Reconstitution of prenyltransferase activity on nanodiscs by components of the rubber synthesis machinery of the Para rubber tree and guayule.

Natural rubber of the Para rubber tree (Hevea brasiliensis) is synthesized as a result of prenyltransferase activity. The proteins HRT1, HRT2, and HRBP have been identified as candidate components of the rubber biosynthetic machinery. To clarify the contribution of these proteins to prenyltransferase activity, we established a cell-free translation system for nanodisc-based protein reconstitution and measured the enzyme activity of the protein-nanodisc complexes. Co-expression of HRT1 and HRBP in the presence of nanodiscs yielded marked polyisoprene synthesis activity. By contrast, neither HRT1, HRT2, or HRBP alone nor a complex of HRT2 and HRBP manifested such activity. Similar analysis of guayule (Parthenium argentatum) proteins revealed that three HRT1 homologs (PaCPT1-3) manifested prenyltransferase activity only when co-expressed with PaCBP, the homolog of HRBP. Our results thus indicate that two heterologous subunits form the core prenyltransferase of the rubber biosynthetic machinery. A recently developed structure modeling program predicted the structure of such heterodimer complexes including HRT1/HRBP and PaCPT2/PaCBP. HRT and PaCPT proteins were also found to possess affinity for a lipid membrane in the absence of HRBP or PaCBP, and structure modeling implicated an amphipathic α-helical domain of HRT1 and PaCPT2 in membrane binding of these proteins.

Association of Serum Soluble CD163 with Polymyositis and Dermatomyositis, Especially in Anti-MDA5 Antibody-positive Cases.

OBJECTIVE: We elucidated the association of serum soluble CD163 (sCD163) with rapidly progressive interstitial lung disease (RP-ILD), autoantibody profiles, and serum ferritin in patients with polymyositis (PM), classic dermatomyositis (DM), and clinical amyopathic dermatomyositis (CADM). METHODS: Serum sCD163 levels were retrospectively measured by ELISA in patients with PM, classic DM, and CADM, as well as in healthy controls (HC). Repeat sera samples were obtained posttreatment from available patients. The associations between serum sCD163 levels and clinical information were analyzed. RESULTS: Serum sCD163 levels in patients with PM/classic DM/CADM were significantly higher than those in HC (n = 72, 56, 34, and 68, respectively; p < 0.001 for all comparisons). No significant difference was observed between serum sCD163 levels in patients with and without ILD (p = 0.16) or between those with RP-ILD and chronic ILD (p = 0.21). Serum sCD163 levels were significantly higher in patients with anti-MDA5 antibodies (n = 27) than in those without (p = 0.001). Serum sCD163 levels were weakly correlated with serum ferritin levels in the patients with PM, classic DM, and CADM (r = 0.21). Serum sCD163 levels decreased significantly following treatment in all patient groups (p = 0.003). CONCLUSION: The present results suggest an association of serum sCD163 with PM, classic DM, and CADM, especially in anti-MDA5 antibody-positive cases. However, serum sCD163 levels were not specifically associated with ILD or RP-ILD.

Metal-catalyzed hydrosilylation of alkenes and alkynes using dimethyl(pyridyl)silane.

Metal-catalyzed hydrosilylation of alkenes and alkynes using dimethyl(pyridyl)silane is described. The hydrosilylation of alkenes using dimethyl(2-pyridyl)silane (2-PyMe(2)SiH) proceeded well in the presence of a catalytic amount of RhCl(PPh(3))(3) with virtually complete regioselectivity. By taking advantage of the phase tag property of the 2-PyMe(2)Si group, hydrosilylation products were isolated in greater than 95% purity by simple acid-base extraction. Strategic catalyst recovery was also demonstrated. The hydrosilylation of alkynes using 2-PyMe(2)SiH proceeded with a Pt(CH(2)=CHSiMe(2))(2)O/P(t-Bu)(3) catalyst to give alkenyldimethyl(2-pyridyl)silanes in good yield with high regioselectivity. A reactivity comparison of 2-PyMe(2)SiH with other related hydrosilanes (3-PyMe(2)SiH, 4-PyMe(2)SiH, and PhMe(2)SiH) was also performed. In the rhodium-catalyzed reaction, the reactivity order of hydrosilane was 2-PyMe(2)SiH >> 3-PyMe(2)SiH, 4-PyMe(2)SiH, PhMe(2)SiH, indicating a huge rate acceleration with 2-PyMe(2)SiH. In the platinum-catalyzed reaction, the reactivity order of hydrosilane was PhMe(2)SiH, 3-PyMe(2)SiH >> 4-PyMe(2)SiH > 2-PyMe(2)SiH, indicating a rate deceleration with 2-PyMe(2)SiH and 4-PyMe(2)SiH. It seems that these reactivity differences stem primarily from the governance of two different mechanisms (Chalk-Harrod and modified Chalk-Harrod mechanisms). From the observed reactivity order, coordination and electronic effects of dimethyl(pyridyl)silanes have been implicated.

Outcomes of a 3-month weight loss exercise training in obese middle-aged women: with special reference to the relationship between weight loss and mood status / 体力科学

Exercise-induced changes in body composition are dependent on various external factors. The psychological factor seems to be an important determinant for reducing body mass. However, the effect of changes in mood on weight loss have not been thoroughly investigated. The purpose of this study was to investigate the relationships among mood status, body composition and anthropometric characteristics observed during an exercise training program. Thirty-four obese women, aged 46.5±7.7 years, participated in our 3-month weight loss program. Body mass and % fat significantly decreased from 66.3±7.1 kg to 59.8±6.5kg, and from 31.8±3.1% to 27.9±4.0% (<I>P</I><0.05), respectively. Aerobic power, as represented by maximal oxygen uptake, significantly increased (from 29.1±5.0 mlin/kg to 34.6±5.2 mlin/kg), and oxygen uptake corresponding to lactate threshold increased as well (from 17.2±2.8mlin/kg to 20.0±3.0mlin/kg) after training (<I>P</I><0.05) . Accord. ing to the degree of body mass change, the subjects were divided into the following two groups : good-responder group (Group G : -9.2±2.7 kg) and poor-responder group (Group P : -3.8±1.4 kg) . Analyses of variance revealed significant differences (<I>P</I><0.05) in total mood disturbance between Group G (103.54±16.30) and Group P (115.20±21.17) . These results show the possibility of the effects of mood on the success of weight loss in obese middle-aged women.