Identification and kinetic study of tyrosinase inhibitors found in sake lees     

Jeon HJ  Noda M  Maruyama M  Matoba Y  Kumagai T  Sugiyama M 《Journal of agricultural and food chemistry》2006,54(26):9827-9833

The present study found that the n-hexane extract of freeze-dried sake lees inhibits tyrosinase activity and showed that the constituents isolated from the n-hexane extract are the mixture of triacylglycerols. The inhibitory effects of triolein and trilinolein found as the triacylglycerols were examined using tyrosinases from mushroom and Streptomyces castaneoglobisporus. The IC50 values of the triacylglycerol mixture for the oxidase activity on mushroom and Streptomyces tyrosinases were 20 and 0.14 microg/mL, respectively. The IC50 values of trilinolein for the oxidase activity on mushroom and Streptomyces tyrosinases were 8.4 and 0.1 microM, respectively. However, the inhibitory effect of triolein (IC50=30 microM) was lower than that of trilinolein, even when the Streptomyces tyrosinase was used for the assay. Kinetic analyses indicate that both trilinolein and triolein inhibit the tyrosinase activity noncompetitively. When transformed with a plasmid carrying the Streptomyces tyrosinase gene, the melanin-synthesizing ability of the transformed Escherichia coli host was dose-dependently interfered with by trilinolein.  相似文献   

Effects of sedimentation on an endangered benthic fish,Cobitis shikokuensis: is sediment‐free habitat a requirement or a preference?          下载免费PDF全文

Ryota Kawanishi  Ryota Dohi  Asuka Fujii  Mikio Inoue 《Ecology of Freshwater Fish》2015,24(4):584-590

A negative correlation between the degree of fine sediment deposition and the abundance of stream benthic fishes has often been reported, although the causal mechanisms for this effect are not fully understood. To better understand the influence of sedimentation, it is important to clarify whether it alters the habitat required by fish, or merely preferred by them. We conducted two enclosure experiments in the field to examine (i) whether an endangered benthic fish, Cobitis shikokuensis, prefers sediment‐free substrate and (ii) whether fine sediment deposition has negative effects on the physiological condition of C. shikokuensis. The first experiment, which used three types of substrates, ‘cobble’, ‘pebble’ and ‘mixture of fine sediment and pebbles’, showed that C. shikokuensis avoided the mixture. The second experiment, which compared the physiological condition of fish reared in enclosures with either a pebble or mixture substrate, showed that the condition of the fish in the latter group declined more quickly. These results suggest that, for C. shikokuensis, sediment‐free substrate is a habitat requirement, not merely a preference, and that excessive input of fine sediment due to human activities can cause a decline in the population of this species.  相似文献   

Glutathione supplementation to semen extender improves the quality of frozen-thawed canine spermatozoa for transcervical insemination     

Kazuko OGATA  Aiko SASAKI  Yuka KATO  Arisa TAKEDA  Mikio WAKABAYASHI  Borjigin SARENTONGLAGA  Mio YAMAGUCHI  Asuka HARA  Rika FUKUMORI  Yoshikazu NAGAO 《The Journal of reproduction and development》2015,61(2):116-122

The present study was conducted to evaluate whether supplementation of semen extender with glutathione (GSH) can maintain the quality of frozen-thawed canine spermatozoa. Eighteen ejaculates were obtained from 5 dogs and placed in extender (20% egg yolk, Tris, citric acid, lactose, raffinose, antibiotics and 6.5% glycerol) containing 0 (control), 2.5, 5, 7.5 or 10 mM GSH. The samples were cooled to 4 C and then frozen in liquid nitrogen vapor. Motility parameters of the sperm were evaluated at 0, 1, 2, 3, 4, 12 and 24 h after thawing. Sperm motility was higher in the 5 mM GSH group than in the control or 2.5 and 10 mM GSH groups; this effect was observed at 1 to 24 h after thawing (P < 0.05). The 5 mM GSH group had a higher sperm viability index at 12 and 24 h after thawing compared with the other groups (P < 0.05). Acrosome integrity, evaluated at 4 h after thawing, was greater in two of the GSH-treated groups (5 and 10 mM) compared with the control. Lipid peroxidation (LP) levels immediately after thawing were lower in the 5 and 10 mM GSH groups compared with the control, while those at 12 h after thawing did not differ significantly. Frozen-thawed semen in the 5 mM GSH group was used for transcervical insemination of 4 bitches, resulting in delivery of 5 puppies from 2 bitches. These results indicate that supplementation of semen extender with 5 mM GSH was effective in improving motility, longevity and acrosomal integrity and inhibiting LP levels in post-thaw canine spermatozoa, without any adverse impacts on full-term development after transcervical insemination.  相似文献   

Complementary effect of oral administration of Lactobacillus paracasei K71 on canine atopic dermatitis          下载免费PDF全文

Yuri Ohshima‐Terada  Yuki Higuchi  Takehisa Kumagai  Akihito Hagihara  Masahiko Nagata 《Veterinary dermatology》2015,26(5):350-e75

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Evaluation of total mixed ration silage with brewers grains for dairy buffalo in Tarai,Nepal          下载免费PDF全文

Takashi Sakai  Naba R. Devkota  Kazato Oishi  Hiroyuki Hirooka  Hajime Kumagai 《Animal Science Journal》2015,86(10):884-890

To investigate the effects of total mixed ration (TMR) silage, which contained brewers grain and rice straw as a substitute for conventional concentrate on feed intake and milk production in middle‐to‐late lactation buffaloes, four multiparous Murrah buffaloes were assigned to a 3 × 3 Latin square design experiment. The TMR silage, which had higher neutral and acid detergent fiber contents and digestibility than concentrate (P < 0.05) and similar crude protein (CP) and total digestible nutrient (TDN) contents with concentrate were used for the lactation experiment. The treatments were control (CTL) fed concentrate at 0.6% of body weight (BW), and T1 and T2 fed the TMR silage at 0.6 and 1.2% of BW on a dry matter (DM) basis, respectively, with rice straw ad libitum. Daily intakes of DM, CP and TDN, and BW change were higher in T2 than in CTL and T1 (P < 0.05). Although milk composition did not differ among the treatments, milk yield (MY) was higher in T2 (P < 0.05). There were no significant differences in MY/DM intake and MY/TDN intake among the treatments. The increase of BW and MY in middle‐to‐late lactation buffaloes might have been due to high TDN intake from supplementary TMR silage.  相似文献   

Very-long-period seismic signals and caldera formation at Miyake Island, Japan     

Kumagai H  Ohminato T  Nakano M  Ooi M  Kubo A  Inoue H  Oikawa J 《Science (New York, N.Y.)》2001,293(5530):687-690

Over a period of roughly 40 days, starting on 8 July 2000, a caldera structure 1.7 kilometers in diameter developed by means of gradual depression and expansion of the summit crater at Miyake Island, Japan. At the same time, very-long-period (VLP) seismic signals were observed once or twice a day. Source mechanism analyses of the VLP signals show that the moment tensor solutions are smooth step functions over a time scale of 50 seconds, with dominant volumetric change components. We developed a model to explain the caldera and the VLP signals, in which a vertical piston of solid materials in the conduit is intermittently sucked into the magma chamber by lateral magma outflow. This model offers potential for making quantitative estimations of the characteristic physical properties of magma systems.  相似文献   

Mercury pollution of fishes in Minamata Bay and surrounding water: Analysis of pathway of mercury     

Nishimura  Hajime  Kumagai  Mikio 《Water, air, and soil pollution》1983,20(4):401-411

Water, Air, & Soil Pollution - In 1973, the Environment Agency of Japan made an intensive survey of Hg pollution in Minamata Bay and its surrounding water. About 200 sediment samples and 1600...  相似文献   

Infrared spectroscopic evidence for protonated water clusters forming nanoscale cages     

Miyazaki M  Fujii A  Ebata T  Mikami N 《Science (New York, N.Y.)》2004,304(5674):1134-1137

Size-dependent development of the hydrogen bond network structure in large sized clusters of protonated water, H+(H2O)n (n = 4 to 27), was probed by infrared spectroscopy of OH stretches. Spectral changes with cluster size demonstrate that the chain structures at small sizes (n less, similar 10) develop into two-dimensional net structures (approximately 10 < n < 21), and then into nanometer-scaled cages (n >/= 21).  相似文献   

Life cycle greenhouse gas emissions of woodchip-paved walkways using tsunami salt-damaged wood: examination in Otsuchi,Iwate Prefecture     

Chihiro Kayo  Chiaki Watanabe  Takanobu Sasaki  Seiki Kumagai  Ryu Noda  Seiji Hashimoto 《Journal of Wood Science》2015,61(6):620-629

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Bovine oocytes in secondary follicles grow in medium containing bovine plasma after vitrification     

Taketsuru H  Takajo A  Bao RM  Hamawaki A  Yoshikawa M  Miyano T 《The Journal of reproduction and development》2011,57(1):99-106

There has been no culture system that supports the growth of bovine oocytes for more than 2 weeks. In the present study, bovine secondary follicles were cultured for 4 weeks, and the effects of supplemented protein components and FSH in the culture medium on the growth of the oocytes were examined. The effect of vitrification of secondary follicles on the subsequent oocyte growth was also examined. Secondary follicles (150 to 200 μm in diameter) containing growing oocytes (approximately 60 μm in diameter) were dissected from ovaries and cultured in a medium supplemented with FSH (0, 25 or 50 ng/ml) and one of the following four kinds of protein components: bovine serum albumin (BSA), bovine plasma (BPL), fetal calf serum (FCS) and bovine follicular fluid (BFF). In BSA- and BPL-supplemented media with 0 or 25 ng/ml FSH, more than 50% of follicles showed no degenerative signs during culture, and oocytes significantly increased in size after 4 weeks (P<0.05). Higher percentages of granulosa cell-enclosed oocytes were recovered from the follicles cultured in BPL-supplemented media with 0 and 25 ng/ml FSH, and the oocytes grew to 90 μm or more in diameter. In FCS- and BFF-supplemented media, FSH increased the numbers of degenerating follicles. Next, vitrified-warmed secondary follicles were cultured in BPL-supplemented medium. One third of the follicles showed no degenerative signs, and the oocytes increased in diameter to 88.8 ± 3.1 μm after 4 weeks of culture. These results suggest that a BPL-supplemented medium supports oocyte growth in bovine secondary follicles for 4 weeks, even after vitrification and warming of the follicles.  相似文献