Koichi Zama

Deterioration of chum salmon (Oncorhynchus keta) muscle during spawning migration—I. Changes in proximate composition of chum salmon muscle during spawning migration

Abstract 1. 1. The chemical compositions of chum salmon muscle during spawning migration were compared in terms of their physiological conditions. 2. 2. The gonadosomatic index (GSI) values were significantly elevated during the spawning migration stage, and high values were maintained during the upstream migration. The changes in GSI values were related to the hormone levels of testosterone and estradiol-17β. 3. 3. Muscle lipid content significantly decreased during the spawning migration stage, while a decrease in muscle protein was found during the upstream migration stage. Phospholipid content was constant during spawning migration. 4. 4. It was considered that lipid (triglyceride) and protein were utilized to mature the gonads and as an energy source to ascend the river, respectively.

A new concept for determining triglyceride composition of fats and oils by liquid chromatography

The matrix concept was used to characterize the chromatographic rules in the elution of molecular species of triglyceride. To prove the hypothesis experimentally, cacao butter, palm oil, linseed oil, olive oil, rapeseed oil and triglyceride of “Ogonori” (Gracilaria verrucosa) were examined. A matrix model was suggested to help determine the individual molecular species of naturally occurring triglycerides.

Deterioration of chum salmon (Oncorhynchus keta) muscle during spawning migration—III. Changes in protein composition and protease activity of juvenile chum salmon muscle upon treatment with sex steroids

Abstract 1. 1. Changes in protein composition and protease activity of juvenile chum salmon muscle upon treatment with sex steroids were investigated. 2. 2. A slight breeding color was observed on chum salmon following the oral administration of 17α-methyltestosterone. Sarcoplasmic protein significantly decreased, while ninhydrin-positive substances from protein-free fractions significantly increased upon treatment with 17α-methyltestosterone. Autolytic activity of the fish treated with 17α-methyltestosterone drastically increased. 3. 3. Estradiol-17β did not significantly influence the protein composition and autolytic activity. 4. 4. These results indicate that androgen is closely related to the deterioration of chum salmon muscle.

A mathematical model for the prediction of triglyceride molecular species by high performance liquid chromatography

The physicochemical and theoretical relationships between the traditional equivalent carbon number (ECN) and a proposed elution theory for triglyceride molecular species that has been expressed as a matrix model were demonstrated by multiple regression analysis. It was concluded that the ECN expression has two independent variables, that is, the total acyl carbon number (CN) and the total double bonds (DB), and one dependent variable, the relative retention time (RRT). In the proposed elution equation, there are six independent variables, including the carbon numbers and number of double bonds in each acyl group to be considered.

Supplementary consideration of the triglyceride matrix model on reverse phase high performance liquid chromatography

The matrix model that has been expressed as linear relationship between the logarithm of the relative retention time of a molecular species of a triglyceride versus total acyl carbon number or total double bonds when only one acyl group differs in carbon number or number of double bonds was reviewed. A similar linear relationship was observed when the fatty acid residues were substituted in the triglyceride molecule. This relationship was demonstrated by introducing the theory of partition chromatography presented by A.J.P. Martin.

Discernment of relative retention values of triglyceride α,β isomers on reverse phase high performance liquid chromatography

Discernment of α,β isomers of triglyceride on reverse phase high performance liquid chromatography (HPLC) was investigated by the use of a multiple regression analysis. The retention effect of triglyceride molecular species was considered to be dependent principally on the addition theorem of chemical potential of both position α and position β (acyl carbon numbers and numbers of double bonds in the acyl group), though it was observed that the retention effect of position α is somewhat larger than that of position β on HPLC when it has the same acyl group combination.

Interactions between lipid and protein. Effect of gel fraction on carp myosin B ATPase activity.

The effect of gel fraction on carp myosin B ATPase activity was investigated in connection with interactions between lipid and protein. Ca2+-ATPase and Mg2+-ATPase activities of myosin B at low and high ionic strength increased and decreased, respectively, by the removal of the gel fraction. Ca2+-ATPase and Mg2+-ATPase activities of the gel fraction treated with Triton X-100 were higher and lower, respectively, than those of the untreated gel fraction. These results showed that Mg2+-ATPase of myosin B was accelerated, while Ca2+-ATPase of myosin B was inhibited, by the lipids contained in the gel fraction. It was also shown that there were no membrane and mitochondrial ATPases because neither azide nor ouabain depressed the cativity. The major lipids of myosin B, and the gel fraction were composed of lecithin, cephalin, and triglyceride. The relative amounts of phospholipids in the total lipids obtained from the gel fraction were larger than those obtained from other fractions. Since phospholipids were composed mainly of unstaturated fatty acids, the degrees of unsaturation in fatty acid compositions might be connected with myosin B ATPase activity.