Determination of the Absolute Configuration of Polyhydroxy Compound Ostreol B Isolated from the Dinoflagellate Ostreopsis cf. ovata.

Following isolation of the polyhydroxy compound, ostreol B, from cultivated cells of the toxic dinoflagellate Ostreopsis cf. ovata collected in South Korea, 1D and 2D NMR spectroscopy were employed to determine the planar chemical structure of this compound, which contained a tetrahydropyran ring, two terminal double bonds, and 21 hydroxyl groups. The absolute configurations of all stereogenic carbon centers in ostreol B were then determined through a combination of the J-based configuration analysis, rotating frame Overhauser effect correlations, and the modified Mosher method following cleavage of the 1,2-diol bonds. Ostreol B was also found to exhibit moderate cytotoxicity in HepG2, Neuro-2a and HCT-116 cells.

Characterization of a New Trioxilin and a Sulfoquinovosyl Diacylglycerol with Anti-Inflammatory Properties from the Dinoflagellate Oxyrrhis marina.

Two new compounds-a trioxilin and a sulfoquinovosyl diacylglycerol (SQDG)-were isolated from the methanolic extract of the heterotrophic dinoflagellate Oxyrrhis marina cultivated by feeding on dried yeasts. The trioxilin was identified as (4Z,8E,13Z,16Z,19Z) -7(S),10(S),11(S)-trihydroxydocosapentaenoic acid (1), and the SQDG was identified as (2S)-1-O-hexadecanosy-2-O-docosahexaenoyl-3-O-(6-sulfo-α-d-quinovopyranosyl)-glycerol (2) by a combination of nuclear magnetic resonance (NMR) spectra, mass analyses, and chemical reactions. The two compounds were associated with docosahexaenoic acid, which is a major component of O. marina. The two isolated compounds showed significant nitric oxide inhibitory activity on lipopolysaccharide-induced RAW264.7 cells. Compound 2 showed no cytotoxicity against hepatocarcinoma (HepG2), neuroblastoma (Neuro-2a), and colon cancer (HCT-116) cells, while weak cytotoxicity was observed for compound 1 against Neuro-2a cells.

The newly described heterotrophic dinoflagellate Gyrodinium moestrupii, an effective protistan grazer of toxic dinoflagellates.

Few protistan grazers feed on toxic dinoflagellates, and low grazing pressure on toxic dinoflagellates allows these dinoflagellates to form red-tide patches. We explored the feeding ecology of the newly described heterotrophic dinoflagellate Gyrodinium moestrupii when it fed on toxic strains of Alexandrium minutum, Alexandrium tamarense, and Karenia brevis and on nontoxic strains of A. tamarense, Prorocentrum minimum, and Scrippsiella trochoidea. Specific growth rates of G. moestrupii feeding on each of these dinoflagellates either increased continuously or became saturated with increasing mean prey concentration. The maximum specific growth rate of G. moestrupii feeding on toxic A. minutum (1.60/d) was higher than that when feeding on nontoxic S. trochoidea (1.50/d) or P. minimum (1.07/d). In addition, the maximum growth rate of G. moestrupii feeding on the toxic strain of A. tamarense (0.68/d) was similar to that when feeding on the nontoxic strain of A. tamarense (0.71/d). Furthermore, the maximum ingestion rate of G. moestrupii on A. minutum (2.6 ng C/grazer/d) was comparable to that of S. trochoidea (3.0 ng C/grazer/d). Additionally, the maximum ingestion rate of G. moestrupii on the toxic strain of A. tamarense (2.1 ng C/grazer/d) was higher than that when feeding on the nontoxic strain of A. tamarense (1.3 ng C/grazer/d). Thus, feeding by G. moestrupii is not suppressed by toxic dinoflagellate prey, suggesting that it is an effective protistan grazer of toxic dinoflagellates.

Ostreol A: a new cytotoxic compound isolated from the epiphytic dinoflagellate Ostreopsis cf. ovata from the coastal waters of Jeju Island, Korea.

Ostreol A was isolated from cultures of the epiphytic dinoflagellate Ostreopsis cf. ovata from the coastal waters of Jeju Island, Korea. The compound, a non-palytoxin derivative, has a polyhydroxy chain ending with the primary amino group and contains an amide bond, along with two tetrahydropyran rings in the chain. Its chemical structure was elucidated by nuclear magnetic resonance (NMR) spectroscopy methods and confirmed by mass analysis. The compound exhibited significant cytotoxicity in the brine shrimp lethality test at a concentration of 0.9µg/mL.

The neural selection and integration of actions and objects: an fMRI study.

There is considerable evidence that there are anatomically and functionally distinct pathways for action and object recognition. However, little is known about how information about action and objects is integrated. This study provides fMRI evidence for task-based selection of brain regions associated with action and object processing, and on how the congruency between the action and the object modulates neural response. Participants viewed videos of objects used in congruent or incongruent actions and attended either to the action or the object in a one-back procedure. Attending to the action led to increased responses in a fronto-parietal action-associated network. Attending to the object activated regions within a fronto-inferior temporal network. Stronger responses for congruent action-object clips occurred in bilateral parietal, inferior temporal, and putamen. Distinct cortical and thalamic regions were modulated by congruency in the different tasks. The results suggest that (i) selective attention to action and object information is mediated through separate networks, (ii) object-action congruency evokes responses in action planning regions, and (iii) the selective activation of nuclei within the thalamus provides a mechanism to integrate task goals in relation to the congruency of the perceptual information presented to the observer.

Gyrodinium moestrupii n. sp., a new planktonic heterotrophic dinoflagellate from the coastal waters of western Korea: morphology and ribosomal DNA gene sequence.

The heterotrophic dinoflagellate Gyrodinium moestrupii n. sp. is described based on live cells and cells prepared for light, scanning electron, and transmission electron microscopy. In addition, sequences of the small subunit (SSU), internal transcribed spacers (ITS1 and ITS2), 5.8S, and the large subunit (LSU) of the rDNA were analyzed. The cells have a slender, fusiform body, taper to a sharp point at both apices, and are widest in the middle. The conical episome and hyposome are equal in size. A distinct elliptical bisected apical groove (AG) is present. Gyrodinium moestrupii has longitudinal surface striations (LSS) containing 14 and 23 lines in the episome and hyposome, respectively, whereas Gyrodinium dominans, morphologically the most similar species, has 14 and 18 lines, respectively. In addition, the episome and hyposome of G. moestrupii show distinct twists to the right and left, respectively, unlike those of Gyrodinium gutrula or G. dominans, which are not markedly twisted. The cingulum is displaced by 0.3-0.4 × cell length. Length and width of cells starved for 2 d were 23.9-38.2 and 12.0-18.6 µm, respectively, whereas those of cells satiated with Alexandrium minutum were 30.1-61.4 and 20.7-35.6 µm, respectively. The cells contain a pusule system, trichocysts, a lamellar-like structure, and a fibrous bundle, but lack chloroplasts. The SSU rDNA sequence differed by 0.2-3.9% from those of the three most closely related sequenced species for which data are currently available: G. cf. gutrula (FN669511), G. dominans (FN669510), and Gyrodinium rubrum (AB120003). The LSU rDNA was 3.2-13.9% different from G. dominans (AY571370), Gyrodinium spirale (AY571371), and G. rubrum (AY571369). The phylogenetic trees demonstrated that this novel species belongs within the Gyrodinium clade. Based on the morphological and molecular data, we propose to name it G. moestrupii n. sp.

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.

Perceptual and motor-based responses to hand actions on objects: evidence from ERPs.

We carried out a study examining the electrophysiological responses when participants made object decisions to objects and non-objects subject to congruent and incongruent hand-grip actions. Despite the grip responses being irrelevant to the task, event-related potentials were sensitive to the handgrip. There were effects of grip congruency on both P1 and N1 components, over both posterior and motor cortices, with the effects emerging most strongly for familiar objects. In addition, enhanced lateralized readiness potentials were observed for incongruent grips. The results suggest that there are increased perceptual and motor-based responses to objects and object-like stimuli that are grasped correctly, even when the grip is irrelevant to the task. This is consistent with the automatic coding of potential appropriate actions based on visual information from objects in the environment.

Mixotrophy in the newly described phototrophic dinoflagellate Woloszynskia cincta from western Korean waters: feeding mechanism, prey species and effect of prey concentration.

Woloszynskia species are dinoflagellates in the order Suessiales inhabiting marine or freshwater environments; their ecophysiology has not been well investigated, in particular, their trophic modes have yet to be elucidated. Previous studies have reported that all Woloszynskia species are photosynthetic, although their mixotrophic abilities have not been explored. We isolated a dinoflagellate from coastal waters in western Korea and established clonal cultures of this dinoflagellate. On the basis of morphology and analyses of the small/large subunit rRNA gene (GenBank accession number=FR690459), we identified this dinoflagellate as Woloszynskia cincta. We further established that this dinoflagellate is a mixotrophic species. We found that W. cincta fed on algal prey using a peduncle. Among the diverse prey provided, W. cincta ingested those algal species that had equivalent spherical diameters (ESDs) ≤12.6 µm, exceptions being the diatom Skeletonema costatum and the dinoflagellate Prorocentrum minimum. However, W. cincta did not feed on larger algal species that had ESDs≥15 µm. The specific growth rates for W. cincta increased continuously with increasing mean prey concentration before saturating at a concentration of ca. 134 ng C/ml (1,340 cells/ml) when Heterosigma akashiwo was used as food. The maximum specific growth rate (i.e. mixotrophic growth) of W. cincta feeding on H. akashiwo was 0.499 d(-1) at 20 °C under illumination of 20 µE/m(2) /s on a 14:10 h light-dark cycle, whereas its growth rate (i.e. phototrophic growth) under the same light conditions without added prey was 0.040 d(-1). The maximum ingestion and clearance rates of W. cincta feeding on H. akashiwo were 0.49 ng C/grazer/d (4.9 cells/grazer/d) and 1.9 µl/grazer/h, respectively. The calculated grazing coefficients for W. cincta on co-occurring H. akashiwo were up to 1.1 d(-1). The results of the present study suggest that grazing by W. cincta can have a potentially considerable impact on prey algal populations.

Design, synthesis and identification of novel colchicine-derived immunosuppressant.

Synthesis and biological evaluation of various colchicine analogues through the mixed-lymphocyte reaction (MLR), lymphoproliferation, and inhibitory effects on the inflammatory genes are described. In addition, a new series of immunosuppressive agents developed on the structural basis of colchicine, as well as their structure-activity relationships is reported. The most potent analogue 20a exhibited an excellent immunosuppressive activity on in vivo skin-allograft model, which is comparable to that of cyclosporin A.

Effects of biological control of rice weevil by Anisopteromalus calandrae with a population of two Aspergillus spp.

In this study, we assessed the interaction occurring between the rice weevil and two storage molds (Aspergillus candidus Link and Aspergillus niger Van Tiegem) that prefer different moisture regimens under rice storage conditions. Rice weevil induced rapid population growth in both of the storage molds. The colony forming units (CFUs) of A. candidus and A. niger peaked at 10(9.00 +/- 0.02) and 10(7.72 +/- 0.03)/g, respectively. All of the rice grains were infested with the molds and eventually deteriorated; in the jars infested with A. candidus, no living weevils were found after 135 d. Suppression of the rice weevil by its larval parasitoid, Anisopteromalus calandrae (Howard), significantly retarded the growth of A. candidus but completely halted the growth of A. niger, which was replaced by xerophyllic molds including Aspergillus penicilloides Spegazzini and Wallemia sebi (Fries). Regression analyses showed that the total number of weevils was a significant factor explaining grain moisture content, which was in turn a significant factor in the growth of both mold species. The growth of A. niger was dependent on the grain moisture content (r2 = 0.52), thereby suggesting that the growth of A. niger was caused primarily by activity of the rice weevil and the resulting increased grain moisture content. However, 27% of the growth of A. candidus was explained by grain moisture contents, suggesting that a factor other than the grain moisture content may also affect its growth. Suppression of rice weevil by A. calandrae could induce an A. candidus-dominant molds community, which would be a factor for consideration in biological control program.

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 and grazing impact by the bloom-forming euglenophyte Eutreptiella eupharyngea on marine eubacteria and cyanobacteria.

The phototrophic euglenophyte Eutreptiella eupharyngea often causes blooms in the coastal waters of many countries, but its mode of nutrition has not been assessed. This species has previously been considered as exclusively auxotrophic. To explore whether E. eupharyngea is a mixotrophic species, the protoplasm of E. eupharyngea cells were examined using light, epifluorescence, and transmission electron microscopy after eubacteria, the cyanobacterium Synechococcus sp., and diverse algal species were provided as potential prey. Furthermore, the ingestion rates of E. eupharyngea KR on eubacteria or Synechococcus sp. as a function of prey concentration were measured. In addition, grazing by natural populations of euglenophytes on natural populations of eubacteria in Masan Bay was investigated. This study is the first to report that E. eupharyngea is a mixotrophic species. Among the potential prey organisms offered, E. eupharyngea fed only on eubacteria and Synechococcus sp., and the maximum ingestion rates of these two organisms measured in the laboratory were 5.7 and 0.7 cells predator-1 h-1, respectively. During the field experiments, the maximum ingestion rates and grazing impacts of euglenophytes, including E. eupharyngea, on natural populations of eubacteria were 11.8 cells predator-1 h-1 and 1.228 d-1, respectively. Therefore, euglenophytes could potentially have a considerable grazing impact on marine bacterial populations.

Colchicine-derived compound CT20126 promotes skin allograft survival by regulating the balance of Th1 and Th2 cytokine production.

Colchicine has been shown to regulate the expression of inflammatory gene, but this compound possesses much weaker anti-inflammatory activity. In this study, we synthesized a new colchicine derivative CT20126 and examined its immunomodulatory property. CT20126 was found to have immunosuppressive effects by inhibiting lymphocyte proliferation without cytotoxicity and effectively inhibit the transcriptional expression of the inflammatory genes, iNOS, TNF-alpha, and IL-1beta, in macrophages stimulated by LPS. This effect was nearly comparable to that of cyclosporine A. This compound also significantly suppressed the production of nitric oxide and Th1-related pro-inflammatory cytokines, IL-1beta, TNF-alpha, and IL-2, with minimal suppression of Th2-related anti-inflammatory cytokines IL-4 and IL-10 in the sponge matrix allograft model. Moreover, administration of CT20126 prolonged the survival of allograft skins from BALB/c mice (H-2(d)) to the dorsum of C57BL/6 (H-2(b)) mice. The in vivo immune suppressive effects of CT20126 were similar to that of cyclosporine A. These results indicate that this compound may have potential therapeutic value for transplantation rejection and other inflammatory diseases.

Mixotrophic ability of the phototrophic dinoflagellates Alexandrium andersonii, A. affine, and A. fraterculus.

The dinoflagellate Alexandrium spp. have received much attention due to their harmful effects on diverse marine organisms, including commercially important species. For minimizing loss due to red tides or blooms of Alexandrium spp., it is very important to understand the eco-physiology of each Alexandrium species and to predict its population dynamics. Its trophic mode (i.e., exclusively autotrophic or mixotrophic) is one of the most critical parameters in establishing prediction models. However, among the 35 Alexandrium species so far described, only six Alexandrium species have been revealed to be mixotrophic. Thus, mixotrophic ability of the other Alexandrium species should be explored. In the present study, whether each of three Alexandrium species (A. andersonii, A. affine, and A. fraterculus) isolated from Korean waters has or lacks mixotrophic ability, was investigated. When diets of diverse algal prey, cyanobacteria, and bacteria sized micro-beads were provided, A. andersonii was able to feed on the prasinophyte Pyramimonas sp., the cryptophyte Teleaulax sp., and the dinoflagellate Heterocapsa rotundata, whereas neither A. affine nor A. fraterculus fed on any prey item. Moreover, mixotrophy elevated the growth rate of A. andersonii. The maximum mixotrophic growth rates of A. andersonii on Pyramimonas sp. under a 14:10h light/dark cycle of 20µEm-2s-1 was 0.432d-1, while the autotrophic growth rate was 0.243d-1. With increasing mean prey concentration, the ingestion rate of A. andersonii increased rapidly at prey concentrations <650ngCml-1 (ca. 16,240 cellsml-1), but became saturated at the higher prey concentrations. The maximum ingestion rate by A. andersonii of Pyramimonas sp. was 1.03ngC predator-1d-1 (25.6 cells predator-1d-1). This evidence suggests that the mixotrophic ability of A. andersonii should be taken into consideration in predicting the outbreak, persistence, and decline of its harmful algal blooms.

Attending to the possibilities of action.

Actions taking place in the environment are critical for our survival. We review evidence on attention to action, drawing on sets of converging evidence from neuropsychological patients through to studies of the time course and neural locus of action-based cueing of attention in normal observers. We show that the presence of action relations between stimuli helps reduce visual extinction in patients with limited attention to the contralesional side of space, while the first saccades made by normal observers and early perceptual and attentional responses measured using electroencephalography/event-related potentials are modulated by preparation of action and by seeing objects being grasped correctly or incorrectly for action. With both normal observers and patients, there is evidence for two components to these effects based on both visual perceptual and motor-based responses. While the perceptual responses reflect factors such as the visual familiarity of the action-related information, the motor response component is determined by factors such as the alignment of the objects with the observer's effectors and not by the visual familiarity of the stimuli. In addition to this, we suggest that action relations between stimuli can be coded pre-attentively, in the absence of attention to the stimulus, and action relations cue perceptual and motor responses rapidly and automatically. At present, formal theories of visual attention are not set up to account for these action-related effects; we suggest ways that theories could be expected to enable action effects to be incorporated.

The paired-object affordance effect.

We demonstrate that right-handed participants make speeded classification responses to pairs of objects that appear in standard co-locations for right-handed actions relative to when they appear in reflected locations. These effects are greater when participants "weight" information for action when deciding if 2 objects are typically used together, compared with deciding if objects typically occur in a given context. The effects are enhanced, and affect both types of decision, when an agent is shown holding the objects. However, the effects are eliminated when the objects are not viewed from the first-person perspective and when words are presented rather than objects. The data suggest that (a) participants are sensitive to whether objects are positioned correctly for their own actions, (b) the position information is coded within an egocentric reference frame, (c) the critical representation involved is visual and not semantic, and (d) the effects are enhanced by a sense of agency. The results can be interpreted within a dual-route framework for action retrieval in which a direct visual route is influenced by affordances for action.

Neuropsychological evidence for visual- and motor-based affordance: effects of reference frame and object-hand congruence.

Two experiments are reported that use patients with visual extinction to examine how visual attention is influenced by action information in images. In Experiment 1 patients saw images of objects that were either correctly or incorrectly colocated for action, with the objects held by hands that were congruent or incongruent with those used premorbidly by the patients. The images were also shown from a 1st- and 3rd-person perspective. There was an overall reduction in extinction for objects colocated for action. In addition, there was an extra benefit when the objects were held in hands congruent with those used by the patients and when the objects were seen from a 1st-person perspective. This last result fits with an effect of motor simulation, over and above a purely visual effect based on positioning objects correctly for action. Experiment 2 showed that effects of hand congruence could emerge with images depicted from a 3rd-person perspective when patients saw themselves holding the objects. The data indicate 2 effects of action information on extinction: (a) an effect of colocating objects for action, which does not depend on a self-reference frame (a visual effect), and (b) an effect sensitive to object-hand congruence, which does depend on a self-reference frame (a motor-based effect). The self-reference frame is induced when stimuli are viewed from a 1st-person perspective and when an image of the self is seen from a 3rd-person perspective. Both visual and motor-based effects of action information facilitate the spread of attention across objects.

The interaction of attention and action: from seeing action to acting on perception.

We discuss evidence indicating that human visual attention is strongly modulated by the potential of objects for action. The possibility of action between multiple objects enables the objects to be attended as a single group, and the fit between individual objects in a group and the action that can be performed influences responses to group members. In addition, having a goal state to perform a particular action affects the stimuli that are selected along with the features and area of space that is attended. These effects of action may reflect statistical learning between environmental cues that are linked by action and/or the coupling between perception and action systems in the brain. The data support the argument that visual selection is a flexible process that emerges as a need to prioritize objects for action.

Attention and its coupling to action.

We discuss two commentaries that we have received on our target article (Humphreys et al., 2010). We elaborate on the evidence for action effects on extinction and discuss whether these effects occur pre or post the selection of a response. In addition, we discuss the neural basis of the effects of action relations on extinction and on the generalization of results on action relations to real-world examples.