The Schizosaccharomyces pombe cdc6 gene encodes the catalytic subunit of DNA polymerase δ

The cdc6 mutants of Schizosaccharomyces pombe have been classified as being defective in progression through the G2 phase of the cell cycle. We cloned an S. pombe gene that could complement the temperature-sensitive growth of the cdc6-23 mutant. Unexpectedly, the cloned gene was allelic to pol3, which encodes the catalytic subunit of DNA polymerase δ. Integration mapping confirmed that cdc6 and pol3 are identical. The cdc6-23 mutant carries one amino acid substitution in the conserved N3 region of Pol3. Received: 17 October 1996 / Accepted: 19 November 1996     

Two oligosaccharides from Marsdenia roylei

Phytochemical analysis of dried twigs of Marsdenia roylei (family Asclepiadaceae) has resulted in the isolation of a trisaccharide, maryal, and a diglycoside, rolinose. Their structures were determined as O-beta-D-oleandropyranosyl-(1-->4)-O-beta-D-digitoxopyranosyl++ +-(1-->4)-D- cymaral and ethyl O-beta-D-oleandropyranosyl-(1-->4)-O-3-O-methyl-6-deoxy-beta-D- allopyranoside, respectively, by chemical degradation and spectroscopic methods.     

Targeting Interleukin-6: All the Way to Treat Autoimmune and Inflammatory Diseases

Interleukin (IL)-6, a cytokine featuring redundancy and pleiotropic activity, contributes to host defense against acute environmental stress, while dysregulated persistent IL-6 production has been demonstrated to play a pathological role in various autoimmune and chronic inflammatory diseases. Targeting IL-6 is thus a rational approach to the treatment of these diseases. Indeed, clinical trials of tocilizumab, a humanized anti-IL-6 receptor antibody have verified its efficacy and tolerable safety for patients with rheumatoid arthritis, Castleman''s disease and systemic juvenile idiopathic arthritis, resulting in approval of this innovative biologic for treatment of these diseases. Moreover, a considerable number of case reports and pilot studies of off-label use of tocilizumab point to the beneficial effects of tocilizumab for a variety of other phenotypically different autoimmune and chronic inflammatory diseases. Elucidation of the source of IL-6 and of mechanisms through which IL-6 production is dysregulated can thus be expected to lead to clarification of the pathogenesis of various diseases.     

溶血磷脂酸在皮肤损伤疾病中的作用及其分子机制

皮肤作为人体最大器官覆盖于全身,能阻挡有害物质的侵入,保护人体内环境稳态,参与人体代谢过程。皮肤损伤、炎症和纤维化等,都会导致皮肤屏障功能的减退,影响正常的生命活动。溶血磷脂酸(lysophosphatidic acid,LPA)是十分活跃的磷脂信号分子,参与多种生理和病理生理过程。LPA是维持体内平衡所必需的生物活性脂质介质,在皮肤中通过不同的信号通路发挥多功能磷脂信使作用。本文综述了皮肤中溶血磷脂酸受体(lysophosphatidic acid receptor,LPA1-6)及其细胞信号通路的作用及机制,综述了LPA在皮肤创面愈合、皮肤瘢痕、皮肤黑色素瘤、硬皮病、皮肤瘙痒、过敏性皮炎、皮肤屏障、皮肤疼痛,皮肤毛发生长中的作用及分子机制,有助于了解LPA在皮肤中的生理和病理生理作用。深入研究LPA的作用机制将有助于挖掘其在皮肤治疗中的作用,开发以LPA为靶点的药物。     

Discovery of novel phenoxazinone derivatives as DKK1/LRP6 interaction inhibitors: Synthesis,biological evaluation and structure–activity relationships

Amino derivatives of NCI8642 were synthesized and evaluated as inhibitors of DKK1/LRP6 interactions. The new inhibitors were able to activate the Wnt signaling pathway as indicated by the increased levels of β-catenin, and decrease the DKK1-induced Tau phosphorylation at serine 396.     

The Amount of BCL6 in B Cells Shortly after Antigen Engagement Determines Their Representation in Subsequent Germinal Centers

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Determination of 8-oxoguanine in human plasma and urine by high-performance liquid chromatography with electrochemical detection

A highly sensitive and selective method for determining 8-oxoguanine in plasma and urine was developed by high-performance liquid chromatography with electrochemical detection. The compound was separated by gradient elution on a C₁₈ reversed-phase column with a mobile phase of acetonitrile and 0.1 M sodium acetate, pH 5.2. 8-Hydroxy-2′-deoxyguanosine was used as internal standard. 8-Oxoguanine was detected electrochemically by setting the potential to +300 mV vs. Pd reference. The sensitivity of the assay was 22 ng/ml with a signal-to-noise ratio of 7:1. The within-day relative standard deviations for 8-oxoguanine quality control samples with concentrations of 3340, 1340 and 84 ng/ml were 3.6, 4.3 and 5.7% for plasma, and 4.1, 4.6 and 6.2% for urine, respectively. The day-to-day relative standard deviations for the same samples were 3.8, 6.8 and 7.1% for plasma, and 3.9, 7.0 and 7.9% for urine, respectively. The method is designed to study the pharmacokinetics and metabolic fate of O⁶-benzylguanine in a phase I clinical trial. Previously, O⁶-benzyl-8-oxoguanine was identified as the primary metabolite of O⁶-benzylguanine in humans. We now demonstrate that 8-oxoguanine is a further metabolite of O⁶-benzylguanine.     

Probing binding mechanism of interleukin-6 and olokizumab: in silico design of potential lead antibodies for autoimmune and inflammatory diseases

Computer-aided antibody engineering has been successful in the design of new biologics for disease diagnosis and therapeutic interventions. Interleukin-6 (IL-6), a well-recognized drug target for various autoimmune and inflammatory diseases such as rheumatoid arthritis, multiple sclerosis, and psoriasis, was investigated in silico to design potential lead antibodies. Here, crystal structure of IL-6 along with monoclonal antibody olokizumab was explored to predict antigen–antibody (Ag???Ab)-interacting residues using DiscoTope, Paratome, and PyMOL. Tyr56, Tyr103 in heavy chain and Gly30, Ile31 in light chain of olokizumab were mutated with residues Ser, Thr, Tyr, Trp, and Phe. A set of 899 mutant macromolecules were designed, and binding affinity of these macromolecules to IL-6 was evaluated through Ag???Ab docking (ZDOCK, ClusPro, and Rosetta server), binding free-energy calculations using Molecular Mechanics/Poisson Boltzman Surface Area (MM/PBSA) method, and interaction energy estimation. In comparison to olokizumab, eight newly designed theoretical antibodies demonstrated better result in all assessments. Therefore, these newly designed macromolecules were proposed as potential lead antibodies to serve as a therapeutics option for IL-6-mediated diseases.     

Gap Junctions Mediate Glucose Transport Between GLUT1-Positive and -Negative Cells in the Spiral Limbus of the Rat Cochlea

To elucidate the role of the spiral limbus in glucose transport in the cochlea, we analyzed the expression and localization of GLUT1, connexin26, connexin30, and occludin in the spiral limbus of the rat cochlea. GLUT1 and occludin were detected in blood vessels. GLUT1, connexin26, connexin30, and occludin were also expressed in fibrocytes just basal to the supralimbal lining cells. Connexin26 and connexin30 were present among not only these GLUT1-positive fibrocytes but also GLUT1-negative fibrocytes. In vivo glucose imaging using 6-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino]-6-deoxyglucose (6-NBDG, MW 342) together with Evans Blue Albumin (EBA, MW 68,000) showed that 6-NBDG was rapidly distributed throughout the spiral limbus, whereas EBA was localized only in the vessels. Moreover, the gap junctional uncoupler heptanol inhibited the distribution of 6-NBDG. These findings suggest that gap junctions play an important role in glucose transport in the spiral limbus, i.e., that gap junctions mediate glucose transport from GLUT1-positive fibrocytes to GLUT1-negative fibrocytes in the spiral limbus.     

Trichome-borne and artificially applied acylsugars of wild tomato deter feeding and oviposition of the leafminer Liriomyza trifolii

Oviposition and adult feeding of the leafminer Liriomyza trifollii (Burgess) (Diptera, Agromyzidae) on Lycopersicon pennellii (Corr.) D'Arcy and its F₁ hybrid with Lycopersicon esculentum (Mill.) was significantly less than that on the cultivated tomato, L. esculentum. The resistance of L. pennellii and the F₁ was reduced following rinsing of foliage with ethanol. Resistant attributes of L. pennellii were transferred to L. esculentum through appression of L. pennellii foliage to L. esculentum leaflets. Application of purified 2,3,4-tri-O-acylglucoses (the principal component of type IV glandular trichome exudate of L. pennellii) to L. esculentum significantly decreased feeding and oviposition on L. esculentum leaflets by 61–99%. Therefore the principal mechanism of resistance to this leafminer by L. pennellii is the secretion of these acylglucoses. Dose response analysis of acylglucoses applied to L. esculentum shows that dosages as low as 10% those found on L. pennellii provide large reductions (91%) in leaf punctures and mines.