• Korean Journal of Environment and Ecology
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• v.38 no.2
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• pp.143-147
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• 2024

This study aimed to determine the egg-hatching period of boreal digging frogs, Kaloula borealis, and investigate whether the incubation temperature affects the hatching period. In this study, the egg hatching was recorded based on the appearance of the tadpole. The results of this study showed that all the eggs hatched within 48 hours after spawning, with 28.1% (±10.8, n=52) hatching within 24 hours and 99.9% (±0.23, n=49) within 48 hours after spawning. The mean hatching rate of tadpoles showed significant differences depending on the difference in water temperature. The mean hatching rate between 15 and 24 hours after spawning was higher at a water temperature of 21.1 (±0.2) ℃ than at 24.1 (±0.2) ℃. The results suggest rapid hatching occurs at relatively low water temperatures because the spawning habits that spawn eggs in temporary ponds or puddles in the rainy season require rapid hatching before the puddles dry out. The results of this study are helpful for understanding the most suitable temperature conditions for the incubation of eggs of the endangered species, boreal digging frog.

• Parasites, Hosts and Diseases
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• v.24 no.2
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• pp.109-114
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• 1986

In order to observe the growth and development of Fibricola seoulensis metacercariae, the tadpoles of Rana nigromaculata were experimentally infected with the cercariae. The meta cercariae of various developmental stages were recovered from the tadpoles after 2 to 65 days of infection. They were prepared for morphological observation, and were given orally to mice to observe their infectivity. The following results were obtained. 1. All of the tadpoles exposed to the cercariae were observed to harbour the larvae in their abdominal cavity. 2. The young metacercariae of 2 days after infection were $121.1{\mu}m$ long and $63.3{\mu}m$ wide. They grew linearly for the first 14 days to be $262.0{\mu}m$ long and $166.4{\mu}m$ wide. Thereafter, no more growth recognized until 65 days. 3. The larvae of 2 days old were similar with cercarial body and had 2 suckers, a pharynx, 2 ceca and a primordium of germ cells but no tribocytic organ. On the 8th day, they had tribocytic organ, and their morphology resembled that of mature metacercariae. 4. The metacercariae younger than 10 days could not infect the mice. Only the metacercariae older than 14 days had infectivity. The recovery rates increased by the age of metacercariae from 19.0% in 14 days old to 70.0% in 40 days old. Above findings indicate that the tadpole is indispensable for metacercarial development and it needs at least 2 weeks for maturation. The tadpole is a pivotal host in the life cycle of F. seoulensis for connection between the snail and the frog.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.20 no.2
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• pp.157-165
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• 1987

On January 16, 1986, mature adults of smooth lumpsucker, Aptocyclus ventricosus (Pallas) were collected from the coastal water of Okkye, Myongju-gun, Kangwon-do, Korea. The authors carried out artificial insemination on the boat. The eggs were incubated and the larvae were reared in laboratory. During the incubation period water temperature fluctuated between $7.5^{\circ}C$ and $21.4^{\circ}C$. The eggs of smooth lumpsucker are demersal and adhesive. The eggs diameters were varied from 2.28 to 2.36 mm. The hatching took place in ca. 725 hours after fertilization. The newly hatched larvae were 6.0-6.9 mm in total length. The features of the hatched larvae lie in the tadpole-like body form and in the well developed sucking disk, namely the ventral fins. 17 days after hatching, the larva attained 9.1 mm in total length. The gill opening retained a small opening at its upper part. Melanophores were developed on the tail. 31 days after hatching, the larva attained 10.6 mm in total length, and became juvenile. The first dorsal fin was disappeared. 105 days after hatching, the larvae attained 15.4-17.5 mm in total length.

• Parasites, Hosts and Diseases
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• v.28 no.3
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• pp.161-174
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• 1990

The complete life cycle of Spirometra erinacei has been experimentally maintained in the laboratory. The cyclops were reared as the first intermediate host, and the tadpoles of Rana nigromaculata as the second intermediate host. ICR mice were used as another second host. The experimental definitive hosts were dogs and cats. Maturation and hatching of the eggs took 8 to 14 days by incubation at 29℃. The coracidium measured 43.8×36.9㎛. Mesocyclops leuckarti and Eucyclops serrulatus were susceptible to the coracidial infection. The procercoids older than 5 days in the cyclops had minute spines at the anterior end, calcium corpuscles in the body parenchyme and the cercomer at the posterior end. Procercoids 10 to 20 days old were infective to tadpoles, and 15 or 21 day old worms could infect the mice. The plerocercoids from the tadpoles at 15 days after experimental infection were pear-shaped and shorter than 1 mm in the length and were infective to mice. Fifteen to 18 days after experiMental inoculation of plerocercoids to dogs or cats, the adult worms began to produce eggs. One life cycle from egg to egg needed 48 to 67 days in the laboratory. The morphology of larval or adult worms was compatible with the description of Spirometra erinacei.

• Parasites, Hosts and Diseases
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• v.29 no.2
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• pp.161-172
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• 1991

The complete life cycle of Echinostoma hertense has been maintained in the laboratory, using Lymnaea persia snails and Rana nigromaculata tadpoles as the first and second intermediate hosts. ICR mice was used as the definitive host. Within the egg of 5. hotense, the miracidium was fully matured in 13 days of incubation at $29~30^{\circ}C$. The miracidium was $93.8{\times}53.6{\;}{\mu\textrm{m}}$ in average size, covered with numerous cilia of $7~11{\;}{\mu\textrm{m}}$ length. The epidermal plates were arranged in 6-8-4-2 formula. The first generation rediae ($1.19{\times}0.27{\;}mm$ in average size) were observed in 14 days after miracidial challenge to the snails, and the second generation rediae ($1.40{\times}0.26{\;}mm$ in average size) in 30 days. The average sixte of the cercaria was $295.5{\times}145.0{\;}{\mu\textrm{m}}$. Their head crown was poorly developed, and collar spines were not yet observed. After a cercarial challenge to the tadpoles, all of the tadpoles became infected and the average worm recovery rate was 88.5%. The majority of the metacercariae (75.5%) were recovered from the muscle of the tadpole's posterior body and the rest (24.3%) from their gills. The metacercariae from the tadpoles were elliptical, and $167.7{\times}129.9{\;}{\mu\textrm{m}}$ in average size. The recovery rate of adults from the mice was difFerent by the age of the metacercariae grown in the tadpoles. The metacercariae younger than 5 hrs could not infect mice whereas those older than 6 hrs could infect mice. The recovery rate became higher as the metacercaria matured, with the peak recovery rate of 90.0 % at the metacercarial age of 9 days. Thereafter the recovery rate decreased to 55.0% at the age of 50 days. As shown by the above results, the whole life cycle of E. hcrtense has been completed in the laboratory. At least 55~58 days were required to maintain one egg-to-egg cycle of E. hortense.

• Journal of Aquaculture
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• v.3 no.1
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• pp.79-88
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• 1990

In order to obtain the basic data fir the effective seed production of sea squirt, Halocynthia roretzi(Drasche), the influence of water temperature and light intensity on spawning induction, egg development and seed settling were investigated during the Period from December 24, 1906 to February 24, 1987. The maximum number of eggs spawned was obtained at $14^{\circ}C$. The relationships between the water temperature (T, $^{\circ}C$) and the required time (h, hour) in each egg developmental stage were given as follows : Up to 8 cell 1/h =0.0147 T-0.0069(.=0.9816), Up to 32 cell 1/h =0.0100 T-0.0017(r=0.9672), Up to early tadpole 1/h =0.0043 T+0.0024(r=0.9913), Up to hatching larva 1/h =0.0021 T-0.0021 (r=0.9898). The highest rate of seed attachment was obtained at $14^{\circ}C$ of water temperature.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.37 no.6
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• pp.445-454
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• 2004

A search for contraction and relaxation responses on the smooth muscles, antimicrobial and antioxidant activity in different body parts of 4 freshwater fish and 4 marine fish were conducted. The four freshwater fish studied were Sarotherodon niloticus (tilapia), Channa arus (snake head), Cyprinus carpio (Israel carp) and Siluru osotus (catfish), and the four marine fish were Scyliorhinus torazame (tiger shark), Ateiepus japonicus (tadpole fish), Mugil cephalus (gray mullet) and Thamnaconus modestus (file fish). Frozen samples were extracted with distilled water containing $1{\%}$ acetic acid. Antimicrobial activity against Bacillus subtilis and Eschrrichia coli was detected in extracts from several tissues in all species tested. Relatively high antimicrobial activity could also be detected in the bile extracts from C. carpio, M. cephalus, and T. modestus. Contraction and relaxation responses on smooth muscles could be detected in all species tested, especially in the intestine extracts. Antioxidant activity was also detected in extracts from several tissues in all species tested, while in the extracts from S. osotus, excluding livers and spleens, no antioxidant activity was detected. Results from this study suggest that fish are a potential source for the discovery of novel bioactive materials.

• Korean Journal of Environment and Ecology
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• v.29 no.4
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• pp.533-538
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• 2015

This study was conducted to examine the effect of salinity on the early embryonic development stage of boreal digging frogs (Kaloula borealis). An experiment was carried out with the eggs of K. borealis mating couples laid along the coastal zone of Jeju Island in June 2013. The salinity was set to 0, 1, 3, 5, and 7 ‰, respectively. The survival and growth of the larvae at various stages from the egg phase to the closing of their external gills phase were observed. In another experiment, tadpoles in internal gill stage were placed in solutions with salinity of 0, 1, 3, 5, and 7 ‰, respectively, and their survival rate and growth rate were observed, and then the results of the two experiments above were compared. The results showed that in egg and external gill stage, there was no significant difference in survival rate in 3 ‰ solution, though there was low survival rate in 5 ‰ solution. Further, all the eggs were dead in 7 ‰ solution, so it appeared that solutions with salinity of 5 ‰ or higher affect the survival of K. borealis in the early embryonic development. Larvae in the internal gill stage showed no significant difference in survival rate from the control group up to a salinity of 5 ‰, but when placed in a solution of over 7 ‰ salinity, the survival rate decreased. The growth rate also slowed down with the higher salinity. It appeared that in both the external gill stage and the internal gill stage in 5 ‰ solution, the growth rate decreased significantly compared to the control group. From this study it is concluded that higher salinity values have a significant impact on the survival and growth of the K. borealis larvae and this finding can be used to conserve K. borealis species that are decreasing in number due to the side effects of development in coastal areas.

• Journal of Wetlands Research
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• v.20 no.3
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• pp.272-280
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• 2018

Existing toxicity assessment researches were rarely studied on assessment of the abnormal behavior that affecting survival. Therefore, the study used anti-predator response of amphibians larvae, based on behavioral understanding, to assess toxicity in fullerene nanowhisker(FNW) and fullerene nanowhisker-silver nanoparticle composites(FNW-Ag). The experiment was conducted by dividing the groups not exposed to nanomaterials and exposed to nanomaterials at five concentrations(FNW: $10{\mu}g/ml$, FNW: $100{\mu}g/ml$, FNW: $500{\mu}g/ml$ FNW-Ag: $10{\mu}g/ml$, FNW: $50{\mu}g/ml$). As a result, there were no differences in normal activity except those exposed to concentrations of FNW-Ag $50{\mu}g/ml$, but there were statistically significant differences in anti-predator response except those exposed to concentrations of FNW $10{\mu}g/ml$. That is, exposed of nanomaterials does not affect ordinary movements, but analyses based on behavioral understandings have shown that it has an influence on the anti-predator response. It is therefore considered necessary to have animal behavioral analysis method performed in the assessment of eco-toxic experiment.

• Journal of the Korean Society of Radiology
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• v.84 no.3
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• pp.736-744
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• 2023

Adult-onset Alexander Disease (AOAD) is a rare genetically determined leukoencephalopathy that presents with ataxia, spastic paraparesis, or brain stem signs including speech abnormalities, swallowing difficulties, and frequent vomiting. The diagnosis of AOAD is frequently proposed based on the findings on MRI. We demonstrate two cases (37-year-old female and 61-year-old female) with characteristic imaging findings and changes in follow-up MRI in patients with AOAD, which were confirmed via glial fibrillary acidic protein (GFAP) mutation analysis. On MRI, the typical tadpole-like brainstem atrophy and periventricular white matter abnormalities were noted. The presumptive diagnoses were made based on the typical MRI appearances and, subsequently, confirmed via GFAP mutation analysis. Follow-up MRI demonstrated the progression of atrophy in the medulla and upper cervical spinal cord. Our report could help raise awareness of characteristic MRI findings of AOAD, thus helping clinicians use GFAP analysis for AOAD diagnosis confirmation.