ve To establish a method of high performance liquid chromatography (HPLC) for determi-nation of nitrite in water. Methods The trace content of nitrite in water sample was determined by indirect UV-HPLC. The mixture of methanol/o-phthalic acid (pH value was adjusted to 8.6 by 0.10 mol/L NaOH solution)5: 95 was defined as mobile phase. The water sample was directly filtered by chromatographic column pack with ODP. Results Under the conditions of wave length of 270 nm and flow rate of 0.9 ml/ min, the linear range of this assay was 0.0~20.0?g/ml nitrite, the relative standard deviation was 3.9%. The average recovery rate and detection limit were 99.9% and 0.001?g/ ml respectively. Conclusion This method could be applied to the determination of trace amount of nitrite in drinking water, purified water and mineral water.

Auxotrophic strains of N1-37 (Phe-) and N2-27 (His-), screened from mutations of Paenibacillus polymyxa JSa-9 previously, were used as the parent strains to screen high-producing LI-F antibacterial lipopeptide fusion strain through protoplast fusion with polyethylene glycol as a promote agent. Fusion strain F5-15 was obtained. Then the product of LI-F antibacterial lipopeptide was quantified by HPLC, and the difference of expression of the key genes of lipopeptide synthase between wild strain JSa-9 and the fusion strain was analyzed by real-time PCR. LI-F antibacterial lipopeptide yield of the fusion strain F5-15 was 3.1-fold of the original strain JSa9's, and the expression levels of the target genes were 10.48, 2.48, 2.1 and 11.8 fold of the initial strain JSa-9, respectively.
Anti-Bacterial Agents ; biosynthesis ; Chromatography, High Pressure Liquid ; Lipopeptides ; biosynthesis ; Paenibacillus ; metabolism ; Protoplasts ; metabolism ; Real-Time Polymerase Chain Reaction

Objective:To investigate the normal range of exhaled nitric oxide in healthy children aged 6-18 in Jinan.Methods:The healthy school children aged 6-18 in Jinan from October 11 to 26, 2017 were selected for questionnaire survey, physical examination and exhaled nitric oxide test.The levels of mouth exhaled nitric oxide at the flow rate of 50 mL/s (FeNO 50) and mouth exhaled nitric oxide at the flow rate of 200 mL/s(FeNO 200), alveolar nitric oxide (CaNO), and nasal exhaled nitric oxide at the flow rate of 10 mL/s(FnNO 10) were measured by the electroche-mical method.The distributions of FeNO 50, FeNO 200, CaNO and FnNO 10 were analyzed, and their correlations with gender, age, height and body mass index (BMI) were discussed by the multiple linear regression model. Results:A total of 772 healthy children were enrolled in this study, including 364 males and 408 females, with a median age of 12.1(11.8-12.3) years old, a median height of 154.8(153.6-156.0) cm, and a median BMI of 20.3 (20.0-20.6) kg/m 2. The measured values of FeNO 50, FeNO 200, CaNO and FnNO 10 fluctuated in the range of 3.0-168.0 ppb, 2.0-44.0 ppb, 0.5-44.2 ppb and 0-1 253.0 ppb, respectively.FeNO 50, FeNO 200 and CaNO values showed skewed a distribution, and their 95% upper limits were 35.0 ppb, 13.3 ppb and 8.5 ppb, respectively.The geometric mean(95% CI) of FeNO 50 in males (95% CI)[14.6 (13.7-15.5) ppb] was significantly higher than that in females [13.3(12.7-14.0) ppb], and the difference was statistically significant ( Z=1.470, P=0.027). The multiple linear regression results suggested that, FeNO 50 was positively correlated with age and height ( β=0.023, 0.007, respectively, all P<0.05), and negatively correlated with BMI ( β=-0.016, P<0.05). The geometric mean (95% CI) of FeNO 200in males[7.1 (6.8-7.4) ppb] was significantly higher than that in females[6.4 (6.1-6.6) ppb], and the difference was statistically significant( Z=1.747, P=0.004). The multiple linear regression results suggested that, FeNO 200 was positively correlated with height ( β=0.005) and negatively correlated with gender(female β=-1.126) (all P<0.05). There was no significant difference between male and female in CaNO, which had no correlation with gender, age, height and BMI (all P>0.05). FnNO 10 showed a normal distribution, with a mean value of 456.2 ppb, 95% CI of 29.3-863.4 ppb.The geometric mean (95% CI) of FnNO 10 in males [408.7 (377.1-443.0) ppb] was significantly higher than that in females [368.8 (339.0-401.3) ppb], and the difference was statistically significant ( Z=1.722, P=0.005). The multiple linear regression results indicated that FnNO 10 was related to gender ( β=-36.098, P<0.05), and not correlated with age, height and BMI (all P>0.05). Conclusions:The normal ranges of FeNO 50, FeNO 200, CaNO and FnNO 10 in healthy children aged 6-18 in Jinan are 3.0-35.0 ppb, 2.0-13.3 ppb, 0.5~8.5 ppb and 29.3-863.4 ppb, respectively.FeNO 50 is correlated with age, height and BMI.FeNO 200 is correlated with gender and height.CaNO and FnNO 10 are not correlated with age, height or BMI.

The tea beverages will be endowed with distinct aroma and taste, as well as various biologically active compounds including probiotic factors, when fermented with lactic acid bacteria (LAB). However, at present, few studies on the dynamics of flavors in tea soup at different fermentation stages were conducted. In this study, the composition of monosaccharides, aromatic components, free amino acids, and organic acids were measured, when the black tea beverages were fermented with Lactobacillus coryniformis FZU63 which was isolated from Chinese traditional kimchi. The results indicated that monosaccharides including glucose, fructose, mannose and xylose in black tea beverages are the main carbon sources for fermentation. In addition, the abundance of aromatic compounds in black tea soup are increased significantly at different fermentation stages, which endow the fermented black tea soup with fruit aroma on the basis of flowery and nutty aroma. Moreover, some bitter amino acids are reduced, whereas the content of sweet and tasty amino acids is elevated. Furthermore, the levels of lactic acid, malic acid, citric acid and other organic acids are accumulated during the fermentation. Additionally, sensory evaluation displays that black tea beverage is acquired with comprehensive high-quality after being fermented for 48 h. This study provides a theoretical basis to steer and control the flavor formation and quality of the fermented tea beverages during LAB fermentation.
Tea/chemistry* ; Beverages/microbiology* ; Camellia sinensis ; Fermentation ; Acids ; Amino Acids ; Glucose