Chiaki Shimizu

High-performance liquid chromatography of 5,8,11,14,17-Eicosapentaenoic acid in fatty acids (C18 and C20) by labelling with 9-anthryldiazomethane as a fluorescent agent

Abstract A sensitive high-performance liquid chromatographic method using 9-anthryldiazomethane has been developed for the separation and determination of 5,8,11,14,17-eicosapentaenoic acid (EPA) from C18 and C20 fatty acids, with a view to its application to the HPLC determination of EPA in fish and human blood or serum and in plankton body fluid. The limit of detection of EPA is about 300 pg and the coefficient of variation is 2.1%.

Feeding stimulation in sea bream, Pagrus major, fed diets supplemented with Antarctic krill meals

Abstract Feeding behavior is stimulated when fish are fed diets supplemented with Antarctic krill, Euphausia superba, meal. An electrophysiological method was used to study the olfactory and gustatory responses of sea bream, Pagrus major, to extracts of krill meal, non-muscle krill meal, and white fish meal. It was observed that the non-muscle krill meal elicited the strongest responses; non-muscle krill meal gave about 1.5 times and krill meal 1.2 times the response of the white fish meal. Amino acid analysis of the meals indicated that non-muscle krill meal was high in sarcosine, proline, glutamic acid, arginine and glucosamine. These amino acids are believed to be the cause of the gustatory and olfactory responses observed. Several diets containing these amino acids were tested for feeding stimulation in sea bream. It was shown that sea bream feeding was stimulated mainly by proline, glycine and glucosamine.

Pigmentation of cultured red sea bream, Chrysophrys major, using astaxanthin from Antarctic krill, Euphausia superba, and a mysid, Neomysis sp.

Abstract Pigmentation enhancement in cultured red sea bream, Chrysophrys major , was investigated using Antarctic krill, Euphausia superba , and a mysid, Neomysis sp., as a source of astaxanthin. Diets fortified with processed Antarctic krill (krill meal) and its acetone extract, containing 0.82–4.92 mg carotenoids/100 g dry weight, and raw krill and raw mysid supplemented diets, containing about 2.00 mg carotenoids/100 g wet weight, were formulated and tested for carotenoid deposition. The rate of carotenoid deposition in fish fed with raw krill and raw mysid was significantly higher and resulted in distinct pigmentation. The groups fed with the krill meal and acetone extract diets showed varied concentrations of skin carotenoids and resulted in faint pigmentation. Pigmented fish then fed on a carotenoid-free diet for the same length of time showed no apparent differences in the skin pigmentation although the detectable amounts of carotenoids varied. The bream converted some of the dietary astaxanthin to skin tunaxanthin.

Kinetics of a Chitinase from a Prawn, Penaeus japonicus

Kinetic analysis was done on a chitinase (EC 3.2.1.14) purified from the liver of a prawn, Penaeus japonicus, using N-acetylchitooligosaccharides (GlcNAcn, n = 2 to 6), p-nitrophenyl N-acetylchitooligosaccharides (pNp-GlcNAcn, n = 1 to 5), and colloidal chitin as the substrates. The enzyme hydrolyzed GlcNAc4 to two molecules of GlcNAc2, GlcNAc5 to GlcNAc2 plus GlcNAc3, and GlcNAc6 by two ways to GlcNAc2 plus GlcNAc4 (87%), and two molecules of GlcNAc3 (13%). Neither GlcNAc2 nor GlcNAc3 was hydrolyzed. The Km and kcat were 0.249 mm and 3.38 sec−1 for GlcNAc4,0.018 mm and 2.67 sec−1 for GlcNAc5, and 0.005 mm and 2.72 sec−1 for GlcNAc6, respectively. The cleavage patterns of p-nitrophenyl N-acetylchitooligosaccharides were different from those of the corresponding N-acetylchitooligosaccharides. The enzyme hydrolyzed colloidal chitin to produce mainly GlcNAc2 and a trace of GlcNAc3. Allosamidin inhibited prawn chitinase in a competitive way with a Ki of 0.1 μm and IC50 of 0.14 μm. These results suggest that p...

Gas chromatographic determination of hydrogen sulphide in anoxic waters

Abstract A gas chromatographic method has been studied for the determination of hydrogen sulphide in anoxic waters. To suppress the escape and the oxidation of hydrogen sulphide in the water sample, either acetone or ethanol was mixed with the sample, and a small amount of hydroxylamine hydrochloride was added. The hydrogen sulphide in this solution was determined by gas chromatography. The proposed method is easy to perform and determination is possible for several days after the sampling. The limit of detection was about 0.1 ppm, the average of coefficients of detection was 9.2%.

Occurrence of bilirubin-IXβ in the gallbladder bile of eel, Anguilla japonica

Abstract Bilirubin-IXβ isomer was detected in the bile of eel, Anguilla japonica, as evidence by high-performance liquid chromatography (HPLC) analysis of free acid and its ethyl anthranilate diazo derivatives. Bilirubin-IXβ accounted for 16.7 ± 6.0 (mean ± S.D.) percent of the total bilirubins in the bile of 40 eels analysed, and the percentage was much higher than that reported in the biles of mammals.

A problem in the spectrophotometric determination of dissolved total phosphorus in brackish anoxic waters

Abstract When dissolved total phosphorus in anoxic brackish waters was determined spectrophotometrically by the heteropoly molybdenum blue method after oxidation with potassium peroxodisulfate, negative dissolved organic phosphorus contents were obtained from the differences between the total phosphorus and inorganic phosphorus contents. A major cause of this inconsistency is coprecipitation of phosphate with the colloidal hydrated iron(III) oxide produced fro miron in these waters, or the formation of iron(III) phosphate during the oxidation process. The problem can be avoided by oxidation with nitric and perchloric acids.

A high-speed liquid chromatography of phosphorus in anoxic waters occurring in a bay using solvent extraction of molybdoheteropoly yellow

ZusammenfassungDas beschriebene Verfahren zur Phosphorbestimmung in anoxischen Wässern beruht auf der Extraktion von Molybdoheteropolygelb mit Methylpropionat und anschließender HPLC. Störendes Silicium wird durch diese Extraktion eliminiert und Phosphor kann im Bereich von 0,015 bis 0,2 ppm schnell und genau bestimmt werden (Variationskoeffizient 4,4%).SummaryA new method for the determination of phosphorus in anoxic waters by high-speed liquid chromatography was developed. It is based on the extraction of molybdoheteropoly yellow with methyl propionate. The interference of co-existing soluble silica is effectively eliminated by this extraction, and micro-amounts of phosphorus ranging from 0.015 to 0.2 ppm in the anoxic waters can be determined rapidly and exactly (coefficient of variation 4.4%).