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The Iowa (G26R) mutation in human apolipoprotein A‐I (apoA‐I), the major protein of plasma high‐density lipoprotein, is associated with systemic amyloidosis, and the N‐terminal 1–83 fragment of apoA‐I carrying this mutation has a strong propensity to form amyloid fibrils. Here, we generated and characterized novel monoclonal antibodies (mAbs) that display selective reactivity to apoA‐I amyloid fibrils. By immunizing BALB/c and A/J mice with apoA‐I 1‒83/G26R fibrils conjugated with hemocyanin and the hybridoma production, four IgM class mAbs were obtained. The generated mAbs exhibited strong reactivity to amyloid fibrils formed by the 1–83 fragment of apoA‐I, but not to the monomeric 1–83 fragment or full‐length apoA‐I. The apparent dissociation constant of the mAbs to apoA‐I fibrils was determined to be within the nM range. A time‐dependent aggregation assay demonstrated that the mAbs preferentially react with mature fibrils over non‐fibrillar aggregates formed by apoA‐I 1–83/G26R. In addition, dot blotting and ELISA using deletion or proline substituted variants of apoA‐I 1‒83/G26R suggest that the generated mAbs react to common structural features in apoA‐I amyloid fibrils. Indeed, the mAbs also recognized amyloid fibrils formed by α‐synuclein that has no sequence identity to apoA‐I. Thus, our newly generated anti‐apoA‐I fibril mAbs may be utilized for not only diagnosis of apoA‐I‐related amyloidosis but also structural analysis of amyloid fibrils as novel conformation‐selective antibodies. [ABSTRACT FROM AUTHOR]

Possible pathways for the pyrolysis of resorcinol with the formation of CO and CO 2 as final products were proposed and evaluated using ab initio calculations. Our experimental study revealed that large quantities of CO 2 are generated in the pyrolysis of 1,3-dihydroxybenzene (resorcinol), while the pyrolysis of the dihydroxybenzene isomers 1,2-dihydroxybenzene (catechol) and 1,4-dihydroxybenzene (hydroquinone) produces little CO 2 . The fate of oxygen atoms in catechol and hydroquinone was essentially the formation of CO. In the proposed pathways, the triplet ground state m-benzoquinone was generated initially from simultaneous cleavage of the two O-H bonds in resorcinol. Subsequently, the direct cleavage of a C-C bond of the m-benzoquinone diradical yields 2-oxidanylcyclopenta-2,4-dien-1-yl-methanone, which can be converted via two channels: release of CO from the aldehyde radical group and combination of the ketone radical and carbon atom in the aldehyde radical group to form the 6-oxabicyclo[3.2.0]hepta-2,4-dien-7-one, resulting in the release of CO 2 . Potential energy surfaces along the proposed reaction pathways were calculated employing the CBS-QB3 method, and the rate constants at the high-pressure limit were also evaluated based on transition-state theory to assess the feasibility of the proposed reaction pathways.