• Journal of the korean society of oceanography
• /
• v.37 no.2
• /
• pp.58-65
• /
• 2002

The study of microbial communities in sediments is impaired by the lack of reliable extraction methods. This study reports on the efficiency of recovery of a method for extracting bacteria, protists and diatoms from sandy sediments using a modified decant/fix method. The best extractions were achieved after fixation with a microtubule stabilising fixative and subsequent sonication for 80 seconds. We estimate that the efficiencies of recovery of bacteria and mixed heterotrophic flagellates were $96.4{\pm}3.5\%$ and $96.9{\pm}4.6\%$, respectively. Diatoms were recovered with an efficiency of 38-83% and varied considerably from species to species. This study suggests that the decant/fix method is effective in extracting small cells such as bacteria and heterotrophic flagellates, and that the efficiency of recovery of the method varies due to cell length and different types of organisms. When microbial carbon biomass had been underestimated by up to 32%, with much of that relating to larger cells such as microalgae and ciliates. We note that the corrected abundances may be still a subset of the total numbers present.

• Animal Systematics, Evolution and Diversity
• /
• v.27 no.2
• /
• pp.115-122
• /
• 2011

The morphology of the two marine hypotrichous ciliates Apokeronopsis bergeri and A. ovalis, isolated from the Yellow Sea, Korea, are described based on live and protargol-impregnated specimens. It is the first time that these species have been recorded in Korea. In addition, the small subunit ribosomal RNA gene was sequenced for comparison with the public database. The genus Apokeronopsis has recently been established in the family Pseudokeronopsidae, and the two congeners of the Korean population share the following characteristics: one row of one or more buccal cirri; usually two frontoterminal cirri; midventral complex composed of two distinctly separated rows; one left and one right marginal row; number of transverse cirri, more than eight; absence of caudal cirri; two types of cortical granules. Apokeronopsis bergeri differs from A. ovalis primarily in body shape (fusiform vs. oval form), size (usually $260{\times}80{\mu}m$ vs. $160{\times}55{\mu}m$), type II cortical granules (oval vs. round shape; yellow-green vs. mostly colourless and only a few yellow-green in colour), and morphometric data (75-106 vs. 53-70 in adoral membranelles; 37-47 vs. 24-36 in frontal cirri; 9-15 vs. 1-2 in buccal cirri), as well as molecular data (2.87% of pairwise distance).

• Ocean and Polar Research
• /
• v.31 no.1
• /
• pp.77-95
• /
• 2009

Ciliate abundance and biomass were determined at three anchored stations in the Han River estuary trimonthly from May 2006 to February 2008. The total abundance of ciliates ranged from 0-13,853 cells $l^{-1}$ and biomass ranged from $0.00-73.98\;ugC\;l^{-1}$. Owing to the large seasonal temperature variation (range 0.20-$27.2^{\circ}C$), ciliate abundance displayed marked seasonal variation, being higher in summer than in other seasons. Tintinnids dominated the ciliate communities at station YC where suspended sediment was highest. Difference of ciliate biomass between ebb tide and flood tide were irregular. Seasonal variations of ciliate carbon biomass at each station were related to temperature, suspended sediment and chl.a, especially nano chl.a. Geographical variations of ciliate carbon biomass in each season were related to suspended sediment and salinity.

• Journal of Species Research
• /
• v.1 no.1
• /
• pp.78-86
• /
• 2012

Three ciliate species of genus Cyrtohymena, C. australis Foissner, 1995, C. citrina (Berger & Foissner, 1987) and C. muscorum (Kahl, 1932) new to Korea, were collected from semi-terrestrial habitats. The description was based on the observation of live and silver stained specimens. Diagnostic characteristics of these species are as follows. C. autralis: size about $275{\times}100{\mu}m$ in live specimens. Cortical granules yellowish. 18-31 right and 31-40 left marginal cirri in number. Dorsal kineties eight rows. C. citrina: size about $180{\times}50{\mu}m$ in live specimens. Cortical granules yellowish. 26-32 right and 23-27 left marginal cirri in number. Dorsal kineties five to six rows. C. muscorum: size about $180{\times}60{\mu}m$ in live specimens. Cortical granules reddish. 31-34 right and 33-36 left marginal cirri in number. Dorsal kineties six rows. Three species of Cyrtohymena have been added to Korean ciliate fauna from this study. Including previous one species of C. quadrinucleata, four species of this genus in total have been recorded so far in this country.

• Animal Systematics, Evolution and Diversity
• /
• v.31 no.4
• /
• pp.277-283
• /
• 2015

Two pleurostomatid ciliates, Loxophyllum perihoplophorum Buddenbrock, 1920 and L. rostratum Cohn, 1866, were collected from the coastal waters of the East Sea, Korea. Their morphologies are described based on live observation and protargol staining, and morphometrics are provided. Loxophyllum perihoplophorum is characterized by the following features: 200-650 μm long in vivo; body slender leaf-shaped, flexible and contractile, with thin and wide extrusome-belted zone; 2 macronuclear nodules (Ma) and 1 micronucleus (Mi); 7-9 contractile vacuoles (CV) positioned along dorsal margin; extrusomes (Ex) evenly distributed along edge of entire body, with about 10 dorsal warts (Wa); 9-11 left (LSK) and 19-22 right somatic kineties (RSK), 4-5 furrows (Fu) on left side. Loxophyllum rostratum is about 100-130 μm long in vivo; body oblate leaf-shaped, contractile, convex ventral side and S-shaped dorsal side, beak-like anterior end; 2 Ma and 1 Mi; 1 CV terminally located; Ex distributed along edge of entire body, with about 9-10 dorsal Wa; 7-8 LSK and 15-19 RSK, ca. 5 Fu on left body side. In addition, sequences of small subunit ribosomal DNA were determined from these two Loxophyllum species and compared with the known Loxophyllum sequences.

• Journal of fish pathology
• /
• v.21 no.3
• /
• pp.167-174
• /
• 2008

Few studies on parasitic scutica-like ciliates (SLCs) influencing larval growth and survival during the seed production of the Japanese scallop, Patinopecten yessoensis have been performed in spite of relatively high magnitude of their infectious damage to the larvae. In the mass seed production of the scallop, SLCs were never infectious during D-larval stage which lasted 6 to 7 days. Indeed, the infection first occurred in 2 to 4 days after first umbo-staged larvae. A regular selection of active larvae in swimming behavior kept larval SLC infection low throughout the culture compared to unselected control (P<0.05) in which all the larvae alive were contained. Higher infection frequencies of the unselected control resulted in lower larval survivals and wider range of larval size distribution that drove larval attachment rate lower. To the worse, the nursery spats from the higher SLC infection exhibited a retarded growth and elevated occurrence of abnormal scallop.

• Journal of Species Research
• /
• v.9 no.4
• /
• pp.427-442
• /
• 2020

We collected indigenous Korean ciliate species from diverse aquatic and terrestrial habitats in 2018 and 2019. The morphology of these ciliates was revealed based on the observations of living cells, and protargol-impregnated and/or silver carbonate-impregnated specimens. During this study, we found 16 previously unrecorded Korean ciliate species, which are as follows: 1) class Heterotrichea - Stentor introversus; 2) class Spirotrichea - Aspidisca orthopogon, Amphisiella sinica, Epiclintes auricularis rarisetus, Apokeronopsis wrighti, Pseudokeronopsis carnea, Trachelostyla pediculiformis, Strombidium apolatum, and Varistrombidium kielum; 3) class Phyllopharyngea - Chlamydodon obliquus, Dysteria aculeata, and Hartmannula angustipilosa; 4) class Litostomatea - Paraspathidium apofuscum; and 5) class Oligohymenophorea - Frontonia angusta solea, Metanophrys sinensis, and Uronemita binucleata. Here, we provide a diagnosis for each species with a brief remark. Among them, the infraciliature of the poorly known species, Stentor introversus and Dysteria aculeata, is described for the first time. Further, we revise the Korean population of Pseudokeronopsis pararubra, which was previously misidentified as Pseudokeronopsis carnea.

• Journal of Species Research
• /
• v.11 no.4
• /
• pp.278-286
• /
• 2022

During a field survey of Korean marine ciliates, we collected Pleuronema marinum from a brackish water sample. It is characterized by the presence of a contractile vacuole in mid-body, rather than the subterminal/ terminal contractile vacuole as in other congeners. The cells were examined in vivo and based on protargol and 'wet' silver nitrate impregnation. In addition, the nuclear 18S rRNA gene was sequenced using a single cell. The Korean population morphologically and molecularly resembles a Chinese population of P. marinum. Historical review of the species concludes that 1) two or more species have been assigned into P. marinum, 2) the position of contractile vacuole (e.g., in mid-body) is a valid character state, and 3) P. marinum is probably a rare species. Here we provide a monographic treatment of P. marinum to clarify the issue and for further studies of relevant species. Considering there are about 40 nominal species and complex nomenclatural acts in the genus Pleuronema, further studies should provide descriptions based on protargol and 'wet' silver impregnation with marker gene(s).

• Journal of Species Research
• /
• v.12 no.3
• /
• pp.203-211
• /
• 2023

Five ciliate species of Euplotes were isolated from fresh and coastal water during a sampling survey to identify unrecorded ciliates in South Korea. Their morphology was investigated using live observation, protargol and "wet" silver nitrate staining methods. Brief descriptions and microphotographs of each species and a comparison with related species are provided. Euplotes focardii is characterized by an average size of 65×47 ㎛ after protargol impregnation, 6 dorsal and 3 ventral ridges and dorsal argyrome pattern of double-eurystomus type. Euplotes nobilii shows an average size of 34×20 ㎛ after protargol staining, 6 dorsal and 3 ventral ridges and dorsal argyrome pattern of double-patella type. Euplotes octocarinatus, the only freshwater species described in the present study, is characterized by an average size of 66×46 ㎛ after protargol impregnation, 6 dorsal and 3 ventral ridges and dorsal argyrome pattern of double-patella type. Euplotes petzi has an average size of 43×30 ㎛ after protargol staining, a macronucleus hook-shaped and dorsal argyrome pattern in double-patella type. Euplotes raikovi is characterized by an average size of 40×24 ㎛ after protargol staining, 6 dorsal and 3 ventral ridges and dorsal argyrome pattern of double-patella type.

• Korean Journal of Environmental Biology
• /
• v.33 no.4
• /
• pp.403-411
• /
• 2015

To understand differences of environmental factors and planktonic communities in closed (CS) versus open (OS) enclosed experimental systems, we performed a study on a 100-L indoor-type artificial marine microcosm. For environmental factors, including water temperature, dissolved inorganic phosphorus, and dissolved silica, there were no significant differences between CS and OS; however, salinity was higher in CS than that of OS due to the evaporation effect. The concentration of dissolved oxygen and dissolved inorganic nitrogen was lower in CS than in OS. The abundance of phytoplankton was lower in CS than in OS. However, abundance of autotrophic nanoflagellates and heterotrophic bacteria varied inversely with that of phytoplankton abundances. In particular, the abundance of heterotrophic nanoflagellates and ciliates increased with bacterial growth after a time lag. Therefore, environmental factors and planktonic communities in CS gradually changed over time and characterized a different artificial ecosystem than in OS.