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Polysaccharides prepared from the red alga Chondrus verrucosus (Rhodophyta, Gigartinales) were subjected to anion-exchange column chromatography, and the chemical characteristics of the fractions (designated CV1, CV2 and CV3 in the order of elution) were examined based on carbohydrate and sulfate contents and monosaccharide composition. Furthermore, the anti-inflammatory effect of the fractions on the degranulation in RBL-2H3 cells stimulated by A23187 was investigated. The results showed that the major monosaccharide component was galactose. The CV1 and CV2 fractions showed higher anti-inflammatory activity against RBL-2H3 cells than the CV3 fraction. The difference in activity may be related to the sulfate contents, namely, the contents of CV1, CV2 and CV3 fractions were 25.3 ± 3.3%, 28.1 ± 1.1%, and 7.4 ± 1.8%, respectively.

Ecological stoichiometry suggests that herbivore growth is limited by phosphorus when this element in the diet is 300). However, in nature, it is not necessarily related to the relative phosphorus content in diets. This may be the result of complex feeding and assimilation responses to diets. We examined these possibilities using herbivorous plankton fed mono-specific and mixed algae varying in phosphorus content of 1.6 to 8.1 μg P mg C-1 . The herbivores showed a 10-fold growth rate difference among the diets. Growth rates related poorly with phosphorus content in the diets (r2 = 0.07), better with P ingestion rate (r2 = 0.41) and best with phosphorus assimilation rate (r2 = 0.69). Inclusion of assimilation rates for carbon and fatty acids increased 7% of the explained growth variance. These results indicate that the feeding and assimilation flexibilities play pivotal roles in acquiring a deficient element and in regulating growth rate.

Fish are exposed to many kinds of environmental stressors and the chances of succumbing to infectious diseases may be increased a result. For example, an acute increase in temperature can induce numerous physiological changes in the body. In the present study, we examined the redox state in response to a severe acute stress resulting from heat shock in teleost coho salmon (Oncorhynchus kisutch). The plasma lipid peroxides levels in fish gradually increased after heat shock treatment. By 2.5 h post-heat stress, plasma glutathione (GSH) levels had decreased, but they had returned to basal levels by 17.5 h post-stress. Plasma superoxide dismutase activities in stressed fish were significantly increased compared with those in control fish at 17.5 h post-stress, but had returned to basal levels by 48 h post-stress. Expression levels of hepatic GSH and heat shock protein 70 gradually increased after heat shock treatment. These results concerning the changing patterns of multiple important redox-related biomarkers suggest that severe thermal stressors can affect the redox state and induce oxidative stress in ectothermal animals, such as fish, in vivo. Hence, manipulation of appropriate thermal treatment may possibly be useful to control fish fitness., Graphical abstract, Highlights • The plasma lipid peroxides levels gradually increased after heat shock. • The plasma glutathione levels had decreased, but they had returned to basal levels. • The plasma superoxide dismutase activities were increased. • The hepatic glutathione and heat shock protein 70 levels gradually increased. • Severe thermal stressors can affect the redox state and might induce oxidative stress.

We investigated the potential for exploiting Stevia rebaudiana stem (SRS) waste as a source of edible plant-based antioxidants finding for the first time that the hot water extract of SRS had significantly higher antioxidant activity against fish oil oxidation than that of the leaf, despite SRS extract having lower total phenolic content, DPPH radical scavenging activity and ORAC values. To locate the major antioxidant ingredients, SRS extract was fractionated using liquid chromatography. Five phenolic compounds (primary antioxidant components in activity-containing fractions) were identified by NMR and HR-ESI-MS: vanillic acid 4-O-β-d-glucopyranoside (1), protocatechuic acid (2), caffeic acid (3), chlorogenic acid (4) and cryptochlorogenic acid (5). Further analysis showed that, among compounds 2-5, protocatechuic acid had the highest capacity to inhibit peroxides formation, but exhibited the lowest antioxidant activities in DPPH and ORAC assays. These results indicate that SRS waste can be used as strong natural antioxidant materials in the food industry.

We established a simple, rapid method for gizzerosine analysis in fish meal. Gizzerosine was extracted from fish meal with 0.1 N HCl solution. Samples and standard gizzerosine solutions were absorbed onto a paper disc, which was then set on electrophoresis paper for 18 min, and the paper was dried. Gizzerosine was visualized with Pauly’s reagent, and the intensity of the colored spots was digitized and calculated by image processing method software. We achieved successful separation of gizzerosine from other Pauly’s reagent-positive components in fish meal extracts. The linearity of gizzerosine estimation using this method was within the range 30–1000 ng (R 2 = 0.99). Gizzerosine was satisfactorily detected and completely separated from histamine and other Pauly’s reagent-positive compounds. This method does not require expensive instruments or tedious pretreatment to eliminate interfering compounds, such as histamine or histidine. It also uses less reagent compared with high-performance liquid chromatography. Moreover, it is a simple, rapid, sensitive, and reproducible method. It is suitable for monitoring gizzerosine in fish meal products that contain as little as 10 ppm gizzerosine.

A simple and rapid thin-layer chromatography (TLC)-densitometry method for histamine analysis in fish and fishery products was established. Histamine was extracted from seafood with 80% ethanol. The sample extracts and standard solutions of histamine were applied to cellulose TLC plate and developed by ascending chromatography with ammonia–ethanol 1:3 ( v/v ) as mobile phase. Histamine was visualized with pauly’s reagent, the intensity of the colored spots was digitized and calculated by image processing method software, Lane & Spot Analyzer (ATTO, Tokyo, Japan). Successful separation of histamine from other (imidazole compounds) pauly’s reagent-positive components in 80% ethanol fish extracts was achieved. The linearity of the histamine estimation using this method was good within the range from 30 ng to 1000 ng of histamine ( r 2 = 0.9997). Histamine can be satisfactorily detected and completely separated from histidine, 4-methyl-imidazole and other pauly’s reagent-positive compounds. This method does not need expensive instrument, any tedious pretreatment to eliminate potential interference other imidazole compounds such as histidine or carnosine. It is also less reagents compared with HPLC method. Moreover, it is a simple, rapid, sensitive, reproducible. Therefore this method is suitable for monitor of histamine in multiple fish and fishery products simultaneously that contain as little as 20 ppm histamine (2.0 mg/100 g).

Angiotensin-I-converting enzyme (ACE) plays a crucial role in the crisis of hypertension. Some peptides that originate from protease hydrolysates are known to suppress ACE activity in vitro and in vivo. Here, we investigated whether trypsin hydrolysate of oyster Crassostrea gigas showed hypotensive activity and ACE inhibition. The hydrolysate significantly suppressed systolic blood pressure and ACE activity in spontaneously hypertensive rats following a one-shot oral administration and a long-term feeding experiment lasting 9 weeks. Each hydrolysate from oyster tissue showed ACE inhibitory activity, indicating the hypotensive effect was due to synergism. One potent ACE inhibitory peptide, Asp-Leu-Thr-Asp-Tyr, was identified from the hydrolysate of the striate muscle, and the peptide exhibited hypotensive activity in vivo. Protease digestion analysis suggested that Asp-Tyr could be the real effector of this penta-peptide in vivo.

The simple and rapid detection of histamine-forming bacteria (HFB) was achieved using a newly developed filtration method. In this method not only liquid samples including seawater, but also seafood, can be assayed on-site. Liquid samples were filtered through a two-layer filtration system with an upper 10-μm pore size membrane filter (φ 25 mm) and lower 0.2-μm pore size, spherical membrane filter (φ 25 mm). In the case of seafood, samples were minced with nine volumes (v/w) of sterilized saline solution in aseptic conditions, and the homogenates and their dilutions were filtered through the two-layer system. The two-layer membrane filter was then rinsed with 10 ml sterilized saline solution. The lower membrane filter was placed on an artificial seawater agar medium plate (pH 5.8), containing histidine (0.5%) as a carbon source and bromothymol blue (0.04%) as a pH indicator, and incubated at 35 °C. HFB were detected as blue halo colonies on the lower membrane filter after 5 h of incubation. The color change in agar medium is attributed to the alkaline shift following histamine formation by HFB. Histamine-producing ability for colonies with a blue halo was confirmed by prolonged incubation in histidine broth medium at 35 °C for 24 h. This simple filtration method can rapidly detect HFB and can be applied to food hygiene systems, including the hazard analysis and control critical point (HACCP) system in seafood processing lines.

This study investigates the formation and accumulation of histamine in the fresh meat of tuna fish. Under sterilized conditions, histamine was not detected in the muscles of Thunnus obesus (T. obesus) stored at 20 °C and 25 °C for 72 h (data not shown). And histamine formation and the diffusion mechanism was studied in T. obesus meat inoculated with two histamine-forming bacteria, Morganella morganii NBRC 3168 (M. morganii NBRC 3168) and Photobacterium phosphoreum NBRC 13896 (P. phosphoreum NBRC 13896) and stored at 20 °C and 25 °C for 3 days. The histamine level of the inoculated A1 point accumulated at a level above 4000 mg/kg in the T. obesus sample inoculated with M. morganii NBRC 3168 for 48 h. And the most level of the histamine in the remote B point was 2000 mg/kg at the time the sample was inoculated with M. morganii NBRC 3168 and stored at 25 °C. For the P. phosphoreum NBRC 13896 however, the level of histamine at the inoculated point A was 1800 mg/kg for 48 h when it was stored at 25 °C, while the highest level of histamine distant from the inoculum site B point was found to be approximately 1800 mg/kg. In contrast, when stored at 20 °C, histamine level was higher for the sample inoculated with P. phosphoreum NBRC 13896 than with M. morganii NBRC 3168. While histamine was diffused from the inoculation point in the M. morganii NBRC 3168 sample, it was diffused not only from the inoculated point, but also the remote area in the P. phosphoreum NBRC 13896 sample.

Growth in fish is regulated by the growth hormone (GH)-growth hormone receptor (GHR)-insulin-like growth factor-1 (IGF-1) axis. However, the effect of severe acute stressors on the GH-IGF-1 axis in fish is not well understood. The present study determined the changes in mRNA expression of growth-related genes gh, ghr, and igf and the redox state in coho salmon (Oncorhynchus kisutch), in response to severe acute stress. Severe stress consisted of exposure to heat shock (adequate rearing temperature +11 °C for 2 h). The plasma expression patterns of redox state-related biomarkers, such as glutathione, lipid peroxides, and superoxide dismutase, in response to heat shock suggest that heat shock might induce oxidative stress in fish. After exposure to heat shock, ghr mRNA levels in the pituitary glands and liver increased, whereas levels decreased 48 h post-stress. Hepatic igf1 mRNA expression levels gradually decreased in response to the stressor. On the other hand, the pituitary gh mRNA expression did not change in response to the stressor. These findings showed that a heat shock-induced oxidative stress could affect the redox state and the expression of several growth-related genes in coho salmon. The results of this study also suggest that the expression of several growth-related genes in fish may be affected differently by the types and strength of stress.

The described analytical method for histamine determination in fish and seafood consists of sample extraction, adsorption onto a paper disc, application of the paper disc onto electrophoresis paper, electrophoresis for only 10 min, drying, and color developing by Pauly’s reagent. Histamine can be satisfactorily detected and completely separated from histidine, carnosine and other Pauly reagent-positive compounds. This method does not require expensive instrumentation and any tedious pretreatment to eliminate potential interference by other imidazole compounds, such as histidine or carnosine. This method can be used to detect histamine in multiple fish and seafood samples simultaneously that contain as little as 15 p.p.m. histamine (1.5 mg/100 g).

The effects of a hot water extract of the stem of Stevia rebaudiana on the smooth muscle of isolated guinea pig ileum were investigated. The butyl alcohol layer of the extract antagonized the contractions of the isolated guinea pig ileum induced by histamine (1 x 10(-5) M) and acetylcholine (1 x 10(-5) M) in a concentration-dependent manner. The butyl alcohol layer of the extract also showed inhibition of CaCl(2) (1 x 10(-3)-3.8 x 10(-1) M)-induced contractions. The antagonism of the extract was considered to be non-specific, but this action might be related to an influx of extracellular Ca(2+). With column chromatography preparation, the active component was assumed to be as stevioside. The antagonistic effects exerted by the stem extract of Stevia rebaudiana contributed to the gastroprotective activity of the extract in animals fed dietary histamine.

In this paper, the authors report the detection of alanine racemase activity in the marine diatom Thalassiosira sp. Since the Thalassiosira sp. was cultured under germ-free conditions, it appeared that D-alanine was not derived from bacteria but was produced through catalysis by algal alanine racemase. The rate of conversion of L-alanine to D-alanine was approximately the same as that for the reverse reaction, and the enzyme catalyzed the equilibration of the D- and L-forms. The crude enzyme preparation obtained from the cells at the stationary phase of the growth cycle had an optimal pH of approximately 9.5. The Lineweaver—Burk analysis showed that the K m for D- and L-alanine was 16.5 mM and 29.4 mM, respectively. It appears that the enzyme is highly specific for D- or L-alanine because it does not catalyze the racemization of other amino acids. In addition, after gel filtration, the enzyme did not require exogenous pyridoxal 5′-phosphate (PLP) for its activity, however, the effects of several chemicals suggest that the enzyme may be PLP-dependent. The enzyme is more similar to that found in invertebrates when compared with that found in bacteria. This is the first report on the occurrence of alanine racemase activity in the microalga Thalassiosira sp.

The complete complementary DNA sequences of genes presumably coding for opine dehydrogenases from Arabella iricolor (sandworm), Haliotis discus hannai (abalone), and Patinopecten yessoensis (scallop) were determined, and partial cDNA sequences were derived for Meretrix lusoria (Japanese hard clam) and Spisula sachalinensis (Sakhalin surf clam). The primers ODH-9F and ODH-11R proved useful for amplifying the sequences for opine dehydrogenases from the 4 mollusk species investigated in this study. The sequence of the sandworm was obtained using primers constructed from the amino acid sequence of tauropine dehydrogenase, the main opine dehydrogenase in A. iricolor. The complete cDNA sequence of A. iricolor, H. discus hannai, and P. yessoensis encode 397, 400, and 405 amino acids, respectively. All sequences were aligned and compared with published databank sequences of Loligo opalescens, Loligo vulgaris (squid), Sepia officinalis (cuttlefish), and Pecten maximus (scallop). As expected, a high level of homology was observed for the cDNA from closely related species, such as for cephalopods or scallops, whereas cDNA from the other species showed lower-level homologies. A similar trend was observed when the deduced amino acid sequences were compared. Furthermore, alignment of these sequences revealed some structural motifs that are possibly related to the binding sites of the substrates. The phylogenetic trees derived from the nucleotide and amino acid sequences were consistent with the classification of species resulting from classical taxonomic analyses.

Stevia extract was made from stevia stem by extraction with boiling water and fermentation. The protective effect of a Stevia extract on rainbow trout (average weight, 12 g) fed 1% of dietary histamine for 4 weeks was investigated. Administration of dietary histamine to trout did not result in a reduction in growth rate or feed consumption but caused a gastric abnormality, e.g. exfoliation of the mucosal epithelium and atrophy of mucosal lamina propria. Stevia extract protected gastric tissue from histamine-induced damage. Pepsin activity in gastric fluid increased and liver alpha-tocopherol content was reduced after histamine treatment, but Stevia treatment prevented these abnormalities. The results suggest that the stevia extract might protect the rainbow trout stomach from histamine toxicity.

The present study's aim was to investigate change of fatty acid composition of white adipose tissue with increasing age in Syrian hamster fed continuously alfalfa (LU) or cereal based diet (F2). A total of 43 Syrian hamsters with male and female, 22 head maintained with mating between sibling in a close herd fed F2 (GN) and 21 head selected for long-term for large number of weaning pups per a mater using GN fed LU (ALF), were used. Fatty acid composition in adipose tissues taken from the back leg subcutaneous depot, periphery of kidney and reproductive organs at 3, 8 and 13 weeks of age were determined by using a gas chromatograph. Carbon (C)18:0 in GN tended to decrease and C18:1 increased significantly with increasing age, suggesting that Δ9-desaturase had related adaptively. C18:3 in ALF increased significantly with increasing age. The present results indicate that, although the composition in unsaturated fatty acid (USFA) in both herds was different, the ratio of USFA to saturated fatty acid increased with increasing age suggesting that USFA in GN fed F2 was at a high level compared with in ALF fed LU.

Information on the metabolism of exogenous histamine in fish is of much concern regarding the effect of dietary histamine on fish. Histamine catabolic enzymes, diamine oxidase and histamine N-methyl transferase were measured in the tissues of rainbow trout. Diamine oxidase was detected in the stomach, pylorus caeca and intestine. Histamine N-methyl transferase was detected only in the liver. A change in the contents of histamine and its metabolites was observed in the tissues of rainbow trout after oral administration of histamine. A large amount of imidazole acetic acid was observed in the serum, kidney, liver and muscle. On the other hand, 1-methyl histamine was detected only in the liver. Histamine and its metabolites, imidazole acetic acid and 1-methyl histamine were metabolized and diminished within 48 hr in all tissues. These results showed that histamine was metabolized by two metabolic routes in rainbow trout. One is the main pathway producing imidazole acetic acid by intestinal diamine oxidase and the other is the complementary pathway producing 1-methyl histamine by liver N-methyl-transferase.

The color of wheat flour is an important commercial factor and improvement of the color characteristics of kernels is one of the breeding objectives in Japan. Methods were developed to measure color characteristics of both wheat kernels and wheat flour. Wheat kernels were fixed on a newly developed holder with light-curing resin, and a smooth cut-surface was prepared by a programmed cutting of a diamond wheel. Binder-free wheat flour was formed into cylindrical pellets to remove trapped air by repeated compression with a hydraulic press machine. Cut kernels and flour pellets were moistened and analyzed by a two-dimensional colorimetric method. Color changes of both specimens were stabilized after 3 h of moistening. And a comparison of their colorimetric results revealed the possibility of evaluating wheat flour color without milling the kernels. This is useful as an early generation selection method of breeding of wheat because the dissected embryo side retains the germination ability.

Seven kinds of angiotensin I-converting enzyme (ACE) inhibitory peptides were isolated from the hydrolysates of wakame (Undaria pinnatifida) by Protease S "Amano" (from Bacillus stearothermophilus) by using three-step high-performance liquid chromatography (HPLC) on a reverse-phase column. These peptides were identified by amino acid composition analysis, sequence analysis, and liquid chromatography-mass spectrometry (LC-MS), as Val-Tyr (IC(50) = 35.2 microM), Ile-Tyr (6.1 microM), Ala-Trp (18.8 microM), Phe-Tyr (42.3 microM), Val-Trp (3.3 microM), Ile-Trp (1.5 microM), and Leu-Trp (23.6 microM). These peptides have resistance against gastrointestinal proteases in vitro. Each peptide was determined to have an antihypertensive effect after a single oral administration in spontaneously hypertensive rats (SHR). Among them, the blood pressure significantly decreased by Val-Tyr, Ile-Tyr, Phe-Tyr, and Ile-Trp in a dose of 1 mg/kg of body weight (BW). The present study showed that antihypertensive effect in the hydrolysates of wakame by Protease S "Amano" was attributed to these peptides.

To study the genetic aspects of fatty acid components in adipose tissues of Syrian Hamsters, a total of ninety animals of three lines were used. One inbred line (GN) was always fed cereals (Diet F) and inbred to the closed herd. Another selected line (ALF) was always fed with alfalfa meal pellet (Diet A) and selected to increase the weaning number. Another control line (GNR) was mated at random, with one of its group always fed cereals without selecting for litter size, and the second group fed an alfalfa pellet. Adipose tissues were taken from three parts of the subcutaneous round of back legs, round of kidney and generative organs. Rates of fatty acid components of total lipids extracted from their tissues were determined by Gas Chromatography and compared statistically to average out random effects of the line, sex, age in weeks, body part and diet. To research for genetic variation of fatty acid components and Δ9-desaturase activity index (Δ9-desat.), genetic parameters of each effect were estimated.ALF seems to increase the animal's productive ability of C18:1, a measure of the efficiency of biosynthesis for mono-unsaturated fatty acids(MUSFA). So, ALF might be introducing a genetic variation by increasing the capacity to make use of energy in reproductive behavior. Estimated heritabilities of MUSFA and Δ9-desat. were 0.73 and 0.61 respectively. Estimated genetic correlation between total saturated fatty acid(SFA) and MUSFA or Δ9-desat. were negative values. Considering the circumstances mentioned above, amounts of fatty acid components in adipose tissues of every part might be induced to genetically. To determine that, it might be useful to use Δ9-desat. as an indicator.

Aim: The angiotensin-I-converting enzyme (ACE) inhibitory and antihypertensive activities of wakame hydrolysates have been investigated in several studies. Methods: Wakame (Undaria pinnatifida) was hydrolyzed using 17 kinds of proteases and the inhibitory activity of the hydrolysates for ACE was measured. Of these hydrolysates 4 with potent ACE inhibitory activity were administered singly and orally to spontaneously hypertensive rats (SHR). Results: The systolic blood pressure of SHR decreased significantly after single oral administration of protease S ‘Amano’ and proleather FG-F hydrolysates (10 mg protein/kg body weight). In a long-term feeding experiment, 7-week-old SHR were fed standard chow supplemented with protease S ‘Amano’-derived wakame hydrolysates for 10 weeks. In SHR fed the 1 and 0.1% wakame hydrolysates, elevation of systolic blood pressure was still significantly suppressed for 7 weeks. Conclusions: The hydrolysates derived from wakame by protease S ‘Amano’ have a powerful ACE-inhibitory activity (IC50 = 86 µg protein/ml) and were effective in spite of their slight bitterness as ‘physiologically functional food’ with antihypertensive activity.

Histamine content was investigated in some fresh scombroid fish including tuna ( Thunnus spp), mackerel ( Scomber Japonicus ) etc, and non-scombroid fish including mahi–mahi ( Coryphaena hippurus ), sardine ( Sardina pilchardus ), herring ( Clupea harengus ) etc, and fish products (sauce, dried fish) which came from Fiji, Germany, the Netherlands, Norway, Thailand, Cambodia, the Philippines, Japan and China. Histamine was detected in 35 of the 159 fish samples tested for a detection rate of about 21%. Fish samples exceeding 50 ppm histamine occurred in about 9% of the samples with 5 samples exceeding 500 ppm of which 2 were above 1000 ppm. Fish sold in markets in some countries may cause a histamine risk to consumers while other countries may have the necessary controls in place.

An experiment was conducted to determine if dietary Stevia (Stevia rebaudiana) extract prevents gizzard erosion and ulceration of chicks induced by dietary histamine. Day old broiler chicks were fed on a basal diet, a diet with 0.4% histamine or a diet containing 0.2% Stevia extract (on dry matter basis) +0.4% histamine for 14 days. Dietary histamine reduced growth and caused occurrence of gizzard erosion and ulceration as previously reported. Feeding of Stevia extract containing diet partly prevented retardation of growth and occurrence of gizzard erosion and ulceration caused by histamine. The result shows that the Stevia extract contains active substance(s) that attenuates histaminic action.

The study revealed the presence of plasmalogens in the low density lipoprotein (LDL) and high density lipoprotein (HDL) of the fish. The composition of the plasmalogen in the carp plasma LDL phospholipids was 0.94 and 0.23% in the HDL; the LDL phospholipids in the rainbow trout were 0.44% and the HDL was 0.18%. Aldehydes from the plasmalogen were derivatized with dansylhydrazides and separated by high performance liquid chromatography (HPLC). Their presence was detected using a fluorescence detector. Hexadecanal (C16: 0), octadecanal (C18: 0) and octadecenal (C18: 1) were determined to be the major components in the carp and rainbow trout.

SUMMARY: Changes in distribution of dietary α-tocopherol at 100 mg per 100 g of diet to organic tissues and to serum lipoproteins were investigated on Japanese flounder Paralichthys olivaceus. α-tocopherol had been transported to and preserved more positively in the gonad during the reproduction period. During maturity serum α-tocopherol had partly combined with the vitellogenin-like parts that diminished after the spawning period. Conversely, serum α-tocopherol after the spawning period partly combined with lipoprotein that increased after the spawning period. The prosperity and decline of different types of lipoproteins induced α-tocopherol distribution changes at the end of the spawning period.

ステビア茎粗抽出物は強い抗酸化活性を示した.その活性は抗酸化指数で葉に比べ5倍程度高く,現在ほとんど利用されていない茎の新たな利用価値を提示した.ステビア抽出末はマイワシ油およびリノール酸に対して100ppmの添加で抗酸化効果を発現した.その効果は同濃度のBHT,α-Tocに匹敵する強さを示した.ステビア抽出末はα-Tocおよびクエン酸を併用することにより抗酸化効果が増強された.ステビア抽出末の抗酸化有効成分は主として透析外液(分画分子量500)に存在した.外液濃縮物を逆相カラムクロマトグラフィー.薄層クロマトグラフィーで分画し,複数の有効画分を認めた.その多くは,ポリフェノール化合物であったが,最も強い効果を示した成分にはカリウムが高濃度で存在した.

ステビア抽出末に強い抗酸化活性を認め,その活性の最も強い画分には高濃度のカリウムの存在が認められたことから,カリウム塩を含む9種類の無機塩の抗酸化効果を調べた.その結果,K2CO3,KHCO3,Na3PO4,Na2CO3およびKClにリノール酸に対する抗酸化効果を認めた.NaCl,CaCl2,MgCl2およびMgSO4には抗酸化効果は認められなかった.K2CO3は60ppm(カリウム濃度として)以上の濃度で抗酸化効果を示し,最も強力であった.α-Tocと併用することでその効果は向上したが,クエン酸とでは向上は認められなかった.ステビア抽出末の抗酸化作用機構について,フリーラジカル捕捉効果,スーパーオキシド捕捉効果および金属キレート作用について調べた.ステビア抽出末の抗酸化効果は主としてフリーラジカルの捕捉効果に因るもので,スーパーオキシドの消去能も補足的に関わっているものと考えられた.

魚類において脂質が魚体のある部分に偏在することを利用し,脂質含量の測定に画像解析の技術を適用することを試みた.アユ,マイワシおよびサンマの横断切片を試料とした.試料の入力方法として転写法,非染色切片および染色切片の直接法あるいは写真法を採用した.画像解析は,入力画像の雑音除去,階調値分布の解析後,階調変換により二値化処理を行い,試料断面の脂肪組織の画素数を計測し,試料断面全体の画素数に対すその比から脂質含量を求めた.すべての魚種の画像測定においてB成分を採用した.画像解析法により求めた脂質含量を同切片を溶媒抽出して得られた脂質含量と比較した.養殖アユの写真法において非染色切片で相関係数0.981,染色切片で0.980と高い相関が認められた.また,マイワシおよびサンマの非染色切片における写真法および直接法においても比較的高い相関が得られた.これらのことから,脂肪組織と筋肉組織を比較的明瞭に区別できるアユおよびマイワシなどの魚種において,画像解析方法は脂質含量の迅速かつ簡便な評価方法になるものと考えられた.

The biosynthetic pathway of 5Z, 8Z, 11Z, 14Z, 18Z-eicosapentaenoic acid (EPA, C20: 5n-3) in Vibrio sp. isolated from sea urchin was studied. EPA was one of the major fatty acid constituents (17.5%) in the bacteria, while the other polyunsaturated fatty acids were trace elements (

1. 魚油の酸化により発生する臭いを熱線型半導体式ガスセンサーであるニオイセンサーにより測定する条件について検討した.2. 今回設定した測定条件によればニオイセンサーにより求めたニオイ濃度値は魚油の酸化程度の指標として用いることができることを明らかにした.3. 本法が抗酸化剤の効果の評価の際に応用できることを示した.

A time-series sediment trap was deployed in a shallow lagoon, Saroma Ko, from 9 December 1986 to 2 May 1987. During the ice-covered period (mid-January to mid-April) total mass fluxes (dry weight) were lower than 2 gm^ day^, while after mid-April the flux increased to more than 11 gm^ day^. The dominant sterol associated with sinking particles throughout the observation period was cholesterol most of which were possibly from animal-derived sources such as scallop feces. During the ice-covered period, sterols mostly were derived from marine animals, although the sterol abundance was low in quantity. The period of phytoplankton bloom below the ice (mid-March to mid-April) did not respond to that of the maximum flux (after mid-April), but coincided with that of the occurrence of phytoplankton-derived sterols. During the ice-free periods (before mid-January and after mid-April), sinking particle sources are variable, and bottom sediment- and land-derived (mostly terrestrial plants) sterols are larger in quantity than those during the ice-covered periods, primarily because of the active water movements in the lagoon.

The angiotensin-I-converting enzyme (ACE) inhibitory and antihypertensive activities of wakame hydrolysates have been investigated in several studies.Wakame (Undaria pinnatifida) was hydrolyzed using 17 kinds of proteases and the inhibitory activity of the hydrolysates for ACE was measured. Of these hydrolysates 4 with potent ACE inhibitory activity were administered singly and orally to spontaneously hypertensive rats (SHR).The systolic blood pressure of SHR decreased significantly after single oral administration of protease S 'Amano' and proleather FG-F hydrolysates (10 mg protein/kg body weight). In a long-term feeding experiment, 7-week-old SHR were fed standard chow supplemented with protease S 'Amano'-derived wakame hydrolysates for 10 weeks. In SHR fed the 1 and 0.1% wakame hydrolysates, elevation of systolic blood pressure was still significantly suppressed for 7 weeks.The hydrolysates derived from wakame by protease S 'Amano' have a powerful ACE-inhibitory activity (IC(50) = 86 microg protein/ml) and were effective in spite of their slight bitterness as 'physiologically functional food' with antihypertensive activity.

Lipid and fatty acid compositions of cultured and wild coho salmon were compared. Tri-glyceride (TG) was the main component of lipids in all the tissues investigated. TG contents of ordinary and dark muscles (ca. 90%) were higher than those of liver, gonad and viscera (50-70%). The main fatty acids of cultured fish were C16:0, C18:1, C20.3 and C22:6, while those of wild fish were C16:0, C18:1, C20:1, C22:1 and C22:6. The fatty acids such as C20:1 and C22:1 were higher in wild fish than in cultured fish. Monoenoic fatty acids were the main components of fatty acids in ordinary muscle, dark muscle, viscera, integument, head and bone, and testis. Polyenoic fatty acids were higher in liver and ovary than in the other tissues.