Time-series photometry of Earth flyby asteroid 2012 DA14

Context. The object 2012 DA14 is a near-Earth asteroid with a size of several tens of meters. It had approached closely the Earth on 15 February, 2013 UT, providing an opportunity for precise measurements of this tiny asteroid. Aims. The solar phase angle of 2012 DA14 had varied widely around its closest approach but was almost constant during the following night. We performed time-series photometric observations on those two nights to determine the rotational properties and phase effect. Methods. The observations were carried out using the 0.55-m telescope at Saitama University, Japan. The R-band images were obtained continuously over a 2 hr period at the closest approach and for about 5 hr on the next night. Results. The lightcurve data from the second night indicates a rotational period of 11.0 +1.8/-0.6 hr and a peak-to-peak amplitude of 1.59 +/- 0.02 mag. The brightness variation before and after the closest approach was separated into two components that are derived from the rotation and phase effect. We found that the phase curve slope of this asteroid is significantly shallower than those of other L-type asteroids. Conclusions. We suggest that 2012 DA14 is coated with a coarse surface that lacks fine regolith particles and/or a high albedo surface.Comment: 4 pages, 4 figures, accepted for publication in Astronomy and Astrophysic

Survey of Newly-found Nitrile Hydratase-Producing Microorganisma Grown at Higher Temperatures

We surveyed some novel nitrile hydratase-producing microorganisms through the enrichment culture technique at higher temperatures. We isolated several spore-forming filamentous bacteria from soil samples. One of them, strain 45A40 exhibited the highest nitrile hydratase activity. Based on taxonomical studies, strain 45A40 was identifind to be genus Streptomyces. It was the first example of a Streptomyces strain exhibiting high nitrile hydratase acitivity. We optimized the culture conditions of Streptomyces 45A40 to enhance the nitrile hydratase activity. The formation of nitrile hydratase was constitutive and was highly enhanced by the addition of cobalt ions. The enzyme acted on various nitriles and showed low Km value for 3-cyanopuridine. The enzyme exhibited tolerance against a high concentration of 3-cyanopyridine ; however, its heat stability was not outstanding.二トリルヒドラターゼは、温和な条件下で二トリルを水和し、極めて効率的にアミドを生産蓄積する反応を触媒することから、ポリマーの原料であるアクリルアミドの工場生産に応用されてきた(Fig.1(1)).またごく最近、ビタミン剤として家畜の飼料添加に用いられるニコチンアミドの工業生産にも本酵素の水和反応プロセスが応用されるようになった(Fig.1(2))1-3).本酵素は今日のバイオインダストリーにおいて、最もポテンシャルの高い酵素の一つであると言える。現在、アクリルアミド、ニコチンアミドの工場生産は、長澤ら4-6)によって確立された方法、即ちRhodococcus rhodochrous J1をコバルトイオンと尿素を添加した培地で培養し、著量の二トリルヒドラターゼを誘導生成させた菌体を直接触媒的に用いる生産プロセスが実用化されている。これまで二トリル分解菌の分離は、二トリルが一般的に低沸点で揮発性であることから、30℃以下の温度域で集積培養し、分離することが一派的であった。これまで報告されている高活性を示す二トリルヒドラターゼ生成菌としては、Pseudomonas属7), Rhodococcus属6,8)の細菌が知られている。新規二トリルヒドラターゼ生成菌の探索を目的として、今回、我々は比較的高沸点の二トリル化合物を単一炭素、窒素源として用いてこれまで試みられなかった37℃-50℃の中高温度域で集積培養を行う新たな二トリル分解菌の探索を試みた

骨－歯根膜線維の複合組織形成による三次元的な歯周組織再生技術の開発

Periodontal tissue is a distinctive tissue structure composed three-dimensionally of cementum, periodontal ligament (PDL) and alveolar bone. Severe periodontal diseases cause fundamental problems for oral function and general health, and conventional dental treatments are insufficient for healing to healthy periodontal tissue. Cell sheet technology has been used in many tissue regenerations, including periodontal tissue, to transplant appropriate stem/progenitor cells for tissue regeneration of a target site as a uniform tissue. However, it is still difficult to construct a three-dimensional structure of complex tissue composed of multiple types of cells, and the transplantation of a single cell sheet cannot sufficiently regenerate a large-scale tissue injury. Here, we fabricated a three-dimensional complex cell sheet composed of a bone-ligament structure by layering PDL cells and osteoblast-like cells on a temperature responsive culture dish. Following ectopic and orthotopic transplantation, only the complex cell sheet group was demonstrated to anatomically regenerate the bone-ligament structure along with the functional connection of PDL-like fibers to the tooth root and alveolar bone. This study represents successful three-dimensional tissue regeneration of a large-scale tissue injury using a bioengineered tissue designed to simulate the anatomical structure

Photopharmacological Manipulation of Mammalian CRY1 for Regulation of the Circadian Clock

CRY1 and CRY2 proteins are highly conserved components of the circadian clock that controls daily physiological rhythms. Disruption of CRY functions are related to many diseases, including circadian sleep phase disorder. Development of isoform-selective and spatiotemporally controllable tools will facilitate the understanding of shared and distinct functions of CRY1 and CRY2. Here, we developed CRY1-selective compounds that enable light-dependent manipulation of the circadian clock. From phenotypic chemical screening in human cells, we identified benzophenone derivatives that lengthened the circadian period. These compounds selectively interacted with the CRY1 photolyase homology region, resulting in activation of CRY1 but not CRY2. The benzophenone moiety rearranged a CRY1 region called the "lid loop"located outside of the compound-binding pocket and formed a unique interaction with Phe409 in the lid loop. Manipulation of this key interaction was achieved by rationally designed replacement of the benzophenone with a switchable azobenzene moiety whose cis-trans isomerization can be controlled by light. The metastable cis form exhibited sufficiently high half-life in aqueous solutions and structurally mimicked the benzophenone unit, enabling reversible period regulation over days by cellular irradiation with visible light. This study revealed an unprecedented role of the lid loop in CRY-compound interaction and paves the way for spatiotemporal regulation of CRY1 activity by photopharmacology for molecular understanding of CRY1-dependent functions in health and disease

Dentin-pulp regeneration by 3D layered cell sheet

The dentin-pulp complex is a unique structure in teeth that contains both hard and soft tissues. Generally, deep caries and trauma cause damage to the dentin-pulp complex, and if left untreated, this damage will progress to irreversible pulpitis. The aim of this study was to fabricate a layered cell sheet composed of rat dental pulp (DP) cells and odontogenic differentiation of pulp (OD) cells and to investigate the ability to regenerate the dentin-pulp complex in a scaffold tooth. We fabricated two single cell sheets composed of DP cells (DP cell sheet) or OD cells (OD cell sheet) and a layered cell sheet made by layering both cells. The characteristics of the fabricated cell sheets were analyzed using light microscopy, scanning electron microscopy (SEM), hematoxylin-eosin (HE) staining, and immunohistochemistry (IHC). Furthermore, the cell sheets were transplanted into the subrenal capsule of immunocompromised mice for 8 weeks. Following this, the regenerative capacity to form dentin-like tissue was evaluated using micro-computed tomography (Micro-CT), HE staining, and IHC. The findings of SEM and IHC confirmed that layered cell sheets fabricated by stacking OD cells and DP cells maintained their cytological characteristics. Micro-CT of layered cell sheet transplants revealed a mineralized capping of the access cavity in the crown area, similar to that of natural dentin. In contrast, the OD cell sheet group demonstrated the formation of irregular fragments of mineralized tissue in the pulp cavity, and the DP cell sheet did not develop any hard tissue. Moreover, bone volume/tissue volume (BV/TV) showed a significant increase in hard tissue formation in the layered cell sheet group compared to that in the single cell sheet group (p<0.05). HE staining also showed a combination of soft and hard tissue formation in the layered cell sheet group. Furthermore, IHC confirmed that the dentin-like tissue generated from the layered cell sheet expressed characteristic markers of dentin but not bone equivalent to that of a natural tooth. In conclusion, this study demonstrates the feasibility of regenerating dentin-pulp complex using a bioengineered tissue designed to simulate the anatomical structure

片側末梢投与されたA型ボツリヌス毒素は動物モデルにおいて両側三叉神経節に局在する

Peripheral nerve injury leads to sensory ganglion hyperexcitation, which increases neurotransmitter release and neuropathic pain. Botulinum toxin type A (BoNT/A) regulates pain transmission by reducing neurotransmitter release, thereby attenuating neuropathic pain. Despite multiple studies on the use of BoNT/A for managing neuropathic pain in the orofacial region, its exact mechanism of transport remains unclear. In this study, we investigated the effects of BoNT/A in managing neuropathic pain in two different animal models and its transport mechanism in the trigeminal nerve. Intraperitoneal administration of cisplatin induced bilateral neuropathic pain in the orofacial region, reducing the head withdrawal threshold to mechanical stimulation. Unilateral infraorbital nerve constriction (IONC) also reduced the ipsilateral head withdrawal threshold to mechanical stimulation. Unilateral peripheral administration of BoNT/A to the rat whisker pad attenuated cisplatin-induced pain behavior bilaterally. Furthermore, contralateral peripheral administration of BoNT/A attenuated neuropathy-induced behavior caused by IONC. We also noted the presence of BoNT/A in the blood using the mouse bioassay. In addition, the Alexa Fluor-488-labeled C-terminal half of the heavy chain of BoNT/A (BoNT/A-Hc) was localized in the neurons of the bilateral trigeminal ganglia following its unilateral administration. These findings suggest that axonal and hematogenous transport are involved in the therapeutic effects of peripherally administered BoNT/A in the orofacial region