• 한국어병학회지
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• 제23권2호
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• pp.145-153
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• 2010

내용은 2009년 하반기, 우리나라 남해안(고흥, 나로도)과 서해안(선재도, 파도리)의 네 지점에서 시료채취 한 바지락에서의 Perkinsus olseni 감염에 대한 모니터링 결과로, 이전에 국제수역사무국(OIE)의 manual에서 지정하던 P. olseni에 대하여 특이적인 primer set으로 사용한 PCR 분석 결과와 2009년에 새로이 지정하는 P. olseni에 대하여 특이적인 primer set을 사용한 분석 결과를 비교하고, 결과를 통한 P. olseni의 검출율을 조사하였다. 특히 2009년에 새로이 지정된 PolsITS-140F와 PolsITS-600R의 primer set을 사용한 결과는 신속한 검출여부 분석에 적합한 것으로 생각되었다. P. olseni의 검출경향은 파도리에서 가장 낮았으며, 고흥에서 가장 높았다. 파도리의 7월, 8월 그리고 12월의 결과를 제외하고는 전 지점에서 7월에서 12월까지 지속적으로 높은 검출율을 나타내었다. PolsITS-140F와 PolsITS-600R의 primer set을 이용한 PCR 산물의 염기서열을 분석한 결과, 선재도의 결과에서 두 군데의 염기차이를 나타내는 것 이외에는 모두 같은 것으로 확인되었다.

• 한국양식학회지
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• 제18권3호
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• pp.207-214
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• 2005

We report on the diagnosis, pathology, and taxonomy of Perkinsus sp. infection in Manila clams (Ruditapes philippinarum) from Korean waters. Amplimers were designed from internal portions of the non-transcribed spacer (NTS) of P. atlanticus for molecular diagnosis of Perkinsus infection. PCR-based identification methods and an in situ hybridization assay were developed for detection of Perkinsus sp. in live tissues as well as in histological preparations. Hybridization signals were observed around the nucleus of trophozoites. Positive results from PCR and in situ hybridization indicated that Korean Perkinsus sp. is genetically identical with P. atlanticus reported in Europe, which is currently synonymous with P. olseni reported from Australia. Microscopic morphological features of different lift stages of Perkinsus sp. appeared very similar to those of P. atlanticus. Severely infected clams often exhibited white nodules on their mantles and gills as a consequence of inflammation. In lightly to moderately infected clams, Perkinsus sp. was mainly found in gill tissues, whereas the protozoan parasites were found in digestive tracts, gonadal tissues, and foot tissues of heavily infected clams. It is likely that the gills are the portal of the infection and that P. olseni spreads to other tissues as the infection advances. In conclusion, by considering the taxonomic priority of P. olseni, Korean Perkinsus sp. is accepted as P. olseni. P. olseni appears to be common on tidal flats on the western and southern Korean coasts and is considered to be a pathogen capable of causing mass mortality of clams.

• 한국패류학회지
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• 제28권1호
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• pp.65-71
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• 2012

Perkinsus spp.는 국내를 비롯한 전 세계에 걸쳐 수산업적으로 중요한 이매패류에 감염되어 대량폐사를 유발하는 대표적 기생충이다. 본 연구에서는 바지락에서 검출되는 P. olseni의 유주자를 광학현미경과 주사전자현미경을 이용해 미세구조를 관찰한 결과 P. olseni의 유주자는 타원형의 몸체에 1개의 장편모와 1개의 단편모로 구성되어 있었으며, 장편모에는 섬모털을 보유하고 있었으며, 섬모털은 편모의 한쪽 면에만 분포하고 있었다. 유주자의 평균 체장은 $3.37{\pm}0.33{\mu}m$, 체폭은 $1.72{\pm}0.22{\mu}m$ 이었으며, 장편모는 $16.34{\pm}1.52{\mu}m$, 단편모는 $8.25{\pm}1.39{\mu}m$으로 측정되었다. 이는 유럽과 미국에서 보고된 Perkinsus spp.와 비교 하였을 때 몸체의 크기는 작지만 편모의 길이는 긴 것으로 확인되었다.

• 한국패류학회지
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• 제27권4호
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• pp.387-393
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• 2011

The objective of this study was to develop a real-time PCR method for the rapid detection and quantification of the protozoan pathogen Perkinsus olseni using a TaqMan probe. For the standard, genomic DNA was extracted from $10^5$ in vitro-cultured P. olseni trophozoites, and then 10-fold serial dilutions to the level of a single cell were prepared. To test the reliability of the technique, triplicates of genomic DNA were extracted from $5{\times}10^4$ cells and 10-fold serial dilutions to the level of 5 cells were prepared. The standards and samples were analyzed in duplicate using an $Exicycler^{TM}$ 96 real-time quantitative thermal block. For quantification, the threshold cycle ($C_T$) values of samples were compared with those obtained from standard dilutions. There was a strong linear relationship between the $C_T$ value and the log concentration of cells in the standard ($r^2$ = 0.996). Detection of DNA at a concentration as low as the equivalent of a single cell showed that the assay was sensitive enough to detect a single cell of P. olseni. The estimated number of P. olseni cells was similar to the original cell concentrations, indicating the reliability of P. olseni quantification by real-time PCR. Accordingly, the designed primers and probe may be used for the rapid detection and quantification of P. olseni from clam tissue, environmental water, and sediment samples.

• 한국패류학회지
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• 제26권3호
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• pp.211-215
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• 2010

퍼킨서스편모충 P. olseni는 우리나라 바지락의 대부분이 감염되어 있으며 극심한 염증을 유발하는 우리나라 바지락의 대표적 기생충이다. 본 연구에서는 퍼킨서스편모충의 생태학적 특성을 조사하고자 영양체에서 휴면포자로 전환되는 과정과 유주자를 형성하는 과정에서 수온과 염분이 미치는 영향을 조사하였다. 조사결과 영양체에서 휴면포자로의 유도는 수온이 높을수록 유도율이 높고 휴면포자의 직경이 커지는 현상이 관찰되었다. 또한 유주자 형성은 고수온, 고염분의 환경에서 잘 형성됨으로써 $10^{\circ}C$ 이하에서는 유주자 발생이 이루어지 않으며, 10 ppt에서는 유주자 형성이 급격히 감소하고 5 ppt에서는 유주자 발생이 이루어지지 않음이 확인되었다. 이러한 퍼킨서스편모충의 생태학적 정보는 이 질병의 구제 대책 수립에 중요한 정보를 제공할 수 있을 것으로 기대된다.

• 한국패류학회지
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• 제31권4호
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• pp.267-272
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• 2015

This study was conducted in order to elucidate the dissemination mechanism of P. olseni using field and laboratory experiments. For this purpose, we quantified the level of P. olseni infection in buried (healthy) and surfaced (gapped) R. philippinarum from a clam bed on Wi-do Island on the west coast of Korea. In addition, the levels of internal and released P. olseni cells from artificially infected (and later dead) R. philippinarum were monitored for 8 days using the RFTM-2 M NaOH lysis method. Our results indicate that P. olseni cells in buried R. philippinarum was $2,655,625{\pm}1,536,936cells/clam$; the level in gapped R. philippinarum was considerably lower, $28,203{\pm}24,889cells/clam$ (p < 0.05). In the laboratory experiment, the P. olseni cells remained in the host tissue 2 days after death was approximately 50% lower than the level of infection measured in living clams. The level dropped to 20% 4 days after death and to 1.5% 6 days after death; eight days after death, P. olseni cells were undetectable since the R. philippinarum flesh had completely decomposed. The level of released cells on the day of death was only 0.05% of the internal level in live R. philippinarum; however, the level increased to 2.3% 5 days after death then gradually decreased and no released cells were detected 8 days after death. Therefore, our laboratory experiment suggest that the low level of P. olseni infection observed in gapped R. philippinarum at Wi-do Island could be caused by lysis of the most of P. olseni cells during the decomposition of dead R. philippinarum tissues. Until the end of decomposition of R. philippinarum, 6.68% of the total amount of P. olseni was released within 8 days. Our study showed that the amount of P. olseni cells from dead host is a considerably higher level than naturally released from healthy R. philippinarum, suggesting that death of the host plays an important role in the dissemination of P. olseni.

• Ocean and Polar Research
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• 제43권4호
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• pp.365-370
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• 2021

Manila clam Ruditapes philippinarum is present at high rates of density in tidal flats in Cheonsu Bay on the west coast of Korea, where clams often exhibit mass mortalities in late summer. We monitored the pathologic condition of clams at Hwangdo tidal flat (HD) to understand the parasitic impacts on clam fitness. Manila clams were fully ripe in July and spawned during August and September, as the histology indicated. The histology revealed that clams in HD tidal flats were heavily infected by the protozoa parasite Perkinsus olseni, as the monthly prevalence ranged from 53% (September) to 93% (August). In addition, Manila clams were co-infected by the metazoan parasite Cercaria tapetis and Parvatrema duboisi with the prevalence of 0-33% and 0-14%, respectively. Massive hemocyte infiltration and subsequent inflammation were commonly observed from the gills of P. olseni infected clams. Clusters of P. olseni trophozoites and heavy hemocyte infiltration were also observed from the female gonad, suggesting that P. olseni interferes with host gonad maturation. The larval trematode occupied almost the entire host gonad, resulting in gonad castration. In addition, Metacercaria of P. duboisi were observed from the subsurface of the mantle. Ray's fluid thioglycollate medium assay (RFTM) indicated that clams collected in August and September contained approximately 4.0×106 P. olseni cells/g gills. Condition Index (CI) declined gradually from spring to early summer, and the decline in CI was interpreted as a consequence of the heavy parasitism, as the parasites drain the host's net energy to be used in somatic growth and gamete production.

• 한국양식학회:학술대회논문집
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• 한국양식학회 2006년도 수산관련학회 공동학술대회 발표요지집
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• pp.434-436
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• 2006

• Ocean and Polar Research
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• 제37권1호
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• pp.49-59
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• 2015

이 연구에서는 바지락의 성 성숙이 활발한 봄철에 경기만 선재도, 전북 곰소만, 및 남해 완도 등, 연중 수온 분포가 다른 지역에 분포하는 바지락 채집하여 P. olseni 감염이 번식에 미치는 영향을 조사하였다. 바지락의 산란은 연중 수온이 곰소나 선재도보다 높은 완도 바지락이 서해안 곰소 및 선재도 바지락보다 빠른 성 성숙 및 산란 활동을 보였다. P. olseni 감염이 바지락의 번식에 미치는 영향은 감염도가 다른 지역에 비해 세 배 이상 높은 완도에서 관찰되었으며, 완도 바지락은 여포 크기, 여포 내 성숙 난의 수 및 번식량 등이 타 지역보다 유의적으로 낮았다. 따라서 P. olseni 감염은 폐사 이외에도 다른 연구에서 밝혀진 바와 같이 번식 활동에 부정적인 영향을 미치는 것으로 확인되었다.

• 한국양식학회:학술대회논문집
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• 한국양식학회 2006년도 수산관련학회 공동학술대회 발표요지집
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• pp.430-431
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• 2006