Nutritional sources of meio- and macrofauna at hydrothermal vents and adjacent areas: Natural-abundance radiocarbon and stable isotope analyses

© The Author(s), 2019. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Nomaki, H., Uejima, Y., Ogawa, N. O., Yamane, M., Watanabe, H. K., Senokuchi, R., Bernhard, J. M., Kitahashi, T., Miyairi, Y., Yokoyama, Y., Ohkouchi, N., & Shimanaga, M. Nutritional sources of meio- and macrofauna at hydrothermal vents and adjacent areas: Natural-abundance radiocarbon and stable isotope analyses. Marine Ecology Progress Series, 622, (2019): 49-65, doi:10.3354/meps13053.Deep-sea hydrothermal vents host unique marine ecosystems that rely on organic matter produced by chemoautotrophic microbes together with phytodetritus. Although meiofauna can be abundant at such vents, the small size of meiofauna limits studies on nutritional sources. Here we investigated dietary sources of meio- and macrofauna at hydrothermal vent fields in the western North Pacific using stable carbon and nitrogen isotope ratios (δ13C, δ15N) and natural-abundance radiocarbon (Δ14C). Bacterial mats and Paralvinella spp. (polychaetes) collected from hydrothermal vent chimneys were enriched in 13C (up to -10‰) and depleted in 14C (-700 to -580‰). The δ13C and Δ14C values of dirivultid copepods, endemic to hydrothermal vent chimneys, were -11‰ and -661‰, respectively, and were similar to the values in the bacterial mats and Paralvinella spp. but distinct from those of nearby non-vent sediments (δ13C: ~-24‰) and water-column plankton (Δ14C: ~40‰). In contrast, δ13C values of nematodes from vent chimneys were similar to those of non-vent sites (ca. -25‰). Results suggest that dirivultids relied on vent chimney bacterial mats as their nutritional source, whereas vent nematodes did not obtain significant nutrient amounts from the chemolithoautotrophic microbes. The Δ14C values of Neoverruca intermedia (vent barnacle) suggest they gain nutrition from chemoautotrophic microbes, but the source of inorganic carbon was diluted with bottom water much more than those of the Paralvinella habitat, reflecting Neoverruca’s more distant distribution from active venting. The combination of stable and radioisotope analyses on hydrothermal vent organisms provides valuable information on their nutritional sources and, hence, their adaptive ecology to chemosynthesis-based ecosystems.We are grateful to the crews and scientists of the R/V ‘Natsushima’ and the ROV ‘Hyper-Dolphin’ of the Japan Agency for Marine-Earth Science and Technology (JAMSTEC) during the NT12-10, NT13-09 and NT14-06 cruises, and the R/V ‘Kaimei’ and the KM-ROV of JAMSTEC during the KM-ROV training cruise. We thank Yuki Iwadate for her help on sample preparations and 2 anonymous reviewers and the editor, who provided helpful comments on an earlier version of this manuscript. This work was supported by a Grant-in-Aid for Scientific Research from the Ministry of Education, Culture, Sports, Science and Technology, Japan (Scientific Research C 26440246 to M.S.), the Japan Society for the Promotion of Science (Invitational fellowships for research in Japan, S14032 to J.M.B.), the WHOI Robert W. Morse Chair for Excellence in Oceanography, and The Investment in Science Fund at WHOI

Gastrointestinal-Sparing Effects of Novel NSAIDs in Rats with Compromised Mucosal Defence

Nonsteroidal anti-inflammatory drugs are among the most commonly used prescription and over-the-counter medications, but they often produce significant gastrointestinal ulceration and bleeding, particularly in elderly patients and patients with certain co-morbidities. Novel anti-inflammatory drugs are seldom tested in animal models that mimic the high risk human users, leading to an underestimate of the true toxicity of the drugs. In the present study we examined the effects of two novel NSAIDs and two commonly used NSAIDs in models in which mucosal defence was expected to be impaired. Naproxen, celecoxib, ATB-346 (a hydrogen sulfide- and naproxen-releasing compound) and NCX 429 (a nitric oxide- and naproxen-releasing compound) were evaluated in healthy, arthritic, obese, and hypertensive rats and in rats of advanced age (19 months) and rats co-administered low-dose aspirin and/or omeprazole. In all models except hypertension, greater gastric and/or intestinal damage was observed when naproxen was administered in these models than in healthy rats. Celecoxib-induced damage was significantly increased when co-administered with low-dose aspirin and/or omeprazole. In contrast, ATB-346 and NCX 429, when tested at doses that were as effective as naproxen and celecoxib in reducing inflammation and inhibiting cyclooxygenase activity, did not produce significant gastric or intestinal damage in any of the models. These results demonstrate that animal models of human co-morbidities display the same increased susceptibility to NSAID-induced gastrointestinal damage as observed in humans. Moreover, two novel NSAIDs that release mediators of mucosal defence (hydrogen sulfide and nitric oxide) do not induce significant gastrointestinal damage in these models of impaired mucosal defence

Erratum to: 36th International Symposium on Intensive Care and Emergency Medicine

[This corrects the article DOI: 10.1186/s13054-016-1208-6.]

Diffusion Monte Carlo Study of Para -Diiodobenzene Polymorphism Revisited

We revisit our investigation of the diffusion Monte Carlo (DMC) simulation of p-DIB molecular crystal polymorphism. [J. Phys. Chem. Lett. 2010, 1, 1789-1794] We perform, for the first time, a rigorous study of finite-size effects and choice of nodal surface on the prediction of polymorph stability in molecular crystals using fixed-node DMC. Our calculations are the largest which are currently feasible using the resources of the K computer and provide insights into the formidable challenge of predicting such properties from first principles. In particular, we show that finite-size effects can influence the trial nodal surface of a small (1×1×1) simulation cell considerably. We therefore repeated our DMC simulations with a 1×3×3 simulation cell, which is the largest such calculation to date. We used a DFT nodal surface generated with the PBE functional and we accumulated statistical samples with ∼6.4×105 core-hours for each polymorph. Our final results predict a polymorph stability consistent with experiment, but indicate that results in our previous paper were somewhat fortuitous. We analyze the finite-size errors using model periodic Coulomb (MPC) interactions and kinetic energy corrections, according to the CCMH scheme of Chiesa, Ceperley, Martin, and Holzmann. We investigate the dependence of the finite-size errors on different aspect ratios of the simulation cell (k-mesh convergence) in order to understand how to choose an appropriate ratio for the DMC calculations. Even in the most expensive simulations currently possible, we show that the finite size errors in the DMC total energies are far larger than the energy difference between the two polymorphs, although error cancellation means that the polymorph prediction is accurate. Finally, we found that the T-move scheme is essential for these massive DMC simulations in order to circumvent population explosions and large time-step biases.Chemistry and Chemical Biolog