Showing papers by "Utsunomiya University published in 2022"

Uncovering the molecular mechanism for dual effect of ATP on phase separation in FUS solution

Abstract: Recent studies reported that adenosine triphosphate (ATP) could inhibit as well as enhance the phase separation in prion-like proteins. The molecular mechanism underlying such a puzzling phenomenon remains elusive. Here, taking the fused in sarcoma (FUS) solution as an example, we comprehensively reveal the underlying mechanism by which ATP regulates phase separation by combining the semiempirical quantum mechanical method, mean-field theory, and molecular simulation. At the microscopic level, ATP acts as a bivalent or trivalent binder; at the macroscopic level, the reentrant phase separation indeed occurs in dilute FUS solutions, resulting from the ATP-concentration--dependent binding ability under different conditions. Importantly, the ATP concentration for dissolving the protein condensates is about 10 mM, agreeing with experimental results. Furthermore, from a dynamic point of view, the effect of ATP on phase separation is also non-monotonic. This work provides a clear physical description of the microscopic interaction and macroscopic phase diagram of the ATP-modulated phase separation.

Review of thermal infrared polarimetry, I: theory

Abstract: We review the physics underlying thermal infrared emission, focusing on the processes that generate polarization. We also discuss a number of features of the theory that are not widely discussed in the literature, including the Straubel theorem for absorbing media, the mixed Poynting vector, and the emission of nonisothermal media. Using a model for emission from nonisothermal media, we present a quantitative discussion of the conditions under which Kirchhoff’s law is valid. Using this model, we show how it is possible for many blackbody simulators and infrared camera shutters to produce emission very close to true blackbodies.

Design of channeled spectropolarimeters

Abstract: I present design and tolerancing guidelines for constructing channeled spectropolarimeter systems employing high-order retarders. The discussion includes how to select appropriate retarder thicknesses, how to accurately align the elements, how to tolerance the retarders, and how to analyze the effect of different polarizer types on the system performance.

The feedback loop of the<i>transformer</i>gene results in proper feminization under multiple sex determination signals in the ant,<i>Vollenhovia emeryi</i>

Abstract: Abstract Organisms that reproduce sexually have evolved highly sophisticated mechanisms to generate two sexes. Some hymenopterans (such as ants, bees, and wasps) have a complementary sex-determination system in which heterozygosity at one CSD locus induces female development, whereas hemi- or homozygosity at the locus induces male development. This system can generate a high cost of inbreeding, as individuals that are homozygous at the locus become sterile, diploid males. On the other hand, some hymenopterans have evolved a multi-locus, complementary, sex-determination system in which heterozygosity in at least one CSD locus induces female development. This system effectively reduces the proportion of sterile diploid males; however, how multiple primary signals pass through a molecular cascade to regulate the terminal sex-determination gene has remained unclear. To clarify this matter, we investigated the molecular cascade in the ant, Vollenhovia emeryi , with two CSD loci. Here we show that transformer ( tra ) is necessary for proper feminization. Expression and functional analysis showed that individuals heterozygous in at least one of the two CSD loci develop into females. Individuals heterozygous at only a single CSD locus do not develop into sexual intermediates, because the signal derived from the heterozygous CSD is amplified by a positive-feedback splicing loop of tra . Our data also demonstrate that tra controls splicing of doublesex ( dsx ), which is involved in sexual differentiation. We suggest a cascade model to arrive at a binary determination of sex under multiple primary signals.

Study on Magnetic Abrasive Finishing Combined with Electrolytic Process–Precision Surface Finishing for SUS 304 Stainless Steel Using Pulse Voltage

Abstract: In order to further study the Magnetic Abrasive Finishing with Electrolytic (EMAF) Process, we attempted to use rectangular wave pulse voltage for EMAF processing of SUS304 stainless steel, and the finishing characteristics were analyzed based on the experimental results in this paper. The EMAF process has been studied for years, but the study of Magnetic Abrasive Finishing with the. Pulse Electrolytic (P-EMAF) process has not been published. Therefore, in this study, the finishing characteristics of the P-EMAF process corresponding to different frequencies (1 Hz, 10 Hz, 100 Hz, 1 kHz) and duty ratios (25%, 50%, 75%) are explored. The evaluation of the P-EMAF processing includes the surface roughness (SR) and the amount of material removal (MR); the surface of the workpiece was also observed by an optical microscope before and after processing. After analyzing the experimental results of P-EMAF processing, a set of comparative experiments between P-EMAF processing and MAF processing was carried out. In this study, when the Urms 6 V pulse voltage of rectangular wave with 1 Hz and duty ratio 50% was used, a better processing result could be obtained. The processing efficiency of the P-EMAF process was also higher than that of the MAF process under the same experimental conditions.

Evolutionarily conserved role of <i>hps1</i> in melanin production and blood coagulation in medaka fish

Abstract: Hermansky-Pudlak syndrome is an autosomal recessive disease characterized by albinism, visual impairment, and blood platelet dysfunction. One of the genes responsible for Hermansky-Pudlak syndrome, hps1, regulates organelle biogenesis and thus plays important roles in melanin production, blood clotting, and the other organelle-related functions in humans and mice. However, the function of hps1 in other species remains poorly understood. In this study, we discovered albino medaka fish during the maintenance of a wild-derived population and identified hps1 as the responsible gene using positional cloning. In addition to the specific absence of melanophore pigmentation, the hps1 mutant showed reduced blood coagulation, suggesting that hps1 is involved in clotting caused by both mammalian platelets and fish thrombocytes. Together, the findings of our study demonstrate that hps1 has an evolutionarily conserved role in melanin production and blood coagulation. In addition, our study presents a useful vertebrate model for understanding the molecular mechanisms of Hermansky-Pudlak syndrome.

Predominance of Cross-predation or Parallel-predation in Fish

Abstract: This chapter describes the effects of morphological antisymmetry and behavioral lateralization on predator-prey interactions in fishes. In fishes with morphological antisymmetry, predation events are defined as either cross-predation (the predator takes in prey of a different morphological type to itself) or parallel-predation (the predator takes in prey of the same morphological type as itself). Previous studies have demonstrated the predominance of cross-predation in some piscivorous fishes using stomach contents analysis. To understand the mechanism responsible for the predominance of cross-predation in fish communities, I conducted field sampling, stomach contents analysis, and behavioral experiments on largemouth bass and freshwater goby in a Japanese lake. Based on the results of behavioral experiments, I concluded that the predominance of cross-predation was caused by the lateral bias in the approach direction of bass and in the evasive distance of gobies according to their morphological type. Furthermore, I discussed the mechanism by which parallel-predation prevails and newly discovered it in the relationship between anglerfish and its prey species.

Review of thermal infrared polarimetry, part 2: experiment

Abstract: After the discussion on thermal polarization theory from part 1 of this review, we now review practical methods for experimentally measuring infrared polarization properties. Starting with a model for thermal emission from inhomogeneous media, we discuss the complexities of paints and how to determine the ideal thickness of paints used for blackbody simulators. Another commonly used inhomogeneous material is anodized aluminum, and we provide an extensive discussion of its fascinating structure and its optical properties in the thermal infrared. Theoretical analysis and experimental measurements show how the peculiar properties of alumina in the longwave infrared region combine to create a material that has a surprisingly high emissivity, for optically smooth sapphire and highly inhomogeneous anodize-coated aluminum. To illustrate features of thermal polarization theory given in part 1 of this review, we also present a series of infrared polarization images, and demonstrate the use of a convenient reference source for thermal polarization testing.