• Journal of Fisheries and Marine Sciences Education
• /
• v.25 no.2
• /
• pp.341-348
• /
• 2013

The auditory thresholds for 7 specimens of the sharp toothed eel Muraensox cinerus were measured at 5 frequencies by heartbeat conditioning method using pure tones coupled with a delayed electric shock. The audible range of the sharp toothed eel extended from 80Hz to 300Hz with the best sensitivity around 80Hz and 100Hz. In addition, the auditory thresholds over 200Hz increased rapidly. The mean auditory thresholds of the sharp toothed eel at the test frequencies of 80Hz, 100Hz, 200Hz and 300Hz were 87dB, 86dB, 105dB and 126dB, respectively. Auditory masking was determined for the sharp toothed eel by using masking stimuli with the spectrum level range of about 70~80dB (0dB re $1{\mu}Pa/\sqrt{Hz}$). According to white noise level, the auditory thresholds increased as compared with thresholds in a quiet background noise. The noise spectrum level at the start of masking was distributed at the range of about 64dB within 80~100Hz. Critical ratio ranged from minimum 24dB to maximum 40dB at test frequencies of 80Hz~200Hz.

• Journal of Environmental Science International
• /
• v.20 no.4
• /
• pp.551-554
• /
• 2011

The production of the sharp-toothed eel by commercial catch off waters of Korea is annually declined after 1978. This study was carried out to obtain the stock management of the sharp-toothed eel using the PCR-aided RFLP method. The mtDNA COI gene was amplified using species-specific primers and PCR product was observed to 700 bp. Amplified DNA fragments were treated with six kinds of restriction enzymes (BaeHI, EcoRI, PstI, Ksp22, HinfI and HaeIII). The treatment of HaeIII showed a distinct PCR product between Yeosu/Jinhae/Jeju/Goseoung and Jangheung/Haenam populations that were observed from 300 to 400 bp in reference to 100 bp molecular marker. However, DNA fragment within populations had an identical pattern. The phylogenetic homology is 82% between two populations inferred from RFLP PCR product pattern using NTsysPC ver. 2.1. The use of HaeIII plays an important role in discriminating populations. It is thought that adults after over-wintering in the southern part of Jeju migrate to the Yeosu, Jinhae and Goseoung regions to spawn instead of to southwestern waters. Individuals within populations showed a relatively active genetic mixing and migration regardless of geography. However, the genetic ancestor of Jangheung and Haenam populations is appeared to be more adjacent to China or Japan than Jeju.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.48 no.3
• /
• pp.217-226
• /
• 2012

Reproductive ecology of the sharp toothed eel, Muraenesox cinereus was investigated based on the samples captured in southern Korean waters from January 2010 to December 2011. Gonadosomatic index began to increase in April, and reached maximum between July to August. After spawning it began to decrease from October. Reproductive season was estimated to April-September, with peak in July. Fecundity was proportional to the size of the female, with the clutch size varying from 56,000 eggs in the smallest female (anal length, 27.0cm) to 1,400,000 eggs in the largest (anal length, 49.5cm). Size at 50% sexual maturity ($AL_{50}$), determined from mature females, were 21.9cm. Annual reproductive cycles of this species could be divided into four successive stages; immature stage (October-February), maturing stage (March-May), mature stage (June-August) and spent stage (August-October).

• KSBB Journal
• /
• v.25 no.4
• /
• pp.387-394
• /
• 2010

This study was conducted to investigate effect of complex extract of various mushrooms and sharp toothed eel on the skin conditions with atopic dermatitis and acne symptoms. The total phenol concentration was increased in order of hot water> ethanol> ethyl acetate> petroleum ether> chloroform extract. Especially, when the hot water extract was used, it was about 2-3 fold higher than that of ethyl acetate, petroleumether, and chloroform extract. When the complex extract concentration was increased from 1.0 to 50 mg/L, the DPPH scavenging rate increased from 10.1 to 81.4%. The reduction power was sharply increased from 0.05 to 0.27 (700 nm) when the complex extract concentration was increased from 25 to 75 mg/L. However, above 100 mg/L, it was not decreased. In the case of SOD-like activity, it was 45.7% at 100 mg/L. Total numbers of patients with atopic dermatitis were 15 and 5 patients with severe acne symptoms. According to photos taken before and after the treatment and questionnaire results, considerable improvements in skin conditions are observed in the patients with atopic dermatitis and acne. For atopic patients, erythema and edema have been improved but the degree of effect was dependent on the individual's constitution. Concerning acne, the effect of coating of the extracts was prominent for first week and the degree decreased with time till 4 weeks. The complex extracts wereefficient in soothing rash and maturation. Side effects such as a scar were not detected during the application and treatment.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.35 no.1
• /
• pp.97-104
• /
• 2002

Protein hydrolysate was prepared as a natural flavor stock from the sharp toothed eel (Muraenesox cinereus) mince using com-mercially available proteolytic enzymes, Alcalase, Neutrase, Protamex, and Flavourzyme. A 6 hr hydrolysis of mince, to which water of the equal weight of the mince was added, with $2\%$ (w/w, protein weight) Elavourzyme at $50^{\circ}$ yielded a hydrolysate of the highest acceptability. Removing the access lipid in liquified hydrolysate (not dehydrated) after enzyme hydrolysis, five times repetitive extraction using n-hexane (liquified hydrolysate : n-hexane=4 : 1, v/v) was effective, resulting in less than $1\%$ lipid content of the dehydrated-hydrolysate. The amino acid composition of the hydrolysate (prepared with Flavourzyme) was similar to that of the starting material. Hydrolysis led to an increase in concentration of not only total free amino acid but also free amino acid such as serine, glutamic acid, alanine, and methionine responsible for umami taste, especially up to about 40 times for methionine. Major free amino acids in amount were leucine, phenylalanine, valine, alanine, and isoleucine and they comprised about half of the total free amino acids, Moisture adsorption, fat adsorption, emulsifying capacity, and foaming capacity of the hydrolysate were 870.1 $\pm$ $7.9\%$, 352.0$\pm$ $5.3\%$, 50.3 $\pm$ $1.2\%$, and $87.5\pm$ $2.5\%$, respectively, and solubility was 83$\~$$84\%$ at acid pH range of 2$\~$4.

• Journal of Life Science
• /
• v.12 no.3
• /
• pp.233-241
• /
• 2002

Seasonal variation of uraenesox cinereus) muscle was investigated. Crude lipid content varied from 3.85 to 12.59 g/100g, comprising the highest content in November. The major fatty acids of total lipid, neutral lipid, and phospholipid were C16:0, C23:0, C16:1, C18:1, C20:5, and C22:6, but in phospholipid, Cl8:3n-6 was also the major fatty acid. The C22:6 content of the neutral lipid was much lower compared to that of the total lipid and phospholipid. The content of polyunsaturated fatty acids (ranged from 73.93 to 66.23%) in phospholipid was higher than that of any other lipid fraction. In glycolipid, C20:1 and C14:1 were higher compared to those of any other lipid fraction, but C20:5 and C22:6 were lower. The annual average ratio of n-3 to n-6 of total lipid, neutral lipid, phospholipid, and glycolipid was 10.82, 12.27, 6.63, and 6.50, respectively. The particular trend of seasonal variation of fatty acid composition was not showed in total and neutral lipid. However, the samples caught in September and November had a high crude lipid content with a significantly lower content of polyunsaturated fatty acids in phospholipid. Also, the content of monounsaturated fatty acids in glycolipid was lower in samples of September, November, and January.

• KSBB Journal
• /
• v.26 no.3
• /
• pp.260-265
• /
• 2011

This study aimed to examine the treatment effect of Muraenesox cinereus extract product combined with high frequency on men's damaged skin. The subjects were treated by a product containing M. cinereus extract combined with high frequency therapy for six weeks and tested in skin condition. First, for moisture level change, there was no significant difference between the control group treated only by high frequency therapy and the experimental group treated by a M. cinereus extract product combined with high frequency therapy. But the subjects who increased consistently in moisture level in the cheek and chin were more common in the experimental group. Second, for an oil level, prominently high increase was found in both the control group and the experimental group. Finally, for a rough level, while there was little difference in the control group between immediately after peeling and after six weeks, high improvement effect on a curve was found in the experimental group. Based on this result, cosmetics using M. cinereus extract may have a positive effect on men's skin which is exposed to several stress factors. Accordingly, this result will contribute to developing men's functional cosmetics.