Objective To explore the significance and value of the anti-nucleosome antibodies(AnuA)in the diagnosis of system-ic lupus erythematosus(SLE).Methods The serum AnuA was detected in 177 patients with SLE,138 patients with other rheumat-ic diseases and 56 healthy controls by Western blot.The clinical manifestations,autoantibodies and other test results were recorded in the SLE patients.The AnuA and other autoantibodies were analyzed.Results The positive rate of AnuA in the SLE group was significantly higher than that in the disease control group,AnuA was negative in the healthy control group;the sensitivity of AnuA in the SLE group was 48.6% and the specificity was 95.3%;the sensitivity of AnuA was significantly higher than that of the anti-ds-DNA antibodies and anti-Sm antibodies,the difference had statistical significance (P <0.05).The specificity of AnuA was higher than that of ANA and histone (P <0.05 ).The sensitivity of joint detection of AnuA,anti-ds-DNA and anti-Sm antibodies was 89.8%,which was significantly higher than that of a single index detection.The positive rate of AnuA in the active period of SLE was significantly higher than that of the non-active period,moreover higher than that of the ds-DNA antibodies (P <0.05).Conclu-sion AnuA might participate in the pathogenesis of SLE.The joint detection of autoantibodies including AnuA,etc.has importance significance in the diagnosis,condition judgment and curative efficacy evaluation of SLE.

Pyran- and furanocoumarins are key representatives of tetrahydropyrans and tetrahydrofurans, respectively, exhibiting diverse physiological and medical bioactivities. However, the biosynthetic mechanisms for their core structures remain poorly understood. Here we combined multiomics analyses of biosynthetic enzymes in Peucedanum praeruptorum and in vitro functional verification and identified two types of key enzymes critical for pyran and furan ring biosynthesis in plants. These included three distinct P. praeruptorum prenyltransferases (PpPT1-3) responsible for the prenylation of the simple coumarin skeleton 7 into linear or angular precursors, and two novel CYP450 cyclases (PpDC and PpOC) crucial for the cyclization of the linear/angular precursors into either tetrahydropyran or tetrahydrofuran scaffolds. Biochemical analyses of cyclases indicated that acid/base-assisted epoxide ring opening contributed to the enzyme-catalyzed tetrahydropyran and tetrahydrofuran ring refactoring. The possible acid/base-assisted catalytic mechanisms of the identified cyclases were theoretically investigated and assessed using site-specific mutagenesis. We identified two possible acidic amino acids Glu303 in PpDC and Asp301 in PpOC as vital in the catalytic process. This study provides new enzymatic tools in the epoxide formation/epoxide-opening mediated cascade reaction and exemplifies how plants become chemically diverse in terms of enzyme function and catalytic process.