Action of Pyrroloquinolinequinol As an Antioxidant Against Lipid Peroxidation in Solution

This is the publisher's version, also available electronically from: http://online.liebertpub.com/doi/pdfplus/10.1089/ars.1999.1.4-547.The activities of pyrroloquinoline quinone (PQQ), a coenzyme of methanol dehydrogenase and amine oxidase, and its reduced form pyrroloquinoline quinol (PQQH2 ) as an antioxidant have been measured in solution. PQQH2 was stable in the absence of oxygen but rapidly auto-oxidized to PQQ in the presence of oxygen in water. PQQH2 was stable in an aprotic solvent such as acetonitrile, even in air. PQQ did not exert appreciable antioxidant activity, whereas PQQH2 exerted higher reactivity than a-tocopherol toward galvinoxyl radical and peroxyl radical. PQQH2 acted as a potent antioxidant against the oxidation of methyl linoleate in acetonitrile induced by azo compound and produced a clear induction period, from which the apparent stoichiometric number was obtained as 1.1. PQQH2 reduced the a-tocopheroxyl radical and spared a-tocopherol in the oxidation of methyl linoleate. These results suggest that PQQH2 may act as a potent antioxidant, particularly in combination with a-tocopherol. Antiox. Redox Signal. 1, 547-554

ポリヒドロキシ ラクサン ジュウテン ドジョウ カラム リアクター ノ ダツチツノウ ト サイキン グンシュウ カイセキ

Denitrification activity behavior and bacterial community structure in a poly-β-hydroxybutyrate (PHB) embedded soil-column reactor were investigated. The influent containing nitrate (NO3-N) was applied in a downward flow. The NO3-N concentration rapidly decreased only in the middle part of the column where PHB was embedded, which indicated that the denitrification activity in the reactor was related to PHB. Influent NO3-N was effectively removed in the reactor following 60 days of continuous operation. The total number of bacteria in the lower and middle parts of the column decreased after 30 days, and then increased again after 60 days; however, the number in the upper part continuously decreased with time. The number of PHB utilizing denitrifiers increased in both the middle and lower parts with time, contributing to denitrification activity in the reactor. From the result of PCR and denaturing gradient gel electrophoresis (PCR-DGGE), the presence of two denitrifing and a few other bacteria were determined, and which suggested of Ralstonia related species played an important role in the denitrification capability of the reactor.生分解性プラスチックの一つであるポリヒドロキシ乳酸 (PHB) を充填した下降流式土壌カラムリアクター内での硝酸脱窒挙動と、それに関与する土壌中の細菌叢を解析した。PHBが充填されているリアクター中部では、リアクターの運転開始60日後に硝酸性窒素 (以下NO3-Nと略す) 除去率が98%以上となり、それ以降も安定した硝酸除去がみられたのに対し、電子供与体の供給が乏しい上部でのNO3-N除去率は75日経過時においても約15%にとどまった。また、リアクター中部と下部の土壌では、全菌数および脱窒菌数がともに経時的に増加した。以上の結果から本リアクターのNO3-N除去能がPHBを電子供与体や炭素源として利用する脱窒細菌によるものであることが明らかとなった。さらに、16S rDNAのPCR-DGGEによる細菌叢解析結果から、5種類以上の細菌の存在が示され、中でもNO3-N還元能を有するRalstonia pickettiiに近縁な細菌が、主に本リアクターのNO3-N脱窒能に寄与しているものと推定された