Analysis of acrylamide in a complex matrix of polyacrylamide solutions treated by heat and ultraviolet light     

Ishizuka M  Fujioka K  Shibamoto T 《Journal of agricultural and food chemistry》2008,56(15):6093-6096

A recently developed headspace/solid-phase microextraction/gas chromatograph (GC) equipped with a nitrogen-phosphorus detector (NPD) (HS/SPME/GC/NPD) method was used to analyze acrylamide formed in an aqueous polyacrylamide solution (25%) treated by heat or photo-irradiation. Original polyacrylamide contained 0.43 +/- 0.11 microg/mL of acrylamide. When polyacrylamide solution was heated at 70 degrees C for 16 h with 0.5% potassium persulfate, the amount of acrylamide increased to 1.02 +/- 0.11 microg/mL. When polyacrylamide solution was irradiated by UV (lambda = 300 nm) for 16 h with 0.05% 2-anthraquinone sulfate sodium salt, the amount of acrylamide increased to 1.14 +/- 0.54 microg/mL. Polyacrylamide has been used in cosmetic formulations. The present study, therefore, suggests that there is another route of acrylamide exposure to humans in addition to foods and beverages.  相似文献   

Partial purification from hot dogs of N-nitroso compound precursors and their mutagenicity after nitrosation     

Zhou L  Haorah J  Perini F  Carmella SG  Shibamoto T  Mirvish SS 《Journal of agricultural and food chemistry》2006,54(15):5679-5687

Hot dogs contain apparent N-nitroso compounds (ANC) and ANC precursors (ANCP). ANCP purification was followed by nitrosation, sulfamic acid treatment, and analysis for ANC. Aqueous hot dog extracts were adsorbed on silica gel, which was eluted with MeCN and MeOH. The MeOH eluate was adsorbed on cation exchange resin (H+ form) and eluted with NH4OH. Eluted ANCP traveled at moderate speeds in high-performance liquid chromatography (HPLC) on amino and Pb2+ columns. Gas chromatography-mass spectrometry (GC-MS) of trimethylsilyl (TMS) derivatives of crude water extract indicated the presence of glycerol, phosphate, lactic acid, and two monosaccharides. GC-MS of TMS derivatives of Pb2+ column HPLC eluates indicated that ANCP included 1-deoxy-N-1-glucosyl glycine. The nitrosated NH4OH eluate showed 4x background mutagenic activity for Salmonella typhimurium TA-100. Un-nitrosated fractions showed 2x background activity. Although tryptophan nitrosation gave 88% ANC yield, tryptophan is probably not a major ANCP in hot dogs. Hot dog patties prepared with or without sucrose or glucose showed similar ANC and ANCP levels. We discuss possible implications of these findings for the etiology of colon cancer.  相似文献   

Isolated chloroplast division machinery can actively constrict after stretching     

Yoshida Y  Kuroiwa H  Misumi O  Nishida K  Yagisawa F  Fujiwara T  Nanamiya H  Kawamura F  Kuroiwa T 《Science (New York, N.Y.)》2006,313(5792):1435-1438

Chloroplast division involves plastid-dividing, dynamin, and FtsZ (PDF) rings. We isolated intact supertwisted (or spiral) and circular PDF machineries from chloroplasts of the red alga Cyanidioschyzon merolae. After individual intact PDF machineries were stretched to four times their original lengths with optical tweezers, they spontaneously returned to their original sizes. Dynamin-released PDF machineries did not retain the spiral structure and could not be stretched. Thus, dynamin may generate the motive force for contraction by filament sliding in dividing chloroplasts, in addition to pinching-off the membranes.  相似文献   

Factors governing cesium adsorption of charcoals in aqueous solution     

Shigeru Yamauchi  Takayuki Yamagishi  Kazuko Kirikoshi  Mitsuyoshi Yatagai 《Journal of Wood Science》2017,63(2):183-191

Cesium adsorption by commercial charcoals was examined to elucidate the mechanisms for capturing cesium ions in aqueous solution. Changes in the adsorption ability of charcoals due to water extraction (water washing) were investigated to develop practical cesium adsorptives based on charcoal. The commercial charcoals examined included mangrove charcoal (MC) and ubamegashi (Quercus phillyraeoides A. Gray) bincho charcoal (BC). Data from the two charcoals were compared with those of Japanese oak (Quercus serrata Thunb. and/or Quercus crispula Blume) charcoal (OC) reported previously. Aqueous cesium chloride solution (2.50 × 10^?5 mol/L) was used as a sample solution for the adsorption study. Charcoal powder was used as an adsorbent after passing through a 60-mesh sieve. The powders were characterized using methods, such as Raman spectroscopy, X-ray fluorescence spectrometry, and infrared photoacoustic spectroscopy. The results indicated that MC, which was manufactured at the lowest possible temperature and had the smallest specific surface area, possessed the greatest ability to adsorb cesium. The MC also had the great cesium-adsorption ability in weak acidic solution and maintained the ability even after lengthy extraction treatments.  相似文献   

Changes to vertical thermoregulatory movements of juvenile bigeye tuna (Thunnus obesus) in the northwestern Pacific Ocean with time of day,seasonal ocean vertical thermal structure,and body size     

Haruhiko Hino  Takashi Kitagawa  Takayuki Matsumoto  Yoshinori Aoki  Shingo Kimura 《Fisheries Oceanography》2019,28(4):359-371

Vertical movements related to the thermoregulation were investigated in 12 juvenile bigeye tuna (Thunnus obesus) in Japanese waters using archival tag data. Movements changed with time of day, season, and body size. During daytime, bigeye tuna descended to greater depths, presumably to feed in the deep scattering layer (DSL). Thereafter, they repeatedly ascended to shallower layers, suggesting attempts at behavioral thermoregulation, although the beginning of vertical thermoregulatory ascents might reflect a shift in DSL depth. By the end of such movement, the whole‐body heat‐transfer coefficient might decrease because, although the depth and ambient temperature of the upper layers did not change, the body temperature gradually decreased significantly just after ascent for thermoregulation. Seasonal patterns indicated that the vertical thermal structure of the ocean might influence this ascent behavior. For example, from January to May, bigeye tuna made fewer ascents to less shallow waters, suggesting that they respond to increasing depths of the mixed surface layer by reducing energy expenditure during vertical migration. In addition, as body size increased, fewer thermoregulatory ascents were required to maintain body temperature, and fish remained deeper for longer periods. Thus, vertical thermoregulatory movements might change with body size as bigeye tuna develop better endothermic and thermoregulatory abilities. We hypothesize that bigeye might also increase cold tolerance as they grow, possibly due to ontogenetic shifts in cardiac function.  相似文献   

Expression of podoplanin in various types of feline tumor tissues     

Satoshi KAMOTO  Masahiro SHINADA  Daiki KATO  Masaya TSUBOI  Sho YOSHIMOTO  Ryohei YOSHITAKE  Shotaro ETO  Namiko IKEDA  Yosuke TAKAHASHI  Yuko HASHIMOTO  James CHAMBERS  Kazuyuki UCHIDA  Shinji YAMADA  Mika K. KANEKO  Ryohei NISHIMURA  Yukinari KATO  Takayuki NAKAGAWA 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2021,83(11):1795

Podoplanin is expressed in various human tumors where it promotes tumor progression, epithelial-mesenchymal transition, and distant metastasis. Podoplanin is also expressed in cancer-associated fibroblasts and induces tumor malignancy. The objective of this study was to evaluate podoplanin expression in various types of feline tumor tissues. Immunohistochemical analysis revealed that podoplanin was expressed in cells of 13/15 (87%) squamous cell carcinomas and 5/19 (26%) fibrosarcomas. Moreover, cancer-associated fibroblasts expressed podoplanin in most tumor types, including 18/21 (86%) mammary adenocarcinoma tissues. Our findings demonstrate that various types of feline tumor tissues expressed podoplanin, indicating the importance of the comparative aspects of podoplanin expression, which may be used as a novel research model for podoplanin biology.  相似文献   

Amphidiploids between Alstroemeria ligtu L. hybrid and A. pelegrina L. var. rosea induced through colchicine treatment and their reproductive characteristics     

Takayuki Ishikawa  Tomoko Takayama  Hiroshi Ishizaka 《Scientia Horticulturae》1999,80(3-4):235-246

Interspecific hybrids of Alstroemeria ligtu L. hybrid (LH) (2n = 16) and A. pelegrina L. var. rosea (PR) (2n = 16) synthesized by cross-breeding, exhibited a low pollen fertility and failed to produce normal seeds by self-pollination. To produce amphidiploids of LH × PR the ovules of LH × PR were treated with 0.05% aqueous colchicine for 2, 4 or 8 days or the rhizomes of the mature LH × PR were treated with 0.5% aqueous colchicine for 1, 2, 4 or 7 days. A total of 6 mature plants were obtained from the ovules of LH × PR treated with colchicine. Among them 2 plants derived from the ovules treated with colchicine for 4 days were found to be amphidiploids (2n = 32). A total of 17 rhizomes treated with colchicine, sprouted. Among them, 1 and 3 plants developed from the rhizomes treated with colchicine, for 1 and 4 days, respectively, were fertile. The plants developed from seeds obtained by self-pollination were amphidiploids with a chromosome number of 2n = 32. Although each of the amphidiploids induced by colchicine and LH × PR exhibited the characteristics of the parents, the colchicine-induced amphidiploids showed larger flowers than LH × PR and grew more vigorously. Even though the amphidiploids failed to produce normal seeds by self-pollination, pollen fertility was relatively high and their progenies were produced from self-pollinated ovules by ovule culture. The amphidiploids were crossed with LH, PR, A. aurea Graham, A. paupercula Philippi and A. psittacina Lehm., resulting in the production of triploids with a chromosome number of 2n = 24.  相似文献   

Turbulence effect on survival and feeding of pacific bluefin tuna <Emphasis Type="Italic">Thunnus orientalis</Emphasis> larvae,on the basis of a rearing experiment     

Yoshiki Kato  Takayuki Takebe  Shukei Masuma  Takashi Kitagawa  Shingo Kimura 《Fisheries Science》2008,74(1):48-53

ABSTRACT:   Physical conditions such as oceanic turbulence related to food availability are considered to be important factors affecting fish larval survival. Rearing experiments were conducted to elucidate the effects of turbulence on the survival and feeding rates during the initial feeding period of Pacific bluefin tuna Thunnus orientalis . Six levels of turbulence intensity were provided by changing flow rates from pipes set on the bottom of rearing tanks. The result showed a dome-shaped relationship between turbulence level and survival rate, in which the feeding rate appeared higher at a logged turbulence energy dissipation rate of −6.32, and decreased at both higher and lower turbulence levels. Compared with the turbulence intensity in the ocean, the optimal turbulence level for Pacific bluefin tuna larvae corresponded to the turbulence caused by sea surface winds with speeds of 4–12.5 m/s. The estimated optimal turbulence intensity for Pacific bluefin tuna larvae is comparable to that for yellowfin tuna Thunnus albacares .  相似文献   

Effect of combination feeding of <Emphasis Type="Italic">Nannochloropsis</Emphasis> and freshwater <Emphasis Type="Italic">Chlorella</Emphasis> on the fatty acid composition of rotifer <Emphasis Type="Italic">Brachionus plicatilis</Emphasis> in a continuous culture   总被引：1，自引：1，他引：0  

Takayuki Kobayashi  Toshiya Nagase  Akinori Hino  Toshio Takeuchi 《Fisheries Science》2008,74(3):649-656

ABSTRACT:   A continuous culture of rotifer was conducted to investigate the effect of combination feeding of both a high density of Nannochloropsis oculata (N) and condensed freshwater Chlorella (FC) on the fatty acid composition of L-type rotifer Brachionus plicatilis in a continuous culture system. The algal feeding of the rotifers was carried out in three successive steps: N-feeding → N+FC-feeding → FC-feeding. The culture was conducted at 24°C and 25–27 psu in a 2000 mL bottle with 50% of water exchanged daily. The combination N+FC-feeding was effective in increasing rotifer density. The rotifers fed on N+FC (N+FC-R) had more non-polar lipids than polar ones, similar to those on N (N-R), opposite to the rotifers fed on FC (FC-R). N+FC-R contained higher levels of 16:2, 18:2n-6 (linoleic acid [LA]) and 20:2n-6, but lower levels of 18:1, 20:4n-6 (arachidonic acid), 20:5n-3 (eicosapentaenoic acid [EPA]) and 22:5n-3 (docosapentaenoic acid [DPA]) compared with N-R. Whereas N+FC-R contained higher levels of 16:1n-7, EPA and DPA, but lower levels of 16:2 and LA compared with FC-R. N+FC-R had more DPA in polar lipids than in non-polar ones. The Σn-6/Σn-3 ratio in N+FC-R was 0.9–1.0, significantly different from those in N-R (0.4) and FC-R (6.6–8.4). Therefore, it is inferred that the fatty acid profile of the N+FC-R cultured in a continuous culture system was affected by both N and FC. Also, the combination N+FC-feeding may be effective in manipulating the Σn-6/Σn-3 ratio in continuously cultured rotifers.  相似文献