Modeling photometric variations due to a global inhomogeneity on an obliquely rotating star: application to lightcurves of white dwarfs

We develop a general framework to compute photometric variations induced by the oblique rotation of a star with an axisymmetric inhomogeneous surface. We apply the framework to compute lightcurves of white dwarfs adopting two simple models of their surface inhomogeneity. Depending on the surface model and the location of the observer, the resulting lightcurve exhibits a departure from a purely sinusoidal curve that are observed for a fraction of white dwarfs. As a specific example, we fit our model to the observed phase-folded lightcurve of a fast-spinning white dwarf ZTF J190132.9+145808.7 (with the rotation period of 419s). We find that the size and obliquity angle of the spot responsible for the photometric variation are \dts \approx 60^\circ and \thetaS \approx 60^\circ or $90^\circ$, respectively, implying an interesting constraint on the surface distribution of the magnetic field on white dwarfs.Comment: 25 pages, 9 figures, accepted for publication in PAS

Effects of glycosylation on swimming ability and flagellar polymorphic transformation in Pseudomonas syringae pv. tabaci 6605

The role of flagellin glycosylation on motility was investigated in Pseudomonas syringae pv. tabaci. The swimming activity of glycosylation-defective mutants was prominently decreased in a highly viscous medium. The mutants showed differences in polymorphic transitions and in the bundle formation of flagella, indicating that glycosylation stabilizes the filament structure and lubricates the rotation of the bundle.</p

Study of human Wharton’s duct structure and its relationship with salivary flow

Of all major salivary glands, the human submandibular gland secretes the largest amount of saliva. Along with the sublingual duct, the main duct (Wharton’s duct) is known to open into the sublingual caruncula; however, reports regarding this common opening structure are scarce and details unclear. The structure of Wharton’s duct opening is quite different from that of parotid duct (Stensen’s duct) opening in its overall size and diameter despite what is commonly noted in text books. About 85% of sialolith occurrences in humans is in the submandibular gland and duct, which causes local pain during swallowing in most cases. The details of Wharton’s duct’s inner structure is relatively unknown, and further investigation is necessary to understand its special characteristics and clinical applications. In this study, we observed the inner structure of the ducts’ common opening area by scanning electron microscopy and confirmed a large number of blood vessels present in the connective tissue layer just under the epithelium. In addition, we confirmed the presence of smooth muscle in the same area using smooth muscle actin antibody. These structural findings suggest that Wharton’s duct itself is likely responsible for the regulation of salivary flow

Calpain-dependent disruption of nucleo-cytoplasmic transport in ALS motor neurons

Nuclear dysfunction in motor neurons has been hypothesized to be a principal cause of amyotrophic lateral sclerosis (ALS) pathogenesis. Here, we investigated the mechanism by which the nuclear pore complex (NPC) is disrupted in dying motor neurons in a mechanistic ALS mouse model (adenosine deaminase acting on RNA 2 (ADAR2) conditional knockout (AR2) mice) and in ALS patients. We showed that nucleoporins (Nups) that constituted the NPC were cleaved by activated calpain via a Ca2+-permeable AMPA receptor-mediated mechanism in dying motor neurons lacking ADAR2 expression in AR2 mice. In these neurons, nucleo-cytoplasmic transport was disrupted, and the level of the transcript elongation enzyme RNA polymerase II phosphorylated at Ser2 was significantly decreased. Analogous changes were observed in motor neurons lacking ADAR2 immunoreactivity in sporadic ALS patients. Therefore, calpain-dependent NPC disruption may participate in ALS pathogenesis, and inhibiting Ca2+-mediated cell death signals may be a therapeutic strategy for ALS.UTokyo Research掲載「核と細胞質間の分子輸送経路の破綻が筋萎縮性側索硬化症に関与」 URI: http://www.u-tokyo.ac.jp/ja/utokyo-research/research-news/disruption-of-molecule-transport-pathway-between-nucleus-and-cytoplasm-involved-in-als.htmlUTokyo Research "Disruption of molecule transport pathway between nucleus and cytoplasm involved in ALS" URI: http://www.u-tokyo.ac.jp/en/utokyo-research/research-news/disruption-of-molecule-transport-pathway-between-nucleus-and-cytoplasm-involved-in-als.htm

Mechanical Properties and Histological Evaluation of Bone Grafting Materials Containing Different Ratios of Calcium Phosphate Cement and Porous β-tricalcium Phosphate Granules

Article信州医学雑誌 66(2): 139-150(2018)journal articl

Short-Term Effects of Acupuncture on Open-Angle Glaucoma in Retrobulbar Circulation: Additional Therapy to Standard Medication

Background. The relation between glaucoma and retrobulbar circulation in the prognosis has been indicated. Purpose. To investigate the effects of acupuncture on retrobulbar circulation in open-angle glaucoma (OAG) patients. Methods. Eleven OAG patients (20 eyes with OAG) who were treated by topical antiglaucoma medications for at least 3 months were enrolled. Acupuncture was performed once at acupoints BL2, M-HN9, ST2, ST36, SP6, KI3, LR3, GB20, BL18, and BL23 bilaterally. Retrobulbar circulation was measured with color Doppler imaging, and intraocular pressure (IOP) was also measured at rest and one hour after rest or before and after acupuncture. Results. The Δ value of the resistive index in the short posterior ciliary artery (P < .01) and the Δ value of IOP (P < .01) were decreased significantly by acupuncture compared with no acupuncture treatment. Conclusions. Acupuncture can improve the retrobulbar circulation and IOP, which may indicate the efficacy of acupuncture for OAG

Characterizing the flagellar filament and the role of motility in bacterial prey-penetration by Bdellovibrio bacteriovorus

The predatory bacterium Bdellovibrio bacteriovorus swims rapidly by rotation of a single, polar flagellum comprised of a helical filament of flagellin monomers, contained within a membrane sheath and powered by a basal motor complex. Bdellovibrio collides with, enters and replicates within bacterial prey, a process previously suggested to firstly require flagellar motility and then flagellar shedding upon prey entry. Here we show that flagella are not always shed upon prey entry and we study the six fliC flagellin genes of B. bacteriovorus, finding them all conserved and expressed in genome strain HD100 and the widely studied lab strain 109J. Individual inactivation of five of the fliC genes gave mutant Bdellovibrio that still made flagella, and which were motile and predatory. Inactivation of the sixth fliC gene abolished normal flagellar synthesis and motility, but a disordered flagellar sheath was still seen. We find that this non-motile mutant was still able to predate when directly applied to lawns of YFP-labelled prey bacteria, showing that flagellar motility is not essential for prey entry but important for efficient encounters with prey in liquid environments

High‐resolution archaellum structure reveals a conserved metal‐binding site

Many archaea swim by means of archaella. While the archaellum is similar in function to its bacterial counterpart, its structure, composition, and evolution are fundamentally different. Archaella are related to archaeal and bacterial type IV pili. Despite recent advances, our understanding of molecular processes governing archaellum assembly and stability is still incomplete. Here, we determine the structures of Methanococcus archaella by X-ray crystallography and cryo-EM. The crystal structure of Methanocaldococcus jannaschii FlaB1 is the first and only crystal structure of any archaellin to date at a resolution of 1.5 angstrom, which is put into biological context by a cryo-EM reconstruction from Methanococcus maripaludis archaella at 4 angstrom resolution created with helical single-particle analysis. Our results indicate that the archaellum is predominantly composed of FlaB1. We identify N-linked glycosylation by cryo-EM and mass spectrometry. The crystal structure reveals a highly conserved metal-binding site, which is validated by mass spectrometry and electron energy-loss spectroscopy. We show invitro that the metal-binding site, which appears to be a widespread property of archaellin, is required for filament integrity

Onjisaponins, from the root of Polygala tenuifolia Willdenow, as effective adjuvants for nasal influenza and diphtheria -pertussis-tetanus vaccines

Abstract Active substances from hot water extracts from 267 different Chinese and Japanese medicinal herbs were screened for mucosal adjuvant activity with influenza HA vaccine in mice. The extract from the root of Polygala tenuifolia was found to contain potent mucosal adjuvant activity. The active substances were purified and identified as onjisaponins A, E, F, and G. When each onjisaponin (10 mg) was intranasally (i.n.) inoculated with influenza vaccine (10 mg) in mice, serum hemagglutination-inhibiting (HI) antibody titers increased 3-14 times over control mice administered vaccine alone after 4 weeks. When each onjisaponin (10 mg) was i.n. inoculated with the vaccine (10 mg) followed by i.n. vaccination of the vaccine alone after 3 weeks, serum HI antibody titers increased 27-50 fold over those mice given i.n. vaccinations without onjisaponins. These same conditions also significantly increased nasal anti-influenza virus IgA antibody titers. Two inoculations with onjisaponin F (1 mg) and influenza HA vaccine (1 mg) at 3 weeks intervals, significantly increased serum HI antibody and nasal anti-influenza virus IgA and IgG antibody titers after only 1 week over mice given HA vaccine alone after the secondary vaccination. Intranasal vaccination with onjisaponin F inhibited proliferation of mouse adapted influenza virus A/PR/8/34 in bronchoalveolar lavages of infected mice. Separate intranasal vaccinations with onjisaponins A, E, F, and G (10 mg) each and diphtheria-pertussis-tetanus (DPT) vaccine (10 mg) of mice followed by i.n. vaccination with DPT vaccine alone after 4 weeks showed significant increases in serum IgG and nasal IgA antibody titers after 2 weeks following secondary vaccination over mice vaccinated with DPT vaccine alone. All onjisaponins showed little hemolytic activity at concentrations up to 100 mg/ml. The results of this study suggest that onjisaponins may provide safe and potent adjuvants for intranasal inoculation of influenza HA and DPT vaccines