• Analytical Science and Technology
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• v.30 no.2
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• pp.96-101
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• 2017

This study investigated the effect of centrifugation on tryptic digestion. This was done by applying different centrifugation speeds (6,000, 8,000, 10,000, 20,000, and $30,000{\times}g$) over various durations (0, 10, 20, 30, 40, 50, and 60 min) to digest two model proteins - cytochrome c and myoglobin. The intact proteins and resulting peptides were identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Centrifugation greatly improved the tryptic digestion efficiency of cytochrome c, where either an increase in centrifugation speed or in digestion duration significantly improved the digestion of cytochrome c. However, centrifugation did not noticeably improve the digestion of myoglobin; 16 h of centrifuge-assisted tryptic digestion at $30,000{\times}g$ barely removed the myoglobin protein peak. Similar results were also obtained when using conventional tryptic digestion with gentle mixing. When acetonitrile (ACN) was added to make 10% ACN buffer solutions, the myoglobin protein peak disappeared after 6 h of digestion using both centrifuge-assisted and conventional tryptic digestions.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.12
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• pp.1728-1733
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• 2001

An experiment was conducted at the experimental duck farm of Cantho University in the Mekong Delta of Vietnam to evaluate the effects of offering pairwise feeds with different crude protein (CP) levels to Cherry Valley broiler ducks from 28-63 days of age on feed intake and performance. Five diets consisting of mixtures of soya bean meal, fish meal, maize meal and fine rice bran, were formulated to give isocaloric diets with 30, 24, 18, 16 and 12% CP. These were offered separately as pellets to growing ducklings in the following combinations: 30+18, 30+12, 24+16 and 18+12. A diet with 20% CP (CP20) was used as control. All the diets were offered ad libitum. Daily feed intakes (g dry matter, DM) were 161, 168, 150, 101 and 143 g for the 30+18, 30+12, 24+16, 18+12 and CP20 treatments, respectively. CP intakes were 29.6, 27.0, 24.8, 17.1 and 22.9% of total DM intake, and the ratio of methionine+cystine to lysine was 0.76, 0.75, 0.75, 0.76 and 0.75 for the 30+18, 30+12, 24+16, 18+12 and CP20 treatments, respectively. Live weights at 63 days of age were 2,937, 3,054, 2,898, 2,200, and 2,811 g (p<0.001), and daily live weight gains 57.8, 61.7, 57.0, 38.5 and 55.7 g (p<0.001) for the 30+18, 30+12, 24+16, 18+12 and CP20 treatments, respectively. The weights and yields of the carcass, breast and thigh muscles, and heart decreased in the order 30+18, 30+12, 24+16, CP20 and 18+12 (p<0.001). The present study suggests that growing broiler offered a combination of high and low protein feeds pairwise will eat excessive amounts of the high protein feed, thus resulting in protein intakes above requirements.

• Korean Journal of Environmental Agriculture
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• v.11 no.1
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• pp.67-76
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• 1992

A mechanistic study by which Cadmium-tolerant P.Putida C1 accumulates high conc of Cd in its cell body was performed. Approximately 57% Cd accumulated was distributed on the cell wall and the other 43% portion was in cytoplasm. 84% Cd of the Cd in the cell wall fractions present in the polyphosphate-polysaccharide fractions, but most of Cd in the cytoplasm fraction was in protein and nucleic acid. Cadmium affected the protein synthesis in P. Putida. The intracellular protein content was decreased by cadmium addition, but the soluble protein precipitated by ammonium sulfate($30{\sim}75%$ satruation) was increased as compared to that from the cells grwon without cadmium. Furthermore, in the cells grown with of cadmium, high-molecular-weight soluble protein was increased, with of cadmium, high-molecular-weight soluble protein was increased, compared with the cells grown without cadmium, but low-molecular-weight soluble protein was decreased. These results indicate that Cd inhibited the intracellular protein biosynthesis but enhance biosynthesis of the high-molecular-weight soluble protein precipitate by ammonium sulfate($30{\sim}75%$ saturation).

• Journal of Microbiology and Biotechnology
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• v.6 no.6
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• pp.451-455
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• 1996

Physiological studies on the expression of Bacillus thuringiensis subsp. tenebrionis (Btt) gene coding for insecticidal protein in recombinant Escherichia coli 537 were carried out to identify optimal culture condition. It was necessary to shift culture temperature from 30 to $42^{\circ}C$ to express the gene. Expression of the Btt toxin gene by recombinant E. coli 537 began within one hour after induction. Complex nitrogen sources increased production of the insecticidal protein. The total insecticidal protein was 0.5 g/I when using yeast extract as a complex nitrogen source. Soybean hydrolysate showed apparently the highest induction efficiency. After induction, the cellular content of the insecticidal protein was 5.4 times higher than it had been before induction. The optimal cultivation strategy was found to grow cells for 7hours at $30^{\circ}C$ and then 5-8 hours at $42^{\circ}C$. The optimal cultivation pH for the production of insecticidal protein was 6.5. The Btt toxin produced by the recombinant E. coli 537 was found to have the same level of potency against Colorado potato beetle as the original toxin.

• Korean Journal of Environmental Agriculture
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• v.20 no.5
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• pp.310-316
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• 2001

To find out the effect of low temperature on the regulation of tomato chloroplast genes, the optimization of the system in chloroplast protein synthesis and the identification of the changes in chloroplast protein synthesis induced by chilling were studied. Incorporation reaction occurred rapidly at the first 30 minutes and was constantly maintained after 60 minutes. A broad optimal temperature on protein synthesis was found around 20 to $30^{\circ}C$. No difference was shown in the chloroplast protein synthesis under high light intensity (1600 ${\mu}E/m^2/s$) as well as under low light intensity (400 ${\mu}E/m^2/s$) even darkness. $K^+$, $Mg^{++}$ and ATP at an optimal concentration act as an activator, while DTT, chloramphenicol, cycloheximide, $Ca^{++}$ and inorganic phosphate act as an inhibitor in the chloroplast protein synthesis. Synthesis of 15, 55 and 60 kd chloroplast encoded stromal proteins and 18, 24, 33 and 55 kd chloroplast encoded thylakoid membrane proteins were reduced by chilling, while 17 kd chloroplast encoded stromal protein and 16 kd chloroplast encoded thylakoid membrane protein was induced by chilling. It was expected that the 55 kd stromal protein would be the large subunit of rubisco and the 33 kd thylakoid membrane protein would be the D1 protein which was drastically reduced by chilling.

• Journal of Animal Science and Technology
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• v.47 no.6
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• pp.1001-1008
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• 2005

This study examined the effect of corn processing with varying rumen undegradable protein (RUP) on feed intake, milk yield, its composition and, blood characteristics in Holstein cows during the transitional period (21 days pre partum to 21 days post partum). Twenty Holstein cows were randomly assigned to four diets (five cows/diet), ground corn with 30 % RUP (GCR30), ground corn with 40 % RUP (GCR40), flaked corn with 30 % RUP (FCR30), and flaked corn with 40 % RUP (FCR40). The processed corn with varying RUP was fed in total mixed rations (TMR) to cows. Dry matter intake (DMI) was higher with 40 % RUP diet than with 30 % RUP diet, resulting in higher protein and energy intake by cows during pre and post partum (p＜0.05). However, it was not affected by corn processing during pre and post partum. Similarly milk yield was higher with 40 % RUP diet than with 30 % RUP diet. and milk yield was affected by corn processing at RUP 30 % level. Corn processing did not affected the milk fat and protein contents in dairy cows. The concentration of blood non esterified fatty acid (NEFA) were effected by RUP level with flaked corn, however, it was non-significant with RUP levels when given with ground corn. It is concluded that increasing RUP from 30 % to 40 % in iso-nitrogenous diet could increase milk yield in dairy cows during the transitional phase.

• Journal of Animal Science and Technology
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• v.52 no.5
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• pp.435-440
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• 2010

Whey protein concentrate (WPC) is widely used to increase the nutritional and functional properties of food. In this study, the physiochemical and functionality of WPC-30 hydrolysates were examined to evaluate the possibility of application in the food industry. The WPC-30 was manufactured using ultrafiltration and spray-drying, and then hydrolyzed with proteolytic enzyme including alcalase, flavourzyme, nuetrase and protamex. Enzymatic hydrolysis had a significant influence on the physicochemical properties as evident from the increased foaming capacity, solubility. Alcalase caused highest protein hydrolysis (3.26%) and the bitterness. Foaming capacity was largest in WPC-30 hydrolysate treated with flavourzyme. Protein solubility at various levels of pH was highest in protamex-treated WPC-30 hydrolysate. However, the solubility of WPC-30 hydrolysates was significantly improved in alkaline condition than in acidic and neutral conditions. The study revealed that spray dried enzyme modified WPC can be used in various functional food.

• Nutritional Sciences
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• v.8 no.1
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• pp.28-34
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• 2005

To examine the combined effects of a high-protein diet and aerobic exercise on body weight and composition and blood lipid profiles in overweight women, 30 young women were recruited and placed into three groups: The high-protein diet and exercise group (HPE), the exercise-only group (EXO) and the control group (CON) (30$\pm$3%, 27$\pm$2%, and 29$\pm$3% body fat, respectively) for an 8-week experimental period. Daily diet included 25% isolated soybean protein (>90% protein, approximately 400 kcal) combined with each subject s usual diet for the HPE group. The exercise program consisted of aerobic-type exercises undertaken >3 times/wk and for>30 min/session at 50-60% of maximal capacity. Physical fitness, body composition, serum total cholesterol (TC), high-density lipoprotein-cholesterol (HDL-C), triglycerides (TG) and glucose were measured before and after the experiment. Maximal aerobic capacity increased by the end of experiment in both the HPE (from 27.2$\pm$3.5 to 35.l$\pm$5.9 ml/kg/min, p<0.01) and EXO (from 30.3$\pm$5.4 to 33.8$\pm$3.8 mㅣ/kg/min, p<0.05) groups. Percent body fat decreased by 3.3% (p<0.01) in the HPE group and by 1.5% (p<0.05) in the EXO group by the end of the experiment, but not in the CON group. Lower back strength and agility increased only in the HPE group. In the HPE group, TC decreased from 168$\pm$20 to 155$\pm$18 mg/dL and HDL-C increased from 57$\pm$l0 to 61$\pm$9 mg/dL in HPE (p<0.01). But TC and HDL-C did not change in the EXO and CON groups. TG and glucose did not vary among the groups. Although the EXO group showed a similar outcome to that of the HPE group, a favorable change in body composition and blood lipids as well as an improvement in aerobic capacity was more marginal in the latter group.

• BMB Reports
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• v.28 no.3
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• pp.197-203
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• 1995

Famesyl protein transferase involved in the first step of post-translational modification of $p21^{ras}$ proteins transfers the famesyl moiety from famesyl pyrophosphate to a cysteine residue in $p21^{ras}$ proteins. The enzyme was first purified 30,000-fold from bovine testis by use of 30~50% ammonium sulfate fractionation, DEAE-Sephacel ion exchange chromatography, Sephacryl S-300 gel filtration chromatography, Sephacryl S-200 gel filtration chromatography, and hexapeptide (Lys-Lys-Cys-Val-Ile-Met) affinity chromatography. The molecular weight of the purified enzyme was estimated to be ~100 kDa by gel filtration and SDS-polyacrylamide gels showed two closely spaced bands of ~50 kDa protein. These indicate that the enzyme consists of two nonidentical subunits, a and 13, which have slightly different molecular weights. The enzyme was inhibited by hexapeptide (Lys-Lys-Cys-Val-Ile-Met), which acted as an alternative substrate that competed for famesylation. Kinetic analysis by measuring initial velocities showed that famesyl protein transferase is a very slow enzyme. EDTA-treated famesyl protein transferase showed little activity with $Mg^{2+}$ or $Zn^{2+}$ alone, but required both $Mg^{2+}$ and $Zn^{2+}$ for the catalytic activity.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.5
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• pp.732-739
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• 2002

Milk samples with different phenotype combination of $\{kappa}$-casein and ${\beta}$-lactoglobulin and different preheating temperatures of 30, 70, 75 and $80^{\circ}C$ were used for cheesemaking under laboratory conditions. For the 853 batches of cheese, mean composition was 59.64% total solids, 30.24% fat and 23.66% protein, and the whey contained 6.93% total solids, 0.30% fat and 0.87% protein. Least squares analysis of the data indicated that heating temperature of the milk and ${\kappa}$-CN/${\beta}$-LG phenotypes had significant effects on cheese and whey compositions. The total solids, fat and protein contents of cheese were negatively correlated with preheating temperatures of milk. Cheese from BB/BB phenotype milk had the highest and those from AA/AA phenotype milk had the lowest concentrations of total solids, fat and protein. Mean recoveries of milk components in the cheese were 53.71% of total solids, 87.15% of fat, and 80.32% of protein. For the 10 different types of milk, maximum recoveries of milk components in cheese occurred with preheating temperature of $70^{\circ}C$ or $75^{\circ}C$ and lowest recoveries occurred at $80^{\circ}C$. The whey averaged 6.94% total solids, 0.30% fat and 0.87% protein. Losses of milk components in the whey were lowest for milk preheated at $80^{\circ}C$ and for milk containing the BB/BB phenotype.