Shimiella gen. nov. and Shimiella gracilenta sp. nov. (Dinophyceae, Kareniaceae), a Kleptoplastidic Dinoflagellate from Korean Waters and its Survival under Starvation.

A small dinoflagellate, ~13 µm in cell length, was isolated from Jinhae Bay, Korea. Light microscopy showed that it was similar to the kleptoplastidic dinoflagellate Gymnodinium gracilentum nom. inval. rDNA sequences were obtained and its anatomy and morphology described using light and scanning and transmission electron microscopy. Phylogenetic analyses indicated that it belonged to the family Kareniaceae. However, its large subunit (LSU) rDNA sequences were 5.2-9.5% different from those of the other five genera in the family, and its clade was clearly divergent from that of each genus. Its overall morphology was different from those of the other five genera in the family and from Gymnodinium. Unlike Gymnodinium, this dinoflagellate did not have a horseshoe-shaped apical groove, nuclear envelope chambers, or a nuclear fibrous connective (NFC). It had an apical line of narrow amphiesmal vesicles and an elongated apical furrow crossing the apex. Cells were covered with polygonal amphiesmal vesicles arranged in 16 rows. Starved cells did not contain their own plastids, eyespots, pyrenoids, peridinin, or fucoxanthin. However, they could survive without added prey for approximately one month using chloroplasts from the cryptophyte prey Teleaulax amphioxeia, indicating kleptoplastidy. Because this taxon is genetically distinct at the generic rank from the other genera in Kareniaceae, it is placed in Shimiella gen. nov., and because G. gracilentum was invalid, the new bionomial S. gracilenta sp. nov. is proposed.

Effects of light and temperature on the growth of Takayama helix (Dinophyceae): mixotrophy as a survival strategy against photoinhibition.

Takayama helix is a mixotrophic dinoflagellate that can feed on diverse algal prey. We explored the effects of light intensity and water temperature, two important physical factors, on its autotrophic and mixotrophic growth rates when fed on Alexandrium minutum CCMP1888. Both the autotrophic and mixotrophic growth rates and ingestion rates of T. helix on A. minutum were significantly affected by photon flux density. Positive growth rates of T. helix at 6-58 µmol photons · m-2  · s-1 were observed in both the autotrophic (maximum rate = 0.2 · d-1 ) and mixotrophic modes (0.4 · d-1 ). Of course, it did not grow both autotrophically and mixotrophically in complete darkness. At ≥247 µmol photons · m-2  · s-1 , the autotrophic growth rates were negative (i.e., photoinhibition), but mixotrophy turned these negative rates to positive. Both autotrophic and mixotrophic growth and ingestion rates were significantly affected by water temperature. Under both autotrophic and mixotrophic conditions, it grew at 15-28°C, but not at ≤10 or 30°C. Therefore, both light intensity and temperature are critical factors affecting the survival and growth of T. helix.

Gonyaulax whaseongensis sp. nov. (Gonyaulacales, Dinophyceae), a new phototrophic species from Korean coastal waters.

The planktonic phototrophic dinoflagellate Gonyaulax whaseongensis sp. nov., isolated from coastal waters of western Korea, was described from living and fixed cells under light and scanning electron microscopy, and its rDNA was sequenced. Gonyaulax whaseongensis had a plate formula of 2pr, 4', 6'', 6c, 6''', 1p, and 1'''' with S-type ventral organization like the other species in the genus. However, this dinoflagellate had a narrow cingulum (ca. 2.6 µm), small displacement of the cingulum, slight overhang and steep angle between the ends of the cingulum, quadrangular sixth precingular plate, reticulated cell surface without longitudinal lines or ridges, and two unequal antapical spines, together which distinguish this from all other reported Gonyaulax species. In addition, the SSU and LSU rDNA sequences were 8%-12% and 11%-24%, respectively, different from those of Gonyaulax polygramma, Gonyaulax spinifera, Gonyaulax fragilis, Gonyaulax membranacea, and Gonyaulax digitale, the putatively closest related species in the phylogenetic analysis.

Feeding by common heterotrophic protists on the mixotrophic alga Gymnodinium smaydae (Dinophyceae), one of the fastest growing dinoflagellates.

Gymnodinium smaydae is one of the fastest growing dinoflagellates. However, its population dynamics are affected by both growth and mortality due to predation. Thus, feeding by common heterotrophic dinoflagellates Gyrodinium dominans, Gyrodinium moestrupii, Oblea rotunda, Oxyrrhis marina, and Polykrikos kofoidii, and the naked ciliate Pelagostrobilidium sp. on G. smaydae was investigated in the laboratory. Furthermore, growth and ingestion rates of O. marina, G. dominans, and Pelagostrobilidium sp. on G. smaydae in response to prey concentration were also determined. Oxyrrhis marina, G. dominans, G. moestrupii, and Pelagostrobilidium sp. were able to feed on G. smaydae, but P. kofoidii and O. rotunda did not feed on this dinoflagellate. The maximum growth rate of O. marina on G. smaydae was 0.411 per day. However, G. smaydae did not support the positive growth of Pelagostrobilidium sp. The maximum ingestion rates of O. marina and Pelagostrobilidium sp. on G. smaydae were 0.27 and 6.91 ng C · predator-1  · d-1 , respectively. At the given mean prey concentrations, the highest growth and ingestion rates of G. dominans on G. smaydae were 0.114 per day and 0.04 ng C · predator-1  · d-1 , respectively. The maximum growth and ingestion rates of O. marina on G. smaydae are lower than those on most of the other algal prey species. Therefore, O. marina may be an effective predator of G. smaydae, but G. smaydae may not be the preferred prey for supporting high growth of the predator in comparison to other species as inferred from a literature survey.

Yihiella yeosuensis gen. et sp. nov. (suessiaceae, dinophyceae), a novel dinoflagellate isolated from the coastal waters of Korea.

A small (7-11 µm long) dinoflagellate with thin amphiesmal plates was isolated into culture from a water sample collected in coastal waters of Yeosu, southern Korea, and examined by LM, SEM, and TEM, and molecular analyses. The hemispheric episome was smaller than the hyposome. The nucleus was oval and situated from the central to the episomal region of the cell. A large yellowish-brown chloroplast was located at the end of the hyposome, and some small chloroplasts extended into the periphery of the episome. The dinoflagellate had a single elongated apical vesicle (EAV) and a type E eyespot, which are key characteristics of the family Suessiaceae. Unlike other genera in this family, it had two long furrow lines, one on the episome and the other on the hyposome, and encircling the dorsal, and lateral sides of the cell body. The pyrenoid lacked starch sheaths, but tubular invaginations into the pyrenoid matrix from the cytoplasm were observed. In the TEM, the dinoflagellate was observed to have cable-like structures (CLSs) near the eyespot but so far not observed in other dinoflagellates. The SSU rDNA sequences examined were 1.2%-5.1% different from those of other genera in the family Suessiaceae, whereas the LSU (D1-D3) rDNA sequences of this dinoflagellate were 15.1%-31.5% different. The dinoflagellate lacked a 51-bp fragment in domain D2 of the LSU rDNA, but it had an ~100-bp fragment in domain D2. This feature has been found previously only in the genera Leiocephalium and Polarella, two other genera of the Suessiaceae. The molecular phylogeny and sequence divergence based on SSU, and LSU rDNA indicate that the Korean dinoflagellate holds a taxonomically distinctive position and we consider it to be a new species in a new genus in the family Suessiaceae, named Yihiella yeosuensis gen. et sp. nov.

Most Low-Abundance "Background" Symbiodinium spp. Are Transitory and Have Minimal Functional Significance for Symbiotic Corals.

Speculation surrounds the importance of ecologically cryptic Symbiodinium spp. (dinoflagellates) that occur at low abundances in reef-building corals and in the surrounding environment. Evidence acquired from extensive sampling, long-term monitoring, and experimental manipulation can allow us to deduce the ecology and functional significance of these populations and whether they might contribute to the response of coral-dinoflagellate mutualisms to climate change. Quantitative PCR was used here to diagnose the prevalence, seasonal variation, and abundances of Symbiodinium spp. within and between colonies of the coral, Alveopora japonica. Consistent with broader geographic sampling, only one species comprised 99.9 %, or greater, the population of symbionts in every sample. However, other Symbiodinium including the non-mutualistic species, Symbiodinium voratum, were often detected, but at estimated cell densities thousands-fold less than the dominant symbiont. The temporal variation in prevalence and abundances of these "background" Symbiodinium could not be definitively related to any particular environmental factor including seasonality and water chemistry. The prevalence (proportion detected among host samples), but not abundance, of S. voratum may weakly correspond to increases in environmental inorganic silica (SiO2) and possibly nitrogen (NO3). When multiple background Symbiodinium occurred within an individual polyp, the average cell densities were positively correlated, suggesting non-specific processes of cell sorting and retention by the animal. While these findings substantiate the existence of a broader, yet uncharacterized, diversity of Symbiodinium, we conclude that only those species which can occur in high abundance and are temporally stable are ultimately important to coral-dinoflagellate mutualisms. Many transient Symbiodinium spp., which occur only at trace abundances in the coral's microbiome, belong to different functional guilds and likely have little, if any, importance to a coral's physiology. The successful integration between host and symbiont into a stable functional unit should therefore be considered when defining host-symbiont specificity.

Heterotrophic feeding as a newly identified survival strategy of the dinoflagellate Symbiodinium.

Survival of free-living and symbiotic dinoflagellates (Symbiodinium spp.) in coral reefs is critical to the maintenance of a healthy coral community. Most coral reefs exist in oligotrophic waters, and their survival strategy in such nutrient-depleted waters remains largely unknown. In this study, we found that two strains of Symbiodinium spp. cultured from the environment and acquired from the tissues of the coral Alveopora japonica had the ability to feed heterotrophically. Symbiodinium spp. fed on heterotrophic bacteria, cyanobacteria (Synechococcus spp.), and small microalgae in both nutrient-replete and nutrient-depleted conditions. Cultured free-living Symbiodinium spp. displayed no autotrophic growth under nitrogen-depleted conditions, but grew when provided with prey. Our results indicate that Symbiodinium spp.'s mixotrophic activity greatly increases their chance of survival and their population growth under nitrogen-depleted conditions, which tend to prevail in coral habitats. In particular, free-living Symbiodinium cells acquired considerable nitrogen from algal prey, comparable to or greater than the direct uptake of ammonium, nitrate, nitrite, or urea. In addition, free-living Symbiodinium spp. can be a sink for planktonic cyanobacteria (Synechococcus spp.) and remove substantial portions of Synechococcus populations from coral reef waters. Our discovery of Symbiodinium's feeding alters our conventional views of the survival strategies of photosynthetic Symbiodinium and corals.

Genetics and morphology characterize the dinoflagellate Symbiodinium voratum, n. sp., (Dinophyceae) as the sole representative of Symbiodinium Clade E.

Dinoflagellates in the genus Symbiodinium are ubiquitous in shallow marine habitats where they commonly exist in symbiosis with cnidarians. Attempts to culture them often retrieve isolates that may not be symbiotic, but instead exist as free-living species. In particular, cultures of Symbiodinium clade E obtained from temperate environments were recently shown to feed phagotrophically on bacteria and microalgae. Genetic, behavioral, and morphological evidence indicate that strains of clade E obtained from the northwestern, southwestern, and northeastern temperate Pacific Ocean as well as the Mediterranean Sea constitute a single species: Symbiodinium voratum n. sp. Chloroplast ribosomal 23S and mitochondrial cytochrome b nucleotide sequences were the same for all isolates. The D1/D2 domains of nuclear ribosomal DNA were identical among Western Pacific strains, but single nucleotide substitutions differentiated isolates from California (USA) and Spain. Phylogenetic analyses demonstrated that S. voratum is well-separated evolutionarily from other Symbiodinium spp. The motile, or mastigote, cells from different cultures were morphologically similar when observed using light, scanning, and transmission electron microscopy; and the first complete Kofoidian plate formula for a Symbiodinium sp. was characterized. As the largest of known Symbiodinium spp., the average coccoid cell diameters measured among cultured isolates ranged between 12.2 (± 0.2 SE) and 13.3 (± 0.2 SE) µm. Unique among species in the genus, a high proportion (approximately 10-20%) of cells remain motile in culture during the dark cycle. Although S. voratum occurs on surfaces of various substrates and is potentially common in the plankton of coastal areas, it may be incapable of forming stable mutualistic symbioses.

Gymnodinium smaydae n. sp., a new planktonic phototrophic dinoflagellate from the coastal waters of Western Korea: morphology and molecular characterization.

The marine phototrophic dinoflagellate Gymnodinium smaydae n. sp. is described from cells prepared for light, scanning, and transmission electron microscopy. Also, sequences of the small (SSU) and large subunits (LSU) and the internal transcribed spacer region (ITS1-5.8S-ITS2) of ribosomal DNA were analyzed. This newly isolated dinoflagellate possessed nuclear chambers, nuclear fibrous connective, an apical groove running in a counterclockwise direction around the apex, and a major accessory pigment peridinin, which are four key features for the genus Gymnodinium. The epicone was conical with a round apex, while the hypocone was ellipsoid. Cells growing photosynthetically were 6.3-10.9 µm long and 5.1-10.0 µm wide, and therefore smaller than any other Gymnodinium species so far reported except Gymnodinium nanum. Cells were covered with polygonal amphiesmal vesicles arranged in 11 horizontal rows, and the vesicles were smaller than those of the other Gymnodinium species. This dinoflagellate had a sharp and elongated ventral ridge reaching half way down the hypocone, unlike other Gymnodinium species. Moreover, displacement of the cingulum was 0.4-0.6 × cell length while in other known Gymnodinium species it is less than 0.3 × cell length. In addition, the new species possessed a peduncle, permanent chloroplasts, pyrenoids, trichocysts, pusule systems, and small knobs along the apical furrow, but it lacked an eyespot, nematocysts, and body scales. The sequence of the SSU, ITS1-5.8S-ITS2, and LSU rDNA region differed by 1.5-3.8%, 6.0-17.4%, and 9.1-17.5%, respectively, from those of the most closely related species. The phylogenetic trees demonstrated that the new species belonged to the Gymnodinium clade at the base of a clade consisting of Gymnodinium acidotum, Gymnodinium dorsalisulcum, Gymnodinium eucyaneum, etc. Based on morphological and molecular data, we suggest that the taxon represents a new species, Gymnodinium smaydae n. sp.

Food web structure for high carbon retention in marine plankton communities.

Total annual net primary productions in marine and terrestrial ecosystems are similar. However, a large portion of the newly produced marine phytoplankton biomass is converted to carbon dioxide because of predation. Which food web structure retains high carbon biomass in the plankton community in the global ocean? In 6954 individual samples or locations containing phytoplankton, unicellular protozooplankton, and multicellular metazooplankton in the global ocean, phytoplankton-dominated bottom-heavy pyramids held higher carbon biomass than protozooplankton-dominated middle-heavy diamonds or metazooplankton-dominated top-heavy inverted pyramids. Bottom-heavy pyramids predominated, but the high predation impact by protozooplankton on phytoplankton or the vertical migration of metazooplankton temporarily changed bottom-heavy pyramids to middle-heavy diamonds or top-heavy inverted pyramids but returned to bottom-heavy pyramids shortly. This finding has profound implications for carbon retention by plankton communities in the global ocean.

First report of the epiphytic benthic dinoflagellates Coolia canariensis and Coolia malayensis in the waters off Jeju Island, Korea: morphology and rDNA sequences.

Coolia spp. are epiphytic and benthic dinoflagellates. Herein, we report for the first time, the occurrence of Coolia canariensis and Coolia malayensis in Korean waters. The morphology of the Korean strains of C. canariensis and C. malayensis isolated from the waters off Jeju Island, Korea was similar to that of the original Canary lslands strains and Malaysian strains, respectively. We found several pores and a line of small knobs on the pore plate, and perforations within the large pores of both C. canariensis and C. malayensis. The plates of the Korean strains of C. canariensis and C. malayensis were arranged in a Kofoidian series of Po, 3', 7'', 6c, 6s, 5''', and 2'''', and Po, 3', 7'', 7c, 6-7s, 5''', and 2'''', respectively. When properly aligned, the large subunit (LSU) rDNA sequence of the Korean strain of C. canariensis was identical to that of the Biscayan strains, but it was 2-3% different from the Canary lslands strain VGO0775 and the Australian strain. In addition, the sequences of small subunit (SSU) and/or LSU rDNA from the two Korean strains of C. malayensis were < 1% different from the Malaysian strains of C. malayensis and the Florida strain CCMP1345 and New Zealand strain CAWD39 ("Coolia monotis"). In phylogenetic trees based on LSU rDNA sequences, the Korean strains of C. malayensis belonged to a clade including the Malaysian strains and these two strains. Therefore, based on genealogical analyses, we suggest that the Korean strain of C. canariensis is closely related to two Atlantic strains and the Australian strain, whereas the Korean strains of C. malayensis are related to the Malaysian strains of C. malayensis and the Florida and New Zealand strains.

First report of the epiphytic dinoflagellate Gambierdiscus caribaeus in the temperate waters off Jeju Island, Korea: morphology and molecular characterization.

Gambierdiscus spp. are epiphytic, benthic dinoflagellates. Some species have been shown to be toxic and cause ciguatera fish poisoning. We report, for the first time, the occurrence of Gambierdiscus caribaeus isolated from the waters off Jeju Island in Korea. Its morphology was similar to that of the original Belize strains of G. caribaeus. Gambierdiscus caribaeus has been reported in the tropical and subtropical waters of the Pacific, Gulf of Mexico, Caribbean Sea, and Floridian coast. Our report extends its range to the North Pacific Ocean. The plates of the Korean strain were arranged in a Kofoidian series of Po, 3', 7'', 6c, 6s, 5''', 1p, and 2'''', morphologically closer to other strains of G. caribaeus than to G. carpenteri. When properly aligned, its small subunit (SSU) rDNA was 0.5% different from those of Gambierdiscus sp. C-1, a strain that was isolated from the waters off eastern Japan, but was 2.4-4.0% different from those of the NOAA strains of G. caribaeus and 3.1-3.4% different from those of the NOAA strains of G. carpenteri. Additionally, the D1-D3 large subunit (LSU) rDNA sequence of the Korean strain of G. caribaeus was 4.7-5.3% different from those of the NOAA strains of G. caribaeus and 7.1-7.5% different from those of all reported G. carpenteri strains, including the NOAA strains. In phylogenetic trees based on SSU and LSU rDNA sequences, our Korean strain was basal to the clade consisting of the NOAA strains of G. caribaeus, which in turn was sister clade to all reported G. carpenteri strains.

Feeding diverse prey as an excellent strategy of mixotrophic dinoflagellates for global dominance.

Microalgae fuel food webs and biogeochemical cycles of key elements in the ocean. What determines microalgal dominance in the ocean is a long-standing question. Red tide distribution data (spanning 1990 to 2019) show that mixotrophic dinoflagellates, capable of photosynthesis and predation together, were responsible for ~40% of the species forming red tides globally. Counterintuitively, the species with low or moderate growth rates but diverse prey including diatoms caused red tides globally. The ability of these dinoflagellates to trade off growth for prey diversity is another genetic factor critical to formation of red tides across diverse ocean conditions. This finding has profound implications for explaining the global dominance of particular microalgae, their key eco-evolutionary strategy, and prediction of harmful red tide outbreaks.

Survival after in-hospital cardiopulmonary resuscitation from 2003 to 2013: An observational study before legislation on the life-sustaining treatment decision-making act of Korean patients.

We analyzed cardiopulmonary resuscitation (CPR) rates, deaths preceded by CPR, and survival trends after in-hospital CPR, using a sample of nationwide Korean claims data for the period 2003 to 2013.The Korean National Health Insurance Service-National Sample Cohort is a stratified random sample of 1,025,340 subjects selected from among approximately 46 million Koreans. We evaluated the annual incidence of CPR per 1000 admissions in various age groups, hospital deaths preceded by CPR, and survival rate following in-hospital CPR. Analyses of the relationships between survival and patient and hospital characteristics were performed using logistic regression analysis.A total of 5918 in-hospital CPR cases from 2003 to 2013 were identified among eligible patients. The cumulative incidence of in-hospital CPR was 3.71 events per 1000 admissions (95% confidence interval 3.62-3.80). The CPR rate per 1000 admissions was highest among the oldest age group, and the rate decreased throughout the study period in all groups except the youngest age group. Hospital deaths were preceded by in-hospital CPR in 18.1% of cases, and the rate decreased in the oldest age group. The survival-to-discharge rate in all study subjects was 11.7% during study period, while the 6-month and 1-year survival rates were 8.0% and 7.2%, respectively. Survival tended to increase throughout the study period; however, this was not the case in the oldest age group. Age and malignancy were associated with lower survival rates, whereas myocardial infarction and diabetes mellitus were associated with higher survival rates.Our result shows that hospital deaths were preceded by in-hospital CPR in 18.1% of case, and the survival-to-discharge rate in all study subjects was 11.7% during the study period. Survival tended to increase throughout the study period except for the oldest age group. Our results provide reliable data that can be used to inform judicious decisions on the implementation of CPR, with the ultimate goal of optimizing survival rates and resource utilization.

Survival rates following medical intensive care unit admission from 2003 to 2013: An observational study based on a representative population-based sample cohort of Korean patients.

The decision as to whether patients should be admitted to a medical intensive care unit (ICU), in the absence of information concerning survival rates or prognostic factors in survival, is often challenging. We analyzed survival trends in relation to hospital discharge and examined patient and hospital characteristics associated with survival following ICU care, using a sample of nationwide claims data in Korea from 2002 through 2013. The Korean government implements a compulsory social insurance program that covers the country's entire population, and the Korean National Health Insurance Service-National Sample Cohort (NHIS-NSC) data from 2002 based on this program were used for this study. The NHIS-NSC is a stratified random sample of 1,025,340 subjects selected from around 46 million Koreans. We evaluated annual survival trends using the Kaplan-Meier test. Analyses of the relationship between survival and patient and hospital characteristics were performed using Cox regression analyses. Employing a multivariate model, variables were selected using the forward selection method to consider the multicollinearity of variables. A total of 32,553 patients admitted to an ICU between 2002 and 2013 were identified among the eligible beneficiaries. The number of patients who had histories of ICU admission steadily increased throughout the study period, and patients older than 80 years constituted a progressively increasing proportion of ICU admissions, from 7.3% in 2002 to 16.9% in 2007 to 23.1% in 2013. The mean number of mechanical equipment items applied consistently increased, while no difference was observed in the trend for overall 1-year survival in patients following ICU treatment across the study period: the 1-year survival rate ranged from 66.7% (year 2003) to 64.2% (year 2010). Advanced age, cancer, renal failure, pneumonia, and influenza were all associated with heightened risk of mortality within 1 year. Our results should prove useful to older patients and their clinicians in their decisions regarding whether to seek ICU care, with the goals of improving the end-of life care and optimizing resource utilization.

Effects of warming and eutrophication on coastal phytoplankton production.

Phytoplankton production in coastal waters influences seafood production and human health and can lead to harmful algal blooms. Water temperature and eutrophication are critical factors affecting phytoplankton production, although the combined effects of warming and nutrient changes on phytoplankton production in coastal waters are not well understood. To address this, phytoplankton production changes in natural waters were investigated using samples collected over eight months, and under 64 different initial conditions, established by combining four different water temperatures (i.e., ambient T, +2, +4, and + 6 °C), and two different nutrient conditions (i.e., non-enriched and enriched). Under the non-enriched conditions, the effect of warming on phytoplankton production was significantly positive in some months, significantly negative in others, or had no effect. However, under enriched conditions, warming affected phytoplankton production positively in all months except one, when the salinity was as low as 6.5. These results suggest that nutrient conditions can alter the effects of warming on phytoplankton production. Of several parameters, the ratio of initial nitrate concentration to chlorophyll a concentration [NCCA, µM (µg L-1)-1] was one of the most critical factors determining the directionality of the warming effects. In laboratory experiments, when NCCA in the ambient or nutrient-enriched waters was ≥1.2, warming increased or did not change phytoplankton production with one exception; however, when NCCA was <1.2, warming did not change or decreased production. In the time series data obtained from the coastal waters of four target countries, when NCCA was 1.5 or more, warming increased phytoplankton production, whereas when NCCA was lower than 1.5, warming lowered phytoplankton production, Thus, it is suggested that NCCA could be used as an index for predicting future phytoplankton production changes in coastal waters.

Feeding by the heterotrophic nanoflagellate Katablepharis remigera on algal prey and its nationwide distribution in Korea.

Heterotrophic nanoflagellates are ubiquitous in natural waters, and most heterotrophic nanoflagellates are known to grow on bacteria. Recently, the heterotrophic nanoflagellate Katablepharis japonica has been reported to be an effective predator of diverse toxic or harmful algal prey. To date, 7 Katablepharis species have been identified, and therefore important questions arise as to whether other Katablepharis species can feed on algal prey, and further whether the types of prey of other Katablepharis species differ from those of K. japonica. To answer these important questions, feeding by Katablepharis remigera on diverse algal prey was examined. Specific growth and ingestion rates of K. remigera feeding on the raphidophytes Heterosigma akashiwo and Chattonella subsalsa were determined. Furthermore, the abundance of K. remigera at 28 stations along the coastline of Korea from January 2015 to October 2017 was quantified using qPCR method and newly designed specific primer-probe sets. Among 25 potential algal prey tested, K. remigera fed on only H. akashiwo and C. subsalsa; however, it did not feed on a diatom, a prymnesiophyte, a prasinophyte, cryptophytes, dinoflagellates, Mesodinium rubrum, a mixotrophic ciliate, and another raphidophyte Fibrocapsa japonica. The number of prey types on which K. remigera could feed (2 species) was considerably smaller than that of K. japonica (14 species). With the increase in the mean prey concentration, the specific growth rates of K. remigera on H. akashiwo and C. subsalsa increased as well before becoming saturated. The maximum specific growth rates of K. remigera on H. akashiwo and C. subsalsa were 0.717 and 0.129 d-1, respectively. In addition, the maximum ingestion rates of K. remigera on H. akashiwo and C. subsalsa were 0.333 and 0.661 ng C predator-1 d-1 (3.33 and 0.23 cells predator-1 d-1), respectively. The results of this study clearly indicate that K. remigera is an effective predator of 2 red tide-causing raphidophyte species, and additionally, the feeding activity of K. remigera differs greatly from that of K. japonica. The abundance of K. remigera was ≥0.1 cells mL-1 at 24 stations located in the East, West, and South Sea of Korea. Thus, K. remigera has a nationwide distribution in Korea. The highest abundance of K. remigera in Korean waters was 24.9 cells mL-1 in March 2017, when there was no red tide caused by H. akashiwo or Chattonella spp. In most regions where red tides caused by H. akashiwo or Chattonella spp. occurred in 2000-2017, K. remigera was detected. Thus, the abundance of K. remigera may increase during red tides caused by H. akashiwo and Chattonella spp.

Control of ichthyotoxic Cochlodinium polykrikoides using the mixotrophic dinoflagellate Alexandrium pohangense: A potential effective sustainable method.

Red tides dominated by Cochlodinium polykrikoides often lead to great economic losses and some methods of controlling these red tides have been developed. However, due to possible adverse effects and the short persistence of their control actions, safer and more effective sustainable methods should be developed. The non-toxic dinoflagellate Alexandrium pohangense is known to grow well mixotrophically feeding on C. polykrikoides, and populations are also maintained by photosynthesis. Thus, compared with other methods, the use of mass-cultured A. pohangense is safer and the effects can be maintained in the long term. To develop an effective method, the concentrations of A. pohangense cells and culture filtrate resulting in the death of C. polykrikoides cells were determined by adding the cells or filtrates to cultured and natural populations of C. polykrikoides. Cultures containing 800 A. pohangense cells ml-1 eliminated almost all cultured C. polykrikoides cells at a concentration of 1000 cells ml-1 within 24h. Furthermore, the addition of A. pohangense cultures at a concentration of 800 cells ml-1 to C. polykrikoides populations from a red-tide patch resulted in the death of most C. polykrikoides cells (99.8%) within 24h. This addition of A. pohangense cells also lowered the abundances of total phototrophic dinoflagellates excluding C. polykrikoides, but did not lower the abundance of total diatoms. Filtrate from 800cellsml-1A. pohangense cultures reduced the population of cultured C. polykrikoides by 80% within 48h. This suggests that A. pohangense cells eliminate C. polykrikoides by feeding and releasing extracellular compounds. Over time, A. pohangense concentrations gradually increased when incubated with C. polykrikoides. Thus, an increase in the concentration of A. pohangense by feeding may lead to A. pohangense cells eliminating more C. polykrikoides cells in larger volumes. Based on the results of this study, a 1m3 stock culture of A. pohangense at 4000cellsml-1 is calculated to remove all C. polykrikoides cells in ca. 200m3 within 6 days. Furthermore, maintenance of A. pohangense populations through photosynthesis prepared A. pohangense to eliminate C. polykrikoides cells in future red-tide patches. Moreover, incubation of A. pohangense at 2000 cells ml-1 with juvenile olive flounder Paralichthys olivaceus for 3 days did not result in the death of fish. Therefore, the method developed in this study is a safe and effective way of controlling C. polykrikoides populations and can be easily applied to aqua-tanks on land.

De novo assembly and characterization of the transcriptome of the newly described dinoflagellate Ansanella granifera: Spotlight on flagellum-associated genes.

Many dinoflagellates are known to cause red tides and often outgrow non-motile diatoms and motile small flagellates through active vertical migration between well-lit surface and eutrophic deep waters and/or by locating and ingesting prey cells. Their flagella play important roles in these two critical behaviors. However, the structural and functional genes of dinoflagellate flagella are very little known. Thus, a de novo assembly and characterization of the transcriptome of the fast-swimming dinoflagellate Ansanella granifera were conducted and its flagellum genes were compared with those of other dinoflagellates, motile small flagellates, and non-motile protist species. Based on assembled data using Trinity/CLC combined strategy, 83,652 transcripts of A. granifera were identified. The assembled consensus sequences were annotated to the NCBI non-redundant (nr), InterProScan, Gene Ontology (GO), and KEGG pathway analyses. Moreover, 71 structural and 35 functional flagellum-associated genes expressed were identified. The number of expressed flagellar structural and functional genes of A. granifera was not markedly different from those of other dinoflagellates or motile small flagellates, but much greater than those of non-motile species. Furthermore, in both phylogenetic trees based on the outer dynein arm (ODA1, ODA9, and DLC1) and inner dynein arm (IDA4, IDA7, and BOP5) flagellum genes of dinoflagellates, the problem of the long-branch attraction artifacts of Oxyrrhis marina which has been reported in the phylogenetic trees based on ribosomal DNA was removed. Moreover, in both phylogenetic trees based on the ODA and IDA flagellum genes, the species in the order Peridiniales or Gymnodiniales were revealed to belong to a big clade of each order. Therefore, the phylogenetic tree based on the flagellum genes is likely to give a clue to resolve the problem of separation in a big clade of a dinoflagellate order which has also been reported in the phylogenetic trees based on ribosomal DNA.

Contribution of subjective Disease Activity Score 28 (DAS28) components to the response to treatment of rheumatoid arthritis.

We investigated the contributions made by the subjective components of the Disease Activity Score 28 (DAS28) to the treatment response of rheumatoid arthritis (RA). In addition, factors associated with poor response to treatment at 6 months, despite normalization of objective measures, were examined. A total of 426 newly diagnosed RA patients were included. The DAS28-P score (the subjective components of the DAS28 relative to the total components) was calculated as DAS28-P = 0.56 ∗ sqrt(TJC28) + 0.014 ∗ (VAS-GH) /0.56 ∗ sqrt(TJC28) + 0.28 ∗ sqrt(SJC28) + 0.7 ∗ In(erythrocyte sedimentation rate (ESR)) + 0.014 ∗ (VAS-GH). The European League Against Rheumatism (EULAR) response was assessed after 6 months of treatment. Of those who failed to attain good EULAR responses, those for whom the objective measures (the ESR, the C-reactive protein level, and swollen joints) were normalized were defined as having failed treatment because of subjective measures. The median (IQR) DAS28 score at baseline was 4.8 (4.04-5.49) and that after 6 months of treatment 3.21 (2.41-3.95). The DAS28-P score fell significantly from baseline to 6 months in good (0.43 versus 0.28, p < 0.001) and moderate responders (0.44 versus 0.4, p = 0.003), but not in non-responders (0.43 versus 0.45, p = 0.727). Younger age, a lower DAS28 score, and a lower DAS28-P score at baseline were related to a good EULAR response. Subjects who failed to respond because of subjective measures tended to have higher DAS28-P scores at baseline. We found that RA patients with high DAS28-P scores, reflecting subjective measures, were less likely to achieve good EULAR responses 6 months after treatment initiation and tended not to be classified as good responders despite normalization of objective measures.