Membrane Anchor R9AP Potentiates GTPase-accelerating Protein Activity of RGS11·Gβ\u3csub\u3e5\u3c/sub\u3e Complex and Accelerates Inactivation of the mGluR6-G\u3csub\u3e0\u3c/sub\u3e Signaling

The R7 subfamily of RGS proteins critically regulates neuronal G protein-signaling pathways that are essential for vision, nociception, motor coordination, and reward processing. A member of the R7 RGS family, RGS11, is a GTPase-accelerating protein specifically expressed in retinal ON-bipolar cells where it forms complexes with the atypical G protein β subunit, Gβ5, and transmembrane protein R9AP. Association with R9AP has been shown to be critical for the proteolytic stability of the complex in the retina. In this study we report that R9AP can in addition stimulate the GTPase-accelerating protein activity of the RGS11·Gβ5 complex at Gαo. Single turnover GTPase assays reveal that R9AP co-localizes RGS11·Gβ5 and Gαo on the membrane and allosterically potentiates the GTPase-accelerating function of RGS11·Gβ5. Reconstitution of mGluR6-Gαo signaling in Xenopus oocytes indicates that RGS11·Gβ5-mediated GTPase acceleration in this system requires co-expression of R9AP. The results provide new insight into the regulation of mGluR6-Gαo signaling by the RGS11·Gβ5·R9AP complex and establish R9AP as a general GTPase-accelerating protein activity regulator of R7 RGS complexes

Comparative Evaluation of Direct Thrombin and Factor Xa Inhibitors with Antiplatelet Agents under Flow and Static Conditions: An In Vitro Flow Chamber Model

Dabigatran and rivaroxaban are novel oral anticoagulants that specifically inhibit thrombin and factor Xa, respectively. The aim of this study is to elucidate antithrombotic properties of these anticoagulant agents under arterial and venous shear conditions. Whole blood samples treated with dabigatran or rivaroxaban at 250, 500, and 1000 nM, with/without aspirin and AR-C66096, a P2Y12 antagonist, were perfused over a microchip coated with collagen and tissue thromboplastin at shear rates of 240 and 600 s−1. Fibrin-rich platelet thrombus formation was quantified by monitoring flow pressure changes. Dabigatran at higher concentrations (500 and 1000 nM) potently inhibited thrombus formation at both shear rates, whereas 1000 nM of rivaroxaban delayed, but did not completely inhibit, thrombus formation. Dual antiplatelet agents weakly suppressed thrombus formation at both shear rates, but intensified the anticoagulant effects of dabigatran and rivaroxaban. The anticoagulant effects of dabigatran and rivaroxaban were also evaluated under static conditions using thrombin generation (TG) assay. In platelet-poor plasma, dabigatran at 250 and 500 nM efficiently prolonged the lag time (LT) and moderately reduce peak height (PH) of TG, whereas rivaroxaban at 250 nM efficiently prolonged LT and reduced PH of TG. In platelet-rich plasma, however, both anticoagulants efficiently delayed LT and reduced PH of TG. Our results suggest that dabigatran and rivaroxaban may exert distinct antithrombotic effects under flow conditions, particularly in combination with dual antiplatelet therapy

Exploiting the potential of meroterpenoid cyclases to expand the chemical space of fungal meroterpenoids

Fungal meroterpenoids are a diverse group of hybrid natural products with impressive structural complexity and high potential as drug candidates. In this work, we evaluate the promiscuity of the early structure diversity-generating step in fungal meroterpenoid biosynthetic pathways: the multibond-forming polyene cyclizations catalyzed by the yet poorly understood family of fungal meroterpenoid cyclases. In total, 12 unnatural meroterpenoids were accessed chemoenzymatically using synthetic substrates. Their complex structures were determined by 2D NMR studies as well as crystalline-sponge-based X-ray diffraction analyses. The results obtained revealed a high degree of enzyme promiscuity and experimental results, together with quantum chemical calculations provided a deeper insight into the catalytic activity of this new family of non-canonical terpene cyclases. The knowledge obtained paves the way to design and engineer artificial pathways towards second generation meroterpenoids with valuable bioactivities based on combinatorial biosynthetic strategies.Accepted manuscrip

ミャンマー産植物Premna serratifoliaとJatropha multifida及び海綿Clathria proliferaに含まれるメラニン産生制御成分に関する研究

富山大学・富医薬博甲第305号・禹 昭年・2019/03/26当該博士論文は以下の項評論文で構成されています。①Woo, SY., Win, N.N., Wong, C.P. et al. Two new pyrrolo-2-aminoimidazoles from a Myanmarese marine sponge, Clathria prolifera, J Nat Med (2018) 72: 803-807. https://doi.org/10.1007/s11418-018-1205-y This is a pre-print of an article published in Journal of Natural Medicines. The final authenticated version is available online at: https://doi.org/10.1007/s11418-018-1205-y”.②So-Yeun Woo et al. Lignans with melanogenesis effects from Premna serratifolia wood, Fitoterapia (2019) 133:35-42. https://doi.org/10.1016/j.fitote.2018.12.008③So-Yeun Woo et al. A New Tetrahydrofuran Lignan from Premna serratifolia Wood, Natural Product Communications (2019) 14:113-116. https://doi.org/10.1177/1934578X1901400130富山大

Region of Interest Coding in Volumetric Images with Shape-Adaptive Wavelet Transform

We evaluated some arbitrary-shape ROI (Region of Interest) coding techniques for three-dimensional volumetric images, and through the observation we propose a flexible ROI coding with efficient compression performance. In arbitrary-shape ROI coding, the object in an image is coded with higher fidelity than the rest of the image, together with the shape information, which indicates the region of the object. In our proposed method (named as SA-ROI), in which shape-adaptive wavelet transform and scaling-based ROI coding are incorporated, the samples within the object are transformed with three-dimensional shape-adaptive wavelet transform according to its shape-information. If necessary, the background is also transformed by shape-adaptive wavelet transform independently. Then the samples within the object are scaled up by a certain number of bit-shifts, and encoded from the MSB (Most Significant Bit) plane by plane so that coefficients within the object are encoded earlier and have higher fidelity than the background. Compared with the scaling-based ROI coding using ordinary wavelet transform, which has almost the same ROI coding functionalities, SAROI outperforms by 5% in lossless compression ratio. Also in lossy coding, except at very low coding rates, SA-ROI has better compression performance

Only One of the Five CheY Homologs in Vibrio cholerae Directly Switches Flagellar Rotation

Vibrio cholerae has three sets of chemotaxis (Che) proteins, including three histidine kinases (CheA) and four response regulators (CheY) that are encoded by three che gene clusters. We deleted the cheY genes individually or in combination and found that only the cheY3 deletion impaired chemotaxis, reinforcing the previous conclusion that che cluster II is involved in chemotaxis. However, this does not exclude the involvement of the other clusters in chemotaxis. In other bacteria, phospho-CheY binds directly to the flagellar motor to modulate its rotation, and CheY overexpression, even without CheA, causes extremely biased swimming behavior. We reasoned that a V. cholerae CheY homolog, if it directly controls flagellar rotation, should also induce extreme swimming behavior when overproduced. This was the case for CheY3 (che cluster II). However, no other CheY homolog, including the putative CheY (CheY0) protein encoded outside the che clusters, affected swimming, demonstrating that these CheY homologs cannot act directly on the flagellar motor. CheY4 very slightly enhanced the spreading of an Escherichia coli cheZ mutant in semisolid agar, raising the possibility that it can affect chemotaxis by removing a phosphoryl group from CheY3. We also found that V. cholerae CheY3 and E. coli CheY are only partially exchangeable. Mutagenic analyses suggested that this may come from coevolution of the interacting pair of proteins, CheY and the motor protein FliM. Taken together, it is likely that the principal roles of che clusters I and III as well as cheY0 are to control functions other than chemotaxis

Potential diagnostic markers for disseminated intravascular coagulation of sepsis

Disseminated intravascular coagulation (DIC) is an acquired thrombo-haemorrhagic disorder which arises in clinical scenarios like sepsis, trauma and malignancies. The clinic-laboratory diagnosis of DIC is made in a patient who develops the combination of laboratory abnormalities in the appropriate clinical scenario. The most common laboratory parameters in this setting have been the clotting profile, platelet count, serum fibrinogen and fibrin degradation markers. These tests had the advantage that they could be performed easily and in most laboratories. However, with the better understanding of the pathophysiology of DIC, in recent years, more specific tests have been suggested to be useful in this setting. The newer tests can also prove to be useful in prognostication in DIC. In addition, they may provide assistance in the selection and monitoring of patients diagnosed with DI

Axilloaxillary bypass for the treatment of subclavian artery stenosis complicated by bilateral common carotid artery occlusion: Technical case report

OBJECTIVE AND IMPORTANCE: We successfully treated a patient with stenosis of the left subclavian artery, complicated by bilateral common carotid artery occlusion, via axilloaxillary bypass surgery. CLINICAL PRESENTATION: A 67-year-old patient with a history of hypertension and cerebral infarction underwent neck irradiation for treatment of a vocal cord tumor. Three months later, he began to experience transient tetraparesis several times per day. The blood pressure measurements for his right and left arms were different. Supratentorial blood flow was markedly low. The common carotid arteries were bilaterally occluded, and the right vertebral artery was hypoplastic. Therefore, only the left vertebral artery contributed to the patient\u27s cerebral circulation; his left subclavian artery was severely stenotic. INTERVENTION: The patient underwent axilloaxillary bypass surgery because the procedure avoids thoracotomy or sternotomy, manipulation of the carotid artery, and interruption of the vertebral artery blood flow. The patient has been free of symptoms for more than 5 years. CONCLUSION: Neurosurgeons should be aware that extra-anatomic bypass surgery is an effective treatment option for selected patients with cerebral ischemia