• Asian-Australasian Journal of Animal Sciences
• /
• v.10 no.4
• /
• pp.335-356
• /
• 1997

Injection of bovine growth hormone (bGH) to lactating dairy cows increases milk yield and yields of milk components including fat. It is generally believed that most of the anabolic effects derived from bGH in animal tissues are primarily mediated by IGF-1. IGF-1 is a strong anabolic peptide in the plasma of animals and exerts mitogenic and metabolic effects on target cells. Contrary to most protein hormones, the majority of IGF-1 in circulation is bound to the binding proteins (IGFBPs) which are known to be responsible for modifying the biological actions of IGF-1, thus making determinations of IGF-1 actions more difficult. On the other hand, fat is a major milk component and the greatest energy source in milk. Currently, the fat content of milk is one of the major criteria used in determining milk prices. It has been known that flavor and texture of dairy products are mainly affected by milk fat and its composition. Acetyl-CoA carboxylase (ACC) is the rate limiting enzyme which catalyzes the conversion of acetyl-CoA to malonyl-CoA for fatty acid synthesis in 1ipogenic tissues of animals including bovine lactating mammary glands. In addition to the short-tenn hormonal regulation of ACC by changes in the catalytic efficiency per enzyme molecule brought about by phosphorylation and dephosphorylation of the enzyme, the long-term hormonal regulation of ACC by changes in the number of enzyme molecules plays an essential role in control of ACC and lipogenesis. Insulin, at supraphysiological concentrations, binds to IGF-1 receptors, thereby mimicking the biological effects of IGF-1. The receptors for insulin and IGF-1 share structural and functional homology. Furthermore, epidermal growth factor increased ACC activity in rat hepatocytes and adipocytes. Therefore, it can be assumed that IGF-1 mediating bGH action may increase milk fat production by stimulation ACC with phosphorylation (short term) and/or increasing amounts of the enzyme proteins (long term). Consequently, the main purpose of this paper is to give the readers not only the galactopoietic effects of bGH, but also the insight of bGH action with regard to stimulating milk fat synthesis from the whole body to the molecular levels.

• Journal of Life Science
• /
• v.15 no.3 s.70
• /
• pp.406-414
• /
• 2005

The genetic instability of cancer cells may be related to inappropriately activated DNA repair pathways. In present study, the modulated expression of DNA-dependent protein kinase (DNA-PK), a major DNA repair protein, in human cancer metastatic cells was tested. The expressions of Ku70/80, regulatory subunit of DNA-PK, and the Ku DNA-binding activity in various highly metastatic cell lines were higher than those in each parental cell line. Also, the expression of DNA-PKcs, catalytic subunit of DNA-PK, and the kinase activity of the whole DNA-PK complex in highly metastatic cells were significantly increased as compared to those of parental cells, suggesting that the enhanced DNA repair capacity of metastatic cells could be associated with aberrant use of DNA repair, which may mediate tumor progression and metastatic potential. Increased EGFR (epidermal growth factor receptor) signaling has been associated with tumor invasion and metastasis, and the linkage between EGFR-mediated signaling and DNA-PK has been suggested. This study showed that PKI166, the new EGFR tyrosine kinase inhibitor, modulated the expressions of Ku70/80 and DNA-PKcs and also revealed the chemosensitization effect of PKI166 against metastatic cells may be in part due to inhibition of Ku70/80. These results suggest that interference in EGFR signaling by EGFR inhibitor resulted in the impairment of DNA repair activity, and thus DNA-PK could be possible molecular targets for therapy against metastatic cancer cells.

• Biomolecules & Therapeutics
• /
• v.32 no.1
• /
• pp.84-93
• /
• 2024

Rosmarinic acid (RA) is a phenolic ester that protects human keratinocytes against oxidative damage induced by ultraviolet B (UVB) exposure, however, the mechanisms underlying its effects remain unclear. This study aimed to elucidate the cell signaling mechanisms that regulate the antioxidant activity of RA and confirm its cyto-protective role. To explore the signaling mechanisms, we used the human keratinocyte cell line HaCaT and SKH1 hairless mouse skin. RA enhanced glutamate-cysteine ligase catalytic subunit (GCLC) and glutathione synthetase (GSS) expression in HaCaT cells in a dose- and time-dependent manner. Moreover, RA induced nuclear factor erythroid-2-related factor 2 (NRF2) nuclear translocation and activated the signaling kinases protein kinase B (AKT) and extracellular signal-regulated kinase (ERK). Treatment with the phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002, the ERK inhibitor U0126, and small interfering RNA (siRNA) gene silencing suppressed RA-enhanced GCLC, GSS, and NRF2 expression, respectively. Cell viability tests showed that RA significantly prevented UVB-induced cell viability decrease, whereas the glutathione (GSH) inhibitors buthionine sulfoximine, LY294002, and U0126 significantly reduced this effect. Moreover, RA protected against DNA damage and protein carbonylation, lipid peroxidation, and apoptosis caused by UVB-induced oxidative stress in a concentration-dependent manner in SKH1 hairless mouse skin tissues. These results suggest that RA protects against UVB-induced oxidative damage by activating AKT and ERK signaling to regulate NRF2 signaling and enhance GSH biosynthesis. Thus, RA treatment may be a promising approach to protect the skin from UVB-induced oxidative damage.

• Clean Technology
• /
• v.27 no.4
• /
• pp.350-358
• /
• 2021

The results of this study shows that the combustor temperature ranged from 848.27 to 1,026.80 ℃, averaging about 976.61 ℃, and the NOx concentration increased as the temperature increased. The urea usage ranged from 291.00 to 693.00 kg d^-1, averaging about 542.34 kg d^-1, and the NOx concentration decreased as the urea usage increased. Residence time was about 3.38 to 9.17 s, averaging about 5.22 s, about 2.61 times larger than the 2 s of the design details. This is 1,086 kg h^-1, averaging about 55.71%, compared to the 1,950 kg h^-1 SRF input permission standard. The combustion chamber area is constant, but the residence time is shown to increase with the decrease of exhaust gas. The O₂/CO ratio was 847.05 to 14,877.34, averaging about 3,111.30, and the NOx concentration slightly increased as the O₂/CO ratio increased. As the combustor temperature and O₂/CO ratio increased, the combustion reaction with nitrogen in the air increased and the NOx concentration slightly increased. As the urea usage and residence time increased, the NOx concentration decreased slightly with an increase in reactivity with NOx. The NOx concentration at the stack ranged from 7.88 to 34.02 ppm with an average of 19.92 ppm, and was discharged within the 60 ppm emission limit value. The NOhx emission factor was 1.058 to 1.795 kg ton^-1, averaging about 1.450 kg ton^-1. This value was about 24.87% of the maximum emission factor of 5.830 kg ton^-1 of other solid fuels. Other synthetic resins and industrial wastes were 79.80% and 43.65% compared to 1.817 kg ton^-1 and 3.322 kg ton^-1, respectively. This value was similar to 1.400 kg ton^-1 of RDF in the NIER notice (2005-9), 10.98% compared to the maximum SRF of 13.210 kg ton^-1. Therefore, the NOx emission factor had a large deviation.

• Korean Chemical Engineering Research
• /
• v.50 no.2
• /
• pp.251-256
• /
• 2012

Etherification of n-butanol to di-n-Butyl Ether was carried out over Keggin $H_{3+x}PW_{12-x}Nb_xO_{40}$ (x=0, 1, 2, 3) and $H_{6+x}P_2W_{18-x}Nb_xO_{62}$ (x=0, 1, 2, 3) Wells-Dawson heteropolyacid catalysts. Niobium-substituted Keggin and Wells-Dawson heteropolyacid catalysts with different niobium content were prepared. Successful preparation of the catalysts was confirmed by FT-IR, ICP-AES, and $^{31}P$ NMR analyses. Their acid properties were determined by $NH_3$-TPD (Temperature-Programmed Desorption) measurements. Heteropolyacid catalysts showed different acid properties depending on niobium content in both series. The correlation between acid properties of heteropolyacid catalysts and catalytic activity was then established. Acidity of Keggin and Wells-Dawson heteropolyacid catalysts decreased with increasing niobium content, and conversion of n-butanol and yield for di-n-butyl ether increased with increasing acidity of the catalysts, regardless of the identity of heteropolyacid catalysts (without heteropolyacid structural sensitivity). Thus, acidity of heteropolyacid catalysts served as an important factor determining the catalytic performance in the etherification of n-butanol to di-n-Butyl Ether.

• Polymer(Korea)
• /
• v.24 no.4
• /
• pp.437-444
• /
• 2000

Propylene polymerizations were carried out by using rac-Et(Ind)$_2$ZrCl$_2$ (Zirconocene catalyst) and a commercial third generation Ziegler-Natta catalyst in a semibatch reactor. From the polymerization reactions, the optimum reaction conditions and the physical properties of polymers produced from each catalyst system were investigated. The optimum reaction temperatures of rac-Et(Ind)$_2$ZrCl$_2$ and Ziegler-Natta catalyst were 5$0^{\circ}C$, 4$0^{\circ}C$, respectively. On the basis of the results for the produced polymer particle size distributions and the catalytic activities of polymerization reaction, the reaction temperature should be considered as an important factor for the successful polymerization reactions. Especially, the polymer was conglomerated in the higher reaction temperature. It was found that there was an upper limitation to co-catalyst concentration. Reaction rates and polymer yields rather decreased with increasing the concentration of to-catalyst, i.e., MAO and TEAl affected only polymerization activities, but the PEEB in Ziegler-Natta catalyst system affected isotactic indexes of produced polymer as well as activities. Based on these observations, the production yield seems to exhibit a first order lineal relationship to the partial pressure of monomer.

• Journal of Microbiology and Biotechnology
• /
• v.24 no.10
• /
• pp.1413-1420
• /
• 2014

Phytate is an antinutritional factor that impacts the bioavailability of essential minerals such as $Ca^{2+}$, $Mg^{2+}$, $Mn^{2+}$, $Zn^{2+}$, and $Fe^{2+}$ by forming insoluble mineral-phytate salts. These insoluble mineral-phytate salts are hydrolyzed rarely by monogastric animals, because they lack the hydrolyzing phytases and thus excrete the majority of them. The ${\beta}$-propeller phytases (BPPs) hydrolyze these insoluble mineral-phytate salts efficiently. In this study, we cloned a novel BPP gene from a marine Pseudomonas sp. This Pseudomonas BPP gene (PsBPP) had low sequence identity with other known phytases and contained an extra internal repeat domain (residues 24-279) and a typical BPP domain (residues 280-634) at the C-terminus. Structure-based sequence alignment suggested that the N-terminal repeat domain did not possess the active-site residues, whereas the C-terminal BPP domain contained multiple calcium-binding sites, which provide a favorable electrostatic environment for substrate binding and catalytic activity. Thus, we overexpressed the BPP domain from Pseudomonas sp. to potentially hydrolyze insoluble mineral-phytate salts. Purified recombinant PsBPP required $Ca^{2+}$ or $Fe^{2+}$ for phytase activity, indicating that PsBPP hydrolyzes insoluble $Fe^{2+}$-phytate or $Ca^{2+}$-phytate salts. The optimal temperature and pH for the hydrolysis of $Ca^{2+}$-phytate by PsBPP were $50^{\circ}C$ and 6.0, respectively. Biochemical and kinetic studies clearly showed that PsBPP efficiently hydrolyzed $Ca^{2+}$-phytate salts and yielded myo-inositol 2,4,6-trisphosphate and three phosphate groups as final products. Finally, we showed that PsBPP was highly effective for hydrolyzing rice bran with high phytate content. Taken together, our results suggest that PsBPP has great potential in the animal feed industry for reducing phytates.

• Korean Journal of Microbiology
• /
• v.48 no.2
• /
• pp.79-86
• /
• 2012

ErmSF is one of the Erm family proteins which catalyze S-adenosyl-$_L$-methionine dependent modification of a specific adenine residue (A2058, E. coli numbering) in bacterial 23S rRNA, thereby conferring resistance to clinically important macrolide, lincosamide and streptogramin B ($MLS_B$) antibiotics. $^{222}FXPXPXVXS^{230}$ (ErmSF numbering) sequence appears to be a consensus sequence among the Erm family. This sequence was supposed to be involved in direct interaction with the target adenine from the structural studies of Erm protein ErmC'. But in DNA methyltarnsferase M. Taq I, this interaction have been identified biochemically and from the complex structure with substrate. Arginine 223 and 227 in this sequence are not conserved among Erm proteins, but because of the basic nature of residues, it was expected to interact with RNA substrates. Two amino acid residues were replaced with Ala by site-directed mutagenesis. Two mutant proteins still maintained its activity in vivo and resistant to the antibiotic erythromycin. Compared to the wild-type ErmSF, R223A and R227A proteins retained about 50% and 88% of activity in vitro, respectively. Even though those arginine residues are not essential in the catalytic step, with their positive charge they may play an important role for RNA binding.

• Asian Pacific Journal of Cancer Prevention
• /
• v.15 no.21
• /
• pp.9327-9333
• /
• 2014

Breast cancer is the second most common cancer and second leading cause of cancer deaths in women. Phosphatidylinositol-3-kinase (PI3K)/AKT pathway mutations are associated with cancer and phosphatidylinositol-4, 5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA) gene mutations have been observed in 25-45% of breast cancer samples. Insulin growth factor binding protein-5 (IGFBP-5) can show different effects on apoptosis, cell motility and survival in breast cancer. We here aimed to determine the association between PIK3CA gene mutations and IGFBP-5 expressions for the first time in breast cancer patients. Frozen tumor samples from 101 Turkish breast cancer patients were analyzed with high resolution melting (HRM) for PIK3CA mutations (exon 9 and exon 20) and 37 HRM positive tumor samples were analyzed by DNA sequencing, mutations being found in 31. PIK3CA exon 9 mutations (Q546R, E542Q, E545K, E542K and E545D) were found in 10 tumor samples, exon 20 mutations (H1047L, H1047R, T1025T and G1049R) in 21, where only 1 tumor sample had two exon 20 mutations (T1025T and H1047R). Moreover, we detected one sample with both exon 9 (E542Q) and exon 20 (H1047R) mutations. 35% of the tumor samples with high IGFBP-5 mRNA expression and 29.4% of the tumor samples with low IGFBP-5 mRNA expression had PIK3CA mutations (p=0.9924). This is the first study of PIK3CA mutation screening results in Turkish breast cancer population using HRM analysis. This approach appears to be a very effective and reliable screening method for the PIK3CA exon 9 and 20 mutation detection. Further analysis with a greater number of samples is needed to clarify association between PIK3CA gene mutations and IGFBP-5 mRNA expression, and also clinical outcome in breast cancer patients.

• BMB Reports
• /
• v.44 no.7
• /
• pp.490-495
• /
• 2011

Transcription factor AP-$2{\alpha}$ involves in the process of mammalian embryonic development and tumorigenesis. Many studies have shown that AP-$2{\alpha}$ functions in association with other interacting proteins. In a two-hybrid screening, the regulatory subunit ${\beta}$ of protein casein kinase 2 ($CK2{\beta}$) was identified as an interacting protein of AP-$2{\alpha}$; we confirmed this interaction using in-vitro GST pull-down and in-vivo co-immunoprecipitation assays; in an endogenous co-immunoprecipitation experiment, we further found the catalytic subunit ${\alpha}$ of protein casein kinase 2 ($CK2{\alpha}$) also exists in the complex. Phosphorylation analysis revealed that AP-$2{\alpha}$ was phosphorylated by CK2 kinase majorly at the site of Ser429, and such phosphorylation could be blocked by CK2 specific inhibitor 4,5,6,7-tetrabromobenzotriazole (TBB) in a dose-dependent manner. Luciferase assays demonstrated that both $CK2{\alpha}$ and $CK2{\beta}$ enhanced the transcription activity of AP-$2{\alpha}$; moreover, $CK2{\beta}$ increased the stability of AP-$2{\alpha}$. Our data suggest a novel cellular function of CK-2 as a transcriptional co-activator of AP-$2{\alpha}$.