• Parasites, Hosts and Diseases
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• 제29권2호
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• pp.161-172
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• 1991

실험실 내에서 호르텐스극구흡충(Echinostoma hortense)의 생활사를 유지하면서 여러 가지 생물학적 현상을 관찰하였다. 충란은 $29~30^{\circ}C$ 항온기에서 배양 약 13일에 miracidium으로 발육하였고, miracidium은 평균 $93.8{\times}53.6{\;}{\mu\textrm{m}}$의 크기였으며 체표에 $7~11{\;}{\mu\textrm{m}}$ 길이의 섬모가 덮혀 있었다. Miracidium을 패류 Lymnaea pervia에 접촉 감염시켰던 바, 접촉 후 14일에 평균 $1.19{\times}0.27{\;}mm$ 크기의 제 1기 redid로, 30일에는 평균 $1.40{\times}0.26{\;}mm$ 크기의 성숙한 제 2기 redid로 발육하였다. Cercaria는 평균 $295.5{times}145.0{\;}{\mu\textrm{m}}$의 크기였으며, 두관의 발육이 미약하였고 두극이 관찰되지 않았다. 올챙이에 이 cercaria를 접촉시킨 결과, 모든 올챙이가 감염되었으며 피낭유충 회수율도 평균 88.5%로 높았다. 올챙이로부터 회수한 피낭유충은 타원형이었으며 평균 $167.7{\times}129.9{\;}{\mu\textrm{m}}$의 크기였다. Cercaria감염 후 올챙이 체내에 약 12시간 동안 머문 피낭유충은 마우스에 대한 감염력이 5.0%였으나 점차 증가하여 9일간 머문 것은 90.0%로 최대치를 보였고 이후 감소하여 50일 머문 것은 55.0%의 감염력을 보였다. 피낭유충이 마우스 체내에서 성충이 되기까지는 약 11~12일이 소요되었다. 이상과 같이 실험실 내에서 E. hortense의 전 생활사를 완료시키는 데에 최소한 55~58 일이 소요되었다.

• 한국어업기술학회:학술대회논문집
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• 한국어업기술학회 2002년도 추계 수산관련학회 공동학술대회발표요지집
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• pp.243-244
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• 2002

연체동물, 복족강의 소화기관에 관한 연구는 20세기 초 Graham (1932, 1939)을 시작으로 많은 연구자들에 의해 형태 및 구조적 측면의 연구가 수행되어져 왔다(Graham, 1941,1964, 1973; Lutfy and Demian,1967; Bevelander, 1988). 복족류 소화관의 점막상피층을 구성하는 세포들의 종류 및 조직학적 특징에 대해서 Boer and Kits (1990)는 Lymnaea stagnaiis를 대상으로 소화관의 조직화학적인 방법과 미세구조적인 연구를 통하여 이들 소화관의 내강 상피조직이 섬모세포와 미세융모 그리고 다양한종류의 선세포들로 구성되어 있음을 보고한바 있다. (중략)

• Parasites, Hosts and Diseases
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• 제52권6호
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• pp.645-652
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• 2014

Fasciola hepatica is a trematode that causes zoonosis mainly in cattle and sheep and occasionally in humans. Fascioliasis has been reported in Korea; however, determining F. hepatica infection in snails has not been done recently. Thus, using PCR, we evaluated the prevalence of F. hepatica infection in snails at 4 large water-dropwort fields. Among 349 examined snails, F. hepatica-specific internal transcribed space 1 (ITS-1) and/or ITS-2 markers were detected in 12 snails and confirmed using sequence analysis. Morphologically, 213 of 349 collected snails were dextral shelled, which is the same aperture as the lymnaeid snail, the vectorial host for F. hepatica. Among the 12 F. hepatica-infected snails, 6 were known first intermediate hosts in Korea (Lymnaea viridis and L. ollula) and the remaining 6 (Lymnaea sp.) were potentially a new first intermediate host in Korea. It has been shown that the overall prevalence of the snails contaminated with F. hepatica in water-dropwort fields was 3.4%; however, the prevalence varied among the fields. This is the first study to estimate the prevalence of F. hepatica infection using the vectorial capacity of the snails in Korea.

• International Journal of Industrial Entomology and Biomaterials
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• 제4권2호
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• pp.163-168
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• 2002

We report for the first time the cDNA sequence encoding a ferritin subunit from the spiders Araneus ventricosus. The complete cDNA sequence of A. ventricosus ferritin subunit comprised 516 bp with 172 amino acid residues. The A. ventricosus ferritin subunit cDNA contained a conserved iron responsive element sequence in the 5 untranslated region. An alignment of the deduced protein sequence of the A. ventricosus ferritin subunit gene to that of other heavy chain ferritin molecules showed that A. ventricosus ferritin subunit is most similar to the great pond snail, Lymnaea stagnalis, ferritin with 70.2% of protein sequence identity.

• 대한수의학회지
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• 제27권2호
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• pp.291-299
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• 1987

The cattle liver flukes were collected at daughter house and classified with gross morphology. The hepatica type was only 14 flukes (4.7%) and the gigantica type was 284 flukes (95.3%) among total 298 flukes collected. In order to determinate the intermediate host of the flukes, artificial infection with the miracidia to snail hosts, Radix auricularia and Austropelea ollula, were successfully carried out, but the development in the later was terminated at the sporocyst stage. Intermediate host of the cattle flukes used to hibernate in deep part of the stubbles of rice pady. The number of A. ollula that has been collected from a rice stubble was ranged 0 to 19. Their mean number was 7 snails per the stubble. In artificial infection with miracidia, the reasonable number of them were 1 to 9 and the snail size was 2 to 5mm in length. The productivility of metacercaria in the intermediate host was observed. The metacercarial production per snail was ranged 5.5 to 48.0 per one miracidium.

• 한국기후변화학회지
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• 제6권3호
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• pp.167-173
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• 2015

The purpose of study is to identify trophic pathways from organic matter to macroinvertebrates in terms of the consumer and to characterize the food webs in an intermittent stream system of the Echi River in Japan. The ${\delta}^{13}C$ values of macroinvertebrates and their potential food sources indicated the scraper (Psephenoides spp., Ecdyonurus levis) and collector-gatherer (Ephemera strigata, Paraleptonphlebia chocolata) feed on periphyton and POM (particulate organic matter) in situ. Davidius lunatus, and Hexatoma spp., which were identified as predators, may feed upon Ephemera strigata and Stenelmis larvae, respectively. At station characterized by seepage water, the ${\delta}^{15}N$ values of Ecdyonurus levis, Lymnaea auricularia, and Rhyacophila nigrocephala larva probably showed relatively lower values according to its diets. Even in homogenous species, the trophic pathways of macroinvertebrates in situ exhibited considerable variation; this reflected the trophic pathways from organic matter to the consumer depending on habitat characteristics in stream.

• Parasites, Hosts and Diseases
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• 제53권1호
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• pp.59-64
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• 2015

This study was conducted to investigate the life history, morphology, and maturation of larval stages and adult worms of Fasciola gigantica in experimental mice. Lymnaea auricularia rubiginosa was used as the intermediate host, and Oryza sativa was used for encystment of the metacercariae, while Mus musculus was used as the definitive host for maturation study. Fresh eggs from the gall bladder of water buffaloes fully developed into embryonated ones and hatched out at days 11-12 after incubation at about $29^{\circ}C$. Free-swimming miracidia rapidly penetrated into the snail host, and gradually developed into the next larval stages; sporocyst, redia, and daughter redia with cercariae. Fully-developed cercariae were separated from the redia and shed from the snails on day 39 post-infection (PI). Free-swimming cercariae were immediately allowed to adhere to rice plants, and capsules were constructed to protect metacercariae on rice plants. Juvenile worms were detected in intestines of mice at days 3 and 6 PI, but they were found in the bile duct from day 9 PI. Juvenile and adult flukes were recovered from 16 mice experimentally infected with metacercariae, with the average recovery rate of 35.8%. Sexually mature adult flukes were recovered from day 42 PI. It could be confirmed that experimentally encysted metacercariae could infect and develop to maturity in the experimental host. The present study reports for the first time the complete life history of F. gigantica by an experimental study in Thailand. The obtained information can be used as a guide for prevention, elimination, and treatment of F. gigantica at environment and in other hosts.

• 자원환경지질
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• 제56권2호
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• pp.185-199
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• 2023

This study aimed to predict the effects of water ecology on the supply of hydrothermal energy to model a housing complex in Eco Delta Smart Village in Busan. Based on the results, engineering measures were recommended to minimize problems due to possible temperature variations on the supply of hydrothermal energy from the river. The current distribution of fish, benthic macroinvertebrates, and phytoplankton in the Pyeonggang Stream was monitored to determine their effects on water ecology. In the research area, five species and three families of fish were observed. The dominant species was Lepomis macrochirus, and the subdominant species was Carassius auratus. Twenty-five species and 21 families of benthic macroinvertebrates were found. The distribution of aquatic insects was poor in this area. The dominant species were Chironomidae sp., Lymnaea auricularia, Appasus japonicus, and Caridina denticulata denticulata in February, May, July, and October. Dominant phytoplankton were Aulacoseira ambigua and Nitzschia palea in February and May. Microcystis sp. was dominant in July and October. The health of the ecology the Pyeonggang Stream was assessed as D (bad) according to the benthic macroinvertebrate index (BMI). Shifts in the location of the discharge point 150 m downstream from intake points and discharge through embedded rock layer after adding equal amounts of stream water as was taken at the beginning were suggested to minimize water temperature variations due to the application of hydrothermal energy. When the scenario (i.e., quantity of water intake and dilution water, 1,600 m³/d and water temp. difference ±5 ℃) was realized, variations in water temperature were assessed at -0.19 ℃ and 0.59 ℃ during cooling and heating, respectively, at a point 10 m downstream. Water temperatures recorded at -0.20 ℃ and 0.68 ℃ during cooling and heating, respectively, at a point 10 m upstream. All stream water temperatures after the application of hydrothermal energy recovered within 24 hours. Future work on the long-term monitoring of ecosystems is suggested, particularly to analyze the influence of the water environment on hydrothermal energy supply operations.

• Parasites, Hosts and Diseases
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• 제62권1호
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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.