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Volume 28 (1987)
- Issue 6 Pages 427-
- Issue 5 Pages 311-
- Issue 4 Pages 219-
- Issue 3 Pages 159-
- Issue 2 Pages 109-
- Issue 1 Pages 1-
Volume 28, Issue 3
Displaying 1-8 of 8 articles from this issue
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Hirotaka OBANA, Sei-ichi NAKAMURA1987 Volume 28 Issue 3 Pages 159-163_1
Published: June 05, 1987
Released on J-STAGE: December 11, 2009
JOURNAL FREE ACCESSIn order to detect anti-mutagens, foods investigated in the total diet study were surveyed with the umu test, which is a new system to detect environmental mutagens. Its principle is to detect the induction of SOS responses which are involved in the formation of mutation. SOS responses were induced with various mutagens, and the suppressive effect of food was studied.
Vegetables and fruits showed suppression when SOS responses were induced by activated Trp-P-1. These foods did not show suppression when SOS responses were induced by UV irradiation, suggesting that inactivation of Trp-P-1 may cause the suppression. Coffee suppressed the induction of SOS responses not only by activated Trp-P-1 but also by UV or AF-2. The suppressive effect of coffee seems to be due to an effect other than the inactivation of mutagens.View full abstractDownload PDF (726K) -
Kenji CHIMI, Shin-ichiro KATSUDA, Noriji TABA, Isao NIIYA1987 Volume 28 Issue 3 Pages 164-168_1
Published: June 05, 1987
Released on J-STAGE: December 11, 2009
JOURNAL FREE ACCESSThe effects of gonyautoxins (GTXs) on neuromuscular transmission and impulse conduction in the nerve were studied in the sciatic-nerve sartorius-muscle preparation of a frog. The preparation was placed in an experimental chamber and immersed in Ringer's solution. End plate potential (EPP) was recorded through a glass micropipette advanced into the muscle fiber near the motor nerve terminal. Action potential (AP) of the motor nerve was monitored simultaneously with EPP through a micropipette kept in contact with the motor nerve on the surface of the muscle. EPP suddenly disappeared about 3min after exposure of the preparation to Ringer's solution containing GTXs (0.1MU/ml) and abruptly recovered in amplitude and waveform to the control level 5min after wash-out of the toxins from the preparation. AP was completely abolished by the application of GTXs and this effect was also reversed by the removal of the toxins. However, prolongation of latency was observed in the restored EPP and AP. These results suggest that GTXs might suppress impulse conduction along the motor nerve and inhibit EPP.View full abstractDownload PDF (527K) -
Teizo SUGIMOTO, Koichi YAMAMOTO, Masatoshi MINAMISAWA1987 Volume 28 Issue 3 Pages 169-174_1
Published: June 05, 1987
Released on J-STAGE: December 11, 2009
JOURNAL FREE ACCESSWe have developed an analytical method for rapidly determining deoxynivalenol (DON) and nivalenol (NIV), typical mycotoxins in cereals infected by Fusarium spp., in wheat and barley. Since we used a solvent of high polarity and water to elute columns of mixed alumina-charcoal-celite and Amberlite for extraction and clean-up, we were able to omit partition and dehydration processes. The separated mycotoxin was determined by ECD-gas chromatography after trimethylsilylation. The limits of determination of DON and NIV are 12ng/g, and that of fusarenon-X (F-X) is 24ng/g. These limits are adequate for economic screening analysis. When DON and NIV were added to wheat and barley at the 120ng/g level and F-X at the 240ng/g level, the recoveries were 101 and 95%, 93 and 92%, and 96 and 96%, and the coefficients of variation were 2.9 and 3.4%, 3.7 and 2.4%, and 3.5 and 3.4%, respectively. When F-X was detected by this method, its identity was confirmed by mass chromatography. So far we have not detected F-X in cereals. Further studies are in progress. This method was designed for rapid determination of wheat and barley, but should also be applicable to the analysis of mixed feed. It is easy to change the limits of determination by changing the quantities of sample and solvent. One analyst can analyze 8 samples in a day, and two analysts, 20 samples.View full abstractDownload PDF (656K) -
Takahisa KAMIYA, Kahoru KUBOTA, Kazunori YAMAMOTO, Michihiko KOMURO, S ...1987 Volume 28 Issue 3 Pages 175-179_1
Published: June 05, 1987
Released on J-STAGE: December 11, 2009
JOURNAL FREE ACCESSFifty chickens prepared for sale and 15 samples each of minced and non-minced chicken for use as raw material for processed food were collected and strains of Clostridium perfringens were isolated from them. The number of isolates was 153 and the isolation frequencies of the organism from these 3 kinds of samples were 34%, 100%, and 87%, respectively. Among these 153 isolates, there were 32 strains that were extraordinarily resistant to heat; 30 of the 32 strains were resistant to 100°C for 10 minutes, and the other 2, to 100°C for 60 minutes. However, no enterotoxigenicity was found with these 32 strains, though 1 strain was found to be enterotoxigenic by reversed passive hemagglutination tests.
The MICs of tetracycline for 114 selected strains were examined by the plate dilution method. Strains resistant to 12.5μg/ml of tetracycline amounted to 84 of the 114 strains, and 53 of these 84 strains were found to be highly resistant to the drug with MICs of more than 25μg/ml. Tetracycline resistance-transfer experiments were carried out using 53 highly resistant strains as donors and 2 recipient strains which are maintained in our laboratory. Transferable tetracycline R-plasmids were detected in 41 of the 53 highly resistant strains.
Tetracycline R-plasmids were extracted from these transcipients and treated with the restriction endonuclease, EcoRI. Several different restriction profiles were observed among the plasmids.View full abstractDownload PDF (2204K) -
Rapid Determination of Trace Metals in Cow's Milk by Graphite Furnace Atomic Absorption SpectrometryNaoko OIKAWA, Kumiko TAGUCHI, Naomi SUZUKI, Kohei KOJIMA1987 Volume 28 Issue 3 Pages 180-189_1
Published: June 05, 1987
Released on J-STAGE: December 11, 2009
JOURNAL FREE ACCESSA rapid procedure of determination, without digestion, for trace metals in cow's milk was devised by the use of a polarized Zeeman atomic absorption spectrophotometer and graphite atomizers. The simplified standard addition method was employed using the sample diluted with 70v/v% ethanol so as to prevent bumping during drying in the atomizer. Then, in order to promote the decomposition of organic matter and to unify the chemical form and valence of the metal, as well as of coexisting components, nitric acid was added to the standard metal solution to be added to the sample solution dried in the atomizer. In the determination attempted for copper, zinc, iron, lead and cadmium in milk, satisfactory results were obtained. Furthermore, this method was confirmed to be useful by comparing the result with those of other methods, such as the standard addition method and the wet digestion-solvent extraction method. The peak area mode was used for calculation. For the determination of cadmium, dilution of milk was necessary and wavelengths other than their primary resonance lines had to be used for the determination of zinc and iron.View full abstractDownload PDF (1192K) -
Yasutaka KATSUKI, Shigeru MATSUMOTO, Hideo TSUYUKI1987 Volume 28 Issue 3 Pages 190-195_1
Published: June 05, 1987
Released on J-STAGE: December 11, 2009
JOURNAL FREE ACCESSTo examine the autoxidation of unsaturated triglycerides obtained from glycerol and oleic acid and the antioxidative effect of α-tocopherol (α-Toc) or synergism of ascorbic acid (AA), experiments were carried out on purified triolein (TO), by introducing oxygen at 75°C into an apparatus similar to that employed previously. Methyl oleate (MO) prepared from the same source was used for comparison. Samples were taken at various oxidation times, and several chemical constants such as peroxide value (POV), dinitrophenylhydrazine value, thiobarbituric acid value (TBAV), acid value, etc. were measured. The IR absorption spectra were also examined. Further, the effects of α-Toc and AA were studied.
The results obtained were as follows. The reproducibility of oxidation using a small volume of sample was good under the conditions studied. The induction period for POV to reach 500meq/kg was much shorter with TO than MO, and the TBAV of TO was found to be half that of MO. The other chemical constants of TO resembled those of MO after the induction period. The antioxidative effect of α-Toc and the synergistic effect of AA were clearly seen with both TO and MO; the synergistic effect of AA was greater with TO than with MO.View full abstractDownload PDF (695K) -
Sumiko TSUJI, Akihiro TSUMURA, Yumiko NAKAMURA, Yasuhide TONOGAI, Yosh ...1987 Volume 28 Issue 3 Pages 196-199_1
Published: June 05, 1987
Released on J-STAGE: December 11, 2009
JOURNAL FREE ACCESSIn the determination of hydrogen peroxide in foods containing catalase by the oxygen electrode method, a part of the hydrogen peroxide is decomposed enzymatically. Therefore, the sample was treated with metaphosphoric acid to inactivate catalase and hydrogen peroxide was determined by the oxygen electrode method. With this metaphosphoric acid method, more than 70% of spiked hydrogen peroxide was recovered from chicken liver at the 50μg/g level, from semi-dried sardine at the 5μg/g level and from shirasuboshi at the 1μg/g level.
Hydrogen peroxide contents in the various foods were determined and compared by the oxygen electrode method with and without metaphosphoric acid pretreatment (original method and metaphosphoric acid method). Hydrogen peroxide in food containing low catalase activity (not more than 4U/g) gave almost the same value in both methods. Hydrogen peroxide in food containing high catalase activity (more than 20U/g) could not be detected by the original method, but could be detected by the metaphosphoric acid method.
It is recommended that hydrogen peroxide in food containing high catalase activity should be determined by using the metaphosphoric acid method.View full abstractDownload PDF (547K) -
Hirofumi USHIYAMA, Motohiro NISHIJIMA, Kazuo YASUDA, Hisashi KAMIMURA, ...1987 Volume 28 Issue 3 Pages 200-204_1
Published: June 05, 1987
Released on J-STAGE: December 11, 2009
JOURNAL FREE ACCESSAn analytical method was developed for the determination of isopropyl citrate in edible oil.
The sample was dissolved in ethyl acetate and mono- and diisopropyl citrate were extracted with 5% sodium bicarbonate. The aqueous layer was acidified with phosphoric acid and isopropyl citrates were extracted with ethyl acetate. The ethyl acetate layer was dried with anhydrous sodium sulfate and evaporated to dryness. The residue was fluorescence-labeled with 4-bromomethyl-7-methoxycoumarin (Br-Mmc). Thin layer chromatography was used for the qualitative determination of fluorescence-labeled mono- and diisopropyl citrates.
Qualitative determination was carried out as follows. The sample was hydrolyzed with potassium hydroxide solution. The hydrolyzed solution was washed with hexane and applied to the Amberlite IRA-402 column. Citric acid was eluted with 1N hydrochloric acid. The eluate was evaporated to dryness, and the residue was dissolved in water. High performance liquid chromatography was used for quantitative determination of citric acid.
The recoveries of isopropyl citrates added to edible oil were in the range from 84% to 93% and the detection limit of monoisopropyl citrate was 5μg/g.View full abstractDownload PDF (530K)
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