Mucosal-associated invariant T (MAIT) cells are an abundant innate-like T lymphocyte population that are enriched in liver and mucosal tissues. They are restricted by MR1, which presents antigens derived from a metabolic precursor of riboflavin synthesis, a pathway present in many microbial species, including commensals. Therefore, MR1-mediated MAIT cell activation must be tightly regulated to prevent inappropriate activation and immunopathology. Using an in vitro model of MR1-mediated activation of primary human MAIT cells, we investigated the mechanisms by which it is regulated. Uptake of intact bacteria by antigen presenting cells (APCs) into acidified endolysosomal compartments was required for efficient MR1-mediated MAIT cell activation, while stimulation with soluble ligand was inefficient. Consistent with this, little MR1 was seen at the surface of human monocytic (THP1) and B-cell lines. Activation with a TLR ligand increased the amount of MR1 at the surface of THP1 but not B-cell lines, suggesting differential regulation in different cell types. APC activation and NF-κB signaling were critical for MR1-mediated MAIT cell activation. In primary cells, however, prolonged TLR signaling led to downregulation of MR1-mediated MAIT cell activation. Overall, MR1-mediated MAIT cell activation is a tightly regulated process, dependent on integration of innate signals by APCs.

Cisplatin is a widely used anticancer drug. It is documented that it elicits major side effects like nephrotoxicity and hepatotoxicity due to oxidative stress forcing the patients to limit its clinical use in long term treatment. Riboflavin (vitamin B(2)) is a strong photosensitizer because it generates reactive oxygen species (ROS) upon photoillumination. We have tried to trap its photosensitizing property to ameliorate the cisplatin induced nephrotoxicity and hepatotoxicity in mice. They were treated with riboflavin and cisplatin separately as well as with their combination under photoilluminated condition. The status of major antioxidant enzymes, antioxidant proteins, functional markers, lipid peroxidation and protein oxidation was studied in liver, kidneys and serum samples of all the groups. Cisplatin treated group showed significantly compromised level of antioxidant enzymes and the proteins with higher extent of lipid and protein oxidation. Similar but less pronounced pattern was observed in the riboflavin treated group. The groups treated with the combination of cisplatin and riboflavin showed all the parameters tended towards normal levels in a dose dependent manner. Hence, it can be hypothesized that riboflavin shows ameliorative effect on the cisplatin induced nephrotoxicity and hepatotoxicity under the mentioned treatment conditions.

OBJECTIVE

To assess the impact of the Child and Adult Care Food Program (CACFP) on diet and 3 health outcomes--weight-for-height status, dental caries (tooth decay) score, and number of days of illness--among preschool children attending 2 urban day care centers.

METHODS

Dietary intake and health outcome measures were assessed and compared for children attending 2 day-care centers in an urban community. Data were obtained for 14 days of dietary intake, which were analyzed for energy and 15 nutrients and 6 food groups; anthropometric measures, including weight-for-height; dental caries; and days of illness.

METHODS

Forty 3- to 5-year-old black children from 2 day-care centers participated. One center participates in the CACFP. At the other center, children bring all meals and snacks from home.

METHODS

Data from the 2 groups of children were compared using parameteric and nonparametric t tests.

RESULTS

Children receiving CACFP meals at day care had significantly higher mean daily intakes of vitamin A (804 +/- 191 vs 595 +/- 268 retinol equivalents), riboflavin (1.45 +/- 0.32 vs 1.21 +/- 0.22 mg), and calcium (714 +/- 180 vs 503 +/- 143 mg) than the children who brought all of their meals and snacks from home. Children who received CACFP meals also consumed significantly more servings of milk (2.9 +/- 0.9 servings vs 1.5 +/- 0.7) and vegetables (1.8 +/- 0.5 vs 1.2 +/- 0.5 servings) and significantly fewer servings of fats/sweets (4.6 +/- 1.3 vs 5.4 +/- 1.1 servings) than children who brought their meals. Weight-for-height status and dental caries scores did not differ between the 2 groups. Children from the center participating in the CACFP have significantly fewer days of illness (median 6.5 vs 10.5 days) than children from the nonparticipating center.

CONCLUSIONS

Nutritious meals provided by the CACFP can improve diets and may promote health among young, urban children. Registered dietitians can contribute to food assistance programs by intervening to enhance the quality of meals served and by examining the impact of participation on measures of diet quality and diet-related health outcomes.

Predatory bacteria are taxonomically disparate, exhibit diverse predatory strategies and are widely distributed in varied environments. To date, their predatory phenotypes cannot be discerned in genome sequence data thereby limiting our understanding of bacterial predation, and of its impact in nature. Here, we define the 'predatome,' that is, sets of protein families that reflect the phenotypes of predatory bacteria. The proteomes of all sequenced 11 predatory bacteria, including two de novo sequenced genomes, and 19 non-predatory bacteria from across the phylogenetic and ecological landscapes were compared. Protein families discriminating between the two groups were identified and quantified, demonstrating that differences in the proteomes of predatory and non-predatory bacteria are large and significant. This analysis allows predictions to be made, as we show by confirming from genome data an over-looked bacterial predator. The predatome exhibits deficiencies in riboflavin and amino acids biosynthesis, suggesting that predators obtain them from their prey. In contrast, these genomes are highly enriched in adhesins, proteases and particular metabolic proteins, used for binding to, processing and consuming prey, respectively. Strikingly, predators and non-predators differ in isoprenoid biosynthesis: predators use the mevalonate pathway, whereas non-predators, like almost all bacteria, use the DOXP pathway. By defining predatory signatures in bacterial genomes, the predatory potential they encode can be uncovered, filling an essential gap for measuring bacterial predation in nature. Moreover, we suggest that full-genome proteomic comparisons are applicable to other ecological interactions between microbes, and provide a convenient and rational tool for the functional classification of bacteria.

Riboflavin (RF), also known as vitamin B2, belongs to the class of water-soluble vitamins and is widely present in a variety of food products. It is sensitive to light and high temperature, and therefore, needs a consideration of these factors for its stability in food products and pharmaceutical preparations. A number of other factors have also been identified that affect the stability of RF. These factors include radiation source, its intensity and wavelength, pH, presence of oxygen, buffer concentration and ionic strength, solvent polarity and viscosity, and use of stabilizers and complexing agents. A detailed review of the literature in this field has been made and all those factors that affect the photo, thermal and chemical degradation of RF have been discussed. RF undergoes degradation through several mechanisms and an understanding of the mode of photo- and thermal degradation of RF may help in the stabilization of the vitamin. A general scheme for the photodegradation of RF is presented.

BACKGROUND

Keratoconus is a condition of the eye that affects approximately 1 in 2000 people. The disease leads to a gradual increase in corneal curvature and decrease in visual acuity with consequent impact on quality of life. Collagen cross-linking (CXL) with ultraviolet A (UVA) light and riboflavin (vitamin B2) is a relatively new treatment that has been reported to slow or halt the progression of the disease in its early stages.

OBJECTIVE

The objective of this review was to assess whether there is evidence that CXL is an effective and safe treatment for halting the progression of keratoconus compared to no treatment.

METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL; 2014, Issue 7), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to August 2014), EMBASE (January 1980 to August 2014), Latin American and Caribbean Health Sciences Literature Database (LILACS) (1982 to August 2014), Cumulative Index to Nursing and Allied Health Literature (CINAHL) (1982 to August 2014), OpenGrey (System for Information on Grey Literature in Europe) (www.opengrey.eu/), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov) and the World Health Organisation International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We used no date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 28 August 2014.

METHODS

We included randomised controlled trials (RCTs) where CXL with UVA light and riboflavin was used to treat people with keratoconus and was compared to no treatment.

METHODS

Two review authors independently screened the search results, assessed trial quality, and extracted data using standard methodological procedures expected by Cochrane. Our primary outcomes were two indicators of progression at 12 months: increase in maximum keratometry of 1.5 dioptres (D) or more and deterioration in uncorrected visual acuity of more than 0.2 logMAR.

RESULTS

We included three RCTs conducted in Australia, the United Kingdom, and the United States that enrolled a total of 225 eyes and analysed 219 eyes. The total number of people enrolled was not clear in two of the studies. Only adults were enrolled into these studies. Out of the eyes analysed, 119 had CXL (all using the epithelium-off technique) and 100 served as controls. One of these studies only reported comparative data on review outcomes. All three studies were at high risk for performance bias (lack of masking), detection bias (only one trial attempted to mask outcome assessment), and attrition bias (incomplete follow-up). It was not possible to pool data due to differences in measuring and reporting outcomes. We identified a further three unpublished trials that potentially had enrolled a total of 195 participants.There was limited evidence on the risk of progression. Analysis of the first few participants followed up to one year in one study suggested that eyes given CXL were less likely to have an increase in maximum keratometry of 1.5 D or more at 12 months compared to eyes given no treatment, but the confidence intervals (CI) were wide and compatible with no effect or more progression in the CXL group (risk ratio (RR) 0.12, 95% CI 0.01 to 2.00, 19 eyes). The same study reported the number of eyes with an increase of 2 D or more at 36 months in the whole cohort with a RR of 0.03 favouring CXL (95% CI 0.00 to 0.43, 94 eyes). Another study reported "progression" at 18 months using a different definition; people receiving CXL were less likely to progress, but again the effect was uncertain (RR 0.14, 95% CI 0.01 to 2.61, 44 eyes). We judged this to be very low-quality evidence due to the risk of bias of included studies, imprecision, indirectness and publication bias but noted that the size of the potential effect was large.On average, treated eyes had a less steep cornea (approximately 2 D less steep) (mean difference (MD) -1.92, 95% CI -2.54 to -1.30, 94 eyes, 1 RCT, very low-quality evidence) and better uncorrected visual acuity (approximately 2 lines or 10 letters better) (MD -0.20, 95% CI -0.31 to -0.09, 94 eyes, 1 RCT, very low-quality evidence) at 12 months. None of the studies reported loss of 0.2 logMAR acuity. The data on corneal thickness were inconsistent. There were no data available on quality of life or costs. Adverse effects were not uncommon but mostly transient and of low clinical significance. In one trial, 3 out of 12 participants treated with CXL had an adverse effect including corneal oedema, anterior chamber inflammation, and recurrent corneal erosions. In one trial at 3 years 3 out of 50 participants experienced adverse events including mild diffuse corneal oedema and paracentral infiltrate, peripheral corneal vascularisation, and subepithelial infiltrates and anterior chamber inflammation. No adverse effects were reported in the control groups.

CONCLUSIONS

The evidence for the use of CXL in the management of keratoconus is limited due the lack of properly conducted RCTs.

1. A new method is described for the measurement of d-2-hydroxy acid dehydrogenase in samples of animal tissues. 2. The distribution of the enzyme in a number of animals was determined. Of the animal tissues tested, the most active source of the enzyme was found to be rabbit kidney cortex. 3. The enzyme was purified from rabbit kidney to a stage at which it appears to be homogeneous in the analytical ultracentrifuge and on polyacrylamide-gel electrophoresis. 4. The molecular weight was estimated by gel filtration to be approx. 102000; combination of gelfiltration data and the sedimentation coefficient gave a value of 95000. 5. The purified enzyme has a spectrum typical of a flavoprotein. The change induced in the spectrum on addition of d-malate or d-lactate suggests the formation of a flavin semiquinone. 6. Flavin can be removed by treatment with acid ammonium sulphate, and activity can be restored to the inactive apoenzyme by addition of FAD, but not of FMN or riboflavin. 7. Studies of acceptor specificity showed that the enzyme has a relatively weak d-2-hydroxy acid oxidase activity.

BACKGROUND

Changes in immune function believed to contribute to a variety of age-related diseases have been associated with increased production of nitric oxide (NO). We have recently reported that proteasome inhibitors (dexamethasone, mevinolin, quercetin, δ-tocotrienol, and riboflavin) can inhibit lipopolysaccharide (LPS)-induced NO production in vitro by RAW 264.7 cells and by thioglycolate-elicited peritoneal macrophages derived from four strains of mice (C57BL/6, BALB/c, LMP7/MECL-1(-/-) and PPAR-α(-/-) knockout mice). The present study was carried out in order to further explore the potential effects of diet supplementation with naturally-occurring inhibitors (δ-tocotrienol and quercetin) on LPS-stimulated production of NO, TNF-α, and other pro-inflammatory cytokines involved in the ageing process. Young (4-week-old) and senescent mice (42-week old) were fed control diet with or without quercetin (100 ppm), δ-tocotrienol (100 ppm), or dexamethasone (10 ppm; included as positive control for suppression of inflammation) for 4 weeks. At the end of feeding period, thioglycolate-elicited peritoneal macrophages were collected, stimulated with LPS, LPS plus interferon-β (IFN-β), or LPS plus interferon-γ (IFN-γ), and inflammatory responses assessed as measured by production of NO and TNF-α, mRNA reduction for TNF-α, and iNOS genes, and microarray analysis.

RESULTS

Thioglycolate-elicited peritoneal macrophages prepared after four weeks of feeding, and then challenged with LPS (10 ng or 100 ng) resulted in increases of 55% and 73%, respectively in the production of NO of 46-week-old compared to 8-week-old mice fed control diet alone (respective control groups), without affecting the secretion of TNF-α among these two groups. However, macrophages obtained after feeding with quercetin, δ-tocotrienol, and dexamethasone significantly inhibited (30% to 60%; P < 0.02) the LPS-stimulated NO production, compared to respective control groups. There was a 2-fold increase in the production of NO, when LPS-stimulated macrophages of quercetin, δ-tocotrienol, or dexamethasone were also treated with IFN-β or IFN-γ compared to respective control groups. We also demonstrated that NO levels and iNOS mRNA expression levels were significantly higher in LPS-stimulated macrophages from senescent (0.69 vs 0.41; P < 0.05), compared to young mice. In contrast, age did not appear to impact levels of TNF-α protein or mRNA expression levels (0.38 vs 0.35) in LPS-stimulated macrophages. The histological analyses of livers of control groups showed lesions of peliosis and microvesicular steatosis, and treated groups showed Councilman body, and small or large lymphoplasmacytic clusters.

CONCLUSIONS

The present results demonstrated that quercetin and δ-tocotrienols inhibit the LPS-induced NO production in vivo. The microarray DNA analyses, followed by pathway analyses indicated that quercetin or δ-tocotrienol inhibit several LPS-induced expression of several ageing and pro-inflammatory genes (IL-1β, IL-1α, IL-6, TNF-α, IL-12, iNOS, VCAM1, ICAM1, COX2, IL-1RA, TRAF1 and CD40). The NF-κB pathway regulates the production of NO and inhibits the pro-inflammatory cytokines involved in normal and ageing process. These ex vivo results confirmed the earlier in vitro findings. The present findings of inhibition of NO production by quercetin and δ-tocotrienol may be of clinical significance treating several inflammatory diseases, including ageing process.

We used comparative genomics to elucidate the genome evolution within the pre-whole-genome duplication genus Eremothecium. To this end, we sequenced and assembled the complete genome of Eremothecium cymbalariae, a filamentous ascomycete representing the Eremothecium type strain. Genome annotation indicated 4712 gene models and 143 tRNAs. We compared the E. cymbalariae genome with that of its relative, the riboflavin overproducer Ashbya (Eremothecium) gossypii, and the reconstructed yeast ancestor. Decisive changes in the Eremothecium lineage leading to the evolution of the A. gossypii genome include the reduction from eight to seven chromosomes, the downsizing of the genome by removal of 10% or 900 kb of DNA, mostly in intergenic regions, the loss of a TY3-Gypsy-type transposable element, the re-arrangement of mating-type loci, and a massive increase of its GC content. Key species-specific events are the loss of MNN1-family of mannosyltransferases required to add the terminal fourth and fifth α-1,3-linked mannose residue to O-linked glycans and genes of the Ehrlich pathway in E. cymbalariae and the loss of ZMM-family of meiosis-specific proteins and acquisition of riboflavin overproduction in A. gossypii. This reveals that within the Saccharomyces complex genome, evolution is not only based on genome duplication with subsequent gene deletions and chromosomal rearrangements but also on fungi associated with specific environments (e.g. involving fungal-insect interactions as in Eremothecium), which have encountered challenges that may be reflected both in genome streamlining and their biosynthetic potential.

Folate intake has shown an inverse association with pancreatic cancer; nevertheless, results from plasma measurements were inconsistent. The aim of this study is to examine the association between plasma total homocysteine, methionine, folate, cobalamin, pyridoxal 5'-phosphate, riboflavin, flavin mononucleotide and pancreatic cancer risk in the European Prospective Investigation into Cancer and Nutrition (EPIC). We conducted a nested case-control study in the EPIC cohort, which has an average of 9.6 years of follow-up (1992-2006), using 463 incident pancreatic cancer cases. Controls were matched to each case by center, sex, age (± 1 year), date (± 1 year) and time (± 3 h) at blood collection and fasting status. Conditional logistic regression was used to calculate the odds ratios (OR) and 95% confidence intervals (CI), adjusting for education, smoking status, plasma cotinine concentration, alcohol drinking, body mass index and diabetes status. We observed a U-shaped association between plasma folate and pancreatic cancer risk. The ORs for plasma folate ≤ 5, 5-10, 10-15 (reference), 15-20, and>> 20 nmol/L were 1.58 (95% CI=0.72-3.46), 1.39 (0.93-2.08), 1.0 (reference), 0.79 (0.52-1.21), and 1.34 (0.89-2.02), respectively. Methionine was associated with an increased risk in men (per quintile increment: OR=1.17, 95% CI=1.00-1.38) but not in women (OR=0.91, 95% CI=0.78-1.07; p for heterogeneity <0.01). Our results suggest a U-shaped association between plasma folate and pancreatic cancer risk in both men and women. The positive association that we observed between methionine and pancreatic cancer may be sex dependent and may differ by time of follow-up. However, the mechanisms behind the observed associations warrant further investigation.

Brucellosis is a worldwide zoonosis that affects livestock and humans and is caused by closely related Brucella spp., which are adapted to intracellular life within cells of a large variety of mammals. Brucella can be considered a furtive pathogen that infects professional and non-professional phagocytes. In these cells Brucella survives in a replicative niche, which is characterized for having a very low oxygen tension and being deprived from nutrients such as amino acids and vitamins. Among these vitamins, we have focused on riboflavin (vitamin B2). Flavin metabolism has been barely implicated in bacterial virulence. We have recently described that Brucella and other Rhizobiales bear an atypical riboflavin metabolic pathway. In the present work we analyze the role of the flavin metabolism on Brucella virulence. Mutants on the two lumazine synthases (LS) isoenzymes RibH1 and RibH2 and a double RibH mutant were generated. These mutants and different complemented strains were tested for viability and virulence in cells and in mice. In this fashion we have established that at least one LS must be present for B. abortus survival and that RibH2 and not RibH1 is essential for intracellular survival due to its LS activity in vivo. In summary, we show that riboflavin biosynthesis is essential for Brucella survival inside cells or in mice. These results highlight the potential use of flavin biosynthetic pathway enzymes as targets for the chemotherapy of brucellosis.

Osteoarthritis (OA) is characterized by remodeling and degradation of joint tissues. Microarray studies have led to a better understanding of the molecular changes that occur in tissues affected by conditions such as OA; however, such analyses are limited to the identification of a list of genes with altered transcript expression, usually at a single time point during disease progression. While these lists have identified many novel genes that are altered during the disease process, they are unable to identify perturbed relationships between genes and gene products. In this work, we have integrated a time course gene expression dataset with network analysis to gain a better systems level understanding of the early events that occur during the development of OA in a mouse model. The subnetworks that were enriched at one or more of the time points examined (2, 4, 8, and 16 weeks after induction of OA) contained genes from several pathways proposed to be important to the OA process, including the extracellular matrix-receptor interaction and the focal adhesion pathways and the Wnt, Hedgehog and TGF-β signaling pathways. The genes within the subnetworks were most active at the 2 and 4 week time points and included genes not previously studied in the OA process. A unique pathway, riboflavin metabolism, was active at the 4 week time point. These results suggest that the incorporation of network-type analyses along with time series microarray data will lead to advancements in our understanding of complex diseases such as OA at a systems level, and may provide novel insights into the pathways and processes involved in disease pathogenesis.

The levels and activities of cytochrome P450 enzymes are influenced by a variety of factors, including the diet. In this article, the effects of selected non-nutritive dietary chemicals, macronutrients, micronutrients, and ethanol on cytochromes P450 and xenobiotic metabolism are reviewed in the light of our current understanding of the multiplicity and substrate specificity of cytochrome P450 enzymes. Although the mechanisms of action of several dietary chemicals on specific cytochrome P450 isozymes have been established, those for macro- and micronutrients are largely unknown. It is known, however, that specific nutrients may have varied effects on different cytochrome P450 forms and thus may affect the metabolism of various drugs differently. Nutritional deficiencies generally cause lowered rates of xenobiotic metabolism. In certain cases, such as thiamin deficiency and mild riboflavin deficiency, however, enhanced rates of metabolism of xenobiotics were observed. The effects of dietary modulation of xenobiotic metabolism on chemical toxicity and carcinogenicity are discussed.

6,7-Dimethyl-8-ribityllumazine is the biosynthetic precursor of riboflavin, which, as a coenzyme, plays a vital role in the electron transfer process for energy production in all cellular organisms. The enzymes involved in lumazine biosynthesis have been studied in considerable detail. However, the conclusive mechanism of the reaction catalyzed by lumazine synthase has remained unclear. Here, we report four crystal structures of the enzyme from the hyperthermophilic bacterium Aquifex aeolicus in complex with different inhibitor compounds. The structures were refined at resolutions of 1.72 A, 1.85 A, 2.05 A and 2.2 A, respectively. The inhibitors have been designed in order to mimic the substrate, the putative reaction intermediates and the final product. Structural comparisons of the native enzyme and the inhibitor complexes as well as the kinetic data of single-site mutants of lumazine synthase from Bacillus subtilis showed that several highly conserved residues at the active site, namely Phe22, His88, Arg127, Lys135 and Glu138 are most likely involved in catalysis. A structural model of the catalytic process, which illustrates binding of substrates, enantiomer specificity, proton abstraction/donation, inorganic phosphate elimination, formation of the Schiff base and cyclization is proposed.

We have previously found BMD and fracture risk to be significantly associated with the MTHFR (C677T) polymorphism in healthy postmenopausal women in the first years after menopause. Since then, other cohort studies have suggested that sufficient intake of riboflavin and/or folate may have the potential to prevent development of low BMD in women with the TT genotype. This could to some extent explain why this polymorphism is associated with low BMD or fracture in some study populations and not in others. It would also indicate that fractures associated with the TT genotype could be preventable by vitamin B supplementation. We have, therefore, reviewed baseline food record data from our original study to determine if BMD and fracture associations with the MTHFR genotype depended on the intake of folate, riboflavin, or other members of the vitamin B complex, associated with homocysteine metabolism. We analyzed genotype, BMD, and dietary records from 1700 healthy postmenopausal women who participated in the DOPS study. For the assessment of fracture risk, we used longitudinal observations from 854 women in the control group who remained compliant with their initial allocation of no treatment. Riboflavin intake was significantly correlated with femoral neck (FN) BMD in women with the TT genotype (r = 0.24, P < 0.01). FN and lumbar spine (LS) BMD were only associated with the MTHFR genotype in the lowest quartile of riboflavin intake. At the FN, similar threshold effects were shown for folate, vitamin B12, and vitamin B6. Among these vitamin B complex members, stepwise regression analysis identified riboflavin as the only significant predictor of FN BMD in the TT genotype. In conclusion, we confirm reports that BMD in the MTHFR TT genotype is only significantly reduced in the lowest quartile of riboflavin, B12, B6, and folate intake, at least at the time of menopause. Vitamin B supplementation would only be expected to benefit BMD in about 2% of the population, i.e., those with the TT genotype and low vitamin B intake.

We investigated the associations between dietary intake of folate and vitamin B2, MTHFR C677T genotype, and colorectal adenomas in a Dutch case-control study. Data of cases with at least one histologically confirmed colorectal adenoma (n = 768) and controls with no history of any type of colorectal polyp (n = 709) were included. Dietary intake was assessed using a food-frequency questionnaire. Multivariable models included age and, if appropriate, dietary folate and calcium intake. The adjusted odds ratio (OR) and 95% confidence interval (CI) for the highest compared with the lowest sex-specific tertile of intake were 1.32 (95% CI, 1.01-1.73) for folate and 0.51 (95% CI, 0.36-0.73) for vitamin B2. Folate seemed to be a risk factor, especially when vitamin B2 intake was low; vitamin B2 was inversely associated with adenomas, especially with relatively high folate intake. No association was observed between MTHFR C677T genotype and colorectal adenomas. The inverse association between vitamin B2 intake and colorectal adenoma risk seemed to be more pronounced among those with the MTHFR TT genotype. We conclude that this study does not provide evidence for a decreased colorectal adenoma risk for subjects with high dietary intake of folate. It suggests, however, an inverse association between vitamin B2 and colorectal adenomas, which may be more relevant for those with the MTHFR TT genotype.

Deinococcus radiodurans R1, a red-pigmented strain of the extremely radioresistant genus Deinococcus, contains a major carotenoid namely deinoxanthin. The high resistance of this organism against the lethal actions of DNA-damaging agents including ionizing radiation and ultraviolet light (UV) has been widely reported. However, the possible antioxidant role of carotenoids in this strain has not been completely elucidated. In this study, we constructed two colorless mutants by knockout of crtB and crtI genes, respectively. Comparative analysis of the two colorless mutants and the wild type showed that the two colorless mutants were more sensitive to ionizing radiation, UV, and hydrogen peroxide, but not to mitomycin-C (MMC). With electron spin resonance (ESR) and spin trapping techniques, we observed that hydroxyl radical signals occurred in the suspensions of UV irradiated Deinococcus radiodurans cells and the intensity of signals was influenced by carotenoids levels. We further showed that the carotenoid extract from the wild type could obviously scavenge superoxide anions generated by the irradiated riboflavin/EDTA system. These results suggest that carotenoids in D. radiodurans R1 function as free radical scavengers to protect this organism against the deleterious effects of oxidative DNA-damaging agents.

In a hospital-based case-control study of common malignant epithelial tumors of the ovary, conducted in Athens (1989-1991), 189 cases were compared with 200 hospital visitor controls. Personal interviews were conducted in all cases and diet was ascertained through a semi-quantitative food frequency questionnaire. Nutrient intakes for individuals were estimated by multiplying the nutrient content of a typical portion size for each specified food item by the frequency at which the food was consumed per month and summing these estimates for all food items. Data were analyzed using logistic regression, controlling for non-dietary confounding factors, total energy intake and, among nutrients, mutual confounding influences. Adjusted odds ratios (rate ratios) for ovarian cancer, associated with particular nutritional variables, were expressed in terms of increments approximately equal to the standard deviations of (the residual of) the respective nutrients, on a daily basis. The adjusted odds ratios (and 95% confidence intervals) were 0.80 (0.65-0.99) for mono-unsaturated fat and 0.73 (0.61-0.87) for crude fiber. No substantial, statistically significant or consistent independent associations were noted for total energy, total protein, saturated fat, polyunsaturated fat, dietary cholesterol, total carbohydrates, sucrose, vitamin C, vitamin A, riboflavin or calcium. These associations, if causal, could explain to some extent the relatively low incidence of ovarian cancer in Greece and other Mediterranean countries as well as the increasing incidence trends noted in these countries during the last few decades.

Diabetes mellitus is associated with an increased production of reactive oxygen species and a reduction in antioxidant defenses. This leads to oxidative stress, which is partly responsible for diabetic complications. Tight glycemic control is the most effective way of preventing or decreasing these complications. Nevertheless, antioxidant micronutrients can be proposed as adjunctive therapy in patients with diabetes. Indeed, some minerals and vitamins are able to indirectly participate in the reduction of oxidative stress in diabetic patients by improving glycemic control and/or are able to exert antioxidant activity. This article reviews the use of minerals (vanadium, chromium, magnesium, zinc, selenium, copper) and vitamins or cofactors (tocopherol [vitamin E], ascorbic acid [vitamin C], ubidecarenone [ubiquinone; coenzyme Q], nicotinamide, riboflavin, thioctic acid [lipoic acid], flavonoids) in diabetes, with a particular focus on the prevention of diabetic complications. Results show that dietary supplementation with micronutrients may be a complement to classical therapies for preventing and treating diabetic complications. Supplementation is expected to be more effective when a deficiency in these micronutrients exists. Nevertheless, many clinical studies have reported beneficial effects in individuals without deficiencies, although several of these studies were short term and had small sample sizes. However, a randomized, double-blind, placebo-controlled, multicenter trial showed that thioctic acid at an oral dosage of 800 mg/day for 4 months significantly improved cardiac autonomic neuropathy in type 2 diabetic patients. Above all, individuals with diabetes should be educated about the importance of consuming adequate amounts of vitamins and minerals from natural food sources, within the constraints of recommended sugar and carbohydrate intake.

OBJECTIVE

Folate metabolism, with its importance to DNA repair, provides a promising region for genetic investigation of lung cancer risk. This project investigates genes (MTHFR, MTR, MTRR, CBS, SHMT1, TYMS), folate metabolism related nutrients (B vitamins, methionine, choline, and betaine) and their gene-nutrient interactions.

METHODS

We analyzed 115 tag single nucleotide polymorphisms (SNPs) and 15 nutrients from 1239 and 1692 non-Hispanic white, histologically-confirmed lung cancer cases and controls, respectively, using stochastic search variable selection (a Bayesian model averaging approach). Analyses were stratified by current, former, and never smoking status.

RESULTS

Rs6893114 in MTRR (odds ratio [OR] = 2.10; 95% credible interval [CI]: 1.20-3.48) and alcohol (drinkers vs. non-drinkers, OR = 0.48; 95% CI: 0.26-0.84) were associated with lung cancer risk in current smokers. Rs13170530 in MTRR (OR = 1.70; 95% CI: 1.10-2.87) and two SNP*nutrient interactions [betaine*rs2658161 (OR = 0.42; 95% CI: 0.19-0.88) and betaine*rs16948305 (OR = 0.54; 95% CI: 0.30-0.91)] were associated with lung cancer risk in former smokers. SNPs in MTRR (rs13162612; OR = 0.25; 95% CI: 0.11-0.58; rs10512948; OR = 0.61; 95% CI: 0.41-0.90; rs2924471; OR = 3.31; 95% CI: 1.66-6.59), and MTHFR (rs9651118; OR = 0.63; 95% CI: 0.43-0.95) and three SNP*nutrient interactions (choline*rs10475407; OR = 1.62; 95% CI: 1.11-2.42; choline*rs11134290; OR = 0.51; 95% CI: 0.27-0.92; and riboflavin*rs8767412; OR = 0.40; 95% CI: 0.15-0.95) were associated with lung cancer risk in never smokers.

CONCLUSIONS

This study identified possible nutrient and genetic factors related to folate metabolism associated with lung cancer risk, which could potentially lead to nutritional interventions tailored by smoking status to reduce lung cancer risk.

Of six strains of Ruminococcus bromii studied, five grew in a minimal chemically defined medium containing minerals, NH(4) (+) as nitrogen source, sulfide or sulfate as sulfur source, fructose as energy and carbon source, isobutyrate or 2-methylbutyrate and carbonic acid-bicarbonate as additional carbon sources, and the vitamins biotin, riboflavin, pyridoxine, vitamin B(12) (replaced by L-methionine), pantethine, and tetrahydrofolate. The strains also could utilize cysteine or thiosulfate but not methionine; and strain Z3 failed to use dithiothreitol, thioglycolate, sulfite, or beta-mercaptoethanol as sole sources of sulfur. Mixtures of amino acids, peptides (Casitone), urea, nitrate, asparagine, or glutamine failed to replace NH(4) (+) as N source. Three strains isolated from Americans were identical in nutritional features, whereas one from a Japanese and one from a South African native differed slightly in having requirements for fewer vitamins. One strain from the cecum of a sow grew well in a rumen fluid-supplemented medium but not in the various chemically defined media plus Casitone. The nutritional features suggest that the environment which selects R. bromii contains relatively little amino acid nitrogen and a relatively large amount of NH(4) (+)-N and indicate that these bacteria must depend upon other bacteria such as those that produce NH(4) (+) from urea or protein and those that produce branched-chain volatile acids to grow.

Keto acids and reduced-oxygen-scavenging enzymes were examined for their roles in supporting the growth of Legionella species and for their potential reactions between the chemical components of the media. When grown in an experimental ACES (2-[(2-amino-2-oxoethyl)-amino] ethanesulfonic acid)-buffered chemically defined (ABCD) broth, the presence of keto acids shortened the lag periods, increased the rates of growth, and gave maximum cell yields. In addition, keto acids affected the specific activities of reduced-oxygen-scavenging enzymes determined during growth. The specific activities of superoxide dismutase of Legionella pneumophila (Knoxville) and L. dumoffii (TEX-KL) were increased three- to eightfold, while that of L. bozemanii (WIGA) was not affected. All strains appeared to be equally sensitive to the effects of superoxide anion (O2-) generated by light-activated riboflavin, and all were equally protected by the presence of keto acids in the ABCD broth. Production of trace amounts of acetate and succinate in pyruvate- and alpha-ketoglutarate-containing media exposed to light suggested that hydrogen peroxide was formed. Pyruvate and alpha-ketoglutarate were products of growth on amino acids, and there was no quantitative evidence that these keto acids were metabolized when they were added to the medium. The rate of cysteine oxidation in ABCD broth was increased by the presence of ferric ion or by exposure to light or by both, and keto acids reduced the rate of this oxidation. ACES buffer was a substrate for the production of O2- in the presence of light, and the combined addition of Fe2+ ions, cysteine, and either keto acid to the medium strongly inhibited the production of O2-. Thus, keto acids inhibited the rate of cysteine oxidation, they stimulated rapid growth by an unknown process, and, in combination with added Fe2+ ions and cysteine, they reversed the toxic effects of light by inhibiting O2- production.

BACKGROUND

Case-control studies have suggested that a diet rich in fresh fruit and vegetables protects from the risk of most common epithelial cancers, including those of the digestive tract, and also several nondigestive neoplasms; however, selections in cohort studies have been generally weaker.

OBJECTIVE

To review the relation between frequency of consumption of vegetables and fruit, estimated intake of selected antioxidants and the risk of cancer at different sites.

METHODS

Systematic overview of data, with specific focus on a network of case-control studies conducted in Italy from 1983 to 1999.

RESULTS

The relative risks (RR) of digestive tract neoplasms were reduced in subjects reporting highest vegetable intake. A protective effect of vegetables was also observed for hormone-related neoplasms. Fruit was related to a reduced RR of cancers of the upper digestive tract, stomach and urinary tract. With reference to the role of selected antioxidants, beta-carotene, vitamins C and E showed a significant inverse relation with oral and pharyngeal, esophageal and breast cancer risk. Against colorectal cancer, the most consistent protective effects were provided by carotene, riboflavin and vitamin C, but inverse relations were observed also for calcium and vitamin D.

CONCLUSIONS

Fruit and vegetable consumption in Mediterranean populations appears to provide protection against several types of neoplasms.