• Animal cells and systems
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• v.5 no.4
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• pp.291-297
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• 2001

Three species of endosymbiotic dinoflagellates, zooxanthellae, are investigated from six host species of anthozoans from Korea. Three unrecorded endosymbionts species are Symbiodinium kawagutii, Symbiodinium microadriaticum, and Symbiodinium sp. Symbiodinium kawagutii Is associated with Alveopora japonica, Anthopleura japonica and Parasicyonis actinostoloides. Symbiodinium microadiraticum is found in Anthopleura kurogane and Parasicyonis sp. Unlike the former two symbionts, Symbiodinium sp. is associated with Anthopleura midori.

• Animal cells and systems
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• v.15 no.4
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• pp.315-324
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• 2011

The actiniarian sea anemone, Entacmaea quadricolor, and the scleractinian coral, Alveopora japonica, host symbiotic dinoflagellates belonging to the genus Symbiodinium (Freudenthal). We studied the host-symbiont specificity of these two anthozoan hosts in the northwestern Pacific Ocean. Symbionts within the two hosts were identified using partial large subunit (LSU) ribosomal DNA (rDNA) and complete internal transcribed spacers (ITS) 1 rDNA regions. The host, E. quadricolor, was identified using the partial LSU rDNA molecular marker. Genetic analysis showed that E. quadricolor only harbors dinoflagellates belonging to subclade C1/3 of the genus Symbiodinium. Moreover, no genetic variation was detected among the symbionts of E. quadricolor within the study region (Korea and Japan), even though the two distant sites were separated by more than 1000 km, at collection depths of 1 m in shallow and 13-16 m in deep water. Whilst scleractinian corals host multiple Symbiodinium clades in tropical waters, A. japonica, sampled over a wide geographical range (800 km) within the study region, only hosts Symbiodinium sp. clade F3. The high specificity of endosymbionts in E. quadricolor and A. japonica within the northwestern Pacific Ocean could be accounted for because symbiotic dinoflagellates within the host anemones appear to be acquired maternally, and the Kuroshio Current might affect the marine biota of the northwestern Pacific. However, the consistency of the symbiotic relationships between these two anthozoan hosts and their endosymbionts could change after climate change, so this symbiotic specificity should be monitored.

• Proceedings of the Zoological Society Korea Conference
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• 2001.10a
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• pp.127.2-127
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• 2001

No Abstract, See Full Text

• Proceedings of the Zoological Society Korea Conference
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• 2003.08a
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• pp.126.4-126
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• 2003

No Abstract, See Full Text

• Journal of Food Hygiene and Safety
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• v.10 no.2
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• pp.73-79
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• 1995

Incidents of seafood and massive fish kills have been rapidly increasing in both frequency and geographical distribution and the socioeconomic impacts brought by those incidents. However, the biological origins of those marine toxins have not been well clarified. Most of the marine organisms investigated are filter-feeder, which accumulate toxins from their food and/or their symbiotic microalgae. We have examined the action on rabbit platelets of marine toxins isolated from cultured dinoflagellates and sponge collected at Okinawa. Maitotoxin (MTX) is a water-soluble toxin isolated from the cultured dinoflagellate Gambierdiscus toxicus which causes a seafood poisoning in tropical regions. Zooxanthellatoxin A (ZT-A) was isolated from exteracts of cultured symbiotic dinoflagellate Symbiodinium sp. (socalled zooxanthella) from flatworms of the genus Amphiscolops collected at Okinawan marine sponge Theonella sp. MTX caused a disaggregation and a dissolution of large aggregates. ZT-A caused a dissolution of small aggregates followed by a increment of light tranmission. TZ-A caused an initial and transient shape change followed by a sustained aggregation and a increment of large aggregates. In conclusion, marine toxins exert unique patterns on the light trasmission and the size of aggregates in rabbit platelets by their concentrations and kinds

• ALGAE
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• v.29 no.4
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• pp.299-310
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• 2014

Dinoflagellates in the genus Symbiodinium are known as zooxanthellae and exist as either symbiotic or free-living forms. Among this genus, two species, Symbiodinium minutum and Symbiodinium psygmophilum, were recently established based on genetic characters. However, some critical morphological characters of these species, such as plate formulae and related diagnoses have not been provided yet. In this study, we analyzed the morphology of S. minutum and S. psygmophilum by scanning and transmission electron microscopy. The S. minutum had the Kofoidian plate formula consisting of a small plate (x), elongated amphiesmal vesicle (EAV), 4', 5a, 8", 7s, two cingulum rows, 18-20c, 6''', and 2'''', while S. psygmophilum had x, EAV, 4', 5a, 8", 7-10s, two cingulum rows, 20-22c, 5-6''', and 1''''. These plate formulae are different from any other reported Symbiodinium species. In addition, both species had a pentagonal 1a plate and a hexagonal 2a plate, while other known Symbiodinium species had a hexagonal 1a plate and a pentagonal 2a plate. Thus, we confirm the species status of S. minutum and S. psygmophilum based on morphological and genetic characters and report the detailed morphological characteristics of these two species.