Effect of iron-quercetin complex on reduction of nitrite in in vitro and in vivo systems

This study investigated whether reducing agents such as quercetin and iron(II) facilitate formation of nitric oxide (NO) gas from orally ingested nitrite in an vivo study. When 3 mg/kg Na (15)NO2 was orally administered to rats with or without iron(II) or quercetin, Hb (15)NO, which is indicative of systemic (15)NO, was detected in the blood, with the maximum blood concentration of Hb (15)NO at 15 min after nitrite or nitrite plus quercetin treatment, whereas after administration of nitrite plus iron(II) or nitrite plus iron(II) and quercetin, the time was shortened to 10 min. Interestingly, iron(II), quercetin, or iron(II) plus quercetin did not affect the total amount of Hb (15)NO generated from orally administered Na (15)NO2. However, the systemic nitrite concentration was significantly decreased in the presence of iron(II) or iron(II) plus quercetin. These results may indicate that iron(II) is critical to the generation of NO gas from nitrite, whereas quercetin contributed little under the in vivo experimental conditions.     

Antioxidative activity and antidiscoloration efficacy of ergothioneine in mushroom (Flammulina velutipes) extract added to beef and fish meats

The antioxidative property of a hydrophilic extract prepared from the fruiting body of edible mushroom ( Flammulina velutipes) was evaluated. The mushroom extract contained ergothioneine (ERT) at a level of 3.03 +/- 0.07 mg/mL, showed higher 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, and suppressed lipid oxidation of bigeye tuna meat more effectively than authentic L-ERT added at the same concentration. The authentic L-ERT had stronger total reducing power than the mushroom extract and inhibited the formation of metmyoglobin (metMb) more significantly in bigeye tuna meat. Lipid oxidation in beef and fish meats to which the mushroom extract had been added was "virtually" controlled during storage on ice. Ground beef and bigeye tuna meat with the extract added kept their natural colors unchanged for longer than 12 and 7 days of ice storage, respectively. Contrary to this, browning in meat color was observed in the control samples without the extract after 6 and 2 days of storage, respectively, when stored under similar conditions. There was significant correlation between meat color and chemical parameters, including total lipid hydroperoxides, thiobarbituric acid reactive substances, and metMb. However, there was no significant correlation between pH value and meat discoloration. These results suggest that ERT in the hydrophilic extract of F. velutipes plays an important role as a color stabilizer of meats.     

Ontogenetic habitat shift in abalone <Emphasis Type="Italic">Haliotis discus hannai</Emphasis>: a review

Ecological literature on abalone Haliotis discus hannai populations is reviewed to identify processes and factors driving ontogenetic shifts in habitat. Abalone recruitment is related to the algal community type, with abalone shifting with growth from deeper crustose coralline algal (CCA) habitats to shallower kelp bed habitats via algal turfs. Timing of the habitat shifts is linked to ontogenetic changes in diet, from benthic diatoms to a diet dominated by macroalgae. Susceptibility to predation appears to change, concomitant with the shift from cryptic microhabitats during early-life stages to more exposed habitats during latter-life stages. Interstitial spaces between cobbles and boulders in the CCA habitat are considered to be important for reducing predation risk. The loss of CCA nursery habitat through sedimentation and macroalgal overgrowth likely negatively affects abalone recruitment. Preservation of diverse algal communities, including suitable habitats for the different abalone growth stages, is critical for successful abalone recruitment.     

Stage-specific distribution of Japanese sea cucumber <Emphasis Type="Italic">Apostichopus japonicus</Emphasis> in Maizuru Bay,Sea of Japan,in relation to environmental factors

The Japanese sea cucumber Apostichopus japonicus plays important ecological and economic roles in the coastal areas of Japan. Here, we aim to reveal the relation between habitat characteristics and density of juvenile and adult sea cucumbers in Maizuru Bay. Density of adult sea cucumbers was estimated by underwater visual surveys and bottom trawls and that of newly settled individuals by seedling collectors distributed in the bay. The physical environment of the sea bottom was evaluated from median diameter, total organic carbon, total nitrogen, carbon-to-nitrogen ratio, carbon isotope ratio, nitrogen isotope ratio, depth, slope, and distance from the coastline. Adult sea cucumber density was higher in the east side than the west side of Maizuru Bay, the former having a no-take zone for sea cucumbers. Juvenile sea cucumbers were most abundantly collected in the central part of the bay. High organic matter from the sea, short distance from the coastline, and high seabed gradient (steepness) had a positive effect on the density of adult sea cucumbers, and depth had positive effects on their body size. We suggest that sustainable management of sea cucumbers can be achieved by a combination of the establishment of no-take zones and increased protection of nursery habitats.     

Synthesis and insecticidal activity of nitroguanidine derivatives

Nitroguanidine derivatives with thiazol-5-ylmethyl moieties were prepared and their insecticidal activities against homopterous pests were tested. New synthetic routes for 2-chloro-5-chloromethylthiazole from 2,3-dichloro-1-propene and for substituted nitroguanidines from S-methyl-N-nitroisothiourea were established. Biological evaluation led to a novel insecticide (E)-1-(2-chlorothiazol-5-ylmethyl)-3-methyl-2-nitroguani dine (TI-435) which has a broad activity spectrum and is under development. ©1999 Society of Chemical Industry     

Evaluation of the Modifying Effect of Inhalation of Mainstream Cigarette Smoke on Mouse Bladder Carcinogenesis

Cigarette smoking is one of the major risk factors of bladder cancer in humans. To date, however, there is no experimental evidence for the effects of inhalation exposure to mainstream cigarette smoke on bladder carcinogenesis. The purpose of the present study was to evaluate the effect of inhalation of mainstream cigarette smoke on mouse bladder carcinogenesis using a cigarette smoke inhalation exposure system. Six-week-old male C57BL mice were administered 0.025% N-butyl-N-(4-hydroxybutyl) nitrosamine (BBN) in their drinking water for 8 weeks and then divided into 2 groups and exposed to 0 or 300 mg/m³ wet total particulate matter mainstream cigarette smoke for 2 h per day, five times per week, for 22 weeks. The incidences of bladder tumors (papilloma and urothelial carcinoma) tended to increase in the cigarette smoke-exposed group (25.0%) compared with the controls (15.8%), albeit without a statistically significant difference. We also evaluated mRNA expression levels of cytochrome P450 (cyp) enzymes and proliferating cell nuclear antigen (PCNA) in the bladder epithelium. Expression of cyp1a1 was significantly increased in the cigarette smoke-exposed group. Cigarette smoke exposure did not have a significant effect on the expression of cyp1a2, cyp 1b1, cyp 2a4, cyp 2b10, cyp 2e1, or PCNA. In conclusion, limited exposure to mainstream cigarette smoke for 22 weeks, caused a significant increase in cyp1a1 expression. This increase coupled with the nonsignificant increase in bladder tumors suggests that a longer period of exposure is required to clarify the effects of cigarette smoke on bladder carcinogenesis.     

Accumulation of gamma-oryzanol in teleost

Japanese people consume crop bran, which contains relatively high amounts of gamma-oryzanol (ORZ), as foodstuffs and food materials. We have recently confirmed that ORZ inhibits NF-κB activation, activates peroxisome proliferator-activated receptor gamma (PPARγ), and increases plasma adiponectin levels. ORZ is therefore expected to improve lipid and carbohydrate metabolisms and various inflammatory diseases, i.e., metabolic syndrome including type 2 diabetes. ORZ administration also allowed fish, such as rainbow trout, yellowtail, and red sea bream, to accumulate protein through enhancement of lipid and carbohydrate metabolisms. In the present study, we have investigated ORZ accumulation levels in mouse and rainbow trout administered ORZ-containing feed. Although mouse muscle and liver hardly contained ORZ, muscle tissues of every fish species accumulated higher amounts of ORZ. These findings suggest that rainbow trout, red sea bream, and yellowtail accumulate ORZ in muscle.     

The first success of glass eel production in the world: basic biology on fish reproduction advances new applied technology in aquaculture

The eel has long been esteemed as an important food fish in the world, especially in Japan, and has been used as an experimental fish for many fields of fish physiology. However, the decreases in eel resources have been a serious concern in recent years. The catches of glass eels as seedlings for aquaculture have shown a long-term decrease in both Europe and East Asia. To increase eel resources, the development of techniques for artificial induction of maturation and spawning and rearing their larvae have been eagerly desired. Recent progress of reproductive physiology of fish, especially mechanisms of oocyte maturation and ovulation in female and of spermatozoa maturation in male, facilitate to establish techniques for hormonal induction of maturation and spawning in sexually immature eels. With persistent effort to development of rearing techniques of larvae, we have first succeeded to produce glass eel. These applied techniques are may contribute to understand the basic reproductive physiology of the eel.     

Thermal gelation properties of white croaker, walleye pollack and deepsea bonefish surimi after suwari treatment at various temperatures

The effects of setting (suwari) at around 40 °C on the breaking strength and breaking strain rate of thermal gels treated at 85 °C for 20 min during the following processing step were examined in association with the polymerization and degradation of myosin heavy chains (MHCs) for surimi prepared from white croaker, walleye pollack and deepsea bonefish. In the case of white croaker and walleye pollack, maximum values of breaking strength and breaking strain rate were obtained after suwari at 30–40 °C for both 30 and 60 min, at which temperature MHCs were polymerized. In comparison, these textual properties of the thermal gels decreased in surimi prepared from deepsea bonefish after suwari at around 38 °C for 30 min and at around 32 °C for 60 min, with concomitant degradation products of MHC. The textual properties of deepsea bonefish after suwari at temperatures >45 °C tended to be almost the same as those after suwari at temperatures of <30 °C, where neither polymerization nor degradation of MHC was observed.     

Distribution of adipocyte-related cells in skeletal muscle of rainbow trout Oncorhynchus mykiss

Adiponectin is one of the adipokines secreted mainly from adipocytes in mammals. In rainbow trout, however, adiponectin is highly expressed in skeletal muscle. Although it has been suggested that fish skeletal muscle contains adipocytes, their endocrine function and distribution are poorly understood. Recently, an EST analysis of rainbow trout found that heart-type fatty acid binding protein (H-FABP), a member of the intracellular fatty acid binding protein family, encodes an adipose-specific gene. In this study, we produced anti-adiponectin and H-FABP antibodies and investigated the distribution of adipocytes and related cells in skeletal muscle of rainbow trout. The adiponectin signal was detected at around 75 kDa in muscle in Western blotting. Since the molecular mass of rainbow trout adiponectin is around 25 kDa, this 75 kDa band would be a trimer. For H-FABP, the signal band was detected at around 15 kDa. Immunohistochemistry of skeletal muscle sections indicated that adiponectin and H-FABP signals were present outside of muscle cells and throughout the muscle tissues, suggesting the existence of adipocyte-related cells in these regions. These results will contribute to our understanding of energy metabolism in fish skeletal muscle.