Precolumn derivatization LC-MS/MS method to simultaneous quantitation of 10 monosaccharides in rat plasma.

Monosaccharides are essential for maintaining the normal physiological functions of living organisms. Under disease states, metabolic disorders in vivo will inevitably affect the levels of monosaccharides, which brings the possibility of monosaccharides as a biomarker of some diseases. In this study, a method was developed and validated for simultaneously determining 10 monosaccharides (glucose, galactose, mannose, rhamnose, fucose, xylose, iduronic acid, glucuronic acid, N-acetylgalactosamine and N-acetylglucosamine) in SD rat plasma using liquid chromatography-tandem mass spectrometry. The method employed 1-phenyl-3-methyl-5-pyrazolone (PMP) as a derivatization reagent, considerably improved the chromatographic retention and ionization efficiency of monosaccharides. After protein precipitation of plasma samples, monosaccharides and isotope internal standards were derivatized and liquid-liquid extraction was performed to remove excess PMP. To achieve the baseline separation of several isomers, the resulting derivatives were chromatographed on a Bridged ethyl hybrid (BEH) Phenyl column using gradient elution with a total run time of 8 min. The method was linear within the range of 0.0100-5.00 µg/mL for rhamnose, 0.0500-25.0 µg/mL for fucose, xylose, iduronic acid, glucuronic acid, N-acetylgalactosamine and N-acetylglucosamine, 1.00-500 µg/mL for galactose, 10.0-5000 µg/mL for mannose, and 50.0-25,000 µg/mL for glucose. And the accuracy and precision verification of surrogate matrix samples and plasma samples met the required criteria. The method has been used successfully to study the effect of hepatic insufficiency on monosaccharide levels in rats. It was found that the concentration of glucuronic acid in SD rat plasma was abnormally increased in rats with liver injury.

Influence of cluster thinning and girdling on aroma composition in 'Jumeigui' table grape.

Cluster thinning and girdling are common and simple practices applied to improve berry quality in table grape cultivation. However, there is limited information about the accumulation and biosynthesis of the entire aromatic profile under cluster thinning and girdling, notably in table grapes. This research investigated the influences of cluster thinning and girdling (alone or in combination) on aroma profiles, particularly the changes in biosynthesis and accumulation of Muscat-flavored related compounds from véraison to harvest in 'Jumeigui' grape. Cluster thinning and girdling (alone or in combination) significantly increased the concentrations of total soluble solids (TSS) and key aromatic compounds at harvest, with higher concentrations of both under cluster thinning than girdling. Berry weight and titratable acidity (TA) were unaffected by cluster thinning, girdling, or in combination at harvest. Linalool, the most abundant and active odorant related to Muscat flavor, accumulated in 28.6% and 20.2% higher concentrations from cluster thinning than control and girdling at maturity, respectively. Furthermore, higher DXS3 transcript abundance in cluster thinning groups might contribute to the increased accumulation of terpenes and linalool in 'Jumeigui' grape. The results will contribute to further understand the mechanism of source/sink ratio modulation on aroma accumulation and better apply cluster thinning and girdling for grape production.

Impact of cluster thinning on transcriptional regulation of anthocyanin biosynthesis-related genes in 'Summer Black' grapes.

Cluster thinning is an agronomic practice that strongly affects anthocyanin biosynthesis in the skin of grape berries. However, the impact of cluster thinning on anthocyanin biosynthesis has not been fully elucidated at the molecular level. Here, we investigated its effects on the berry quality, the biosynthesis of anthocyanins, and the expression levels of related genes from the onset of véraison to harvest in 'Summer Black' grapes. It was observed that the total soluble solid and anthocyanin content in berry skin significantly increased under cluster thinning, whereas the berry weight and titratable acidity showed no differences from the beginning of véraison to harvest. The expression level of most anthocyanin biosynthesis-related genes was significantly up-regulated by cluster thinning from the beginning of véraison and was higher at its end compared to the control. Up-regulation of flavonoid 3',5'-hydroxylase (F3'5'H) and O-methyltransferase (OMT) expression, and down-regulation of flavonoid 3'-hydroxylase (F3'H) expression were observed, which might be the cause of shift in the anthocyanin profile. These findings provide insights into the molecular basis of the relationship between cluster thinning and anthocyanin biosynthesis in the grape berry skin.

High Temperature Affects Photosynthetic and Molecular Processes in Field-Cultivated Vitis vinifera L. × Vitis labrusca L.

High-temperature stress markedly influences grape growth and development. However, how high-temperature stress response differs between controlled and field-cultivated grape is poorly understood. In this study, the effects of heat treatment on grapevines were studied for changes in photosystem II (PSII) activity and expression levels of heat-responsive genes and heat shock protein HSP21. July 31st, 2015 was considered as the post high-temperature treatment ("42°C"; temperatures above 40°C for a period of time each day ranging from 1-7 h) under field cultivation in our experiment. The recovery of chlorophyll fluorescence indicators and the increasing expression of heat-responsive genes and the heat shock protein HSP21 suggested the development of heat tolerance in the form of acclimation in grape. Changes in various parameters of photosynthetic pigment fluorescence and of the electron transport chain (Fv/Fm, PIABS , Wk , RCQA , ΦPo , and ΦEo ) between "42°C" and the 45°C treatment demonstrated that the donor side, reaction center, and acceptor side of PSII were influenced by a critical high temperature. Furthermore, the difference between the two cultivation conditions studied was attributed to other environmental factors and inherent tree vigor.

Changes in the protective mechanism of photosystem II and molecular regulation in response to high temperature stress in grapevines.

The response to high temperature stress, which influences the growth and development of grapes, varies between laboratory conditions and ambient growth conditions, and is poorly understood. In the present study, we investigated the effects of high temperature on grapevines (Vitis vinifera L. × Vitis labrusca L.) grown under artificial and ambient conditions. A temperature of 35 °C did not alter Photosystem II (PS II) activity and the expression of some heat-shock protein (HSPs) genes. These changes were, however, observed at 45 °C under artificial conditions, as well as when the ambient natural temperature was greater than 40 °C. Interestingly, these changes corresponded to shifts in PS II activity and HSPs expression. The protective mechanism of PS II was induced by temperatures greater than 40 °C. These data indicating that the expression of HSFA2, GLOS1 and some heat-shock protein (sHSPs) genes were more sensitive to the heat stress. Unlike the Kyoho grapevines, the Jumeigui grapevines showed rapid and dramatically deterioration in PS II activity and the expression of some heat response genes and HSP21, indicating that the Jumeigui grapevines could not counter the heat stress. These were some differences in PSII activity and the expression of heat response genes between the two cultivated conditions could be attributed to other environmental factors, inherent plant vigor, and the adaptation mechanism.

MTHFR, TGFB3, and TGFA polymorphisms and their association with the risk of non-syndromic cleft lip and cleft palate in China.

Our previous results indicated a moderate association between the methylenetetrahydrofolate reductase (MTHFR) gene 677C-T variant and an increased risk of non-syndromic cleft lip with or without cleft palate (nsCL/P) among the northern but not southern population in China, suggesting possible genetic heterogeneity in the etiology of nsCL/P between these two populations. It remains unknown whether the transforming growth factor alpha (TGFA) gene TaqI polymorphism and transforming growth factor beta 3 (TGFB3) gene CA repeats influence the risk of nsCL/P differently between the northern and southern Chinese populations. In this study of 188 Chinese case-parent triads, we found an independent association between the TGFB3 variant and risk of nsCL/P (OR = 2.10, 95% CI: 1.25-3.54 for heterozygotes; OR = 1.78, 95% CI: 0.83-3.83 for homozygotes). The MTHFR variant was associated with an increased risk of nsCL/P among children in the north (OR = 3.11, 95% CI: 1.18-8.23 for heterozygotes; OR = 3.36, 95%CI: 1.14-9.93 for homozygotes) and appear to interact marginally with the TGFB3 variant in the occurrence of nsCL/P among southern subjects (OR = 0.26, 95% CI: 0.06-1.07). No association was found between the TGFA variant and risk of nsCL/P in our data. Our results suggest that the TGFB3 gene variant may be an important genetic risk factor for nsCL/P occurrence in Chinese children, and we found no evidence of heterogeneity between northern and southern Chinese populations in the associations between TGFB3 and TGFA variants and risk of nsCL/P, but these results warrant further investigation.

Plasma folate status and dietary folate intake among Chinese women of childbearing age.

Maternal folic acid deficiency is an underlying risk for neural tube defects (NTDs). China has one of the highest prevalences of NTDs, and the prevalence rates of NTDs vary by region. We characterized plasma folate level and dietary folate intake among Chinese women of childbearing age by region (North and South, East and West, urban and rural) to provide evidence for establishing policy to prevent NTDs. A total of 1003 women of childbearing age from five provinces in China were interviewed. Fasting blood samples were collected. Plasma folate concentrations were determined by a microbiological assay. Dietary intake data were collected using a 24-h recall. Both the plasma folate concentrations and dietary folate intake of women in the South (25.9 nmol L(-1) and 211.0 microg day(-1)) were higher than those of women in the North (13.3 nmol L(-1) and 189.2 microg day(-1)). In the North, plasma folate concentrations and dietary folate intake of women in rural areas were lower than those of women in urban areas, whereas, in the South, an opposite pattern was observed. No difference was found between women in the East and West, in either the North or South regions. Plasma folate and dietary folate intake among Chinese women of childbearing age were suboptimal and varied by region. Different folic acid supplementation approaches and dosage should be undertaken to improve folate status of women in different areas. Particular attention should be paid to women in the North, especially in northern rural areas.

Vitamin B-12 deficiency is prevalent in 35- to 64-year-old Chinese adults.

Low vitamin B-12 status alone, or in combination with low folate status, is related to neural tube defects (NTD) and hyperhomocysteinemia, a risk factor for atherosclerotic disease, but little is known about vitamin B-12 status in Chinese adults. In a cross-sectional study, we measured plasma vitamin B-12 in 2407 apparently healthy Chinese men and women, 35-64 y old, living in the south and the north of China. Plasma vitamin B-12 concentrations were lower among the northerners than the southerners (geometric means, 209 vs. 309 pmol/L, P < 0.001). Controlling for gender, age, season (spring and fall), and area (urban and rural) had little impact on the difference. We estimated that 11% of the southerners and 39% of the northerners had plasma vitamin B-12 concentrations <185 pmol/L, a level to define vitamin B-12 deficiency. Within each region, men had lower plasma vitamin B-12 concentrations and higher prevalence of vitamin B-12 deficiency than women (279 vs. 333 pmol/L and 15 vs. 8% in the south; 192 vs. 233 pmol/L and 47 vs. 34% in the north; P < 0.001 for all the differences). Low intakes of animal-based food, especially fish and dairy products, were significantly associated with vitamin B-12 deficiency. In the north, 59% of the participants were deficient in either folate (<6.8 nmol/L) or vitamin B-12, and 17% had deficiency in both. The corresponding rates were 16 and 1% in the southerners. To our knowledge, our findings provide the first evidence that vitamin B-12 deficiency is common in 35- to 64-y-old Chinese adults, especially in the north. Further studies are needed to evaluate the health effects and possible intervention strategies in areas where B-12 vitamin deficiency is common.

Comparison of blood folate levels among pregnant Chinese women in areas with high and low prevalence of neural tube defects.

OBJECTIVE: To characterise plasma and red-blood-cell (RBC) folate status among pregnant women in an area with an extremely high prevalence of neural tube defects, and to compare them with those of women from a low prevalence area. DESIGN: A cross-sectional survey conducted in 2003. SETTING: One county and one city from each of the high prevalence area and the low prevalence area in China. SUBJECTS: Five hundred and sixty-two women in their first trimester of pregnancy in the high prevalence area and 695 pregnant women in the low prevalence area. RESULTS: Women in the high prevalence area had less than half the plasma and RBC folate concentrations (12.2 and 440.0 nmol l- 1, respectively) of women in the low prevalence area (33.5 and 910.4 nmol l- 1, respectively). In the high prevalence area, 40% of rural women were deficient in RBC folate and 50% were deficient in plasma folate; 20% of urban women were deficient in RBC folate and 30% deficient in plasma folate. In contrast, only 4% (RBC folate) and 6% (plasma folate) of rural women, and 2% (RBC folate) and 1% (plasma folate) of urban women, were folate-deficient in the low prevalence area. Less than 10% of rural and about 26% of urban women in the high prevalence area took folic acid periconceptionally, compared with 70% and 60% of women in the low prevalence area. CONCLUSIONS: Blood folate deficiency is highly prevalent among pregnant women in an area of China with a very high prevalence of neural tube defects.

High prevalence of hyperhomocysteinemia in Chinese adults is associated with low folate, vitamin B-12, and vitamin B-6 status.

Elevated plasma total homocysteine (tHcy) concentrations are associated with lower folate, vitamin B-12, and vitamin B-6 status and are considered an independent risk factor for cardiovascular disease in developed countries, but data in developing countries are limited. We conducted a cross-sectional study to explore tHcy status and its association with plasma B vitamin status in 2471 Chinese men and women aged 35 to 64 y, living in the urban and rural areas of the northern and the southern regions of China. Blood samples were also collected in 2 seasons (spring and fall). The geometric mean plasma tHcy concentration was significantly higher in the north (adjusted geometric mean, 95% CI; 13.0 micromol/L, 12.6-13.3) than in the south (9.1, 8.9-9.4) after controlling for gender, area (urban and rural), age, and season (spring and fall). Twenty-eight percent of northerners and 7% of southerners had plasma tHcy concentrations>or=16.0 micromol/L, a level used to define hyperhomocysteinemia. Within each region, men had higher plasma tHcy concentrations than women (16.1 vs. 10.6 micromol/L in the north, and 10.7 vs. 7.9 micromol/L in the south) and 40% of the northern men had hyperhomocysteinemia. Generally, individuals living in the urban areas had 30% (95% CI, 1.0-1.6) greater odds of having high tHcy levels (>or=16 micromol/L) than those living in the rural areas. Low plasma concentrations of folate, vitamins B-12 and B-6, older age, being male, and living in urban areas were all independently associated with elevated tHcy, with low folate as the strongest determinant.

[Plasma and red blood cell folate levels among women in their first trimester of pregnancy from rural areas with high or low prevalence of neural tube defects, China].

OBJECTIVE: To compare plasma and red blood cell folate levels among women in their first trimester of pregnancy from rural areas with high or low prevalence of neural tube defects. METHODS: A cross-sectional study was performed, among women in their first trimester of pregnancy from rural areas with high or low prevalence of neural tube defects in 2003. Non-fasting blood sample were collected and analyzed for plasma and red blood cell folate concentrations for 688 women. RESULTS: The median plasma (10.53 nmol/L) and red blood cell folate (389.2 nmol/L) among women from the high prevalence rural area were lower than those of women from the low prevalence rural area (plasma folate: 30.39 nmol/L, red blood cell level folate: 926.0 nmol/L). Among women from the high prevalence area, about 50% and 43% were respectively, deficient for plasma and red blood cell folate, compared with 6% and 4% respectively, for women from the low prevalence area. The median plasma folate levels among women who took periconceptional folic acid supplements in both high and low prevalence areas were about twice higher than those who did not take the folic acid. The median red blood cell folate level of the folic acid users was 40% higher than those of the non-users. Among those who took folic acid, women in the low prevalence area had 70%-90% higher plasma folate concentration and twice higher red cell folate concentration than women in the high prevalence area. CONCLUSION: Women from the rural area with a high prevalence of neural tube defects had low plasma and red blood cell folate levels. Periconceptional supplementation with folic acid could substantially improve folate status of reproductive-aged women. However, supplementation with 0.4 mg of folic acid per day might be inadequate for women in the high prevalence rural area.

Folate concentrations and folic acid supplementation among women in their first trimester of pregnancy in a rural area with a high prevalence of neural tube defects in Shanxi, China.

BACKGROUND: Although an information campaign concerning periconceptional folic acid supplementation was launched in 1998 in Shanxi Province, China, the prevalence of neural tube defects in rural areas was reported as high as 140 per 10,000 births in 2002. The blood folate concentrations and the practice of folic acid supplementation among pregnant women in rural areas of the province are described. METHODS: A total of 483 pregnant women (mean gestation, 8.1 weeks) in a rural area of Shanxi were interviewed. Nonfasting blood samples and information on folic acid supplementation were collected. Folate concentrations in plasma and erythrocytes were determined by a microbiological assay. RESULTS: The mean concentrations of plasma and erythrocyte folate for pregnant women was 10.4 nmol/liter and 375.8 nmol/liter, respectively. Deficiencies of plasma and erythrocyte folate were observed in 20.9% and 47.6% of women, respectively. Seasonal variations were noted in the prevalence of folate deficiency, with significantly lower plasma folate concentrations in spring and summer and lower erythrocyte folate concentrations in seasons other than summer. Among pregnant women, <10% reported having taken or currently taking folic acid, and virtually no women (0.6%) took folic acid as recommended. CONCLUSIONS: Women in rural areas had low plasma and erythrocyte folate levels, and folate deficiency was highly prevalent in the area. Few women followed the recommendations regarding folic acid supplementation, and the information campaign in Shanxi was unsuccessful. These findings suggest the urgent need for combined strategies in rural areas to fortify grain with folic acid and promote folic acid supplements for childbearing-age women.

Awareness and use of folic acid, and blood folate concentrations among pregnant women in northern China--an area with a high prevalence of neural tube defects.

BACKGROUND: The prevalence of neural tube defects (NTDs) in northern China remains high after 10 years since periconceptional supplementation with folic acid has been known to be effective in reducing the risk of NTDs. OBJECTIVE: The objectives of this study were to characterize folic acid awareness and use and to examine the association between folic acid supplementation with blood folate concentrations among early pregnant women in an area with a high prevalence of NTDs in northern China. SUBJECT AND METHOD: From December 2002 to February 2004, 693 early pregnant women were recruited and interviewed about folic acid awareness, knowledge and use. Four millilitres of venous blood was drawn and blood folate concentrations were measured. RESULTS: About 36% of women reported having ever heard of folic acid. Of these, 82.7% knew that folic acid can prevent NTDs, and 64.5% knew the best time to take it. Overall, 15% of women reported having ever taken folic acid. However, only 34.3% had begun to take it before the last menstrual period. Women with less education (21.1%), farmers (19.6%), rural dwellers (23.5%), and women who had a previous child (23.0%) were less likely to be aware of folic acid, and were less likely to take folic acid. Among women who had ever heard of folic acid, 37.5% took it during current pregnancy, compared with only 2.0% among those who had not. Women who were aware of folic acid were 25 times more likely to take it than women who were not. Overall, 44% of women had plasma folate deficiency, and 35% had red cell folate deficiency. Those who reported having ever taken folic acid had a lower rate of plasma folate deficiency (13.7%), compared with those who reported not taking folic acid (49.4%). The former group's mean plasma concentrations were twice as high as those of the latter group. CONCLUSION: The levels of folic acid awareness, knowledge and use among Chinese women living in a high NTD prevalence area during early pregnancy were very low and folate deficiency was quite prevalent. Campaigns aimed at increasing the awareness, knowledge, and periconceptional use of folic acid should target to less educated, parous women and women living in rural areas.

[Comparative study of the detection of plasma folate with microbial assay and radioimmunoassay].

OBJECTIVE: To compare two methods (microbial assay and radioimmunoassay) for measuring plasma folate concentrations, and to examine the relationship between plasma folate levels, and alcohol consumption, tobacco use and body mass index, and the risk of hyperhomocysteinemia in China. METHODS: We used a microtiter plate microbial assay and a radioimmunoassay to measure the folate concentration in 88 plasma samples. After comparing the results of these two methods and fitting a regression line, we examined the geographical, seasonal, and gender differences in folate concentration of plasma collected from 2,422 adults in south and north areas in China, and evaluated the association of plasma folate concentration, with alcohol consumption, cigarette smoking, and body mass index, and with the risk of hyperhomocysteinemia, using the data from the two assays. RESULTS: The data from the two assays had a linear relationship (r=0.879, P=0.000); the regression was Y=0.683X+0.308 (where X and Y were nature logarithmic transformations of plasma folate by microbial assay and radioimmunoassay, respectively); however, the mean plasma folate levels by microbial assay were much higher than those obtained by radioimmunoassay. Both data sets showed similar plasma folate distributions among Chinese adults, associations with other risk factors, and the risk of hyperhomocysteinemia. We estimated that 19.9% of the Southerners and 67.1% of the Northerners had plasma folate concentrations by radioimmunoassay lower than the 6.8 nmol/L used to define plasma folate deficiency. CONCLUSION: There is a linear relationship between plasma folate levels determined by microbial assay and radioimmunoassay, but because of the different levels obtained in the two assays, it is difficult to use the microbial assay results to evaluate folate status at this time. The use of 10.5 nmol/L as a cut-off for plasma folate deficiency by microbial assay needs further study.

Geographical, seasonal and gender differences in folate status among Chinese adults.

Low blood folate concentrations have been associated with cardiovascular disease, neural tube defects and selected cancers, but little is known about folate status in Chinese adults. In a cross-sectional study we measured the plasma and red blood cell folate concentrations in 2422 Chinese men and women aged 35 to 64 y, living in the North and South of China, who provided blood samples either in March or September of 2001. The geometric mean concentrations of plasma and red blood cell folate were lower among Northerners than Southerners (adjusted geometric means, 8.4 and 502, and 16.7 and 811 nmol/L, respectively) controlling for age, gender, season (spring and fall), area (urban and rural), BMI, multivitamin use, alcohol intake and current smoking status. We estimated that approximately 40% of the Northerners and approximately 6% of the Southerners had plasma folate concentrations lower than the 6.8 nmol/L (3 microg/L), and approximately 30% of the Northerners and approximately 4% of the Southerners had red blood cell folate concentrations lower than the 363 nmol/L (160 microg/L), levels used to define folate deficiency. Within each region, men had lower plasma folate concentrations than women (6.9 versus 9.8 nmol/L in the North, and 14.5 versus 19.6 nmol/L in the South). In men, current smokers had a higher risk of folate deficiency compared with nonsmokers [adjusted odds ratios, 1.9 (95% CI, 1.4-2.6) for plasma folate deficiency and 2.5 (95% CI, 1.7-3.6) for red blood cell folate deficiency (P < 0.001)]. Our findings suggest that a large proportion of Chinese adults have a low folate status, especially those living in northern China where 60% of the men are plasma folate deficient in the spring. Further studies are needed to elucidate the factors that influence folate concentrations among middle-aged Chinese and to evaluate possible intervention strategies.

[Variation of plasma folate levels in adults between some areas and different seasons in China].

OBJECTIVE: To describe the distribution of plasma folate concentrations and prevalence of folate deficiency in adults aged 35 to 64 years in some areas and different seasons in China. METHODS: Study subjects were sampled from the representative rural and urban areas in the south and north of China aged 35 to 64 years totaling 2 545, and their plasma folate concentrations were determined and analyzed. RESULTS: Plasma concentrations of folate in the southern population were significantly higher (16.9 nmol/L) than those in the north (8.3 nmol/L), and the prevalence of folate deficiency in the south (5.8%) was significantly lower than that in the north (37.1%). Plasma folate concentration varied with season either in the south or north. Plasma concentrations of folate were lower during the summer and the fall (15.0 nmol/L) than those during the winter and the spring (18.8 nmol/L) in the south, but without significant changes in the prevalence of folate deficiency in different seasons. However, the plasma folate concentrations were significantly higher during the summer and the fall (9.7 nmol/L) than those during the winter and the spring (7.1 nmol/L) in the north. And the prevalence of folate deficiency in the north was significantly higher in winter and spring (48.0%) than that in summer and fall (26.2%). CONCLUSIONS: There existed significant difference in plasma folate concentrations in adults between varied geographic areas in China, which differed from their seasonal changes.