タモギタケから単離したエルゴチオネインの生体内抗酸化性に関する研究

We investigated the serum antioxidative activity in the hepatic portal vein at 5, 15, 30, 60, and 90 minutes after the injection of 0.1% ergothioneine into the small intestine of rats using Oxygen Radical Absorbance Capacity (ORAC). Furthermore, we attempted to identify ergothioneine in the rat serum by electric spray ionization liquid chromatography mass spectrometry (ESI-LC-MS). No changes were observed in the ORAC values from the hepatic portal vein of rats administered and those not administered ergothioneine. Further, no molecular ion peaks were observed in the rat serum by the ESI-LC-MS

タモギタケから単離したエルゴチオネインの加熱および各pHにおける抗酸化性への影響

エルゴチオネインの抗酸化性について加熱温度および各pHの影響をORAC分析法で調べた。1) タモギタケから得た精製エルゴチオネインは、ORAC法においてグルタチオン、L-システイン、L-メチオニンなどのチオール基含有アミノ酸および含硫アミノ酸と比べ抗酸化活性が高かった。DPPHラジカル消去活性評価法による測定においても同様の結果を示した。2) 精製したエルゴチオネインおよびエルゴチオネインを含む抽出物は、加熱温度や各pHで抗酸化性が変わらず、安定的に抗酸化能を有する化合物であることが、ORAC法において確認された。We investigated the effects of heat and pH on the antioxidative activity of ergothioneine from Pleurotus cornucopiae using Oxygen Radical Absorbance Capacity (ORAC) and DPPH radical scavenging activity methods. The ORAC assayed showed that ergothioneine maintained high antioxidative activity at 25, 40, 60, 80, and 100℃. Proportional decreases in the antioxidative activity of L-ascorbic acid and garlic acid were observed with increases in temperature. L-ascorbic acid, in particular, showed a large reduction in ORAC value, with the antioxidative activity at 100℃ only 23% that at 25℃. Ergothioneine and garlic acid showed high antioxidative activity for 7 days under acidic or neutral conditions (pH 3.0, pH 5.0, and pH 7.0). Furthermore, ergothioneine maintained its antioxidative activity for 7 days under neutral and alkali conditions (pH 7.2 and pH 9.0), whereas that of garlic acid decreased to about 70% at day 3. The antioxidative activity of L-ascorbic acid decreased at every pH as time increased. From these results, it appears that ergothioneine is an excellent antioxidant on which heat and pH have little effect. Further, we found that ergothioneine has the highest level of antioxidative activity of the four amino acids tested (ergothioneine, glutathione, L-methionine and L-cysteine)

Storage Proteins

Plants accumulate storage substances such as starch, lipids and proteins in certain phases of development. Storage proteins accumulate in both vegetative and reproductive tissues and serve as a reservoir to be used in later stages of plant development. The accumulation of storage protein is thus beneficial for the survival of plants. Storage proteins are also an important source of dietary plant proteins. Here, we summarize the genome organization and regulation of gene expression of storage protein genes in Arabidopsis

A large outbreak of enterohaemorrhagic Escherichia coli O157, caused by low-salt pickled Napa cabbage in nursing homes, Japan, 2012

Objective: In August 2012, an outbreak of enterohaemorrhagic Escherichia coli (EHEC) O157 infection was investigated by the City of Sapporo and Hokkaido Prefectural Government. The initial notification reported an illness affecting 94 residents of 10 private nursing homes distributed across multiple areas of Hokkaido, the northernmost island of Japan; at this time three cases were confirmed as EHEC O157 infection. The objectives of the investigation were to identify the source of infection and recommend control measures to prevent further illness. Methods: A suspected case was defined as a resident of one of the private nursing homes in Hokkaido who had at least one of the following gastrointestinal symptoms: diarrhoea, bloody stool, abdominal pain or vomiting between 10 July and 10 September 2012. Cases were confirmed by the presence of Shiga toxin 1- and 2-producing EHEC O157 in stool samples of suspected cases. We conducted an epidemiological analysis and an environmental investigation. Results: We identified 54 confirmed and 53 suspected cases in 12 private nursing homes including five fatalities. Of the 107 cases, 102 (95%) had consumed pickles, all of which had been manufactured at the same facility. EHEC O157 isolates from two pickle samples, 11 cases and two staff members of the processing company were indistinguishable. The company that produced the pickles used inadequate techniques to wash and sanitize the vegetables. Discussion: Contaminated pickles were the likely source of this outbreak. We recommended that the processing company improve their methods of washing and sanitizing raw vegetables. As a result of this outbreak, the sanitation requirements for processing pickles were revised