• Journal of Nutrition and Health
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• v.34 no.4
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• pp.359-366
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• 2001

Studies were carried out to explore the influence of dietary protein level on bone metabolism in uninephrectomized rat (experimental renal failure model) when dietary Ca and P contents were equal. Male rats were uninephrectomized or sham operated and fed 8%, 15% and 40% casein diets for 24 weeks. Ca and P contents of the all diet were 0.4% and 0.6% respectively. The results are summarized as follows. We did not found any significant difference in PTH and Ca level of the serum, Ca intake and Ca excretion among the experimental groups. There was significant positive correlation between the PTH and phosphate level. There was significant inverse correlation between serum Ca and creatinine level. The effect of the dietary protein level and renal mass loss on density and Ca contents of the bone were small and different according to the kinds of the bone. Low protein diet was associated with a significant enhancement of scapular density. Femur and vertebra density, however, were not influenced by dietary protein level and uninephrectomy. Light microscopic examination showed several calcified foci in the kidney in all experimental groups. Low protein diets have been used for a long time in the conservative management of chronic renal failure as they have a beneficial effect in preventing the appearance of symptoms. This study elucidated that part of beneficial effects of the low protein diet related to the suppression of the hyperphosphatemia. And these results, even though uninephrectomized rats fed high protein diet, the secondary hyperparathyroidism is supressed by the regulation of the P level. Therefore this study emphasized the need to pay more attention to the regulation of dietary P level as well as dietary protein content in chronic renal failure. (Korean J Nutrition 34(4): 359∼366, 2001)

• Bulletin of the Korean Chemical Society
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• v.34 no.6
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• pp.1673-1678
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• 2013

Lumazine protein is a member of the riboflavin synthase superfamily and the intense fluorescence is caused by non-covalently bound to 6,7-dimethyl 8-ribityllumazine. To figure out the binding modes and the structure of the N-terminal domain of lumazine protein, the wild type of protein extending to amino acid 118 (N-LumP 118 Wt) and mutants of N-LumP 118 V41W, S48W, T50W, D64W, and A66W from Photobacterium leiognathi were purified. The biochemical properties of the wild type and mutants of N-LumP 118 proteins were analyzed by absorbance and fluorescence spectroscope. The peak of absorbance and fluorescence of lumazine ligand were shifted to longer wavelength on binding to N-LumPs. The observed absorbance value at 410 nm of lumazine bound to N-LumP 118 proteins indicate that one mole of N-LumP 118 proteins bind to one mole of ligand of lumazine. Fluorescence analysis show that the maximum peak of fluorescence of N-LumP S48W was shifted to the longest wavelength by binding with 6,7-dimethyl 8-ribityllumazine and was shown to the greatest quench effect by acrylamide among all tryptophan mutants.

• Fisheries and Aquatic Sciences
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• v.21 no.10
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• pp.30.1-30.6
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• 2018

A study of three feeding trials was conducted to investigate the dietary protein requirements of Pacific white shrimp (Litopenaeus vannamei) at three different growth stages. Six experimental diets were formulated to include increasing protein levels of 25, 30, 35, 40, 45, and 50% (designated as P25, P30, P35, P40, P45, and P50, respectively) for three feeding trials. The three feeding trials were conducted in different-sized shrimp at 0.65 g (trial 1), 4.80 g (trial 2), and 10.5 g (trial 3). Triplicate groups of shrimp were fed one of the experimental diets for 36, 42, and 48 days in trials 1, 2, and 3, respectively. In trial 1, the growth performance was not affected by the dietary protein levels. However, protein efficiency ratio was significantly higher in P30 diet compared to P40, P45, and P50 diets. In trial 2, growth rate was significantly higher in P35 diet than in P25 diet. In trial 3, the lowest growth performance was obtained in P25 diet which significantly differed from that of other experimental diets. Broken line analysis of growth data indicates that the optimal dietary level of crude protein is 34.5, 35.6, and 32.2% for small-, medium-, and large-sized (juvenile, sub-adult, and adult stages) Pacific white shrimp, respectively.

• Asian-Australasian Journal of Animal Sciences
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• v.12 no.6
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• pp.923-931
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• 1999

An experiment was conducted to determine the effect of lysine on performance and carcass composition of broilers under heat stress during the grower period (3-6 weeks). A factorial arrangement of three levels of dietary protein (18, 20, and 22%), three levels of dietary lysine (1.26, 1.39, and 1.52%), and two rearing temperature regimens were used in this study. Birds were kept under either moderate temperature ($24{\pm}1^{\circ}C/24h$) or hot cycling temperature ($26-34^{\circ}C/6h$, $34{\pm}1^{\circ}C/12h$, and $34-26^{\circ}C/6h$). Body weight (BW), weight gain (WG), feed intake (FI), feed conversion (FE), carcass weight (CW), carcass yield (CY), and percentages of breast meat (BM), abdominal fat (AF), drumsticks (DS), and thighs (TH) were determined at the end of experiment. Exposure to high ambient temperature significantly (p<0.05) decreased BW, WG, FI, FE, CW, BM, AF, and increased CY, DS, and TH. High dietary protein significantly (p<0.05) decreased AF and TH, and improved CW only under moderate temperature, resulting in significant (p<0.05) protein by temperature interaction. High dietary lysine significantly (p<0.05) decreased BW, WG, FI, CW, CY and AF, while BM was reduced only when high dietary protein was fed, resulting in significant (p<0.05) protein by lysine interaction. It is concluded that increasing dietary lysine adversely affected broilers' performance and carcass composition irrespective of rearing temperature.

• Korean Journal of Poultry Science
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• v.43 no.4
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• pp.213-218
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• 2016

This study was conducted to investigate the effect of taurine supplementation on heat shock protein 70 and in vitro protein turnover in broiler chicks under chronic heat stress. Chicks were allocated into 3 groups of 10 birds per group; the control group was maintained at a temperature of $24^{\circ}C$ without taurine (CO group), the heat-stressed group maintained at a temperature of $34^{\circ}C$ without taurine (HO group), and heat-stressed group maintained at a temperature of $34^{\circ}C$ with taurine (HT group). The final body and liver weights of broilers in the HO and HT groups were significantly lower than those of broilers in the CO group (P<0.05). However, these parameters of the broilers in the HT group were significantly higher than those of broilers in the HO group (P<0.05). The heat shock protein 70 (hsp70) concentration in the liver of broilers in the HO group was significantly higher than that of broilers in the CO and HT groups, but the hsp70 concentration in the liver of broilers in the HT group was not different from that of broilers in the CO group. Liver homogenates of 21 day-old broilers were incubated at temperatures of $37^{\circ}C$ and $45^{\circ}C$ to prove the effect of high temperature and taurine on total protein syntheses. Neither high temperature nor taurine supplementation affected protein syntheses in liver homogenates of the broilers. However, the more the temperature increased, the more the degradation rates of cytoplasmic protein in liver homogenates increased; however, taurine supplementation had no effects on the protein syntheses in the liver of the broiler. It is possible that taurine indirectly affected protein turnover via various physiological mechanisms.

• Korean Journal of Food Science and Technology
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• v.24 no.3
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• pp.284-288
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• 1992

This study was undertaken to investigate the effect of pH and phytate level on the solubility of the protein due to binding between phytate and low-phytate rapeseed protein isolate by means of SDS-polyacrylamide gel electrophoresis. Results showed that the number of protein bands decreased by the increasing amount of phytate added to the soluble extract at pH 2.0 and 5.0 whereas there was no change at pH 11.5. Among 18 bands of rapeseed proteins at pH 2.0, seven bands (105.8, 52.3, 37.3, 34.8, 26.3, 21.3, 18.4 KDa) were removed by precipitation with 100 mg phytate addition and six bands (78.8, 46.5, 19.4, 16.8, 11.7, 8.5 KDa) further disappeared by 150 mg phytate addition. Among 15 bands at pH 5.0, only four bands disappeared by phytate addition. It is suggested that the functionality of rapeseed protein isolate can be improved by lowering the phytate content.

• IMMUNE NETWORK
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• v.2 no.1
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• pp.35-40
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• 2002

Background: CTLA-4 (Cytotoxic T Lymphocyte associated Antigen 4, CD152) has been known as a homologue of CD28, an accessory molecule providing a key costimulatory signal for successful antigen-driven activations of T lymphocyte. Most of biochemical and cell biological characteristics of the CD152 protein remain unknown while those of CD28 have been characterized in detail. Methods: In this study CD152 expression in both $CD4^+$ and $CD8^+$ PBLs was studied by using flow cytometry. And intracellular CD152 multiprotein complex was purified and used for generating antibodies recognizing proteins composing of intracellular CTLA-4 multi protein complex. Results: Level of surface expression of this molecule was peaked at 2 days of PHA stimulation in flow cytometric analysis. 40~45% of PHA blast cells were $CD152^+$ in both of two subsets at this stage and the level of expression were equivalent in both two subsets. Contrary to this surface expression, intracellular expression was peaked at day 3 and it was preferentially induced in $CD8^+$ cells and about 60% of $CD8^+$ cells were $CD152^+$ at this stage. High molecular weight (>350 kD) intacellular CD152 protein complex purified by using preparative electrophoresis were immunized into rabbits and then 3 different anti-P34PC4, anti-P34PC7 and anti-P34PC8 antibodies were obtained. Using these 3 antibodies two unknown antigens associated with intracellular CD152 multiprotein complex were found and their molecular weights were 54 kD and 75 kD, respectively. Among these, the former was present as 110 kD homodimer in non-reducing condition. Conclusion: It seemed that 34 kD intracellular CD152 molecule forms high molecular weight multiprotein complex at least with 2 proteins of 75 kD monomer and 110 kD homodimer.

• Korean Journal of Microbiology
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• v.39 no.2
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• pp.83-88
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• 2003

We cloned a gene encoding acetyl xylan esterase(axeA) of Streptomyces coelicolor A3(2) and studied its expression pattern in Escherichia coli. The full sequence of axeA was amplified by PCR. Sequence analysis of the PCR product revealed an open reading frame of 1,008 nucleotides encoding a protein consisted of 335 amino acid residues, with a calculated molecular mass of about 38 kDa. The base sequence showed 98% homology to the same gene of Streptomyces lividans. Two different kinds of acetyl xylan esterases were produced in Escherichia coli(pLacI) by IPTG induction; their molecular weights were 38 kDa and 34 kDa, respectively. Of these, 38 kDa protein seemed to be a total protein holding N-terminal signal peptide region, whereas 34 kDa protein seemed to be a matured protein without signal peptide which was produced by peptide bond cleavage between two amino acid residues of alanine 41 and alanine 42.

• Food Science of Animal Resources
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• v.34 no.3
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• pp.307-315
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• 2014

pH adjustment would be of advantage in improving the water holding capacity of muscle proteins. The objective of this study was to evaluate the addition of fish sarcoplasmic protein (SP) solution, which was adjusted to pH 3.0 or 12.0, neutralized to pH 7.0, and lyophilized to obtain the acid- and alkaline-treated SP samples, on the functional properties of the chicken myofibrillar protein induced by microbial transglutaminase (MTG). The solubility of alkaline-treated SP was higher than that of the acid counterpart; however, those values of the two pH-treated samples were lower than that of normal SP (p<0.05). All SP solutions were mixed with myofibrillar proteins (MP) extracted from chicken breast, and incubated with MTG. The shear stresses of MP with acid- and alkaline-treated SP were higher than that of normal SP. The thermal stability of MP mixture reduced upon adding SP, regardless of the pH treatment. The breaking force of MP gels with acid-treated SP increased more than those of alkaline-treated SP, while normal SP showed the highest value. The MP gel lightness increased, but cooking loss reduced, with the addition of SP. Smooth microstructure of the gel surface was observed. These results indicated that adjusting the pH of SP improved the water holding capacity of chicken myofibrillar proteins induced by MTG.

• Food Science of Animal Resources
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• v.34 no.2
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• pp.192-199
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• 2014

The effects of adding mechanically deboned chicken (MDC) hydrolysates on the quality characteristics of imitation crab stick (ICS) during storage were investigated. ICS was prepared from Alaska Pollack, chicken breast surimi, and protein hydrolysates enzymatically extracted from MDC. ICS samples were divided into 4 groups: without protein hydrolysate (control), added with 0.5% protein hydrolysate (T1), added with 1.0% protein hydrolysate (T2), and added with 1.5% protein hydrolysate (T3). Results showed that crude protein content did not differ significantly among the ICS samples (p>0.05). ICS sample added with MDC hydrolysates had higher crude fat and ash content but lower moisture content than the control (p<0.05). Lightness was significantly lower in T2 and T3 than in the other groups at 0 and 4 wk of storage. Also, whiteness decreased in the groups contained MDC hydrolysates. Breaking force and jelly strength were higher in samples containing MDC hydrolysates compared to control samples (p<0.05). Additionally, saturated fatty acid contents were lower in the groups containing MDC hydrolysates than in control sample groups (p<0.05). Polyunsaturated fatty acid (PUFA) and essential fatty acids (EFA) were significantly higher in T2 and T3 than the control samples. In particular, all samples containing MDC hydrolysates had reduced thiobarbituric acid-reactive substances (TBARS) values at 4 wk. Free radical scavenging activity also was increased with addition of MDC hydrolysates.