Intracellular isotope localization in Ammonia sp. (Foraminifera) of oxygen-depleted environments : results of nitrate and sulfate labeling experiments

© The Author(s), 2016. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Frontiers in Microbiology 7 (2016): 163, doi:10.3389/fmicb.2016.00163.Some benthic foraminiferal species are reportedly capable of nitrate storage and denitrification, however, little is known about nitrate incorporation and subsequent utilization of nitrate within their cell. In this study, we investigated where and how much 15N or 34S were assimilated into foraminiferal cells or possible endobionts after incubation with isotopically labeled nitrate and sulfate in dysoxic or anoxic conditions. After 2 weeks of incubation, foraminiferal specimens were fixed and prepared for Transmission Electron Microscopy (TEM) and correlative nanometer-scale secondary ion mass spectrometry (NanoSIMS) analyses. TEM observations revealed that there were characteristic ultrastructural features typically near the cell periphery in the youngest two or three chambers of the foraminifera exposed to anoxic conditions. These structures, which are electron dense and ~200–500 nm in diameter and co-occurred with possible endobionts, were labeled with 15N originated from 15N-labeled nitrate under anoxia and were labeled with both 15N and 34S under dysoxia. The labeling with 15N was more apparent in specimens from the dysoxic incubation, suggesting higher foraminiferal activity or increased availability of the label during exposure to oxygen depletion than to anoxia. Our results suggest that the electron dense bodies in Ammonia sp. play a significant role in nitrate incorporation and/or subsequent nitrogen assimilation during exposure to dysoxic to anoxic conditions.This work was supported by a Grant-in-Aid for Scientific Research from the Ministry of Education, Culture, Sports, Science and Technology, Japan (Young Scientists B No. 22740340 and Scientific Research C No. 24540504 to HN), an Invitation Fellowship for Research in Japan to JB by Japan Society for the Promotion of Science (JSPS), the Robert W. Morse Chair for Excellence in Oceanography at WHOI to JB, and The Investment in Science Fund at WHOI to JB

Learning-Dependent Gene Expression of CREB1 Isoforms in the Molluscan Brain

Cyclic AMP-responsive element binding protein1 (CREB1) has multiple functions in gene regulation. Various studies have reported that CREB1-dependent gene induction is necessary for memory formation and long-lasting behavioral changes in both vertebrates and invertebrates. In the present study, we characterized Lymnaea CREB1 (LymCREB1) mRNA isoforms of spliced variants in the central nervous system (CNS) of the pond snail Lymnaea stagnalis. Among these spliced variants, the three isoforms that code a whole LymCREB1 protein are considered to be the activators for gene regulation. The other four isoforms, which code truncated LymCREB1 proteins with no kinase inducible domain, are the repressors. For a better understanding of the possible roles of different LymCREB1 isoforms, the expression level of these isoform mRNAs was investigated by a real-time quantitative RT-PCR method. Further, we examined the changes in gene expression for all the isoforms in the CNS after conditioned taste aversion (CTA) learning or backward conditioning as a control. The results showed that CTA learning increased LymCREB1 gene expression, but it did not change the activator/repressor ratio. Our findings showed that the repressor isoforms, as well as the activator ones, are expressed in large amounts in the CNS, and the gene expression of CREB1 isoforms appeared to be specific for the given stimulus. This was the first quantitative analysis of the expression patterns of CREB1 isoforms at the mRNA level and their association with learning behavior

Subretinal Hemorrhage after Photodynamic Therapy for Juxtapapillary Retinal Capillary Hemangioma

A 75-year-old Japanese woman presented with a juxtapapillary retinal capillary hemangioma (RCH) in her left eye. Twelve months after the initial examination, the size of the hemangioma had increased and the exudation from the RCH involved the macula. Her best-corrected visual acuity (BCVA) had decreased from 0.8 to 0.3. A total of five intravitreal injections of bevacizumab (IVB; 1.25 mg) was given but the RCH did not respond. A photodynamic therapy (PDT) was done using multiple laser spots to avoid damaging the optic nerve head. After the first PDT, the subfoveal fluid was reduced but not completely gone. One week after the second PDT, a massive subretinal hemorrhage developed. The subretinal hemorrhage was successfully displaced by injecting intraocular sulfur hexafluoride (SF6) gas. At the 3-year follow-up examination, no subretinal hemorrhage or fluid was observed at the macula and the BCVA remained at 0.05. Our case was resistant to the combination of anti-vascular endothelial growth factor (VEGF) and PDT and had a rare massive subretinal hemorrhage. A further collection of RCH cases treated with anti-VEGF and PDT that would justify this treatment is necessary

Photoperiodic Modulation of Circadian Clock and Reproductive Axis Gene Expression in the Pre-Pubertal European Sea Bass Brain

The acquisition of reproductive competence requires the activation of the brain-pituitary-gonad (BPG) axis, which in most vertebrates, including fishes, is initiated by changes in photoperiod. In the European sea bass long-term exposure to continuous light (LL) alters the rhythm of reproductive hormones, delays spermatogenesis and reduces the incidence of precocious males. In contrast, an early shift from long to short photoperiod (AP) accelerates spermatogenesis. However, how photoperiod affects key genes in the brain to trigger the onset of puberty is still largely unknown. Here, we investigated if the integration of the light stimulus by clock proteins is sufficient to activate key genes that trigger the BPG axis in the European sea bass. We found that the clock genes clock, npas2, bmal1 and the BPG genes gnrh, kiss and kissr share conserved transcription factor frameworks in their promoters, suggesting co-regulation. Other gene promoters of the BGP axis were also predicted to be co-regulated by the same frameworks. Co-regulation was confirmed through gene expression analysis of brains from males exposed to LL or AP photoperiod compared to natural conditions: LL fish had suppressed gnrh1, kiss2, galr1b and esr1, while AP fish had stimulated npas2, gnrh1, gnrh2, kiss2, kiss1rb and galr1b compared to NP. It is concluded that fish exposed to different photoperiods present significant expression differences in some clock and reproductive axis related genes well before the first detectable endocrine and morphological responses of the BPG axis.European Community [222719 - LIFECYCLE]; Foundation for Science and Technology of Portugal (FCT) [SFRH/BPD/66742/2009, PEst-C/MAR/LA0015/2011]; Valencian Regional Goverment [Prometeo II/2014/051]; Spanish Ministry of Science and Innovation (MICINN) [CSD 2007-0002]info:eu-repo/semantics/publishedVersio

Diagnosis of infections in newborns using a new particle-mediated immunoassay for serum C-reactive protein

C-reactive protein (CRP) levels were measured using a new particle-mediated immunoassay. Tests for precision and linearity of this method gave satisfactory results. The minimum sensitivity of the assay was 1 ng/ml. Interference by bilirubin (<220mg/l) and haemoglobin (<20g/l) was not observed. Using this method, CRP was assayed as a means of monitoring for infection in newborns up to 72 h after delivery. The pattern of time course elevation curves was similar for both groups (10 healthy subjects and 26 patients), but the serum CRP (ng/ml) of infected newborns rose significantly higher than in healthy subjects at 24 h after birth. The rate of increase of CRP (∆CRP; ng/ml/h) may be a more useful parameter to detect infection, since a significant change in ∆CRP was apparent only 12 h after birth. The reported method was reliable and the parameters obtained were considered clinically useful for early detection of infection

Rapid detection and quantification of Nile Red-stained microplastic particles in sediment samples

The distribution and migration processes of microplastics (MPs) in the marine sediments have yet to be fully elucidated. To estimate the contamination levels and distribution patterns, and develop countermeasures, the amount of MPs must be understood. Rapid and efficient processing of numerous samples is also needed to detect and determine MP contamination. However, whatever the sample of interest, MP analysis is time consuming. This is especially the case for deep-sea sediments, where the particle sizes are small and pretreatment processes are complex and time-consuming. To address the need for rapid and efficient detection of MPs, we propose a novel method for automatically identifying and counting Nile Red (NR)-stained sedimentary MP particles captured under a stereoscopic fluorescence microscope. In this study, we demonstrated the utility of the developed system by comparing its recovery rate and analysis time with those of the conventional methods used for manual processing. The developed method can efficiently detect MPs of sizes between 18 and 500 µm and classify them as fibers or grains (or fragments). This means that our method can efficiently detect MPs as small as 100 µm found in deep-sea sediments. The semi-automated MP detection system gave a counting time of 4.2–8.8 s per particle—as the number of particles increases, the analysis time per particle decreases. Similarly, when the number of particles counted using a stereomicroscope and image analysis software was set at 100, the automatic measurement method using a flow cell could measure 50−80% of the total number of particles, depending on the type of MPs. By using artificial particulate and fibrous MPs as training data and combining them with a machine learning system, we were able to build a system that can classify both types with 98% accuracy (100% for fibers and 96% for grains). In natural samples, approximately 150 µm (20–350 µm in range) MPs were detected, and the number was consistent with previous studies. This demonstrates the effectiveness of the method we developed. We established a rapid detection method for the number and form of MPs using a continuous semi-automated method, combining NR staining and artificial intelligence. Although this method does not allow the identification of polymer types, it enables that rapid and reliable quantification of MPs numbers. The new method established in this study is expected to improve the accuracy of information on the distribution, destination, and quantity of MPs. It is also relatively easy to use and can transfer technology in various fields, from citizen science to rapid diagnosis on research vessels in the open ocean.</p

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高校生年代のサッカー選手がプロサッカー選手になるために必要な心理的能力および心理的特性に関する質的研究

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