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The orbital degree of freedom, strongly coupled with the lattice and spin, is an important factor when designing correlated functions. Whether the long-range orbital order is stable at reduced dimensions and, if not, what the critical thickness is remains a tantalizing question. Here, we report the melting of orbital ordering, observed by controlling the dimensionality of the canonical e

Mobile defects in solid-state materials play a significant role in memristive switching and energy-efficient neuromorphic computation. Techniques for confining and manipulating point defects may have great promise for low-dimensional memories. Here, we report the spontaneous gathering of oxygen vacancies at strain-relaxed crack walls in SrTiO

Carbon dioxide (CO2) is being continuously discharged into the atmosphere and is now at a concentration sufficient to cause ocean acidification. In particular, it has been reported that changes in carbonate concentration in seawater by ocean acidification can inhibit olfactory function and predator avoidance ability in fish and affect their circadian rhythm. However, although increased CO2 concentration in seawater is an important environmental factor affecting fish survival, only a few studies have been conducted to evaluate the effect of CO2 and different photoperiods. Therefore, in this study, we investigated changes in the circadian rhythm of juvenile olive flounder (Paralichthys olivaceus) under different light conditions (12 h ligh:12 h dark; constant dark; constant light) and CO2 exposure levels (pH 8.1, 7.8, and 7.5), by analyzing changes in plasma concentrations of Cryptochrome1 and Period2, which are secreted during the day (light conditions), and melatonin, which is secreted at night (dark conditions). CO2 exposure led to phase shifts (temporarily abolished, phase delayed, or reversed) in the rhythm of juveniles. In conclusion, CO2 exposure, along with changes in photoperiods, increases the disturbance in the circadian rhythm of juvenile P. olivaceus.

The neurotoxin domoic acid (DA) is produced by Pseudo-nitzschia spp. during harmful algal blooms and is linked to amnesic shellfish poisoning. This toxin is particularly problematic in the culture of bivalves for human consumption. In this study, we exposed bay scallops to 20, 40, and 60 ng/ml DA and examined toxin accumulation and stress response at 3, 6, 12, 24, 36, and 48 h of exposure. Oxidative stress was determined by measuring the levels of superoxide dismutase (SOD), catalase (CAT), heat shock protein 90 (HSP90), and metallothionein (MT) in the digestive diverticula and/or hemolymph and by determining H2O2 concentration in hemolymph. We also observed histological changes to gills following exposure to DA in order to determine changes in melanization. We found that scallops accumulated a maximum of 2.61 ng/ml DA in their digestive diverticula when exposed to 60 ng/ml. Stress indices rose under higher DA concentrations, and HSP levels increased under exposure to higher concentrations of DA. However, mRNA expression and activity of other stress parameters showed peaks at different times during exposure, with subsequent declines. Epithelial melanization of gills indicated a strong positive response to DA at 60 ng/ml for 48 h (P

The seasonal variations in species composition of set net fisheries were investigated in the eastern coast of Korea, from 2007 to 2008. In total, 51 species were found that were classified into 15 orders and 33 families. The water temperature of the study area was 0.1–2.1 °C during the study period, which was higher than the average water temperature in the last decade. Monthly variation in the number of species peaked twice, in May (spring) and November (autumn) when the water temperature increased and decreased, respectively, and monthly variation in the number of individuals showed a remarkably high trend in winter and autumn and was mainly caused by large migratory species. Based on the cluster analysis of the 18 most dominant species with more than 0.4% of the total number of individuals, we divided the species composition and community structure into three groups: fishes with temporary appearance (Group A), fishes with long-term appearance (Group B), and dominant pelagic fishes appearing with long-term appearance (Group C). We could conclude that seasonal variation in the fish community structure was mainly caused by pelagic migration of species under high water temperature conditions during the study period.

The use of fossil fuels by anthropogenic activities causes ocean acidification and warming, and these changes in the marine environment can negatively affect the metabolism, growth, and survival of fish. In the present study, we evaluated the ability of olive flounder Paralichthys olivaceus to cope with future marine environmental changes by investigating the oxidative stress (cortisol, HSP70), antioxidant enzyme (superoxide dismutase; SOD, catalase; CAT) activity, and apoptosis (caspase-3) after exposure to control conditions (20 °C and pH 8.1), warming (30 °C) and acidification (pH 7.5) conditions, and a combined environment (30 °C and pH 7.5) for 28 days. Under warming conditions, increased oxidative stress, activity of antioxidant enzymes, and apoptosis were observed. Acidifying conditions showed negative effects at the beginning of exposure, but these effects were offset over time. Even in a combined environment of acidification and warming, negative effects were seen only at the beginning of exposure and were not sustained. In conclusion, the effects of acidification on oxidative stress, antioxidant response, and apoptosis in P. olivaceus did not exceed the effects of warming. These results suggest that P. olivaceus can cope with the predicted future acidifying environment.

The Jahn–Teller (JT) effect, through geometric deformation of molecules or local ionic lattices, lowers the overall energy of the system by removing electron degeneracy from partially occupied orbitals. Crystal symmetry lowered by JT distortion inevitably creates multiple variants of elastic and orbital-anisotropic states. Visualization and control of the domain/wall textures create a cornerstone to understand various correlated phenomena and explore wall properties. Here, we report the real-space observation of JT phonon and orbiton-related domains in a LaMnO3 thin film using confocal Raman spectromicroscopy. The characteristic symmetries of the JT-originated Raman modes allow us to detect and visualize the local population and orientation of the JT planes. Combined with a crystal structural analysis, we find that the formation of ferroelastic domains with W or W’ walls provides the basic framework for understanding JT domain textures. Furthermore, we demonstrate the JT domains can be manipulated by applying local external stress. Our findings provide a useful pathway for mechanically-tunable orbitronic applications.

Reproductive hormones play essential roles in the control of reproduction and gonadal maturation in fish. The purpose of this study was to determine the effects of cortisol administration (10 µg/g or 50 µg/g) or red light irradiation at two intensities (0.5 W/m2 or 1.0 W/m2) on the reproductive hormones in goldfish (Carassius auratus). The effects of different treatments were analyzed by determining the mRNA expression levels of gonadotropin-inhibitory hormone receptor (GnIH-R), chicken gonadotropin-releasing hormone (cGnRH-II), salmon GnRH (sGnRH), FSHβ, LHβ, and plasma testosterone and the level of 17β-estradiol for 48 h. Additionally, by double immunofluorescence staining, we detected the expression of both GnIH and GnRH in the diencephalons of goldfish brains. The mRNA expression of GnIH-R was significantly higher in the cortisol group and red light-irradiated group from 3 to 48 h than in the control group. Additionally, the mRNA levels of cGnRH-II, sGnRH, FSHβ, LHβ, testosterone, and 17β-estradiol were significantly lower in the cortisol group than in the other groups from 3 to 48 h. These results indicated that both cortisol and red light-emitting diode (LED) light increased GnIH expression and inhibited GnRH expression. In particular, red light irradiation suppressed reproductive responses as much as the cortisol treatment at 48 h. Thus, it could be an alternative method for suppressing reproductive responses in future aquacultures.

High-speed, high-performance electrochromic devices can be designed using unique solid-solid phase changes induced by oxygen flow., Mobile oxygen vacancies offer a substantial potential to broaden the range of optical functionalities of complex transition metal oxides due to their high mobility and the interplay with correlated electrons. Here, we report a large electro-absorptive optical variation induced by a topotactic transition via oxygen vacancy fluidic motion in calcium ferrite with large-scale uniformity. The coloration efficiency reaches ~80 cm2 C−1, which means that a 300-nm-thick layer blocks 99% of transmitted visible light by the electrical switching. By tracking the color propagation, oxygen vacancy mobility can be estimated to be 10−8 cm2 s−1 V−1 near 300°C, which is a giant value attained due to the mosaic pseudomonoclinic film stabilized on LaAlO3 substrate. First-principles calculations reveal that the defect density modulation associated with hole charge injection causes a prominent change in electron correlation, resulting in the light absorption modulation. Our findings will pave the pathway for practical topotactic electrochromic applications.

Climate change due to increasing CO

Oxygen vacancies are ubiquitous in oxides, and taking advantage of their mobility is the cornerstone for a variety of future applications. The visualization and quantification of collective defect flow based on electrochromism is a powerful approach to explore oxygen kinetics and electrochemical reaction even in cases that electronic conduction is considerably mixed, but whether or not the measured kinetic properties harmonize with those obtained by the conventional impedance spectroscopy remains veiled. Here, we identify complementary relationships between the two methods by investigating the oxygen vacancy transport in Ca 30%-doped bismuth ferrite thin films epitaxially grown on SrTiO3 (110) substrates. We find that the activation energy of ionic hopping is 0.78 (or 0.92 eV) for the application of an electric bias along [001] (or [1 1 ¯0]) due to the grain elongation along [001]. We anneal the films in an N2 gas environment at high temperatures to suppress the electronic contribution for access to standard impedance spectroscopy. The oxygen kinetic properties obtained from the two methods are consistent with each other, complementarily revealing the collective phase evolution as well as the ionic impedance of the bulk, grain boundary, and interfacial regions. These comparative works provide useful insights into ionic defect conduction in oxides in an intuitive and quantitative manner.

Widely distributed from the northern coast of Vietnam to the northern Japan, the limpet Cellana grata (Gould, 1859) occurs commonly on the south and east coasts of Korea. Despite their wide distribution range, few studies have investigated the annual gametogenesis and reproductive effort of C. grata. In an attempt to understand the reproductive physiology of the limpet, we investigated the annual gametogenesis and reproductive effort of C. grata from Ulleungdo Island off the east coast of Korea. Histology revealed that the gonial mitosis commenced in January, as the female exhibited small oogonia (10–40 μm) in the follicle. From March to June, the oocyte size increased dramatically, and fully mature eggs (110–170 μm in diameter) appeared in early summer. First spawning males and females were observed in July, as the surface seawater temperature (SST) reached 22.1°C. The spawning male and females could be observed until the end of December. Gonad somatic index (GSI), a ratio of gonad mass to the total tissue weight, of the male ranged from 0.6 (April) to 17.9 (July), while the female GSI varied from 1.0 (February) to 18.3 (July). GSI of male and female declined rapidly from July to August, suggesting that the major purse of the spawning at the study site was between July and August. Our study suggested that the commercial catch of C. grata during July and August must be suspended at Ulleungdo Island, in order to protect the spawning limpets, which enhances C. grata recruitment and the population.

In December 2007, > 150 km of the West coast of Korea were heavily polluted by crude oil leaked from the oil tanker Hebei Spirit , leading to mass mortality of bivalve mollusks on the intertidal areas. Two years after, mussels Mytilus galloprovincialis were collected from two impacted sites to investigate sub-lethal effects of the oil spill. Tissue content in polycyclic aromatic hydrocarbons (PAHs), hemocyte parameters, reproductive status and energetic reserves were analyzed. PAHs in tissues of mussels as well as hemocyte parameters were not different between impacted and control sites. Energetic reserves were altered in mussels from the impacted sites. Glycogen content remained low at polluted sites, whatever the season. Two years after the Hebei Spirit oil spill, mussels then presented altered energetic metabolism. Further investigations are thus warranted to monitor the sustainability of mussel populations on the oil spilled West coast of Korea.

Two years after the Hebei Spirit oil spill occurred off the west coast of Korea, we determined sub-lethal effects of the spilled oil on hemocyte parameters of Ruditapes philippinarum in the damaged areas. Clams in the spilled sites displayed unusually high proportion of granulocytes, which may result in higher phagocytosis capacity and reactive oxygen species production. Hemocytes in clams from the polluted sites also displayed less DNA damage and mortality than in the control site, possibly due to a faster phagocytosis of the impaired cells. Glycogen, the major energetic reserve, was depleted in clams from the spilled sites, potentially due to energetic consumption for maintenance of a large pool of granulocytes, detoxification processes and oxidative stress. Modified hemocyte parameters in clams in the spilled area, may reflect sub-lethal physiological stresses caused by the residual oils in the sediment, in conjunction with environmental modifications such as food availability and pathogens pattern.

This study examined the relationship between macrobenthic distribution patterns and environmental factors in salt marsh vegetation in Donggeomdo, Ganghwa on the west coast of Korea. Nine stations were fixed on a transect across the salt marsh vegetation, and field sampling was carried out monthly from July 1997 to June 1998. A total of 38 species of macrobenthos were recorded: each of faunal groups, 13 (34.2%) Arthropoda, 12 (31.6%) Polychaeta, 8 (21.1%) Mollusca, and 5 (13.2%) others. The mean density was 2,659 individuals/㎡, with a mean biomass of 178.6 gWWt/㎡. Mollusca dominated in terms of abundance and biomass, with a mean density of 2,172 individuals/㎡ (81.7%) and a mean biomass of 131.9 gWWt/㎡ (73.9%). The number of species decreased in winter (January−February), while mean density increased in the spring (May−June). The biomass was relatively in Summer and Fall (July−November), than any other season. The number of species was high in pure stands of Suaeda japonica in the lower salt marsh vegetation, and the mean density and biomass were high in mixed halophyte communities in the middle salt marsh vegetation. Two Mollusca, the bivalve Glauconome chinensis and gastropod Assiminea lutea, were dominant. The densities of these two species were high in mixed halophyte communities in the middle salt marsh vegetation. Non-metric multi-dimensional scaling (nMDS) showed that the study area could be divided into four groups corresponding to the vertical distribution of tidal levels and halophytes. Spearman’s rank correlation revealed that the distribution patterns and community structure of macrobenthos were related to environment variables such as salinity of the substrates, exposure time, and grain size compositions of the sediment in the salt marsh vegetation. Particularly, the distribution and density of some dominant species showed differences along the vertical distributions of halophytes.

This study examined the capture rates and prey digestion of three corals species in two genera (Acropora and Pocillopora) found dominantly in Thailand and the Federated States of Micronesia using Artemia salina nauplii as a food source. In addition, feeding during day and night times of corals was investigated. Results showed that all three coral species, namely, Acropora millepora, Acropora nobilis, and Pocillopora damicornis captured and consumed A. salina nauplii under both light and dark conditions. The capture rates of the three species ranged between 0.44 and 2.39 individuals/polyp/12 h. The results also showed complete digestions of A. salina nauplii by A. millepora and A. nobilis after 2 h, whereas P. damicornis took 2.5 h to complete the prey digestion. Even though feeding corals with Artemia is not a novel implication since this is widely used, the results of optimum daily feeding frequency of corals by Artemia may be applied for optimum corals growth and survival in captivity or aquarium.

Marine microplastic pollution poses a threat to aquatic organisms, including bivalves. In this study, we investigated the accumulation of microplastics and their elicited antioxidant stress response in the bay scallop Argopecten irradians. Scallops were exposed to 1 μm diameter micro-polystyrene (MP) beads at 10, 100, and 1000 beads/mL concentrations for a 7 day period. Bead presence in the digestive diverticula and defense responses in the digestive diverticula and hemolymph were measured at 1, 3, 5, and 7 days. The activity and expression of the antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT) and H2O2 in the digestive diverticula and/or hemolymph of scallops increased with microplastic concentration and exposure duration. These results suggest that microplastics can accumulate in the digestive diverticula of A. irradians, and that exposure to microplastics induces oxidative stress in bivalves. It is likely that exposure to high concentrations of micro- or nano-sized plastic particles could potentially have adverse effects in bivalves.

The ultrafast motion of oxygen vacancies in solids is crucial for various future applications, such as oxide electrolytes. Visualization and quantification can offer unforeseen opportunities to probe the collective dynamics of defects in crystalline solids, but little research has been conducted on oxygen vacancy electromigration using these approaches. Here, we visualize electric-field-induced creation and propagation of oxygen-vacancy-rich and -poor competing phases and their interface with optical contrast in Ca-substituted BiFeO3 that contains a high density of mobile oxygen vacancies. We quantitatively determined the drift velocity of collective migration to be on the order of 100 μm s−1 with an activation barrier of 0.79 eV, indicating a significantly large ionic mobility of 2 × 10−6 cm2 s−1 V−1 at a remarkably low temperature of 390 °C. In addition, visualization enables direct observation of fluidic behavior, such as the enhancement of conduction at channel edges, which results in U-shaped viscous propagation of the phase boundary and turbulence under a reverse electric field. All of these results provide new insights into the collective motion of defects. The collective propagation of defects in an oxide material has been visualized by researchers in South Korea and the USA. Most crystalline materials are imperfect. One type of imperfection, known as a vacancy, is the absence of an atom from the crystal lattice. These vacancies move through the material as surrounding atoms shift to fill the empty spot. A better understanding of this motion could aid the development of novel memories, solid oxide fuel cells and batteries. Chan-Ho Yang from the Korea Advanced Institute of Science and Technology, Daejeon, and colleagues recorded the movement of oxygen vacancies in calcium-substituted BiFeO3 because of the color difference between regions of high and low vacancy concentration. This ability to visualize oxygen-vacancies in real-time offers an opportunity to measure their movement and better understand defect-induced material changes. We visualize an electric-field-induced collective propagation of oxygen vacancies spontaneously contained in Ca-substituted BiFeO3 films, using the fact that the oxygen-rich and poor regions have different color contrasts and thus they are optically distinguishable forming a sharp boundary. We quantitatively determine the drift velocity to be of the order of 100 μm s−1 with an activation barrier of 0.79 eV indicating a significantly large ionic mobility 2 × 10−6 cm2 s−1 V−1 at a remarkably low temperature of 390 °C. Furthermore, U-shaped propagation and turbulence under backward electric field provide insights into fluidic defects in crystalline solids.

Pen shell is one of the largest marine bivalves inhabiting shallow subtidal soft bottoms in the west Pacific and Indian Oceans. In Korea, the comb pen shell Atrina pectinata fisheries has been established on the south and west coasts. Recently, a pen shell population has been discovered from a subtidal sand flat (25–30 m depth) in Ulleungdo Island located in the East Sea of Korea, suggesting a potential shellfish resource in this area. In the present study, we first surveyed the population density and size of the unique pen shell using SCUBA, and identified the pen shell to species level using mitochondrial cytochrome oxidase I gene (COI) sequence. An underwater survey carried out from July to September 2013 revealed that populations of pen shell patched on subtidal sand flat at a depth of 20–25 m. Grain size analysis indicated that sand particles accounted for 99% of the 600 × 700 m sand flat. The underwater survey also indicated that density of the pen shell ranged between 6–19 ind/m2, with a mean of 11 ind/m2. Shell height (i.e. longest axis of the shell) of the pen shell on the sand flat varied between 17.2 cm to 28.8 cm, with a mean of 25.1 cm, and the age was estimated to range between 1.5–7.5 yrs, with a mean of 5 yr. COI DNA sequence obtained from the pen shell in this study showed 98.9–99.2% similarity to Atrina pectinata (Linnaeus 1767) reported from Japan. In the cluster analysis, the COI DNA sequence of the pen shells from Ulleungdo Island was grouped with A. pectinata reported from Japan and China, indicating that the pen shell discovered in this study was A. pectinata, commonly distributed on the west and south coasts of Korea.

The Hebei Spirit oil spill in December 2007 at Taean off the west coast of Korea was the largest oil tanker accident in Korea. However, the impact of the spill on physiology of benthic animals remains largely unknown. Two-years after the accident, we compared reproductive effort and annual gametogenesis of the wild Pacific oyster Crassostrea gigas , residing at oil spill site with a control oyster population in Incheon Bay, North-West coast of Korea. Results showed that the oyster sampled from the oil spill site showed a significantly higher (279.0 mg standard animal − 1 , P − 1 , P −1 , P −1 , P − 1 , P − 1 , P

Mytilus coruscus is a cold water mussel commonly occurring on shallow subtidal rocky substrata along the east coast of Korea. Despite its abundance, there have only been a few studies conducted reporting on its biology and ecology. In this study, we investigated the immune-related activities of hemocytes of M. coruscus using light microscopy and flow cytometry. Based on the morphology and cellular activities, 3 types of hemocytes were identified, as granulocytes, hyalinocytes, and blast-like cells. Granulocytes, containing numerous intra-cytoplasmic granules, were intermediate-size (11.8μm) and the most abundant cells (70.2%), while hyalinocytes were the largest cells (16.0μm), with no or few granules in their cytoplasm. The granulocytes exhibited higher lysosomal content, phagocytosis activity and oxidative capacities than the hyalinocytes. In contrast, the blast-like cells were the smallest cells (6.4μm) and displayed a lack of phagocytosis and oxidative capacities. In M. coruscus, the granulocytes appear as the major cell type involved in cellular defense, whereas the blast-like cells may not be directly involved in cell-mediated immune response.

Spirulina is a photosynthetic cyanobacterium rich in protein, polyunsaturated fatty acids, minerals and vitamins. Spirulina spp. are produced in fresh water, although freshwater shortages and the high-cost of feed stock carbon limit Spirulina production. Thus, use of seawater with low-cost carbon should be evaluated. Conversely, Ca 2 + and Mg 2 + of natural seawater (NSW) cause milky turbidity and nutrient precipitation when used in Spirulina culture medium. Here, NSW was pretreated with bituminous coal and NaOH to sediment Ca 2 + and Mg 2 + and obtain total organic carbon (TOC)-enriched pretreated seawater supernatant (PSWS), which was used to formulate Spirulina maxima culture medium. Pretreatment of NSW with bituminous coal and NaOH showed Ca 2 + and Mg 2 + precipitation rates of 32.52% and 99.91%, respectively, while TOC increased 6.97-fold in PSWS compared to NSW. The PSWS was 90–93% of NSW by volume, excluding sediment. The dry biomass production was 1.55 and 1.57 g L − 1 and the chlorophyll a content was 13.75 and 17.90 mg L − 1 in SOT and formulated AKSM-2-1 media, respectively. The maximum specific growth rate (μ max day − 1 ) and biomass productivity of S. maxima were 0.283 and 0.284 day − 1 and 1.97 and 2.00 g L − 1 day − 1 in SOT and formulated media, respectively. The biochemical composition and phycocyanin content were similar in the biomass of both media. Biomass production costs were ca. threefold lower in formulated medium than SOT medium. Therefore, S. maxima can be produced at lower costs using NSW following our method.

We examined trophic relationships in a newly established community 1.5 years after the Hebei Spirit oil spill on the west coast of Korea. Carbon and nitrogen stable isotope ratios in consumers and their potential food sources were compared between the oil-spill site and reference site, located 13.5 km from the oil-spill spot. The isotopic mixing model and a novel circular statistics rejected the influx of petrogenic carbon into the community and identified spatial consistencies such as the high contributions of microphytobenthos, food-chain length, and the isotopic niche of each feeding guild between sites. We suggested that high level of trophic plasticity and the prevalence of omnivory of consumers may promote the robustness of food web against the oil contamination. Furthermore, we highlighted the need of holistic approaches including different functional groups to quantify changes in the food web structure and assess the influence of different perturbations including oil spill.

This study was conducted to investigate the reproductive characteristics of the humbug damselfish, Dascyllus aruanus, through the measurement of gonadosomatic indices (GSI) and histological examination of the gonads. Fish were collected from Chuuk Lagoon, Micronesia (7°27′N; 151°53′E), between August 2009 and July 2010. Overall, the functional sex ratio was approximately 1:1; however, there was a female bias in the smaller size range (35–40 mm standard length [SL]) and male bias in the larger size range (45–60 mm in SL). The process of oocyte development exhibited a group synchronous pattern, from the vitellogenic phase oocytes in the gonads following the two clutches of oocytes, as the primary growth stage and yolk vesicle stage. The testis with an ovarian lumen exists as a central slit, and the sperm ducts extend into the medial hilar region of the gonads, indicating that males of D. aruanus have a secondary testis of protogynous species. Monthly variations in the GSI and evolution of gonad status indicated that reproductive activity in this species occurs throughout the year in Chuuk Lagoon, Micronesia.

In marine bivalve aquaculture, mortality is a major problem for sustainability of the industry. Mortalities usually result from complex interactions in which the physiological status is suspected to play a major role. In many bivalves, spawning appears as a critical period. Spawning is an energy demanding process potentially resulting in immunodepression and higher susceptibility to pathogenic infection. In an effort to understand the actual impacts of spawning on the cellular defense system (i.e., hemocytes) of the Manila clam Ruditapes philippinarum, we collected clams on a one-time sampling during early post-spawning period. We then applied, for the first time, a histology–flow cytometry combined approach to these animals. Hemocyte parameters, including concentration, sub-populations, mortality, phagocytosis capacity and reactive oxygen species production were analyzed along with gender, condition index as well as the tissue protein and carbohydrate levels. Among the 200 clams analyzed, 60.5% were spent, 24% spawning, 12% resting and 3.5% ripe and ready for spawning. No gender differences could be observed among all parameters and no correlation was determined between the protozoan parasite Perkinsus olseni infection intensity and the immune parameters. CI and tissue protein level of spawning and post-spawning (spent and resting) clams were significantly lower than those of pre-spawning (ripe) clams. The concentration of hemocytes tended to decline from ripe to spent clams, partly because of a concomitant increase of cell mortality and, most of all, a decrease in the quantity of circulating granulocytes. The decline in circulating granulocytes also resulted in a reduced phagocytosis capacity (% of cells able to phagocytise). At the animal scale, these observations support a depression of the global immune defense of spawning and post-spawning clams. However, at the cellular scale, remaining circulating cells did not display signs of stress nor altered metabolism. Indeed, phagocytosis, as the number of beads ingested per cell, was normal and no oxidative stress could be detected. Further studies will be necessary to determine if these hemocytes already reached their limit of stress tolerance, and to potentially help develop immunoprotective food additives for the aquaculture industry.

A strain designated as S85(T) was isolated from a seaweed collected from coastal area of Chuuk State in Micronesia. The strain was gram-negative, rod-shaped, and non-motile and formed yellow colonies on the SWY agar (0.2 % yeast extract and 1.5 % agar in seawater) and Marine agar 2216. The strain grew at pH 5-9 (optimum, pH 8), at 15-40 °C (optimum, 25-28 °C), and with 1-9 % (w/v) NaCl (optimum, 3 %). The phylogenetic analysis based on 16S rRNA gene sequence showed that strain S85(T) was related to Lutibacter litoralis CL-TF09(T) and Maritimimonas rapanae A31(T) with 91.4 % and with 90.5 % similarity, respectively. The dominant fatty acids were iso-C15:0, iso-C15:0 3-OH and iso-C17:0 3-OH, C16:0 3-OH and summed feature 3 (C16:1 ω7c and/or iso-C15:0 2-OH). The major isoprenoid quinone was MK-6. The DNA G+C content of the type strain was 34.6 mol %. The major polar lipids were phosphatidylethanolamine, an unknown glycolipid and two unknown polar lipids. Based on this polyphasic taxonomic data, strain S85(T) stands for a novel species of a new genus, and we propose the name Ochrovirga pacifica gen. nov., sp. nov. The type strain of O. pacifica is S85(T) (=KCCM 90106 =JCM 18327(T)).

Ionic migration is a key ingredient for applications such as oxide electrolytes and resistive switching memories. We investigate the evolution of ionic conduction pathways based on optical contrast in an epitaxial Bi0.7Ca0.3FeO3−δ thin film where oxygen vacancies are spontaneously produced. We visualize electroforming processes in the hundred-micrometer-scale material channels between coplanar electrodes with a constant electric bias at an elevated temperature, systematically varying the channel orientation with respect to the crystal axis. At the initial stage of electroforming, conducting filaments are created and propagate nearly along the crystal axes ⟨100⟩. The local density of conducting filament regions increases with the elapsed time of bias application and also exhibits a linear dependence on the spatial position at a given time. We also find that the filament-type ionic conduction is abruptly transformed to the bulk conduction when the filament density reaches ∼30%. These results offer useful insight into collective ionic migration in crystalline solids.