Toxicity and Molecular Identification of Green Toadfish Lagocephalus lunaris Collected from Kyushu Coast, Japan

Green toadfish Lagocephalus lunaris inhabits tropical and subtropical seas and contains high tetrodotoxin (TTX) levels in the muscle as well as liver and gonad. In 2008 to 2009, food poisoning due to ingesting L. lunais occurred in Western Japan. Five specimens of green toadfish caught in Kyushu coast, Japan, were analyzed for toxicity, toxins, and species identification. All five specimens were toxic by bioassay. Comparing the maximum toxicity in tissues, ovary contained the most toxin (1810 mouse unit [MU]/g), followed by liver (341 MU/g), muscle (135 MU/g), skin (79 MU/g), and intestine (72 MU/g). Liquid chromatography/mass spectrometry analysis revealed that TTX was the major toxin. Nucleotide sequence analysis of the 16S rRNA gene fragment of muscle mitochondrial DNA indicated that partial sequences of PCR products of four specimens were identical with that of L. lunaris. The sequence of one specimen was indistinguishable from that of the brown-backed toadfish Lagocephalus wheeleri, a nontoxic species

ホタテガイの中腸腺由来金属結合タンパク質の分離

Marine bivalves accumulate high concentrations of potentially toxic heavy metals in their tissues. We report here our investigation of the accumulation patterns of cadmium (Cd), copper (Cu), and lead (Pb) in tissues of the Japanese scallop Mizuhopecten yessoensis after exposure to artificial seawater containing Cd, Cu, or Pb. Our results revealed that accumulation of these heavy metals by this scallop was associated with certain intracellular metal-binding proteins (MBPs). Cd was accumulated at higher concentrations than Cu and Pb, and most of the accumulated metals were detected in the digestive gland. MBPs from the digestive gland were purified and subjected to a preliminary characterization. Three proteins with molecular masses of approximately 28, 37, and 42 kDa, respectively, were isolated by gel-filtration and anion-exchange column chromatography. Characterization of the partial amino acid sequences of these proteins show high sequence similarity to MBPs and ion-transporters. Metalloprotein profiles in the digestive gland indicated that some proteins were upregulated after metal exposure, suggesting that these proteins are involved in mechanisms of metal accumulation and detoxification in M. yessoensis.ホタテガイをカドミウム，銅または鉛を含む人工海水に暴露した後，金属の蓄積能および金属結合タンパク質の存在を調べた。いずれの金属も中腸腺に顕著に蓄積され，その蓄積量はカドミウム，銅，鉛の順に高かった。中腸腺から分子量約 28, 37 および 42 kDa の金属結合タンパク質が精製され，これらのアミノ酸部分配列解析により，Coccidioides immitis の calcium-binding protein または Pleurocapsa sp. の ion-transporter 類似タンパク質と高い相同性を示すことを明らかにした。これらのタンパク質はホタテガイの金属蓄積または解毒メカニズムに関与していることが示唆された

メイラード反応により修飾した魚肉水溶性タンパク質の機能性に及ぼすグルコース-6-リン酸比率の影響

東京水産大学食品加工学研究室東京水産大学食品加工学研究室東京水産大学食品加工学研究

ポリリジンの抗菌性に及ぼすメイラード反応の影響

東京水産大学食品製造学講座東京水産大学食品製造学講座東京水産大学食品製造学講

細菌の接種によって誘導されるアコヤガイ中の抗菌性タンパク質の探索

The aim of this research was to characterize immune-related antibacterial substances from pearl oyster Pinctada fucata induced by bacterial invasion. Bacteria inoculation was performed by injecting 0.1 ml of 1.0 × 1012 colony-forming units/ml Vibrio parahaemolyticus into adductor muscle. Acidic extracts were prepared with 0.1% trifluoroacetic acid from different tissues after 8 h of injection, and antibacterial activity against V. parahaemolyticus was determined via the microdilution broth method. The acidic extracts from gills of inoculated oysters (AEg) showed stronger antibacterial activity than those from non-inoculated ones. Based on this result, antibacterial proteins were purified from AEg via two-step gel filtration chromatography, followed by high-performance liquid chromatography using a TSkgel G3000 column. Protein components were analyzed by both sodium dodecyl sulfate and native polyacrylamide gel electrophoresis. As a result, two antibacterial proteins, APg-1 (with a molecular mass of approximately 210 kDa) and APg-2 (of approximately 30 kDa), were obtained from AEg. Matrix-assisted laser desorption/ionization time of flight mass spectrometry analysis and partial amino acid sequences revealed that these proteins might be novel antibacterial proteins. These results indicate that antibacterial proteins are potentially upregulated in the gill of pearl oysters or released therefrom for defense against bacterial invasion.本研究で対象とするアコヤガイは，日本において重要な養殖真珠の母貝として用いられる二枚貝である。腸炎ビブリオをアコヤガイ閉殻筋に直接接種したところ，鰓から得られた酸抽出物に，非接種の対照よりも強い抗菌活性を示す成分が存在することを見出した。酸抽出物はグラム陽性菌および陰性菌に抗菌活性を示し，とくにビブリオ属に強く作用した。鰓より2種の抗菌タンパク質APg-1（分子量約210 kDa）およびAPg-2（分子量約30 kDa）を分離し，これらはMALDI-TOF MS分析により，新規の抗菌タンパク質である可能性が推察された

魚肉水溶性タンパク質から調製した可食性フィルムの水蒸気透過性におよぼす脂質添加の影響

東京水産大学食品生産学科東京水産大学食品生産学科東京水産大学食品生産学科東京水産大学食品生産学

Detection and management of cardiomyopathy in female dystrophinopathy carriers

Regular health checkups for mothers of patients with Duchenne muscular dystrophy have been performed at National Hospital Organization Tokushima Hospital since 1994. Among 43 mothers participated in this study, 28 dystrophinopathy carriers were identified. Skeletal and cardiac muscle functions of these subjects were examined. High serum creatine kinase was found in 23 subjects (82.1%). Obvious muscle weakness was present in 5 (17.8%) and had progressed from 1994 to 2015. Cardiomyopathy was observed in 15 subjects (60.0%), including dilated cardiomyopathy-like damage that was more common in the left ventricular (LV) posterior wall. Late gadolinium enhancement on cardiac MRI was found in 5 of 6 subjects, suggesting fibrotic cardiac muscle. In speckle tracking echocardiography performed seven years later, global longitudinal strain was decreased in these subjects, indicating LV myocardial contractile abnormality. These results suggest that female dystrophinopathy carriers should receive regular checkups for detection and treatment of cardiomyopathy, even if they have no cardiac symptoms