• Microbiology and Biotechnology Letters
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• v.14 no.6
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• pp.495-500
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• 1986

Enzymatic micro-assay methods were studied those were capable of determining ammonia down to 10$^{-5}$M(0.01 $\mu$mole/ml) in the presence of other nitrogenous compounds such as protein and amino acid. Microquantities of ammonia (0.01-0.1 $\mu$mole) could be determined indirectly by measuring phosphorous, one of the products of the enzymatic reaction catalyzed by glutamine synthetase. In this reaction, L-glutamate, ATP and ammonium chloride were used as substrates, and phosphorous was formed in propotion to the concentration of ammonium chloride In the reaction mixture. Another procedure was examined in which glutamine synthetase reaction coupled with pyruvate kinase and lactate dehydrogenase reactions was used. One mililiter of the assay mixture contained; phosphoenol pyruvate, 3 mM, L-glutamate, 10 mM; ATP, 1mM: MgSO$_4$, 20 mM: KCl, 75mM: NADH, 0.2mM: Tris-HCl buffer(pH 7.0), 100mM; pyruvate kinase, 10 U: lactate dehydrogenase, 12 U and glutamine synthetase, 4 U. After preincubation for 20 min at 3$0^{\circ}C$, NH$_4$Cl was added and the rates of NADH oxidation were followed at 340nm. The effective range of this method was proved to be from 0.01 to 0.05 $\mu$mole/$m{\ell}$. Glutamine synthetase reaction coupled with glutamate synthase reaction could also be effectively used for determining microquantities of ammonia. The one mililiter assay mixture contained; ATP, 5mM: L-glutamate, 5mM; L-ketoglutarate, 5mM; MgCl$_2$, 15mM; NADPH, 0.15mM; Tris-HCl buffer(pH 7.0); 100mM; glutamine synthetase, 1U and glutamate synthase, 0.5U. After preincubation for 20min at 3$0^{\circ}C$ NH$_4$Cl was added and the rates of NADPH oxidation were followed at 340nm. The effective range of this procedure was appeared to be from 0.01 to 0.05$\mu$mole/$m{\ell}$.

• Journal of Fisheries and Marine Sciences Education
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• v.12 no.2
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• pp.213-223
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• 2000

In order to establish the exact determination method of amino nitrogen in fish sauces, we compared the amino-nitrogen content in salt-fermented sand lance sauces according to the measuring methods and investigated influencing factors on the procedure of measuring. Amino-nitrogen content was increased in both sand lance sauce during fermentation periods and commercial sand lance sauces. Amino-nitrogen in fermented sand lance sauces for 12 months occupied 88.7% and 75.2% for the trinitrobenzene sulfonic acid(TNBS) method and the Copper-salt method, compare to the Formol method. The ratio of amino-nitrogen/total nitrogen in fermented sand lance sauce for 12 months was higher than in commercial sand lance sauces. The determination of amino-nitrogen by the TNBS method was influenced by concentration of salt in sand lance sauce. The amino-nitrogen content was the highest in the Formol method and followed by the TNBS method and the Copper-salt method without the influence of heating time and monosodium glutamate(MSG) concentration. We concluded that the determination of amino nitrogen in fish sauces was correct to measure with the TNBS method.

• Toxicological Research
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• v.27 no.3
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• pp.143-147
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• 2011

Cadmium is considered one of the most toxic, non biodegradable heavy metal for the human and animals. The purpose of the present study was to investigate the changes in biochemical parameters of blood and accumulation of cadmium in various tissue caused by various levels of dietary cadmium chloride ($CdCl_2$) in broiler chicks. $CdCl_2$ was administered through drinking water to broiler chicks. In spectral analysis, $CdCl_2$ treatment caused a significant increase in Glutamate pyruvate transaminase (GPT), creatinine and uric acid levels in all treated groups. Intriguingly, the GPT, creatinine, and uric acid levels were significantly higher at 75 mg/kg as compared to the groups treated with high doses (100, 125 and 150 mg/kg) of $CdCl_2$. Atomic Absorption Spectrophotometer (AAS) was used for the determination of Cd accumulation in kidney, liver and Breast muscles. AAS analysis revealed that Cd accumulation is increased in breast muscles as compared to liver and kidney at higher doses of Cd than 75 mg/kg.

• Bulletin of the Korean Chemical Society
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• v.25 no.10
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• pp.1499-1502
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• 2004

An amperometric biosensor based on carbon paste electrodes (CPEs) for the determination of urea was constructed by enzyme (urease/GL-DH)-modified method. Urea was hydrolyzed to ${NH_4}^+$ by catalyzing urease onto the enzyme-modified electrode surface in sample solution. In the presence of ${\alpha}$-ketoglutarate and reduced nicotinamide adenine dinucleotide(NADH), a liberated ${NH_4}^+$ produce to L-glutamate and $NAD^+$ by Lglutamate dehydrogenase (GL-DH). After the chemical reaction was proceeded, the electrochemical reaction was occurred that an excess of the NADH was oxidized to $NAD^+$. The oxidation current of NADH was monitored at +1.10 volt vs. Ag/AgCl. An optimum conditions of biosensor were investigated: The optimum pH range for catalyzed hydrolysis reaction of urea was pH 7.0-7.4. The linear response range and detection limit were $2.0\;{\times}\;10^{-5}{\sim}2.0\;{\times}\;10^{-4}M\;and\;5.0\;{\times}\;10^{-6}M$, respectively. Another physiological species did not interfere, except L-ascorbic acid.

• Mass Spectrometry Letters
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• v.14 no.3
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• pp.91-103
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• 2023

As one of the most common mood disorders, numerous studies have shown depression is the main risk factor for non-suicidal self-harm. The pathogenesis of depression is complex, and a comprehensive and rapid measurement of monoamine neurotransmitters and their metabolites will be very helpful in understanding the pathogenesis of depression. Therefore, a rapid and sensitive underivatized liquid chromatography-tandem mass spectrometry method was developed and validated for the simultaneous monitoring of the levels of ten neurotransmitters and their metabolites in rat serum and limbic system and successfully applied to quantify the changes of neurotransmitter levels in chronic unpredictable mild stress-induced rats. The analytes studied were mainly involved in tyrosine metabolism, tryptophan metabolism, and glutamate cycling pathways, which are important in the pathogenesis of depression. It had been verified the method was sensitive and effective, with satisfactory linearity, and met the requirements of biological sample determination. Levels of neurotransmitters in rat serum, hippocampus, amygdala, prefrontal cortex, striatum, and hypothalamus were determined via the method. The results showed serotonin, dopamine, norepinephrine, and their metabolites were decreased, glutamine was increased, and glutamate was disturbed in chronic unpredictable mild stress-induced depression rats. This method provides a new approach to studying the pathogenesis of depression and other neurological disorders.

• Journal of Aquaculture
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• v.16 no.4
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• pp.267-272
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• 2003

This study investigated sex determination through serum steroid hormone level and compared hematological characteristics of one-year old cultured eels, Anguilla japonica. Four different groups were divided with total length at 40∼45, 45∼50, 50∼55, and 55∼60 cm. Males dominated eels of 40∼50 cm in total length group, while females dominated eels of more than 50 cm. All females and males were immature. Hematocrit levels of males (total length: 40∼50 cm) were higher than those of females (total length: 50∼60 cm). Hemoglobin content also differed between males and females. Glutamate oxaloacetate transaminase (GOT) levels of 40∼45 cm males tended to be higher (157$\pm$3.46 IU/L) than that of other sized males, but there were no significant differences between groups (P<0.05). The highest GOT levels were found in of 55∼60 cm females (148$\pm$3.46 IU/L) compared with that of other female groups (P<0.05). Glutamate pyruvate transaminase (GPT) levels of males and females in the 55∼60 cm size range was significantly higher thanothers (P<0.05). The result of this study indicated steroid hormone content of males and females were very low, but testosterone (T) and estradiol-17$\beta$, (E2) contents of females were higher than those of males. For further research of sex determination in cultured eels, it needs to investigate in more defined body length.

• Applied Biological Chemistry
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• v.20 no.2
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• pp.205-209
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• 1977

The pool size of plasma glucose, turnover rate and other concerned items for glucose metabolism in normal laying hen were investigated by a single-injection method using $U-C^{14}-glucose$. The 11.6 nCi of pure dose was injected to a hen normally fed through the wing vein. The glucose concentration in plasma sample taken at 5 minutes after injections was 214mgper 100ml. From the plottings of logarithmic standard specific activities of plasma taken from 5 to 120 minutes against the time after injection and from the regresion analysis, metabolic states were determined. The pool size was 1.07g, turnover rate was 0.024 per minute, turnover time was 41 minutes, utilization rate was 26mg/min. (0.83 g/hr/kg B.W. 3/4) and glucose space(extracellular fluid volume) was 25.3 per cent of body weight. The values obtained from. 10-50 minutes samples were similar to those described above, which we from 5-120 minutes samples.

• Journal of Microbiology and Biotechnology
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• v.28 no.5
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• pp.718-731
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• 2018

The beneficial effects of lactic acid bacteria (LAB) have been intensively investigated in recent decades with special focus on modulation of the host intestinal microbiota. Numerous discoveries of effective probiotics are driven by a significantly increasing demand for dietary supplements. Consequently, technological advances in the large-scale production and lyophilization are needed by probiotic-related industries for producing probiotic LAB for commercial use. Our study had a dual objective, to determine the optimum growth medium composition and to investigate appropriate cryoprotective additives (CPAs) for Lactobacillus salivarius, and compare its responses with other Lactobacillus species. The one-factor-at-a-time method and central composite design were applied to determine the optimal medium composition for L. salivarius cultivation. The following composition of the medium was established (per liter): 21.64 g maltose, 85 g yeast extract, 1.21 ml Tween 80, 6 g sodium acetate, $0.2g\;MgSO_4{\cdot}7H_2O$, $0.02g\;MnSO_4{\cdot}H_2O$, $1g\;K_2HPO_4$, $1.5g\;KH_2PO_4$, $0.01g\;FeSO_4{\cdot}7H_2O$, and 1 g sodium citrate. A cryoprotective additive combination comprising 10% (w/v) skim milk and 10% (w/v) sucrose supplemented with 2.5% (w/v) sodium glutamate was selected for L. salivarius, and its effectiveness was confirmed using culture-independent methods in the freeze-dried cells of the Lactobacillus strains. In conclusion, the optimized medium enhanced the species-specific cultivation of L. salivarius. On the other hand, the cryoprotective effects of the selected CPA mixture may also be dependent on the bacterial strain. This study highlights the necessity for precise and advanced processing techniques for large-scale production of probiotics in the food and feed industries.