The Nuclear DNA Content Determination of 31 Endemic Freshwater Fishes in Korea.

The main purpose of the current study was to obtain nuclear DNA content data among the representatives of the families and subfamilies of 31 endemic fishes that inhabit river of Korea. DNA contents of 31 endemic species were observed to rang from 1.5 to 4.8 pg DNA/nucleus. In Cyprinidae, DNA content of Abbottina springeri (1.5±0.03 pg DNA/nucleus) was the lowest value and DNA content of Carassius cuvieri (4.5±0.32 pg DNA/nucleus) was the highest value in all experimental groups. In Cobitidae, DNA content of Iksookimia longicorpa (3.9±0.17 pg DNA/nucleus) was the highest value and DNA content of Orthrias toni (1.5±0.18 pg DNA/nucleus) was the lowest value in all experimental groups. This study provides new information for a better understanding of the process of genomic evolution in 31 endemic species in river of Korea.

A review of studies on Oryzias dancena.

Oryzias dancena (Beloniformes; Teleostei), is a euryhaline teleost that mainly inhabits the brackish or freshwater of river mouths and estuaries around the Bay of Bengal and the Malay Peninsula. It also has a short interval between generations, with spawning possibilities just 60 days after hatching. The aim of this paper is to provide a review for the study of O. dancena based on the studies collected so far, and could form the basis for a wide category of researches including zootoxy, cytogenetics, anesthesia, tagging, salinity tolerance, reproduction, fish disease, chromosome engineering, and trnasgenesis in order to highlight the recent progress in different fields of study using this species.

Factors Predicting the Need for Early Surgical Intervention for Small Bowel Obstruction.

PURPOSE: Small bowel obstruction (SBO) is a common disease that requires hospitalization. The most common cause of SBO is postoperative adhesion. Delayed timing of operations in patients who need surgical intervention results in mortality or morbidity. A number of studies on SBO have established criteria for emergency surgery. However, few objective clinical parameters are available for screening patients who need a delayed operation. Therefore, we analyzed factors that affect the clinical course of SBO to select appropriate therapeutic plans for reducing the risk of complications in these patients. METHODS: We investigated the clinical characteristics of patients admitted to the surgery department of our hospital between January 1, 2015, and December 31, 2016, who were diagnosed with SBO. Patients were divided into an operative treatment group (n = 12) and a conservative treatment group (n = 96). We compared clinical characteristics between the 2 groups. RESULTS: The operative treatment group underwent more operations before SBO than the conservative treatment group (P = 0.007). Initial leukocyte counts (P = 0.004) and C-reactive protein (CRP) levels (P = 0.028) were elevated in the operative group. Body mass index (BMI) was lower in the operative group (P = 0.013). CONCLUSION: The number of operations before SBO, leukocyte counts, CRP levels, and BMI were useful parameters for selecting patients who needed an urgent operation for SBO.

The Sterilization Effect of Methylene Blue, Formalin, and Iodine on Egg and Adult Stage of Marine Medaka, Oryzias dancena.

The sterilization effects of methylene blue (MB), formalin, and iodine on the egg of marine medaka, Oryzias dancena, were investigated for disinfecting naididae worm, Chaetogaster diastrophus through sterilization. To determine harmfulness of MB, formalin, and iodine, lethal concentrations 50 (LC50) of three chemicals were analyzed in the eggs of marine medaka. The sterilized periods of each chemical were set at 1 hr. Sterilized rates of naididae worm in each chemical were significantly affected and increased drastically as the concentration of each chemical increased (p<0.05). Sterilization abilities of naididae worm were most effective for formalin, but survival rates of egg and hatched rates for formalin were lowest among each chemical. The LC50 of MB over 96 hrs were 185.26, 103.84, and 127.15 ppm for adults, juveniles, and eggs respectively. The toxic effects of MB were clearly dose dependent for each life stage (p<0.05). The toxicity sensitivity of juveniles to MB was dramatically higher than that of other groups. In 48 hrs after sterilization, cortisol and glucose concentrations of the adult group with MB treatment were significantly higher than those of the adult group with no treatment (p<0.05). This research provides useful data on sterilization effect of MB, formalin, and iodine, acute toxicity in marine medaka egg and toxicity, sensitivity of life stage of MB in marine medaka.

Changing Salinity Affects Hematological and Histological Response in Hybrids and Hybrid Triploids between River Puffer, Takifugu obscurus and Tiger Puffer, T. rubripes.

We investigated the physiological responses of the river puffer, Takifugu obscurus, the tiger puffer, T. rubripes, a hybrids of the two (river puffer×tiger puffer) and a hybrid triploids to acute changes of salinity from 30 psu to 0 psu and from 0 psu to 30 psu. The blood and plasma factors of each species were elevated for 48, 72, or 96 hrs, and thereafter decreased due to hyper-osmoregulation and hypo-osmoregulation. In hyper-osmoregulation and hypo-osmoregulation, the cortisol concentration of river puffer, hybrids, hybrid triploids and tiger puffer increased for 12 or 48 hrs, and decreased thereafter. Chloride cells in the gill filaments of each species increased with increasing salinity, and melano-macrophages in the kidney tissue of each species increased with decreasing salinity. In conclusion, the hematological and stress responses of the hybrids were between those of the river puffer and tiger puffer, and the hematological responses of the hybrid triploids were higher than those of the other groups. The stress response of the hybrids was more sensitive than that of the hybrid triploids. In all groups, the histological responses of kidney in hyper-osmoregulation were more sensitive than those in hypo-osmoregulation.

The Anesthetic Effects of Clove Oil and MS-222 on Far Eastern Catfish, Silurus asotus.

The objective of this study is to evaluate the anesthetic effects of clove oil and tricaine methanesulfonate (MS-222) on the Far Eastern catfish, Silurus asotus, by measuring the times to anesthesia and recovery. Each anesthetic effect of clove oil and MS-222 was tested in two groups of fish with different body sizes: a group of small fish (mean body length: 15.5±1.58 cm, mean body weight: 50.1±5.91 g, n=20) and a group of large fish (mean body length: 31.5±4.19 cm, mean body weight: 302.1±15.22 g, n=20). The anesthetics were used at concentrations of 200, 300, 400, 500, and 600 ppm. The results showed significant relationships between the concentration of the anesthetic and the body size of the fish. Each of these variables showed statistical significance (p<0.05). The time to anesthesia decreased linearly with increasing concentration in the large fish for both clove oil and MS-222 (p<0.05). Based on an optimal anesthetic time of approximately 1 min, the preferred concentrations of the anesthetics were 500 ppm for clove oil and 600 ppm for MS-222. Both the anesthetic time and the recovery time were shorter for the small fish than for the large fish (p<0.05). Our study showed that the smaller-sized Far Eastern catfish was more easily anesthetized and recovered more rapidly from anesthesia than the larger-sized fish.

Anaesthetic Efficacy and Physiological Response of Clove Oil and Lidocaine-HCl on River Puffer, Takifugu obscurus and Tiger Puffer, T. rubripes.

The effects of the anaesthetic agents, clove oil and mixture of clove oil with lidocaine-HCl were evaluated on river puffer, Takifugu obscurus and tiger puffer, T. rubripes. Anaesthesia times of clove oil were affected by water temperature (20℃, 24℃, and 28℃) and salinity (10, 20, and 30 ppt). Anaesthesia times of mixed samples were significantly similar with regard to exposure and recovery times, and all samples satisfied anaesthesia criteria (exposure time within 3 min and recovery time within 5 min) under the various temperatures and salinities, and the lowest to highest concentration of anaesthetics (p<0.05). Both species river puffer and tiger puffer had short exposure time with a high anaesthesia dose, high temperature (28℃) and intermediate salinity (20 ppt), and were highly affected by temperature and salinity (p<0.05). The mixed anaesthetics had rapid exposure times and long recovery times in contrast to the effects of clove oil. Cortisol concentrations under the conditions of various clove oil dosages, salinity, and temperature for both species increased until 12 hrs after recovery from anaesthesia (p<0.05). After 12 hrs, cortisol concentrations decreased until after 48 hrs (p<0.05). During the simulated transportation of both species, control and sedated clove oil groups (5 ppm) were measured for water parameters, dissolved oxygen (DO), CO2, respiratory frequency, NH4 +, and pH for 6 hrs in 1 hr intervals. Water parameters of sedated groups and controls were significantly different after 2 hrs (p<0.05).

Karyotypic Analysis of Chicken Grunt, Parapristipoma trilimeatum, Small Yellow Croaker, Larimichthys polyactis, and Brown Croaker, Miichthys miiuy.

To clarify the cytogenetic features of the chicken grunt, Parapristipoma trilineatum, small yellow croaker, Larimichthys polyactis, and brown croaker, Miichthys miiuy, in Jeju, Korea, karyotype analysis was performed. The karyotype of chicken grunt and brown croaker consists of 24 pairs of telocentrics [2n=48, fundamental number (FN)=48], and small yellow croaker consists of 3 pairs of submetacentrics and 21 pairs of telocentrics (2n=48, FN=54). No evidence of polymorphism, including aneuploidy or sex-related heteromorphic chromosomes, was found in any specimens examined in this study.

Comparative Analysis of Fluctuating Asymmetry between Ploidy and Sex in Marine Medaka, Oryzias dancena.

The purpose of this study is to examine fluctuating asymmetry of eye diameter, maxilla length, operculum length, and the number of pectoral fin ray and pelvic fin ray between ploidy and sex in diploid and triploid marine medaka, Oryzias dancena. In all experimental groups, eye diameter and maxilla length showed no significant difference between left side and right side (p>0.05). Results of operculum length in triploid male group and pectoral fin ray's number in diploid male group showed similarity ones with results of operculum length in triploid female group and pectoral fin ray's number in diploid female group (p<0.05). However, the operculum length in diploid male group and pectoral fin ray's number in triploid male group showed consinderable difference with those of operculum length in diploid female group and pectoral fin in triploid female group. Findings of pelvic fin ray's number in all groups were similar to those of pectoral fin ray's number in all groups (p<0.01).

Pysiological Responses of Diploid and Triploid Far Eastern Catfish, Silurus asotus to Water Temperature Stress.

The aim of study is to contribute to this knowledge-base by investigating the respiratory function, the metabolic rate and the difference of physiological responses un-der low water temperature (20℃→15℃) stress be-tween diploid and triploid far eastern catfish, Silurus asotus. During the 48 hrs of water temperature stress exposure time, the respiratory frequencies, CO2 and NH4+ concentrations of diploid had higher values than those of triploid (p<0.05). However, pH of triploid was higher than those of diploid (p<0.05), and oxygen consumption rate was not different between diploid and triploid (p>0.05). The level of plasma cortisol and plasma glucose of triploid was lower than those of the diploid (p<0.05). However, in case of lactic acid, there were not significant between triploid and diploid (p>0.05). These results suggest that diploid was more sensitive for low water temperature stress response than triploid in this species.

Morphometric Characteristics of Diploid and Triploid Marine Medaka, Oryzias dancena.

The morphometric truss characteristics and classical dimensions of the marine medaka, Oryzias dancena, that might distinguish diploid and triploid fish were examined. Significant differences in all the classical and truss dimensions of the diploid and triploid fish were observed in both sexes (p<0.01). All the dimensions of the triploid fish were greater than those of the diploid fish. The triploid marine medaka shows sexual dimorphism in these characters, and the sexual dimorphism of the triploid marine medaka is similar to that of the diploid marine medaka. Thus, when their classical dimension and truss dimension was measured, the growth of triploid marine medaka is faster than that of the diploid fish, and it displays clear sexual dimorphism, with male fish having longer dorsal and anal fins than female fish.

Temperature Dependent of Mitotic Interval for Grass Puffer, Takifugu niphobles.

The objective of this study was to determine the mitotic intervals (τ0) of two consecutive cell divisions and synchronous embryonic cleavage in grass puffer, Takifugu niphobles at different water temperatures (18, 20, 22, and 24℃). The color of the fertilized egg was light yellowish. The egg type was demersal and unadhesive. Egg weight was 0.09±0.002 mg. The sizes of unfertilized eggs were smaller than fertilized eggs in major axis and minor axis at 20℃ (p<0.05). The size of the fertilized egg of 18℃ water temperature group at the blastodisc stage was the smallest (p<0.05), but no significant differences were observed in the other water temperatures group except 18℃ water temperature group (p>0.05). The first cleavage stages at 18, 20, 22, and 24℃ were at 75, 90, 105, and 120 mins, respectively. As water temperature was increased, embryonic development and formation time of the first cleavage furrow were accelerated. There were negative correlation between τ0 and water temperature for grass puffer (Y=-1.225X+70.05, R2=0.988, n=10, where Y was τ0 and X was temperature). This study confirmed that successful hatching of grass puffer was related to water temperature. Chromosome manipulation will be helpful for this species using cleavage frequency and τ0.

The Effect of Sodium Nitrite Exposure on Physiological Response of Starved Far Eastern Catfish, Silurus asotus.

The experiment was conducted for 210 days to determine the effect of feeding, and starvation, and exposure to sodium nitrite (NaNO2) on the survival, physiological changes, hematological parameter, and stress response of Far Eastern catfish, Silurus asotus. The survival of the starved group was lower than that of the fed group during the experiment. Starvation resulted in retardation of growth, which provides an example of fish that failed to continue to grow and remain in a good condition. Blood analyses (cortisol and glucose) showed significant differences of stress response between the fed and starved groups exposed to NaNO2 at the conclusion of the experiment (p<0.05). These results suggest that all nutritional parameters used for starvation and feeding with NaNO2 stress in this experiment appear to be a useful index of nutritional status in Far Eastern catfish.

Starvation-induced Physiological Responses and RNA/DNA Ratios in Rock Bream, Oplegnathus fasciatus, and Olive Flounder, Paralichthys olivaceus.

In a 12-week experiment, the rock bream, Oplegnathus fasciatus, and olive flounder, Paralichthys olivaceus, were investigated to determine the effects of starvation on their physiological parameters. The protein and DNA contents of the starved fish were significantly higher than the initial values and those of the fed fish. The RNA contents and RNA/DNA ratios of the fed fish were significantly higher than those of the other groups (P<0.05). The hematocrit, hemoglobin, red blood cells (RBC), and mean corpuscular volume (MCV) of the fed rock bream were significantly higher than at baseline (P<0.05), whereas the mean corpuscular hemoglobin concentration (MCHC) of the fed fish was lower than at baseline (P<0.05). The hematocrit, hemoglobin, RBC, and MCHC of the starved group were significantly lower than the baseline values, whereas the MCV of the starved group was significantly higher than the baseline value (P<0.05). No significant difference in alanine aminotransferase was observed between the fed fish and baseline, whereas the starved fish value was significantly higher than the baseline value (P<0.05). There were no significant differences in cortisol levels. However, the glucose level in the fed group was significantly higher than the baseline level and that in the starved group was significantly lower than the baseline level (P<0.05).

Change of Various Characteristics between Spawning and Non-spawning Season in Diploid and Induced Triploid Far Eastern Catfish, Silurus asotus.

The purpose of this study is to investigate the differences fatty acids and hormonal parameters in the spawning and non-spawning season between the diploid and induced triploid Far Eastern catfish, Silurus asotus. The measured triploids were produced by cold shock for 50 min at 4℃ in May 2014, the spawning season of diploid was in May, and the non-spawning season was designated in January. Estradiol and testosterone and gonadosomatic index of diploid were higher than those of induced triploid in spawning season (P<0.05), and those of diploid in spawning season were higher than non-spawning season. On the other hand, thyroid stimulating hormone and thyroxine of induced triploid were higher than those of diploid in spawning season (P<0.05). Erythrocyte count of diploid was higher than that of induced triploid in spawning season and non-spawning seasons. Mean corpuscular volume and mean corpuscular hemoglobin of induced triploid were higher than those of diploid in both seasons (P<0.05). Percentages of total saturated fatty acids and n-3 polyunsaturated fatty acids of induced triploid were higher than those of diploid in spawning season, but those of diploid were higher in non-spawning season (P<0.05). Percentages of total mono unsaturated fatty acids and total n-6 polyunsaturated fatty acids of diploid were higher than those of induced triploids in spawning season, while those of induced triploid in non-spawning season were higher (P<0.05). Therefore, induced triploids in the spawning season tend to concentrate on growth and lipid-synthesization, whereas, diploids concentrate on reproduction and gonadal maturation rather than on growth. In non-spawning season, growth and lipid-synthesization were not significantly different between diploid and induced triploid.

Various Characteristics of Hybrid between River Puffer, Takifugu obscurus and Tiger Puffer, T. rubripes, and Their Hybrid Triploid.

A comparison of the growth, hematological values, fatty acids, and gonadal and growth hormonal changes of river puffer, Takifugu obscurus, tiger puffer, T. rubripes, their hybrids (river puffer × tiger puffer) and hybrid triploids was performed during 3 months of their early growth period. Several features were observed during these 3 months: hybrids showed the highest levels of specific growth rate, 1.48%; hybrid triploids showed the smallest change in viscera fat (P<0.05), but GSI was not significantly different among groups (P>0.05). Considering hematological parameters, hybrid triploids had increased mean corpuscular volume and mean corpuscular hemoglobin (P<0.05), but other parameters were not significantly different between groups (P>0.05). With respect to fatty acids, puffer fish, hybrids and hybrid triploids contained fatty acids such as SFAs, MUFAs, n-3 PUFAs and n-6 PUFAs. There were significantly different amounts of total fatty acids between groups (P<0.05), however, rates of changes in fatty acids did not differ significantly between groups (P>0.05). Gonadal hormone (estradiol and testosterone) changes in the river puffer and tiger puffer were significantly higher than that observed in hybrids and hybrid triploids. The hybrids and tiger puffers had higher amounts of growth hormone (thyroid stimulating hormone and thyroxine) than the hybrid triploids and river puffers (P<0.05).

Comparative Analysis of Tissue and Cell Cycle on the Far Eastern Catfish, Silurus asotus between Diploid and Triploid.

The influence of triploidization on histological characteristics of retina, trunk kidney, liver and midgut tissue, and cell cycle of tail fin and gill tissue in far eastern catfish, Silurus asotus were analyzed. In the infertile triploid fish, the nucleus and/or cell size of secondary proximal tubule cells of trunk kidney, hepatocyte and midgut epithelium are much larger than those of the corresponding cells in the diploid fish (P<0.05). However, triploid tissue showed fewer number of outer nuclear layer in retina and nuclei in secondary proximal tubule of trunk kidney than those for diploid tissue. The mean percentages of the Gl-, the S- and the G2+M-phase fractions were 92.5%, 3.2% and 4.3% in tail fin tissue of diploid, and 93.4%, 2.6% and 4.0% in those of triploid, respectively. There were no significant differences in the percentages of each cell cycle fraction between diploid and triploid. The mean percentages of each phase fractions were 75.1%, 11.1% and 13.8% in gill tissue of diploid and 85.2%, 8.9% and 5.9% in those of triploid, respectively. The differences of cell cycle between tail fin tissue and gill tissue were statistically significant in diploid and triploid (P<0.05). Also, the differences between diploid and triploid were statistically significant in tail fin tissue and gill tissue (P<0.05). Cyclin D1 and cyclin E expressions were not significantly difference between gill tissue and tail fin tissue, and protein expressions of induced triploid were higher than those of diploid. Results from this study suggest that some characteristics in the triploid exhibiting larger cell and nucleus size with fewer number of cell than diploid can be used as an indicator in the identification of triploidization and ploidy level in far eastern catfish.

Effects of Clove Oil and Lidocaine-HCl Anesthesia on Water Parameter during Simulated Transportation in the Marine Medaka, Oryzias dancena.

Optimum concentrations of anesthetic clove oil and anesthetic lidocaine-HCl were determined for a species of adult marine medaka, Oryzias dancena, over a range of salinity conditions, and investigated in a transport simulation experiment by analyzing various water and physiological parameters. Research indicated that the higher the concentration of anesthetic at each salinity, the shorter the anesthesia time at each salinity. At each concentration, fish were anesthetized slower at water salinities over 10 ppt (P<0.05). Anesthesia time at 10 ppt was faster than any other salinity. In 10 ppt salinity, the dissolved oxygen (DO) concentrations and respiratory frequencies of the clove-oil-administered groups decreased until 48 hours (P<0.05), whereas the NH4+ and CO2 concentrations increased until 48 hours (P<0.05). In same period, the DO, NH4+, and CO2 concentrations and respiratory frequencies all decreased as the clove oil concentration increased (P<0.05). The trends in the DO, NH4+, and CO2 concentrations and respiratory frequencies in the lidocaine-HCl-administered groups were similar to those in the clove-oil-administered groups. In conclusion, clove oil and lidocaine-HCl are effective anesthetics, improving the transportation of the marine medaka. The results from this study will contribute to safe laboratory handling of the marine medaka, which are commonly required by many research studies and experiments.

Morphometric Characteristic between Diploid and Spontaneous Triploid Carp in Korea.

We used flowcytometry to ploidy verification after that investigate difference between diploid and spontaneous triploid through the truss dimension and classical dimension at crucian carp, Carassius auratus, crucian carp C. cuvieri and common carp, Cyprinus carpio collected from Hangang river, Hantangang river, Imjingang river, Geumgang river, Yeongsangang river and Nakdonggang river, Korea. There were significant differences among the three species for the truss dimensions anterior origin of dorsal fin (2)× anterior origin of anal fin (5), 2× anterior origin of pelvic fin (6), 2× origin of pectoral fin (7), posterior origin of dorsal fin (3)×5, 3×6, and 3×7 (P<0.05). There were no significant differences among the three species in the truss dimensions dorsal fin length (2×9) and eye diameter (ED)(P>0.05). On the other hand, there were no significant differences in the several classical dimensions of each species (P>0.05). Three classical dimensions, most anterior extension of the head (1)×2, 1×6 and 2× most posterior scale in lateral line (4) did not differ between the C. auratus diploid and spontaneous triploid (P>0.05). Two classical dimensions, 1×6 and longest length between most anterior extension of the head and gill cover (1×8) did not differ between the C. cuvieri diploid and spontaneous triploid (P>0.05). One classical dimensions, 1×2 did not differ between the common carp diploid and spontaneous triploid (P>0.05). There were significant differences in the each diploid and triploid species (P<0.05). These results suggest that the classification of each species and classification between diploid and spontaneous triploid morphometrical parameters used in this study are useful indices of morphometrical status in the each species from major river of Korea.

Effects of Cryoprotectants and Diluents on the Cryopreservation of Spermatozoa from Far Eastern Catfish, Silurus asotus.

The aim of this study was to compare the efficacy of cryopreservation methods for ex situ conservation of spermatozoa from far eastern catfish, Silurus asotus. The spermatozoa activity index (SAI) and hatching rates were higher in spermatozoa stored in Alserver's solution than those of spermatozoa stored in glucose solution. The SAI and hatching rates in all experimental groups gradually decreased with increasing duration of storage. Additionally, the SAI and hatching rates gradually decreased with increasing thawing temperatures at all storage durations (P<0.05). Based on the SAI and hatching rates, our results suggest that the optimal cryopreservation conditions of catfish spermatozoa involve storage in Alserver's solution with 15% ethylene glycol, and thawing at 25℃. Cryopreservation of spermatozoa is a useful and reliable technique for conserving gene resources and for artificial propagation of far eastern catfish.