Korea Research Foundation Research Articles

Maternal consumption of soy protein affects lipid metabolism in the offspring of rats

Previous studies suggest that nutrition during the fetal and neonatal periods may program susceptibility in the offspring to later development of chronic diseases, such as obesity, hypertension, CVD and diabetes. We investigated the effect of the early life consumption of soy protein and genistein on gene expression involved in metabolic syndrome phenotype. SD rats were fed a casein diet (CAS: 200 g casein/kg diet), a soy protein diet (SPI: 200 g soy protein isolate/kg), or a casein + genistein diet (GEN: 200g casein + 250 mg genistein/kg) throughout 2 week before pregnancy, pregnancy and lactation. There was no significant difference in the weights of the dams among groups throughout study periods. Male offspring were studied at 21 d after birth. The male SPI offspring had significantly lower body weight and body fat than the other groups. Serum total cholesterol concentration was significantly lower in the SPI group. The fasting serum glucose and insulin concentrations were not different among groups. Expressions of 15 genes involved in lipid, fatty acid, steroid metabolism were significantly altered in the SPI group compared to those in CAS group (|fold change| ≥ 2.0) as determined by microarray analysis. Therefore, in the present study, we observed that maternal consumption of soy protein during pre‐pregnancy, pregnancy and lactation affects lipid metabolism in the offspring of rats. This work was supported by a grant from Korea Research Foundation.

Involvements of Akt and phospholipase D‐mediated phosphatidic acid in the regulation of mTOR signaling during immobilization and remobilization of rat skeletal muscle

Skeletal muscle activity is known to determine its mass by regulating protein synthesis through Akt‐mTOR‐p70s6k signaling. It has been revealed that mTOR and its downstream signaling is also activated by phosphatidic acid (PA) in mechanically stimulated skeletal muscle. This study was conducted to investigate, during altered skeletal muscle usage, how phospholipase D (PLD)‐mediated phosphatidic acid (PA) level is modulated, and that is involved in Akt signaling to p70s6k. Eleven‐weeks‐old male rats were subjected to unilateral hindlimb immobilization (Im) for 10 days and allowed to recover by remobilization (Rm) for 3 or 13 days. Non‐immobilized muscles were served as an internal control. Immobilized gastrocnemius was significantly atrophied (muscle mass loss), but during Rm its mass had been gradually recovered. Deactivated Akt signaling to p70s6k induced by Im was also recruited by Rm. Specifically changes in activation of p70s6k were more dramatic than that of Akt during Im and Rm periods. The level of PA was reduced during Im with impaired activity of PLD. However, Rm increased the activity of PLD and level of PA, and even greater than control muscle at the 3 day. These results suggest that mTOR signaling during inactive or active skeletal muscle use may be regulated by PLD‐mediated PA level as well as Akt activation. Supported by the Korea Research Foundation (KRF‐2008‐C00071).

Self‐Sufficient Catalytic System of Cytochrome P450cam, Putidaredoxin, and Putidaredoxin Reductase Provides a Useful Cell‐based Enzymatic Reaction

The catalytic turnover of cytochrome P450cam (P450cam) from Pseudomonas putida requires two auxiliary reduction partners, the iron‐sulfur protein putiaredoxin (Pd) and the flavoprotein putidaredoxin reductase (PdR). We report the functional expression in Escherichia coli of tricistronic constructs consisting of P450cam encoded by the first cistron and the auxiliary proteins, Pd and PdR by the second and the third. The expression level of P450cam was 500 nmol per liter of culture. Transformed bacterial whole cells efficiently oxidized (1R)‐(+)‐camphor, the normal substrate of the enzyme, to 5‐exohydroxycamphor. More interestingly, this whole cells system successfully oxygenated a monoterpene, limonene, and converted it to (−)‐perillyl alcohol, an anticarcinogenic compound with limited availability. These bioengineered E. coli cells expressing three proteins possess a heterologous self‐sufficient P450 catalytic system that may have advantages in terms of low cost and high yield for the production of the fine chemicals. This study was supported by a Korea Research Foundation Grant funded by the Korean Government (MOEHRD, Basic Research Promotion Fund)(KRF‐2008‐331‐E00030)

Diet‐induced obesity leads to decreased hepatic iron storage associated with inflammation

Increased risk for iron deficiency has been reported in obese subjects. We investigated the effects of high fat diet‐induced obesity on hepatic iron status and serum adipokine and inflammatory marker levels. Four‐ week old C57BL mice were fed diets containing 10 (ND) or 60 (HFD)% energy from fat for 16 wks. Consumption of HFD resulted in higher weight gain (16.3 vs. 30.4g). Serum leptin, total adiponectin, high molecular weight (HMW) adiponectin, and serum amyloid A (SAA) and hepatic non‐heme iron, ferritin, and hepcidin mRNA levels were measured. HFD group had higher leptin (42.6 vs. 104.3 ng/mL), and lower HMW adiponectin (4.80 vs. 3.67 ug/mL) levels. Higher level of SAA in HFD group (57.8 vs. 117.9 ug/mL) suggests inflammation in HFD‐induced obese animals. HFD group had lower hepatic non‐heme iron (3.12 vs 0.869 ug/mg protein) and ferritin levels. HFD group had lower hepcidin expression at 54% level of ND group, however, ratio of hepcidin expression to non‐heme iron was higher (2.5 fold higher in HFD than ND). Hepcidin is a homeostatic regulator of iron metabolism by restricting intestinal iron absorption, but, also known as a mediator of inflammation. Leptin and SAA showed positive correlation with weight gain while HMW adiponectin showed negative correlation. Increased SAA levels and higher hepcidin ratio to iron suggests that lower hepatic iron status in obese animals might be associated with inflammation. Supported by Korea Research Foundation Grant (C00305) and by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (2009‐0063409).

공공기금으로 작성된 논문의 오픈액세스 정책에 관한 연구

This paper studied on the open access to public funded research articles in Korea. The 18% of articles published in the journals of the Korea Research Foundation was the output of research that received public fund. The field of engineering science had the most number of public funded articles and the most frequently supported funding agency was the KRF. But most of the public funded articles in Korea has been serviced through the commercial DBs, whereas the small number of articles serviced freely through the Korea Research Memory and NTIS. This paper proposed that the KRF will have to develop the open access policy focus on the engineering science.

Analysis of Research on the Nursing of Hematology in Korea

Purpose: This study was conducted in order to analyze themes, concepts, research methods and results of previous domestic research on the nursing of hematologic patients conducted through the last 10 yr, to find trends in the research, and to provide basic materials for setting the direction of future research on the nursing of hematologic patients. Methods: This study analyzed a total of 72 nursing theses related to hematology sampled from domestic theses for a master’s or doctoral degree and papers published in six nursing journals registered in Korea Research Foundation from January 2000 to July 2009. Results: Of the 72 theses, 51 were for a master’s degree, 7 for a doctoral degree, and 14 not for an academic degree. The concept covered most frequently in correlation research was ‘quality of life’ and concepts found in comparative research were stress and quality of life. In experimental research, the most common nursing intervention was oral care. The scale used most frequently was Spielberger’s Anxiety Scale. Conclusion: It is necessary to expand experimental research applying nursing interventions, and to use objective physiological indexes for more effective assessment in experimental research. Furthermore, interdisciplinary research is required for enhancing the quality of clinical nursing research.

A Drosophila Gustatory Receptor Essential for Aversive Taste and Inhibiting Male-to-Male Courtship

Contact chemosensation is required for several behaviors that promote insect survival. These include evasive behaviors such as suppression of feeding on repellent compounds, known as antifeedants, and inhibition of male-to-male courtship. However, the gustatory receptors (GRs) required for responding to nonvolatile avoidance chemicals are largely unknown. Exceptions include Drosophila GR66a and GR93a, which are required to prevent ingestion of caffeine, and GR32a, which is necessary for inhibiting male-to-male courtship. However, GR32a is dispensable for normal taste. Thus, distinct GRs may function in sensing avoidance pheromones and antifeedants. Here, we describe the requirements for GR33a, which is expressed widely in gustatory receptor neurons (GRNs) that respond to aversive chemicals. Gr33a mutant flies were impaired in avoiding all nonvolatile repellents tested, ranging from quinine to denatonium, lobeline, and caffeine. Gr33a mutant males also displayed increased male-to-male courtship, implying that it functioned in the detection of a repulsive male pheromone. In contrast to the broadly required olfactory receptor (OR) OR83b, which is essential for trafficking other ORs, GR66a and GR93a are localized normally in Gr33a mutant GRNs. Thus, rather than regulating GR trafficking, GR33a may be a coreceptor required for sensing all nonvolatile repulsive chemicals, including tastants and pheromones.

Stooped Nanohairs: Geometry‐Controllable, Unidirectional, Reversible, and Robust Gecko‐like Dry Adhesive

This work was supported by the Korea Science & Engineering Foundation through the NANO R&D Program (Grant 2007–02605) and the King Abdullah University of Science and Technology (KAUST) program (KUK-F1- 037-02). This work was also supported in part by the Korea Research Foundation Grant funded by the Korean Government (MOEHRD) (Grant KRF-J03000), the Micro Thermal System Research Center, and the Engineering Research Institute. Supporting Information is available online at Wiley InterScience or from the author.

The Effect of Hairtail Hydrolysate on Hydrogen Peroxide‐induced Apoptosis in Human Vascular Endothelial Cells

Hydrogen peroxide (H2O2) which is one of the reactive oxygen species has been seen to cause various disease, various cellular disinfections, gene transformation and cell death. Much same unsaturated fatty acid as linoleic acid, taurine is included in a hairtail, and effect on adult disease prevention. The present study elucidated apoptosis pathways, through which hairtail hydrolysate exerted anti‐apoptosis in endothelial cells exposed to H2O2. Hairtail hydrolysate substantially diminished the H2O2‐induced cytotoxicity and Hoechast 33258 staining suggesting the inhibition of accumulation of H2O2‐triggered ROS and consequent apoptosis. The western blot data identified that hairtail hydrolysate at 200 μg/ml promptly attenuated phosphorylation of JNK and p38 MAPK by H2O2. Furthermore, this study also attempted to explore caspase activation in H2O2‐induced endothelial apoptosis. It was found that 200 μg/ml hairtail hydrolysate rapidly attenuated the cleaved of caspase‐3, ‐6, ‐7 within 18 h. Thus, hairtail hydrolysate may acts as an anti‐apoptotic agent blocking H2O2‐induced endothelial apoptosis. This study was supported by grants of KRF F00072 and Brain Korea 21 from Korea Research Foundation and from Korea Science and Engineering through the Silver Biotechnology Research Center at Hallym University.

Roasted licorice extracts prevent chronic high glucose‐induced accumulation of glomerular mesangial matrix

Diabetic nephropathy (DN) characterized as glomerulosclerosis can cause renal failure and end‐stage renal disease. Expansion of glomerular mesangial matrix mainly comprised of type IV collagen is a prominent feature of DN. Enhanced expression and secretion of connective tissue growth factor (CTGF) contribute an important role in this process. The present study is to investigate whether roasted licorice extracts (rLE) at non‐toxic doses can inhibit production of high glucose‐induced type IV collagen as well as CTGF in human mesangial cells (HRMC). Serum starved HRMC were cultured in media containing 5.5 mM glucose plus 27.5 mM mannitol as an osmotic control or 33 mM glucose for 3 days in the presence of 10 µg/mL rLE. Exposure of HRMC to high glucose resulted in a significant increase in collagen type IV secretion and CTGF expression, which was reversed by rLE. These effects were much greater than raw licorice extracts that exhibited a weak inhibition when extracted in ethanol. Isoliquiritigenin, a bioactive component of rLE, appeared to attenuate high glucose‐stimulated mesangial matrix accumulation. The results demonstrate that rLE may be potential therapeutic agents for the prevention and treatment of diabetic nephropathy. Supported by Brain Korea 21 from Korea Research Foundation and the grant (R01‐2006‐000‐10896‐0) from Korea Science and Engineering Foundation.

The development of geriatric nutritional risk Index (GNRI) for Korean elderly

This study was performed to identify and develop GNRI for Korean elderly. Based on literature review, factors for GNRI were identified and indices were assessed by a cross‐sectional survey. The survey involved elderly women (¡Ã 60, n=94) in Gwangju area, Korea. Socio‐demographics, lifestyle characteristics, health conditions, dietary intakes, anthropometric measures, and clinical biochemistry parameters were examined relation to nutritional risk index. The risk factors related to nutritional status were abdominal fat, RBC, HbA1c, HDL‐cholesterol, and ferritin using stepwise multiple linear regression. Based on literature review and data analyses, three NRIs were identified. NRI I was related to having metabolic syndrome, NRI II was related to serum albumin and body weight, and NRI III was related to food habit and health concerns. Abdominal fat (%) of elderly was correlated with each NRIs. NRI II was correlated with nutritional deficiency and higher tendency of inflammatory response, and NRI III was correlated with nutritional status which tends to be lower on aging (protein, folate, Vit B12). (Funded by the Korea Research Foundation)

Neuroprotective effect of isoflavones against homocysteine‐mediated neuronal degeneration in SH‐SY5Y cells

Several studies reported that ER stress‐induced homocysteine (Hcy) toxicity may play an important role in the pathogenesis of neurodegeneration. Estrogen as well as isoflavones has been suggested to have the protective effect against the risk of developing neurodegenerative diseases. Therefore, in the present study, we investigated effects of isoflavones (genistein and daidzein) on Hcy‐mediated neurotoxicity in SH‐SY5Y human neuroblastoma cells. Treatment of cells with isoflavones significantly protected cells against Hcy‐mediated apoptosis. We observed significant increase in DNA damage by Hcy, which was alleviated by isoflavones. Isoflavones suppressed Hcy‐mediated ER stress as determined by decreased expressions of the binding protein (BiP) mRNA, spliced X‐box‐protein (Xbp)‐1 mRNAs and C/EBP homologous transcription factor (CHOP) protein. Treatment of cells with isoflavones also significantly inactivated GSK3β and decreased tau hyperphosphorylation. In conclusion, our results demonstrate that isoflavones may alleviate ER stress‐mediated neurodegeneration. This study was supported by a grant from Korea Research Foundation.

Evaluation of manganese balance status in Korean adults

Few data are available to establish recommendations for manganese in Korea. This study assessed the status of manganese balance among 51 free‐living Korean adults. We measured dietary manganese intake using 3‐day dietary records, and analyzed the manganese contents in 24 hr urine, feces and serum of the subjects. Average age, height, weight and body mass index were 24.7 years, 173.2 cm, 73.6 kg and 24.6 kg/m2 in males and 22.8 years, 160.8 cm, 55.5 kg and 21.6 kg/m2 in females. The daily manganese intakes of male and female subjects were 3.2 mg and 3.7 mg, respectively. Average serum manganese level was 10.49 ug/dl in male and 6.11 ug/dl in females, and there was no significant difference. Urinary manganese excretion in male (344.5 ug/day) was significantly higher than that in female (184.7 ug/day). However, fecal manganese excretion was not significantly different between male (2078.0 ug/day) and female (1950.6 ug/day). Also, retention, retention rate and apparent digestibility of manganese were 765.6 ug/day, 18.4% and 30.9% for male, and 596.6 ug/day, 19.4% and 26.0% for female, it turned out that there was no significant difference. By continuous evaluating balance status of manganese, it is anticipated that reference intakes of manganese will be established. <'This work was supported by the Korea Research Foundation Grant funded by the Korean Government (KRF‐2006‐531‐C00069).'>

Differential gene expression profiles in the spontaneously hypertensive rats administrated with anti-hypertensive drugs (93.20)

Abstract To identify and characterize the genes involved in the functional regulation of hypertension and arteriosclerosis-specific genes, changes in gene expression profiles were examined by DNA microarray from the spontaneously hypertensive rats (SHR) and normal the Wistar-Kyoto (WKY) rats after administration with anti-hypertension drugs, including angiotensin I-converting enzyme (ACE) inhibitor, enalapril and the calcium channel blocker, nifedifine. Among the genes that were distinct and differentially expressed in brain, heart and liver of SHR rats administrated with the drugs, 113 were specifically up-regulated, and 102 were down-regulated genes compared to those of WKY or SHR rats. The differential gene expression profiles in DNA microarray were corroborated by semi-quantitative RT-PCR. Of these genes, expression of TNFSF4, 6, 10, IL-6 receptor, IL-18 receptor accessory protein and CD24 genes was extensively exhibited in a hypertension-specific manner, and patterns for hypertension-associated gene expression was regulated by changes of their expression in angiotensin ¥± or H2O2-treated vascular smooth muscle cells. These results will provide a fundamental basis to delineate the novel mechanisms, and a thorough investigation of the relationship between their expression and function will provide a better understanding in the development of new therapeutic drugs against cardiovascular diseases. This work was supported by the Korea Research Foundation Grant funded by the Korean Government (MOEHRD) (KRF-2006-005-J03003)

Green tea (GT) extract enhances the biliary secretion of benzo[a]pyrene (BaP) in rats

Recently, we have shown that GT extract (GTE) lowers significantly the lymphatic absorption of BaP in rats. The present study was conducted to examine the effect of GTE on the biliary secretion of BaP in rats. Female rats were fed an AIN‐93G diet with or without (control) GTE at 5 g/kg diet for 4 wk. At 4 wk, rats with bile cannulae were infused at 3.0 mL/h for 8 h via a duodenal catheter with a lipid emulsion containing 1.0 mg BaP labeled with 14C (14C‐BaP), 452 μmol triolein, 20.7 μmol cholesterol, and 3.1 μmol α‐tocopherol (αTP), and 396.0 μmol Na‐taurocholate in PBS buffer (pH, 6.4). Bile was collected via a bile cannula hourly for 8 h. No significant difference was observed in bile flow for 8 h between the groups. However, the biliary secretion of 14C‐BaP was significantly increased in rats fed GTE, compared with controls. The rates of 14C‐BaP secretion for 8 h were 24.24 ± 0.43 %dose in rats without GTE and 31.51 ± 0.83 %dose in rats with GTE. The results indicate that GTE has a stimulatory effect on the biliary secretion of BaP in rats. The mechanism(s) by which GTE increases BaP secretion remains to be determined. Supported by the Korea Research Foundation Grant funded by Korean Government (MOEHRD, Basic Research Promotion Fund) (KRF‐2006‐003‐C00312)

Calcium hydroxide attenuates inflammatory potential of lipoteichoic acid from Enterococcus faecalis (135.33)

Abstract Enterococcus faecalis is a pathogenic gram-positive bacterium closely related with refractory apical periodontitis. Since lipoteichoic acid (LTA) is a major virulence factor of gram-positive bacteria, we prepared highly pure LTA from E. faecalis and investigated its inflammatory responses in a murine macrophage-like cell line, RAW 264.7. Upon exposure to E. faecalis LTA, RAW 264.7 cells substantially produced tumor necrosis factor-α (TNF-α) in concentration- and time-dependent manner. Notably, the LTA was able to stimulate Toll-like receptor 2 (TLR2), but not TLR4. Concomitantly, LTA enhanced the DNA-binding activity of a transcription factor, NF-κB, which plays an important role in the transcriptional activation of genes encoding inflammatory mediators. However, induction of TNF-α production was not observed in the cells exposed to LTA pre-treated with calcium hydroxide, which is widely used endodontic medicament for eliminating viable bacteria and inactivating virulence factors. Furthermore, calcium hydroxide-treated LTA was not able to stimulate TLR2. These results suggest that E. faecalis LTA could stimulate inflammatory responses through TLR2 and calcium hydroxide could detoxify LTA, resulting in attenuation of the inflammatory responses. Supported by the Korea Research Foundation Grant (KRF-2007-314-E00186).

The effect of silicon supplementation on bone mineral density relative to Ca intake levels in ovariectomized rats

The purpose of this study was to investigate the effect of silicon (Si) supplementation on bone mineral density (BMD) and bone metabolism parameters relative to Ca intake levels in ovariectomized rats. A total of 72 female Wistar rats (six weeks) were ovariectomized (OVX) and divided into six groups, and Si (500 mg of Si per kg of feed) was or was not administered with diets containing various levels of Ca (0.1%, 0.5%, 1.5%) for ten weeks. Si supplementation significantly increased the BMD of the femur and tibia in Ca‐deficient OVX rats, while no change was observed with Si supplementation in the BMD of the spine, femur and tibia in the adequate and high Ca groups. Serum ALP and osteocalcin levels were not affected by Si supplementation or Ca intake levels. CTX levels were significantly decreased as a result of Si supplementation in Ca‐deficient OVX rats. In summary, Si supplementation produced positive effects on bone mineral density in Ca‐deficient OVX rats by reducing bone resorption. Therefore, Si supplementation may also prove to be helpful in preventing osteoporosis in postmenopausal women whose calcium intake is insufficient. <'This work was supported by the Korea Research Foundation Grant funded by the Korean Government (KRF‐2006‐331‐C00315)'>

Stereoselective Synthesis of the Southern Domain of Tubelactomicin A by a Tandem Intramolecular Diels-Alder/Lactonization Reaction

This work was supported by a Korea Research Foundation Grant funded by the Korean Government (MOEHRD) (KRF-2005-070-C00073, KRF-2008-331-C00160) and by a Korea Science and Engineering Foundation (KOSEF) grant funded by the Korea government (MEST) (No. R01- 2008-000-11094-0) and by KBSI grant (N28043) to G.-S. Hwang.

Therapeutic Implication of Botulinum Toxin B for Treatment of Muscle Hypertrophy from In Vivo Study

This work was supported by the Korea Research Foundation Grant funded by the Korean Government(MOEHRD) (KRF-2005-003-E00204).

Cleavage of the Wnt Receptor Ryk Regulates Neuronal Differentiation during Cortical Neurogenesis

Ryk is a transmembrane receptor tyrosine kinase (RTK). It functions as a receptor of Wnt proteins required for cell-fate determination, axon guidance, and neurite outgrowth in different organisms; however, the molecular mechanism of Ryk signaling is unknown. Here, we show that Ryk is cleaved, permitting the intracellular C-terminal fragment of Ryk to translocate to the nucleus in response to Wnt3 stimulation. We also show that the cleaved intracellular domain of Ryk is required for Wnt3-induced neuronal differentiation in vitro and in vivo. These results demonstrate an unexpected mechanism of signal transduction for Ryk as a Wnt receptor, in which the intracellular domain itself functions as the transducing molecule to bring extracellular signals from the cell surface into the nucleus, to regulate neural progenitor cell differentiation.