Newly Synthesized Compound, PABA-Ursodeoxycholic Acid, for Evaluation of Intestinal Bacteria

From the standpoint of utilizing a distinctive feature of para-aminobenzoic acid (PABA) and intestinal bile acid metabolism, a conjugate of ursodeoxycholic acid with PABA (PABA-UDCA) was newly synthesized for studying whether it can be a good material or not to evaluate enteric bacteria. In incubation experiment, this compound was reasonably deconjugated by cholylglycine hydrolase resulting in the release of PABA. In animal experiment, urinary excretions of PABA were determined during six hours following oral administration of 10 mg PABA-UDCA. Control rats (n=7) excreted 140.1 ± 59.5 μ,g (mean ± SD) of PABA. By contrast, the rats (n=9) with intestinal antisepsis by antibiotic administration excreted less (18.3 ± 16. 7 μg; P < 0.001) whereas those with intestinal bacterial overgrowth by making enteric blind loop excreted more (451.1 ± 223.6 μg; P < 0.01). These observations indicate that this new compound is likely to offer a simple and rapid method for evaluation of the intestinal microorganisms

A novel partner for the GTP-bound forms of rho and rac

AbstractUsing the yeast two hybrid system and overlay assays we identified a putative rho/rac effector, citron, which interacts with the GTP-bound forms of rho and rac1, but not with cdc42. Extensive homologies to known proteins were not observed. This 183 kDa protein contains a C6H2 zinc finger, a PH domain, and a long coiled-coil forming region including 4 leucine zippers and the rho/rac binding site. We recently identified three others putative rho effectors characterized by a common rho binding motif. Citron does not share this motif and displays a distinctive protein organization, thus defining a separate class of rho partners

Three-dimensional fluorescence imaging using the transport of intensity equation

We propose a nonscanning three-dimensional (3-D) fluorescence imaging technique using the transport of intensity equation (TIE) and free-space Fresnel propagation. In this imaging technique, a phase distribution corresponding to defocused fluorescence images with a point-light-source-like shape is retrieved by a TIE-based phase retrieval algorithm. From the obtained phase distribution, and its corresponding amplitude distribution, of the defocused fluorescence image, various images at different distances can be reconstructed at the desired plane after Fresnel propagation of the complex wave function. Through the proposed imaging approach, the 3-D fluorescence imaging can be performed in multiple planes. The fluorescence intensity images are captured with the help of an electrically tunable lens; hence, the imaging technique is free from motion artifacts. We present experimental results corresponding to microbeads and a biological sample to demonstrate the proposed 3-D fluorescence imaging technique

Deficiency of mDia, an Actin Nucleator, Disrupts Integrity of Neuroepithelium and Causes Periventricular Dysplasia

During development of the central nervous system, the apical-basal polarity of neuroepithelial cells is critical for homeostasis of proliferation and differentiation of neural stem cells. While adherens junctions at the apical surface of neuroepithelial cells are important for maintaining the polarity, the molecular mechanism regulating integrity of these adherens junctions remains largely unknown. Given the importance of actin cytoskeleton in adherens junctions, we have analyzed the role of mDia, an actin nucleator and a Rho effector, in the integrity of the apical adherens junction. Here we show that mDia1 and mDia3 are expressed in the developing brain, and that mDia3 is concentrated in the apical surface of neuroepithelium. Mice deficient in both mDia1 and mDia3 develop periventricular dysplastic mass widespread throughout the developing brain, where neuroepithelial cell polarity is impaired with attenuated apical actin belts and loss of apical adherens junctions. In addition, electron microscopic analysis revealed abnormal shrinkage and apical membrane bulging of neuroepithelial cells in the remaining areas. Furthermore, perturbation of Rho, but not that of ROCK, causes loss of the apical actin belt and adherens junctions similarly to mDia-deficient mice. These results suggest that actin cytoskeleton regulated by Rho-mDia pathway is critical for the integrity of the adherens junctions and the polarity of neuroepithelial cells, and that loss of this signaling induces aberrant, ectopic proliferation and differentiation of neural stem cells

A role for mDia, a Rho-regulated actin nucleator, in tangential migration of interneuron precursors.

神経細胞の配置メカニズムを解明－抑制性神経前駆細胞に特有の移動の機構が明らかに. 京都大学プレスリリース. 2012-1-16.In brain development, distinct types of migration, radial migration and tangential migration, are shown by excitatory and inhibitory neurons, respectively. Whether these two types of migration operate by similar cellular mechanisms remains unclear. We examined neuronal migration in mice deficient in mDia1 (also known as Diap1) and mDia3 (also known as Diap2), which encode the Rho-regulated actin nucleators mammalian diaphanous homolog 1 (mDia1) and mDia3. mDia deficiency impaired tangential migration of cortical and olfactory inhibitory interneurons, whereas radial migration and consequent layer formation of cortical excitatory neurons were unaffected. mDia-deficient neuroblasts exhibited reduced separation of the centrosome from the nucleus and retarded nuclear translocation. Concomitantly, anterograde F-actin movement and F-actin condensation at the rear, which occur during centrosomal and nuclear movement of wild-type cells, respectively, were impaired in mDia-deficient neuroblasts. Blockade of Rho-associated protein kinase (ROCK), which regulates myosin II, also impaired nuclear translocation. These results suggest that Rho signaling via mDia and ROCK critically regulates nuclear translocation through F-actin dynamics in tangential migration, whereas this mechanism is dispensable in radial migration

Facilitation of Th1-mediated immune response by prostaglandin E receptor EP1

Prostaglandin E2 (PGE2) exerts its actions via four subtypes of the PGE receptor, EP1–4. We show that mice deficient in EP1 exhibited significantly attenuated Th1 response in contact hypersensitivity induced by dinitrofluorobenzene (DNFB). This phenotype was recapitulated in wild-type mice by administration of an EP1-selective antagonist during the sensitization phase, and by adoptive transfer of T cells from sensitized EP1−/− mice. Conversely, an EP1-selective agonist facilitated Th1 differentiation of naive T cells in vitro. Finally, CD11c+ cells containing the inducible form of PGE synthase increased in number in the draining lymph nodes after DNFB application. These results suggest that PGE2 produced by dendritic cells in the lymph nodes acts on EP1 in naive T cells to promote Th1 differentiation

ROCK and mDia1 antagonize in Rho-dependent Rac activation in Swiss 3T3 fibroblasts

The small GTPase Rho acts on two effectors, ROCK and mDia1, and induces stress fibers and focal adhesions. However, how ROCK and mDia1 individually regulate signals and dynamics of these structures remains unknown. We stimulated serum-starved Swiss 3T3 fibroblasts with LPA and compared the effects of C3 exoenzyme, a Rho inhibitor, with those of Y-27632, a ROCK inhibitor. Y-27632 treatment suppressed LPA-induced formation of stress fibers and focal adhesions as did C3 exoenzyme but induced membrane ruffles and focal complexes, which were absent in the C3 exoenzyme-treated cells. This phenotype was suppressed by expression of N17Rac. Consistently, the amount of GTP-Rac increased significantly by Y-27632 in LPA-stimulated cells. Biochemically, Y-27632 suppressed tyrosine phosphorylation of paxillin and focal adhesion kinase and not that of Cas. Inhibition of Cas phosphorylation with PP1 or expression of a dominant negative Cas mutant inhibited Y-27632–induced membrane ruffle formation. Moreover, Crk-II mutants lacking in binding to either phosphorylated Cas or DOCK180 suppressed the Y-27632–induced membrane ruffle formation. Finally, expression of a dominant negative mDia1 mutant also inhibited the membrane ruffle formation by Y-27632. Thus, these results have revealed the Rho-dependent Rac activation signaling that is mediated by mDia1 through Cas phosphorylation and antagonized by the action of ROCK

Mental Health Effects of Tourism in the South Pacific Islands

本研究は，8日間の南太平洋諸島への滞在中における，活動，交流，および調整された食事摂取などのライフスタイルの変化が，特に精神的健康度に及ぼす影響について検討することを目的とした. 自主的に参加した中高齢女性9人（66.9 ± 4.7歳）を対象に，質問紙を用いて，抑うつ傾向 (CES-D)，気分プロフィール (POMS)，個人空間の確保（プライベート空問機能尺度）について滞在初期および終期に調査を行い，滞在前と比較した. また，滞在時に毎日撮影した顔写真を用いた笑顔の表情分析 (FACS : Facial Action Coding System)，さらに滞在時に経験した感情についての語りを内容分析した. その結果，滞在による身体への影響については，体重および腹囲の減少を認めた. 精神的健康への影響については，抑うつ傾向有りの者は，初期に増加したが，終期には皆無となり，POMSの「否定的気分」は初期から終期にかけて低下し，「肯定的気分」は初期に低下した後，終期に上昇した. 個人空間の確保については，「共布空間」と「自己開放」が終期に上昇した. 表情分析および内容分析については，「笑顔」および「肯定的感情」は滞在4日日に最高値となりその後低下し，「否定的感情」は滞在初日に強くその後消失したが，これらの変化は，CES-D や POMS の変化と同期していた. 以上の結果から，中高齢女性の南太平洋諸島への滞在によって，身体的健康度の改善に加えて精神的健康度の改善が示された.The present study investigated the effects of tourism in the South Pacific Islands with a controlled life-style on the mental health status of elderly subjects. A questionnaire survey on mental health, expression analysis and content analysis of emotional experience were conducted on 9 healthy female subjects (mean age, 66.9 ± 4.7 years) during 8 days of tourism. Self-administered questionnaire surveys were conducted prior to, early and late in their stay regarding depressive tendencies (CES-D), mood profile (Profile of Mood States; POMS), and personal space acquisition (Personal Space Scale; PSS). Expression analysis of facial photographs with the Facial Action Coding System (F ACS), and content analysis of self-reported emotional experiences were also performed. Body weight and abdominal circumference were decreased in the stay. Depressive tendencies increased early in the stay but were absent late in the stay. The questionnaire surveys revealed that negative mood was high in the early part of the stay, but decreased late in the stay, while positive mood decreased early in the stay and increased late in the stay regarding the POMS sub-scales. Improved "common-space" and "self-liberation" were observed late in the stay on the PSS. Expression analysis and content analysis of emotional experience revealed that "smiles" and "positive emotions" increased from early in the stay, peaked on day 4, and afterwards gradually decreased. On the other hand, "negative emotions" were higher in the early stay, but afterwards decreased and later disappeared. These observed transitions during the course of the stay approximately synchronized with the questionnaire results, demonstrating an improvement in the mental health of elderly individuals during tourism in the South Pacific Islands