Effect of α-casein on DNA adsorption by Andosols and by soil components

Andosols and the soil components (allophanes, humic acids, and goethite) had been autoclaved to destroy the nuclease activity of soil microflora. DNA adsorption by allophanes and Andosols was decreased by increasing the amount of α-casein added to the allophanes and to soils up to casein concentration of 5 mg ml^?1. DNA adsorption by humic acids was significantly increased by increasing the amount of α-casein up to 1.0 mg ml^?1, whereas the addition of 20 mg α-casein ml^?1 completely blocked DNA adsorption. These results can explain why the addition of excess skim milk is operationally needed for effective DNA extraction from Andosols. The amount of DNA adsorbed by Andosols treated with dephosphorylated α-casein was significantly higher than that of not treated Andosols (p?相似文献   

Rice yield losses by competition with weeds in rainfed paddy fields in north-east Thailand

Economic growth in recent years has induced a labor shortage for agriculture in north-east Thailand. Labor-saving techniques, such as the replacement of transplanting with direct seeding, have become widespread. Direct seeding methods have advantages over transplanting regarding labor savings and reductions in production risks, but may cause weed problems. Therefore, rice yield reduction by competition with weeds becomes a potential problem in this region. In the present research, the extent of weed competition in rice production from the viewpoint of resource level and disturbance intensity was studied. A large number of paddy fields from a wide range of climatic, topographical, soil and hydrological conditions were analyzed. The survey was conducted every 3 weeks, and data on paddy cultivation, weeds and water conditions were recorded. Average yield of direct seeded rice was significantly lower than that of transplanted rice. The yield decreased with resource decreases in both direct seeded (DSF) and transplanted paddy fields (TF). Although the yield was not different under resource-rich conditions, the yield of direct seeded rice was lower than that of transplanted rice under resource-medium and -poor conditions. Competition intensity was not different among resource levels or between DSF and TF. Competition intensity in all fields was between 0.02 and 0.09 on average, indicating 2–9% yield losses caused by competition with weeds regardless of resource level and disturbance intensity. This suggests that low yield of direct seeded rice under resource-medium and -poor conditions was not mainly caused by competition with weeds, whereas yield losses by weeds were observed in all field types. However, from an economical viewpoint, weeding should be applied only to limited parts of this region with stable and relatively high rice yields.     

Visualization of <Emphasis Type="Italic">Ralstonia solanacearum</Emphasis> cells during biocontrol of bacterial wilt disease in tomato with <Emphasis Type="Italic">Pythium oligandrum</Emphasis>

The biocontrol agent Pythium oligandrum (PO) can suppress bacterial wilt caused by Ralstonia solanacearum (RS) in tomato. To understand the primary biocontrol mechanisms of bacterial wilt by PO, we pretreated tomato plants with sterile distilled water or preinoculated them with PO, followed by inoculation with RS, then observed PO and RS in fixed sections of tomato tissues using a confocal laser-scanning microscope and fluorescence labeling until 14 days after the inoculation with RS. Horizontal and vertical movement of RS bacteria was frequently observed in the xylem vessels of roots and stems of tomato plants (cv. Micro-Tom) that had not been inoculated with PO. In plants that were preinoculated with PO, the movement of RS was suppressed, and bacteria appeared to be restricted to the pit of vessels, a reaction similar to that observed in resistant rootstocks. PO colonization was mainly observed at the surfaces of taproots, the junctions between taproots and lateral roots, and the middle sections of the lateral roots. PO was not observed near wound sites or root tips where RS tended to colonize. However, RS colonization was significantly repressed at these sites in PO preinoculated plants. These observations suggest that the induction of plant defense reactions is the main mechanism for the control of tomato bacterial wilt by PO, not direct competition for infection sites.     

Antiatherogenic effect of isoflavones in ovariectomized apolipoprotein e-deficient mice

The consumption of isoflavone-containing foods such as soybean and soybean products has been reported to have beneficial effects on the cardiovascular system in postmenopausal women. The present study was carried out to examine the mechanism underlying the beneficial effects of isoflavones in apolipoprotein (apo) E-deficient mice subjected to ovarian resection. Compared with sham-operated mice, ovariectomized mice had a larger arterial lesion area in the aortic root. Feeding the ovariectomized mice an isoflavone-containing diet (0.055 mg/kJ of total isoflavones/cal of diet) reduced the size of these lesions more than did feeding them with an isoflavone-free diet. Neither ovariectomy nor diet had a significant effect on the concentration of cholesterol in serum and urinary levels of isoprostanes, which are biomarkers for oxidative stress in vivo. The ovariectomized mice showed a greater increase in mRNA abundance for monocyte chemoattractant protein (MCP)-I in the aorta and in the level of nitric oxide (NO) secreted by peritoneal macrophages in culture than did the sham-operated mice. The isoflavone-containing diet lowered the MCP-I expression and the NO secretion more than did the isoflavone-free diet. These results suggest that dietary isoflavones confer an antiatherogenic effect by preventing the activation of macrophages due to the removal of ovaries.     

Ingested delphinidin-3-rutinoside is primarily excreted to urine as the intact form and to bile as the methylated form in rats

Many reports have described the bioavailability of anthocyanins; however, most of these reports investigated only the amount of anthocyanins excreted in urine. In the present study, we calculated the pharmacokinetic bioavailability of anthocyanins in rats by measuring the plasma concentration of delphinidin-3-rutinoside that had been administered orally or intravenously. Delphinidin-3-rutinoside was primarily absorbed in the blood and excreted into urine as unmetabolized forms with a T(max) of 26.3 min and a C(max) of 0.285 +/- 0.071 micromol/L. We detected small amounts of the metabolite 4'-O-methyl-delphinidin-3-rutinoside in the plasma, but we detected neither anthocyanidin (aglycone) nor glucuro- or sulfoconjugates. For the 8 h period after intake, delphinidin-3-rutinoside and 4'-O-methyl-delphinidin-3-rutinoside were excreted to urine at 795 +/- 375 and 12.3 +/- 2.91 nmol, respectively. Relative to intravenous injection, oral administration of delphinidin-3-rutinoside resulted in complete bioavailability (0.49 +/- 0.06%). Analysis of delphinidin-3-rutinoside plasma concentrations in bile cannulated rats revealed that, for the 8-h period after intake, the intact delphinidin-3-rutinoside excretion ratio in bile was 11% of the excretion ratio of 4'-O-methyl-delphinidin-3-rutinoside, 1.91 +/- 0.35 nmol versus 17.4 +/- 8.67 nmol, respectively. Setting the bile duct cannulation in a Bollman-type cage, however, significantly increased the bioavailability of orally administered delphinidin-3-rutinoside (18.14 +/- 6.24%). This effect appears to stem immobilization stress by reducing gastrointestinal motility. The cumulative excretion of delphinidin-3-rutinoside and 4'-O-methyl-delphinidin-3-rutinoside in urine and bile was 2.67 +/- 1.24% (w/w) of the dose ingested. Studies report that several metabolites are formed after oral ingestion of anthocyanins. Examples include glucuronyl from cyanidin-3-glucoside and both glucuronyl and sulfate conjugates from pelargonidin-3-glucoside. Our results indicate that delphinidin-3-rutinoside might be metabolized differently from cyanidin-3-glucoside and pelargonidin-3-glucoside.     

Protective effect of supplementation of fish oil with high n-3 polyunsaturated fatty acids against oxidative stress-induced DNA damage of rat liver in vivo

The present study was undertaken to know the effect of supplementation of fish oil with high n-3 polyunsaturated fatty acids (PUFA) on oxidative stress-induced DNA damage of rat liver in vivo. Male Wistar rats were fed a diet containing fish oil or safflower oil with high n-6 PUFA at 50 g/kg of diet and an equal amount of vitamin E at 59 mg/kg of diet for 6 weeks. Livers of rats fed fish oil were rich in n-3 PUFA, whereas those of rats fed safflower oil were rich in n-6 PUFA. Ferric nitrilotriacetate was intraperitoneally injected to induce oxidative stress. The degree of lipid peroxidation of the liver was assessed by the levels of phospholipid hydroperoxides and thiobarbituric acid-reactive substances (TBARS), and the degree of oxidative DNA damage was assessed by comet type characterization in alkaline single-cell gel electrophoresis and 8-hydroxy-2'-deoxyguanosine levels. The levels of TBARS of the livers of the fish oil diet group increased to a greater extent than those of the safflower oil diet group, whereas the levels of the hydroperoxides of the livers of both diet groups increased to a similar extent. The vitamin E level of livers of the fish oil diet group was remarkably decreased. The degree of DNA damage of both diet groups was increased, but the increased level of the fish oil diet group was remarkably lower than that of the safflower oil diet group. The above results indicate that fish oil supplementation does not enhance but appears to protect against oxidative stress-induced DNA damage and suggest that lipid peroxidation does not enhance but lowers the DNA damage.     

Conversion of dextran to cycloisomaltooligosaccharides using an enzyme-immobilized porous hollow-fiber membrane

This paper describes a cycloisomaltooligosaccharide glucanotransferase (CITase)-multilayer-immobilized porous hollow-fiber membrane used as an enzyme bioreactor. Dextran, a substrate with an average molecular mass of 43000, is converted into seven- to nine-glucose-membered cycloisomaltooligosaccharides, effective as a preventive for dental caries, aided by convective transport of the substrate to the vicinity of the enzyme through the pores. Epoxy-group-containing graft chains were uniformly appended onto the surface of pores throughout a porous hollow-fiber membrane by radiation-induced graft polymerization. Subsequently, a diethylamino group was introduced, as an anion-exchange moiety, to the graft chains, which caused the chains to expand toward the interior of the pores due to mutual electrostatic repulsion. The expanding graft chain provided multilayer binding sites for CITase. Fifty-five milligrams of adsorbed CITase per gram of membrane is equivalent to the degree of multilayer binding of 5. Finally, 80% of the multilayer-adsorbed CITase was immobilized via enzymatic cross-linking with transglutaminase to prevent the leakage of enzymes. CITase, with a degree of multilayer immobilization of 4, produced the target cycloisomaltooligosaccharides at a conversion yield of 55% in weight at 310 K during permeation by the dextran solution at a space velocity defined as the permeation rate divided by membrane volume of 6 per hour.     

Vitelline cyst in the rat ileum

Congenital vitelline duct anomalies other than Meckel’s diverticulum are rare in animals. A cyst of approximately 8 mm in diameter was observed on the antimesenteric surface of the ileal serosa in a 10-week-old female Crl:CD(SD) rat. Microscopically, the cyst closely resembled the ileum, but it did not communicate with the ileal lumen. We diagnosed this case as a vitelline cyst derived from the vitelline duct based on the location where it developed and its histological behavior. In rats, only Meckel’s diverticulum has been reported with a congenital anomaly of the vitelline duct, and no other spontaneous anomalies including a vitelline cyst have been reported. This case may be the first report concerning a vitelline cyst in the rat ileum.