Solvent polarity effects on supramolecular chirality of a polyfluorene‐thiophene copolymer

This study demonstrates the supramolecular chirality control of a conjugated polymer via solvent polarity. We designed and synthesized a chiral polyfluorene‐thiophene copolymer having two different chiral side chains at the 9‐position of the fluorene unit. Chiral cyclic and alkyl ethers with different polarities were selected as the chiral side chains. The sign of the circular dichroism spectra in the visible wavelength region was affected by the solvent system, resulting from the change of supramolecular structure. The estimation of the solubility parameter revealed that the solubility difference of the side chains contributed to the change of the circular dichroism sign, which was also observed in spin‐coated films prepared from good solvents having different polarities.     

Expression, purification, and crystallization of endopolygalacturonase from a pathogenic fungus, Stereum purpureum, in Escherichia coli

Endopolygalacturonases (EC 3.2.1.15) catalyze random hydrolysis of the alpha-1,4 glycosidic linkages in polygalacturonic acid, a component of pectin. Previously, we reported crystal structures of endogenously produced Stereum purprureum endopolygalacturonase I (endoPG I), both in its native form and complexed with its product, galacturonate. However, the substrate-binding mechanism of endoPG I is still unclear, because crystals have not yet been obtained with a substrate analog, or with mutant enzymes that can bind substrates. We describe here an expression system using Escherichia coli and a purification method to prepare functionally active endoPG I for such mutation and crystallographic studies. Expression in E. coli strain Origami (DE3) provided a soluble and active enzyme with proper disulfide bond formation, whereas the enzyme expressed in BL21 (DE3) was localized in inclusion bodies. A sufficient amount of recombinant endoPG I produced by Origami (DE3) was purified by a single-step procedure using cation exchange chromatography. The specific activity of recombinant endoPG I was equivalent to that of the enzyme produced by S. purpureum. Recombinant endoPG I was crystallized under the same conditions as those used for the native enzyme produced by S. purpureum. The crystals diffracted beyond 1.0 A resolution with synchrotron radiation.     

Vonoprazan-based triple therapy is non-inferior to susceptibility-guided proton pump inhibitor-based triple therapy for <Emphasis Type="Italic">Helicobacter pylori</Emphasis> eradication

Background

All Helicobacter pylori-infected patients are recommended for eradication with an appropriate regimen in each geographic area. The choice of the therapy is somewhat dependent on the antimicrobial susceptibility. The rate of clarithromycin resistance has been increasing and is associated with failure; thus, susceptibility testing is recommended before triple therapy with clarithromycin. However, antimicrobial susceptibility testing is not yet clinically available and an alternative newly developed acid inhibitor vonoprazan is used for triple therapy in Japan. The aim of this study was to determine whether vonoprazan-based triple therapy is plausible treatment in H. pylori eradication.

Methods

A retrospective observational study of H. pylori eradication was conducted in a single institute. The patients who requested antimicrobial susceptibility testing were treated with susceptibility-guided proton pump inhibitor-based triple therapy in International University of Health and Welfare Hospital from 2013 to 2016. Other patients were treated with empirical treatment with a proton pump inhibitor. From 2015 to 2016, vonoprazan-based triple treatment (vonoprazan, 20 mg; amoxicillin, 750 mg; and clarithromycin, 200 or 400 mg, b.i.d.) was conducted, and its effectiveness was compared with susceptibility-guided proton pump inhibitor-based triple therapy. We also investigated the improvement in eradication rate when antimicrobial susceptibility testing was performed, and compared the outcomes of vonoprazan-based and proton pump inhibitor-based empirical therapy.

Results

A total of 1355 patients who received first-line eradication treatment were enrolled in the present study. The eradication rates of the empirical proton pump inhibitor-based therapy and the vonoprazan-based therapy group in a per-protocol analysis were 86.3% (95% CI 83.8–88.8) and 97.4% (95% CI 95.7–99.1), respectively. In 212 patients who received antimicrobial susceptibility testing, the rate of clarithromycin resistant was 23.5% and the eradication rate in susceptibility-guided treatment was 95.7% (95% CI 92.9–98.4). The difference between susceptibility-guided and vonoprazan-based therapy was ??1.7% (95% CI ??4.9 to 1.5%), and the non-inferiority of vonoprazan-based triple therapy was confirmed.

Conclusions

Vonoprazan-based triple therapy was effective as susceptibility-guided triple therapy for H. pylori eradication. An empirical triple therapy with vonoprazan is preferable even in area with high rates of clarithromycin-resistance.Trial registration The study was retrospectively registered in University Hospital Medical Information Network (UMIN000032351)

     

Annexin A4 Is Involved in Proliferation,Chemo-Resistance and Migration and Invasion in Ovarian Clear Cell Adenocarcinoma Cells

Ovarian clear cell adenocarcinoma (CCC) is the second most common subtype of ovarian cancer after high-grade serous adenocarcinomas. CCC tends to develop resistance to the standard platinum-based chemotherapy, and has a poor prognosis when diagnosed in advanced stages. The ANXA4 gene, along with its product, a Ca⁺⁺-binding annexin A4 (ANXA4) protein, has been identified as the CCC signature gene. We reported two subtypes of ANXA4 with different isoelectric points (IEPs) that are upregulated in CCC cell lines. Although several in vitro investigations have shown ANXA4 to be involved in cancer cell proliferation, chemoresistance, and migration, these studies were generally based on its overexpression in cells other than CCC. To elucidate the function of the ANXA4 in CCC cells, we established CCC cell lines whose ANXA4 expressions are stably knocked down. Two parental cells were used: OVTOKO contains almost exclusively an acidic subtype of ANXA4, and OVISE contains predominantly a basic subtype but also a detectable acidic subtype. ANXA4 knockdown (KO) resulted in significant growth retardation and greater sensitivity to carboplatin in OVTOKO cells. ANXA4-KO caused significant loss of migration and invasion capability in OVISE cells, but this effect was not seen in OVTOKO cells. We failed to find the cause of the different IEPs of ANXA4, but confirmed that the two subtypes are found in clinical CCC samples in ratios that vary by patient. Further investigation to clarify the mechanism that produces the subtypes is needed to clarify the function of ANXA4 in CCC, and might allow stratification and improved treatment strategies for patients with CCC.     

alpha-Selective glycosylation with 5-thioglucopyranosyl donors; synthesis of an isomaltotetraoside mimic composed of 5-thioglucopyranose units

A general method for alpha-selective glycosylation with 5-thioglucopyranosyl donors followed by efficient deprotection of the resulting products was developed. This methodology was utilized in the synthesis of an isomaltotetraoside analogue.     

Possible role of adrenomedullin in the regulation of Fontan circulation: mature form of plasma adrenomedullin is extracted in the lung in patients with Fontan procedure

OBJECTIVE: We investigated the pathophysiological significance of molecular forms of adrenomedullin (AM) in patients after the Fontan procedure. METHODS: Plasma concentrations of mature AM (AM-m), an active form, glycine-extended AM (AM-Gly), an inactive form, and total AM (AM-T: AM-m+AM-Gly) were measured by specific immunoradiometric assay in the femoral vein, pulmonary artery and femoral artery of 29 consecutive patients after the Fontan procedure. The eleven patients who had history of Kawasaki disease and have normal coronary and hemodynamics served as control. RESULTS: Patients who underwent Fontan procedure had significantly higher venous concentrations of AM-T, AM-Gly, and AM-m than age-matched normal controls (AM-T, 12.0+/-3.3 vs. 9.6+/-2.0; AM-Gly, 10.4+/-3.0 vs. 8.5+/-1.6; AM-m, 1.6+/-0.7 vs. 1.0+/-0.6 pmol/l, each p<0.05). In patients with Fontan procedure, there were no differences in plasma AM-T, AM-Gly or AM-m levels between the femoral vein and pulmonary artery, however, there was a significant step-down in the AM-m levels, but not in plasma AM-T or AM-Gly levels, between the pulmonary artery and femoral artery (1.3+/-0.6 to 1.0+/-0.6, p<0.05). The venous concentrations of AM-m correlated negatively with systemic blood flow (cardiac output) (r=-0.46, p<0.05). CONCLUSIONS: Results suggest that in Fontan circulation plasma AM-m is increased in parallel with those of AM-T and AM-Gly and that AM-m is extracted in the lung. Extracted AM-m may be involved in the regulation of pulmonary arterial tonus, although further studies are necessary to elucidate the exact role of AM in Fontan circulation.     

Stimulation of the biosynthesis of the antibiotics lambertellols by the mycoparasitic fungus Lambertella corni-maris under the acidic conditions produced by its host fungus in vitro

The filamentous fungus, Lambertella corni-maris (L. corni-maris), a mycoparasite on Monilinia fructigena, produces the antibiotics, lambertellols A (1), B (2), and lambertellin (3), in a substantial amounts under acidic conditions, whereas these antibiotics were hardly detected when the fungus was cultured on a potato-sucrose (PS) medium without added acids. Our investigations also revealed that the host, M. fructigena, changed its surroundings into acidic conditions, suggesting that the acidic conditions acted as kairomones that stimulated the production of 1-3.     

Synthetic studies on oligosaccharides composed of 5-thioglucopyranose units

Glycosylation reactions of 5-thioglucopyranosyl trichloroacetimidates bearing ethereal protective groups at the 2-O-position 14-15, and 37 proceed smoothly to give alpha-glycosides stereoselectively by using a catalytic amount of silyl triflate. This methodology allowed us to achieve syntheses of sulfur-substituted isomaltotetraoside 2 and maltotetraoside 3. These studies also revealed that benzoyl-protected 5-thioglucopyranosyl trichloroacetimidate 12 underwent beta-selective glycosylation with C6-OH glucopyranosyl acceptors upon activation by BF3OEt2. This was applied for preparation of sulfur-substituted gentiobiosides 1 and 46.