The effect of temperature on the duration of spawning markers—migratory-nucleus and hydrated oocytes and postovulatory follicles—in the multiple-batch spawner Japanese flounder (Paralichthys olivaceus)

The duration of spawning markers (e.g. signs of previous or imminent spawnings) is essential information for estimating spawning frequency of fish. In this study, the effect of temperature on the duration of spawning markers (i.e., oocytes at early migratory nucleus, late migratory nucleus, and hydrated stages, as well as new postovulatory follicles) of an indeterminate multiple-batch spawner, Japanese f lounder (Paralichthys olivaceus), was evaluated. Cannulation was performed to remove samples of oocytes, eggs, and postovulatory follicles in individual females at 2–4 hour intervals over 27–48 hours. The duration of spawning markers was successfully evaluated in 14 trials ranging between 9.2° and 22.6°C for six females (total length 484–730 mm). The durations of spawning markers decreased exponentially with temperature and were seen to decrease by a factor of 0.16, 0.36, 0.30, and 0.31 as temperature increased by 10°C for oocytes at early migratory nucleus, late migratory nucleus, and hydrated stages, and new postovulatory follicles, respectively. Thus, temperature should be considered when estimating spawning frequency from these spawning markers, especially for those fish that do not spawn synchronously in the population

Diel feeding rhythms, daily ration, and seasonal changes thereof in marbled flounder Pseudopleuronectes yokohamae

This paper aims to assess the diel feeding pattern and seasonal variation in the daily ration of immature and mature marbled flounder (Pseudopleuronectes yokohamae ). A day‐night collection by bottom trawls was conducted in Sendai Bay in July 2014. Marbled flounder (131–493 mm total length; Number of collected individuals = 1830, Number of analyzed individuals = 497) fed mainly on polychaetes during the day. At night, stomach content weight decreased with time, but the weight and proportion of bivalve siphons were consistently higher at night than during the day, suggesting nocturnal feeding by the flounder on bivalve siphons. Daily ration was greater in females (<300 mm: 2.6%–3.2% body weight; ≥300 mm: 1.5%–2.5%) than in males (<300 mm: 1.7%–2.6%; ≥300 mm: 1.3%–1.9%). Seasonal surveys were also carried out, and the greater ration in females than males were consistent throughout the year, suggesting that greater growth in females than males attributes to the greater food intake of females. The ration was highest in June, especially for large individuals, although water temperature in June was lower than that in September. These results indicate that the amount of food intake is related to the annual life cycle of the marbled flounder.This work was partly supported by the Stock Assessment Program of Fisheries Agency and Fisheries Research and Education Agency of Japan and the program “Project on Clarifying the Impact of Nuclear Substances” of the Fisheries Agency of Japan

Utility of Nd isotope ratio as a tracer of marine animals : regional variation in coastal seas and causal factors

Isotopic compositions of animal tissue are an intrinsic marker commonly used to trace animal origins and migrations; however, few isotopes are effective for this purpose in marine environments, especially on a local scale. The isotope ratio of the lanthanoid element neodymium (Nd) is a promising tracer for coastal animal migrations. Neodymium derives from the same geologic materials as strontium, well known as an isotopic tracer (87Sr/86Sr) for terrestrial and anadromous animals. The advantage of the Nd isotope ratio (143Nd/144Nd, expressed as εNd) is that it varies greatly in the ocean according to the geology of the neighboring continents, whereas oceanic 87Sr/86Sr is highly uniform. This study explored the utility of the Nd isotope ratio as a marine tracer by investigating the variation of εNd preserved in tissues of coastal species, and the causes of that variation, in a region of northeastern Japan where the bedrock geology is highly variable. We measured εNd and 87Sr/86Sr in seawater, river water, and soft tissues of sedentary suspension feeders: the mussels Mytilus galloprovincialis and Mytilus coruscus and the oyster Crassostrea gigas. We also measured concentrations of three lanthanoids (La, Ce, and Pr) in shellfish bodies to determine whether the Nd in shellfish tissue was derived from solution in seawater or from suspended particulates. The εNd values in shellfish tissue varied regionally (−6 to +1), matching the ambient seawater, whereas all 87Sr/86Sr values were homogeneous and typical of seawater (0.7091–0.7092). The seawater εNd values were in turn correlated with those in the adjacent rivers, linking shellfish εNd to the geology of river catchments. The depletion of Ce compared to La and Pr (negative Ce anomaly) suggested that the Nd in shellfish was derived from the dissolved phase in seawater. Our results indicate that the distinct Nd isotope ratio derived from local geology is imprinted, through seawater, on the soft tissues of shellfish. This result underscores the potential of εNd as a tracer of coastal marine animals

Awareness of Complications of Dental Treatment in Patients Treated with Drugs Affecting the Immune System : A Nationwide Questionnaire Survey of Dental Practitioners in Japan

The aim of this study was to investigate the awareness and experience, among dental practitioners, of adverse events resulting from dental treatment of patients undergoing therapy with drugs that affect the immune system [angiogenesis inhibitors, biological agents, immunosuppressants, and disease-modifying anti-rheumatic drugs (DMARDs)]. For this purpose, a nationwide questionnaire survey was conducted. Questionnaires were sent to 2,050 dentists, of which 206 (10.1%) were completed and returned. The results showed that most dentists were aware of complications associated with dental treatment of patients treated with drugs that affect the immune system, and about half had actually experienced such complications. Delayed wound healing, osteonecrosis of the jaw (ONJ), and postoperative infections were reported. Whereas approximately 50% of dentists did not discontinue the drugs during dental treatment, about 18% did. During temporary drug discontinuation, some patients experienced aggravation of the primary disease, such as worsening of rheumatism, growth of tumors, and rejection reactions of transplanted organs. As for medical cooperation, only less than half of the dentists were asked for oral hygiene management by a physician prior to starting the drug treatment. Prospective studies are needed because evidence for dental treatments in patients treated with these drugs remains limited

Environmental stressors may cause unpredicted, notably lagged life-history responses in adults of the planktivorous Atlantic herring

Here we challenge traditional views on the direction of change in teleost body condition and reproductive traits in response to abiotic and biotic factors by studying the data-rich, planktivorous Norwegian spring-spawning herring (NSSH), a member of the abundant Atlantic herring (Clupea harengus) stock complex. To test potential influential factors, we focused on the last twenty years, i.e. a period with ocean warming, a transient but significant drop in zooplankton biomass, and accelerating interspecific competition resulting from primarily Atlantic mackerel (Scomber scombrus) entering these high-latitude waters in large quantities, “the new mackerel era” in the Nordic Seas. Adult NSSH concurrently allocated relatively less to growth in length than weight resulting in higher body condition. Growth likely decreased in warmer waters under stiff prey competition to support reproductive costs. Condition and reproductive responses were not only immediate but were also lagged by three seasons, corresponding to the period when new oocytes are produced. Furthermore, fecundity increased in warmer waters while egg size dropped. Hence, fine-tuned trade-off mechanisms were apparent and varied. We demonstrate that evaluations of reproductive trade-offs based on pooled data are misleading; poor- and good-condition NSSH followed different reproductive trajectories. These findings emphasize difficult-to-predict trends in life-history traits should be tracked longitudinally by the individuals and their aggregate cohort, as they are linked to complex overarching environmental phenomena, like ecosystem carrying capacity and climate fluctuations.publishedVersio

Neuroprotective effect of 5-aminolevulinic acid against low inorganic phosphate in neuroblastoma SH-SY5Y cells

PiT-1 (encoded by SLC20A1) and PiT-2 (encoded by SLC20A2) are type-III sodium-dependent phosphate cotransporters (NaPiTs). Recently, SLC20A2 mutations have been found in patients with idiopathic basal ganglia calcification (IBGC), and were predicted to bring about an inability to transport Pi from the extracellular environment. Here we investigated the effect of low Pi loading on the human neuroblastoma SH-SY5Y and the human glioblastoma A172 cell lines. The results show a different sensitivity to low Pi loading and differential regulation of type-III NaPiTs in these cells. We also examined whether 5-aminolevulinic acid (5-ALA) inhibited low Pi loading-induced neurotoxicity in SH-SY5Y cells. Concomitant application of 5-ALA with low Pi loading markedly attenuated low Pi-induced cell death and mitochondrial dysfunction via the induction of HO-1 by p38 MAPK. The findings provide us with novel viewpoints to understand the pathophysiology of IBGC, and give a new insight into the clinical prevention and treatment of IBGC

Identifying spawning events in the Japanese flounder Paralichthys olivaceus from depth time-series data

Vertical swimming events (VSEs) of the Japanese flounder, Paralichthys olivaceus, recorded by high-frequency depth data loggers, were analysed to identify spawning events. In total 25,907 VSEs from 10 adult fish were classified into 4 clusters using a k-means method. VSEs in a specific cluster (cluster-S) characterised by accelerated vertical swimming were identified as possible spawning events. Both the descent (0.43 ± 0.22 body length s− 1) and ascent rates (0.43 ± 0.24 body length s− 1) of VSEs in cluster-S were more than 4 times faster than in any other VSE. Our analyses indicated that 4 individuals exhibited the spawning events during the recording periods. The estimated spawning frequency ranged from 0.74 to 0.90 events day− 1. These values were comparable to those obtained in other field and laboratory studies. The spawning condition of fish at the time of recapture was confirmed by separate histological and anatomical observations, which supported the cluster analysis results. These results suggest that a clustering technique can be successfully applied to identify spawning behaviour from time-depth data of free-swimming flatfishes that exhibit vertical swimming movements