• Animal cells and systems
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• v.16 no.5
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• pp.425-430
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• 2012

The southwestern Australian frog Crinia georgiana (Anura; Myobatrachidae) inhabits ephemeral pools in which the tadpoles often face desiccation. Under these conditions selection on tadpoles can be severe and can directly affect fitness during the aquatic as well as the terrestrial developmental stages. A quantitative genetic study using a half-sib breeding design was conducted to understand the genetic effects on larval life-history traits. We found no significant additive genetic variance in any of larval traits. Except for hatching period, heritability estimates based on females were high in egg size, larval period, snout-vent length, and weight at metamorphosis, suggesting non-additive genetic effects. These results indicate that any response to selection during hatching and larval periods should be predominately governed by non-additive genetic effects in C. georgiana.

• Journal of Wetlands Research
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• v.17 no.4
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• pp.407-413
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• 2015

As the number of applications containing nanomaterials increase, aquatic ecosystem exposure to nanoparticles (NPs) is unavoidable. In this study, we carried out toxicity assessment to Au-nanoparticles(NPs) of Rana dybowskii eggs and tadpoles. Toxicity was recorded hatching rate, body condition(Snout-tail length, STL), and behavioral sensitivity. Behavioral sensitivity was analyzed to anti-predator behavior using Ethovision XT 9. Au-NPs did not show any toxicity of hatching rate and STL. But, Tadpoles exposed to Au-NPs decrease behavioral sensitivity of stimuli. This study has value of environmental toxicity evaluation because these results show the new way of toxicity assessment.

• Parasites, Hosts and Diseases
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• v.62 no.1
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• pp.145-150
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• 2024

It is uncertain when the head collar and collar spines of Isthmiophora hortensis (Digenea: Echinostomatidae), a zoonotic echinostome species in Far Eastern Asia, develop during its larval stages. In this study, the appearance of the head collar and collar spines was studied using light and scanning electron microscopy in cercariae and metacercariae experimentally obtained from freshwater snails (Lymnaea pervia) and tadpoles (Rana nigromaculata), respectively. The cercariae were shed from the snail on day 30 after exposure to laboratory-hatched miracidia. Metacercariae were obtained from the experimental tadpoles at 3, 6, 12, 15, 20, 24, 26, and 30 h after exposure to the cercariae. The head collar was already visible in the cercarial stage, although its degree of development was weak. However, collar spines did not appear in the cercarial stage and even in the early metacercarial stage less than 24 h postinfection in tadpoles. Collar spines became visible in the metacercariae when they grew older than 24 h. It was concluded that the head collar of I. hortensis developed early in the cercarial stage, but the development of collar spines did not occur until the worms became 24-h-old metacercariae in our experimental setting. Counting the number of collar spines was concluded as an unfeasible diagnostic method for I. hortensis cercariae when they are shed from the snail host.

• Parasites, Hosts and Diseases
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• v.26 no.3
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• pp.179-188
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• 1988

The life cycle of Fibricola seoulensis was studied in the laboratory and in the field, with special interests in the larval developments within the eggs and in the intermediate hosts. The first emergence of miracidia after incubation of eggs in 26C water began on the ninth day. The miracidia, elongate and cylindrical shape, had epidermal plates in the formula of 6, 9, 4 and 3, with two pairs of flame cells and lateral processes. A kind of fresh water snail, Hippeutis (H.) cantori, was found to shed furcocercous cercariae from the 13th day after experimental challenge with miracidia while Physa acute failed to shed. The same kind of snail collected from the field also shed the same cercariae. The cercariae were equipped with 2 pairs of penetration glands and 5 pairs of fame cells. The tadpoles of Rana nigromaculata were found susceptible to experimental infection with the cercariae. The same kind of tadpoles collected from various areas were also found naturally infected. The metacercariae in the tadpoles which were infected experimentally became infective to the definitive host in 21 days. The metacercariae were located free in the body cavity of tadpoles, and attained sexual maturity in rats in 7 days. The present study successfully followed the complete life cycle of F. seoulensis and found that it is possible to maintain the life cycle in the laboratory.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2000.05a
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• pp.512-512
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• 2000

Some planorbid snails such as Hippeutis cantori and Segmentina hemisphaerula have reported as the molluscan intermediate hosts of Neodiplostomum seoulense, one of important snail-borne human intestinal trematodes in Korea. However, one of the Korean lymnaeid snail species, Austropeplea ollular was also found to be the first intermediate ho of N. seoulense. In field-collected Austropeplea snails from Sorae and Kimpo out of se collected localities, the bifurcated cercariae of N. seoulense were shed (infection rat 0.3%), whereas no Radix auricularia and Fossaria truncatula were found shedding cercariae. Each of 12 tadpoles of Rana nigromaculata, known as the second intermedia host of N. seoulense, were exposed to 200 cercariae shed from field-collected A ollula. F tadpoles of R. nigromaculata were found to be massively infected with metacercariae o N. seoulense (recovery rate: 62.1%). Each of five rats (Sprague-Dowley strain) was or fed with 200 metacercariae, and eggs of N. seoulense were detected in the rat feces on week later. These rats were killed 4 weeks after postinfection and adult worms of N seoulense were recovered from the small intestines (recovery rate: 9%). This is the f report of A. ollula as the first molluscan intermediate host for N. seoulense in Korea.

• 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.

• Journal of Wetlands Research
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• v.10 no.2
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• pp.15-22
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• 2008

The role and distribution of fresh water algae was surveyed at Wangdeungjae Wetland of Mt. Jiri, a high mountain swampy land. Mean environmental factors were as follows; temperature was $17.6^{\circ}C$, pH was 6.3, conductivity was $24.6{\mu}S/cm$, TN was 0.6 mg/L, TP was 0.09 mg/L, and Chl-a was $11.9{\mu}g/L$, respectively. Algae were appeared 159 species(Chlorophyta 87, Bacillariophyta 56, Euglenophyta 11, and Cyanophyta 5). Desmid of Chlorophyta was 56 species, and dominant species was Aulacoseira distans of Bacillariophyta. To analyze food chain of the water ecosystem, we performed analysis of tadpole's stomach captured in the wetland. Tadpoles ingested mainly algae, and Aulacoseira distans was found in most quantity. Based on this study, algae take role of the primary producer as well as the prey of higher level predators(e.g. tadpoles) in the water ecosystem of Wangdeungjae Wetland.

• Parasites, Hosts and Diseases
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• v.49 no.4
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• pp.445-448
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• 2011

A survey was performed to find out the intermediate hosts of Gnathostoma nipponicum in Jeju-do (Province), the Republic of Korea. In August 2009 and 2010, a total of 82 tadpoles, 23 black-spotted pond frogs (Rana nigromaculata), 7 tiger keelback snakes (Rhabdophis tigrinus tigrinus), 6 red-tongue viper snakes (Agkistrodon ussuriensis), and 2 cat snakes (Elaphe dione) were collected in Jeju-do and examined by the pepsin-HCl digestion method. Total 5 gnathostome larvae were detected in 3 (50%) of 6 A. ussuriensis, 70 larvae in 3 of 7 (42.9%) R. tigrinus tigrinus, and 2 larvae in 2 of 82 (8.7%) frogs. No gnathostome larvae were detected in tadpoles and cat snakes. The larvae detected were a single species, and $2.17{\times}0.22mm$ in average size. They had characteristic head bulbs, muscular esophagus, and 4 cervical sacs. Three rows of hooklets were arranged in the head bulbs, and the number of hooklets in each row was 29, 33, and 36 posteriorly. All these characters were consistent with the advanced third-stage larvae of G. nipponicum. It has been first confirmed in Jeju-do that R. nigromaculata, A. ussuriensis, and R. tigrinus tigrinus play a role for intermediate and/or paratenic hosts for G. nipponicum.

• The Korean Journal of Zoology
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• v.21 no.2
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• pp.43-58
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• 1978

Heavy metal treatment on the fertilized frog eggs before the first cleavage results in a quantitative alteration in the number of PGCs. The formation of PGCs is inhibited by a limited range of heavy metal during the early embryonic development. Total doses of lead above 70ppm and doses of cadmium above 4ppm result in a partial reduction of germ cells at the mitotically dormant stage. After this stage the germ cell number increases almost at the same rate as the untreated control tadpoles. In contrast, on mercury treated eggs, total doses above 0.8ppm cause more damage to germ cell formation. Their proliferation rate thereafter seems to be lower compared with the others. These facts seem to suggest that the heavy metal treatment on frog eggs prior to the first cleavage division is not highly effective in the complete elimination of PGCs in constrast with UV irradiation, even though cytolysis of the tissue occurs in the tadpoles.

• Korean Journal of Environment and Ecology
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• v.30 no.1
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• pp.48-57
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• 2016

The distribution of fish (Cobitidae and Cyprinidae) and amphibians together with related environmental factors were surveyed at 30 randomly selected rice-fields (15 flooded unmanaged rice fields (FUR) and 15 unflooded managed rice fields (UMR)) near the Yedang reservoir in Korea, eight times from May to August in 2012. The total number of species captured from the entire survey area was 13 species with 8 families of fish and 5 species of amphibians. The number of species of Cyprinidae fish captured in FUR was higher than that in UMR. Upon the comparative analysis on the distribution of fish and amphibians in FUR and UMR, it was found that the number of Cyprinidae fish captured in FUR was significantly higher than that in UMR while the number of Cobitidae fish captured in UMR was higher than that in FUR. According to the analysis on the environmental factors that affect the distribution of fish, Cyprinidae fish tend to appear in rice-fields, that were flooded in winter, near the Yedang reservoir while Cobitidae fish tend to appear in rice fields that draws its water supply from forest reservoir and have a good water drainage system. In case of amphibians, the number of tadpoles captured in UMR was higher than that in FUR. Rana catesbeiana was dominant in FUR and Rana nigromaculata was dominant in UMR. Upon the analysis on the environmental factors that affect the distribution of tadpoles, it was found that Rana catesbeiana tadpoles tend to appear in rice fields, that were flooded in winter, near Yedang reservoir while Rana nigromaculata tadpoles tend to appear near mountains and far from the Yedang reservoir.