[Association between development of hypertension and nutrition in school-age children in Fengdu County of Chongqing, China].

OBJECTIVE: To investigate the association between the development of hypertension and nutrition in school-age children in Fengdu County of Chongqing, China. METHODS: A total of 8 033 children from 2 public primary schools in Fengdu County of Chongqing, whose registered residence was in the subdistricts where the two schools were located, were selected as study subjects using cluster random sampling. Body height, body weight, and blood pressure were measured, and the semi-quantitative food frequency questionnaire was used for dietary survey. The association between body mass index (BMI), dietary nutrients, and the development of hypertension in children was analyzed. RESULTS: A total of 7 538 children were enrolled for analysis. The detection rates of obesity, overweight, and hypertension were 9.11%, 12.27%, and 11.83% respectively. In children with obesity and overweight, the detection rate of hypertension was 33.62% and 17.84% respectively, 4.02 and 2.13 times that in normal children. The multivariate logistic stepwise regression analysis revealed that increased intake of calcium and sodium increased the risk of hypertension (OR=1.003 and 1.002 respectively), while the increased iron intake and calcium intake per unit body weight reduced the risk of hypertension (OR=0.979 and 0.926 respectively). CONCLUSIONS: The prevalence of hypertension and obesity in school-age children in Fengdu County of Chongqing is high. BMI and dietary nutrients are closely associated with the development of hypertension in children. Active control of body weight, adjustment of dietary structure, and limitation of sodium intake should be adopted to reduce the development of hypertension in school-age children.

Cellulase hydrolysis of rice straw and inactivation of endoglucanase in urea solution.

In order to optimize the cellulase (from Aspergillus glaucus) hydrolysis of pretreated rice straw, the effects of varying enzyme concentration, temperature, and pH were studied. The best experimental conditions found to degrade the pretreated rice straws were 24 h of incubation at 55 °C and pH 5.0, with an enzyme concentration of 48 mg/L. Urea is one of the important nitrogen sources used in fungi culture, but it is also a denaturant. The model of denaturation of endoglucanase (EG) in urea solutions was established. The denaturation was a slow, reversible reaction. Determination of microscopic rate constants showed k(+0) > k'(+0), indicating that EG was protected by the substrate to a certain extent during denaturation. Comparison with the results from fluorescence emission spectroscopy revealed that the inactivation of EG occurred before the marked conformational changes could be detected.

Purification and properties of endoglucanase from a sugar cane bagasse hydrolyzing strain, Aspergillus glaucus XC9.

An endoglucanase (EG) from Aspergillus glaucus XC9 grown on 0.3% sugar cane bagasse as a carbon source was purified from the culture filtrate using ammonium sulfate, an anion exchange DEAE Sepharose fast flow column, and a Sephadex G-100 column, with a purification fold of 21.5 and a recovery of 22.3%. The ideal time for EG production is on the fourth day at 30 degrees C using bagasse as a substrate. Results obtained indicate that the enzyme was a monomer protein, and the molecular weight was determined to be 31 kDa. The optimum pH and temperature of EG for the hydrolysis of carboxymethylcellulose sodium (CMC-Na) were pH 4.0 and 50 degrees C, respectively. EG was stable over the pH range from 3.5 to 7.5 and at temperatures below 55 degrees C. Kinetic behavior of EG in the hydrolysis of CMC-Na followed Michaelis-Menten kinetics with constant K(m) of 5.0 mg/mL at pH 4.0 and 50 degrees C. The enzyme activity was stimulated by Fe(2+) and Mn(2+) but inhibited by Cd(2+), Pb(2+), and Cu(2+). The EDC chemical modification suggested that at least one carboxyl group probably acted as a proton donor in the enzyme active site.

[Inhibition of postharvest decay and induction of defensive enzymes by pure oxygen in Chinese bayberry fruit].

Chinese bayberry fruits were stored in air (control) or pure oxygen atmosphere for up to 12 days at 5 degrees C to investigate the effects of high oxygen on decay control and its relation to the induction of defensive enzyme activities. The results showed that exposure of Chinese bayberry to pure oxygen significantly prevented fruit decay. At the end of the storage period, the decay index of fruits exposed to pure oxygen was only 17% while that of control fruits reached 54% (Fig.1). Pure oxygen caused a significant increase in chitinase and beta-1,3-glucanase activities which reached a peak on the 6th day of storage (Fig.2). Phenylalanine ammonium-lyase (Fig.3A) and peroxidase (Fig.4) activities as well as total phenolic content (Fig.3B) increased more quickly and stayed at significantly higher levels in fruits exposed to pure oxygen during storage than the control fruits. These results suggest that the inhibition of postharvest fruit decay by high oxygen was related to the induction of defensive enzyme activities. The induced disease resistance may be involved in the mechanisms by which high oxygen treatment inhibited fruit decay in Chinese bayberry.