• Journal of Life Science
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• v.20 no.7
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• pp.1012-1018
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• 2010

The aim of this study was to determine whether Alzheimer's amyloid precursor protein (APP) is dysregulated in adipose tissues of C57BL/6 male mice by high-fat diet (HFD) induced obesity, aging, or streptozotocin (STZ)-induced diabetes. APP mRNA expression was examined by quantitative real-time PCR (QPCR) in subcutaneous (SAT) and epididymal adipose tissues (EAT) from mice in 8 different condition groups. By combining conditions of age (16 weeks/26 weeks of age), diet (normal diet (ND)/high-fat diet), and induction of diabetes (non-diabetic/diabetic), 88 mice were divided into 8 different groups. QPCR demonstrated that APP expression in SAT was significantly increased by about two-fold in HFD-induced obese mice compared to both 16 week-old and 26 week-old mice in the ND group (16 weeks p=0.001; 26 weeks p<0.0001), but no changes in EAT was found. Particular effects of aging on APP gene expression were not observed in either adipose tissue depots. Significantly decreased APP expression was found in SAT in STZ-induced diabetic mice fed on ND or HFD at 16 weeks of age (ND p<0.05; HFD p<0.01). Linear regression analysis demonstrated that APP expression levels correlated with body weight in both the non-diabetic group (R=0.657, p<0.0001, n=39) and the diabetic group (R=0.508, p=<0.0001, n=49), but did not correlate with plasma glucose levels, which suggests that decreased APP expression in STZ-induced diabetic mice is most likely due to weight loss rather than hyperglycemia. These data confirm APP dysregulation by weight changes in humans and suggest a possible role linking midlife obesity with the later development of amyloidogenesis in the brain of older patients with Alzheimer's disease.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.1
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• pp.79-86
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• 2012

This study was performed to investigate the physiochemical properties and anti-diabetic effect of yacon vinegar by two-step fermentation. Yacon was matured at room temperature for 20 days. The sugar content of yacon juice prepared from mature yacon was approximately $14^{\circ}Brix$. In the first stage, yacon wine was produced from the juice at $28^{\circ}C$ for 6 days. In the second stage, acetic acid fermentation was conducted at $30^{\circ}C$ and 200 rpm for 6 days to produce yacon vinegar with 4.75% acidity. The major free sugars of yacon vinegar were glucose and fructose at 2,072.12 mg% and 463.95 mg%, respectively. The acetic acid content was the highest of the major organic acids at 3,881.44 mg%. The total free amino acid content was 62.88 mg% with the main free amino acids being proline, ${\gamma}$-amino-n-butyric acid and ornithine. The major minerals of yacon vinegar were Ca, K and Mg. The in vivo anti-diabetic activity of yacon vinegar was investigated in high-fat diet (HFD)/streptozotocin (STZ)-induced diabetic mice. Diabetic mice were administered orally with 10% yacon juice and two yacon vinegars (5% and 10%) at a dose of 7 mL/kg body weight once per day for 4 weeks. Five% yacon vinegar improved the fasting blood glucose levels and glucose tolerance test significantly compared to the diabetic control group (p<0.05). Yacon vinegar increased the pancreatic C-peptide concentration in a dose-dependent manner. These results show that 5% yacon vinegar has a more potent effect on ameliorating hyperglycemia than 10% yacon juice.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.11
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• pp.1401-1407
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• 2008

1-Deoxynojirimycin (DNJ) is a strong $\alpha$-glucosidase inhibitor which inhibits hyperglycemia in animals. To select the Bacillus strains highly producing DNJ, 4,000 strains were isolated from soil and grain samples. By the inhibitory activity against $\alpha$-glucosidase, nine Bacillus strains were selected and then identified by 16S rDNA sequencing. B. subtilis S10 was finally selected as the best strain for the production of DNJ. Various carbon sources and nitrogen sources in culture medium were evaluated for the highest production of DNJ. As the results, the optimized concentration of carbon source and nitrogen source was 1.0% galactose and 1.6% polypeptone and the concentration of DNJ produced was 0.75 g/L. The effect of culture supernatant of B. subtilis S10 on lowering blood glucose level was investigated in streptozotocin (STZ)-induced diabetic mice model. Mice were randomly assigned to control group (saline) and three test groups such as acarbose group, silkworm powder group and B. subtilis S10 group. After eight-week oral feeding, blood glucose levels of the B. subtilis S10 and silkworm powder groups were respectively $209.1{\pm}19.6\;mg/dL$ (59.1%) and $208.6{\pm}39.8\;mg/dL$ (59.0%) lower than $510{\pm}10\;mg/dL$ of the control group. These results indicated that the culture supernatant of B. subtilis S10 was able to reduce the blood glucose level in STZ-induced diabetic mice.