Mg/Ca micro-distribution in foraminiferal test: implication of laboratory culture experiments

Abstrac

Molecular characterization of bacteria and kleptoplast within Virgulinella fragilis

Abstrac

Chapter 2 Established and Emerging Techniques for Characterising the Formation, Structure and Performance of Calcified Structures under Ocean Acidification

Ocean acidification (OA) is the decline in seawater pH and saturation levels of calcium carbonate (CaCO3) minerals that has led to concerns for calcifying organisms such as corals, oysters and mussels because of the adverse effects of OA on their biomineralisation, shells and skeletons. A range of cellular biology, geochemistry and materials science approaches have been used to explore biomineralisation. These techniques have revealed that responses to seawater acidification can be highly variable among species, yet the underlying mechanisms remain largely unresolved. To assess the impacts of global OA, researchers will need to apply a range of tools developed across disciplines, many of which are emerging and have not yet been used in this context. This review outlines techniques that could be applied to study OA-induced alterations in the mechanisms of biomineralisation and their ultimate effects on shells and skeletons. We illustrate how to characterise, quantify and monitor the process of biomineralisation in the context of global climate change and OA. We highlight the basic principles, as well as the advantages and disadvantages, of established, emerging and future techniques for OA researchers. A combination of these techniques will enable a holistic approach and better understanding of the potential impact of OA on biomineralisation and its consequences for marine calcifiers and associated ecosystems

Benthic foraminiferal Mn / Ca ratios reflect microhabitat preferences

The Mn / Ca of calcium carbonate tests of living (rose-Bengal-stained) benthic foraminifera (Elphidium batialis, Uvigerina spp., Bolivina spissa, Nonionellina labradorica and Chilostomellina fimbriata) were determined in relation to pore water manganese (Mn) concentrations for the first time along a bottom water oxygen gradient across the continental slope along the NE Japan margin (western Pacific). The local bottom water oxygen (BWO) gradient differs from previous field study sites focusing on foraminiferal Mn / Ca and redox chemistry, therefore allowing further resolution of previously observed trends. The Mn / Ca ratios were analysed using laser ablation inductively coupled plasma-mass spectrometer (ICP-MS), allowing single-chamber determination of Mn / Ca. The incorporation of Mn into the carbonate tests reflects environmental conditions and is not influenced by ontogeny. The inter-species variability in Mn / Ca reflected foraminiferal in-sediment habitat preferences and associated pore water chemistry but also showed large interspecific differences in Mn partitioning. At each station, Mn / Ca ratios were always lower in the shallow infaunal E. batialis, occupying relatively oxygenated sediments, compared to intermediate infaunal species, Uvigerina spp. and B. spissa, which were typically found at greater depth, under more reducing conditions. The highest Mn / Ca was always recorded by the deep infaunal species N. labradorica and C. fimbriata. Our results suggest that although partitioning differs, Mn / Ca ratios in the intermediate infaunal taxa are promising tools for palaeoceanographic reconstructions as their microhabitat exposes them to higher variability in pore water Mn, thereby making them relatively sensitive recorders of redox conditions and/or bottom water oxygenation.Peer reviewe

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

Developments of deep-sea light and charge pump circuits fixed with an epoxy resin

海洋観測機器の製作コストやランニングコストを下げるため，プリント基板をエポキシ樹脂に直接固定し，水中や海 底で使用するLED光源とチャージポンプを開発，それぞれ耐圧試験や実海域での作動を確認した．LED光源は水深約 9200 mの海底に5回投入したが，物理的な破損もLEDの故障も生じなかった．この光源を基に製作したものをトンガ海 溝，ホライゾン海淵（水深10800 m）の海底で使用，堆積物直上の様子や底生生物活動のハイビジョン撮影に成功した． チャージポンプには圧力に弱い電解コンデンサが必要なため，樹脂で固定する前にコンデンサをカプセルで覆い，人工 的な気泡の中に配置することで圧力から保護する手法を開発した．この手法で樹脂固定して製作したチャージポンプと 赤色LEDを，伊平屋北熱水フィールド（水深1053 m）内の人工熱水噴出孔における深海電池の発電実験に供した．結 果，LEDの点灯により発電が確認された．エポキシ樹脂は海水，温度，圧力，光などによって劣化することが知られて いるが，深海環境における強度や透明度の変化についての知見はいまだ乏しいため，長期設置と強度試験による寿命の 推定が今後の課題となろう．A high power LED light and a charge pump with a LED indicator fixed with epoxy resin were developed in order to demonstrate reducing the cost of the deep-sea instruments. The LED light was brought at ca. 9200 m depth for five times. The light had no deformation and no crackes, and it worked after the deployents. It was also used to record the bottom at Tonga trench, where the world second deepest site (10800 m), and the video recording was succeeded. The charge pump was applied to confirm the electricity generation at the artificial hydrothermal vent in Iheya North hydrothermal field (1053 m). To protect electrolytic capacitors from pressure, they insulated from the resin with medicine capsules before fixing. The LED indicator was lighted on when the electrode of the fuel cell battery was inserted into the hydrothermal water. However, the degradation process of the epoxy resin under the deep-sea environments attributing high pressure and low temperature environments is still unknown. The guaranteed time of the instruments constructed with epoxy resin should be investigated throughout long term in situ exposure and the strength tests.http://www.godac.jamstec.go.jp/darwin/cruise/yokosuka/yk12-09/

A comparison between hospital follow‐up and collaborative follow‐up in patients with acute heart failure

AIMS: There are no previous studies focusing on collaborative follow-ups between hospitals and clinics for patients discharged after acute heart failure (AHF) in Japan. The purpose of this study was to determine the status of collaboration between hospitals and clinics for patients with AHF in Japan and to compare patient characteristics and clinical outcomes using a large Japanese observational database. METHODS AND RESULTS: Of 4056 consecutive patients hospitalized for AHF in the Kyoto Congestive Heart Failure registry, we analysed 2862 patients discharged to go home, who were divided into 1674 patients (58.5%) followed up at hospitals with index hospitalization (hospital follow-up group) and 1188 (41.5%) followed up in a collaborative fashion with clinics or other general hospitals (collaborative follow-up group). The primary outcome was a composite of all-cause death or heart failure (HF) hospitalization within 1 year after discharge. Previous hospitalization for HF and length of hospital stay longer than 15 days were associated with hospital follow-up. Conversely, ≥80 years of age, hypertension, and cognitive dysfunction were associated with collaborative follow-up. The cumulative 1-year incidence of the primary outcome, all cause death, and cardiovascular death were similar between the hospital and collaborative follow-up groups (31.6% vs. 29.6%, P = 0.51, 13.1% vs, 13.9%, P = 0.35, 8.4% vs. 8.2%, P = 0.96). Even after adjusting for confounders, the difference in risk for patients in the hospital follow-up group relative to those in the collaborative follow-up group remained insignificant for the primary outcome, all-cause death, and cardiovascular death (HR: 1.11, 95% CI: 0.97-1.27, P = 0.14, HR: 1.10, 95% CI: 0.91-1.33, P = 0.33, HR: 0.96, 95% CI: 0.87-1.05, P = 0.33). The cumulative 1-year incidence of HF hospitalization was higher in the hospital follow-up group than in the collaborative follow-up group (25.5% vs. 21.3%, P = 0.02). The risk of HF hospitalization was higher in the hospital follow-up group than in the collaborative follow-up group (HR: 1.19, 95% CI: 1.01-1.39, P = 0.04). CONCLUSIONS: In patients hospitalized for AHF, 41.5% received collaborative follow-up after discharge. The risk of HF hospitalization was higher in the hospital follow-up group than in the collaborative follow-up, although risk of the primary outcome, all-cause death, and cardiovascular death were similar between groups

Prognostic value of reduction in left atrial size during a follow-up of heart failure: an observational study

OBJECTIVE: The association between sequential changes in left atrial diameter (LAD) and prognosis in heart failure (HF) remains to be elucidated. The present study aimed to investigate the link between reduction in LAD and clinical outcomes in patients with HF. DESIGN: A multicentre prospective cohort study. SETTING: This study was nested from the Kyoto Congestive Heart Failure registry including consecutive patients admitted for acute decompensated heart failure (ADHF) in 19 hospitals throughout Japan. PARTICIPANTS: The current study population included 673 patients with HF who underwent both baseline and 6-month follow-up echocardiography with available paired LAD data. We divided them into two groups: the reduction in the LAD group (change <0 mm) (n=398) and the no-reduction in the LAD group (change ≥0 mm) (n=275). PRIMARY AND SECONDARY OUTCOMES: The primary outcome measure was a composite of all-cause death or hospitalisation for HF during 180 days after 6-month follow-up echocardiography. The secondary outcome measures were defined as the individual components of the primary composite outcome measure and a composite of cardiovascular death or hospitalisation for HF. RESULTS: The cumulative 180-day incidence of the primary outcome measure was significantly lower in the reduction in the LAD group than in the no-reduction in the LAD group (13.3% vs 22.2%, p=0.002). Even after adjusting 15 confounders, the lower risk of reduction in LAD relative to no-reduction in LAD for the primary outcome measure remained significant (HR 0.59, 95% CI 0.36 to 0.97 p=0.04). CONCLUSION: Patients with reduction in LAD during follow-up after ADHF hospitalisation had a lower risk for a composite endpoint of all-cause death or HF hospitalisation, suggesting that the change of LAD might be a simple and useful echocardiographic marker during follow-up

Improved and new-onset anemia during follow-up in patients with acute decompensated heart failure

There was no previous report on the prognostic impact of new-onset or improved anemia after discharge from acute decompensated heart failure (ADHF).We analyzed 771 patients with ADHF and who were followed in multicenters in Japan was divided into 4 groups based on the hemoglobin values at discharge and 6-month index visit: 373 patients (48.4%) with persistent anemia, 87 patients (11.3%) with new-onset anemia, 91 patients (11.8%) with improved anemia, and 220 patients (28.5%) without anemia.The primary outcome measure was a composite of all-cause death or HF hospitalization after index visit. The cumulative 6-month incidences of the primary outcome measure were 25.2% for persistent anemia, 18.5% for new onset anemia, 9.0% for improved anemia, and 9.2% for no anemia (log-rank P < .001). Compared with the no anemia group, the excess risk for the primary outcome measure remained significant in the persistent anemia group [hazard ratio (HR) 2.70, 95% confidence interval (95% CI), 1.45-5.44, P = .001] and in the new-onset anemia group (HR 2.73, 95% CI 1.19-6.25, P = .02), while it was not significant in the improved anemia group (HR 1.69, 95% CI 0.68-4.03, P = .25).Persistent and new-onset anemia at 6-month visit were associated with a subsequent higher risk for all-cause death or HF hospitalization in patients with ADHF, suggesting the importance of detecting anemia during follow-up

Risk Factors and Clinical Outcomes of Nonhome Discharge in Patients With Acute Decompensated Heart Failure: An Observational Study

Background: No clinical studies have focused on the factors associated with discharge destination in patients with acute decompensated heart failure. Methods and Results: Of 4056 consecutive patients hospitalized for acute decompensated heart failure in the KCHF (Kyoto Congestive Heart Failure) registry, we analyzed 3460 patients hospitalized from their homes and discharged alive. There were 3009 and 451 patients who were discharged to home and nonhome, respectively. We investigated the factors associated with nonhome discharge and compared the outcomes between home discharge and nonhome discharge. Factors independently and positively associated with nonhome discharge were age ≥80 years (odds ratio [OR], 1.76; 95% CI, 1.28–2.42), body mass index ≤22 kg/m2 (OR, 1.49; 95% CI, 1.12–1.97), poor medication adherence (OR, 2.08; 95% CI, 1.49–2.88), worsening heart failure (OR, 2.02; 95% CI, 1.46–2.82), stroke during hospitalization (OR, 3.74; 95% CI, 1.75–8.00), functional decline (OR, 12.24; 95% CI, 8.74–17.14), and length of hospital stay >16 days (OR, 4.14; 95% CI, 3.01–5.69), while those negatively associated were diabetes mellitus (OR, 0.69; 95% CI, 0.51–0.94), cohabitants (OR, 0.62; 95% CI, 0.46–0.85), and ambulatory state before admission (OR, 0.25; 95% CI, 0.18–0.36). The cumulative 1‐year incidence of all‐cause death was significantly higher in the nonhome discharge group than in the home discharge group. The nonhome discharge group compared with the nonhome discharge group was associated with a higher adjusted risk for all‐cause death (hazard ratio, 1.66; P<0.001). Conclusions: The discharge destination of patients with acute decompensated heart failure is influenced by factors such as prehospital social background, age, body mass index, low self‐care ability, events during hospitalization (worsening heart failure, stroke, etc), functional decline, and length of hospital stay; moreover, the prognosis of nonhome discharge patients is worse than that of home discharge patients. Registration Information: clinicaltrials.gov. Identifier: NCT02334891