Manipulation of the rice L-galactose pathway: evaluation of the effects of transgene overexpression on ascorbate accumulation and abiotic stress tolerance.

Ascorbic acid (AsA) is the most abundant water-soluble antioxidant in plants, and it plays a crucial role in plant growth, development and abiotic stress tolerance. In the present study, six key Arabidopsis or rapeseed genes involved in AsA biosynthesis were constitutively overexpressed in an elite Japonica rice cultivar. These genes encoded the GDP-mannose pyrophosphorylase (GMP), GDP-mannose-3',5'-epimerase (GME), GDP-L-galactose phosphorylase (GGP), L-galactose-1-phosphate phosphatase (GPP), L-galactose dehydrogenase (GDH), and L-galactono-1,4-lactone dehydrogenase (GalLDH). The effects of transgene expression on rice leaf AsA accumulation were carefully evaluated. In homozygous transgenic seedlings, AtGGP transgenic lines had the highest AsA contents (2.55-fold greater than the empty vector transgenic control), followed by the AtGME and AtGDH transgenic lines. Moreover, with the exception of the AtGPP lines, the increased AsA content also provoked an increase in the redox state (AsA/DHA ratio). To evaluate salt tolerance, AtGGP and AtGME transgenic seedlings were exposed to salt stress for one week. The relative plant height, root length and fresh weight growth rates were significantly higher for the transgenic lines compared with the control plants. Altogether, our results suggest that GGP may be a key rate-limiting step in rice AsA biosynthesis, and the plants with elevated AsA contents demonstrated enhanced tolerance for salt stress.

A dose-response meta-analysis of dietary lutein and zeaxanthin intake in relation to risk of age-related cataract.

BACKGROUND: Lutein and zeaxanthin are thought to have beneficial effects on protecting the lens against cataract formation, but findings from epidemiologic studies have been inconsistent. We aimed to conduct a meta-analysis of prospective cohort studies to examine the association between dietary lutein and zeaxanthin intake and risk of age-related cataract (ARC). METHODS: We systematically searched MEDLINE, EMBASE, Web of Science, and Cochrane Library databases up to March 2013. Reference lists from retrieved articles were also reviewed. The adjusted relative risks (RRs) from each study were extracted to calculate a pooled estimate with its 95 % confidence interval (CI). The dose-response relationships were assessed by using generalized least-squares trend estimation. RESULTS: Six prospective cohort studies were identified involving 4,416 cases and 41,999 participants. For the comparison between the highest and the lowest categories of dietary lutein and zeaxanthin intake, significant inverse association were found for nuclear cataract (RR: 0.75; 95 % CI: 0.65, 0.85), but not for cortical cataract (RR: 0.85; 95 % CI: 0.53, 1.17) and for posterior subcapsular cataract (RR: 0.77; 95 % CI: 0.40, 1.13). Dose-response analysis showed that every 300 µg/d increment in dietary lutein and zeaxanthin intake was associated with a 3 %, 1 %, or 3 % reduction in the risk of nuclear cataract (RR: 0.97; 95 % CI: 0.94, 0.99), cortical cataract (RR: 0.99; 95 % CI: 0.95, 1.02), or posterior subcapsular cataract (RR: 0.97; 95 % CI: 0.93, 1.01) respectively. CONCLUSIONS: Dietary lutein and zeaxanthin intake is associated with a reduced risk of ARC, especially nuclear cataract in a dose-response manner, indicating a beneficial effect of lutein and zeaxanthin in ARC prevention.

Prevalence of asthenopia and its risk factors in Chinese college students.

AIM: To determine the prevalence of asthenopia and identify any associated risk factors in the college students in Xi'an, China. METHODS: From April to September 2012, 1 500 students from five universities in Xi'an were selected according to a multi-stage stratified cluster sampling method. Data on demographic features, lifestyle or dietary habits, health status, living environment conditions, sleep and mental status, and asthenopia symptoms were collected through a self-administered validated questionnaire. Univariate logistic regression and multivariate logistic regression analysis modified by the factor analysis were performed to evaluate risk factors for asthenopia. RESULTS: Fifty-seven percent of the college students complained of asthenopia. Statistically significant risk factors for asthenopia in the univariate analysis included 13 variables. Multivariate analysis revealed a significant relationship between the use of computer and asthenopia (OR 1.21, 95%CI: 1.09 to 1.35). Good sleep and mental status (OR 0.86, 95%CI: 0.76 to 0.97), good living environment conditions (OR 0.67, 95%CI: 0.60 to 0.76), and high intake of green leafy vegetables (OR 0.89, 95%CI: 0.80 to 0.98) were found to be strong predictors of decreasing the occurrence of asthenopia complaints. CONCLUSION: Asthenopia symptom appears to be common among college students; and it is strongly associated with computer use, psychosocial state, environment conditions and dietary habits, suggesting that additional studies are warranted to verify these risk factors and establish prevention guidelines, especially for college students.

[Fertility rate and the prediction of future population size in Shaanxi province].

OBJECTIVE: To analyze the fertility rate and to estimate the future population size of Shaanxi province, based on data from the sixth national population census. METHODS: Fertility rate curve was used to analyze the fertility model and the abbreviated life table. The actual fertility rate was used as the main way to predict the future population size. General fertility rate was analyzed by factor analysis approach. RESULTS: The total fertility rate of Shaanxi province was 1.05 in 2010 while age-specific fertility rate contributed 101.27% to the general fertility rate. The expected population sizes would be 38 122 474 in 2015, 38 432 931 in 2020 and 38 121 904 in 2025 respectively. CONCLUSION: Birthrate would become lower and the population size appearing a negative increase in the year 2020, in Shaanxi province.

[Study on the diet quality and its relative effect factors among rural residents, using the Chinese Diet Balance Index (CDBI) in Hanzhong, Shaanxi province].

OBJECTIVE: To evaluate the diet quality and the relative factors among rural residents in Hanzhong, Shaanxi province. METHODS: A cross-sectional survey on dietary status together with a semi-quantitative food frequency questionnaire were conducted on rural residents aged from 18 to 80 in Hanzhong of Shaanxi in 2010. Diet quality was evaluated by using the Chinese Diet Balance Index (CDBI) scoring and evaluating system. Linear regression models were developed to identify factors that influencing the status of under/over intake. RESULTS: 2748 rural residents were investigated with the average daily intake of grains, beans, heavily salted vegetables, plant oil, nuts and salt. Results showed that they were higher than average level of Chinese rural residents' (P < 0.01). 80% of the residents having their daily intake of grains, oil and salt exceeded, while animal food, diary food, egg, vegetable and fruits were lower (P < 0.01) than the RNIs. However, there was under intake noticed to some extent in some areas. The average values of DBI_LBS and DBI_HBS were 22.8 and 9.8. The proportions of moderate under intake (20 < DBI_LBS ≤ 40) and moderate over intake (10 < DBI_HBS ≤ 20) were 62.6% and 48.0%. The main factors that influenced the dietary under-intake were education level, fortune index, hypertension, physical activity, and time to watch television. The main factors that affected the over-intake of diet were sex, age, number of family numbers, intensity of labor, time to sleep, smoking and drinking habits. CONCLUSION: The main diet problem among the rural residents was under-dietary-intake, with over-intake to some extents, suggesting that it was necessary to strength the specific intervention program, to improve the diet quality in the residents of Hanzhong area.

Lutein supplementation reduces plasma lipid peroxidation and C-reactive protein in healthy nonsmokers.

OBJECTIVE: The aim of this study was to determine whether lutein affected biomarkers related to cardiovascular diseases (CVD) in healthy nonsmokers. METHODS: A randomized, double-blind, placebo-controlled trial of lutein supplementation was conducted in healthy nonsmokers. 117 eligible subjects were randomly assigned to receive 10 or 20 mg/d of lutein or placebo for 12 weeks. Levels of plasma carotenoid concentrations, total antioxidant capacity (TAOC), the lipoprotein profile, and antioxidant enzymes activities were determined at baseline and at 6, and 12 weeks after the initiation of treatment. Biomarkers of oxidative damage to protein and lipids, and C-reactive protein (CRP) concentrations were measured at baseline and after supplementation. RESULTS: Plasma lutein and TAOC significantly increased in both active treatment groups during 12 weeks. A significant reduction was found in malondialdehyde in the 20 mg lutein group. CRP concentration decreased in a dose-dependent manner for lutein supplementation, and there was a significant between-group difference in CRP between the 20 mg lutein and the placebo group. Serum CRP was directly related to the change in plasma lutein and TAOC for both active treatment groups. CONCLUSION: The results support the possibility that lutein supplementation reduce biomarkers of CVD risk via decreased lipid peroxidation and inflammatory response by increasing plasma lutein concentrations and antioxidant capacity.

Increased α-tocotrienol content in seeds of transgenic rice overexpressing Arabidopsis γ-tocopherol methyltransferase.

Vitamin E comprises a group of eight lipid soluble antioxidant compounds that are an essential part of the human diet. The α-isomers of both tocopherol and tocotrienol are generally considered to have the highest antioxidant activities. γ-tocopherol methyltransferase (γ-TMT) catalyzes the final step in vitamin E biosynthesis, the methylation of γ- and δ-isomers to α- and ß-isomers. In present study, the Arabidopsis γ-TMT (AtTMT) cDNA was overexpressed constitutively or in the endosperm of the elite japonica rice cultivar Wuyujing 3 (WY3) by Agrobacterium-mediated transformation. HPLC analysis showed that, in brown rice of the wild type or transgenic controls with empty vector, the α-/γ-tocotrienol ratio was only 0.7, much lower than that for tocopherol (~19.0). In transgenic rice overexpressing AtTMT driven by the constitutive Ubi promoter, most of the γ-isomers were converted to α-isomers, especially the γ- and δ-tocotrienol levels were dramatically decreased. As a result, the α-tocotrienol content was greatly increased in the transgenic seeds. Similarly, over-expression of AtTMT in the endosperm also resulted in an increase in the α-tocotrienol content. The results showed that the α-/γ-tocopherol ratio also increased in the transgenic seeds, but there was no significant effect on α-tocopherol level, which may reflect the fact that γ-tocopherol is present in very small amounts in wild type rice seeds. AtTMT overexpression had no effect on the absolute total content of either tocopherols or tocotrienols. Taken together, these results are the first demonstration that the overexpression of a foreign γ-TMT significantly shift the tocotrienol synthesis in rice, which is one of the world's most important food crops.

[Dietary patterns and its relationship with hypertension among rural residents in Hanzhong, Shanxi province].

OBJECTIVE: To investigate the relationship between dietary patterns and hypertension in Hanzhong city of Shanxi province. METHODS: A cross-sectional survey on dietary pattern and hypertension together with a semi-quantitative food frequency questionnaire was conducted among rural residents aged from 18 to 80 in Hanzhong of Shanxi province in 2010. Factor analysis by SPSS was used to identify food patterns based on the frequency of food. Logistic regression was used to analyze the relationship between dietary patterns and hypertension. RESULTS: 2929 rural residents were investigated with an average age as 50.0 years old and average schooling-years as 6.8. The prevalence rate of hypertension was 34.3%, with 35.4% in males and 33.7% in females. Among 29 kinds of food under investigation, only 11 kinds with the frequencies of consumption more than 1 time per week. Four main factors were derived as four dietary patterns by factor analysis and they were diversity dietary pattern, alcohol dietary pattern, beverage dietary pattern and simple dietary pattern. Among them, the balanced dietary pattern was significantly associated with hypertension. All the participants were categorized into 4 groups (Q1-Q4) according to their factor scores, quartile with Q1 as a reference. The residents who were more closer to having balance dietary pattern, were under less risk of suffering from hypertension after controlling for age, sex, BMI, education and income. Compared to Q1, the Q4 had lower risk of hypertension (OR = 0.59, 95%CI: 0.44 - 0.77) for the balanced pattern. CONCLUSION: Dietary pattern could be related to the prevalence of hypertension. A rational diet with diversity of foods should be suggested as one of the major measures for the prevention of hypertension.