• Parasites, Hosts and Diseases
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• 제46권4호
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• pp.285-288
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• 2008

To examine the infection status of freshwater fish with Gnathostoma spp. larvae in Myanmar, we purchased 15 snakeheads, Channa striatus, from a local market in a suburban area of Naypyidaw, the new capital city. Two larval gnathostomes were collected using an artificial digestion technique, and observed by a light microscope and a scanning electron microscope. The size of an intact larva was 2.65 mm long and 0.32 mm wide. The characteristic morphology of the larvae included the presence of a long esophagus (0.80 mm long), 2 pairs of cervical sacs (0.43 mm long), and a characteristic head bulb with 4 rows of hooklets. The number of hooklets in the 1st, 2nd, 3rd, and 4th row was 45, 48, 50, and 52, respectively. Based on these morphological characters, the larvae were identified as the advanced 3rd-stage larvae of Gnathostoma spinigerum. This is the first report of detection of G. spinigerum 3rd-stage larvae in the central part of Myanmar. Our study suggests that intake of raw meat of snakehead fish in Myanmar may result in human gnathostomiasis.

• 한국양식학회지
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• 제12권1호
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• pp.15-24
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• 1999

1997년 1월부터 5월까지 전라남도 완도 연안에서 연승어업에 의해 채집된 붉은쏨뱅이 어미들을 육상수조로 운반하여 체내에서 수정된 난을 인위적으로 채란하여 난의 형태를 관찰하였고, 산출자치어의 성장에 따른 형태변화를 관찰하였다. 1. 붉은쏨뱅이의 수정란 및 미수정란은 구형으로 무채투명하여, 이경은 0.72~0.80mm(평균 0.75mm, n=50)이고, 큰 유구 하나와 작은 유구 2~7개가 분포한다. 2. 산출직후의 자어는 전장이 3.79~3.97mm이며, 입과 항문이 열려있고, 눈에 색소포가 착색되어있다. 3. 산출 1~2일째의 자어는 전장이 3.90~4.13mm으로 난황을 완전 흡수하여, 아래턱에 처음으로 흑색소포가 출현한다. 4. 산출 11일째 자어는 성장이 4.23~4.60mm으로 가슴지느러미에 9~10개의 줄기가 출현하며, 후두부에 나뭇가지모양의 흑색소포가 나타난다. 5. 산출 21일째 자란은 전장이 5.83~7.10mm으로 통색말단이 $45^{\circ}$ 각도로 굽어진다. 6. 산출 33일째 개채의 전장은 9.80~12.36mm으로 모든 지느러미 줄기가 정수에 달하여 치어기로 이행한다.

• 한국어류학회지
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• 제35권1호
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• pp.10-19
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• 2023

본 연구는 민물검정망둑의 초기생활사를 규명하고 그 특징을 근연종과 비교하여 분류학적 기초자료를 마련하고자 실시하였다. 수정란은 부착사를 가진 전구형으로 크기는 장경 1.30 mm, 단경 0.79 mm였다. 난발생은 수온 23.0~25.0℃에서 부화까지 167~228시간이 소요되었다. 부화 직후 난황자어는 전장 2.31~2.78 mm였고, 난황과 유구를 가지고 있었다. 부화 후 3일째는 전장 2.84~3.10 mm로 난황흡수가 완료되면서 전기자어로 이행하였다. 부화 후 19일째는 전장 4.02~4.62 mm로 꼬리지느러미 끝이 위쪽으로 휘어지면서 중기자어로 이행하였다. 부화 후 30일째는 전장 5.04~6.36 mm로 척추 끝 미부봉상골이 45°로 휘어지면서 후기자어로 이행하였다. 부화 후 54일째는 전장 7.43~9.84 mm로 기조 수가 각 부위별 지느러미 기조 수는 제1 등지느러미 6개, 제2등지느러미 12개, 뒷지느러미 11개, 배지느러미 10개로 정수에 달하면서 치어기로 이행하였다. 연구결과 민물검정망둑은 검정망둑속 가운데 수정란이 크고 부화자어의 근절 수가 많은 것을 새롭게 확인하였고, 흑색소포 분포위치는 검정망둑속 어류들과 다르게 나타나 형태적으로 쉽게 구분할 수 있었다.

• 한국어류학회지
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• 제30권1호
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• pp.9-17
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• 2018

겨울철 환경에 대한 초기 적응을 조사하기 위해 대구(Gadus macrocephalus), 꼼치(Liparis tanakae), 노래미(Hexagrammos agrammus) 자어의 부화 직후와 첫 섭식 시 외부형태, 소화기관, 유영능력의 발달을 확인하였으며, 다른 계절에 부화하는 어종과 비교하였다. 평균 전장(${\pm}SD$)은 대구 $4.35{\pm}0.11mm$, 꼼치 $5.26{\pm}0.08mm$, 노래미 $7.48{\pm}0.35mm$로 부화 시 다른 계절 부화자어에 비하여 컸으며, 세 어종 모두 초기소화기관을 갖춘 후 부화하여 다른 계절 부화자어에 비해 초기소화기관 확립시기가 빨랐다. 대구, 꼼치, 노래미의 첫 섭식 시기가 부화 후 3일, 2일, 0일이었고, 난황을 갖고 있는 기간이 5일 이상으로 다른 계절에 부화하는 자어에 비해 혼합섭이기간이 비교적 길었다. 이 3종 자어의 유영능력은 다른 계절 부화자어에 비해 순항유영속도와 돌진유영속도 모두 부화 직후부터 빨랐다. 이러한 특징들은 자어가 생존하기 어려운 겨울철 환경에 대한 자연선택 및 환경적응의 결과로 생각된다.

• Mycobiology
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• 제35권3호
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• pp.159-161
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• 2007

Pine tree death caused by pine wood nematode(PWN) involves phoretic relationships between PWN and its vector Japanese pine sawyer beetle(JPS). In an effort to understand the diversity of fungi involved in PWN life cycle, a total of 176 fungal isolates were collected from PWNs, adults and larvae of JPS, PWN-diseased Japanese black pine that was cut down in 2005 at Jinju, Korea. Based on microscopic observation and colony morphology, and sequence analysis of the ITS rDNA, the fungal isolates were identified at the level of genus. Three genera including Mucor, Ophiostoma, and Penicillium were identified from PWN. Two genera of Ophiostoma and Penicillium were discovered from JPS larvae. Frpm JPS adult beetles, nine genera of Aspergillus, Gibberalla, Hypocrea, Irpex, Leptosphaeria, Ophiostoma, Penicillium, and Plectosphaerella and unknown basidio-mycetes were found. Ten genera from PWN-infected weed were confirmed as Bionectria, Botrytis, Camarops, Fusarium, Hypocrea, Nectria, Mucor, Ophiostoma, Penicillium, and Trichoderma. Penicillium and Ophiostoma were commonly distributed on PWN and its vector and host. This is first report of the fungi associated with PWN and its vector and host in Korea.

• Fisheries and Aquatic Sciences
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• 제16권2호
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• pp.125-129
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• 2013

Vibrio ichthyoenteri is a facultatively anaerobic gram-negative bacterium with straight or slightly curved rod morphology. The bacterium is an etiological agent of bacterial enteritis of Olive flounder Paralichthys olivaceus. Only a handful of studies, using a limited number of isolates, have investigated the phenotypic and genetic characteristics of V. ichthyoenteri. We isolated 40 V. ichthyoenteri strains, identified based on the 16S rRNA gene sequence, from the diseased flounder larvae and investigated the API 20E and ZYM profiles. The isolates exhibited highly divergent phenotypic characteristics regardless of sampling time point and location, and fish age. Essential enzymes produced by V. ichthyoenteri seemed to be alkaline phosphatase, leucine arylamidase, and N-acetyl-${\beta}$-glucosaminidase. This study reveals a much greater enzymatic and biochemical phenotype diversity than has been evident to date. These results suggest that a given population of V. ichthyoenteri could be heterogeneous in terms of its phenotypic characteristics.

• 대한의생명과학회지
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• 제24권2호
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• pp.125-129
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• 2018

Megaselia scalaris, also known as the scuttle fly, has a humpbacked morphology and was categorized as an insect undergoing complete metamorphosis. Megaselia scalaris was reported to be found in diverse environments. Recently, the scuttle fly has been a focus of studies by forensic scientists, geneticists, and developmental biologists. However, detailed research into scuttle fly development is still unclear. Therefore, the current study has been performed to elucidate the development of Megaselia scalaris. The scuttle fly undergoes four distinct stages of development: egg, larva, pupa and adult fly. After mating, the scuttle fly eggs hatch within one day and become larvae. The newly generated larvae go through 1, 2, and 3 instar stages within a period of 5~10 days. The instar stage 1 takes 1~2 days, instar stage 2 takes 1~2 days, and instar stage 3 takes 3~5 days. Depending on the environmental temperature, the pupae stage takes approximately 10~15 days to complete. The pupa stage can be divided into five sub-stages: 1~3 days, 4~6 days, 7~9 days, 10~12 days and 13~15 days. After molting, the newly formed adult scuttle fly can fly after one day. The morphological characteristics of the scuttle fly during each stage of development was detailed within this study.

• 한국수산과학회지
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• 제32권2호
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• pp.134-138
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• 1999

1997년 3월에 부산시 민락동 어시장에서 채집한 등줄숭어 어미들을 실험실로 운반하여 인위적인 방법으로 난을 수정시킨 후, 난의 형태, 난발생과정 및 자어의 성장에 따른 형태변화를 관찰하였다. 1. 등줄숭어의 수정란은 무색투명한 원형의 분리부성란으로, 난경은 0.95$\~$1.06mm이고 부화에 소요된 시간은 수정후 $16.0^{\circ}C$에서 73시 간이였다. 2. 부화 직후의 자어는 전장 1.72$\~$1.92mm로 입과 항문은 열리지 않고, 근절은 19개로 아직 정수에 달하지 않았으며, 몸에는 막대기 모양의 흑색소포가 산재한다. 3. 부화후 5일째의 자어는 전장 2.27$\~$2.49mm로 입이 최초로 열리며 동시에 난황이 완전히 흡수되어 후기자어로 이행한다.

• International Journal of Industrial Entomology and Biomaterials
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• 제5권1호
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• pp.79-83
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• 2002

The wild silkmoth, Actias gnoma was firstly collected at Suwon located in the middle part of Korea. The developmental and morphological characteristics of A. gnoma reared under the laboratory conditions were analysed. The egg shape was shorter elliptic. The major and minor diameter of the eggs were 2.04 mm and 1.83 mm, respectively. White mucous material was remained inside the eggs after hatching. Also, the body color of the larvae was completely changed from dark brown to light yellowish-green at the 3rd instar, but it did not occur until pupation. In the feeding test on several plants, the oak tree, Quercus acutissima, was newly identified as a host plant. The final larval instar was mostly 6th, but in some larvae it was 7th. A few of larvae ate their own casts just after ecdysis. The whole larval duration ranged from 45 to 59 days. The single cocoon weight, cocoon shell weight and cocoon shell percentage were 1.65 g,31.3 cg and 18.9%, respectively, The cocoon shape and color were spindle and light brown, respectively. The morphology of the silk gland was greatly different from those of Bombyx mori, Antheraea yamamai and Antheraea peryi: the thickness of the middle and posterior silk glands was almost identical.

• 대한수의학회지
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• 제33권4호
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• pp.679-691
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• 1993

As a series of studies to investigate the effect of immunosuppression on Ascaris suum infection in undefinitive hosts, a delicate relationship between host and parasite, rabbits were divided into experiment 1(control group) and experiment 2(immnunosuppressive group treated with prednisolone acetate) and inoculated with a single dose of 5,000 embryonated A suum eggs. The recovery rates, sizes and morphology of the larvae and immunological responses in the rabbits were chronologically monitored according to somatic migration. In both experiments, the larvae failed to develop into the adults, but young adults in the experiment 2 grew somewhat faster and survied later than those in the experiment 1. The mast cells of small intestinal mucosa and mesenteric lymph nodes and the goblet cells of small intestinal mucosa in the worm detected cases of experiment 2 decreased remarkably in number comparing with those of experiment 1. Considering the experimental results. the expulsion mechanism of somatic migrant larvae may he related to the temporary increasing tendency of the mast cells, the goblet cells, T-cells of mesenteric lymph nodes and spleens, eosinophils in peripheral blood, degranulation rates of peritoneal mast cells and the migration inhibition rates of leucocytes. In addition, patent infection of A suum in the rabbits was not obviously observed despite of immunosuppression by prednisolone acetate.