松田 寛子

(-)-Epigallocatechin-3-O-gallate (EGCg), the major catechin responsible for the health-enhancing and disease-preventive effects of green tea, is susceptible to auto-oxidation at physiological pH levels. However, whether the oxidized EGCg resulting from its oral consumption possesses any bioactive functions remains unclear. This study presents a differential analysis of intact and oxidized EGCg regarding their interactions with phosphatidylcholine liposomes, serving as a simple biomembrane model. In the presence of ascorbic acid, pre-oxidized EGCg induced liposomal aggregation in a dose-dependent manner, whereas intact EGCg did not. Toxicity evaluation using calcein-loaded liposomes revealed that liposomal aggregation is associated with minimal membrane damage. Through fractionation of the oxidized EGCg sample, the fraction containing theasinensins showed high liposomal aggregation activity. Overall, these results suggest that oxidatively condensed EGCg dimers may stimulate various cells by altering the plasma membrane in a manner different from that of EGCg monomers.

The microbiological properties of Myanmar traditional fermented products were characterized using four different brands of bottled shrimp sauce products sold frequently at a large grocery market. Viable cells of these products were detected at various levels (10(2)-10(5) cfu/ml) using de Man, Rogosa and Sharpe (MRS) agar medium containing 10% NaCl, and all isolates from the product samples were identified as the halophilic lactic acid bacterium Tetragenococcus muriaticus by 16S rRNA gene analysis. On the other hand, culture-independent bacterial analysis using a combination of clone library analysis and terminal restriction fragment length polymorphism (T-RFLP) analysis targeting the 16S rRNA gene demonstrated that these bacterial communities can be classified into three types. In two shrimp sauce products, a strictly anaerobic non-spore-forming halophile belonging to the genus Halanaerobium was detected as the dominant bacterium. In one shrimp sauce product, Tetragenococcus was the dominant genus. However, in the remaining shrimp sauce product, a number of bacterial species typically found in various environments, including the genera Geosporobacter, Sporohalobacter, Lysinibacillus, Soehngenia, and Tepidiphilus, were detected. These findings suggest that typical fermentation bacterial species found in traditional fermented fishery products, such as those belonging to the genera Tetragenococcus and Halanaerobium, are also frequently found in Myanmar shrimp sauce products.

Green-plant membrane is a phytonutrient present in green leafy vegetables at high concentration. Postprandial increases in blood triglyceride levels result in insulin resistance and type 2 diabetes. Additionally, dietary life and eating order also affect postprandial hypertriglyceridemia. In this study, the effects of once-daily intake of green-plant membrane with dietary oil on postprandial hypertriglyceridemia were investigated in vitro and in vivo. In vitro, green-plant membrane bound hydrophobic bile acids but did not inhibit pancreatic lipase activity. Following the administration, green-plant membrane with dietary oil in rats, oral fat tolerance tests, increases in serum triglycerides levels were significantly reduced. Moreover, fecal total lipid and bile acid volumes were significantly increased in rats that administered 200 mg/ mL green-plant membrane. These results suggest that green-plant membrane with dietary oil inhibits dietary fat absorption via promotion of bile acid excretion in feces and the effectiveness of eating green-plant membrane, such as green leafy vegetables, with meals.

<p>Potatoes are generally regarded as high glycemic index (GI) foods. Resistant starch (RS) comprises the starch fraction that is not absorbed in the small intestine, thus controlling the glucose level and improving the intestinal environment. In this study, an analysis of the formation of RS of potato starch samples under different acetic acid-thermal treatment conditions was conducted. Additionally, the relationship between the rates of starch digestion, estimated GI (eGI), and the RS content was evaluated by employing in vitro enzymatic models. Compared with control samples, the RS content in the cold-stored samples after acid-boiling was higher, whereas that of samples after heating at 120 °C with acetic acid was decreased. The eGI was negatively correlated with the RS content in potatoes. Cold store after acid-boiling was effective in increasing the RS content. Furthermore, low eGI values may have resulted from higher levels of RS in potatoes.</p>

<p> The postprandial increase in blood triglyceride levels is an independent risk factor for coronary artery disease and a large number of studies has shown that a diet rich in vegetables may provide protection against many chronic diseases. Leaf vegetables generally contain β-carotene, zeaxanthin and chlorophyll including thylakoids. In this study, we investigated the bile acid-binding capacities of thylakoids in vitro and the suppressive effects of it before the administration of a lipid meal on postprandial hypertriglyceridemia in rats using oral fat tolerance/loading tests (OFTT). Consequently, thylakoids bound bile acids in a dose-dependent manner. Following the administration of the lipid meals, increases in the serum triglycerides levels were significantly reduced in rats fed 300 mg/kg bw of thylakoids just before lipid meals. Additionally, the area under the curve showed that a high-dose thylakoids significantly inhibited the absorption of dietary fat. Moreover, the level of fecal bile acid was significantly increased although there were no significant differences in the fecal volume and fecal total lipid levels.</p><p> These results suggest that thylakoid intake before eating a lipid diet induces a suppressive effect of postprandial hypertriglyceridemia to defecate bile acid and confirmed the results of the health-promoting potential dietary thylakoids. This health benefit of thylakoids could be achieved by substantially increasing the consumption of vegetables.</p>

Postprandial increase in blood triglyceride levels is an independent risk factor for coronary artery disease, and dietary resistant starch (RS) is increasingly being considered for its contribution to disease prevention. Specifically, RS has beneficial effects on of the glycemic index, diabetes, cholesterol levels, and weight management. However, the effects of once-daily intake of RS on postprandial hypertriglyceridemia remain poorly characterized. In this study, the effects of a single administration of cornstarch-derived RS on postprandial increases in blood triglyceride levels were investigated in rats using oral fat tolerance/loading tests. Following the administration of lipid meals, increases in serum triglycerides levels were significantly reduced in rats fed corn oil containing 500 mg/mL RS. Moreover, fecal lipid volumes and wet weights following lipid meals were significantly greater in rats fed corn oil containing 500 mg/mL RS than in the corn oil only group, confirming the inhibition of dietary fat absorption. Finally, a significant positive correlation was observed between fecal lipid contents and wet weights in rats administered RS. These results suggest that RS intake with dietary fats induces defecation and confirm results of recent reports on the health-promoting potential of once-daily RS intake. (C) 2016 Elsevier Ltd. All rights reserved.

The distribution and characterization of bacteria including lactic acid bacteria (LAB) in the traditional and popular salted fish yegyo ngapi in Myanmar were studied to clarify the contribution of these bacteria to the curing and ripening of this product. Samples of yegyo ngapi purchased from a market in Yangon were used. Most of the isolates obtained using de Man, Rogosa and Sharpe medium containing 10 % NaCl were identified as coccoid LAB on the basis of their basic phenotypic characteristics. From the results of 16S rRNA gene sequencing and PCR-restriction fragment length polymorphism analysis of this gene, most of the isolates were identified as the halophilic LAB Tetragenococcus muriaticus. Analyses of the 16S rRNA gene based on the clone library using DNA extracted from salted fish products were also performed. The results of these molecular-analysis-based techniques showed that spore-forming and non-spore-forming anaerobic bacteria including the genera Clostridium and Halanaerobium in addition to T. muriaticus were also frequently found in bacterial communities. These findings suggest that the anaerobic condition during curing and ripening resulted in bacterial communities composed of strictly anaerobic bacteria and halophilic LAB, and that these bacteria might also contribute to the manufacturing processes of this product. In addition, DNA sequences similar to that of Clostridium botulinum were found in the clone library analysis. Therefore, despite no reports of botulism poisoning from the region where the samples were taken, closer surveillance should be carried out from the viewpoint of food safety.

In insects, trehalose serves as the main sugar component of haemolymph. Trehalose is also recognized as a mediator of desiccation survival due to its proposed ability to stabilize membranes and proteins. Although the physiological role of trehalose in insects has been documented for decades, genetic evidence to support the importance of trehalose metabolism remains incomplete. We here show on the basis of genetic and biochemical evidence that the trehalose synthesis enzyme Tps1 is solely responsible for the de novo synthesis of trehalose in Drosophila. Conversely, a lack of the gene for the trehalose hydrolyzing enzyme Treh causes an accumulation of trehalose that is lethal during the pupal period, as is observed with Tps1 mutants. Lack of either Tps1 or Treh results in a significant reduction in circulating glucose, suggesting that the maintenance of glucose levels requires a continuous turnover of trehalose. Furthermore, changes in trehalose levels are positively correlated with the haemolymph water volume. In addition, both Tps1 and Treh mutant larvae exhibit a high lethality after desiccation stress. These results demonstrate that the regulation of trehalose metabolism is essential for normal development, body water homeostasis, and desiccation tolerance in Drosophila.

Living organisms adapt to environmental changes through metabolic homeostasis. Sugars are used primarily for the metabolic production of ATP energy and carbon sources. Trehalose is a nonreducing disaccharide that is present in many organisms. In insects, the principal hemolymph sugar is trehalose instead of glucose. As in mammals, hemolymph sugar levels in Drosophila are regulated by the action of endocrine hormones. Therefore, the mobilization of trehalose to glucose is thought to be critical for metabolic homeostasis. However, the physiological role of trehalose as a hemolymph sugar during insect development remains largely unclear. Here, we demonstrate that mutants of the trehalose-synthesizing enzyme Tps1 failed to produce trehalose as expected but survived into the late pupal period and died before eclosion. Larvae without trehalose grew normally, with a slight reduction in body size, under normal food conditions. However, these larvae were extremely sensitive to starvation, possibly due to a local defect in the central nervous system. Furthermore, Tps1 mutant larvae failed to grow on a low-sugar diet and exhibited severe growth defects on a low-protein diet. These diet-dependent phenotypes of Tps1 mutants demonstrate the critical role of trehalose during development in Drosophila and reveal how animals adapt to changes in nutrient availability.