G.; Storrs, D.; Kieffer, S.A.

1988-01-01

From a series of 25 patients with low-back pain and sciatica who subsequently underwent surgical exploration, 24 lumbar herniated disks and one asymmetrically bulging disk were correctly diagnosed with use of a 0.5-T MR imaging unit. The radiologic findings on saggital images included a polypoid protrusion beyond the posterior margin of the vertebral bodies more clearly displayed with T1-weighted than with T-2 weighted sequences and a focal extension into the extradural space on axial views. In most, the signal intensity of HNP was isointense to the disk of origin. The study suggests that MR imaging is currently capable of accurately predicting an HNP. The diagnosis is based primarily on morphologic characteristics rather than signal intensity alterations

A 100 au Wide Bipolar Rotating Shell Emanating from the HH 212 Protostellar Disk: A Disk Wind?

Science.gov (United States)

Lee, Chin-Fei; Li, Zhi-Yun; Codella, Claudio; Ho, Paul T. P.; Podio, Linda; Hirano, Naomi; Shang, Hsien; Turner, Neal J.; Zhang, Qizhou

2018-03-01

HH 212 is a Class 0 protostellar system found to host a “hamburger”-shaped dusty disk with a rotating disk atmosphere and a collimated SiO jet at a distance of ∼400 pc. Recently, a compact rotating outflow has been detected in SO and SO2 toward the center along the jet axis at ∼52 au (0.″13) resolution. Here we resolve the compact outflow into a small-scale wide-opening rotating outflow shell and a collimated jet, with the observations in the same S-bearing molecules at ∼16 au (0.″04) resolution. The collimated jet is aligned with the SiO jet, tracing the shock interactions in the jet. The wide-opening outflow shell is seen extending out from the inner disk around the SiO jet and has a width of ∼100 au. It is not only expanding away from the center, but also rotating around the jet axis. The specific angular momentum of the outflow shell is ∼40 au km s‑1. Simple modeling of the observed kinematics suggests that the rotating outflow shell can trace either a disk wind or disk material pushed away by an unseen wind from the inner disk or protostar. We also resolve the disk atmosphere in the same S-bearing molecules, confirming the Keplerian rotation there.