384 research outputs found

    A new species of Cybaeus with short genitalia from central Honshu, Japan (Araneae: Cybaeidae)

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    Spiders of the genus Cybaeus are diverse in Japan and exhibit extensive morphological variation of their genitalia among species. Among Japanese Cybaeus, several species possess an elongated embolus in males and elongated spermathecae in females. Here, we describe Cybaeus iharai sp. nov. from Nagano Prefecture, central Honshu, Japan, which possesses a short embolus in males and short copulatory ducts in females. In addition, DNA sequences of the new species were obtained for future phylogenetic analyses

    Integrative taxonomy reveals multiple lineages of the spider genus Cybaeus endemic to the Ryukyu Islands, Japan (Arachnida : Araneae : Cybaeidae)

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    The epigean spiders of the genus Cybaeus L. Koch, 1868 are known to have diversified in western North America and the Japanese Archipelago. To date, ~80 species of Cybaeus are known from Japan, but they have not previously been recorded from the Ryukyu Islands that harbour a diversity of endemic species. Here we describe eight new species of Cybaeus from the Ryukyu Islands, extending the range of Cybaeus southward to the central Ryukyus. Both sexes of each of the new species are described, and their phylogenetic relationships are estimated using nuclear and mitochondrial gene markers. Although Cybaeus okumurai, sp. nov. and C. kumadori, sp. nov. possess genital features that are common in the other Japanese congeners, the other six species (C. yakushimensis, sp. nov., C. kodama, sp. nov., C. amamiensis, sp. nov., C. aikana, sp. nov., C. tokunoshimensis, sp. nov., and C. hikidai, sp. nov.) are characterised by an elongated embolus and tubular spermathecae. These unique genital characteristics and the phylogeny recovered here suggest that these features evolved independently among the Japanese and Ryukyu Cybaeus species. Phylogenetic analyses highlight an unusual biogeographical pattern in which C. yakushimensis and C. kodama endemic to Yakushima Island in the northern Ryukyus are related to species distributed in the central Ryukyus. In contrast, our phylogeny suggests that C. okumurai from Tanegashima Island in the northern Ryukyus is sister to C. ashikitaensis (Komatsu, 1968), distributed in Kyushu of the Japanese Archipelago. The retreat constructs and sympatric distribution of Cybaeus found among the Ryukyus are also briefly discussed

    Development of a yeast cell surface display method using the SpyTag/SpyCatcher system

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    生体内タンパク質ライゲーションを用いた新規細胞表層ディスプレイ法の開発 --新しい手法によるタンパク質工学の進展--. 京都大学プレスリリース. 2021-05-28.Yeast cell surface display (YSD) has been used to engineer various proteins, including antibodies. Directed evolution, which subjects a gene to iterative rounds of mutagenesis, selection and amplification, is useful for protein engineering. In vivo continuous mutagenesis, which continuously diversifies target genes in the host cell, is a promising tool for accelerating directed evolution. However, combining in vivo continuous evolution and YSD is difficult because mutations in the gene encoding the anchor proteins may inhibit the display of target proteins on the cell surface. In this study, we have developed a modified YSD method that utilises SpyTag/SpyCatcher-based in vivo protein ligation. A nanobody fused with a SpyTag of 16 amino acids and an anchor protein fused with a SpyCatcher of 113 amino acids are encoded by separate gene cassettes and then assembled via isopeptide bond formation. This system achieved a high display efficiency of more than 90%, no intercellular protein ligation events, and the enrichment of target cells by cell sorting. These results suggested that our system demonstrates comparable performance with conventional YSD methods; therefore, it can be an appropriate platform to be integrated with in vivo continuous evolution

    Object affordance as a guide for grasp-type recognition

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    Recognizing human grasping strategies is an important factor in robot teaching as these strategies contain the implicit knowledge necessary to perform a series of manipulations smoothly. This study analyzed the effects of object affordance-a prior distribution of grasp types for each object-on convolutional neural network (CNN)-based grasp-type recognition. To this end, we created datasets of first-person grasping-hand images labeled with grasp types and object names, and tested a recognition pipeline leveraging object affordance. We evaluated scenarios with real and illusory objects to be grasped, to consider a teaching condition in mixed reality where the lack of visual object information can make the CNN recognition challenging. The results show that object affordance guided the CNN in both scenarios, increasing the accuracy by 1) excluding unlikely grasp types from the candidates and 2) enhancing likely grasp types. In addition, the "enhancing effect" was more pronounced with high degrees of grasp-type heterogeneity. These results indicate the effectiveness of object affordance for guiding grasp-type recognition in robot teaching applications.Comment: 12 pages, 11 figures. Last updated February 27th, 202

    Thermal Conductivity in the Bose-Einstein Condensed State of Triplons in the Bond-Alternating Spin-Chain System Pb2V3O9

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    In order to clarify the origin of the enhancement of the thermal conductivity in the Bose-Einstein Condensed (BEC) state of field-induced triplons, we have measured the thermal conductivity along the [101] direction parallel to spin-chains, kappa[101]kappa_{\|[101]}, and perpendicular to spin-chains, kappa[101]kappa_{\perp[101]}, of the S=1/2 bond-alternating spin-chain system Pb2V3O9 in magnetic fields up to 14 T. With increasing field at 3 K, it has been found that both kappa[101]kappa_{\|[101]} and kappa[101]kappa_{\perp[101]} are suppressed in the gapped normal state in low fields. In the BEC state of field-induced triplons in high fields, on the other hand, kappa[101]kappa_{\|[101]} is enhanced with increasing field, while kappa[101]kappa_{\perp[101]} is suppressed. That is, the thermal conductivity along the direction, where the magnetic interaction is strong, is markedly enhanced in the BEC state. Accordingly, our results suggest that the enhancement of kappa[101]kappa_{\|[101]} in the BEC state is caused by the enhancement of the thermal conductivity due to triplons on the basis of the two-fluid model, as in the case of the superfluid state of liquid 4He.Comment: 5 pages, 3 figure

    A transcription frame-based analysis of the genomic DNA sequence of a hyper-thermophilic archaeon for the identification of genes, pseudo-genes and operon structures

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    AbstractAn algorithm for identifying transcription units, independently regulated genes and operons, and pseudo-genes that are not expected to be expressed, has been developed by combining a system for predicting transcription and translation signals, and a system for scoring the triplet periodicity in ORF candidates. By using the algorithm, the 1.09 Mb sequence that covers approximately 60% of the genome of Pyrococcus sp. OT3 has been analyzed. The identified ORFs show the expected biological and physical characteristics, while the rejected ORF candidates do not. Frequent use of operon structures for transcription, and gene duplication followed by mutation or termination of the duplicated genes, are discussed

    A Case of Severe Esophageal Intramural Pseudodiverticulosis Whose Symptoms Were Ameliorated by Oral Administration of Anti-Fungal Medicine

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    Esophageal intramural pseudodiverticulosis (EIPD) is a rare disease of unknown etiology that displays multiple pseudodiverticula radiologically, leading to benign esophageal stricture. Dysphagia, which sometimes slowly progresses, is the main symptom in the majority of cases. We here report a 59-year-old male EIPD patient who suffered from severe dysphagia. Radiography and endoscopy of this patient disclosed a severe constriction in the upper thoracic esophagus. Although we tried several endoscopic procedures including frequent endoscopic balloon dilatation (EBD), the effect was very limited and his dysphagia relapsed shortly after the treatments. During the procedures, we noticed some white, thick, creamy liquid emerging from the orifices of EIPD, and PAS staining of biopsy specimens revealed infection with Candida albicans. Hence, the patient was given anti-fungal medicine in addition to EBD. The additional treatment with anti-fungal medicine dramatically improved his symptoms and the esophageal constriction. This case suggests that anti-fungal treatment is an effective first-line therapy even against a severe form of esophageal constriction in EIPD

    Constraint-aware Policy for Compliant Manipulation

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    Robot manipulation in a physically-constrained environment requires compliant manipulation. Compliant manipulation is a manipulation skill to adjust hand motion based on the force imposed by the environment. Recently, reinforcement learning (RL) has been applied to solve household operations involving compliant manipulation. However, previous RL methods have primarily focused on designing a policy for a specific operation that limits their applicability and requires separate training for every new operation. We propose a constraint-aware policy that is applicable to various unseen manipulations by grouping several manipulations together based on the type of physical constraint involved. The type of physical constraint determines the characteristic of the imposed force direction; thus, a generalized policy is trained in the environment and reward designed on the basis of this characteristic. This paper focuses on two types of physical constraints: prismatic and revolute joints. Experiments demonstrated that the same policy could successfully execute various compliant-manipulation operations, both in the simulation and reality. We believe this study is the first step toward realizing a generalized household-robot

    Slc12a8 in the lateral hypothalamus maintains energy metabolism and skeletal muscle functions during aging

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    Sarcopenia and frailty are urgent socio-economic problems worldwide. Here we demonstrate a functional connection between the lateral hypothalamus (LH) and skeletal muscle through Slc12a8, a recently identified nicotinamide mononucleotide transporter, and its relationship to sarcopenia and frailty. Slc12a8-expressing cells are mainly localized in the LH. LH-specific knockdown of Slc12a8 in young mice decreases activity-dependent energy and carbohydrate expenditure and skeletal muscle functions, including muscle mass, muscle force, intramuscular glycolysis, and protein synthesis. LH-specific Slc12a8 knockdown also decreases sympathetic nerve signals at neuromuscular junctions and β2-adrenergic receptors in skeletal muscle, indicating the importance of the LH-sympathetic nerve-β2-adrenergic receptor axis. LH-specific overexpression of Slc12a8 in aged mice significantly ameliorates age-associated decreases in energy expenditure and skeletal muscle functions. Our results highlight an important role of Slc12a8 in the LH for regulation of whole-body metabolism and skeletal muscle functions and provide insights into the pathogenesis of sarcopenia and frailty during aging

    Network-dependent modulation of brain activity during sleep

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    AbstractBrain activity dynamically changes even during sleep. A line of neuroimaging studies has reported changes in functional connectivity and regional activity across different sleep stages such as slow-wave sleep (SWS) and rapid-eye-movement (REM) sleep. However, it remains unclear whether and how the large-scale network activity of human brains changes within a given sleep stage. Here, we investigated modulation of network activity within sleep stages by applying the pairwise maximum entropy model to brain activity obtained by functional magnetic resonance imaging from sleeping healthy subjects. We found that the brain activity of individual brain regions and functional interactions between pairs of regions significantly increased in the default-mode network during SWS and decreased during REM sleep. In contrast, the network activity of the fronto-parietal and sensory-motor networks showed the opposite pattern. Furthermore, in the three networks, the amount of the activity changes throughout REM sleep was negatively correlated with that throughout SWS. The present findings suggest that the brain activity is dynamically modulated even in a sleep stage and that the pattern of modulation depends on the type of the large-scale brain networks
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