• Korean Journal of Fisheries and Aquatic Sciences
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• v.39 no.3
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• pp.283-291
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• 2006

This study examined the development of a low-salt fermented seafood product using an ascidian (Halocynthia roretzi), and the optimum processing conditions and quality characteristics of the low-salt fermented ascidian (LSA). The optimum processing conditions for the LSA were as follows. The ascidian was shelled and its muscle sliced into 5 mm widths. This was soaked in a 10% salt and 1% sodium erythorbate solution for 20 min. The solution was drained and then the muscle was soaked in 0.1% sodium bisulfite solution for 1 min. To this was added a 1:1 mixture of anchovy sauce and rice gruel, and it was fermented at $5^{\circ}C$ for 15 days. The moisture content and salinity of the LSA were 75.0-75.4% and 8.0-8.5%, respectively. During salt-fermentation at $5^{\circ}C$ for 20 days, the amino-N content of the LSA increased, and the texture softened gradually. The viable cell counts in early salt-fermentation were $4.2-4.5{\times}10^4CFU/g$, and this decreased gradually. The ratio of saturated fatty acids tended to increase in early salt-fermentation, while that of polyunsaturated fatty acids decreased slightly. Chemical experiments and sensory evaluation showed that the dipping treatment in 1% sodium erythorbate solution and 0.1% sodium bisulfite solution resulted in a good color and prevented browning of the salt-fermented ascidian meat. Moreover, adding anchovy sauce and rice gruel mixture improved the flavor of the LSA.

• Journal of the Korean Society of Food Science and Nutrition
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• v.27 no.4
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• pp.603-608
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• 1998

Lipid oxidation in ascidian was studied when fresh, deshelled and sliced meats were fermented for 50 days at 5$\pm$2$^{\circ}C$ with 8%(w/w) salt and 0.1% papain. Antioxidative effects of butylated hydroxytoluene(BHT) and carotenoid extracts from ascidian tunic on lipid oxidation and oxidationrelated discoloration of ascidian meat during fermentation were investigated. Changes in peroxide value, carbonyl value, thiobarbituric acid value, fatty acids composition, the loss of total carotenoid and sensory evaluation were determined to assess the rancidity. Peroxide and carbonyl values in BHT and carotenoid extract treatments increased less than those of the control during fermentation. TBA value increased until 30 days, hereafter tended to decrease a little in the control during fermentation. TBA value increased until 30 days, hereafter tended to decrease a little in the control but it increased slowly until 40 days in cases of 0.02% BHT or 0.02% BHT with 0.05% carotenoid added. Fatty acids of fresh ascidian composed of polyenoic acid, saturated acid and monoenoic acid of 51.5%, 28.1% and 20.7%, respectively. Saturated fatty acids(C16:0, C14:0, C18:0) and monoenoic acids(C18:1, C16:1) increased while polyenoic acids(C20:5, C22:6) decreased during fermentation. Carotenoid was markedly degraded and discolored in the control during fermentation. But 0.02% BHT and 0.05% carotenoid treatments had bright color like fresh meat during 40 days. The results of sensory evaluation during the fermentation also convinced the retard of discoloration by the addition of BHT and carotenoid.

• Journal of Animal Science and Technology
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• v.44 no.1
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• pp.45-54
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• 2002

This study was conducted to evaluate the feeding value of ascidian tunic shell the effects of its dietary supplementation on laying performance, egg-yolk pigmentation, egg-shell strength and egg taurine content. A total of 168 brown layers at the age of 29wks in commercial cage were fed for 4 wks with 7 different diets containing ascidian tunic shel1(AST) at varying levels of 0$\sim$5% Dm or 0% AST with 100ppm carophyll red. No differences were found in egg production and weight among the treatments indicating that ascidian tunic shell did not adversely affect the laying performances. Adding the ascidian tunic shell to the diets increased egg-yolk pigmentation compared to the control and resulted in simillar or better effect on egg-yolk pigmentation compared to 100ppm carophyll red. The data suggest that ascidian tunic shell may be used as feed ingredients in layer diet enrichment of egg-yolk pigmentation in the place of carophyll red(chemical pigment). Specific gravity and breaking strength of egg shell were significantly increased by the adding ascidian tunic shell to the diet, suggesting that ascidian tunic shell may be used as feed ingredients for increasing egg shell strength. Also taurine content of egg was significantly increased with increasing supplementation of ascidian tunic shell to the diet(p<0.05). Therefore, ascidian tunic shell may be used as feed ingredients in laying hen diet to improve egg quality such as egg-yolk pigmentation, egg-shell strength and egg taurine enrichment.

• Bulletin of the Korean Chemical Society
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• v.23 no.1
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• pp.163-166
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• 2002

• Korean Journal of Fisheries and Aquatic Sciences
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• v.27 no.3
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• pp.240-246
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• 1994

This study was designed to determine the optimum pigment concentration supplemented in diet and feeding periods on the pigmentation of rainbow trout(Oncorhynchus mykiss) by using acetone-extracts of ascidian tunic as a natural pigment source. The eight pigmented diets contained carotenoid of ascidian tunic extracts at concentrations of 0, 200, 400, 800, 1,600 and 3,200mg/kg of diet, carophyll pink at concentration of 800mg/kg and commercial diet. No difference in pigment concentration was found between the ascidian extracts group and the control group until 4 weeks, but the redness of muscle and integument in the 1,600, 3,200mg/kg diet and carophyll pink was increased in the dorsal and caudal areas of fish from 6 weeks of age. In the sensory panel test, fish fed the ascidian tunic extracts diet were similar to those fed the carophyll pink diet. The optimum concentration and feeding periods for pigmentation of rainbow trout was found to be ascidian tunic extracts of 1,600mg/kg diet for 8 weeks.

• Development and Reproduction
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• v.15 no.1
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• pp.1-7
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• 2011

It is suggested that FGF/Ras/MEK/Erk signaling plays crucial roles in specification and cell division of the mesodermal precursor cells in ascidian embryos. To investigate how the number of cell division in tissue precursor cells is determined, we have characterized Wee1 homolog, Hr-Wee1 of the ascidian Halocynthia roretzi. We found that the Hr-Wee1 mRNA is expressed both maternally and zygotically. Maternal transcript is localized to the cytoplasm in the animal cells, while zygotic expression is seen in cells of the endoderm lineage from 32-cell to 110-cell stages. Zygotic in situ signal is detected in the A-line neural plate cells of neurulae, and in epidermal cells of the head region of tailbud embryos. Embryos treated with MEK signaling inhibitor showed a similar pattern to normal embryos in expression of Hr-Wee1. Therefore, it is likely that MEK signaling does not affect the maternal and zygotic expression of Hr-Wee1.

• Fisheries and Aquatic Sciences
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• v.12 no.1
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• pp.44-48
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• 2009

Nucleotide sequences of about 500 bp from the 5' end of mitochondrial (mt) DNA Cytochrome Oxidase I (COI) were analyzed to estimate the genetic variation between wild and cultured populations of the ascidian Halocynthia roretzi from two sites along the coast of Korea. A total of 25 haplotypes were defined by 21 variable nucleotide sites in the examined COI region. Genetic diversity (haplotype diversity and nucleotide divergence) of wild populations was higher than that of the cultured population. These data suggest that reduced genetic variation in the cultured population may have results from bottleneck effect caused by the use of a limited number of parental stock and pooling of gametes for fertilization. Pairwise population $F_{ST}$ estimates inferred that wild and cultured populations were genetically distinct. The combined results suggest that sequence polymorphism in the COI region would be preferable for estimating the genetic diversity of ascidian populations.

• KSBB Journal
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• v.28 no.1
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• pp.36-41
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• 2013

Carotenoids are fat-soluble red-orange colored pigments found in plants and seafood-derived products, including algae, seaweeds, and fish muscle. In this study, we have demonstrated the molecular mechanism underlying the antioxidants and anti-inflammatory properties of ascidian tunic carotenoids using mouse macrophage cell line (RAW 264.7). Cell viability was not affected by treatment of carotenoids < 10 ${\mu}g/mL$. This treatment also showed negative inhibition on lipopolysaccharide (LPS)-stimulated nitric oxide (NO) and cyclooxygenase-2 (COX-2). The DPPH radical scavenging activity of carotenoids was 47.2% at 100 mg/mL. It also has a potential reducing power (1.025) comparable with ascorbic acid (1.584). The ascidian tunic carotenoids would make a candidate for the commercially interesting biologically active cosmetic pigments.

• Development and Reproduction
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• v.25 no.4
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• pp.299-303
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• 2021

The ascidian Halocynthia aurantium (sea peach), a marine invertebrate, belongs to the same genus of the phylum Chordata along with the ascidian Halocynthia roretzi (sea pineapple), which is one of the model animals in the field of developmental biology. The characteristics of development and reproduction of H. aurantium are not yet known in detail. In order to find out the spawning period of H. aurantium, we investigated development of the gonads during the annual reproductive cycle. Testis and ovary were both in the bisexual gonads (ovotestes) of H. aurantium, which is a hermaphrodite like H. roretzi. In H. aurantium, the right gonad was longer and slightly larger than the left gonad throughout the year. In each gonad, the number of the testis gonoducts was slightly higher than that of the ovary gonoducts. These features were similarly observed in H. roretzi. However, the number of the testis gonoducts and the ovary gonoducts in each gonad of H. aurantium was about half that of H. roretzi. The gonads of H. aurantium contracted during the winter and summer seasons. The gonads decreased to the smallest size around February, and then started to increase again in March. The gonads were most developed in September of the year. Therefore, it is estimated that the spawning of H. aurantium begins around this period.

• Development and Reproduction
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• v.17 no.4
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• pp.389-397
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• 2013

FGF9/16/20 signaling pathway specify the developmental fates of notochord, mesenchyme, and neural cells in ascidian embryos. Although a conserved Ras/MEK/Erk/Ets pathway is known to be involved in this signaling, the detailed mechanisms of regulation of FGF signaling pathway have remained largely elusive. In this study, we have isolated Hr-Erf, an ascidian orthologue of vertebrate Erf, to elucidate interactions of transcription factors involved in FGF signaling of the ascidian embryo. The Hr-Erf cDNA encompassed 3110 nucleotides including sequence encoded a predicted polypeptide of 760 amino acids. The polypeptide had the Ets DNA-binding domain in its N-terminal region. In adult animals, Hr-Erf mRNA was predominantly detected in muscle, and at lower levels in ganglion, gills, gonad, hepatopancreas, and stomach by quantitative real-time PCR (QPCR) method. During embryogenesis, Hr-Erf mRNA was detected from eggs to early developmental stage embryos, whereas the transcript levels were decreased after neurula stage. Similar to the QPCR results, maternal transcripts of Hr-Erf was detected in the fertilized eggs by whole-mount in situ hybridization. Maternal mRNA of Hr-Erf was gradually lost from the neurula stage. Zygotic expression of Hr-Erf started in most blastomeres at the 8-cell stage. At gastrula stage, Hr-Erf was specifically expressed in the precursor cells of brain and mesenchyme. When MEK inhibitor was treated, embryos resulted in loss of Hr-Erf expression in mesenchyme cells, and in excess of Hr-Erf in a-line neural cells. These results suggest that zygotic Hr-Erf products are involved in specification of mesenchyme and neural cells.