Major contribution of sulfide‐derived sulfur to the benthic food web in a large freshwater lake

In freshwater systems, contributions of chemosynthetic products by sulfur-oxidizing bacteria in sediments as nutritional resources in benthic food webs remain unclear, even though chemosynthetic products might be an important nutritional resource for benthic food webs in deep-sea hydrothermal vents and shallow marine systems. To study geochemical aspects of this trophic pathway, we sampled sediment cores and benthic animals at two sites (90 and 50 m water depths) in the largest freshwater (mesotrophic) lake in Japan: Lake Biwa. Stable carbon, nitrogen, and sulfur isotopes of the sediments and animals were measured to elucidate the sulfur nutritional resources for the benthic food web precisely by calculating the contributions of the incorporation of sulfide-derived sulfur to the biomass and of the biogeochemical sulfur cycle supporting the sulfur nutritional resource. The recovered sediment cores showed increases in ³⁴S-depleted sulfide at 5 cm sediment depth and showed low sulfide concentration with high δ³⁴S in deeper layers, suggesting an association of microbial activities with sulfate reduction and sulfide oxidation in the sediments. The sulfur-oxidizing bacteria may contribute to benthic animal biomass. Calculations based on the biomass, sulfur content, and contribution to sulfide-derived sulfur of each animal comprising the benthic food web revealed that 58%–67% of the total biomass sulfur in the benthic food web of Lake Biwa is occupied by sulfide-derived sulfur. Such a large contribution implies that the chemosynthetic products of sulfur-oxidizing bacteria are important nutritional resources supporting benthic food webs in the lake ecosystems, at least in terms of sulfur. The results present a new trophic pathway for sulfur that has been overlooked in lake ecosystems with low-sulfate concentrations

〈研究論文〉明治30年代における教師の修養 : 雑誌『日本之小學教師』を手がかりに

The purpose of this research is to examine the teachers’ “Syuuyo” theory from the Meiji 30’s period through a comparison with general Syuuyo theory, through an analysis of “Nihon no Syougaku Kyoushi.”The objectives of the study are (1) to understand the semantic content of the general Syuuyo theory, (2) to understand the semantic content of the teachers’ “Syuuyo” theory, (3) to consider the teachers’ “Syuuyo” theory at the earliest stage based on (1) and (2).Meiji era Japan, being forced to modernize, was also under pressure to seek different self-formation concepts. The general Syuuyo theory was born as a concept to respond to these circumstances. The theory was born as a translation for “cultivate.”The general Syuuyo theory aimed at improving character and reflecting on the premise of endogenous motives.On the other hand, Teachers’ “Syuuyo” appeared against the backdrop of the collapse in social order. The word “Syuuyo” was practiced with the aim of acquiring an“enlightenment force” to develop a forward-looking nation. To acquire this “enlightenment force,” teachers were required not only to teach in the oral tradition but also demonstrate through their actions “knowledge, moral principles, and physical health” of all related matterseducated and ingrained in elementary schools as well as through guidance in aspects of daily life. Whereas the general Syuuyo theory aimed to refine self-spirit based on endogenous motives, the first teachers’ ‘Syuuyo’ of the Meiji 30’s period was not based on intrinsic motives of teachers. Teacher’s “Syuuyo”theory at the earliest time was able to acquire an “enlightenment force” by practicing various matters related to education and imparting through their actions “knowledge, moral principles and physical health” as well as guidance in aspects of daily life

Small sensor probe for measuring plasma waves in space Space science

Background: Since conventional one-point observations of plasma phenomena in space cannot distinguish between time and spatial variations, the missions on the basis of multiple-point observations have become the trend. We propose a new system for multiple-point observation referred to as the monitor system for space electromagnetic environments (MSEE). Findings: The MSEE consists of small sensor probes that have a capability to measure electromagnetic waves and transfer received data to the central station through wireless communication. We developed the prototype model of the MSEE sensor probe. The sensor probe includes a plasma wave receiver, the microcontroller, the wireless communication module, and the battery in the 75-mm cubic housing. In addition, loop antennas, dipole antennas, and actuators that are used for expanding dipole antennas are attached on the housing. The whole mass of the sensor probe is 692 g, and the total power consumption is 462 mW. The sensor probe can work with both inner battery and external power supply. The maximum continuous operation time on battery power is more than 6 h. We verified the total performance for electric field measurements by inputting signal to preamplifier. In this test, we found that analog components had enough characteristics to measure electric fields, and the A/D conversion and the wireless transmission worked correctly. In the whole performance for electric fields, the sensor probe has equivalent noise level of - 135 dBV/m/√Hz. Conclusions: We succeed in developing the prototype model of the small sensor probe that had enough sensitivity for electric field to measure plasma waves and the ability to transfer observation data through wireless communication. The success in developing the small sensor probe for the measurement of plasma waves leads to the realization of the multiple-point observations using a lot of small probes scattered in space

NO Reduction Cycle on Dinuclear Ruthenium Complexes having Hydrotris(pyrazolyl)borato

ナノダイナミクス国際シンポジウム 平成22年1月21日(木) 於長崎大学Nagasaki Symposium on Nano-Dynamics 2010 (NSND2010), January 21, 2010, Nagasaki University, Nagasaki, Japan, Invited Lectur

Physiological Properties of Rod Photoreceptor Cells in Green-sensitive Cone Pigment Knock-in Mice

Rod and cone photoreceptor cells that are responsible for scotopic and photopic vision, respectively, exhibit photoresponses different from each other and contain similar phototransduction proteins with distinctive molecular properties. To investigate the contribution of the different molecular properties of visual pigments to the responses of the photoreceptor cells, we have generated knock-in mice in which rod visual pigment (rhodopsin) was replaced with mouse green-sensitive cone visual pigment (mouse green). The mouse green was successfully transported to the rod outer segments, though the expression of mouse green in homozygous retina was ∼11% of rhodopsin in wild-type retina. Single-cell recordings of wild-type and homozygous rods suggested that the flash sensitivity and the single-photon responses from mouse green were three to fourfold lower than those from rhodopsin after correction for the differences in cell volume and levels of several signal transduction proteins. Subsequent measurements using heterozygous rods expressing both mouse green and rhodopsin E122Q mutant, where these pigments in the same rod cells can be selectively irradiated due to their distinctive absorption maxima, clearly showed that the photoresponse of mouse green was threefold lower than that of rhodopsin. Noise analysis indicated that the rate of thermal activations of mouse green was 1.7 × 10−7 s−1, about 860-fold higher than that of rhodopsin. The increase in thermal activation of mouse green relative to that of rhodopsin results in only 4% reduction of rod photosensitivity for bright lights, but would instead be expected to severely affect the visual threshold under dim-light conditions. Therefore, the abilities of rhodopsin to generate a large single photon response and to retain high thermal stability in darkness are factors that have been necessary for the evolution of scotopic vision

mtDNA diversity of the Zapotec in Mexico suggests a population decline long before the first contact with Europeans.

The New World is the last continent colonized by anatomically modern humans, Homo sapiens. The first migrants entered the New World from Asia through Beringia. It is suggested that there were three streams of Asian gene flow, one major and two additional minor gene flows. The first major migrants took a Pacific coastal route and began spreading to the American continent before the opening of the ice-free corridor. We investigated the diversity of full-length mitochondrial DNA genomes of the Zapotec population, residing in the Mesoamerican region, and reconstructed their demographic history using Bayesian Skyline Plots. We estimated the initial date of gene flow into the New World by Zapotec ancestors at around 17 000–19 000 years ago,which is highly concordant with previous studies. We also show a population decline after the initial expansion. This decline started 4000 years ago, long before European contact with Native Americans. This indicates that other factors including climatec hange should be considered to explain the observed demographic pattern

Methylation of a nitrosylruthenium complex bearing a hydridotris(pyrazolyl)borate ligand

Reaction of [TpRuCl2(NO)] (1) (Tp = HB(pyrazol-1-yl) 3) with dimethylzinc, Zn(Me)2, gave rise to a dimethyl complex [TpRu(Me)2(NO)] (2) and a monomethyl complex [TpRuCl(Me)(NO)] (3) in good yields, while the use of a Grignard reagent, MeMgCl, as the alkylating agents led to isolation of 2 in low yield. Complexes 2 and 3 were confirmed by single-crystal X-ray diffraction analyses. Treatment of 2 with triflic acid, CF3SO3H, afforded a triflato complex [TpRu(Me){OS(O)2CF3}(NO)] (4)