We have found for the first time that a chromosomal gene, mlr6787, in Mesorhizobium loti encodes the pyridoxine degradative enzyme α-(N-acetylaminomethylene)succinic acid (AAMS) amidohydrolase. The recombinant enzyme expressed in Escherichia coli cells was homogeneously purified and characterized. The enzyme consisted of two subunits each with a molecular mass of 34,000±1,000 Da, and exhibited Km and kcat values of 53.7±6 μM and 307.3±12 min−1, respectively. The enzyme required no cofactor or metal ion. The primary structure of AAMS amidohydrolase was elucidated for the first time here. The primary structure of the enzyme protein showed no significant identity to those of known hydrolase proteins and low homology to those of fluoroacetate dehalogenase (PDB code, 1Y37), haloalkane dehalogenase (1K5P), and aryl esterase (1VA4).
Royal jelly peptides (RJPx) isolated from hydrolysates of water-soluble royal jelly proteins prepared with protease P exhibited significantly stronger hydroxyl radical-scavenging activity (p<0.001), and antioxidant activity against lipid peroxidation (LPO, p<0.001), than did water-soluble royal jelly protein (WSRJP) in vitro. We also investigated the in vivo antioxidant activity of RJPx against ferric nitrilotriacetate (Fe-NTA)-induced LPO. Male Wistar rats were divided into a control group (Group C), an Fe-NTA group (Group Fe), and an Fe-NTA with RJPx group (Group Fe+R). Rats in Group Fe+R were fed RJPx (2 g/kg body weight) daily for 5 wk. Fe-NTA (8 mg Fe/kg body weight) was then intraperitoneally injected, and serum lipid levels were examined 2 h later. Serum total cholesterol (TC) levels were lower (p<0.05) while low-density lipoprotein (LDL) and LPO were significantly higher (p<0.01) in Group Fe than in Group C. TC (p<0.05) and LPO levels (p<0.01) were lower in Group Fe+R than in Group Fe. Our data suggest that RJPx may inhibit LPO both in vitro and in vivo.
Background and aim: We have previously shown that serum plasmalogen levels positively correlate with HDL, and significantly decrease with aging, and may be related to LDL particle size. The objective of the present study was to investigate the effects of increased serum plasmalogens on lipidosis, particularly the appearance of atherogenic small dense LDL (sdLDL), of subjects with hyperlipidemia and metabolic syndrome (MetS). Methods and results: The effects of increased serum plasmalogen levels, induced by 2 wk of myo-inositol treatment, on several clinical and biochemical parameters were examined in 17 hyperlipidemic subjects including some with MetS. After myo-inositol treatment, significant increases in plasmalogen-related parameters, particularly ChoPlas, and significant decreases in atherogenic cholesterols including sdLDL, were observed. Among the hyperlipidemic subjects treated with myo-inositol, compared to subjects without MetS, subjects with MetS had a significant increase in plasmalogens and a tendency towards reduced sdLDL, high sensitivity C-reactive protein (hsCRP), and blood glucose levels. Correlation analyses between the measured parameters showed that plasmalogens, as well as HDL, function as beneficial factors, and that sdLDL is a very important risk factor that shows positive correlations with many other risk factors. Conclusion: These results suggest that increased plasmalogen biosynthesis and/or serum levels are especially effective in improving MetS among hyperlipidemic subjects with MetS.
This study examined whether the chain length of glucose in the diet could affect the selection of foods by Zn-adequate and Zn-deficient rats. Dextrin, maltose and glucose were used as sources of carbohydrate in the diet and the selection patterns of the rats were analyzed for 28 d by a 3-choice selection. Diets provided as a set of three either Zn-adequate or Zn-deficient diets were rotated daily. The Zn-adequate control rats selected widely from the three diets throughout the 28 d. In contrast, rats fed a Zn-deficient diet selected exclusively and continuously the dextrin diet or dextrin and glucose diets from the three diets over the experimental periods. The average daily total food intakes of rats fed a Zn-deficient diet were very significantly decreased. The selections of dextrin, maltose and glucose diets in the 3-choice methods of the control rats were 5.7±1.6b, 5.8±2.0b and 2.7±0.9a g/d, respectively (p<0.05), and those of the Zn-deficient rats were 6.4±2.5c, 0.8±1.3a and 2.6±1.4b g/d, respectively (p<0.05). The ratios of the selected maltose-diet in the Zn-adequate control and the Zn-deficient rats were 40.8±13.8 and 9.0±15.6%, respectively (p<0.01) and those of the dextrin-diet were 40.3±11.4 and 63.0±22.3%, respectively (p<0.05). The decreased preference for the maltose-diet in the Zn-deficient rats may reflect the increased selection of the dextrin-diet.
Effects of dietary unesterified plant sterols and plant sterol oleates and stearates on absorption and metabolism of cholesterol were compared in rats fed a cholesterol-supplemented diet. Fecal excretion of neutral steroids (cholesterol plus coprostanol) in rats fed unesterified plant sterols or plant sterol oleates was significantly higher than in those fed the control diet or plant sterol stearates. Deposition of cholesterol in the liver was significantly lower in rats fed unesterified plant sterols or plant sterol oleates than in those fed the control diet or plant sterol stearates. No significant difference was observed in fecal excretion of cholesterol plus coprostanol and hepatic cholesterol concentration between unesterified plant sterols and plant sterol oleates. Unesterified plant sterols were significantly more effective to reduce lymphatic recovery of radiolabeled cholesterol given to the stomach than plant sterol oleates. Although our observations suggest a possibility that unesterified plant sterols are potentially more effective to inhibit cholesterol absorption than plant sterol oleates in rats, difference in the activity is substantially small between these two forms of plant sterols.
To investigate the effect of dams' dietary fat type during pregnancy and lactation on fat choice of pups, three groups of dams were fed one of three diets: a low fat diet (LFD), a control diet (CTD) or a high fat diet (HFD). After weaning their pups were offered a self-selection regimen of both a fat protein diet (FPD) and a carbohydrate protein diet (CPD) for 3 wk. Although the ratio of FPD intake [FPD intake (g)/total intake (g)] by pups nursed by dams fed LFD during the self-selection period was higher than that by pups nursed by dams fed CTD and HFD, no significant difference in the ratio was observed between pups nursed by dams fed CTD and HFD. It was considered that pups nursed by dams fed CTD and HFD self-selected FPD and CPD in an adequate fat energy ratio (F ratio) compared to that of AIN-93G and AIN-93M. The ratio of FPD intake by pups of these three groups was 16-21% within the first week after weaning. Although pups nursed by dams fed CTD continued to consume the same ratio of FPD during the self-selection period, the ratio of pups nursed by dams fed LFD increased and that of pups nursed by dams fed HFD decreased. These findings indicate that:  pups nursed by dams fed CTD and HFD have the ability to consume FPD and CPD in an adequate F ratio, and  preferential fat intake of pups nursed by dams fed LFD is stronger than that of pups nursed by dams fed CTD and HFD.
Little information is available to estimate water-soluble vitamin intakes from urinary vitamins and their metabolite contents as possible nutritional markers. Determination of the relationships between the oral dose and urinary excretion of water-soluble vitamins in human subjects contributes to finding valid nutrition markers of water-soluble vitamin intakes. Six female Japanese college students were given a standard Japanese diet in the first week, the same diet with a synthesized water-soluble vitamin mixture as a diet with approximately onefold vitamin mixture based on Dietary Reference Intakes (DRIs) for Japanese in the second week, with a threefold vitamin mixture in the third week, and a sixfold mixture in the fourth week. Water-soluble vitamins and their metabolites were measured in the 24-h urine collected each week. All urinary vitamins and their metabolite levels except vitamin B12 increased linearly in a dose-dependent manner, and highly correlated with vitamin intake (r=0.959 for vitamin B1, r=0.927 for vitamin B2, r=0.965 for vitamin B6, r=0.957 for niacin, r=0.934 for pantothenic acid, r=0.907 for folic acid, r=0.962 for biotin, and r=0.952 for vitamin C). These results suggest that measuring urinary water-soluble vitamins and their metabolite levels can be used as good nutritional markers for assessing vitamin intakes.
We previously reported that lipids extracted from salted herring roe product (Kazunoko), which contains large amounts of cholesterol, phosphatidylcholine and n-3 polyunsaturated fatty acids (PUFAs) such as eicosapentaenoic acid (EPA, 20:5n-3) and docosahexaenoic acid (DHA, 22:6n-3), decreased plasma lipid and glucose concentrations in mice. The aim of this study was to evaluate the effects of Kazunoko containing large amounts of protein on lipid and glucose metabolism in mice. Male Crlj:CD-1 (ICR) mice were fed three experimental diets containing lyophilized Kazunoko for 12 wk. The experimental diets were as follows: without Kazunoko (control diet); 1% Kazunoko (1% Kazunoko diet); and 4% Kazunoko (4% Kazunoko diet). Plasma total cholesterol, phospholipid and glucose concentrations tended to be lower in the 1% and 4% Kazunoko diet groups than in the control diet group. There were significant differences in plasma glucose concentration between the control and 4% Kazunoko diet groups (p<0.05). Plasma adiponectin concentrations in mice fed the 4% Kazunoko diet were also significantly higher than in those fed the control diet (p<0.05), but there were no marked differences in plasma insulin concentration among the three dietary groups. Hepatic total cholesterol and phospholipid contents tended to be lower in the 4% Kazunoko diet group than in control diet group. Plasma and hepatic n-3/n-6 ratios in the 1% Kazunoko diet and 4% Kazunoko diet groups were significantly higher when compared with those of the control diet group (p<0.005 and p<0.0005, respectively). These results suggest that ingestion of Kazunoko influences lipid and glucose metabolism in mice fed the Kazunoko diets, as compared with animals fed the control diet.
Restriction of dietary protein is useful for chronic kidney disease (CKD) patients to protect residual renal function. However, the mechanism by which a low protein diet confers a beneficial effect in CKD patients remains unknown. One possibility is that the benefit from a low protein diet is associated with phosphorus restriction. The aim of this study is to compare the effect of protein and phosphorus on the progression of renal insufficiency using irreversible Thy1 rats, which histopathologically resemble IgA nephropathy. Irreversible Thy1 rats were fed six types of isocaloric diets consisting of three levels of protein (16.9, 12.6, and 8.4%) and two levels of phosphorus (0.5 and 0.3%) for 13 wk. Renal function was assessed biochemically and histopathologically. The low phosphorus (0.3%) diets showed protection of residual renal function regardless of dietary protein content in uremic rats. With the normal phosphorus (0.5%) diets, however, only the very low protein (8.4%) diet showed a beneficial effect, indicating that dietary phosphorus is a more important factor that affects the progression of renal insufficiency than dietary protein in this model. Furthermore, the low phosphorus diet also prevented an increase in serum parathyroid hormone, indicating that a low phosphorus diet might have beneficial effects not only for residual renal function but also for renal osteodystrophy, a typical complication of patients with CKD.
Background: Stress reduces physical and mental tolerances (immune potential) of humans and it induces progression of existing illness or causes latent disorders to become active. Thus, the control and suppression of stress plays an important role in the improvement of quality of life and prevention of diseases. Ginseng, oriental bezoar and glycyrrhiza have been used for Kampo (herbal treatment) for thousand years and a number of pharmacological and clinical studies have reported their effects. However, it has not been previously described how the combination of these most commonly used herbs affect mental stress. Objective: This is a randomized, double-blind, placebo-controlled experiment to examine the effectiveness of reducing stress response by taking Kampo. Ten healthy males (mean age 27±1) participated in the study. The effectiveness of stress reduction was assessed by measuring ECG, salivary chromogranin A (CgA), blood glucose, WBC, granulocytes, lymphocytes, NK cell activity, etc. Salivary and blood measurement values of pre- and post-mental arithmetic stress were compared. In addition, ECG measurement values of pre- and mid-mental arithmetic stress were compared. Results: we observed a higher HF power and a lower SNS index, HR, CgA, WBC and granulocytes in the Kampo trial than those in the placebo trial. The HR, HF power and SNS index were changed significantly (p<0.05) and CgA, WBC and granulocytes tended to show some differences between the two trials (p<0.1). However, blood glucose, lymphocytes, and NK cell activity showed no significant differences between the Kampo and placebo trials. Conclusions: The result suggests that the Kampo should be useful in reducing mental stress.
Bioactive compound substances from Grifola frondosa (maitake) inhibited adipocyte differentiation of B2C1 preadipocytes. This compound is not related to MAP kinase (ERK1 and ERK2) cascades or β-catenin, which inhibit the expression of Glut4, PPARγ and C/EBPα. The compound reduced the expression time of C/EBPβ and C/EBPδ. These results suggest that the inhibitory action of these bioactive compounds on adipocyte differentiation is exhibited through preadipocytes. They cannot induce the expression of PPARγ or C/EBPα because of the reduced expression time of C/EBPβ and C/EBPδ.
Phospholipase D from Streptomyces sp. was found to catalyze the transfer reaction of the dipalmitoylphosphatidyl residue from 1,2-dipalmitoyl-3-sn-phosphatidylcholine to thiamin, pantothenic acid, and their derivatives in a biphasic system. The following phosphatidylated compounds were synthesized: 1,2-dipalmitoyl-3-sn-phosphatidylthiamin, 1,2-dipalmitoyl-3-sn-phosphatidylthiamin propyl disulfide, 1,2-dipalmitoyl-3-sn-phosphatidylthiamin tetrahydrofurfuryl disulfide, 1,2-dipalmitoyl-3-sn-phosphatidylpantothenic acid, and 1,2-dipalmitoyl-3-sn-phosphatidyl-pantothenyl ethyl ether.
7,12-Dimethylbenz[a]anthracene (DMBA)-treated hairless mice exposed to UVB radiation were used to examine the effect of graded levels of vitamin B6 [1, 7 or 35 mg pyridoxine (PN) HCl/kg] on skin tumorigenesis for 18 wk. Compared to the 1 mg PN HCl/kg diet, the 35 mg PN HCl/kg diet significantly elevated the incidence and multiplicity of skin tumors, while there was no difference in skin tumorigenesis between the 7 and 35 mg PN HCl/kg diets. Skin levels of oxidative stress markers (lipid peroxides and protein carbonyls) were unaffected by dietary treatment. Compared to the 1 mg PN HCl/kg diet, the 7 and 35 mg PN HCl/kg diets significantly elevated serum pyridoxal 5'-phosphate (PLP) without affecting the skin level of PLP. The results suggest that dietary supplemental vitamin B6 exaggerates UVB-induced skin tumorigenesis in hairless mice without affecting oxidative stress in the skin.
The banaba leaf (Lagerstroemia speciosa L.) has been used in traditional Oriental medicine to treat diabetes in the Philippines. It contains corosolic acid (CA), a compound which has a hypoglycemic effect. We examined the effect of CA on blood glucose levels and the hydrolysis of disaccharides in the small intestine in mice. CA (10 mg/kg body weight) improved hyperglycemia after an oral administration of sucrose, and significantly reduced the hydrolysis of sucrose in the small intestine. These results suggest that the hypoglycemic activity of CA is derived, at least in part, due to the inhibition of the hydrolysis of sucrose.
We previously suggested in the in vitro mouse jejunum that when the primary epithelial barrier on the villi was largely disabled, a secondary mucosal barrier substitutes for the primary one. This study showed that the mucosal Ca2+ removal did not further deteriorate the histology but increased transmural conductance and lucifer yellow flux, and decreased forskolin-induced potential difference. It is suggested that in this injury model the postulated secondary barrier is Ca2+-dependent and likely to be present on or immediately beneath the mucosal surface.